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[E75, R78 and D82 of Escherichia coli FtsZ are key residues for FtsZ cellular self-assembly and FtsZ-MreB interaction].

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Huo, Yujia; Lu, Qiaonan; Zheng, Xiaowei; Ma, Yuanfang; Lu, Feng

2016-02-04

To explore effects of FtsZ mutants FtsZ(E75A), FtsZ(R78G) and FtsZ(D82A) on FtsZ self-assembly and interaction of FtsZ with MreB in Escherichia coli strains. METHODS) We constructed FtsZ and its mutant's plasmids by molecular clone and site-directed mutagenesis methods, and purified targeted proteins by affinity chromatography. QN6(ftsZ::yfp-cat), QN7(tsZ::yfp-cat), QN8(ftsZ(R78G)::yfp-cat) and QN9 (ftsZ(D82A):.:yfp-cat) strains were constructed by linear DNA homologous recombination. We observed cellular localization pattern of FtsZ and its mutants in E. coli by living cell imaging experiments, examined interaction of FtsZ/FtsZ*-FtsZ* and FtsZ/FtsZ*-MreB by Coimmunoprecipitation and bacteria two hybrid, and analyzed assembly characteristics of FtsZ mutants by Light scattering. RESULTS) The Yfp-labeled FtsZ(E75A), FtsZ(R78G) and FtsZ(D82A) mutant proteins failed to assemble into functional Z-ring structure and localize correctly in E. coli strains. Interaction of FtsZ with its mutants, or FtsZ*-FtsZ* and FtsZ*-MreB interaction were weakened or completely disappeared. In addition, in vitro experiments show that E75A, R78G and D82A mutations decreased the polymerization efficiency of FtsZ monomer. FtsZ E75, R78 and D82 are critical amino acids in the assembly, function of FtsZ protein and FtsZ-MreB interaction in E. coli strains.
In Escherichia coli, MreB and FtsZ direct the synthesis of lateral cell wall via independent pathways that require PBP 2.

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Varma, Archana; Young, Kevin D

2009-06-01

In Escherichia coli, the cytoplasmic proteins MreB and FtsZ play crucial roles in ensuring that new muropeptide subunits are inserted into the cell wall in a spatially correct way during elongation and division. In particular, to retain a constant diameter and overall shape, new material must be inserted into the wall uniformly around the cell's perimeter. Current thinking is that MreB accomplishes this feat through intermediary proteins that tether peptidoglycan synthases to the outer face of the inner membrane. We tested this idea in E. coli by using a DD-carboxypeptidase mutant that accumulates pentapeptides in its peptidoglycan, allowing us to visualize new muropeptide incorporation. Surprisingly, inhibiting MreB with the antibiotic A22 did not result in uneven insertion of new wall, although the cells bulged and lost their rod shapes. Instead, uneven (clustered) incorporation occurred only if MreB and FtsZ were inactivated simultaneously, providing the first evidence in E. coli that FtsZ can direct murein incorporation into the lateral cell wall independently of MreB. Inhibiting penicillin binding protein 2 (PBP 2) alone produced the same clustered phenotype, implying that MreB and FtsZ tether peptidoglycan synthases via a common mechanism that includes PBP 2. However, cell shape was determined only by the presence or absence of MreB and not by the even distribution of new wall material as directed by FtsZ.
FtsZ placement in nucleoid-free bacteria.

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Manuel Pazos

Full Text Available We describe the placement of the cytoplasmic FtsZ protein, an essential component of the division septum, in nucleoid-free Escherichia coli maxicells. The absence of the nucleoid is accompanied in maxicells by degradation of the SlmA protein. This protein, together with the nucleoid, prevents the placement of the septum in the regions occupied by the chromosome by a mechanism called nucleoid occlusion (NO. A second septum placement mechanism, the MinCDE system (Min involving a pole-to-pole oscillation of three proteins, nonetheless remains active in maxicells. Both Min and NO act on the polymerization of FtsZ, preventing its assembly into an FtsZ-ring except at midcell. Our results show that even in the total absence of NO, Min oscillations can direct placement of FtsZ in maxicells. Deletion of the FtsZ carboxyl terminal domain (FtsZ*, a central hub that receives signals from a variety of proteins including MinC, FtsA and ZipA, produces a Min-insensitive form of FtsZ unable to interact with the membrane-anchoring FtsA and ZipA proteins. This protein produces a totally disorganized pattern of FtsZ localization inside the maxicell cytoplasm. In contrast, FtsZ*-VM, an artificially cytoplasmic membrane-anchored variant of FtsZ*, forms helical or repetitive ring structures distributed along the entire length of maxicells even in the absence of NO. These results show that membrane anchoring is needed to organize FtsZ into rings and underscore the role of the C-terminal hub of FtsZ for their correct placement.
FtsZ placement in nucleoid-free bacteria.

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Pazos, Manuel; Casanova, Mercedes; Palacios, Pilar; Margolin, William; Natale, Paolo; Vicente, Miguel

2014-01-01

We describe the placement of the cytoplasmic FtsZ protein, an essential component of the division septum, in nucleoid-free Escherichia coli maxicells. The absence of the nucleoid is accompanied in maxicells by degradation of the SlmA protein. This protein, together with the nucleoid, prevents the placement of the septum in the regions occupied by the chromosome by a mechanism called nucleoid occlusion (NO). A second septum placement mechanism, the MinCDE system (Min) involving a pole-to-pole oscillation of three proteins, nonetheless remains active in maxicells. Both Min and NO act on the polymerization of FtsZ, preventing its assembly into an FtsZ-ring except at midcell. Our results show that even in the total absence of NO, Min oscillations can direct placement of FtsZ in maxicells. Deletion of the FtsZ carboxyl terminal domain (FtsZ*), a central hub that receives signals from a variety of proteins including MinC, FtsA and ZipA, produces a Min-insensitive form of FtsZ unable to interact with the membrane-anchoring FtsA and ZipA proteins. This protein produces a totally disorganized pattern of FtsZ localization inside the maxicell cytoplasm. In contrast, FtsZ*-VM, an artificially cytoplasmic membrane-anchored variant of FtsZ*, forms helical or repetitive ring structures distributed along the entire length of maxicells even in the absence of NO. These results show that membrane anchoring is needed to organize FtsZ into rings and underscore the role of the C-terminal hub of FtsZ for their correct placement.
Direct interaction of FtsZ and MreB is required for septum synthesis and cell division in Escherichia coli.

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Fenton, Andrew K; Gerdes, Kenn

2013-07-03

How bacteria coordinate cell growth with division is not well understood. Bacterial cell elongation is controlled by actin-MreB while cell division is governed by tubulin-FtsZ. A ring-like structure containing FtsZ (the Z ring) at mid-cell attracts other cell division proteins to form the divisome, an essential protein assembly required for septum synthesis and cell separation. The Z ring exists at mid-cell during a major part of the cell cycle without contracting. Here, we show that MreB and FtsZ of Escherichia coli interact directly and that this interaction is required for Z ring contraction. We further show that the MreB-FtsZ interaction is required for transfer of cell-wall biosynthetic enzymes from the lateral to the mature divisome, allowing cells to synthesise the septum. Our observations show that bacterial cell division is coupled to cell elongation via a direct and essential interaction between FtsZ and MreB.
Structure of the Z Ring-associated Protein, ZapD, Bound to the C-terminal Domain of the Tubulin-like Protein, FtsZ, Suggests Mechanism of Z Ring Stabilization through FtsZ Cross-linking.

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Schumacher, Maria A; Huang, Kuo-Hsiang; Zeng, Wenjie; Janakiraman, Anuradha

2017-03-03

Cell division in most bacteria is mediated by the tubulin-like FtsZ protein, which polymerizes in a GTP-dependent manner to form the cytokinetic Z ring. A diverse repertoire of FtsZ-binding proteins affects FtsZ localization and polymerization to ensure correct Z ring formation. Many of these proteins bind the C-terminal domain (CTD) of FtsZ, which serves as a hub for FtsZ regulation. FtsZ ring-associated proteins, ZapA-D (Zaps), are important FtsZ regulatory proteins that stabilize FtsZ assembly and enhance Z ring formation by increasing lateral assembly of FtsZ protofilaments, which then form the Z ring. There are no structures of a Zap protein bound to FtsZ; therefore, how these proteins affect FtsZ polymerization has been unclear. Recent data showed ZapD binds specifically to the FtsZ CTD. Thus, to obtain insight into the ZapD-CTD interaction and how it may mediate FtsZ protofilament assembly, we determined the Escherichia coli ZapD-FtsZ CTD structure to 2.67 Å resolution. The structure shows that the CTD docks within a hydrophobic cleft in the ZapD helical domain and adopts an unusual structure composed of two turns of helix separated by a proline kink. FtsZ CTD residue Phe-377 inserts into the ZapD pocket, anchoring the CTD in place and permitting hydrophobic contacts between FtsZ residues Ile-374, Pro-375, and Leu-378 with ZapD residues Leu-74, Trp-77, Leu-91, and Leu-174. The structural findings were supported by mutagenesis coupled with biochemical and in vivo studies. The combined data suggest that ZapD acts as a molecular cross-linking reagent between FtsZ protofilaments to enhance FtsZ assembly. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.
YeeV is an Escherichia coli toxin that inhibits cell division by targeting the cytoskeleton proteins, FtsZ and MreB.

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Tan, Qian; Awano, Naoki; Inouye, Masayori

2011-01-01

Toxin-antitoxin (TA) systems of free-living bacteria have recently demonstrated that these toxins inhibit cell growth by targeting essential functions of cellular metabolism. Here we show that YeeV toxin inhibits cell division, leads to a change in morphology and lysis of Escherichia coli cells. YeeV interacts with two essential cytoskeleton proteins, FtsZ and MreB. Purified YeeV inhibits both the GTPase activity and the GTP-dependent polymerization of FtsZ. YeeV also inhibits ATP-dependent polymerization of MreB. Truncated C-terminal deletions of YeeV result in elongation of cells, and a deletion of the first 15 amino acids from the N-terminus of YeeV caused lemon-shaped cell formation. The YeeV toxin is distinct from other well-studied toxins: it directs the binding of two cytoskeletal proteins and inhibits FtsZ and MreB simultaneously. © 2010 Blackwell Publishing Ltd.
Bacillus subtilis SepF binds to the C-terminus of FtsZ.

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Król, Ewa; van Kessel, Sebastiaan P; van Bezouwen, Laura S; Kumar, Neeraj; Boekema, Egbert J; Scheffers, Dirk-Jan

2012-01-01

Bacterial cell division is mediated by a multi-protein machine known as the "divisome", which assembles at the site of cell division. Formation of the divisome starts with the polymerization of the tubulin-like protein FtsZ into a ring, the Z-ring. Z-ring formation is under tight control to ensure bacteria divide at the right time and place. Several proteins bind to the Z-ring to mediate its membrane association and persistence throughout the division process. A conserved stretch of amino acids at the C-terminus of FtsZ appears to be involved in many interactions with other proteins. Here, we describe a novel pull-down assay to look for binding partners of the FtsZ C-terminus, using a HaloTag affinity tag fused to the C-terminal 69 amino acids of B. subtilis FtsZ. Using lysates of Escherichia coli overexpressing several B. subtilis cell division proteins as prey we show that the FtsZ C-terminus specifically pulls down SepF, but not EzrA or MinC, and that the interaction depends on a conserved 16 amino acid stretch at the extreme C-terminus. In a reverse pull-down SepF binds to full-length FtsZ but not to a FtsZΔC16 truncate or FtsZ with a mutation of a conserved proline in the C-terminus. We show that the FtsZ C-terminus is required for the formation of tubules from FtsZ polymers by SepF rings. An alanine-scan of the conserved 16 amino acid stretch shows that many mutations affect SepF binding. Combined with the observation that SepF also interacts with the C-terminus of E. coli FtsZ, which is not an in vivo binding partner, we propose that the secondary and tertiary structure of the FtsZ C-terminus, rather than specific amino acids, are recognized by SepF.
Bacillus subtilis SepF binds to the C-terminus of FtsZ.

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Ewa Król

Full Text Available Bacterial cell division is mediated by a multi-protein machine known as the "divisome", which assembles at the site of cell division. Formation of the divisome starts with the polymerization of the tubulin-like protein FtsZ into a ring, the Z-ring. Z-ring formation is under tight control to ensure bacteria divide at the right time and place. Several proteins bind to the Z-ring to mediate its membrane association and persistence throughout the division process. A conserved stretch of amino acids at the C-terminus of FtsZ appears to be involved in many interactions with other proteins. Here, we describe a novel pull-down assay to look for binding partners of the FtsZ C-terminus, using a HaloTag affinity tag fused to the C-terminal 69 amino acids of B. subtilis FtsZ. Using lysates of Escherichia coli overexpressing several B. subtilis cell division proteins as prey we show that the FtsZ C-terminus specifically pulls down SepF, but not EzrA or MinC, and that the interaction depends on a conserved 16 amino acid stretch at the extreme C-terminus. In a reverse pull-down SepF binds to full-length FtsZ but not to a FtsZΔC16 truncate or FtsZ with a mutation of a conserved proline in the C-terminus. We show that the FtsZ C-terminus is required for the formation of tubules from FtsZ polymers by SepF rings. An alanine-scan of the conserved 16 amino acid stretch shows that many mutations affect SepF binding. Combined with the observation that SepF also interacts with the C-terminus of E. coli FtsZ, which is not an in vivo binding partner, we propose that the secondary and tertiary structure of the FtsZ C-terminus, rather than specific amino acids, are recognized by SepF.
YeeU enhances the bundling of cytoskeletal polymers of MreB and FtsZ, antagonizing the CbtA (YeeV) toxicity in Escherichia coli.

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Masuda, Hisako; Tan, Qian; Awano, Naoki; Wu, Kuen-Phon; Inouye, Masayori

2012-06-01

All free-living bacteria carry the toxin-antitoxin (TA) systems controlling cell growth and death under stress conditions. YeeU-YeeV (CbtA) is one of the Escherichia coli TA systems, and the toxin, CbtA, has been reported to inhibit the polymerization of bacterial cytoskeletal proteins, MreB and FtsZ. Here, we demonstrate that the antitoxin, YeeU, is a novel type of antitoxin (type IV TA system), which does not form a complex with CbtA but functions as an antagonist for CbtA toxicity. Specifically, YeeU was found to directly interact with MreB and FtsZ, and enhance the bundling of their filamentous polymers in vitro. Surprisingly, YeeU neutralized not only the toxicity of CbtA but also the toxicity caused by other inhibitors of MreB and FtsZ, such as A22, SulA and MinC, indicating that YeeU-induced bundling of MreB and FtsZ has an intrinsic global stabilizing effect on their homeostasis. Here we propose to rename YeeU as CbeA for cytoskeleton bundling-enhancing factor A. © 2012 Blackwell Publishing Ltd.
CbtA toxin of Escherichia coli inhibits cell division and cell elongation via direct and independent interactions with FtsZ and MreB.

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Heller, Danielle M; Tavag, Mrinalini; Hochschild, Ann

2017-09-01

The toxin components of toxin-antitoxin modules, found in bacterial plasmids, phages, and chromosomes, typically target a single macromolecule to interfere with an essential cellular process. An apparent exception is the chromosomally encoded toxin component of the E. coli CbtA/CbeA toxin-antitoxin module, which can inhibit both cell division and cell elongation. A small protein of only 124 amino acids, CbtA, was previously proposed to interact with both FtsZ, a tubulin homolog that is essential for cell division, and MreB, an actin homolog that is essential for cell elongation. However, whether or not the toxic effects of CbtA are due to direct interactions with these predicted targets is not known. Here, we genetically separate the effects of CbtA on cell elongation and cell division, showing that CbtA interacts directly and independently with FtsZ and MreB. Using complementary genetic approaches, we identify the functionally relevant target surfaces on FtsZ and MreB, revealing that in both cases, CbtA binds to surfaces involved in essential cytoskeletal filament architecture. We show further that each interaction contributes independently to CbtA-mediated toxicity and that disruption of both interactions is required to alleviate the observed toxicity. Although several other protein modulators are known to target FtsZ, the CbtA-interacting surface we identify represents a novel inhibitory target. Our findings establish CbtA as a dual function toxin that inhibits both cell division and cell elongation via direct and independent interactions with FtsZ and MreB.
The pH dependence of polymerization and bundling by the essential bacterial cytoskeletal protein FtsZ.

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Raúl Pacheco-Gómez

Full Text Available There is a growing body of evidence that bacterial cell division is an intricate coordinated process of comparable complexity to that seen in eukaryotic cells. The dynamic assembly of Escherichia coli FtsZ in the presence of GTP is fundamental to its activity. FtsZ polymerization is a very attractive target for novel antibiotics given its fundamental and universal function. In this study our aim was to understand further the GTP-dependent FtsZ polymerization mechanism and our main focus is on the pH dependence of its behaviour. A key feature of this work is the use of linear dichroism (LD to follow the polymerization of FtsZ monomers into polymeric structures. LD is the differential absorption of light polarized parallel and perpendicular to an orientation direction (in this case that provided by shear flow. It thus readily distinguishes between FtsZ polymers and monomers. It also distinguishes FtsZ polymers and less well-defined aggregates, which light scattering methodologies do not. The polymerization of FtsZ over a range of pHs was studied by right-angled light scattering to probe mass of FtsZ structures, LD to probe real-time formation of linear polymeric fibres, a specially developed phosphate release assay to relate guanosine triphosphate (GTP hydrolysis to polymer formation, and electron microscopy (EM imaging of reaction products as a function of time and pH. We have found that lowering the pH from neutral to 6.5 does not change the nature of the FtsZ polymers in solution--it simply facilitates the polymerization so the fibres present are longer and more abundant. Conversely, lowering the pH to 6.0 has much the same effect as introducing divalent cations or the FtsZ-associated protein YgfE (a putative ZapA orthologue in E. coli--it stabilizes associations of protofilaments.
A specific role for the ZipA protein in cell division: stabilization of the FtsZ protein.

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Pazos, Manuel; Natale, Paolo; Vicente, Miguel

2013-02-01

In Escherichia coli, the cell division protein FtsZ is anchored to the cytoplasmic membrane by the action of the bitopic membrane protein ZipA and the cytoplasmic protein FtsA. Although the presence of both ZipA and FtsA is strictly indispensable for cell division, an FtsA gain-of-function mutant FtsA* (R286W) can bypass the ZipA requirement for cell division. This observation casts doubts on the role of ZipA and its need for cell division. Maxicells are nucleoid-free bacterial cells used as a whole cell in vitro system to probe protein-protein interactions without the need of protein purification. We show that ZipA protects FtsZ from the ClpXP-directed degradation observed in E. coli maxicells and that ZipA-stabilized FtsZ forms membrane-attached spiral-like structures in the bacterial cytoplasm. The overproduction of the FtsZ-binding ZipA domain is sufficient to protect FtsZ from degradation, whereas other C-terminal ZipA partial deletions lacking it are not. Individual overproduction of the proto-ring component FtsA or its gain-of-function mutant FtsA* does not result in FtsZ protection. Overproduction of FtsA or FtsA* together with ZipA does not interfere with the FtsZ protection. Moreover, neither FtsA nor FtsA* protects FtsZ when overproduced together with ZipA mutants lacking the FZB domain. We propose that ZipA protects FtsZ from degradation by ClpP by making the FtsZ site of interaction unavailable to the ClpX moiety of the ClpXP protease. This role cannot be replaced by either FtsA or FtsA*, suggesting a unique function for ZipA in proto-ring stability.
ZipA binds to FtsZ with high affinity and enhances the stability of FtsZ protofilaments.

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Anuradha Kuchibhatla

Full Text Available A bacterial membrane protein ZipA that tethers FtsZ to the membrane is known to promote FtsZ assembly. In this study, the binding of ZipA to FtsZ was monitored using fluorescence spectroscopy. ZipA was found to bind to FtsZ with high affinities at three different (6.0, 6.8 and 8.0 pHs, albeit the binding affinity decreased with increasing pH. Further, thick bundles of FtsZ protofilaments were observed in the presence of ZipA under the pH conditions used in this study indicating that ZipA can promote FtsZ assembly and stabilize FtsZ polymers under unfavorable conditions. Bis-ANS, a hydrophobic probe, decreased the interaction of FtsZ and ZipA indicating that the interaction between FtsZ and ZipA is hydrophobic in nature. ZipA prevented the dilution induced disassembly of FtsZ polymers suggesting that it stabilizes FtsZ protofilaments. Fluorescein isothiocyanate-labeled ZipA was found to be uniformly distributed along the length of the FtsZ protofilaments indicating that ZipA stabilizes FtsZ protofilaments by cross-linking them.
A Polymerization-Associated Structural Switch in FtsZ That Enables Treadmilling of Model Filaments

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James M. Wagstaff

2017-05-01

Full Text Available Bacterial cell division in many organisms involves a constricting cytokinetic ring that is orchestrated by the tubulin-like protein FtsZ. FtsZ forms dynamic filaments close to the membrane at the site of division that have recently been shown to treadmill around the division ring, guiding septal wall synthesis. Here, using X-ray crystallography of Staphylococcus aureus FtsZ (SaFtsZ, we reveal how an FtsZ can adopt two functionally distinct conformations, open and closed. The open form is found in SaFtsZ filaments formed in crystals and also in soluble filaments of Escherichia coli FtsZ as deduced by electron cryomicroscopy. The closed form is found within several crystal forms of two nonpolymerizing SaFtsZ mutants and corresponds to many previous FtsZ structures from other organisms. We argue that FtsZ’s conformational switch is polymerization-associated, driven by the formation of the longitudinal intersubunit interfaces along the filament. We show that such a switch provides explanations for both how treadmilling may occur within a single-stranded filament and why filament assembly is cooperative.
NDK Interacts with FtsZ and Converts GDP to GTP to Trigger FtsZ Polymerisation--A Novel Role for NDK.

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Mishra, Saurabh; Jakkala, Kishor; Srinivasan, Ramanujam; Arumugam, Muthu; Ranjeri, Raghavendra; Gupta, Prabuddha; Rajeswari, Haryadi; Ajitkumar, Parthasarathi

2015-01-01

Nucleoside diphosphate kinase (NDK), conserved across bacteria to humans, synthesises NTP from NDP and ATP. The eukaryotic homologue, the NDPK, uses ATP to phosphorylate the tubulin-bound GDP to GTP for tubulin polymerisation. The bacterial cytokinetic protein FtsZ, which is the tubulin homologue, also uses GTP for polymerisation. Therefore, we examined whether NDK can interact with FtsZ to convert FtsZ-bound GDP and/or free GDP to GTP to trigger FtsZ polymerisation. Recombinant and native NDK and FtsZ proteins of Mycobacterium smegmatis and Mycobacterium tuberculosis were used as the experimental samples. FtsZ polymersation was monitored using 90° light scattering and FtsZ polymer pelleting assays. The γ32P-GTP synthesised by NDK from GDP and γ32P-ATP was detected using thin layer chromatography and quantitated using phosphorimager. The FtsZ bound 32P-GTP was quantitated using phosphorimager, after UV-crosslinking, followed by SDS-PAGE. The NDK-FtsZ interaction was determined using Ni2+-NTA-pulldown assay and co-immunoprecipitation of the recombinant and native proteins in vitro and ex vivo, respectively. NDK triggered instantaneous polymerisation of GDP-precharged recombinant FtsZ in the presence of ATP, similar to the polymerisation of recombinant FtsZ (not GDP-precharged) upon the direct addition of GTP. Similarly, NDK triggered polymerisation of recombinant FtsZ (not GDP-precharged) in the presence of free GDP and ATP as well. Mutant NDK, partially deficient in GTP synthesis from ATP and GDP, triggered low level of polymerisation of MsFtsZ, but not of MtFtsZ. As characteristic of NDK's NTP substrate non-specificity, it used CTP, TTP, and UTP also to convert GDP to GTP, to trigger FtsZ polymerisation. The NDK of one mycobacterial species could trigger the polymerisation of the FtsZ of another mycobacterial species. Both the recombinant and the native NDK and FtsZ showed interaction with each other in vitro and ex vivo, alluding to the possibility of direct
NDK Interacts with FtsZ and Converts GDP to GTP to Trigger FtsZ Polymerisation - A Novel Role for NDK

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Mishra, Saurabh; Jakkala, Kishor; Srinivasan, Ramanujam; Arumugam, Muthu; Ranjeri, Raghavendra; Gupta, Prabuddha; Rajeswari, Haryadi; Ajitkumar, Parthasarathi

2015-01-01

Introduction Nucleoside diphosphate kinase (NDK), conserved across bacteria to humans, synthesises NTP from NDP and ATP. The eukaryotic homologue, the NDPK, uses ATP to phosphorylate the tubulin-bound GDP to GTP for tubulin polymerisation. The bacterial cytokinetic protein FtsZ, which is the tubulin homologue, also uses GTP for polymerisation. Therefore, we examined whether NDK can interact with FtsZ to convert FtsZ-bound GDP and/or free GDP to GTP to trigger FtsZ polymerisation. Methods Recombinant and native NDK and FtsZ proteins of Mycobacterium smegmatis and Mycobacterium tuberculosis were used as the experimental samples. FtsZ polymersation was monitored using 90° light scattering and FtsZ polymer pelleting assays. The γ32P-GTP synthesised by NDK from GDP and γ32P-ATP was detected using thin layer chromatography and quantitated using phosphorimager. The FtsZ bound 32P-GTP was quantitated using phosphorimager, after UV-crosslinking, followed by SDS-PAGE. The NDK-FtsZ interaction was determined using Ni2+-NTA-pulldown assay and co-immunoprecipitation of the recombinant and native proteins in vitro and ex vivo, respectively. Results NDK triggered instantaneous polymerisation of GDP-precharged recombinant FtsZ in the presence of ATP, similar to the polymerisation of recombinant FtsZ (not GDP-precharged) upon the direct addition of GTP. Similarly, NDK triggered polymerisation of recombinant FtsZ (not GDP-precharged) in the presence of free GDP and ATP as well. Mutant NDK, partially deficient in GTP synthesis from ATP and GDP, triggered low level of polymerisation of MsFtsZ, but not of MtFtsZ. As characteristic of NDK’s NTP substrate non-specificity, it used CTP, TTP, and UTP also to convert GDP to GTP, to trigger FtsZ polymerisation. The NDK of one mycobacterial species could trigger the polymerisation of the FtsZ of another mycobacterial species. Both the recombinant and the native NDK and FtsZ showed interaction with each other in vitro and ex vivo, alluding
Thermal adaptation of mesophilic and thermophilic FtsZ assembly by modulation of the critical concentration.

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Luis Concha-Marambio

Full Text Available Cytokinesis is the last stage in the cell cycle. In prokaryotes, the protein FtsZ guides cell constriction by assembling into a contractile ring-shaped structure termed the Z-ring. Constriction of the Z-ring is driven by the GTPase activity of FtsZ that overcomes the energetic barrier between two protein conformations having different propensities to assemble into polymers. FtsZ is found in psychrophilic, mesophilic and thermophilic organisms thereby functioning at temperatures ranging from subzero to >100°C. To gain insight into the functional adaptations enabling assembly of FtsZ in distinct environmental conditions, we analyzed the energetics of FtsZ function from mesophilic Escherichia coli in comparison with FtsZ from thermophilic Methanocaldococcus jannaschii. Presumably, the assembly may be similarly modulated by temperature for both FtsZ orthologs. The temperature dependence of the first-order rates of nucleotide hydrolysis and of polymer disassembly, indicated an entropy-driven destabilization of the FtsZ-GTP intermediate. This destabilization was true for both mesophilic and thermophilic FtsZ, reflecting a conserved mechanism of disassembly. From the temperature dependence of the critical concentrations for polymerization, we detected a change of opposite sign in the heat capacity, that was partially explained by the specific changes in the solvent-accessible surface area between the free and polymerized states of FtsZ. At the physiological temperature, the assembly of both FtsZ orthologs was found to be driven by a small positive entropy. In contrast, the assembly occurred with a negative enthalpy for mesophilic FtsZ and with a positive enthalpy for thermophilic FtsZ. Notably, the assembly of both FtsZ orthologs is characterized by a critical concentration of similar value (1-2 μM at the environmental temperatures of their host organisms. These findings suggest a simple but robust mechanism of adaptation of FtsZ, previously shown
The Antibacterial Cell Division Inhibitor PC190723 Is an FtsZ Polymer-stabilizing Agent That Induces Filament Assembly and Condensation*

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Andreu, José M.; Schaffner-Barbero, Claudia; Huecas, Sonia; Alonso, Dulce; Lopez-Rodriguez, María L.; Ruiz-Avila, Laura B.; Núñez-Ramírez, Rafael; Llorca, Oscar; Martín-Galiano, Antonio J.

2010-01-01

Cell division protein FtsZ can form single-stranded filaments with a cooperative behavior by self-switching assembly. Subsequent condensation and bending of FtsZ filaments are important for the formation and constriction of the cytokinetic ring. PC190723 is an effective bactericidal cell division inhibitor that targets FtsZ in the pathogen Staphylococcus aureus and Bacillus subtilis and does not affect Escherichia coli cells, which apparently binds to a zone equivalent to the binding site of ...
Cytological profile of antibacterial FtsZ inhibitors and synthetic peptide MciZ

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Lidia Araujo-Bazan

2016-10-01

Full Text Available Cell division protein FtsZ is the organizer of the cytokinetic ring in almost all bacteria and a target for the discovery of new antibacterial agents that are needed to counter widespread antibiotic resistance. Bacterial cytological profiling, using quantitative microscopy, is a powerful approach for identifying the mechanism of action of antibacterial molecules affecting different cellular pathways. We have determined the cytological profile on Bacillus subtilis cells of a selection of small molecule inhibitors targeting FtsZ on different binding sites. FtsZ inhibitors lead to long undivided cells, impair the normal assembly of FtsZ into the midcell Z-rings, induce aberrant ring distributions, punctate FtsZ foci, membrane spots and also modify nucleoid length. Quantitative analysis of cell and nucleoid length combined, or the Z-ring distribution, allows categorizing FtsZ inhibitors and to distinguish them from antibiotics with other mechanisms of action, which should be useful for identifying new antibacterial FtsZ inhibitors. Biochemical assays of FtsZ polymerization and GTPase activity combined explain the cellular effects of the FtsZ polymer stabilizing agent PC190723 and its fragments. MciZ is a 40-aminoacid endogenous inhibitor of cell division normally expressed during sporulation in B. subtilis. Using FtsZ cytological profiling we have determined that exogenous synthetic MciZ is an effective inhibitor of B. subtilis cell division, Z-ring formation and localization. This finding supports our cell-based approach to screen for FtsZ inhibitors and opens new possibilities for peptide inhibitors of bacterial cell division.

A novel membrane-bound toxin for cell division, CptA (YgfX), inhibits polymerization of cytoskeleton proteins, FtsZ and MreB, in Escherichia coli.

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Masuda, Hisako; Tan, Qian; Awano, Naoki; Yamaguchi, Yoshihiro; Inouye, Masayori

2012-03-01

Nearly all free-living bacteria carry toxin-antitoxin (TA) systems on their genomes, through which cell growth and death are regulated. Toxins target a variety of essential cellular functions, including DNA replication, translation, and cell division. Here, we identified a novel toxin, YgfX, on the Escherichia coli genome. The toxin, consisting of 135 residues, is composed of the N-terminal membrane domain, which encompasses two transmembrane segments, and the C-terminal cytoplasmic domain. Upon YgfX expression, the cells were initially elongated and then the middle portion of the cells became inflated to form a lemon shape. YgfX was found to interact with MreB and FtsZ, two essential cytoskeletal proteins in E. coli. The cytoplasmic domain [YgfX(C)] was found to be responsible for the YgfX toxicity, as purified YgfX(C) was found to block the polymerization of FtsZ and MreB in vitro. YgfY, located immediately upstream of YgfX, was shown to be the cognate antitoxin; notably, YgfX is the first membrane-associating toxin in bacterial TA systems. We propose to rename the toxin and the antitoxin as CptA and CptB (for Cytoskeleton Polymerization inhibiting Toxin), respectively. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.
Determination of transcriptional units and gene products from the ftsA region of Escherichia coli.

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Lutkenhaus, J F; Wu, H C

1980-01-01

Lambda transducing phage gamma 16-2 carries the genes envA, ftsZ, ftsA, ddl, and murC and directs the synthesis of six unique proteins in ultraviolet-irradiated cells. Various derivatives of gamma 16-2 carrying smaller segments of the bacterial deoxyribonucleic acid have also been analyzed for their capacity to direct protein synthesis in ultraviolet-irradiated cells. These results, in combination with genetic results, have allowed the gene product of each of these genes to be assigned. In addition, an unidentified gene was located counterclockwise to murC between murC and murF. Analysis of the direction of transcription indicates that murC, ddl, ftsA, and ftsZ are transcribed clockwise on the Escherichia coli genetic map, and envA is transcribed counterclockwise. In addition, it is shown that each of the genes envA, ftsZ, and ftsA can be expressed independently. Images PMID:6447690
FtsZ Polymerization Assays : Simple Protocols and Considerations

NARCIS (Netherlands)

Król, Ewa; Scheffers, Dirk-Jan

2013-01-01

During bacterial cell division, the essential protein FtsZ assembles in the middle of the cell to form the so-called Z-ring. FtsZ polymerizes into long filaments in the presence of GTP in vitro, and polymerization is regulated by several accessory proteins. FtsZ polymerization has been extensively
Macromolecular interactions of the bacterial division FtsZ protein: from quantitative biochemistry and crowding to reconstructing minimal divisomes in the test tube.

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Rivas, Germán; Alfonso, Carlos; Jiménez, Mercedes; Monterroso, Begoña; Zorrilla, Silvia

2013-06-01

The division of Escherichia coli is an essential process strictly regulated in time and space. It requires the association of FtsZ with other proteins to assemble a dynamic ring during septation, forming part of the functionally active division machinery, the divisome. FtsZ reversibly interacts with FtsA and ZipA at the cytoplasmic membrane to form a proto-ring, the first molecular assembly of the divisome, which is ultimately joined by the rest of the division-specific proteins. In this review we summarize the quantitative approaches used to study the activity, interactions, and assembly properties of FtsZ under well-defined solution conditions, with the aim of furthering our understanding of how the behavior of FtsZ is controlled by nucleotides and physiological ligands. The modulation of the association and assembly properties of FtsZ by excluded-volume effects, reproducing in part the natural crowded environment in which this protein has evolved to function, will be described. The subsequent studies on the reactivity of FtsZ in membrane-like systems using biochemical, biophysical, and imaging technologies are reported. Finally, we discuss the experimental challenges to be met to achieve construction of the minimum protein set needed to initiate bacterial division, without cells, in a cell-like compartment. This integrated approach, combining quantitative and synthetic strategies, will help to support (or dismiss) conclusions already derived from cellular and molecular analysis and to complete our understanding on how bacterial division works.
Effects of rhodomyrtone on Gram-positive bacterial tubulin homologue FtsZ

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Dennapa Saeloh

2017-02-01

Full Text Available Rhodomyrtone, a natural antimicrobial compound, displays potent activity against many Gram-positive pathogenic bacteria, comparable to last-defence antibiotics including vancomycin and daptomycin. Our previous studies pointed towards effects of rhodomyrtone on the bacterial membrane and cell wall. In addition, a recent molecular docking study suggested that the compound could competitively bind to the main bacterial cell division protein FtsZ. In this study, we applied a computational approach (in silico, in vitro, and in vivo experiments to investigate molecular interactions of rhodomyrtone with FtsZ. Using molecular simulation, FtsZ conformational changes were observed in both (S- and (R-rhodomyrtone binding states, compared with the three natural states of FtsZ (ligand-free, GDP-, and GTP-binding states. Calculations of free binding energy showed a higher affinity of FtsZ to (S-rhodomyrtone (−35.92 ± 0.36 kcal mol−1 than the GDP substrate (−23.47 ± 0.25 kcal mol−1 while less affinity was observed in the case of (R-rhodomyrtone (−18.11 ± 0.11 kcal mol−1. In vitro experiments further revealed that rhodomyrtone reduced FtsZ polymerization by 36% and inhibited GTPase activity by up to 45%. However, the compound had no effect on FtsZ localization in Bacillus subtilis at inhibitory concentrations and cells also did not elongate after treatment. Higher concentrations of rhodomyrtone did affect localization of FtsZ and also affected localization of its membrane anchor proteins FtsA and SepF, showing that the compound did not specifically inhibit FtsZ but rather impaired multiple divisome proteins. Furthermore, a number of cells adopted a bean-like shape suggesting that rhodomyrtone possibly possesses further targets involved in cell envelope synthesis and/or maintenance.
Structural insights of Staphylococcus aureus FtsZ inhibitors through molecular docking, 3D-QSAR and molecular dynamics simulations.

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Ballu, Srilata; Itteboina, Ramesh; Sivan, Sree Kanth; Manga, Vijjulatha

2018-02-01

Filamentous temperature-sensitive protein Z (FtsZ) is a protein encoded by the FtsZ gene that assembles into a Z-ring at the future site of the septum of bacterial cell division. Structurally, FtsZ is a homolog of eukaryotic tubulin but has low sequence similarity; this makes it possible to obtain FtsZ inhibitors without affecting the eukaryotic cell division. Computational studies were performed on a series of substituted 3-arylalkoxybenzamide derivatives reported as inhibitors of FtsZ activity in Staphylococcus aureus. Quantitative structure-activity relationship models (QSAR) models generated showed good statistical reliability, which is evident from r 2 ncv and r 2 loo values. The predictive ability of these models was determined and an acceptable predictive correlation (r 2 Pred ) values were obtained. Finally, we performed molecular dynamics simulations in order to examine the stability of protein-ligand interactions. This facilitated us to compare free binding energies of cocrystal ligand and newly designed molecule B1. The good concordance between the docking results and comparative molecular field analysis (CoMFA)/comparative molecular similarity indices analysis (CoMSIA) contour maps afforded obliging clues for the rational modification of molecules to design more potent FtsZ inhibitors.
FtsZ from radiation resistant bacterium Deinococcus radiodurans is different from its characterized homologues

International Nuclear Information System (INIS)

Mehta, Kruti P.; Misra, H.S.

2012-01-01

Polymerization/depolymerization dynamics of FtsZ and its GTPase activity are interdependent and the regulation of these processes determines the growth rate in a bacterium. Deinococcus radiodurans R1 that is best known for its extraordinary radiation resistance and efficient DNA double strand break repair is a comparatively slow growing bacterium and its growth gets arrested in response to gamma radiation. Mechanisms of cell division and its regulation under gamma stressed growth condition would be worth investigating. Genome of this bacterium encodes at least all the known components of divisome. Recombinant FtsZ of D. radiodurans (drFtsZ) preferred Mg 2+ for its GTPase activity. Relatively a very low GTPase activity was observed in presence of Mn 2+ , Co 2+ and Ni 2+ while release of inorganic phosphate could not be detected in presence of other divalent ions including Ca 2+ . GTPase activity of drFtsZ was lower than E. coli but higher than Mycobacterium and it required both Mg 2+ and GTP for its polymerization. Its GTPase activity did not increase with increasing concentration of Mg 2+ and correlates with the bundling of protofilaments. Results obtained from transmission electron microscopy and sedimentation analysis supported the reciprocal correlation of polymerization/depolymerization with the levels of GTPase activity. Dynamic light scattering in presence of 5mM or higher concentration of Mg 2+ and Mn 2 showed a characteristic cyclic change in light scattering without addition of extra metal ion or GTP
The Antibacterial Cell Division Inhibitor PC190723 Is an FtsZ Polymer-stabilizing Agent That Induces Filament Assembly and Condensation*

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Andreu, José M.; Schaffner-Barbero, Claudia; Huecas, Sonia; Alonso, Dulce; Lopez-Rodriguez, María L.; Ruiz-Avila, Laura B.; Núñez-Ramírez, Rafael; Llorca, Oscar; Martín-Galiano, Antonio J.

2010-01-01

Cell division protein FtsZ can form single-stranded filaments with a cooperative behavior by self-switching assembly. Subsequent condensation and bending of FtsZ filaments are important for the formation and constriction of the cytokinetic ring. PC190723 is an effective bactericidal cell division inhibitor that targets FtsZ in the pathogen Staphylococcus aureus and Bacillus subtilis and does not affect Escherichia coli cells, which apparently binds to a zone equivalent to the binding site of the antitumor drug taxol in tubulin (Haydon, D. J., Stokes, N. R., Ure, R., Galbraith, G., Bennett, J. M., Brown, D. R., Baker, P. J., Barynin, V. V., Rice, D. W., Sedelnikova, S. E., Heal, J. R., Sheridan, J. M., Aiwale, S. T., Chauhan, P. K., Srivastava, A., Taneja, A., Collins, I., Errington, J., and Czaplewski, L. G. (2008) Science 312, 1673–1675). We have found that the benzamide derivative PC190723 is an FtsZ polymer-stabilizing agent. PC190723 induced nucleated assembly of Bs-FtsZ into single-stranded coiled protofilaments and polymorphic condensates, including bundles, coils, and toroids, whose formation could be modulated with different solution conditions. Under conditions for reversible assembly of Bs-FtsZ, PC190723 binding reduced the GTPase activity and induced the formation of straight bundles and ribbons, which was also observed with Sa-FtsZ but not with nonsusceptible Ec-FtsZ. The fragment 2,6-difluoro-3-methoxybenzamide also induced Bs-FtsZ bundling. We propose that polymer stabilization by PC190723 suppresses in vivo FtsZ polymer dynamics and bacterial division. The biochemical action of PC190723 on FtsZ parallels that of the microtubule-stabilizing agent taxol on the eukaryotic structural homologue tubulin. Both taxol and PC190723 stabilize polymers against disassembly by preferential binding to each assembled protein. It is yet to be investigated whether both ligands target structurally related assembly switches. PMID:20212044
Interactions among the early Escherichia coli divisome proteins revealed by bimolecular fluorescence complementation.

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Pazos, Manuel; Natale, Paolo; Margolin, William; Vicente, Miguel

2013-12-01

We used bimolecular fluorescence complementation (BiFC) assays to detect protein-protein interactions of all possible pairs of the essential Escherichia coli proto-ring components, FtsZ, FtsA and ZipA, as well as the non-essential FtsZ-associated proteins ZapA and ZapB. We found an unexpected interaction between ZipA and ZapB at potential cell division sites, and when co-overproduced, they induced long narrow constrictions at division sites that were dependent on FtsZ. These assays also uncovered an interaction between ZipA and ZapA that was mediated by FtsZ. BiFC with ZapA and ZapB showed that in addition to their expected interaction at midcell, they also interact at the cell poles. BiFC detected interaction between FtsZ and ZapB at midcell and close to the poles. Results from the remaining pairwise combinations confirmed known interactions between FtsZ and ZipA, and ZapB with itself. © 2013 Society for Applied Microbiology and John Wiley & Sons Ltd.
Novel trisubstituted benzimidazoles, targeting Mtb FtsZ, as a new class of antitubercular agents.

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Kumar, Kunal; Awasthi, Divya; Lee, Seung-Yub; Zanardi, Ilaria; Ruzsicska, Bela; Knudson, Susan; Tonge, Peter J; Slayden, Richard A; Ojima, Iwao

2011-01-13

Libraries of novel trisubstituted benzimidazoles were created through rational drug design. A good number of these benzimidazoles exhibited promising MIC values in the range of 0.5-6 μg/mL (2-15 μM) for their antibacterial activity against Mtb H37Rv strain. Moreover, five of the lead compounds also exhibited excellent activity against clinical Mtb strains with different drug-resistance profiles. All lead compounds did not show appreciable cytotoxicity (IC(50) > 200 μM) against Vero cells, which inhibited Mtb FtsZ assembly in a dose dependent manner. The two lead compounds unexpectedly showed enhancement of the GTPase activity of Mtb FtsZ. The result strongly suggests that the increased GTPase activity destabilizes FtsZ assembly, leading to efficient inhibition of FtsZ polymerization and filament formation. The TEM and SEM analyses of Mtb FtsZ and Mtb cells, respectively, treated with a lead compound strongly suggest that lead benzimidazoles have a novel mechanism of action on the inhibition of Mtb FtsZ assembly and Z-ring formation.
Cytoplasmic Domain of MscS Interacts with Cell Division Protein FtsZ: A Possible Non-Channel Function of the Mechanosensitive Channel in Escherichia Coli.

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Piotr Koprowski

Full Text Available Bacterial mechano-sensitive (MS channels reside in the inner membrane and are considered to act as emergency valves whose role is to lower cell turgor when bacteria enter hypo-osmotic environments. However, there is emerging evidence that members of the Mechano-sensitive channel Small (MscS family play additional roles in bacterial and plant cell physiology. MscS has a large cytoplasmic C-terminal region that changes its shape upon activation and inactivation of the channel. Our pull-down and co-sedimentation assays show that this domain interacts with FtsZ, a bacterial tubulin-like protein. We identify point mutations in the MscS C-terminal domain that reduce binding to FtsZ and show that bacteria expressing these mutants are compromised in growth on sublethal concentrations of β-lactam antibiotics. Our results suggest that interaction between MscS and FtsZ could occur upon inactivation and/or opening of the channel and could be important for the bacterial cell response against sustained stress upon stationary phase and in the presence of β-lactam antibiotics.
Cytoplasmic Domain of MscS Interacts with Cell Division Protein FtsZ: A Possible Non-Channel Function of the Mechanosensitive Channel in Escherichia Coli.

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Koprowski, Piotr; Grajkowski, Wojciech; Balcerzak, Marcin; Filipiuk, Iwona; Fabczak, Hanna; Kubalski, Andrzej

2015-01-01

Bacterial mechano-sensitive (MS) channels reside in the inner membrane and are considered to act as emergency valves whose role is to lower cell turgor when bacteria enter hypo-osmotic environments. However, there is emerging evidence that members of the Mechano-sensitive channel Small (MscS) family play additional roles in bacterial and plant cell physiology. MscS has a large cytoplasmic C-terminal region that changes its shape upon activation and inactivation of the channel. Our pull-down and co-sedimentation assays show that this domain interacts with FtsZ, a bacterial tubulin-like protein. We identify point mutations in the MscS C-terminal domain that reduce binding to FtsZ and show that bacteria expressing these mutants are compromised in growth on sublethal concentrations of β-lactam antibiotics. Our results suggest that interaction between MscS and FtsZ could occur upon inactivation and/or opening of the channel and could be important for the bacterial cell response against sustained stress upon stationary phase and in the presence of β-lactam antibiotics.
Targeting the Wolbachia cell division protein FtsZ as a new approach for antifilarial therapy.

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Zhiru Li

2011-11-01

Full Text Available The use of antibiotics targeting the obligate bacterial endosymbiont Wolbachia of filarial parasites has been validated as an approach for controlling filarial infection in animals and humans. Availability of genomic sequences for the Wolbachia (wBm present in the human filarial parasite Brugia malayi has enabled genome-wide searching for new potential drug targets. In the present study, we investigated the cell division machinery of wBm and determined that it possesses the essential cell division gene ftsZ which was expressed in all developmental stages of B. malayi examined. FtsZ is a GTPase thereby making the protein an attractive Wolbachia drug target. We described the molecular characterization and catalytic properties of Wolbachia FtsZ. We also demonstrated that the GTPase activity was inhibited by the natural product, berberine, and small molecule inhibitors identified from a high-throughput screen. Furthermore, berberine was also effective in reducing motility and reproduction in B. malayi parasites in vitro. Our results should facilitate the discovery of selective inhibitors of FtsZ as a novel anti-symbiotic approach for controlling filarial infection. NOTE: The nucleotide sequences reported in this paper are available in GenBank™ Data Bank under the accession number wAlB-FtsZ (JN616286.
The Chloroplast Division Protein ARC6 Acts to Inhibit Disassembly of GDP-bound FtsZ2.

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Sung, Min Woo; Shaik, Rahamthulla; TerBush, Allan D; Osteryoung, Katherine W; Vitha, Stanislav; Holzenburg, Andreas

2018-05-16

Chloroplasts host photosynthesis and fulfill other metabolic functions that are essential to plant life. They have to divide by binary fission to maintain their numbers throughout cycles of cell division. Chloroplast division is achieved by a complex ring-shaped division machinery located on both the inner (stromal) and the outer (cytosolic) side of the chloroplast envelope. The inner division ring (termed the Z ring) is formed by the assembly of tubulin-like FtsZ1 and FtsZ2 proteins. ARC6 is a key chloroplast division protein that interacts with the Z ring. ARC6 spans the inner envelope membrane, is known to stabilize or maintain the Z ring, and anchors the Z ring to the inner membrane through interaction with FtsZ2. The underlying mechanism of Z-ring stabilization is not well understood. Here, biochemical and structural characterization of ARC6 was conducted using light scattering, sedimentation, and light and transmission electron microscopy. The recombinant protein was purified as a dimer. The results indicated that a truncated form of ARC6 (tARC6), representing the stromal portion of ARC6, affects FtsZ2 assembly without forming higher-order structures, and exerts its effect via FtsZ2 dynamics. tARC6 prevented GDP-induced FtsZ2 disassembly and caused a significant net increase in FtsZ2 assembly when GDP was present. Single particle analysis and 3D reconstruction were performed to elucidate the structural basis of ARC6 activity. Together, the data reveal that a dimeric form of tARC6 binds to FtsZ2 filaments and does not increase FtsZ polymerization rates but rather inhibits GDP-associated FtsZ2 disassembly. Published under license by The American Society for Biochemistry and Molecular Biology, Inc.
The bacterial tubulin FtsZ requires its intrinsically disordered linker to direct robust cell wall construction.

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Sundararajan, Kousik; Miguel, Amanda; Desmarais, Samantha M; Meier, Elizabeth L; Casey Huang, Kerwyn; Goley, Erin D

2015-06-23

The bacterial GTPase FtsZ forms a cytokinetic ring at midcell, recruits the division machinery and orchestrates membrane and peptidoglycan cell wall invagination. However, the mechanism for FtsZ regulation of peptidoglycan metabolism is unknown. The FtsZ GTPase domain is separated from its membrane-anchoring C-terminal conserved (CTC) peptide by a disordered C-terminal linker (CTL). Here we investigate CTL function in Caulobacter crescentus. Strikingly, production of FtsZ lacking the CTL (ΔCTL) is lethal: cells become filamentous, form envelope bulges and lyse, resembling treatment with β-lactam antibiotics. This phenotype is produced by FtsZ polymers bearing the CTC and a CTL shorter than 14 residues. Peptidoglycan synthesis still occurs downstream of ΔCTL; however, cells expressing ΔCTL exhibit reduced peptidoglycan crosslinking and longer glycan strands than wild type. Importantly, midcell proteins are still recruited to sites of ΔCTL assembly. We propose that FtsZ regulates peptidoglycan metabolism through a CTL-dependent mechanism that extends beyond simple protein recruitment.
An archaebacterial homologue of the essential eubacterial cell division protein FtsZ.

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Baumann, P; Jackson, S P

1996-06-25

Life falls into three fundamental domains--Archaea, Bacteria, and Eucarya (formerly archaebacteria, eubacteria, and eukaryotes,. respectively). Though Archaea lack nuclei and share many morphological features with Bacteria, molecular analyses, principally of the transcription and translation machineries, have suggested that Archaea are more related to Eucarya than to Bacteria. Currently, little is known about the archaeal cell division apparatus. In Bacteria, a crucial component of the cell division machinery is FtsZ, a GTPase that localizes to a ring at the site of septation. Interestingly, FtsZ is distantly related in sequence to eukaryotic tubulins, which also interact with GTP and are components of the eukaryotic cell cytoskeleton. By screening for the ability to bind radiolabeled nucleotides, we have identified a protein of the hyperthermophilic archaeon Pyrococcus woesei that interacts tightly and specifically with GTP. Furthermore, through screening an expression library of P. woesei genomic DNA, we have cloned the gene encoding this protein. Sequence comparisons reveal that the P. woesei GTP-binding protein is strikingly related in sequence to eubacterial FtsZ and is marginally more similar to eukaryotic tubulins than are bacterial FtsZ proteins. Phylogenetic analyses reinforce the notion that there is an evolutionary linkage between FtsZ and tubulins. These findings suggest that the archaeal cell division apparatus may be fundamentally similar to that of Bacteria and lead us to consider the evolutionary relationships between Archaea, Bacteria, and Eucarya.
Phenotypic indications of FtsZ inhibition in hok/sok-induced bacterial growth changes and stress response.

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Chukwudi, Chinwe Uzoma; Good, Liam

2018-01-01

The hok/sok locus has been shown to enhance the growth of bacteria in adverse growth conditions such as high temperature, low starting-culture densities and antibiotic treatment. This is in addition to their well-established plasmid-stabilization effect via post-segregational killing of plasmid-free daughter cells. It delays the onset of growth by prolonging the lag phase of bacterial culture, and increases the rate of exponential growth when growth eventually begins. This enables the cells adapt to the prevailing growth conditions and enhance their survival in stressful conditions. These effects functionally complement defective SOS response mechanism, and appear analogous to the growth effects of FtsZ in the SOS pathway. In this study, the role of FtsZ in the hok/sok-induced changes in bacterial growth and cell division was investigated. Morphologic studies of early growth-phase cultures and cells growing under temperature stress showed elongated cells typical of FtsZ inhibition/deficiency. Both ftsZ silencing and over-expression produced comparable growth effects in control cells, and altered the growth changes observed otherwise in the hok/sok + cells. These changes were diminished in SOS-deficient strain containing mutant FtsZ. The involvement of FtsZ in the hok/sok-induced growth changes may be exploited as drug target in host bacteria, which often propagate antibiotic resistance elements. Copyright © 2017 Elsevier Ltd. All rights reserved.
DamX Controls Reversible Cell Morphology Switching in Uropathogenic Escherichia coli

DEFF Research Database (Denmark)

Khandige, Surabhi; Antoinette Asferg, Cecilie; Rasmussen, Karina Juhl

2016-01-01

undertaking targeted investigations that are challenging to perform in animal infection models. IMPORTANCE: Urinary tract infections (UTIs) are most often caused by uropathogenic Escherichia coli (UPEC) and account for a considerable health care burden. UPEC exhibits a dynamic lifestyle in the course....... In aiming to uncover genes underlying the phenomenon of UPEC morphotype switching, this study identifies damX, a cell division gene, as a mediator of reversible filamentation during UTI. DamX-mediated filamentation represents an additional pathway for bacterial cell shape control, an alternative to Sul......A-mediated FtsZ sequestration during E. coli uropathogenesis, and hence represents a potential target for combating UTI....
A rhodanine derivative CCR-11 inhibits bacterial proliferation by inhibiting the assembly and GTPase activity of FtsZ.

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Singh, Parminder; Jindal, Bhavya; Surolia, Avadhesha; Panda, Dulal

2012-07-10

A perturbation of FtsZ assembly dynamics has been shown to inhibit bacterial cytokinesis. In this study, the antibacterial activity of 151 rhodanine compounds was assayed using Bacillus subtilis cells. Of 151 compounds, eight strongly inhibited bacterial proliferation at 2 μM. Subsequently, we used the elongation of B. subtilis cells as a secondary screen to identify potential FtsZ-targeted antibacterial agents. We found that three compounds significantly increased bacterial cell length. One of the three compounds, namely, CCR-11 [(E)-2-thioxo-5-({[3-(trifluoromethyl)phenyl]furan-2-yl}methylene)thiazolidin-4-one], inhibited the assembly and GTPase activity of FtsZ in vitro. CCR-11 bound to FtsZ with a dissociation constant of 1.5 ± 0.3 μM. A docking analysis indicated that CCR-11 may bind to FtsZ in a cavity adjacent to the T7 loop and that short halogen-oxygen, H-bonding, and hydrophobic interactions might be important for the binding of CCR-11 with FtsZ. CCR-11 inhibited the proliferation of B. subtilis cells with a half-maximal inhibitory concentration (IC(50)) of 1.2 ± 0.2 μM and a minimal inhibitory concentration of 3 μM. It also potently inhibited proliferation of Mycobacterium smegmatis cells. Further, CCR-11 perturbed Z-ring formation in B. subtilis cells; however, it neither visibly affected nucleoid segregation nor altered the membrane integrity of the cells. CCR-11 inhibited HeLa cell proliferation with an IC(50) value of 18.1 ± 0.2 μM (∼15 × IC(50) of B. subtilis cell proliferation). The results suggested that CCR-11 inhibits bacterial cytokinesis by inhibiting FtsZ assembly, and it can be used as a lead molecule to develop FtsZ-targeted antibacterial agents.
Toxicity of cadmium sulfide (CdS) nanoparticles against Escherichia coli and HeLa cells

International Nuclear Information System (INIS)

Hossain, Sk Tofajjen; Mukherjee, Samir Kumar

2013-01-01

Highlights: • Toxic effect of CdS NPs on the growth and cell division in E. coli was studied. • CdS NPs affected cell surface topology and cell division. • Downregulation of both FtsZ and FtsQ was observed due to NPs exposure. • CdS NPs affected HeLa cell morphology with fragmented nuclei. • All such effects might be due to elevated oxidative stress. -- Abstract: The present study endeavours to assess the toxic effect of synthesized CdS nanoparticles (NPs) on Escherichia coli and HeLa cells. The CdS NPs were characterized by DLS, XRD, TEM and AFM studies and the average size of NPs was revealed as ∼3 nm. On CdS NPs exposure bacterial cells changed morphological features to filamentous form and damage of the cell surface was found by AFM study. The expression of two conserved cell division components namely ftsZ and ftsQ in E. coli was decreased both at transcriptional and translational levels upon CdS NPs exposure. CdS NPs inhibited proper cell septum formation without affecting the nucleoid segregation. Viability of HeLa cells declined with increasing concentration of CdS NPs and the IC 50 value was found to be 4 μg/mL. NPs treated HeLa cells showed changed morphology with condensed and fragmented nuclei. Increased level of reactive oxygen species (ROS) was found both in E. coli and HeLa cells on CdS NPs exposure. The inverse correlation between declined cell viabilities and elevated ROS level suggested that oxidative stress seems to be the key event by which NPs induce toxicity both in E. coli and HeLa cells

LexA Binds to Transcription Regulatory Site of Cell Division Gene ftsZ in Toxic Cyanobacterium Microcystis aeruginosa.

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Honda, Takashi; Morimoto, Daichi; Sako, Yoshihiko; Yoshida, Takashi

2018-05-17

Previously, we showed that DNA replication and cell division in toxic cyanobacterium Microcystis aeruginosa are coordinated by transcriptional regulation of cell division gene ftsZ and that an unknown protein specifically bound upstream of ftsZ (BpFz; DNA-binding protein to an upstream site of ftsZ) during successful DNA replication and cell division. Here, we purified BpFz from M. aeruginosa strain NIES-298 using DNA-affinity chromatography and gel-slicing combined with gel electrophoresis mobility shift assay (EMSA). The N-terminal amino acid sequence of BpFz was identified as TNLESLTQ, which was identical to that of transcription repressor LexA from NIES-843. EMSA analysis using mutant probes showed that the sequence GTACTAN 3 GTGTTC was important in LexA binding. Comparison of the upstream regions of lexA in the genomes of closely related cyanobacteria suggested that the sequence TASTRNNNNTGTWC could be a putative LexA recognition sequence (LexA box). Searches for TASTRNNNNTGTWC as a transcriptional regulatory site (TRS) in the genome of M. aeruginosa NIES-843 showed that it was present in genes involved in cell division, photosynthesis, and extracellular polysaccharide biosynthesis. Considering that BpFz binds to the TRS of ftsZ during normal cell division, LexA may function as a transcriptional activator of genes related to cell reproduction in M. aeruginosa, including ftsZ. This may be an example of informality in the control of bacterial cell division.
FtsZ-less prokaryotic cell division as well as FtsZ- and dynamin-less chloroplast and non-photosynthetic plastid division

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Shin-Ya eMiyagishima

2014-09-01

Full Text Available The chloroplast division machinery is a mixture of a stromal FtsZ-based complex descended from a cyanobacterial ancestor of chloroplasts and a cytosolic dynamin-related protein (DRP 5B-based complex derived from the eukaryotic host. Molecular genetic studies have shown that each component of the division machinery is normally essential for normal chloroplast division. However, several exceptions have been found. In the absence of the FtsZ ring, nonphotosynthetic plastids are able to proliferate, likely by elongation and budding. Depletion of DRP5B impairs, but does not stop chloroplast division. Chloroplasts in glaucophytes, which possesses a peptidoglycan (PG layer, divide without DRP5B. Certain parasitic eukaryotes possess nonphotosynthetic plastids of secondary endosymbiotic origin, but neither FtsZ nor DRP5B is encoded in their genomes. Elucidation of the FtsZ- and/or DRP5B-less chloroplast division mechanism will lead to a better understanding of the function and evolution of the chloroplast division machinery and the finding of the as-yet-unknown mechanism that is likely involved in chloroplast division. Recent studies have shown that FtsZ was lost from a variety of prokaryotes, many of which lost PG by regressive evolution. In addition, even some of the FtsZ-bearing bacteria are able to divide when FtsZ and PG are depleted experimentally. In some cases, alternative mechanisms for cell division, such as budding by an increase of the cell surface-to-volume ratio, are proposed. Although PG is believed to have been lost from chloroplasts other than in glaucophytes, there is some indirect evidence for the existence of PG in chloroplasts. Such information is also useful for understanding how nonphotosynthetic plastids are able to divide in FtsZ-depleted cells and the reason for the retention of FtsZ in chloroplast division. Here we summarize information to facilitate analyses of FtsZ- and/or DRP5B-less chloroplast and nonphotosynthetic plastid
Two dynamin-like proteins stabilize FtsZ rings during Streptomyces sporulation.

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Schlimpert, Susan; Wasserstrom, Sebastian; Chandra, Govind; Bibb, Maureen J; Findlay, Kim C; Flärdh, Klas; Buttner, Mark J

2017-07-25

During sporulation, the filamentous bacteria Streptomyces undergo a massive cell division event in which the synthesis of ladders of sporulation septa convert multigenomic hyphae into chains of unigenomic spores. This process requires cytokinetic Z-rings formed by the bacterial tubulin homolog FtsZ, and the stabilization of the newly formed Z-rings is crucial for completion of septum synthesis. Here we show that two dynamin-like proteins, DynA and DynB, play critical roles in this process. Dynamins are a family of large, multidomain GTPases involved in key cellular processes in eukaryotes, including vesicle trafficking and organelle division. Many bacterial genomes encode dynamin-like proteins, but the biological function of these proteins has remained largely enigmatic. Using a cell biological approach, we show that the two Streptomyces dynamins specifically localize to sporulation septa in an FtsZ-dependent manner. Moreover, dynamin mutants have a cell division defect due to the decreased stability of sporulation-specific Z-rings, as demonstrated by kymographs derived from time-lapse images of FtsZ ladder formation. This defect causes the premature disassembly of individual Z-rings, leading to the frequent abortion of septum synthesis, which in turn results in the production of long spore-like compartments with multiple chromosomes. Two-hybrid analysis revealed that the dynamins are part of the cell division machinery and that they mediate their effects on Z-ring stability during developmentally controlled cell division via a network of protein-protein interactions involving DynA, DynB, FtsZ, SepF, SepF2, and the FtsZ-positioning protein SsgB.
Large ring polymers align FtsZ polymers for normal septum formation

NARCIS (Netherlands)

Guendogdu, Muhammet E.; Kawai, Yoshikazu; Pavlendova, Nada; Ogasawara, Naotake; Errington, Jeff; Scheffers, Dirk-Jan; Hamoen, Leendert W.; Gündoğdu, Muhammet E.

2011-01-01

Cytokinesis in bacteria is initiated by polymerization of the tubulin homologue FtsZ into a circular structure at midcell, the Z-ring. This structure functions as a scaffold for all other cell division proteins. Several proteins support assembly of the Z-ring, and one such protein, SepF, is required
Role of SbmA in the Uptake of Peptide Nucleic Acid (PNA)-Peptide Conjugates in E. coli

DEFF Research Database (Denmark)

Ghosal, Anubrata; Vitali, Ally; Stach, James E M

2013-01-01

Antisense PNA oligomers targeting essential genes (acpP or ftsZ) and conjugated to the delivery peptide L((KFF)(3)K) show complete growth inhibition of wild type E. coli strain (MG1655) with submicromolar MIC. In this study we show that resistant mutants generated against such PNA......-peptide conjugates had disruptions in the region of sbmA, a gene encoding an inner membrane peptide transporter. The wild type sensitivity to the PNA conjugates was re-established in the resistance mutants by complementation with sbmA. Furthermore, deletion of sbmA in E. coli AS19, a strain that is sensitive...
Inhibiting the growth of methicillin-resistant Staphylococcus aureus in vitro with antisense peptide nucleic acid conjugates targeting the ftsZ gene

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Shumei Liang

2015-01-01

Conclusion: Our results demonstrate that the potent effects of PNAs on bacterial growth and cell viability were mediated by the down-regulation or even knock-out of ftsZ gene expression. This highlights the utility of ftsZ as a promising target for the development of new antisense antibacterial agents to treat MRSA infections.
Genetic and Biochemical Characterization of the MinC-FtsZ Interaction in Bacillus subtilis

Science.gov (United States)

Castellen, Patricia; Nogueira, Maria Luiza C.; Bettini, Jefferson; Portugal, Rodrigo V.; Zeri, Ana Carolina M.; Gueiros-Filho, Frederico J.

2013-01-01

Cell division in bacteria is regulated by proteins that interact with FtsZ and modulate its ability to polymerize into the Z ring structure. The best studied of these regulators is MinC, an inhibitor of FtsZ polymerization that plays a crucial role in the spatial control of Z ring formation. Recent work established that E. coli MinC interacts with two regions of FtsZ, the bottom face of the H10 helix and the extreme C-terminal peptide (CTP). Here we determined the binding site for MinC on Bacillus subtilis FtsZ. Selection of a library of FtsZ mutants for survival in the presence of Min overexpression resulted in the isolation of 13 Min-resistant mutants. Most of the substitutions that gave rise to Min resistance clustered around the H9 and H10 helices in the C-terminal domain of FtsZ. In addition, a mutation in the CTP of B. subtilis FtsZ also produced MinC resistance. Biochemical characterization of some of the mutant proteins showed that they exhibited normal polymerization properties but reduced interaction with MinC, as expected for binding site mutations. Thus, our study shows that the overall architecture of the MinC-FtsZ interaction is conserved in E. coli and B. subtilis. Nevertheless, there was a clear difference in the mutations that conferred Min resistance, with those in B. subtilis FtsZ pointing to the side of the molecule rather than to its polymerization interface. This observation suggests that the mechanism of Z ring inhibition by MinC differs in both species. PMID:23577149
In vivo structure of the E. coli FtsZ-ring revealed by photoactivated localization microscopy (PALM).

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Fu, Guo; Huang, Tao; Buss, Jackson; Coltharp, Carla; Hensel, Zach; Xiao, Jie

2010-09-13

The FtsZ protein, a tubulin-like GTPase, plays a pivotal role in prokaryotic cell division. In vivo it localizes to the midcell and assembles into a ring-like structure-the Z-ring. The Z-ring serves as an essential scaffold to recruit all other division proteins and generates contractile force for cytokinesis, but its supramolecular structure remains unknown. Electron microscopy (EM) has been unsuccessful in detecting the Z-ring due to the dense cytoplasm of bacterial cells, and conventional fluorescence light microscopy (FLM) has only provided images with limited spatial resolution (200-300 nm) due to the diffraction of light. Hence, given the small sizes of bacteria cells, identifying the in vivo structure of the Z-ring presents a substantial challenge. Here, we used photoactivated localization microscopy (PALM), a single molecule-based super-resolution imaging technique, to characterize the in vivo structure of the Z-ring in E. coli. We achieved a spatial resolution of ∼35 nm and discovered that in addition to the expected ring-like conformation, the Z-ring of E. coli adopts a novel compressed helical conformation with variable helical length and pitch. We measured the thickness of the Z-ring to be ∼110 nm and the packing density of FtsZ molecules inside the Z-ring to be greater than what is expected for a single-layered flat ribbon configuration. Our results strongly suggest that the Z-ring is composed of a loose bundle of FtsZ protofilaments that randomly overlap with each other in both longitudinal and radial directions of the cell. Our results provide significant insight into the spatial organization of the Z-ring and open the door for further investigations of structure-function relationships and cell cycle-dependent regulation of the Z-ring.
In vivo structure of the E. coli FtsZ-ring revealed by photoactivated localization microscopy (PALM.

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Guo Fu

2010-09-01

Full Text Available The FtsZ protein, a tubulin-like GTPase, plays a pivotal role in prokaryotic cell division. In vivo it localizes to the midcell and assembles into a ring-like structure-the Z-ring. The Z-ring serves as an essential scaffold to recruit all other division proteins and generates contractile force for cytokinesis, but its supramolecular structure remains unknown. Electron microscopy (EM has been unsuccessful in detecting the Z-ring due to the dense cytoplasm of bacterial cells, and conventional fluorescence light microscopy (FLM has only provided images with limited spatial resolution (200-300 nm due to the diffraction of light. Hence, given the small sizes of bacteria cells, identifying the in vivo structure of the Z-ring presents a substantial challenge. Here, we used photoactivated localization microscopy (PALM, a single molecule-based super-resolution imaging technique, to characterize the in vivo structure of the Z-ring in E. coli. We achieved a spatial resolution of ∼35 nm and discovered that in addition to the expected ring-like conformation, the Z-ring of E. coli adopts a novel compressed helical conformation with variable helical length and pitch. We measured the thickness of the Z-ring to be ∼110 nm and the packing density of FtsZ molecules inside the Z-ring to be greater than what is expected for a single-layered flat ribbon configuration. Our results strongly suggest that the Z-ring is composed of a loose bundle of FtsZ protofilaments that randomly overlap with each other in both longitudinal and radial directions of the cell. Our results provide significant insight into the spatial organization of the Z-ring and open the door for further investigations of structure-function relationships and cell cycle-dependent regulation of the Z-ring.
Influence of GTP/GDP and magnesium ion on the solvated structure of the protein FtsZ: a molecular dynamics study.

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Jamous, Carla; Basdevant, Nathalie; Ha-Duong, Tap

2014-01-01

We present here a structural analysis of ten extensive all-atom molecular dynamics simulations of the monomeric protein FtsZ in various binding states. Since the polymerization and GTPase activities of FtsZ depend on the nature of a bound nucleotide as well as on the presence of a magnesium ion, we studied the structural differences between the average conformations of the following five systems: FtsZ-Apo, FtsZ-GTP, FtsZ-GDP, FtsZ-GTP-Mg, and FtsZ-GDP-Mg. The in silico solvated average structure of FtsZ-Apo significantly differs from the crystallographic structure 1W59 of FtsZ which was crystallized in a dimeric form without nucleotide and magnesium. The simulated Apo form of the protein also clearly differs from the FtsZ structures when it is bound to its ligand, the most important discrepancies being located in the loops surrounding the nucleotide binding pocket. The three average structures of FtsZ-GTP, FtsZ-GDP, and FtsZ-GTP-Mg are overall similar, except for the loop T7 located at the opposite side of the binding pocket and whose conformation in FtsZ-GDP notably differs from the one in FtsZ-GTP and FtsZ-GTP-Mg. The presence of a magnesium ion in the binding pocket has no impact on the FtsZ conformation when it is bound to GTP. In contrast, when the protein is bound to GDP, the divalent cation causes a translation of the nucleotide outwards the pocket, inducing a significant conformational change of the loop H6-H7 and the top of helix H7.
Bacillus subtilis SepF Binds to the C-Terminus of FtsZ

NARCIS (Netherlands)

Krol, Ewa; van Kessel, Sebastiaan P.; van Bezouwen, Laura S.; Kumar, Neeraj; Boekema, Egbert J.; Scheffers, Dirk-Jan

2012-01-01

Bacterial cell division is mediated by a multi-protein machine known as the "divisome", which assembles at the site of cell division. Formation of the divisome starts with the polymerization of the tubulin-like protein FtsZ into a ring, the Z-ring. Z-ring formation is under tight control to ensure
Intracellular crowding effects on the self-association of the bacterial cell division protein FtsZ.

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Naddaf, Lamis; Sayyed-Ahmad, Abdallah

2014-12-15

The dimerization rate of the bacterial cell division protein FtsZ is strongly affected by the intracellular crowding. Yet the complexity of the intracellular environment makes it difficult to investigate via all-atom molecular dynamics or other detailed theoretical methods. We study the crowding effect on FtsZ dimerization which is the first step of an oligomerization process that results in more elaborate supramolecular structures. In particular, we consider the effect of intracellular crowding on the reaction rates, and their dependence on the different concentrations of crowding agents. We achieved this goal by using Brownian dynamics (BD) simulation techniques and a modified post-processing approach in which we decompose the rate constant in crowded media as a product of the rate constant in the dilute solution times a factor that incorporates the crowding effect. The latter factor accounts for the diffusion reduction and crowder induced energy. In addition we include the crowding effects on water viscosity in the BD simulations of crowded media. We finally show that biomolecular crowding has a considerable effect on the FtsZ dimerization by increasing the dimerization rate constant from 2.6×10(7)M(-1)s(-1) in the absence of crowders to 1.0×10(8)M(-1)s(-1) at crowding level of 0.30. Copyright © 2014 Elsevier Inc. All rights reserved.
Constitutive expression of ftsZ overrides the whi developmental genes to initiate sporulation of Streptomyces coelicolor.

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Willemse, Joost; Mommaas, A Mieke; van Wezel, Gilles P

2012-03-01

The filamentous soil bacteria Streptomyces undergo a highly complex developmental programme. Before streptomycetes commit themselves to sporulation, distinct morphological checkpoints are passed in the aerial hyphae that are subject to multi-level control by the whi sporulation genes. Here we show that whi-independent expression of FtsZ restores sporulation to the early sporulation mutants whiA, whiB, whiG, whiH, whiI and whiJ. Viability, stress resistance and high-resolution electron microscopy underlined that viable spores were formed. However, spores from sporulation-restored whiA and whiG mutants showed defects in DNA segregation/condensation, while spores from the complemented whiB mutant had increased stress sensitivity, perhaps as a result of changes in the spore sheath. In contrast to the whi mutants, normal sporulation of ssgB null mutants-which fail to properly localise FtsZ-could not be restored by enhancing FtsZ protein levels, forming spore-like bodies that lack spore walls. Our data strongly suggest that the whi genes control a decisive event towards sporulation of streptomycetes, namely the correct timing of developmental ftsZ transcription. The biological significance may be to ensure that sporulation-specific cell division will only start once sufficient aerial mycelium biomass has been generated. Our data shed new light on the longstanding question as to how whi genes control sporulation, which has intrigued scientists for four decades.
Engineering cell wall synthesis mechanism for enhanced PHB accumulation in E. coli.

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Zhang, Xing-Chen; Guo, Yingying; Liu, Xu; Chen, Xin-Guang; Wu, Qiong; Chen, Guo-Qiang

2018-01-01

The rigidity of bacterial cell walls synthesized by a complicated pathway limit the cell shapes as coccus, bar or ellipse or even fibers. A less rigid bacterium could be beneficial for intracellular accumulation of poly-3-hydroxybutyrate (PHB) as granular inclusion bodies. To understand how cell rigidity affects PHB accumulation, E. coli cell wall synthesis pathway was reinforced and weakened, respectively. Cell rigidity was achieved by thickening the cell walls via insertion of a constitutive gltA (encoding citrate synthase) promoter in front of a series of cell wall synthesis genes on the chromosome of several E. coli derivatives, resulting in 1.32-1.60 folds increase of Young's modulus in mechanical strength for longer E. coli cells over-expressing fission ring FtsZ protein inhibiting gene sulA. Cell rigidity was weakened by down regulating expressions of ten genes in the cell wall synthesis pathway using CRISPRi, leading to elastic cells with more spaces for PHB accumulation. The regulation on cell wall synthesis changes the cell rigidity: E. coli with thickened cell walls accumulated only 25% PHB while cell wall weakened E. coli produced 93% PHB. Manipulation on cell wall synthesis mechanism adds another possibility to morphology engineering of microorganisms. Copyright © 2017 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.
Assembly of the MreB-associated cytoskeletal ring of Escherichia coli.

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Vats, Purva; Shih, Yu-Ling; Rothfield, Lawrence

2009-04-01

The Escherichia coli actin homologue MreB is part of a helical cytoskeletal structure that winds around the cell between the two poles. It has been shown that MreB redistributes during the cell cycle to form circumferential ring structures that flank the cytokinetic FtsZ ring and appear to be associated with division and segregation of the helical cytoskeleton. We show here that the MreB cytoskeletal ring also contains the MreC, MreD, Pbp2 and RodA proteins. Assembly of MreB, MreC, MreD and Pbp2 into the ring structure required the FtsZ ring but no other known components of the cell division machinery, whereas assembly of RodA into the cytoskeletal ring required one or more additional septasomal components. Strikingly, MreB, MreC, MreD and RodA were each able to independently assemble into the cytoskeletal ring and coiled cytoskeletal structures in the absence of any of the other ring components. This excludes the possibility that one or more of these proteins acts as a scaffold for incorporation of the other proteins into these structures. In contrast, incorporation of Pbp2 required the presence of MreC, which may provide a docking site for Pbp2 entry.
Engineering the growth pattern and cell morphology for enhanced PHB production by Escherichia coli.

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Wu, Hong; Chen, Jinchun; Chen, Guo-Qiang

2016-12-01

E. coli JM109∆envC∆nlpD deleted with genes envC and nlpD responsible for degrading peptidoglycan (PG) led to long filamentous cell shapes. When cell fission ring location genes minC and minD of Escherichia coli were deleted, E. coli JM109∆minCD changed the cell growth pattern from binary division to multiple fissions. Bacterial morphology can be further engineered by overexpressing sulA gene resulting in inhibition on FtsZ, thus generating very long cellular filaments. By overexpressing sulA in E. coli JM109∆envC∆nlpD and E. coli JM109∆minCD harboring poly(3-hydroxybutyrate) (PHB) synthesis operon phbCAB encoded in plasmid pBHR68, respectively, both engineered cells became long filaments and accumulated more PHB compared with the wild-type. Under same shake flask growth conditions, E. coli JM109∆minCD (pBHR68) overexpressing sulA grown in multiple fission pattern accumulated approximately 70 % PHB in 9 g/L cell dry mass (CDM), which was significantly higher than E. coli JM109∆envC∆nlpD and the wild type, that produced 7.6 g/L and 8 g/L CDM containing 64 % and 51 % PHB, respectively. Results demonstrated that a combination of the new division pattern with elongated shape of E. coli improved PHB production. This provided a new vision on the enhanced production of inclusion bodies.
The N-succinyl-l,l-diaminopimelic acid desuccinylase DapE acts through ZapB to promote septum formation in Escherichia coli.

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Du, Shishen; Lutkenhaus, Joe

2017-07-01

Spatial regulation of cell division in Escherichia coli occurs at the stage of Z ring formation. It consists of negative (the Min and NO systems) and positive (Ter signal mediated by MatP/ZapA/ZapB) regulators. Here, we find that N-succinyl-L,L-diaminopimelic acid desuccinylase (DapE) facilitates functional Z ring formation by strengthening the Ter signal via ZapB. DapE depends on ZapB to localize to the Z ring and its overproduction suppresses the division defect caused by loss of both the Min and NO systems. DapE shows a strong interaction with ZapB and requires the presence of ZapB to exert its function in division. Consistent with the idea that DapE strengthens the Ter signal, overproduction of DapE supports cell division with reduced FtsZ levels and provides some resistance to the FtsZ inhibitors MinCD and SulA, while deletion of dapE, like deletion of zapB, exacerbates the phenotypes of cells impaired in Z ring formation such as ftsZ84 or a min mutant. Taken together, our results report DapE as a new component of the divisome that promotes the integrity of the Z ring by acting through ZapB and raises the possibility of the existence of additional divisome proteins that also function in other cellular processes. © 2017 John Wiley & Sons Ltd.
SAR studies on trisubstituted benzimidazoles as inhibitors of Mtb FtsZ for the development of novel antitubercular agents.

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Awasthi, Divya; Kumar, Kunal; Knudson, Susan E; Slayden, Richard A; Ojima, Iwao

2013-12-12

FtsZ, an essential protein for bacterial cell division, is a highly promising therapeutic target, especially for the discovery and development of new-generation anti-TB agents. Following up the identification of two lead 2,5,6-trisubstituted benzimidazoles, 1 and 2, targeting Mtb-FtsZ in our previous study, an extensive SAR study for optimization of these lead compounds was performed through systematic modification of the 5 and 6 positions. This study has successfully led to the discovery of a highly potent advanced lead 5f (MIC = 0.06 μg/mL) and several other compounds with comparable potencies. These advanced lead compounds possess a dimethylamino group at the 6 position. The functional groups at the 5 position exhibit substantial effects on the antibacterial activity as well. In vitro experiments such as the FtsZ polymerization inhibitory assay and TEM analysis of Mtb-FtsZ treated with 5f and others indicate that Mtb-FtsZ is the molecular target for their antibacterial activity.
Ecological and genetic determinants of plasmid distribution in Escherichia coli.

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Medaney, Frances; Ellis, Richard J; Raymond, Ben

2016-11-01

Bacterial plasmids are important carriers of virulence and antibiotic resistance genes. Nevertheless, little is known of the determinants of plasmid distribution in bacterial populations. Here the factors affecting the diversity and distribution of the large plasmids of Escherichia coli were explored in cattle grazing on semi-natural grassland, a set of populations with low frequencies of antibiotic resistance genes. Critically, the population genetic structure of bacterial hosts was chararacterized. This revealed structured E. coli populations with high diversity between sites and individuals but low diversity within cattle hosts. Plasmid profiles, however, varied considerably within the same E. coli genotype. Both ecological and genetic factors affected plasmid distribution: plasmid profiles were affected by site, E. coli diversity, E. coli genotype and the presence of other large plasmids. Notably 3/26 E. coli serotypes accounted for half the observed plasmid-free isolates indicating that within species variation can substantially affect carriage of the major conjugative plasmids. The observed population structure suggest that most of the opportunities for within species plasmid transfer occur between different individuals of the same genotype and support recent experimental work indicating that plasmid-host coevolution, and epistatic interactions on fitness costs are likely to be important in determining occupancy. © 2016 The Authors. Environmental Microbiology published by Society for Applied Microbiology and John Wiley & Sons Ltd.
How much territory can a single E. coli cell control?

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Ziad W. El-Hajj

2015-04-01

Full Text Available Bacteria have been traditionally classified in terms of size and shape and are best known for their very small size. E. coli cells in particular are small rods, each 1-2 microns. However the size varies with the medium, and faster growing cells are larger because they must have more ribosomes to make more protoplasm per unit time, and ribosomes take up space. Indeed, Maaloe's experiments on how E. coli establishes its size began with shifts between rich and poor media.Recently much larger bacteria have been described, including Epulopiscium fishelsoni at 700 μm and Thiomargarita namibiensisis at 750 μm. These are not only much longer than E. coli cells but also much wider, necessitating considerable intracellular organization. Epulopiscium cells for instance, at 80 μm wide, enclose a large enough volume of cytoplasm to present it with major transport problems.This review surveys E. coli cells much longer than those which grow in nature and in usual lab cultures. These include cells mutated in a single gene (metK which are 2-4x longer than their nonmutated parent. This metK mutant stops dividing when slowly starved of S-adenosylmethionine but continues to elongate to 50 μm and more. FtsZ mutants have been routinely isolated as long cells which form during growth at 42°C. The SOS response is a well-characterized regulatory network that is activated in response to DNA damage and also results in cell elongation. Our champion elongated E. coli is a metK strain with a further, as yet unidentified mutation, which reaches 750 μm with no internal divisions and no increase in width.

Genetic determinants of heat resistance in Escherichia coli

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Ryan eMercer

2015-09-01

Full Text Available Escherichia coli AW1.7 is a heat resistant food isolate and the occurrence of pathogenic strains with comparable heat resistance may pose a risk to food safety. To identify the genetic determinants of heat resistance, 29 strains of E. coli that differed in their of heat resistance were analyzed by comparative genomics. Strains were classified as highly heat resistant strains, exhibiting a D60-value of more than 6 min; moderately heat resistant strains, exhibiting a D60-value of more than 1 min; or as heat sensitive. A ~14 kb genomic island containing 16 predicted open reading frames encoding putative heat shock proteins and proteases was identified only in highly heat resistant strains. The genomic island was termed the locus of heat resistance (LHR. This putative operon is flanked by mobile elements and possesses >99% sequence identity to genomic islands contributing to heat resistance in Cronobacter sakazakii and Klebsiella pneumoniae. An additional 41 LHR sequences with >87% sequence identity were identified in 11 different species of β- and γ-proteobacteria. Cloning of the full length LHR conferred high heat resistance to the heat sensitive E. coli AW1.7ΔpHR1 and DH5α. The presence of the LHR correlates perfectly to heat resistance in several species of Enterobacteriaceae and occurs at a frequency of 2% of all E. coli genomes, including pathogenic strains. This study suggests the LHR has been laterally exchanged among the β- and γ-proteobacteria and is a reliable indicator of high heat resistance in E. coli.
Pharmacophore generation, atom-based 3D-QSAR, molecular docking and molecular dynamics simulation studies on benzamide analogues as FtsZ inhibitors.

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Tripathy, Swayansiddha; Azam, Mohammed Afzal; Jupudi, Srikanth; Sahu, Susanta Kumar

2017-10-11

FtsZ is an appealing target for the design of antimicrobial agent that can be used to defeat the multidrug-resistant bacterial pathogens. Pharmacophore modelling, molecular docking and molecular dynamics (MD) simulation studies were performed on a series of three-substituted benzamide derivatives. In the present study a five-featured pharmacophore model with one hydrogen bond acceptors, one hydrogen bond donors, one hydrophobic and two aromatic rings was developed using 97 molecules having MIC values ranging from .07 to 957 μM. A statistically significant 3D-QSAR model was obtained using this pharmacophore hypothesis with a good correlation coefficient (R 2 = .8319), cross validated coefficient (Q 2 = .6213) and a high Fisher ratio (F = 103.9) with three component PLS factor. A good correlation between experimental and predicted activity of the training (R 2 = .83) and test set (R 2 = .67) molecules were displayed by ADHRR.1682 model. The generated model was further validated by enrichment studies using the decoy test and MAE-based criteria to measure the efficiency of the model. The docking studies of all selected inhibitors in the active site of FtsZ protein showed crucial hydrogen bond interactions with Val 207, Asn 263, Leu 209, Gly 205 and Asn-299 residues. The binding free energies of these inhibitors were calculated by the molecular mechanics/generalized born surface area VSGB 2.0 method. Finally, a 15 ns MD simulation was done to confirm the stability of the 4DXD-ligand complex. On a wider scope, the prospect of present work provides insight in designing molecules with better selective FtsZ inhibitory potential.
Genes involved in cell division in mycoplasmas

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Frank Alarcón

2007-01-01

Full Text Available Bacterial cell division has been studied mainly in model systems such as Escherichia coli and Bacillus subtilis, where it is described as a complex process with the participation of a group of proteins which assemble into a multiprotein complex called the septal ring. Mycoplasmas are cell wall-less bacteria presenting a reduced genome. Thus, it was important to compare their genomes to analyze putative genes involved in cell division processes. The division and cell wall (dcw cluster, which in E. coli and B. subtilis is composed of 16 and 17 genes, respectively, is represented by only three to four genes in mycoplasmas. Even the most conserved protein, FtsZ, is not present in all mycoplasma genomes analyzed so far. A model for the FtsZ protein from Mycoplasma hyopneumoniae and Mycoplasma synoviae has been constructed. The conserved residues, essential for GTP/GDP binding, are present in FtsZ from both species. A strong conservation of hydrophobic amino acid patterns is observed, and is probably necessary for the structural stability of the protein when active. M. synoviae FtsZ presents an extended amino acid sequence at the C-terminal portion of the protein, which may participate in interactions with other still unknown proteins crucial for the cell division process.
Design, synthesis and evaluation of novel 2,5,6-trisubstituted benzimidazoles targeting FtsZ as antitubercular agents.

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Park, Bora; Awasthi, Divya; Chowdhury, Soumya R; Melief, Eduard H; Kumar, Kunal; Knudson, Susan E; Slayden, Richard A; Ojima, Iwao

2014-05-01

Filamenting temperature-sensitive protein Z (FtsZ), an essential cell division protein, is a promising target for the drug discovery of new-generation antibacterial agents against various bacterial pathogens. As a part of SAR studies on benzimidazoles, we have synthesized a library of 376 novel 2,5,6-trisubstituted benzimidazoles, bearing ether or thioether linkage at the 6-position. In a preliminary HTP screening against Mtb H37Rv, 108 compounds were identified as hits at a cut off concentration of 5 μg/mL. Among those hits, 10 compounds exhibited MIC values in the range of 0.63-12.5 μg/mL. Light scattering assay and TEM analysis with the most potent compound 5a clearly indicate that its molecular target is Mtb-FtsZ. Also, the Kd of 5a with Mtb-FtsZ was determined to be 1.32 μM. Copyright © 2014 Elsevier Ltd. All rights reserved.
Antimicrobial activity of apple cider vinegar against Escherichia coli, Staphylococcus aureus and Candida albicans; downregulating cytokine and microbial protein expression.

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Yagnik, Darshna; Serafin, Vlad; J Shah, Ajit

2018-01-29

The global escalation in antibiotic resistance cases means alternative antimicrobials are essential. The aim of this study was to investigate the antimicrobial capacity of apple cider vinegar (ACV) against E. coli, S. aureus and C. albicans. The minimum dilution of ACV required for growth inhibition varied for each microbial species. For C. albicans, a 1/2 ACV had the strongest effect, S. aureus, a 1/25 dilution ACV was required, whereas for E-coli cultures, a 1/50 ACV dilution was required (p < 0.05). Monocyte co-culture with microbes alongside ACV resulted in dose dependent downregulation of inflammatory cytokines (TNFα, IL-6). Results are expressed as percentage decreases in cytokine secretion comparing ACV treated with non-ACV treated monocytes cultured with E-coli (TNFα, 99.2%; IL-6, 98%), S. aureus (TNFα, 90%; IL-6, 83%) and C. albicans (TNFα, 83.3%; IL-6, 90.1%) respectively. Proteomic analyses of microbes demonstrated that ACV impaired cell integrity, organelles and protein expression. ACV treatment resulted in an absence in expression of DNA starvation protein, citrate synthase, isocitrate and malate dehydrogenases in E-coli; chaperone protein DNak and ftsz in S. aureus and pyruvate kinase, 6-phosphogluconate dehydrogenase, fructose bisphosphate were among the enzymes absent in C.albican cultures. The results demonstrate ACV has multiple antimicrobial potential with clinical therapeutic implications.
Postgenomics Characterization of an Essential Genetic Determinant of Mammary Pathogenic Escherichia coli

Science.gov (United States)

2018-01-01

ABSTRACT Escherichia coli are major bacterial pathogens causing bovine mastitis, a disease of great economic impact on dairy production worldwide. This work aimed to study the virulence determinants of mammary pathogenic E. coli (MPEC). By whole-genome sequencing analysis of 40 MPEC and 22 environmental (“dairy-farm” E. coli [DFEC]) strains, we found that only the fec locus (fecIRABCDE) for ferric dicitrate uptake was present in the core genome of MPEC and that it was absent in DFEC genomes (P mastitis, whereas the fec+ DFEC K71 mutant was able to trigger intramammary inflammation. For the first time, a single molecular locus was shown to be crucial in MPEC pathogenicity. PMID:29615502
Postgenomics Characterization of an Essential Genetic Determinant of Mammary Pathogenic Escherichia coli.

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Blum, Shlomo E; Goldstone, Robert J; Connolly, James P R; Répérant-Ferter, Maryline; Germon, Pierre; Inglis, Neil F; Krifucks, Oleg; Mathur, Shubham; Manson, Erin; Mclean, Kevin; Rainard, Pascal; Roe, Andrew J; Leitner, Gabriel; Smith, David G E

2018-04-03

Escherichia coli are major bacterial pathogens causing bovine mastitis, a disease of great economic impact on dairy production worldwide. This work aimed to study the virulence determinants of mammary pathogenic E. coli (MPEC). By whole-genome sequencing analysis of 40 MPEC and 22 environmental ("dairy-farm" E. coli [DFEC]) strains, we found that only the fec locus ( fecIRABCDE ) for ferric dicitrate uptake was present in the core genome of MPEC and that it was absent in DFEC genomes ( P price of dairy products on supermarket shelves and the financial hardships suffered by dairy farmers. Mastitis is also the leading reason for the use of antibiotics in dairy farms. Good farm management practices in many countries have dramatically reduced the incidence of contagious mastitis; however, the problems associated with the incidence of environmental mastitis caused by bacteria such as Escherichia coli have proven intractable. E. coli bacteria cause acute mastitis, which affects the health and welfare of cows and in extreme cases may be fatal. Here we show for the first time that the pathogenicity of E. coli causing mastitis in cows is highly dependent on the fecIRABCDE ferric citrate uptake system that allows the bacterium to capture iron from citrate. The Fec system is highly expressed during infection in the bovine udder and is ubiquitous in and necessary for the E. coli bacteria that cause mammary infections in cattle. These results have far-reaching implications, raising the possibility that mastitis may be controllable by targeting this system. Copyright © 2018 Blum et al.
Exposure to Sub-lethal 2,4-Dichlorophenoxyacetic Acid Arrests Cell Division and Alters Cell Surface Properties in Escherichia coli

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Bhat, Supriya V.; Kamencic, Belma; Körnig, André; Shahina, Zinnat; Dahms, Tanya E. S.

2018-01-01

Escherichia coli is a robust, easily adaptable and culturable bacterium in vitro, and a model bacterium for studying the impact of xenobiotics in the environment. We have used correlative atomic force – laser scanning confocal microscopy (AFM-LSCM) to characterize the mechanisms of cellular response to the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D). One of the most extensively used herbicides world-wide, 2,4-D is known to cause hazardous effects in diverse non-target organisms. Sub-lethal concentrations of 2,4-D caused DNA damage in E. coli WM1074 during short exposure periods which increased significantly over time. In response to 2,4-D, FtsZ and FtsA relocalized within seconds, coinciding with the complete inhibition of cell septation and cell elongation. Exposure to 2,4-D also resulted in increased activation of the SOS response. Changes to cell division were accompanied by concomitant changes to surface roughness, elasticity and adhesion in a time-dependent manner. This is the first study describing the mechanistic details of 2,4-D at sub-lethal levels in bacteria. Our study suggests that 2,4-D arrests E. coli cell division within seconds after exposure by disrupting the divisome complex, facilitated by dissipation of membrane potential. Over longer exposures, 2,4-D causes filamentation as a result of an SOS response to oxidative stress induced DNA damage. PMID:29472899
Concurrent growth rate and transcript analyses reveal essential gene stringency in Escherichia coli.

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Shan Goh

Full Text Available BACKGROUND: Genes essential for bacterial growth are of particular scientific interest. Many putative essential genes have been identified or predicted in several species, however, little is known about gene expression requirement stringency, which may be an important aspect of bacterial physiology and likely a determining factor in drug target development. METHODOLOGY/PRINCIPAL FINDINGS: Working from the premise that essential genes differ in absolute requirement for growth, we describe silencing of putative essential genes in E. coli to obtain a titration of declining growth rates and transcript levels by using antisense peptide nucleic acids (PNA and expressed antisense RNA. The relationship between mRNA decline and growth rate decline reflects the degree of essentiality, or stringency, of an essential gene, which is here defined by the minimum transcript level for a 50% reduction in growth rate (MTL(50. When applied to four growth essential genes, both RNA silencing methods resulted in MTL(50 values that reveal acpP as the most stringently required of the four genes examined, with ftsZ the next most stringently required. The established antibacterial targets murA and fabI were less stringently required. CONCLUSIONS: RNA silencing can reveal stringent requirements for gene expression with respect to growth. This method may be used to validate existing essential genes and to quantify drug target requirement.
Novel Coiled-Coil Cell Division Factor ZapB Stimulates Z Ring Assembly and Cell Division

DEFF Research Database (Denmark)

Ebersbach, Gitte; Galli, Elizabeth; Møller-Jensen, Jakob

2008-01-01

Formation of the Z ring is the first known event in bacterial cell division. However, it is not yet known how the assembly and contraction of the Z ring is regulated. Here, we identify a novel cell division factor ZapB in Escherichia coli that simultaneously stimulates Z ring assembly and cell...... division. Deletion of zapB resulted in delayed cell division and the formation of ectopic Z rings and spirals whereas overexpression of ZapB resulted in nucleoid condensation and aberrant cell divisions. Localization of ZapB to the divisome depended on FtsZ but not FtsA, ZipA or FtsI and ZapB interacted...... with FtsZ in a bacterial two-hybrid analysis. The simultaneous inactivation of FtsA and ZipA prevented Z ring assembly and ZapB localization. Time lapse microscopy showed that ZapB-GFP is present at mid-cell in a pattern very similar to that of FtsZ. Cells carrying a zapB deletion and the ftsZ84ts allele...
Noise-induced Min phenotypes in E. coli.

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David Fange

2006-06-01

Full Text Available The spatiotemporal oscillations of the Escherichia coli proteins MinD and MinE direct cell division to the region between the chromosomes. Several quantitative models of the Min system have been suggested before, but no one of them accounts for the behavior of all documented mutant phenotypes. We analyzed the stochastic reaction-diffusion kinetics of the Min proteins for several E. coli mutants and compared the results to the corresponding deterministic mean-field description. We found that wild-type (wt and filamentous (ftsZ- cells are well characterized by the mean-field model, but that a stochastic model is necessary to account for several of the characteristics of the spherical (rodA- and phospathedylethanolamide-deficient (PE- phenotypes. For spherical cells, the mean-field model is bistable, and the system can get trapped in a non-oscillatory state. However, when the intrinsic noise is considered, only the experimentally observed oscillatory behavior remains. The stochastic model also reproduces the change in oscillation directions observed in the spherical phenotype and the occasional gliding of the MinD region along the inner membrane. For the PE- mutant, the stochastic model explains the appearance of randomly localized and dense MinD clusters as a nucleation phenomenon, in which the stochastic kinetics at low copy number causes local discharges of the high MinD(ATP to MinD(ADP potential. We find that a simple five-reaction model of the Min system can explain all documented Min phenotypes, if stochastic kinetics and three-dimensional diffusion are accounted for. Our results emphasize that local copy number fluctuation may result in phenotypic differences although the total number of molecules of the relevant species is high.
Determination of the prevalence of subclinical endometritis and evaluation of molecular characterization of Escherichia coli (E-coli separated of them in mares repeat breeder in Yazd province

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Taktaz Hafshejani Taghi

2016-11-01

Full Text Available Escherichia coli are known as the most common cause of reproductive tract infection in mare. Due to the progressive process of antibiotics use and increasing prevalence of antibiotic resistance, the aim of this study is evaluate the prevalence of subclinical endometritis and antibiotic resistance genes in Escherichia coli isolated. In this study, 60 mares were used with infertility background. Diagnosis of endometritis was performed using history and ultrasonography. Cytology, culture, Antibiogram were done of samples and PCR test was used to examine the gene virulence and antibiotic resistance. E-coli bacteria was isolated 48/33 % from sample culture. In PCR test 66/21 % of bacteria had virulence gene. It was determined, the lowest resistance to chloramphenicol about 38/15% and greatest resistance into ampicillin, tetracycline and streptomycin with 23/69 percent, respectively. 93% samples cytology had neutrophil more than two and the agent of 50% showed E. coli. The cause of half of subclinical endometritis in infertile maresis E-coli bacteriaEscherichia coli are known as the most common cause of reproductive tract infection in mare. Due to the progressive process of antibiotics use and increasing prevalence of antibiotic resistance, the aim of this study is evaluate the prevalence of subclinical endometritis and antibiotic resistance genes in Escherichia coli isolated. In this study, 60 mares were used with infertility background. Diagnosis of endometritis was performed using history and ultrasonography. Cytology, culture, Antibiogram were done of samples and PCR test was used to examine the gene virulence and antibiotic resistance. E-coli bacteria was isolated 48/33 % from sample culture. In PCR test 66/21 % of bacteria had virulence gene. It was determined, the lowest resistance to chloramphenicol about 38/15% and greatest resistance into ampicillin, tetracycline and streptomycin with 23/69 percent, respectively. 93% samples cytology had
Contribution of the Pmra Promoter to Expression of Genes in the Escherichia coli mra Cluster of Cell Envelope Biosynthesis and Cell Division Genes

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Mengin-Lecreulx, Dominique; Ayala, Juan; Bouhss, Ahmed; van Heijenoort, Jean; Parquet, Claudine; Hara, Hiroshi

1998-01-01

Recently, a promoter for the essential gene ftsI, which encodes penicillin-binding protein 3 of Escherichia coli, was precisely localized 1.9 kb upstream from this gene, at the beginning of the mra cluster of cell division and cell envelope biosynthesis genes (H. Hara, S. Yasuda, K. Horiuchi, and J. T. Park, J. Bacteriol. 179:5802–5811, 1997). Disruption of this promoter (Pmra) on the chromosome and its replacement by the lac promoter (Pmra::Plac) led to isopropyl-β-d-thiogalactopyranoside (IPTG)-dependent cells that lysed in the absence of inducer, a defect which was complemented only when the whole region from Pmra to ftsW, the fifth gene downstream from ftsI, was provided in trans on a plasmid. In the present work, the levels of various proteins involved in peptidoglycan synthesis and cell division were precisely determined in cells in which Pmra::Plac promoter expression was repressed or fully induced. It was confirmed that the Pmra promoter is required for expression of the first nine genes of the mra cluster: mraZ (orfC), mraW (orfB), ftsL (mraR), ftsI, murE, murF, mraY, murD, and ftsW. Interestingly, three- to sixfold-decreased levels of MurG and MurC enzymes were observed in uninduced Pmra::Plac cells. This was correlated with an accumulation of the nucleotide precursors UDP–N-acetylglucosamine and UDP–N-acetylmuramic acid, substrates of these enzymes, and with a depletion of the pool of UDP–N-acetylmuramyl pentapeptide, resulting in decreased cell wall peptidoglycan synthesis. Moreover, the expression of ftsZ, the penultimate gene from this cluster, was significantly reduced when Pmra expression was repressed. It was concluded that the transcription of the genes located downstream from ftsW in the mra cluster, from murG to ftsZ, is also mainly (but not exclusively) dependent on the Pmra promoter. PMID:9721276
Distribution of extended-spectrum cephalosporin resistance determinants in Salmonella enterica and Escherichia coli isolated from broilers in southern Japan.

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Shahada, F; Chuma, T; Kosugi, G; Kusumoto, M; Iwata, T; Akiba, M

2013-06-01

This study was conducted to investigate the distribution and diversity of extended-spectrum cephalosporin (ESC) resistance determinants in Salmonella enterica and Escherichia coli obtained from the same cecal samples and to provide evidence of transmission of the resistance determinants among these bacteria in broiler farms in southern Japan. Salmonella enterica and E. coli were characterized by serotyping and multilocus sequence typing, respectively. An antimicrobial susceptibility test, plasmid analysis, and identification and localization of resistance genes were performed to determine the relatedness of ESC resistance determinants among the isolates. Of 48 flocks examined, 14 had S. enterica. In total, 57 S. enterica isolates were obtained, 45 of which showed ESC resistance. Extended-spectrum cephalosporin-resistant E. coli were also obtained from all of these ESC-resistant Salmonella-positive samples. β-Lactamase genes, blaTEM-52 (38 isolates), blaCTX-M-14 (1 isolate), and blaCMY-2 (6 isolates), were carried by conjugative untypable or IncP plasmids detected in the S. enterica serovars Infantis and Manhattan. The β-lactamase genes blaCTX-M-14 (3 isolates), blaCTX-M-15 (3 isolates), blaSHV-2 (1 isolate), blaSHV-12 (2 isolates), and blaCMY-2 (32 isolates) associated with IncI1-Iγ, IncFIB, IncFIC, IncK, IncB/O, and IncY plasmids were detected in E. coli co-isolates. Restriction mapping revealed similar plasmids in Salmonella Infantis and Salmonella Manhattan and in different sequence types of E. coli. Intraspecies transmission of plasmids was suggested within S. enterica and E. coli populations, whereas interspecies transmission was not observed. This study highlights the importance of plasmids as carriers of ESC resistance determinants.
Computational determination of the effects of virulent Escherichia coli and salmonella bacteriophages on human gut.

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Mostafa, Marwa Mostafa; Nassef, Mohammad; Badr, Amr

2016-10-01

Salmonella and Escherichia coli are different types of bacteria that cause food poisoning in humans. In the elderly, infants and people with chronic conditions, it is very dangerous if Salmonella or E. coli gets into the bloodstream and then they must be treated by phage therapy. Treating Salmonella and E. coli by phage therapy affects the gut flora. This research paper presents a system for detecting the effects of virulent E. coli and Salmonella bacteriophages on human gut. A method based on Domain-Domain Interactions (DDIs) model is implemented in the proposed system to determine the interactions between the proteins of human gut bacteria and the proteins of bacteriophages that infect virulent E. coli and Salmonella. The system helps gastroenterologists to realize the effect of injecting bacteriophages that infect virulent E. coli and Salmonella on the human gut. By testing the system over Enterobacteria phage 933W, Enterobacteria phage VT2-Sa and Enterobacteria phage P22, it resulted in four interactions between the proteins of the bacteriophages that infect E. coli O157:H7, E. coli O104:H4 and Salmonella typhimurium and the proteins of human gut bacterium strains. Several effects were detected such as: antibacterial activity against a number of bacterial species in human gut, regulation of cellular differentiation and organogenesis during gut, lung, and heart development, ammonia assimilation in bacteria, yeasts, and plants, energizing defense system and its function in the detoxification of lipopolysaccharide, and in the prevention of bacterial translocation in human gut. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.
Isolating E.Coli Bacteriophage from Raw Sewage and Determining its Selectivity to the Host Cell

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SM Imeni

2016-05-01

Full Text Available Introduction: Bacteriophages are viruses that infect and destroy prokaryote cells, specifically the bacteria. They act too selective, so as each bacteriophage affects only on specific type of bacteria. Due to their specific features, bacteriophages can be used as an appropriate substitute for antibiotics in infectious diseases treatment. Therefore, this study aimed to isolate E. coli-specific bacteriophage from raw sewage. Methods: Eight samples of raw sewage, each containing approximately 50 ml of raw sewage with 10 minute gap, were prepared from Zargandeh wastewater treatment plant, Tehran, Iran. The sewages were mixed with Brain-heart infusion medium (BHI as a liquid culture medium in order to let the microorganisms grow. Incubation, purification and determination of bacteria were followed repeatedly to isolate the bacteriophage. Then it was tested on E.coli (ATCC 25922, Enterococcus faecalis (ATCC 19433, Staphylococcus aureus (ATCC 2392, and Yersinia enterocolitica (ATCC 9610 in order to determine the bacteriophage selectivity. Results: The E.coli bacteriophages were successfully isolated from all the eight samples, that were completely able to lyse and destroy E.coli bacterial cells, though no effect was observed on other types of bacteria. Conclusion: The study findings revealed that bacteriophages act selectively. Considering the raise of antibiotic resistance in the world, bacteriophages can serve as a good substitute for antibiotics in treating infectious diseases.
Antibacterial activity of 3-methylbenzo[d]thiazol-methylquinolinium derivatives and study of their action mechanism.

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Sun, Ning; Du, Ruo-Lan; Zheng, Yuan-Yuan; Guo, Qi; Cai, Sen-Yuan; Liu, Zhi-Hua; Fang, Zhi-Yuan; Yuan, Wen-Chang; Liu, Ting; Li, Xiao-Mei; Lu, Yu-Jing; Wong, Kwok-Yin

2018-12-01

The increasing incidence of multidrug resistant bacterial infection renders an urgent need for the development of new antibiotics. To develop small molecules disturbing FtsZ activity has been recognized as promising approach to search for antibacterial of high potency systematically. Herein, a series of novel quinolinium derivatives were synthesized and their antibacterial activities were investigated. The compounds show strong antibacterial activities against different bacteria strains including MRSA, VRE and NDM-1 Escherichia coli. Among these derivatives, a compound bearing a 4-fluorophenyl group (A2) exhibited a superior antibacterial activity and its MICs to the drug-resistant strains are found lower than those of methicillin and vancomycin. The biological results suggest that these quinolinium derivatives can disrupt the GTPase activity and dynamic assembly of FtsZ, and thus inhibit bacterial cell division and then cause bacterial cell death. These compounds deserve further evaluation for the development of new antibacterial agents targeting FtsZ.
Detection of coliform bacteria, determination of phylogenetic typing and antibiotic resistance profile of Escherichia coli in qanats and springs of East-Azerbaijan province

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N. Shabani Lokarani

2017-05-01

Full Text Available Escherichia coli as a fecal contamination and is considered as an index in water. The aim of this study was to determine the phenotypic and genotypic characteristics of E. coli and antibiotic resistance of the isolates collected from qanats and springs in East-Azerbaijan province. For this purpose, 118 samples were selected from above mentioned area and examined by MPN method. The positive coliform samples were identified by phenotypic and genotypic methods. Afterwards, to determine the genetic diversity of E. coli isolates, phylogenetic typing we conducted by means of multiplex PCR. To determine the antibiotic resistance profile, antibiotic discs of Nalidixic Acid, Co-trimoxazol, Amoxicillin, Gentamaicin Ciprofloxacin, Chloramphenicol, Imipenem, Cefotaxime and Ceftazidime antibiogram were used. Based on results, 48% of the samples were evaluated as positive for coliform including 40% for E. coli and 19% for Klebsiella. Amongst 23 isolates confirmed as E. coli by PCR. Phylogenetic typing revealed that 44% of E. coli strains belonged to type D and B2 and 56% belonged to A and B1 phylotypes. Antimicrobial susceptibility pattern showed that 92% of E. coli isolates were resistant to Amoxicillin. All E. coli isolates were sensitive to Imipenem. It was concluded that presence of pathogenic E. coli with high rate of antibacterial resistance in waters source could be considered as a human health hazard.
Fortuitous structure determination of ‘as-isolated’ Escherichia coli bacterioferritin in a novel crystal form

International Nuclear Information System (INIS)

Eerde, André van; Wolterink-van Loo, Suzanne; Oost, John van der; Dijkstra, Bauke W.

2006-01-01

E. coli bacterioferritin was crystallized in a novel crystal form from different conditions and the structure was solved. The crystals belonged to space group P2 1 3 and diffracted to a resolution of 2.5 Å. Escherichia coli bacterioferritin was serendipitously crystallized in a novel cubic crystal form and its structure could be determined to 2.5 Å resolution despite a high degree of merohedral twinning. This is the first report of crystallographic data on ‘as-isolated’ E. coli bacterioferritin. The ferroxidase active site contains positive difference density consistent with two metal ions that had co-purified with the protein. X-ray fluorescence studies suggest that the metal composition is different from that of previous structures and is a mix of zinc and native iron ions. The ferroxidase-centre configuration displays a similar flexibility as previously noted for other bacterioferritins
Peptidoglycan synthesis drives an FtsZ-treadmilling-independent step of cytokinesis.

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Monteiro, João M; Pereira, Ana R; Reichmann, Nathalie T; Saraiva, Bruno M; Fernandes, Pedro B; Veiga, Helena; Tavares, Andreia C; Santos, Margarida; Ferreira, Maria T; Macário, Vânia; VanNieuwenhze, Michael S; Filipe, Sérgio R; Pinho, Mariana G

2018-02-22

Peptidoglycan is the main component of the bacterial wall and protects cells from the mechanical stress that results from high intracellular turgor. Peptidoglycan biosynthesis is very similar in all bacteria; bacterial shapes are therefore mainly determined by the spatial and temporal regulation of peptidoglycan synthesis rather than by the chemical composition of peptidoglycan. The form of rod-shaped bacteria, such as Bacillus subtilis or Escherichia coli, is generated by the action of two peptidoglycan synthesis machineries that act at the septum and at the lateral wall in processes coordinated by the cytoskeletal proteins FtsZ and MreB, respectively. The tubulin homologue FtsZ is the first protein recruited to the division site, where it assembles in filaments-forming the Z ring-that undergo treadmilling and recruit later divisome proteins. The rate of treadmilling in B. subtilis controls the rates of both peptidoglycan synthesis and cell division. The actin homologue MreB forms discrete patches that move circumferentially around the cell in tracks perpendicular to the long axis of the cell, and organize the insertion of new cell wall during elongation. Cocci such as Staphylococcus aureus possess only one type of peptidoglycan synthesis machinery, which is diverted from the cell periphery to the septum in preparation for division. The molecular cue that coordinates this transition has remained elusive. Here we investigate the localization of S. aureus peptidoglycan biosynthesis proteins and show that the recruitment of the putative lipid II flippase MurJ to the septum, by the DivIB-DivIC-FtsL complex, drives peptidoglycan incorporation to the midcell. MurJ recruitment corresponds to a turning point in cytokinesis, which is slow and dependent on FtsZ treadmilling before MurJ arrival but becomes faster and independent of FtsZ treadmilling after peptidoglycan synthesis activity is directed to the septum, where it provides additional force for cell envelope

Prevalence and behavior of multidrug-resistant shiga toxin-producing Escherichia coli, enteropathogenic E. coli and enterotoxigenic E. coli on coriander.

Science.gov (United States)

Gómez-Aldapa, Carlos A; Segovia-Cruz, Jesús A; Cerna-Cortes, Jorge F; Rangel-Vargas, Esmeralda; Salas-Rangel, Laura P; Gutiérrez-Alcántara, Eduardo J; Castro-Rosas, Javier

2016-10-01

The prevalence and behavior of multidrug-resistant diarrheagenic Escherichia coli pathotypes on coriander was determined. One hundred coriander samples were collected from markets. Generic E. coli were determined using the most probable number procedure. Diarrheagenic E. coli pathotypes (DEPs) were identified using two multiplex polymerase chain reaction procedures. Susceptibility to sixteen antibiotics was tested for the isolated DEPs strains by standard test. The behavior of multidrug-resistant DEPs isolated from coriander was determined on coriander leaves and chopped coriander at 25°± 2 °C and 3°± 2 °C. Generic E. coli and DEPs were identified, respectively, in 43 and 7% of samples. Nine DEPs strains were isolated from positive coriander samples. The identified DEPs included Shiga toxin-producing E. coli (STEC, 4%) enterotoxigenic E. coli (ETEC, 2%) and enteropathogenic E. coli (EPEC, 1%). All isolated DEPs strains exhibited multi-resistance to antibiotics. On inoculated coriander leaves stored at 25°± 2 °C or 3°± 2 °C, no growth was observed for multidrug-resistant DEPs strains. However, multidrug-resistant DEPs strains grew in chopped coriander: after 24 h at 25° ± 2 °C, DEPs strains had grown to approximately 3 log CFU/g. However, at 3°± 2 °C the bacterial growth was inhibited. To the best of our knowledge, this is the first report of the presence and behavior of multidrug-resistant STEC, ETEC and EPEC on coriander and chopped coriander. Copyright © 2016 Elsevier Ltd. All rights reserved.
Purification, crystallization and structure determination of native GroEL from Escherichia coli lacking bound potassium ions

International Nuclear Information System (INIS)

Kiser, Philip D.; Lodowski, David T.; Palczewski, Krzysztof

2007-01-01

A 3.02 Å crystal structure of native GroEL from E. coli is presented. GroEL is a member of the ATP-dependent chaperonin family that promotes the proper folding of many cytosolic bacterial proteins. The structures of GroEL in a variety of different states have been determined using X-ray crystallography and cryo-electron microscopy. In this study, a 3.02 Å crystal structure of the native GroEL complex from Escherichia coli is presented. The complex was purified and crystallized in the absence of potassium ions, which allowed evaluation of the structural changes that may occur in response to cognate potassium-ion binding by comparison to the previously determined wild-type GroEL structure (PDB code http://www.rcsb.org/pdb/explore.do?structureId), in which potassium ions were observed in all 14 subunits. In general, the structure is similar to the previously determined wild-type GroEL crystal structure with some differences in regard to temperature-factor distribution
Combined protein construct and synthetic gene engineering for heterologous protein expression and crystallization using Gene Composer

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Walchli John

2009-04-01

Full Text Available Abstract Background With the goal of improving yield and success rates of heterologous protein production for structural studies we have developed the database and algorithm software package Gene Composer. This freely available electronic tool facilitates the information-rich design of protein constructs and their engineered synthetic gene sequences, as detailed in the accompanying manuscript. Results In this report, we compare heterologous protein expression levels from native sequences to that of codon engineered synthetic gene constructs designed by Gene Composer. A test set of proteins including a human kinase (P38α, viral polymerase (HCV NS5B, and bacterial structural protein (FtsZ were expressed in both E. coli and a cell-free wheat germ translation system. We also compare the protein expression levels in E. coli for a set of 11 different proteins with greatly varied G:C content and codon bias. Conclusion The results consistently demonstrate that protein yields from codon engineered Gene Composer designs are as good as or better than those achieved from the synonymous native genes. Moreover, structure guided N- and C-terminal deletion constructs designed with the aid of Gene Composer can lead to greater success in gene to structure work as exemplified by the X-ray crystallographic structure determination of FtsZ from Bacillus subtilis. These results validate the Gene Composer algorithms, and suggest that using a combination of synthetic gene and protein construct engineering tools can improve the economics of gene to structure research.
Effect of bile on growth, peritoneal absorption, and blood clearance of Escherichia coli in E coli peritonitis

International Nuclear Information System (INIS)

Andersson, R.; Schalen, C.; Tranberg, K.G.

1991-01-01

The effect of intraperitoneal bile on growth, peritoneal absorption, and clearance of Escherichia coli was determined in E coli peritonitis in the rat. In E coli peritonitis, intraperitoneal bacterial counts gradually decreased, whereas they increased (after 2 hours) with subsequent development of bacteremia in E coli plus bile peritonitis. After an intraperitoneal injection of labeled bacteria, blood radioactivity was only initially lower in E coli plus bile peritonitis compared with E coli peritonitis. Clearance from blood was lower in E coli plus bile peritonitis than in E coli peritonitis. Organ localization was similar in E coli peritonitis and E coli plus bile peritonitis with decreased splenic, increased pulmonary, and unchanged hepatic uptakes compared with controls. Impaired peritoneal absorption of bacteria, together with impaired local host defense, is likely to enhance the noxious effect of bile in E coli peritonitis
Antimicrobial resistance and resistance gene determinants in clinical Escherichia coli from different animal species in Switzerland.

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Lanz, Roland; Kuhnert, Peter; Boerlin, Patrick

2003-01-02

Antimicrobial susceptibility testing was performed on a total of 581 clinical Escherichia coli isolates from diarrhea and edema disease in pigs, from acute mastitis in dairy cattle, from urinary tract infections in dogs and cats, and from septicemia in laying hens collected in Switzerland between 1999 and 2001. Among the 16 antimicrobial agents tested, resistance was most frequent for sulfonamides, tetracycline, and streptomycin. Isolates from swine presented significantly more resistance than those from the other animal species. The distribution of the resistance determinants for sulfonamides, tetracycline, and streptomycin was assessed by hybridization and PCR in resistant isolates. Significant differences in the distribution of resistance determinants for tetracycline (tetA, tetB) and sulfonamides (sulII) were observed between the isolates from swine and those from the other species. Resistance to sulfonamides could not be explained by known resistance mechanisms in more than a quarter of the sulfonamide-resistant and sulfonamide-intermediate isolates from swine, dogs and cats. This finding suggests that one or several new resistance mechanisms for sulfonamides may be widespread among E. coli isolates from these animal species. The integrase gene (intI) from class I integrons was detected in a large proportion of resistant isolates in association with the sulI and aadA genes, thus demonstrating the importance of integrons in the epidemiology of resistance in clinical E. coli isolates from animals.
Identification and Partial Characterization of Potential FtsL and FtsQ Homologs of Chlamydia

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Scot P Ouellette

2015-11-01

Full Text Available Chlamydia is amongst the rare bacteria that lack the critical cell division protein FtsZ. By annotation, Chlamydia also lacks several other essential cell division proteins including the FtsLBQ complex that links the early (e.g. FtsZ and late (e.g. FtsI/Pbp3 components of the division machinery. Here, we report chlamydial FtsL and FtsQ homologs. Ct271 aligned well with E. coli FtsL and shared sequence homology with it, including a predicted leucine-zipper like motif. Based on in silico modeling, we show that Ct764 has structural homology to FtsQ in spite of little sequence similarity. Importantly, ct271/ftsL and ct764/ftsQ are present within all sequenced chlamydial genomes and are expressed during the replicative phase of the chlamydial developmental cycle, two key characteristics for a chlamydial cell division gene. GFP-Ct764 localized to the division septum of dividing transformed chlamydiae, and, importantly, over-expression inhibited chlamydial development. Using a bacterial two-hybrid approach, we show that Ct764 interacted with other components of the chlamydial division apparatus. However, Ct764 was not capable of complementing an E. coli FtsQ depletion strain in spite of its ability to interact with many of the same division proteins as E. coli FtsQ, suggesting that chlamydial FtsQ may function differently. We previously proposed that Chlamydia uses MreB and other rod-shape determining proteins as an alternative system for organizing the division site and its apparatus. Chlamydial FtsL and FtsQ homologs expand the number of identified chlamydial cell division proteins and suggest that Chlamydia has likely kept the late components of the division machinery while substituting the Mre system for the early components.
Associative Interactions in Crowded Solutions of Biopolymers Counteract Depletion Effects.

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Groen, Joost; Foschepoth, David; te Brinke, Esra; Boersma, Arnold J; Imamura, Hiromi; Rivas, Germán; Heus, Hans A; Huck, Wilhelm T S

2015-10-14

The cytosol of Escherichia coli is an extremely crowded environment, containing high concentrations of biopolymers which occupy 20-30% of the available volume. Such conditions are expected to yield depletion forces, which strongly promote macromolecular complexation. However, crowded macromolecule solutions, like the cytosol, are very prone to nonspecific associative interactions that can potentially counteract depletion. It remains unclear how the cytosol balances these opposing interactions. We used a FRET-based probe to systematically study depletion in vitro in different crowded environments, including a cytosolic mimic, E. coli lysate. We also studied bundle formation of FtsZ protofilaments under identical crowded conditions as a probe for depletion interactions at much larger overlap volumes of the probe molecule. The FRET probe showed a more compact conformation in synthetic crowding agents, suggesting strong depletion interactions. However, depletion was completely negated in cell lysate and other protein crowding agents, where the FRET probe even occupied slightly more volume. In contrast, bundle formation of FtsZ protofilaments proceeded as readily in E. coli lysate and other protein solutions as in synthetic crowding agents. Our experimental results and model suggest that, in crowded biopolymer solutions, associative interactions counterbalance depletion forces for small macromolecules. Furthermore, the net effects of macromolecular crowding will be dependent on both the size of the macromolecule and its associative interactions with the crowded background.
Prevalence of virulence determinants and antimicrobial resistance among commensal Escherichia coli derived from dairy and beef cattle.

Science.gov (United States)

Bok, Ewa; Mazurek, Justyna; Stosik, Michał; Wojciech, Magdalena; Baldy-Chudzik, Katarzyna

2015-01-19

Cattle is a reservoir of potentially pathogenic E. coli, bacteria that can represent a significant threat to public health, hence it is crucial to monitor the prevalence of the genetic determinants of virulence and antimicrobial resistance among the E. coli population. The aim of this study was the analysis of the phylogenetic structure, distribution of virulence factors (VFs) and prevalence of antimicrobial resistance among E. coli isolated from two groups of healthy cattle: 50 cows housed in the conventional barn (147 isolates) and 42 cows living on the ecological pasture (118 isolates). The phylogenetic analysis, identification of VFs and antimicrobial resistance genes were based on either multiplex or simplex PCR. The antimicrobial susceptibilities of E. coli were examined using the broth microdilution method. Two statistical approaches were used to analyse the results obtained for two groups of cattle. The relations between the dependent (VFs profiles, antibiotics) and the independent variables were described using the two models. The mixed logit model was used to characterise the prevalence of the analysed factors in the sets of isolates. The univariate logistic regression model was used to characterise the prevalence of these factors in particular animals. Given each model, the odds ratio (OR) and the 95% confidence interval for the population were estimated. The phylogroup B1 was predominant among isolates from beef cattle, while the phylogroups A, B1 and D occurred with equal frequency among isolates from dairy cattle. The frequency of VFs-positive isolates was significantly higher among isolates from beef cattle. E. coli from dairy cattle revealed significantly higher resistance to antibiotics. Some of the tested resistance genes were present among isolates from dairy cattle. Our study showed that the habitat and diet may affect the genetic diversity of commensal E. coli in the cattle. The results suggest that the ecological pasture habitat is related to
Role of endogeneous thiols in the determination of radio-resistance of E. coli B culture in different phases of its growth

Energy Technology Data Exchange (ETDEWEB)

Konstantinova, M M [AN SSSR, Moscow. Inst. Biologii Razvitiya

1975-05-01

An investigation was made of the link between the radioresistance of various stages of development of a culture of E. coli B with the level of sulfhydryl groups in the cells at each stage. The analysis was carried out by comparing the content of sulfhydryl groups in the cells, with their viability after irradiation and by determining the effectiveness of radio-protective and radio-sensitizing agents on a culture of various ages. It was shown that the thiols are the factor that determines the variation in radiosensitivity of a culture of E. coli B in the logarithmic and stationary phases of growth.
WGS accurately predicts antimicrobial resistance in Escherichia coli

Science.gov (United States)

Objectives: To determine the effectiveness of whole-genome sequencing (WGS) in identifying resistance genotypes of multidrug-resistant Escherichia coli (E. coli) and whether these correlate with observed phenotypes. Methods: Seventy-six E. coli strains were isolated from farm cattle and measured f...
Genetic Transfer of Salmonella typhimurium and Escherichia coli Lipopolysaccharide Antigens to Escherichia coli K-12

Science.gov (United States)

Jones, Randall T.; Koeltzow, Donald E.; Stocker, B. A. D.

1972-01-01

Escherichia coli K-12 ϰ971 was crossed with a smooth Salmonella typhimurium donor, HfrK6, which transfers early the ilv-linked rfa region determining lipopolysaccharide (LPS) core structure. Two ilv+ hybrids differing in their response to the LPS-specific phages FO and C21 were then crossed with S. typhimurium HfrK9, which transfers early the rfb gene cluster determining O repeat unit structure. Most recombinants selected for his+ (near rfb) were agglutinated by Salmonella factor 4 antiserum. Transfer of an F′ factor (FS400) carrying the rfb–his region of S. typhimurium to the same two ilv+ hybrids gave similar results. LPS extracted from two ilv+,his+, factor 4-positive hybrids contained abequose, the immunodominant sugar for factor 4 specificity. By contrast, his+ hybrids obtained from ϰ971 itself by similar HfrK9 and F′FS400 crosses were not agglutinated by factor 4 antiserum, indicating that the parental E. coli ϰ971 does not have the capacity to attach Salmonella O repeat units to its LPS core. It is concluded that the Salmonella rfb genes are expressed only in E. coli ϰ971 hybrids which have also acquired ilv-linked genes (presumably rfa genes affecting core structure or O-translocase ability, or both) from a S. typhimurium donor. When E. coli ϰ971 was crossed with a smooth E. coli donor, Hfr59, of serotype O8, which transfers his early, most his+ recombinants were agglutinated by E. coli O8 antiserum and lysed by the O8-specific phage, Ω8. This suggests that, although the parental E. coli K-12 strain ϰ971 cannot attach Salmonella-specific repeat units to its LPS core, it does have the capacity to attach E. coli O8-specific repeat units. PMID:4559827
Chromosomal features of Escherichia coli serotype O2:K2, an avian pathogenic E. coli.

Science.gov (United States)

Jørgensen, Steffen L; Kudirkiene, Egle; Li, Lili; Christensen, Jens P; Olsen, John E; Nolan, Lisa; Olsen, Rikke H

2017-01-01

Escherichia coli causing infection outside the gastrointestinal system are referred to as extra-intestinal pathogenic E. coli. Avian pathogenic E. coli is a subgroup of extra-intestinal pathogenic E. coli and infections due to avian pathogenic E. coli have major impact on poultry production economy and welfare worldwide. An almost defining characteristic of avian pathogenic E. coli is the carriage of plasmids, which may encode virulence factors and antibiotic resistance determinates. For the same reason, plasmids of avian pathogenic E. coli have been intensively studied. However, genes encoded by the chromosome may also be important for disease manifestation and antimicrobial resistance. For the E. coli strain APEC_O2 the plasmids have been sequenced and analyzed in several studies, and E. coli APEC_O2 may therefore serve as a reference strain in future studies. Here we describe the chromosomal features of E. coli APEC_O2. E. coli APEC_O2 is a sequence type ST135, has a chromosome of 4,908,820 bp (plasmid removed), comprising 4672 protein-coding genes, 110 RNA genes, and 156 pseudogenes, with an average G + C content of 50.69%. We identified 82 insertion sequences as well as 4672 protein coding sequences, 12 predicated genomic islands, three prophage-related sequences, and two clustered regularly interspaced short palindromic repeats regions on the chromosome, suggesting the possible occurrence of horizontal gene transfer in this strain. The wildtype strain of E. coli APEC_O2 is resistant towards multiple antimicrobials, however, no (complete) antibiotic resistance genes were present on the chromosome, but a number of genes associated with extra-intestinal disease were identified. Together, the information provided here on E. coli APEC_O2 will assist in future studies of avian pathogenic E. coli strains, in particular regarding strain of E. coli APEC_O2, and aid in the general understanding of the pathogenesis of avian pathogenic E. coli .
Determination of phylogenetic groups and antibiotic resistance pattern of Enterotoxigenic Escherishia coli isolates from diarrheoic cases in Bam City by PCR

Directory of Open Access Journals (Sweden)

Hesam Alizade

2015-04-01

Full Text Available Background and Aim: Purposes of this study were to determine the phylogenetic groups, prevalence of enterotoxigenic pathotype and antibiotic resistance of Escherichia coli (E. coli isolates from diarrheic cases in Bam city. Materials and Methods: In this study 155 E. coli were isolated from diarrheic samples in Bam city. Phylogenetic groups of isolates and enterotoxigenic pathotype were determined by detection of chuA, yjaA, TspE4C2 and ST, LT genes respectively. Results: One hundred fifty five examined isolates were distributed in phylogenetic groups: A (71.60%, B1 (3.22%, B2 (9.67% and D (15.48%. The genes for enterotoxigenic pathotype were detected in 52 isolates (33.54%, which ST gene were found in 29 isolates, LT in 16 isolates and LT, ST genes in 7 isolates. Twenty nine ST gene positive isolates were distributed in three phylogenetic groups A (48.28%, D (41.38% and B2 (10.34%. According to the antibiotic susceptibility tests maximum and minimum antibiotic resistance rate was against to trimethoprim/sulfamethoxazole (74.19% and ciprofloxacin and gentamycin (9.67%. Fifteen multiple antibiotic resistance patterns were detected in four phylogenetic groups. Conclusions: Escherichia coli isolates from enterotoxigenic pathotype have a considerable antibiotic resistance rate in Bam city and were distributed in different phylogenetic groups. Since a considerable number of isolates were negative for LT and ST genes, it is necessary to study the other virulence genes and their phylogenetic background in E. coli isolates from diarrheic cases in Bam city.
Multifactorial effects of ambient temperature, precipitation, farm management, and environmental factors determine the level of generic Escherichia coli contamination on preharvested spinach.

Science.gov (United States)

Park, Sangshin; Navratil, Sarah; Gregory, Ashley; Bauer, Arin; Srinath, Indumathi; Szonyi, Barbara; Nightingale, Kendra; Anciso, Juan; Jun, Mikyoung; Han, Daikwon; Lawhon, Sara; Ivanek, Renata

2015-04-01

A repeated cross-sectional study was conducted to identify farm management, environment, weather, and landscape factors that predict the count of generic Escherichia coli on spinach at the preharvest level. E. coli was enumerated for 955 spinach samples collected on 12 farms in Texas and Colorado between 2010 and 2012. Farm management and environmental characteristics were surveyed using a questionnaire. Weather and landscape data were obtained from National Resources Information databases. A two-part mixed-effect negative binomial hurdle model, consisting of a logistic and zero-truncated negative binomial part with farm and date as random effects, was used to identify factors affecting E. coli counts on spinach. Results indicated that the odds of a contamination event (non-zero versus zero counts) vary by state (odds ratio [OR] = 108.1). Odds of contamination decreased with implementation of hygiene practices (OR = 0.06) and increased with an increasing average precipitation amount (mm) in the past 29 days (OR = 3.5) and the application of manure (OR = 52.2). On contaminated spinach, E. coli counts increased with the average precipitation amount over the past 29 days. The relationship between E. coli count and the average maximum daily temperature over the 9 days prior to sampling followed a quadratic function with the highest bacterial count at around 24°C. These findings indicate that the odds of a contamination event in spinach are determined by farm management, environment, and weather factors. However, once the contamination event has occurred, the count of E. coli on spinach is determined by weather only. Copyright © 2015, American Society for Microbiology. All Rights Reserved.
Analysis of MreB interactors in Chlamydia reveals a RodZ homolog but fails to detect an interaction with MraY.

Science.gov (United States)

Ouellette, Scot P; Rueden, Kelsey J; Gauliard, Emilie; Persons, Logan; de Boer, Piet A; Ladant, Daniel

2014-01-01

Chlamydia is an obligate intracellular bacterial pathogen that has significantly reduced its genome in adapting to the intracellular environment. One class of genes for which the bacterium has few annotated examples is cell division, and Chlamydia lacks FtsZ, a central coordinator of the division apparatus. We have previously implicated MreB as a potential substitute for FtsZ in Chlamydia (Ouellette et al., 2012). Thus, to identify new chlamydial cell division components, we searched for proteins that interacted with MreB. We performed a small-scale screen using a Gateway® compatible version of the Bacterial Adenylate Cyclase Two Hybrid (BACTH) system, BACTHGW, to detect proteins interacting with chlamydial MreB and identified a RodZ (YfgA) homolog. The chlamydial RodZ aligns well with the cytoplasmic domain of E. coli RodZ but lacks the periplasmic domain that is dispensable for rod cell shape maintenance in E. coli. The expression pattern of yfgA/rodZ was similar to that of mreB and ftsI, suggesting that these genes may operate in a common functional pathway. The chlamydial RodZ correctly localized to the membrane of E. coli but was unable to complement an E. coli rodZ mutant strain, likely because of the inability of chlamydial RodZ to interact with the native E. coli MreB. Finally, we also tested whether chlamydial MreB could interact with MraY, as suggested by Gaballah et al. (2011). However, we did not detect an interaction between these proteins even when using an implementation of the BACTH system to allow native orientation of the N- and C-termini of MraY in the periplasm. Thus, further work will be needed to establish this proposed interaction. In sum, we have added to the repertoire of potential cell division proteins of Chlamydia.
Analysis of MreB interactors in Chlamydia reveals a RodZ homolog but fails to detect an interaction with MraY

Directory of Open Access Journals (Sweden)

Scot P Ouellette

2014-06-01

Full Text Available Chlamydia is an obligate intracellular bacterial pathogen that has significantly reduced its genome in adapting to the intracellular environment. One class of genes for which the bacterium has few annotated examples is cell division, and Chlamydia lacks FtsZ, a central coordinator of the division apparatus. We have previously implicated MreB as a potential substitute for FtsZ in Chlamydia (Ouellette et al., 2012. Thus, to identify new chlamydial cell division components, we searched for proteins that interacted with MreB. We performed a small-scale screen using a Gateway® compatible version of the Bacterial Adenylate Cyclase Two Hybrid (BACTH system, BACTHGW, to detect proteins interacting with chlamydial MreB and identified a RodZ (YfgA homolog. The chlamydial RodZ aligns well with the cytoplasmic domain of E. coli RodZ but lacks the periplasmic domain that is dispensable for rod cell shape maintenance in E. coli. The expression pattern of yfgA/rodZ was similar to that of mreB and ftsI, suggesting that these genes may operate in a common functional pathway. The chlamydial RodZ correctly localized to the membrane of E. coli but was unable to complement an E. coli rodZ mutant strain, likely because of the inability of chlamydial RodZ to interact with the native E. coli MreB. Finally, we also tested whether chlamydial MreB could interact with MraY, as suggested by Gaballah et al. (2011. However, we did not detect an interaction between these proteins even when using an implementation of the BACTH system to allow native orientation of the N- and C-termini of MraY in the periplasm. Thus, further work will be needed to establish this proposed interaction. In sum, we have added to the repertoire of potential cell division proteins of Chlamydia.
Acetyl-Phosphate Is a Critical Determinant of Lysine Acetylation in E. coli

DEFF Research Database (Denmark)

Weinert, Brian T; Iesmantavicius, Vytautas; Wagner, Sebastian A

2013-01-01

Lysine acetylation is a frequently occurring posttranslational modification in bacteria; however, little is known about its origin and regulation. Using the model bacterium Escherichia coli (E. coli), we found that most acetylation occurred at a low level and accumulated in growth-arrested cells...... acetylate lysine residues in vitro and that AcP levels are correlated with acetylation levels in vivo, suggesting that AcP may acetylate proteins nonenzymatically in cells. These results uncover a critical role for AcP in bacterial acetylation and indicate that most acetylation in E. coli occurs at a low...
Extensive and equivalent repair in both radiation-resistant and radiation-sensitive E. coli determined by a DNA-unwinding technique

International Nuclear Information System (INIS)

Ahnstroem, G.; George, A.M.; Cramp, W.A.

1978-01-01

The extent of strand breakage and repair in irradiated E. coli B/r and Bsub(s-l) was studied using a DNA-unwinding technique in denaturing conditions of weak alkali. Although these two strains showed widely different response to the lethal effects of ionizing radiation, they both had an equal capacity to repair radiation-induced breaks in DNA. Oxygen enhancement ratios for the killing of B/r and Bsub(s-l) were respectively 4 and 2; but after repair in non-nutrient or nutrient post-irradiation conditions, the oxygen enhancement values for the residual strand breaks were always the same for the two strains. The equal abilities of E.coli B/r and E.coli Bsub(s-l) to remove the strand breaks measured by this weak-alkali technqiue has led to the suggestion that some other type of damage to either DNA or another macromolecule may play a major role in determining whether or not the cells survive to proliferate. (author)
Extensive and equivalent repair in both radiation-resistant and radiation-sensitive E. coli determined by a DNA-unwinding technique

Energy Technology Data Exchange (ETDEWEB)

Ahnstroem, G [Stockholm Univ. (Sweden); George, A M; Cramp, W A

1978-10-01

The extent of strand breakage and repair in irradiated E. coli B/r and Bsub(s-l) was studied using a DNA-unwinding technique in denaturing conditions of weak alkali. Although these two strains showed widely different response to the lethal effects of ionizing radiation, they both had an equal capacity to repair radiation-induced breaks in DNA. Oxygen enhancement ratios for the killing of B/r and Bsub(s-l) were respectively 4 and 2; but after repair in non-nutrient or nutrient post-irradiation conditions, the oxygen enhancement values for the residual strand breaks were always the same for the two strains. The equal abilities of E.coli B/r and E.coli Bsub(s-l) to remove the strand breaks measured by this weak-alkali technqiue has led to the suggestion that some other type of damage to either DNA or another macromolecule may play a major role in determining whether or not the cells survive to proliferate.
Plasmid Conjugation in E. coli and Drug Resistance | Igwe ...

African Journals Online (AJOL)

This study aimed at determining the antibiotics susceptibility pattern of E. coli isolates claimed to be multidrug resistance using disc diffusion method. It also determined the presence of transferable resistance plasmids through conjugation and evaluated the medical significance of plasmid encoding E. coli and drug ...

Increased multi-drug resistant Escherichia coli from hospitals in ...

African Journals Online (AJOL)

Background: Multidrug-resistant Escherichia coli (MDR E. coli) has become a major public health concern in Sudan and many countries, causing failure in treatment with consequent huge health burden. Objectives: To determine the prevalence and susceptibility of MDR E. coli isolated from patients in hospitals at Khartoum ...
Characterization of Escherichia coli Phylogenetic Groups ...

African Journals Online (AJOL)

Background: Escherichia coli strains mainly fall into four phylogenetic groups (A, B1, B2, and D) and that virulent extra‑intestinal strains mainly belong to groups B2 and D. Aim: The aim was to determine the association between phylogenetic groups of E. coli causing extraintestinal infections (ExPEC) regarding the site of ...
ANALISIS CEMARAN BAKTERI Escherichia coli ANALISIS CEMARAN BAKTERI Escherichia coli ANALISIS CEMARAN BAKTERI Escherichia coli

OpenAIRE

ANGGREINI, RAHAYU

2015-01-01

2015 RAHAYU ANGGREINI coli Penelitian ini bertujuan untuk melakukan identifikasi cemaran bakteri E. coli O157:H7 pada daging sapi di kota Makassar. Sampel pada penelitian ini sebanyak 72 sampel Kata Kunci : Daging sapi, pasar tradisional, E. coli, E. coli O157:H7, kontaminasi bakteri, identifikasi E. coli O157:H7.
Protective effects of indigenous Escherichia coli against a pathogenic E. coli challenge strain in pigs.

Science.gov (United States)

Vahjen, W; Cuisiniere, T; Zentek, J

2017-10-13

To investigate the inhibitory effect of indigenous enterobacteria on pathogenic Escherichia coli, a challenge trial with postweaning pigs was conducted. A pathogenic E. coli strain was administered to all animals and their health was closely monitored thereafter. Faecal samples were taken from three healthy and three diarrhoeic animals. Samples were cultivated on MacConkey agar and isolates were subcultured. A soft agar overlay assay was used to determine the inhibitory activity of the isolates. A total of 1,173 enterobacterial isolates were screened for their ability to inhibit the E. coli challenge strain. Colony forming units of enterobacteria on MacConkey agar were not different between healthy and diarrhoeic animals in the original samples. Furthermore, numbers of isolates per animal were also not significantly different between healthy (482 isolates) and diarrhoeic animals (691 isolates). A total of 43 isolates (3.7%) with inhibitory activity against the pathogenic E. coli challenge strain were detected. All inhibitory isolates were identified as E. coli via MALDI-TOF. The isolates belonged to the phylotypes A, C and E. Many isolates (67.4%) were commensal E. coli without relevant porcine pathogenic factors, but toxin- and fimbrial genes (stx2e, fae, estIb, elt1a, fas, fan) were detected in 14 inhibitory isolates. Healthy animals showed significantly (P=0.003) more inhibitory isolates (36 of 482 isolates; 7.5%) than diseased animals (7 of 691 isolates; 1.0%). There were no significant correlations regarding phylotype or pathogenic factors between healthy and diseased animals. This study has shown that a small proportion of indigenous E. coli is able to inhibit in vitro growth of a pathogenic E. coli strain in pigs. Furthermore, healthy animals possess significantly more inhibitory E. coli strains than diarrhoeic animals. The inhibition of pathogenic E. coli by specific indigenous E. coli strains may be an underlying principle for the containment of pathogenic
Inactivation of E.coli in pre-cut mixed vegetables and S. typhimirium in mixed fruits by gamma radiation : Determination of D”10 Value

International Nuclear Information System (INIS)

Tolentino, Levelyn Mitos; De Guzman, Zenaida M.; Cobar, Ma. Lucia C.; Abrera, Gina B.; Diano, Gilbert T.

2015-01-01

Raw fruits and vegetables have been known to harbor pathogenic microorganisms such as Escherichia coli and Salmonella typhimurium. Associated diseases upon ingestion of contaminated fruits and vegetables include, but not limited to stomach cramps, diarrhea, vomiting and even kidney failure. Irradiation technology was proven to be an effective way of reducing and controlling pathogenic microorganisms in fruits and vegetables. The study was conducted to determine the D10 value of E.coli and S. typhimurium in pre-cut mixed vegetables and pre-cut mixed fruits, respectively, as an indicator of the effectiveness of gamma irradiation as an alternative treatment to improve the microbial safety and quality of fresh vegetables and fruits E. coli ATCC no.25922 and S. typhimurium ATCC No. 14028 were inoculated separately in ten (10) mL tryptic soy broth and incubated for 24 hrs at 37oC. Twenty five (25) grams of fresh pre-cut vegetables and pre-cut mixed fruits were inoculated separately with 0.5 mL cultured E. coli and 0.2 mL cultured S. typhimurium, respectively. The E. coli strains in fresh vegetable were exposed to irradiation doses of 0.2 to 0.8kGy. The samples were analyzed by making serial dilutions in sterile phosphate buffer using a petrifilm and tryptic soy agar according to the standards methodology describe in Bacteriological Analytical Manual (BAM). The D10 value of E. coli and S. typhimurium in fresh vegetables and mixed fruits were determined using linear regression analysis of the radiation dose with the log cfu/gm. The calculated D10 value ranged from 0.19 ± 0.02kGy and 0.22 ± 0.01kGy for pre-cut mixed vegetables and pre-cut mixed fruits, respectively. The results translate to irradiation dose of 1.0 kGy (5D10) to inactivate E. coli and S. typhimurium in mixed vegetables and fruits. (author)
Determination Pattern of Antibiotic Resistance in Entropathogenic Escherichia coli Strains Isolated from Children with Diarrhea

Directory of Open Access Journals (Sweden)

P. Karami

2012-04-01

Full Text Available Introduction & Objective: Diarrheal diseases are considered a major health problem, especially in children. Enteropathogenic Escherichia coli (EPEC strains are the common cause of diarrhea in children especially in developing countries. Because of undesirable effects of diarrhea and its interference with children's growth, in some cases antibiotic treatment is recommended. In recent years, resistance toward common and effective antibiotics in the treatment of infectious diseases became one of the most important challenges in medical society, for this purpose, antibiotic sensitivity and resistance of strains in every geographical zone must be determined. So in this study, of antibiotic patterns of these bacteria were examined.Materials & Methods: This cross-sectional study was performed on 192 strains of Enteropathogen Escherichia coli isolated from children who were suffering from diarrhea in 1389-1390 in the microbiology laboratory of Hamadan University of medical sciences. To identify these strains, standard biochemical and serology tests were used. The antibiotic sensitivity test of these isolates was carried out with disc diffusion agar method according to the CLSI standards for 14 different antibiotics disc. Resistance toward 3 or more than 3 classes of antibiotics were defined as multidrug resistance.Results: The result of this study shows EPEC strains had the highest resistance to cefpodoxime (97%, trimethoprim (60.7%, tetracycline (58.4% and ampicillin (45.8%. Multidrug resistance was 68.7 percent. These strains also showed the highest sensitivity against imipenem, ceftriaxone, and ciprofloxacin antibiotics.Conclusion: EPEC strains that were studied with resistance to ampicillin, tetracycline and convenient sensitivity against fluoroquinolones are one of the major factors in children’s diarrhea. A result of this research suggests that antimicrobial resistance in Escherichia coli strains are high and prescribing and antibiotic is not
Determining the Extremes of the Cellular NAD(H) Level by Using an Escherichia coli NAD+-Auxotrophic Mutant ▿

OpenAIRE

Zhou, Yongjin; Wang, Lei; Yang, Fan; Lin, Xinping; Zhang, Sufang; Zhao, Zongbao K.

2011-01-01

NAD (NAD+) and its reduced form (NADH) are omnipresent cofactors in biological systems. However, it is difficult to determine the extremes of the cellular NAD(H) level in live cells because the NAD+ level is tightly controlled by a biosynthesis regulation mechanism. Here, we developed a strategy to determine the extreme NAD(H) levels in Escherichia coli cells that were genetically engineered to be NAD+ auxotrophic. First, we expressed the ntt4 gene encoding the NAD(H) transporter in the E. co...
Fluorometric determination of ethidium bromide efflux kinetics in Escherichia coli

Directory of Open Access Journals (Sweden)

Monteiro Gabriel A

2009-10-01

Full Text Available Abstract Background Efflux pump activity has been associated with multidrug resistance phenotypes in bacteria, compromising the effectiveness of antimicrobial therapy. The development of methods for the early detection and quantification of drug transport across the bacterial cell wall is a tool essential to understand and overcome this type of drug resistance mechanism. This approach was developed to study the transport of the efflux pump substrate ethidium bromide (EtBr across the cell envelope of Escherichia coli K-12 and derivatives, differing in the expression of their efflux systems. Results EtBr transport across the cell envelope of E. coli K-12 and derivatives was analysed by a semi-automated fluorometric method. Accumulation and efflux of EtBr was studied under limiting energy supply (absence of glucose and low temperature and in the presence and absence of the efflux pump inhibitor, chlorpromazine. The bulk fluorescence variations were also observed by single-cell flow cytometry analysis, revealing that once inside the cells, leakage of EtBr does not occur and that efflux is mediated by active transport. The importance of AcrAB-TolC, the main efflux system of E. coli, in the extrusion of EtBr was evidenced by comparing strains with different levels of AcrAB expression. An experimental model was developed to describe the transport kinetics in the three strains. The model integrates passive entry (influx and active efflux of EtBr, and discriminates different degrees of efflux between the studied strains that vary in the activity of their efflux systems, as evident from the calculated efflux rates: = 0.0173 ± 0.0057 min-1; = 0.0106 ± 0.0033 min-1; and = 0.0230 ± 0.0075 min-1. Conclusion The combined use of a semi-automated fluorometric method and an experimental model allowed quantifying EtBr transport in E. coli strains that differ in their overall efflux activity. This methodology can be used for the early detection of differences in
Biochemical and serological characterization of Escherichia coli ...

African Journals Online (AJOL)

This study was designed to determine the isolation rate, serotypes and biochemical profiles of E. coli from colibacillosis and dead-in-shell embryos in Zaria, Northern-Nigeria. The isolation rate of E. coli from hatcheries studied were 4.67% and 7.50% from farms of Simtu Agricultural Company and National Animal Production ...
Thioredoxin from Escherichia coli

International Nuclear Information System (INIS)

Holmgren, A.; Ohlsson, I.; Grankvist, M.L.

1978-01-01

A competition radioimmunoassay for Escherichia coli thioredoxin using 125 I-labeled thioredoxin-S 2 and a double antibody technique was developed. The method permits determination of picomole amounts of thioredoxin in crude cell extracts and was used to study the localization of thioredoxin cell fractions. E. coli B was calculated to have approximately 10,000 copies of thioredoxin per cell mainly located in the soluble fraction after separation of the membrane and soluble fractions by gentle lysis and centrifugation. E. coli B tsnC mutants which are defective in the replication of phage T7 DNA in vivo and in vitro were examined for their content of thioredoxin. E. coli B tsnC 7004 contained no detectable level of thioredoxin in cell-free extracts examined under a variety of conditions. The results strongly suggest that tsnC 7004 is a nonsense or deletion mutant. Two other E. coli tsnC mutants, 7007 and 7008, contained detectable levels of thioredoxin in crude extracts as measured by thioredoxin reductase and gave similar immunoprecipitation reactions as the parent strain B/1. By radioimmunoassay incompletely cross-reacting material was present in both strains. These results show that tsnC 7007 and 7008 belong to a type of thioredoxin mutants with missence mutations in the thioredoxin gene affecting the function of thioredoxin as subunit in phage T7 DNA polymerase
Antimicrobial susceptibility patterns of E. coli from clinical sources in ...

African Journals Online (AJOL)

Background: Escherichia coli is the leading cause of urinary tract, ear, wound and other infections in humans. Increasing rates of antimicrobial resistance among E. coli is a growing concern worldwide. Objectives: The aim of this study was to determine the prevalence and antimicrobial susceptibility of E. coli from clinical ...
The determination of ground water quality based on the presence of Escherichia coli on populated area (a case study: Pasar Minggu, South Jakarta)

Science.gov (United States)

Rohmah, Y.; Rinanti, A.; Hendrawan, D. I.

2018-01-01

This study aims to determine the quality of groundwater in densely populated areas in the Pasar Minggu district, which focuses on examination of Escherichia coli bacteria as biological parameters. E.coli analysis was conducted in 3 sub-districtin the Pasar Minggu district, South Jakarta (106° 45‧0″E - 6° 15‧40″S), which included Pejaten Barat, Jati Padang and Kebagusan sub-district based on topography. The method used is Most Probable Number (MPN), referring to SNI 01-2332.1-2006. The results showed that the presence of E. coli in the highest groundwater ranged from 1100 MPN/100 ml to > 1100 MPN/100 ml, present in Pejaten Barat sub-district (06° 16‧39 "S-106° 49‧48" E) whereas the lowest number ranged from 11.5 MPN/100 ml to 23 MPN/100 ml occurred in Jati Padang sub-district (06° 17‧6 "S - 106° 49‧48" E).The correlation test results show that the amount of E.coli in ground water is affected by the distance of the septic tank to the groundwater well. The amount of E.coli contained in groundwater is also increasing, 1100 MPN/100 ml in groundwater samples at 15 m depth. This study provides information that topography and water flow affect the amount of E. coli.
Determinants of Antimicrobial Resistance in Escherichia coli Strains Isolated from Faeces and Urine of Women with Recurrent Urinary Tract Infections

NARCIS (Netherlands)

den Heijer, Casper D. J.; Beerepoot, Mariëlle A. J.; Prins, Jan M.; Geerlings, Suzanne E.; Stobberingh, Ellen E.

2012-01-01

For women with recurrent urinary tract infections (rUTI), the contribution of antibiotic use versus patient-related factors in determining the presence of antimicrobial resistance in faecal and urinary Escherichia coli, obtained from the same patient population, has not been assessed yet. Within the
Enteroaggregative Escherichia coli is the predominant diarrheagenic E. coli pathotype among irrigation water and food sources in South Africa.

Science.gov (United States)

Aijuka, Matthew; Santiago, Araceli E; Girón, Jorge A; Nataro, James P; Buys, Elna M

2018-08-02

Diarrheagenic E. coli (DEC) has been implicated in foodborne outbreaks worldwide and have been associated with childhood stunting in the absence of diarrhoea. Infection is extraordinarily common, but the routes of transmission have not been determined. Therefore, determining the most prevalent pathotypes in food and environmental sources may help provide better guidance to various stakeholders in ensuring food safety and public health and advancing understanding of the epidemiology of enteric disease. We characterized 205 E. coli strains previously isolated from producer distributor bulk milk (PDBM)(118), irrigation water (48), irrigated lettuce (29) and street vendor coleslaw (10) in South Africa. Enteropathogenic E. coli (EPEC), enterotoxigenic E. coli (ETEC), enteroaggregative E. coli (EAEC) and diffusely adherent E. coli (DAEC) were sought. We used PCR and partial gene sequencing for all 205 strains while 46 out of 205 that showed poor resolution were subsequently characterized using cell adherence (HeLa cells). PCR and partial gene sequencing of aatA and/or aaiC genes confirmed EAEC (2%, 5 out of 205) as the only pathotype. Phylogenetic analysis of sequenced EAEC strains with E. coli strains in GenBank showing ≥80% nucleotide sequence similarity based on possession of aaiC and aatA generated distinct clusters of strains separated predominantly based on their source of isolation (food source or human stool) suggesting a potential role of virulence genes in source tracking. EAEC 24%, 11 out of 46 strains (PDBM = 15%, irrigation water = 7%, irrigated lettuce = 2%) was similarly the predominant pathotype followed by strains showing invasiveness to HeLa cells, 4%, 2 out of 46 (PDBM = 2%, irrigated lettuce = 2%), among stains characterized using cell adherence. Therefore, EAEC may be the leading cause of DEC associated food and water-borne enteric infection in South Africa. Additionally, solely using molecular based methods targeting virulence
Antibiotic Resistance and Virulence Properties in Escherichia coli ...

African Journals Online (AJOL)

This study determined E. coli resistance to commonly used antibiotics together with their virulence properties in Ile-Ife, Nigeria. A total of 137 E. coli isolates from cases of urinary tract infection were tested for their sensitivity to commonly used antibiotics and possession of virulence factors using standard methods.
Immunochemical determination of cellular content of translation release factor RF4 in Escherichia coli

DEFF Research Database (Denmark)

Andersen, Lars Dyrskjøt; Manuel Palacios Moreno, Juan; Clark, Brian F. C.

1999-01-01

of the stop codons, and RF3 is known to accelerate the overall termination process. Release factor RF4 is a protein involved in the release of the mRNA and tRNA from the ribosomal complex. Furthermore, RF4 is involved in the proofreading in the elongation step of protein biosynthesis. The cellular contents...... of RF1, RF2, and RF3 were determined earlier. Here we report the cellular content of RF4 in Escherichia coli to be approximately 16,500 molecules per cell. The cells were grown in a rich medium and harvested in the beginning of the exponential growth phase. The quantifications were performed by using...
Determining the potential link between irrigation water quality and the microbiological quality of onions by phenotypic and genotypic characterization of Escherichia coli isolates.

Science.gov (United States)

du Plessis, Erika M; Duvenage, Francois; Korsten, Lise

2015-04-01

The potential transfer of human pathogenic bacteria present in irrigation water onto fresh produce was investigated, because surface water sources used for irrigation purposes in South Africa have increasingly been reported to be contaminated with enteric bacterial pathogens. A microbiological analysis was performed of a selected river in Limpopo Province, South Africa, that is often contaminated with raw sewage from municipal sewage works and overhead irrigated onions produced on a commercial farm. Counts of Escherichia coli, coliforms, aerobic bacteria, fungi, and yeasts and the prevalence of E. coli O157:H7, Salmonella, and Listeria monocytogenes were determined. Identities of bacterial isolates from irrigation water and onions were confirmed using matrix-assisted laser desorption ionization-time of flight mass spectrometry, PCR, and biochemical tests. To establish a potential link between the microbiological quality of the irrigation source and the onions, the E. coli isolates from both were subjected to antibiotic resistance, virulence gene, and enterobacterial repetitive intergenic consensus PCR analyses. River water E. coli counts exceeded South African Department of Water Affairs and World Health Organization irrigation water guidelines. Counts of aerobic bacteria, coliforms, fungi, and yeasts of onions from the market were acceptable according to Department of Health Directorate, Food Control, South Africa, microbiological guidelines for ready-to-eat fresh fruits and vegetables. E. coli O157:H7, Salmonella, and L. monocytogenes were not detected in onions, whereas only Salmonella was detected in 22% of water samples. Matrix-assisted laser desorption ionization-time of flight mass spectrometry and PCR identification of E. coli isolates from water and onions correlated. Of the 45 E. coli isolates from water and onions, 42.2% were resistant to multiple antibiotics. Virulence genes eae, stx1, and stx2 were detected in 2.2, 6.6, and 2.2% of the E. coli isolates
Diarrheagenic Escherichia coli and acute and persistent diarrhea in returned travelers

NARCIS (Netherlands)

Schultsz, C.; van den Ende, J.; Cobelens, F.; Vervoort, T.; van Gompel, A.; Wetsteyn, J. C.; Dankert, J.

2000-01-01

To determine the role of diarrheagenic Escherichia coli in acute and persistent diarrhea in returned travelers, a case control study was performed. Enterotoxigenic E. coli (ETEC) was detected in stool samples from 18 (10.7%) of 169 patients and 4 (3.7%) of 108 controls. Enteroaggregative E. coli
Transferability of antimicrobial resistance from multidrug-resistant Escherichia coli isolated from cattle in the USA to E. coli and Salmonella Newport recipients

Science.gov (United States)

The objective of this study was to evaluate conjugative transfer of cephalosporin resistance among (n=100) strains of multi-drug resistant Escherichia coli (MDRE) to Salmonella Newport and E. coli DH5-alpha recipients. To accomplish this, phenotypic and genotypic profiles were determined for MDRE, ...
Antibiotic resistance of Verotoxigenic Escherichia coli isolated from vegetables

Directory of Open Access Journals (Sweden)

mojtaba boniadian

2017-01-01

Full Text Available Introduction: Human gastrointestinal disease caused by verotoxigenic Escherichia coli has been diagnosed for recent decades. Escherichia coli O157:H7 is the most important serotype of verotoxigenic Escherichia coli that cause hemolytic uremic syndrome and hemorrhagic colitis in humans. This study was conducted to determine the occurrence of verotoxigenic E. coli and antibiotic resistance of the isolates from vegetables. Materials and methods: A total of 500 fresh vegetable samples were collected randomly from retail shops in Shahrekord, Iran. E. coli was isolated and identified using bacteriological and biochemical tests. PCR method was used to identify the rbfE, stx1, stx2 and eae genes. Also, antibiotic resistance of the isolates was determined by disk diffusion method. Results: The results represented that among 25 isolates possess virulence genes, 40, 12 and 4% of the isolates contained eaeA, STx2, and both genes, respectively. But none of them contained H7, STx1, and rfbE genes. The antibiotic resistance pattern demonstrated that the isolates were highly resistant to Gentamycin and cefotoxime. Discussion and conclusion: The results of this study showed that the presence of verotoxigenic E.coli in vegetables; and high resistance of the isolates to antibiotics could be hazardous for public health.

A murC gene from coryneform bacteria.

Science.gov (United States)

Wachi, M; Wijayarathna, C D; Teraoka, H; Nagai, K

1999-02-01

The upstream flanking region of the ftsQ and ftsZ genes of Brevibacterium flavum MJ233, which belongs to the coryneform bacteria, was amplified by the inverse polymerase chain reaction method and cloned in Escherichia coli. Complementation analysis of E. coli mutant with a defective cell-wall synthesis mechanism with the cloned fragment and its DNA sequencing indicated the presence of the murC gene, encoding UDP-N-acetylmuramate:L-alanine ligase involved in peptidoglycan synthesis, just upstream from the ftsQ gene. The B. flavum murC gene could encode a protein of 486 amino acid residues with a calculated molecular mass of 51 198 Da. A 50-kDa protein was synthesized by the B. flavum murC gene in an in vitro transcription/translation system using E. coli S30 lysate. These results indicate that the genes responsible for cell-wall synthesis and cell division are located as a cluster in B. flavum similar to the E. coli mra region.
Development of a Rapid Detection Method for Pathogenic E. Coli Group by Multiplex PCR and Determination of Profiles of Food Pathogens from Imported Seafood in the Republic of Korea

Energy Technology Data Exchange (ETDEWEB)

Kim, Changmin; Woo, Gunjo; Lee, Dongha; Park, Sunhee; Kwak, Hyosun; Kang, Yunsook; Park, Jongsuk; Lee, Soonho [Food Microbiology Division, the Republic of Korea Food and Drug Administration, Seoul (Korea, Republic of)

2005-01-15

A total of 347 samples of imported seafood products were purchased in retail markets, in order to determine their contamination with pathogenic bacteria: Staphylococcus aureus, Salmonella spp., Listeria monocytogenes, Vibrio parahaemoliycus, Escherichia coli and Escherichia coli 0157:H7. The results showed that 12,1% of the samples was positive to S. aureus and 2,1 % of the samples were contaminated with L. monocytogenes and E. coli. No Salmonella spp, V. parahaemolyticus and E. coli 0157:H7 were found. S. aureus was present in a wide variety of seafood products, being frozen shrimps the most contaminated one (29% of the frozen shrimps samples). L. monocytogenes was isolated only in smoked samples, whereas E. coli was found in smoked salmon as well as in frozen pollack flesh samples. (author)
Determining the Extremes of the Cellular NAD(H) Level by Using an Escherichia coli NAD+-Auxotrophic Mutant ▿

Science.gov (United States)

Zhou, Yongjin; Wang, Lei; Yang, Fan; Lin, Xinping; Zhang, Sufang; Zhao, Zongbao K.

2011-01-01

NAD (NAD+) and its reduced form (NADH) are omnipresent cofactors in biological systems. However, it is difficult to determine the extremes of the cellular NAD(H) level in live cells because the NAD+ level is tightly controlled by a biosynthesis regulation mechanism. Here, we developed a strategy to determine the extreme NAD(H) levels in Escherichia coli cells that were genetically engineered to be NAD+ auxotrophic. First, we expressed the ntt4 gene encoding the NAD(H) transporter in the E. coli mutant YJE001, which had a deletion of the nadC gene responsible for NAD+ de novo biosynthesis, and we showed NTT4 conferred on the mutant strain better growth in the presence of exogenous NAD+. We then constructed the NAD+-auxotrophic mutant YJE003 by disrupting the essential gene nadE, which is responsible for the last step of NAD+ biosynthesis in cells harboring the ntt4 gene. The minimal NAD+ level was determined in M9 medium in proliferating YJE003 cells that were preloaded with NAD+, while the maximal NAD(H) level was determined by exposing the cells to high concentrations of exogenous NAD(H). Compared with supplementation of NADH, cells grew faster and had a higher intracellular NAD(H) level when NAD+ was fed. The intracellular NAD(H) level increased with the increase of exogenous NAD+ concentration, until it reached a plateau. Thus, a minimal NAD(H) level of 0.039 mM and a maximum of 8.49 mM were determined, which were 0.044× and 9.6× those of wild-type cells, respectively. Finally, the potential application of this strategy in biotechnology is briefly discussed. PMID:21742902
Comparative analysis of virulence determinants, antibiotic susceptibility patterns and serogrouping of atypical enteropathogenic Escherichia coli versus typical enteropathogenic E. coli in India.

Science.gov (United States)

Malvi, Supriya; Appannanavar, Suma; Mohan, Balvinder; Kaur, Harsimran; Gautam, Neha; Bharti, Bhavneet; Kumar, Yashwant; Taneja, Neelam

2015-10-01

The epidemiology of enteropathogenic Escherichia coli (EPEC) and the significance of isolation of atypical EPEC (aEPEC) in childhood diarrhoea have not been well studied in an Indian context. A comparative study was undertaken to investigate virulence determinants, antibiotic susceptibility patterns and serogrouping of typical EPEC (tEPEC) versus aEPEC causing diarrhoea in children. A total of 400 prospective and 500 retrospective E. coli isolates were included. PCR was performed for eae, bfpA, efa, nleB, nleE, cdt, ehxA and paa genes. The Clinical and Laboratory Standards Institute's disc diffusion test was used to determine the antimicrobial susceptibility. Phenotypic screening of extended spectrum β-lactamases (ESBLs), AmpC and Klebsiella pneumoniae carbapenemase (KPC) production, and molecular detection of bla(NDM-1), bla(VIM), bla(CTX-M-15), bla(IMP) and bla(KPC) were performed. aEPEC (57.6 %) were more common as compared with tEPEC (42.3 %). The occurrence of virulence genes was observed to be three times higher in aEPEC as compared with tEPEC, efa1 (14.7 % of aEPEC, 4 % of tEPEC) being the most common. Most of the isolates did not belong to the classical EPEC O-serogroups. The highest resistance was observed against amoxicillin (93.22 %) followed by quinolones (83 %), cephalosporins (37.28 %), cotrimoxazole (35.59 %) and carbapenems (30.5 %). Overall equal numbers of aEPEC (41.17 %) and tEPEC (40 %) were observed to be multidrug-resistant. Fifteen EPEC strains demonstrated presence of ESBLs, five produced AmpC and four each produced metallo-β-lactamases and KPC-type carbapenemases; eight, seven and one isolate(s) each were positive for bla(VIM), bla(CTX-M-15) and bla(NDM-1), respectively. Here, to the best of our knowledge, we report for the first time on carbapenem resistance and the presence of bla(NDM-1) and bla(CTX-M-15) in EPEC isolates from India.
Escherichia coli pathotypes

Science.gov (United States)

Escherichia coli strains are important commensals of the intestinal tract of humans and animals; however, pathogenic strains, including diarrhea-inducing E. coli and extraintestinal pathogenic E. coli. Intestinal E. coli pathotypes may cause a dehydrating watery diarrhea, or more severe diseases su...
75 FR 14607 - Small Entity Compliance Guide: Bottled Water: Total Coliform and E. coli

Science.gov (United States)

2010-03-26

...] Small Entity Compliance Guide: Bottled Water: Total Coliform and E. coli; Availability AGENCY: Food and... the availability of a guidance for industry entitled ``Bottled Water: Total Coliform and E. coli... determine whether any of the coliform organisms are Escherichia coli (E. coli), an indicator of fecal...
Prevalence of Aeromonas species and Escherichia coli in stool ...

African Journals Online (AJOL)

Background: Diarrhoea is one of the main causes of mortality and morbidity in childhood. Bacterial diarrhoea is a common disorder. Aeromonas species and Escherichia coli (E. coli) are some of the aetiological agents associated with diarrhoea in children. Objective: To determine the prevalence of Aeromonas species and ...
Effects of irradiation on enzymes in E. coli

Energy Technology Data Exchange (ETDEWEB)

Geyer, H.

1962-08-15

To determine the effects of irradiation on enzymes in Escherichia coli strain Crookes, the influence of x radiation on the content of the coenzyme pyridoxal phosphate was investigated. The method of pyridoxal phosphate assay used was based on the fact that E. coli is able to produce tryptophanase. Enzyme activity was measured by determination of indole produced from tryptophane. Doses of 10,000 and 80,000 r of x radiation were given to resting cells and growing cells. It was found that pyridoxal phosphate production and content were not infiuenced by irradiation. (H.M.G.)
The K1 capsule is the critical determinant in the development of Escherichia coli meningitis in the rat.

OpenAIRE

Kim, K S; Itabashi, H; Gemski, P; Sadoff, J; Warren, R L; Cross, A S

1992-01-01

Although Escherichia coli strains possessing the K1 capsule are predominant among isolates from neonatal E. coli meningitis and most of these K1 isolates are associated with a limited number of 0 lipopolysaccharide (LPS) types, the basis of this association of K1 and certain 0 antigens with neonatal E. coli meningitis is not clear. The present study examined in experimental E. coli bacteremia and meningitis in newborn and adult rats whether or not the K1 capsule and/or O-LPS antigen are criti...
Escherichia coli O104 associated with human diarrhea, South Africa, 2004-2011.

Science.gov (United States)

Tau, Nomsa P; Meidany, Parastu; Smith, Anthony M; Sooka, Arvinda; Keddy, Karen H

2012-08-01

To determine the origin of >4,000 suspected diarrheagenic Escherichia coli strains isolated during 2004-2011 in South Africa, we identified 7 isolates as serotype O104; 5 as enteroaggregative E. coli O104:H4, and 2 as enteropathogenic E. coli O104:non-H4. Pulsed-field gel electrophoresis showed that these isolates were unrelated to the 2011 E. coli O104:H4 outbreak strain from Germany.
[Virulence markers of Escherichia coli O1 strains].

Science.gov (United States)

Makarova, M A; Kaftyreva, L A; Grigor'eva, N S; Kicha, E V; Lipatova, L A

2011-01-01

To detect virulence genes in clinical isolates of Escherichia coli O1 using polymerase chain reaction (PCR). One hundred and twenty strains of E.coli O1 strains isolated from faeces of patients with acute diarrhea (n = 45) and healthy persons (n = 75) were studied. PCR with primers for rfb and fliC genes, which control synthesis of O- and H- antigens respectively, was used. Fourteen virulence genes (pap, aaf, sfa, afa, eaeA, bfpA, ial, hly, cnf, stx1, stx2, lt, st, and aer) were detected by PCR primers. K1-antigen was determined by Pastorex Meningo B/E. coli O1 kit (Bio-Rad). rfb gene controlling O-antigen synthesis in serogroup O1 as well as fliC gene controlling synthesis of H7 and K1 antigens were detected in all strains. Thus all E. coli strains had antigenic structure O1:K1 :H-:F7. Virulence genes aafl, sfa, afa, eaeA, bfpA, ial, hly, cnf, stx1, stx2, lt, and st were not detected. All strains owned pap and aer genes regardless of the presence of acute diarrhea symptoms. It was shown that E. coli O1:KI:H-:F7 strains do not have virulence genes which are characteristic for diarrhea-causing Escherichia. In accordance with the presence of pap and aer genes they could be attributed to uropathogenic Escherichia (UPEC) or avian-pathogenic Escherichia (APEC). It is necessary to detect virulence factors in order to determine E. coli as a cause of intestinal infection.
ParA encoded on chromosome II of Deinococcus radiodurans binds ...

Indian Academy of Sciences (India)

2013-07-22

Jul 22, 2013 ... Introduction. Cell division ..... Subsequently, the level of total FtsZ (FtsZ + FtsZ-. YFP) in cells ... could affect the productive pattern of FtsZ localization and .... maintenance and disassembly of the Z ring. Nat. ... cation tolerance of plants sensitizes Deinococcus radiodurans ... metal shadowing and decoration.
Changes in Escherichia coli resistance to co-trimoxazole in ...

African Journals Online (AJOL)

In Thyolo district, Malawi, an operational research study is being conducted on the efficacy and feasibility of co-trimoxazole prophylaxis in preventing deaths in HIV-positive patients with tuberculosis (TB). A series of cross-sectional studies were carried out to determine i) whether faecal Escherichia coli (E.coli) resistance to ...
D10 value determination for Escherichia coli O157:H7 in different cultivations

International Nuclear Information System (INIS)

Oliveira, Sergio Eduardo M. de; Pires, Luis Fernando G.; Vital, Helio de C.

2002-01-01

Escherichia coli serum type O157:H7 is a highly pathogenic bacterium. Inside the human body, that microorganism causes a disease that leads to bloody diarrhea, stoppage of kidney functions and clots in the brain. That type of infection has been related to the consumption of different varieties of foods, mainly meat and other products of animal origin. Irradiation is an efficient method for elimination of pathogenic and spoiling microorganisms in foods. Thus, this work investigates the use of gamma irradiation for elimination of Escherichia coli O157:H7. For that purpose, inoculated samples in trypticase soy broth and saline solution 0,85% media were exposed to several gamma radiation doses. Counting the number of surviving bacteria yielded the following D 10 values for Escherichia coli O157:H7: 98±7 Gy, in trypticase soy broth and 49±4 Gy in saline solution 0,85% medium. (author)
Predictors Of Non-Escherichia Coli Urinary Tract Infection.

Science.gov (United States)

Shaikh, Nader; Wald, Ellen R; Keren, Ron; Gotman, Nathan; Ivanova, Anastasia; Carpenter, Myra A; Moxey-Mims, Marva; Hoberman, Alejandro

2016-11-01

We aimed to determine which children are prone to non-Escherichia coli urinary tract infection (UTIs). We included 769 children with UTI. We found that circumcised males, Hispanic children, children without fever and children with grades 3 and 4 vesicoureteral reflux were more likely to have a UTI caused by organisms other than E. coli. This information may guide clinicians in their choice of antimicrobial therapy.
British Escherichia coli O157 in Cattle Study (BECS): to determine the prevalence of E. coli O157 in herds with cattle destined for the food chain.

Science.gov (United States)

Henry, M K; Tongue, S C; Evans, J; Webster, C; McKENDRICK, I J; Morgan, M; Willett, A; Reeves, A; Humphry, R W; Gally, D L; Gunn, G J; Chase-Topping, M E

2017-11-01

Escherichia coli O157 are zoonotic bacteria for which cattle are an important reservoir. Prevalence estimates for E. coli O157 in British cattle for human consumption are over 10 years old. A new baseline is needed to inform current human health risk. The British E. coli O157 in Cattle Study (BECS) ran between September 2014 and November 2015 on 270 farms across Scotland and England & Wales. This is the first study to be conducted contemporaneously across Great Britain, thus enabling comparison between Scotland and England & Wales. Herd-level prevalence estimates for E. coli O157 did not differ significantly for Scotland (0·236, 95% CI 0·166-0·325) and England & Wales (0·213, 95% CI 0·156-0·283) (P = 0·65). The majority of isolates were verocytotoxin positive. A higher proportion of samples from Scotland were in the super-shedder category, though there was no difference between the surveys in the likelihood of a positive farm having at least one super-shedder sample. E. coli O157 continues to be common in British beef cattle, reaffirming public health policy that contact with cattle and their environments is a potential infection source.
E coli enteritis

Science.gov (United States)

... coli; Food poisoning - E. coli; E. coli diarrhea; Hamburger disease ... coleslaw or potato salad) that have been out of the refrigerator too ... reheated Fish or oysters Raw fruits or vegetables that have ...
Fluoroquinolone-resistant Escherichia coli carriage in long-term care facility.

Science.gov (United States)

Maslow, Joel N; Lee, Betsy; Lautenbach, Ebbing

2005-06-01

We conducted a cross-sectional study to determine the prevalence of, and risk factors for, colonization with fluoroquinolone (FQ)-resistant Escherichia coli in residents in a long-term care facility. FQ-resistant E. coli were identified from rectal swabs for 25 (51%) of 49 participants at study entry. On multivariable analyses, prior FQ use was the only independent risk factor for FQ-resistant E. coli carriage and was consistent for FQ exposures in the previous 3, 6, 9, or 12 months. Pulsed-field gel electrophoresis of FQ-resistant E. coli identified clonal spread of 1 strain among 16 residents. Loss (6 residents) or acquisition (7 residents) of FQ-resistant E. coli was documented and was associated with de novo colonization with genetically distinct strains. Unlike the case in the hospital setting, FQ-resistant E. coli carriage in long-term care facilities is associated with clonal spread.
Molecular detection and antimicrobial resistance of diarrheagenic Escherichia coli strains isolated from diarrheal cases

International Nuclear Information System (INIS)

Aslani, Mehdi M.; Salmanzadeh-Ahrabi, S.; Jafari, F.; Zali, Reza M.; Mani, M.; Alikhani, Yousef M.

2008-01-01

Objective was to identify and classify Iranian isolates of diarrheagenic Escherichia coli (E. coli) on the basis of presence of virulence genes and to determine antibiotic susceptibility of isolated strains. The current cross-sectional study was conducted in 2005 at the Pasteur Institute, Tehran, Iran. One hundred and ninety-three diarrheagenic E. coli isolated from diarrheal patients in different regions of Iran were included in current study. Virulence factors genees for diarrheagenic E. coli were detected by polymerase chain reaction. Of the 193 diarrheagenic E. coli detected by PCR, 86(44.5%) were Shiga toxin-producing E. coli (STEC), 74 (38.4%) enteropathogenic E. coli (EPEC), 19 (9.8%) enteroaggregative E. coli and 14 (7.3%) enterotoxigenic E. coli isolates. Susceptibility to 12 clinically important antimicrobial agents was determined for 193 strains of diarrhheagenic E. coli. A high incidence of resistance to tetracycline (63%), ampicillin (62%), streptomycin (56%), amoxicillin/clavulanic acid (44.5%), trimetoprim/sulphamethoxazole (39.5%) and cephalothin (37%) was observed. The STEC and EPEC strains with high resistance to tetracycline and ampicillin but highly susceptible to quinolones are among the most important causative agent of diarrhea in Iran. This study suggests that antimicrobial resistance is wide spread among E. coli strains colonizing Iranian patients. Guidelines for appropriate use of antibiotics in developing countries require updating. (author)
Identification of the Serratia marcescens hemolysin determinant by cloning into Escherichia coli

International Nuclear Information System (INIS)

Braun, V.; Neuss, B.; Ruan, Y.; Schiebel, E.; Schoeffler, H.; Jander, G.

1987-01-01

A cosmid bank of Serratia marcescens was established from which DNA fragments were cloned into the plasmid pBR322, which conferred the chromosomally encoded hemolytic activity to Escherichia coli K-12. By transposon mutagenesis with Tn1000 and Tn5 IS50/sub L/::phoA (TnphoA), the coding region was assigned to a DNA fragment, designated hyl, comprising approximately 7 kilobases. Two proteins with molecular weights of 61,000 (61K protein) and 160,000 (160K protein) were expressed by the pBR322 derivatives and by a plasmid which contained the hly genes under the control of a phage T7 promoter and the T7 RNA polymerase. When strongly overexpressed the 160K protein was released by E. coli cells into the extracellular medium concomitant with hemolytic activity. The genes encoding the 61K and the 160K proteins were transcribed in the same direction. Mutants expressing a 160K protein truncated at the carboxyl-terminal end were partially hemolytic. Hemolysis was progressively inhibited by saccharides with increasing molecular weights from maltotriose (M/sub r/ 504) to maltoheptaose (M/sub r/ 1152) and as totally abolished by dextran 4 (M/sub r/ 4000). This result and the observed influx of [ 14 C]sucrose into erythrocytes in the presence of hemolytic E. coli transformants under osmotically protective conditions suggest the formation of defined transmembrane channels by the hemolysin

The Escherichia coli transcriptome linked to growth fitness

Directory of Open Access Journals (Sweden)

Bei-Wen Ying

2016-03-01

Full Text Available A series of Escherichia coli strains with varied genomic sequences were subjected to high-density microarray analyses to elucidate the fitness-correlated transcriptomes. Fitness, which is commonly evaluated by the growth rate during the exponential phase, is not only determined by the genome but is also linked to growth conditions, e.g., temperature. We previously reported genetic and environmental contributions to E. coli transcriptomes and evolutionary transcriptome changes in thermal adaptation. Here, we describe experimental details on how to prepare microarray samples that truly represent the growth fitness of the E. coli cells. A step-by-step record of sample preparation procedures that correspond to growing cells and transcriptome data sets that are deposited at the GEO database (GSE33212, GSE52770, GSE61739 are also provided for reference. Keywords: Transcriptome, Growth fitness, Escherichia coli, Microarray
The presence of verotoxinogenic E. coli in some foods

Directory of Open Access Journals (Sweden)

Bostan K.

2005-01-01

Full Text Available In this study 30 samples each of ready-to-cook meatballs and white cheese as well as 96 samples of various ready-to-eat foods, obtained from different sales outlets in Istanbul, were analyzed for the presence of verotoxins (consequently vemtoxigenic E. coli E. coli with the aid of the enzyme immunoassay technique. Additionally, total coli-form and chromogenic E. coli count were determined by cultural methods for all food samples. E. coli growth was detected in all ready-to-cook meatballs (100%, in 27 of the white cheese samples (90% and in 69 of the other ready-to-eat food samples (71.9%. Verotoxins, however, could not be detected in any of the samples examined with the aid of the ELISA technique. The findings of this study indicate a low microbiological quality of the analyzed meatball, white cheese and ready-to-eat food samples; a considerable part of them did not conform to legal standards. However, within the sensitivity limits of the method applied no verotoxinogenic E. coli could be detected.
Molecular determination of extended spectrum b-lactamases antibiotics resistance genes in E.coli isolated from diarrhea in cattle

Directory of Open Access Journals (Sweden)

Ghassan Khudhair Ismaeel

2017-07-01

Full Text Available None response to the treatment by an antibiotic called antibiotics resistance result from some genes called resistance genes .This mechanism is widespread in most of the bacteria, like E.coli . All of the extended resistance genes called (ESBIS is a typical example for study of some genes that resistance beta-lactam antibiotic is subject of this research. Fifty feces sample were collected from cattle suffering from diarrhea in alqaissiyah city were cultured on selective media for E.coli , then DNA was extracted from all E.coli isolates for antibiotic resistance gene detection by PCR ; The results of this study revealed the prevalence of B-lactamase gene four B-lactamases genes in E.coli blaAmpc gene were (91.4%, the blactx-m gene were (80%, blaTem were (62.8% and finally and blaSHV gene were (22% among isolates E.coli ; blaAMPC gene has high prevalence than others genes while blaSHV was a lower percentage than other genes
Susceptibility of Escherichia coli and Enterococcus faecium isolated from pigs and broiler chickens to tetracycline degradation products and distribution of tetracycline resistance determinants in E-coli from food animals

DEFF Research Database (Denmark)

Sengeløv, G.; Halling-Sørensen, B.; Aarestrup, Frank Møller

2003-01-01

of tet(A) and tet(B) applied to all three animal species, and there was no difference between the distribution of tet(A) and tet(B) genes among non-pathogenic and pathogenic E. coli in any of the animal species. The susceptibility of 20 of these isolates together with 10 tetracycline sensitive E. coli......-anhydrochlortetracycline. In general both the tetracycline resistant and susceptible E. faecium were more susceptible to the compounds tested than E. coli. (C) 2003 Elsevier B.V.. All rights reserved....
Adsorption of Escherichia coli Using Bone Char | Rezaee | Journal ...

African Journals Online (AJOL)

The aim of study was providing a novel adsorbent for the removal of Escherichia coli (E.coli) as a microbial model from contaminated air especially in hospital units using bone char (BC). The BC was prepared from cattle animal bone by pyrolysis in a furnace at 450°C for 2 h. The characteristics of BC have been determined ...
Dynamics of CMY-2 producing E. coli in a broiler parent flock.

Science.gov (United States)

Dame-Korevaar, Anita; Fischer, Egil A J; Stegeman, Arjan; Mevius, Dik; van Essen-Zandbergen, Alieda; Velkers, Francisca; van der Goot, Jeanet

2017-05-01

Extended-spectrum β-lactamase and plasmid mediated AmpC β-lactamase (ESBL/pAmpC) producing bacteria are resistant to Extended Spectrum Cephalosporins (ESC), and are present in all levels of the broiler production chain. We determined the prevalence, concentration, and persistence of ESBL/pAmpC-Escherichia coli in a broiler parent flock during the rearing and laying period. One-day old chickens were housed in four separate pens. Until week 33 no antibiotics or coccidiostatics were used. During rearing 57 chickens in each pen (n=228), and in the laying period two groups of 33 chickens were individually sampled (n=66). Environmental samples were taken from week 16 onwards. ESBL/pAmpC-E. coli presence was determined by selective culturing. In the samples of week 16-19 the concentration of ESBL/pAmpC-E. coli was determined. All ESC-resistant isolates found were positive for pAmpC gene bla CMY-2 located on IncA/C plasmids, in several E. coli MLST types. CMY-2-E. coli prevalence decreased from 91% (95%CI 86-94%) at day 7 (week 1) to 0% (95%CI 0-5%) in week 21. However, CMY-2-E. coli remained present in the environmental samples during the whole study. CMY-2-E. coli concentration varied between detection limit (E. coli in this broiler parent flock in absence of antibiotics suggests a selective disadvantage of bla CMY-2 on IncA/C plasmids on animal level. The underlying mechanism should be studied further as this may provide new insights on how to reduce ESBL/pAmpC prevalence and transmission in the broiler production chain. Copyright © 2017 Elsevier B.V. All rights reserved.
Presence of non-O157 Shiga toxin-producing Escherichia coli, enterotoxigenic E. coli, enteropathogenic E. coli and Salmonella in fresh beetroot (Beta vulgaris L.) juice from public markets in Mexico.

Science.gov (United States)

Gómez-Aldapa, Carlos A; Rangel-Vargas, Esmeralda; Bautista-De León, Haydee; Castro-Rosas, Javier

2014-10-01

Unpasteurized juice has been associated with foodborne illness outbreaks for many years. Beetroot is a vegetable grown all over the world in temperate areas. In Mexico beetroot is consumed cooked in salads or raw as fresh unpasteurized juices. No data about the microbiological quality or safety of unpasteurized beetroot juices are available. Indicator bacteria, diarrheagenic Escherichia coli pathotypes (DEP) and Salmonella frequencies were determined for fresh unpasteurized beetroot juice from restaurants. One hundred unpasteurized beetroot juice samples were collected from public markets in Pachuca, Mexico. Frequencies in these samples were 100%, 75%, 53%, 9% and 4% of positive samples, for coliform bacteria, fecal coliforms, E. coli, DEP and Salmonella, respectively. Identified DEP included enterotoxigenic E. coli (ETEC), enteropathogenic E. coli (EPEC) and non-O157 Shiga toxin-producing E. coli (STEC). Identified Salmonella serotypes included Typhimurium and Enteritidis. This is the first report of microbiological quality and atypical EPEC, ETEC, non-O157 STEC and Salmonella isolation from fresh raw beetroot juice in Mexico. Fresh raw beetroot juice from markets is very probably an important factor contributing to the endemicity of atypical EPEC, ETEC, non-O157 STEC and Salmonella-related gastroenteritis in Mexico. © 2014 Society of Chemical Industry.
Cephalosporin-resistant Escherichia coli isolated from farm-workers and pigs in northern Vietnam

DEFF Research Database (Denmark)

Dang, Son T T; Bortolaia, Valeria; Thi, Nhat T

2018-01-01

OBJECTIVE Antimicrobial-resistant bacteria may be transmitted between farm workers and livestock. This study aimed to determine and compare the prevalence and the genetic determinants of cefotaxime-resistant and ESBL-producing Escherichia coli in faecal isolates from workers and pigs at 100 farms...... in northern Vietnam. METHODS Farmers were interviewed about antimicrobial usage in livestock. Escherichia coli isolated on MacConkey agar containing 2 mg/L of cefotaxime (CTX) were tested for susceptibility to different cephalosporins by disk diffusion and screened for occurrence of ESBL-encoding genes by PCR......% in pigs. In 76% of farms, CTX-resistant E. coli were shared by pigs and farm workers. ESBL-producing E. coli were detected from pigs and workers at 66 and 69 farms, respectively. The ESBL phenotype was mainly mediated by CTX-M and to a lesser extent by TEM. Occurrence of blaCTX-M was similar in E. coli...
E. Coli Infections

Science.gov (United States)

E. coli is the name of a type of bacteria that lives in your intestines. Most types of E. coli are harmless. However, some types can make you ... type causes travelers' diarrhea. The worst type of E. coli causes bloody diarrhea, and can sometimes cause kidney ...
Campylobacter coli in Swine Production: Antimicrobial Resistance Mechanisms and Molecular Epidemiology

OpenAIRE

Thakur, Siddhartha; Gebreyes, Wondwossen A.

2005-01-01

The aim of this study was to determine antimicrobial resistance, to evaluate and compare the use of two genotyping methods for molecular epidemiology purposes, and to determine the genotypic diversity of Campylobacter coli of porcine origin. A total of 100 C. coli isolates from swine were tested for susceptibility to six antimicrobials using the agar dilution method and genotyped using two high-resolution fingerprinting approaches: multilocus sequence typing (MLST) and pulsed-field gel electr...
Survival and activity of Streptococcus faecalis and Escherichia coli in tropical freshwater

Energy Technology Data Exchange (ETDEWEB)

Muniz, I.; Jimenez, L.; Toranzos, G.A.; Hazen, T.C. [Univ. of Puerto Rico, Rio Piedras (Puerto Rico)

1988-12-31

The survival of Streptococcus facecalis and Escherichia coli was studied in situ in a tropical rain forest watershed using membrane diffusion chambers. Densities were determined by acridine orange direct count and Coulter Counter. Population activity was determined by microautoradiography, cell respiration, and by nucleic acid composition. Densities of S. facecalis and E. coli decreased less than 1 log unit after 105 h as measured by direct count methods. Activity as measured by respiration, acridine orange activity, and microautoradiography indicated that both bacteria remained moderately active during the entire study. After 12 h, E. coli was more active than S. faecalis as measured by nucleic acid composition. E. coli and S. faecalis survived and remained active for more than 5 days. Consequently, both would seem to be unsuitable as indicators of recent fecal contamination in tropical waters.
Survival and activity of Streptococcus faecalis and escherichia coli in tropical freshwater

International Nuclear Information System (INIS)

Muniz, I; Toranzos, G.A.; Jimenez, L.; Hazen, T.C.

1989-01-01

The survival of Streptococcus faecalis and Escherichia coli was studied in situ in a tropical rain forest watershed using membrane diffusion chambers. Densities were determined by acridine orange direct count and Coulter Counter. Population activity was determined by microautoradiography, cell respiration, and by nucleic acid composition. Densities of S. faecalis and E. coli decreased less than 1 log unit after 105 hours as measured by direct count methods. Activity as measured by respiration, acridine orange activity, and microautoradiography indicated that both bacteria remained moderately active during the entire study. After 12 hours, E. coli was more active than S. faecalis as measured by nucleic acid composition. In this tropical rain forest watershed, E. coli and S. faecalis survived and remained active for more than 5 days; consequently, both would seem to be unsuitable as indicators of recent fecal contamination in tropical waters
INFLUENCE OF DOXORUBICIN ON ADHESIVE PROPERTIES OF E.COLI

Directory of Open Access Journals (Sweden)

O.G. Shapoval

2008-09-01

Full Text Available Influence ofantineoplastic drug doxorubicin and amikacin, the aminoglycoside family on adhesive activity of Escherichia coli was studied. Antimicrobialactivity(minimum inhibitory concentration-MIC ofboth drugs against experimental strains using serial two-fold dilution method was determined. Susceptibility of E.coli to amikacin in the presence of Sand j MIC doxorubicin was studied. After 10 passages in beef-extract broth with constant and increasing doxorubicin concentrations in the presence of Sand j MIC doxorubicin, the adhesive activity of initial and passage variants according to theirability to absorb human erythrocytes 1(0 Rh+ was determined. Itwas observed that experimental strains were susceptible to amikacin (MIC 1,5-6,2 mkg/ml butwere resistantto doxorubicin (MIC 1000 mkg/ml. Subinhibitory concentrations of this cytostatic (S and j MIC raised the sensitivity of experimental strains to amikacin and differently effected on adhesive activity of passage variants of E.coli.
Molecular epidemiology of extended-spectrum beta-lactamase-producing Escherichia coli

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Catherine Ludden

2014-09-01

Full Text Available Objectives: E. coli O25b-ST131 has disseminated worldwide in hospitals and the community. The objective of this study was to determine the extent to which E. coli O25b-ST131 accounts for extended-spectrum beta-lactamase (ESBLproducing E. coli from clinical samples from all sources in this region. Methods: Between January and June 2010 ESBL-producing E. coli were collected from 94 routine samples including 47 from residents of 25 nursing homes, 15 categorized as hospital acquired and 32 others. PCR was performed for detection of bla CTX-M, bla OXA-1, bla TEM, bla SHV and for the identification of members of the E. coli O25b:ST131 clonal group. PFGE was carried out using Xba I in accordance with PulseNet protocols. Results: The majority (97% of isolates harbored a bla CTX-M gene.E. coli O25b-ST131 accounted for 87% of all ESBL-producing E. coliand for 96% of isolates from nursing home residents. Conclusion:The E. coli O25b-ST131 clonal group predominated in the collection of ESBL-producing E. coli, particularly in nursing home isolates. J Microbiol Infect Dis 2014; 4(3: 92-96
E. Coli

Science.gov (United States)

... for the bacteria's medical name Escherichia coli . The strange thing about these bacteria — and lots of other ... In some cases, E. coli poisoning can cause life-threatening kidney problems. What Can Kids Do? Adults ...
Prevalence and antibiogram of Escherichia coli O157 isolated from ...

African Journals Online (AJOL)

E. coli O157 is an important serotype that caused many food borne outbreaks worldwide in the past decades. This study was carried out to estimate the prevalence and determine the antimicrobial susceptibility of E. coli O157 isolated from bovine carcasses and cecal contents at one abattoir in Jimma. A total of 300 samples ...
Chromosomal features of Escherichia coli serotype O2:K2, an avian pathogenic E. coli

DEFF Research Database (Denmark)

Jørgensen, Steffen L; Kudirkiene, Egle; Li, Lili

2017-01-01

Escherichia coli causing infection outside the gastrointestinal system are referred to as extra-intestinal pathogenic E. coli. Avian pathogenic E. coli is a subgroup of extra-intestinal pathogenic E. coli and infections due to avian pathogenic E. coli have major impact on poultry production econo...
Multiple Antibiotic Resistance Patterns of Escherichia coli Isolates from Swine Farms

OpenAIRE

Mathew, A. G.; Saxton, A. M.; Upchurch, W. G.; Chattin, S. E.

1999-01-01

Antibiotic resistance of Escherichia coli from sows and pigs was determined to compare patterns between pigs of various ages and degrees of antibiotic use. Resistance patterns differed between farm types and pigs of differing ages, indicating that pig age and degree of antibiotic use affect resistance of fecal E. coli.
Longitudinal study of transmission of Escherichia coli from broiler breeders to broilers

DEFF Research Database (Denmark)

Poulsen, Louise Ladefoged; Thoefner, Ida; Bisgaard, Magne

2017-01-01

of E. coli, isolated from broiler breeders with salpingitis, to the progeny and the possibility of subsequent first week mortality. Four parent flocks were followed during the whole production period (20-60 weeks) by post mortem and bacteriological examination of randomly selected dead birds. Newly...... selected for Pulsed-Field-Gel-Electrophoresis (PFGE) and Multi-Locus-Sequence-Typing (MLST) to determine their clonal relationships. E. coli was the main cause of both salpingitis in parents and first week mortality in broilers, and E. coli dominated the bacterial flora of the cloaca of newly hatched...... chickens. PFGE of E. coli showed identical band patterns in isolates from the three different sources indicating a transmission of E. coli from parent birds to chickens. In conclusion, E. coli isolated from salpingitis in broiler parents were found to be transmitted to broilers in which some sequence types...
Pathogenic Escherichia coli and food handlers in luxury hotels in Nairobi, Kenya.

Science.gov (United States)

Onyango, Abel O; Kenya, Eucharia U; Mbithi, John J N; Ng'ayo, Musa O

2009-11-01

The epidemiology and virulence properties of pathogenic Escherichia coli among food handlers in tourist destination hotels in Kenya are largely uncharacterized. This cross-sectional study among consenting 885 food handlers working in nine luxurious tourist hotels in Nairobi, Kenya determined the epidemiology, virulence properties, antibiotics susceptibility profiles and conjugation abilities of pathogenic Escherichia coli. Pathogenic Escherichia coli was detected among 39 (4.4%) subjects, including 1.8% enteroaggregative Escherichia coli (EAEC) harboring aggR genes, 1.2% enterotoxigenic Escherichia coli (ETEC) expressing both LT and STp toxins, 1.1% enteropathogenic Escherichia coli (EPEC) and 0.2% Shiga-like Escherichia coli (EHEC) both harboring eaeA and stx2 genes respectively. All the pathotypes had increased surface hydrophobicity. Using multivariate analyses, food handlers with loose stools were more likely to be infected with pathogenic Escherichia coli. Majority 53.8% of the pathotypes were resistant to tetracycline with 40.2% being multi-drug resistant. About 85.7% pathotypes trans-conjugated with Escherichia coli K12 F(-) NA(r) LA. The carriage of multi-drug resistant, toxin expressing pathogenic Escherichia coli by this population is of public health concern because exposure to low doses can result in infection. Screening food handlers and implementing public awareness programs is recommended as an intervention to control transmission of enteric pathogens.

Seroprevalence of Escherichia coli in traditional cheeses manufactured in Maragheh rural

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S Mahdavi

2014-11-01

Full Text Available Coliforms and Escherichia coli are major microbial indicators in the accessing the quality of foodstuffs. The presence of these bacteria in foods is considered as an indication of fecal contamination. E. coli O157:H7 is the most pathogenic strain that is transmitted to human through animal-foods. This study was performed on 100 traditional cheese samples manufactured in Maragheh rural to determine the seroprevalence of E. coli. The samples were analyzed with standard microbiological methods followed by biochemical confirmatory tests. Afterwards, the isolates were assayed for the detection of O-serotypes using direct agglutination method. Among the 100 cheese samples, E. coli O157serotypewas not detected in any sample. However, other E. coli serotypes including 32 isolates of non-O157 serotypes were detected. Among the isolates, enteropathogenic, enterotoxigenic and enterohaemorhhagic serogruops was also detected.
Quantitative Brightness Analysis of Fluorescence Intensity Fluctuations in E. Coli.

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Kwang-Ho Hur

Full Text Available The brightness measured by fluorescence fluctuation spectroscopy specifies the average stoichiometry of a labeled protein in a sample. Here we extended brightness analysis, which has been mainly applied in eukaryotic cells, to prokaryotic cells with E. coli serving as a model system. The small size of the E. coli cell introduces unique challenges for applying brightness analysis that are addressed in this work. Photobleaching leads to a depletion of fluorophores and a reduction of the brightness of protein complexes. In addition, the E. coli cell and the point spread function of the instrument only partially overlap, which influences intensity fluctuations. To address these challenges we developed MSQ analysis, which is based on the mean Q-value of segmented photon count data, and combined it with the analysis of axial scans through the E. coli cell. The MSQ method recovers brightness, concentration, and diffusion time of soluble proteins in E. coli. We applied MSQ to measure the brightness of EGFP in E. coli and compared it to solution measurements. We further used MSQ analysis to determine the oligomeric state of nuclear transport factor 2 labeled with EGFP expressed in E. coli cells. The results obtained demonstrate the feasibility of quantifying the stoichiometry of proteins by brightness analysis in a prokaryotic cell.
Chlamydia co-opts the rod shape-determining proteins MreB and Pbp2 for cell division.

Science.gov (United States)

Ouellette, Scot P; Karimova, Gouzel; Subtil, Agathe; Ladant, Daniel

2012-07-01

Chlamydiae are obligate intracellular bacterial pathogens that have extensively reduced their genome in adapting to the intracellular environment. The chlamydial genome contains only three annotated cell division genes and lacks ftsZ. How this obligate intracellular pathogen divides is uncharacterized. Chlamydiae contain two high-molecular-weight (HMW) penicillin binding proteins (Pbp) implicated in peptidoglycan synthesis, Pbp2 and Pbp3/FtsI. We show here, using HMW Pbp-specific penicillin derivatives, that both Pbp2 and Pbp3 are essential for chlamydial cell division. Ultrastructural analyses of antibiotic-treated cultures revealed distinct phenotypes: Pbp2 inhibition induced internal cell bodies within a single outer membrane whereas Pbp3 inhibition induced elongated phenotypes with little internal division. Each HMW Pbp interacts with the Chlamydia cell division protein FtsK. Chlamydiae are coccoid yet contain MreB, a rod shape-determining protein linked to Pbp2 in bacilli. Using MreB-specific antibiotics, we show that MreB is essential for chlamydial growth and division. Importantly, co-treatment with MreB-specific and Pbp-specific antibiotics resulted in the MreB-inhibited phenotype, placing MreB upstream of Pbp function in chlamydial cell division. Finally, we showed that MreB also interacts with FtsK. We propose that, in Chlamydia, MreB acts as a central co-ordinator at the division site to substitute for the lack of FtsZ in this bacterium. © 2012 Blackwell Publishing Ltd.
Genetic analysis of an Escherichia coli urease locus: evidence of DNA rearrangement.

OpenAIRE

Collins, C M; Falkow, S

1988-01-01

Ureolytic Escherichia coli strains are uncommon clinical isolates. The urease phenotype in a large percentage of these isolates is unstable and lost upon storage. We examined two urease-positive uropathogenic E. coli isolates that give off urease-negative segregants and determined that the urease phenotype was chromosomally encoded. The urease phenotype was cloned from E. coli 1021 and found to be encoded on a 9.4-kilobase HindIII restriction fragment. Transposon mutagenesis indicated that at...
E. Coli and Pregnancy

Science.gov (United States)

... chat Live Help Fact Sheets Share Escherichia coli (E. coli) Friday, 01 September 2017 In every pregnancy, a ... risk. This sheet talks about whether exposure to E. coli may increase the risk for birth defects over ...
Prodigiosin - A Multifaceted Escherichia coli Antimicrobial Agent.

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Tjaša Danevčič

Full Text Available Despite a considerable interest in prodigiosin, the mechanism of its antibacterial activity is still poorly understood. In this work, Escherichia coli cells were treated with prodigiosin to determine its antimicrobial effect on bacterial physiology. The effect of prodigiosin was concentration dependent. In prodigiosin treated cells above MIC value no significant DNA damage or cytoplasmic membrane disintegration was observed. The outer membrane, however, becomes leaky. Cells had severely decreased respiration activity. In prodigiosin treated cells protein and RNA synthesis were inhibited, cells were elongated but could not divide. Pre-treatment with prodigiosin improved E. coli survival rate in media containing ampicillin, kanamycin and erythromycin but not phleomycin. The results suggest that prodigiosin acts as a bacteriostatic agent in E. coli cells. If prodigiosin was diluted, cells resumed growth. The results indicate that prodigiosin has distinct mode of antibacterial action in different bacteria.
Detection of Escherichia Coli O157:H7 in Fecal Samples in Meat Goats

Science.gov (United States)

Mobley, Ray; Madden, Uford; Brooks-Walter, Alexis

2004-01-01

Studies have reported the isolation of Escherichia coli (E. coli)O157:H7 from pork, lamb and poultry products, and from other animals including deer, horses, dogs, birds and humans. There is limited or no information on the presence of the organism in goats. The objectives of this study were to determine if E. coli O157:H7 was naturally occurring…
Antimicrobial susceptibility of Escherichia coli from swine, horses, dogs and cats as determined in the BfT-GermVet monitoring program 2004-2006.

Science.gov (United States)

Grobbel, Mirjam; Lübke-Becker, Antina; Alesík, Eva; Schwarz, Stefan; Wallmann, Jürgen; Werckenthin, Christiane; Wieler, Lothar H

2007-01-01

A total of 417 isolates of Escherichia coli collected from five animal species/organ system combinations from swine [urinary/genital tract (UGT) incl. mastitis metritis agalactia syndrome], horses [genital tract (GT)] and dogs/cats [respiratory tract (RT), UGT and gastrointestinal tract (GIT)] were analysed quantitatively for their susceptibility against different antimicrobial agents by determination of minimum inhibitory concentrations. Regardless of which animal species the strains originated from, resistance appeared most frequently against sulfamethoxazole (18-59%), tetracycline (14-54 %), and ampicillin (14-39%). High percentages of intermediate isolates were observed for cephalothin (39-46 %). In general, low prevalences of resistance were detected for amoxicillin/clavulanic acid (1-4%), gentamicin (1-9%), and cefazolin (0-11%). Generally speaking, the antimicrobial resistance situation among E. coli isolates from horses and small animals is relatively good.
Triglyceride kinetics in fasted and fed E.coli septic rats

International Nuclear Information System (INIS)

Lanza-Jacoby, S.; Tabares, A.

1990-01-01

The mechanism for the development of hypertriglyceridemia during gram-negative sepsis was studies by examining the liver production and clearance of very-low-density lipoprotein (VLDL) triglyceride (TG). To assess the liver output and peripheral clearance the kinetics of VLDL-TG were determined by a constant intravenous infusion of [2- 3 H] glycerol-labeled VLDL in fasted control, fasted E. coli-treated, fed control, and fed E.coli-treated rats. Lewis inbred rats, 275-300 g, were made septic with 8 x 10 7 live E.coli colonies per 100 g body weight. Twenty-four hours following E.coli injection serum TG of fasted E.coli-treated rats was elevated by 170% which was attributed to a 67% decrease in the clearance rate of VLDL-TG in fasted E.coli-treated rats compared with their fasted controls. The secretion of VLDL-TG declined by 31% in the livers of the fasted E.coli-treated rats which was accompanied by a 2-fold increase in the composition of liver TG. In a second series of experiments control and E.coli-treated rats were fed intragastrically (IG) a balanced solution containing glucose plus fat as the sources of nonprotein calories. Serum TG were 26% lower in the fed E.coli-treated rats because the clearance rate increased by 86%. The secretion of TG in the fed septic rats increased by 40% but this difference was not significant. In the septic rat the ability to clear triglycerides from the plasma depends upon the nutritional state
Human Meningitis-Associated Escherichia coli

Science.gov (United States)

KIM, KWANG SIK

2016-01-01

E. coli is the most common Gram-negative bacillary organism causing meningitis and E. coli meningitis continues to be an important cause of mortality and morbidity throughout the world. Our incomplete knowledge of its pathogenesis contributes to such mortality and morbidity. Recent reports of E. coli strains producing CTX-M-type or TEM-type extended-spectrum β-lactamases create a challenge. Studies using in vitro and in vivo models of the blood-brain barrier have shown that E. coli meningitis follows a high-degree of bacteremia and invasion of the blood-brain barrier. E. coli invasion of the blood-brain barrier, the essentials step in the development of E. coli meningitis, requires specific microbial and host factors as well as microbe- and host-specific signaling molecules. Blockade of such microbial and host factors contributing to E. coli invasion of the blood-brain barrier is shown to be efficient in preventing E. coli penetration into the brain. The basis for requiring a high-degree of bacteremia for E. coli penetration of the blood-brain barrier, however, remains unclear. Continued investigation on the microbial and host factors contributing to a high-degree of bacteremia and E. coli invasion of the blood-brain barrier is likely to identify new targets for prevention and therapy of E. coli meningitis. PMID:27223820
Diarrheagenic Escherichia coli Markers and Phenotypes among Fecal E. coli Isolates Collected from Nicaraguan Infants ▿

OpenAIRE

Reyes, Daniel; Vilchez, Samuel; Paniagua, Margarita; Colque-Navarro, Patricia; Weintraub, Andrej; Möllby, Roland; Kühn, Inger

2010-01-01

We analyzed the prevalence of diarrheagenic Escherichia coli (DEC) markers and common phenotypes in 2,164 E. coli isolates from 282 DEC-positive samples. Enteropathogenic E. coli (EPEC) and enteroaggregative E. coli (EAEC) were very diverse and were not correlated with diarrhea. Enterotoxigenic E. coli (ETEC) estA and enterohemorrhagic E. coli (EHEC) belonged to a few phenotypes and were significantly correlated with diarrhea.
Fluoroquinolone Resistance Mechanisms in an Escherichia coli Isolate, HUE1, Without Quinolone Resistance-Determining Region Mutations

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Toyotaka eSato

2013-05-01

Full Text Available Fluoroquinolone resistance can cause major clinical problems. Here, we investigated fluoroquinolone resistance mechanisms in a clinical Escherichia coli isolate, HUE1, which had no mutations quinolone resistance-determining regions (QRDRs of DNA gyrase and topoisomerase IV. HUE1 demonstrated MICs that exceeded the breakpoints for ciprofloxacin, levofloxacin, and norfloxacin. HUE1 harbored oqxAB and qnrS1 on distinct plasmids. In addition, it exhibited lower intracellular ciprofloxacin concentrations and higher mRNA expression levels of efflux pumps and their global activators than did reference strains. The genes encoding AcrR (local AcrAB repressor and MarR (MarA repressor were disrupted by insertion of the transposon IS3-IS629 and a frameshift mutation, respectively. A series of mutants derived from HUE1 were obtained by plasmid curing and gene knockout using homologous recombination. Compared to the MICs of the parent strain HUE1, the fluoroquinolone MICs of these mutants indicated that qnrS1, oqxAB, acrAB, acrF, acrD, mdtK, mdfA, and tolC contributed to the reduced susceptibility to fluoroquinolone in HUE1. Therefore, fluoroquinolone resistance in HUE1 is caused by concomitant acquisition of QnrS1 and OqxAB and overexpression of AcrAB−TolC and other chromosome-encoded efflux pumps. Thus, we have demonstrated that QRDR mutations are not absolutely necessary for acquiring fluoroquinolone resistance in E. coli.
Multiple loci affecting photoreactivation in Escherichia coli

International Nuclear Information System (INIS)

Sutherland, B.M.; Hausrath, S.G.

1979-01-01

Sutherland et al. mapped a phr gene in Escherichia coli at 17 min and found that induction of an E. coli stain lysogenic for a lambda phage carrying this gene increased photoreactivating enzyme levels 2,000-fold. Recently, Smith and Youngs and Sancar and Rupert located a phr gene at 15.9 min. We have therefore investigated the properties of photoreactivating enzyme and cellular photoreactivation in cells containing deletions of the gene at 17 min. Cells with this deletion photoreactivated ultraviolet-induced killing at a rate 20% of normal; they also contained approximately 20% of the normal photoreactivating enzyme level. The residual enzyme in these cells was characterized to determine whether the reduced cellular photoreactivation rate and photoreactivating enzyme levels resulted from reduced numbers of normal enzymes or from an altered enzyme. Photoreactivating enzymes from strains carrying a deletion of the region at 17 min has an apparent K/sub m/ about two- to threefold higher than normal enzyme and showed markedly increased heat lability. The gene at 17 min thus contains information determining the function of the E. coli photoreactivating enzyme rather than the quantity of the enzyme. It is proposed that the gene at 17 min be termed phrA and that located at 15.9 min be termed phrB
DNA fingerprinting approaches to trace Escherichia coli sharing between dogs and owners.

Science.gov (United States)

Naziri, Z; Derakhshandeh, A; Firouzi, R; Motamedifar, M; Shojaee Tabrizi, A

2016-02-01

To determine the prevalence of cross-species sharing of Escherichia coli between healthy dogs and humans living in the same household. Two faecal E. coli isolates from 25 healthy dog-owner pairs and 16 healthy control humans were tested using three fingerprinting methods. The prevalence of within-household sharing of E. coli was 4, 8 and 8% using pulsed-field gel electrophoresis, randomly amplified polymorphic DNA and enterobacterial repetitive intergenic consensus-PCR analyses respectively. Within-household bacterial sharing was more prevalent than across-household sharing (P fingerprinting techniques will help to find ways for reducing the economic impact of E. coli infections. This study support claims that public health concerns regarding the cross-species sharing of E. coli are warranted but this risk is minimal. © 2015 The Society for Applied Microbiology.
Markerless Escherichia coli rrn Deletion Strains for Genetic Determination of Ribosomal Binding Sites

DEFF Research Database (Denmark)

Quan, Selwyn; Skovgaard, Ole; McLaughlin, Robert E

2015-01-01

Single-copy rrn strains facilitate genetic ribosomal studies in Escherichia coli. Consecutive markerless deletion of rrn operons resulted in slower growth upon inactivation of the fourth copy, which was reversed by supplying transfer RNA genes encoded in rrn operons in trans. Removal of the sixth...
Incidence of Escherichia coli  - Glucuronidase Positive on Goat Milk

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Zorica Voşgan

2016-11-01

Full Text Available Papers on beta- glucuronidase sensitivity and specificity for identifying Escherichia coli in sources of environment, food, water, etc. have been published since 1976. In this study we conducted a review of the incidence of E. coli β- glucuronidase -positive in goat milk, obtained by hand milking throughout the lactation: spring, summer, autumn. The presence of E. coli in milk is considered both as a health indicator and a pathogenic factor capable of causing food poisoning. The determination of the E. coli β-glucuronidase-positive was carried using TBX medium by cultivating colonies typical blue at 440C. The absence of E. coli in milk yielded during the spring, when the animal milking is done three times a day, was found in the performed analyses; the same was observed during fall, when the milk production is lower and the milking is done once a day. The load of E. coli β-glucuronidase-positive was averaging 66.67 CFU/ml of goat milk, during the middle lactation period (July-August, in conditions of higher temperature. During this period, milking is done in the mountain zone, where the transhumance of animals takes place in summer. The presence of the species E. coli was also confirmed by microscopic examination. Attention should be paid to hygiene and milk should be immediately cooled, during hot weather, as E. coli can be a source of food poisoning.
Quantitative real-time PCR technique for the identification of E. coli residual DNA in streptokinase recombinant product.

Science.gov (United States)

Fazelahi, Mansoureh; Kia, Vahid; Kaghazian, Hooman; Paryan, Mahdi

2017-11-26

Recombinant streptokinase is a biopharmaceutical which is usually produced in E. coli. Residual DNA as a contamination and risk factor may remain in the product. It is necessary to control the production procedure to exclude any possible contamination. The aim of the present study was to develop a highly specific and sensitive quantitative real-time PCR-based method to determine the amount of E. coli DNA in recombinant streptokinase. A specific primers and a probe was designed to detect all strains of E. coli. To determine the specificity, in addition to using NCBI BLASTn, 28 samples including human, bacterial, and viral genomes were used. The results confirmed that the assay detects no genomic DNA but E. coli's and the specificity was determined to be 100%. To determine the sensitivity and limit of detection of the assay, a 10-fold serial dilution (10 1 to 10 7 copies/µL) was tested in triplicate. The sensitivity of the test was determined to be 101 copies/µL or 35 fg/µL. Inter-assay and intra-assay were determined to be 0.86 and 1.69%, respectively. Based on the results, this assay can be used as an accurate method to evaluate the contamination of recombinant streptokinase in E. coli.
Conjugation in Escherichia coli

Science.gov (United States)

Boyer, Herbert

1966-01-01

Boyer, Herbert (Yale University, New Haven, Conn.). Conjugation in Escherichia coli. J. Bacteriol. 91:1767–1772. 1966.—The sex factor of Escherichia coli K-12 was introduced into an E. coli B/r strain by circumventing the host-controlled modification and restriction incompatibilities known to exist between these closely related strains. The sexual properties of the constructed F+ B strain and its Hfr derivatives were examined. These studies showed that the E. coli strain B/r F+ and Hfr derivatives are similar to the E. coli strain K-12 F+ and Hfr derivatives. However, the site of sex factor integration was found to be dependent on the host genome. PMID:5327905
E. coli Surface Properties Differ between Stream Water and Sediment Environments

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Xiao Liang

2016-11-01

Full Text Available The importance of E. coli as an indicator organism in fresh water has led to numerous studies focusing on cell properties and transport behavior. However, previous studies have been unable to assess if differences in E. coli cell surface properties and genomic variation are associated with different environmental habitats. In this study, we investigated the variation in characteristics of E. coli obtained from stream water and stream bottom sediments. Cell properties were measured for 77 genomically different E. coli strains (44 strains isolated from sediments and 33 strains isolated from water under common stream conditions in the Upper Midwestern United States: pH 8.0, ionic strength 10mM and 22˚C. Measured cell properties include hydrophobicity, zeta potential, net charge, total acidity and extracellular polymeric substance (EPS composition. Our results indicate that stream sediment E. coli had significantly greater hydrophobicity, greater EPS protein content and EPS sugar content, less negative net charge, and higher point of zero charge than stream water E. coli. A significant positive correlation was observed between hydrophobicity and EPS protein for stream sediment E. coli but not for stream water E. coli. Additionally, E. coli surviving in the same habitat tended to have significantly larger (GTG5 genome similarity. After accounting for the intrinsic impact from the genome, environmental habitat was determined to be a factor influencing some cell surface properties, such as hydrophobicity. The diversity of cell properties and its resulting impact on particle interactions should be considered for environmental fate and transport modeling of aquatic indicator organisms such as E. coli.
E. coli Surface Properties Differ between Stream Water and Sediment Environments.

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Liang, Xiao; Liao, Chunyu; Thompson, Michael L; Soupir, Michelle L; Jarboe, Laura R; Dixon, Philip M

2016-01-01

The importance of E. coli as an indicator organism in fresh water has led to numerous studies focusing on cell properties and transport behavior. However, previous studies have been unable to assess if differences in E. coli cell surface properties and genomic variation are associated with different environmental habitats. In this study, we investigated the variation in characteristics of E. coli obtained from stream water and stream bottom sediments. Cell properties were measured for 77 genomically different E. coli strains (44 strains isolated from sediments and 33 strains isolated from water) under common stream conditions in the Upper Midwestern United States: pH 8.0, ionic strength 10 mM and 22°C. Measured cell properties include hydrophobicity, zeta potential, net charge, total acidity, and extracellular polymeric substance (EPS) composition. Our results indicate that stream sediment E. coli had significantly greater hydrophobicity, greater EPS protein content and EPS sugar content, less negative net charge, and higher point of zero charge than stream water E. coli . A significant positive correlation was observed between hydrophobicity and EPS protein for stream sediment E. coli but not for stream water E. coli . Additionally, E. coli surviving in the same habitat tended to have significantly larger (GTG) 5 genome similarity. After accounting for the intrinsic impact from the genome, environmental habitat was determined to be a factor influencing some cell surface properties, such as hydrophobicity. The diversity of cell properties and its resulting impact on particle interactions should be considered for environmental fate and transport modeling of aquatic indicator organisms such as E. coli .

Factors affecting Escherichia coli concentrations at Lake Erie public bathing beaches

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Francy, Donna S.; Darner, Robert A.

1998-01-01

The environmental and water-quality factors that affect concentrations of Escherichia coli (E. coli) in water and sediment were investigated at three public bathing beachesEdgewater Park, Villa Angela, and Sims Parkin the Cleveland, Ohio metropolitan area. This study was done to aid in the determination of safe recreational use and to help water- resource managers assess more quickly and accurately the degradation of recreational water quality. Water and lake-bottom sediments were collected and ancillary environmental data were compiled for 41 days from May through September 1997. Water samples were analyzed for E. coli concentrations, suspended sediment concentrations, and turbidity. Lake- bottom sediment samples from the beach area were analyzed for E. coli concentrations and percent dry weight. Concentrations of E. coli were higher and more variable at Sims Park than at Villa Angela or Edgewater Park; concentrations were lowest at Edgewater Park. Time-series plots showed that short-term storage (less than one week) of E. coli in lake-bottom sediments may have occurred, although no evidence for long-term storage was found during the sampling period. E. coli concentrations in water were found to increase with increasing wave height, but the resuspension of E. coli from lake-bottom sediments by wave action could not be adequately assessed; higherwave heights were often associated with the discharge of sewage containing E. coli during or after a rainfall and wastewater-treatment plant overflow. Multiple linear regression (MLR) was used to develop models to predict recreational water quality at the in water. The related variables included turbidity, antecedent rainfall, antecedent weighted rainfall, volumes of wastewater-treatment plant overflows and metered outfalls (composed of storm-water runoff and combined-sewer overflows), a resuspension index, and wave heights. For the beaches in this study, wind speed, wind direction, water temperature, and the prswimmers
Cemaran Mikroba Escherichia coli dan Total Bakteri Koliform pada Air Minum Isi Ulang

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Rolan Sudirman Pakpahan

2015-05-01

there is no guarantee that refill drinking water quality meets any requirement every time. Results of refill drinking water sample in Kupang City in 2013 showed the water was 37.5% contaminated by microbes. This study aimed to analyze microbial contamination and determine determinants of Escherichia coli (E. coli and total Coliform on refill drinking water. This study used cross sectional design on January - March 2015. The population was 51 depots determined using total sampling technique. Data analysis was conducted in univariate, bivariate using simple logistic regression test and multivariate using multiple logistic regression test. Results showed drinking water contaminated by microbes worth 26 depots (51%, by E. coli 33.33% and by total Coliform 51%. Microbial contamination determinants using bivariate were knowledge (p value = 0.01 and behavior of operator (p value = 0.05. Meanwhile, microbial contamination determinants conducting multivariate were knowledge (p value = 0.026, hygiene of operator (p value = 0.05 and depot sanitation (p value = 0.044. Most dominating variables influencing microbial contamination are knowledge, operator’s hygiene and depot sanitation.
Biocompatible click chemistry enabled compartment-specific pH measurement inside E. coli.

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Yang, Maiyun; Jalloh, Abubakar S; Wei, Wei; Zhao, Jing; Wu, Peng; Chen, Peng R

2014-09-19

Bioorthogonal reactions, especially the Cu(I)-catalysed azide-alkyne cycloaddition, have revolutionized our ability to label and manipulate biomolecules under living conditions. The cytotoxicity of Cu(I) ions, however, has hindered the application of this reaction in the internal space of living cells. By systematically surveying a panel of Cu(I)-stabilizing ligands in promoting protein labelling within the cytoplasm of Escherichia coli, we identify a highly efficient and biocompatible catalyst for intracellular modification of proteins by azide-alkyne cycloaddition. This reaction permits us to conjugate an environment-sensitive fluorophore site specifically onto HdeA, an acid-stress chaperone that adopts pH-dependent conformational changes, in both the periplasm and cytoplasm of E. coli. The resulting protein-fluorophore hybrid pH indicators enable compartment-specific pH measurement to determine the pH gradient across the E. coli cytoplasmic membrane. This construct also allows the measurement of E. coli transmembrane potential, and the determination of the proton motive force across its inner membrane under normal and acid-stress conditions.
Genetic & virulence profiling of ESBL-positive E. coli from nosocomial & veterinary sources.

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Tyrrell, J M; Wootton, M; Toleman, M A; Howe, R A; Woodward, M; Walsh, T R

2016-04-15

CTX-M genes are the most prevalent ESBL globally, infiltrating nosocomial, community and environmental settings. Wild and domesticated animals may act as effective vectors for the dissemination of CTX-producing Enterobacteriaceae. This study aimed to contextualise blaCTX-M-14-positive, cephalosporin-resistant Enterobacteriaceae human infections and compared resistance and pathogenicity markers with veterinary isolates. Epidemiologically related human (n=18) and veterinary (n=4) blaCTX-M-14-positive E. coli were fully characterised. All were typed by XbaI pulsed field gel electrophoresis and ST. Chromosomal/plasmidic locations of blaCTX-M-14 were deduced by S1-nuclease digestion, and association with ISEcp1 was investigated by sequencing. Conjugation experiments assessed transmissibility of plasmids carrying blaCTX-M-14. Presence of virulence determinants was screened by PCR assay and pathogenicity potential was determined by in vitro Galleria mellonella infection models. 84% of clinical E. coli originated from community patients. blaCTX-M-14 was found ubiquitously downstream of ISEcp1 upon conjugative plasmids (25-150 kb). blaCTX-M-14 was also found upon the chromosome of eight E. coli isolates. CTX-M-14-producing E. coli were found at multiple hospital sites. Clonal commonality between patient, hospitals and livestock microbial populations was found. In vivo model survival rates from clinical isolates (30%) and veterinary isolates (0%) were significantly different (pE. coli involving community patients and farm livestock. blaCTX-M-14 positive human clinical isolates carry a lower intrinsic pathogenic potential than veterinary E. coli highlighting the need for greater veterinary practices in preventing dissemination of MDR E. coli among livestock. Copyright © 2016. Published by Elsevier B.V.
Molecular typing of uropathogenic E. coli strains by the ERIC-PCR method.

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Ardakani, Maryam Afkhami; Ranjbar, Reza

2016-04-01

Escherichia coli (E. coli) is the most common cause of urinary infections in hospitals. The aim of this study was to evaluate the ERIC-PCR method for molecular typing of uropathogenic E. coli strains isolated from hospitalized patients. In a cross sectional study, 98 E. coli samples were collected from urine samples taken from patients admitted to Baqiyatallah Hospital from June 2014 to January 2015. The disk agar diffusion method was used to determine antibiotic sensitivity. DNA proliferation based on repetitive intergenic consensus was used to classify the E. coli strains. The products of proliferation were electrophoresed on 1.5% agarose gel, and their dendrograms were drawn. The data were analyzed by online Insillico software. The method used in this research proliferated numerous bands (4-17 bands), ranging from 100 to 3000 base pairs. The detected strains were classified into six clusters (E1-E6) with 70% similarity between them. In this study, uropathogenic E. coli strains belonged to different genotypic clusters. It was found that ERIC-PCR had good differentiation power for molecular typing of uropathogenic E. coli strains isolated from the patients in the study.
Antibiotic Resistance in Escherichia coli from Pigs in Organic and Conventional Farming in Four European Countries

DEFF Research Database (Denmark)

Österberg, Julia; Wingstrand, Anne; Jensen, Annette Nygaard

2016-01-01

content and/or faeces from individual pigs was determined. In all four countries the percentage resistance to ampicillin, streptomycin, sulphonamides or trimethoprim was significantly lower in E. coli from organic pigs. In France and Italy, the percentage of isolates resistant to chloramphenicol...... in organic slaughter pigs in Denmark, France, Italy and Sweden. Samples were taken from the colon content and/or faeces and minimum inhibitory concentrations (MIC) of ten antibiotics were determined in isolates of Escherichia coli. In addition, the proportion of tetracycline (TET) resistant E. coli in colon...
Escherichia coli-Derived Uracil Increases the Antibacterial Activity and Growth Rate of Lactobacillus plantarum.

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Ha, Eun-Mi

2016-05-28

Lactobacillus plantarum (L. plantarum) is a representative probiotic. In particular, L. plantarum is the first commensal bacterium to colonize the intestine of infants. For this reason, the initial settlement of L. plantarum can play an important role in determining an infant's health as well as their eventual health status as an adult. In addition, L. plantarum combats pathogenic infections (such as Escherichia coli (E. coli), one of the early pathogenic colonizers in an unhealthy infant gut) by secreting antimicrobial substances. The aim of this research was to determine how L. plantarum combats E. coli infection and why it is a representative probiotic in the intestine. Consequently, this research observed that E. coli releases uracil. L. plantarum specifically recognizes E. coli-derived uracil, which increases the growth rate and production of antimicrobial substance of L. plantarum. In addition, through the inhibitory activity test, this study postulates that the antimicrobial substance is a protein and can be considered a bacteriocin-like substance. Therefore, this research assumes that L. plantarum exerts its antibacterial ability by recognizing E. coli and increasing its growth rate as a result, and this phenomenon could be one of the reasons for L. plantarum settling in the intestine of infants as a beneficial bacterium.
Adhesion of Escherichia coli onto quartz, hematite and corundum: extended DLVO theory and flotation behavior.

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Farahat, Mohsen; Hirajima, Tsuyoshi; Sasaki, Keiko; Doi, Katsumi

2009-11-01

The adhesion of Escherichia coli onto quartz, hematite and corundum was experimentally investigated. A strain of E. coli was used that had the genes for expressing protein for silica precipitation. The maximum cell adhesion was observed at pH mineral adhesion was assessed by the extended DLVO theory approach. The essential parameters for calculation of microbe-mineral interaction energy (Hamaker constants and acid-base components) were experimentally determined. The extended DLVO approach could be used to explain the results of the adhesion experiments. The effect of E. coli on the floatability of three oxide minerals was determined and the results showed that E. coli can act as a selective collector for quartz at acidic pH values, with 90% of the quartz floated at 1.5 x 10(9)cells/ml. However, only 9% hematite and 30% corundum could be floated under similar conditions. By using E. coli and no reagents, it was possible to separate quartz from a hematite-quartz mixture with Newton's efficiency of 0.70. Removal of quartz from the corundum mixture was achieved by E. coli with Newton's efficiency of 0.62.
The Escherichia coli BtuE protein functions as a resistance determinant against reactive oxygen species.

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Felipe A Arenas

2011-01-01

Full Text Available This work shows that the recently described Escherichia coli BtuE peroxidase protects the bacterium against oxidative stress that is generated by tellurite and by other reactive oxygen species elicitors (ROS. Cells lacking btuE (ΔbtuE displayed higher sensitivity to K(2TeO(3 and other oxidative stress-generating agents than did the isogenic, parental, wild-type strain. They also exhibited increased levels of cytoplasmic reactive oxygen species, oxidized proteins, thiobarbituric acid reactive substances, and lipoperoxides. E. coli ΔbtuE that was exposed to tellurite or H(2O(2 did not show growth changes relative to wild type cells either in aerobic or anaerobic conditions. Nevertheless, the elimination of btuE from cells deficient in catalases/peroxidases (Hpx(- resulted in impaired growth and resistance to these toxicants only in aerobic conditions, suggesting that BtuE is involved in the defense against oxidative damage. Genetic complementation of E. coli ΔbtuE restored toxicant resistance to levels exhibited by the wild type strain. As expected, btuE overexpression resulted in decreased amounts of oxidative damage products as well as in lower transcriptional levels of the oxidative stress-induced genes ibpA, soxS and katG.
Engineering Escherichia coli for methanol conversion.

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Müller, Jonas E N; Meyer, Fabian; Litsanov, Boris; Kiefer, Patrick; Potthoff, Eva; Heux, Stéphanie; Quax, Wim J; Wendisch, Volker F; Brautaset, Trygve; Portais, Jean-Charles; Vorholt, Julia A

2015-03-01

Methylotrophic bacteria utilize methanol and other reduced one-carbon compounds as their sole source of carbon and energy. For this purpose, these bacteria evolved a number of specialized enzymes and pathways. Here, we used a synthetic biology approach to select and introduce a set of "methylotrophy genes" into Escherichia coli based on in silico considerations and flux balance analysis to enable methanol dissimilation and assimilation. We determined that the most promising approach allowing the utilization of methanol was the implementation of NAD-dependent methanol dehydrogenase and the establishment of the ribulose monophosphate cycle by expressing the genes for hexulose-6-phosphate synthase (Hps) and 6-phospho-3-hexuloisomerase (Phi). To test for the best-performing enzymes in the heterologous host, a number of enzyme candidates from different donor organisms were selected and systematically analyzed for their in vitro and in vivo activities in E. coli. Among these, Mdh2, Hps and Phi originating from Bacillus methanolicus were found to be the most effective. Labeling experiments using (13)C methanol with E. coli producing these enzymes showed up to 40% incorporation of methanol into central metabolites. The presence of the endogenous glutathione-dependent formaldehyde oxidation pathway of E. coli did not adversely affect the methanol conversion rate. Taken together, the results of this study represent a major advancement towards establishing synthetic methylotrophs by gene transfer. Copyright © 2015 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.
Genome Sequences of Two Copper-Resistant Escherichia coli Strains Isolated from Copper-Fed Pigs

DEFF Research Database (Denmark)

Lüthje, Freja L.; Hasman, Henrik; Aarestrup, Frank Møller

2014-01-01

The draft genome sequences of two copper-resistant Escherichia coli strains were determined. These had been isolated from copper-fed pigs and contained additional putative operons conferring copper and other metal and metalloid resistances.......The draft genome sequences of two copper-resistant Escherichia coli strains were determined. These had been isolated from copper-fed pigs and contained additional putative operons conferring copper and other metal and metalloid resistances....
Annual Surveillance Summary: Escherichia coli (E. coli) Infections in the Military Health System (MHS), 2015

Science.gov (United States)

2017-03-01

Annual Surveillance Summary: Escherichia coli ( E . coli ) Infections in the Military Health System (MHS...or position of the Department of the Navy, Department of Defense, nor the U.S. Government. i i E . coli in the MHS: Annual Summary 2015 Prepared...March 2017 EpiData Center Department NMCPHC-EDC-TR-187-2017 ii ii E . coli in the MHS: Annual Summary 2015 Prepared March 2017 EpiData
The cell wall and cell division gene cluster in the Mra operon of Pseudomonas aeruginosa: cloning, production, and purification of active enzymes.

Science.gov (United States)

Azzolina, B A; Yuan, X; Anderson, M S; El-Sherbeini, M

2001-04-01

We have cloned the Pseudomonas aeruginosa cell wall biosynthesis and cell division gene cluster that corresponds to the mra operon in the 2-min region of the Escherichia coli chromosome. The organization of the two chromosomal regions in P. aeruginosa and E. coli is remarkably similar with the following gene order: pbp3/pbpB, murE, murF, mraY, murD, ftsW, murG, murC, ddlB, ftsQ, ftsA, ftsZ, and envA/LpxC. All of the above P. aeruginosa genes are transcribed from the same strand of DNA with very small, if any, intragenic regions, indicating that these genes may constitute a single operon. All five amino acid ligases, MurC, MurD, MurE, MurF, and DdlB, in addition to MurG and MraY were cloned in expression vectors. The four recombinant P. aeruginosa Mur ligases, MurC, MurD, MurE, and MurF were overproduced in E. coli and purified as active enzymes. Copyright 2001 Academic Press.
Enterohemorrhagic Escherichia coli (EHEC

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Abdullah Kilic

2011-08-01

Full Text Available Escherichia coli is a bacterium that is commonly found in the gut of humans and warm-blooded animals. Most strains of E. coli are harmless for human. E. coli O157:H7 is the most common member of a group of pathogenic E. coli strains known variously as enterohaemorrhagic, verocytotoxin-producing, or Shiga-toxin-producing organisms. EHEC bacterium is the major cause of haemorrhagic colitis and haemolytic uraemic syndrome. The reservoir of this pathogen appears to be mainly cattle and other ruminants such as camels. It is transmitted to humans primarily through consumption of contaminated foods. [TAF Prev Med Bull 2011; 10(4.000: 387-388
Impact of dry chilling on the genetic diversity of Escherichia coli on beef carcasses and on the survival of E. coli and E. coli O157.

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Visvalingam, Jeyachchandran; Liu, Yang; Yang, Xianqin

2017-03-06

The objective of this study was to examine the effect of dry chilling on the genetic diversity of naturally occurring Escherichia coli on beef carcasses, and to examine whether two populations of E. coli recovered from carcasses during chilling and E. coli O157 differed in their response to desiccation. Isolates of E. coli were obtained from beef carcasses during a 67h dry chilling process and were genotyped using multiple-locus variable-number tandem-repeat analysis (MLVA). Ten E. coli genotypes found only at 0h (group A) and found more than once (group B), as well as five strains of E. coli O157 (group C) were inoculated on stainless steel coupons and their survival was examined after exposure to 75 and 100% relative humidity (RH) at 0 or 35°C for 67h. A total of 450 E. coli isolates were obtained, with 254, 49, 49, 51, 23, 20, and 4 from 0, 1, 2, 4, 6, 8 and 24h of chilling, respectively. No E. coli were recovered at 67h. MLVA of the isolates revealed 173 distinct genotypes. Genetic diversity of E. coli isolates, defined as ratio of the number of isolates to the number of genotypes, remained between 2.3 and 1.3 during the 24h of chilling. All strains inoculated on stainless steel coupons and exposed to 75% RH at 35°C were completely inactivated, irrespective of their groups. Inactivation of E. coli of the three groups was not significantly (P>0.05) different by exposure to 75% RH at 0°C. The findings indicate that the genetic diversity of E. coli on beef carcasses was not affected by dry chilling. In addition, inactivation of E. coli genotypes and E. coli O157 by desiccation on stainless steel simulating dry chilling conditions did not differ significantly (P>0.05). Thus, dry chilling may be used as an effective antimicrobial intervention for beef carcasses. Crown Copyright © 2016. Published by Elsevier B.V. All rights reserved.
Development of a sensor for the detection of Escherichia coli in brackish waters

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Mancuso Monique

2016-03-01

Full Text Available Monitoring of bacterial pathogens is important for marine environmental protection, because the presence of these microorganisms can be a serious risk for human health. For this reason, a portable sensor implemented as an electronic embedded system featuring disposable measurement cells was used to evaluate the ability and sensitivity of detection of Escherichia coli (E. coli as an indicator of fecal pollution in transitional environments and a water sample added with E. coli (102 CFU/mL was assayed. The first result obtained from the laboratory experiment seems promising for the determination of E. coli in environmental samples, though further improvements will be needed for the field application of this sensor in marine and brackish waters.
Isolation and evaluation of cocktail phages for the control of multidrug-resistant Escherichia coli serotype O104: H4 and E. coli O157: H7 isolates causing diarrhea.

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Safwat Mohamed, Doaa; Farouk Ahmed, Eman; Mohamed Mahmoud, Abobakr; Abd El-Baky, Rehab Mahmoud; John, James

2018-02-01

Escherichia coli serotype O157: H7 and E. coli O104: H4 are well known foodborne pathogens causing sever enteric illness. Using bacteriophages as biocontrol agents of some foodborne pathogens and multidrug-resistant (MDR) bacteria has a great attention nowadays. This study aims to test the effect of cocktail phages on the growth of some foodborne pathogens and MDR E. coli. Routine conventional PCR was used to confirm the identification of E. coli isolates. Double-layered culture technique was used to isolate phages from sewage water. Morphology of bacteriophage was described using transmission electron microscopy, and spot test was performed to determine host range of the phage cocktail. Phage cocktail of Siphoviridae and Podoviridae family infecting E. coli O157: H7, E. coli O104: H4 and untypeable E. coli (neither O157 nor O104) has been isolated from sewage water. Phage cocktail showed both lytic and lysogenic activity. Lytic activity was observed against E. coli O157: H7, E. coli O104: H4 isolates, Staphylococcus. aureus ATCC6538 and Pseudomonas aeruginosa ATCC 10145, while the lysogenic activity was observed against the untypeable strain. The tested phage cocktail showed a promising inhibitory action on E. coli O157: H7 and O104: H4, S. aureus ATCC6538 and P. aeruginosa ATCC 10145, suggesting the possibility of its use as a biocontrol tool or as natural food preservatives for many food products. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
Drug Resistance Patterns of Escherichia coli in Ethiopia: A Meta-Analysis.

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Tuem, Kald Beshir; Gebre, Abadi Kahsu; Atey, Tesfay Mehari; Bitew, Helen; Yimer, Ebrahim M; Berhe, Derbew Fikadu

2018-01-01

Antimicrobial drug resistance is a global threat for treatment of infectious diseases and costs life and money and threatens health delivery system's effectiveness. The resistance of E. coli to frequently utilized antimicrobial drugs is becoming a major challenge in Ethiopia. However, there is no inclusive countrywide study. Therefore, this study intended to assess the prevalence of E. coli resistance and antimicrobial-specific resistance pattern among E. coli clinical isolates in Ethiopia. Articles were retrieved from PubMed, Embase, and grey literature from 2007 to 2017. The main outcome measures were overall E. coli and drug-specific resistance patterns. A random-effects model was used to determine pooled prevalence with 95% confidence interval (CI), using DerSimonian and Laird method. In addition, subgroup analysis was conducted to improve the outcome. The study bias was assessed by Begg's funnel plot. This study was registered in PROSPERO as follows: PROSPERO 2017: CRD42017070106. Of 164 articles retrieved, 35 articles were included. A total of 19,235 study samples participated in the studies and 2,635 E. coli strains were isolated. Overall, E. coli antibacterial resistance was 45.38% (95% confidence interval (CI): 33.50 to 57.27). The resistance pattern ranges from 62.55% in Addis Ababa to 27.51% in Tigray region. The highest resistance of E. coli reported was to ampicillin (83.81%) and amoxicillin (75.79%), whereas only 13.55% of E. coli isolates showed resistance to nitrofurantoin. E. coli antimicrobial resistance remains high with disparities observed among regions. The bacterium was found to be highly resistant to aminopenicillins. The finding implies the need for effective prevention strategies for the E. coli drug resistance and calls for multifaceted approaches with full involvement of all stakeholders.
Molecular characterization of Escherichia coli recovered from traditional milk products in Kashan, Iran

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Farhad Sharafati Chaleshtori

2017-10-01

Full Text Available Aim: Shiga toxigenic Escherichia coli (STEC strains as emerging groups of foodborne pathogens are responsible for most foodborne illnesses. The aim of this study was to determine the antibiotic resistance pattern in STEC isolated from traditional milk products and their molecular characterization. Materials and Methods: A total of 116 samples were randomly purchased from local markets in Kashan, Iran, and evaluated for the occurrence of STEC by culturing and molecular methods. The antibiotic resistance of obtained isolates was determined by Kirby Bauer method. Furthermore, isolates were assayed for the presence of Shiga toxins (stx1 and stx2 and intimin gene (eae. Results: The incidence of E. coli in 60 ice cream, 30 yoghurt, and 26 cheese samples was 8.33%, 10%, and 11.54%, respectively. The findings showed that 11 out of 11 (100% E. coli had both stx1 and stx2 while eae gene was not found in E. coli isolated of traditional milk products. For E. coli strains carrying stx1 and stx2, highest antibiotic sensitive levels were related to trimethoprim/sulfamethoxazole, norfloxacin, chloramphenicol, and ciprofloxacin, respectively. Conclusion: The results showed relationship between the presence of virulence factors and antimicrobial resistance. These results can be used for further studies on STEC as an emerging foodborne pathogen.
Comparative Genomics and Characterization of Hybrid Shigatoxigenic and Enterotoxigenic Escherichia coli (STEC/ETEC) Strains.

Science.gov (United States)

Nyholm, Outi; Halkilahti, Jani; Wiklund, Gudrun; Okeke, Uche; Paulin, Lars; Auvinen, Petri; Haukka, Kaisa; Siitonen, Anja

2015-01-01

Shigatoxigenic Escherichia coli (STEC) and enterotoxigenic E. coli (ETEC) cause serious foodborne infections in humans. These two pathogroups are defined based on the pathogroup-associated virulence genes: stx encoding Shiga toxin (Stx) for STEC and elt encoding heat-labile and/or est encoding heat-stable enterotoxin (ST) for ETEC. The study investigated the genomics of STEC/ETEC hybrid strains to determine their phylogenetic position among E. coli and to define the virulence genes they harbor. The whole genomes of three STEC/ETEC strains possessing both stx and est genes were sequenced using PacBio RS sequencer. Two of the strains were isolated from the patients, one with hemolytic uremic syndrome, and one with diarrhea. The third strain was of bovine origin. Core genome analysis of the shared chromosomal genes and comparison with E. coli and Shigella spp. reference genomes was performed to determine the phylogenetic position of the STEC/ETEC strains. In addition, a set of virulence genes and ETEC colonization factors were extracted from the genomes. The production of Stx and ST were studied. The human STEC/ETEC strains clustered with strains representing ETEC, STEC, enteroaggregative E. coli, and commensal and laboratory-adapted E. coli. However, the bovine STEC/ETEC strain formed a remote cluster with two STECs of bovine origin. All three STEC/ETEC strains harbored several other virulence genes, apart from stx and est, and lacked ETEC colonization factors. Two STEC/ETEC strains produced both toxins and one strain Stx only. This study shows that pathogroup-associated virulence genes of different E. coli can co-exist in strains originating from different phylogenetic lineages. The possibility of virulence genes to be associated with several E. coli pathogroups should be taken into account in strain typing and in epidemiological surveillance. Development of novel hybrid E. coli strains may cause a new public health risk, which challenges the traditional diagnostics

Comparative Genomics and Characterization of Hybrid Shigatoxigenic and Enterotoxigenic Escherichia coli (STEC/ETEC Strains.

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Outi Nyholm

Full Text Available Shigatoxigenic Escherichia coli (STEC and enterotoxigenic E. coli (ETEC cause serious foodborne infections in humans. These two pathogroups are defined based on the pathogroup-associated virulence genes: stx encoding Shiga toxin (Stx for STEC and elt encoding heat-labile and/or est encoding heat-stable enterotoxin (ST for ETEC. The study investigated the genomics of STEC/ETEC hybrid strains to determine their phylogenetic position among E. coli and to define the virulence genes they harbor.The whole genomes of three STEC/ETEC strains possessing both stx and est genes were sequenced using PacBio RS sequencer. Two of the strains were isolated from the patients, one with hemolytic uremic syndrome, and one with diarrhea. The third strain was of bovine origin. Core genome analysis of the shared chromosomal genes and comparison with E. coli and Shigella spp. reference genomes was performed to determine the phylogenetic position of the STEC/ETEC strains. In addition, a set of virulence genes and ETEC colonization factors were extracted from the genomes. The production of Stx and ST were studied.The human STEC/ETEC strains clustered with strains representing ETEC, STEC, enteroaggregative E. coli, and commensal and laboratory-adapted E. coli. However, the bovine STEC/ETEC strain formed a remote cluster with two STECs of bovine origin. All three STEC/ETEC strains harbored several other virulence genes, apart from stx and est, and lacked ETEC colonization factors. Two STEC/ETEC strains produced both toxins and one strain Stx only.This study shows that pathogroup-associated virulence genes of different E. coli can co-exist in strains originating from different phylogenetic lineages. The possibility of virulence genes to be associated with several E. coli pathogroups should be taken into account in strain typing and in epidemiological surveillance. Development of novel hybrid E. coli strains may cause a new public health risk, which challenges the
Pharmacokinetic-Pharmacodynamic Modeling of Enrofloxacin Against Escherichia coli in Broilers.

Science.gov (United States)

Sang, KaNa; Hao, HaiHong; Huang, LingLi; Wang, Xu; Yuan, ZongHui

2015-01-01

The purpose of the present study was to establish a pharmacokinetic/pharmacodynamic (PK/PD) modeling approach for the dosage schedule design and decreasing the emergence of drug-resistant bacteria. The minimal inhibitory concentration (MIC) of 929 Escherichia coli isolates from broilers to enrofloxacin and ciprofloxacin was determined following CLSI guidance. The MIC50 was calculated as the populational PD parameter for enrofloxacin against E. coli in broilers. The 101 E. coli strains with MIC closest to the MIC50 (0.05 μg/mL) were submitted for serotype identification. The 13 E. coli strains with O and K serotype were further utilized for determining pathogencity in mice. Of all the strains tested, the E. coli designated strain Anhui 112 was selected for establishing the disease model and PK/PD study. The PKs of enrofloxacin after oral administration at the dose of 10 mg/kg body weights (BW) in healthy and infected broilers was evaluated with high-performance liquid chromatography (HPLC) method. For intestinal contents after oral administration, the peak concentration (C max), the time when the maximum concentration reached (T max), and the area under the concentration-time curve (AUC) were 21.69-31.69 μg/mL, 1.13-1.23 h, and 228.97-444.86 μg h/mL, respectively. The MIC and minimal bactericidal concentration (MBC) of enrofloxacin against E. coli (Anhui 112) in Mueller-Hinton (MH) broth and intestinal contents were determined to be similar, 0.25 and 0.5 μg/mL respectively. In this study, the sum of concentrations of enrofloxacin and its metabolite (ciprofloxacin) was used for the PK/PD integration and modeling. The ex vivo growth inhibition data were fitted to the sigmoid E max (Hill) equation to provide values for intestinal contents of 24 h area under concentration-time curve/MIC ratios (AUC0-24 h/MIC) producing, bacteriostasis (624.94 h), bactericidal activity (1065.93 h) and bacterial eradication (1343.81 h). PK/PD modeling was
Pharmacokinetic-Pharmacodynamic modeling of enrofloxacin against Escherichia coli in broilers

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Sang eKana

2016-01-01

Full Text Available The purpose of the present study was to establish a pharmacokinetic/pharmacodynamic (PK/PD modeling approach for the dosage schedule design and decreasing the emergence of drug-resistant bacteria. The minimal inhibitory concentration (MIC of 929 E. coli isolates from broilers to enrofloxacin and ciprofloxacin were determined following CLSI guidance. The MIC50 was calculated as the populational PD parameter for enrofloxacin against E. coli in broilers. The 101 E. coli strains with MIC closest to the MIC50 (0.05µg/mL were submitted for serotype identification. The 13 E. coli strains with O and K serotype were further utilitzed for determining pathogencity in mice. Of all the strains tested, the E. coli designated strain Anhui 112 was selected for establishing the disease model and PK/PD study. The pharmacokinetics (PKs of enrofloxacin after oral administration at the dose of 10mg/kg body weights (BW in healthy and infected broilers was evaluated with high-performance liquid chromatography (HPLC method. For intestinal contents after oral administration, the peak concentration (Cmax, the time when the maximum concentration reached (Tmax, and the area under the concentration-time curve (AUC were 21.69~31.69μg/mL, 1.13~1.23h, and 228.97~444.86μg.hr/mL, respectively. The MIC and minimal bactericidal concentration (MBC of enrofloxacin against E. coli (Anhui 112 in Mueller-Hinton (MH broth and intestinal contents were determined to be similar, 0.25μg/mL and 0.5μg/mL respectively. In this study, the sum of concentrations of enrofloxacin and its metabolite (ciprofloxacin was used for the PK/PD integration and modeling. The ex vivo growth inhibition data were fitted to the sigmoid Emax (Hill equation to provide values for intestinal contents of 24h area under concentration–time curve/MIC ratios (AUC0~24h/MIC producing, bacteriostasis (624.94h, bactericidal activity (1065.93h and bacterial eradication (1343.81h. PK/PD modeling was established to
Epidemiology and Characteristics of Escherichia coli Sequence Type 131 (ST131) from Long-Term Care Facility Residents Colonized Intestinally with Fluoroquinolone-Resistant Escherichia coli

Science.gov (United States)

Han, Jennifer H.; Garrigan, Charles; Johnston, Brian; Nachamkin, Irving; Clabots, Connie; Bilker, Warren B.; Santana, Evelyn; Tolomeo, Pam; Maslow, Joel; Myers, Janice; Carson, Lesley; Lautenbach, Ebbing; Johnson, James R.

2016-01-01

The objective of this study was to evaluate molecular and epidemiologic factors associated with Escherichia coli sequence type 131 (ST131) among long-term care facility (LTCF) residents who acquired gastrointestinal tract colonization with fluoroquinolone-resistant E. coli (FQREC). Colonizing isolates from 37 residents who newly developed FQREC colonization at three LTCFs from 2006–2008 were evaluated. Twenty-nine (78%) of 37 total FQREC colonizing isolates were ST131. Most ST131 isolates had a distinctive combination of gyrA and parC replacement mutations. The ST131 and non-ST131 isolates differed significantly for the prevalence of many individual virulence factors but not for the proportion that qualified molecularly as extraintestinal pathogenic E. coli (ExPEC) or aggregate virulence factor scores. E. coli ST131 was highly prevalent among LTCF residents with FQREC colonization. Future studies should determine the risk factors for infection among ST131-colonized residents, and assess the potential for increased transmissibility of ST131 in the long-term care setting. PMID:27939288
Are Escherichia coli Pathotypes Still Relevant in the Era of Whole-Genome Sequencing?

Science.gov (United States)

Robins-Browne, Roy M.; Holt, Kathryn E.; Ingle, Danielle J.; Hocking, Dianna M.; Yang, Ji; Tauschek, Marija

2016-01-01

The empirical and pragmatic nature of diagnostic microbiology has given rise to several different schemes to subtype E.coli, including biotyping, serotyping, and pathotyping. These schemes have proved invaluable in identifying and tracking outbreaks, and for prognostication in individual cases of infection, but they are imprecise and potentially misleading due to the malleability and continuous evolution of E. coli. Whole genome sequencing can be used to accurately determine E. coli subtypes that are based on allelic variation or differences in gene content, such as serotyping and pathotyping. Whole genome sequencing also provides information about single nucleotide polymorphisms in the core genome of E. coli, which form the basis of sequence typing, and is more reliable than other systems for tracking the evolution and spread of individual strains. A typing scheme for E. coli based on genome sequences that includes elements of both the core and accessory genomes, should reduce typing anomalies and promote understanding of how different varieties of E. coli spread and cause disease. Such a scheme could also define pathotypes more precisely than current methods. PMID:27917373
Can E. coli fly?

DEFF Research Database (Denmark)

Lindeberg, Yrja Lisa; Egedal, Karen; Hossain, Zenat Zebin

2018-01-01

, and the numbers of flies landing on the exposed rice were counted. Following exposure, the surface of the rice was microbiologically and molecularly analysed for the presence of E. coli and genes of diarrheagenic E. coli and Shigella strains. RESULTS: Rice was at greater risk (p ... with E. coli if flies landed on the rice than if no flies landed on the rice (odds ratio 5·4 (p ...-landings, the average CFU per fly-landing was > 0·6 x 103 CFU. Genes of diarrheagenic E. coli and Shigella species were detected in 39 of 60 (65%) of exposed rice samples. Two fly species were identified; the common housefly (Musca domestica) and the oriental latrine fly (Chrysomya megacephala). CONCLUSION: Flies may...
Identification, characterization and molecular epidemiology of Escherichia coli isolated from lamb and goat kids with diarrhoea

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Süheyla Türkyılmaz

2013-01-01

Full Text Available Neonatal diarrhoea is a serious health problem on commercial farms. Enterovirulent Escherichia coli is a significant aetiological agent of neonatal diarrhoea. In this work, identification and classification of E. coli isolates obtained from lambs and goat kids with diarrhoea were studied along with antibiotic resistance and clonal relationships of enterovirulent strains. A total of 107 E. coli strains isolated from animals on 43 farms were investigated. Specific virulence genes were determined by multiplex and uniplex polymerase chain reaction. Testing of antibiotic susceptibility was carried out by the Vitek II compact system. The relationship of E. coli isolates was determined by enterobacterial repetitive intergenic consensus polymerase chain reaction. A total of 39 (36.4% enterovirulent E. coli strains were identified and of this 19 (48.7% were shiga toxigenic, 12 (30.8% enterotoxigenic and 8 (20.5% enteropathogenic. Three isolates (7.7% were found to be positive for extended spectrum beta lactamase; 10 (25.6% isolates showed multi-drug resistance to antimicrobials. A total of 28 types were detected by enterobacterial repetitive intergenic consensus polymerase chain reaction. Twenty strains had distinct types while 5 types were common for 2 strains and 3 types were common for 3 strains. This is the first current determination of types, clonality and antibiotic resistance of enterovirulent E. coli isolated from small ruminants with diarrhoea. The results of this study showed that the rates of shiga toxigenic, enterotoxigenic and enteropathogenic isolates of E. coli are high in the western part of Turkey. Although these isolates were not clonal, presence of multidrug resistant isolates may cause public health problems.
Determination of gamma radiation dose to the destruction of Escherichia coli O157: H7 in hamburger

International Nuclear Information System (INIS)

Orejuela Chirinos, Rodolfo Raul

1999-01-01

Escherichia coli O157:H7 has been incriminated in several foodborne outbreaks due to the consumption of different kinds of foods. Among these, hamburgers are the most common. Irradiation process is an effective method for food preservation because it causes no significant change in organoleptic and nutritional food characteristics and destroys pathogens and spoilage microorganisms. Hamburgers and nutrient broth inoculated with Escherichia coli O157:H7 were submitted to gamma irradiation ( 60 Co) treatment, with doses ranging from 0,0 to 0,7 kGy in order to calculate the D 10 for this bacteria in these substrate. The D 10 for the pathogen nutrient broth ranged from 0.08 kGy to 0.10 kGy and in hamburger from 0.11 kGy to 0.21 kGy. Considering the highest D 10 value in hamburger, a dose of 0,8 kGy would not change the sensorial characteristics of the product, and would reduce the population of E. coli O157:H7 in 4 cycles logarithmic. (author)
Detection and linkage to mobile genetic elements of tetracycline resistance gene tet(M) in Escherichia coli isolates from pigs

DEFF Research Database (Denmark)

Jurado-Rabadan, Sonia; de la Fuente, Ricardo; Ruiz-Santa-Quiteria, Jose A.

2014-01-01

Background: In Escherichia coli the genes involved in the acquisition of tetracycline resistance are mainly tet(A) and tet(B). In addition, tet(M) is the most common tetracycline resistance determinant in enterococci and it is associated with conjugative transposons and plasmids. Although tet......(M) has been identified in E. coli, to our knowledge, there are no previous reports studying the linkage of the tet(M) gene in E. coli to different mobile genetic elements. The aim of this study was to determine the occurrence of tet(A), tet(B), and tet(M) genes in doxycycline-resistant E. coli isolates...... from pigs, as well as the detection of mobile genetic elements linked to tet(M) in E. coli and its possible transfer from enterococci. Results: tet(A) was the most frequently detected gene (87.9%) in doxycycline-resistant isolates. tet(M) was found in 13.1% E. coli isolates. The tet(M) gene...
Antimicrobial resistance in faecal Escherichia coli isolates from farmed red deer and wild small mammals. Detection of a multiresistant E. coli producing extended-spectrum beta-lactamase.

Science.gov (United States)

Alonso, C A; González-Barrio, D; Tenorio, Carmen; Ruiz-Fons, F; Torres, C

2016-04-01

Eighty-nine Escherichia coli isolates recovered from faeces of red deer and small mammals, cohabiting the same area, were analyzed to determine the prevalence and mechanisms of antimicrobial resistance and molecular typing. Antimicrobial resistance was detected in 6.7% of isolates, with resistances to tetracycline and quinolones being the most common. An E. coli strain carrying blaCTX-M-1 as well as other antibiotic resistant genes included in an unusual class 1 integron (Intl1-dfrA16-blaPSE-1-aadA2-cmlA1-aadA1-qacH-IS440-sul3-orf1-mef(B)Δ-IS26) was isolated from a deer. The blaCTX-M-1 gene was transferred by conjugation and transconjugants also acquired an IncN plasmid. This strain was typed as ST224, which seems to be well adapted to both clinical and environmental settings. The phylogenetic distribution of the 89 strains varied depending on the animal host. This work reveals low antimicrobial resistance levels among faecal E. coli from wild mammals, which reflects a lower selective pressure affecting these bacteria, compared to livestock. However, it is remarkable the detection of a multi-resistant ESBL-E. coli with an integron carrying clinically relevant antibiotic-resistance genes, which can contribute to the dissemination of resistance determinants among different ecosystems. Copyright © 2016 Elsevier Ltd. All rights reserved.
Strain-Level Discrimination of Shiga Toxin-Producing Escherichia coli in Spinach Using Metagenomic Sequencing.

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Susan R Leonard

Full Text Available Consumption of fresh bagged spinach contaminated with Shiga toxin-producing Escherichia coli (STEC has led to severe illness and death; however current culture-based methods to detect foodborne STEC are time consuming. Since not all STEC strains are considered pathogenic to humans, it is crucial to incorporate virulence characterization of STEC in the detection method. In this study, we assess the comprehensiveness of utilizing a shotgun metagenomics approach for detection and strain-level identification by spiking spinach with a variety of genomically disparate STEC strains at a low contamination level of 0.1 CFU/g. Molecular serotyping, virulence gene characterization, microbial community analysis, and E. coli core gene single nucleotide polymorphism (SNP analysis were performed on metagenomic sequence data from enriched samples. It was determined from bacterial community analysis that E. coli, which was classified at the phylogroup level, was a major component of the population in most samples. However, in over half the samples, molecular serotyping revealed the presence of indigenous E. coli which also contributed to the percent abundance of E. coli. Despite the presence of additional E. coli strains, the serotype and virulence genes of the spiked STEC, including correct Shiga toxin subtype, were detected in 94% of the samples with a total number of reads per sample averaging 2.4 million. Variation in STEC abundance and/or detection was observed in replicate spiked samples, indicating an effect from the indigenous microbiota during enrichment. SNP analysis of the metagenomic data correctly placed the spiked STEC in a phylogeny of related strains in cases where the indigenous E. coli did not predominate in the enriched sample. Also, for these samples, our analysis demonstrates that strain-level phylogenetic resolution is possible using shotgun metagenomic data for determining the genomic relatedness of a contaminating STEC strain to other
Identification of genes important for growth of asymptomatic bacteriuria Escherichia coli in urine.

Science.gov (United States)

Vejborg, Rebecca M; de Evgrafov, Mari R; Phan, Minh Duy; Totsika, Makrina; Schembri, Mark A; Hancock, Viktoria

2012-09-01

Escherichia coli is the most important etiological agent of urinary tract infections (UTIs). Unlike uropathogenic E. coli, which causes symptomatic infections, asymptomatic bacteriuria (ABU) E. coli strains typically lack essential virulence factors and colonize the bladder in the absence of symptoms. While ABU E. coli can persist in the bladder for long periods of time, little is known about the genetic determinants required for its growth and fitness in urine. To identify such genes, we have employed a transposon mutagenesis approach using the prototypic ABU E. coli strain 83972 and the clinical ABU E. coli strain VR89. Six genes involved in the biosynthesis of various amino acids and nucleobases were identified (carB, argE, argC, purA, metE, and ilvC), and site-specific mutants were subsequently constructed in E. coli 83972 and E. coli VR89 for each of these genes. In all cases, these mutants exhibited reduced growth rates and final cell densities in human urine. The growth defects could be complemented in trans as well as by supplementation with the appropriate amino acid or nucleobase. When assessed in vivo in a mouse model, E. coli 83972carAB and 83972argC showed a significantly reduced competitive advantage in the bladder and/or kidney during coinoculation experiments with the parent strain, whereas 83972metE and 83972ilvC did not. Taken together, our data have identified several biosynthesis pathways as new important fitness factors associated with the growth of ABU E. coli in human urine.
99mTechnetium labelled Escherichia coli

International Nuclear Information System (INIS)

Diniz, S.O.F.; Cardoso, V.N.; Resende, B.M.; Nunan, E.A.; Simal, C.J.R.

1999-01-01

Samples of a culture of unlabeled Escherichia coli were incubated with different concentrations of stannous chloride for various time periods. 99m Tc (26.0 MBq) was added to each preparation and the results showed a labelling yield of 98% for E. coli. Since the bacterial viability of 99m Tc-E. coli and E. coli did not show any statistical differences, these results demonstrate that labelling of E. coli with 99m Tc does not modify the bacterial viability, and the radiolabelled bacteria may be a good model to study bacterial translocation
High carriage of adherent invasive E. coli in wildlife and healthy individuals.

Science.gov (United States)

Rahmouni, Oumaïra; Vignal, Cécile; Titécat, Marie; Foligné, Benoît; Pariente, Benjamin; Dubuquoy, Laurent; Desreumaux, Pierre; Neut, Christel

2018-01-01

Adherent invasive Escherichia coli (AIEC) are suspected to be involved in the pathogenesis of inflammatory bowel diseases. Since AIEC was first described in 1999, despite important progress on its genomic and immune characterizations, some crucial questions remain unanswered, such as whether there exists a natural reservoir, or whether there is asymptomatic carriage. The ECOR collection, including E. coli strains isolated mainly from the gut of healthy humans and animals, constitutes an ideal tool to investigate AIEC prevalence in healthy condition. A total of 61 E. coli strains were examined for characteristics of AIEC. The adhesion, invasion and intramacrophage replication capabilities (AIEC phenotype) of 61 intestinal E. coli strains were determined. The absence of virulence-associated diarrheagenic E. coli pathotypes (EPEC, ETEC, EIEC, EHEC, DAEC, EAEC), and uropathogenic E. coli was checked. Out of 61 intestinal strains, 13 (21%) exhibit the AIEC phenotype, 7 are from human origin and 6 are from animal origin. Prevalence of AIEC strains is about 24 and 19% in healthy humans and animals respectively. These strains are highly genetically diverse as they are distributed among the main described phylogroups. Among E. coli strains from the ECOR collection, we also detected strains able to detach I-407 cells. Our study described for the first time AIEC strains isolated from the feces of healthy humans and animals.
Prevalence of Balantidium coli Infection in Bred Rhesus Monkeys (Macaca mulatta in Guangxi, southern China.

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Hai Long Li

2014-03-01

Full Text Available Balantidium coli infects humans, primates and pigs, causing serious diarrhea and dysentery. Little information on the prevalence of B. coli in primates is available in China. This investigation was conducted to determine the prevalence of B. coli infection in bred rhesus monkeys in Guangxi Zhuang Nationality Autonomous Region (GZNAR, southern China.A total of 120 fecal samples were collected from rhesus monkeys bred in cages in GZNAR and B. coli cysts and/or trophozoites were examined microscopically after sedimentation with water in May 2013.(64.2% samples were tested positive. The prevalence was 65% (39/60 and 63.3% (38/60 in female and male monkeys, respectively. 80% (48/60 cages in this nonhuman primate center were positive for B. coli.The present survey revealed high circulation of B. coli in bred rhesus monkeys in GZNAR, which poses potential threats to animal and human health.
The population structure of Escherichia coli isolated from subtropical and temperate soils

Science.gov (United States)

Byappanahalli, Muruleedhara N.; Yan, Tao; Hamilton, Matthew J.; Ishii, Satoshi; Fujioka, Roger S.; Whitman, Richard L.; Sadowsky, Michael J.

2012-01-01

While genotypically-distinct naturalized Escherichia coli strains have been shown to occur in riparian soils of Lake Michigan and Lake Superior watersheds, comparative analyses of E. coli populations in diverse soils across a range of geographic and climatic conditions have not been investigated. The main objectives of this study were to: (a) examine the population structure and genetic relatedness of E. coli isolates collected from different soil types on a tropical island (Hawaii), and (b) determine if E. coli populations from Hawaii and temperate soils (Indiana, Minnesota) shared similar genotypes that may be reflective of biome-related soil conditions. DNA fingerprint and multivariate statistical analyses were used to examine the population structure and genotypic characteristics of the E. coli isolates. About 33% (98 of 293) of the E. coli from different soil types and locations on the island of Oahu, Hawaii, had unique DNA fingerprints, indicating that these bacteria were relatively diverse; the Shannon diversity index for the population was 4.03. Nearly 60% (171 of 293) of the E. coli isolates from Hawaii clustered into two major groups and the rest, with two or more isolates, fell into one of 22 smaller groups, or individual lineages. Multivariate analysis of variance of 89, 21, and 106 unique E. coli DNA fingerprints for Hawaii, Indiana, and Minnesota soils, respectively, showed that isolates formed tight cohesive groups, clustering mainly by location. However, there were several instances of clonal isolates being shared between geographically different locations. Thus, while nearly identical E. coli strains were shared between disparate climatologically- and geographically-distinct locations, a vast majority of the soil E. coli strains were genotypically diverse and were likely derived from separate lineages. This supports the hypothesis that these bacteria are not unique and multiple genotypes can readily adapt to become part of the soil autochthonous
The oxygen effect in E. coli cells

International Nuclear Information System (INIS)

Myasnik, M.N.; Skvortsov, V.G.; Sokolov, V.A.

1982-01-01

In experiments on E. coli strains deficient in some stages of DNA repair from radiation damages, it was demonstrated that the value of the oxygen effect, under optimal conditions for manifestation thereof, decreases in the following order: E. coli WP2 (the wild type) → E. coli WP2 exr - and E. coli B → E. coli WP2 uvr A6 → E. coli WP2 rec Al and E. coli WP2 hcr - exr - . It was detected that 0.14 M NaCl solution sensitizes the anoxic cells of some E. coli strains to the effect of γ-radiation. It was established that mutation of the uvr A-gene increases sharply the sensitivity of cells to iradiation under the anoxic conditions in the presence of NaCl, the reverse'' oxygen effect being observed
Detection of multi-drug resistant Escherichia coli in the urban waterways of Milwaukee, WI

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Anthony D. Kappell

2015-04-01

Full Text Available Urban waterways represent a natural reservoir of antibiotic resistance which may provide a source of transferable genetic elements to human commensal bacteria and pathogens. The objective of this study was to evaluate antibiotic resistance of Escherichia coli isolated from the urban waterways of Milwaukee, WI compared to those from Milwaukee sewage and a clinical setting in Milwaukee. Antibiotics covering 10 different families were utilized to determine the phenotypic antibiotic resistance for all 259 E. coli isolates. All obtained isolates were determined to be multi-drug resistant. The E. coli isolates were also screened for the presence of the genetic determinants of resistance including ermB (macrolide resistance, tet(M (tetracycline resistance, and β-lactamases (blaOXA, blaSHV, and blaPSE. E. coli from urban waterways showed a greater incidence of antibiotic resistance to 8 of 17 antibiotics tested compared to human derived sources. These E. coli isolates also demonstrated a greater incidence of resistance to higher numbers of antibiotics compared to the human derived isolates. The urban waterways demonstrated a greater abundance of isolates with co-occurrence of antibiotic resistance than human derived sources. When screened for 5 different antibiotic resistance genes conferring macrolide, tetracycline, and β-lactam resistance, clinical E. coli isolates were more likely to harbor ermB and blaOXA than isolates from urban waterway. These results indicate that Milwaukee’s urban waterways may select for a greater incidence of multiple antibiotic resistance organisms and likely harbor a different antibiotic resistance gene pool than clinical sources. The implications of this study are significant to understanding the presence of resistance in urban freshwater environments by supporting the idea that sediment from urban waterways serves as a reservoir of antibiotic resistance.
Hemolytic porcine intestinal Escherichia coli without virulence-associated genes typical of intestinal pathogenic E. coli.

Science.gov (United States)

Schierack, Peter; Weinreich, Joerg; Ewers, Christa; Tachu, Babila; Nicholson, Bryon; Barth, Stefanie

2011-12-01

Testing 1,666 fecal or intestinal samples from healthy and diarrheic pigs, we obtained hemolytic Escherichia coli isolates from 593 samples. Focusing on hemolytic E. coli isolates without virulence-associated genes (VAGs) typical for enteropathogens, we found that such isolates carried a broad variety of VAGs typical for extraintestinal pathogenic E. coli.
escherichia coli serotypes confirmed in experimental mammary ...

African Journals Online (AJOL)

DJFLEX

VARIATIONS IN VIRULENCE OF THREE (3) ESCHERICHIA COLI. SEROTYPES CONFIRMED IN ... ows are susceptible to E. coli infection because. E. coli exist in the .... Coli infections in mice: A laboratory animal model for research in.

Study of Antibacterial Effect of Novel Thiazole, Imidazole and Tetrahydropyridine Derivatives against Escherichia coli

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Behzad Ghasemi

2016-01-01

Full Text Available > Introduction: Escherichia coli is one of the important pathogens in human with globalimportance. Because of the necessity for identification and the use of novel antibacterialcompounds against E. coli, in this present study we focused on the antibacterial effects ofsynthesized thiazole, imidazole and tetrahydropyridine derivatives on E. coli.Methods: For evaluation of antibacterial effect, the disk diffusion method was applied to measurethe growth inhibition zone diameter and broth micro-dilution was performed to determine theminimum inhibitory concentration (MIC.Results: Assessing the antibacterial effect showed that only 6d derivative of thiazole hadinhibitory effect on E. coli and the other thiazole, imidazole and tetrahydropyridine derivativeslacked any inhibitory result on this organism. The inhibitory effect of 6d derivative of thiazolewas MIC=125 and growth inhibition zone diameter of 16±0.1.Discussion: The antibacterial effect of thiazole, imidazole and tetrahydropyridine derivativesdiffers from each other and chemical linkages such as oxygen to thiazole ring in 6d derivative,could have reinforced this effect. The next step is determination of the toxicity and therapeuticeffects in the laboratory animals.
Inactivation of the Escherichia coli chromosome during growth after ultraviolet irradiation

Energy Technology Data Exchange (ETDEWEB)

Medic-Petranovic, M; Trgovcevic, Z; Novak, D; Petranovic, D [Institut Rudjer Boskovic, Zagreb (Yugoslavia)

1977-07-01

Cells of the repair-proficient E.coli AB1157 strain and its lysogenic E.coli AB1157 (lambda c1857 ind) counterpart have been uv irradiated in an attempt to define when and why cells that are destined to die reach their biological end-point in the course of post-irradiation incubation. The thermo-inducibility of the lambdac1857 ind lysogens was first determined, since this reflects the functional integrity of the pro-viral part of the bacterial chromosome and that of the bacterial cytoplasm. The capacity (i.e. the ability of the irradiated cells to support growth of the unirradiated phage) was then determined, since this depends on the functional integrity of the bacterial cytoplasm. A progressive decrease in the ability of the lysogens to be heat-induced always preceded the decrease in capacity for the phage growth. The results strongly suggest that wild-type E.coli cells destined to die after exposure to moderate doses of uv-light reach their end point within 4 hours of post-irradiation incubation, probably as a result of the functional failure of the whole chromosome.
[Effect of Pseudomonas aeruginosa exometabolites on planktonic and biofilm cultures of Escherichia coli].

Science.gov (United States)

Kuznetsova, M V; Karpunina, T I; Maslennikova, I L; Nesterova, L Iu; Demakov, V A

2012-01-01

Study the effect of P. aeruginosa exometabolites on planktonic and biofilm cultures of bioluminescent E. coli strain. E. coli K12 TG1 (pF1 lux+ Ap(r)) recombinant bioluminescent strain, P. aeruginosa ATCC 27853 reference strain and 2 nosocomial isolates were used. Pyocyanin and pyoverdin content in supernatant of P. aeruginosa over-night cultures was evaluated according to E. Deziel et al. (2001). Planktonic and biofilm cultures of E. coli were obtained in 96-well plates (LB, statically, 37 degrees C), optical density of plankton, film biomass (OD600, OD580) and bioluminescence in plankton and biofilm were evaluated in microplate reader Infiniti M200 (Tecan, Austria). P. aeruginosa exometabolites increased the duration of lag-phase in E. coli, and short term exposition inhibited luminescence of planktonic cells. These effects are determined by bactericidal action ofpyocyanin and pyoverdin. Supernatants ofover-night cultures of P. aeruginosa inhibit formation of biofilm and disrupt the formed biofilm of E. coli. Effect of pyocyanin and pyoverdin on these processes is not established, other factors may have higher significance. Bioluminescence of E. coli K12 TGI that reflects the energetic status of the cell allows to evaluate and prognose the character of coexistence of P. aeruginosa in combined with E. coli planktonic and biofilm culture.
Antibiogram of escherichia coli isolated from urine samples at a tertiary care hospital

International Nuclear Information System (INIS)

Chaudary, Z.A.; Hasan, A.; Alizai, S.A.

2015-01-01

To determine prevalence and antibiotic susceptibility pattern of the E. coli isolated from urine in our setup, especially in low income group of population. Methodology: The study was carried out from July 2010 to June 2011 at surgical and urological units of a hospital in Islamabad. E.coli were isolated from urine specimens by following standard microbiological techniques. Antimicrobial susceptibility test was performed by using the Kirby-Bauer disc diffusion techniques according to CLSI guidelines. Results: The prevalence of E. coli isolated from urine samples was 28.22%. Highest resistance was seen against ampicillin (80.3%). Imipenem was found out to be highly effective. Conclusion: Imipenem, ciprofloxacin and sparfloxacin can be reliably used against E. coli causing urinary tract infections. Gentamicin and moxifloxacin also showed satisfactory results. (author)
Identification and Prevalence of Escherichia coli and Escherichia coli O157: H7 in Foods

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Ancuta Mihaela Rotar

2013-11-01

Full Text Available The objective of this study is to investigate the incidence of Escherichia coli in animal and non-animal foods, and mainly the incidence of the serotype O157: H7 producing verotoxin. The presence of common Escherichia coli and Escherichia coli O157: H7 in various foods (of animal and non animal origin was performed in Transylvania area. We analyzed a total of one hundred forty-one samples of minced meat, one hundred twenty-six samples of meat , twenty six samples of meat products, five samples of alcoholic beverages, three samples of seafood, one hundred samples of cheese from pasteurized milk, seventeen samples of butter, four samples of vegetables and one sample of milk powder, using the standard cultural method and Vidas Eco method for E. coli O157: H7 strains. E. coli was identified in 50 samples of minced meat, 55 samples of meat prepared, 4 samples of meat products, 2 samples of alcoholic beverages, 25 samples of cheese from pasteurized milk, 6 samples of butter and 1 sample of vegetables. In this study were not been identified any foods contaminated with the E. coli O157: H7 serotype. The results of this reasearch have demostrated that E. coli wich represents a hygienic indicator of recent food contamination, can be destroyed with heat treatment and hygienic handling of foods. Our country over the years has been among the few countries where the incidence of the E. coli O157: H7 serotype has been minimal.
The asymptomatic bacteriuria Escherichia coli strain 83972 outcompetes uropathogenic E. coli strains in human urine

DEFF Research Database (Denmark)

Hancock, Viktoria; Ulett, G.C.; Schembri, M.A.

2006-01-01

Escherichia coli is the most common organism associated with asymptomatic bacteriuria (ABU). In contrast to uropathogenic E. coli (UPEC), which causes symptomatic urinary tract infections (UTI), very little is known about the mechanisms by which these strains colonize the human urinary tract....... The prototype ABU E. coli strain 83972 was originally isolated from a girl who had carried it asymptomatically for 3 years. Deliberate colonization of UTI-susceptible individuals with E. coli 83972 has been used successfully as an alternative approach for the treatment of patients who are refractory...... to conventional therapy. Colonization with strain 83972 appears to prevent infection with UPEC strains in such patients despite the fact that this strain is unable to express the primary adhesins involved in UTI, viz. P and type 1 fimbriae. Here we investigated the growth characteristics of E. coli 83972 in human...
Phenotypic analysis of antibiotic resistant E. coli recovered from urban aquatic environment in Banda Aceh, Indonesia

Science.gov (United States)

Suhartono, S.; Ismail, Y. S.; Yulvizar, C.; Nursanty, R.; Mahyuddin, M.; Jannah, M.

2018-03-01

Of aquatic environment, antibiotic resistant bacteria, including total coliforms and E. coli disseminate and emerge at an alarming rate. The study aims to determine enumerate, isolate,E. coliand determine their antibiotic resistance and compare between those which were recovered from residentials and home industries in Banda Aceh and its surrounding area. The bacterial density and antibiotic susceptibility of total coliforms and E. coli were determined using Standard Total Coliform Multiple-Tube (MPN) Fermentation method and the disk diffusion method, respectively. Despite there was no significant difference of total coliforms and E. coli population between residentials and home industries (P > 0.05) in this study, their density as well as prevalence remained high in the water sample. This might expose serious health risks since the resistance might be easily spread acquired through horizontal gene transfer within the aquatic environment.
Determination of membrane disruption and genomic DNA binding of cinnamaldehyde to Escherichia coli by use of microbiological and spectroscopic techniques.

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He, Tian-Fu; Zhang, Zhi-Hong; Zeng, Xin-An; Wang, Lang-Hong; Brennan, Charles S

2018-01-01

This work was aimed to investigate the antibacterial action of cinnamaldehyde (CIN) against Escherichia coli ATCC 8735 (E. coli) based on membrane fatty acid composition analysis, alterations of permeability and cell morphology as well as interaction with genomic DNA. Analysis of membrane fatty acids using gas chromatography-mass spectrometry (GC-MS) revealed that the proportion of unsaturated fatty acids (UFA) and saturated fatty acids (SFA) were the major fatty acids in plasmic membrane, and their levels were significantly changed after exposure of E. coli to CIN at low concentrations. For example, the proportion of UFA decreased from 39.97% to 20.98%, while the relative content of SFA increased from 50.14% to 67.80% as E. coli was grown in increasing concentrations of CIN (from 0 to 0.88mM). Scanning electron microscopy (SEM) showed that the morphology of E. coli cells to be wrinkled, distorted and even lysed after exposure to CIN, which therefore decreased the cell viability. The binding of CIN to genomic DNA was probed using fluorescence, UV-Visible absorption spectra, circular dichroism, molecular modeling and atomic force microscopy (AFM). Results indicated that CIN likely bound to the minor groove of genomic DNA, and changed the secondary structure and morphology of this biomacromolecule. Therefore, CIN can be deem as a kind of natural antimicrobial agents, which influence both cell membrane and genomic DNA. Copyright © 2017 Elsevier B.V. All rights reserved.
Occurrence and sources of Escherichia coli in metropolitan St. Louis streams, October 2004 through September 2007

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Wilkison, Donald H.; Davis, Jerri V.

2010-01-01

The occurrence and sources of Escherichia coli (E. coli), one of several fecal indicator bacteria, in metropolitan St. Louis streams known to receive nonpoint source runoff, occasional discharges from combined and sanitary sewers, and treated wastewater effluent were investigated from October 2004 through September 2007. Three Missouri River sites, five Mississippi River sites, and six small basin tributary stream sites were sampled during base flow and storm events for the presence of E. coli and their sources. E. coli host-source determinations were conducted using local library based genotypic methods. Human fecal contamination in stream samples was additionally confirmed by the presence of Bacteroides thetaiotaomicron, an anaerobic, enteric bacterium with a high occurrence in, and specificity to, humans. Missouri River E. coli densities and loads during base flow were approximately 10 times greater than those in the Mississippi River above its confluence with the Missouri River. Although substantial amounts of E. coli originated from within the study area during base flow and storm events, considerable amounts of E. coli in the Missouri River, as well as in the middle Mississippi River sections downstream from its confluence with the Missouri River, originated in Missouri River reaches upstream from the study area. In lower Mississippi River reaches, bacteria contributions from the numerous combined and sanitary sewer overflows within the study area, as well as contributions from nonpoint source runoff, greatly increased instream E. coli densities. Although other urban factors cannot be discounted, average E. coli densities in streams were strongly correlated with the number of upstream combined and sanitary sewer overflow points, and the percentage of upstream impervious cover. Small basin sites with the greatest number of combined and sanitary sewer overflows (Maline Creek and the River des Peres) had larger E. coli densities, larger loads, and a greater
A genomically modified Escherichia coli strain carrying an orthogonal E. coli histidyl-tRNA synthetase•tRNAHis pair.

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Englert, Markus; Vargas-Rodriguez, Oscar; Reynolds, Noah M; Wang, Yane-Shih; Söll, Dieter; Umehara, Takuya

2017-11-01

Development of new aminoacyl-tRNA synthetase (aaRS)•tRNA pairs is central for incorporation of novel non-canonical amino acids (ncAAs) into proteins via genetic code expansion (GCE). The Escherichia coli and Caulobacter crescentus histidyl-tRNA synthetases (HisRS) evolved divergent mechanisms of tRNA His recognition that prevent their cross-reactivity. Although the E. coli HisRS•tRNA His pair is a good candidate for GCE, its use in C. crescentus is limited by the lack of established genetic selection methods and by the low transformation efficiency of C. crescentus. E. coli was genetically engineered to use a C. crescentus HisRS•tRNA His pair. Super-folder green fluorescent protein (sfGFP) and chloramphenicol acetyltransferase (CAT) were used as reporters for read-through assays. A library of 313 ncAAs coupled with the sfGFP reporter system was employed to investigate the specificity of E. coli HisRS in vivo. A genomically modified E. coli strain (named MEOV1) was created. MEVO1 requires an active C. crescentus HisRS•tRNA His pair for growth, and displays a similar doubling time as the parental E. coli strain. sfGFP- and CAT-based assays showed that the E. coli HisRS•tRNA His pair is orthogonal in MEOV1 cells. A mutation in the anticodon loop of E. coli tRNA His CUA elevated its suppression efficiency by 2-fold. The C. crescentus HisRS•tRNA His pair functionally complements an E. coli ΔhisS strain. The E. coli HisRS•tRNA His is orthogonal in MEOV1 cells. E. coli tRNA His CUA is an efficient amber suppressor in MEOV1. We developed a platform that allows protein engineering of E. coli HisRS that should facilitate GCE in E. coli. This article is part of a Special Issue entitled "Biochemistry of Synthetic Biology - Recent Developments" Guest Editor: Dr. Ilka Heinemann and Dr. Patrick O'Donoghue. Copyright © 2017 Elsevier B.V. All rights reserved.
Attachment of Escherichia coli and enterococci to particles in runoff.

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Soupir, Michelle L; Mostaghimi, Saied; Dillaha, Theo

2010-01-01

Association of Escherichia coli and enterococci with particulates present in runoff from erodible soils has important implications for modeling the fate and transport of bacteria from agricultural sources and in the selection of management practices to reduce bacterial movement to surface waters. Three soils with different textures were collected from the Ap horizon (silty loam, silty clay loam, and loamy fine sand), placed in portable box plots, treated with standard cowpats, and placed under a rainfall simulator. Rainfall was applied to the plots until saturation-excess flow occurred for 30 min, and samples were collected 10, 20, and 30 min after initiation of the runoff event. The attachment of E. coli and enterococci to particles present in runoff was determined by a screen filtration and centrifugation procedure. Percentage of E. coli and enterococci attached to particulates in runoff ranged from 28 to 49%, with few statistically significant differences in attachment among the three soils. Similar partitioning release patterns were observed between E. coli and enterococci from the silty loam (r = 0.57) and silty clay loam soils (r = 0.60). At least 60% of all attached E. coli and enterococci were associated particles within an 8- to 62-microm particle size category. The results indicate that the majority of fecal bacteria attach to and are transported with manure colloids in sediment-laden flow regardless of the soil texture.
Controlling cell volume for efficient PHB production by Halomonas.

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Jiang, Xiao-Ran; Yao, Zhi-Hao; Chen, Guo-Qiang

2017-11-01

Bacterial morphology is decided by cytoskeleton protein MreB and cell division protein FtsZ encoded by essential genes mreB and ftsZ, respectively. Inactivating mreB and ftsZ lead to increasing cell sizes and cell lengths, respectively, yet seriously reduce cell growth ability. Here we develop a temperature-responsible plasmid expression system for compensated expression of relevant gene(s) in mreB or ftsZ disrupted recombinants H. campaniensis LS21, allowing mreB or ftsZ disrupted recombinants to grow normally at 30°C in a bioreactor for 12h so that a certain cell density can be reached, followed by 36h cell size expansions or cell shape elongations at elevated 37°C at which the mreB and ftsZ encoded plasmid pTKmf failed to replicate in the recombinants and thus lost themselves. Finally, 80% PHB yield increase was achieved via controllable morphology manipulated H. campaniensis LS21. It is concluded that controllable expanding cell volumes (widths or lengths) provides more spaces for accumulating more inclusion body polyhydroxybutyrate (PHB) and the resulting cell gravity precipitation benefits the final separation of cells and product during downstream. Copyright © 2017 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.
Antibiotic resistance profile and virulence genes of uropathogenic Escherichia coli isolates in relation to phylogeny.

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Adib, N; Ghanbarpour, R; Solatzadeh, H; Alizade, H

2014-03-01

Escherichia coli (E. coli) strains are the major cause of urinary tract infections (UTI) and belong to the large group of extra-intestinal pathogenic E. coli. The purposes of this study were to determine the antibiotic resistance profile, virulence genes and phylogenetic background of E. coli isolates from UTI cases. A total of 137 E. coli isolates were obtained from UTI samples. The antimicrobial susceptibility of confirmed isolates was determined by disk diffusion method against eight antibiotics. The isolates were examined to determine the presence and prevalence of selected virulence genes including iucD, sfa/focDE, papEF and hly. ECOR phylo-groups of isolates were determined by detection of yjaA and chuA genes and fragment TspE4.C2. The antibiogram results showed that 71% of the isolates were resistant to cefazolin, 60.42% to co-trimoxazole, 54.16% to nalidixic acid, 36.45% to gentamicin, 29.18% to ciprofloxacin, 14.58% to cefepime, 6.25% to nitrofurantoin and 0.00% to imipenem. Twenty-two antibiotic resistance patterns were observed among the isolates. Virulence genotyping of isolates revealed that 58.39% isolates had at least one of the four virulence genes. The iucD gene was the most prevalent gene (43.06%). The other genes including sfa/focDE, papEF and hly genes were detected in 35.76%, 18.97% and 2.18% isolates, respectively. Nine combination patterns of the virulence genes were detected in isolates. Phylotyping of 137 isolates revealed that the isolates fell into A (45.99%), B1 (13.14%), B2 (19.71%) and D (21.16%) groups. Phylotyping of multidrug resistant isolates indicated that these isolates are mostly in A (60.34%) and D (20.38%) groups. In conclusion, the isolates that possessed the iucD, sfa/focDE, papEF and hly virulence genes mostly belonged to A and B2 groups, whereas antibiotic resistant isolates were in groups A and D. Escherichia coli strains carrying virulence factors and antibiotic resistance are distributed in specific phylogenetic
Serogroups and antimicrobial susceptibility among Escherichia coli isolated from farmed mink (Mustela vison Schreiber) in Denmark

DEFF Research Database (Denmark)

Vulfson, L.; Pedersen, Karl; Chriel, M.

2001-01-01

Escherichia coli is commonly found in outbreaks of diarrhoea in mink during the production season although its role as a primary causal organism remains unclear. The present study was undertaken to determine the serogroups and antimicrobial susceptibility of E. coli isolates from healthy and diar......Escherichia coli is commonly found in outbreaks of diarrhoea in mink during the production season although its role as a primary causal organism remains unclear. The present study was undertaken to determine the serogroups and antimicrobial susceptibility of E. coli isolates from healthy...... diseased. All isolates were serotyped and MICs were determined for nine antimicrobial compounds. Non-haemolytic isolates numbered 147, whereas 63 were haemolytic. Both haemolytic and non-haemolytic isolates were isolated from both healthy and diseased animals. A wide range of serogroups was detected...... among the six mink farms, for tetracycline (0-16.4%. average 21.9), ampicillin (2.9-50.0%. average 23.3), spectinomycin (8.0-35.7%. average 21.9), sulfamethoxazole (8.6-57.7%. average 30.0) and trimethoprim (0-35.7%. average 9.5). Resistance to tetracycline was statistically more prevalent among...
Dietary N-Carbamylglutamate Supplementation Boosts Intestinal Mucosal Immunity in Escherichia coli Challenged Piglets.

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Fengrui Zhang

Full Text Available N-carbamylglutamate (NCG has been shown to enhance performance in neonatal piglets. However, few studies have demonstrated the effect of NCG on the intestinal mucosal barrier. This study was conducted to determine the effects of dietary NCG supplementation on intestinal mucosal immunity in neonatal piglets after an Escherichia coli (E. coli challenge. New-born piglets (4 d old were assigned randomly to one of four treatments (n = 7, including (I sham challenge, (II sham challenge +50 mg/kg NCG, (III E. coli challenge, and (IV E. coli challenge +50 mg/kg NCG. On d 8, pigs in the E. coli challenge groups (III and IV were orally challenged with 5 mL of E. coli K88 (10(8 CFU/mL, whereas pigs in the sham challenge groups (I and II were orally dosed with an equal volume of water. On d 13, all piglets were sacrificed, and samples were collected and examined. The results show that average daily gain in the E. coli challenged piglets (III and IV was decreased (PE.coli<0.05. However, it tended to be higher in the NCG treated piglets (II and IV. Ileum secretory IgA, as well as IFN-γ, IL-2, IL-4 and IL-10 in ileal homogenates, were increased in E. coli challenged piglets (III and IV. Similarly, ileum SIgA and IL-10 levels, and CD4(+ percentage in NCG treated piglets (II and IV were higher than no-NCG treated piglets (PNCG<0.05. However, the IL-2 level was only decreased in the piglets of E. coli challenge + NCG group (IV compared with E. coli challenge group (III (P<0.05. No change in the IL-2 level of the sham challenged piglets (III was observed. In conclusion, dietary NCG supplementation has some beneficial effects on intestinal mucosal immunity in E. coli challenged piglets, which might be associated with stimulated lymphocyte proliferation and cytokine synthesis. Our findings have an important implication that NCG may be used to reduce diarrhea in neonatal piglets.
Silver nanoparticle-E. coli colloidal interaction in water and effect on E. coli survival.

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Dror-Ehre, A; Mamane, H; Belenkova, T; Markovich, G; Adin, A

2009-11-15

Silver nanoparticles exhibit antibacterial properties via bacterial inactivation and growth inhibition. The mechanism is not yet completely understood. This work was aimed at elucidating the effect of silver nanoparticles on inactivation of Escherichia coli, by studying particle-particle interactions in aqueous suspensions. Stable, molecularly capped, positively or negatively charged silver nanoparticles were mixed at 1 to 60microgmL(-1) with suspended E. coli cells to examine their effect on inactivation of the bacteria. Gold nanoparticles with the same surfactant were used as a control, being of similar size but made up of a presumably inert metal. Log reduction of 5log(10) and complete inactivation were obtained with the silver nanoparticles while the gold nanoparticles did not show any inactivation ability. The effect of molecularly capped nanoparticles on E. coli survival was dependent on particle number. Log reduction of E. coli was associated with the ratio between the number of nanoparticles and the initial bacterial cell count. Electrostatic attraction or repulsion mechanisms in silver nanoparticle-E. coli cell interactions did not contribute to the inactivation process.
Assessment of the efficiency of ColiSure™ for coliforms Escherichia coli enumeration in pasteurizad milk / Avaliação do desempenho do ColiSure™ na enumeração de coliformes totais e Escherichia coli em leite pasteurizado

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Elsa Helena Walter de Santana

2000-12-01

Full Text Available In the dairy industry the coliforms detection can he used as indicative of hygiene production of the raw milk and the contamination after-pasteurization. The traditional methods for the enumeration of the total and faecal coliforms are laborious and needs an incubation time of 96 hours. Rapid methods for detection of these microorganisms have been developed and among them the ColsSuroit is a rapid method that gives results in 24 hours and involves defined substrates for simultaneous determination of total conforms and E. coli in water based in specific enzymatic reactions of these microorganisms. The objective of this study was to evaluate its utilization in milk. Ninety-five samples of pasteurized milk were collected from the markets in Londrina city, Parana and analyzed by the Most Probable Number (NMP enumeration using the Brilliant Green Bile Lactose Broth (BGBL and ColiSure™. There was a correlation of 0.80 betwee-n the mediums when the incubation time was 43 hours for total conforms. The low down occurrence of E. coffin the analyzed samples made impossible to comparate the performance of methods for this microorganism. Compfementary analysis showed a greater sensibility and especifity of the ColiSure™ in comparation with the BGBL. The CofiSure™ can be indicated as a substitute for the traditional method, with the advantage to be faster and easier.Na indústria láctea a detecção de microrganismos do grupo coliformes é utilizada como indicativo da higiene na produção do leite e de contaminação pós-pasteurizaçüo. Os métodos tradicionais para a enumeração de coliformes totais e fecais são trabalhosos, com tempo de incubação longo, de até 96 horas. Métodos rápidos para a detecção destes microrganismos têm sido desenvolvidos na área de microbiologia de alimentos. O ColiSure™ é um método rápido, que fornece resultados simultaneamente para a presença ou a ausência de coliformes totais e Escherichia coli em �
Efficacy of a Blend of Sulfuric Acid and Sodium Sulfate against Shiga Toxin-Producing Escherichia coli, Salmonella, and Nonpathogenic Escherichia coli Biotype I on Inoculated Prerigor Beef Surface Tissue.

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Scott-Bullard, Britteny R; Geornaras, Ifigenia; Delmore, Robert J; Woerner, Dale R; Reagan, James O; Morgan, J Bred; Belk, Keith E

2017-12-01

A study was conducted to investigate the efficacy of a sulfuric acid-sodium sulfate blend (SSS) against Escherichia coli O157:H7, non-O157 Shiga toxin-producing E. coli (STEC), Salmonella, and nonpathogenic E. coli biotype I on prerigor beef surface tissue. The suitability of using the nonpathogenic E. coli as a surrogate for in-plant validation studies was also determined by comparing the data obtained for the nonpathogenic inoculum with those for the pathogenic inocula. Prerigor beef tissue samples (10 by 10 cm) were inoculated (ca. 6 log CFU/cm 2 ) on the adipose side in a laboratory-scale spray cabinet with multistrain mixtures of E. coli O157:H7 (5 strains), non-O157 STEC (12 strains), Salmonella (6 strains), or E. coli biotype I (5 strains). Treatment parameters evaluated were two SSS pH values (1.5 and 1.0) and two spray application pressures (13 and 22 lb/in 2 ). Untreated inoculated beef tissue samples served as controls for initial bacterial populations. Overall, the SSS treatments lowered inoculated (6.1 to 6.4 log CFU/cm 2 ) bacterial populations by 0.6 to 1.5 log CFU/cm 2 (P SSS was applied to samples inoculated with any of the tested E. coli inocula; however, solution pH did have a significant effect (P SSS was applied to samples inoculated with Salmonella. Results indicated that the response of the nonpathogenic E. coli inoculum to the SSS treatments was similar (P ≥ 0.05) to that of the pathogenic inocula tested, making the E. coli biotype I strains viable surrogate organisms for in-plant validation of SSS efficacy on beef. The application of SSS at the tested parameters to prerigor beef surface tissue may be an effective intervention for controlling pathogens in a commercial beef harvest process.
Presence and Antimicrobial Resistance of Escherichia coli in Ready-to-Eat Foods in Shaanxi, China.

Science.gov (United States)

Baloch, Allah Bux; Yang, Hua; Feng, Yuqing; Xi, Meili; Wu, Qian; Yang, Qinhao; Tang, Jingsi; He, Xiangxiang; Xiao, Yingping; Xia, Xiaodong

2017-03-01

The aim of this study was to determine the presence and characteristics of Escherichia coli in ready-to-eat (RTE) foods. A total of 300 RTE foods samples were collected in Shaanxi Province, People's Republic of China: 50 samples of cooked meat, 165 samples of vegetable salad, 50 samples of cold noodles, and 35 samples of salted boiled peanuts. All samples were collected during summer (in July to October) 2011 and 2012 and surveyed for the presence of E. coli . E. coli isolates recovered were classified by phylogenetic typing using a PCR assay. The presence of Shiga toxin genes 1 (stx 1 ) and 2 (stx 2 ) was determined for these E. coli isolates by PCR, and all isolates were analyzed for antimicrobial susceptibility and the presence of class 1 integrons. Overall, 267 (89.0%) RTE food samples were positive for E. coli : 49 cold noodle, 46 cooked meat, 150 salad vegetable, and 22 salted boiled peanut samples. Of the 267 E. coli isolates, 73.0% belong to phylogenetic group A, 12.4% to group B1, 6.4% to group B2, and 8.2% to group D. All isolates were negative for both Shiga toxin genes. Among the isolates, 74.2% were resistant to at least one antimicrobial agent, and 17.6% were resistant to three or more antimicrobial agents. Resistance to ampicillin (75.6% of isolates) and tetracycline (73.1% of isolates) was most frequently detected; 26.2% of E. coli isolates and 68.8% of multidrug-resistant E. coli isolates were positive for class 1 integrons. All isolates were sensitive to amikacin. Our findings indicate that RTE foods in Shaanxi were commonly contaminated with antibiotic-resistant E. coli , which may pose a risk for consumer health and for transmission of antibiotic resistance. Future research is warranted to track the contamination sources and develop appropriate steps that should be taken by government, industry, and retailers to reduce microbial contamination in RTE foods.
Genetic diversity and antimicrobial resistance of Escherichia coli from human and animal sources uncovers multiple resistances from human sources.

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A Mark Ibekwe

Full Text Available Escherichia coli are widely used as indicators of fecal contamination, and in some cases to identify host sources of fecal contamination in surface water. Prevalence, genetic diversity and antimicrobial susceptibility were determined for 600 generic E. coli isolates obtained from surface water and sediment from creeks and channels along the middle Santa Ana River (MSAR watershed of southern California, USA, after a 12 month study. Evaluation of E. coli populations along the creeks and channels showed that E. coli were more prevalent in sediment compared to surface water. E. coli populations were not significantly different (P = 0.05 between urban runoff sources and agricultural sources, however, E. coli genotypes determined by pulsed-field gel electrophoresis (PFGE were less diverse in the agricultural sources than in urban runoff sources. PFGE also showed that E. coli populations in surface water were more diverse than in the sediment, suggesting isolates in sediment may be dominated by clonal populations.Twenty four percent (144 isolates of the 600 isolates exhibited resistance to more than one antimicrobial agent. Most multiple resistances were associated with inputs from urban runoff and involved the antimicrobials rifampicin, tetracycline, and erythromycin. The occurrence of a greater number of E. coli with multiple antibiotic resistances from urban runoff sources than agricultural sources in this watershed provides useful evidence in planning strategies for water quality management and public health protection.

ANTIBACTERIAL ACTIVITY OF SOME WILD MEDICAL PLANTS EXTRACT TO ANTIBIOTIC RESISTANT ESCHERICHIA COLI

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Lukáš Hleba

2013-02-01

Full Text Available Antibiotics are probably the most successful family of drugs so far developed for improving human health. Because of increasing resistance to antibiotics of many bacteria, plant extracts and plant compounds are of new interest as antiseptics and antimicrobial agents in medicine. In this study, we researched antimicrobial effects of extracts of some medical plants (Tussilagofarfara, Equisetum arvense, Sambucusnigra, Aesculushippocastanumand Taraxacumofficinale from Slovakia to antibiotic resistant and antibiotic sensitive bacteria isolated from milk of cows and mare, which were breeded in different conditions. Microorganisms which were used in this experiment we isolated from milk from conventional breeding of cows (tenE. coli strains and from ecological breeding of Lipicanmare (tenE. coli strains by sterile cotton swabs. For antibiotic susceptibility testing was used disc diffusion method according by EUCAST. After dried at room temperature we weighed 50 g of crushed medical plants (parts and it were to extract in 400 ml methanol for two weeks at room temperature. For antimicrobial susceptibility testing of medical plants extract blank discs with 6 mm diameter disc diffusion method was used. We determined that all Escherichia coli strains isolated from milk of conventional breeding of cows were resistant to ampicillin and chloramphenicol. We determined that all tested ampicillin and chloramphenicol resistant E. coli strains isolated from conventional breeding of cow showed susceptibility to all used medical plants extracts. In difference, we determined that antibiotic susceptible E. coli strains isolated from ecological breeding of Lipicanmare were susceptible to Tussilagofarfara extract only. From these results we could be conclude some observations, which could be important step in treatment of bacterial infections caused by antibiotic resistant bacteria and it could be important knowledge for treatment of livestock in conventional breeding
PENGARUH PERASAN DAUN BELIMBING WULUH (Averrhoa bilimbi TERHADAP PERTUMBUHAN BAKTERI Escherichia coli PATOGEN

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Fitrotin Azizah

2017-12-01

abstract (Averrhoa bilimbi is one of the plants that can be used as an antibacterial, good flowers, stems, leaves and stems have benefits and efficacy. Chemical constituents of the leaves starfruit are tannins, flavonoids, saponins. The active ingredient in the leaves starfruit is tannin. Escherichia coli is a bacterium that causes diarrhea. From the above discussion, the authors raised the theme of Influence starfruit juice of the leaves on the growth of pathogenic E. coli bacteria. Formulation of the problem researchers is whether there is influence starfruit juice of the leaves on the growth of Escherichia coli pathogens. This study aims to determine the concentration that could inhibit and kill Esherichia coli Escherichia coli. This research is experimental. The sample used is leaf green starfruit not so young in a fresh state taken in the area around the boarding author Sutorejo 11B stay. In this study, the sample size for each treatment as much as 3 100%, 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, 10% and C (control. Independent variables are starfruit juice of the leaves, while the dependent variable growth of Escherichia coli. When the study carried out in January and July 2012. Data on the effect of starfruit juice of the leaves on the growth of Escherichia coli tested by laboratory examination and data collection techniques using Chi-Square 0:05. Based on the results it appears that at a concentration of 100% and 90% were able to kill the bacteria Escherichia coli, whereas the inhibitory power ranging from a concentration of 80%, 70%, 60%, 50%, 40%, 30%, 20%, 10%. From Chi-Square test was obtained λ2 count coli pathogenic bacteria. Keyword : Leaves starfruit, E. Coli
Characterisation of commensal Escherichia coli isolated from apparently healthy cattle and their attendants in Tanzania

DEFF Research Database (Denmark)

Madoshi, Balichene; Kudirkiene, Egle; Mtambo, Madundo

2016-01-01

attendants on cattle farms in Tanzania were investigated. Seventeen E. coli genomes representing different ERIC-PCR types of commensal E. coli were sequenced in order to determine their possible importance as a reservoir for both antimicrobial resistance genes and virulence factors. Both human and cattle...... isolates were highly resistant to tetracycline (40.8% and 33.1%), sulphamethazole-trimethoprim (49.0% and 8.8%) and ampicillin (44.9% and 21.3%). However, higher proportion of resistant E. coli and higher frequency of resistance to more than two antimicrobials was found in isolates from cattle attendants...
Transport of Escherichia coli and F-RNA bacteriophages in a 5 m column of saturated pea gravel

Science.gov (United States)

Sinton, Lester W.; Mackenzie, Margaret L.; Karki, Naveena; Braithwaite, Robin R.; Hall, Carollyn H.; Flintoft, Mark J.

2010-09-01

The relative transport and attenuation of bacteria, bacteriophages, and bromide was determined in a 5 m long × 0.3 m diameter column of saturated pea gravel. The velocity ( V), longitudinal dispersivity ( αx) and total removal rate ( λ) were calculated from the breakthrough curves at 1 m, 3 m, and 5 m, at a flow rate of 32 L h - 1 . Inactivation ( μ) rates were determined in survival chambers. Two pure culture experiments with Escherichia coli J6-2 and F-RNA phage MS2 produced an overall V ranking of E. coli J6-2 > MS2 > bromide, consistent with velocity enhancement, whereby larger particles progressively move into faster, central streamlines of saturated pores. Removal rates were near zero for MS2, but were higher for E. coli J6-2. In two sewage experiments, E. coli and F-RNA phage Vs were similar (but > bromide). This was attributed to phage adsorption to colloids similar in size to E. coli cells. Sewage phage removal rates were higher than for the pure MS2 cultures. The application of filtration theory suggested that, whereas free phage were unaffected by settling, this was the primary removal mechanism for the colloid-associated phage. However, cultured and sewage E. coli removal rates were similar, suggesting the dominance of free E. coli cells in the sewage. When MS2 was attached to kaolin particles, it was transported faster than free MS2, but at similar rates to sewage phage. The μ values indicated little contribution of inactivation to removal of either cultured or sewage microorganisms. The results showed the importance of association with colloids in determining the relative transport of bacteria and viruses in gravels.
MOLECULAR-PHYLOGENETIC CHARACTERIZATION AND ANTIMICROBIAL RESISTANCE OF Escherichia coli ISOLATED FROM GOATS WITH DIARRHEA

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Rodrigo Almeida Guimarães

2015-10-01

Full Text Available Neonatal diarrhea determines significant changes in feed conversion, causing productivity loss in caprine herds. The antimicrobial resistance in bacteria is characterized as an important public health issue; therefore, Escherichia coli may be characterized as an important pathogen due to expressing virulence mechanisms responsible for significant clinical conditions in humans and animals. The present study evaluated the presence of E. coli among 117 caprine fecal samples and analyzed the isolates for antimicrobial resistance. Suggestive colonies were submitted to biochemical screening followed by genotypic group determination and phylogenetic analysis; further, the samples were submitted to antimicrobials susceptibility test. E. coli, Salmonella spp, Shigella sonnei and Enterobacter aerogenes were identified. E. coli isolates were phylogenetically classified as B2 (9/39, D (19/39, B1 (7/39 e A (4/29 groups. The analysis of the isolates also revealed the presence of K99 (04/39 and Stx (02/39 virulence factors. Antimicrobial susceptibility test revealed sensitive isolates to Chloramphenicol, Streptomycin, Amoxicillin and Ciprofloxacin, being all resistant to Lincomycin, Vancomycin and Penicillin. The results support the need of establishing restricted protocols for antimicrobial use, a fundamental procedure for health improvement in Brazilian caprine herds.
Trade-Offs of Escherichia coli Adaptation to an Intracellular Lifestyle in Macrophages.

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M Azevedo

Full Text Available The bacterium Escherichia coli exhibits remarkable genomic and phenotypic variation, with some pathogenic strains having evolved to survive and even replicate in the harsh intra-macrophage environment. The rate and effects of mutations that can cause pathoadaptation are key determinants of the pace at which E. coli can colonize such niches and become pathogenic. We used experimental evolution to determine the speed and evolutionary paths undertaken by a commensal strain of E. coli when adapting to intracellular life. We estimated the acquisition of pathoadaptive mutations at a rate of 10-6 per genome per generation, resulting in the fixation of more virulent strains in less than a hundred generations. Whole genome sequencing of independently evolved clones showed that the main targets of intracellular adaptation involved loss of function mutations in genes implicated in the assembly of the lipopolysaccharide core, iron metabolism and di- and tri-peptide transport, namely rfaI, fhuA and tppB, respectively. We found a substantial amount of antagonistic pleiotropy in evolved populations, as well as metabolic trade-offs, commonly found in intracellular bacteria with reduced genome sizes. Overall, the low levels of clonal interference detected indicate that the first steps of the transition of a commensal E. coli into intracellular pathogens are dominated by a few pathoadaptive mutations with very strong effects.
Isolation and serological identification of enteropathogenic Escherichia coli in pasteurized milk in Brazil

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Zoraide N da Silva

2001-08-01

Full Text Available OBJECTIVE: To evaluate the microbiological quality of pasteurized milk commercialized in Rio de Janeiro, Brazil, and determine serologically enteropathogenic Escherichia coli (EPEC strains in E. coli isolates obtained from milk samples. METHODS: Ninety samples of pasteurized milk -- types B and C -- of three different commercial brands, purchased in supermarkets and bakeries in Rio de Janeiro, were examined. The amount of total and fecal coliform bacteria was estimated using the Most Probable Number technique. Mesophilic, psychrotrophic, and thermoduric microorganism counts were determined by the Standard Plate Count technique. Isolation and identification of E. coli were carried out using conventional physiological tests. Commercial antisera were used for serological characterization of EPEC. RESULTS: The three milk brands analyzed revealed bacterial counts above the regulated values of the Brazilian government. It was found that among 208 strains of E. coli isolated, 46 (22.1% were serologically classified as EPEC. The most common EPEC serogroup was O55 (15.2%. CONCLUSIONS: Though recent studies on virulence factors indicate that not all strains serologically classified as EPEC are able to attaching/effacing lesion, it is believed that the isolation of EPEC serogroups from pasteurized milk represent a potential risk for children, as well as an indicative of the presence of other enteropathogens.
Inactivation of the Escherichia coli chromosome during growth after ultraviolet irradiation

International Nuclear Information System (INIS)

Medic-Petranovic, M.; Trgovcevic, Z.; Novak, D.; Petranovic, D.

1977-01-01

Cells of the repair-proficient E.coli AB1157 strain and its lysogenic E.coli AB1157 (lambda c1857 ind) counterpart have been UV irradiated in an attempt to define when and why cells that are destined to die reach their biological end-point in the course of post-irradiation incubation. The thermo-inducibility of the lambdac1857 ind lysogens was first determined, since this reflects the functional integrity of the pro-viral part of the bacterial chromosome and that of the bacterial cytoplasm. The capacity (i.e. the ability of the irradiated cells to support growth of the unirradiated phage) was then determined, since this depends on the functional integrity of the bacterial cytoplasm. A progressive decrease in the ability of the lysogens to be heat-induced always preceded the decrease in capacity for the phage growth. The results strongly suggest that wild-type E.coli cells destined to die after exposure to moderate doses of UV-light reach their end point within 4 hours of post-irradiation incubation, probably as a result of the functional failure of the whole chromosome. (U.K.)
Multiplex real-time PCR assay for detection of Escherichia coli O157:H7 and screening for non-O157 Shiga toxin-producing E. coli.

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Li, Baoguang; Liu, Huanli; Wang, Weimin

2017-11-09

Shiga toxin-producing Escherichia coli (STEC), including E. coli O157:H7, are responsible for numerous foodborne outbreaks annually worldwide. E. coli O157:H7, as well as pathogenic non-O157:H7 STECs, can cause life-threating complications, such as bloody diarrhea (hemolytic colitis) and hemolytic-uremic syndrome (HUS). Previously, we developed a real-time PCR assay to detect E. coli O157:H7 in foods by targeting a unique putative fimbriae protein Z3276. To extend the detection spectrum of the assay, we report a multiplex real-time PCR assay to specifically detect E. coli O157:H7 and screen for non-O157 STEC by targeting Z3276 and Shiga toxin genes (stx1 and stx2). Also, an internal amplification control (IAC) was incorporated into the assay to monitor the amplification efficiency. The multiplex real-time PCR assay was developed using the Life Technology ABI 7500 System platform and the standard chemistry. The optimal amplification mixture of the assay contains 12.5 μl of 2 × Universal Master Mix (Life Technology), 200 nM forward and reverse primers, appropriate concentrations of four probes [(Z3276 (80 nM), stx1 (80 nM), stx2 (20 nM), and IAC (40 nM)], 2 μl of template DNA, and water (to make up to 25 μl in total volume). The amplification conditions of the assay were set as follows: activation of TaqMan at 95 °C for 10 min, then 40 cycles of denaturation at 95 °C for 10 s and annealing/extension at 60 °C for 60 s. The multiplex assay was optimized for amplification conditions. The limit of detection (LOD) for the multiplex assay was determined to be 200 fg of bacterial DNA, which is equivalent to 40 CFU per reaction which is similar to the LOD generated in single targeted PCRs. Inclusivity and exclusivity determinants were performed with 196 bacterial strains. All E. coli O157:H7 (n = 135) were detected as positive and all STEC strains (n = 33) were positive for stx1, or stx2, or stx1 and stx2 (Table 1). No cross reactivity was detected with Salmonella
Structure of the Escherichia coli RNA polymerase α subunit C-terminal domain

International Nuclear Information System (INIS)

Lara-González, Samuel; Birktoft, Jens J.; Lawson, Catherine L.

2010-01-01

The crystal structure of the dimethyllysine derivative of the E. coli RNA polymerase α subunit C-terminal domain is reported at 2.0 Å resolution. The α subunit C-terminal domain (αCTD) of RNA polymerase (RNAP) is a key element in transcription activation in Escherichia coli, possessing determinants responsible for the interaction of RNAP with DNA and with transcription factors. Here, the crystal structure of E. coli αCTD (α subunit residues 245–329) determined to 2.0 Å resolution is reported. Crystals were obtained after reductive methylation of the recombinantly expressed domain. The crystals belonged to space group P2 1 and possessed both pseudo-translational symmetry and pseudo-merohedral twinning. The refined coordinate model (R factor = 0.193, R free = 0.236) has improved geometry compared with prior lower resolution determinations of the αCTD structure [Jeon et al. (1995 ▶), Science, 270, 1495–1497; Benoff et al. (2002 ▶), Science, 297, 1562–1566]. An extensive dimerization interface formed primarily by N- and C-terminal residues is also observed. The new coordinates will facilitate the improved modeling of αCTD-containing multi-component complexes visualized at lower resolution using X-ray crystallography and electron-microscopy reconstruction
Protozoan Predation of Escherichia coli O157:H7 Is Unaffected by the Carriage of Shiga Toxin-Encoding Bacteriophages.

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Carrie E Schmidt

Full Text Available Escherichia coli O157:H7 is a food-borne bacterium that causes hemorrhagic diarrhea and hemolytic uremic syndrome in humans. While cattle are a known source of E. coli O157:H7 exposure resulting in human infection, environmental reservoirs may also be important sources of infection for both cattle and humans. Bacteriophage-encoded Shiga toxins (Stx carried by E. coli O157:H7 may provide a selective advantage for survival of these bacteria in the environment, possibly through their toxic effects on grazing protozoa. To determine Stx effects on protozoan grazing, we co-cultured Paramecium caudatum, a common ciliate protozoon in cattle water sources, with multiple strains of Shiga-toxigenic E. coli O157:H7 and non-Shiga toxigenic cattle commensal E. coli. Over three days at ambient laboratory temperature, P. caudatum consistently reduced both E. coli O157:H7 and non-Shiga toxigenic E. coli populations by 1-3 log cfu. Furthermore, a wild-type strain of Shiga-toxigenic E. coli O157:H7 (EDL933 and isogenic mutants lacking the A subunit of Stx 2a, the entire Stx 2a-encoding bacteriophage, and/or the entire Stx 1-encoding bacteriophage were grazed with similar efficacy by both P. caudatum and Tetrahymena pyriformis (another ciliate protozoon. Therefore, our data provided no evidence of a protective effect of either Stx or the products of other bacteriophage genes on protozoan predation of E. coli. Further research is necessary to determine if the grazing activity of naturally-occurring protozoa in cattle water troughs can serve to decrease cattle exposure to E. coli O157:H7 and other Shiga-toxigenic E. coli.
Growth and survival of Escherichia coli and enterococci populations in the macro-alga Cladophora (Chlorophyta).

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Byappanahalli, Muruleedhara N; Shively, Dawn A; Nevers, Meredith B; Sadowsky, Michael J; Whitman, Richard L

2003-11-01

The macro-alga Cladophora glomerata is found in streams and lakes worldwide. High concentrations of Escherichia coli and enterococci have been reported in Cladophora along the Lake Michigan shore. The objective of this study was to determine if Cladophora supported growth of these indicator bacteria. Algal leachate readily supported in vitro multiplication of E. coli and enterococci, suggesting that leachates contain necessary growth-promoting substances. Growth was directly related to the concentration of algal leachate. E. coli survived for over 6 months in dried Cladophora stored at 4 degrees C; residual E. coli grew after mat rehydration, reaching a carrying capacity of 8 log CFU g(-1) in 48 h. Results of this study also show that the E. coli strains associated with Cladophora are highly related; in most instances they are genetically different from each other, suggesting that the relationship between E. coli and Cladophora may be casual. These findings indicate that Cladophora provides a suitable environment for indicator bacteria to persist for extended periods and to grow under natural conditions.
Prognostic value of low blood glucose at the presentation of E. coli bacteremia.

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Alamgir, Shamsuddin; Volkova, Natalia B; Peterson, Michael W

2006-11-01

Septicemia is the tenth leading cause of death in the United States, and Escherichia coli is the most common isolate in blood cultures. Low blood glucose is a known complication of sepsis. The prognostic role of low blood glucose in E. coli bacteremia is unknown. The study's objective was to identify the incidence of low blood glucose at the presentation of E. coli bacteremia and determine its influence on prognosis and outcome. A retrospective cohort study was conducted in university-affiliated community hospitals. Subjects were consecutive patients diagnosed with E. coli bacteremia between 1997 and 2003. We identified 1060 patients with documented E. coli bacteremia. We excluded 105 patients who were younger than 18 years old or pregnant. We recorded demographic characteristics, discharge diagnosis, and outcome. Among the 955 patients with E. coli bacteremia, the average age was 64+/-19.4 years. Overall, 4.6% had documented low blood glucose (blood glucose <70 mg/dL) at presentation. The incidence of low blood glucose was the same in diabetic and nondiabetic patients. Patients with low blood glucose had a 4.7 times higher risk of death compared to patients with non-low blood glucose. Race, age, sex, and diabetes had no influence on survival. Gastrointestinal and genitourinary sources for E. coli bacteremia were more commonly associated with low blood glucose (P <.001). The study was limited to E. coli-positive blood cultures and to the one hospital system. Low blood glucose is present at the onset of E. coli bacteremia in 4.6% of patients. This represents a potentially large number of patients because E. coli is the most common blood culture isolate. Low blood glucose predicts poor outcome, especially in patients with abnormal hepatic and renal function. Low blood glucose should be considered an early clinical sign of E. coli bacteremia and aggressive therapy should be instituted to potentially save lives.
Antibiotic Resistance in Escherichia coli from Pigs in Organic and Conventional Farming in Four European Countries.

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Österberg, Julia; Wingstrand, Anne; Nygaard Jensen, Annette; Kerouanton, Annaelle; Cibin, Veronica; Barco, Lisa; Denis, Martine; Aabo, Sören; Bengtsson, Björn

2016-01-01

Organic pig production differs in many ways from conventional production of pigs, e.g., in antibiotic use, herd structure, feeding regimes, access to outdoor areas and space allowance per pig. This study investigated if these differences result in a lower occurrence of antibiotic resistance in organic slaughter pigs in Denmark, France, Italy and Sweden. Samples were taken from the colon content and/or faeces and minimum inhibitory concentrations (MIC) of ten antibiotics were determined in isolates of Escherichia coli. In addition, the proportion of tetracycline (TET) resistant E. coli in colon content and/or faeces from individual pigs was determined. In all four countries the percentage resistance to ampicillin, streptomycin, sulphonamides or trimethoprim was significantly lower in E. coli from organic pigs. In France and Italy, the percentage of isolates resistant to chloramphenicol, ciprofloxacin, nalidixic acid or gentamicin was also significantly lower in the E. coli from organic pigs. Resistance to cefotaxime, was not found in any country. The percentage of E. coli isolates resistant to TET as well as the proportion of TET-resistant E. coli was significantly lower in organic than in conventional pigs, except in Sweden where TET-resistance was equally low in both production types. There were also differences between countries within production type in the percentage resistance to individual antibiotics as well as the proportion of TET-resistant E. coli with lower median proportions in Sweden and Denmark compared to France and Italy. The study shows that in each of the four countries resistance in intestinal E. coli was less common in organic than in conventional pigs, but that there were also large differences in resistance between countries within each production type, indicating that both country- and production-specific factors influence the occurrence of resistance.
Investigation of Biofield Treatment on Antimicrobial Susceptibility, Biochemical Reaction Pattern and Biotyping of Enteropathogenic Multidrug-Resistant Escherichia coli Isolates

OpenAIRE

Trivedi, Dahryn; Trivedi, Mahendra Kumar; Branton, Alice; Nayak, Gopal; Shettigar, Harish; Gangwar, Mayank; Jana, Snehasis

2015-01-01

Study background: Multidrug resistant Escherichia coli (MDR E. coli) has become a major health concern, and failure of treatment leads to huge health burden. Aim of the present study was to determine the impact of Mr. Trivedi’s biofield treatment on E. coli. Methods: Four MDR clinical lab isolates (LSs) of E. coli (LS 8, LS 9, LS 10, and LS 11) were taken and divided into two groups i.e. control and biofield treated. Control and treated samples were identified with respect to its antimicr...
Comparative genomics and transcriptomics of Escherichia coli isolates carrying virulence factors of both enteropathogenic and enterotoxigenic E. coli.

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Hazen, Tracy H; Michalski, Jane; Luo, Qingwei; Shetty, Amol C; Daugherty, Sean C; Fleckenstein, James M; Rasko, David A

2017-06-14

Escherichia coli that are capable of causing human disease are often classified into pathogenic variants (pathovars) based on their virulence gene content. However, disease-associated hybrid E. coli, containing unique combinations of multiple canonical virulence factors have also been described. Such was the case of the E. coli O104:H4 outbreak in 2011, which caused significant morbidity and mortality. Among the pathovars of diarrheagenic E. coli that cause significant human disease are the enteropathogenic E. coli (EPEC) and enterotoxigenic E. coli (ETEC). In the current study we use comparative genomics, transcriptomics, and functional studies to characterize isolates that contain virulence factors of both EPEC and ETEC. Based on phylogenomic analysis, these hybrid isolates are more genomically-related to EPEC, but appear to have acquired ETEC virulence genes. Global transcriptional analysis using RNA sequencing, demonstrated that the EPEC and ETEC virulence genes of these hybrid isolates were differentially-expressed under virulence-inducing laboratory conditions, similar to reference isolates. Immunoblot assays further verified that the virulence gene products were produced and that the T3SS effector EspB of EPEC, and heat-labile toxin of ETEC were secreted. These findings document the existence and virulence potential of an E. coli pathovar hybrid that blurs the distinction between E. coli pathovars.
Cemaran Escherichia coli pada Tepung Telur yang Diimpor Melalui Pelabuhan Tanjung Priok, dan Resistensinya Terhadap Antibiotik (ESCHERICHIA COLI CONTAMINATION ON EGG POWDER IMPORTED THROUGH PORT OF TANJUNG PRIOK AND ITS RESISTANCE AGAINST ANTIBIOTICS

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Kamil Riski Sidik

2016-07-01

Full Text Available Eschericia coli contamination was found on egg powder imported to Indonesia during microbialexamination. The study was conducted to describe the presence of E. coli and its resistance to antibioticsin egg powder imported to Indonesia through The port of Tanjung Priok. Samples was determined usingcross sectional study and the sample size was calculated based on assumption of confidence level of 95%with margin of error of 10% and predicted prevalence of 50%. Total of 100 egg powder samples wascollected in August 2014 from two exporting countries, Ukraine (whole egg powder, n=30 and India (wholeegg powder, n=40 and egg yolk powder, n=30. Examination was performed by packaging and label inspectionof the product followed by samples collection and testing for bacterial contamination using rapid test andconventional isolation and identification methods. Detected E. coli was isolated and then tested forantibiotic resistance. Examination results showed that 4 samples were positive to E. coli. E. coli isolatesshowed resistance against 6 types of antibiotics and 75% of the isolates had resistance against minimumof 3 types of antibiotics. These conditions should be taken into consideration since antibiotic resistance inE. coli would cause negative impacts on human, animal and environmental health.
Rapid and reliable discrimination between Shigella species and Escherichia coli using MALDI-TOF mass spectrometry.

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Paauw, Armand; Jonker, Debby; Roeselers, Guus; Heng, Jonathan M E; Mars-Groenendijk, Roos H; Trip, Hein; Molhoek, E Margo; Jansen, Hugo-Jan; van der Plas, Jan; de Jong, Ad L; Majchrzykiewicz-Koehorst, Joanna A; Speksnijder, Arjen G C L

2015-01-01

E. coli-Shigella species are a cryptic group of bacteria in which the Shigella species are distributed within the phylogenetic tree of E. coli. The nomenclature is historically based and the discrimination of these genera developed as a result of the epidemiological need to identify the cause of shigellosis, a severe disease caused by Shigella species. For these reasons, this incorrect classification of shigellae persists to date, and the ability to rapidly characterize E. coli and Shigella species remains highly desirable. Until recently, existing matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) assays used to identify bacteria could not discriminate between E. coli and Shigella species. Here we present a rapid classification method for the E. coli-Shigella phylogroup based on MALDI-TOF MS which is supported by genetic analysis. E. coli and Shigella isolates were collected and genetically characterized by MLVA. A custom reference library for MALDI-TOF MS that represents the genetic diversity of E. coli and Shigella strains was developed. Characterization of E. coli and Shigella species is based on an approach with Biotyper software. Using this reference library it was possible to distinguish between Shigella species and E. coli. Of the 180 isolates tested, 94.4% were correctly classified as E. coli or shigellae. The results of four (2.2%) isolates could not be interpreted and six (3.3%) isolates were classified incorrectly. The custom library extends the existing MALDI-TOF MS method for species determination by enabling rapid and accurate discrimination between Shigella species and E. coli. Copyright © 2015 Elsevier GmbH. All rights reserved.
Characterisation of STEC and other diarrheic E. coli isolated on CHROMagar™STEC at a tertiary referral hospital, Cape Town.

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Kalule, John Bosco; Keddy, Karen H; Nicol, Mark P

2018-06-08

Shiga toxin producing E. coli (STEC) is an emerging zoonotic pathogen that can cause acute renal failure, especially in children. Clinical microbiology laboratories may fail to detect STEC and other diarrhoeic E. coli unless purposive rigorous screening procedures are followed using appropriate diagnostic technology; CHROMagar™STEC has rarely been used for isolation of African diarrhoeic E. coli hence characteristics of isolates on this medium are not yet fully understood. This study aimed to determine the prevalence and characteristics of STEC and other diarrhoeic E. coli isolated on CHROMagar™STEC from stool samples submitted to the microbiology laboratory of a South African public sector tertiary care hospital. In total, 733 stool samples were tested. Of these, 4.5% (33/733) possessed diarrhoeic E. coli. Of the diarrheic E. coli, 5/33 (15.2%) were STEC, 15/33 (45.5%) EAggEC, 6/33 (18.2%) atypical EPEC, 5/33 (15.2%) typical EPEC, and 1/33 (3%) DAEC. None of the STEC isolates had been identified by routine testing (based on using sorbitol media to test for E. coli O157: H7 strains and not the other STEC) in the laboratory. Of the 33 strains, 55% (95% CI = 40.8-72.7) showed resistance to ampicillin. CHROMagar™STEC enabled detection of tellurite - resistant diarrhoeic E. coli that would be missed using routine methods. Further studies are needed to determine the proportion and characteristics of those which might have been missed using this approach.
Population structure of Cladophora-borne Escherichia coli in nearshore water of Lake Michigan.

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Byappanahalli, Muruleedhara N; Whitman, Richard L; Shively, Dawn A; Ferguson, John; Ishii, Satoshi; Sadowsky, Michael J

2007-08-01

We previously reported that the macrophytic green alga Cladophora harbors high densities (up to 10(6) colony-forming units/g dry weight) of the fecal indicator bacteria, Escherichia coli and enterococci, in shoreline waters of Lake Michigan. However, the population structure and genetic relatedness of Cladophora-borne indicator bacteria remain poorly understood. In this study, 835 E. coli isolates were collected from Cladophora tufts (mats) growing on rocks from a breakwater located within the Indiana Dunes National Lakeshore in northwest Indiana. The horizontal fluorophore enhanced rep-PCR (HFERP) DNA fingerprinting technique was used to determine the genetic relatedness of the isolates to each other and to those in a library of E. coli DNA fingerprints. While the E. coli isolates from Cladophora showed a high degree of genetic relatedness (92% similarity), in most cases, however, the isolates were genetically distinct. The Shannon diversity index for the population was very high (5.39). Both spatial and temporal influences contributed to the genetic diversity. There was a strong association of isolate genotypes by location (79% and 80% for lake- and ditch-side samplings, respectively), and isolates collected from 2002 were distinctly different from those obtained in 2003. Cladophora-borne E. coli isolates represented a unique group, which was distinct from other E. coli isolates in the DNA fingerprint library tested. Taken together, these results indicate that E. coli strains associated with Cladophora may be a recurring source of indicator bacteria to the nearshore beach.

Influence of controlled atmosphere on thermal inactivation of Escherichia coli ATCC 25922 in almond powder.

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Cheng, Teng; Li, Rui; Kou, Xiaoxi; Wang, Shaojin

2017-06-01

Heat controlled atmosphere (CA) treatments hold potential to pasteurize Salmonella enteritidis PT 30 in almonds. Nonpathogenic Escherichia coli ATCC 25922 was used as a surrogate species of pathogenic Salmonella for validation of thermal pasteurization to meet critical safety requirements. A controlled atmosphere/heating block system (CA-HBS) was used to rapidly determine thermal inactivation of E. coli ATCC 25922. D- and z-values of E. coli ATCC 25922 inoculated in almond powder were determined at four temperatures between 65 °C and 80 °C under different gas concentrations and heating rates. The results showed that D- and z-values of E. coli under CA treatment were significantly (P < 0.05) lower than those under regular atmosphere (RA) treatment at 4 given temperatures. Relatively higher CO 2 concentrations (20%) and lower O 2 concentrations (2%) were more effective to reduce thermal inactivation time. There were no significant differences in D-values of E. coli when heating rates were above 1 °C/min both in RA and CA treatments. But D-values significantly (P < 0.05) increased under RA treatment and decreased under CA treatment at lower heating rates. Combination of rapid heat and CA treatments could be a promising method for thermal inactivation of S. enteritidis PT 30 in almond powder. Copyright Â© 2017 Elsevier Ltd. All rights reserved.
Multidrug resistant commensal Escherichia coli in animals and its impact for public health

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Ama eSzmolka

2013-09-01

Full Text Available After the era of plentiful antibiotics we are alarmed by the increasing number of antibiotic resistant strains. The genetic flexibility and adaptability of E. coli to constantly changing environments allows to acquire a great number of antimicrobial resistance mechanisms. Commensal strains of E. coli as versatile residents of the lower intestine are also repeatedly challenged by antimicrobial pressures during the lifetime of their host. As a consequence, commensal strains acquire the respective resistance genes, and/or develop resistant mutants in order to survive and maintain microbial homeostasis in the lower intestinal tract. Thus, commensal E. coli strains are regarded as indicators of antimicrobial load on their hosts. This chapter provides a short historic background of the appearance and presumed origin and transfer of antimicrobial resistance genes in commensal intestinal E. coli of animals with comparative information on their pathogenic counterparts. The dynamics, development and ways of evolution of resistance in the E. coli populations differ according to hosts, resistance mechanisms and antimicrobial classes used. The most frequent tools of E. coli against a variety of antimicrobials are the efflux pumps and mobile resistance mechanisms carried by plasmids and/or other transferable elements. The emergence of hybrid plasmids (both resistance and virulence among E. coli is of further concern. Co-existence and co-transfer of these bad genes in this huge and most versatile in vivo compartment may represent an increased public health risk in the future. Significance of multidrug resistant (MDR commensal E. coli seem to be highest in the food animal industry, acting as reservoir for intra- and interspecific exchange and a source for spread of MDR determinants through contaminated food to humans. Thus, public health potential of MDR commensal E. coli of food animals can be a concern and needs monitoring and more molecular analysis in the
Neem (Azadirachta indica A. Juss Oil to Tackle Enteropathogenic Escherichia coli

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Paola Del Serrone

2015-01-01

Full Text Available Neem (Azadirachta indica A. Juss oil (NO was assayed against forty-eight isolates of Escherichia coli by standardised disc diffusion test and microdilution test. By molecular biology characterization, fourteen isolates resulted in diarrheagenic E. coli with sixteen primer pairs that specifically amplify unique sequences of virulence genes and of 16S rRNA. The NO showed biological activity against all isolates. The bacterial growth inhibition zone by disc diffusion method (100 µL NO ranged between 9.50 ± 0.70 and 30.00 ± 1.00 mm. The antibacterial activity was furthermore determined at lower NO concentrations (1 : 10–1 : 10,000. The percent of growth reduction ranged between 23.71 ± 1.00 and 99.70 ± 1.53. The highest bacterial growth reduction was 1 : 10 NO concentration with 50 µL of bacterial suspension (ca. 1 × 106 CFU/mL. There is significant difference between the antibacterial activities against pathogenic and nonpathogenic E. coli, as well as NO and ciprofloxacin activities. Viable cells after the different NO concentration treatments were checked by molecular biology assay using PMA dye. On the basis of the obtained results, NO counteracts E. coli and also influences the virulence of E. coli viable cells after NO treatment. The NO metabolomic composition was obtained using fingerprint HPTLC.
Hemolytic Porcine Intestinal Escherichia coli without Virulence-Associated Genes Typical of Intestinal Pathogenic E. coli ▿ †

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Schierack, Peter; Weinreich, Joerg; Ewers, Christa; Tachu, Babila; Nicholson, Bryon; Barth, Stefanie

2011-01-01

Testing 1,666 fecal or intestinal samples from healthy and diarrheic pigs, we obtained hemolytic Escherichia coli isolates from 593 samples. Focusing on hemolytic E. coli isolates without virulence-associated genes (VAGs) typical for enteropathogens, we found that such isolates carried a broad variety of VAGs typical for extraintestinal pathogenic E. coli. PMID:21965399
[Lactobacillus rhamnosus GG conditioned medium prevents E. coli meningitis by inhibiting nuclear factor-κB pathway].

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Zeng, Qing; He, Xiao-Long; Xiao, Han-Sheng; DU, Lei; Li, Yu-Jing; Chen, Le-Cheng; Tian, Hui-Wen; Huang, Sheng-He; Cao, Hong

2017-01-20

To investigate whether Lactobacillus rhamnosus GG conditioned medium(LGG-CM)has preventive effect against E. coli K1-induced neuropathogenicity in vitro by inhibiting nuclear factor-κB (NF-κB) signaling pathway. An in vitro blood-brain barrier (BBB) model was constructed using human brain microvascular endothelial cells (HBMECs). The effect of LGG-CM on E. coli-actived NF-κB signaling pathway was assayed using Western blotting. Invasion assay and polymorphonuclear leukocyte (PMN) transmigration assay were performed to explore whether LGG-CM could inhibit E. coli invasion and PMN transmigration across the BBB in vitro. The expressions of ZO-1 and CD44 were detected using Western blotting and immunofluorescence. The changes of trans-epithelial electric resistance (TEER) and bacterial translocation were determined to evaluate the BBB permeability. Pre-treament with LGG-CM inhibited E. coli-activated NF-κB signaling pathway in HBMECs and decreased the invasion of E. coli K1 and transmigration of PMN. Western blotting showed that LGG-CM could alleviate E. coli-induced up-regulation of CD44 and down-regulation of ZO-1 expressions in HBMECs. In addition, pre-treatment with LGG-CM alleviated E. coli K1-induced reduction of TEER and suppressed bacterial translocation across the BBB in vitro. LGG-CM can block E. coli-induced activation of NF-κB signaling pathway and thereby prevents E. coli K1-induced neuropathogenicity by decreasing E. coli K1 invasion rates and PMN transmigration.
ESBL-Producing Escherichia coli

DEFF Research Database (Denmark)

Hertz, Frederik Boetius

Urinary tract infection (UTI) is one the most common bacterial infections and is regularly treated in primary health care. The most common cause of UTI is extraintestinal pathogenic Escherichia coli (ExPEC) already present in the intestinal microflora, often as the dominating strain. Resistance...... in E.coli is increasing and especially isolates producing Extended-Spectrum Beta-Lactamases (ESBL) have been reported worldwide. Treatment of UTI is usually initiated by the general practitioners and a significant proportion of clinical isolates are now resistant to first line antibiotics. The global...... to investigate (i) antibiotics involved in selection of ESBL-producing E.coli, in an experimental mouse model in vivo, (ii) risk factors for UTI with ESBL-producing E.coli and (iii) to describe the phylogenetic composition of E.coli populations with different resistance patterns. We found that different...
Binding determinants in the interplay between porcine aminopeptidase N and enterotoxigenic Escherichia coli F4 fimbriae.

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Xia, Pengpeng; Quan, Guomei; Yang, Yi; Zhao, Jing; Wang, Yiting; Zhou, Mingxu; Hardwidge, Philip R; Zhu, Jianzhong; Liu, Siguo; Zhu, Guoqiang

2018-02-26

The binding of F4 + enterotoxigenic Escherichia coli (ETEC) and the specific receptor on porcine intestinal epithelial cells is the initial step in F4 + ETEC infection. Porcine aminopeptidase N (APN) is a newly discovered receptor for F4 fimbriae that binds directly to FaeG adhesin, which is the major subunit of the F4 fimbriae variants F4ab, F4ac, and F4ad. We used overlapping peptide assays to map the APN-FaeG binding sites, which has facilitated in the identifying the APN-binding amino acids that are located in the same region of FaeG variants, thereby limiting the major binding regions of APN to 13 peptides. To determine the core sequence motif, a panel of FaeG peptides with point mutations and FaeG mutants were constructed. Pull-down and binding reactivity assays using piglet intestines determined that the amino acids G159 of F4ab, N209 and L212 of F4ac, and A200 of F4ad were the critical residues for APN binding of FaeG. We further show using ELISA and confocal microscopy assay that amino acids 553-568, and 652-670 of the APN comprise the linear epitope for FaeG binding in all three F4 fimbriae variants.
Evaluation of Escherichia coli viability by flow cytometry: A method for determining bacterial responses to antibiotic exposure.

Science.gov (United States)

Boi, Paola; Manti, Anita; Pianetti, Anna; Sabatini, Luigia; Sisti, Davide; Rocchi, Marco Bruno; Bruscolini, Francesca; Galluzzi, Luca; Papa, Stefano

2015-01-01

In this study, we check for the presence of specific resistance genes by polymerase chain reaction (PCR) and then we used flow cytometry (FCM) to evaluate antibiotic-induced effects in different strains of Escherichia coli (E. coli). The presence of resistance genes was investigated by PCR in 10 strains of E. coli isolated from Foglia River. Bacterial responses to different antibiotics were also tested with FCM techniques by evaluating both the degree of decrease in viability and the light scatter changes in all of the strains. PCR revealed that only one strain exhibits the presence of one resistance gene. Despite this, analyses of strains using FCM evidenced the presence of viable subpopulations after antibiotic treatment. Furthermore, analyses of scatter signals revealed profound changes in the Forward Scatter and Side Scatter of the bacterial populations as a consequence of antibiotic exposure, confirming the viability and membrane potential data. The riverine strains were in general less sensitive to antibiotics than the reference strain (ATCC 25922). Antibiotic resistance is a widespread phenomena. The multiparametric approach based on FCM used in this study, providing results about different aspects (cell viability, membrane potential, light scatter changes), may overcome the limitation of PCR and could represent an adequate method for the evaluation of bacteria responses to antibiotic exposure. © 2014 International Clinical Cytometry Society.
Compilation and analysis of Escherichia coli promoter DNA sequences.

OpenAIRE

Hawley, D K; McClure, W R

1983-01-01

The DNA sequence of 168 promoter regions (-50 to +10) for Escherichia coli RNA polymerase were compiled. The complete listing was divided into two groups depending upon whether or not the promoter had been defined by genetic (promoter mutations) or biochemical (5' end determination) criteria. A consensus promoter sequence based on homologies among 112 well-defined promoters was determined that was in substantial agreement with previous compilations. In addition, we have tabulated 98 promoter ...
21 CFR 866.3255 - Escherichia coli serological reagents.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Escherichia coli serological reagents. 866.3255... coli serological reagents. (a) Identification. Escherichia coli serological reagents are devices that consist of antigens and antisera used in serological tests to identify Escherichia coli from cultured...
The impact of fecal sample processing on prevalence estimates for antibiotic-resistant Escherichia coli.

Science.gov (United States)

Omulo, Sylvia; Lofgren, Eric T; Mugoh, Maina; Alando, Moshe; Obiya, Joshua; Kipyegon, Korir; Kikwai, Gilbert; Gumbi, Wilson; Kariuki, Samuel; Call, Douglas R

2017-05-01

Investigators often rely on studies of Escherichia coli to characterize the burden of antibiotic resistance in a clinical or community setting. To determine if prevalence estimates for antibiotic resistance are sensitive to sample handling and interpretive criteria, we collected presumptive E. coli isolates (24 or 95 per stool sample) from a community in an urban informal settlement in Kenya. Isolates were tested for susceptibility to nine antibiotics using agar breakpoint assays and results were analyzed using generalized linear mixed models. We observed a 0.1). Prevalence estimates did not differ for five distinct E. coli colony morphologies on MacConkey agar plates (P>0.2). Successive re-plating of samples for up to five consecutive days had little to no impact on prevalence estimates. Finally, culturing E. coli under different conditions (with 5% CO 2 or micro-aerobic) did not affect estimates of prevalence. For the conditions tested in these experiments, minor modifications in sample processing protocols are unlikely to bias estimates of the prevalence of antibiotic-resistance for fecal E. coli. Copyright © 2017 Elsevier B.V. All rights reserved.
Asymptomatic bacteriuria Escherichia coli strains

DEFF Research Database (Denmark)

Hancock, Viktoria; Nielsen, E.M.; Klemm, Per

2006-01-01

Urinary tract infections (UTIs) affect millions of people each year. Escherichia coli is the most common organism associated with asymptomatic bacteriuria (ABU) in humans. Persons affected by ABU may carry a particular E. coli strain for extended periods of time without any symptoms. In contrast...... to uropathogenic E. coli (UPEC) that cause symptomatic UTI, very little is known about the mechanisms by which these strains colonize the urinary tract. Here, we have investigated the growth characteristics in human urine as well as adhesin repertoire of nine ABU strains; the ability of ABU strains to compete...
Detection and Classification of Live and Dead Escherichia coli by Laser-Induced Breakdown Spectroscopy

Science.gov (United States)

Sivakumar, P.; Fernández-Bravo, A.; Taleh, L.; Biddle, J.F.

2015-01-01

Abstract A common goal for astrobiology is to detect organic materials that may indicate the presence of life. However, organic materials alone may not be representative of currently living systems. Thus, it would be valuable to have a method with which to determine the health of living materials. Here, we present progress toward this goal by reporting on the application of laser-induced breakdown spectroscopy (LIBS) to study characteristics of live and dead cells using Escherichia coli (E. coli) strain K12 cells as a model organism since its growth and death in the laboratory are well understood. Our goal is to determine whether LIBS, in its femto- and/or nanosecond forms, could ascertain the state of a living organism. E. coli strain K12 cells were grown, collected, and exposed to one of two types of inactivation treatments: autoclaving and sonication. Cells were also kept alive as a control. We found that LIBS yields key information that allows for the discrimination of live and dead E. coli bacteria based on ionic shifts reflective of cell membrane integrity. Key Words: E. coli—Trace elements—Live and dead cells—Laser-induced breakdown spectroscopy—Atomic force microscopy. Astrobiology 15, 144–153. PMID:25683088
Impact of enumeration method on diversity of Escherichia coli genotypes isolated from surface water.

Science.gov (United States)

Martin, E C; Gentry, T J

2016-11-01

There are numerous regulatory-approved Escherichia coli enumeration methods, but it is not known whether differences in media composition and incubation conditions impact the diversity of E. coli populations detected by these methods. A study was conducted to determine if three standard water quality assessments, Colilert ® , USEPA Method 1603, (modified mTEC) and USEPA Method 1604 (MI), detect different populations of E. coli. Samples were collected from six watersheds and analysed using the three enumeration approaches followed by E. coli isolation and genotyping. Results indicated that the three methods generally produced similar enumeration data across the sites, although there were some differences on a site-by-site basis. The Colilert ® method consistently generated the least diverse collection of E. coli genotypes as compared to modified mTEC and MI, with those two methods being roughly equal to each other. Although the three media assessed in this study were designed to enumerate E. coli, the differences in the media composition, incubation temperature, and growth platform appear to have a strong selective influence on the populations of E. coli isolated. This study suggests that standardized methods of enumeration and isolation may be warranted if researchers intend to obtain individual E. coli isolates for further characterization. This study characterized the impact of three USEPA-approved Escherichia coli enumeration methods on observed E. coli population diversity in surface water samples. Results indicated that these methods produced similar E. coli enumeration data but were more variable in the diversity of E. coli genotypes observed. Although the three methods enumerate the same species, differences in media composition, growth platform, and incubation temperature likely contribute to the selection of different cultivable populations of E. coli, and thus caution should be used when implementing these methods interchangeably for
High dietary zinc feeding promotes persistence of multi-resistant E. coli in the swine gut.

Science.gov (United States)

Ciesinski, Lisa; Guenther, Sebastian; Pieper, Robert; Kalisch, Martin; Bednorz, Carmen; Wieler, Lothar H

2018-01-01

High levels of zinc oxide are used frequently as feed additive in pigs to improve gut health and growth performance and are still suggested as an alternative to antimicrobial growth promoters. However, we have recently described an increase of multi-resistant E. coli in association to zinc feeding in piglets. This previous study focused on clonal diversity of E. coli, observing the effect on multi-resistant strains by chance. To shed further light into this highly important topic and falsify our previous findings, we performed a zinc pig feeding trial where we specifically focused on in-depth analysis of antimicrobial resistant E. coli. Under controlled experimental conditions, piglets were randomly allocated to a high dietary zinc (zinc group) and a background zinc feeding group (control group). At different ages samples were taken from feces, digesta, and mucosa and absolute E. coli numbers were determined. A total of 2665 E. coli isolates were than phenotypically tested for antimicrobial resistance and results were confirmed by minimum inhibitory concentration testing for random samples. In piglets fed with high dietary zinc, we detected a substantial increase of multi-resistant E. coli in all gut habitats tested, ranging from 28.9-30.2% multi-resistant E. coli compared to 5.8-14.0% in the control group. This increase was independent of the total number of E. coli. Interestingly, the total amount of the E. coli population decreased over time. Thus, the increase of the multi-resistant E. coli populations seems to be linked with persistence of the resistant population, caused by the influence of high dietary zinc feeding. In conclusion, these findings corroborate our previous report linking high dietary zinc feeding of piglets with the occurrence of antimicrobial resistant E. coli and therefore question the feeding of high dietary zinc oxide as alternative to antimicrobial growth promoters.
Synergistic effect of enterocin AS-48 in combination with outer membrane permeabilizing treatments against Escherichia coli O157:H7.

Science.gov (United States)

Ananou, S; Gálvez, A; Martínez-Bueno, M; Maqueda, M; Valdivia, E

2005-01-01

To determine the effects of outer membrane (OM) permeabilizing agents on the antimicrobial activity of enterocin AS-48 against Escherichia coli O157:H7 CECT 4783 strain in buffer and apple juice. We determined the influence of pH, EDTA, sodium tripolyphosphate (STPP) and heat on E. coli O157:H7 CECT 4783 sensitivity to enterocin AS-48 in buffer and in apple juice. Enterocin AS-48 was not active against intact cells of E. coli O157:H7 CECT 4783 at neutral pH. However, cells sublethally injured by OM permeabilizing agents (EDTA, STPP, pH 5, pH 8.6 and heat) became sensitive to AS-48, decreasing the amount of bacteriocin required for inhibition of E. coli O157:H7 CECT 4783. The results presented indicate that enterocin AS-48 could potentially be applied with a considerably wider range of protective agents, such as OM permeabilizing agents, with increased efficacy in inhibiting E. coli O157:H7. Results from this study support the potential use of enterocin AS-48 to control E. coli O157:H7 in combination with other hurdles.
Comparative Genomics of Escherichia coli Strains Causing Urinary Tract Infections

DEFF Research Database (Denmark)

Vejborg, Rebecca Munk; Hancock, Viktoria; Schembri, Mark A.

2011-01-01

The virulence determinants of uropathogenic Escherichia coli have been studied extensively over the years, but relatively little is known about what differentiates isolates causing various types of urinary tract infections. In this study, we compared the genomic profiles of 45 strains from a range...
Impedimetric test for rapid determination of performic acid (PFA) biocidal activity toward Echerichia coli

OpenAIRE

Małgorzata Lasik; Renata Dobrucka; Piotr Konieczny

2013-01-01

Background. Performic acid has recently become available on a commercial scale for potential use in waste-water disinfection and can become an innovative biocide for various purposes in food processing. The aim of our study was: 1) to investigate the antimicrobial resistance of performic acid as high active and non toxic chemical disinfectant against Escherichi coli (hygiene indicator test microorganism used in industrial micro- biology) and 2) to evaluate the electrical impedanc...
Escherichia coli EDL933 Requires Gluconeogenic Nutrients To Successfully Colonize the Intestines of Streptomycin-Treated Mice Precolonized with E. coli Nissle 1917

Science.gov (United States)

Schinner, Silvia A. C.; Mokszycki, Matthew E.; Adediran, Jimmy; Leatham-Jensen, Mary; Conway, Tyrrell

2015-01-01

Escherichia coli MG1655, a K-12 strain, uses glycolytic nutrients exclusively to colonize the intestines of streptomycin-treated mice when it is the only E. coli strain present or when it is confronted with E. coli EDL933, an O157:H7 strain. In contrast, E. coli EDL933 uses glycolytic nutrients exclusively when it is the only E. coli strain in the intestine but switches in part to gluconeogenic nutrients when it colonizes mice precolonized with E. coli MG1655 (R. L. Miranda et al., Infect Immun 72:1666–1676, 2004, http://dx.doi.org/10.1128/IAI.72.3.1666-1676.2004). Recently, J. W. Njoroge et al. (mBio 3:e00280-12, 2012, http://dx.doi.org/10.1128/mBio.00280-12) reported that E. coli 86-24, an O157:H7 strain, activates the expression of virulence genes under gluconeogenic conditions, suggesting that colonization of the intestine with a probiotic E. coli strain that outcompetes O157:H7 strains for gluconeogenic nutrients could render them nonpathogenic. Here we report that E. coli Nissle 1917, a probiotic strain, uses both glycolytic and gluconeogenic nutrients to colonize the mouse intestine between 1 and 5 days postfeeding, appears to stop using gluconeogenic nutrients thereafter in a large, long-term colonization niche, but continues to use them in a smaller niche to compete with invading E. coli EDL933. Evidence is also presented suggesting that invading E. coli EDL933 uses both glycolytic and gluconeogenic nutrients and needs the ability to perform gluconeogenesis in order to colonize mice precolonized with E. coli Nissle 1917. The data presented here therefore rule out the possibility that E. coli Nissle 1917 can starve the O157:H7 E. coli strain EDL933 of gluconeogenic nutrients, even though E. coli Nissle 1917 uses such nutrients to compete with E. coli EDL933 in the mouse intestine. PMID:25733524
Escherichia coli at Ohio Bathing Beaches--Distribution, Sources, Wastewater Indicators, and Predictive Modeling

Science.gov (United States)

Francy, Donna S.; Gifford, Amie M.; Darner, Robert A.

2003-01-01

Results of studies during the recreational seasons of 2000 and 2001 strengthen the science that supports monitoring of our Nation?s beaches. Water and sediment samples were collected and analyzed for concentrations of Escherichia coli (E. coli). Ancillary water-quality and environmental data were collected or compiled to determine their relation to E. coli concentrations. Data were collected at three Lake Erie urban beaches (Edgewater, Villa Angela, and Huntington), two Lake Erie beaches in a less populated area (Mentor Headlands and Fairport Harbor), and one inland-lake beach (Mosquito Lake). The distribution of E. coli in water and sediments within the bathing area, outside the bathing area, and near the swash zone was investigated at the three Lake Erie urban beaches and at Mosquito Lake. (The swash zone is the zone that is alternately covered and exposed by waves.) Lake-bottom sediments from outside the bathing area were not significant deposition areas for E. coli. In contrast, interstitial water and subsurface sediments from near the swash zone were enriched with E. coli. For example, E. coli concentrations were as high as 100,000 colonies per 100 milliliters in some interstitial waters. Although there are no standards for E. coli in swash-zone materials, the high concentrations found at some locations warrant concern for public health. Studies were done at Mosquito Lake to identify sources of fecal contamination to the lake and bathing beach. Escherichia coli concentrations decreased with distance from a suspected source of fecal contamination that is north of the beach but increased at the bathing beach. This evidence indicated that elevated E. coli concentrations at the bathing beach are of local origin rather than from transport of bacteria from sites to the north. Samples collected from the three Lake Erie urban beaches and Mosquito Lake were analyzed to determine whether wastewater indicators could be used as surrogates for E. coli at bathing beaches

Escherichia coli as bioindicator of the groundwater quality in Palmerah District, West Jakarta, Indonesia

Science.gov (United States)

Dayanti, M. P.; Fachrul, M. F.; Wijayanti, A.

2018-01-01

The aim of thie research is to determine the quality of groundwater in Palmerah District, West Jakarta (6°11’24.32”S 106°47’49.88”E) by correlation between the depth of the well and the distance of septic tank with the distribution of Escherichia coli. The presence of E. coli is measured by using the Most Probable Number method. The distribution pattern of the E. coli was processed by Surfer Program. Research was conducted in April upto July 2017. The highest amount of E. coli always found in the Jati Pulo and Palmerah sub-district which is >1100 MPN/100 ml; while the lowest amount of E. coli found in the Kemanggisan sub-district and Slipi sub-district which is <3.0 MPN/100 ml; with every samples is obtained on the condition of pH 5 - 7, DO 0.81 - 7.65, and water temperature of 26 - 34°C. Refering to the Ministry of Health Regulation No. 492 of 2010 on the requirements of drinking water quality; it is shown that the groundwater in Palmerah District is not feasible to be directly consumed. This research provides the initial information to local sanitation to the distribution pattern of E. coli within the dense residential area.
Toxicity of granular activated carbon treated coal gasification water as determined by the Microtox test and Escherichia coli.

Science.gov (United States)

Makino, Y; Adams, J C; McTernan, W F

1986-01-01

The Microtox assay and various parameters (growth, ATP concentration and electrochemical detection) of Escherichia coli were used to assess the toxicity of various levels of granular activated carbon treated coal gasification process water. The generation time of E. coli was statistically significantly slower at the level of 50 percent treatment than any other level of treatment. No differences were seen for ATP concentration per cell or in the electrochemical detection methods for any level treatment. There was a very high correlation between total organic carbon removal by GAC treatment and reduction in toxicity as measured by the Microtox system. However, even the treated water which had 91 percent of the TOC removed was still highly toxic.
Ciprofloxacin-resistant Escherichia coli in Central Greece: mechanisms of resistance and molecular identification

Directory of Open Access Journals (Sweden)

Mavroidi Angeliki

2012-12-01

Full Text Available Abstract Background Fluoroquinolone resistant E. coli isolates, that are also resistant to other classes of antibiotics, is a significant challenge to antibiotic treatment and infection control policies. In Central Greece a significant increase of ciprofloxacin-resistant Escherichia coli has occurred during 2011, indicating the need for further analysis. Methods A total of 106 ciprofloxacin-resistant out of 505 E. coli isolates consecutively collected during an eight months period in a tertiary Greek hospital of Central Greece were studied. Antimicrobial susceptibility patterns and mechanisms of resistance to quinolones were assessed, whereas selected isolates were further characterized by multilocus sequence typing and β-lactamase content. Results Sequence analysis of the quinolone-resistance determining region of the gyrA and parC genes has revealed that 63% of the ciprofloxacin-resistant E. coli harbored a distinct amino acid substitution pattern (GyrA:S83L + D87N; ParC:S80I + E84V, while 34% and 3% carried the patterns GyrA:S83L + D87N; ParC:S80I and GyrA:S83L + D87N; ParC:S80I + E84G respectively. The aac (6’-1b-cr plasmid-mediated quinolone resistance determinant was also detected; none of the isolates was found to carry the qnrA, qnrB and qnrS. Genotyping of a subset of 35 selected ciprofloxacin-resistant E. coli by multilocus sequence typing has revealed the presence of nine sequence types; ST131 and ST410 were the most prevalent and were exclusively correlated with hospital and health care associated infections, while strains belonging to STs 393, 361 and 162 were associated with community acquired infections. The GyrA:S83L + D87N; ParC:S80I + E84V substitution pattern was found exclusively among ST131 ciprofloxacin-resistant E. coli. Extended-spectrum β-lactamase-positive ST131 ciprofloxacin-resistant isolates produced CTX-M-type enzymes; eight the CTX-M-15 and one the CTX-M-3 variant. CTX-M-1 like and KPC-2 enzymes were detected
Shiga toxin-converting phages and the emergence of new pathogenic Escherichia coli: a world in motion

Science.gov (United States)

Tozzoli, Rosangela; Grande, Laura; Michelacci, Valeria; Ranieri, Paola; Maugliani, Antonella; Caprioli, Alfredo; Morabito, Stefano

2014-01-01

Shiga toxin (Stx)-producing Escherichia coli (STEC) are pathogenic E. coli causing diarrhea, hemorrhagic colitis (HC) and hemolytic uremic syndrome (HUS). STEC are characterized by a constellation of virulence factors additional to Stx and have long been regarded as capable to cause HC and HUS when possessing the ability of inducing the attaching and effacing (A/E) lesion to the enterocyte, although strains isolated from such severe infections sometimes lack this virulence feature. Interestingly, the capability to cause the A/E lesion is shared with another E. coli pathogroup, the Enteropathogenic E. coli (EPEC). In the very recent times, a different type of STEC broke the scene causing a shift in the paradigm for HUS-associated STEC. In 2011, a STEC O104:H4 caused a large outbreak with more than 800 HUS and 50 deaths. Such a strain presented the adhesion determinants of Enteroaggregative E. coli (EAggEC). We investigated the possibility that, besides STEC and EAggEC, other pathogenic E. coli could be susceptible to infection with stx-phages. A panel of stx2-phages obtained from STEC isolated from human disease was used to infect experimentally E. coli strains representing all the known pathogenic types, including both diarrheagenic E. coli (DEC) and extra-intestinal pathogenic E. coli (ExPEC). We observed that all the E. coli pathogroups used in the infection experiments were susceptible to the infection. Our results suggest that the stx2-phages used may not have specificity for E. coli adapted to the intestinal environment, at least in the conditions used. Additionally, we could only observe transient lysogens suggesting that the event of stable stx2-phage acquisition occurs rarely. PMID:24999453
Ribosome slowed by mutation to streptomycin resistance. [Escherichia coli

Energy Technology Data Exchange (ETDEWEB)

Galas, D J; Branscomb, E W

1976-08-12

The effect of mutation to streptomycin resistance on the speed of polypeptide elongation in Escherichia coli was investigated. Translation speed was determined by measuring the time required for the first newly synthesized ..beta..-galactosidase molecules to appear after induction of the lactose operon. The results showed that ribosome speed is not a fixed parameter inherent to the protein synthetic apparatus, but a variable determined by the kinetics of translation and ultimately by the structure of the ribosome. (HLW)
Inhibitory effect of 2‑mercaptoethane sulfonate on the formation of Escherichia coli biofilms in vitro.

Science.gov (United States)

Chen, Sheng; He, Nianhai; Yu, Jialin; Li, Luquan; Sun, Fengjun; Hu, Ying; Deng, Rui; Zhong, Shiming; Shen, Leilei

2015-10-01

The biofilms (BF) formed by Escherichia coli (E. coli) is an important cause of chronic and recurrent infections due to its capacity to persist on medical surfaces and indwelling devices, demonstrating the importance of inhibiting the formation of E. coli BF and reducing BF infection. Although 2‑mercaptoethane sulfonate (MESNA) exhibits a marked mucolytic effect clinically, the effect of MESNA on the inhibition of E. coli BF formation remains to be elucidated. The present study investigated whether MESNA inhibits the formation of E. coli BF in vitro. The minimum inhibitory concentration of MESNA on E. coli was determined to be 10 mg/ml. Subsequently, the effect of MESNA on BF early adhesion, extracellular polysaccharide (EPS) and extracellular protein were detected. The effect of a subinhibitory concentration of MESNA on BF formation was evaluated, and the inhibitory potency of MESNA against matured BF was assayed. The results revealed that MESNA inhibited early stage adhesion and formation of the E. coli BF, destroyed the mature BF membrane and reduced the EPS and extracellular proteins levels of the BF. In addition, the present study investigated the effects of MESNA on the expression of EPS‑ and adhesion protein‑associated genes using quantitative polymerase chain reaction analysis, which demonstrated that MESNA effectively inhibited the expression of these genes. These results suggested that MESNA possesses anti‑BF formation capability on E. coli in vitro and may be used as a potential reagent for the clinical treatment of E. coli BF‑associated infections.
DNA supercoiling depends on the phosphorylation potential in Escherichia coli

DEFF Research Database (Denmark)

Van Workum, M.; van Dooren, S.J.M; Oldenburg, N

1996-01-01

ATP/ADP ratios were varied in different ways and the degree of negative supercoiling was determined in Escherichia coli. Independent of whether the ATP/ADP ratio was reduced by a shift to anaerobic conditions, by addition of protonophore (dinitrophenol) or by potassium cyanide addition, DNA super...
Assessments of Total and Viable Escherichia coli O157:H7 on Field and Laboratory Grown Lettuce

Science.gov (United States)

Moyne, Anne-Laure; Harris, Linda J.; Marco, Maria L.

2013-01-01

Leafy green produce has been associated with numerous outbreaks of foodborne illness caused by strains of Escherichia coli O157:H7. While the amounts of culturable E. coli O157:H7 rapidly decline after introduction onto lettuce in the field, it remains to be determined whether the reduction in cell numbers is due to losses in cell viability, cell injury and a subsequent inability to be detected by standard laboratory culturing methods, or a lack of adherence and hence rapid removal of the organism from the plants during application. To assess which of these options is most relevant for E. coli O157:H7 on leafy green produce, we developed and applied a propidium monoazide (PMA) real-time PCR assay to quantify viable (with PMA) and total (without PMA) E. coli O157:H7 cells on growth chamber and field-grown lettuce. E. coli O157:H7, suspended in 0.1% peptone, was inoculated onto 4-week-old lettuce plants at a level of approximately 106 CFU/plant. In the growth chamber at low relative humidity (30%), culturable amounts of the nontoxigenic E. coli O157:H7 strain ATCC 700728 and the virulent strain EC4045 declined 100 to 1000-fold in 24 h. Fewer E. coli O157:H7 cells survived when applied onto plants in droplets with a pipette compared with a fine spray inoculation. Total cells for both strains were equivalent to inoculum levels for 7 days after application, and viable cell quantities determined by PMA real-time PCR were approximately 104 greater than found by colony enumeration. Within 2 h after application onto plants in the field, the number of culturable E. coli ATCC 700728 was reduced by up to 1000-fold, whereas PCR-based assessments showed that total cell amounts were equivalent to inoculum levels. These findings show that shortly after inoculation onto plants, the majority of E. coli O157:H7 cells either die or are no longer culturable. PMID:23936235
Clorate Metabolism in Pure Cultures of E.Coli 0157:H7 Pretreated with Either Nitrate or Chlorate

Science.gov (United States)

Experiments were conducted to determine the effects of 5, 7.5, and 10 mM nitrate, and 5, 10, or 20 mM chlorate on total E. coli counts, chlorate metabolism, and volatile fatty acid (VFA) concentrations in anaerobic ruminal fluid cultures. Nitrate did not affect total E. coli counts (P = 0.05), chlor...
ANTIBACTERIAL ACTIVITY OF DRACONTOMELON DAO EXTRACTS ON METHICILLIN-RESISTANT S. AUREUS (MRSA) AND E. COLI MULTIPLE DRUG RESISTANCE (MDR).

Science.gov (United States)

Yuniati, Yuniati; Hasanah, Nurul; Ismail, Sjarif; Anitasari, Silvia; Paramita, Swandari

2018-01-01

Staphylococcus aureus , methicillin-resistant and Escherichia coli , multidrug-resistant included in the list of antibiotic-resistant priority pathogens from WHO. As multidrug-resistant bacteria problem is increasing, it is necessary to probe new sources for identifying antimicrobial compounds. Medicinal plants represent a rich source of antimicrobial agents. One of the potential plants for further examined as antibacterial is Dracontomelon dao (Blanco) Merr. & Rolfe. The present study designed to find the antibacterial activity of D. dao stem bark extracts on Methicillin-resistant S. aureus (MRSA) and E. coli Multiple Drug Resistance (MDR), followed by determined secondary metabolites with antibacterial activity and determined the value of MIC (minimum inhibitory concentration) and MBC (minimum bactericidal concentration). D. dao stem bark extracted using 60% ethanol. Disc diffusion test methods used to find the antibacterial activity, following by microdilution methods to find the value of MIC and MBC. Secondary metabolites with antibacterial activity determined by bioautography using TLC (thin layer chromatography) methods. D. dao stem bark extracts are sensitive to MSSA, MRSA and E.coli MDR bacteria. The inhibition zone is 16.0 mm in MSSA, 11.7 mm in MRSA and 10.7 mm in E. coli MDR. The entire MBC/MIC ratios for MSSA, MRSA and E.coli MDR is lower than 4. The ratio showed bactericidal effects of D. dao stem bark extracts. In TLC results, colorless bands found to be secondary metabolites with antibacterial activity. D. dao stem bark extracts are potential to develop as antibacterial agent especially against MRSA and E. coli MDR strain.
Evaluation of immunological methods for detection of bovine growth hormone (BGH) produced in E. coli

International Nuclear Information System (INIS)

Rosner, A.; Zwang, R.; Aviv, H.

1982-01-01

The use of several immunological methods for studies on synthesis of bovine growth hormone (BGH) by E. coli is described here. The ELISA procedure was shown to be the least sensitive and unfit for assaying BGH in E. coli extracts. The solid-phase radioimmunoassay (RIA) proved to be highly sensitive, but since E. coli extract itself (not containing BGH) interfered with the immunological reaction, its use for measuring BGH was practically limited. The best adequate procedure proved to be radioimmunoassay in solution, which was not adversely affected by the E. coli extract and was sufficiently sensitive to detect nanogram quantities of BGH. The size of the BGH produced by normal bacterial cells was investigated by protein fractionation, transfer to nitrocellulose paper and detection by anti-BGH serum. This method also served for semi-quantitative determination of BGH in the bacterial extract. (Auth.)
Evaluation of immunological methods for detection of bovine growth hormone (BGH) produced in E. coli

Energy Technology Data Exchange (ETDEWEB)

Rosner, A; Zwang, R; Aviv, H [Weizmann Institute of Science, Rehovot (Israel). Dept. of Virology

1982-07-30

The use of several immunological methods for studies on synthesis of bovine growth hormone (BGH) by E. coli is described here. The ELISA procedure was shown to be the least sensitive and unfit for assaying BGH in E. coli extracts. The solid-phase radioimmunoassay (RIA) proved to be highly sensitive, but since E. coli extract itself (not containing BGH) interfered with the immunological reaction, its use for measuring BGH was practically limited. The most adequate procedure proved to be radioimmunoassay in solution, which was not adversely affected by the E. coli extract and was sufficiently sensitive to detect nanogram quantities of BGH. The size of the BGH produced by normal bacterial cells was investigated by protein fractionation, transfer to nitrocellulose paper and detection by anti-BGH serum. This method also served for semi-quantitative determination of BGH in the bacterial extract.
Characterization of ESBL-producing Escherichia coli and Klebsiella pneumoniae strains isolated from urine of nonhospitalized patients in the Zagreb region

Directory of Open Access Journals (Sweden)

Branka Bedenić,

2010-02-01

Full Text Available Aim To determine the prevalence of ESBL-producing Escherichia coli and Klebsiella pneumoniae strains isolated from urine of nonhospitalized patients during a three-year period, to determine their antibiotic susceptibility, investigate the transfer of ESBL genes with cotransfer of resistance and to characterize isolated beta-lactamases. Methods Antimicrobial susceptibility was determined by disk diffusion and broth microdilution methods. The double-disk test was used for ESBL detection. Transfer of resistance was performed by broth mating method and characterization of isolated beta-lactamases by polymerase chain reaction. Results The prevalence of ESBL-producing E. coli was 1.5% and of K. pneumoniae 4.1% with its different distribution according to patients`age and gender. ESBL-producing K. pneumoniae showed high resistance rates to aminoglycosides, cotrimoxazole, nitrofurantoin and quinolones while ESBL-producing E. coli isolates, with exception of high aminoglycoside resistance, showed low resistance rates to other antibiotics. Successful conjugation of ESBL genes was obtained with 25% E. coli and 76.2% K. pneumoniae strains. Comparing to E. coli, K. pneumoniae strains showed higher rates of aminoglycosideand cotrimoxazole resistance cotransfer. Beta-lactamases of investigated strains belonged to TEM, SHV and CTX-M families.Conclusion The existence of multiple-resistant ESBL-producing E. coli and K. pneumoniae strains was confirmed in observed outpatient population. ESBL-producing K. pneumoniae isolates, in contrast toESBL-producing E. coli, showed higher resistance rates to non-beta-lactam antibiotics, probably caused by cotransfer of resistance genes located on the same plasmid as ESBL genes. It is important to monitor the prevalence of such strains and their possible spreading in the outpatient population of the Zagreb region
Evolved Escherichia coli Strains for Amplified, Functional Expression of Membrane Proteins

NARCIS (Netherlands)

Gul, Nadia; Linares, Daniel M.; Ho, Franz Y.; Poolman, Bert

2014-01-01

The major barrier to the physical characterization and structure determination of membrane proteins is low protein yield and/or low functionality in recombinant expression. The enteric bacterium Escherichia coli is the most widely employed organism for producing recombinant proteins. Beside several
Most probable number methodology for quantifying dilute concentrations and fluxes of Escherichia coli O157:H7 in surface waters.

Science.gov (United States)

Jenkins, M B; Endale, D M; Fisher, D S; Gay, P A

2009-02-01

To better understand the transport and enumeration of dilute densities of Escherichia coli O157:H7 in agricultural watersheds, we developed a culture-based, five tube-multiple dilution most probable number (MPN) method. The MPN method combined a filtration technique for large volumes of surface water with standard selective media, biochemical and immunological tests, and a TaqMan confirmation step. This method determined E. coli O157:H7 concentrations as low as 0.1 MPN per litre, with a 95% confidence level of 0.01-0.7 MPN per litre. Escherichia coli O157:H7 densities ranged from not detectable to 9 MPN per litre for pond inflow, from not detectable to 0.9 MPN per litre for pond outflow and from not detectable to 8.3 MPN per litre for within pond. The MPN methodology was extended to mass flux determinations. Fluxes of E. coli O157:H7 ranged from 10(4) MPN per hour. This culture-based method can detect small numbers of viable/culturable E. coli O157:H7 in surface waters of watersheds containing animal agriculture and wildlife. This MPN method will improve our understanding of the transport and fate of E. coli O157:H7 in agricultural watersheds, and can be the basis of collections of environmental E. coli O157:H7.
Multiplex PCR Assay for Identification of Human Diarrheagenic Escherichia coli

OpenAIRE

Toma, Claudia; Lu, Yan; Higa, Naomi; Nakasone, Noboru; Chinen, Isabel; Baschkier, Ariela; Rivas, Marta; Iwanaga, Masaaki

2003-01-01

A multiplex PCR assay for the identification of human diarrheagenic Escherichia coli was developed. The targets selected for each category were eae for enteropathogenic E. coli, stx for Shiga toxin-producing E. coli, elt and est for enterotoxigenic E. coli, ipaH for enteroinvasive E. coli, and aggR for enteroaggregative E. coli. This assay allowed the categorization of a diarrheagenic E. coli strain in a single reaction tube.
Characterization of diarrhoeagenic Escherichia coli isolates in Jordanian children.

Science.gov (United States)

Shehabi, Asem A; Bulos, Najawa-Kuri; Hajjaj, Kamal G

2003-01-01

In a prospective study carried out among Jordanian children in Amman, a total of 73/250 (29.2%) stool specimens were positive for 1 or more diarrhoeagenic Escherichia coli strains using a multiplex polymerase chain reaction method. This study indicated that diarrhoeagenic E. coli isolates were found frequently more in stools of children with diarrhoea (34%) than without diarrhoea (23.1%), but without any significant difference (p > 0.05). The predominant diarrhoeagenic E. coli strains associated with diarrhoea were enteropathogenic E. coli (11.3%), followed by enterotoxigenic E. coli (9.8%) and enteroaggrative E. coli (9%), whereas in the control group these were 4.3%, 11.1% and 6%, respectively. Enteroinvasive E. coli strains (2.9%) were found only in stools of children with diarrhoea. This study revealed the absence of enterohaemorrhagic E. coli in both diarrhoeal and control stools, and found that diarrhoeagenic E. coli isolates were highly resistance to tetracycline (55%), co-trimoxazole (60%) and ampicillin (89%), which are commonly used antibiotics in Jordan.
Rapid determination of antibiotic resistance in E. coli using dielectrophoresis

International Nuclear Information System (INIS)

Hoettges, Kai F; Dale, Jeremy W; Hughes, Michael P

2007-01-01

In recent years, infections due to antibiotic-resistant strains of bacteria such as methillicin-resistant Staphylococcus aureus and ciprofloxacin-resistant Escherichia coli are on the rise, and with them the demand for rapid antibiotic testing is also rising. Conventional tests, such as disc diffusion testing, require a primary sample to be tested in the presence of a number of antibiotics to verify which antibiotics suppress growth, which take approximately 24 h to complete and potentially place the patient at severe risk. In this paper we describe the use of dielectrophoresis as a rapid marker of cell death, by detecting changes in the electrophysiology of the cell caused by the administration of an antibiotic. In contrast to other markers, the electrophysiology of the cell changes rapidly during cell death allowing live cells to be distinguished from dead (or dying) cells without the need for culturing. Using polymyxin B as an example antibiotic, our studies indicate that significant changes in cell characteristics can be observed as soon as 1 h passes after isolating a culture from nutrient broth
An Effect of Cadmium and Lead Ions on Escherichia coli with the Cloned Gene for Metallothionein (MT-3) Revealed by Electrochemistry

International Nuclear Information System (INIS)

Adam, Vojtech; Chudobova, Dagmar; Tmejova, Katerina; Cihalova, Kristyna; Krizkova, Sona; Guran, Roman; Kominkova, Marketa; Zurek, Michal; Kremplova, Monika; Jimenez, Ana Maria Jimenez; Konecna, Marie

2014-01-01

This study was focused on the application of electrochemical methods for studying of bacterial strains Escherichia coli and Escherichia coli expressing human metallothionein gene (MT-3) before and after the application of cadmium and/or lead ions in four concentrations (25, 50, 75 and 150 μM). Bacterial strains Escherichia coli and Escherichia coli expressing human metallothionein gene (MT-3) were used like model organisms for studying of metals influence to metallothionein expression. Metallothionein was isolated using fast protein liquid chromatography and quantified by electrochemical methods. The occurrence of metallothionein in E.coli was confirmed by gel electrophoresis by the presence of the bands at 15 (MT dimer) and 22 kDa (MT trimer). The changes in electrochemical records due to the interactions of metallothioneins (MT-3 and MT-2A) with cadmium and lead ions showed decline of Cat2 signal of MT with the increasing interaction time because of metal ions binding to cysteines. Electrochemical determination also revealed that Cd(II) remains in E. coli cells in the higher amount than Pb (II). Opposite situation was found at E. coli–MT-3 strain. The antimicrobial effect of cadmium ions was determined by IC 50 and was statistically calculated as 39.2 and 95.5 μM for E. coli without cloned MT-3 and E. coli carrying MT-3 gene, respectively. High provided concentration IC 50 in strains after lead ions application (352.5 μM for E. coli without cloning and 207.0 μM for E. coli carrying cloned MT-3 gene) indicates lower toxicity of lead ions on bacterial strains compared to the cadmium ions
Antibiotic Resistance Characterization of Environmental E. coli Isolated from River Mula-Mutha, Pune District, India.

Science.gov (United States)

Dhawde, Rutuja; Macaden, Ragini; Saranath, Dhananjaya; Nilgiriwala, Kayzad; Ghadge, Appasaheb; Birdi, Tannaz

2018-06-12

In the current study, ceftazidime- and ciprofloxacin-resistant—or dual drug-resistant (DDR)— E. coli were isolated from river Mula-Mutha, which flows through rural Pune district and Pune city. The DDR E. coli were further examined for antibiotic resistance to six additional antibiotics. The study also included detection of genes responsible for ceftazidime and ciprofloxacin resistance and vectors for horizontal gene transfer. Twenty-eight percent of the identified DDR E. coli were resistant to more than six antibiotics, with 12% being resistant to all eight antibiotics tested. Quinolone resistance was determined through the detection of qnrA , qnrB , qnrS and oqxA genes, whereas cephalosporin resistance was confirmed through detection of TEM, CTX-M-15, CTX-M-27 and SHV genes. Out of 219 DDR E. coli , 8.2% were qnrS positive and 0.4% were qnrB positive. Percentage of isolates positive for the TEM, CTX-M-15 and CTX-M-27 genes were 32%, 46% and 0.9%, respectively. None of the DDR E. coli tested carried the qnrA , SHV and oqxA genes. Percentage of DDR E. coli carrying Class 1 and 2 integrons (mobile genetic elements) were 47% and 8%, respectively. The results showed that antibiotic resistance genes (ARGs) and integrons were present in the E. coli isolated from the river at points adjoining and downstream of Pune city.

PCR Based Detection of Shiga Toxin Producing E. coli in Commercial Poultry and Related Environments

Directory of Open Access Journals (Sweden)

Homaira Anzum Himi

2015-02-01

Full Text Available Shiga toxin (Stx-producing E. coli (STEC is the most important foodborne pathogen which is the causal agent of mild diarrhea, bloody diarrhea, hemolytic-uremic syndrome (HUS in human. The present study was designed to determine the prevalence and identification of Shiga toxin (Stx-producing E. coli in poultry, detection of its source of infection in poultry and transmission pattern to human. For this purpose a total of 150 samples (cloacal swab-60, feed -15, water-15 and egg -60 were collected and analyzed in bacteriology laboratory by cultured in different bacteriological media followed by gram’s staining, biochemical tests and Polymerase Chain reaction (PCR. The PCR was performed by targeting 16s rRNA gene and shiga toxin producing gene in E. coli. Out of 150 collected samples, E. coli was found in 81 (54% samples. Presence of E. coli was 100% in both feed (n=15 and egg (n=60, whereas 10% in cloacal swab (n=6. Water samples were totally free of E. coli. The stx2 gene was detected in all samples whether all samples were negative for stx1 gene. The study revealed that, poultry feed acts as a source of E. coli infection in poultry, which may be transmitted to environment and human via meat or eggs. Antibiotic sensitivity test revealed that isolated bacteria were highly sensitive to Ciprofloxacin.
Distribution patterns study of Escherichia coli as an Indicator for ground water quality at Matraman District, East Jakarta

Science.gov (United States)

Anisah, U.; Iswanto, B.; Rinanti, A.

2018-01-01

The purpose of this study was to determine the distribution pattern E.coli as indicators of ground water contamination by fecal coliforms at Matraman District, East Jakarta, Indonesia (106049‧35″E 06010‧37″LS) consisting of six sub-districts (Utan Kayu Selatan, Utan Kayu Utara, Kayu Manis, Pal Meriam, Kebon Manggis and Pisangan Baru). The presence of E.coli examined by the method of Most Probable Number (MPN) according to SNI 01-2332.1-2006 about the determination of coliforms and E.coli in fishery products which consists of three stages of tests in a row, the estimation, determination or confirmation and complementary or morphology test. Matraman District is a densely populated area and the distance between septic tank and well is inadequate, both with their own’s septic tank or with neighbors’s septic tank. The result of sample analysis shows that E.coli counts exceeds water quality standards in accordance with regulation Health Ministry No.492/2010 concerning the drinking water quality requirements. The lowest MPN number is 3 MPN/100 ml and the highest number of E. coli is more than1100 MPN/100 ml. The temperature, pH and DO0 on average are 27.520C, 5.59 and 2.24 mg/L. This study is expected to be a reference in the use of ground water for daily activities in the district Matraman.
Occurrence and characterisation of pathogenic Escherichia coli isolated from beef meat imported from South Africa and marketed in united Arab Emirates

Science.gov (United States)

Dulaimi, Samar Abdulkareem Khalifa Al; Ibrahim, Nazlina

2018-04-01

This study is aimed at determining the presence of Escherichia coli and characterizing the availability of Shiga toxin gene in beef meat samples imported from South Africa. Meat samples (n=47) were randomly collected from meat sections at different supermarkets in the United Arab Emirates (UAE) from the beginning of August 2016 till the end of March 2017. Samples were diluted and inoculated on MacConkey agar and Eosin methylene blue agar (EMB), and the colony forming units (CFU) were recorded. API 20E identification kit was used for biochemical identification of E. coli. Detection of the 16S rRNA and shiga toxin genes by PCR amplification was done. Our results revealed that 14 (29.7%) out of the total 47 samples were positive for E. coli. The bacterial burden of E. coli as determined by colony growth showed variable level of contamination. From the PCR amplification, the shiga toxin gene carried by the E. coli is the Stx2 gene. This study revealed moderately high contamination levels of E. coli in beef samples imported from South Africa and marketed in UAE which mostly carries the shiga toxin gene Stx2.
Current pathogenic Escherichia coli foodborne outbreak cases and therapy development.

Science.gov (United States)

Yang, Shih-Chun; Lin, Chih-Hung; Aljuffali, Ibrahim A; Fang, Jia-You

2017-08-01

Food contamination by pathogenic microorganisms has been a serious public health problem and a cause of huge economic losses worldwide. Foodborne pathogenic Escherichia coli (E. coli) contamination, such as that with E. coli O157 and O104, is very common, even in developed countries. Bacterial contamination may occur during any of the steps in the farm-to-table continuum from environmental, animal, or human sources and cause foodborne illness. To understand the causes of the foodborne outbreaks by E. coli and food-contamination prevention measures, we collected and investigated the past 10 years' worldwide reports of foodborne E. coli contamination cases. In the first half of this review article, we introduce the infection and symptoms of five major foodborne diarrheagenic E. coli pathotypes: enteropathogenic E. coli (EPEC), Shiga toxin-producing E. coli/enterohemorrhagic E. coli (STEC/EHEC), Shigella/enteroinvasive E. coli (EIEC), enteroaggregative E. coli (EAEC), and enterotoxigenic E. coli (ETEC). In the second half of this review article, we introduce the foodborne outbreak cases caused by E. coli in natural foods and food products. Finally, we discuss current developments that can be applied to control and prevent bacterial food contamination.
Antibiogram of E. coli serotypes isolated from children aged under ...

African Journals Online (AJOL)

Background: Diarrheal disease and its complications remain a major cause of morbidity and mortality in children. The prevalence and antibiogram of E. coli as causative agents of diarrhea vary from region to region, and even within countries in the same geographical area. Objectives: To determine the serotype and ...
Prevalence and Antibiogram Profiling of Escherichia coli Pathotypes Isolated from the Kat River and the Fort Beaufort Abstraction Water

Science.gov (United States)

Nontongana, Nolonwabo; Sibanda, Timothy; Ngwenya, Elvis; Okoh, Anthony I.

2014-01-01

Escherichia coli is a widespread bacterium encompassing a variety of strains, ranging from highly pathogenic strains, causing worldwide outbreaks of severe diseases to avirulent, well characterized safe laboratory strains. This study evaluated the prevalence and antibiogram profiles of E. coli pathotypes isolated from the Kat River and Fort Beaufort abstraction water. A total of 171 out of 278 confirmed E. coli isolates were positive for at least one pathogenic determinant and these included enteropathogenic E. coli (6%), enterotoxigenic E. coli (47%), uropathogenic E. coli (2%), neonatal meningitis E. coli (5%), diffusely adherent E. coli (1%) and enterohaemorrhagic E. coli (1%). Interestingly, enteroinvasive and enteroaggregative E. coli were not detected. The phenotypic antibiogram profiles of the isolates revealed that all were resistant to penicillin G, while 98% and 38% of the pathotypes were resistant to ampicillin and trimethoprim-sulphamethoxazole, respectively. About 8% of the isolates were resistant to streptomycin. More than half of the isolates exhibited multiple antibiotic resistance with 44% being resistant to three antibiotics and 8% resistant to four antibiotics. We conclude that the Kat River is a reservoir of potentially virulent antibiotic resistant E. coli strains that can cause serious health risks to humans who drink raw water from this river, or in the case that consumption of treated drinking water coincides with failed drinking water processes. PMID:25119699
E. coli O124 K72 alters the intestinal barrier and the tight junctions proteins of guinea pig intestine.

Science.gov (United States)

Ren, Xiaomeng; Zhu, Yanyan; Gamallat, Yaser; Ma, Shenhao; Chiwala, Gift; Meyiah, Abdo; Xin, Yi

2017-10-01

Our research group previously isolated and identified a strain of pathogenic Escherichia coli from clinical samples called E. coli O124 K72. The present study was aimed at determining the potential effects of E. coli O124 K72 on intestinal barrier functions and structural proteins integrity in guinea pig. Guinea pigs were grouped into three groups; control (CG); E. coli O124 K72 (E. coli); and probiotics Lactobacillus rhamnosus (LGG). Initially, we create intestinal dysbiosis by giving all animals Levofloxacin for 10days, but the control group (CG) received the same volume of saline. Then, the animals received either E. coli O124 K72 (E. coli) or Lactobacillus rhamnosus (LGG) according to their assigned group. E. coli O124 K72 treatment significantly affected colon morphology and distorted intestinal barrier function by up-regulating Claudin2 and down-regulating Occludin. In addition, E. coli upregulated the mRNA expression of MUC1, MUC2, MUC13 and MUC15. Furthermore, suspected tumor was found in the E. coli treated animals. Our results suggested that E. coli O124 K72 strain has adverse effects on intestinal barrier functions and is capable of altering integrity of structural proteins in guinea pig model while at same time it may have a role in colon carcinogenesis. Copyright © 2017 Elsevier Masson SAS. All rights reserved.
Prevalence and Antibiogram Profiling of Escherichia coli Pathotypes Isolated from the Kat River and the Fort Beaufort Abstraction Water

Directory of Open Access Journals (Sweden)

Nolonwabo Nontongana

2014-08-01

Full Text Available Escherichia coli is a widespread bacterium encompassing a variety of strains, ranging from highly pathogenic strains, causing worldwide outbreaks of severe diseases to avirulent, well characterized safe laboratory strains. This study evaluated the prevalence and antibiogram profiles of E. coli pathotypes isolated from the Kat River and Fort Beaufort abstraction water. A total of 171 out of 278 confirmed E. coli isolates were positive for at least one pathogenic determinant and these included enteropathogenic E. coli (6%, enterotoxigenic E. coli (47%, uropathogenic E. coli (2%, neonatal meningitis E. coli (5%, diffusely adherent E. coli (1% and enterohaemorrhagic E. coli (1%. Interestingly, enteroinvasive and enteroaggregative E. coli were not detected. The phenotypic antibiogram profiles of the isolates revealed that all were resistant to penicillin G, while 98% and 38% of the pathotypes were resistant to ampicillin and trimethoprim-sulphamethoxazole, respectively. About 8% of the isolates were resistant to streptomycin. More than half of the isolates exhibited multiple antibiotic resistance with 44% being resistant to three antibiotics and 8% resistant to four antibiotics. We conclude that the Kat River is a reservoir of potentially virulent antibiotic resistant E. coli strains that can cause serious health risks to humans who drink raw water from this river, or in the case that consumption of treated drinking water coincides with failed drinking water processes.
New evidence on the role of catalase in Escherichia coli-mediated biocorrosion

International Nuclear Information System (INIS)

Baeza, S.; Vejar, N.; Gulppi, M.; Azocar, M.; Melo, F.; Monsalve, A.; Pérez-Donoso, J.; Vásquez, C.C.; Pavez, J.; Zagal, J.H.; Zhou, X.; Thompson, G.E.; Páez, M.A.

2013-01-01

Highlights: ► MIC on stainless by catalase deficient Escherichia coli bacteria reveals the enzyme influence. ► The localized damage was greater in the presence of the wild E. coli. ► Catalase assists oxygen generation by disproportionation of H 2 O 2 to H 2 O and O 2 . - Abstract: The role of catalase on the microbiologically influenced corrosion mechanism by Escherichia coli (E. coli) has been examined, employing wild type and catalase-deficient cells. The bacteria were cultured for different times in the presence of AISI 316L stainless steel samples. The morphologies of the metallic surfaces covered by biofilms were studied by optical microscopy. The localized corrosion catalyzed by the bacteria was followed by scanning electron microscopy after immersion in the bacterial culture for different times. Susceptibility to corrosion was further investigated by potentiodynamic measurements. It was found that wild type E. coli is more aggressive than the mutant one, suggesting a role for catalase in increasing the kinetics of the cathodic reaction and, consequently, the global corrosion process. This correlates with oxygen uptake kinetics, as determined by differential pulse voltammetry on a pyrolytic graphite electrode modified with cobalt phthalocyanine, which was higher in the presence of wild type E. coli. When H 2 O 2 was deliberately added to the culture medium, wild type E. coli catalyzed oxygen disproportionation more efficiently than the mutant derivative, thus limiting H 2 O 2 accumulation in the medium and, hence, bacterial poisoning. In fact, the reduced adhesion of mutant cells to the metal substrate is apparently the result of H 2 O 2 accumulation in the culture broth. Thus, the rapid consumption of oxygen and peroxide in the presence of wild type E. coli is associated with the catalysis of H 2 O 2 disproportionation to water and oxygen. On the stainless steel, however, a dual mechanism of oxygen reduction, i.e. through formation of hydrogen peroxide
Determinants of virulence and of resistance to ceftiofur, gentamicin, and spectinomycin in clinical Escherichia coli from broiler chickens in Québec, Canada.

Science.gov (United States)

Chalmers, Gabhan; Cormier, Ashley C; Nadeau, Marie; Côté, Geneviève; Reid-Smith, Richard J; Boerlin, Patrick

2017-05-01

Antimicrobials are frequently used for the prevention of avian colibacillosis, with gentamicin used for this purpose in Québec until 2003. Ceftiofur was also used similarly, but voluntarily withdrawn in 2005 due to increasing resistance. Spectinomycin-lincomycin was employed as a replacement, but ceftiofur use was partially reinstated in 2007 until its definitive ban by the poultry industry in 2014. Gentamicin resistance frequency increased during the past decade in clinical Escherichia coli isolates from broiler chickens in Québec, despite this antimicrobial no longer being used. Since this increase coincided with the use of spectinomycin-lincomycin, co-selection of gentamicin resistance through spectinomycin was suspected. Therefore, relationships between spectinomycin, gentamicin, and ceftiofur resistance determinants were investigated here. The distribution of 13 avian pathogenic E. coli virulence-associated genes and their association with spectinomycin resistance were also assessed. A sample of 586 E. coli isolates from chickens with colibacillosis in Québec between 2009 and 2013 was used. The major genes identified for resistance to ceftiofur, gentamicin, and spectinomycin were bla CMY , aac(3)-VI, and aadA, respectively. The aadA and aac(3)-VI genes were strongly associated and shown to be located on a modified class 1 integron. The aadA and bla CMY genes were negatively associated, but when present together, were generally located on the same plasmids. No statistical positive association was observed between aadA and virulence genes, and virulence genes were only rarely detected on plasmids encoding spectinomycin resistance. Thus, the use of spectinomycin-lincomycin may likely select for gentamicin but not ceftiofur resistance, nor for any of the virulence-associated genes investigated. Copyright © 2017 Elsevier B.V. All rights reserved.
Experimental induced avian E. coli salpingitis

DEFF Research Database (Denmark)

Olsen, Rikke Heidemann; Thøfner, Ida; Pors, Susanne Elisabeth

2016-01-01

Several types of Escherichia coli have been associated with extra-intestinal infections in poultry, however, they may vary significantly in their virulence potential. The aim of the present study was to investigate the virulence of five strains of E. coli obtained from different disease......) had a distinct ability to cause disease. Results of the study shows major differences in virulence of different strains of E. coli in ascending infections; however, there was no indication of tissue-specific adaptation, since strains obtained from lesions unrelated to the reproductive system were...... fully capable of causing experimental infection. In conclusion, the study provides evidence for the clinical outcome of infection with E. coli in poultry is largely influenced by the specific strain as well as individual host factors....
Immunocytochemical localization of the elongation factor Tu in E. coli cells

NARCIS (Netherlands)

Slot, J.W.; Schilstra, M.J.; Meide, P.H. van der; Posthuma, G.; Cremers, A.F.M.; Bosch, L.

1984-01-01

The localization of the elongation factor Tu (EF-Tu) in ultrathin cryosections of E. coli cells was determined with the electron microscope using a highly specific immunological labellin technique. EF-Tu is distributed almost homogeneously throughout the cytoplasm. Although it has often been
In vitro Clostridium perfringens and Escherichia coli toxin adsorption of Varium

Science.gov (United States)

Enteric disease agents, such as Clostridium perfringens and Escherichia coli, produce detrimental biotoxins that cause significant economic loss annually in the poultry industry. The objective of this study was to determine the in vitro biotoxin adsorption capability of Varium. An enzyme-linked im...
Molecular characterization of diarrheagenic Escherichia coli isolated from vegetables in Argentina.

Science.gov (United States)

González, Juliana; Cadona, Jimena S; Sanz, Marcelo; Bustamante, Ana V; Sanso, A Mariel

2017-11-16

The aim of this study was to investigate the prevalence of diarrheagenic E. coli strains in vegetables from the humid Pampa region, Argentina, and to determine the occurrence of serotypes and virulence genes in the isolates. A total of 373 fresh vegetable samples obtained from 41 different geographical points were examined. E. coli was detected in 38.6% of the samples. Ten isolates could be obtained from 14 samples presumptively positive for diarrheagenic E. coli: 8 were identified as atypical Enteropathogenic E. coli (aEPEC) and 2 as Verocytotoxigenic E. coli (VTEC). Lettuce and beet were the vegetables most frequently contaminated with pathogenic E. coli. The isolates belonged to serotypes O1:H7, O28:H19, O39:H40, O86:H31, O132:H8, O139:H20, O178:H7 and O178:H19, some of which reportedly have caused human illness, and one isolate resulted non typeable. Taking into account the distribution of 16 nle genes, 7 profiles were detected. On the other hand, all tested isolates harbored the gene encoding for the adhesin HcpA. Other adhesion related genes were also identified: ecpA and elfA were detected in 90%, lpfA 0113 in 60%, and ehaA in 50% of the isolates meanwhile ihaA was only observed in O178:H19 isolate. This VTEC isolate harbored, also, Cdt-V toxin and megaplasmid encoding genes such as espP, subA and epeA and exhibited a strong cytotoxic effect. These data is the first molecular E. coli report that confirms the presence of E. coli pathotypes circulating among vegetables in Argentina. Genetic characterization showed that in addition to eae or vtx genes, isolates obtained from vegetables harbored genes encoding other toxins, adhesins, and components related to the type III secretion system that could contribute to their virulence. In conclusion, this research shows that vegetables in Argentina may be the source of VTEC and EPEC infections in the community and therefore, they should be considered as vehicles for transmission of these potentially pathogenic
Risk of Transmission of Antimicrobial Resistant Escherichia coli from Commercial Broiler and Free-Range Retail Chicken in India.

Science.gov (United States)

Hussain, Arif; Shaik, Sabiha; Ranjan, Amit; Nandanwar, Nishant; Tiwari, Sumeet K; Majid, Mohammad; Baddam, Ramani; Qureshi, Insaf A; Semmler, Torsten; Wieler, Lothar H; Islam, Mohammad A; Chakravortty, Dipshikha; Ahmed, Niyaz

2017-01-01

Multidrug-resistant Escherichia coli infections are a growing public health concern. This study analyzed the possibility of contamination of commercial poultry meat (broiler and free-range) with pathogenic and or multi-resistant E. coli in retail chain poultry meat markets in India. We analyzed 168 E. coli isolates from broiler and free-range retail poultry (meat/ceca) sampled over a wide geographical area, for their antimicrobial sensitivity, phylogenetic groupings, virulence determinants, extended-spectrum-β-lactamase (ESBL) genotypes, fingerprinting by Enterobacterial Repetitive Intergenic Consensus (ERIC) PCR and genetic relatedness to human pathogenic E. coli using whole genome sequencing (WGS). The prevalence rates of ESBL producing E. coli among broiler chicken were: meat 46%; ceca 40%. Whereas, those for free range chicken were: meat 15%; ceca 30%. E. coli from broiler and free-range chicken exhibited varied prevalence rates for multi-drug resistance (meat 68%; ceca 64% and meat 8%; ceca 26%, respectively) and extraintestinal pathogenic E. coli (ExPEC) contamination (5 and 0%, respectively). WGS analysis confirmed two globally emergent human pathogenic lineages of E. coli , namely the ST131 ( H 30-Rx subclone) and ST117 among our poultry E. coli isolates. These results suggest that commercial poultry meat is not only an indirect public health risk by being a possible carrier of non-pathogenic multi-drug resistant (MDR)- E. coli , but could as well be the carrier of human E. coli pathotypes. Further, the free-range chicken appears to carry low risk of contamination with antimicrobial resistant and extraintestinal pathogenic E. coli (ExPEC). Overall, these observations reinforce the understanding that poultry meat in the retail chain could possibly be contaminated by MDR and/or pathogenic E. coli.
Antibacterial Effect of Curcuma longa (Turmeric) Against Staphylococcus aureus and Escherichia coli.

Science.gov (United States)

Afrose, R; Saha, S K; Banu, L A; Ahmed, A U; Shahidullah, A S; Gani, A; Sultana, S; Kabir, M R; Ali, M Y

2015-07-01

This observational study was conducted during the period from July 2010 to June 2011 in the Department of Pharmacology in the collaboration of Department of Microbiology, Mymensingh Medical College, Mymensingh to determine the profile of antibacterial effect of Crude Turmeric paste aqueous turmeric extract, and standard antibiotic Amikacin against Staphylococcus aureus and Escherichia coli. Three separate experiments were done e.g. (Expt- I) Inhibitory effect of Crude Turmeric paste incorporated into nutrient agar (NA) media, (Expt- II) Minimum inhibitory concentration of (a) Aqueous Turmeric extract and (b) Amikacin by broth dilution technique and (Expt-III) their subculture study in nutrient agar (NA) media for confirmation of respective results of previous experiments. Inhibitory effects were observed against the growth of Staph Aureus and Esch coli at 10% and 30% respectively of Crude Turmeric paste incorporated into NA media. The broth dilution technique was followed to determine the MIC of Aqueous Turmeric extract and Amikacin. The MIC of Aqueous Turmeric extract was 800 μg/ml against Staph aureus and that against Esch coli was 2000 μg/ml and the MIC of Amikacin was 10 μg/ml for both the bacteria. The MIC of Amikacin was the lowest in comparison to MIC of Aqueous Turmeric extract for complete inhibition of growth of Staph aureus and Esch coli. The subculture study showed similar results with that of previous experiments in terms of inhibitory effects of Crude Turmeric paste and MIC of Aqueous Turmeric extract and Amikacin against all of the organisms studied.
Antibiotic Resistance Profile in Relation to Phylogenetic Background in Escherichia coli Isolated From Fecal Samples of Healthy Ostrich

Directory of Open Access Journals (Sweden)

Elham Mohamadi

2015-05-01

Full Text Available Background: E. coli is regarded as a reservoir for antibiotic resistance in foods of animal origin. E. coli can be categories into four mainphylogenetic groups (A, B1, B2 and D. The commensal E. coli strains mostly are assigned to the phylo-groups A and B1. Objectives: The purposes of this study were to determine the phylogenetic group/subgroups and antibiotic resistance patterns of ostrich E. coli isolates in Iran. Materials and Methods: A total of 126 E. coli isolates were obtained from cloacae swabs of the healthy ostrich in Kerman, Iran. The E. coliisolates were confirmed using biochemical API 20E identification system. The confirmed isolates were studied to determine phylogeneticbackground by PCR. The isolates were tested for antibiotic resistance against 12 different antibiotic disk by disk diffusion method. Results: Phylotyping of E. coli isolates indicated that 74 isolates belonged to A, 27 isolates to B1, 7 isolates to B2, and 18 isolates to D groups.Also the isolates fell into six phylogenetic subgroups, including 34 isolates in A0, 40 isolates in A1, one isolate in B22, 6 isolates in B23, 11isolates in D1 and 7 isolates in subgroup D2. In the examined E. coli isolates, the maximum rate of resistance was against tetracycline, andthe minimum rate of resistance was against amoxicillin. Twenty three antibiotic resistance patterns were detected among the isolates. Thecefoxitin and tetracycline resistance pattern was the most prevalent in the isolates that belonged to phylo-group A. Conclusions: In conclusion, the result of the present study revealed a low frequency of antibiotic resistance in ostrich E. coli isolates.The antibiotic resistance patterns were in relation to A and D phylogenetic groups. Further studies are needed to better understand thedistribution of phylogenetic groups in poultry isolates.
A biosensor platform for rapid detection of E. coli in drinking water.

Science.gov (United States)

Hesari, Nikou; Alum, Absar; Elzein, Mohamad; Abbaszadegan, Morteza

2016-02-01

There remains a need for rapid, specific and sensitive assays for the detection of bacterial indicators for water quality monitoring. In this study, a strategy for rapid detection of Escherichia coli in drinking water has been developed. This strategy is based on the use of the substrate 4-methylumbelliferyl-β-d-glucuronide (MUG), which is hydrolyzed rapidly by the action of E. coli β-d-glucuronidase (GUD) enzyme to yield a fluorogenic 4-methylumbelliferone (4-MU) product that can be quantified and related to the number of E. coli cells present in water samples. In this study, the detection time required for the biosensor response ranged between 20 and 120 min, depending on the number of bacteria in the sample. This approach does not need extensive sample processing with a rapid detection capability. The specificity of the MUG substrate was examined in both, pure cultures of non-target bacterial genera such as Klebsiella, Salmonella, Enterobacter and Bacillus. Non-target substrates that included 4-methylumbelliferyl-β-d-galactopyranoside (MUGal) and l-leucine β-naphthylamide aminopeptidase (LLβ-N) were also investigated to identify nonspecific patterns of enzymatic activities in E. coli. GUD activity was found to be specific for E. coli and no further enzymatic activity was detected by other species. In addition, fluorescence assays were performed for the detection of E. coli to generate standard curves; and the sensitivity of the GUD enzymatic response was measured and repeatedly determined to be less than 10 E. coli cells in a reaction vial. The applicability of the method was tested by performing multiple fluorescence assays under pure and mixed bacterial flora in environmental samples. The results of this study showed that the fluorescence signals generated in samples using specific substrate molecules can be utilized to develop a bio-sensing platform for the detection of E. coli in drinking water. Furthermore, this system can be applied independently or
Development and maturation of Escherichia coli K-12 biofilms

DEFF Research Database (Denmark)

Reisner, A.; Haagensen, J.A.J.; Schembri, Mark

2003-01-01

The development and maturation of E. coli biofilms in flow-chambers was investigated. We found that the presence of transfer constitutive IncF plasmids induced biofilm development forming structures resembling those reported for Pseudomonas aeruginosa . The development occurred in a step...... occurred in conjugation pilus proficient plasmid-carrying strains. The final shapes of the expanding structures in the mature biofilm seem to be determined by the pilus configuration, as various mutants affected in the processing and activity of the transfer pili displayed differently structured biofilms....... We further provide evidence that flagella, type 1 fimbriae, curli and Ag43 are all dispensable for the observed biofilm maturation. In addition, our results indicate that cell-to-cell signalling mediated by autoinducer 2 (AI-2) is not required for differentiation of E. coli within a biofilm community...
Diarrheagenic Escherichia coli: Prevalence and Pathotype Distribution in Children from Peruvian Rural Communities.

Science.gov (United States)

Acosta, Gonzalo J; Vigo, Natalia I; Durand, David; Riveros, Maribel; Arango, Sara; Zambruni, Mara; Ochoa, Theresa J

2016-09-07

Diarrheagenic Escherichia coli (DEC) are common pathogens of childhood gastrointestinal infections worldwide. To date, research tracking DEC has mainly been completed in urban areas. This study aims to determine the prevalence and pathotype distribution of DEC strains in children from rural Peruvian communities and to establish their association with malnutrition. In this prospective cohort, 93 children aged 6-13 months from rural communities of Urubamba (Andes) and Moyobamba (jungle) were followed for 6 months. Diarrheal and control stool samples were analyzed using multiplex real-time polymerase chain reaction to identify the presence of virulence genes of DEC strains. The overall isolation rate of DEC was 43.0% (352/820). Enteroaggregative E. coli (EAEC, 20.4%), enteropathogenic E. coli (EPEC, 14.2%), and diffusely aggregative E. coli (DAEC, 11.0%) were the most prevalent pathotypes. EAEC was more frequently found in Moyobamba samples (P jungle of Peru. In addition, children with a greater decline in their growth rate had higher EAEC isolation rates, highlighting the importance of this pathogen in child malnutrition. © The American Society of Tropical Medicine and Hygiene.

Escherichia coli challenge and one type of smectite alter intestinal barrier of pigs.

Science.gov (United States)

Almeida, Juliana Abranches Soares; Liu, Yanhong; Song, Minho; Lee, Jeong Jae; Gaskins, H Rex; Maddox, Carol Wolfgang; Osuna, Orlando; Pettigrew, James Eugene

2013-12-20

An experiment was conducted to determine how an E. coli challenge and dietary clays affect the intestinal barrier of pigs. Two groups of 32 pigs (initial BW: 6.9 ± 1.0 kg) were distributed in a 2 × 4 factorial arrangement of a randomized complete block design (2 challenge treatments: sham or E. coli, and 4 dietary treatments: control, 0.3% smectite A, 0.3% smectite B and 0.3% zeolite), with 8 replicates total. Diarrhea score, growth performance, goblet cell size and number, bacterial translocation from intestinal lumen to lymph nodes, intestinal morphology, and relative amounts of sulfo and sialo mucins were measured. The E. coli challenge reduced performance, increased goblet cell size and number in the ileum, increased bacterial translocation from the intestinal lumen to the lymph nodes, and increased ileal crypt depth. One of the clays (smectite A) tended to increase goblet cell size in ileum, which may indicate enhanced protection. In conclusion, E. coli infection degrades intestinal barrier integrity but smectite A may enhance it.
Inactivation and Gene Expression of a Virulent WastewaterEscherichia coliStrain and the Nonvirulent CommensalEscherichia coliDSM1103 Strain upon Solar Irradiation

KAUST Repository

Aljassim, Nada I.; Mantilla-Calderon, David; Wang, Tiannyu; Hong, Pei-Ying

2017-01-01

This study examined the decay kinetics and molecular responses of two Escherichia coli strains upon solar irradiation. The first is E. coli PI-7, a virulent and antibiotic-resistant strain that was isolated from wastewater and carries the emerging NDM-1 antibiotic resistance gene. The other strain, E. coli DSM1103, displayed lower virulence and antibiotic resistance than E. coli PI-7. In a buffer solution, E. coli PI-7 displayed a longer lag phase prior to decay and a longer half-life compared with E. coli DSM1103 (6.64 ± 0.63 h and 2.85 ± 0.46 min vs 1.33 ± 0.52 h and 2.04 ± 0.36 min). In wastewater, both E. coli strains decayed slower than they did in buffer. Although solar irradiation remained effective in reducing the numbers of both strains by more than 5-log10 in <24 h, comparative genomics and transcriptomics revealed differences in the genomes and overall regulation of genes between the two E. coli strains. A wider arsenal of genes related to oxidative stress, cellular repair and protective mechanisms were upregulated in E. coli PI-7. Subpopulations of E. coli PI-7 expressed genes related to dormancy and persister cell formation during the late decay phase, which may have accounted for its prolonged persistence. Upon prolonged solar irradiation, both E. coli strains displayed upregulation of genes related to horizontal gene transfer and antibiotic resistance. Virulence functions unique to E. coli PI-7 were also upregulated. Our findings collectively indicated that, whereas solar irradiation is able to reduce total cell numbers, viable E. coli remained and expressed genes that enable survival despite solar treatment. There remains a need for heightened levels of concern regarding risks arising from the dissemination of E. coli that may remain viable in wastewater after solar irradiation.
Inactivation and Gene Expression of a Virulent WastewaterEscherichia coliStrain and the Nonvirulent CommensalEscherichia coliDSM1103 Strain upon Solar Irradiation

KAUST Repository

Aljassim, Nada I.

2017-03-06

This study examined the decay kinetics and molecular responses of two Escherichia coli strains upon solar irradiation. The first is E. coli PI-7, a virulent and antibiotic-resistant strain that was isolated from wastewater and carries the emerging NDM-1 antibiotic resistance gene. The other strain, E. coli DSM1103, displayed lower virulence and antibiotic resistance than E. coli PI-7. In a buffer solution, E. coli PI-7 displayed a longer lag phase prior to decay and a longer half-life compared with E. coli DSM1103 (6.64 ± 0.63 h and 2.85 ± 0.46 min vs 1.33 ± 0.52 h and 2.04 ± 0.36 min). In wastewater, both E. coli strains decayed slower than they did in buffer. Although solar irradiation remained effective in reducing the numbers of both strains by more than 5-log10 in <24 h, comparative genomics and transcriptomics revealed differences in the genomes and overall regulation of genes between the two E. coli strains. A wider arsenal of genes related to oxidative stress, cellular repair and protective mechanisms were upregulated in E. coli PI-7. Subpopulations of E. coli PI-7 expressed genes related to dormancy and persister cell formation during the late decay phase, which may have accounted for its prolonged persistence. Upon prolonged solar irradiation, both E. coli strains displayed upregulation of genes related to horizontal gene transfer and antibiotic resistance. Virulence functions unique to E. coli PI-7 were also upregulated. Our findings collectively indicated that, whereas solar irradiation is able to reduce total cell numbers, viable E. coli remained and expressed genes that enable survival despite solar treatment. There remains a need for heightened levels of concern regarding risks arising from the dissemination of E. coli that may remain viable in wastewater after solar irradiation.
Risk of Escherichia coli O157:H7 infection linked to the consumption of beef

Directory of Open Access Journals (Sweden)

Premarathne, J.M.K.J.K

2017-05-01

Full Text Available Escherichia coli O157:H7 is a major food-borne pathogen that has resulted in numerous outbreaks around the world. Widespread distribution of the organism in various ecological niches impedes the control measures. This study aimed to detect and quantify E. coli O157:H7 in beef sold in wet markets and hypermarkets in Malaysia and to determine the risk of E. coli O157:H7 infection linked to consumption of beef. The rfbO157 and flicH7 primers targeted on somatic antigen (O157 and flagellar antigen (H7 respectively of E. coli O157:H7 was used for the MPN-PCR method. A total of 99 beef samples were collected from local wet markets and hypermarkets. The highest E. coli O157:H7 contamination rate was observed in beef samples collected from wet markets (89.50%, whereas the contamination rate in hyper market A and B were compratively low (35.35 and 20% respectively. However, the microbial load was highest in the beef samples from hypermarket A (1100 MPN/g while E. coli O157:H7 bacterial load in beef samples from hypermarket B and wet market ranged from 3 to 93 MPN/g and 3 to 240 MPN/g, respectively. Using the Quantitative Microbial Risk Assessment (QMRA approach the risk was estimated incorporating the findings of the prevalence study and predictions based on home storage, cooking and consumption patterns. Three different exposure pathways were investigated to estimate the risk associated with contaminated beef and Monte Carlo simulation was used to determine the level of uncertainty. The developed model predicated that consumption of contaminated beef can be accountable for 1.83E+06 E. coli O157:H7 cases per year in Malaysia. The reliability of the model, data gaps and further research needs, is discussed. Through continuous improvement Quantitative Microbial Risk Assessment provides valuable insight into controlling and prevention strategies.
CHARACTERIZATION OF EXTENDED-SPECTRUM Β-LACTAMASE-PRODUCING ESCHERICHIA COLI STRAINS ISOLATED FROM DAIRY PRODUCTS

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Rahem Khoshbakht

2014-02-01

Full Text Available Extended-spectrum β-lactamases (ESBLs are enzymes that hydrolyze the β-lactam ring, and ESBL-producing E. coli has rapidly spread worldwide with pose a serious hazard for humans. The aim of this study was to determine the prevalence of ESBL producing E. coli and molecular evaluation of four ESBL-associated genes among E. coli strains isolated from milk and cheese in southern Iran. Antibiotic susceptibility test was carried out for a total of 150 isolates of E. coli, previously collected from dairy products. ESBL production was screened using a double-disc synergy test (DDST and presence of four ESBL genes (PER, VEB, TEM and CTX-M was tested using PCR. Among 150 E. coli strains 57 (38% isolates were identified as ESBL-producing strains. All ESBL positive isolates could be typed for one or more genes and the most prevalent ESBL-associated gene was CTX-M (80.7%. The PER gene was not present among isolates. Isolates showed high susceptibility to imipe¬nem and cefoxitin. The results showed the high prevalence of ESBL producing E. coli strains among dairy products and high occurrence of CTX-M-associated ESBL activity among isolates indicating the hazards of increasing the strains with antibiotic resistance which can transfer to human trough the dairy food products.
Molecular characterization and phylogeny of Shiga toxin-producing E. coli (STEC) from imported beef meat in Malaysia.

Science.gov (United States)

Abuelhassan, Nawal Nouridaim; Mutalib, Sahilah Abdul; Gimba, Fufa Ido; Yusoff, Wan Mohtar

2016-09-01

This study aimed at determining the presence and characterization of Escherichia coli and Shiga toxin-producing E. coli (STEC) from imported frozen beef meats. Seventy-four (74) frozen imported beef meat samples from two countries, India (42 samples) and Australia (32 samples), were collected and tested for E. coli. These samples were purchased from the frozen meat sections of five different supermarkets in different locations in Selangor, Malaysia, from April 2012 to October 2014. A total of 222 E. coli strains were isolated from the meat samples; 126 strains were isolated from country A (India), and 96 E. coli strains were from country of origin B (Australia), respectively. A total of 70 E. coli strains were identified and characterized. All E. coli strains were isolated into Fluorocult medium and identified using API 20E kit. All selected E. coli strains were characterized for Shiga toxin genes (stx1 and stx2). All biochemically identified E. coli in this study were further subjected to molecular detection through polymerase chain reaction (PCR) amplification and characterization using 16S ribosomal RNA (rRNA) gene of Shiga toxin-producing E. coli. Of the 70 E. coli strains, 11 strains were positive for both Shiga toxin genes (stx1 and stx2) and 11 (11/70) strains were positive for stx1 gene, while 25 (25/70) strains were positive for stx2 gene. The analysis of 16S rRNA gene of all the E. coli isolates in this study was successfully sequenced and analyzed, and based on sequence data obtained, a phylogenetic tree of the 16S rRNA gene was performed using Clustal W programme in MEGA 6.06 software. Phylogenetic tree showed that the E. coli isolates in our study cluster with the strain of E. coli isolated in other countries, which further confirm that the isolates of E. coli in this study are similar to those obtained in other studies. As a result, all the strains obtained in this study proved to be a strain of pathogenic E. coli, which may cause a serious outbreak
In vitro anti-bacterial and anti-adherence effects of Lactobacillus delbrueckii subsp bulgaricus on Escherichia coli.

Science.gov (United States)

Abedi, D; Feizizadeh, S; Akbari, V; Jafarian-Dehkordi, A

2013-10-01

Considering the emergence of antibiotic resistance, scientists are interested in using new antimicrobial agents in the treatment of infectious diseases including infections of the enteric systems. Lactic acid bacteria have the great potential to produce antimicrobial compounds that inhibit and control pathogenic bacteria. The aim of this study was to determine the anti-bacterial and anti-adherence properties of Lactobacillus delbrueckii subsp bulgaricus against Escherichia coli. The antibacterial activity of L. delbrueckii was investigated using disc diffusion and spot on lawn methods. In vitro anti-adhesion effect of L. delbrueckii against E. coli was examined using Caco-2 cells. In anti-adhesion assay, three competition conditions including competitive inhibition, adhesion inhibition, and displacement were examined. In spot on lawn method the zone of growth inhibition of E. coli by L. delbrueckii was 21.1 mm. The cell free supernatant of L. delbrueckii showed a good antibacterial activity against E. coli which was mainly related to lactic acid produced by L. delbrueckii. When two bacteria added simultaneously (competitive inhibition) degree of inhibition of E. coli binding by L. delbrueckii was 77%. In adhesion inhibition assay, L. delbrueckii was able to exclude E. coli adherence by around 43.5%. Displacement assay showed that L. delbrueckii had strong displacement ability toward E. coli and reduction of E. coli attachment by bound L. delbrueckii was 81.3%. The results suggest that L. delbrueckii may be able to inhibit E. coli infection in the gut; however more studies including in vivo studies need to be performed.
Isolation, histopathology and antibiogram of Escherichia coli from pigeons (Columba livia

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Pankaj Dutta

2013-04-01

Full Text Available Aim: To know the prevalence of antibiotic resistant Escherichia coli among dead and/or diarrhoic pigeons in and around greater Guwahati. Materials and Methods: Samples were cultured from dead and/or diarrhoic pigeons and identification was done by standard methods. The sensitivity of the isolated E.coli strains to 15 antibiotics of human and veterinary use was also determined. Organs from those dead birds from which E.coli were recovered were processed according to the routine procedure for histopathological studies. Results: Out of 150 pigeons subjected to microbiological investigation, 91(60.67 % samples were found positive for E. coli.The most frequently occurring serotypes were O157 (9.89%, followed by O68, O121 (7.69%, O9, O75, O131 (5.49%, O2, O13, O22 (3.30%. Antibiogram investigation of the isolates revealed that 91isolates (100% exhibited resistance against Ampicillin followed by Nitro-furantoin (73.62%, Tetracycline (65.93 %, Oxytetracycline (62.63 % and Streptomycin (61.54. Gross changes of some birds showed fibrinous pericarditis and perihepatitis and coligranuloma in different organs like liver and serosal surface of intestine. Microscopically, severe congestion and haemorrhages in different organs such as liver, kidney, lung and intestine. In some cases thick layer of fibrinous exudates with large number of heterophills over the surface of liver and heart with early degenerative changes as well as focal necrosis. Conclusion: The result of this study suggests that antimicrobial-resistant pathogenic E.coli is present in pigeons in and around greater Guwahati. Surveillance programs may be introduced to monitor antimicrobial resistance of pathogenic E.coli in pigeons in and around greater guwahati. [Vet World 2013; 6(2.000: 91-94
Detection & characterization of necrotoxin producing Escherichia coli (NTEC) from patients with urinary tract infection (UTI).

Science.gov (United States)

Rahman, Helina; Deka, Manab

2014-04-01

Urinary tract infections (UTI) are a serious health problem affecting millions of people each year. Although appreciable work on various aspects of UTI including aetiology per se has been done, information on the emerging pathogens like necrotoxigenic Escherichia coli (NTEC) is largely lacking in India. In the present study E. coli isolates from patients with urinary tract infection from northeastern India were investigated for detection and characterization of NTEC. E. coli isolated and identified from urine samples of patients with UTI were serotyped. Antibiogram was determined by disc diffusion test. Plasmid profile was also determined. Virulence genes of NTEC (cnf1, cnf2, pap, aer, sfa, hly, afa) were detected by PCR assay. E.coli isolates carrying cnf gene (s) were identified as NTEC. A total of 550 E. coli were isolated and tested for the presence of cnf genes. Of these, 84 (15.27%) belonged to NTEC. The cnf1 gene was present in 52 (61.9%) isolates, cnf2 in 23 (27.4%) and 9 (10.7%) carried both cnf1 and cnf2 genes. All the NTEC strains were found to harbour the pap and aer genes. Serogroup O4 was found to be the most common among the 12 serogroups identified amongst the NTEC isolates. Majority of the isolates (96.4%) were sensitive to furazolidone and were highly resistant to ampicillin. NTEC were found to harbour different numbers of plasmids (1 to 7). No association was observed between the number of plasmids and the antibiotic resistance of the isolates. The results of the present study showed that about 15 per cent of E. coli isolates associated with UTI belonged to NTEC. More studies need to be done from other parts of the country.
Treatment of inflammatory bowel disease associated E. coli with ciprofloxacin and E. coli Nissle in the streptomycin-treated mouse intestine

DEFF Research Database (Denmark)

Petersen, Andreas Munk; Schjørring, Susanne; Gerstrøm, Sarah Choi

2011-01-01

E. coli belonging to the phylogenetic group B2 are linked to Inflammatory Bowel Disease (IBD). Studies have shown that antimicrobials have some effect in the treatment of IBD, and it has been demonstrated that E. coli Nissle has prophylactic abilities comparable to 5-aminosalicylic acid (5-ASA......) therapy in ulcerative colitis. The objective of this study was to test if ciprofloxacin and/or E. coli Nissle could eradicate IBD associated E. coli in the streptomycin-treated mouse intestine....
Phosphoribosylpyrophosphate synthetase of Escherichia coli. Properties of the purified enzyme and primary structure of the prs gene

DEFF Research Database (Denmark)

Hove-Jensen, Bjarne; Harlow, Kenneth W.; King, Cheryl J.

1986-01-01

of ADP. The nucleotide sequence of the E. coli prs gene has been determined and the coding segment established. The deduced amino acid sequence of P-Rib-PP synthetase contained 314 amino acid residues and the molecular weight was calculated as 34,060. The initiation site of transcription was determined......Phosphoribosylpyrophosphate (P-Rib-PP) synthetase of Escherichia coli has been purified to near homogeneity from a strain harboring the prs gene, encoding P-Rib-PP synthetase, on a multicopy plasmid. Analysis of the enzyme showed that it required inorganic phosphate for activity and for stability...
The antibacterial effect of four mouthwashes against streptococcus mutans and escherichia coli.

Science.gov (United States)

Ghapanchi, Janan; Lavaee, Fatemeh; Moattari, Afagh; Shakib, Mahmood

2015-04-01

To evaluate the antimicrobial properties of several mouthwash concentrations on oral Streptococcus mutans and Escherichia coli. The study was conducted at Shiraz Medicine School in 2011. Serial dilutions of Chlorohexidin, Oral B and Persica and Irsha (2,4,8,16,64,128) were prepared in Muller-Hinton media. Minimum inhibitory concentration was visually determined and defined as the lowest concentration of each oral washing which inhibited > 95% growth reduction compared to the growth control well. Chlorhexidine, Oral B and Irsha mouthwash inhibited Streptococcus mutans even with diluted concentrations. Also, Chlorhexidine and Oral B prohibited Escherichia coli with different potencies. But Persica had no antimicrobial activity against either Escherichia coli or Streptococcus mutans. Chlorhexidine, Irsha, and Oral B mouthwashes can be used for antimicrobial effects, especially on Streptococcus mutans. This chemical activity of mouthwashes is an adjuvant for mechanical removing of plaque. However, the antimicrobial effect of Persicaremains controversial.
Lipocalin 2 is protective against E. coli pneumonia

DEFF Research Database (Denmark)

Wu, Hong; Santoni-Rugiu, Eric; Ralfkiaer, Elisabeth

2010-01-01

Lipocalin 2 is a bacteriostatic protein that binds the siderophore enterobactin, an iron-chelating molecule produced by Escherichia coli (E. coli) that is required for bacterial growth. Infection of the lungs by E. coli is rare despite a frequent exposure to this commensal bacterium. Lipocalin 2...... is an effector molecule of the innate immune system and could therefore play a role in hindering growth of E. coli in the lungs....
Distribution of virulence determinants among antimicrobial-resistant and antimicrobial-susceptible Escherichia coli implicated in urinary tract infections.

Science.gov (United States)

Stephenson, Sam; Brown, P D

2016-01-01

Uropathogenic Escherichia coli (UPEC) rely on the correlation of virulence expression with antimicrobial resistance to persist and cause severe urinary tract infections (UTIs). We assessed the virulence pattern and prevalence among UPEC strains susceptible and resistant to multiple antimicrobial classes. A total of 174 non-duplicate UPEC strains from patients with clinically significant UTIs were analysed for susceptibility to aminoglycoside, antifolate, cephalosporin, nitrofuran and quinolone antibiotics for the production of extended-spectrum β-lactamases and for the presence of six virulence determinants encoding adhesins (afimbrial, Type 1 fimbriae, P and S-fimbriae) and toxins (cytotoxic necrotising factor and haemolysin). Relatively high resistance rates to nalidixic acid, ciprofloxacin, cephalothin and trimethoprim-sulfamethoxazole (82%, 78%, 62% and 59%, respectively) were observed. Fourteen distinct patterns were identified for the virulence determinants such as afaBC, cnfI, fimH, hylA, papEF and sfaDE. The toxin gene, cnfI (75.3%), was the second most prevalent marker to the adhesin, fimH (97.1%). The significant association of sfaDE/hylA (P < 0.01) among antimicrobial resistant and susceptible strains was also observed notwithstanding an overall greater occurrence of virulence factors among the latter. This study provides a snapshot of UPEC complexity in Jamaica and highlights the significant clonal heterogeneity among strains. Such outcomes emphasise the need for evidence-based strategies in the effective management and control of UTIs.
Recombinant Escherichia coli Trx-JZTX-III represses the proliferation of mouse hepatocellular carcinoma cells through induction of cell cycle arrest.

Science.gov (United States)

Sun, Mei-Na; Zhao, Xue-Jiao; Zhao, Han-Dong; Zhang, Wei-Guang; Li, Feng-Lan; Chen, Ming-Zi; Li, Hui; Li, Guangchao

2013-06-01

The aim of the present study was to investigate the effects of recombinant Escherichia coli (E. coli) Trx-jingzhaotoxin (JZTX)-III on cell growth in the mouse hepatocellular carcinoma (HCC) cell line Hepa1-6. The JZTX-III gene sequence was synthesized and cloned into the pET-32a(+) vector to construct the recombinant fusion protein Trx-JZTX-III, which was subsequently purified. Hepa1-6 cells were treated with 0 to 1,000-µg/ml concentrations of Trx-JZTX-III; this was demonstrated to affect cell viability, as determined by the 3-(4,5-dimethylthiazol‑2-yl)-2,5-diphenyltetra-zolium bromide (MTT) assay. The expression of the proliferating cell nuclear antigen (PCNA) protein was investigated using western blot analysis. A colony formation assay was used to determine Hepa1-6 cell proliferation, and the migration ability of cells was determined using a wound‑healing assay. Additionally, flow cytometry was employed to observe changes in the cell cycle. The MTT assay and quantification of PCNA expression indicated that recombinant E. coli Trx-JZTX-III significantly repressed the proliferation of Hepa1-6 cells. Colony formation and the migration of malignant cells was inhibited following treatment with recombinant E. coli Trx-JZTX-III. Flow cytometry showed that recombinant E. coli Trx-JZTX-III induced G0/G1 cell cycle arrest. In conclusion, recombinant E. coli Trx-JZTX-III functions as a tumor suppressor drug in mouse HCC and its underlying mechanism may involve the induction of G0/G1 cell cycle arrest.
Escherichia coli lipoprotein binds human plasminogen via an intramolecular domain

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Tammy eGonzalez

2015-10-01

Full Text Available Escherichia coli lipoprotein (Lpp is a major cellular component that exists in two distinct states, bound-form and free-form. Bound-form Lpp is known to interact with the periplasmic bacterial cell wall, while free-form Lpp is localized to the bacterial cell surface. A function for surface-exposed Lpp has yet to be determined. We hypothesized that the presence of C-terminal lysines in the surface-exposed region of Lpp would facilitate binding to the host zymogen plasminogen, a protease commandeered by a number of clinically important bacteria. Recombinant Lpp was synthesized and the binding of Lpp to plasminogen, the effect of various inhibitors on this binding, and the effects of various mutations of Lpp on Lpp-plasminogen interactions were examined. Additionally, the ability of Lpp-bound plasminogen to be converted to active plasmin was analyzed. We determined that Lpp binds plasminogen via an atypical domain located near the center of mature Lpp that may not be exposed on the surface of intact E. coli according to the current localization model. Finally, we found that plasminogen bound by Lpp can be converted to active plasmin. While the consequences of Lpp binding plasminogen are unclear, these results prompt further investigation of the ability of surface exposed Lpp to interact with host molecules such as extracellular matrix components and complement regulators, and the role of these interactions in infections caused by E. coli and other bacteria.
Integrons in Escherichia coli from food-producing animals in The Netherlands

NARCIS (Netherlands)

Box, A.T.; Mevius, D.J.; Schellen, P.; Verhoef, J.; Fluit, A.C.

2005-01-01

The presence and character of class 1 integrons in multidrug-resistant Escherichia coli from slaughter animals and meat was determined by integrase-specific PCR and conserved segment PCR-restriction fragment length polymorphism (RFLP). At least five different class 1 integron types were found and
FTIR nanobiosensors for Escherichia coli detection

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Stefania Mura

2012-07-01

Full Text Available Infections due to enterohaemorrhagic E. coli (Escherichia coli have a low incidence but can have severe and sometimes fatal health consequences, and thus represent some of the most serious diseases due to the contamination of water and food. New, fast and simple devices that monitor these pathogens are necessary to improve the safety of our food supply chain. In this work we report on mesoporous titania thin-film substrates as sensors to detect E. coli O157:H7. Titania films treated with APTES ((3-aminopropyltriethoxysilane and GA (glutaraldehyde were functionalized with specific antibodies and the absorption properties monitored. The film-based biosensors showed a detection limit for E. coli of 1 × 102 CFU/mL, constituting a simple and selective method for the effective screening of water samples.
High susceptibility prevalence for F4+ and F18+Escherichia coli in Flemish pigs.

Science.gov (United States)

Nguyen, Ut V; Coddens, Annelies; Melkebeek, Vesna; Devriendt, Bert; Goetstouwers, Tiphanie; Poucke, Mario Van; Peelman, Luc; Cox, Eric

2017-04-01

F4 and/or F18 enterotoxigenic Escherichia coli (F4 + /F18 + ETEC) are responsible for diarrhea while F18 + verotoxigenic E. coli (F18 + VTEC) cause edema disease in pigs. Both infections can result in severe economic losses, which are mainly the result of the medication, growth retardation and mortality. The susceptibility of piglets to these pathogens is determined by the presence of F4 and F18 receptors (F4R and F18R). Understanding the composition of the susceptibility phenotypes of pigs is useful for animal health and breeding management. This study aimed to determine the prevalence of the F4 ETEC susceptibility phenotypes and F18 + E. coli susceptibility among Flemish pig breeds by using the in vitro villous adhesion assay. In this study, seven F4 ETEC susceptibility phenotypes were found, namely A (F4 ab R + , ac R + , ad R + ; 59.16%), B (F4 ab R + , ac R + , ad R - ; 6.28%), C (F4 ab R + , ac R - , ad R + ; 2.62%), D (F4 ab R - , ac R - , ad R + ; 6.28%), E (F4 ab R - , ac R - , ad R - ; 24.08%), F (F4 ab R + , ac R - , ad R - ; 1.05%) and G (F4 ab R - , ac R + , ad R - ; 0.52%). F4ab and F4ac E. coli showed a stronger degree of adhesion to the intestinal villi (53.40% and 52.88% strong adhesion, respectively), compared to F4ad E. coli (43.46% strong adhesion). Furthermore, the correlation between F4ac and F4ab adhesion was higher (r=0.78) than between F4ac and F4ad adhesion (r=0.41) and between F4ab and F4ad adhesion (r=0.57). For F18 + E. coli susceptibility, seven out of 82 pigs were F18R negative (8.54%), but only two of these seven pigs (2.44%) were also negative for F4R. As such, the chance to identify a pig that is positive for a F4 ETEC variant or F18 + E. coli is 97.56%. Therefore, significant economic losses will arise due to F4 + and/or F18 + E. coli infections in the Flemish pig population due to the high susceptibility prevalence. Copyright © 2016 Elsevier B.V. All rights reserved.
IncF Plasmids Are Commonly Carried by Antibiotic Resistant Escherichia coli Isolated from Drinking Water Sources in Northern Tanzania

OpenAIRE

Lyimo, Beatus; Buza, Joram; Subbiah, Murugan; Temba, Sylivester; Kipasika, Honest; Smith, Woutrina; Call, Douglas R.

2016-01-01

The aim of this study was to identify the replicon types of plasmids, conjugation efficiencies, and the complement of antibiotic resistance genes for a panel of multidrug resistant E. coli isolates from surface waters in northern Tanzania. Standard membrane filtration was used to isolate and uidA PCR was used to confirm the identity of strains as E. coli. Antibiotic susceptibility was determined by breakpoint assay and plasmid conjugation was determined by filter-mating experiments. PCR and s...

Bacteraemia Caused by Escherichia Coli in Cancer Patients at a Specialist Center in Pakistan

International Nuclear Information System (INIS)

Parveen, A.; Sultan, F.; Saleem, S.; Nazeer, S. H.; Raza, A.; Zafar, W.; Nizamuddin, S.; Mahboob, A.

2015-01-01

Objective: To analyse the antimicrobial susceptibility patterns of Escherichia coli bacteraemia among cancer patients, and to assess the risk factors and outcomes of multidrug-resistant Escherichia coli bacteraemia. Methods: The retrospective study was conducted at Shaukat Khanum Memorial Cancer Hospital and Research Centre, Lahore, and comprised medical records of patients with Escherichia coli bacteraemia presenting between December 2012 and November 2013. Multivariable logistic regression analyses were used to determine the factors associated with the development and 30-day mortality of multidrug-resistant Escherichia coli bacteraemia. Results: Out of 1603 episodes of bacteraemia, 227(35.6 percent) were caused by E.coli, of which 98(43.2 percent) were multidrug-resistant. In multivariable analysis, age less than 18 years (adjusted odds ratio 3.92; 95 percent confidence interval 1.43-10.68), presence of central venous catheter (adjusted odds ratio 2.12; 95 percent confidence interval 1.04-4.33) and exposure to piperacillin/tazobactam within 90 days prior to infection (adjusted odds ratio 2.37; 95 percent confidence interval 1.15-4.86) were identified as independent risk factors for acquisition of multidrug-resistant Escherichia coli bacteraemia. The overall 30 day mortality rate was 35.2 percent (80/227). Risk factors for mortality were intensive care unit admission (adjusted odds ratio 3.95; 95 percent confidence interval 1.79-8.71) and profound neutropenia (adjusted odds ratio 4.03; 95 percent confidence interval 1.55-10.49). Conclusion: Bloodstream infections with multidrug-resistant Escherichia coli were common in cancer patients. However it was not a predictor of mortality. (author)
Volunteer Challenge With Enterotoxigenic Escherichia coli That Express Intestinal Colonization Factor Fimbriae CS17 and CS19

Science.gov (United States)

2011-07-01

Serotype was determined by classic serological methods at the Universidad Nacional Aut6noma de Mexico [UNAMl. H- indrcates non-motility. b CF...Levine MM, Merson MM. Serologic differentiation between antitoxin responses to infection with Vibrio cholerae and enterotoxin-producing Escherichia coli...prototype cholera B subunit-colonization factor antigen cnterotoxigenic Escherichia coli vaccine. Vaccine 1993; 1[:929-34. 15. Levine MM, Nalin DR
Growth of Escherichia coli O157:H7, Non-O157 Shiga Toxin-Producing Escherichia coli , and Salmonella in Water and Hydroponic Fertilizer Solutions.

Science.gov (United States)

Shaw, Angela; Helterbran, Kara; Evans, Michael R; Currey, Christopher

2016-12-01

The desire for local, fresh produce year round is driving the growth of hydroponic growing systems in the United States. Many food crops, such as leafy greens and culinary herbs, grown within hydroponics systems have their root systems submerged in recirculating nutrient-dense fertilizer solutions from planting through harvest. If a foodborne pathogen were introduced into this water system, the risk of contamination to the entire crop would be high. Hence, this study was designed to determine whether Escherichia coli O157:H7, non-O157 Shiga toxin-producing E. coli , and Salmonella were able to survive and reproduce in two common hydroponic fertilizer solutions and in water or whether the bacteria would be killed or suppressed by the fertilizer solutions. All the pathogens grew by 1 to 6 log CFU/ml over a 24-h period, depending on the solution. E. coli O157:H7 reached higher levels in the fertilizer solution with plants (3.12 log CFU/ml), whereas non-O157 Shiga toxin-producing E. coli and Salmonella reached higher levels in the fertilizer solution without plants (1.36 to 3.77 log CFU/ml). The foodborne pathogens evaluated here survived for 24 h in the fertilizer solution, and populations grew more rapidly in these solutions than in plain water. Therefore, human pathogens entering the fertilizer solution tanks in hydroponic systems would be expected to rapidly propagate and spread throughout the system and potentially contaminate the entire crop.
Inhibition of Inducible Nitric Oxide Controls Pathogen Load and Brain Damage by Enhancing Phagocytosis of Escherichia coli K1 in Neonatal Meningitis

OpenAIRE

Mittal, Rahul; Gonzalez-Gomez, Ignacio; Goth, Kerstin A.; Prasadarao, Nemani V.

2010-01-01

Escherichia coli K1 is a leading cause of neonatal meningitis in humans. In this study, we sought to determine the pathophysiologic relevance of inducible nitric oxide (iNOS) in experimental E. coli K1 meningitis. By using a newborn mouse model of meningitis, we demonstrate that E. coli infection triggered the expression of iNOS in the brains of mice. Additionally, iNOS−/− mice were resistant to E. coli K1 infection, displaying normal brain histology, no bacteremia, no disruption of the blood...
Escherichia coli Probiotic Strain ED1a in Pigs Has a Limited Impact on the Gut Carriage of Extended-Spectrum-β-Lactamase-Producing E. coli

Science.gov (United States)

Mourand, G.; Paboeuf, F.; Fleury, M. A.; Jouy, E.; Bougeard, S.; Denamur, E.

2016-01-01

ABSTRACT Four trials were conducted to evaluate the impact of Escherichia coli probiotic strain ED1a administration to pigs on the gut carriage or survival in manure of extended-spectrum-β-lactamase-producing E. coli. Groups of pigs were orally inoculated with strain E. coli M63 carrying the blaCTX-M-1 gene (n = 84) or used as a control (n = 26). In the first two trials, 24 of 40 E. coli M63-inoculated pigs were given E. coli ED1a orally for 6 days starting 8 days after oral inoculation. In the third trial, 10 E. coli M63-inoculated pigs were given either E. coli ED1a or probiotic E. coli Nissle 1917 for 5 days. In the fourth trial, E. coli ED1a was given to a sow and its 12 piglets, and these 12 piglets plus 12 piglets that had not received E. coli ED1a were then inoculated with E. coli M63. Fecal shedding of cefotaxime-resistant Enterobacteriaceae (CTX-RE) was studied by culture, and blaCTX-M-1 genes were quantified by PCR. The persistence of CTX-RE in manure samples from inoculated pigs or manure samples inoculated in vitro with E. coli M63 with or without probiotics was studied. The results showed that E. coli M63 and ED1a were good gut colonizers. The reduction in the level of fecal excretion of CTX-RE in E. coli ED1a-treated pigs compared to that in nontreated pigs was usually less than 1 log10 CFU and was mainly observed during the probiotic administration period. The results obtained with E. coli Nissle 1917 did not differ significantly from those obtained with E. coli ED1a. CTX-RE survival did not differ significantly in manure samples with or without probiotic treatment. In conclusion, under our experimental conditions, E. coli ED1a and E. coli Nissle 1917 could not durably prevent CTX-RE colonization of the pig gut. PMID:27795372
Escherichia coli Probiotic Strain ED1a in Pigs Has a Limited Impact on the Gut Carriage of Extended-Spectrum-β-Lactamase-Producing E. coli.

Science.gov (United States)

Mourand, G; Paboeuf, F; Fleury, M A; Jouy, E; Bougeard, S; Denamur, E; Kempf, I

2017-01-01

Four trials were conducted to evaluate the impact of Escherichia coli probiotic strain ED1a administration to pigs on the gut carriage or survival in manure of extended-spectrum-β-lactamase-producing E. coli Groups of pigs were orally inoculated with strain E. coli M63 carrying the bla CTX-M-1 gene (n = 84) or used as a control (n = 26). In the first two trials, 24 of 40 E. coli M63-inoculated pigs were given E. coli ED1a orally for 6 days starting 8 days after oral inoculation. In the third trial, 10 E. coli M63-inoculated pigs were given either E. coli ED1a or probiotic E. coli Nissle 1917 for 5 days. In the fourth trial, E. coli ED1a was given to a sow and its 12 piglets, and these 12 piglets plus 12 piglets that had not received E. coli ED1a were then inoculated with E. coli M63. Fecal shedding of cefotaxime-resistant Enterobacteriaceae (CTX-RE) was studied by culture, and bla CTX-M-1 genes were quantified by PCR. The persistence of CTX-RE in manure samples from inoculated pigs or manure samples inoculated in vitro with E. coli M63 with or without probiotics was studied. The results showed that E. coli M63 and ED1a were good gut colonizers. The reduction in the level of fecal excretion of CTX-RE in E. coli ED1a-treated pigs compared to that in nontreated pigs was usually less than 1 log 10 CFU and was mainly observed during the probiotic administration period. The results obtained with E. coli Nissle 1917 did not differ significantly from those obtained with E. coli ED1a. CTX-RE survival did not differ significantly in manure samples with or without probiotic treatment. In conclusion, under our experimental conditions, E. coli ED1a and E. coli Nissle 1917 could not durably prevent CTX-RE colonization of the pig gut. Copyright © 2016 American Society for Microbiology.
Occurrence of weak mutators among avian pathogenic Escherichia coli (APEC) isolates causing salpingitis and peritonitis in broiler breeders

DEFF Research Database (Denmark)

Pires dos Santos, Teresa M S; Bisgaard, Magne; Kyvsgaard, Niels Christian

2014-01-01

A collection of 46 avian pathogenic Escherichia coli (APEC) isolates was examined for the presence of mutators by determining the rate of mutation to rifampicin resistance. The collection included 34 E. coli isolates obtained in pure culture from chronic lesions of salpingitis and peritonitis in 34...... broiler breeders, of which 12 were associated with the development of secondary septicemia. Twelve additional isolates were obtained from a clonal outbreak (ST95) of E. coli peritonitis syndrome (EPS), the lesions of which changed gradually over time into a subacute/chronic form. The hypothesis...
Comparative analysis of antibiotic resistance and phylogenetic group patterns in human and porcine urinary tract infectious Escherichia coli

DEFF Research Database (Denmark)

Hancock, Viktoria; Nielsen, E.M.; Krag, L.

2009-01-01

Urinary tract infections (UTIs) are one of the most common infectious diseases in humans and domestic animals such as pigs. The most frequent infectious agent in such infections is Escherichia coli. Virulence characteristics of E. coli UTI strains range from highly virulent pyelonephritis strains...... to relatively benign asymptomatic bacteriuria strains. Here we analyse a spectrum of porcine and human UTI E. coli strains with respect to their antibiotic resistance patterns and their phylogenetic groups, determined by multiplex PCR. The clonal profiles of the strains differed profoundly; whereas human...
N-type Cu2O Film for Photocatalytic and Photoelectrocatalytic Processes: Its stability and Inactivation of E. coli

International Nuclear Information System (INIS)

Xiong, Liangbin; Ng, Tsz Wai; Yu, Ying; Xia, Dehua; Yip, Ho Yin; Li, Guiying; An, Taicheng; Zhao, Huijun; Wong, Po Keung

2015-01-01

Highlights: • Photoelectrocatalytic inactivation of E. coli by Cu 2 O film was firstly reported. • 7 log of E. coli could be completely inactivated in 2 h by Cu 2 O with a 0.1 V bias. • Charge transfer between Cu 2 O and E. coli was monitored by electrochemical technique. • Inactivation of E. coli by electric charges of electrodes was in-depth investigated. • Stability of N-type Cu 2 O as a photocatalyst was studied for the first time. - ABSTRACT: Photoelectrocatalytic (PEC) inactivation of Escherichia coli K-12 by cuprous oxide (Cu 2 O) film irradiated by visible light is firstly reported. A complete inactivation of about 7 log of E. coli was obtained for Cu 2 O film within 6 h. The bacterial inactivation efficiency was significantly improved in a photoelectrochemical cell, in which 7 log of E. coli could be completely inactivated within 2 h by Cu 2 O film with a 0.1 V bias. Electric charge transfer between electrodes and E. coli, and electric charge inactivation towards E. coli were investigated using membrane-separated reactor combined with short circuit photocurrent technique. H 2 O 2 , hole, and toxicity of Cu 2 O film were found responsible for the inactivation of E. coli. Toxicity of copper ions (including Cu 2+ and Cu + ) leakage from Cu 2 O films was determined and the results showed that the amount of leakage copper ions was not toxic to E. coli. Finally, the Cu 2 O film was proved to be effective and reusable for PC and PEC inactivation of E. coli
The Intriguing Evolutionary Journey of Enteroinvasive E. coli (EIEC) toward Pathogenicity.

Science.gov (United States)

Pasqua, Martina; Michelacci, Valeria; Di Martino, Maria Letizia; Tozzoli, Rosangela; Grossi, Milena; Colonna, Bianca; Morabito, Stefano; Prosseda, Gianni

2017-01-01

Among the intestinal pathogenic Escherichia coli , enteroinvasive E. coli (EIEC) are a group of intracellular pathogens able to enter epithelial cells of colon, multiplicate within them, and move between adjacent cells with a mechanism similar to Shigella , the ethiological agent of bacillary dysentery. Despite EIEC belong to the same pathotype of Shigella , they neither have the full set of traits that define Shigella nor have undergone the extensive gene decay observed in Shigella . Molecular analysis confirms that EIEC are widely distributed among E. coli phylogenetic groups and correspond to bioserotypes found in many E. coli serogroups. Like Shigella , also in EIEC the critical event toward a pathogenic life-style consisted in the acquisition by horizontal gene transfer of a large F-type plasmid (pINV) containing the genes required for invasion, intracellular survival, and spreading through the intestinal mucosa. In Shigella , the ample gain in virulence determinants has been counteracted by a substantial loss of functions that, although important for the survival in the environment, are redundant or deleterious for the life inside the host. The pathoadaptation process that has led Shigella to modify its metabolic profile and increase its pathogenic potential is still in infancy in EIEC, although maintenance of some features typical of E. coli might favor their emerging relevance as intestinal pathogens worldwide, as documented by recent outbreaks in industrialized countries. In this review, we will discuss the evolution of EIEC toward Shigella -like invasive forms going through the epidemiology, including the emergence of new virulent strains, their genome organization, and the complex interactions they establish with the host.
Emissions of Escherichia coli Carrying Extended-Spectrum β-Lactamase Resistance from Pig Farms to the Surrounding Environment

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Lili Gao

2015-04-01

Full Text Available The dissemination of extended-spectrum β-lactamase (ESBL-producing Escherichia coli (E. coli from food-producing animals to the surrounding environment has attracted much attention. To determine the emissions of ESBL-producing E. coli from pig farms to the surrounding environment, fecal and environmental samples from six pig farms were collected. In total, 119 ESBL-producing E. coli were isolated from feces, air samples, water, sludge and soil samples. Antibiotic susceptibility testing showed that the ESBL-producing isolates were resistant to multiple antibiotics and isolates of different origin within the same farm showed similar resistance phenotypes. Both CTX-M and TEM ESBL-encoding genes were detected in these isolates. CTX-M-14 and CTX-M-15 were the predominant ESBL genes identified. ESBL producers from feces and environmental samples within the same farm carried similar CTX-M types. The results indicated that the ESBL-producing E. coli carrying multidrug resistance could readily disseminate to the surrounding environment.
ANTIMICROBIAL DRUG RESISTANCE IN STRAINS OF Escherichia coli ISOLATED FROM FOOD SOURCES

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Mohammed Uddin Rasheed

2014-07-01

Full Text Available A variety of foods and environmental sources harbor bacteria that are resistant to one or more antimicrobial drugs used in medicine and agriculture. Antibiotic resistance in Escherichia coli is of particular concern because it is the most common Gram-negative pathogen in humans. Hence this study was conducted to determine the antibiotic sensitivity pattern of E. coli isolated from different types of food items collected randomly from twelve localities of Hyderabad, India. A total of 150 samples comprising; vegetable salad, raw egg-surface, raw chicken, unpasteurized milk, and raw meat were processed microbiologically to isolate E. coli and to study their antibiotic susceptibility pattern by the Kirby-Bauer method. The highest percentages of drug resistance in isolates of E. coli were detected from raw chicken (23.3% followed by vegetable salad (20%, raw meat (13.3%, raw egg-surface (10% and unpasteurized milk (6.7%. The overall incidence of drug resistant E. coli was 14.7%. A total of six (4% Extended Spectrum β-Lactamase (ESBL producers were detected, two each from vegetable salads and raw chicken, and one each from raw egg-surface and raw meat. Multidrug resistant strains of E. coli are a matter of concern as resistance genes are easily transferable to other strains. Pathogen cycling through food is very common and might pose a potential health risk to the consumer. Therefore, in order to avoid this, good hygienic practices are necessary in the abattoirs to prevent contamination of cattle and poultry products with intestinal content as well as forbidding the use of untreated sewage in irrigating vegetables.
Survival of Escherichia coli on Lettuce under Field Conditions Encountered in the Northeastern United States.

Science.gov (United States)

Weller, Daniel L; Kovac, Jasna; Roof, Sherry; Kent, David J; Tokman, Jeffrey I; Kowalcyk, Barbara; Oryang, David; Ivanek, Renata; Aceituno, Anna; Sroka, Christopher; Wiedmann, Martin

2017-07-01

Although wildlife intrusion and untreated manure have been associated with microbial contamination of produce, relatively few studies have examined the survival of Escherichia coli on produce under field conditions following contamination (e.g., via splash from wildlife feces). This experimental study was performed to estimate the die-off rate of E. coli on preharvest lettuce following contamination with a fecal slurry. During August 2015, field-grown lettuce was inoculated via pipette with a fecal slurry that was spiked with a three-strain cocktail of rifampin-resistant nonpathogenic E. coli. Ten lettuce heads were harvested at each of 13 time points following inoculation (0, 2.5, 5, and 24 h after inoculation and every 24 h thereafter until day 10). The most probable number (MPN) of E. coli on each lettuce head was determined, and die-off rates were estimated. The relationship between sample time and the log MPN of E. coli per head was modeled using a segmented linear model. This model had a breakpoint at 106 h (95% confidence interval = 69, 142 h) after inoculation, with a daily decrease of 0.70 and 0.19 log MPN for 0 to 106 h and 106 to 240 h following inoculation, respectively. These findings are consistent with die-off rates obtained in similar studies that assessed E. coli survival on produce following irrigation. Overall, these findings provide die-off rates for E. coli on lettuce that can be used in future quantitative risk assessments.
Risk of Transmission of Antimicrobial Resistant Escherichia coli from Commercial Broiler and Free-Range Retail Chicken in India

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Arif Hussain

2017-11-01

Full Text Available Multidrug-resistant Escherichia coli infections are a growing public health concern. This study analyzed the possibility of contamination of commercial poultry meat (broiler and free-range with pathogenic and or multi-resistant E. coli in retail chain poultry meat markets in India. We analyzed 168 E. coli isolates from broiler and free-range retail poultry (meat/ceca sampled over a wide geographical area, for their antimicrobial sensitivity, phylogenetic groupings, virulence determinants, extended-spectrum-β-lactamase (ESBL genotypes, fingerprinting by Enterobacterial Repetitive Intergenic Consensus (ERIC PCR and genetic relatedness to human pathogenic E. coli using whole genome sequencing (WGS. The prevalence rates of ESBL producing E. coli among broiler chicken were: meat 46%; ceca 40%. Whereas, those for free range chicken were: meat 15%; ceca 30%. E. coli from broiler and free-range chicken exhibited varied prevalence rates for multi-drug resistance (meat 68%; ceca 64% and meat 8%; ceca 26%, respectively and extraintestinal pathogenic E. coli (ExPEC contamination (5 and 0%, respectively. WGS analysis confirmed two globally emergent human pathogenic lineages of E. coli, namely the ST131 (H30-Rx subclone and ST117 among our poultry E. coli isolates. These results suggest that commercial poultry meat is not only an indirect public health risk by being a possible carrier of non-pathogenic multi-drug resistant (MDR-E. coli, but could as well be the carrier of human E. coli pathotypes. Further, the free-range chicken appears to carry low risk of contamination with antimicrobial resistant and extraintestinal pathogenic E. coli (ExPEC. Overall, these observations reinforce the understanding that poultry meat in the retail chain could possibly be contaminated by MDR and/or pathogenic E. coli.
Enhanced target-specific signal detection using an Escherichia coli lysate in multiplex microbead immunoassays with E. coli-derived recombinant antigens.

Science.gov (United States)

Crestani, Sandra; Leitolis, Amanda; Lima, Lucianna Freitas Oliveira; Krieger, Marco A; Foti, Leonardo

2016-08-01

Diverse techniques have been developed to analyze antibody-mediated responses to infections. However, the most common tests, i.e., enzyme-linked immunosorbent assays, require separate reactions for each antigen and consequently necessitate large sample volumes. Luminex technology allows the detection of multiple antibodies in a single experiment, but nonspecific binding can impair the results. Therefore, we examined the use of Escherichia coli lysates to reduce nonspecific binding and improve the results of liquid microarrays based on Luminex technology. Anti-bacteria antibodies were detected in human serum samples, as evidenced by high median fluorescence intensity (MFI) in assays performed with paramagnetic microspheres coupled with E. coli lysates. Moreover, the addition of an E. coli lysate as a blocker reduced the nonspecific binding of antigens produced by E. coli in a concentration-dependent manner. Tris-HCl reduced MFI values in negative samples, but did not affect MFI for positive samples. For microspheres coupled with different antigens, an E. coli lysate blocker significantly improved the fluorescence signals from positive samples. The addition of Tris-HCl and the E. coli lysate induced antigen-specific differences in MFI. This combination of the E. coli lysate blocker and Tris-HCl yielded a statistically significant improvement in MFI in the assays for Chagas disease and hepatitis C virus samples. However, for the Treponema pallidum p47 antigen improvement in MFI was only observed for the preparation with the E. coli blocker at a concentration of 3%. In conclusion, the addition of an E. coli lysate and Tris-HCl to the microarray assay reduced the nonspecific binding of human anti-bacteria antibodies and, therefore, increased the specific MFI. Copyright © 2016 Elsevier B.V. All rights reserved.
Lactobacillus rhamnosus GG supernatant enhance neonatal resistance to systemic Escherichia coli K1 infection by accelerating development of intestinal defense

OpenAIRE

Xiaolong He; Qing Zeng; Santhosh Puthiyakunnon; Zhijie Zeng; Weijun Yang; Jiawen Qiu; Lei Du; Swapna Boddu; Tongwei Wu; Danxian Cai; Sheng-He Huang; Hong Cao

2017-01-01

The objective of this study was to determine whether Lactobacillus rhamnosus GG culture supernatant (LCS) has a preventive effect against gut-derived systemic neonatal Escherichia coli (E. coli) K1 infection. The preventive effects were evaluated in human colonic carcinoma cell line Caco-2 and neonatal rat models. Our in vitro results showed that LCS could block adhesion, invasion and translocation of E. coli K1 to Caco-2 monolayer via up-regulating mucin production and maintaining intestinal...
Variability in the characterization of total coliforms, fecal coliforms, and escherichia coli in recreational water supplies of North Mississippi, USA

Science.gov (United States)

The fecal coliform, Escherichia coli, is a historical organism for the detection of fecal pollution in water supplies. The presence of E. coli indicates a potential contamination of the water supply by other more hazardous human pathogens. In order to accurately determine the presence and degree o...
Antimicrobial resistant Salmonella enterica and Escherichia coli recovered from dairy operations

Science.gov (United States)

Antimicrobial resistance has become a major public health concern and animal agriculture is often implicated as a source of resistant bacteria. The primary objective of this study was to determine prevalence of antimicrobial resistance in Salmonella and E. coli from healthy animals on dairy farms i...
Profiling of Escherichia coli Chromosome database.

Science.gov (United States)

Yamazaki, Yukiko; Niki, Hironori; Kato, Jun-ichi

2008-01-01

The Profiling of Escherichia coli Chromosome (PEC) database (http://www.shigen.nig.ac.jp/ecoli/pec/) is designed to allow E. coli researchers to efficiently access information from functional genomics studies. The database contains two principal types of data: gene essentiality and a large collection of E. coli genetic research resources. The essentiality data are based on data compilation from published single-gene essentiality studies and on cell growth studies of large-deletion mutants. Using the circular and linear viewers for both whole genomes and the minimal genome, users can not only gain an overview of the genome structure but also retrieve information on contigs, gene products, mutants, deletions, and so forth. In particular, genome-wide exhaustive mutants are an essential resource for studying E. coli gene functions. Although the genomic database was constructed independently from the genetic resources database, users may seamlessly access both types of data. In addition to these data, the PEC database also provides a summary of homologous genes of other bacterial genomes and of protein structure information, with a comprehensive interface. The PEC is thus a convenient and useful platform for contemporary E. coli researchers.
Evaluation of Petrifilm™ Select E. coli Count Plate medium to discriminate antimicrobial resistant Escherichia coli

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Jensen Lars

2008-09-01

Full Text Available Abstract Background Screening and enumeration of antimicrobial resistant Escherichia coli directly from samples is needed to identify emerging resistant clones and obtain quantitative data for risk assessment. Aim of this study was to evaluate the performance of 3M™ Petrifilm™ Select E. coli Count Plate (SEC plate supplemented with antimicrobials to discriminate antimicrobial-resistant and non-resistant E. coli. Method A range of E. coli isolates were tested by agar dilution method comparing the Minimal Inhibitory Concentration (MIC for eight antimicrobials obtained by Mueller-Hinton II agar, MacConkey agar and SEC plates. Kappa statistics was used to assess the levels of agreement when classifying strains as resistant, intermediate or susceptible. Results SEC plate showed that 74% of all strains agreed within ± 1 log2 dilution when comparing MICs with Mueller-Hinton II media. High agreement levels were found for gentamicin, ampicillin, chloramphenicol and cefotaxime, resulting in a kappa value of 0.9 and 100% agreement within ± 1 log2 dilution. Significant variances were observed for oxytetracycline and sulphamethoxazole. Further tests showed that the observed discrepancy in classification of susceptibility to oxytetracycline by the two media could be overcome when a plate-dependent breakpoint of 64 mg/L was used for SEC plates. For sulphamethoxazole, SEC plates provided unacceptably high MICs. Conclusion SEC plates showed good agreement with Mueller-Hinton II agar in MIC studies and can be used to screen and discriminate resistant E. coli for ampicillin, cephalothin, streptomycin, chloramphenicol, cefotaxime and gentamicin using CLSI standardized breakpoints, but not for sulphamethoxazole. SEC plates can also be used to discriminate oxytetracycline-resistant E. coli if a plate-dependent breakpoint value of 64 mg/L is used.

Inactivation of Escherichia coli in soil by solarization

International Nuclear Information System (INIS)

Wu, S.; Nishihara, M.; Kawasaki, Y.; Yokoyama, A.; Matsuura, K.; Koga, T.; Ueno, D.; Inoue, K.; Someya, T.

2009-01-01

Contamination of agricultural soil by fecal pathogenic bacteria poses a potential risk of infection to humans. For the biosafety control of field soil, soil solarization in an upland field was examined to determine the efficiency of solarization on the inactivation of Escherichia coli inoculated into soil as a model microorganism for human pathogenic bacteria. Soil solarization, carried out by sprinkling water and covering the soil surface with thin plastic sheets, greatly increased the soil temperature. The daily average temperature of the solarized soil was 4–10°C higher than that of the non-solarized soil and fluctuated between 31 and 38°C. The daily highest temperature reached more than 40°C for 8 days in total in the solarized soil during the second and third weeks of the experiment. Escherichia coli in the solarized soil became undetectable (< 0.08 c.f.u. g −1 dry soil) within 4 weeks as a result, whereas E. coli survived for more than 6 weeks in the non-solarized soil. Soil solarization, however, had little influence on the total direct count and total viable count of bacteria in the soil. These results indicate that soil solarization would be useful for the biosafety control of soil contaminated by human pathogens via immature compost or animal feces. (author)
Prevalence and antibiotic profile of Escherichia coli in traditionally made ice cream in retails of Khoy

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H Molaabaszadeh

2012-08-01

Full Text Available Escherichia coli is among the most important intestinal foodborne bacterial pathogens. The objective of this study was to estimate the prevalence of E. coli in traditionally-made ice creams at retails of Khoy city. Moreover, the antibiotic profile of the isolates was investigated. For this, during April to September 2012, 150 ice cream samples collected from markets and confectionery shops. The samples were analyzed for the presence of E. coli. Afterwards, the antibiotic susceptibility and resistance of the isolates was evaluated on 10 different antibiotic using Kirby-Bauer test.According tothe results, 31.33% (47.150 of the samples were found positive for E. coli. The results of antibiogram test indicated that the highest level of sensitivity was determined for ceftizoxim (80.85%, ciprofloxacin (78.73%, and ceftriaxone (74.47%, respectively. In contrast, the most resistance antibiotics were amoxicillin (95.74%, oxacilin (82.98%, kanamycin (61.7%, respectively. The results revealed that the prevalence of E. coli, as the indication of fecal contamination, in traditionally made ice cream in Khoy retails and the antibiotic profile of the isolates were noticeable.
Infectious endocarditis caused by Escherichia coli

DEFF Research Database (Denmark)

Lauridsen, Trine Kiilerich; Arpi, Magnus; Fritz-Hansen, Thomas

2011-01-01

Although Escherichia coli is among the most common causes of Gram-negative bacteraemia, infectious endocarditis (IE) due to this pathogen is rare. A 67-y-old male without a previous medical history presented with a new mitral regurgitation murmur and persisting E. coli bacteraemia in spite of broad......-spectrum intravenous antibiotics. Transthoracic and transoesophageal echocardiography revealed a severe mitral endocarditis. E. coli DNA was identified from the mitral valve and the vegetation, and no other pathogen was found. The case was further complicated by spondylodiscitis and bilateral endophthalmitis. Extra......-intestinal pathogenic E. coli (ExPEC) are able to colonize tissue outside the gastrointestinal tract and contain a variety of virulence factors that may enable the pathogens to invade and induce infections in the cardiac endothelia. In these cases echocardiography as the imaging technology is of paramount importance...
Occurrence, genotyping, shiga toxin genes and associated risk factors of E. coli isolated from dairy farms, handlers and milk consumers.

Science.gov (United States)

Awadallah, M A; Ahmed, H A; Merwad, A M; Selim, M A

2016-11-01

The objectives of the current study were to determine the occurrence and genotypes of E. coli in dairy farms, workers and milk consumers and to evaluate risk factors associated with contamination of milk in dairy farms. Molecular characterization of shiga toxin associated genes and enterobacterial repetitive intergenic consensus-PCR (ERIC-PCR) finger printing of E. coli from different sources were also studied. Paired milk samples and rectal swabs from 125 dairy cows, rectal swabs from 82 calves and hand swabs from 45 dairy workers from five dairy farms were collected. In addition, 100 stool samples from 70 diarrheic and 30 healthy humans were collected and examined for the presence of E. coli. E. coli was isolated from milk (22.4%), dairy cattle feces (33.6%), calf feces (35.4%), dairy worker hand swabs (11.1%) and stools of milk consumers (2%, from diarrheic patients only). Only stx1 was identified in seven of 12 E. coli O125 isolated from different sources. High genetic diversity was determined (Simpson's index of diversity, D = 1) and E. coli O125 isolates were classified into 12 distinct profiles, E1-E12. The dendrogram analysis showed that two main clusters were generated. Mastitis in dairy cows was considered a risk factor associated with contamination of the produced milk with E. coli. The isolation of E. coli from rectal swabs of dairy cows and calves poses a zoonotic risk through consumption of unpasteurized contaminated dairy milk. Educational awareness should be developed to address risks related to consumption of raw milk. Copyright © 2016 Elsevier Ltd. All rights reserved.
Infectious endocarditis caused by Escherichia coli

DEFF Research Database (Denmark)

Lauridsen, Trine Kiilerich; Arpi, Magnus; Fritz-Hansen, Thomas

2011-01-01

Although Escherichia coli is among the most common causes of Gram-negative bacteraemia, infectious endocarditis (IE) due to this pathogen is rare. A 67-y-old male without a previous medical history presented with a new mitral regurgitation murmur and persisting E. coli bacteraemia in spite of broad......-spectrum intravenous antibiotics. Transthoracic and transoesophageal echocardiography revealed a severe mitral endocarditis. E. coli DNA was identified from the mitral valve and the vegetation, and no other pathogen was found. The case was further complicated by spondylodiscitis and bilateral endophthalmitis. Extra...
Glucose uptake regulation in E. coli by the small RNA SgrS: comparative analysis of E. coli K-12 (JM109 and MG1655 and E. coli B (BL21

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Ng Weng-Ian

2010-09-01

Full Text Available Abstract Background The effect of high glucose concentration on the transcription levels of the small RNA SgrS and the messenger RNA ptsG, (encoding the glucose transporter IICBGlc, was studied in both E. coli K-12 (MG1655 and JM109 and E. coli B (BL21. It is known that the transcription level of sgrS increases when E. coli K-12 (MG1655 and JM109 is exposed to the non-metabolized glucose alpha methyl glucoside (αMG or when the bacteria with a defective glycolysis pathway is grown in presence of glucose. The increased level of sRNA SgrS reduces the level of the ptsG mRNA and consequently lowers the level of the glucose transporter IICBGlc. The suggested trigger for this action is the accumulation of the corresponding phospho-sugars. Results In the course of the described work, it was found that E. coli B (BL21 and E. coli K-12 (JM109 and MG1655 responded similarly to αMG: both strains increased SgrS transcription and reduced ptsG transcription. However, the two strains reacted differently to high glucose concentration (40 g/L. E. coli B (BL21 reacted by increasing sgrS transcription and reducing ptsG transcription while E. coli K-12 (JM109 and MG1655 did not respond to the high glucose concentration, and, therefore, transcription of sgrS was not detected and ptsG mRNA level was not affected. Conclusions The results suggest that E. coli B (BL21 tolerates high glucose concentration not only by its more efficient central carbon metabolism, but also by controlling the glucose transport into the cells regulated by the sRNA SgrS, which may suggest a way to control glucose consumption and increase its efficient utilization.
Loss of DNA-membrane interactions and cessation of DNA synthesis in myeloperoxidase-treated Escherichia coli

International Nuclear Information System (INIS)

Rosen, H.; Orman, J.; Rakita, R.M.; Michel, B.R.; VanDevanter, D.R.

1990-01-01

Neutrophils and monocytes employ a diverse array of antimicrobial effector systems to support their host defense functions. The mechanisms of action of most of these systems are incompletely understood. The present report indicates that microbicidal activity by a neutrophil-derived antimicrobial system, consisting of myeloperoxidase, enzymatically generated hydrogen peroxide, and chloride ion, is accompanied by prompt cessation of DNA synthesis in Escherichia coli, as determined by markedly reduced incorporation of [ 3 H]thymidine into trichloracetic acid-precipitable material. Simultaneously, the myeloperoxidase system mediates a decline in the ability of E. coli membranes to bind hemimethylated DNA sequences containing the E. coli chromosomal origin of replication (oriC). Binding of oriC to the E. coli membrane is an essential element of orderly chromosomal DNA replication. Comparable early changes in DNA synthesis and DNA-membrane interactions were not observed with alternative oxidant or antibiotic-mediated microbicidal systems. It is proposed that oxidants generated by the myeloperoxidase system modify the E. coli membrane in such a fashion that oriC binding is markedly impaired. As a consequence chromosomal DNA replication is impaired and organisms can no longer replicate
Comparative genomic fingerprinting for the subtyping of Campylobacter jejuni and Campylobacter coli biotypes

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Miljković-Selimović Biljana

2017-01-01

Full Text Available Introduction/Objective. Thermophilic campylobacters, especially Campylobacter jejuni (C. jejuni and Campylobacter coli (C. coli, are the most important causes of bacterial diarrhea in developed and developing countries. The disease can occur as a sporadic infection or as large and small outbreaks. Phenotyping and genotyping methods are in use to determine similarities between strains as well their possible common origin. The goal of the study was to compare discriminatory power of biotyping tests and comparative genomic fingerprinting (CGF 40 (100%, as well as a combination of the two tests in detection of clonality or epidemiological relatedness between the studied strains. Methods. We investigated 23 Campylobacter strains using biotyping and CGF typing. Results. We found that biotyping was a more discriminatory method for C. coli, and CGF for C. jejuni strains. In the discrimination of C. jejuni strains, CGF had better discriminatory power [Simpson’s index of diversity (ID was 0.879] over the discrimination of C. coli strains (Simpson’s ID was 0.389. Conclusion. Biotyping and CGF can be complementary methods in detection of similarity, relatedness and possible common origin between strains since the combination of biotyping and CGF methods gives more precise data about diversity within C. coli and C. jejuni strains. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. TR34008
Expression, purification and crystallization of the Cmi immunity protein from Escherichia coli

International Nuclear Information System (INIS)

Römer, Christin; Patzer, Silke I.; Albrecht, Reinhard; Zeth, Kornelius; Braun, Volkmar

2011-01-01

The colicin M immunity protein Cmi protects E. coli cells against killing by colicin M. The Cmi protein was produced for structure determination and crystals were obtained which diffracted to high resolution. Many bacteria kill related bacteria by secretion of bacteriocins. In Escherichia coli, the colicin M protein kills E. coli after uptake into the periplasm. Self-protection from destruction is provided by the co-expressed immunity protein. The colicin M immunity protein (Cmi) was cloned, overexpressed and purified to homogeneity. The correct fold of purified Cmi was analyzed by activity tests and circular-dichroism spectroscopy. Crystallization trials yielded crystals, one of which diffracted to a resolution of 1.9 Å in the orthorhombic space group C222 1 . The crystal packing, with unit-cell parameters a = 66.02, b = 83.47, c = 38.30 Å, indicated the presence of one monomer in the asymmetric unit with a solvent content of 53%
The phenomenon of photoreactivation in bacteria E. coli irradiated by ionizing radiation

International Nuclear Information System (INIS)

Myasnik, M.N.; Morozov, I.I.

1977-01-01

Photoreactivation (PR) has been detected after γ-irradiation of various hypersensitive strains of E. coli. Suspensions of cells were 60 Co γ-irradiated in the dark at room temperature, and either pre- or post-illuminated for 30 minutes with the light from daylight fluorescent lamps. Studies of the effects of PR on the survival curves, and of the photoreactivation kinetics for killing, suggested that the increased survival of the γ-irradiated cells of some strains of E. coli after illumination with photoreactivating light, may be the result of true photoenzymatic repair. Comparison of different strains showed that, after γ-irradiation, PR took place only in those strains of E. coli carrying mutations simultaneously in two genes: uvr,rec or uvr,exr. It therefore seems that mutations in genes uvr,rec or uvr,exr determine both PR ability after γ-irradiation and hypersensitivity to UV-light and γ-rays. Possible mechanisms are discussed. (author)
The Protein Interaction Network of Bacteriophage Lambda with Its Host, Escherichia coli

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Blasche, Sonja; Wuchty, Stefan; Rajagopala, Seesandra V.

2013-01-01

Although most of the 73 open reading frames (ORFs) in bacteriophage λ have been investigated intensively, the function of many genes in host-phage interactions remains poorly understood. Using yeast two-hybrid screens of all lambda ORFs for interactions with its host Escherichia coli, we determined a raw data set of 631 host-phage interactions resulting in a set of 62 high-confidence interactions after multiple rounds of retesting. These links suggest novel regulatory interactions between the E. coli transcriptional network and lambda proteins. Targeted host proteins and genes required for lambda infection are enriched among highly connected proteins, suggesting that bacteriophages resemble interaction patterns of human viruses. Lambda tail proteins interact with both bacterial fimbrial proteins and E. coli proteins homologous to other phage proteins. Lambda appears to dramatically differ from other phages, such as T7, because of its unusually large number of modified and processed proteins, which reduces the number of host-virus interactions detectable by yeast two-hybrid screens. PMID:24049175
Endogenous E. coli endophthalmitis.

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Shammas, H F

1977-01-01

A case of Escherichia coli septicemia with associated metastatic en dophthalmitis and endocarditis is presented. The ocular signs and symptoms were the initial manifestations of sepsis. Irreversible damage to the eye occurred in less than 24 hours. The pattern of metastatic bacterial endophthalmitis has changed since the introduction of potent antimicrobial agents, with an increased incidence of Gram-negative bacillemia. E. coli endophthalmitis carries a poor prognosis. Early diagnosis and systemic treatment will prevent the life-threatening complications of sepsis.
Selection of target mutation in rat gastrointestinal tract E. coli by minute dosage of enrofloxacin.

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Lin, Dachuan; Chen, Kaichao; Li, Ruichao; Liu, Lizhang; Guo, Jiubiao; Yao, Wen; Chen, Sheng

2014-01-01

It has been suggested that bacterial resistance is selected within a mutation selection window of antibiotics. More recent studies showed that even extremely low concentration of antibiotic could select resistant bacteria in vitro. Yet little is known about the exact antibiotic concentration range that can effectively select for resistant organisms in animal gastrointestinal (GI) tract. In this study, the effect of different dosages of enrofloxacin on resistance and mutation development in rat GI tract E. coli was investigated by determining the number of resistant E. coli recoverable from rat fecal samples. Our data showed that high dose antibiotic treatment could effectively eliminate E. coli with single gyrA mutation in the early course of treatment, yet the eradication effects diminished upon prolonged treatment. Therapeutic and sub-therapeutic dose (1/10 and 1/100 of therapeutic doses) of enrofloxacin could effectively select for mutation in GI tract E. coli at the later course of enrofloxacin treatment and during the cessation periods. Surprisingly, very low dose of enrofloxacin (1/1000 therapeutic dose) could also select for mutation in GI tract E. coli at the later course of enrofloxacin treatment, only with slightly lower efficiency. No enrofloxacin-resistant E. coli could be selected at all test levels of enrofloxacin during long term treatment and the strength of antibiotic treatment does not alter the overall level of E. coli in rat GI tract. This study demonstrated that long term antibiotic treatment seems to be the major trigger for the development of target mutations in GI tract E. coli, which provided insight into the rational use of antibiotics in animal husbandry.
Antimicrobial resistance, virulence, and phylogenetic characteristics of Escherichia coli isolates from clinically healthy swine.

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Lay, Khin Khin; Koowattananukul, Chailai; Chansong, Nisit; Chuanchuen, Rungtip

2012-11-01

A total of 344 commensal Escherichia coli isolates from clinically healthy pigs were examined for antimicrobial resistance phenotypes, class 1 integrons, resistance genes, virulence gene profile, and phylogenetic groups. The majority of E. coli isolates were resistant to tetracycline (96.2%) and ampicillin (91.6%). Up to 98% were multidrug resistant. Seventy-three percent of the isolates carried class 1 integrons. Inserted-gene cassette arrays in variable regions included incomplete sat, aadA22, aadA1, dfrA12-aadA2, and sat-psp-aadA2, of which the aadA2 gene cassette was most prevalent (42.9%). Horizontal transfer was detected in eight E. coli isolates carrying class 1 integrons with dfrA12-aadA2 gene cassette array. Sixteen resistance genes were identified among the E. coli isolates with corresponding resistance phenotype. Ten virulence genes (including elt, estA, estB, astA, faeG, fasA, fedA, eaeA, paa, and sepA) were detected, of which fasA was most commonly found (98.3%). Most of the E. coli isolates belonged to phylogenetic group B1. Significantly positive associations were observed between some virulence genes and some resistance phenotypes and genotypes (p antimicrobial resistance-encoding genes and virulence determinants.
Characterization of a membrane-associated serine protease in Escherichia coli

International Nuclear Information System (INIS)

Palmer, S.M.; St John, A.C.

1987-01-01

Three membrane-associated proteolytic activities in Escherichia coli were resolved by DEAE-cellulose chromatography from detergent extracts of the total envelope fraction. On the basis of substrate specificity for the hydrolysis of chromogenic amino acid ester substrates, the first two eluting activities were determined previously to be protease V and protease IV, respectively. The third proteolytic activity eluting from the DEAE-cellulose column was further purified by affinity chromatography on benzamidine-Sepharose 6B. They termed this enzyme protease VI. Protease VI did not hydrolyze any of the chromogenic substrates used in the detection of protease IV and protease V. However, all three enzymes generated acid-soluble fragments from a mixture of E. coli membrane proteins which were biosynthetically labeled with radioactive amino acids. The activity of protease VI was sensitive to serine protease inhibitors. Using [ 3 H]diisopropylfluorophosphate as an active-site labeling reagent, they determined that protease VI has an apparent molecular weight of 43,000 in polyacrylamide gels. All three membrane-associated serine proteases were insensitive to inhibition by Ecotin, an endogenous, periplasmic inhibitor of trypsin
Distribution and characterization of ampicillin- and tetracycline-resistant Escherichia coli from feedlot cattle fed subtherapeutic antimicrobials

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Yanke L Jay

2011-04-01

Full Text Available Abstract Background Feedlot cattle in North America are routinely fed subtherapeutic levels of antimicrobials to prevent disease and improve the efficiency of growth. This practice has been shown to promote antimicrobial resistance (AMR in subpopulations of intestinal microflora including Escherichia coli. To date, studies of AMR in feedlot production settings have rarely employed selective isolation, therefore yielding too few AMR isolates to enable characterization of the emergence and nature of AMR in E. coli as an indicator bacterium. E. coli isolates (n = 531 were recovered from 140 cattle that were housed (10 animals/pen in 14 pens and received no dietary antimicrobials (control - 5 pens, CON, or were intermittently administered subtherapeutic levels of chlortetracycline (5 pens-T, chlortetracycline + sulfamethazine (4 pens-TS, or virginiamycin (5 pens-V for two separate periods over a 9-month feeding period. Phenotype and genotype of the isolates were determined by susceptibility testing and pulsed field gel electrophoresis and distribution of characterized isolates among housed cattle reported. It was hypothesized that the feeding of subtherapeutic antibiotics would increase the isolation of distinct genotypes of AMR E. coli from cattle. Results Overall, patterns of antimicrobial resistance expressed by E. coli isolates did not change among diet groups (CON vs. antibiotic treatments, however; isolates obtained on selective plates (i.e., MA,MT, exhibited multi-resistance to sulfamethoxazole and chloramphenicol more frequently when obtained from TS-fed steers than from other treatments. Antibiograms and PFGE patterns suggested that AMR E. coli were readily transferred among steers within pens. Most MT isolates possessed the tet(B efflux gene (58.2, 53.5, 40.8, and 50.6% of isolates from CON, T, TS, and V steers, respectively whereas among the MA (ampicillin-resistant isolates, the tem1-like determinant was predominant (occurring in 50, 66
Electrochemical disinfection of coliform and Escherichia coli for drinking water treatment by electrolysis method using carbon as an electrode

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Riyanto; Agustiningsih, W. A.

2018-04-01

Disinfection of coliform and E. Coli in water has been performed by electrolysis using carbon electrodes. Carbon electrodes were used as an anode and cathode with a purity of 98.31% based on SEM-EDS analysis. This study was conducted using electrolysis powered by electric field using carbon electrode as the anode and cathode. Electrolysis method was carried out using variations of time (30, 60, 90, 120 minutes at a voltage of 5 V) and voltage (5, 10, 15, 20 V for 30 minutes) to determine the effect of the disinfection of the bacteria. The results showed the number of coliform and E. coli in water before and after electrolysis was 190 and 22 MPN/100 mL, respectively. The standards quality of drinking water No. 492/Menkes/Per/IV/2010 requires the zero content of coliform and E. Coli. Electrolysis with the variation of time and potential can reduce the number of coliforms and E. Coli but was not in accordance with the standards. The effect of hydrogen peroxide (H2O2) to the electrochemical disinfection was determined using UV-Vis spectrophotometer. The levels of H2O2 formed increased as soon after the duration of electrolysis voltage but was not a significant influence to the mortality of coliform and E.coli.
Three-dimensional structure of phosphoribosyl pyrophosphate synthetase from E. coli at 2.71 Å resolution

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Timofeev, V. I., E-mail: inna@ns.crys.ras.ru, E-mail: tostars@mail.ru, E-mail: ugama@yandex.ru [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation); Abramchik, Yu. A. [Russian Academy of Sciences, Shemyakin–Ovchinnikov Institute of Bioorganic Chemistry (Russian Federation); Zhukhlistova, N. E. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation); Muravieva, T. I.; Esipov, R. S. [Russian Academy of Sciences, Shemyakin–Ovchinnikov Institute of Bioorganic Chemistry (Russian Federation); Kuranova, I. P. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)

2016-01-15

Phosphoribosyl pyrophosphate synthetase from Escherichia coli was cloned, purified, and crystallized. Single crystals of the enzyme were grown under microgravity. The X-ray diffraction data set was collected at the Spring-8 synchrotron facility and used to determine the three-dimensional structure of the enzyme by the molecular-replacement method at 2.71 Å resolution. The active and regulatory sites in the molecule of E. coli phosphoribosyl pyrophosphate synthetase were revealed by comparison with the homologous protein from Bacillus subtilis, the structure of which was determined in a complex with functional ligands. The conformations of polypeptide-chain fragments surrounding and composing the active and regulatory sites were shown to be identical in both proteins.
Isolation of Campylobacter spp and Escherichia coli 0157: H7 from ...

African Journals Online (AJOL)

Objectives: To determine the biosafety of a free range indigenous chicken value chain with reference to zoonotic bacteria, Campylobacter spp and Escherichia coli 0157: H7. Design: cross-sectional sampling of chickens and chicken meat carcasses at farm and market level. Setting: Makueni and Nairobi Counties. Subjects: ...
YnfA , a SMR family efflux pump is abundant in Escherichia coli isolates from urinary infection

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S K Sarkar

2015-01-01

Full Text Available A quantitative study was undertaken to determine the expression level of different efflux pumps in multi-drug-resistant (MDR Escherichia coli isolates from urinary infection. We have determined the presence of different efflux pumps and measured the expression level of tolC, mdfA, norE and ynfA genes among 48 isolates by quantitative real-time PCR. The expression level of tolC and ynfA was constantly high and observed among 75-80% of isolates, whereas mdfA and norE were expressed occasionally. Our findings suggest that ynfA, a new SMR efflux pump gene family member increases the antibiotics′ resistance in E. coli.

Antimicrobial-resistant faecal Escherichia coli in wild mammals in central Europe: multiresistant Escherichia coli producing extended-spectrum ß-lactamases in wild boars

DEFF Research Database (Denmark)

Literak, I.; Dolejska, Monika; Radimersky, T.

2010-01-01

Aims: To determine the presence of antibiotic-resistant faecal Escherichia coli in populations of wild mammals in the Czech Republic and Slovakia. Methods and Results: Rectal swabs or faeces collected during 2006-2008 from wild mammals were spread on MacConkey agar and MacConkey agar containing 2...... mg l-1 of cefotaxime. From plates with positive growth, one isolate was recovered and identified as E. coli. Susceptibility to 12 antibiotics was tested using the disk diffusion method. Resistance genes, class 1 and 2 integrons and gene cassettes were detected in resistant isolates by polymerase...... of resistant isolates was 6%. Class 1 and 2 integrons with various gene cassettes were recorded in resistant isolates. From wild boars, five (2%, n(rectal smears) = 293) multiresistant isolates producing ESBL were recovered: one isolate with bla(CTX-M-1) + bla(TEM-1), three with bla(CTX-M-1) and one with bla...
Escherichia coli pyomyositis in an immunocompromised host.

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Sharma, Umesh; Schwan, William R; Agger, William A

2011-08-01

Pyomyositis due to Escherichia coli (E. coil) is rarely reported in immunocompromised patients with hematological malignancy. We present a case report of a 34-year-old man who developed E. coli pyomyositis as a complication of acute myelogenous leukemia (AML). Magnetic resonance imaging (MRI) of the right hip suggested myofascial infection of the gluteal muscles, and a needle muscle aspiration grew E. coli phylogenetic group B2. The patient responded to intravenous piperacillin/tazobactam followed by prolonged oral levofloxacin. Pyomyositis should be suspected in all immunocompromised patients complaining of muscle pain and may exhibit signs of localized muscle infection. Appropriate antibiotic therapy targeting fluoroquinolone-resistant E. coli should be considered for initial empiric therapy of pyomyositis in immunocompromised patients.
A new amperometric method for rapid detection of Escherichia coli density using a self-assembled monolayer-based bienzyme biosensor

International Nuclear Information System (INIS)

Tang Hui; Zhang Wen; Geng Ping; Wang Qingjiang; Jin Litong; Wu Zirong; Lou Min

2006-01-01

A new amperometric method was developed for rapid detection of Escherichia coli (E. coli) density using a bienzyme biosensor. The bienzyme biosensor was fabricated based on the covalent immobilization of laccase and horseradish peroxidase (HRP) at indium tin oxide (ITO) electrode by (3-aminopropyl) triethoxysilane (APTES) monolayer. The bienzyme biosensor showed a high sensitivity in determination of the polyphenolic compounds, which was microbially generated from the salicylic acid (SA) added into the culture medium during the course of E. coli metabolism. Since the amount of polyphenolic compounds depends on E. coli density, the bienzyme biosensor was applied for the rapid and high sensitive detection of E. coli density after the E. coli solution was incubated in culture medium with salicylic acid for 2.5 h at 37 deg. C. By chronoamperometry, the amplified response current was obtained at the bienzyme biosensor, due to the substrate recycling of the polyphenolic compounds driven by bienzyme-catalyzed oxidation and electrochemical reduction. The amplified response current at the biosensor was linear with the E. coli density ranging from 1.6 x 10 3 to 1.0 x 10 7 cells/mL. The bienzyme biosensor could detect the E. coli density with a detection limit of 9.7 x 10 2 cells/mL within 3 h
Resistance trends and risk factors of extended spectrum β-lactamases in Escherichia coli infections in Aleppo, Syria.

Science.gov (United States)

Al-Assil, Bodour; Mahfoud, Maysa; Hamzeh, Abdul Rezzak

2013-07-01

Recently, there has been a notable surge in urinary tract infections (UTIs) by extended spectrum β-lactamase (ESBL)-producing Escherichia coli, which considerably limits treatment options. This study aimed to determine prevalence, phenotypic patterns, and ESBL-production status of E coli in isolates from UTI patients along with uncovering locally relevant risk factors for contracting ESBL-producing E coli infections. One hundred four nonrepetitive urine samples were collected from 3 major hospitals in Aleppo, Syria. Antibiotic susceptibility and ESBL production were studied by disc diffusion and double disk synergy tests according to Clinical Laboratory Standards Institute guidelines. Epidemiologic analysis was done using χ(2) and multivariate logistic regression tests. This study revealed high prevalence of multidrug-resistant (MDR) E coli reaching 63%, whereas ESBL-producing E coli exceeded 52%. The latter exhibited alarmingly elevated levels of coresistance to non-β-lactam antibiotics leading to vast increase in MDR rates in comparison with non-ESBL-producing E coli (83.6% vs 12.2%, respectively). We found previous exposure to third-generation cephalosporins and fluoroquinolones to be a significant risk factor for ESBL-producing E coli infections, in addition to other known factors such as hospitalization and catheterization. Tigecycline and carbapenems demonstrated near perfect efficacy against tested E coli, so they rank high among treatment options. Copyright © 2013 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.
Determination of the indicator bacteria in irradiated minced meat

International Nuclear Information System (INIS)

Halkman, H.B.D.; Basbayraktar, V.; Kozat, P.; Yazici, N.; Cetinkaya, N.; Halkman, A.K

2002-01-01

To inhibit Escherichia coli O157:H7 and determine a indicator bacteria for irradiation procedure in minced meat, this study evaluated increased irradiation doses on five strains of each of the following bacteria: 5 strains E. coli type 1 and 4 strains E. coli O157:H7. E. coli type 1 mixture was added into the mixed in ratio 1:100000 of E. coli type l to samples and E. coli O157:H7 mixture was added into the mixed in five different ratios namely 1:10, 1:100, 1:1000, 1:10000, 1:100000 of E coli O157:H7 in the minced meat. A range of irradiation doses from 1 kGy to 4 kGy was investigated for the inhibition of E. coli O157:H7 and the resistance of E. coli type 1 to irradiation. After irradiation, E. coli O157:H7 and E. coli type 1 were counted in the irradiated minced meat by using MPN techniques. D 10 values of each bacteria were be measured as 0.3 kGy and 0.55 kGy for E. coli 0157:H7 and E. coli type 1 respectively. This study showed that 1.5 kGy irradiation can inactivate 10 5 g/O157:H7 serotype and 10 3 g / E. coli type 1, this inactivation level is adequate for safety consumption of minced meat such as hamburger even if undercooking conditions. Increased irradiation doses were the most effective on E. coli O157:H7. The results show that E. coli type 1 is more resistant to than E. coli O157:H7 and other natural non-Pathogenic cohabitant bacteria and E. coli type 1 is an adequate indicator for the efficiency of irradiation against to O157:H7 serotype in minced meat
Effects of intramuscularly administered enrofloxacin on the susceptibility of commensal intestinal Escherichia coli in pigs (sus scrofa domestica).

Science.gov (United States)

Römer, Antje; Scherz, Gesine; Reupke, Saskia; Meißner, Jessica; Wallmann, Jürgen; Kietzmann, Manfred; Kaspar, Heike

2017-12-04

In the European Union, various fluoroquinolones are authorised for the treatment of food producing animals. Each administration poses an increased risk of development and spread of antimicrobial resistance. The aim of this study was to investigate the impact of parenteral administration of enrofloxacin on the prevalence of enrofloxacin and ciprofloxacin susceptibilities in the commensal intestinal E. coli population. E. coli isolates from faeces of twelve healthy pigs were included. Six pigs were administered enrofloxacin on day 1 to 3 and after two weeks for further three days. The other pigs formed the control group. MIC values were determined. Virulence and resistance genes were detected by PCR. Phylogenetic grouping was performed by PCR. Enrofloxacin and ciprofloxacin were analysed in sedimentation samples by HPLC. Susceptibility shifts in commensal E. coli isolates were determined in both groups. Non-wildtype E. coli could be cultivated from two animals of the experimental group for the first time one week after the first administration and from one animal of the control group on day 28. The environmental load with enrofloxacin in sedimentation samples showed the highest amount between days one and five. The repeated parenteral administration of enrofloxacin to pigs resulted in rapidly increased MIC values (day 28: MIC up to 4 mg/L, day 35: MIC ≥ 32mg/L). E. coli populations of the control group in the same stable without direct contact to the experimental group were affected. The parenteral administration of enrofloxacin to piglets considerably reduced the number of the susceptible intestinal E. coli population which was replaced by E. coli strains with increased MIC values against enrofloxacin. Subsequently also pigs of the control were affected suggesting a transferability of strains from the experimental group through the environment to the control group especially as we could isolate the same PFGE strains from both pig groups and the environment.
Determination of Silver Ions Toxicity in Short-Term and Long-Term Experiments Using a Luminescent Recombinant Strain of E. coli

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Tatiana P. Yudina

2013-01-01

Full Text Available The effects of silver ions on the luminescent recombinant strain of Escherichia coli carrying luxCDABE operon of Vibrio fischeri were investigated. The toxicity of silver ions was determined in 30 minutes and in chronic 24 hours experiments. Changes in the luminescence intensity and in the growth rate of bacteria were considered as a measure of silver ions toxicity within the range of concentrations applied. The effect of silver ions was demonstrated to be strongly dependent on the concentration of bacteria and on the medium composition. EC50 values were 0.018 mg/l after 30 min exposure and 0.014 mg/l after 10 hours of bacterial growth. Comparison of two modifications of the experiment showed that silver ions have a strong non-specific toxicity, as well as a specific effect on bacterial cells
Norwegian patients and retail chicken meat share cephalosporin-resistant Escherichia coli and IncK/blaCMY-2 resistance plasmids

DEFF Research Database (Denmark)

Berg, E. S.; Wester, A. L.; Ahrenfeldt, Johanne

2017-01-01

In 2012 and 2014 the Norwegian monitoring programme for antimicrobial resistance in the veterinary and food production sectors (NORM-VET) showed that 124 of a total of 406 samples (31%) of Norwegian retail chicken meat was contaminated with extended-spectrum cephalosporin-resistant Escherichia coli....... The aim of this study was to compare selected cephalosporin-resistant E. coli from humans and poultry to determine their genetic relatedness based on whole genome sequencing (WGS). E. coli representing three prevalent cephalosporin-resistant multi-locus sequence types (STs) isolated from poultry (n=17...
Expression of goose parvovirus whole VP3 protein and its epitopes in Escherichia coli cells.

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Tarasiuk, K; Woźniakowski, G; Holec-Gąsior, L

2015-01-01

The aim of this study was the expression of goose parvovirus capsid protein (VP3) and its epitopes in Escherichia coli cells. Expression of the whole VP3 protein provided an insufficient amount of protein. In contrast, the expression of two VP3 epitopes (VP3ep4, VP3ep6) in E. coli, resulted in very high expression levels. This may suggest that smaller parts of the GPV antigenic determinants are more efficiently expressed than the complete VP3 gene.
Gene encoding virulence markers among Escherichia coli isolates ...

African Journals Online (AJOL)

River water sources and diarrhoeic stools of residents in the Venda Region, Limpopo Province of South Africa were analysed for the prevalence of Escherichia coli (E. coli) and the presence of virulence genes among the isolates. A control group of 100 nondiarrhoeic stool samples was included. Escherichia coli was ...
Genomic Comparative Study of Bovine Mastitis Escherichia coli.

Science.gov (United States)

Kempf, Florent; Slugocki, Cindy; Blum, Shlomo E; Leitner, Gabriel; Germon, Pierre

2016-01-01

Escherichia coli, one of the main causative agents of bovine mastitis, is responsible for significant losses on dairy farms. In order to better understand the pathogenicity of E. coli mastitis, an accurate characterization of E. coli strains isolated from mastitis cases is required. By using phylogenetic analyses and whole genome comparison of 5 currently available mastitis E. coli genome sequences, we searched for genotypic traits specific for mastitis isolates. Our data confirm that there is a bias in the distribution of mastitis isolates in the different phylogenetic groups of the E. coli species, with the majority of strains belonging to phylogenetic groups A and B1. An interesting feature is that clustering of strains based on their accessory genome is very similar to that obtained using the core genome. This finding illustrates the fact that phenotypic properties of strains from different phylogroups are likely to be different. As a consequence, it is possible that different strategies could be used by mastitis isolates of different phylogroups to trigger mastitis. Our results indicate that mastitis E. coli isolates analyzed in this study carry very few of the virulence genes described in other pathogenic E. coli strains. A more detailed analysis of the presence/absence of genes involved in LPS synthesis, iron acquisition and type 6 secretion systems did not uncover specific properties of mastitis isolates. Altogether, these results indicate that mastitis E. coli isolates are rather characterized by a lack of bona fide currently described virulence genes.
Fimbrial adhesins from extraintestinal Escherichia coli

DEFF Research Database (Denmark)

Klemm, Per; Hancock, Viktoria; Schembri, Mark A.

2010-01-01

Extraintestinal pathogenic Escherichia coli (ExPEC) represent an important subclass of E. coli that cause a wide spectrum of diseases in human and animal hosts. Fimbriae are key virulence factors of ExPEC strains. These long surface located rod-shaped organelles mediate receptor-specific attachment...
Relation between tetR and tetA expression in tetracycline resistant Escherichia coli

DEFF Research Database (Denmark)

Møller, Thea S. B.; Overgaard, Martin; Nielsen, Søren S.

2016-01-01

Background: Tetracyclines are among the most used antibiotics in livestock worldwide. Resistance is widely disseminated in Escherichia coli, where it is generally mediated by tetracycline efflux pumps, such as TetA. Expression of tetracycline efflux pumps is tightly controlled by the repressor Tet......R, which has been shown to be tetracycline-responsive at sub-MIC tetracycline concentrations. The objective of this study was to investigate the effects of increasing tetracycline concentrations on the growth of TetA-producing E. coli, and to determine how expression of tetA and tetR related to each other...... in different growth phases in the presence of tetracycline. Results: A tetracycline resistant E. coli strain containing tetA and tetR on the chromosome was constructed and cultured in the presence of increasing concentrations of tetracycline. Expression of tetR and tetA was measured at four time points...
Influence of very short patch mismatch repair on SOS inducing lesions after aminoglycoside treatment in Escherichia coli.

Science.gov (United States)

Baharoglu, Zeynep; Mazel, Didier

2014-01-01

Low concentrations of aminoglycosides induce the SOS response in Vibrio cholerae but not in Escherichia coli. In order to determine whether a specific factor present in E. coli prevents this induction, we developed a genetic screen where only SOS inducing mutants are viable. We identified the vsr gene coding for the Vsr protein of the very short patch mismatch repair (VSPR) pathway. The effect of mismatch repair (MMR) mutants was also studied. We propose that lesions formed upon aminoglycoside treatment are preferentially repaired by VSPR without SOS induction in E. coli and by MMR when VSPR is impaired. Copyright © 2014 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.
Ethylenediaminetetraacetate and lysozyme improves antimicrobial activities of ovotransferrin against Escherichia coli O157:H7.

Science.gov (United States)

Ko, K Y; Mendoncam, A F; Ismail, H; Ahn, D U

2009-02-01

The aim of this study was to evaluate the effect of EDTA, lysozyme, or the combination of EDTA and lysozyme on the antibacterial activity of ovotransferrin against Escherichia coli O157:H7. Ovotransferrin solutions (20 mg/mL) containing 100 mM NaHCO3 (OS) with added EDTA (2.0 or 2.5 mg/mL), lysozyme (1.0, 1.5, or 2.0 mg/mL), or both were prepared. The antibacterial activities of OS, OSE (OS+EDTA), or OSL (OS+lysozyme) against E. coli O157:H7 in model systems were investigated by turbidity and viability tests. In addition, OSE, OSL, or OSEL (OS+EDTA+lysozyme) was applied to irradiated pork chops and commercial hams to determine whether the solutions had antibacterial activity on meat products. The effect of the initial cell population on the antibacterial activity of OSE, OSL, and OSEL was determined. Ethylenediaminetetraacetate at 2 mg/mL plus OS induced a reduction of approximately 3 to 4 log in viable E. coli O157:H7 cells in brain heart infusion broth media, and 1 mg/mL of lysozyme plus OS resulted in a reduction of approximately 0.5 to 1.0 log during a 36-h incubation at 35 degrees C. However, neither OSE nor OSEL showed a significant antibacterial effect on pork chops and hams during storage at 10 degrees C. The initial cell number in media did not affect the antibacterial activity of OSE or OSEL against E. coli O157:H7. This study demonstrates that combinations of ovotransferrin, NaHCO3, and EDTA have the potential to control E. coli O157:H7.
Prevalence of Class D Carbapenemases among Extended-Spectrum β-Lactamases Producing Escherichia coli Isolates from Educational Hospitals in Shahrekord

Science.gov (United States)

Damavandi, Mohammad-Sadegh; Latif Pour, Mohammad

2016-01-01

Introduction Extended-spectrum β-lactamases (ESBLs) are a set of plasmid-borne, various and quickly evolving enzymes that are a main therapeutic issue now-a-days for inpatient and outpatient treatment. Aim The aim of this study was to determine multi-drug resistance (MDR) and ESBLs producing E. coli strains, prevalence of class D Carbapenemases among ESBLs producing Escherichia coli isolates from educational hospitals in Shahrekord, Iran. Materials and Methods Uropathogenic Escherichia coli strains were isolated from patients with Urinary Tract Infections (UTIs). The agar disc diffusion test was used to characterize the antimicrobial sensitivity of the E. coli isolates. The ESBL positive strains were identified by phenotypic double-disk synergy test, by third-generation cephalosporin in combination with or without clavulanic acid. Multiplex PCR was carried out for detection of the three families of OXA-type carbapenamases including OXA-23, OXA-24, and OXA-48 in E. coli strains. Results All bacterial isolates were susceptible to meropenem. Ninety isolates produced ESBL, 55 E. coli isolates from inpatients, and 35 isolates from outpatients, with a significant association (presistance in E. coli isolates. PMID:27462579
The Intriguing Evolutionary Journey of Enteroinvasive E. coli (EIEC toward Pathogenicity

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Martina Pasqua

2017-12-01

Full Text Available Among the intestinal pathogenic Escherichia coli, enteroinvasive E. coli (EIEC are a group of intracellular pathogens able to enter epithelial cells of colon, multiplicate within them, and move between adjacent cells with a mechanism similar to Shigella, the ethiological agent of bacillary dysentery. Despite EIEC belong to the same pathotype of Shigella, they neither have the full set of traits that define Shigella nor have undergone the extensive gene decay observed in Shigella. Molecular analysis confirms that EIEC are widely distributed among E. coli phylogenetic groups and correspond to bioserotypes found in many E. coli serogroups. Like Shigella, also in EIEC the critical event toward a pathogenic life-style consisted in the acquisition by horizontal gene transfer of a large F-type plasmid (pINV containing the genes required for invasion, intracellular survival, and spreading through the intestinal mucosa. In Shigella, the ample gain in virulence determinants has been counteracted by a substantial loss of functions that, although important for the survival in the environment, are redundant or deleterious for the life inside the host. The pathoadaptation process that has led Shigella to modify its metabolic profile and increase its pathogenic potential is still in infancy in EIEC, although maintenance of some features typical of E. coli might favor their emerging relevance as intestinal pathogens worldwide, as documented by recent outbreaks in industrialized countries. In this review, we will discuss the evolution of EIEC toward Shigella-like invasive forms going through the epidemiology, including the emergence of new virulent strains, their genome organization, and the complex interactions they establish with the host.
Reduction of Escherichia coli 0157:H7 in shredded iceberg lettuce by chlorination and gamma irradiation

Energy Technology Data Exchange (ETDEWEB)

Foley, D.M. E-mail: dfoley@chapman.edu; Dufour, A.; Rodriguez, L.; Caporaso, F.; Prakash, A

2002-03-01

Lettuce was inoculated with a six-strain cocktail of acid-adapted Escherichia coli 0157:H7 at a level of 1x10{sup 7} CFU/g. Following chlorination at 200 {mu}g/ml, the lettuce was irradiated at 0.15, 0.38, or 0.55 kGy using a {sup 60}Co source. Survival of E. coli 0157:H7, aerobic mesophiles and yeast and molds were measured over a period of 10 days. For quality analysis, chlorinated lettuce was subjected to irradiation at 0.33 and 0.53 kGy and stored at 1.0 deg. C, 4.0 deg. C or 7.0 deg. C. Changes in texture and color were determined by instrumental means and changes in flavor, odor, and visual quality were determined by sensory testing. Chlorination plus irradiation at 0.55 kGy produced a 5.4-log reduction in E. coli 0157:H7 levels. Chlorination alone reduced the E. coli 0157:H7 counts by 1-2 logs. Irradiation at 0.55 kGy was also effective in reducing standard plate counts and yeast and mold counts. Irradiation at this level did not cause softening of lettuce and sensory attributes were not adversely affected. In general, appearance and flavor were affected more by the length of storage than by temperature conditions. The 5+log reduction in E. coli counts and lack of adverse effects on sensory attributes indicate that low-dose irradiation can improve the safety and shelf-life of fresh-cut iceberg lettuce for retail sale or food service.
Reduction of Escherichia coli 0157:H7 in shredded iceberg lettuce by chlorination and gamma irradiation

International Nuclear Information System (INIS)

Foley, D.M.; Dufour, A.; Rodriguez, L.; Caporaso, F.; Prakash, A.

2002-01-01

Lettuce was inoculated with a six-strain cocktail of acid-adapted Escherichia coli 0157:H7 at a level of 1x10 7 CFU/g. Following chlorination at 200 μg/ml, the lettuce was irradiated at 0.15, 0.38, or 0.55 kGy using a 60 Co source. Survival of E. coli 0157:H7, aerobic mesophiles and yeast and molds were measured over a period of 10 days. For quality analysis, chlorinated lettuce was subjected to irradiation at 0.33 and 0.53 kGy and stored at 1.0 deg. C, 4.0 deg. C or 7.0 deg. C. Changes in texture and color were determined by instrumental means and changes in flavor, odor, and visual quality were determined by sensory testing. Chlorination plus irradiation at 0.55 kGy produced a 5.4-log reduction in E. coli 0157:H7 levels. Chlorination alone reduced the E. coli 0157:H7 counts by 1-2 logs. Irradiation at 0.55 kGy was also effective in reducing standard plate counts and yeast and mold counts. Irradiation at this level did not cause softening of lettuce and sensory attributes were not adversely affected. In general, appearance and flavor were affected more by the length of storage than by temperature conditions. The 5+log reduction in E. coli counts and lack of adverse effects on sensory attributes indicate that low-dose irradiation can improve the safety and shelf-life of fresh-cut iceberg lettuce for retail sale or food service
The cell shape proteins MreB and MreC control cell morphogenesis by positioning cell wall synthetic complexes.

Science.gov (United States)

Divakaruni, Arun V; Baida, Cyril; White, Courtney L; Gober, James W

2007-10-01

MreB, the bacterial actin homologue, is thought to function in spatially co-ordinating cell morphogenesis in conjunction with MreC, a protein that wraps around the outside of the cell within the periplasmic space. In Caulobacter crescentus, MreC physically associates with penicillin-binding proteins (PBPs) which catalyse the insertion of intracellularly synthesized precursors into the peptidoglycan cell wall. Here we show that MreC is required for the spatial organization of components of the peptidoglycan-synthesizing holoenzyme in the periplasm and MreB directs the localization of a peptidoglycan precursor synthesis protein in the cytosol. Additionally, fluorescent vancomycin (Van-FL) labelling revealed that the bacterial cytoskeletal proteins MreB and FtsZ, as well as MreC and RodA, were required for peptidoglycan synthetic activity. MreB and FtsZ were found to be required for morphogenesis of the polar stalk. FtsZ was required for a cell cycle-regulated burst of peptidoglycan synthesis early in the cell cycle resulting in the synthesis of cross-band structures, whereas MreB was required for lengthening of the stalk. Thus, the bacterial cytoskeleton and cell shape-determining proteins such as MreC, function in concert to orchestrate the localization of cell wall synthetic complexes resulting in spatially co-ordinated and efficient peptidoglycan synthetic activity.

Cloacael Carriage and Multidrug Resistance Escherichia coli O157:H7 from Poultry Farms, Eastern Ethiopia.

Science.gov (United States)

Shecho, Mude; Thomas, Naod; Kemal, Jelalu; Muktar, Yimer

2017-01-01

A cross-sectional study was carried out to determine antimicrobial drug resistance patterns of E. coli O157:H7 isolates and estimate the level of the pathogen. A total of 194 cloacae swab samples were collected randomly in two poultry farms. Standard cultural, biochemical, and serological (latex agglutination) methods were used to isolate E. coli O157:H7. The isolates were subjected to antimicrobial susceptibility testing using disc diffusion method. Out of 194 cloacae samples examined, 13.4% ( n = 26) were found to be positive for E. coli O157:H7. The finding indicated differences in E. coli O157:H7 infection among the different risk factors. Chicken from Adele Poultry Farm showed higher E. coli O157:H7 infection (OR = 3.89) than Haramaya University poultry farm and young birds had more infection (OR = 4.62) than adult birds. Of the total 14 antimicrobials included in the panel of study, the susceptibility results were varied with 96.15% and 0% E. coli O157:H7 isolates expressing resistance to erythromycin, clindamycin, spectinomycin, and ciprofloxacin, respectively. Multidrug resistance to more than two antimicrobial agents was detected in 24 (92.30%) of the isolates. The study showed high presence of antimicrobial resistant isolates of E. coli O157:H7. Further study is required to better understand the ecology and evolution of bacterial resistance to antimicrobial agents.
Cloacael Carriage and Multidrug Resistance Escherichia coli O157:H7 from Poultry Farms, Eastern Ethiopia

Directory of Open Access Journals (Sweden)

Mude Shecho

2017-01-01

Full Text Available A cross-sectional study was carried out to determine antimicrobial drug resistance patterns of E. coli O157:H7 isolates and estimate the level of the pathogen. A total of 194 cloacae swab samples were collected randomly in two poultry farms. Standard cultural, biochemical, and serological (latex agglutination methods were used to isolate E. coli O157:H7. The isolates were subjected to antimicrobial susceptibility testing using disc diffusion method. Out of 194 cloacae samples examined, 13.4% (n=26 were found to be positive for E. coli O157:H7. The finding indicated differences in E. coli O157:H7 infection among the different risk factors. Chicken from Adele Poultry Farm showed higher E. coli O157:H7 infection (OR = 3.89 than Haramaya University poultry farm and young birds had more infection (OR = 4.62 than adult birds. Of the total 14 antimicrobials included in the panel of study, the susceptibility results were varied with 96.15% and 0% E. coli O157:H7 isolates expressing resistance to erythromycin, clindamycin, spectinomycin, and ciprofloxacin, respectively. Multidrug resistance to more than two antimicrobial agents was detected in 24 (92.30% of the isolates. The study showed high presence of antimicrobial resistant isolates of E. coli O157:H7. Further study is required to better understand the ecology and evolution of bacterial resistance to antimicrobial agents.
Incidence of temonera, sulphuhydryl variables and cefotaximase genes associated with ?-lactamase producing escherichia coli in clinical isolates

OpenAIRE

Isaiah, Ibeh Nnana; Nche, Bikwe Thomas; Nwagu, Ibeh Georgina; Nwagu, Ibeh Isaiah

2011-01-01

Background: The occurrence of the different types of Extended spectrum beta Lactamase producing Escherichia coli with the, Sulphurhydryl variable, Temonera and the Cefotaximase have been on the rise Aim: The study was to determine the prevalence of extended spectrum beta lactamase gene resistance across the clinical isolates of hospitalized patients. Materials and Method: Three hundred and fifty isolates of Escherichia coli were received from different clinical specimens. The susceptibility p...
PATHOGENIC POTENTIALS OF ESCHERICHIA COLI ISOLATED ...

African Journals Online (AJOL)

Electrolyte and haematological parameters in rabbits infected with pathogenic isolates of Escherichia coli from rural water supplies in Rivers State, Nigeria, where monitored. Rabbits were orally infected with suspension containing 3x107 cfu /ml of Escherichia coli to induce diarrhoea, and the electrolyte (sodium, potassium ...
Is Longitudinal Division in Rod-Shaped Bacteria a Matter of Swapping Axis?

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Tanneke den Blaauwen

2018-05-01

Full Text Available The morphology of bacterial species shows a wealth of variation from star-shaped to spherical and rod- to spiral-shaped, to mention a few. Their mode of growth and division is also very diverse and flexible ranging from polar growth and lateral surface increase to midcell expansion and from perpendicular to longitudinal asymmetric division. Gammaproteobacterial rod-shaped species such as Escherchia coli divide perpendicularly and grow in length, whereas the genetically very similar rod-shaped symbiotic Thiosymbion divide longitudinally, and some species even divide asynchronously while growing in width. The ovococcal Streptococcus pneumoniae also lengthens and divides perpendicularly, yet it is genetically very different from E. coli. Are these differences as dramatic as is suggested by visual inspection, or can they all be achieved by subtle variation in the regulation of the same protein complexes that synthesize the cell envelope? Most bacteria rely on the cytoskeletal polymer FtsZ to organize cell division, but only a subset of species use the actin homolog MreB for length growth, although some of them are morphologically not that different. Poles are usually negative determinant for cell division. Curved cell poles can be inert or active with respect to peptidoglycan synthesis, can localize chemotaxis and other sensing proteins or other bacterial equipment, such as pili, depending on the species. But what is actually the definition of a pole? This review discusses the possible common denominators for growth and division of distinct and similar bacterial species.
Temperature sensitivity of the penicillin-induced autolysis mechanism in nongrowing cultures of Escherichia coli.

OpenAIRE

Kusser, W; Ishiguro, E E

1987-01-01

The effect of incubation temperature on the ampicillin-induced autolysis of nongrowing Escherichia coli was determined. The autolysis mechanisms in amino acid-deprived relA mutant cells treated with chloramphenicol were temperature sensitive. This temperature-sensitive autolysis was demonstrated in three independent ways: turbidimetric determinations, viable cell counts, and solubilization of radiolabeled peptidoglycan.
Synergistic effects in mixed Escherichia coli biofilms

DEFF Research Database (Denmark)

Reisner, A.; Holler, B.M.; Molin, Søren

2006-01-01

Bacterial biofilms, often composed of multiple species and genetically distinct strains, develop under complex influences of cell-cell interactions. Although detailed knowledge about the mechanisms underlying formation of single-species laboratory biofilms has emerged, little is known about...... the pathways governing development of more complex heterogeneous communities. In this study, we established a laboratory model where biofilm-stimulating effects due to interactions between genetically diverse strains of Escherichia coli were monitored. Synergistic induction of biofilm formation resulting from...... the cocultivation of 403 undomesticated E. coli strains with a characterized E. coli K-12 strain was detected at a significant frequency. The survey suggests that different mechanisms underlie the observed stimulation, yet synergistic development of biofilm within the subset of E. coli isolates (n = 56) exhibiting...
Determining the Specificity of Cascade Binding, Interference, and Primed Adaptation In Vivo in the Escherichia coli Type I-E CRISPR-Cas System

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Lauren A. Cooper

2018-04-01

Full Text Available In clustered regularly interspaced short palindromic repeat (CRISPR-Cas (CRISPR-associated immunity systems, short CRISPR RNAs (crRNAs are bound by Cas proteins, and these complexes target invading nucleic acid molecules for degradation in a process known as interference. In type I CRISPR-Cas systems, the Cas protein complex that binds DNA is known as Cascade. Association of Cascade with target DNA can also lead to acquisition of new immunity elements in a process known as primed adaptation. Here, we assess the specificity determinants for Cascade-DNA interaction, interference, and primed adaptation in vivo, for the type I-E system of Escherichia coli. Remarkably, as few as 5 bp of crRNA-DNA are sufficient for association of Cascade with a DNA target. Consequently, a single crRNA promotes Cascade association with numerous off-target sites, and the endogenous E. coli crRNAs direct Cascade binding to >100 chromosomal sites. In contrast to the low specificity of Cascade-DNA interactions, >18 bp are required for both interference and primed adaptation. Hence, Cascade binding to suboptimal, off-target sites is inert. Our data support a model in which the initial Cascade association with DNA targets requires only limited sequence complementarity at the crRNA 5′ end whereas recruitment and/or activation of the Cas3 nuclease, a prerequisite for interference and primed adaptation, requires extensive base pairing.
Characterisation of Commensal Escherichia coli Isolated from Apparently Healthy Cattle and Their Attendants in Tanzania.

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Balichene P Madoshi

Full Text Available While pathogenic types of Escherichia coli are well characterized, relatively little is known about the commensal E. coli flora. In the current study, antimicrobial resistance in commensal E. coli and distribution of ERIC-PCR genotypes among isolates of such bacteria from cattle and cattle attendants on cattle farms in Tanzania were investigated. Seventeen E. coli genomes representing different ERIC-PCR types of commensal E. coli were sequenced in order to determine their possible importance as a reservoir for both antimicrobial resistance genes and virulence factors. Both human and cattle isolates were highly resistant to tetracycline (40.8% and 33.1%, sulphamethazole-trimethoprim (49.0% and 8.8% and ampicillin (44.9% and 21.3%. However, higher proportion of resistant E. coli and higher frequency of resistance to more than two antimicrobials was found in isolates from cattle attendants than isolates from cattle. Sixteen out of 66 ERIC-PCR genotypes were shared between the two hosts, and among these ones, seven types contained isolates from cattle and cattle attendants from the same farm, suggesting transfer of strains between hosts. Genome-wide analysis showed that the majority of the sequenced cattle isolates were assigned to phylogroups B1, while human isolates represented phylogroups A, C, D and E. In general, in silico resistome and virulence factor identification did not reveal differences between hosts or phylogroups, except for lpfA and iss found to be cattle and B1 phylogroup specific. The most frequent plasmids replicon genes found in strains from both hosts were of IncF type, which are commonly associated with carriage of antimicrobial and virulence genes. Commensal E. coli from cattle and attendants were found to share same genotypes and to carry antimicrobial resistance and virulence genes associated with both intra and extraintestinal E. coli pathotypes.
Faecal Escherichia coli from patients with E. coli urinary tract infection and healthy controls who have never had a urinary tract infection

DEFF Research Database (Denmark)

Nielsen, Karen L; Dynesen, Pia; Larsen, Preben

2014-01-01

Urinary tract infections (UTIs) are primarily caused by Escherichia coli with the patient's own faecal flora acting as a reservoir for the infecting E. coli. Here we sought to characterize the E. coli faecal flora of UTI patients and healthy controls who had never had a UTI. Up to 20 E. coli...... colonies from each rectal swab were random amplified polymorphic DNA (RAPD) typed for clonality, dominance in the sample and correlation to the infecting UTI isolate in patients. Each distinct clone was phylotyped and tested for antimicrobial susceptibility. Eighty-seven per cent of the UTI patients...... carried the infecting strain in their faecal flora, and faecal clones causing UTI were more often dominant in the faecal flora. Patients had a larger diversity of E. coli in their gut flora by carrying more unique E. coli clones compared to controls, and patient faecal clones were more often associated...
Correlation of Aerobic Exercise and High Nitrate Diet with Population of Eschericia coli in the Digestive Tract of Liver Cirrhosis Individuals

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Retti Nurlaili

2017-12-01

Full Text Available Background: In liver cirrhosis, the population of E coli is increased. conditions such as reduced intestinal. Escherichia coli with 2 enzyme nitrate reductase (NRF and Nir reduce nitrate to nitrite and subsequently converted to ammonia (99% and nitric oxide (1% in anaerobic condition. Regular aerobic exercise 2-3 times/week for 30 minutes resulted in increased 2,3-DPG which reduces the activity of E. coli to reduce nitrate to nitrite and ammonia, which only works on the anaerobic state. High Nitrate Diets lead to increased nitrate reducing bacteria such as E. coli resulting in the reduction of nitrate excess produce nitrite and ammonia in large quantities. Probiotic Lactobacillus spp. can suppress the growth of bacterial endotoxins and pathogens such as E. coli and other Enterobacteriaceae. This study aimed to determine the correlation of aerobic exercise and a high nitrate diet in gastrointestinal populations of Escherichia coli gastrointestinal tract in patient with liver cirrhosis. Method: This was a descriptive-experimental study in liver cirrhosis patients Child Pugh A/B in outpatient clinic Saiful Anwar Hospital in August 2015. Respondents were asked to fill out a questionnaire with information about the demographic data, the nitrate diet, aerobic exercise, other medical data and sanitation, and stool samples were taken for faecal culture. Eta Correlation statistical test was used to determine the correlation of aerobic exercise and a high nitrate diet high in population of E. coli. The significant difference are indicated by p < 0.005. Results: A total of 36 patients diagnosed with liver cirrhosis Child Pugh A/B, 14 (39% underwent aerobic exercise 3x /week, as many as 25 (70% consume a high nitrate diet. There was a strong relationship between aerobic exercise and high nitrate diet with population of E. coli (Ƞ = 0.725; p < 0.05. Conclusion: There was a strong relationship between aerobic exercise and high nitrate diet with a population
Pharmacokinetics, bioavailability and dose assessment of Cefquinome against Escherichia coli in black swans (Cygnus atratus).

Science.gov (United States)

Zhao, Dong-Hao; Wang, Xu-Feng; Wang, Qiang; Li, Liu-Dong

2017-07-28

The objective of this study is to investigate pharmacokinetics and dose regimens of cefquinome in black swans following intravenous (IV) and intramuscular (IM) administration at a single dose of 2 mg/kg. The MICs of cefquinome against 49 Escherichia coli isolates from black swans were determined. Monte Carlo simulation was applied to conduct the dose regimen assessment and optimization of cefquinome against E. coli in black swans, and a pharmacokinetic/pharmacodynamic (PK/PD) cutoff was established for E. coli isolates obtained in this study. The PK parameters of T 1/2α (0.31 h), T 1/2β (1.69 h) and Cl B (0.13 L/kg·h) indicated a rapid distribution and elimination of cefquinome in black swans after IV administration. After IM injection, the corresponding PK parameters of T 1/2Ka , T 1/2Ke , T max , C max , and F were 0.12 h, 1.62 h, 0.39 h, 5.71 μg/mL and 74.2%, respectively. The MICs of cefquinome against black swans E. coli ranged from 0.03 to 8 μg/mL, with MIC 50 and MIC 90 of 0.06 and 0.5 μg/mL, respectively. The PK/PD cutoff of cefquinome against E. coli was determined to be 0.2 μg/mL. Monte Carlo simulation showed that the nominal dose regimen (2 mg/kg/24 h) could not achieve a satisfactory probability of target attainment (PTA) for %T MIC ≥ 50%, indicating a risk of treatment failure and the development of potential drug resistance. The current daily dosage of cefquinome when divided into 12-h interval (1 mg/kg/12 h) may be effective for the treatment of E. coli infections with an MIC ≤0.5 μg/mL.
Fitness of Enterohemorrhagic Escherichia coli (EHEC)/Enteroaggregative E. coli O104:H4 in Comparison to That of EHEC O157: Survival Studies in Food and In Vitro.

Science.gov (United States)

Böhnlein, Christina; Kabisch, Jan; Meske, Diana; Franz, Charles M A P; Pichner, Rohtraud

2016-11-01

In 2011, one of the world's largest outbreaks of hemolytic-uremic syndrome (HUS) occurred, caused by a rare Escherichia coli serotype, O104:H4, that shared the virulence profiles of Shiga toxin-producing E. coli (STEC)/enterohemorrhagic E. coli (EHEC) and enteroaggregative E. coli (EAEC). The persistence and fitness factors of the highly virulent EHEC/EAEC O104:H4 strain, grown either in food or in vitro, were compared with those of E. coli O157 outbreak-associated strains. The log reduction rates of the different EHEC strains during the maturation of fermented sausages were not significantly different. Both the O157:NM and O104:H4 serotypes could be shown by qualitative enrichment to be present after 60 days of sausage storage. Moreover, the EHEC/EAEC O104:H4 strain appeared to be more viable than E. coli O157:H7 under conditions of decreased pH and in the presence of sodium nitrite. Analysis of specific EHEC strains in experiments with an EHEC inoculation cocktail showed a dominance of EHEC/EAEC O104:H4, which could be isolated from fermented sausages for 60 days. Inhibitory activities of EHEC/EAEC O104:H4 toward several E. coli strains, including serotype O157 strains, could be determined. Our study suggests that EHEC/EAEC O104:H4 is well adapted to the multiple adverse conditions occurring in fermented raw sausages. Therefore, it is strongly recommended that STEC strain cocktails composed of several serotypes, instead of E. coli O157:H7 alone, be used in food risk assessments. The enhanced persistence of EHEC/EAEC O104:H4 as a result of its robustness, as well as the production of bacteriocins, may account for its extraordinary virulence potential. In 2011, a severe outbreak caused by an EHEC/EAEC serovar O104:H4 strain led to many HUS sequelae. In this study, the persistence of the O104:H4 strain was compared with those of other outbreak-relevant STEC strains under conditions of fermented raw sausage production. Both O157:NM and O104:H4 strains could survive
77 FR 9888 - Shiga Toxin-Producing Escherichia coli

Science.gov (United States)

2012-02-21

... Toxin-Producing Escherichia coli in Certain Raw Beef Products AGENCY: Food Safety and Inspection Service... toxin-producing Escherichia coli (STEC) serogroups (O26, O45, O103, O111, O121, and O145). This new date..., that are contaminated with Shiga toxin-producing Escherichia coli (STEC) O26, O45, O103, O111, O121...
Microbiological assay method for sulfate by means of cultivation of Escherichia coli B(H). II. Determination of sulfur contents in orange leaves

Energy Technology Data Exchange (ETDEWEB)

Oba, H; Yamamoto, T; Iwamura, Y

1975-01-01

As one of the studies on the application of microbiological assay method for sulfate using E. coli B(H), determination of sulfur content in orange leaves was examined. Preparation of sample solution was as follows: dried orange leaves were subjected to combustion in the presence of Mg(NO/sub 3/)/sub 2/ x 6H/sub 2/O as an oxidizing agent at 800/sup 0/ for 1 hr. The residue was dissolved in 3 n HCl, neutralized with 3 n KOH, and the solution was passed through a column of Amberlite IR-120 (H/sup +/ form). The effluent was used for the microbiological assay, and the results obtained were as follows: (1) it was possible to determine sulfur content in orange leaves by microbiological assay method using Mg(NO/sub 3/)/sub 2/ x 6H/sub 2/O as an oxidizing agent; (2) this microbiological method gave small standard deviation (sigma = 3.8%) and accurate recovery (98.1-101.5%).; (3) this proposed microbiological method will make it possible to determine sulfur content in orange leaves with the amount of a sample less than that in the gravimetric method.
Lactobacillus proteins are associated with the bactericidal activity against E. coli of female genital tract secretions.

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Sabah Kalyoussef

Full Text Available Female genital tract secretions are bactericidal for Escherichia (E. coli ex vivo. However, the intersubject variability and molecules that contribute to this activity have not been defined.The bactericidal activity and concentration of immune mediators in cervicovaginal lavage (CVL collected from 99 healthy women were determined.CVL reduced the number of E. coli colonies by 68% [-26, 100] (median [range]. CVL were active against laboratory and clinical isolates of E. coli, but were inactive against Lactobacillus species. Bactericidal activity correlated with the concentration of protein recovered (p90% inhibitory activity (active and two with<30% activity were subjected to MS/MS proteomic analysis. 215 proteins were identified and six were found exclusively in active samples. Four of these corresponded to Lactobacillus crispatus or jensenii proteins. Moreover, culture supernatants from Lactobacillus jensenii were bactericidal for E. coli.Both host and commensal microbiota proteins contribute to mucosal defense. Identification of these proteins will facilitate the development of strategies to maintain a healthy vaginal microbiome and prevent colonization with pathogenic bacteria such as E. coli that increase the risk for urinary tract infections, preterm labor and perinatal infection.
Aberrant expression of sonic hedgehog pathway in colon cancer and melanosis coli.

Science.gov (United States)

Wang, Zhong Chuan; Gao, Jun; Zi, Shu Ming; Yang, Ming; Du, Peng; Cui, Long

2013-08-01

To determine the hedgehog (Hh) signaling pathway correlated with the development of colon cancer and melanosis coli. Protein and mRNA levels of Hh signaling pathway components (sonic hedgehog [Shh], protein patched homolog 1 [Ptch 1], GLI family zinc finger 1 [Gli 1] and suppressor of fused homolog [Drosophila] [Sufu]) in 127 patients with colon cancer, 36 with melanosis coli and 20 adjacent normal mucosal tissues taken from surgical specimens were evaluated using antibody staining and quantitative real-time polymerase chain reaction. In adjacent normal tissue Shh and Ptch1, but not Gli1 or Sufu, were weakly expressed and mainly in the lining epithelium of the colonic mucosa. In cancerous tissues Shh and Gli1 were uniformly strong while Ptch1 was patchy and weak, and Sufu uniformly weak, which paralleled their levels of corresponding mRNA. Elevated protein levels of Shh and Ptch were significantly associated with mucinous colonic tissues. Elevated Sufu protein levels were positively correlated with the diameter and invasion of the tumor. In patients with melanosis coli, mRNA levels of Shh, Ptch1, Gli1 and Sufu were very low, which was similar to those of adjacent normal tissues; but protein levels of Shh, Ptch1 and Gli1, but not Sufu, were high, which was similar to those of cancerous tissues. The mRNA and protein levels of Hh pathway components are aberrantly elevated in colon cancer, which may be the potential molecular classification markers. Further studies are required to determine the role of melanosis coli in the colon tumorigenesis. © 2013 The Authors. Journal of Digestive Diseases © 2013 Wiley Publishing Asia Pty Ltd and Chinese Medical Association Shanghai Branch, Chinese Society of Gastroenterology, Renji Hospital Affiliated to Shanghai Jiaotong University School of Medicine.
Frecuencia y patotipos de Escherichia coli diarrogénicas en niños peruanos con y sin diarrea Frequency and pathotypes of diarrheagenic Escherichia coli in peruvian children with and without diarrhea

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Theresa J. Ochoa

2011-03-01

Full Text Available Introducción. Las E. coli diarrogénicas (DEC son una de las principales causas de diarrea en niños en países en vías de desarrollo. Sin embargo, no son rutinariamente diagnosticadas en los laboratorios clínicos. Objetivos. Determinar la prevalencia de las DEC en niños peruanos y describir la variabilidad genética de estas cepas. Materiales y métodos. Se utilizaron 8 003 cepas de E. coli previamente aisladas de ocho estudios previos de diarrea en niños, mayormente en zonas periurbanas de Lima. El diagnóstico de las DEC fue a través de un PCR múltiple a tiempo real para los seis grupos de DEC. Se empleó PCR para la determinación de genes adicionales de virulencia. Resultados. La prevalencia promedio global en muestras de diarrea (n=4 243 fue: E. coli enteroagregativa (EAEC 9,9%, enteropatogénica (EPEC 8,5%, enterotoxigénica (ETEC 6,9%, difusamente adherente (DAEC 4,8%, productora de toxina shiga (STEC 0,8% y enteroinvasiva (EIEC 0,6%. La frecuencia relativa de cada patógeno varía según la edad y tipo de estudio. Los principales patotipos en muestras control (n=3 760 fueron EPEC (10,9% y EAEC (10,4%. Se encontró una gran variabilidad en la frecuencia de genes de virulencia para cada patotipo, así como en los mecanismos moleculares de resistencia, sin diferencias significativas entre muestras de diarrea y control. Conclusiones. Las DEC son causa importante de diarrea en niños peruanos. Estos patógenos son altamente heterogéneos. Se requieren estudios adicionales para determinar la prevalencia en zonas rurales del Perú, así como en casos graves de diarrea.Introduction. Diarrheagenic E. coli (DEC are a major cause of diarrhea in children in developing countries. However, they are not part of routine diagnosis in clinical laboratories. Objectives. To determine the DEC prevalence in Peruvian children and to describe the genetic variability of these strains. Materials and methods. A total of 8 003 E. coli strains previously
Synthesis of avenanthramides using engineered Escherichia coli.

Science.gov (United States)

Lee, Su Jin; Sim, Geun Young; Kang, Hyunook; Yeo, Won Seok; Kim, Bong-Gyu; Ahn, Joong-Hoon

2018-03-22

Hydroxycinnamoyl anthranilates, also known as avenanthramides (avns), are a group of phenolic alkaloids with anti-inflammatory, antioxidant, anti-itch, anti-irritant, and antiatherogenic activities. Some avenanthramides (avn A-H and avn K) are conjugates of hydroxycinnamic acids (HC), including p-coumaric acid, caffeic acid, and ferulic acid, and anthranilate derivatives, including anthranilate, 4-hydroxyanthranilate, and 5-hydroxyanthranilate. Avns are primarily found in oat grain, in which they were originally designated as phytoalexins. Knowledge of the avns biosynthesis pathway has now made it possible to synthesize avns through a genetic engineering strategy, which would help to further elucidate their properties and exploit their beneficial biological activities. The aim of the present study was to synthesize natural avns in Escherichia coli to serve as a valuable resource. We synthesized nine avns in E. coli. We first synthesized avn D from glucose in E. coli harboring tyrosine ammonia lyase (TAL), 4-coumarate:coenzyme A ligase (4CL), anthranilate N-hydroxycinnamoyl/benzoyltransferase (HCBT), and anthranilate synthase (trpEG). A trpD deletion mutant was used to increase the amount of anthranilate in E. coli. After optimizing the incubation temperature and cell density, approximately 317.2 mg/L of avn D was synthesized. Avn E and avn F were then synthesized from avn D, using either E. coli harboring HpaBC and SOMT9 or E. coli harboring HapBC alone, respectively. Avn A and avn G were synthesized by feeding 5-hydroxyanthranilate or 4-hydroxyanthranilate to E. coli harboring TAL, 4CL, and HCBT. Avn B, avn C, avn H, and avn K were synthesized from avn A or avn G, using the same approach employed for the synthesis of avn E and avn F from avn D. Using different HCs, nine avns were synthesized, three of which (avn D, avn E, and avn F) were synthesized from glucose in E. coli. These diverse avns provide a strategy to synthesize both natural and unnatural avns
Distribution of Diverse Escherichia coli between Cattle and Pasture

OpenAIRE

NandaKafle, Gitanjali; Seale, Tarren; Flint, Toby; Nepal, Madhav; Venter, Stephanus N.; Brözel, Volker S.

2017-01-01

Escherichia coli is widely considered to not survive for extended periods outside the intestines of warm-blooded animals; however, recent studies demonstrated that E. coli strains maintain populations in soil and water without any known fecal contamination. The objective of this study was to investigate whether the niche partitioning of E. coli occurs between cattle and their pasture. We attempted to clarify whether E. coli from bovine feces differs phenotypically and genotypically from isola...

Antimicrobial Resistance Pattern in Escherichia coli Isolates Obtained from a Specialized Women and Children Hospital in Shiraz, Iran: A Prevalence Study

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Mahtab Hadadi

2016-10-01

Full Text Available Abstract Background: Escherichia coli, known as a clinically significant bacteria, can cause a wide range of infections, including urinary tract infections (UTIs, blood stream infections (BSIs, and can frequently be isolated from various clinical specimens. Evaluation of antimicrobial resistant pattern is a necessary action, especially about such bacteria which are frequent and life threatening. The aim of this study was to determine the frequency and antimicrobial resistance pattern of E. coli isolates obtained from various clinical specimens. Methods: This retrospective study was performed within a seven month period from January 2015 to August 2015 at a specialized women and children hospital in Shiraz, Iran. E. coli isolates were obtained from various clinical specimens and identified using standard microbiological procedure. Antimicrobial susceptibility patterns were determined using disk diffusion method in accordance with CLSI recommendation. Results: Of the total 130 positive cultures, the majority of E. coli isolates were obtained from urine (96=73.8% and blood (11=8.5% specimens. Overall, gentamicin (70.8% was the effective antibiotic for the tested E. coli isolates. E. coli isolates obtained from urine specimens showed the highest resistance rates against ampicillin (84.4% and nalidixic acid (61.5%; while they showed the most sensitivity to gentamicin (79.2%, nitrofurantoin (70.8% and ciprofloxacin (66.7%. Moreover, the highest antibiotic resistance rates belonged to the isolates recovered from endotracheal tube (ETT. Conclusion: The results showed that gentamicin was the most effective antibiotic against E. coli infections. However, in addition to the gentamicin, we can recommend nitrofurantoin and ciprofloxacin as the other effective agents for UTIs
PART I. ESCHERICHIA COLI

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Sanaa Mahdi Oraibi

2016-11-01

Full Text Available The presence of Escherichia coli in the air of facilities involved in management and composting of post-slaughter poultry wastes in selected plants of West Western Pomerania region was studied. Measurements were made on four dates in a variety of weather conditions during the year. The study was conducted at 5 objects that differ in the type of waste and the degree of preparation for composting. These were: chemical treatment and preliminary processing plant, liquid wastes reservoir, platform for preparation of materials for composting, storage of biological sediments, and composting facility. Measurement of bacteria count was carried out in accordance with the applicable procedures on selective chromogenic TBX medium. The assays revealed the presence of E. coli at all test objects, but not always on all measurement dates. It has been shown that the presence of E. coli was from 20 to 3047 CFU∙m-3 of air, although the largest quantities were most frequently detected in the air of the building for post-slaughter waste pre-treatment in chemical treatment plant.
Effect of visible light on progressive dormancy of Escherichia coli cells during the survival process in natural fresh water

International Nuclear Information System (INIS)

Barcina, I.; Gonzalez, J.M.; Iriberri, J.; Egea, L.

1989-01-01

Some effects of visible light on the survival of Escherichia coli in waters of the Butron river were studied by comparing illuminated and nonilluminated systems. The following count methods were used: CFU on a selective medium (eosin-methylene blue agar), CFU on a medium of recuperation (Trypticase soy agar with yeast extract and glucose), number of metabolically active cells by reduction of 2-(p-iodophenyl)-3-(p-nitrophenyl)-5-phenyl tetrazolium chloride (INT) to INT-formazan, and total number of E. coli cells as determined by the acridine orange direct-count method. In the illuminated systems, decreases in CFU of E. coli and in the number of metabolically active cells were observed. However, no decline of the total number of E. coli cells was observed. By count methods, different stages of progressive dormancy of E. coli cells were determined to exist in illuminated systems. Culturable and recoverable cells were defined as viable cells, and metabolically active cells and morphologically intact cells were defined as somnicells. Indirect activity measurements were also done by using [14C]glucose. In illuminated systems, a decrease of glucose uptake by E. coli cells was observed throughout the experiments. The assimilated fraction of [14C]glucose decreased faster than the respired fraction in illuminated systems. The percentage of respired [14C]glucose (14CO2 production) with respect to the total glucose uptake increased throughout the experiments, and the percentage of assimilated glucose decreased. Therefore, the visible light was also responsible for an additional inhibition of biosynthetic processes
THE ANTIBACTERIAL ACTIVITY OF WATER APPLE LEAVES ACTIVE COMPOUND (Syzygium zeylanicum AGAINST Escherichia coli AND Staphylococcus aureus

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- Hamidah

2017-07-01

Full Text Available Escherichia coli is one of the bacteria that cause infections in the human digestive tract such as diarrhea, while Staphylococcus aureus is one of the bacteria that cause infections in the skin injury such as boils and pimples. This study used Syzygium zeylanicum leaves because it has potential as a antibacterial because it contains active compounds. This study aimed was determine the antibacterial activity of the fraction and the active compound in Syzygium zeylanicum leaves against Escherichia coli and Staphylococcus aureus. Research conducted on November 2015 to January 2016. The method used in this research were extraction by maceration, fractionation by liquid fractionation, antibacterial activity test, and determination of minimum inhibitory concentration with the diffusion method and isolation of active compounds by column chromatography method. The bacteria used in this test are Escherichia coli and Staphylococcus aureus. Data are presented in tabular form based on the average value of the inhibition diameter and deviation standard. The results of this research showed the water methanol active fraction against the bacteria that used in this test. The methanol water fraction had obtained one antibacterial compound in bottle 1,3,5 which shows the value of tannin Rf 0,416. The minimum inhibitory concentration of water methanol of water apple leaves is 1000 µg/mL for Escherichia coli and 500 µg/mL for Staphylococcus aureus. The minimum inhibitory concentration of the active compound to Escherichia coli and Staphylococcus aureus in 500 µg/mL. The fraction and the active compound of water apple leaves have an antibacterial activity with Escherichia coli and Staphylococcus aureus and the active compound is tannin.
Probable secondary transmission of antimicrobial-resistant Escherichia coli between people living with and without pets.

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Chung, Yeon Soo; Park, Young Kyung; Park, Yong Ho; Park, Kun Taek

2017-03-18

Companion animals are considered as one of the reservoirs of antimicrobial-resistant (AR) bacteria that can be cross-transmitted to humans. However, limited information is available on the possibility of AR bacteria originating from companion animals being transmitted secondarily from owners to non-owners sharing the same space. To address this issue, the present study investigated clonal relatedness among AR E. coli isolated from dog owners and non-owners in the same college classroom or household. Anal samples (n=48) were obtained from 14 owners and 34 non-owners; 31 E. coli isolates were collected (nine from owners and 22 from non-owners). Of 31 E. coli, 20 isolates (64.5%) were resistant to at least one antimicrobial, and 16 isolates (51.6%) were determined as multi-drug resistant E. coli. Six isolates (19.4%) harbored integrase genes (five harbored class I integrase gene and one harbored class 2 integrase gene, respectively). Pulsed-field gel electrophoretic analysis identified three different E. coli clonal sets among isolates, indicating that cross-transmission of AR E. coli can easily occur between owners and non-owners. The findings emphasize a potential risk of spread of AR bacteria originating from pets within human communities, once they are transferred to humans. Further studies are needed to evaluate the exact risk and identify the risk factors of secondarily transmission by investigating larger numbers of isolates from pets, their owners and non-owners in a community.
Identification of enteropathogenic Escherichia coli in children with acute diarrheic syndrome from Sucre State, Venezuela.

Science.gov (United States)

Michelli, Elvia; Millán, Adriana; Rodulfo, Hectorina; Michelli, Mirian; Luiggi, Jesús; Carreño, Numirin; De Donato, Marcos

2016-03-28

Diarrheagenic Escherichia coli is an important causative agent of acute diarrheic syndrome. To identify clonal groups of enteropathogenic E. coli (EPEC), in 485 children with acute diarrhea aged 0 to 10 years attending health care centers in Arismendi, Benítez and Sucre municipalities, Sucre state, Venezuela, from March to December, 2011. After obtaining the informed consent, stool samples were collected. Escherichia coli was identified using standard coproculture methods and serology with polyvalent and monovalent antisera. DNA was isolated, and eae (intimin) and bfpA (bundlin) genes were amplified through two multiplex polymerase chain reactions (PCR). The presence of bacterial infection was determined in 39.6% of coprocultures. The prevalence of E. coli was 54.7%; 82.9% of these isolates were positive by serology for the evaluated serogroups and serotypes, which were mostly identified in children between 0 and 2 years (37.9%); 48.6% of E. coli strains amplified the eae gene; of these, 58.8% were classified as typical EPEC (eae+ y bfp+). EPEC II was the most common serogroup (38.7%), with predominance of typical EPEC (60%). In positive strains for eae gene, the β intimin allele was the most frequently identified (74.5%). Only four strains with O157:H7 serotype were identified, which showed no PCR amplification of the eae and bfpA genes. This study showed the importance of molecular tests to identify diarrheagenic E. coli strains causing clinical conditions of varying severity.
Phylogenetic analysis of Escherichia coli isolates from healthy and diarrhoeic calves in Mashhad, Iran

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M. Barzan

2017-03-01

Full Text Available Escherichia coli is a normal inhabitant of the gastrointestinal tract of vertebrates. Certain Escherichia coli strains have been associated with neonatal diarrhoea in ruminants. These strains can be assigned to one of the four main phylogenetic groups, A, B1, B2 and D. Several studies have shown the rela-tionship between phylogeny and pathogenicity of E. coli, a great deal can be obtained by determining the phylogroup of unknown E. coli strains. In this study, we aimed to evaluate the influence of diar-rhoea on the genetic composition of E. coli populations isolated from calves. A total of 80 Es-cherichia coli isolates were obtained from healthy and diarrhoeic calves. Phylogenetic grouping was done based on the Clermont triplex PCR method using primers targeted at three genetic markers, chuA, yjaA and TspE4.C2. According to our results, phylogenetic group A strains was the most prevalent in both healthy (37.5% and diarrhoeic calves (55%. Group B1 contained 27.5% of isolates in healthy calves, followed by group B2 (17.5%, and group D (7.5%. Also, four isolates from healthy calves were not included in the major phylogenetic groups or subgroups. A total of 14% and 4% of isolates from diarrhoeic calves beloned to phylogroups B2 and D respectively. Although no isolate from diarrhoeic calves was found to belong to group B1, there was no significant difference between healthy and diarrhoeic calves for other phylogroups. There was not a dramatic shift in E. coli phylogroup/subgroup due to occurrence of diarrhoea in calves, except for phylogroup B1 which was higher in healthy calves. This can be due to the difference in secretions of digestive system in diarrhoeic calves which can prevent the conditions for instability of Escherichia coli isolates of phy-logroup B1. The majority of isolates from both healthy and diarrhoeic calves belonged to non-pathogenic phylogentic group A and B1.
Screening of antibacterial effect of the Scrophularia Striata against E. coli in vitro

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Sharafati-chaleshtori Reza

2014-01-01

Full Text Available Introduction: This study was aimed to evaluate the antimicrobial activity of the ethanol and aqueous extracts of Scrophularia striata plant on E. coli O157:H7 in vitro. Methods: In this experimental study the ethanol and aqueous extract of the plant was prepared and their antibacterial effects were determined using sink diffusion and broth macrodilution methods against the bacterium E. coli O157:H7. Results: The ethanol extract of Scrophularia striata plant had inhibitory effect on the E. coli O157:H7 in two methods of sink diffusion and macrodilution, but the aqueous extract of this plant had not antibacterial effect. The MIC and MBC amounts were obtained 90mg/ml and 100 mg/ml, respectively. Conclusion: Based on the present results that the ethanol extract of the Scrophularia Striata plant showed inhibitory effect on bacterium, more researches are recommended to evaluate its in vivo effects and to identify active compounds.
Triosephosphate isomerase is a common crystallization contaminant of soluble His-tagged proteins produced in Escherichia coli

International Nuclear Information System (INIS)

Kozlov, Guennadi; Vinaik, Roohi; Gehring, Kalle

2013-01-01

Crystals of E. coli triosephosphate isomerase were obtained as a contaminant and its structure was determined to 1.85 Å resolution. Attempts to crystallize several mammalian proteins overexpressed in Escherichia coli revealed a common contaminant, triosephosphate isomerase, a protein involved in glucose metabolism. Even with triosephosphate isomerase present in very small amounts, similarly shaped crystals appeared in the crystallization drops in a number of polyethylene glycol-containing conditions. All of the target proteins were His-tagged and their purification involved immobilized metal-affinity chromatography (IMAC), a step that was likely to lead to triosephosphate isomerase contamination. Analysis of the triosephosphate isomerase crystals led to the structure of E. coli triosephosphate isomerase at 1.85 Å resolution, which is a significant improvement over the previous structure
Determining Thermal Inactivation of Escherichia coli O157:H7 in Fresh Compost by Simulating Early Phases of the Composting Process ▿

OpenAIRE

Singh, Randhir; Kim, Jinkyung; Shepherd, Marion W.; Luo, Feng; Jiang, Xiuping

2011-01-01

A three-strain mixture of Escherichia coli O157:H7 was inoculated into fresh dairy compost (ca. 107 CFU/g) with 40 or 50% moisture and was placed in an environmental chamber (ca. 70% humidity) that was programmed to ramp from room temperature to selected composting temperatures in 2 and 5 days to simulate the early composting phase. The surviving E. coli O157:H7 population was analyzed by direct plating and enrichment. Optimal and suboptimal compost mixes, with carbon/nitrogen (C/N) ratios of...
Effects of Escherichia coli on mixotrophic growth of Chlorella minutissima and production of biofuel precursors.

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Brendan T Higgins

Full Text Available Chlorella minutissima was co-cultured with Escherichia coli in airlift reactors under mixotrophic conditions (glucose, glycerol, and acetate substrates to determine possible effects of bacterial contamination on algal biofuel production. It was hypothesized that E. coli would compete with C. minutissima for nutrients, displacing algal biomass. However, C. minutissima grew more rapidly and to higher densities in the presence of E. coli, suggesting a symbiotic relationship between the organisms. At an initial 1% substrate concentration, the co-culture produced 200-587% more algal biomass than the axenic C. minutissima cultures. Co-cultures grown on 1% substrate consumed 23-737% more of the available carbon substrate than the sum of substrate consumed by E. coli and C. minutissima alone. At 1% substrate, total lipid and starch productivity were elevated in co-cultures compared to axenic cultures indicating that bacterial contamination was not detrimental to the production of biofuel precursors in this specific case. Bio-fouling of the reactors observed in co-cultures and acid formation in all mixotrophic cultures, however, could present challenges for scale-up.
Copper Homeostasis in Escherichia coli and Other Enterobacteriaceae.

Science.gov (United States)

Rensing, Christopher; Franke, Sylvia

2007-04-01

An interesting model for studying environmental influences shaping microbial evolution is provided by a multitude of copper resistance and copper homeostasis determinants in enteric bacteria. This review describes these determinants and tries to relate their presence to the habitat of the respective organism, as a current hypothesis predicts that the environment should determine an organism's genetic makeup. In Escherichia coli there are four regulons that are induced in the presence of copper. Two, the CueR and the CusR regulons, are described in detail. A central component regulating intracellular copper levels, present in all free-living enteric bacteria whose genomes have so far been sequenced, is a Cu(I)translocating P-type ATPase. The P-type ATPase superfamily is a ubiquitous group of proteins involved in the transport of charged substrates across biological membranes. Whereas some components involved in copper homeostasis can be found in both anaerobes and aerobes, multi-copper oxidases (MCOs) implicated in copper tolerance in E. coli, such as CueO and the plasmid-based PcoA, can be found only in aerobic organisms. Several features indicate that CueO, PcoA, and other related MCOs are specifically adapted to combat copper-mediated oxidative damage. In addition to these well-characterized resistance operons, there are numerous other genes that appear to be involved in copper binding and trafficking that have not been studied in great detail. SilE and its homologue PcoE, for example, are thought to effect the periplasmic binding and sequestration of silver and copper, respectively.
Effect of addition of organic waste on reduction of Escherichia coli during cattle feces composting under high-moisture condition.

Science.gov (United States)

Hanajima, Dai; Kuroda, Kazutaka; Fukumoto, Yasuyuki; Haga, Kiyonori

2006-09-01

To ensure Escherichia coli reduction during cattle feces composting, co-composting with a variety of organic wastes was examined. A mixture of dairy cattle feces and shredded rice straw (control) was blended with organic wastes (tofu residue, rice bran, rapeseed meal, dried chicken feces, raw chicken feces, or garbage), and composted using a bench-scale composter under the high-moisture condition (78%). The addition of organic waste except chicken feces brought about maximum temperatures of more than 55 degrees C and significantly reduced the number of E. coli from 10(6) to below 10(2)CFU/g-wet after seven days composting, while in the control treatment, E. coli survived at the same level as that of raw feces. Enhancements of the thermophilic phase and E. coli reduction were related to the initial amount of easily digestible carbon in mass determined as BOD. BOD value more than 166.2 mg O2/DMg brought about significant E. coli reduction.
Colonization of Enteroaggregative Escherichia coli and Shiga toxin-producing Escherichia coli in chickens and humans in southern Vietnam

NARCIS (Netherlands)

Trung, Nguyen Vinh; Nhung, Hoang Ngoc; Carrique-Mas, Juan J.; Mai, Ho Huynh; Tuyen, Ha Thanh; Campbell, James; Nhung, Nguyen Thi; van Minh, Pham; Wagenaar, Jaap A.; Mai, Nguyen Thi Nhu; Hieu, Thai Quoc; Schultsz, Constance; Hoa, Ngo Thi

2016-01-01

Enteroaggregative (EAEC) and Shiga-toxin producing Escherichia coli (STEC) are a major cause of diarrhea worldwide. E. coli carrying both virulence factors characteristic for EAEC and STEC and producing extended-spectrum beta-lactamase caused severe and protracted disease during an outbreak of E.
Impact of antibiotic restriction on resistance levels of Escherichia coli

DEFF Research Database (Denmark)

Boel, Jonas; Andreasen, Viggo; Jarløv, Jens Otto

2016-01-01

as a retrospective controlled interrupted time series (ITS) at two university teaching hospitals, intervention and control, with 736 and 552 beds, respectively. The study period was between January 2008 and September 2014. We used ITS analysis to determine significant changes in antibiotic use and resistance levels......% CI -177, -126)] and fluoroquinolones [-44.5 DDDs/1000 bed-days (95% CI -58.9, -30.1)]. Resistance of E. coli showed a significant change in slope for cefuroxime [-0.13 percentage points/month (95% CI -0.21, -0.057)] and ciprofloxacin [-0.15 percentage points/month (95% CI -0.26, -0.038)]. CONCLUSIONS......OBJECTIVES: We evaluated the effect of an antibiotic stewardship programme (ASP) on the use of antibiotics and resistance levels of Escherichia coli using a method that allowed direct comparison between an intervention hospital and a control hospital. METHODS: The study was conducted...
Survival of pathogenic Escherichia coli on basil, lettuce, and spinach

Science.gov (United States)

The contamination of lettuce, spinach and basil with pathogenic E. coli has caused numerous illnesses over the past decade. E. coli O157:H7, E. coli O104:H4 and avian pathogenic E. coli (APECstx- and APECstx+) were inoculated on basil plants and in promix soiless substrate using drip and overhead ir...
[Changes of biological behavioral of E. coli K1 after ppk1 gene deletion].

Science.gov (United States)

Peng, Liang; Pan, Jiayun; Luo, Su; Yang, Zhenghui; Huang, Mufang; Cao, Hong

2014-06-01

To study the changes in biological behaviors of meningitis E. coli K1 strain E44 after deletion of polyphosphate kinase 1 (ppk1) gene and explore the role of ppk1 in the pathogenesis of E. coli K1-induced meningitis. The wild-type strain E. coli K1 and ppk1 deletion mutant were exposed to heat at 56 degrees celsius; for 6 min, and their survival rates were determined. The adhesion and invasion of the bacteria to human brain microvascular endothelial cells (HBMECs) were observed using electron microscopy and quantitative tests. HBMECs were co-incubated with wild-type strain or ppk1 deletion mutant, and the cytoskeleton rearrangement was observed under laser scanning confocal microscope. The survival rate of the ppk1 deletion mutant was significantly lower than that of the wild-type strain after heat exposure. The ppk1 deletion mutant also showed lowered cell adhesion and invasion abilities and weakened ability to induce cytoskeleton rearrangement in HBMECs. ppk1 gene is important for E.coli K1 for heat resistance, cell adhesion and invasion, and for inducing cytoskeletal rearrangement in HBMECs.
Inactivation of Escherichia coli inoculated onto fresh-cut chopped cabbage using electron-beam processing.

Science.gov (United States)

Grasso, Elizabeth M; Uribe-Rendon, Roberto M; Lee, Ken

2011-01-01

During the past decade there were more than 50 reported outbreaks involving leafy green vegetables contaminated with foodborne pathogens. Leafy greens, including cabbage, are fresh foods rarely heated before consumption, which enables foodborne illness. The need for improved safety of fresh food drives the demand for nonthermal food processes to decrease the risk of pathogens while maintaining fresh quality. This study examines the efficacy of electron-beam (e-beam) irradiation in decreasing indigenous microflora on fresh-cut cabbage and determines the optimal dosage to pasteurize fresh-cut cabbage inoculated with Escherichia coli K-12. Fresh-cut cabbage (100 g) was inoculated with ∼8 log E. coli K-12 and e-beam irradiated at doses of 0, 1.0, 2.3, or 4.0 kGy. At 2.3 kGy there was 7-log reduction of E. coli K-12 in the fresh-cut cabbage. The D(10)-value for E. coli K-12 in fresh-cut cabbage was 0.564 kGy. E-beam irradiation is thus a viable nonthermal treatment that extends the shelf life and increases the safety of fresh cabbage by reducing or eliminating indigenous microflora and unwanted pathogens.
Production of caffeoylmalic acid from glucose in engineered Escherichia coli.

Science.gov (United States)

Li, Tianzhen; Zhou, Wei; Bi, Huiping; Zhuang, Yibin; Zhang, Tongcun; Liu, Tao

2018-07-01

To achieve biosynthesis of caffeoylmalic acid from glucose in engineered Escherichia coli. We constructed the biosynthetic pathway of caffeoylmalic acid in E. coli by co-expression of heterologous genes RgTAL, HpaBC, At4CL2 and HCT2. To enhance the production of caffeoylmalic acid, we optimized the tyrosine metabolic pathway of E. coli to increase the supply of the substrate caffeic acid. Consequently, an E. coli-E. coli co-culture system was used for the efficient production of caffeoylmalic acid. The final titer of caffeoylmalic acid reached 570.1 mg/L. Microbial production of caffeoylmalic acid using glucose has application potential. In addition, microbial co-culture is an efficient tool for producing caffeic acid esters.
Secretory expression of nattokinase from Bacillus subtilis YF38 in Escherichia coli.

Science.gov (United States)

Liang, Xiaobo; Jia, Shifang; Sun, Yufang; Chen, Meiling; Chen, Xiuzhu; Zhong, Jin; Huan, Liandong

2007-11-01

Nattokinase producing bacterium, B. subtilis YF38, was isolated from douchi, using the fibrin plate method. The gene encoding this enzyme was cloned by polymerase chain reaction (PCR). Cytoplasmic expression of this enzyme in E. coli resulted in inactive inclusion bodies. But with the help of two different signal peptides, the native signal peptide of nattokinase and the signal peptide of PelB, active nattokinase was successfully expressed in E. coli with periplasmic secretion, and the nattokinase in culture medium displayed high fibrinolytic activity. The fibrinolytic activity of the expressed enzyme in the culture was determined to reach 260 urokinase units per micro-liter when the recombinant strain was induced by 0.7 mmol l(-1) isopropyl-beta-D- thiogalactopyranoside (IPTG) at 20 degrees C for 20 h, resulting 49.3 mg active enzyme per liter culture. The characteristic of this recombinant nattokinase is comparable to the native nattokinase from B. subtilis YF38. Secretory expression of nattokinase in E. coli would facilitate the development of this enzyme into a therapeutic product for the control and prevention of thrombosis diseases.

Rapid selection of quinolone resistance in Campylobacter jejuni but not in Escherichia coli in individually housed broilers

NARCIS (Netherlands)

Boven, van R.M.; Veldman, K.T.; Jong, de M.C.M.; Mevius, D.J.

2003-01-01

Objective: To determine the within-host population dynamics of Campylobacter jejuni and Escherichia coli in chickens during and after treatment with fluoroquinolones. Materials and methods: Total and resistant faecal counts were determined from cloacal swabs during and after treatment with
Interaction of Escherichia coli with growing salad spinach plants.

Science.gov (United States)

Warriner, Keith; Ibrahim, Faozia; Dickinson, Matthew; Wright, Charles; Waites, William M

2003-10-01

In this study, the interaction of a bioluminescence-labeled Escherichia coli strain with growing spinach plants was assessed. Through bioluminescence profiles, the direct visualization of E. coli growing around the roots of developing seedlings was accomplished. Subsequent in situ glucuronidase (GUS) staining of seedlings confirmed that E. coli had become internalized within root tissue and, to a limited extent, within hypocotyls. When inoculated seeds were sown in soil microcosms and cultivated for 42 days, E. coli was recovered from the external surfaces of spinach roots and leaves as well as from surface-sterilized roots. When 20-day-old spinach seedlings (from uninoculated seeds) were transferred to soil inoculated with E. coli, the bacterium became established on the plant surface, but internalization into the inner root tissue was restricted. However, for seedlings transferred to a hydroponic system containing 10(2) or 10(3) CFU of E. coli per ml of the circulating nutrient solution, the bacterium was recovered from surface-sterilized roots, indicating that it had been internalized. Differences between E. coli interactions in the soil and those in the hydroponic system may be attributed to greater accessibility of the roots in the latter model. Alternatively, the presence of a competitive microflora in soil may have restricted root colonization by E. coli. The implications of this study's findings with regard to the microbiological safety of minimally processed vegetables are discussed.
Behaviour of four diarrheagenic Escherichia coli pathotypes on carrots and in unpasteurized carrot juice.

Science.gov (United States)

Gómez-Aldapa, C A; Torres-Vitela, M Del R; Acevedo-Sandoval, O A; Rangel-Vargas, E; Villarruel-López, A; Castro-Rosas, J

2013-12-01

The behaviours of Shiga toxin-producing Escherichia coli (STEC), enteroinvasive E. coli (EIEC), enteropathogenic E. coli (EPEC) and enterotoxigenic E. coli (ETEC) strains on raw carrots at 3 ± 1 and 30 ± 1°C, and in unpasteurized carrot juice at 3 ± 1, 12 ± 1, 20 ± 1, 30 ± 1°C and 37 ± 1°C were determined. Raw carrots were purchased in a local market. Fresh juice was obtained from raw carrots in the laboratory. On whole carrots stored at 30 ± 1 or 3 ± 1°C, no growth was observed for any of the diarrheagenic E. coli pathotype (DEPs) strains studied. After 15 days at 30 ± 1°C, the tested DEPs had decreased from an initial inoculum level of approximately 6 log colony-forming units (CFU) to approximately 3·5 log CFU on whole carrots, while at 3 ± 1°C, they decreased from approximately 2·4 log to 1·6 log CFU. All these DEPs grew in fresh carrot juice at 12 ± 1, 20 ± 1, 30 ± 1 and 37 ± 1°C, reaching counts of approximately 4·2 log, 5·8 log, 6·7 log and 7·5 log CFU ml(-1) , respectively, after 24 h. At 3 ± 1°C, the DEP growth was inhibited at least during 7 days. Thus, storage of carrot juice at unrefrigerated temperatures can result in DEP growth to levels likely to represent a risk to consumers. The information presented shows the potential of Shiga toxin-producing Escherichia coli, enteroinvasive E. coli, enteropathogenic E. coli and enterotoxigenic E. coli strains for survival on carrots and growth in carrot juice at warmer temperatures. The information can help food processors in plants and restaurants understand the importance of the implementation of hazard analysis and critical control point (HACCP) strategies for preventing potential diarrheagenic E. coli pathotypes (DEPs) contamination and growth in carrot juice. This is the first report regarding the behaviour these DEPs on carrots and in carrot juice. © 2013 The Society for Applied Microbiology.
Clonal study of avian Escherichia coli strains by fliC conserved-DNA-sequence regions analysis Estudo clonal de Escherichia coli aviário por análise de seqüências de DNA conservadas do gene fliC

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Tatiana Amabile de Campos

2008-10-01

Full Text Available The clonal relationship among avian Escherichia coli strains and their genetic proximity with human pathogenic E. coli, Salmonela enterica, Yersinia enterocolitica and Proteus mirabilis, was determined by the DNA sequencing of the conserved 5' and 3'regions fliC gene (flagellin encoded gene. Among 30 commensal avian E. coli strains and 49 pathogenic avian E. coli strains (APEC, 24 commensal and 39 APEC strains harbored fliC gene with fragments size varying from 670bp to 1,900bp. The comparative analysis of these regions allowed the construction of a dendrogram of similarity possessing two main clusters: one compounded mainly by APEC strains and by H-antigens from human E. coli, and another one compounded by commensal avian E. coli strains, S. enterica, and by other H-antigens from human E. coli. Overall, this work demonstrated that fliC conserved regions may be associated with pathogenic clones of APEC strains, and also shows a great similarity among APEC and H-antigens of E. coli strains isolated from humans. These data, can add evidence that APEC strains can exhibit a zoonotic risk.A relação clonal entre linhagens de Escherichia coli de origem aviária e sua proximidade genética com E. coli patogênica para humanos, Salmonella enterica, Yersinia enterocolitica e Proteus mirabilis foi determinada através da utilização das seqüências conservadas 5' e 3' do gene fliC (responsável pela codificação da flagelina. Entre as 30 linhagens comensais de E. coli aviária e as 49 linhagens patogênicas de E. coli para aves (APEC, 24 linhagens comensais e 39 APEC apresentaram o gene fliC, que foi encontrado em tamanhos que variam de 670pb a 1900pb. Um dendrograma representando similaridade genética foi obtido a partir do seqüenciamento das regiões 5' e 3' conservadas do gene fliC das linhagens de E. coli de origem aviária, das seqüências dos antígenos H de E. coli de origem humana, de S. enterica, Y. enterocolitica e de P. mirabilis. A an
A scoping study on the prevalence of Escherichia coli and ...

African Journals Online (AJOL)

In the Eastern Cape Province E. coli and enterococci were detected in 7 and 4 of the 15 RHRW tanks, respectively. Enterococci were detected only from one river whereas E. coli was detected in all three rivers; in spring water neither enterococci nor E. coli were detected. Samples from GRWH tanks were positive for E. coli ...
Asymptomatic bacteriuria Escherichia coli are live biotherapeutics for UTI.

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Rudick, Charles N; Taylor, Aisha K; Yaggie, Ryan E; Schaeffer, Anthony J; Klumpp, David J

2014-01-01

Urinary tract infections (UTI) account for approximately 8 million clinic visits annually with symptoms that include acute pelvic pain, dysuria, and irritative voiding. Empiric UTI management with antimicrobials is complicated by increasing antimicrobial resistance among uropathogens, but live biotherapeutics products (LBPs), such as asymptomatic bacteriuria (ASB) strains of E. coli, offer the potential to circumvent antimicrobial resistance. Here we evaluated ASB E. coli as LBPs, relative to ciprofloxacin, for efficacy against infection and visceral pain in a murine UTI model. Visceral pain was quantified as tactile allodynia of the pelvic region in response to mechanical stimulation with von Frey filaments. Whereas ciprofloxacin promoted clearance of uropathogenic E. coli (UPEC), it did not reduce pelvic tactile allodynia, a measure of visceral pain. In contrast, ASB E. coli administered intravesically or intravaginally provided comparable reduction of allodynia similar to intravesical lidocaine. Moreover, ASB E. coli were similarly effective against UTI allodynia induced by Proteus mirabilis, Enterococccus faecalis and Klebsiella pneumoniae. Therefore, ASB E. coli have anti-infective activity comparable to the current standard of care yet also provide superior analgesia. These studies suggest that ASB E. coli represent novel LBPs for UTI symptoms.
Modeling the inactivation of Escherichia coli 0157:H7 and uropathogenic E.coli in ground chicken by high pressure processing and thymol

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Disease causing Escherichia coli commonly found in meat and poultry include intestinal pathogenic E. coli (iPEC) as well as extraintestinal types such as the Uropathogenic E. coli (UPEC). In this study we compare the resistance of iPEC (O157:H7) to UPEC in chicken meat using High Pressure Processing...
Modeling the inactivatin of Escherichia coli 0157:H7 and uropathogenic E. coli in ground beef by high pressure processing and citral

Science.gov (United States)

Disease causing Escherichia coli commonly found in meat and poultry include intestinal pathogenic E. coli (iPEC) as well as extraintestinal types such as the Uropathogenic E. coli (UPEC). In this study we compared the resistance of iPEC (O157:H7) to UPEC in ground beef using High Pressure Processing...
Complete Genome Sequence of Escherichia coli Strain WG5

DEFF Research Database (Denmark)

Imamovic, Lejla; Misiakou, Maria-Anna; van der Helm, Eric

2018-01-01

Escherichia coli strain WG5 is a widely used host for phage detection, including somatic coliphages employed as standard ISO method 10705-1 (2000). Here, we present the complete genome sequence of a commercial E. coli WG5 strain.......Escherichia coli strain WG5 is a widely used host for phage detection, including somatic coliphages employed as standard ISO method 10705-1 (2000). Here, we present the complete genome sequence of a commercial E. coli WG5 strain....
Environmental Escherichia coli: Ecology and public health implications - A review

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Jang, Jeonghwan; Hur, Hor-Gil; Sadowsky, Michael J.; Byappanahalli, Muruleedhara; Yan, Tao; Ishii, Satoshi

2017-01-01

Escherichia coli is classified as a rod-shaped, Gram-negative bacterium in the family Enterobacteriaceae. The bacterium mainly inhabits the lower intestinal tract of warm-blooded animals, including humans, and is often discharged into the environment through feces or wastewater effluent. The presence of E. coli in environmental waters has long been considered as an indicator of recent fecal pollution. However, numerous recent studies have reported that some specific strains of E. coli can survive for long periods of time, and potentially reproduce, in extra-intestinal environments. This indicates that E. coli can be integrated into indigenous microbial communities in the environment. This naturalization phenomenon calls into question the reliability of E. coli as a fecal indicator bacterium (FIB). Recently, many studies reported that E. coli populations in the environment are affected by ambient environmental conditions affecting their long-term survival. Large-scale studies of population genetics provide the diversity and complexity of E. coli strains in various environments, affected by multiple environmental factors. This review examines the current knowledge on the ecology of E. coli strains in various environments in regards to its role as a FIB and as a naturalized member of indigenous microbial communities. Special emphasis is given on the growth of pathogenic E. coli in the environment, and the population genetics of environmental members of the genus Escherichia. The impact of environmental E. coli on water quality and public health is also discussed.
Neonatal infections caused by Escherichia coli at the National ...

African Journals Online (AJOL)

Background: Escherichia coli (E.coli) has been implicated as a common cause of both early and late onset neonatal infections. The emergence of different strains of E.coli that are multiply resistant to commonly used antibiotics has made continuous antibiotics surveillance relevant. Knowledge about common infections ...
neonatal infections caused by escherichia coli at the national

African Journals Online (AJOL)

boaz

Background: Escherichia coli (E.coli) has been implicated as a common cause of both early and late onset neonatal infections. The emergence of different strains of E.coli that are multiply resistant to commonly used antibiotics has made continuous antibiotics surveillance relevant. Knowledge about common infections ...
Molecular prophage typing of avian pathogenic Escherichia coli.

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Kwon, Hyuk-Joon; Seong, Won-Jin; Kim, Jae-Hong

2013-03-23

Escherichia coli prophages confer virulence and resistance to physico-chemical, nutritional, and antibiotic stresses on their hosts, and they enhance the evolution of E. coli. Thus, studies on profiles of E. coli prophages are valuable to understand the population structure and evolution of E. coli pathogenicity. Large terminase genes participate in phage genome packaging and are one of the cornerstones for the identification of prophages. Thus, we designed primers to detect 16 types of large terminase genes and analyzed the genomes of 48 E. coli and Shigella reference strains for the prophage markers. We also investigated the distribution of the 16 prophage markers among 92 avian pathogenic E. coli (APEC) strains. APEC strains were classified into 61 prophage types (PPTs). Each strain was different from the reference strains as measured by the PPTs and from the frequency of each prophage marker. Investigation of the distribution of prophage-related serum resistance (bor), toxin (stx1 and cdtI), and T3SS effector (lom, espK, sopE, nleB, and ospG) genes revealed the presence of bor (44.1%), lom (95.5%) and cdtI (9.1%) in APEC strains with related prophages. Therefore, the molecular prophage typing method may be useful to understand population structure and evolution of E. coli pathogenicity, and further studies on the mobility of the prophages and the roles of virulence genes in APEC pathogenicity may be valuable. Copyright © 2012 Elsevier B.V. All rights reserved.
The architecture of ArgR-DNA complexes at the genome-scale in Escherichia coli

DEFF Research Database (Denmark)

Cho, Suhyung; Cho, Yoo-Bok; Kang, Taek Jin

2015-01-01

DNA-binding motifs that are recognized by transcription factors (TFs) have been well studied; however, challenges remain in determining the in vivo architecture of TF-DNA complexes on a genome-scale. Here, we determined the in vivo architecture of Escherichia coli arginine repressor (ArgR)-DNA co...
Toxin production and antibiotic resistances in Escherichia coli isolated from bathing areas along the coastline of the Oslo fjord.

Science.gov (United States)

Charnock, Colin; Nordlie, Anne-Lise; Hjeltnes, Bjarne

2014-09-01

The presence of enterovirulent and/or antibiotic resistant strains of Escherichia coli in recreational bathing waters would represent a clear health issue. In total, 144 E. coli isolated from 26 beaches along the inner Oslo fjord were examined for virulence determinants and resistance to clinically important antibiotics. No isolates possessed the genetic determinants associated with enterotoxigenic strains and none showed the prototypic sorbitol negative, O157:H7 phenotype. A small number (∼1 %) produced alpha-hemolysin. Occurrences and patterns of antibiotic resistances were similar to those of E. coli isolated previously from environmental samples. In total, 6 % of the strains showed one or more clinically relevant resistances and 1.4 % were multi-drug resistant. Microarray analyses suggested that the resistance determinants were generally associated with mobile genetic elements. Resistant strains were not clonally related, and were, furthermore not concentrated at one or a few beach sites. This suggests that these strains are entering the waters at a low rate but in a widespread manner. The study demonstrates that resistant E. coli are present in coastal bathing waters where they can come into contact with bathers, and that the resistance determinants are potentially transferable. Some of the resistances registered in the study are to important antibiotics used in human medicine such as fluoroquinolones. The spread of antibiotic resistant genes, from the clinical setting to the environment, has clear implications with respect to the current management of bacterial infections and the long term value of antimicrobial therapy. The present study is the first of its kind in Norway.
Non-Escherichia coli versus Escherichia coli community-acquired urinary tract infections in children hospitalized in a tertiary center: relative frequency, risk factors, antimicrobial resistance and outcome.

Science.gov (United States)

Marcus, Nir; Ashkenazi, Shai; Yaari, Arnon; Samra, Zmira; Livni, Gilat

2005-07-01

Currently hospitalization for children with urinary tract infections (UTIs) is reserved for severe or complicated cases. Changes may have taken place in the characteristics and causative uropathogens of hospital-treated community-acquired UTI. To study children hospitalized in a tertiary center with community-acquired UTI, compare Escherichia coli and non-E. coli UTI, define predictors for non-E. coli UTI and elucidate the appropriate therapeutic approach. A prospective clinical and laboratory study from 2001 through 2002 in a tertiary pediatric medical center. Patients were divided by results of the urine culture into E. coli and non-E. coli UTI groups, which were compared. Of 175 episodes of culture-proved UTI, 70 (40%) were caused by non-E. coli pathogens. Non-E. coli UTI was more commonly found in children who were male (P = 0.005), who had underlying renal abnormalities (P = 0.0085) and who had received antibiotic therapy in the prior month (P = 0.0009). Non-E. coli uropathogens were often resistant to antibiotics usually recommended for initial therapy for UTI, including cephalosporins and aminoglycosides; 19% were initially treated with inappropriate empiric intravenous antibiotics (compared with 2% for E. coli UTI, P = 0.0001), with a longer hospitalization. Current treatment routines are often inappropriate for hospitalized children with non-E. coli UTI, which is relatively common in this population. The defined risk factors associated with non-E. coli UTIs and its antimicrobial resistance patterns should be considered to improve empiric antibiotic therapy for these infections.
Antimicrobial activity of traditional wines (Sopi and Moke against Salmonella sp. and Escherichia coli

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Annytha Ina Rohi Detha

2016-09-01

Full Text Available Objective: Sopi and Moke are two traditional wines in Indonesia. The present study aimed at investigating the antimicrobial effects of Sopi and Moke as compared to other commercial disinfectants. Materials and methods: The alcohol level and pH of the traditional wines (Sopi and Moke were determined by alcohol meter and pH meter, respectively. The susceptibility test was perfomed to determine the antimicrobial activity of Sopi against Escherichia coli which was isolated from cattle, and the activity of Moke was tested against Salmonella sp. which was a local isolate of poultry. Results: In susceptibility test, Sopi showed 17.5 mm in zone of inhibition against E. coli, while Formades and reg;, a commercial disinfectant showed 16 mm of zone of inhibition against the same bacteria. Moke showed 17.5 mm inhibition zone against Salmonella sp., whereas Antisep and reg;, a commercial disinfectant had 28 mm of inhibition zone against the same isolate. Conclusion: The results indicate that Sopi and Moke have antimicrobial effects on E. coli and Salmonella sp., respectively. The findings of this study suggest that Sopi and Moke can be used as potential antimicrobial agents. [J Adv Vet Anim Res 2016; 3(3.000: 282-285
Pulsed-Plasma Disinfection of Water Containing Escherichia coli

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Satoh, Kohki; MacGregor, Scott J.; Anderson, John G.; Woolsey, Gerry A.; Fouracre, R. Anthony

2007-03-01

The disinfection of water containing the microorganism, Escherichia coli (E. coli) by exposure to a pulsed-discharge plasma generated above the water using a multineedle electrode (plasma-exposure treatment), and by sparging the off-gas of the pulsed plasma into the water (off-gas-sparging treatment), is performed in the ambient gases of air, oxygen, and nitrogen. For the off-gas-sparging treatment, bactericidal action is observed only when oxygen is used as the ambient gas, and ozone is found to generate the bactericidal action. For the plasma-exposure treatment, the density of E. coli bacteria decreases exponentially with plasma-exposure time for all the ambient gases. It may be concluded that the main contributors to E. coli inactivation are particle species produced by the pulsed plasma. For the ambient gases of air and nitrogen, the influence of acidification of the water in the system, as a result of pulsed-plasma exposure, may also contribute to the decay of E. coli density.
Investigation of synthesis and release of poly-β-hydroxybutyrate in Escherichia coli

International Nuclear Information System (INIS)

Kainz, A. W.

2003-06-01

Polyhydroxybutyrate (PHB) is synthesized by bacteria as a storage compound for energy and carbon, if a carbon source is present in excess. Due to its material properties it can be used for substitutes of certain plastics. The advantage of PHB is the biodegradability. PHB is not only present in bacteria but also in other organisms such as plants and animals. The presence of PHB in humans has led to attempts during the last decade to use PHB as an implant material. This work deals with the production of PHB in recombinant bacteria and studies on the quality of the PHB synthesized. If PHB is used for medical applications like implants, it should be in the amorphous state. Therefore cell lysis has been the method of choice for yielding the PHB granules from bacteria. In this studies the bacteria were lysed by protein E from bacteriophage φX174. However, in contrast to earlier studies there was no release of PHB through lysis. Through atomic force microscopy it was possible to measure the diameter of the lysis hole which had a dimension of 30 to 80 nm. Using Fourier transformed infrared spectroscopy (FTIR) it was possible to determine the crystallinity of PHB. Because it was not possible to get PHB granules through cell lysis, the granules were extracted using a French press. However, this method revealed ratios of crystallinity of 75 % to 94 %. Also the contamination of PHB granules with protein and LPS was too high for use in medical applications. Thus using a French press as an alternative method to extract granules from E. coli cells is not suitable for medical applications of PHB as an implant material. Production of PHB in E. coli could be traced by FTIR. It was possible to determine the formation of PHB in recombinant E. coli. Also the consumption of glucose in the media could be determined. Single cells of E. coli (p4A) were investigated using confocal laser scanning microscopy and confocal Raman spectroscopy. It was observed that 74 % of cells begin PHB
Insights into the evolution of pathogenicity of Escherichia coli from genomic analysis of intestinal E. coli of Marmota himalayana in Qinghai-Tibet plateau of China.

Science.gov (United States)

Lu, Shan; Jin, Dong; Wu, Shusheng; Yang, Jing; Lan, Ruiting; Bai, Xiangning; Liu, Sha; Meng, Qiong; Yuan, Xuejiao; Zhou, Juan; Pu, Ji; Chen, Qiang; Dai, Hang; Hu, Yuanyuan; Xiong, Yanwen; Ye, Changyun; Xu, Jianguo

2016-12-07

Escherichia coli is both of a widespread harmless gut commensal and a versatile pathogen of humans. Domestic animals are a well-known reservoir for pathogenic E. coli. However, studies of E. coli populations from wild animals that have been separated from human activities had been very limited. Here we obtained 580 isolates from intestinal contents of 116 wild Marmot Marmota himalayana from Qinghai-Tibet plateau, China, with five isolates per animal. We selected 125 (hereinafter referred to as strains) from the 580 isolates for genome sequencing, based on unique pulse field gel electrophoresis patterns and at least one isolate per animal. Whole genome sequence analysis revealed that all 125 strains carried at least one and the majority (79.2%) carried multiple virulence genes based on the analysis of 22 selected virulence genes. In particular, the majority of the strains carried virulence genes from different pathovars as potential 'hybrid pathogens'. The alleles of eight virulence genes from the Marmot E. coli were found to have diverged earlier than all known alleles from human and other animal E. coli. Phylogenetic analysis of the 125 Marmot E. coli genomes and 355 genomes selected from 1622 human and other E. coli strains identified two new phylogroups, G and H, both of which diverged earlier than the other phylogroups. Eight of the 12 well-known pathogenic E. coli lineages were found to share a most recent common ancestor with one or more Marmot E. coli strains. Our results suggested that the intestinal E. coli of the Marmots contained a diverse virulence gene pool and is potentially pathogenic to humans. These findings provided a new understanding of the evolutionary origin of pathogenic E. coli.

Characterization of Multidrug Resistant Extended-Spectrum Beta-Lactamase-Producing Escherichia coli among Uropathogens of Pediatrics in North of Iran

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Mohammad Sadegh Rezai

2015-01-01

Full Text Available Escherichia coli remains as one of the most important bacteria causing infections in pediatrics and producing extended-spectrum beta-lactamases (ESBLs making them resistant to beta-lactam antibiotics. In this study we aimed to genotype ESBL-producing E. coli isolates from pediatric patients for ESBL genes and determine their association with antimicrobial resistance. One hundred of the E. coli isolates were initially considered ESBL producing based on their MIC results. These isolates were then tested by polymerase chain reaction (PCR for the presence or absence of CTX, TEM, SHV, GES, and VEB beta-lactamase genes. About 30.5% of isolated E. coli was ESBL-producing strain. The TEM gene was the most prevalent (49% followed by SHV (44%, CTX (28%, VEB (8%, and GES (0% genes. The ESBL-producing E. coli isolates were susceptible to carbapenems (66% and amikacin (58% and showed high resistance to cefixime (99%, colistin (82%, and ciprofloxacin (76%. In conclusion, carbapenems were the most effective antibiotics against ESBl-producing E. coli in urinary tract infection in North of Iran. The most prevalent gene is the TEM-type, but the other resistant genes and their antimicrobial resistance are on the rise.
Fate of naturally occurring Escherichia coli O157:H7 and other zoonotic pathogens during minimally managed bovine feedlot manure composting processes

Science.gov (United States)

Reducing Escherichia coli O157:H7 in livestock manures before application to cropland is critical for reducing the risk of foodborne illness associated with produce. Our objective was to determine the fate of naturally occurring E. coli O157:H7 and other pathogens during minimally managed on-farm bo...
Ischemic colitis or melanosis coli: a case report

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Nadeem Mohammed

2007-09-01

Full Text Available Abstract Background Melanosis Coli is described as black or brown discolouration of the mucosa of the colon. Its a benign condition, which arises from anthraquinone laxative abuse and has no symptoms of its own. The main importance of diagnosing Melanosis Coli correctly lies in the fact that if its extensive, there may be difficulty in differentiating it from ischemic colitis. Case presentation We present a case of extensive Melanosis Coli involving the whole of large bowel that appeared gangrenous. A sub total colectomy was performed on presumed diagnosis of ischemic bowel. Conclusion This report reminds the clinicians that extensive Melanosis Coli may mimic ischemic colitis and thus must be considered as a differential diagnosis.
Changing plasmid types responsible for extended spectrum cephalosporin resistance in Escherichia coli O157:H7 in the United States, 1996–2009

OpenAIRE

Folster, J. P.; Pecic, G.; Stroika, S.; Rickert, R.; Whichard, J.

2014-01-01

Escherichia coli O157 is a major cause of foodborne illness. Plasmids are genetic elements that mobilize antimicrobial resistance determinants including blaCMY β-lactamases that confer resistance to extended-spectrum cephalosporins (ESC). ESCs are important for treating a variety of infections. IncA/C plasmids are found among diverse sources, including cattle, the principal source of E. coli O157 infections in humans. IncI1 plasmids are common among E. coli and Salmonella from poultry and oth...
Escherichia Coli

Science.gov (United States)

Goodsell, David S.

2009-01-01

Diverse biological data may be used to create illustrations of molecules in their cellular context. I describe the scientific results that support a recent textbook illustration of an "Escherichia coli cell". The image magnifies a portion of the bacterium at one million times, showing the location and form of individual macromolecules. Results…
Fluoroquinolone-Resistant Escherichia coli Infections after Transrectal Biopsy of the Prostate in the Veterans Affairs Healthcare System

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Elie Antoun Saade

2016-09-01

Full Text Available Background: Recent reports suggest that infections due to fluoroquinolone-resistant Escherichia coli (E. coli are an increasingly common complication of transrectal biopsy of the prostate (TBP in the United States. A better understanding of the magnitude and scope of these infections is needed to guide prevention efforts. Our objective is to determine whether the incidence of infections due to fluoroquinolone-resistant E. coli after TBP has increased nationwide in the Veterans Affairs Health Care System and to identify risk factors for infection. Methods: We performed a retrospective, observational cohort study and a nested case-control study within the US Deparment of Veterans Affairs Healthcare System. The primary outcomes were the incidence of urinary tract infection (UTI and bacteremia with E. coli and with fluoroquinolone-resistant E. coli strains within 30 days after TBP. Secondary endpoints focused on the correlation between fluoroquinolone-resistance in all urinary E. coli isolates and post-TBP infection and risk factors for infection due to fluoroquinolone-resistant E. coli infection. Results: 245 618 patients undergoing 302 168 TBP procedures from 2000 through 2013 were included in the cohort study, and 59 469 patients undergoing TBP from 2011 through 2013 were included in the nested case-control study. Between 2000 and 2013, there was a 5-fold increase in the incidence of E. coli UTI (0.18%–0.93% and a 4-fold increase in the incidence of E. coli bacteremia (0.04%–0.18% after TBP that was attributable to an increase in the incidence of fluoroquinolone-resistant E. coli UTI (0.03%–0.75% and bacteremia (0.01%–0.14%. The increasing incidence of fluoroquinolone-resistant E. coli infections after TBP occurred in parallel with increasing rates of fluoroquinolone-resistance in all urinary E. coli isolates. By multivariable logistic regression analysis, independent risk factors for fluoroquinolone
Immobilizing live Escherichia coli for AFM studies of surface dynamics

International Nuclear Information System (INIS)

Lonergan, N.E.; Britt, L.D.; Sullivan, C.J.

2014-01-01

Atomic force microscopy (AFM) is a probe-based technique that permits high resolution imaging of live bacterial cells. However, stably immobilizing cells to withstand the probe-based lateral forces remains an obstacle in AFM mediated studies, especially those of live, rod shaped bacteria in nutrient media. Consequently, AFM has been under-utilized in the research of bacterial surface dynamics. The aim of the current study was to immobilize a less adherent Escherichia coli strain in a method that both facilitates AFM imaging in nutrient broth and preserves overall cell viability. Immobilization reagents and buffers were systematically evaluated and the cell membrane integrity was monitored in all sample preparations. As expected, the biocompatible gelatin coated surfaces facilitated stable cell attachment in lower ionic strength buffers, yet poorly immobilized cells in higher ionic strength buffers. In comparison, poly-L-lysine surfaces bound cells in both low and high ionic strength buffers. The benefit of the poly-L-lysine binding capacity was offset by the compromised membrane integrity exhibited by cells on poly-L-lysine surfaces. However, the addition of divalent cations and glucose to the immobilization buffer was found to mitigate this unfavorable effect. Ultimately, immobilization of E. coli cells on poly-L-lysine surfaces in a lower ionic strength buffer supplemented with Mg 2+ and Ca 2+ was determined to provide optimal cell attachment without compromising the overall cell viability. Cells immobilized in this method were stably imaged in media through multiple division cycles. Furthermore, permeability assays indicated that E. coli cells recover from the hypoosmotic stress caused by immobilization in low ionic strength buffers. Taken together, this data suggests that stable immobilization of viable cells on poly-L-lysine surfaces can be accomplished in lower ionic strength buffers that are supplemented with divalent cations for membrane stabilization while
Patch size and base composition of ultraviolet light-induced repair synthesis in toluenized Escherichia coli

Energy Technology Data Exchange (ETDEWEB)

Ben-Ishai, R; Sharon, R [Technion-Israel Inst. of Tech., Haifa

1978-04-15

Small patch repair in ultraviolet-irradiated Escherichia coli was saturated at deoxynucleoside triphosphate concentrations (approximately 2..mu..M of each dNTP) that are severly limiting for DNA replication. The low requirement of the repair process for dNTPs permitted direct demonstration of u.v.-induced DNA synthesis by incorporation of labelled dNTP and determination of its extent, base composition and patch size. It is concluded that DNA polymerase 1 is involved in small patch repair and that an average of 13 to 16 nucleotides are re-inserted per pyrimidine dimer excised. The average base composition of the repaired stretches adjacent to the dimers is similar to that of total E.coli DNA. An assay utilizing endogenous u.v.-specific endonuclease to determine dimer excision is described.
Escherichia coli survival in waters: Temperature dependence

Science.gov (United States)

Knowing the survival rates of water-borne Escherichia coli is important in evaluating microbial contamination and making appropriate management decisions. E. coli survival rates are dependent on temperature, a dependency that is routinely expressed using an analogue of the Q10 mo...
Genetical and functional investigation of fliC genes encoding flagellar serotype H4 in wildtype strains of Escherichia coli and in a laboratory E. coli K-12 strain expressing flagellar antigen type H48

Directory of Open Access Journals (Sweden)

Schaudinn Christoph

2005-01-01

Full Text Available Abstract Background Serotyping of O-(lipopolysaccharide and H-(flagellar antigens is a wideley used method for identification of pathogenic strains and clones of Escherichia coli. At present, 176 O- and 53 H-antigens are described for E. coli which occur in different combinations in the strains. The flagellar antigen H4 is widely present in E. coli strains of different O-serotypes and pathotypes and we have investigated the genetic relationship between H4 encoding fliC genes by PCR, nucleotide sequencing and expression studies. Results The complete nucleotide sequence of fliC genes present in E. coli reference strains U9-41 (O2:K1:H4 and P12b (O15:H17 was determined and both were found 99.3% (1043 of 1050 nucleotides identical in their coding sequence. A PCR/RFLP protocol was developed for typing of fliC-H4 strains and 88 E. coli strains reacting with H4 antiserum were investigated. Nucleotide sequencing of complete fliC genes of six E. coli strains which were selected based on serum agglutination titers, fliC-PCR genotyping and reference data revealed 96.6 to 100% identity on the amino acid level. The functional expression of flagellin encoded by fliC-H4 from strain U9-41 and from our strain P12b which is an H4 expressing variant type was investigated in the E. coli K-12 strain JM109 which encodes flagellar type H48. The fliC recombinant plasmid carrying JM109 strains reacted with both H4 and H48 specific antisera whereas JM109 reacted only with the H48 antiserum. By immunoelectron microscopy, we could show that the flagella made by the fliC-H4 recombinant plasmid carrying strain are constituted of H48 and H4 flagellins which are co-assembled into functional flagella. Conclusion The flagellar serotype H4 is encoded by closely related fliC genes present in serologically different types of E. coli strainswhich were isolated at different time periods and geographical locations. Our expression studies show for the first time, that flagellins of
Environmental Escherichia coli: ecology and public health implications-a review.

Science.gov (United States)

Jang, J; Hur, H-G; Sadowsky, M J; Byappanahalli, M N; Yan, T; Ishii, S

2017-09-01

Escherichia coli is classified as a rod-shaped, Gram-negative bacterium in the family Enterobacteriaceae. The bacterium mainly inhabits the lower intestinal tract of warm-blooded animals, including humans, and is often discharged into the environment through faeces or wastewater effluent. The presence of E. coli in environmental waters has long been considered as an indicator of recent faecal pollution. However, numerous recent studies have reported that some specific strains of E. coli can survive for long periods of time, and potentially reproduce, in extraintestinal environments. This indicates that E. coli can be integrated into indigenous microbial communities in the environment. This naturalization phenomenon calls into question the reliability of E. coli as a faecal indicator bacterium (FIB). Recently, many studies reported that E. coli populations in the environment are affected by ambient environmental conditions affecting their long-term survival. Large-scale studies of population genetics revealed the diversity and complexity of E. coli strains in various environments, which are affected by multiple environmental factors. This review examines the current knowledge on the ecology of E. coli strains in various environments with regard to its role as a FIB and as a naturalized member of indigenous microbial communities. Special emphasis is given on the growth of pathogenic E. coli in the environment, and the population genetics of environmental members of the genus Escherichia. The impact of environmental E. coli on water quality and public health is also discussed. © 2017 The Society for Applied Microbiology.
Low Temperature Plasma for decontamination of E. coli in milk.

Science.gov (United States)

Gurol, C; Ekinci, F Y; Aslan, N; Korachi, M

2012-06-15

Raw milk is a natural, highly nutritious product and a quick and easy supplement for human dietary requirements. Elimination of bacteria in milk has been a problem for decades and new methods with regards to non-thermal applications which do not harm the chemical composition of milk, are currently under investigation. The objective of the study was to determine the potential use of a novel, Low Temperature Plasma (LTP) system for its capability of killing Escherichia coli in milk with different fat contents. The time dependent effect of atmospheric corona discharge generated with 9kV of AC power supply on E. coli ATCC 25922 dispersed in whole, semi skimmed and skimmed milk was examined. Plasma was applied at time intervals of 0, 3, 6, 9, 12, 15 and 20min. A significant 54% reduction in the population of E. coli cells after only 3min was observed regardless of the fat content of the milk. The initial pre-plasma bacterial count of 7.78 Log CFU/ml in whole milk was decreased to 3.63 Log CFU/ml after 20min of plasma application. LTP did not cause any significant change to the pH and color values of raw milk samples. No viable cells were detected after one week examination in whole milk samples and remained so over the 6week storage period. The findings of this study show that the novel LTP system tested was able to significantly reduce E. coli in milk by more than a 3 fold log reduction without significantly affecting pH or color properties. Copyright © 2012 Elsevier B.V. All rights reserved.
Fecal colonization with P-fimbriated Escherichia coli in newborn children and relation to development of extraintestinal E. coli infections.

Science.gov (United States)

Tullus, K

1987-01-01

The incidence of E. coli pyelonephritis before the age of one year among the children born at Danderyd Hospital during a ten year period was studied. During the study period, 4 or 5 outbreaks of E. coli pyelonephritis occurred among the children who had previously been staying in the hospital's neonatal ward. These outbreaks seemed to have been caused by nosocomial spread of and fecal colonization with certain virulent E. coli strains among the children staying in the ward during certain periods of time. The strains that were spread in the ward seemed to belong to certain pyelonephritogenic E. coli clones of the serotypes O6:K5, O4:K3 and possibly O6:K2. Although the children became fecally colonized with the strains in the neonatal ward, most fell ill some time after they had left the ward. The mean age at the development of their first pyelonephritis was 3.4 months for the boys and 6.2 months for the girls, who had been cared for in this ward. A correlation between the number of infections and the bed occupancy of the ward could be found (p less than 0.01). The risk for a child staying in the ward during an outbreak to develop pyelonephritis was about 5-10%. There was a baseline incidence rate of 0.6-0.7% during non-epidemic periods. During one of the outbreaks there was also an increased incidence rate of E. coli septicemia among the children staying in the neonatal ward. The predictive value of fecal colonization with P-fimbriated E. coli for the later development of extraintestinal E. coli infections was studied in a 2.5 year prospective study. During this study period there was a baseline incidence rate of 10-20% fecal colonization with P-fimbriated E. coli among the children staying in both the neonatal and maternity wards, interrupted only by minor peaks of colonization with such strains. Length of stay in the neonatal ward and a high bed occupancy of the neonatal ward were statistically correlated to fecal colonization with P-fimbriated E. coli strains (p
Low resolution solution structure of the Apo form of Escherichia coli haemoglobin protease Hbp.

NARCIS (Netherlands)

scott, D.J.; Grossman, J.G.; Tame, J.R.H.; Byron, O.; Wilson, K.S.; Otto, B.R.

2002-01-01

We have studied the solution properties of the apo form of the haemoglobin protease or "haemoglobinase", Hbp, a principal component of an important iron acquisition system in pathogenic Escherichia coli. Experimental determination of secondary structure content from circular dichroism (CD)
Ontology-based literature mining of E. coli vaccine-associated gene interaction networks.

Science.gov (United States)

Hur, Junguk; Özgür, Arzucan; He, Yongqun

2017-03-14

Pathogenic Escherichia coli infections cause various diseases in humans and many animal species. However, with extensive E. coli vaccine research, we are still unable to fully protect ourselves against E. coli infections. To more rational development of effective and safe E. coli vaccine, it is important to better understand E. coli vaccine-associated gene interaction networks. In this study, we first extended the Vaccine Ontology (VO) to semantically represent various E. coli vaccines and genes used in the vaccine development. We also normalized E. coli gene names compiled from the annotations of various E. coli strains using a pan-genome-based annotation strategy. The Interaction Network Ontology (INO) includes a hierarchy of various interaction-related keywords useful for literature mining. Using VO, INO, and normalized E. coli gene names, we applied an ontology-based SciMiner literature mining strategy to mine all PubMed abstracts and retrieve E. coli vaccine-associated E. coli gene interactions. Four centrality metrics (i.e., degree, eigenvector, closeness, and betweenness) were calculated for identifying highly ranked genes and interaction types. Using vaccine-related PubMed abstracts, our study identified 11,350 sentences that contain 88 unique INO interactions types and 1,781 unique E. coli genes. Each sentence contained at least one interaction type and two unique E. coli genes. An E. coli gene interaction network of genes and INO interaction types was created. From this big network, a sub-network consisting of 5 E. coli vaccine genes, including carA, carB, fimH, fepA, and vat, and 62 other E. coli genes, and 25 INO interaction types was identified. While many interaction types represent direct interactions between two indicated genes, our study has also shown that many of these retrieved interaction types are indirect in that the two genes participated in the specified interaction process in a required but indirect process. Our centrality analysis of
Melanosis coli in patients with colon cancer

Directory of Open Access Journals (Sweden)

Dorota Biernacka-Wawrzonek

2016-12-01

Full Text Available Intoduction: Melanosis coli is a benign lesion affecting the mucosa of the large intestine. There is a relationship between the presence of melanosis and anthraquinone laxative use. Melanosis coli is also observed in patients with colon cancer, but there is doubt whether these two conditions are related. Aim : To analyze the correlation between melanosis and colon cancer. Material and methods: We analyzed retrospectively 436 patients undergoing colon cancer surgery. There were 246 women and 190 men. Patients were divided into three age groups: under 50 years, between 51 and 65 years, and over 66 years. We analyzed sections of the cancer and intestinal mucosa from the tumor’s proximal (2–5 cm and distal (8–10 cm zone. Results : Melanosis coli was present in 52 patients, which represents 11.9% of patients with colon cancer. More often it was present in women. The most common location of melanosis and colon cancer was the terminal part of the large intestine. In patients below 50 years of age in both sexes melanosis coli did not occur. In men, melanosis was more common in the age group over 66 years. Intensity of pigmentation was higher in the tumor’s distal zone. Conclusions : The incidence of melanosis coli increases with age, similar to that of colon cancer. Melanosis was not present inside tumors, in almost half of the cases it was not present in the proximal zone, and the degree of pigmentation increased in distal zone. The cause-effect relationship between melanosis coli and colon cancer remains uncertain.
Characterization of genetic determinants of extended-spectrum cephalosporinases (ESCs) in Escherichia coli isolates from Danish and imported poultry meat

DEFF Research Database (Denmark)

Bergenholz, Rikke; Jørgensen, Mikael Skaanning; Hansen, Lars H.

2009-01-01

Sir, The predominant cause of resistance towards cephalosporins in Escherichia coli is production of plasmid-encoded extended-spectrum ß-lactamases (ESBLs) and AmpC-type ß-lactamases, also referred to as extended-spectrum cephalosporinases (ESCs). Most studies have focused on description of ESCs...
Survival of Escherichia coli O157:H7 in needle-tenderized dry cured Westphalian ham.

Science.gov (United States)

Graumann, Gary H; Holley, Richard A

2007-09-15

Westphalian ham is a dry cured, ready-to-eat product that is manufactured without a lethal heat treatment. Hams are preserved by a process that involves curing, fermenting, smoking and drying, which may take 3 months or more to complete. The process can be accelerated by tenderizing the meat with solid needles, to increase the rate of cure-salt diffusion throughout muscle tissues. In this study, intact hams were immersed in a solution containing a five strain cocktail of Escherichia coli O157:H7 at 8 log cfu/mL, to determine whether needle treatment before cure application would internalize organisms from the surface. In two trials, the survival of E. coli O157:H7 on external surfaces and within deep tissues after needle treatment was followed during the ripening of hams. The injured E. coli O157:H7 cells were recovered by plating samples on pre-poured Tryptic Soy Agar plates which were incubated for 3 to 4 h at 35 degrees C, overlaid with Sorbitol MacConkey Agar containing cefixime and tellurite and re-incubated at 35 degrees C for 48 to 72 h. Inoculated-injected hams initially carried E. coli O157:H7 at numbers of 7.3 and 4.6 log cfu/g E. coli O157:H7 on the surface and inside, respectively. After 112 d of ripening, which included 79 d of drying, no E. coli O157:H7 were detected at the surface of hams following enrichment, whereas in deep tissue the organism was recovered at numbers of 3.1 log cfu/g. The Westphalian ham ripening procedure evidently was not adequate to eliminate E. coli O157:H7 internalized by needle tenderization.
Potensi Antibakteri Ekstrak Bunga Soka (Ixora coccinea L terhadap Staphylococcus aureus dan Escherichia coli

Directory of Open Access Journals (Sweden)

Munira Munira

2016-11-01

Full Text Available Soka plants (Ixora coccineal L. often used to treat diarrhea, dysentery and wounds. This study was conducted to determine the effect of soka flower ethanol extract in inhibiting the growth of Staphylococcus aureus and Escherichia coli. This study is experimentally using completely randomized design (CRD with 4 treatments and 6 repetitions which is distilled water as a control, the ethanol extract of soka flowers concentration are 100%, 75%, and 50%. Microbiological test using the diffusion method of Kirby-Baueur. Phytochemical test results soka ethanol extracts of flowers contain alkaloids, flavonoids, tannins, saponins, and triterpenoid. ANOVA test results ethanol extracts of soka flowers greatly affect the growth of S. aureus and E. coli (P=0.000. Duncan test results an average diameter of inhibition zone for the ethanol extract of soka flowers against S. aureus at a concentration of 100% (14.50 mm was significantly different from the concentration of 75% (10.33 mm and concentration of 50% (10.67 mm, while the average diameter of inhibition zone for the ethanol extract of soka flowers against E. coli at 100% (11.00 mm was not significantly different from the 75% (7.83 mm and 50% (7.50 mm. The ability of ethanol extract of soka flower in inhibition zone against S. aureus greater than E. coli. Keywords: Ixora coccinea L., inhibition zone, Staphylococcus aureus and Escherichia coli.
No evidence for a bovine mastitis Escherichia coli pathotype.

Science.gov (United States)

Leimbach, Andreas; Poehlein, Anja; Vollmers, John; Görlich, Dennis; Daniel, Rolf; Dobrindt, Ulrich

2017-05-08

Escherichia coli bovine mastitis is a disease of significant economic importance in the dairy industry. Molecular characterization of mastitis-associated E. coli (MAEC) did not result in the identification of common traits. Nevertheless, a mammary pathogenic E. coli (MPEC) pathotype has been proposed suggesting virulence traits that differentiate MAEC from commensal E. coli. The present study was designed to investigate the MPEC pathotype hypothesis by comparing the genomes of MAEC and commensal bovine E. coli. We sequenced the genomes of eight E. coli isolated from bovine mastitis cases and six fecal commensal isolates from udder-healthy cows. We analyzed the phylogenetic history of bovine E. coli genomes by supplementing this strain panel with eleven bovine-associated E. coli from public databases. The majority of the isolates originate from phylogroups A and B1, but neither MAEC nor commensal strains could be unambiguously distinguished by phylogenetic lineage. The gene content of both MAEC and commensal strains is highly diverse and dominated by their phylogenetic background. Although individual strains carry some typical E. coli virulence-associated genes, no traits important for pathogenicity could be specifically attributed to MAEC. Instead, both commensal strains and MAEC have very few gene families enriched in either pathotype. Only the aerobactin siderophore gene cluster was enriched in commensal E. coli within our strain panel. This is the first characterization of a phylogenetically diverse strain panel including several MAEC and commensal isolates. With our comparative genomics approach we could not confirm previous studies that argue for a positive selection of specific traits enabling MAEC to elicit bovine mastitis. Instead, MAEC are facultative and opportunistic pathogens recruited from the highly diverse bovine gastrointestinal microbiota. Virulence-associated genes implicated in mastitis are a by-product of commensalism with the primary function

Sunlight inactivation of Escherichia coli in waste stabilization microcosms in a sahelian region (Ouagadougou, Burkina Faso).

Science.gov (United States)

Maïga, Ynoussa; Denyigba, Kokou; Wethe, Joseph; Ouattara, Aboubakar Sidiki

2009-02-09

Experiments on sunlight inactivation of Escherichia coli were conducted from November 2006 to June 2007 in eight outdoors microcosms with different depths filled with maturation pond wastewater in order to determine pond depth influence on sunlight inactivation of E. coli. The long-term aim was to maximize sunlight inactivation of waterborne pathogens in waste stabilization ponds (WSPs) in sahelian regions where number of sunny days enable longer exposure of wastewater to sunlight. The inactivation was followed during daylight from 8.00 h to 17.00 h and during the night. Sunlight inactivation rates (K(S)), as a function of cumulative global solar radiation (insolation), were 16 and 24 times higher than the corresponding dark inactivation (K(D)) rates, respectively in cold and warm season. In warm season, E. coli was inactivated far more rapidly. Inactivation of E. coli follows the evolution of radiation during the day. In shallow depth microcosms, E. coli was inactivated far more rapidly than in high depth microcosms. The physical chemical parameters [pH, dissolved oxygen (DO)] of microcosms water were higher in shallow depth microcosms than in high depth microcosms suggesting a synergistic effect of sunlight and these parameters to damage E. coli. To increase the efficiency of the elimination of waterborne bacteria, the use of maturation ponds with intermediate depths (0.4m) would be advisable in view of the high temperatures and thus evaporation recorded in sahelian regions.
ANALISIS KANDUNGAN BORAKS DAN Escherichia coli PADA JAJANAN BAKSO SAPI YANG DIPERDAGANGKAN DI KOTA BANJARBARU

Directory of Open Access Journals (Sweden)

Nur Rahmi

2016-09-01

Full Text Available This study aims to determine how the content of borax and Escherichia coli on meatballs snacks and the factors that affect the food security of meatballs snacks by using Easy Method of Borax Test and Method of Most Probable Number (MPN for Escherichia coli bacteria contamination. This research was conducted in Banjarbaru on 5 villages, and sampling technique used is stratified sampling. The results of the study showed that from 32 samples taken from five village location, it was not identified any borax based on PERMENKES No. 033 of 2012, while for the examination of Escherichia coli, there are 14 samples of meatballs (43.75% which were eligible, and 18 samples of meatballs (56.25% which containEscherichia coli ranges from 3.6 to 62 CFU /g or not meeting the criteria of ISO 7388: 2009. The factor that might not trigger the addition of borax is that the traders have a good knowledge and attitude toward borax which regarded as a toxic substance and can be harmful to health. Factors that cause microbial contamination of Escherichia coli on meatballs snacks is the lack of food hygiene and sanitation in the food processing, cooked food storage, transport, serving, sanitation facilities, and personnel handlers compared with the good supply of foodstuffs and food ingredients storage.
The role of Cra in regulating acetate excretion and osmotic tolerance in E. coli K-12 and E. coli B at high density growth.

Science.gov (United States)

Son, Young-Jin; Phue, Je-Nie; Trinh, Loc B; Lee, Sang Jun; Shiloach, Joseph

2011-06-30

E. coli B (BL21), unlike E.coli K-12 (JM109) is insensitive to glucose concentration and, therefore, grows faster and produces less acetate than E. coli K-12, especially when growing to high cell densities at high glucose concentration. By performing genomic analysis, it was demonstrated that the cause of this difference in sensitivity to the glucose concentration is the result of the differences in the central carbon metabolism activity. We hypothesized that the global transcription regulator Cra (FruR) is constitutively expressed in E. coli B and may be responsible for the different behaviour of the two strains. To investigate this possibility and better understand the function of Cra in the two strains, cra - negative E. coli B (BL21) and E. coli K-12 (JM109) were prepared and their growth behaviour and gene expression at high glucose were evaluated using microarray and real-time PCR. The deletion of the cra gene in E. coli B (BL21) minimally affected the growth and maximal acetate accumulation, while the deletion of the same gene in E.coli K-12 (JM109) caused the cells to stop growing as soon as acetate concentration reached 6.6 g/L and the media conductivity reached 21 mS/cm. ppsA (gluconeogenesis gene), aceBA (the glyoxylate shunt genes) and poxB (the acetate producing gene) were down-regulated in both strains, while acs (acetate uptake gene) was down-regulated only in E.coli B (BL21). These transcriptional differences had little effect on acetate and pyruvate production. Additionally, it was found that the lower growth of E. coli K-12 (JM109) strain was the result of transcription inhibition of the osmoprotectant producing bet operon (betABT). The transcriptional changes caused by the deletion of cra gene did not affect the activity of the central carbon metabolism, suggesting that Cra does not act alone; rather it interacts with other pleiotropic regulators to create a network of metabolic effects. An unexpected outcome of this work is the finding that cra
The organization of the fuc regulon specifying L-fucose dissimilation in Escherichia coli K12 as determined by gene cloning.

Science.gov (United States)

Chen, Y M; Zhu, Y; Lin, E C

1987-12-01

In Escherichia coli the six known genes specifying the utilization of L-fucose as carbon and energy source cluster at 60.2 min and constitute a regulon. These genes include fucP (encoding L-fucose permease), fucI (encoding L-fucose isomerase), fucK (encoding L-fuculose kinase), fucA (encoding L-fuculose 1-phosphate aldolase), fucO (encoding L-1,2-propanediol oxidoreductase), and fucR (encoding the regulatory protein). In this study the fuc genes were cloned and their positions on the chromosome were established by restriction endonuclease and complementation analyses. Clockwise, the gene order is: fucO-fucA-fucP-fucI-fucK-fucR. The operons comprising the structural genes and the direction of transcription were determined by complementation analysis and Southern blot hybridization. The fucPIK and fucA operons are transcribed clockwise. The fucO operon is transcribed counterclockwise. The fucR gene product activates the three structural operons in trans.
Comparison of 61 Sequenced Escherichia coli Genomes

DEFF Research Database (Denmark)

Lukjancenko, Oksana; Wassenaar, T. M.; Ussery, David

2010-01-01

Escherichia coli is an important component of the biosphere and is an ideal model for studies of processes involved in bacterial genome evolution. Sixty-one publically available E. coli and Shigella spp. sequenced genomes are compared, using basic methods to produce phylogenetic and proteomics...
lactamase in clinical isolates of Escherichia coli

African Journals Online (AJOL)

Jane

2011-08-22

Aug 22, 2011 ... The beta lactamase enzyme producing E. coli, resistant to β-lactam antibiotics, created many problems ... Key words: Escherichia coli, β-lactamase enzymes, TEM-type extended spectrum ... difficulties in treatment using antibiotics that are currently ... and chloramphenicol (30 µg) (Mast Diagnostics Ltd., UK).
Can Escherichia coli fly? The role of flies as transmitters of E. coli to food in an urban slum in Bangladesh.

Science.gov (United States)

Lindeberg, Yrja Lisa; Egedal, Karen; Hossain, Zenat Zebin; Phelps, Matthew; Tulsiani, Suhella; Farhana, Israt; Begum, Anowara; Jensen, Peter Kjaer Mackie

2018-01-01

To investigate the transmission of faecal bacteria by flies to food under natural settings. Over a period of 2 months, paired (exposed and non-exposed) containers with cooked rice were placed on the ground in kitchen areas in an urban slum area in Dhaka, Bangladesh, and the numbers of flies landing on the exposed rice were counted. Following exposure, the surface of the rice was microbiologically and molecularly analysed for the presence of Escherichia coli and genes of diarrhoeagenic E. coli and Shigella strains. Rice was at greater risk (P E. coli if flies landed on the rice than if no flies landed on the rice (odds ratio 5·4 (P 0·6 × 103 CFU. Genes of diarrhoeagenic E. coli and Shigella species were detected in 39 of 60 (65%) of exposed rice samples. Two fly species were identified: the common housefly (Musca domestica) and the oriental latrine fly (Chrysomya megacephala). Flies may transmit large quantities of E. coli to food under field settings. The findings highlight the importance of implementing control measures to minimise exposure of food to flies to ensure food safety. Fly control measures should be considered for the prevention of diarrhoeal diseases caused by E. coli. © 2017 John Wiley & Sons Ltd.
Photoreactivating enzyme from Escherichia coli

International Nuclear Information System (INIS)

Snapka, R.M.; Fuselier, C.O.

1977-01-01

Escherichia coli photoreactivating enzyme (PRE) has been purified in large amounts from an E.coli strain lysogenic for a defective lambda bacteriophage carrying the phr gene. The resulting enzyme had a pH optimum of 7.2 and an ionic strength optimum of 0.18. It consisted of an apoprotein and cofactor, both of which were necessary for catalytic activity. The apoprotein had a monomer molecular weight of 35,200 and showed stable aggregates under denaturing conditions. The amino acid analysis of the E.coli enzyme was very similar to that of the photoreactivating enzyme from orchid seedlings (Cattelya aurantiaca). Both had arginine at the amino terminus. The cofactor, like the holoenzyme, showed absorption, magnetic circular dichroism, and emission properties indicative of an adenine moiety. Although the isolated enzyme had an action spectrum which peaked at about 360 nm, neither the cofactor, apoenzyme nor holoenzyme showed any detectable absorption between 300 and 400 nm. (author)
Photoreactivating enzyme from Escherichia coli

Energy Technology Data Exchange (ETDEWEB)

Snapka, R M; Fuselier, C O [California Univ., Irvine (USA)

1977-05-01

Escherichia coli photoreactivating enzyme (PRE) has been purified in large amounts from an E.coli strain lysogenic for a defective lambda bacteriophage carrying the phr gene. The resulting enzyme had a pH optimum of 7.2 and an ionic strength optimum of 0.18. It consisted of an apoprotein and cofactor, both of which were necessary for catalytic activity. The apoprotein had a monomer molecular weight of 35,200 and showed stable aggregates under denaturing conditions. The amino acid analysis of the E.coli enzyme was very similar to that of the photoreactivating enzyme from orchid seedlings (Cattelya aurantiaca). Both had arginine at the amino terminus. The cofactor, like the holoenzyme, showed absorption, magnetic circular dichroism, and emission properties indicative of an adenine moiety. Although the isolated enzyme had an action spectrum which peaked at about 360 nm, neither the cofactor, apoenzyme nor holoenzyme showed any detectable absorption between 300 and 400 nm.
Crystal structure and mechanism of the lytic transglycosylase MltA from Escherichia coli

NARCIS (Netherlands)

van Straaten, Karin

2006-01-01

This thesis describes the determination and analysis of the 3D-structure of the lytic transglycosylase MltA from Escherichia coli by X-ray crystallography. This work aims to further increase our knowledge of the molecular details of the cleaving mechanism and the typical 1,6- anhydromuropeptide
Escherichia coli Concentrations in the Mill Creek Watershed, Cleveland, Ohio, 2001-2004

Science.gov (United States)

Brady, Amie M.G.

2007-01-01

Mill Creek in Cleveland, Ohio, receives discharges from combined-sewer overflows (CSOs) and other sanitary-sewage inputs. These discharges affect the water quality of the creek and that of its receiving stream, the Cuyahoga River. In an effort to mitigate this problem, the Northeast Ohio Regional Sewer District implemented a project to eliminate or control (by reducing the number of overflows) all of the CSOs in the Mill Creek watershed. This study focused on monitoring the microbiological water quality of the creek before and during sewage-collection system modifications. Routine samples were collected semimonthly from August 2001 through September 2004 at a site near a U.S. Geological Survey stream gage near the mouth of Mill Creek. In addition, event samples were collected September 19 and 22, 2003, when rainfall accumulations were 0.5 inches (in.) or greater. Concentrations of Escherichia coli (E. coli) were determined and instantaneous discharges were calculated. Streamflow and water-quality characteristics were measured at the time of sampling, and precipitation data measured at a nearby precipitation gage were obtained from the National Oceanic and Atmospheric Administration. Concentrations of E. coli were greater than Ohio's single-sample maximum for primary-contact recreation (298 colony-forming units per 100 milliliters (CFU/100 mL)) in 84 percent of the routine samples collected. In all but one routine sample E. coli concentrations in samples collected when instantaneous streamflows were greater than 20 cubic feet per second (ft3/s) were greater than Ohio's single-sample maximum. When precipitation occurred in the 24-hour period before routine sample collection, concentrations were greater than the maximum in 89 percent of the samples as compared to 73 percent when rainfall was absent during the 24 hours prior to routine sample collection. Before modifications to the sewage-collection system in the watershed began, E. coli concentrations in Mill Creek
Determining thermal inactivation of Escherichia coli O157:H7 in fresh compost by simulating early phases of the composting process.

Science.gov (United States)

Singh, Randhir; Kim, Jinkyung; Shepherd, Marion W; Luo, Feng; Jiang, Xiuping

2011-06-01

A three-strain mixture of Escherichia coli O157:H7 was inoculated into fresh dairy compost (ca. 10(7) CFU/g) with 40 or 50% moisture and was placed in an environmental chamber (ca. 70% humidity) that was programmed to ramp from room temperature to selected composting temperatures in 2 and 5 days to simulate the early composting phase. The surviving E. coli O157:H7 population was analyzed by direct plating and enrichment. Optimal and suboptimal compost mixes, with carbon/nitrogen (C/N) ratios of 25:1 and 16:1, respectively, were compared in this study. In the optimal compost mix, E. coli O157:H7 survived for 72, 48, and 24 h in compost with 40% moisture and for 72, 24, and 24 h with 50% moisture at 50, 55, and 60°C, respectively, following 2 days of come-up time (rate of heating up). However, in the suboptimal compost mix, the pathogen survived for 288, 72, and 48 h in compost with 40% moisture and for 240, 72, 24 h in compost with 50% moisture at the same temperatures, respectively. Pathogen survival was longer, with 5 days of come-up time compared with 2 days of come-up. Overall, E. coli O157:H7 was inactivated faster in the compost with 50% moisture than in the compost with 40% at 55 and 60°C. Both moisture and come-up time were significant factors affecting Weibull model parameters. Our results suggest that slow come-up time at the beginning of composting can extend pathogen survival during composting. Additionally, both the C/N ratio and the initial moisture level in the compost mix affect the rate of pathogen inactivation as well.
Investigation of carbon storage regulation network (csr genes) and phenotypic differences between acid sensitive and resistant Escherichia coli O157:H7 strains

Science.gov (United States)

Background: Escherichia coli O157:H7 and related serotype strains have previously been shown to vary in acid resistance, however, little is known about strain specific mechanisms of acid resistance. We examined sensitive and resistant E. coli strains to determine the effects of growth in minimal and...
Role of DNA polymerase I in liquid holding recovery of uv-irradiated Escherichia coli

Energy Technology Data Exchange (ETDEWEB)

Tang, M S; Patrick, M H [Texas Univ., Dallas (USA)

1977-09-01

Excision of cyclobutyl dipyrimidines from, and accumulation of strand interruptions in DNA of different strains of E.coli K12 were determined during liquid holding recovery after uv irradiation. The extent of Pyr <> Pyr excision was the same (20 to 25%) for both a polA mutant (E.coli P3478) and its parental wild type strain (E.coli W3110); however, single strand interruptions accumulated during liquid holding of polA cells, but not in the parental strain. In contrast, excision was greatly reduced in a mutant (KMBL 1789) which is defective in the 5' ..-->.. 3' exonucleolytic function of DNA polymerase I. These data suggest that excision and resynthesis during liquid holding are carried out primarily, if not entirely, by DNA polymerase I. It is further concluded that excision alone is both a necessary and sufficient condition to elicit liquid holding recovery, and that this excision requires a functional polymerase I 5' ..-->.. 3' exonuclease.
High temperature in combination with UV irradiation enhances horizontal transfer of stx2 gene from E. coli O157:H7 to non-pathogenic E. coli.

Directory of Open Access Journals (Sweden)

Wan-Fu Yue

Full Text Available Shiga toxin (stx genes have been transferred to numerous bacteria, one of which is E. coli O157:H7. It is a common belief that stx gene is transferred by bacteriophages, because stx genes are located on lambdoid prophages in the E. coli O157:H7 genome. Both E. coli O157:H7 and non-pathogenic E. coli are highly enriched in cattle feedlots. We hypothesized that strong UV radiation in combination with high temperature accelerates stx gene transfer into non-pathogenic E. coli in feedlots.E. coli O157:H7 EDL933 strain were subjected to different UV irradiation (0 or 0.5 kJ/m(2 combination with different temperature (22, 28, 30, 32, and 37 °C treatments, and the activation of lambdoid prophages was analyzed by plaque forming unit while induction of Stx2 prophages was quantified by quantitative real-time PCR. Data showed that lambdoid prophages in E. coli O157:H7, including phages carrying stx2, were activated under UV radiation, a process enhanced by elevated temperature. Consistently, western blotting analysis indicated that the production of Shiga toxin 2 was also dramatically increased by UV irradiation and high temperature. In situ colony hybridization screening indicated that these activated Stx2 prophages were capable of converting laboratory strain of E. coli K12 into new Shiga toxigenic E. coli, which were further confirmed by PCR and ELISA analysis.These data implicate that high environmental temperature in combination with UV irradiation accelerates the spread of stx genes through enhancing Stx prophage induction and Stx phage mediated gene transfer. Cattle feedlot sludge are teemed with E. coli O157:H7 and non-pathogenic E. coli, and is frequently exposed to UV radiation via sunlight, which may contribute to the rapid spread of stx gene to non-pathogenic E. coli and diversity of shiga toxin producing E. coli.
Lethality prediction for Escherichia coli 0157:H7 and Uropathogenic E. coli in ground chicken treated with high pressure processing and trans-cinnamaldehyde

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Pathogenic Escherichia coli, intestinal (O157:H7) as well as extraintestinal types (Uropathogenic E. coli (UPEC)) are commonly found in many foods including chicken meat. In this study we compared the resistance of E. coli O157:H7 to UPEC in chicken meat under the stresses of high hydrostatic pressu...
Synergistic effect of eugenol with Colistin against clinical isolated Colistin-resistant Escherichia coli strains

Directory of Open Access Journals (Sweden)

Yi-ming Wang

2018-01-01

Full Text Available Abstract Background Bacterial infections have become more challenging to treat due to the emergence of multidrug-resistant pathogenic bacteria. Combined antibiotics prove to be a relatively effective method to control such resistant strains. This study aim to investigate synergistic activity of eugenol combined with colistin against a collection of clinical isolated Escherichia coli (E.coli strains, and to evaluate potential interaction. Methods Antimicrobial susceptibility, minimum inhibitory concentration (MIC and fractional inhibitory concentration index (FICI of the bacteria were determined by disk diffusion assay, broth microdilution method and checkerboard assay, respectively. The mcr-1 mRNA expression was measured by Real-time PCR. To predict possible interactions between eugenol and MCR-1, molecular docking assay was taken. Results For total fourteen strains including eight colistin-resistant strains, eugenol was determined with MIC values of 4 to 8 μg/mL. Checkerboard dilution test suggested that eugenol exhibited synergistic activity when combined with colistin (FICI ranging from 0.375 to 0.625. Comparison analysis of Real-time PCR showed that synergy could significantly down-regulate expression of mcr-1 gene. A metal ion coordination bond with catalytic zinc atom and a hydrogen bond with crucial amino acid residue Ser284 of MCR-1 were observed after molecular docking, indicating antibacterial activity and direct molecular interactions of eugenol with MCR-1 protein. Conclusions Our results demonstrated that eugenol exhibited synergistic effect with colistin and enhanced its antimicrobial activity. This might further contribute to the antibacterial actions against colistin-resistant E.coli strains. Graphical abstract Synergistic effect of eugenol with colistin against colistin-resistant Escherichia coli isolates.
Analysis of whole genome sequencing for the Escherichia coli O157:H7 typing phages.

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Cowley, Lauren A; Beckett, Stephen J; Chase-Topping, Margo; Perry, Neil; Dallman, Tim J; Gally, David L; Jenkins, Claire

2015-04-08

Shiga toxin producing Escherichia coli O157 can cause severe bloody diarrhea and haemolytic uraemic syndrome. Phage typing of E. coli O157 facilitates public health surveillance and outbreak investigations, certain phage types are more likely to occupy specific niches and are associated with specific age groups and disease severity. The aim of this study was to analyse the genome sequences of 16 (fourteen T4 and two T7) E. coli O157 typing phages and to determine the genes responsible for the subtle differences in phage type profiles. The typing phages were sequenced using paired-end Illumina sequencing at The Genome Analysis Centre and the Animal Health and Veterinary Laboratories Agency and bioinformatics programs including Velvet, Brig and Easyfig were used to analyse them. A two-way Euclidian cluster analysis highlighted the associations between groups of phage types and typing phages. The analysis showed that the T7 typing phages (9 and 10) differed by only three genes and that the T4 typing phages formed three distinct groups of similar genomic sequences: Group 1 (1, 8, 11, 12 and 15, 16), Group 2 (3, 6, 7 and 13) and Group 3 (2, 4, 5 and 14). The E. coli O157 phage typing scheme exhibited a significantly modular network linked to the genetic similarity of each group showing that these groups are specialised to infect a subset of phage types. Sequencing the typing phage has enabled us to identify the variable genes within each group and to determine how this corresponds to changes in phage type.
Multidrug-Resistant and Extended Spectrum Beta-Lactamase-Producing Escherichia coli in Dutch Surface Water and Wastewater.

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Hetty Blaak

Full Text Available The goal of the current study was to gain insight into the prevalence and concentrations of antimicrobial resistant (AMR Escherichia coli in Dutch surface water, and to explore the role of wastewater as AMR contamination source.The prevalence of AMR E. coli was determined in 113 surface water samples obtained from 30 different water bodies, and in 33 wastewater samples obtained at five health care institutions (HCIs, seven municipal wastewater treatment plants (mWWTPs, and an airport WWTP. Overall, 846 surface water and 313 wastewater E. coli isolates were analysed with respect to susceptibility to eight antimicrobials (representing seven different classes: ampicillin, cefotaxime, tetracycline, ciprofloxacin, streptomycin, sulfamethoxazole, trimethoprim, and chloramphenicol.Among surface water isolates, 26% were resistant to at least one class of antimicrobials, and 11% were multidrug-resistant (MDR. In wastewater, the proportions of AMR/MDR E. coli were 76%/62% at HCIs, 69%/19% at the airport WWTP, and 37%/27% and 31%/20% in mWWTP influents and effluents, respectively. Median concentrations of MDR E. coli were 2.2×10(2, 4.0×10(4, 1.8×10(7, and 4.1×10(7 cfu/l in surface water, WWTP effluents, WWTP influents and HCI wastewater, respectively. The different resistance types occurred with similar frequencies among E. coli from surface water and E. coli from municipal wastewater. By contrast, among E. coli from HCI wastewater, resistance to cefotaxime and resistance to ciprofloxacin were significantly overrepresented compared to E. coli from municipal wastewater and surface water. Most cefotaxime-resistant E. coliisolates produced ESBL. In two of the mWWTP, ESBL-producing variants were detected that were identical with respect to phylogenetic group, sequence type, AMR-profile, and ESBL-genotype to variants from HCI wastewater discharged onto the same sewer and sampled on the same day (A1/ST23/CTX-M-1, B23/ST131/CTX-M-15, D2/ST405/CTX-M-15.In
Prevalence of blaTEM , blaSHV and blaCTX-M genes in clinical isolates of Escherichia coli and Klebsiella pneumoniae from Northeast India

Directory of Open Access Journals (Sweden)

Arijit Bora

2014-01-01

Full Text Available Aim: This study was carried out to determine the presence of blaTEM , blaSHV and blaCTX-M genes in extended-spectrum β-lactamase (ESBL producing Escherichia coli (E. coli and Klebsiella pneumoniae (K. pneumoniae at a tertiary care referral hospital in Northeast India. Materials and Methods: A total of 270 E. coli and 219 K. pneumoniae isolates were recovered during the period between August 2009 and July 2010. Kirby-Bauer disk diffusion method was performed to determine the antibiotic resistance pattern. Screening and phenotypic confirmatory test for ESBL production were performed using standard disc diffusion methods. Each of the initial ESBL screening test isolate was investigated for the presence of blaTEM , blaSHV and blaCTX-M genes via polymerase chain reaction (PCR using gene-specific primers. Results: Phenotypic confirmatory test able to detect ESBL production in 73.58% of E. coli and 67.24% of K. pneumoniae. However, PCR amplification showed the presence of one or more ESBL genes in each of the initial ESBL screening positive isolate. Among three ESBL genotypes, the most prevalent genotype was found to be blaCTX-M in E. coli (88.67% and blaTEM in K. pneumoniae (77.58% ESBL producing isolates. Majority of ESBL producing isolates possess more than one ESBL genes. Conclusion: This study constituted a primer report on high prevalence of blaTEM and blaCTX-M genes in ESBL producing isolates of E. coli and K. pneumoniae and denotes the need of more extensive studies on these antibiotic genes to determine the magnitude of the problem of antibiotic resistance exiting in this locality.

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