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Sample records for coli strains cft073

  1. A virulent parent with probiotic progeny: comparative genomics of Escherichia coli strains CFT073, Nissle 1917 and ABU 83972

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    Vejborg, Rebecca Munk; Friis, Carsten; Hancock, Viktoria

    2010-01-01

    ) with the highly virulent uropathogen CFT073. Only relatively minor genetic variations were found between the isolates, suggesting that the three strains may have originated from the same virulent ancestral parent. Interestingly, Nissle 1917 (a gut commensal strain) was more similar to CFT073 with respect...

  2. Functional genomics of probiotic Escherichia coli Nissle 1917 and 83972, and UPEC strain CFT073: comparison of transcriptomes, growth and biofilm formation.

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    Hancock, Viktoria; Vejborg, Rebecca Munk; Klemm, Per

    2010-12-01

    Strain CFT073 is a bona fide uropathogen, whereas strains 83972 and Nissle 1917 are harmless probiotic strains of urinary tract and faecal origin, respectively. Despite their different environmental origins and dispositions the three strains are very closely related and the ancestors of 83972 and Nissle 1917 must have been very similar to CFT073. Here, we report the first functional genome profiling of Nissle 1917 and the first biofilm profiling of a uropathogen. Transcriptomic profiling revealed that Nissle 1917 expressed many UPEC-associated genes and showed that the active genomic profiles of the three strains are closely related. The data demonstrate that the distance from a pathogen to a probiotic strain can be surprisingly short. We demonstrate that Nissle 1917, in spite of its intestinal niche origin, grows well in urine, and is a good biofilm former in this medium in which it also out-competes CFT073 during planktonic growth. The role in biofilm formation of three up-regulated genes, yhaK, yhcN and ybiJ, was confirmed by knockout mutants in Nissle 1917 and CFT073. Two of these mutants CFT073∆yhcN and CFT073∆ybiJ had significantly reduced motility compared with the parent strain, arguably accounting for the impaired biofilm formation. Although the three strains have very different strategies vis-à-vis the human host their functional gene profiles are surprisingly similar. It is also interesting to note that the only two Escherichia coli strains used as probiotics are in fact deconstructed pathogens.

  3. Genome reannotation of Escherichia coli CFT073 with new insights into virulence

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    Hu Gang-Qing

    2009-11-01

    Full Text Available Abstract Background As one of human pathogens, the genome of Uropathogenic Escherichia coli strain CFT073 was sequenced and published in 2002, which was significant in pathogenetic bacterial genomics research. However, the current RefSeq annotation of this pathogen is now outdated to some degree, due to missing or misannotation of some essential genes associated with its virulence. We carried out a systematic reannotation by combining automated annotation tools with manual efforts to provide a comprehensive understanding of virulence for the CFT073 genome. Results The reannotation excluded 608 coding sequences from the RefSeq annotation. Meanwhile, a total of 299 coding sequences were newly added, about one third of them are found in genomic island (GI regions while more than one fifth of them are located in virulence related regions pathogenicity islands (PAIs. Furthermore, there are totally 341 genes were relocated with their translational initiation sites (TISs, which resulted in a high quality of gene start annotation. In addition, 94 pseudogenes annotated in RefSeq were thoroughly inspected and updated. The number of miscellaneous genes (sRNAs has been updated from 6 in RefSeq to 46 in the reannotation. Based on the adjustment in the reannotation, subsequent analysis were conducted by both general and case studies on new virulence factors or new virulence-associated genes that are crucial during the urinary tract infections (UTIs process, including invasion, colonization, nutrition uptaking and population density control. Furthermore, miscellaneous RNAs collected in the reannotation are believed to contribute to the virulence of strain CFT073. The reannotation including the nucleotide data, the original RefSeq annotation, and all reannotated results is freely available via http://mech.ctb.pku.edu.cn/CFT073/. Conclusion As a result, the reannotation presents a more comprehensive picture of mechanisms of uropathogenicity of UPEC strain CFT073

  4. RpoS contributes to phagocyte oxidase-mediated stress resistance during urinary tract infection by Escherichia coli CFT073.

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    Hryckowian, Andrew J; Welch, Rodney A

    2013-02-12

    Uropathogenic Escherichia coli (UPEC) is the most common causative agent of community-acquired urinary tract infection (UTI). In order to cause UTI, UPEC must endure stresses ranging from nutrient limitation to host immune components. RpoS (σ(S)), the general stress response sigma factor, directs gene expression under a variety of inhibitory conditions. Our study of rpoS in UPEC strain CFT073 began after we discovered an rpoS-frameshift mutation in one of our laboratory stocks of "wild-type" CFT073. We demonstrate that an rpoS-deletion mutation in CFT073 leads to a colonization defect during UTI of CBA/J mice at 48 hours postinfection (hpi). There is no difference between the growth rates of CFT073 and CFT073 rpoS in urine. This indicates that rpoS is needed for replication and survival in the host rather than being needed to address limitations imposed by urine nutrients. Consistent with previous observations in E. coli K-12, CFT073 rpoS is more sensitive to oxidative stress than the wild type. We demonstrate that peroxide levels are elevated in voided urine from CFT073-infected mice compared to urine from mock-infected mice, which supports the notion that oxidative stress is generated by the host in response to UPEC. In mice that lack phagocyte oxidase, the enzyme complex expressed by phagocytes that produces superoxide, the competitive defect of CFT073 rpoS in bladder colonization is lost. These results demonstrate that σ(S) is important for UPEC survival under conditions of phagocyte oxidase-generated stress during UTI. Though σ(S) affects the pathogenesis of other bacterial species, this is the first work that directly implicates σ(S) as important for UPEC pathogenesis. UPEC must cope with a variety of stressful conditions in the urinary tract during infection. RpoS (σ(S)), the general stress response sigma factor, is known to direct the expression of many genes under a variety of stressful conditions in laboratory-adapted E. coli K-12. Here, we show that

  5. Functional genomics of probiotic Escherichia coli Nissle 1917 and 83972, and UPEC strain CFT073: comparison of transcriptomes, growth and biofilm formation

    DEFF Research Database (Denmark)

    Hancock, Viktoria; Vejborg, Rebecca Munk; Klemm, Per

    2010-01-01

    and Nissle 1917 must have been very similar to CFT073. Here, we report the first functional genome profiling of Nissle 1917 and the first biofilm profiling of a uropathogen. Transcriptomic profiling revealed that Nissle 1917 expressed many UPEC-associated genes and showed that the active genomic profiles...

  6. dsdA Does Not Affect Colonization of the Murine Urinary Tract by Escherichia coli CFT073.

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    Andrew J Hryckowian

    Full Text Available The urinary tract environment provides many conditions that deter colonization by microorganisms. D-serine is thought to be one of these stressors and is present at high concentrations in urine. D-serine interferes with L-serine and pantothenate metabolism and is bacteriostatic to many species. Uropathogenic Escherichia coli commonly possess the dsdCXA genetic locus, which allows them to use D-serine as a sole carbon, nitrogen, and energy source. It was previously reported that in the model UPEC strain CFT073, a dsdA mutant outcompetes wild type in the murine model of urinary tract infection. This "hypercolonization" was used to propose a model whereby UPEC strains sense D-serine in the urinary tract and subsequently up-regulate genes necessary for pathogenesis. Here, we show that inactivation of dsdA does not lead to hypercolonization. We suggest that this previously observed effect is due to an unrecognized secondary mutation in rpoS and that some D-serine specific effects described in other studies may be affected by the rpoS status of the strains used. Inactivation of dsdA in the original clinical isolate of CFT073 gives CFT073 ΔdsdA a growth defect in human urine and renders it unable to grow on minimal medium containing D-serine as the sole carbon source. However, CFT073 ΔdsdA is able to colonize the urinary tracts of CBA/J mice indistinguishably from wild type. These findings indicate that D-serine catabolism, though it may play role(s during urinary tract infection, does not affect the ability of uropathogenic E. coli to colonize the murine urinary tract.

  7. The Analysis of Multiple Genome Comparisons in Genus Escherichia and Its Application to the Discovery of Uncharacterised Metabolic Genes in Uropathogenic Escherichia coli CFT073

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    William A. Bryant

    2009-01-01

    Full Text Available A survey of a complete gene synteny comparison has been carried out between twenty fully sequenced strains from the genus Escherichia with the aim of finding yet uncharacterised genes implicated in the metabolism of uropathogenic strains of E. coli (UPEC. Several sets of adjacent colinear genes have been identified which are present in all four UPEC included in this study (CFT073, F11, UTI89, and 536, annotated with putative metabolic functions, but are not found in any other strains considered. An operon closely homologous to that encoding the L-sorbose degradation pathway in Klebsiella pneumoniae has been identified in E. coli CFT073; this operon is present in all of the UPEC considered, but only in 7 of the other 16 strains. The operon's function has been confirmed by cloning the genes into E. coli DH5α and testing for growth on L-sorbose. The functional genomic approach combining in silico and in vitro work presented here can be used as a basis for the discovery of other uncharacterised genes contributing to bacterial survival in specific environments.

  8. BarA-UvrY two-component system regulates virulence of uropathogenic E. coli CFT073.

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    Palaniyandi, Senthilkumar; Mitra, Arindam; Herren, Christopher D; Lockatell, C Virginia; Johnson, David E; Zhu, Xiaoping; Mukhopadhyay, Suman

    2012-01-01

    Uropathogenic Escherichia coli (UPEC), a member of extraintestinal pathogenic E. coli, cause ∼80% of community-acquired urinary tract infections (UTI) in humans. UPEC initiates its colonization in epithelial cells lining the urinary tract with a complicated life cycle, replicating and persisting in intracellular and extracellular niches. Consequently, UPEC causes cystitis and more severe form of pyelonephritis. To further understand the virulence characteristics of UPEC, we investigated the roles of BarA-UvrY two-component system (TCS) in regulating UPEC virulence. Our results showed that mutation of BarA-UvrY TCS significantly decreased the virulence of UPEC CFT073, as assessed by mouse urinary tract infection, chicken embryo killing assay, and cytotoxicity assay on human kidney and uroepithelial cell lines. Furthermore, mutation of either barA or uvrY gene reduced the production of hemolysin, lipopolysaccharide (LPS), proinflammatory cytokines (TNF-α and IL-6) and chemokine (IL-8). The virulence phenotype was restored similar to that of wild-type by complementation of either barA or uvrY gene in trans. In addition, we discussed a possible link between the BarA-UvrY TCS and CsrA in positively and negatively controlling virulence in UPEC. Overall, this study provides the evidences for BarA-UvrY TCS regulates the virulence of UPEC CFT073 and may point to mechanisms by which virulence regulations are observed in different ways may control the long-term survival of UPEC in the urinary tract.

  9. BarA-UvrY two-component system regulates virulence of uropathogenic E. coli CFT073.

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    Senthilkumar Palaniyandi

    Full Text Available Uropathogenic Escherichia coli (UPEC, a member of extraintestinal pathogenic E. coli, cause ∼80% of community-acquired urinary tract infections (UTI in humans. UPEC initiates its colonization in epithelial cells lining the urinary tract with a complicated life cycle, replicating and persisting in intracellular and extracellular niches. Consequently, UPEC causes cystitis and more severe form of pyelonephritis. To further understand the virulence characteristics of UPEC, we investigated the roles of BarA-UvrY two-component system (TCS in regulating UPEC virulence. Our results showed that mutation of BarA-UvrY TCS significantly decreased the virulence of UPEC CFT073, as assessed by mouse urinary tract infection, chicken embryo killing assay, and cytotoxicity assay on human kidney and uroepithelial cell lines. Furthermore, mutation of either barA or uvrY gene reduced the production of hemolysin, lipopolysaccharide (LPS, proinflammatory cytokines (TNF-α and IL-6 and chemokine (IL-8. The virulence phenotype was restored similar to that of wild-type by complementation of either barA or uvrY gene in trans. In addition, we discussed a possible link between the BarA-UvrY TCS and CsrA in positively and negatively controlling virulence in UPEC. Overall, this study provides the evidences for BarA-UvrY TCS regulates the virulence of UPEC CFT073 and may point to mechanisms by which virulence regulations are observed in different ways may control the long-term survival of UPEC in the urinary tract.

  10. Altered Regulation of the Diguanylate Cyclase YaiC Reduces Production of Type 1 Fimbriae in a Pst Mutant of Uropathogenic Escherichia coli CFT073.

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    Crépin, Sébastien; Porcheron, Gaëlle; Houle, Sébastien; Harel, Josée; Dozois, Charles M

    2017-12-15

    The pst gene cluster encodes the phosphate-specific transport (Pst) system. Inactivation of the Pst system constitutively activates the two-component regulatory system PhoBR and attenuates the virulence of pathogenic bacteria. In uropathogenic Escherichia coli strain CFT073, attenuation by inactivation of pst is predominantly attributed to the decreased expression of type 1 fimbriae. However, the molecular mechanisms connecting the Pst system and type 1 fimbriae are unknown. To address this, a transposon library was constructed in the pst mutant, and clones were tested for a regain in type 1 fimbrial production. Among them, the diguanylate cyclase encoded by yaiC ( adrA in Salmonella ) was identified to connect the Pst system and type 1 fimbrial expression. In the pst mutant, the decreased expression of type 1 fimbriae is connected by the induction of yaiC This is predominantly due to altered expression of the FimBE-like recombinase genes ipuA and ipbA , affecting at the same time the inversion of the fim promoter switch ( fimS ). In the pst mutant, inactivation of yaiC restored fim -dependent adhesion to bladder cells and virulence. Interestingly, the expression of yaiC was activated by PhoB, since transcription of yaiC was linked to the PhoB-dependent phoA-psiF operon. As YaiC is involved in cyclic di-GMP (c-di-GMP) biosynthesis, an increased accumulation of c-di-GMP was observed in the pst mutant. Hence, the results suggest that one mechanism by which deletion of the Pst system reduces the expression of type 1 fimbriae is through PhoBR-mediated activation of yaiC , which in turn increases the accumulation of c-di-GMP, represses the fim operon, and, consequently, attenuates virulence in the mouse urinary tract infection model. IMPORTANCE Urinary tract infections (UTIs) are common bacterial infections in humans. They are mainly caused by uropathogenic Escherichia coli (UPEC). We previously showed that interference with phosphate homeostasis decreases the

  11. Comparative Genomics of Escherichia coli Strains Causing Urinary Tract Infections

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    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...... of different clinical backgrounds, i.e., urosepsis, pyelonephritis, cystitis, and asymptomatic bacteriuria (ABU), using comparative genomic hybridization analysis. A microarray based on 31 complete E. coli sequences was used. It emerged that there is little correlation between the genotypes of the strains...... disease categories were identified. Among these were two genomic islands, namely, pathogenicity island (PAI)-CFT073-serU and PAI-CFT073-pheU, which were significantly more associated with the pyelonephritis and urosepsis isolates than with the ABU and cystitis isolates. These two islands harbor genes...

  12. Transcriptomics and adaptive genomics of the asymptomatic bacteriuria Escherichia coli strain 83972

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    Hancock, Viktoria; Seshasayee, Aswin S.; Ussery, David

    2008-01-01

    Escherichia coli strains are the major cause of urinary tract infections in humans. Such strains can be divided into virulent, UPEC strains causing symptomatic infections, and asymptomatic, commensal-like strains causing asymptomatic bacteriuria, ABU. The best-characterized ABU strain is strain...... factors for the human urinary tract could be identified. Also, presence/absence data of the gene expression was used as an adaptive genomics tool to model the gene pool of 83972 using primarily UPEC strain CFT073 as a scaffold. In our analysis, 96% of the transcripts filtered present in strain 83972 can...

  13. Cefotaxime and Amoxicillin-Clavulanate Synergism against Extended-Spectrum-β-Lactamase-Producing Escherichia coli in a Murine Model of Urinary Tract Infection.

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    Rossi, B; Soubirou, J F; Chau, F; Massias, L; Dion, S; Lepeule, R; Fantin, B; Lefort, A

    2015-11-02

    We investigated the efficacies of cefotaxime (CTX) and amoxicillin (AMX)-clavulanate (CLA) (AMC) against extended-spectrum-β-lactamase (ESBL)-producing Escherichia coli in vitro and in a murine model of urinary tract infection (UTI). MICs, the checkerboard dilution method, and time-kill curves were used to explore the in vitro synergism between cefotaxime and amoxicillin-clavulanate against two isogenic E. coli strains-CFT073-RR and its transconjugant, CFT073-RR Tc bla(CTX-M-15)-harboring a bla(CTX-M-15) plasmid and a bla(OXA-1) plasmid. For in vivo experiments, mice were separately infected with each strain and treated with cefotaxime, amoxicillin, and clavulanate, alone or in combination, or imipenem, using therapeutic regimens reproducing time of free-drug concentrations above the MIC (fT≥MIC) values close to that obtained in humans. MICs of amoxicillin, cefotaxime, and imipenem were 4/>1,024, 0.125/1,024, and 0.5/0.5 mg/liter, for CFT073-RR and CFT073-RR Tc bla(CTX-M-15), respectively. The addition of 2 mg/liter of clavulanate (CLA) restored the susceptibility of CFT073-RR Tc bla(CTX-M-15) to CTX (MICs of the CTX-CLA combination, 0.125 mg/liter). The checkerboard dilution method and time-kill curves confirmed an in vitro synergy between amoxicillin-clavulanate and cefotaxime against CFT073-RR Tc bla(CTX-M-15). In vivo, this antibiotic combination was similarly active against both strains and as effective as imipenem. In conclusion, the cefotaxime and amoxicillin-clavulanate combination appear to be an effective, easy, and already available alternative to carbapenems for the treatment of UTI due to CTX-M-producing E. coli strains. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  14. Metabolic Modeling of Common Escherichia coli Strains in Human Gut Microbiome

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    Yue-Dong Gao

    2014-01-01

    Full Text Available The recent high-throughput sequencing has enabled the composition of Escherichia coli strains in the human microbial community to be profiled en masse. However, there are two challenges to address: (1 exploring the genetic differences between E. coli strains in human gut and (2 dynamic responses of E. coli to diverse stress conditions. As a result, we investigated the E. coli strains in human gut microbiome using deep sequencing data and reconstructed genome-wide metabolic networks for the three most common E. coli strains, including E. coli HS, UTI89, and CFT073. The metabolic models show obvious strain-specific characteristics, both in network contents and in behaviors. We predicted optimal biomass production for three models on four different carbon sources (acetate, ethanol, glucose, and succinate and found that these stress-associated genes were involved in host-microbial interactions and increased in human obesity. Besides, it shows that the growth rates are similar among the models, but the flux distributions are different, even in E. coli core reactions. The correlations between human diabetes-associated metabolic reactions in the E. coli models were also predicted. The study provides a systems perspective on E. coli strains in human gut microbiome and will be helpful in integrating diverse data sources in the following study.

  15. Escherichia coli Pathotypes Occupy Distinct Niches in the Mouse Intestine

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    Meador, Jessica P.; Caldwell, Matthew E.; Cohen, Paul S.

    2014-01-01

    Since the first step of the infection process is colonization of the host, it is important to understand how Escherichia coli pathogens successfully colonize the intestine. We previously showed that enterohemorrhagic O157:H7 strain E. coli EDL933 colonizes a niche in the streptomycin-treated mouse intestine that is distinct from that of human commensal strains, which explains how E. coli EDL933 overcomes colonization resistance imparted by some, but not all, commensal E. coli strains. Here we sought to determine if other E. coli pathogens use a similar strategy. We found that uropathogenic E. coli CFT073 and enteropathogenic E. coli E2348/69 occupy intestinal niches that are distinct from that of E. coli EDL933. In contrast, two enterohemorrhagic strains, E. coli EDL933 and E. coli Sakai, occupy the same niche, suggesting that strategies to prevent colonization by a given pathotype should be effective against other strains of the same pathotype. However, we found that a combination of commensal E. coli strains that can prevent colonization by E. coli EDL933 did not prevent colonization by E. coli CFT073 or E. coli E2348/69. Our results indicate that development of probiotics to target multiple E. coli pathotypes will be problematic, as the factors that govern niche occupation and hence stable colonization vary significantly among strains. PMID:24566621

  16. Molecular Characterization of the Vacuolating Autotransporter Toxin in Uropathogenic Escherichia coli.

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    Nichols, Katie B; Totsika, Makrina; Moriel, Danilo G; Lo, Alvin W; Yang, Ji; Wurpel, Daniël J; Rossiter, Amanda E; Strugnell, Richard A; Henderson, Ian R; Ulett, Glen C; Beatson, Scott A; Schembri, Mark A

    2016-05-15

    The vacuolating autotransporter toxin (Vat) contributes to uropathogenic Escherichia coli (UPEC) fitness during systemic infection. Here, we characterized Vat and investigated its regulation in UPEC. We assessed the prevalence of vat in a collection of 45 UPEC urosepsis strains and showed that it was present in 31 (68%) of the isolates. The isolates containing the vat gene corresponded to three major E. coli sequence types (ST12, ST73, and ST95), and these strains secreted the Vat protein. Further analysis of the vat genomic locus identified a conserved gene located directly downstream of vat that encodes a putative MarR-like transcriptional regulator; we termed this gene vatX The vat-vatX genes were present in the UPEC reference strain CFT073, and reverse transcriptase PCR (RT-PCR) revealed that the two genes are cotranscribed. Overexpression of vatX in CFT073 led to a 3-fold increase in vat gene transcription. The vat promoter region contained three putative nucleation sites for the global transcriptional regulator histone-like nucleoid structuring protein (H-NS); thus, the hns gene was mutated in CFT073 (to generate CFT073 hns). Western blot analysis using a Vat-specific antibody revealed a significant increase in Vat expression in CFT073 hns compared to that in wild-type CFT073. Direct H-NS binding to the vat promoter region was demonstrated using purified H-NS in combination with electrophoresis mobility shift assays. Finally, Vat-specific antibodies were detected in plasma samples from urosepsis patients infected by vat-containing UPEC strains, demonstrating that Vat is expressed during infection. Overall, this study has demonstrated that Vat is a highly prevalent and tightly regulated immunogenic serine protease autotransporter protein of Enterobacteriaceae (SPATE) secreted by UPEC during infection. Uropathogenic Escherichia coli (UPEC) is the major cause of hospital- and community-acquired urinary tract infections. The vacuolating autotransporter toxin (Vat

  17. Possible involvement of Mycoplasma hominis in inhibiting the formation of biofilms by uropathogenic Escherichia coli (UPEC).

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    Oh, Sangnam; Go, Gwang-Woong; Choi, Nag-Jin; Oh, Sejong; Kim, Younghoon

    2013-01-01

    Here we examined the involvement of Mycoplasma hominis in the formation of biofilms by uropathogenic Escherichia coli (UPEC) strain CFT073. Initially, we thought that M. hominis does not affect the fitness of UPEC, including the growth and production of signaling molecules, such as autoinducer-2 and indole. We found, however, that the presence of M. hominis significantly decreased the degree of biofilm formation by UPEC CFT073 (approximately a 60% reduction for 10(5) ccu/mL of M. hominis as compared with UPEC alone). We also found that it had a slight effect in inhibiting the attachment and cytotoxicity of UPEC CFT073. These findings are specific to these UPEC strains rather than to enterohemorrhagic E. coli (EHEC) strains, found in normal intestinal flora. In addition, we performed whole-transcriptome profiling and quantitative real-time polymerase chain reaction (qRT-PCR) analysis. This indicated that the PhoPQ system and the anti-termination protein (encoded by ybcQ) were involved in the reduction of biofilm formation by M. hominis (corroborated by qRT-PCR). Furthermore, our results indicate that M. hominis raises the degree of transcription of toxin genes, including hha and pasT. Hence, we suggest a possible role of M. hominis in affecting the formation of biofilms by UPEC in the urinary tract.

  18. Uropathogenic Escherichia coli Metabolite-Dependent Quiescence and Persistence May Explain Antibiotic Tolerance during Urinary Tract Infection.

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    Leatham-Jensen, Mary P; Mokszycki, Matthew E; Rowley, David C; Deering, Robert; Camberg, Jodi L; Sokurenko, Evgeni V; Tchesnokova, Veronika L; Frimodt-Møller, Jakob; Krogfelt, Karen A; Leth Nielsen, Karen; Frimodt-Møller, Niels; Sun, Gongqin; Cohen, Paul S

    2016-01-01

    In the present study, it is shown that although Escherichia coli CFT073, a human uropathogenic (UPEC) strain, grows in liquid glucose M9 minimal medium, it fails to grow on glucose M9 minimal medium agar plates seeded with ≤10(6) CFU. The cells on glucose plates appear to be in a "quiescent" state that can be prevented by various combinations of lysine, methionine, and tyrosine. Moreover, the quiescent state is characteristic of ~80% of E. coli phylogenetic group B2 multilocus sequence type 73 strains, as well as 22.5% of randomly selected UPEC strains isolated from community-acquired urinary tract infections in Denmark. In addition, E. coli CFT073 quiescence is not limited to glucose but occurs on agar plates containing a number of other sugars and acetate as sole carbon sources. It is also shown that a number of E. coli CFT073 mini-Tn5 metabolic mutants (gnd, gdhA, pykF, sdhA, and zwf) are nonquiescent on glucose M9 minimal agar plates and that quiescence requires a complete oxidative tricarboxylic acid (TCA) cycle. In addition, evidence is presented that, although E. coli CFT073 quiescence and persistence in the presence of ampicillin are alike in that both require a complete oxidative TCA cycle and each can be prevented by amino acids, E. coli CFT073 quiescence occurs in the presence or absence of a functional rpoS gene, whereas maximal persistence requires a nonfunctional rpoS. Our results suggest that interventions targeting specific central metabolic pathways may mitigate UPEC infections by interfering with quiescence and persistence. IMPORTANCE Recurrent urinary tract infections (UTIs) affect 10 to 40% of women. In up to 77% of those cases, the recurrent infections are caused by the same uropathogenic E. coli (UPEC) strain that caused the initial infection. Upon infection of urothelial transitional cells in the bladder, UPEC appear to enter a nongrowing quiescent intracellular state that is thought to serve as a reservoir responsible for recurrent

  19. Uropathogenic Escherichia coli Metabolite-Dependent Quiescence and Persistence May Explain Antibiotic Tolerance during Urinary Tract Infection

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    Leatham-Jensen, Mary P.; Mokszycki, Matthew E.; Rowley, David C.; Deering, Robert; Camberg, Jodi L.; Sokurenko, Evgeni V.; Tchesnokova, Veronika L.; Frimodt-Møller, Jakob; Leth Nielsen, Karen; Sun, Gongqin

    2016-01-01

    ABSTRACT In the present study, it is shown that although Escherichia coli CFT073, a human uropathogenic (UPEC) strain, grows in liquid glucose M9 minimal medium, it fails to grow on glucose M9 minimal medium agar plates seeded with ≤106 CFU. The cells on glucose plates appear to be in a “quiescent” state that can be prevented by various combinations of lysine, methionine, and tyrosine. Moreover, the quiescent state is characteristic of ~80% of E. coli phylogenetic group B2 multilocus sequence type 73 strains, as well as 22.5% of randomly selected UPEC strains isolated from community-acquired urinary tract infections in Denmark. In addition, E. coli CFT073 quiescence is not limited to glucose but occurs on agar plates containing a number of other sugars and acetate as sole carbon sources. It is also shown that a number of E. coli CFT073 mini-Tn5 metabolic mutants (gnd, gdhA, pykF, sdhA, and zwf) are nonquiescent on glucose M9 minimal agar plates and that quiescence requires a complete oxidative tricarboxylic acid (TCA) cycle. In addition, evidence is presented that, although E. coli CFT073 quiescence and persistence in the presence of ampicillin are alike in that both require a complete oxidative TCA cycle and each can be prevented by amino acids, E. coli CFT073 quiescence occurs in the presence or absence of a functional rpoS gene, whereas maximal persistence requires a nonfunctional rpoS. Our results suggest that interventions targeting specific central metabolic pathways may mitigate UPEC infections by interfering with quiescence and persistence. IMPORTANCE Recurrent urinary tract infections (UTIs) affect 10 to 40% of women. In up to 77% of those cases, the recurrent infections are caused by the same uropathogenic E. coli (UPEC) strain that caused the initial infection. Upon infection of urothelial transitional cells in the bladder, UPEC appear to enter a nongrowing quiescent intracellular state that is thought to serve as a reservoir responsible

  20. Global gene expression profiling of asymptomatic bacteriuria Escherichia coli during biofilm growth in human urine

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    Hancock, Viktoria; Klemm, Per

    2007-01-01

    Urinary tract infection (UTI) is an important health problem worldwide, with many millions of cases each year, and Escherichia coli is the most common organism causing UTI in humans. Also, E. coli is responsible for most infections in patients with chronic indwelling bladder catheter. The two...... asymptomatic bacteriuria (ABU) E. coli strains 83972 and VR50 are significantly better biofilm formers in their natural growth medium, human urine, than the two uropathogenic E. coli isolates CFT073 and 536. We used DNA microarrays to monitor the expression profile during biofilm growth in urine of the two ABU...

  1. Escherichia coli O78 isolated from septicemic lambs shows high pathogenicity in a zebrafish model.

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    Kjelstrup, Cecilie K; Barber, Amelia E; Norton, J Paul; Mulvey, Matthew A; L'Abée-Lund, Trine M

    2017-01-25

    The pathogenicity of Escherichia coli O78 strain K46, originally isolated from an outbreak of septicemia in neonatal lambs, was investigated in zebrafish embryo and murine models of infection. Its biofilm potential, cellulose production, and the expression of type 1 pili and curli fimbriae were measured by in vitro assays. The strain was highly pathogenic in the zebrafish embryo model of infection, where it killed all embryos within 24 h post inoculation (hpi) at doses as low as 1000 colony forming units. Zebrafish embryos inoculated with similar doses of commensal E. coli strains showed no signs of disease, and cleared the bacteria within 24 h. E. coli K46 colonized the murine gut at the same level as the uropathogenic E. coli (UPEC) reference strain CFT073 in CBA/J mice after oral inoculation, but infected the murine bladder significantly less than CFT073 after transurethral inoculation. Type 1 pili were clearly expressed by E. coli K46, while curli fimbriae and cellulose production were weakly expressed. The ability to produce biofilm varied in different growth media, but overall E. coli K46 was a poorer biofilm producer compared to the reference strain E. coli UTI89. In conclusion, the zebrafish lethality model provides further evidence that E. coli K46 is highly pathogenic and might be useful in future studies to identify bacterial virulence factors.

  2. Epigenetic Mechanisms Regulate Innate Immunity against Uropathogenic and Commensal-Like Escherichia coli in the Surrogate Insect Model Galleria mellonella.

    Science.gov (United States)

    Heitmueller, Miriam; Billion, André; Dobrindt, Ulrich; Vilcinskas, Andreas; Mukherjee, Krishnendu

    2017-10-01

    Innate-immunity-related genes in humans are activated during urinary tract infections (UTIs) caused by pathogenic strains of Escherichia coli but are suppressed by commensals. Epigenetic mechanisms play a pivotal role in the regulation of gene expression in response to environmental stimuli. To determine whether epigenetic mechanisms can explain the different behaviors of pathogenic and commensal bacteria, we infected larvae of the greater wax moth, Galleria mellonella , a widely used model insect host, with a uropathogenic E. coli (UPEC) strain that causes symptomatic UTIs in humans or a commensal-like strain that causes asymptomatic bacteriuria (ABU). Infection with the UPEC strain (CFT073) was more lethal to larvae than infection with the attenuated ABU strain (83972) due to the recognition of each strain by different Toll-like receptors, ultimately leading to differential DNA/RNA methylation and histone acetylation. We used next-generation sequencing and reverse transcription (RT)-PCR to correlate epigenetic changes with the induction of innate-immunity-related genes. Transcriptomic analysis of G. mellonella larvae infected with E. coli strains CFT073 and 83972 revealed strain-specific variations in the class and expression levels of genes encoding antimicrobial peptides, cytokines, and enzymes controlling DNA methylation and histone acetylation. Our results provide evidence for the differential epigenetic regulation of transcriptional reprogramming by UPEC and ABU strains of E. coli in G. mellonella larvae, which may be relevant to understanding the different behaviors of these bacterial strains in the human urinary tract. Copyright © 2017 American Society for Microbiology.

  3. Plasmidic qnrA3 enhances Escherichia coli fitness in absence of antibiotic exposure.

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    Adrien Michon

    Full Text Available The widespread presence of plasmid-mediated quinolone resistance determinants, particularly qnr genes, has become a current issue. By protecting DNA-gyrase from quinolones, Qnr proteins confer a low level quinolone resistance that is not sufficient to explain their emergence. Since Qnr proteins were hypothesized to act as DNA-binding protein regulators, qnr genes could have emerged by providing a selective advantage other than antibiotic resistance. We investigated host fitness of Escherichia coli isogenic strains after acquisition of the qnrA3 gene, inserted either alone onto a small plasmid (pBR322, or harbored on a large conjugative native plasmid, pHe96(qnrA3 found in a clinical isolate. The isogenic strains were derived from the susceptible E. coli CFT073, a virulent B2 group strain known to infect bladder and kidneys in a mouse model of pyelonephritis. In vitro experiments included growth analysis by automatic spectrophotometry and flow cytometry, and competitions with CFU enumeration. In vivo experiments included infection with each strain and pairwise competitions in absence of antimicrobial exposure. As controls for our experiments we used mutations known to reduce fitness (rpsL K42N mutation or to enhance fitness (tetA deletion in pBR322. E. coli CFT073 transformed with pBRAM(PBR322-qnrA3 had significantly higher maximal OD than E. coli CFT073 transformed with pBR322 or pBR322ΔtetA, and in vivo competitions were more often won by the qnrA3 carrying strain (24 victories vs. 9 loss among 42 competitions, p = 0.001. In contrast, when pHe96(qnrA3 was introduced by conjugation in E. coli CFT073, it exerted a fitness cost shown by an impaired growth observed in vitro and in vivo and a majority of lost competitions (33/35, p<0.0001. In conclusion, qnrA3 acquisition enhanced bacterial fitness, which may explain qnr emergence and suggests a regulation role of qnr. However, fitness was reduced when qnrA3 was inserted onto multidrug

  4. Intramacrophage survival of uropathogenic Escherichia coli: Differences between diverse clinical isolates and between mouse and human macrophages

    KAUST Repository

    Bokil, Nilesh J.

    2011-11-01

    Uropathogenic E. coli (UPEC) are the primary cause of urinary tract infections. Recent studies have demonstrated that UPEC can invade and replicate within epithelial cells, suggesting that this bacterial pathogen may occupy an intracellular niche within the host. Given that many intracellular pathogens target macrophages, we assessed the interactions between UPEC and macrophages. Colonization of the mouse bladder by UPEC strain CFT073 resulted in increased expression of myeloid-restricted genes, consistent with the recruitment of inflammatory macrophages to the site of infection. In in vitro assays, CFT073 was able to survive within primary mouse bone marrow-derived macrophages (BMM) up to 24h post-infection. Three additional well-characterized clinical UPEC isolates associated with distinct UTI symptomatologies displayed variable long-term survival within BMM. UPEC strains UTI89 and VR50, originally isolated from patients with cystitis and asymptomatic bacteriuria respectively, showed elevated bacterial loads in BMM at 24h post-infection as compared to CFT073 and the asymptomatic bacteriuria strain 83972. These differences did not correlate with differential effects on macrophage survival or initial uptake of bacteria. E. coli UTI89 localized to a Lamp1 + vesicular compartment within BMM. In contrast to survival within mouse BMM, intracellular bacterial loads of VR50 were low in both human monocyte-derived macrophages (HMDM) and in human T24 bladder epithelial cells. Collectively, these data suggest that some UPEC isolates may subvert macrophage anti-microbial pathways, and that host species differences may impact on intracellular UPEC survival. © 2011 Elsevier GmbH.

  5. Gene doctoring: a method for recombineering in laboratory and pathogenic Escherichia coli strains

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    Penn Charles W

    2009-12-01

    to unwanted secondary alterations to the chromosome. Conclusion We have developed a counter-selective recombineering technique for epitope tagging or for deleting genes in E. coli. We have demonstrated the versatility of the technique by modifying the chromosome of the enterohaemorrhagic O157:H7 (EHEC, uropathogenic CFT073 (UPEC, enteroaggregative O42 (EAEC and enterotoxigenic H10407 (ETEC E. coli strains as well as in K-12 laboratory strains.

  6. Gene doctoring: a method for recombineering in laboratory and pathogenic Escherichia coli strains

    Science.gov (United States)

    2009-01-01

    alterations to the chromosome. Conclusion We have developed a counter-selective recombineering technique for epitope tagging or for deleting genes in E. coli. We have demonstrated the versatility of the technique by modifying the chromosome of the enterohaemorrhagic O157:H7 (EHEC), uropathogenic CFT073 (UPEC), enteroaggregative O42 (EAEC) and enterotoxigenic H10407 (ETEC) E. coli strains as well as in K-12 laboratory strains. PMID:20003185

  7. Sigma factors in a thousand E. coli genomes

    DEFF Research Database (Denmark)

    Cook, Helen Victoria; Ussery, David

    2013-01-01

    , 2013), only less than half (983) are of sufficient quality to use in comparative genomic work. Unfortunately, even some of the ‘complete’ E. coli genomes are in pieces, and a few ‘draft’ genomes are good quality. Six of the seven known sigma factors in E. coli strain K‐12 are extremely well conserved......; the iron‐regulating sigma factor FecI (σ19) is missing in most genomes. Surprisingly, the E. coli strain CFT073 genome does not encode a functional RpoD (σ70), which is obviously essential, and this is likely due to poor genome assembly/annotation. We find a possible novel sigma factor present in more than...

  8. Individual and co-operative roles of lactic acid and hydrogen peroxide in the killing activity of enteric strain Lactobacillus johnsonii NCC933 and vaginal strain Lactobacillus gasseri KS120.1 against enteric, uropathogenic and vaginosis-associated pathogens.

    Science.gov (United States)

    Atassi, Fabrice; Servin, Alain L

    2010-03-01

    The mechanism underlying the killing activity of Lactobacillus strains against bacterial pathogens appears to be multifactorial. Here, we investigate the respective contributions of hydrogen peroxide and lactic acid in killing bacterial pathogens associated with the human vagina, urinary tract or intestine by two hydrogen peroxide-producing strains. In co-culture, the human intestinal strain Lactobacillus johnsonii NCC933 and human vaginal strain Lactobacillus gasseri KS120.1 strains killed enteric Salmonella enterica serovar Typhimurium SL1344, vaginal Gardnerella vaginalis DSM 4944 and urinary tract Escherichia coli CFT073 pathogens. The cell-free culture supernatants (CFCSs) produced the same reduction in SL1344, DSM 4944 and CFT073 viability, whereas isolated bacteria had no effect. The killing activity of CFCSs was heat-stable. In the presence of Dulbecco's modified Eagle's minimum essential medium inhibiting the lactic acid-dependent killing activity, CFCSs were less effective at killing of the pathogens. Catalase-treated CFCSs displayed a strong decreased activity. Tested alone, hydrogen peroxide triggered a concentration-dependent killing activity against all three pathogens. Lactic acid alone developed a killing activity only at concentrations higher than that present in CFCSs. In the presence of lactic acid at a concentration present in Lactobacillus CFCSs, hydrogen peroxide displayed enhanced killing activity. Collectively, these results demonstrate that for hydrogen peroxide-producing Lactobacillus strains, the main metabolites of Lactobacillus, lactic acid and hydrogen peroxide, act co-operatively to kill enteric, vaginosis-associated and uropathogenic pathogens.

  9. Uropathogenic Escherichia coli pathogenicity islands and other ExPEC virulence genes may contribute to the genome variability of enteroinvasive E. coli.

    Science.gov (United States)

    da Silva, Laís Cristina; de Mello Santos, Ana Carolina; Silva, Rosa Maria

    2017-03-16

    Enteroinvasive Escherichia coli (EIEC) may be the causative agent of part of those million cases of diarrhea illness reported worldwide every year and attributable to Shigella. That is because both enteropathogens have many common characteristics that difficult their identification either by traditional microbiological methods or by molecular tools used in the clinical laboratory settings. While Shigella has been extensively studied, EIEC remains barely characterized at the molecular level. Recent EIEC important outbreaks, apparently generating more life-threatening cases, have prompted us to screen EIEC for virulence traits usually related to extraintestinal pathogenic E. coli (ExPEC). That could explain the appearance of EIEC strains presenting higher virulence potential. EIEC strains were distributed mainly in three phylogroups in a serogroup-dependent manner. Serogroups O124, O136, O144, and O152 were exclusively classified in phylogroup A; O143 in group E; and O28ac and O29 in group B1. Only two serogroups showed diverse phylogenetic origin as follows: O164 was assigned to groups A, B1, C, and B2 (one strain each), and O167 in groups E (five strains), and A (one strain) (Table 1). Eleven of 20 virulence genes (VGs) searched were detected, and the majority of the 19 different VGs combinations found were serogroup-specific. Uropathogenic E. coli (UPEC) PAI genetic markers were detected in all EIEC strains. PAIs I J96 and II CFT073 were the most frequent (92.1 and 80.4%, respectively). PAI IV 536 was restricted to some serogroups from phylogroups A, B1 and E. PAI I CFT073 was uniquely detected in phylogroups B2 and E. A total of 45 (88%) strains presented multiple PAI markers (two to four). PAIs I J96 and II CFT073 were found together in 80% of strains. EIEC is a DEC pathovar that presents VGs and pathogenicity island genetic markers typically associated with ExPEC, especially UPEC. These features are distributed in a phylogenetic and serogroup-dependent manner

  10. Role of capsule and O antigen in the virulence of uropathogenic Escherichia coli.

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    Sohinee Sarkar

    Full Text Available Urinary tract infection (UTI is one of the most common bacterial infections in humans, with uropathogenic Escherichia coli (UPEC the leading causative organism. UPEC has a number of virulence factors that enable it to overcome host defenses within the urinary tract and establish infection. The O antigen and the capsular polysaccharide are two such factors that provide a survival advantage to UPEC. Here we describe the application of the rpsL counter selection system to construct capsule (kpsD and O antigen (waaL mutants and complemented derivatives of three reference UPEC strains: CFT073 (O6:K2:H1, RS218 (O18:K1:H7 and 1177 (O1:K1:H7. We observed that while the O1, O6 and O18 antigens were required for survival in human serum, the role of the capsule was less clear and linked to O antigen type. In contrast, both the K1 and K2 capsular antigens provided a survival advantage to UPEC in whole blood. In the mouse urinary tract, mutation of the O6 antigen significantly attenuated CFT073 bladder colonization. Overall, this study contrasts the role of capsule and O antigen in three common UPEC serotypes using defined mutant and complemented strains. The combined mutagenesis-complementation strategy can be applied to study other virulence factors with complex functions both in vitro and in vivo.

  11. Role of capsule and O antigen in the virulence of uropathogenic Escherichia coli.

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    Sarkar, Sohinee; Ulett, Glen C; Totsika, Makrina; Phan, Minh-Duy; Schembri, Mark A

    2014-01-01

    Urinary tract infection (UTI) is one of the most common bacterial infections in humans, with uropathogenic Escherichia coli (UPEC) the leading causative organism. UPEC has a number of virulence factors that enable it to overcome host defenses within the urinary tract and establish infection. The O antigen and the capsular polysaccharide are two such factors that provide a survival advantage to UPEC. Here we describe the application of the rpsL counter selection system to construct capsule (kpsD) and O antigen (waaL) mutants and complemented derivatives of three reference UPEC strains: CFT073 (O6:K2:H1), RS218 (O18:K1:H7) and 1177 (O1:K1:H7). We observed that while the O1, O6 and O18 antigens were required for survival in human serum, the role of the capsule was less clear and linked to O antigen type. In contrast, both the K1 and K2 capsular antigens provided a survival advantage to UPEC in whole blood. In the mouse urinary tract, mutation of the O6 antigen significantly attenuated CFT073 bladder colonization. Overall, this study contrasts the role of capsule and O antigen in three common UPEC serotypes using defined mutant and complemented strains. The combined mutagenesis-complementation strategy can be applied to study other virulence factors with complex functions both in vitro and in vivo.

  12. 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...

  13. DNA microarray-mediated transcriptional profiling of avian pathogenic Escherichia coli O2 strain E058 during its infection of chicken.

    Science.gov (United States)

    Gao, Qingqing; Xia, Le; Liu, Juanhua; Wang, Xiaobo; Gao, Song; Liu, Xiufan

    2016-11-01

    Avian pathogenic Escherichia coli (APEC) cause typical extraintestinal infections in poultry, including acute fatal septicemia, subacute pericarditis, and airsacculitis. These bacteria most often infect chickens, turkeys, ducks, and other avian species, and therefore pose a significant economic burden on the poultry industry worldwide. Few studies have analyzed the genome-wide transcriptional profile of APEC during infection in vivo. In this study, we examined the genome-wide transcriptional response of APEC O2 strain E058 in an in vivo chicken infection model to better understand the factors necessary for APEC colonization, growth, and survival in vivo. An Affymetrix multigenome DNA microarray, which contains most of the genomic open reading frames of E. coli K-12 strain MG1655, uropathogenic E. coli strain CFT073, and E. coli O157:H7 strain EDL 933, was used to profile the gene expression in APEC E058. We identified the in vivo transcriptional response of APEC E058 bacteria collected directly from the blood of infected chickens. Significant differences in expression levels were detected between the in vivo expression profile and the in vitro expression profile in LB medium. The genes highly expressed during infection were involved in metabolism, iron acquisition or transport, virulence, response to stress, and biological regulation. The reliability of the microarray data was confirmed by performing quantitative real-time PCR on 12 representative genes. Moreover, several significantly upregulated genes, including yjiY, sodA, phoB and spy, were selected to study their role in APEC pathogenesis. The data will help to better understand the mechanisms of APEC pathogenesis. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Small Intestine Early Innate Immunity Response during Intestinal Colonization by Escherichia coli Depends on Its Extra-Intestinal Virulence Status.

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    Jérôme Tourret

    Full Text Available Uropathogenic Escherichia coli (UPEC strains live as commensals in the digestive tract of the host, but they can also initiate urinary tract infections. The aim of this work was to determine how a host detects the presence of a new UPEC strain in the digestive tract. Mice were orally challenged with UPEC strains 536 and CFT073, non-pathogenic strain K12 MG1655, and ΔPAI-536, an isogenic mutant of strain 536 lacking all 7 pathogenicity islands whose virulence is drastically attenuated. Intestinal colonization was measured, and cytokine expression was determined in various organs recovered from mice after oral challenge. UPEC strain 536 efficiently colonized the mouse digestive tract, and prior Enterobacteriaceae colonization was found to impact strain 536 colonization efficiency. An innate immune response, detected as the production of TNFα, IL-6 and IL-10 cytokines, was activated in the ileum 48 hours after oral challenge with strain 536, and returned to baseline within 8 days, without a drop in fecal pathogen load. Although inflammation was detected in the ileum, histology was normal at the time of cytokine peak. Comparison of cytokine secretion 48h after oral gavage with E. coli strain 536, CFT073, MG1655 or ΔPAI-536 showed that inflammation was more pronounced with UPECs than with non-pathogenic or attenuated strains. Pathogenicity islands also seemed to be involved in host detection, as IL-6 intestinal secretion was increased after administration of E. coli strain 536, but not after administration of ΔPAI-536. In conclusion, UPEC colonization of the mouse digestive tract activates acute phase inflammatory cytokine secretion but does not trigger any pathological changes, illustrating the opportunistic nature of UPECs. This digestive tract colonization model will be useful for studying the factors controlling the switch from commensalism to pathogenicity.

  15. Small Intestine Early Innate Immunity Response during Intestinal Colonization by Escherichia coli Depends on Its Extra-Intestinal Virulence Status.

    Science.gov (United States)

    Tourret, Jérôme; Willing, Benjamin P; Croxen, Matthew A; Dufour, Nicolas; Dion, Sara; Wachtel, Sarah; Denamur, Erick; Finlay, B Brett

    2016-01-01

    Uropathogenic Escherichia coli (UPEC) strains live as commensals in the digestive tract of the host, but they can also initiate urinary tract infections. The aim of this work was to determine how a host detects the presence of a new UPEC strain in the digestive tract. Mice were orally challenged with UPEC strains 536 and CFT073, non-pathogenic strain K12 MG1655, and ΔPAI-536, an isogenic mutant of strain 536 lacking all 7 pathogenicity islands whose virulence is drastically attenuated. Intestinal colonization was measured, and cytokine expression was determined in various organs recovered from mice after oral challenge. UPEC strain 536 efficiently colonized the mouse digestive tract, and prior Enterobacteriaceae colonization was found to impact strain 536 colonization efficiency. An innate immune response, detected as the production of TNFα, IL-6 and IL-10 cytokines, was activated in the ileum 48 hours after oral challenge with strain 536, and returned to baseline within 8 days, without a drop in fecal pathogen load. Although inflammation was detected in the ileum, histology was normal at the time of cytokine peak. Comparison of cytokine secretion 48h after oral gavage with E. coli strain 536, CFT073, MG1655 or ΔPAI-536 showed that inflammation was more pronounced with UPECs than with non-pathogenic or attenuated strains. Pathogenicity islands also seemed to be involved in host detection, as IL-6 intestinal secretion was increased after administration of E. coli strain 536, but not after administration of ΔPAI-536. In conclusion, UPEC colonization of the mouse digestive tract activates acute phase inflammatory cytokine secretion but does not trigger any pathological changes, illustrating the opportunistic nature of UPECs. This digestive tract colonization model will be useful for studying the factors controlling the switch from commensalism to pathogenicity.

  16. The secreted autotransporter toxin (Sat) does not act as a virulence factor in the probiotic Escherichia coli strain Nissle 1917.

    Science.gov (United States)

    Toloza, Lorena; Giménez, Rosa; Fábrega, María Jose; Alvarez, Carina Shianya; Aguilera, Laura; Cañas, María Alexandra; Martín-Venegas, Raquel; Badia, Josefa; Baldomà, Laura

    2015-10-30

    Escherichia coli Nissle 1917 (EcN) is a probiotic used in the treatment of intestinal diseases. Although it is considered safe, EcN is closely related to the uropathogenic E. coli strain CFT073 and contains many of its predicted virulence elements. Thus, it is relevant to assess whether virulence-associated genes are functional in EcN. One of these genes encodes the secreted autotransporter toxin (Sat), a member of the serine protease autotransporters of Enterobacteriaceae (SPATEs) that are secreted following the type V autotransporter pathway. Sat is highly prevalent in certain E. coli pathogenic groups responsible for urinary and intestinal infections. In these pathogens Sat promotes cytotoxic effects in several lines of undifferentiated epithelial cells, but not in differentiated Caco-2 cells. Here we provide evidence that sat is expressed by EcN during the colonization of mouse intestine. The EcN protein is secreted as an active serine protease, with its 107 kDa-passenger domain released into the medium as a soluble protein. Expression of recombinant EcN Sat protein in strain HB101 increases paracellular permeability to mannitol in polarized Caco-2 monolayers. This effect, also reported for the Sat protein of diffusely adherent E. coli, is not observed when this protein is expressed in the EcN background. In addition, we show that EcN supernatants confer protection against Sat-mediated effects on paracellular permeability, thus indicating that other secreted EcN factors are able to prevent barrier disruption caused by pathogen-related factors. Sat is not required for intestinal colonization, but the EcNsat::cat mutant outcompetes wild-type EcN in the streptomycin-treated mouse model. Analysis of the presence of sat in 29 strains of the ECOR collection isolated from stools of healthy humans shows 34.8 % positives, with high prevalence of strains of the phylogenetic groups D and B2, related with extra-intestinal infections. Sat does not act as a virulence factor

  17. The efficacy of immediate versus delayed antibiotic administration on bacterial growth and biofilm production of selected strains of uropathogenic Escherichia coli and Pseudomonas aeruginosa

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    Leah Gandee

    2015-02-01

    Full Text Available Purpose The treatment of urinary tract infections (UTI with antibiotics is commonly used, but recurrence and antibiotic resistance have been growing and concerning clinicians. We studied whether the rapid onset of a protective biofilm may be responsible for the lack of effectiveness of antibiotics against selected bacteria. Materials and Methods Two established uropathogenic Escherichia coli strains, UTI89 and CFT073, and two Pseudomonas aeruginosa strains, PA01 and Boston-41501, were studied to establish a reliable biofilm formation process. Bacterial growth (BG was determined by optical density at 600 nm (OD 600 using a spectrophotometer, while biofilm formation (BF using crystal violet staining was measured at OD 550. Next, these bacterial strains were treated with clinically relevant antibiotics, ciprofloxacin HCl (200 ng/mL and 2 μg/mL, nitrofurantoin (20 μg/mL and 40 μg/mL and ampicillin (50 μg/mL at time points of 0 (T0 or after 6 hours of culture (T6. All measurements, including controls (bacteria -1% DMSO, were done in triplicates and repeated three times for consistency. Results The tested antibiotics effectively inhibited both BG and BF when administered at T0 for UPEC strains, but not when the antibiotic administration started 6 hours later. For Pseudomonas strains, only Ciprofloxacin was able to significantly inhibit bacterial growth at T0 but only at the higher concentration of 2 μg/mL for T6. Conclusion When established UPEC and Pseudomonas bacteria were allowed to culture for 6 hours before initialization of treatment, the therapeutic effect of selected antibiotics was greatly suppressed when compared to immediate treatment, probably as a result of the protective nature of the biofilm.

  18. Tumor-specific colonization, tissue distribution, and gene induction by probiotic Escherichia coli Nissle 1917 in live mice.

    Science.gov (United States)

    Stritzker, Jochen; Weibel, Stephanie; Hill, Philip J; Oelschlaeger, Tobias A; Goebel, Werner; Szalay, Aladar A

    2007-06-01

    Systemic administration of microorganisms into tumor-bearing mice revealed preferential accumulation in tumors in comparison to clearance in organs such as spleen and liver. Here we compared the efficiency of tumor-specific colonization of pathogenic Salmonella typhimurium strains 14028 and SL1344 to the enteroinvasive Escherichia coli 4608-58 strain and to the attenuated Salmonella flexneri 2a SC602 strain, as well as to the uropathogenic E. coli CFT073, the non-pathogenic E. coli Top10, and the probiotic E. coli Nissle 1917 strain. All strains colonized and replicated in tumors efficiently each resulting in more than 1 x 10(8) colony-forming units per gram tumor tissue. Colonization of spleen and liver were significantly lower when E. coli strains were used in comparison to S. typhimurium and the non-pathogenic strains did not colonize those organs at all. Further investigation of E. coli Nissle 1917 showed that no drastic differences in colonization and amplification were seen when immunocompetent and immunocompromised animals were used, and we were able to show that E. coli Nissle 1917 replicates at the border of live and necrotic tumor tissue. We also demonstrated exogenously applied L-arabinose-dependent gene activation in colonized tumors in live mice. These findings will prepare the way for bacterium-mediated controlled protein delivery to solid tumors.

  19. A Novel Two-Component Signaling System Facilitates Uropathogenic Escherichia coli's Ability to Exploit Abundant Host Metabolites

    Science.gov (United States)

    Cai, Wentong; Wannemuehler, Yvonne; Dell'Anna, Giuseppe; Nicholson, Bryon; Barbieri, Nicolle L.; Kariyawasam, Subhashinie; Feng, Yaping; Logue, Catherine M.; Nolan, Lisa K.; Li, Ganwu

    2013-01-01

    Two-component signaling systems (TCSs) are major mechanisms by which bacteria adapt to environmental conditions. It follows then that TCSs would play important roles in the adaptation of pathogenic bacteria to host environments. However, no pathogen-associated TCS has been identified in uropathogenic Escherichia coli (UPEC). Here, we identified a novel TCS, which we termed KguS/KguR (KguS: α-ketoglutarate utilization sensor; KguR: α-ketoglutarate utilization regulator) in UPEC CFT073, a strain isolated from human pyelonephritis. kguS/kguR was strongly associated with UPEC but was found only rarely among other E. coli including commensal and intestinal pathogenic strains. An in vivo competition assay in a mouse UTI model showed that deletion of kguS/kguR in UPEC CFT073 resulted in a significant reduction in its colonization of the bladders and kidneys of mice, suggesting that KguS/KguR contributed to UPEC fitness in vivo. Comparative proteomics identified the target gene products of KguS/KguR, and sequence analysis showed that TCS KguS/KguR and its targeted-genes, c5032 to c5039, are encoded on a genomic island, which is not present in intestinal pathogenic E. coli. Expression of the target genes was induced by α-ketoglutarate (α-KG). These genes were further shown to be involved in utilization of α-KG as a sole carbon source under anaerobic conditions. KguS/KguR contributed to the regulation of the target genes with the direct regulation by KguR verified using an electrophoretic mobility shift assay. In addition, oxygen deficiency positively modulated expression of kguS/kguR and its target genes. Taken altogether, this study describes the first UPEC-associated TCS that functions in controlling the utilization of α-ketoglutarate in vivo thereby facilitating UPEC adaptation to life inside the urinary tract. PMID:23825943

  20. A novel two-component signaling system facilitates uropathogenic Escherichia coli's ability to exploit abundant host metabolites.

    Directory of Open Access Journals (Sweden)

    Wentong Cai

    Full Text Available Two-component signaling systems (TCSs are major mechanisms by which bacteria adapt to environmental conditions. It follows then that TCSs would play important roles in the adaptation of pathogenic bacteria to host environments. However, no pathogen-associated TCS has been identified in uropathogenic Escherichia coli (UPEC. Here, we identified a novel TCS, which we termed KguS/KguR (KguS: α-ketoglutarate utilization sensor; KguR: α-ketoglutarate utilization regulator in UPEC CFT073, a strain isolated from human pyelonephritis. kguS/kguR was strongly associated with UPEC but was found only rarely among other E. coli including commensal and intestinal pathogenic strains. An in vivo competition assay in a mouse UTI model showed that deletion of kguS/kguR in UPEC CFT073 resulted in a significant reduction in its colonization of the bladders and kidneys of mice, suggesting that KguS/KguR contributed to UPEC fitness in vivo. Comparative proteomics identified the target gene products of KguS/KguR, and sequence analysis showed that TCS KguS/KguR and its targeted-genes, c5032 to c5039, are encoded on a genomic island, which is not present in intestinal pathogenic E. coli. Expression of the target genes was induced by α-ketoglutarate (α-KG. These genes were further shown to be involved in utilization of α-KG as a sole carbon source under anaerobic conditions. KguS/KguR contributed to the regulation of the target genes with the direct regulation by KguR verified using an electrophoretic mobility shift assay. In addition, oxygen deficiency positively modulated expression of kguS/kguR and its target genes. Taken altogether, this study describes the first UPEC-associated TCS that functions in controlling the utilization of α-ketoglutarate in vivo thereby facilitating UPEC adaptation to life inside the urinary tract.

  1. Escherichia coli-mediated impairment of ureteric contractility is uropathogenic E. coli specific.

    Science.gov (United States)

    Floyd, Rachel V; Upton, Mathew; Hultgren, Scott J; Wray, Susan; Burdyga, Theodor V; Winstanley, Craig

    2012-11-15

    Ureters are fundamental for keeping kidneys free from uropathogenic Escherichia coli (UPEC), but we have shown that 2 strains (J96 and 536) can subvert this role and reduce ureteric contractility. To determine whether this is (1) a widespread feature of UPEC, (2) exhibited only by UPEC, and (3) dependent upon type 1 fimbriae, we analyzed strains representing epidemiologically important multilocus sequence types ST131, ST73, and ST95 and non-UPEC E. coli. Contractility and calcium transients in intact rat ureters were compared between strains. Mannose and fim mutants were used to investigate the role of type 1 fimbriae. Non-UPEC had no significant effect on contractility, with a mean decrease after 8 hours of 8.8%, compared with 8.8% in controls. UPEC effects on contractility were strain specific, with decreases from 9.47% to 96.7%. Mannose inhibited the effects of the most potent strains (CFT073 and UTI89) but had variable effects among other UPEC strains. Mutation and complementation studies showed that the effects of the UTI89 cystitis isolate were fimH dependent. We find that (1) non-UPEC do not affect ureteric contractility, (2) impairment of contractility is a common feature of UPEC, and (3) the mechanism varies between strains, but for the most potent UPEC type 1 fimbriae are involved.

  2. Suppression subtractive hybridization identifies an autotransporter adhesin gene of E. coli IMT5155 specifically associated with avian pathogenic Escherichia coli (APEC).

    Science.gov (United States)

    Dai, Jianjun; Wang, Shaohui; Guerlebeck, Doreen; Laturnus, Claudia; Guenther, Sebastian; Shi, Zhenyu; Lu, Chengping; Ewers, Christa

    2010-09-09

    Extraintestinal pathogenic E. coli (ExPEC) represent a phylogenetically diverse group of bacteria which are implicated in a large range of infections in humans and animals. Although subgroups of different ExPEC pathotypes, including uropathogenic, newborn meningitis causing, and avian pathogenic E. coli (APEC) share a number of virulence features, there still might be factors specifically contributing to the pathogenesis of a certain subset of strains or a distinct pathotype. Thus, we made use of suppression subtractive hybridization and compared APEC strain IMT5155 (O2:K1:H5; sequence type complex 95) with human uropathogenic E. coli strain CFT073 (O6:K2:H5; sequence type complex 73) to identify factors which may complete the currently existing model of APEC pathogenicity and further elucidate the position of this avian pathotype within the whole ExPEC group. Twenty-eight different genomic loci were identified, which are present in IMT5155 but not in CFT073. One of these loci contained a gene encoding a putative autotransporter adhesin. The open reading frame of the gene spans a 3,498 bp region leading to a putative 124-kDa adhesive protein. A specific antibody was raised against this protein and expression of the adhesin was shown under laboratory conditions. Adherence and adherence inhibition assays demonstrated a role for the corresponding protein in adhesion to DF-1 chicken fibroblasts. Sequence analyses revealed that the flanking regions of the chromosomally located gene contained sequences of mobile genetic elements, indicating a probable spread among different strains by horizontal gene transfer. In accordance with this hypothesis, the adhesin was found to be present not only in different phylogenetic groups of extraintestinal pathogenic but also of commensal E. coli strains, yielding a significant association with strains of avian origin. We identified a chromosomally located autotransporter gene in a highly virulent APEC strain which confers increased

  3. Uropathogenic Escherichia coli metabolite-dependent quiescence and persistence may explain antibiotic tolerance during urinary tract infection

    DEFF Research Database (Denmark)

    Leatham-Jensen, Mary P.; Mokszycki, Matthew E.; Rowley, David C.

    2016-01-01

    ) are nonquiescent on glucose M9 minimal agar plates and that quiescence requires a complete oxidative tricarboxylic acid (TCA) cycle. In addition, evidence is presented that, although E. coli CFT073 quiescence and persistence in the presence of ampicillin are alike in that both require a complete oxidative TCA...

  4. 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...

  5. F9 fimbriae of uropathogenic Escherichia coli are expressed at low temperature and recognise Galβ1-3GlcNAc-containing glycans.

    Directory of Open Access Journals (Sweden)

    Daniël J Wurpel

    Full Text Available Uropathogenic Escherichia coli (UPEC is the leading causative agent of urinary tract infections (UTI in the developed world. Among the major virulence factors of UPEC, surface expressed adhesins mediate attachment and tissue tropism. UPEC strains typically possess a range of adhesins, with type 1 fimbriae and P fimbriae of the chaperone-usher class the best characterised. We previously identified and characterised F9 as a new chaperone-usher fimbrial type that mediates biofilm formation. However, the regulation and specific role of F9 fimbriae remained to be determined in the context of wild-type clinical UPEC strains. In this study we have assessed the distribution and genetic context of the f9 operon among diverse E. coli lineages and pathotypes and demonstrated that f9 genes are significantly more conserved in a UPEC strain collection in comparison to the well-defined E. coli reference (ECOR collection. In the prototypic UPEC strain CFT073, the global regulator protein H-NS was identified as a transcriptional repressor of f9 gene expression at 37°C through its ability to bind directly to the f9 promoter region. F9 fimbriae expression was demonstrated at 20°C, representing the first evidence of functional F9 fimbriae expression by wild-type E. coli. Finally, glycan array analysis demonstrated that F9 fimbriae recognise and bind to terminal Galβ1-3GlcNAc structures.

  6. Hydrogen production by recombinant Escherichia coli strains

    Science.gov (United States)

    Maeda, Toshinari; Sanchez‐Torres, Viviana; Wood, Thomas K.

    2012-01-01

    Summary The production of hydrogen via microbial biotechnology is an active field of research. Given its ease of manipulation, the best‐studied bacterium Escherichia coli has become a workhorse for enhanced hydrogen production through metabolic engineering, heterologous gene expression, adaptive evolution, and protein engineering. Herein, the utility of E. coli strains to produce hydrogen, via native hydrogenases or heterologous ones, is reviewed. In addition, potential strategies for increasing hydrogen production are outlined and whole‐cell systems and cell‐free systems are compared. PMID:21895995

  7. Sub-Terrahertz Spectroscopy of E.COLI Dna: Experiment, Statistical Model, and MD Simulations

    Science.gov (United States)

    Sizov, I.; Dorofeeva, T.; Khromova, T.; Gelmont, B.; Globus, T.

    2012-06-01

    We will present result of combined experimental and computational study of sub-THz absorption spectra from Escherichia coli (E.coli) DNA. Measurements were conducted using a Bruker FTIR spectrometer with a liquid helium cooled bolometer and a recently developed frequency domain sensor operating at room temperature, with spectral resolution of 0.25 cm-1 and 0.03 cm-1, correspondingly. We have earlier demonstrated that molecular dynamics (MD) simulation can be effectively applied for characterizing relatively small biological molecules, such as transfer RNA or small protein thioredoxin from E. coli , and help to understand and predict their absorption spectra. Large size of DNA macromolecules ( 5 million base pairs for E. coli DNA) prevents, however, direct application of MD simulation at the current level of computational capabilities. Therefore, by applying a second order Markov chain approach and Monte-Carlo technique, we have developed a new statistical model to construct DNA sequences from biological cells. These short representative sequences (20-60 base pairs) are built upon the most frequently repeated fragments (2-10 base pairs) in the original DNA. Using this new approach, we constructed DNA sequences for several non-pathogenic strains of E.coli, including a well-known strain BL21, uro-pathogenic strain, CFT073, and deadly EDL933 strain (O157:H7), and used MD simulations to calculate vibrational absorption spectra of these strains. Significant differences are clearly present in spectra of strains in averaged spectra and in all components for particular orientations. The mechanism of interaction of THz radiation with a biological molecule is studied by analyzing dynamics of atoms and correlation of local vibrations in the modeled molecule. Simulated THz vibrational spectra of DNA are compared with experimental results. With the spectral resolution of 0.1 cm-1 or better, which is now available in experiments, the very easy discrimination between different

  8. Sat, the secreted autotransporter toxin of uropathogenic Escherichia coli, is a vacuolating cytotoxin for bladder and kidney epithelial cells.

    Science.gov (United States)

    Guyer, Debra M; Radulovic, Suzana; Jones, Faye-Ellen; Mobley, Harry L T

    2002-08-01

    The secreted autotransporter toxin (Sat) of uropathogenic Escherichia coli exhibits cytopathic activity upon incubation with HEp-2 cells. We further investigated the effects of Sat on cell lines more relevant to the urinary tract, namely, those derived from bladder and kidney epithelium. Sat elicited elongation of cells and apparent loosening of cellular junctions upon incubation with Vero kidney cells. Additionally, incubation with Sat triggered significant vacuolation within the cytoplasm of both human bladder (CRL-1749) and kidney (CRL-1573) cell lines. This activity has been associated with only a few other known toxins. Following transurethral infection of CBA mice with a sat mutant, no reduction of CFU in urine, bladder, or kidney tissue was seen compared to that in mice infected with wild-type E. coli CFT073. However, significant histological changes were observed within the kidneys of mice infected with wild-type E. coli CFT073, including dissolution of the glomerular membrane and vacuolation of proximal tubule cells. Such damage was not observed in kidney sections of mice infected with a Sat-deficient mutant. These results indicate that Sat, a vacuolating cytotoxin expressed by uropathogenic E. coli CFT073, elicits defined damage to kidney epithelium during upper urinary tract infection and thus contributes to pathogenesis of urinary tract infection.

  9. 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....

  10. Antimicrobial resistance of non-clinical Escherichia coli strains from ...

    African Journals Online (AJOL)

    This study was carried out to determine resistance profiles of Escherichia coli strains isolated from clinically healthy chickens in Nsukka, southeast Nigeria. A total of 324 E. coli strains isolated from cloaca swabs from 390 chickens were tested against 16 antimicrobial agents using the disc diffusion method. The antibiotics ...

  11. Antibiotics susceptibility pattern of Escherichia coli strains isolated ...

    African Journals Online (AJOL)

    This study was carried out to determine the susceptibility of E coli strains isolated from broiler and layer chicken with colisepticemia to antibiotics used in poultry industry in the country. A total of fifty seven E. coli strains isolated from 43 broiler and14 layer farms with colisepticemia in Khartoum and Gezera state were ...

  12. IraL is an RssB anti-adaptor that stabilizes RpoS during logarithmic phase growth in Escherichia coli and Shigella.

    Science.gov (United States)

    Hryckowian, Andrew J; Battesti, Aurelia; Lemke, Justin J; Meyer, Zachary C; Welch, Rodney A

    2014-05-27

    RpoS (σ(S)), the general stress response sigma factor, directs the expression of genes under a variety of stressful conditions. Control of the cellular σ(S) concentration is critical for appropriately scaled σ(S)-dependent gene expression. One way to maintain appropriate levels of σ(S) is to regulate its stability. Indeed, σ(S) degradation is catalyzed by the ClpXP protease and the recognition of σ(S) by ClpXP depends on the adaptor protein RssB. Three anti-adaptors (IraD, IraM, and IraP) exist in Escherichia coli K-12; each interacts with RssB and inhibits RssB activity under different stress conditions, thereby stabilizing σ(S). Unlike K-12, some E. coli isolates, including uropathogenic E. coli strain CFT073, show comparable cellular levels of σ(S) during the logarithmic and stationary growth phases, suggesting that there are differences in the regulation of σ(S) levels among E. coli strains. Here, we describe IraL, an RssB anti-adaptor that stabilizes σ(S) during logarithmic phase growth in CFT073 and other E. coli and Shigella strains. By immunoblot analyses, we show that IraL affects the levels and stability of σ(S) during logarithmic phase growth. By computational and PCR-based analyses, we reveal that iraL is found in many E. coli pathotypes but not in laboratory-adapted strains. Finally, by bacterial two-hybrid and copurification analyses, we demonstrate that IraL interacts with RssB by a mechanism distinct from that used by other characterized anti-adaptors. We introduce a fourth RssB anti-adaptor found in E. coli species and suggest that differences in the regulation of σ(S) levels may contribute to host and niche specificity in pathogenic and nonpathogenic E. coli strains. Bacteria must cope with a variety of environmental conditions in order to survive. RpoS (σ(S)), the general stress response sigma factor, directs the expression of many genes under stressful conditions in both pathogenic and nonpathogenic Escherichia coli strains

  13. Transcriptional responses of uropathogenic Escherichia coli to increased environmental osmolality caused by salt or urea.

    Science.gov (United States)

    Withman, Benjamin; Gunasekera, Thusitha S; Beesetty, Pavani; Agans, Richard; Paliy, Oleg

    2013-01-01

    Uropathogenic Escherichia coli (UPEC) is the most common causative agent of urinary tract infections in humans. The majority of urinary infections develop via ascending route through the urethra, where bacterial cells come in contact with human urine prior to reaching the bladder or kidneys. Since urine contains significant amounts of inorganic ions and urea, it imposes osmotic and denaturing stresses on bacterial cells. In this study, we determined the transcriptional adaptive responses of UPEC strain CFT073 to the presence of 0.3 M NaCl or 0.6 M urea in the growth medium. The cell responses to these two osmolytes were drastically different. Although most of the genes of the osmotically inducible regulon were overexpressed in medium with salt, urea failed to stimulate osmotic stress response. At the same time, UPEC colonization genes encoding type 1 and F1C fimbriae and capsule biosynthesis were transcriptionally induced in the presence of urea but did not respond to increased salt concentration. We speculate that urea can potentially be sensed by uropathogenic bacteria to initiate infection program. In addition, several molecular chaperone genes were overexpressed in the presence of urea, whereas adding NaCl to the medium led to an upregulation of a number of anaerobic metabolism pathways.

  14. Human Milk Oligosaccharides Protect Bladder Epithelial Cells Against Uropathogenic Escherichia coli Invasion and Cytotoxicity

    Science.gov (United States)

    Lin, Ann E.; Autran, Chloe A.; Espanola, Sophia D.; Bode, Lars; Nizet, Victor

    2014-01-01

    The invasive pathogen uropathogenic Escherichia coli (UPEC) is the primary cause of urinary tract infections (UTIs). Recurrent infection that can progress to life-threatening renal failure has remained as a serious global health concern in infants. UPEC adheres to and invades bladder epithelial cells to establish infection. Studies have detected the presence of human milk oligosaccharides (HMOs) in urine of breast-fed, but not formula-fed, neonates. We investigated the mechanisms HMOs deploy to elicit protection in human bladder epithelial cells infected with UPEC CFT073, a prototypic urosepsis-associated strain. We found a significant reduction in UPEC internalization into HMO-pretreated epithelial cells without observing any significant effect in UPEC binding to these cells. This event coincides with a rapid decrease in host cell cytotoxicity, recognized by LIVE/DEAD staining and cell detachment, but independent of caspase-mediated or mitochondrial-mediated programmed cell death pathways. Further investigation revealed HMOs, and particularly the sialic acid-containing fraction, reduced UPEC-mediated MAPK and NF-κB activation. Collectively, our results indicate that HMOs can protect bladder epithelial cells from deleterious cytotoxic and proinflammatory effects of UPEC infection, and may be one contributing mechanism underlying the epidemiological evidence of reduced UTI incidence in breast-fed infants. PMID:23990566

  15. Type 1 fimbriae contribute to catheter-associated urinary tract infections caused by Escherichia coli.

    Science.gov (United States)

    Reisner, Andreas; Maierl, Mario; Jörger, Michael; Krause, Robert; Berger, Daniela; Haid, Andrea; Tesic, Dijana; Zechner, Ellen L

    2014-03-01

    Biofilm formation on catheters is thought to contribute to persistence of catheter-associated urinary tract infections (CAUTI), which represent the most frequent nosocomial infections. Knowledge of genetic factors for catheter colonization is limited, since their role has not been assessed using physicochemical conditions prevailing in a catheterized human bladder. The current study aimed to combine data from a dynamic catheterized bladder model in vitro with in vivo expression analysis for understanding molecular factors relevant for CAUTI caused by Escherichia coli. By application of the in vitro model that mirrors the physicochemical environment during human infection, we found that an E. coli K-12 mutant defective in type 1 fimbriae, but not isogenic mutants lacking flagella or antigen 43, was outcompeted by the wild-type strain during prolonged catheter colonization. The importance of type 1 fimbriae for catheter colonization was verified using a fimA mutant of uropathogenic E. coli strain CFT073 with human and artificial urine. Orientation of the invertible element (IE) controlling type 1 fimbrial expression in bacterial populations harvested from the colonized catheterized bladder in vitro suggested that the vast majority of catheter-colonizing cells (up to 88%) express type 1 fimbriae. Analysis of IE orientation in E. coli populations harvested from patient catheters revealed that a median level of ∼73% of cells from nine samples have switched on type 1 fimbrial expression. This study supports the utility of the dynamic catheterized bladder model for analyzing catheter colonization factors and highlights a role for type 1 fimbriae during CAUTI.

  16. 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

  17. Strain-dependent carotenoid productions in metabolically engineered Escherichia coli.

    Science.gov (United States)

    Chae, Han Seung; Kim, Kong-Hwan; Kim, Sun Chang; Lee, Pyung Cheon

    2010-12-01

    Seven Escherichia coli strains, which were metabolically engineered with carotenoid biosynthetic pathways, were systematically compared in order to investigate the strain-specific formation of carotenoids of structural diversity. C30 acyclic carotenoids, diaponeurosporene and diapolycopene were well produced in all E. coli strains tested. However, the C30 monocyclic diapotorulene formation was strongly strain dependent. Reduced diapotorulene formation was observed in the E. coli strain Top10, MG1655, and MDS42 while better formation was observed in the E. coli strain JM109, SURE, DH5a, and XL1-Blue. Interestingly, C40 carotenoids, which have longer backbones than C30 carotenoids, also showed strain dependency as C30 diapotorulene did. Quantitative analysis showed that the SURE strain was the best producer for C40 acyclic lycopene, C40 dicyclic β-carotene, and C30 monocyclic diapotorulene. Of the seven strains examined, the highest volumetric productivity for most of the carotenoids structures was observed in the recombinant SURE strain. In conclusion, we showed that recombinant hosts and carotenoid structures influenced carotenoid productions significantly, and this information can serve as the basis for the subsequent development of microorganisms for carotenoids of interest.

  18. Gentamicin resistance among Escherichia coli strains isolated in neonatal sepsis.

    Science.gov (United States)

    Hasvold, J; Bradford, L; Nelson, C; Harrison, C; Attar, M; Stillwell, T

    2013-01-01

    Neonatal sepsis is a significant cause of morbidity and mortality among term and preterm infants. Ampicillin and gentamicin are standard empiric therapy for early onset sepsis. Four cases of neonatal sepsis secondary to Escherichia coli (E. coli) found to be gentamicin resistant occurred within a five week period in one neonatal intensive care unit (NICU). To determine whether these cases could be tied to a single vector of transmission, and to more broadly evaluate the incidence of gentamicin resistant strains of E. coli in the neonatal population at our institution compared to other centers, we reviewed the charts of the four neonates (Infants A through D) and their mothers. The E. coli isolates were sent for Pulse Field Gel Electrophoresis (PFGE) to evaluate for genetic similarity between strains. We also reviewed all positive E. coli cultures from one NICU over a two year period. Infants A and B had genetically indistinguishable strains which matched that of urine and placental cultures of Infant B's mother. Infant C had a genetically distinct organism. Infant D, the identical twin of Infant C, did not have typing performed. Review of all cultures positive for E. coli at our institution showed a 12.9 percent incidence of gentamicin-resistance. A review of other studies showed that rates of resistance vary considerably by institution. We conclude that gentamicin-resistant E. coli is a relatively uncommon cause of neonatal sepsis, but should remain a consideration in patients who deteriorate despite initiation of empiric antibiotics.

  19. Identification of diarrheagenic Escherichia coli strains from avian organic fertilizers.

    Science.gov (United States)

    Puño-Sarmiento, Juan; Gazal, Luis Eduardo; Medeiros, Leonardo P; Nishio, Erick K; Kobayashi, Renata K T; Nakazato, Gerson

    2014-08-28

    The Brazilian poultry industry generates large amounts of organic waste, such as chicken litter, which is often used in agriculture. Among the bacteria present in organic fertilizer are members of the Enterobacteriaceae family. The objective of this study was to detect the presence of diarrheagenic Escherichia coli (DEC) strains in avian organic fertilizer, and assess the potential damage they can cause in humans due to antimicrobial resistance. The presence of DEC pathotypes and phylogenetic groups were detected by multiplex-PCR. Phenotypic assays, such as tests for adhesion, cytotoxicity activity, biofilm formation and especially antimicrobial susceptibility, were performed. Fifteen DEC strains from 64 E. coli were isolated. Among these, four strains were classified as enteropathogenic (EPEC; 6.2%), three strains as Shiga toxin-producing (STEC; 4.7%), 10 strains as enteroaggregative (EAEC; 12.5%), but two of these harbored the eaeA gene too. The low number of isolated strains was most likely due to the composting process, which reduces the number of microorganisms. These strains were able to adhere to HEp-2 and HeLa cells and produce Shiga-toxins and biofilms; in addition, some of the strains showed antimicrobial resistance, which indicates a risk of the transfer of resistance genes to human E. coli. These results showed that DEC strains isolated from avian organic fertilizers can cause human infections.

  20. Identification of Diarrheagenic Escherichia coli Strains from Avian Organic Fertilizers

    Directory of Open Access Journals (Sweden)

    Juan Puño-Sarmiento

    2014-08-01

    Full Text Available The Brazilian poultry industry generates large amounts of organic waste, such as chicken litter, which is often used in agriculture. Among the bacteria present in organic fertilizer are members of the Enterobacteriaceae family. The objective of this study was to detect the presence of diarrheagenic Escherichia coli (DEC strains in avian organic fertilizer, and assess the potential damage they can cause in humans due to antimicrobial resistance. The presence of DEC pathotypes and phylogenetic groups were detected by multiplex-PCR. Phenotypic assays, such as tests for adhesion, cytotoxicity activity, biofilm formation and especially antimicrobial susceptibility, were performed. Fifteen DEC strains from 64 E. coli were isolated. Among these, four strains were classified as enteropathogenic (EPEC; 6.2%, three strains as Shiga toxin-producing (STEC; 4.7%, 10 strains as enteroaggregative (EAEC; 12.5%, but two of these harbored the eaeA gene too. The low number of isolated strains was most likely due to the composting process, which reduces the number of microorganisms. These strains were able to adhere to HEp-2 and HeLa cells and produce Shiga-toxins and biofilms; in addition, some of the strains showed antimicrobial resistance, which indicates a risk of the transfer of resistance genes to human E. coli. These results showed that DEC strains isolated from avian organic fertilizers can cause human infections.

  1. Molecular characterization of the Escherichia coli asymptomatic bacteriuria strain 83972

    DEFF Research Database (Denmark)

    Klemm, Per; Hancock, Viktoria; Ulett, G.C.

    2006-01-01

    Escherichia coli 83972 is a clinical asymptomatia bacteriuric isolate that is able to colonize the human urinary bladder without inducing an immune response. Here we demonstrate that one of the mechanisms by which this strain has become attenuated is through the mutation of its genes encoding type...

  2. Collagen-like proteins in pathogenic E. coli strains.

    Directory of Open Access Journals (Sweden)

    Neelanjana Ghosh

    Full Text Available The genome sequences of enterohaemorrhagic E. coli O157:H7 strains show multiple open-reading frames with collagen-like sequences that are absent from the common laboratory strain K-12. These putative collagens are included in prophages embedded in O157:H7 genomes. These prophages carry numerous genes related to strain virulence and have been shown to be inducible and capable of disseminating virulence factors by horizontal gene transfer. We have cloned two collagen-like proteins from E. coli O157:H7 into a laboratory strain and analysed the structure and conformation of the recombinant proteins and several of their constituting domains by a variety of spectroscopic, biophysical, and electron microscopy techniques. We show that these molecules exhibit many of the characteristics of vertebrate collagens, including trimer formation and the presence of a collagen triple helical domain. They also contain a C-terminal trimerization domain, and a trimeric α-helical coiled-coil domain with an unusual amino acid sequence almost completely lacking leucine, valine or isoleucine residues. Intriguingly, these molecules show high thermal stability, with the collagen domain being more stable than those of vertebrate fibrillar collagens, which are much longer and post-translationally modified. Under the electron microscope, collagen-like proteins from E. coli O157:H7 show a dumbbell shape, with two globular domains joined by a hinged stalk. This morphology is consistent with their likely role as trimeric phage side-tail proteins that participate in the attachment of phage particles to E. coli target cells, either directly or through assembly with other phage tail proteins. Thus, collagen-like proteins in enterohaemorrhagic E. coli genomes may have a direct role in the dissemination of virulence-related genes through infection of harmless strains by induced bacteriophages.

  3. Uropathogenic Escherichia coli (UPEC) strains may carry virulence properties of diarrhoeagenic E. coli.

    Science.gov (United States)

    Abe, Cecilia M; Salvador, Fábia A; Falsetti, Ivan N; Vieira, Mônica A M; Blanco, Jorge; Blanco, Jesús E; Blanco, Miguel; Machado, Antônia M O; Elias, Waldir P; Hernandes, Rodrigo T; Gomes, Tânia A T

    2008-04-01

    To analyze whether Escherichia coli strains that cause urinary tract infections (UPEC) share virulence characteristics with the diarrheagenic E. coli (DEC) pathotypes and to recognize their genetic diversity, 225 UPEC strains were examined for the presence of various properties of DEC and UPEC (type of interaction with HeLa cells, serogroups and presence of 30 virulence genes). No correlation between adherence patterns and serogroups was observed. Forty-five serogroups were found, but 64% of the strains belonged to one of the 12 serogroups (O1, O2, O4, O6, O7, O14, O15, O18, O21, O25, O75, and O175) and carried UPEC virulence genes (pap, hly, aer, sfa, cnf). The DEC genes found were: aap, aatA, aggC, agg3C, aggR, astA, eae, ehly, iha, irp2, lpfA(O113), pet, pic, pilS, and shf. Sixteen strains presented aggregative adherence and/or the aatA sequence, which are characteristics of enteroaggregative E. coli (EAEC), one of the DEC pathotypes. In summary, certain UPEC strains may carry DEC virulence properties, mostly associated to the EAEC pathotype. This finding raises the possibility that at least some faecal EAEC strains might represent potential uropathogens. Alternatively, certain UPEC strains may have acquired EAEC properties, becoming a potential cause of diarrhoea.

  4. Impact of diversity of colonizing strains on strategies for sampling Escherichia coli from fecal specimens.

    Science.gov (United States)

    Lautenbach, Ebbing; Bilker, Warren B; Tolomeo, Pam; Maslow, Joel N

    2008-09-01

    Of 49 subjects, 21 were colonized with more than one strain of Escherichia coli and 12 subjects had at least one strain present in fewer than 20% of colonies. The ability to accurately characterize E. coli strain diversity is directly related to the number of colonies sampled and the underlying prevalence of the strain.

  5. 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.

  6. Alkaloids Modulate Motility, Biofilm Formation and Antibiotic Susceptibility of Uropathogenic Escherichia coli

    Science.gov (United States)

    Dusane, Devendra H.; Hosseinidoust, Zeinab; Asadishad, Bahareh; Tufenkji, Nathalie

    2014-01-01

    Alkaloid-containing natural compounds have shown promise in the treatment of microbial infections. However, practical application of many of these compounds is pending a mechanistic understanding of their mode of action. We investigated the effect of two alkaloids, piperine (found in black pepper) and reserpine (found in Indian snakeroot), on the ability of the uropathogenic bacterium Escherichia coli CFT073 to colonize abiotic surfaces. Sub-inhibitory concentrations of both compounds (0.5 to 10 µg/mL) decreased bacterial swarming and swimming motilities and increased biofilm formation. qRT-PCR revealed a decrease in the expression of the flagellar gene (fliC) and motility genes (motA and motB) along with an increased expression of adhesin genes (fimA, papA, uvrY). Interestingly, piperine increased penetration of the antibiotics ciprofloxacin and azithromycin into E. coli CFT073 biofilms and consequently enhanced the ability of these antibiotics to disperse pre-established biofilms. The findings suggest that these alkaloids can potentially affect bacterial colonization by hampering bacterial motility and may aid in the treatment of infection by increasing antibiotic penetration in biofilms. PMID:25391152

  7. Alkaloids modulate motility, biofilm formation and antibiotic susceptibility of uropathogenic Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Devendra H Dusane

    Full Text Available Alkaloid-containing natural compounds have shown promise in the treatment of microbial infections. However, practical application of many of these compounds is pending a mechanistic understanding of their mode of action. We investigated the effect of two alkaloids, piperine (found in black pepper and reserpine (found in Indian snakeroot, on the ability of the uropathogenic bacterium Escherichia coli CFT073 to colonize abiotic surfaces. Sub-inhibitory concentrations of both compounds (0.5 to 10 µg/mL decreased bacterial swarming and swimming motilities and increased biofilm formation. qRT-PCR revealed a decrease in the expression of the flagellar gene (fliC and motility genes (motA and motB along with an increased expression of adhesin genes (fimA, papA, uvrY. Interestingly, piperine increased penetration of the antibiotics ciprofloxacin and azithromycin into E. coli CFT073 biofilms and consequently enhanced the ability of these antibiotics to disperse pre-established biofilms. The findings suggest that these alkaloids can potentially affect bacterial colonization by hampering bacterial motility and may aid in the treatment of infection by increasing antibiotic penetration in biofilms.

  8. [Antimicrobial sensitivity of Escherichia coli strains with K1 antigen isolated from pregnant women and newborns].

    Science.gov (United States)

    Kaczmarek, Agnieszka; Budzyńska, Anna; Gospodarek, Eugenia

    2011-01-01

    The aim of this study was comparison of the susceptibility to antibiotics of E. coli strains with K1 antigen (E. coli K1+) and non-K1 E. coli strains (E. coli K1-). This study included 67 of E. coli K1+ and 67 of E. coli K1- strains isolated in the time period from June to September of 2008 from pregnant women and newborns hospitalized at dr. J. Biziel University Hospital number 2 L. Rydygier Collegium Medicum in Bydgoszcz Nicolaus Copernicus University in Toruń. Antimicrobial susceptibility of E. coli strains was tested by the disc-diffusion method, on the Mueller Hinton 2 Agar (Becton Dickinson). It was found that 64,2% of E. coli K1+ strains and 53,7% of E. coli K1-strains were susceptible to all tested antibiotics and chemioterapeutics. E. coli K1- strains were more often than E. coli K1+ nonsusceptible to at least one antimicrobial agent. The obtained results indicate that E. coli K1+ strains significant differed in the susceptibility to ampicillin/sulbactam (85,1% versus 95,5%) (p=0,041), cephalothin (70,1% versus 85,1%) (p=0,038) and tetracycline (91,0% versus 74,6%) (p=0,012) from E. coli K1-strains. All tested E. coli K1+ and K1-strains were sensitive to piperacillin/tazobactam, cefoperazone/sulbactam, cefotaxime, ceftazidime, cefepime, imipenem, amikacin, netilmicin and tigecycline. There weren't the ESBL-producing strains among tested E. coli K1+ and K1- rods.

  9. Molecular characterization of some new E. coli strains theoretically responsible for both intestinal and extraintestinal infections

    OpenAIRE

    Ghaleb Adwan; Kamel Adwan; Hiba Bourinee

    2016-01-01

    Strains of E. coli are divided into 3 major groups; commensal strains, diarrheagenic (intestinal) E. coli pathotypes and extraintestinal pathogenic E. coli. Extraintestinal pathogenic E. coli are unlike diarrheagenic pathotypes, they have not ability to cause intestinal disease in human, but they have normal ability for long-term colonization in the gut. This study aimed to spotlight on that intestinal and extraintestinal infections are not restricted to intestinal pathotypes and ...

  10. Origins of the E. coli Strain Causing an Outbreak of Hemolytic–Uremic Syndrome in Germany

    Science.gov (United States)

    Rasko, David A.; Webster, Dale R.; Sahl, Jason W.; Bashir, Ali; Boisen, Nadia; Scheutz, Flemming; Paxinos, Ellen E.; Sebra, Robert; Chin, Chen-Shan; Iliopoulos, Dimitris; Klammer, Aaron; Peluso, Paul; Lee, Lawrence; Kislyuk, Andrey O.; Bullard, James; Kasarskis, Andrew; Wang, Susanna; Eid, John; Rank, David; Redman, Julia C.; Steyert, Susan R.; Frimodt-Møller, Jakob; Struve, Carsten; Petersen, Andreas M.; Krogfelt, Karen A.; Nataro, James P.; Schadt, Eric E.; Waldor, Matthew K.

    2011-01-01

    BACKGROUND A large outbreak of diarrhea and the hemolytic–uremic syndrome caused by an unusual serotype of Shiga-toxin–producing Escherichia coli (O104:H4) began in Germany in May 2011. As of July 22, a large number of cases of diarrhea caused by Shiga-toxin–producing E. coli have been reported — 3167 without the hemolytic–uremic syndrome (16 deaths) and 908 with the hemolytic–uremic syndrome (34 deaths) — indicating that this strain is notably more virulent than most of the Shiga-toxin–producing E. coli strains. Preliminary genetic characterization of the outbreak strain suggested that, unlike most of these strains, it should be classified within the enteroaggregative pathotype of E. coli. METHODS We used third-generation, single-molecule, real-time DNA sequencing to determine the complete genome sequence of the German outbreak strain, as well as the genome sequences of seven diarrhea-associated enteroaggregative E. coli serotype O104:H4 strains from Africa and four enteroaggregative E. coli reference strains belonging to other serotypes. Genomewide comparisons were performed with the use of these enteroaggregative E. coli genomes, as well as those of 40 previously sequenced E. coli isolates. RESULTS The enteroaggregative E. coli O104:H4 strains are closely related and form a distinct clade among E. coli and enteroaggregative E. coli strains. However, the genome of the German outbreak strain can be distinguished from those of other O104:H4 strains because it contains a prophage encoding Shiga toxin 2 and a distinct set of additional virulence and antibiotic-resistance factors. CONCLUSIONS Our findings suggest that horizontal genetic exchange allowed for the emergence of the highly virulent Shiga-toxin–producing enteroaggregative E. coli O104:H4 strain that caused the German outbreak. More broadly, these findings highlight the way in which the plasticity of bacterial genomes facilitates the emergence of new pathogens. PMID:21793740

  11. Binding of collagens to an enterotoxigenic strain of Escherichia coli

    Energy Technology Data Exchange (ETDEWEB)

    Visai, L.; Speziale, P.; Bozzini, S. (Univ. of Pavia (Italy))

    1990-02-01

    An enterotoxigenic strain of Escherichia coli, B34289c, has been shown to bind the N-terminal region of fibronectin with high affinity. We now report that this strain also binds collagen. The binding of 125I-labeled type II collagen to bacteria was time dependent and reversible. Bacteria expressed a limited number of collagen receptors (2.2 x 10(4) per cell) and bound collagen with a Kd of 20 nM. All collagen types tested (I to V) as well as all tested cyanogen bromide-generated peptides (alpha 1(I)CB2, alpha 1(I)CB3, alpha 1(I)CB7, alpha 1(I)CB8, and alpha 2(I)CB4) were recognized by bacterial receptors, as demonstrated by the ability of these proteins to inhibit the binding of 125I-labeled collagen to bacteria. Of several unlabeled proteins tested in competition experiments, fibronectin and its N-terminal region strongly inhibited binding of the radiolabeled collagen to E. coli cells. Conversely, collagen competed with an 125I-labeled 28-kilodalton fibronectin fragment for bacterial binding. Collagen bound to bacteria could be displaced by excess amounts of either unlabeled fibronectin or its N-terminal fragment. Similarly, collagen could displace 125I-labeled N-terminal peptide of fibronectin bound to the bacterial cell surface. Bacteria grown at 41 degrees C or in the presence of glucose did not express collagen or fibronectin receptors. These results indicate the presence of specific binding sites for collagen on the surface of E. coli cells and furthermore that the collagen and fibronectin binding sites are located in close proximity, possibly on the same structure.

  12. Subinhibitory Concentrations of Allicin Decrease Uropathogenic Escherichia coli (UPEC) Biofilm Formation, Adhesion Ability, and Swimming Motility.

    Science.gov (United States)

    Yang, Xiaolong; Sha, Kaihui; Xu, Guangya; Tian, Hanwen; Wang, Xiaoying; Chen, Shanze; Wang, Yi; Li, Jingyu; Chen, Junli; Huang, Ning

    2016-06-29

    Uropathogenic Escherichia coli (UPEC) biofilm formation enables the organism to avoid the host immune system, resist antibiotics, and provide a reservoir for persistent infection. Once the biofilm is established, eradication of the infection becomes difficult. Therefore, strategies against UPEC biofilm are urgently required. In this study, we investigated the effect of allicin, isolated from garlic essential oil, on UPEC CFT073 and J96 biofilm formation and dispersal, along with its effect on UPEC adhesion ability and swimming motility. Sub-inhibitory concentrations (sub-MICs) of allicin decreased UPEC biofilm formation and affected its architecture. Allicin was also capable of dispersing biofilm. Furthermore, allicin decreased the bacterial adhesion ability and swimming motility, which are important for biofilm formation. Real-time quantitative polymerase chain reaction (RT-qPCR) revealed that allicin decreased the expression of UPEC type 1 fimbriae adhesin gene fimH. Docking studies suggested that allicin was located within the binding pocket of heptyl α-d-mannopyrannoside in FimH and formed hydrogen bonds with Phe1 and Asn135. In addition, allicin decreased the expression of the two-component regulatory systems (TCSs) cognate response regulator gene uvrY and increased the expression of the RNA binding global regulatory protein gene csrA of UPEC CFT073, which is associated with UPEC biofilm. The findings suggest that sub-MICs of allicin are capable of affecting UPEC biofilm formation and dispersal, and decreasing UPEC adhesion ability and swimming motility.

  13. Subinhibitory Concentrations of Allicin Decrease Uropathogenic Escherichia coli (UPEC Biofilm Formation, Adhesion Ability, and Swimming Motility

    Directory of Open Access Journals (Sweden)

    Xiaolong Yang

    2016-06-01

    Full Text Available Uropathogenic Escherichia coli (UPEC biofilm formation enables the organism to avoid the host immune system, resist antibiotics, and provide a reservoir for persistent infection. Once the biofilm is established, eradication of the infection becomes difficult. Therefore, strategies against UPEC biofilm are urgently required. In this study, we investigated the effect of allicin, isolated from garlic essential oil, on UPEC CFT073 and J96 biofilm formation and dispersal, along with its effect on UPEC adhesion ability and swimming motility. Sub-inhibitory concentrations (sub-MICs of allicin decreased UPEC biofilm formation and affected its architecture. Allicin was also capable of dispersing biofilm. Furthermore, allicin decreased the bacterial adhesion ability and swimming motility, which are important for biofilm formation. Real-time quantitative polymerase chain reaction (RT-qPCR revealed that allicin decreased the expression of UPEC type 1 fimbriae adhesin gene fimH. Docking studies suggested that allicin was located within the binding pocket of heptyl α-d-mannopyrannoside in FimH and formed hydrogen bonds with Phe1 and Asn135. In addition, allicin decreased the expression of the two-component regulatory systems (TCSs cognate response regulator gene uvrY and increased the expression of the RNA binding global regulatory protein gene csrA of UPEC CFT073, which is associated with UPEC biofilm. The findings suggest that sub-MICs of allicin are capable of affecting UPEC biofilm formation and dispersal, and decreasing UPEC adhesion ability and swimming motility.

  14. Complete Genome Sequence of the Escherichia coli PMV-1 Strain, a Model Extraintestinal Pathogenic E. coli Strain Used for Host-Pathogen Interaction Studies

    OpenAIRE

    Peris-Bondia, Francesc; Muraille, Eric; Van Melderen, Laurence

    2013-01-01

    Escherichia coli is a highly versatile species, causing diverse intestinal and extraintestinal infections. Here, we present the complete genome sequence of PMV-1, an O18:K1 extraintestinal pathogenic E.?coli (ExPEC) strain that is used as a model for peritonitis in mice and was useful for deciphering the innate immune response triggered by ExPEC infections.

  15. Comparison of whole genome sequences from human and non-human Escherichia coli O26 strains

    Science.gov (United States)

    Shiga toxin-producing Escherichia coli (STEC) O26 is the second leading E. coli serogroup responsible for human illness outbreaks behind E. coli O157:H7. Recent outbreaks have been linked to emerging pathogenic O26:H11 strains harboring stx2 only. Cattle have been recognized as an important reserv...

  16. Genome-Wide Discovery of Genes Required for Capsule Production by Uropathogenic Escherichia coli.

    Science.gov (United States)

    Goh, Kelvin G K; Phan, Minh-Duy; Forde, Brian M; Chong, Teik Min; Yin, Wai-Fong; Chan, Kok-Gan; Ulett, Glen C; Sweet, Matthew J; Beatson, Scott A; Schembri, Mark A

    2017-10-24

    Uropathogenic Escherichia coli (UPEC) is a major cause of urinary tract and bloodstream infections and possesses an array of virulence factors for colonization, survival, and persistence. One such factor is the polysaccharide K capsule. Among the different K capsule types, the K1 serotype is strongly associated with UPEC infection. In this study, we completely sequenced the K1 UPEC urosepsis strain PA45B and employed a novel combination of a lytic K1 capsule-specific phage, saturated Tn5 transposon mutagenesis, and high-throughput transposon-directed insertion site sequencing (TraDIS) to identify the complement of genes required for capsule production. Our analysis identified known genes involved in capsule biosynthesis, as well as two additional regulatory genes (mprA and lrhA) that we characterized at the molecular level. Mutation of mprA resulted in protection against K1 phage-mediated killing, a phenotype restored by complementation. We also identified a significantly increased unidirectional Tn5 insertion frequency upstream of the lrhA gene and showed that strong expression of LrhA induced by a constitutive Pcl promoter led to loss of capsule production. Further analysis revealed loss of MprA or overexpression of LrhA affected the transcription of capsule biosynthesis genes in PA45B and increased sensitivity to killing in whole blood. Similar phenotypes were also observed in UPEC strains UTI89 (K1) and CFT073 (K2), demonstrating that the effects were neither strain nor capsule type specific. Overall, this study defined the genome of a UPEC urosepsis isolate and identified and characterized two new regulatory factors that affect UPEC capsule production.IMPORTANCE Urinary tract infections (UTIs) are among the most common bacterial infections in humans and are primarily caused by uropathogenic Escherichia coli (UPEC). Many UPEC strains express a polysaccharide K capsule that provides protection against host innate immune factors and contributes to survival and

  17. Novel genes associated with enhanced motility of Escherichia coli ST131.

    Science.gov (United States)

    Kakkanat, Asha; Phan, Minh-Duy; Lo, Alvin W; Beatson, Scott A; Schembri, Mark A

    2017-01-01

    Uropathogenic Escherichia coli (UPEC) is the cause of ~75% of all urinary tract infections (UTIs) and is increasingly associated with multidrug resistance. This includes UPEC strains from the recently emerged and globally disseminated sequence type 131 (ST131), which is now the dominant fluoroquinolone-resistant UPEC clone worldwide. Most ST131 strains are motile and produce H4-type flagella. Here, we applied a combination of saturated Tn5 mutagenesis and transposon directed insertion site sequencing (TraDIS) as a high throughput genetic screen and identified 30 genes associated with enhanced motility of the reference ST131 strain EC958. This included 12 genes that repress motility of E. coli K-12, four of which (lrhA, ihfA, ydiV, lrp) were confirmed in EC958. Other genes represented novel factors that impact motility, and we focused our investigation on characterisation of the mprA, hemK and yjeA genes. Mutation of each of these genes in EC958 led to increased transcription of flagellar genes (flhD and fliC), increased expression of the FliC flagellin, enhanced flagella synthesis and a hyper-motile phenotype. Complementation restored all of these properties to wild-type level. We also identified Tn5 insertions in several intergenic regions (IGRs) on the EC958 chromosome that were associated with enhanced motility; this included flhDC and EC958_1546. In both of these cases, the Tn5 insertions were associated with increased transcription of the downstream gene(s), which resulted in enhanced motility. The EC958_1546 gene encodes a phage protein with similarity to esterase/deacetylase enzymes involved in the hydrolysis of sialic acid derivatives found in human mucus. We showed that over-expression of EC958_1546 led to enhanced motility of EC958 as well as the UPEC strains CFT073 and UTI89, demonstrating its activity affects the motility of different UPEC strains. Overall, this study has identified and characterised a number of novel factors associated with enhanced

  18. Strain level differences in E. coli transport, cell surface and adhesion characteristics

    Science.gov (United States)

    Given the importance of E. coli as an indicator of fecal contamination, it is imperative that genotypic and phenotypic variability among strains of E. coli from the same host and/or environmental niche are understood. The goal of this study was to evaluate the effect of strain level differences on t...

  19. Strain level differences in Escherichia coli transport, cell surface and adhesion characteristics

    Science.gov (United States)

    Given the importance of Escherichia coli as both an indicator of fecal contamination and a potential pathogen, it is imperative that genotypic and phenotypic variability among strains of E. coli from the same host and/or environmental niche are understood. Strain survival and variation are regulated...

  20. Molecular characterization of diarrheagenic Escherichia coli strains from stools samples and food products in Colombia

    Science.gov (United States)

    Rúgeles, Laura Cristina; Bai, Jing; Martínez, Aída Juliana; Vanegas, María Consuelo; Gómez-Duarte, Oscar Gilberto

    2010-01-01

    The prevalence of diarrheagenic E. coli in childhood diarrhea and the role of contaminated food products in disease transmission in Colombia are largely unknown. The aim of this study is to identify E. coli pathotypes, including E. coli O157:H7, from 108 stool samples from children with acute diarrhea, 38 meat samples and 38 vegetable samples. Multiplex PCR and Bax Dupont systems were used for E. coli pathotype detection. Eighteen (9.8%) E. coli diarrheagenic pathotypes were detected among all clinical and food product samples tested. Four different pathotypes were identified from clinical samples, including enteroaggregative E. coli, enterotoxigenic E. coli, shiga-toxin producing E. coli, and enteropathogenic E. coli. Food product samples were positive for enteroaggregative and shiga-toxin producing E. coli, suggesting that meat and vegetables may be involved in transmission of these E. coli pathotypes in the community. Most E. coli strains identified belong to the phylogenetic groups A and B1, known to be associated with intestinal rather than extraintestinal E. coli clones. Our data is the first molecular E. coli report that confirms the presence of E. coli pathotypes circulating in Colombia among children with diarrhea and food products for human consumption. Implementation of multiplex PCR technology in Latin America and other countries with limited resources may provide an important epidemiological tool for the surveillance of E. coli pathotypes from clinical isolates as well as from water and food product samples. PMID:20153069

  1. Molecular characterization of some new E. coli strains theoretically responsible for both intestinal and extraintestinal infections

    Directory of Open Access Journals (Sweden)

    Ghaleb Adwan

    2016-06-01

    Full Text Available Strains of E. coli are divided into 3 major groups; commensal strains, diarrheagenic (intestinal E. coli pathotypes and extraintestinal pathogenic E. coli. Extraintestinal pathogenic E. coli are unlike diarrheagenic pathotypes, they have not ability to cause intestinal disease in human, but they have normal ability for long-term colonization in the gut. This study aimed to spotlight on that intestinal and extraintestinal infections are not restricted to intestinal pathotypes and extraintestinal pathogenic E. coli, respectively. A total of 102 uropathogenic E. coli isolates were collected during 2012 and 2015. A multiplex PCR was used to detect phylogenetic groups, virulence factors for extraintestinal pathogenic E. coli and intestinal E. coli pathotypes genes. Results of this research showed that 12 (11.8% uropathogenic E. coli isolates had genes that are theoretically responsible for intestinal diseases, were 10 of these isolates belonged to phylogentic group D and 2 isolates to phylogentic group A. We conclude from these results, this is the first report on the molecular characterization of E. coli that theoretically can cause both intestinal and extraintestinal infections simultaneously. The presence of these strains has a great impact on public health. More studies are necessary before definitive conclusions if these strains are a different clone that theoretically have ability to cause both intestinal and extraintestinal infections and belonged to phylogenetic groups other than A and D. Products of diarrheagenic genes in UPEC strains need further studies to detect their effects in intestinal infections

  2. Peptidoglycan Association of Murein Lipoprotein Is Required for KpsD-Dependent Group 2 Capsular Polysaccharide Expression and Serum Resistance in a Uropathogenic Escherichia coli Isolate.

    Science.gov (United States)

    Diao, Jingyu; Bouwman, Catrien; Yan, Donghong; Kang, Jing; Katakam, Anand K; Liu, Peter; Pantua, Homer; Abbas, Alexander R; Nickerson, Nicholas N; Austin, Cary; Reichelt, Mike; Sandoval, Wendy; Xu, Min; Whitfield, Chris; Kapadia, Sharookh B

    2017-05-23

    Murein lipoprotein (Lpp) and peptidoglycan-associated lipoprotein (Pal) are major outer membrane lipoproteins in Escherichia coli Their roles in cell-envelope integrity have been documented in E. coli laboratory strains, and while Lpp has been linked to serum resistance in vitro, the underlying mechanism has not been established. Here, lpp and pal mutants of uropathogenic E. coli strain CFT073 showed reduced survival in a mouse bacteremia model, but only the lpp mutant was sensitive to serum killing in vitro The peptidoglycan-bound Lpp form was specifically required for preventing complement-mediated bacterial lysis in vitro and complement-mediated clearance in vivo Compared to the wild-type strain, the lpp mutant had impaired K2 capsular polysaccharide production and was unable to respond to exposure to serum by elevating capsular polysaccharide amounts. These properties correlated with altered cellular distribution of KpsD, the predicted outer membrane translocon for "group 2" capsular polysaccharides. We identified a novel Lpp-dependent association between functional KpsD and peptidoglycan, highlighting important interplay between cell envelope components required for resistance to complement-mediated lysis in uropathogenic E. coli isolates.IMPORTANCE Uropathogenic E. coli (UPEC) isolates represent a significant cause of nosocomial urinary tract and bloodstream infections. Many UPEC isolates are resistant to serum killing. Here, we show that a major cell-envelope lipoprotein (murein lipoprotein) is required for serum resistance in vitro and for complement-mediated bacterial clearance in vivo This is mediated, in part, through a novel mechanism by which murein lipoprotein affects the proper assembly of a key component of the machinery involved in production of "group 2" capsules. The absence of murein lipoprotein results in impaired production of the capsule layer, a known participant in complement resistance. These results demonstrate an important role for

  3. Uropathogenic Escherichia coli P and Type 1 fimbriae act in synergy in a living host to facilitate renal colonization leading to nephron obstruction.

    Directory of Open Access Journals (Sweden)

    Keira Melican

    2011-02-01

    Full Text Available The progression of a natural bacterial infection is a dynamic process influenced by the physiological characteristics of the target organ. Recent developments in live animal imaging allow for the study of the dynamic microbe-host interplay in real-time as the infection progresses within an organ of a live host. Here we used multiphoton microscopy-based live animal imaging, combined with advanced surgical procedures, to investigate the role of uropathogenic Escherichia coli (UPEC attachment organelles P and Type 1 fimbriae in renal bacterial infection. A GFP+ expressing variant of UPEC strain CFT073 and genetically well-defined isogenic mutants were microinfused into rat glomerulus or proximal tubules. Within 2 h bacteria colonized along the flat squamous epithelium of the Bowman's capsule despite being exposed to the primary filtrate. When facing the challenge of the filtrate flow in the proximal tubule, the P and Type 1 fimbriae appeared to act in synergy to promote colonization. P fimbriae enhanced early colonization of the tubular epithelium, while Type 1 fimbriae mediated colonization of the center of the tubule via a mechanism believed to involve inter-bacterial binding and biofilm formation. The heterogeneous bacterial community within the tubule subsequently affected renal filtration leading to total obstruction of the nephron within 8 h. Our results reveal the importance of physiological factors such as filtration in determining bacterial colonization patterns, and demonstrate that the spatial resolution of an infectious niche can be as small as the center, or periphery, of a tubule lumen. Furthermore, our data show how secondary physiological injuries such as obstruction contribute to the full pathophysiology of pyelonephritis.

  4. Phenotypic and genotypic characterisation of Escherichia coli strains serogrouped as enteropathogenic E. coli (EPEC) isolated from pasteurised milk.

    Science.gov (United States)

    Carneiro, L A M; Lins, M C; Garcia, F R A; Silva, A P S; Mauller, P M; Alves, G B; Rosa, A C P; Andrade, J R C; Freitas-Almeida, A C; Queiroz, M L P

    2006-04-15

    Fifty-six Escherichia coli strains, serogrouped as EPEC, isolated from three different brands of pasteurised milk commercialised in Rio de Janeiro, Brazil, were tested for enteropathogenicity markers. Most of the strains (71.4%) were adherent to HEp-2 cells. The adherent strains were distributed among 7 EPEC serogroups (O26, O55, O111, O114, O125, O127, O128, O158). Although almost half of these strains (33.9%) presented unrecognisable adherence phenotypes, classical adherence patterns (localised-like, aggregative and diffuse adherence) described for E. coli and epidemiologically associated with diarrheagenic strains were observed. None of the strains showed typical localised adherence, usually associated with EPEC strains, but 4 of them displayed a localised-like adherence (LAL) phenotype, characterised by fewer and less compact microcolonies but that is still associated with diarrheagenic strains as well as strains of non-human origin. Indeed, 3 of these 4 strains were able to elicit the attaching-effacing lesion (FAS-positive), the central feature of EPEC pathogenesis, and hybridised with bfpA and eae DNA probes. The other LAL-positive strain hybridised with the bfpA probe but gave negative results for the eae probe and FAS assays. Interestingly, all LAL-positive strains produced amplicons of 200 bp in the PCR for bfpA, instead of the expected 326 bp fragment. PCR reactions for stx1 and stx2, two shiga-toxin-encoding genes, gave negative results. Typing of LEE-associated genes by PCR showed the profile eae (beta), tir (beta), espA (alpha) and espB (alpha) for one of the LAL-positive strain. The most prevalent adherence phenotype was the aggregative pattern which is observed in strains epidemiologically associated with persistent diarrhea. Additionally, one strain promoted complete detachment of the Hep-2 cell monolayer after 3 h of infection which might be related to the production of citotoxins, a feature that has been increasingly observed in clinical strains

  5. Molecular and Phenotypic Characterization of Diarrheagenic Escherichia coli Strains Isolated from Bacteremic Children.

    Science.gov (United States)

    Riveros, Maribel; García, Wilfredo; García, Coralith; Durand, David; Mercado, Erik; Ruiz, Joaquim; Ochoa, Theresa J

    2017-11-01

    Escherichia coli is an important cause of Gram-negative bacteremia. The aim of this study was to characterize at the molecular and phenotypic levels E. coli strains belonging to different diarrheagenic pathotypes [diarrheagenic E. coli (DEC)] isolated from bacteremia in children younger than 5 years of age. Seventy bacteremia E. coli strains were collected in a prospective study in 12 hospitals in Lima, Peru. The presence of virulence genes associated with DEC [enterotoxigenic (lt and st), enteropathogenic (eaeA), shiga toxin-producing (stx1and stx2), enteroinvasive (ipaH), enteroaggregative (aggR), and diffusely adherent (daaD)] was determined by multiplex real-time polymerase chain reaction (PCR). Those positive E. coli strains were further analyzed for 18 additional virulence factors encoding genes and others phenotypic features. Virulence genes associated with DEC were identified in seven bacteremic children (10%), including: one aggR-positive [enteroaggregative E. coli (EAEC)], one eaeA-positive [enteropathogenic E. coli (EPEC)], one st-positive [enterotoxigenic E. coli (ETEC)], one daaD-positive [diffusely adherent E. coli (DAEC)], and three strain positive for aggR and daaD (EAEC/DAEC) at the same time. All strains, except EPEC, had the Ag43 adhesin, and all, except ETEC had the siderophore gene fyuA. The phylogenetic profile of these strains was variable, two (B2), two (D), two (A), and one (B1) strain. These isolates were susceptible to all tested antibacterial agents except to ampicillin and gentamicin. The three EAEC/DAEC strains showed biofilm formation and aggregative adhesion and had the same repetitive extragenic palindromic-PCR patterns. These findings suggest that some DEC strains, especially agg-R and daa-D positive, might cause bacteremia in children.

  6. Escherichia coli identification and strain discrimination using nanosecond laser-induced breakdown spectroscopy

    Science.gov (United States)

    Rehse, Steven; Diedrich, Jonathan; Palchaudhuri, Sunil

    2007-06-01

    Three strains of Escherichia coli, one strain of black mold and one strain of Candida albicans yeast have been analyzed by laser-induced breakdown spectroscopy (LIBS) using nanosecond laser pulses. All microorganisms were analyzed while still alive and with no sample preparation. Nineteen atomic and ionic emission lines have been identified in the spectrum, which is dominated by calcium, magnesium and sodium. A discriminant function analysis (DFA) has been used to discriminate between the bio-types and E. coli strains. This is the first demonstration of the ability of the LIBS technique to differentiate between different strains of a single species.

  7. A genomically modified Escherichia coli strain carrying an orthogonal E. coli histidyl-tRNA synthetase•tRNAHispair.

    Science.gov (United States)

    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.

  8. Expression of ornithine decarboxylase of Coccidioides immitis in three Escherichia coli strains carrying the lambda DE3 lysogen and an E. coli EWH319 strain odc- null mutant.

    Science.gov (United States)

    Pantoja-Hernández, Miguel Angel; Muñoz-Sánchez, Claudia Ivonne; Guevara-González, Ramón Gerardo; Botello-Alvarez, Enrique; González-Chavira, Mario Martín; Torres-Pacheco, Irineo; Guevara-Olvera, Lorenzo

    2004-01-01

    Ornithine decarboxylase from respiratory fungal pathogen, Coccidioides immitis, cloned in the pETCiODC plasmid under control of T7lac promoter, was produced in E. coli BL21(DE3), BL21(DE3)pLysS, BLR(DE3) and EWH319 transformant strains. E. coli BL21(DE3)pLysS-pETCiODC expressed the highest specific activity of ODC, suggesting that this strain could be successfully used for protein structure and drug testing studies.

  9. Origins of the E. coli strain causing an outbreak of hemolytic-uremic syndrome in Germany

    DEFF Research Database (Denmark)

    Rasko, David A; Webster, Dale R; Sahl, Jason W

    2011-01-01

    A large outbreak of diarrhea and the hemolytic-uremic syndrome caused by an unusual serotype of Shiga-toxin-producing Escherichia coli (O104:H4) began in Germany in May 2011. As of July 22, a large number of cases of diarrhea caused by Shiga-toxin-producing E. coli have been reported--3167 without...... the hemolytic-uremic syndrome (16 deaths) and 908 with the hemolytic-uremic syndrome (34 deaths)--indicating that this strain is notably more virulent than most of the Shiga-toxin-producing E. coli strains. Preliminary genetic characterization of the outbreak strain suggested that, unlike most of these strains......, it should be classified within the enteroaggregative pathotype of E. coli....

  10. Identification of R plasmids mediating gentamicin resistance from Escherichia coli strains in Japan.

    OpenAIRE

    Ike, Y; Fujisawa-Kon, N; Shimizu, S; Motohashi, K; Hashimoto, H; Mitsuhashi, S

    1981-01-01

    Eight gentamicin-resistant Escherichia coli were identified from among 630 E. coli strans isolated from parenteral infections. All eight strains were multiply resistant and harbored R plasmids mediating gentamicin resistance. The R plasmids specified the formation of two types of aminoglycoside-inactivating enzymes AAD (2") and APH (3').

  11. Complete genome sequence of the avian pathogenic Escherichia coli strain APEC O78.

    Science.gov (United States)

    Mangiamele, Paul; Nicholson, Bryon; Wannemuehler, Yvonne; Seemann, Torsten; Logue, Catherine M; Li, Ganwu; Tivendale, Kelly A; Nolan, Lisa K

    2013-03-21

    Colibacillosis, caused by avian pathogenic Escherichia coli (APEC), is a significant disease, causing extensive animal and financial losses globally. Because of the significance of this disease, more knowledge is needed regarding APEC's mechanisms of virulence. Here, we present the fully closed genome sequence of a typical avian pathogenic E. coli strain belonging to the serogroup O78.

  12. Isolation of Escherichia coli 0157:H7 Strain from Fecal Samples of Zoo Animal

    Directory of Open Access Journals (Sweden)

    Aseel Mohammed Hamzah

    2013-01-01

    Full Text Available The isolation and characterization of Escherichia coli O157:H7 strains from 22 out of 174 fecal samples from petting zoo animals representing twenty-two different species (camel, lion, goats, zebra, bear, baboon monkey, Siberian monkey, deer, elk, llama, pony, horses, fox, kangaroo, wolf, porcupine, chickens, tiger, ostrich, hyena, dogs, and wildcats were investigated. One petting Al-Zawraa zoological society of Baghdad was investigated for E. coli O157:H7 over a 16-month period that spanned two summer and two autumn seasons. Variation in the occurrence of E. coli O157:H7-positive petting zoo animals was observed, with animals being culture positive only in the summer months but not in the spring, autumn, or winter. E. coli O157:H7 isolates were distinguished by agglutination with E. coli O157:H7 latex reagent (Oxoid, identified among the isolates, which showed that multiple E. coli strains were isolated from one petting zoo animal, in which a single animal simultaneously shed multiple E. coli strains; E. coli O157:H7 was isolated only by selective enrichment culture of 2 g of petting zoo animal feces. In contrast, strains other than O157:H7 were cultured from feces of petting zoo animals without enrichment.

  13. Molecular typing of uropathogenic E. coli strains by the ERIC-PCR method.

    Science.gov (United States)

    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.

  14. IncH plasmids in Escherichia coli strains isolated from broiler chicken carcasses.

    OpenAIRE

    Chaslus-Dancla, E; Lafont, J P

    1985-01-01

    Plasmids conferring tellurite resistance were transferred at low temperature (27 degrees C) from Escherichia coli strains isolated from chicken carcasses at the time of slaughter and after storage. They belonged to group IncH, as evidenced by their large molecular weight and incompatibility with plasmid pIP233. E. coli strains contaminating chickens meat can thus represent a source of IncH plasmids in the food chain of humans.

  15. Development of a multiplex PCR assay for detection of Shiga toxin-producing Escherichia coli, enterohemorrhagic E. coli, and enteropathogenic E. coli strains.

    Science.gov (United States)

    Botkin, Douglas J; Galli, Lucía; Sankarapani, Vinoth; Soler, Michael; Rivas, Marta; Torres, Alfredo G

    2012-01-01

    Escherichia coli O157:H7 and other pathogenic E. coli strains are enteric pathogens associated with food safety threats and which remain a significant cause of morbidity and mortality worldwide. In the current study, we investigated whether enterohemorrhagic E. coli (EHEC), Shiga toxin-producing E. coli (STEC), and enteropathogenic E. coli (EPEC) strains can be rapidly and specifically differentiated with multiplex PCR (mPCR) utilizing selected biomarkers associated with each strain's respective virulence genotype. Primers were designed to amplify multiple intimin (eae) and long polar fimbriae (lpfA) variants, the bundle-forming pilus gene bfpA, and the Shiga toxin-encoding genes stx1 and stx2. We demonstrated consistent amplification of genes specific to the prototype EHEC O157:H7 EDL933 (lpfA1-3, lpfA2-2, stx1, stx2, and eae-γ) and EPEC O127:H6 E2348/69 (eae-α, lpfA1-1, and bfpA) strains using the optimized mPCR protocol with purified genomic DNA (gDNA). A screen of gDNA from isolates in a diarrheagenic E. coli collection revealed that the mPCR assay was successful in predicting the correct pathotype of EPEC and EHEC clones grouped in the distinctive phylogenetic disease clusters EPEC1 and EHEC1, and was able to differentiate EHEC1 from EHEC2 clusters. The assay detection threshold was 2 × 10(4) CFU per PCR reaction for EHEC and EPEC. mPCR was also used to screen Argentinean clinical samples from hemolytic uremic syndrome and diarrheal patients, resulting in 91% sensitivity and 84% specificity when compared to established molecular diagnostic procedures. In conclusion, our mPCR methodology permitted differentiation of EPEC, STEC and EHEC strains from other pathogenic E. coli; therefore, the assay becomes an additional tool for rapid diagnosis of these organisms.

  16. Prevalence of Antibiotic-Resistant Strains of Escherichia coli in ...

    African Journals Online (AJOL)

    A measured Escherichia coli level in drinking water is perhaps the most popular means of determining human health risks globally. Water samples from wells, boreholes and sachet water, the 3 predominant sources of drinking water in the study area were evaluated for the presence of bacteria, particularly E coli. Bacteria ...

  17. Natural transformation-mediated transfer of erythromycin resistance in Campylobacter coli strains from turkeys and swine.

    Science.gov (United States)

    Kim, Joo-Sung; Carver, Donna K; Kathariou, Sophia

    2006-02-01

    Erythromycin resistance in Campylobacter coli from meat animals is frequently encountered and could represent a substantial barrier to antibiotic treatment of human infections. Erythromycin resistance in this organism has been associated with a point mutation (A2075G) in the 23S rRNA gene. However, the mechanisms responsible for possible dissemination of erythromycin resistance in C. coli remain poorly understood. In this study, we investigated transformation-mediated acquisition of erythromycin resistance by genotypically diverse C. coli strains from turkeys and swine, with total genomic DNA from erythromycin-resistant C. coli of either turkey or swine origin used as a donor. Overall, transformation to erythromycin resistance was significantly more frequent in C. coli strains from turkeys than in swine-derived strains (P transformation to erythromycin resistance was 10(-5) to 10(-6) for turkey-derived strains but 10(-7) or less for C. coli from swine. Transformants harbored the point mutation A2075G in the 23S rRNA gene, as did the erythromycin-resistant strains used as DNA donors. Erythromycin resistance was stable in transformants following serial transfers in the absence of the antibiotic, and most transformants had high MICs (>256 microg/ml), as did the C. coli donor strains. In contrast to the results obtained with transformation, spontaneous mutants had relatively low erythromycin MICs (32 to 64 microg/ml) and lacked the A2075G mutation in the 23S rRNA gene. These findings suggest that natural transformation has the potential to contribute to the dissemination of high-level resistance to erythromycin among C. coli strains colonizing meat animals.

  18. Strain-Level Discrimination of Shiga Toxin-Producing Escherichia coli in Spinach Using Metagenomic Sequencing.

    Science.gov (United States)

    Leonard, Susan R; Mammel, Mark K; Lacher, David W; Elkins, Christopher A

    2016-01-01

    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 closely related E

  19. Strain-Level Discrimination of Shiga Toxin-Producing Escherichia coli in Spinach Using Metagenomic Sequencing.

    Directory of Open Access Journals (Sweden)

    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

  20. Human extraintestinal pathogenic Escherichia coli strains differ in prevalence of virulence factors, phylogroups, and bacteriocin determinants.

    Science.gov (United States)

    Micenková, Lenka; Bosák, Juraj; Vrba, Martin; Ševčíková, Alena; Šmajs, David

    2016-09-20

    The study used a set of 407 human extraintestinal pathogenic E. coli strains (ExPEC) isolated from (1) skin and soft tissue infections, (2) respiratory infections, (3) intra-abdominal infections, and (4) genital smears. The set was tested for bacteriocin production, for prevalence of bacteriocin and virulence determinants, and for phylogenetic typing. Results obtained from the group of ExPEC strains were compared to data from our previously published analyses of 1283 fecal commensal E. coli strains. The frequency of bacteriocinogeny was significantly higher in the set of ExPEC strains (63.1 %), compared to fecal E. coli (54.2 %; p production of microcin M and lower production of microcin B17, colicin Ib, and Js was detected in the set of ExPEC strains. ExPEC strains had a significantly higher prevalence of phylogenetic group B2 (52.6 %) compared to fecal E. coli strains (38.3 %; p bacteriocin production, prevalence of several bacteriocin and virulence determinants, and prevalence of phylogenetic groups. Differences in these parameters were also identified within subgroups of ExPEC strains of diverse origin. While some microcin determinants (mM, mH47) were associated with virulent strains, other bacteriocin types (mB17, Ib, and Js) were associated with fecal flora.

  1. CHARACTERIZATION OF EXTENDED-SPECTRUM Β-LACTAMASE-PRODUCING ESCHERICHIA COLI STRAINS ISOLATED FROM DAIRY PRODUCTS

    Directory of Open Access Journals (Sweden)

    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.

  2. Towards understanding inter-strain attachment variations of Escherichia coli during transport in saturated quartz sand.

    Science.gov (United States)

    Foppen, Jan Willem; Lutterodt, George; Röling, Wilfred F M; Uhlenbrook, Stefan

    2010-02-01

    Although Escherichia coli is an indicator of fecal contamination in aquifers, limited research has been devoted to understanding the biological processes involved in the initial attachment of E. coli transported in abiotic porous media. The roles of the various surface structures of E. coli, like lipopolysaccharides (LPS), autotransporter proteins, and fimbriae are unknown. The objective of this research was to establish the effects of variations in surface characteristics of the outer membrane of E. coli on the attachment efficiency of 54 E. coli strains upon transport in saturated quartz sand under identical flow conditions. We used column experiments to assess retention of the E. coli strains, and we determined sphericity, motility, zeta-potential, and aggregation of all strains. LPS composition was determined based on known serotypes, and the presence/absence of 22 genes encoding surface characteristics was determined with qualitative PCR. The results indicated that under identical flow conditions, there was a variation of two orders of magnitude in the maximum breakthrough concentrations of the 54 E. coli strains. Of all factors we investigated, no single factor was able to explain attachment efficiency variations statistically significantly. However, low attachment efficiencies were associated (p=0.13) with LPS containing saccharides with phosphate and/or carboxyl groups. These saccharide groups are acidic and likely charged with a negative O-atom, which reduced attachment to the negatively charged quartz surface. In addition, of the 22 genes tested, Afa was most associated (p=0.21) with attachment efficiency. The work presented here bridges knowledge on colloid transport and molecular microbiology, and tries to offer a more holistic view on the attachment of planktonic E. coli bacteria to (abiotic) quartz grain surfaces. Future research should involve the use of microbiological techniques in order to be able to map the unique or grouped characteristics of E

  3. Survival and resuscitation of ten strains of Campylobacter jejuni and Campylobacter coli under acid conditions

    NARCIS (Netherlands)

    Chaveerach, P.; Huurne, ter A.A.H.M.; Lipman, L.J.A.; Knapen, van F.

    2003-01-01

    The culturability of 10 strains of Campylobacter jejuni and Campylobacter coli was studied after the bacteria were exposed to acid conditions for various periods of time. Campylobacter cells could not survive 2 h under acid conditions (formic acid at pH 4). The 10 Campylobacter strains could not be

  4. Whole-genome sequence of Escherichia coli serotype O157:H7 strain B6914-ARS

    Science.gov (United States)

    Escherichia coli serotype O157:H7 strain B6914-MS1 is a Shiga toxin-deficient human fecal isolate obtained by the Centers for Disease Control and Prevention that has been used extensively in applied research studies. Here we report the genome sequence of strain B6914-ARS, a B6914-MS1 clone that has ...

  5. Isolation and characterization of the E. coli membrane protein production strain Mutant56(DE3)

    DEFF Research Database (Denmark)

    Baumgarten, Thomas; Schlegel, Susan; Wagner, Samuel

    2017-01-01

    Membrane protein production is usually toxic to E. coli. However, using genetic screens strains can be isolated in which the toxicity of membrane protein production is reduced, thereby improving production yields. Best known examples are the C41(DE3) and C43(DE3) strains, which are both derived...

  6. Isolation and characterization of the E. coli membrane protein production strain Mutant56(DE3)

    NARCIS (Netherlands)

    Baumgarten, Thomas; Schlegel, Susan; Wagner, Samuel; Löw, Mirjam; Eriksson, Jonas; Bonde, Ida; Herrgård, Markus J; Heipieper, Hermann J; Nørholm, Morten H H; Slotboom, Dirk Jan; de Gier, Jan-Willem

    2017-01-01

    Membrane protein production is usually toxic to E. coli. However, using genetic screens strains can be isolated in which the toxicity of membrane protein production is reduced, thereby improving production yields. Best known examples are the C41(DE3) and C43(DE3) strains, which are both derived from

  7. Combinatorial Strategies for Improving Multiple-Stress Resistance in Industrially Relevant Escherichia coli Strains

    DEFF Research Database (Denmark)

    Lennen, Rebecca; Herrgard, Markus

    2014-01-01

    microorganisms that are more tolerant toward these typical processing conditions. In this study, the growth of six industrially relevant strains of Escherichia coli was characterized under eight stress conditions representative of fed-batch fermentation, and strains W and BL21(DE3) were selected as platforms...

  8. [Frequency of isolation and susceptibility to antibiotics of Escherichia coli strains isolated from blood].

    Science.gov (United States)

    Białucha, Agata; Budzyńska, Anna; Kozuszko, Sylwia; Gospodarek, Eugenia

    2010-01-01

    The aim of our study was the analysis of Escherichia coli strains obtained from patients of University Hospital No 1 of dr A. Jurasz Collegium Medicum of L. Rydygier in Bydgoszcz Nicolaus Copernicus University in Toruń and State Infectious Diseases Observatory Hospital of T. Browicz in Bydgoszcz, between 2007 and 2010. Among all microorganisms isolated from blood was 8.7% E. coli strains and 45.1% of all rods from Enterobacteriaceae family. Number of E. coli isolations from positive blood samples was: 64 in 2007, 69 in 2008, 77 in 2009 and 26 in the first half of 2010 year. The highest percentage of E. coli strains were obtained from patients of the Transplantology and Surgery Clinic (16.1%), the Nephrology and Internal Diseases Clinic with the Dialysis Centre (14.0%), the Pediatric, Hematology and Oncology Clinic (13.6%) and the Anesthesiology and Intensive Care Clinic (13.6%). All analysed strains were susceptible to carbapenems, amikacin and tygecycline. The highest percentage of resistant strains were observed to ampicillin (70.7%), piperacillin (43.9%), tetracycline (42.8%) and doxycycline (38.8%). During four years of study 4 (6.3%), one, three and two E. coli strains with ESBL were isolated, respectively.

  9. Transcriptional Control of Dual Transporters Involved in α-Ketoglutarate Utilization Reveals Their Distinct Roles in Uropathogenic Escherichia coli.

    Science.gov (United States)

    Cai, Wentong; Cai, Xuwang; Yang, Yongwu; Yan, Shigan; Zhang, Haibin

    2017-01-01

    Uropathogenic Escherichia coli (UPEC) are the primary causative agents of urinary tract infections. Some UPEC isolates are able to infect renal proximal tubule cells, and can potentially cause pyelonephritis. We have previously shown that to fulfill their physiological roles renal proximal tubule cells accumulate high concentrations of α-ketoglutarate (KG) and that gene cluster c5032-c5039 contribute to anaerobic utilization of KG by UPEC str. CFT073, thereby promoting its in vivo fitness. Given the importance of utilizing KG for UPEC, this study is designed to investigate the roles of two transporters KgtP and C5038 in KG utilization, their transcriptional regulation, and their contributions to UPEC fitness in vivo. Our phylogenetic analyses support that kgtP is a widely conserved locus in commensal and pathogenic E. coli, while UPEC-associated c5038 was acquired through horizontal gene transfer. Global anaerobic transcriptional regulators Fumarate and nitrate reduction (FNR) and ArcA induced c5038 expression in anaerobiosis, and C5038 played a major role in anaerobic growth on KG. KgtP was required for aerobic growth on KG, and its expression was repressed by FNR and ArcA under anaerobic conditions. Analyses of FNR and ArcA binding sites and results of EMS assays suggest that FNR and ArcA likely inhibit kgtP expression through binding to the -35 region of kgtP promoter and occluding the occupancy of RNA polymerases. Gene c5038 can be specifically induced by KG, whereas the expression of kgtP does not respond to KG, yet can be stimulated during growth on glycerol. In addition, c5038 and kgtP expression were further shown to be controlled by different alternative sigma factors RpoN and RpoS, respectively. Furthermore, dual-strain competition assays in a murine model showed that c5038 mutant but not kgtP mutant was outcompeted by the wild-type strain during the colonization of murine bladders and kidneys, highlighting the importance of C5038 under in vivo

  10. Molecular screening of pathogenic Escherichia coli strains isolated from dairy neonatal calves in Cordoba province, Argentina.

    Science.gov (United States)

    Picco, Natalia Y; Alustiza, Fabrisio E; Bellingeri, Romina V; Grosso, María C; Motta, Carlos E; Larriestra, Alejandro J; Vissio, Claudina; Tiranti, Karina I; Terzolo, Horacio R; Moreira, Ana R; Vivas, Adriana B

    2015-01-01

    The aim of this study was to perform a current molecular characterization of bovine pathogenic Escherichia coli strains isolated from random samplings in Argentinean dairy farms. Rectal swabs were obtained from 395 (63.7%) healthy and 225 (36.3%) diarrheic calves, belonging to 45 dairy farms in Cordoba Province, Argentina. E. coli isolates were examined for virulence genes (f5, f41, f17, sta, stb, lt, eae, vt) using PCR and the prevalence of E. coli virulence profiles was spatially described in terms of spatial distribution. A total of 30.1% isolates were found to be positive for at least one of the virulence genes. Depending on the different gene combinations present, 11 virulence profiles were found. Most of the isolates analyzed had a single gene, and no combination of fimbrial and enterotoxin gene was predominant. There was no association between the frequency and distribution of E. coli virulence genes and calf health status. Most of the virulence profiles were compatible with ETEC strains and showed a homogeneous distribution over the sampled area. A clustering pattern for E. coli virulence profiles could not be recognized. This work provides updated information on the molecular characterization of pathogenic E. coli strains from dairy herds in Cordoba, Argentina. These findings would be important to formulate prevention programs and effective therapies for diarrhea in calves caused by E. coli. Copyright © 2014 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.

  11. Genetic Evaluation of E. coli Strains Isolated from Asymptomatic Children with Neurogenic Bladders

    Directory of Open Access Journals (Sweden)

    John Kryger

    2015-01-01

    Full Text Available This study was conducted to describe the genetic profiles of E. coli that colonize asymptomatic pediatric neurogenic bladders. E. coli was isolated from 25 of 80 urine samples. Patients were excluded if they presented with symptomatic urinary tract infection or received treatment with antibiotics in the preceding three months. Multiplex PCR was performed to determine E. coli phylotype (A, B1, B2, and D and the presence of seven pathogenicity islands (PAIs and 10 virulence factors (VFs. E. coli strains were predominantly of the B1 and B2 phylotype, with few strains in the A or D phylotype. The PAIs IV536, ICFT073, and IICFT073 had the highest prevalence: 76%, 64%, and 48%, respectively. The PAIs II536, IJ96, and IIJ96 were less prevalent: 28%, 20%, and 24%, respectively. The most prevalent VF was vat (40%, while the least prevalent VFs were sfa (8% and iha (12%. None of the strains carried the VF fyuA, which is very common in uropathogenic E. coli (UPEC. The genetic profiles of E. coli in this cohort seem to be more similar to UPEC than to commensal E. coli. However, they appear to have reduced virulence potential that allows them to colonize asymptomatically.

  12. Risk factors for fecal colonization with multiple distinct strains of Escherichia coli among long-term care facility residents.

    Science.gov (United States)

    Lautenbach, Ebbing; Tolomeo, Pam; Black, Nicole; Maslow, Joel N

    2009-05-01

    Of 49 long-term care facility residents, 21 (43%) were colonized with 2 or more distinct strains of Escherichia coli. There were no significant risk factors for colonization with multiple strains of E. coli. These results suggest that future efforts to efficiently identify the diversity of colonizing strains will be challenging.

  13. [Antibioresistance of Escherichia coli strains isolated from raw chicken meat in Senegal].

    Science.gov (United States)

    Fofana, A; Bada Alambedji, R; Seydi, M; Akakpo, A J

    2006-01-01

    Antimicrobial-resistant Escherichia coli and others pathogens bacteria can be transferred from animals to humans through consumption of contaminated food and foods products and thus present a public health risk. The increase in E. coli resistance to commonly used antimicrobials both in the public health and veterinary sectors is one of the major threats of health care worldwide. The present study was undertaken to estimate the antimicrobial resistance of E. coli isolates from raw chicken meat in Dakar. Levying of skin and muscle have been carried out on 120 chicken carcasses bought from 13 sale points and 23 flocks beetween November 2003 and April 2004. 102 Escherichia coli strains have been isolated, among which, 90 were tested for their susceptibilities to 16 selected antibiotics by agar diffusion method. All Escherichia coli strains (100%), were resistant to one or more antibiotic; 60 strains (66.66%) being resistant to more than five antibiotics. Those frequently encountererd are: ampicillin, trimethoprim, trimethoprim-sulfametoxazole, tetracycline, sulfonamides, streptomycin, nalidixic acid. Multiple resistances to 12 antibiotics were also observed. The lowest resistances were noted with gentamicin (3.33%) and neomycin (5.56%). This study showed the significance of chicken meat as source of Escherichia coli strains with a simple or multiple resistance to various antibiotics tested. Further studies are necessary in order to determine bacterium mechanisms of resistance.

  14. Resistance to drugs and heavy metals, colicin production, and biochemical characteristics of selected bovine and porcine Escherichia coli strains.

    OpenAIRE

    Harnett, N M; Gyles, C L

    1984-01-01

    A study was made of resistance to heavy metals and antibiotics, biochemical characteristics, and colicinogeny in selected strains of Escherichia coli of O serogroups 8, 9, 20, 64, 101, and X46. Of 42 strains that were investigated, 26 were porcine enterotoxigenic E. coli (ETEC), 8 were porcine non-enterotoxigenic E. coli (NETEC), and 8 were bovine ETEC. Multiple resistance to antimicrobial agents was common among the strains, and resistance to chloramphenicol and kanamycin was less common tha...

  15. Engineering of a plasmid-free Escherichia coli strain for improved in vivo biosynthesis of astaxanthin

    Directory of Open Access Journals (Sweden)

    Steuer Kristin

    2011-04-01

    Full Text Available Abstract Background The xanthophyll astaxanthin is a high-value compound with applications in the nutraceutical, cosmetic, food, and animal feed industries. Besides chemical synthesis and extraction from naturally producing organisms like Haematococcus pluvialis, heterologous biosynthesis in non-carotenogenic microorganisms like Escherichia coli, is a promising alternative for sustainable production of natural astaxanthin. Recent achievements in the metabolic engineering of E. coli strains have led to a significant increase in the productivity of carotenoids like lycopene or β-carotene by increasing the metabolic flux towards the isoprenoid precursors. For the heterologous biosynthesis of astaxanthin in E. coli, however, the conversion of β-carotene to astaxanthin is obviously the most critical step towards an efficient biosynthesis of astaxanthin. Results Here we report the construction of the first plasmid-free E. coli strain that produces astaxanthin as the sole carotenoid compound with a yield of 1.4 mg/g cdw (E. coli BW-ASTA. This engineered E. coli strain harbors xanthophyll biosynthetic genes from Pantoea ananatis and Nostoc punctiforme as individual expression cassettes on the chromosome and is based on a β-carotene-producing strain (E. coli BW-CARO recently developed in our lab. E. coli BW-CARO has an enhanced biosynthesis of the isoprenoid precursor isopentenyl diphosphate (IPP and produces β-carotene in a concentration of 6.2 mg/g cdw. The expression of crtEBIY along with the β-carotene-ketolase gene crtW148 (NpF4798 and the β-carotene-hydroxylase gene (crtZ under controlled expression conditions in E. coli BW-ASTA directed the pathway exclusively towards the desired product astaxanthin (1.4 mg/g cdw. Conclusions By using the λ-Red recombineering technique, genes encoding for the astaxanthin biosynthesis pathway were stably integrated into the chromosome of E. coli. The expression levels of chromosomal integrated recombinant

  16. Host Response to Porcine Strains of Escherichia coli in a Novel Pyelonephritis Model

    DEFF Research Database (Denmark)

    Isling, L. K.; Aalbæk, B.; Birck, M. M.

    2011-01-01

    The initial pathology and pathogenesis of pyelonephritis and the influence of different strains of Escherichia coli were investigated in a novel porcine model. Nine female pigs were divided into three groups (A, B and C) and inoculated repeatedly into one renal pelvis with porcine pyelonephritis E......, liver and spleen were performed by quantitative, semiquantitative and/or descriptive methods. Immunohistochemistry was used to identify cells expressing L1 antigen, CD3ɛ, CD4, CD8, CD79αcy and lysozyme, and to identify E. coli and Tamm-Horsfall protein (THP). E. coli was re-isolated from all inoculated....... coli strain LK67 (P fimbriae PapGI), LK76 (type 1 fimbriae) or LK82 (type 1 fimbriae and P fimbriae PapGII/III), respectively. The contralateral kidneys were inoculated with saline and served as controls. Pigs were killed 6h post-inoculation (hpi). Differential leucocyte counts, serum biochemical...

  17. Shigella strains are not clones of Escherichia coli but sister species in the genus Escherichia.

    Science.gov (United States)

    Zuo, Guanghong; Xu, Zhao; Hao, Bailin

    2013-02-01

    Shigella species and Escherichia coli are closely related organisms. Early phenotyping experiments and several recent molecular studies put Shigella within the species E. coli. However, the whole-genome-based, alignment-free and parameter-free CVTree approach shows convincingly that four established Shigella species, Shigella boydii, Shigella sonnei, Shigella felxneri and Shigella dysenteriae, are distinct from E. coli strains, and form sister species to E. coli within the genus Escherichia. In view of the overall success and high resolution power of the CVTree approach, this result should be taken seriously. We hope that the present report may promote further in-depth study of the Shigella-E. coli relationship. Copyright © 2013. Production and hosting by Elsevier Ltd.

  18. Comparison of the serum sensitivity of uropathogenic strains of Escherichia coli isolated from different diagnostic groups

    Directory of Open Access Journals (Sweden)

    J. Vraneš,

    2005-02-01

    Full Text Available The bactericidal activity of serum caused by complement system is an important defence mechanism protecting the host organism against infection. The capacity to resist bactericidal activity of normal human serum contributes to the virulence of many gram-negative pathogens. Serum resistance in bacteria has been attributed to their surface components, but exact mechanism of resistance which most likely involves multiple factors is not well understood. In this study, the capacity of Escherichia coli to resist the bactericidal action of serum was examined in 85 clinical isolates obtained from patients with acute pyelonephritis (n=23, acute cystitis (n=22, chronic pyelonephritis (n=22 and asymptomatic bacteriuria (n=18. Serum sensitivity was also examined in relation to the serogroup specificity and expression of the different adhesins of the strains.Bacterial susceptibility to serum killing was measured by assessing regrowth after incubation in serum according to Schiller and Hatch method. The adhesins of E. coli were determined by hemagglutination and inhibition of hemagglutiation, and serotyping was performed on glass slides and confirmed using a mechanized microtechnique.The significant correlation between serum resistance of uropathogenic strains of E. coli and expression of P-fimbriae and O6 serogroup was observed.Theincidence of serum-resistant E. coli strains was significantly higher in strains isolated from urine of patients with acute pyelonephritis, as compared to strains isolated in other diagnostic groups, which is in accordance with higher virulence and invasive potential of these strains.

  19. EcoR phylogenetic analysis and virulence genotyping of avian pathogenic Escherichia coli strains and Escherichia coli isolates from commercial chicken carcasses in southern Brazil.

    Science.gov (United States)

    Kobayashi, Renata K T; Aquino, Ivani; Ferreira, Ana Lívia da S; Vidotto, Marilda C

    2011-05-01

    Escherichia coli strains designated as avian pathogenic E. coli (APEC) are responsible for avian colibacillosis, an acute and largely systemic disease that promotes significant economic losses in poultry industry worldwide because of mortality increase, medication costs, and condemnation of carcasses. APEC is a subgroup of extraintestinal pathogenic E. coli pathotype, which includes uropathogenic E. coli, neonatal meningitis E. coli, and septicemic E. coli. We isolated E. coli from commercial chicken carcasses in a Brazilian community and compared by polymerase chain reaction-defined phylogenetic group (A, B1, B2, or D) with APEC strains isolated from sick chickens from different poultry farms. A substantial number of strains assigned to phylogenetic E. coli reference collection group B2, which is known to harbor potent extraintestinal human and animal E. coli pathogens, were identified as APEC (26.0%) in both commercial chicken carcasses and retail poultry meat (retail poultry E. coli [RPEC]) (21.25%). The majority of RPEC were classified as group A (35%), whereas the majority of APEC were groups B1 (30.8) and A (27.6%). APEC and RPEC presented the genes pentaplex, iutA, hly, iron, ompT, and iss, but with different virulence profiles. The similarity between APEC and RPEC indicates RPEC as potentially pathogenic strains and supports a possible zoonotic risk for humans.

  20. Characterization of a Large Antibiotic Resistance Plasmid Found in Enteropathogenic Escherichia coli Strain B171 and Its Relatedness to Plasmids of Diverse E. coli and Shigella Strains.

    Science.gov (United States)

    Hazen, Tracy H; Michalski, Jane; Nagaraj, Sushma; Okeke, Iruka N; Rasko, David A

    2017-09-01

    Enteropathogenic Escherichia coli (EPEC) is a leading cause of severe infantile diarrhea in developing countries. Previous research has focused on the diversity of the EPEC virulence plasmid, whereas less is known regarding the genetic content and distribution of antibiotic resistance plasmids carried by EPEC. A previous study demonstrated that in addition to the virulence plasmid, reference EPEC strain B171 harbors a second, larger plasmid that confers antibiotic resistance. To further understand the genetic diversity and dissemination of antibiotic resistance plasmids among EPEC strains, we describe the complete sequence of an antibiotic resistance plasmid from EPEC strain B171. The resistance plasmid, pB171_90, has a completed sequence length of 90,229 bp, a GC content of 54.55%, and carries protein-encoding genes involved in conjugative transfer, resistance to tetracycline (tetA), sulfonamides (sulI), and mercury, as well as several virulence-associated genes, including the transcriptional regulator hha and the putative calcium sequestration inhibitor (csi). In silico detection of the pB171_90 genes among 4,798 publicly available E. coli genome assemblies indicates that the unique genes of pB171_90 (csi and traI) are primarily restricted to genomes identified as EPEC or enterotoxigenic E. coli However, conserved regions of the pB171_90 plasmid containing genes involved in replication, stability, and antibiotic resistance were identified among diverse E. coli pathotypes. Interestingly, pB171_90 also exhibited significant similarity with a sequenced plasmid from Shigella dysenteriae type I. Our findings demonstrate the mosaic nature of EPEC antibiotic resistance plasmids and highlight the need for additional sequence-based characterization of antibiotic resistance plasmids harbored by pathogenic E. coli. Copyright © 2017 American Society for Microbiology.

  1. Antimicrobial Resistant Pattern of Escherichia Coli Strains Isolated from Pediatric Patients in Jordan

    Directory of Open Access Journals (Sweden)

    Mohammad Alshara

    2011-05-01

    Full Text Available The present study was conducted to investigate antimicrobial resistant pattern of Escherichia coli (E. coli strains isolated from clinical specimens of Jordanian pediatric patients during the period from January to December 2008. A total of 444 E. coli strains were isolated from clinical specimens and tested for their susceptibility to different antimicrobial drugs. Overall, high resistance rate was observed for ampicillin (84%, followed by amoxicillin-clavulanic acid (74.3%, cotrimoxazole (71%, nalidixic acid (47.3%, cephalothin (41%. Lower resistance rates were observed for amikacin (0% followed by Cefotaxime (11%, Ceftriaxone (11.7%, ciprofloxacin (14.5%, Norfloxacin (16.5%, gentamicin (17.3% cephalexin (20.9%, Ceftazidime (22.5%, cefixime (29.6%, and cefaclor (32.8%. Ampicillin, amoxicillin-clavulanic acid and cotrimoxazole were found to be ineffective at in vitro inhibition of the E. coli of pediatric origin. Amikacin was highly effective for E. coli with susceptibility rate of 100%. The majority of E. coli strains were susceptible to third generation cephalosporins and fluoroquinolones.

  2. Virulence genes, antibiotic resistance and integrons in Escherichia coli strains isolated from synanthropic birds from Spain.

    Science.gov (United States)

    Sacristán, C; Esperón, F; Herrera-León, S; Iglesias, I; Neves, E; Nogal, V; Muñoz, M J; de la Torre, A

    2014-01-01

    The aim of this study was to determine the presence of virulence genes and antibiotic resistance profiles in 164 Escherichia coli strains isolated from birds (feral pigeons, hybrid ducks, house sparrows and spotless starlings) inhabiting urban and rural environments. A total of eight atypical enteropathogenic E. coli strains were identified: one in a house sparrow, four in feral pigeons and three in spotless starlings. Antibiotic resistance was present in 32.9% (54) of E. coli strains. The dominant type of resistance was to tetracycline (21.3%), ampicillin (19.5%) and sulfamethoxazole (18.9%). Five isolates had class 1 integrons containing gene cassettes encoding for dihydrofolate reductase A (dfrA) and aminoglycoside adenyltransferase A (aadA), one in a feral pigeon and four in spotless starlings. To our knowledge, the present study constitutes the first detection of virulence genes from E. coli in spotless starlings and house sparrows, and is also the first identification worldwide of integrons containing antibiotic resistance gene cassettes in E. coli strains from spotless starlings and pigeons.

  3. Efficient recovery of fluoroquinolone-susceptible and fluoroquinolone-resistant Escherichia coli strains from frozen samples.

    Science.gov (United States)

    Lautenbach, Ebbing; Santana, Evelyn; Lee, Abby; Tolomeo, Pam; Black, Nicole; Babson, Andrew; Perencevich, Eli N; Harris, Anthony D; Smith, Catherine A; Maslow, Joel

    2008-04-01

    We assessed the rate of recovery of fluoroquinolone-resistant and fluoroquinolone-susceptible Escherichia coli isolates from culture of frozen perirectal swab samples compared with the results for culture of the same specimen before freezing. Recovery rates for these 2 classes of E. coli were 91% and 83%, respectively. The majority of distinct strains recovered from the initial sample were also recovered from the frozen sample. The strains that were not recovered were typically present only in low numbers in the initial sample. These findings emphasize the utility of frozen surveillance samples.

  4. Engineering of an Escherichia coli strain for the production of 3-methyl-1-butanol.

    Science.gov (United States)

    Connor, Michael R; Liao, James C

    2008-09-01

    3-Methyl-1-butanol is a potential fuel additive or substitute. Previously this compound was identified in small quantities in yeast fermentation as one of the fusel alcohols. In this work, we engineered an Escherichia coli strain to produce 3-methyl-1-butanol from glucose via the host's amino acid biosynthetic pathways. Strain improvement with the removal of feedback inhibition and competing pathways increased the selectivity and productivity of 3-methyl-1-butanol. This work demonstrates the feasibility of production of 3-methyl-1-butanol as a biofuel and shows promise in using E. coli as a host for production.

  5. Virulence genes of Escherichia coli strains isolated from mastitic milk.

    Science.gov (United States)

    Bean, A; Williamson, J; Cursons, R T

    2004-08-01

    Escherichia coli, a Gram-negative environmental pathogen associated with bovine mastitis was isolated from the milk of 34 symptomatic cows that had been diagnosed with clinical mastitis. Eighty isolates were obtained over a 17-month period and these isolates were screened by DNA amplification for the following E. coli virulence genes: cnf1, cnf2, eaeA, eagg, einv, ltx1, stx1, stx2 and vt2e. Thirty of the bacterial isolates, obtained from 23 different cows, had toxin genes identified in their DNA. The most common virulence gene detected was stx1, with a prevalence of 31%, followed by cnf2 (7.5%), vt2e (6.25%) and eaeA (4%). The possession of different virulence genes by the bacterial isolates had no discernable impact on the health status of the cows as there was no correlation between the potential for toxin production by the E. coli isolates and the systemic clinical condition of the respective infected cows.

  6. Pathophysiology of Escherichia coli ventilator-associated pneumonia: implication of highly virulent extraintestinal pathogenic strains.

    Science.gov (United States)

    Messika, Jonathan; Magdoud, Fatma; Clermont, Olivier; Margetis, Dimitri; Gaudry, Stéphane; Roux, Damien; Branger, Catherine; Dreyfuss, Didier; Denamur, Erick; Ricard, Jean-Damien

    2012-12-01

    To characterize Escherichia coli ventilator-associated pneumonia (VAP) in intensive care unit (ICU) patients by determining antibioresistance and genotypic characteristics of E. coli isolates responsible for VAP or lung colonization, by comparing them with their oropharyngeal and rectal counterparts and by assessing representative isolates' virulence in a pneumonia mouse model. Patients under mechanical ventilation for more than 72 h were screened for simultaneous presence of E. coli in rectal, oropharyngeal, and respiratory samples (colonization or VAP). If present, E. coli isolates were characterized by antimicrobial susceptibility, phylogenetic grouping, and virulence factor (VF) gene content determination. BALB/c mice were challenged intranasally with 3.6 × 10(8) colony-forming units (CFU) of patients' E. coli isolates. Multisite E. coli colonization was observed in 19 % of patients (25 patients, 12 with E. coli VAP). One hundred fifteen distinct E. coli isolates were analyzed. B2 phylogenetic group was predominant, with high VF gene content and low antimicrobial resistance. Antimicrobial resistance diversity was observed in four patients with VAP. E. coli isolates from VAP patients were more frequently B2 isolates, with significantly greater VF gene content than lung colonization isolates. Among screened VF genes, iroN and sfa appeared important for lung infection. A very strong correlation (R (2) = 0.99) was found between VF gene content and mortality in the mouse model. This is the first study establishing antibioresistance and genotypic characteristics of E. coli isolates responsible for VAP in adult ICU patients. These isolates are highly virulent specific extraintestinal pathogenic E. coli strains expressing virulence factors, representing potential targets for new therapies.

  7. Genome-scale metabolic reconstructions of multiple Escherichia coli strains highlight strain-specific adaptations to nutritional environments.

    Science.gov (United States)

    Monk, Jonathan M; Charusanti, Pep; Aziz, Ramy K; Lerman, Joshua A; Premyodhin, Ned; Orth, Jeffrey D; Feist, Adam M; Palsson, Bernhard Ø

    2013-12-10

    Genome-scale models (GEMs) of metabolism were constructed for 55 fully sequenced Escherichia coli and Shigella strains. The GEMs enable a systems approach to characterizing the pan and core metabolic capabilities of the E. coli species. The majority of pan metabolic content was found to consist of alternate catabolic pathways for unique nutrient sources. The GEMs were then used to systematically analyze growth capabilities in more than 650 different growth-supporting environments. The results show that unique strain-specific metabolic capabilities correspond to pathotypes and environmental niches. Twelve of the GEMs were used to predict growth on six differentiating nutrients, and the predictions were found to agree with 80% of experimental outcomes. Additionally, GEMs were used to predict strain-specific auxotrophies. Twelve of the strains modeled were predicted to be auxotrophic for vitamins niacin (vitamin B3), thiamin (vitamin B1), or folate (vitamin B9). Six of the strains modeled have lost biosynthetic pathways for essential amino acids methionine, tryptophan, or leucine. Genome-scale analysis of multiple strains of a species can thus be used to define the metabolic essence of a microbial species and delineate growth differences that shed light on the adaptation process to a particular microenvironment.

  8. Improvement of Escherichia coli production strains by modification of the phosphoenolpyruvate:sugar phosphotransferase system

    Directory of Open Access Journals (Sweden)

    Gosset Guillermo

    2005-05-01

    Full Text Available Abstract The application of metabolic engineering in Escherichia coli has resulted in the generation of strains with the capacity to produce metabolites of commercial interest. Biotechnological processes with these engineered strains frequently employ culture media containing glucose as the carbon and energy source. In E. coli, the phosphoenolpyruvate:sugar phosphotransferase system (PTS transports glucose when this sugar is present at concentrations like those used in production fermentations. This protein system is involved in phosphoenolpyruvate-dependent sugar transport, therefore, its activity has an important impact on carbon flux distribution in the phosphoenolpyruvate and pyruvate nodes. Furthermore, PTS has a very important role in carbon catabolite repression. The properties of PTS impose metabolic and regulatory constraints that can hinder strain productivity. For this reason, PTS has been a target for modification with the purpose of strain improvement. In this review, PTS characteristics most relevant to strain performance and the different strategies of PTS modification for strain improvement are discussed. Functional replacement of PTS by alternative phosphoenolpyruvate-independent uptake and phosphorylation activities has resulted in significant improvements in product yield from glucose and productivity for several classes of metabolites. In addition, inactivation of PTS components has been applied successfully as a strategy to abolish carbon catabolite repression, resulting in E. coli strains that use more efficiently sugar mixtures, such as those obtained from lignocellulosic hydrolysates.

  9. In vitro susceptibility to mecillinam of Escherichia coli strains isolated from the urine of pregnant women.

    Science.gov (United States)

    Duployez, C; Loiez, C; Cattoen, C; Descamps, D; Wallet, F; Vachée, A

    2016-12-01

    Pivmecillinam is a safe beta-lactam for use in pregnancy. It has been widely used for the treatment of lower urinary tract infections (UTIs) in the Nordic countries where its efficacy, minor impact on the microbiota, and low level of resistance among the Escherichia coli strains have been proven. However, susceptibility data related to E. coli involved in asymptomatic bacteriuria and lower UTIs in pregnant women is lacking. We aimed to support the 2015 recommendations issued by the French Infectious Diseases Society (SPILF) on gestational UTI, with a particular focus on pivmecillinam. Antimicrobial susceptibility testing was performed by 12 hospitals with a maternity department on 235 E. coli strains isolated from the urine of pregnant women. Susceptibility to mecillinam was tested by disk diffusion method using the 2015 recommendations of the antibiogram committee of the French microbiology society (CA-SFM). Global susceptibility to mecillinam was 86.4%. Susceptibility to mecillinam was 96.5% for strains susceptible to amoxicillin-clavulanic acid and 38.7% for resistant strains. All six extended-spectrum beta-lactamase-producing E. coli strains were susceptible to mecillinam. Given the efficacy and safety of pivmecillinam during pregnancy, it may be used for the documented treatment of asymptomatic bacteriuria and acute cystitis in pregnant women. It also represents an alternative for the treatment of multidrug-resistant bacterial infections. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  10. In vitro biofilm formation of commensal and pathogenic Escherichia coli strains: impact of environmental and genetic factors

    DEFF Research Database (Denmark)

    Reisner, A.; Krogfelt, Karen; Klein, B.M.

    2006-01-01

    Our understanding of Escherichia coli biofilm formation in vitro is based on studies of laboratory K-12 strains grown in standard media. However, pathogenic E. coli isolates differ substantially in their genetic repertoire from E. coli K-12 and are subject to heterogeneous environmental condition...

  11. Simulation of the rate of transfer of antibiotic resistance between Escherichia coli strains cultured under well controlled environmental conditions

    NARCIS (Netherlands)

    Smelt, J.P.; Hoefsloot, H.C.; de Koster, C.G.; Schuurmans, J.M.; ter Kuile, B.H.; Brul, S.

    2015-01-01

    It was demonstrated that the tetracycline resistance plasmid in Escherichia coli resembling K-12 23:06 containing the E. coli plasmid DM0133 could be transferred to tetracycline sensitive E. coli K-12 MG1655 YFP. The sensitive recipient strain has a slight metabolic advantage in continuous

  12. Protective effect of oral administration of transgenic tobacco seeds against verocytotoxic Escherichia coli strain in piglets.

    Science.gov (United States)

    Rossi, Luciana; Dell'Orto, Vittorio; Vagni, Simona; Sala, Vittorio; Reggi, Serena; Baldi, Antonella

    2014-03-01

    The use of transgenic plants as delivery system for antigenic proteins is attractive for its simplicity and increases likelihood for local immune response at sites of infection. The aim of this study was to evaluate the protective effect of oral administration of tobacco seeds, expressing the FedA, the major protein of the F18 adhesive fimbriae, and B subunit of verocytotoxin, against verocytotoxin-producing E. coli (VTEC) strain in piglets. Forty-three early weaned piglets, were randomly divided into 4 experimental groups: 3 test groups and a control. Treatment groups orally received a bolus, with different dose of tobacco seeds on 0, 1, 2, 14 days post primary administration. After challenge, with 1*10(10) CFU of O138 Escherichia coli strain, piglets showed clinical scores significantly higher in the control group compared to orally immunized groups (P seeds expressing antigenic proteins against VTEC strains can induce a protective effect against challenger strain in piglets.

  13. Production of heat-stable enterotoxic component by Escherichia coli strains enteropathogenic for swine.

    Science.gov (United States)

    Kashiwazaki, M; Akaike, Y; Miyachi, T; Ogawa, T; Sugawara, M; Isayama, Y

    1981-01-01

    Forty-nine strains of Escherichia coli isolated from piglets with or without neonatal diarrhea were all negative for both classical heat-labile and heat-stable enterotoxins when examined by the 18-hour rabbit ileal loop test with culture supernatants, the mouse Y1 adrenal cell test, and the infant mouse test. Of them, seven strains from diarrhea were positive only when tested in porcine ileal loops challenged with living bacterial cell suspensions or culture supernatants. The enterotoxic component produced by them was resistant to heating at 80 degrees C for 20 minutes. It presented a rapid onset of action with a long duration, although the amount of accumulated fluid in the porcine ileal loops was small. These porcine strains of E. coli which has been positive only for the porcine ileal loop test were designated "ST pig loop" or "STpl" strains.

  14. Specific selection for virulent urinary tract infectious Escherichia coli strains during catheter-associated biofilm formation

    DEFF Research Database (Denmark)

    Ferrieres, Lionel; Hancock, Viktoria; Klemm, Per

    2007-01-01

    Biofilm-associated bacterial infections have a major impact on artificial implants such as urinary catheters, often with devastating consequences. The capacity of a microorganism to form a biofilm on a surface depends on the nature of the surface and its conditioning. When a urinary catheter...... microorganisms can attach. Urinary tract infectious (UTI) Escherichia coli range in pathogenicity and the damage they cause - from benign asymptomatic bacteriuria (ABU) strains, which inflict no or few problems to the host, to uropathogenic E. coli (UPEC) strains, which are virulent and often cause severe...... symptoms and complications. We have found that whereas ABU strains produce better biofilms on polystyrene and glass, UPEC strains have a clear competitive advantage during biofilm growth on catheter surfaces. Our results indicate that some silicone and silicone-latex catheters actually select...

  15. Mutant E. coli strain with increased succinic acid production

    Science.gov (United States)

    Donnelly, Mark; Millard, Cynthia S.; Stols, Lucy

    2001-09-25

    A method for isolating succinic acid producing bacteria is provided comprising increasing the biomass of an organism which lacks the ability to catabolize pyruvate, and then subjecting the biomass to glucose-rich medium in an anaerobic environment to enable pyruvate-catabolizing mutants to grow. The invention also provides for a mutant that produces high amounts of succinic acid, which has been derived from a parent which lacked the genes for pyruvate formate lyase and lactate dehydrogenase, and which belongs to the E.coli Group of Bacteria.

  16. Mutant E. coli strain with increased succinic acid production

    Science.gov (United States)

    Donnelly, Mark; Millard, Cynthia S.; Stols, Lucy

    1998-01-01

    A method for isolating succinic acid producing bacteria is provided comprising increasing the biomass of an organism which lacks the ability to catabolize pyruvate, and then subjecting the biomass to glucose-rich medium in an anaerobic environment to enable pyruvate-catabolizing mutants to grow. The invention also provides for a mutant that produces high amounts of succinic acid, which as been derived from a parent which lacked the genes for pyruvate formate lyase and lactate dehydrogenase, and which belongs to the E.coli Group of Bacteria.

  17. The prevalence of ESBL-producing E-coli and Klebsiella strains in the Copenhagen area of Denmark

    DEFF Research Database (Denmark)

    Kjerulf, A.; Hansen, D.S.; Sandvang, D.

    2008-01-01

    The main purpose of the study was to investigate the frequency of ESBL-producing E. coli and Klebsiella strains in the Greater Copenhagen area. Four collections of strains were investigated: A) 380 consecutive E. coli and Klebsiella isolates primarily from urine, B) 200 gentamicin-resistant E. coli...... and Klebsiella isolates primarily from urine, C) 210 consecutive E. coli isolates from blood cultures, and D) 68 cefuroxime-resistant E. coli and Klebsiella isolates primarily from urine. Only one strain per patient was included. Strains with a zone diameter for cefpodoxime ...). In conclusion, the frequency of ESBL-producing E. coli and Klebsiella isolates was low in the Copenhagen area of Denmark (0.8 %). The most common ESBL genes found in our study were ctx-m and shv genes Udgivelsesdato: 2008/2...

  18. An Improved Binary Vector and Escherichia coli Strain for Agrobacterium tumefaciens-Mediated Plant Transformation.

    Science.gov (United States)

    Watson, Michael R; Lin, Yu-Fei; Hollwey, Elizabeth; Dodds, Rachel E; Meyer, Peter; McDowall, Kenneth J

    2016-07-07

    The plasmid vector pGreenII is widely used to produce plant transformants via a process that involves propagation in Escherichia coli However, we show here that pGreenII-based constructs can be unstable in E. coli as a consequence of them hampering cell division and promoting cell death. In addition, we describe a new version of pGreenII that does not cause these effects, thereby removing the selective pressure for mutation, and a new strain of E. coli that better tolerates existing pGreenII-based constructs without reducing plasmid yield. The adoption of the new derivative of pGreenII and the E. coli strain, which we have named pViridis and MW906, respectively, should help to ensure the integrity of genes destined for study in plants while they are propagated and manipulated in E. coli The mechanism by which pGreenII perturbs E. coli growth appears to be dysregulation within the ColE1 origin of replication. Copyright © 2016 Watson et al.

  19. An Improved Binary Vector and Escherichia coli Strain for Agrobacterium tumefaciens-Mediated Plant Transformation

    Directory of Open Access Journals (Sweden)

    Michael R. Watson

    2016-07-01

    Full Text Available The plasmid vector pGreenII is widely used to produce plant transformants via a process that involves propagation in Escherichia coli. However, we show here that pGreenII-based constructs can be unstable in E. coli as a consequence of them hampering cell division and promoting cell death. In addition, we describe a new version of pGreenII that does not cause these effects, thereby removing the selective pressure for mutation, and a new strain of E. coli that better tolerates existing pGreenII-based constructs without reducing plasmid yield. The adoption of the new derivative of pGreenII and the E. coli strain, which we have named pViridis and MW906, respectively, should help to ensure the integrity of genes destined for study in plants while they are propagated and manipulated in E. coli. The mechanism by which pGreenII perturbs E. coli growth appears to be dysregulation within the ColE1 origin of replication.

  20. Production of d-lactate using a pyruvate-producing Escherichia coli strain.

    Science.gov (United States)

    Akita, Hironaga; Nakashima, Nobutaka; Hoshino, Tamotsu

    2017-07-01

    To generate an organism capable of producing d-lactate, NAD + -dependent d-lactate dehydrogenase was expressed in our pyruvate-producing strain, Escherichia coli strain LAFCPCPt-accBC-aceE. After determining the optimal culture conditions for d-lactate production, 18.4 mM d-lactate was produced from biomass-based medium without supplemental mineral or nitrogen sources. Our results show that d-lactate can be produced in simple batch fermentation processes.

  1. Metaproteomics analyses as diagnostic tool for differentiation of Escherichia coli strains in outbreaks

    Science.gov (United States)

    Jabbour, Rabih E.; Wright, James D.; Deshpande, Samir V.; Wade, Mary; McCubbin, Patrick; Bevilacqua, Vicky

    2013-05-01

    The secreted proteins of the enterohemorrhagic and enteropathogenic E. coli (EHEC and EPEC) are the most common cause of hemorrhagic colitis, a bloody diarrhea with EHEC infection, which often can lead to life threatening hemolytic-uremic syndrome (HUS).We are employing a metaproteomic approach as an effective and complimentary technique to the current genomic based approaches. This metaproteomic approach will evaluate the secreted proteins associated with pathogenicity and utilize their signatures as differentiation biomarkers between EHEC and EPEC strains. The result showed that the identified tryptic peptides of the secreted proteins extracted from different EHEC and EPEC growths have difference in their amino acids sequences and could potentially utilized as biomarkers for the studied E. coli strains. Analysis of extract from EHEC O104:H4 resulted in identification of a multidrug efflux protein, which belongs to the family of fusion proteins that are responsible of cell transportation. Experimental peptides identified lies in the region of the HlyD haemolysin secretion protein-D that is responsible for transporting the haemolysin A toxin. Moreover, the taxonomic classification of EHEC O104:H4 showed closest match with E. coli E55989, which is in agreement with genomic sequencing studies that were done extensively on the mentioned strain. The taxonomic results showed strain level classification for the studied strains and distinctive separation among the strains. Comparative proteomic calculations showed separation between EHEC O157:H7 and O104:H4 in replicate samples using cluster analysis. There are no reported studies addressing the characterization of secreted proteins in various enhanced growth media and utilizing them as biomarkers for strain differentiation. The results of FY-2012 are promising to pursue further experimentation to statistically validate the results and to further explore the impact of environmental conditions on the nature of the secreted

  2. Yersiniabactin production by Pseudomonas syringae and Escherichia coli, and description of a second yersiniabactin locus evolutionary group.

    Science.gov (United States)

    Bultreys, Alain; Gheysen, Isabelle; de Hoffmann, Edmond

    2006-06-01

    The siderophore and virulence factor yersiniabactin is produced by Pseudomonas syringae. Yersiniabactin was originally detected by high-pressure liquid chromatography (HPLC); commonly used PCR tests proved ineffective. Yersiniabactin production in P. syringae correlated with the possession of irp1 located in a predicted yersiniabactin locus. Three similarly divergent yersiniabactin locus groups were determined: the Yersinia pestis group, the P. syringae group, and the Photorhabdus luminescens group; yersiniabactin locus organization is similar in P. syringae and P. luminescens. In P. syringae pv. tomato DC3000, the locus has a high GC content (63.4% compared with 58.4% for the chromosome and 60.1% and 60.7% for adjacent regions) but it lacks high-pathogenicity-island features, such as the insertion in a tRNA locus, the integrase, and insertion sequence elements. In P. syringae pv. tomato DC3000 and pv. phaseolicola 1448A, the locus lies between homologues of Psyr_2284 and Psyr_2285 of P. syringae pv. syringae B728a, which lacks the locus. Among tested pseudomonads, a PCR test specific to two yersiniabactin locus groups detected a locus in genospecies 3, 7, and 8 of P. syringae, and DNA hybridization within P. syringae also detected a locus in the pathovars phaseolicola and glycinea. The PCR and HPLC methods enabled analysis of nonpathogenic Escherichia coli. HPLC-proven yersiniabactin-producing E. coli lacked modifications found in irp1 and irp2 in the human pathogen CFT073, and it is not clear whether CFT073 produces yersiniabactin. The study provides clues about the evolution and dispersion of yersiniabactin genes. It describes methods to detect and study yersiniabactin producers, even where genes have evolved.

  3. SIMULTANEOUS EFFECTS OF SHAKING AND TEMPERATURE ON VEROTOXIN1 PHAGE INDUCTION FROM VEROTOXIGENIC ESCHERICHIA COLI STRAINS

    Directory of Open Access Journals (Sweden)

    H. Hosain Zadegan, M. Sattari, M. H. Zahir, A. A. Allame

    2006-01-01

    Full Text Available Induction of lambda phage carring verotoxin1 gene from a verotoxigenic strains of Escherichia coli and released verotoxin1 were studied under environmental factors of shaking and termperature. Verotoxin1 phage in Escherichia coli PA 101 and transductants was confirmed by bacteriophage detection assay. Shaking of culture media and increasing temperature until 42 ºC increased phage particles in supernatants of Escherichia coli PA 101. Our results indicate that environmental factors such as shaking movements in natural inhabitates of bacteria such as river or sewage streams and temperature rise in summer season could be factors in induce and release free verotoxin1 – producing phage particles in nature that in turn could be the source of phage spreading to other related bacteria , and responsible for increased outbreaks of food borne diseases with verotoxigenic Escherichia coli in warm monthes of year in tropical areas.

  4. Analysis of gene essentiality in Escherichia coli across strains and growth conditions

    DEFF Research Database (Denmark)

    Bonde, Ida; Lennen, Rebecca; Cardoso, Joao

    are either essential or detrimental for growth in the test condition in question. In this study the TN-Seq method was used to investigate the differences in gene essentiality between four laboratory strains of E.coli subjected to four different growth conditions to investigate the reason for the differences...

  5. Complete Genome Sequence of the Avian-Pathogenic Escherichia coli Strain APEC O18.

    Science.gov (United States)

    Nicholson, Bryon A; Wannemuehler, Yvonne M; Logue, Catherine M; Li, Ganwu; Nolan, Lisa K

    2016-11-03

    Avian-pathogenic Escherichia coli (APEC) is the causative agent of colibacillosis, a disease that affects all facets of poultry production worldwide, resulting in multimillion dollar losses annually. Here, we report the genome sequence of an APEC O18 sequence type 95 (ST95) strain associated with disease in a chicken. Copyright © 2016 Nicholson et al.

  6. Evaluation of enterohemorrhagic Escherichia coli (EHEC) growth media against six EHEC strains

    Science.gov (United States)

    Introduction: Food safety specialists continue to be challenged by the need to determine the presence of pathogenic bacteria in foods. This is especially true for E. coli O157:H7 and emerging EHEC strains. Such EHECs survive well in meat and poultry, and although stressed, can remain viable in dry o...

  7. 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...

  8. Genotypic and phenotypic characterisation of Escherichia coli strains associated with porcine pyelonephritis

    DEFF Research Database (Denmark)

    Krag, L.; Hancock, Viktoria; Aalbæk, B.

    2009-01-01

    Urinary tract infection (UTI) is a severe problem in humans as well as in many domestic animals like pigs. The most frequent infectious agent in UTI is uropathogenic Escherichia coli. Such strains have been extensively characterised with respect to virulence and fitness factors as well as clonal...

  9. Fatal necrotizing fasciitis due to necrotic toxin-producing Escherichia coli strain

    Directory of Open Access Journals (Sweden)

    C. Gallois

    2015-11-01

    Full Text Available We report a fatal case of necrotizing soft tissues infection caused by an Escherichia coli strain belonging to phylogenetic group C and harbouring numerous virulence factors reported to be part of a pathogenicity island (PAI such as PAI IIJ96 and conserved virulence plasmidic region.

  10. Shiga Toxin-Producing Serogroup O91 Escherichia coli Strains Isolated from Food and Environmental Samples.

    Science.gov (United States)

    Feng, Peter C H; Delannoy, Sabine; Lacher, David W; Bosilevac, Joseph M; Fach, Patrick; Beutin, Lothar

    2017-09-15

    Shiga toxin-producing Escherichia coli (STEC) strains of the O91:H21 serotype have caused severe infections, including hemolytic-uremic syndrome. Strains of the O91 serogroup have been isolated from food, animals, and the environment worldwide but are not well characterized. We used a microarray and other molecular assays to examine 49 serogroup O91 strains (environmental, food, and clinical strains) for their virulence potential and phylogenetic relationships. Most of the isolates were identified to be strains of the O91:H21 and O91:H14 serotypes, with a few O91:H10 strains and one O91:H9 strain being identified. None of the strains had the eae gene, which codes for the intimin adherence protein, and many did not have some of the genetic markers that are common in other STEC strains. The genetic profiles of the strains within each serotype were similar but differed greatly between strains of different serotypes. The genetic profiles of the O91:H21 strains that we tested were identical or nearly identical to those of the clinical O91:H21 strains that have caused severe diseases. Multilocus sequence typing and clustered regularly interspaced short palindromic repeat analyses showed that the O91:H21 strains clustered within the STEC 1 clonal group but the other O91 serotype strains were phylogenetically diverse. IMPORTANCE This study showed that food and environmental O91:H21 strains have similar genotypic profiles and Shiga toxin subtypes and are phylogenetically related to the O91:H21 strains that have caused hemolytic-uremic syndrome, suggesting that these strains may also have the potential to cause severe illness. Copyright © 2017 American Society for Microbiology.

  11. A draft genome of Escherichia coli sequence type 127 strain 2009-46.

    Science.gov (United States)

    Darling, Aaron E; McKinnon, Jessica; Worden, Paul; Santos, Jerran; Charles, Ian G; Chowdhury, Piklu Roy; Djordjevic, Steven P

    2014-01-01

    Escherichia coli are a frequent cause of urinary tract infections (UTI) and are thought to have a foodborne origin. E. coli with sequence type 127 (ST127) are emerging pathogens increasingly implicated as a cause of urinary tract infections (UTI) globally. A ST127 isolate (2009-46) resistant to ampicillin and trimethoprim was recovered from the urine of a 56 year old patient with a UTI from a hospital in Sydney, Australia and was characterised here. We sequenced the genome of Escherichia coli 2009-46 using the Illumina Nextera XT and MiSeq technologies. Assembly of the sequence data reconstructed a 5.14 Mbp genome in 89 scaffolds with an N50 of 161 kbp. The genome has extensive similarity to other sequenced uropathogenic E. coli genomes, but also has several genes that are potentially related to virulence and pathogenicity that are not present in the reference E. coli strain. E. coli 2009-46 is a multiple antibiotic resistant, phylogroup B2 isolate recovered from a patient with a UTI. This is the first description of a drug resistant E. coli ST127 in Australia.

  12. ORF Sequence: NC_004431 [GENIUS II[Archive

    Lifescience Database Archive (English)

    Full Text Available NC_004431 gi|26249430 >gi|26249430|ref|NP_755470.1| Transposase [Escherichia coli ...CFT073] MPLLDKLREQYGVGPVCSELHIAPSTYYHCQQQRHHPDKRSARAQRDDWLKKEIQRVYDENHQVYGVRKVWRQLLREGIRVARCTVARLMAVMGLAGVLRGKKVRTTSAGKPLLQVTA

  13. Evaluation of Recombinant Attenuated Salmonella Vaccine Strains for Broad Protection against Extraintestinal Pathogenic Escherichia coli

    Directory of Open Access Journals (Sweden)

    Jacob T. Maddux

    2017-10-01

    Full Text Available Antibiotic-resistant bacterial infections are difficult to treat, producing a burden on healthcare and the economy. Extraintestinal pathogenic Escherichia coli (ExPEC strains frequently carry antibiotic resistance genes, cause infections outside of the intestine, and are causative agents of hospital-acquired infections. Developing a prevention strategy against this pathogen is challenging due to its antibiotic resistance and antigenic diversity. E. coli common pilus (ECP is frequently found in ExPEC strains and may serve as a common antigen to induce protection against several ExPEC serotypes. In addition, live recombinant attenuated Salmonella vaccine (RASV strains have been used to prevent Salmonella infection and can also be modified to deliver foreign antigens. Thus, the objective of this study was to design a RASV to produce ECP on its surface and assess its ability to provide protection against ExPEC infections. To constitutively display ECP in a RASV strain, we genetically engineered a vector (pYA4428 containing aspartate-β-semialdehyde dehydrogenase and E. coli ecp genes and introduced it into RASV χ9558. RASV χ9558 containing an empty vector (pYA3337 was used as a control to assess protection conferred by the RASV strain without ECP. We assessed vaccine efficacy in in vitro bacterial inhibition assays and mouse models of ExPEC-associated human infections. We found that RASV χ9558(pYA4428 synthesized the major pilin (EcpA and tip pilus adhesin (EcpD on the bacterial surface. Mice orally vaccinated with RASV χ9558(pYA3337 without ECP or χ9558(pYA4428 with ECP, produced anti-Salmonella LPS and anti-E. coli EcpA and EcpD IgG and IgA antibodies. RASV strains showed protective potential against some E. coli and Salmonella strains as assessed using in vitro assays. In mouse sepsis and urinary tract infection challenge models, both vaccines had significant protection in some internal organs. Overall, this work showed that RASVs can elicit

  14. Characterization of Escherichia coli strains with gapA and gapB genes deleted.

    Science.gov (United States)

    Seta, F D; Boschi-Muller, S; Vignais, M L; Branlant, G

    1997-08-01

    We obtained a series of Escherichia coli strains in which gapA, gapB, or both had been deleted. Delta gapA strains do not revert on glucose, while delta gapB strains grow on glycerol or glucose. We showed that gapB-encoded protein is expressed but at a very low level. Together, these results confirm the essential role for gapA in glycolysis and show that gapB is dispensable for both glycolysis and the pyridoxal biosynthesis pathway.

  15. Characterization of Escherichia coli strains with gapA and gapB genes deleted.

    OpenAIRE

    Seta, F D; Boschi-Muller, S; Vignais, M L; Branlant, G

    1997-01-01

    We obtained a series of Escherichia coli strains in which gapA, gapB, or both had been deleted. Delta gapA strains do not revert on glucose, while delta gapB strains grow on glycerol or glucose. We showed that gapB-encoded protein is expressed but at a very low level. Together, these results confirm the essential role for gapA in glycolysis and show that gapB is dispensable for both glycolysis and the pyridoxal biosynthesis pathway.

  16. Probiotic Escherichia coli strain Nissle 1917 outcompetes intestinal pathogens during biofilm formation

    DEFF Research Database (Denmark)

    Hancock, Viktoria; Dahl, M.; Klemm, Per

    2010-01-01

    Many bacterial infections are associated with biofilm formation. Bacterial biofilms can develop on essentially all kinds of surfaces, producing chronic and often intractable infections. Escherichia coil is an important pathogen causing a wide range of gastrointestinal infections. E. coli strain...... Nissle 1917 has been used for many decades as a probiotic against a variety of intestinal disorders and is probably the best field-tested E. coil strain in the world. Here we have investigated the biofilm-forming capacity of Nissle 1917. We found that the strain was a good biofilm former. Not only...... has a beneficial effect on many intestinal disorders....

  17. Natural Escherichia coli strains undergo cell-to-cell plasmid transformation.

    Science.gov (United States)

    Matsumoto, Akiko; Sekoguchi, Ayuka; Imai, Junko; Kondo, Kumiko; Shibata, Yuka; Maeda, Sumio

    2016-12-02

    Horizontal gene transfer is a strong tool that allows bacteria to adapt to various environments. Although three conventional mechanisms of horizontal gene transfer (transformation, transduction, and conjugation) are well known, new variations of these mechanisms have also been observed. We recently reported that DNase-sensitive cell-to-cell transfer of nonconjugative plasmids occurs between laboratory strains of Escherichia coli in co-culture. We termed this phenomenon "cell-to-cell transformation." In this report, we found that several combinations of Escherichia coli collection of reference (ECOR) strains, which were co-cultured in liquid media, resulted in DNase-sensitive cell-to-cell transfer of antibiotic resistance genes. Plasmid isolation of these new transformants demonstrated cell-to-cell plasmid transfer between the ECOR strains. Natural transformation experiments, using a combination of purified plasmid DNA and the same ECOR strains, revealed that cell-to-cell transformation occurs much more frequently than natural transformation under the same culture conditions. Thus, cell-to-cell transformation is both unique and effective. In conclusion, this study is the first to demonstrate cell-to-cell plasmid transformation in natural E. coli strains. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. Improving Engineered Escherichia coli strains for High-level Biosynthesis of Isobutyrate

    Directory of Open Access Journals (Sweden)

    Mingyong Xiong

    2015-05-01

    Full Text Available Isobutyrate is an important platform chemical with various industrial applications. Previously, a synthetic metabolic pathway was constructed in E. coli to produce isobutyrate from glucose. However, isobutanol was found to be a major byproduct. Herein, gene knockouts and enzyme overexpressions were performed to optimize further the engineered E. coli strain. Besides yqhD, the knockouts of three genes eutG, yiaY and ygjB increased isobutyrate production in shake flasks. Furthermore, the introduction of an additional padA on a medium copy number plasmid under the constitutive promoter significantly reduced isobutanol formation. The IBA15-2C strain (BW25113, DyqhD, DygjB; carrying two copies of padA produced 39.2% more isobutyrate (0.39 g/glucose yield, 80% of the theoretical maximum yield than IBA1-1C strain (BW25113, DyqhD; carrying one copy of padA. A scale-up process was also investigated for IBA15-2C strain to optimize the conditions for the production of isobutyrate in the fermentor. With Ca(OH2 as the base for pH control and 10% dissolved oxygen level, IBA15-2C strain produced 90 g/L isobutyrate after 144 h. This study has engineered E. coli to achieve biosynthesis of a nonnative compound with the highest titer and opened up the possibility of the industrial production of isobutyrate.

  19. A simple and effective method for construction of Escherichia coli strains proficient for genome engineering.

    Science.gov (United States)

    Ryu, Young Shin; Biswas, Rajesh Kumar; Shin, Kwangsu; Parisutham, Vinuselvi; Kim, Suk Min; Lee, Sung Kuk

    2014-01-01

    Multiplex genome engineering is a standalone recombineering tool for large-scale programming and accelerated evolution of cells. However, this advanced genome engineering technique has been limited to use in selected bacterial strains. We developed a simple and effective strain-independent method for effective genome engineering in Escherichia coli. The method involves introducing a suicide plasmid carrying the λ Red recombination system into the mutS gene. The suicide plasmid can be excised from the chromosome via selection in the absence of antibiotics, thus allowing transient inactivation of the mismatch repair system during genome engineering. In addition, we developed another suicide plasmid that enables integration of large DNA fragments into the lacZ genomic locus. These features enable this system to be applied in the exploitation of the benefits of genome engineering in synthetic biology, as well as the metabolic engineering of different strains of E. coli.

  20. High variation of fluorescence protein maturation times in closely related Escherichia coli strains.

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    Elke Hebisch

    Full Text Available Fluorescent proteins (FPs are widely used in biochemistry, biology and biophysics. For quantitative analysis of gene expression FPs are often used as marking molecules. Therefore, sufficient knowledge of maturation times and their affecting factors is of high interest. Here, we investigate the maturation process of the FPs GFP and mCherry expressed by the three closely related Escherichia coli strains of the Colicin E2 system, a model system for colicinogenic interaction. One strain, the C strain produces Colicin, a toxin to which the S strain is sensitive, and against which the R strain is resistant. Under the growth conditions used in this study, the S and R strain have similar growth rates, as opposed to the C strain whose growth rate is significantly reduced due to the toxin production. In combination with theoretical modelling we studied the maturation kinetics of the two FPs in these strains and could confirm an exponential and sigmoidal maturation kinetic for GFP and mCherry, respectively. Our subsequent quantitative experimental analysis revealed a high variance in maturation times independent of the strain studied. In addition, we determined strain dependent maturation times and maturation behaviour. Firstly, FPs expressed by the S and R strain mature on similar average time-scales as opposed to FPs expressed by the C strain. Secondly, dependencies of maturation time with growth conditions are most pronounced in the GFP expressing C strain: Doubling the growth rate of this C strain results in an increased maturation time by a factor of 1.4. As maturation times can vary even between closely related strains, our data emphasize the importance of profound knowledge of individual strains' maturation times for accurate interpretation of gene expression data.

  1. Microarray based comparative genotyping of gentamicin resistant Escherichia coli strains from food animals and humans.

    Science.gov (United States)

    Szmolka, Ama; Anjum, Muna F; La Ragione, Roberto M; Kaszanyitzky, Eva J; Nagy, Béla

    2012-04-23

    Recent data from the European and Hungarian Antimicrobial Resistance Monitoring Systems have indicated that the routine use of gentamicin in human and veterinary medicine frequently leads to the selection of gentamicin resistance in Escherichia coli. The aim of this study was to provide molecular characterization of gentamicin resistance in clinical and commensal E. coli strains representing humans and food producing animals by genotyping for antimicrobial resistance and virulence using a miniaturized microarray. All 50 strains tested proved to be multidrug resistant defined as resistance to three or more antimicrobial classes. Antimicrobial resistances genes such as aadA1-like, strB, bla(TEM), sul1 and tet(A) or tet(B), and corresponding phenotypes (streptomycin-, ampicillin-, sulfamethoxazole- and tetracycline resistance) were detected in >50% of isolates regardless of the host or clinical background. However, certain genes encoding gentamicin resistance such as aac(6')-Ib and ant(2″)-Ia as well as catB3-like genes for phenicol resistance were only detected in human isolates. Among virulence genes, the increased serum survival gene iss was predominant in all host groups. Although the majority of gentamicin resistant E. coli strains were characterized by diverse antimicrobial resistance, and virulence gene patterns, accentuated links between catB3-like, aac(6')-Ib, bla(CTX-M-1) and sat genes could be detected in human strains. Further resistance/virulence gene associations (tet(A) with iroN and iss) were detected in poultry strains. In conclusion, the simultaneous characterization of antimicrobial resistance and virulence genotypes of representative clinical and commensal strains of E. coli should be useful for the identification of emerging genotypes with human and or animal health implications. Copyright © 2011 Elsevier B.V. All rights reserved.

  2. Comparison of detection methods for extended-spectrum beta-lactamases in Escherichia coli strains

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    Ewelina Kałużna

    2014-06-01

    Full Text Available Introduction: Detection of extended-spectrum beta-lactamases (ESBLs could be a major challenge for microbiologists – the difficulties arise mainly from the phenotypic differences among strains.Materials and Methods: Evaluation of ESBLs was performed on 42 strains of E. coli by: 1 DDST on MHA, 2 DDST on MHA with cloxacillin, 3 CT on MHA, according to CLSI, 4 CT on MHA with cloxacillin, 5 Etest ESBL (AB Biodisk, 6 CHROMagarTM ESBL (GRASO, 7 ChromID® ESBL (bioMérieux, and 8 automatic system VITEK2 ESBL test (bioMérieux.Result: Positive results were obtained for 20 strains using method 1, for 18 strains using method 2, 17 by method 3, 14 by method 4, 11 by method 5, 39 by method 6, 40 by method 7, and 15 by method 8. Using Etest ESBL 6.0 non-determinable results were obtained. The most consistent results were obtained when comparing the results of method 3 with results of method 2 (97.6%, and comparing the results obtained using methods 3 and 8 (95.2%.Conclusions: Based on our study we conclude that the chromogenic media can only be used as a screening method for the detection of ESBLs in E. coli rods. Etest is less useful compared to other phenotype methods, due to the impossibility of obtaining results for all the tested strains. Adding cloxacillin to MHA does not increase the frequency of detection of ESBLs in E. coli strains. DDST seems to be the most reliable among phenotypic methods for the detection of ESBLs in E. coli rods.

  3. [Adhesion patterns in diffusely adherent Escherichia coli (DAEC) strains isolated from children with and without diarrhea].

    Science.gov (United States)

    Riveros, Maribel; Barletta, Francesca; Cabello, Martín; Durand, David; Mercado, Erik H; Contreras, Carmen; Rivera, Fulton P; Mosquito, Susan; Lluque, Angela; Ochoa, Theresa J

    2011-03-01

    Diffusely adherent E. coli (DAEC) is the sixth recognized group of diarrheagenic E. coli. However, its association with diarrhea remains controversial. Variability in the adherence patterns of clinical strains is unknown. To compare the adherence patterns between strains isolated from children with and without diarrhea. A total of 31 DAEC strains were analyzed, 25 from children with diarrhea and 6 from asymptomatic (control) children, isolated from a cohort study of children under one year of age in the southern districts of Lima. DAEC were identified by PCR (daaD gene). The pattern and adherence score in HEp-2 cell culture were evaluated, Actin polimerization was determined by fluorescence actin staining (FAS) and motility was evaluated by conventional microbiology methods. Diffuse adherence pattern was found in 88% of diarrhea samples and in the total of control strains. The number of bacteria adhered per cell was significantly lower in diarrhea samples (p<0.05). However, actin polymerization was greater in diarrhea samples (60% vs. 17%). Motility test was positive in 60% of the diarrhea samples and in all control samples. Our findings suggest a difference between adherence patterns, actin polymerization and motility between DAEC strains corresponding to diarrhea and control groups. The significance of these results must be confirmed with a bigger number of strains and determining the presence of virulence genes in the strains.

  4. Whole-Genome Characterization and Strain Comparison of VT2f-Producing Escherichia coli Causing Hemolytic Uremic Syndrome

    Science.gov (United States)

    Michelacci, Valeria; Bondì, Roslen; Gigliucci, Federica; Franz, Eelco; Badouei, Mahdi Askari; Schlager, Sabine; Minelli, Fabio; Tozzoli, Rosangela; Caprioli, Alfredo; Morabito, Stefano

    2016-01-01

    Verotoxigenic Escherichia coli infections in humans cause disease ranging from uncomplicated intestinal illnesses to bloody diarrhea and systemic sequelae, such as hemolytic uremic syndrome (HUS). Previous research indicated that pigeons may be a reservoir for a population of verotoxigenic E. coli producing the VT2f variant. We used whole-genome sequencing to characterize a set of VT2f-producing E. coli strains from human patients with diarrhea or HUS and from healthy pigeons. We describe a phage conveying the vtx2f genes and provide evidence that the strains causing milder diarrheal disease may be transmitted to humans from pigeons. The strains causing HUS could derive from VT2f phage acquisition by E. coli strains with a virulence genes asset resembling that of typical HUS-associated verotoxigenic E. coli. PMID:27584691

  5. Comparative sequence analysis of enteroaggregative Escherichia coli heat-stable enterotoxin 1 identified in Korean and Japanese Escherichia coli strains.

    Science.gov (United States)

    Seo, Dong Joo; Choi, SunKeum; Jeon, Su Been; Jeong, Suntak; Park, Hyunkyung; Lee, Bog-Hieu; Kim, Geun-Bae; Yang, Soo-Jin; Nishikawa, Yoshikazu; Choi, Changsun

    2017-02-21

    The aim of this study was to compare the sequence of the astA gene found in 8 Korean and 11 Japanese Escherichia coli isolates. Conventional PCR was used to amplify the astA gene from the chromosomal and plasmid DNA preparation samples of each isolate using commercial DNA extraction kits. Cloning of the PCR products, sequence analysis, and pulse field gel electrophoresis (PFGE) were sequentially performed. An identical copy of astA in each isolate were found for 8 Korean and 8 Japanese E. coli strains isolated from bovine, porcine, and healthy human carriers. Among these, 1 Korean and 4 Japanese isolates carried a stop mutation at residue 16. Three Japanese outbreak strains (V199, V638, and 96-127-23) carried multiple clones of astA gene with multiple amino acids changes at residues 11, 16, 20, 23, 30, 33, and 34. Compared with the non-diarrheal isolates, clonal diversity and sequence variations of the astA gene in outbreak isolates may be associated with virulence potential of EAST1. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Comparative Study of Various E. coli Strains for Biohydrogen Production Applying Response Surface Methodology

    Science.gov (United States)

    Bakonyi, Péter; Nemestóthy, Nándor; Bélafi-Bakó, Katalin

    2012-01-01

    The proper strategy to establish efficient hydrogen-producing biosystems is the biochemical, physiological characterization of hydrogen-producing microbes followed by metabolic engineering in order to give extraordinary properties to the strains and, finally, bioprocess optimization to realize enhanced hydrogen fermentation capability. In present paper, it was aimed to show the utility both of strain engineering and process optimization through a comparative study of wild-type and genetically modified E. coli strains, where the effect of two major operational factors (substrate concentration and pH) on bioH2 production was investigated by experimental design and response surface methodology (RSM) was used to determine the suitable conditions in order to obtain maximum yields. The results revealed that by employing the genetically engineered E. coli (DJT 135) strain under optimized conditions (pH: 6.5; Formate conc.: 1.25 g/L), 0.63 mol H2/mol formate could be attained, which was 1.5 times higher compared to the wild-type E. coli (XL1-BLUE) that produced 0.42 mol H2/mol formate (pH: 6.4; Formate conc.: 1.3 g/L). PMID:22666156

  7. Comparative Study of Various E. coli Strains for Biohydrogen Production Applying Response Surface Methodology

    Directory of Open Access Journals (Sweden)

    Péter Bakonyi

    2012-01-01

    Full Text Available The proper strategy to establish efficient hydrogen-producing biosystems is the biochemical, physiological characterization of hydrogen-producing microbes followed by metabolic engineering in order to give extraordinary properties to the strains and, finally, bioprocess optimization to realize enhanced hydrogen fermentation capability. In present paper, it was aimed to show the utility both of strain engineering and process optimization through a comparative study of wild-type and genetically modified E. coli strains, where the effect of two major operational factors (substrate concentration and pH on bioH2 production was investigated by experimental design and response surface methodology (RSM was used to determine the suitable conditions in order to obtain maximum yields. The results revealed that by employing the genetically engineered E. coli (DJT 135 strain under optimized conditions (pH: 6.5; Formate conc.: 1.25 g/L, 0.63 mol H2/mol formate could be attained, which was 1.5 times higher compared to the wild-type E. coli (XL1-BLUE that produced 0.42 mol H2/mol formate (pH: 6.4; Formate conc.: 1.3 g/L.

  8. Colistin Resistance in Escherichia coli and Salmonella enterica Strains Isolated from Swine in Brazil

    Directory of Open Access Journals (Sweden)

    Adriano Savoia Morales

    2012-01-01

    Full Text Available Reports about acquired resistance to colistin in different bacteria species are increasing, including E. coli of animal origin, but reports of resistance in wild S. enterica of different serotypes from swine are not found in the literature. Results obtained with one hundred and twenty-six E. coli strains from diseased swine and one hundred and twenty-four S. enterica strains from diseased and carrier swine showed a frequency of 6.3% and 21% of colistin-resistant strains, respectively. When comparing the disk diffusion test with the agar dilution test to evaluate the strains, it was confirmed that the disk diffusion test is not recommended to evaluate colistin resistance as described previously. The colistin MIC 90 and MIC 50 values obtained to E. coli were 0.25 μg/mL and 0.5 μg/mL, the MIC 90 and MIC 50 to S. enterica were 1 μg/mL and 8 μg/mL. Considering the importance of colistin in control of nosocomial human infections with Gram-negative multiresistant bacteria, and the large use of this drug in animal production, the colistin resistance prevalence in enterobacteriaceae of animal origin must be monitored more closely.

  9. Infections with Avian Pathogenic and Fecal Escherichia coli Strains Display Similar Lung Histopathology and Macrophage Apoptosis

    Science.gov (United States)

    Horn, Fabiana; Corrêa, André Mendes Ribeiro; Barbieri, Nicolle Lima; Glodde, Susanne; Weyrauch, Karl Dietrich; Kaspers, Bernd; Driemeier, David; Ewers, Christa; Wieler, Lothar H.

    2012-01-01

    The purpose of this study was to compare histopathological changes in the lungs of chickens infected with avian pathogenic (APEC) and avian fecal (Afecal) Escherichia coli strains, and to analyze how the interaction of the bacteria with avian macrophages relates to the outcome of the infection. Chickens were infected intratracheally with three APEC strains, MT78, IMT5155, and UEL17, and one non-pathogenic Afecal strain, IMT5104. The pathogenicity of the strains was assessed by isolating bacteria from lungs, kidneys, and spleens at 24 h post-infection (p.i.). Lungs were examined for histopathological changes at 12, 18, and 24 h p.i. Serial lung sections were stained with hematoxylin and eosin (HE), terminal deoxynucleotidyl dUTP nick end labeling (TUNEL) for detection of apoptotic cells, and an anti-O2 antibody for detection of MT78 and IMT5155. UEL17 and IMT5104 did not cause systemic infections and the extents of lung colonization were two orders of magnitude lower than for the septicemic strains MT78 and IMT5155, yet all four strains caused the same extent of inflammation in the lungs. The inflammation was localized; there were some congested areas next to unaffected areas. Only the inflamed regions became labeled with anti-O2 antibody. TUNEL labeling revealed the presence of apoptotic cells at 12 h p.i in the inflamed regions only, and before any necrotic foci could be seen. The TUNEL-positive cells were very likely dying heterophils, as evidenced by the purulent inflammation. Some of the dying cells observed in avian lungs in situ may also be macrophages, since all four avian E. coli induced caspase 3/7 activation in monolayers of HD11 avian macrophages. In summary, both pathogenic and non-pathogenic fecal strains of avian E. coli produce focal infections in the avian lung, and these are accompanied by inflammation and cell death in the infected areas. PMID:22848424

  10. Diffusely adherent Escherichia coli strains isolated from children and adults constitute two different populations

    Directory of Open Access Journals (Sweden)

    Mansan-Almeida Rosane

    2013-02-01

    Full Text Available Abstract Background Diffusely adherent Escherichia coli (DAEC have been considered a diarrheagenic category of E. coli for which several potential virulence factors have been described in the last few years. Despite this, epidemiological studies involving DAEC have shown inconsistent results. In this work, two different collections of DAEC possessing Afa/Dr genes, from children and adults, were studied regarding characteristics potentially associated to virulence. Results DAEC strains were recovered in similar frequencies from diarrheic and asymptomatic children, and more frequently from adults with diarrhea (P Citrobacter freundii strain have shown an improved ability to form biofilms in relation to the monocultures. Control strains have shown a greater diversity of Afa/Dr adhesins and higher frequencies of cellulose, TTSS, biofilm formation and induction of IL-8 secretion than strains from cases of diarrhea in children. Conclusions DAEC strains possessing Afa/Dr genes isolated from children and adults represent two different bacterial populations. DAEC strains carrying genes associated to virulence can be found as part of the normal microbiota present in asymptomatic children.

  11. 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

  12. 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.

  13. ANTIMICROBIAL DRUG RESISTANCE IN STRAINS OF Escherichia coli ISOLATED FROM FOOD SOURCES

    Directory of Open Access Journals (Sweden)

    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.

  14. The expression of lipopolysaccharide by strains of Shigella dysenteriae, Shigella flexneri and Shigella boydii and their cross-reacting strains of Escherichia coli.

    Science.gov (United States)

    Chart, Henrik; Daniel, Roger M A; Cheasty, Thomas

    2009-03-01

    Strains of Shigella dysenteriae, Shigella flexneri and Shigella boydii express lipopolysaccharides, that enable the serotyping of strains based on their antigenic structures. Certain strains of S. dysenteriae, S. flexneri and S. boydii are known to share epitopes with strains of Escherichia coli; however, the lipopolysaccharide profiles of the cross-reacting organisms have not been compared by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) lipopolysaccharides profiling. In the present study, type strains of these bacteria were examined using SDS-PAGE/silver staining to compare their respective lipopolysaccharide profiles. Strains of S. dysenteriae, S. boydii and S. flexneri all expressed long-chain lipopolysaccharide, with distinct profile patterns. The majority of strains of Shigella spp., known to cross-react with strains of E. coli, had lipopolysaccharide profiles quite distinct from the respective strain of E. coli. It was concluded that while cross-reacting strains of Shigella spp. and E. coli may express shared lipopolysaccharide epitopes, their lipopolysaccharide structures are not identical.

  15. Multirresistência antimicrobiana em cepas de Escherichia coli isoladas de cadelas com piometra Antimicrobial multi-resistance of Escherichia coli strains isolated from bitches with pyometra

    Directory of Open Access Journals (Sweden)

    V.M. Lara

    2008-08-01

    Full Text Available The antimicrobial sensibility of Escherichia coli strains isolated from the uterine content of bitches was evaluated. Fifteen E. coli strains were tested in relation to their susceptibility to different antimicrobials. The results demonstrated 100% of resistance to all tested drugs, being a quite conflicting finding compared to other works, which observed variable resistance of those bacteria to different antimicrobials but not the same multi-resistance pattern. The detection of those multi-resistance strains configures a problem, with important implications on the antimicrobial therapy. Therefore, additional investigations for a best characterization and extension of this problem are needed.

  16. Molecular typing of Escherichia coli strains isolated from food in Casablanca (Morocco).

    Science.gov (United States)

    Badri, S; Fassouane, A; Filliol, I; Hassar, M; Cohen, N

    2009-06-15

    Serotyping of O- and H- antigens is regarded as the gold standard in classification of E. coli for taxonomic and epidemiological purposes similar to the Kaufmann-White scheme for Salmonella enterica. Molecular methods to replace or to support the serotyping were recently applied. Using the molecular polymorphism of the somatic (O- antigen) gene rfb cluster and flagella (H- antigen) gene fliC, 74 E. coli strains carrying the virulent genes isolated from food were characterised by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The results showed that 49 (66%) of the isolates revealed a reproducible and clear cut classification, with a very good correlation to the collection of reference strains, were found.

  17. Comparison of adhesin genes and antimicrobial susceptibilities between uropathogenic and intestinal commensal Escherichia coli strains.

    Science.gov (United States)

    Qin, Xiaohua; Hu, Fupin; Wu, Shi; Ye, Xinyu; Zhu, Demei; Zhang, Ying; Wang, Minggui

    2013-01-01

    The presence of adhesins is arguably an important determinant of pathogenicity for Uropathogenic Escherichia coli (UPEC). Antimicrobial susceptibilities were tested by agar dilution method, fifteen adhesin genes were detected by polymerase chain reaction, and multilocus sequence typing (MLST) was analyzed in 70 UPEC isolates and 41 commensal E. coli strains. Extended-spectrum β-lactamase (ESBL) was determined with confirmatory test. The prevalence of ESBL-producers in UPEC (53%, 37/70) was higher than the commensal intestinal isolates (7%, 3/41), and 97% (36/37) of the ESBL-producing UPEC harbored bla CTX-M genes. afa was present in 36% (10/28) UPEC isolates from recurrent lower urinary tract infection (UTI), and none in the acute pyelonephritis, acute uncomplicated cystitis or commensal strains (Pcoli, and afa may be associated with recurrent lower UTI whereas papG is more frequently associated with acute pyelonephritis.

  18. Biotin-independent strains of Escherichia coli for enhanced streptavidin production.

    Science.gov (United States)

    Jeschek, Markus; Bahls, Maximilian O; Schneider, Veronika; Marlière, Philippe; Ward, Thomas R; Panke, Sven

    2017-03-01

    Biotin is an archetypal vitamin used as cofactor for carboxylation reactions found in all forms of life. However, biotin biosynthesis is an elaborate multi-enzymatic process and metabolically costly. Moreover, many industrially relevant organisms are incapable of biotin synthesis resulting in the requirement to supplement defined media. Here we describe the creation of biotin-independent strains of Escherichia coli and Corynebacterium glutamicum through installation of an optimized malonyl-CoA bypass, which re-routes natural fatty acid synthesis, rendering the previously essential vitamin completely obsolete. We utilize biotin-independent E. coli for the production of the high-value protein streptavidin which was hitherto restricted because of toxic effects due to biotin depletion. The engineered strain revealed significantly improved streptavidin production resulting in the highest titers and productivities reported for this protein to date. Copyright © 2017 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

  19. Antibioresistance of Escherichia coli Strains Isolated from Chicken Colibacillosis in Western Algeria

    OpenAIRE

    HAMMOUDI, Abdelhamid; AGGAD, Hebib

    2014-01-01

    In western Algeria, 251 Escherichia coli isolates were recovered from broilers with clinical signs and lesions of colibacillosis. Serotyping showed that 82% of the isolates belong to one of the following serotypes: O78, O2, and O1. Antibiograms revealed a high level of resistance to oxytetracycline (82%), amoxicilline and ampicilline (47%), trimethoprim-sulfmethoxazole (42%), oxolinic acid and flumequine (31%). However, only a low percentage of strains were resistant to enrofloxacine (6%) and...

  20. Development of a genetically engineered Escherichia coli strain for plasmid transformation in Corynebacterium glutamicum.

    Science.gov (United States)

    Li, Hedan; Zhang, Lirong; Guo, Wei; Xu, Daqing

    2016-12-01

    Gene disruption and replacement in Corynebacterium glutamicum is dependent upon a high transformation efficiency. The cglIR-cgIIR restriction system is a major barrier to introduction of foreign DNA into Corynebacterium glutamicum cells. To improve the transformation efficiency of C. glutamicum, the cglIM gene encoding methyltransferase in the cglIR-cglIIR-cglIM restriction-modification system of C. glutamicum ATCC 13032 was chromosomally integrated and expressed in Escherichia coli, resulting in an engineered strain E. coli AU1. The electro-transformation experiments of C. glutamicum ATCC 13032 with the E. coli-C. glutamicum shuttle plasmid pAU4 showed that the transformation efficiency of C. glutamicum with pAU4 DNA extracted from E. coli TG1/pAU4 was 1.80±0.21×10 2 cfu/μg plasmid DNA, while using pAU4 DNA extracted from E. coli AU1/pAU4, the transformation efficiency reached up to 5.22±0.33×10 6 cfu/μg plasmid DNA. The results demonstrated that E. coli AU1 is able to confer the cglIM-specific DNA methylation pattern to its resident plasmid, which makes the plasmid resistant to the cglIR-cglIIR restriction and efficiently transferred into C. glutamicum. E. coli AU1 is a useful intermediate host for efficient transformation of C. glutamicum. Copyright © 2016. Published by Elsevier B.V.

  1. In Silico Signature Prediction Modeling in Cytolethal Distending Toxin-Producing Escherichia coli Strains.

    Science.gov (United States)

    Javadi, Maryam; Oloomi, Mana; Bouzari, Saeid

    2017-06-01

    In this study, cytolethal distending toxin (CDT) producer isolates genome were compared with genome of pathogenic and commensal Escherichia coli strains. Conserved genomic signatures among different types of CDT producer E. coli strains were assessed. It was shown that they could be used as biomarkers for research purposes and clinical diagnosis by polymerase chain reaction, or in vaccine development. cdt genes and several other genetic biomarkers were identified as signature sequences in CDT producer strains. The identified signatures include several individual phage proteins (holins, nucleases, and terminases, and transferases) and multiple members of different protein families (the lambda family, phage-integrase family, phage-tail tape protein family, putative membrane proteins, regulatory proteins, restriction-modification system proteins, tail fiber-assembly proteins, base plate-assembly proteins, and other prophage tail-related proteins). In this study, a sporadic phylogenic pattern was demonstrated in the CDT-producing strains. In conclusion, conserved signature proteins in a wide range of pathogenic bacterial strains can potentially be used in modern vaccine-design strategies.

  2. Flooding adds pathogenic Escherichia coli strains to the water sources in southern Khyber Pakhtunkhwa, Pakistan

    Directory of Open Access Journals (Sweden)

    M S Shah

    2016-01-01

    Full Text Available Purpose: Seasonal rains in Pakistan result in heavy floods across the country, whereby faecal contaminants will be added to the water bodies and cause numerous food-borne outbreaks. The present study was aimed to determine the prevalence of diarrheagenic Escherichia coli (DEC strains in the water sources. Materials and Methods: Two hundred water samples collected during (2011–2012 were processed for the isolation of E. coli (EC strains. EC strains were further analysed for antibiotic susceptibility patterns, and pathogroups-specific virulence factors stx1, stx2, stx2c, eae, tir, hlyA, bfpA, estA and eltA were detected using multiplex polymerase chain reaction. Results: Thirty-three percent of the water samples were contaminated with EC pathotypes. Fifty percent (33/66 of the DEC pathotypes were identified as enterotoxigenic EC (ETEC. Seventy-two percent (13/18 of the enteropathogenic EC (EPEC strains were identified as typical EPEC and 28% (5/18 as atypical EPEC. Eleven percent (7/66 of the Shiga toxin EC (STEC isolates carried a combination of stx1 and stx2 genes. Summer was found as a peak season with 47% (31/66 for EC pathogroups' activities. Eighty-nine percent of the strains showed resistance against tetracycline. Conclusion: ETEC and EPEC are the primary causes of water contamination in southern regions of Khyber Pakhtunkhwa province, Pakistan. Firm adherence to the prescribed drugs can decrease trends in antibiotic resistance.

  3. Adherence, enterotoxigenicity, invasiveness and serogroups in Campylobacter jejuni and Campylobacter coli strains from adult humans with acute enterocolitis.

    Science.gov (United States)

    Lindblom, G B; Cervantes, L E; Sjögren, E; Kaijser, B; Ruiz-Palacios, G M

    1990-02-01

    Two hundred Campylobacter jejuni and Campylobacter coli strains from the same number of adult Swedish patients with acute enterocolitis were tested regarding adherence to and invasiveness in HEp-2 cells and for enterotoxigenicity by the CHO-cell assay. The serogroup characteristics, heat-stable and heat-labile, for each strain were also investigated. Eighty-four percent of the strains were classified as C. jejuni and 16 percent as C. coli. All of the strains were adherent to HEp-2 cells, 39% were invasive and 31.5% enterotoxigenic. We found significantly more invasive strains in the non-enterotoxigenic group than in the enterotoxigenic one. There would seem to be no correlation between enterotoxigenicity or invasiveness and serogroup. The results of this study suggest the existence of multiple mechanisms for C. jejuni- and C. coli-induced diarrhoea and that the mechanisms may differ from one strain to another.

  4. Modeling the growth dynamics of multiple Escherichia coli strains in the pig intestine following intramuscular ampicillin treatment

    DEFF Research Database (Denmark)

    Ahmad, Amais; Zachariasen, Camilla; Christiansen, Lasse Engbo

    2016-01-01

    Background : This study evaluated how dosing regimen for intramuscularly-administered ampicillin, composition of Escherichia coli strains with regard to ampicillin susceptibility, and excretion of bacteria from the intestine affected the level of resistance among Escherichia coli strains...... in the intestine of nursery pigs. It also examined the dynamics of the composition of bacterial strains during and after the treatment. The growth responses of strains to ampicillin concentrations were determined using in vitro growth curves. Using these results as input data, growth predictions were generated...... using a mathematical model to simulate the competitive growth of E. coli strains in a pig intestine under specified plasma concentration profiles of ampicillin. Results : In vitro growth results demonstrated that the resistant strains did not carry a fitness cost for their resistance, and that the most...

  5. Detection of Enterohemorrhagic Escherichia coli Related Genes in E. coli Strains Belonging to B2 Phylogroup Isolated from Urinary Tract Infections in Combination with Antimicrobial Resistance Phenotypes

    Directory of Open Access Journals (Sweden)

    Hamid Staji

    2017-07-01

    Full Text Available Background:  This study was conducted to detect the prevalence of EHEC virulence genes and antimicrobial resistance profile of Escherichia coli strains belonging to B2 phylogroup implicated in Urinary tract infections in Semnan, Iran.Methods:   From 240 urine samples 160 E. coli strains were isolated, biochemically. Then, E. coli isolates were examined by Multiplex-PCR for phylogenetic typing and detection of virulence genes (hly, stx1, stx2, eae associated with Enterohemorrhagic E. coli. Finally, Antimicrobial resistance of E. coli isolates were characterized using Disk Diffusion method.  Results:  From 160 E. coli isolates, 75 strains (47% were assigned to B2 phylogenetic group and prevalence of virulence genes were as follow: hly (21.3%, stx1 (16%, stx2 (10.6% and eae (6.7%, subsequently.  Phenotypic antimicrobial resistance of B2 isolates showed that all isolates were sensitive to Meropenem and Furazolidone and then highest frequency of resistance was observed to Streptomycin, Oxytetracycline, Neomycin, Nalidixic acid and Ampicillin (98.7% to 49.3%. Also low resistance prevalence was observed in case of Ceftizoxime, Lincospectin, Imipenem, Chloramphenicol and flurefenicole (16% to 1.3%.Conclusion:   The data suggest a high prevalence of antibiotic resistance in UPEC strains belonging to B2 phylogroup even for the antimicrobials using in pet and farm animals and their potential to cause EHEC specific clinical symptoms which may represent a serious health risk since these strains can be transmitted to GI tract and act as a reservoir for other uropathogenic E. coli and commensal strains.

  6. Genome assembly of E. coli KV7, a BLA-CTX-containing strain isolated from a pig

    NARCIS (Netherlands)

    Bateman, Michael D.; Vries, de S.P.W.; Gupta, Srishti; Guardabassi, Luca; Cavaco, Lina M.; Grant, Andrew J.; Holmes, Mark A.

    1800-01-01

    We report the chromosome and plasmid sequences of a spontaneous nalidixic acid resistant derivative of the ESBL-producing E. coli strain KV7. E. coli KV7 was originally isolated from a healthy pig that was treated prophylactically with ceftiofur. KV7 belongs to serotype O27 and phylogenetic group D,

  7. IMPACT OF DIFFERENT ENVIRONMENTAL PARAMETERS UPON THE SUSCEPTIBILITY TO HEAVY METALS SALTS IN ESCHERICHIA COLI AQUATIC STRAINS

    OpenAIRE

    Emilia Panus; Mariana Carmen Chifiriuc; Coralia Bleotu; Magda Mitache; Natalia Rosoiu

    2012-01-01

    Purpose: to investigate the relationships among the expression of susceptibility to heavy metal salts, different incubation temperatures and chemical composition of the culture media in E. coli aquatic strains. 100 strains of E. coli isolated from Black Sea were investigated for the expression of resistance to different bivalent metals (Cu, Co, Mn, Zn, Ni) compounds. The experiments were performed comparatively at different incubation temperatures (22°C, 37°C and 44°C) in aerobic and anaerobi...

  8. Metabolic engineering of a reduced-genome strain of Escherichia coli for L-threonine production

    Directory of Open Access Journals (Sweden)

    Yoon Byoung

    2009-01-01

    Full Text Available Abstract Background Deletion of large blocks of nonessential genes that are not needed for metabolic pathways of interest can reduce the production of unwanted by-products, increase genome stability, and streamline metabolism without physiological compromise. Researchers have recently constructed a reduced-genome Escherichia coli strain MDS42 that lacks 14.3% of its chromosome. Results Here we describe the reengineering of the MDS42 genome to increase the production of the essential amino acid L-threonine. To this end, we over-expressed a feedback-resistant threonine operon (thrA*BC, deleted the genes that encode threonine dehydrogenase (tdh and threonine transporters (tdcC and sstT, and introduced a mutant threonine exporter (rhtA23 in MDS42. The resulting strain, MDS-205, shows an ~83% increase in L-threonine production when cells are grown by flask fermentation, compared to a wild-type E. coli strain MG1655 engineered with the same threonine-specific modifications described above. And transcriptional analysis revealed the effect of the deletion of non-essential genes on the central metabolism and threonine pathways in MDS-205. Conclusion This result demonstrates that the elimination of genes unnecessary for cell growth can increase the productivity of an industrial strain, most likely by reducing the metabolic burden and improving the metabolic efficiency of cells.

  9. Evidence of horizontal gene transfer between human and animal commensal Escherichia coli strains identified by microarray.

    Science.gov (United States)

    Grasselli, Elena; François, Patrice; Gutacker, Michaela; Gettler, Brian; Benagli, Cinzia; Convert, Maruska; Boerlin, Patrick; Schrenzel, Jacques; Piffaretti, Jean-Claude

    2008-08-01

    Bacteria exchange genetic material by horizontal gene transfer (HGT). To evaluate the impact of HGT on Escherichia coli genome plasticity, 19 commensal strains collected from the intestinal floras of humans and animals were analyzed by microarrays. Strains were hybridized against an oligoarray containing 2700 E. coli K12 chromosomal genes. A core (genes shared among compared genomes) and a flexible gene pool (genes unique for each genome) have been identified. Analysis of hybridization signals evidenced 1015 divergent genes among the 19 strains and each strain showed a specific genomic variability pattern. Four hundred and fifty-eight genes were characterized by higher rates of interstrain variation and were considered hyperdivergent. These genes are not randomly distributed onto the chromosome but are clustered in precise regions. Hyperdivergent genes belong to the flexible gene pool and show a specific GC content, differing from that of the chromosome, indicating acquisition by HGT. Among these genes, those involved in defense mechanisms and cell motility as well as intracellular trafficking and secretion were far more represented than others. The observed genome plasticity contributes to the maintenance of genetic diversity and may therefore be a source of evolutionary adaptation and survival.

  10. Indigenous plasmids in a production line of strains for penicillin G acylase derived from Escherichia coli W.

    Science.gov (United States)

    Sobotková, L; Grafková, J; Stĕpánek, V; Vacík, T; Maresová, H; Kyslík, P

    1999-01-01

    Three indigenous plasmids designated pRK1, pRK2 and pRK3 were identified among producers of penicillin G acylase (PGA) derived from the strain Escherichia coli W ATCC 9637. Their size and copy number (CN) in E. coli W were determined (kb; CN): pRK1 (80; 3.4), pRK2 (5.1; 71), and pRK3 (4.8; 13.7). Strain E. coli RE2 harboring these plasmids was used for selection of strains with reduced number of plasmids: the strain RE3 without plasmid pRK1 and the plasmid-less strain cERE3 were isolated. Indigenous plasmids did not code for the resistance determinants against 23 antibiotics and 10 heavy metals.

  11. ESTIMATION OF SENSITIVENESS TO ANTIMICROBIAL PREPARATIONS OF CLINICAL STRAINS OF ESСHERICHIA COLI

    Directory of Open Access Journals (Sweden)

    Voyda Y. V

    2014-06-01

    Full Text Available High prevalence of drug-resistance among the isolates – representatives of normal microflora is set which does them the potential source of distribution of determinants of drug-resistance among population of this species and family species of bacteria of different taxonomical groups. The high sensitiveness of strains of E. coli to imipenem, gatifloxacin and amikacin is set, that determines their practical value as preparations of reserve for treatment of infections caused by strains with multidrug-resistance. It is found out the growth of resistance to fluoroquinolones and circulation of generous amount mildly proof strains to the nitroxolinum and derivatives of nitrofuran, which occupy a leading place in the charts of the empiric therapy of patients by the chronic infections of urinoexcretory ways.

  12. [Alpha-hemolytic strains of Escherichia coli isolated in urinary tract infections in small children].

    Science.gov (United States)

    Durovicová, J; Puzová, H; Janigová, V; Nistiar, F; Kmetová, M

    1992-04-01

    The authors focused attention on testing of biological properties of alpha-haemolytic strains of E. coli in infections of the urinary pathways in children and on the antibody response against alpha-haemolysin. The strains belonged into serogroups 02, 04, 06, 018, 075, 0112. The majority of strains had fimrial adhesins, i.e. P fimbriae, or fimbriae type 1. Alpha-haemolysin one of the factors of UPEC virulence induces anti-alphahaemolysin formation in serum (ANTI AH). Titres of ANTI AH in sera of children with acute uroinfection were from 1:32 to 1:1024. Lower titres were recorded in infections of the lower urinary pathways higher ones in renal infections, whereby the dynamics of ANTI AH titres depend on the development of the disease.

  13. A versatile Escherichia coli strain for identification of biotin transporters and for biotin quantification.

    Science.gov (United States)

    Finkenwirth, Friedrich; Kirsch, Franziska; Eitinger, Thomas

    2014-01-01

    Biotin is an essential cofactor of carboxylase enzymes in all kingdoms of life. The vitamin is produced by many prokaryotes, certain fungi, and plants. Animals depend on biotin uptake from their diet and in humans lack of the vitamin is associated with serious disorders. Many aspects of biotin metabolism, uptake, and intracellular transport remain to be elucidated. In order to characterize the activity of novel biotin transporters by a sensitive assay, an Escherichia coli strain lacking both biotin synthesis and its endogenous high-affinity biotin importer was constructed. This strain requires artificially high biotin concentrations for growth. When only trace levels of biotin are available, it is viable only if equipped with a heterologous high-affinity biotin transporter. This feature was used to ascribe transport activity to members of the BioY protein family in previous work. Here we show that this strain together with its parent is also useful as a diagnostic tool for wide-concentration-range bioassays.

  14. Chicken Meat as a Reservoir of Colistin-Resistant Escherichia coli Strains Carrying mcr-1 Genes in South America.

    Science.gov (United States)

    Monte, Daniel Farias; Mem, Andressa; Fernandes, Miriam R; Cerdeira, Louise; Esposito, Fernanda; Galvão, Julia A; Franco, Bernadette D G M; Lincopan, Nilton; Landgraf, Mariza

    2017-05-01

    The detection and rapid spread of colistin-resistant Enterobacteriaceae carrying the mcr-1 gene has created an urgent need to strengthen surveillance. In this study, eight clonally unrelated colistin-resistant Escherichia coli isolates carrying mcr-1 and blaCTX-M or blaCMY-2 genes were isolated from commercial chicken meat in Brazil. Most E. coli strains carried IncX4 plasmids, previously identified in human and animal isolates. These results highlight a new reservoir of mcr-1-harboring E. coli strains in South America. Copyright © 2017 American Society for Microbiology.

  15. Antimicrobial-resistant patterns of Escherichia coli and Salmonella strains in the aquatic Lebanese environments

    Energy Technology Data Exchange (ETDEWEB)

    Harakeh, Steve [Department of Biology, American University of Beirut, P.O. Box 11-0236, Beirut (Lebanon)]. E-mail: sharakeh@gmail.com; Yassine, Hadi [Department of Biology, American University of Beirut, P.O. Box 11-0236, Beirut (Lebanon); El-Fadel, Mutasem [Department of Civil and Environmental Engineering, American University of Beirut, P.O. Box 11-0236, Beirut (Lebanon)

    2006-09-15

    This study is the first to be conducted in Lebanon on the isolation and molecular characterization and the antimicrobial resistance profile of environmental pathogenic bacterial strains. Fifty-seven samples of seawater, sediment, crab, and fresh water were collected during the spring and summer seasons of 2003. The isolation of Escherichia coli and Salmonella using appropriate selective media revealed that 94.7% of the tested samples were contaminated with one or both of the tested bacteria. The polymerase chain reaction (PCR) was then used to identify the species of both bacteria using various sets of primers. Many pathogenic E. coli isolates were detected by PCR out of which two were identified as O157:H7 E. coli. Similarly, the species of many of the Salmonella isolates was molecularly identified. The confirmed isolates of Salmonella and E. coli were then tested using the disk diffusion method for their susceptibility to four different antimicrobials revealing high rates of antimicrobial resistance. - First report of antibiotic resistance in bacteria in the environment in Lebanon.

  16. Unexpected phytostimulatory behavior for Escherichia coli and Agrobacterium tumefaciens model strains.

    Science.gov (United States)

    Walker, Vincent; Bruto, Maxime; Bellvert, Floriant; Bally, René; Muller, Daniel; Prigent-Combaret, Claire; Moënne-Loccoz, Yvan; Comte, Gilles

    2013-05-01

    Plant-beneficial effects of bacteria are often underestimated, especially for well-studied strains associated with pathogenicity or originating from other environments. We assessed the impact of seed inoculation with the emblematic bacterial models Agrobacterium tumefaciens C58 (plasmid-cured) or Escherichia coli K-12 on maize seedlings in nonsterile soil. Compared with the noninoculated control, root biomass (with A. tumefaciens or E. coli) and shoot biomass (with A. tumefaciens) were enhanced at 10 days for 'PR37Y15' but not 'DK315', as found with the phytostimulator Azospirillum brasilense UAP-154 (positive control). In roots as well as in shoots, Agrobacterium tumefaciens and E. coli triggered similar (in PR37Y15) or different (in DK315) changes in the high-performance liquid chromatography profiles of secondary metabolites (especially benzoxazinoids), distinct from those of Azospirillum brasilense UAP-154. Genome sequence analysis revealed homologs of nitrite reductase genes nirK and nirBD and siderophore synthesis genes for Agrobacterium tumefaciens, as well as homologs of nitrite reductase genes nirBD and phosphatase genes phoA and appA in E. coli, whose contribution to phytostimulation will require experimental assessment. In conclusion, the two emblematic bacterial models had a systemic impact on maize secondary metabolism and resulted in unexpected phytostimulation of seedlings in the Azospirillum sp.-responsive cultivar.

  17. Detection of Shiga Toxin-Producing Escherichia coli from Nonhuman Sources and Strain Typing.

    Science.gov (United States)

    Beutin, Lothar; Fach, Patrick

    2014-06-01

    Shiga toxin-producing Escherichia coli (STEC) strains are commonly found in the intestine of ruminant species of wild and domestic animals. Excretion of STEC with animal feces results in a broad contamination of food and the environment. Humans get infected with STEC through ingestion of contaminated food, by contact with the environment, and from STEC-excreting animals and humans. STEC strains can behave as human pathogens, and some of them, called enterohemorrhagic E. coli (EHEC), may cause hemorrhagic colitis (HC) and hemolytic-uremic syndrome (HUS). Because of the diversity of STEC types, detection strategies for STEC and EHEC are based on the identification of Shiga toxins or the underlying genes. Cultural enrichment of STEC from test samples is needed for identification, and different protocols were developed for this purpose. Multiplex real-time PCR protocols (ISO/CEN TS13136 and USDA/FSIS MLG5B.01) have been developed to specifically identify EHEC by targeting the LEE (locus of enterocyte effacement)-encoded eae gene and genes for EHEC-associated O groups. The employment of more genetic markers (nle and CRISPR) is a future challenge for better identification of EHEC from any kinds of samples. The isolation of STEC or EHEC from a sample is required for confirmation, and different cultivation protocols and media for this purpose have been developed. Most STEC strains present in food, animals, and the environment are eae negative, but some of these strains can cause HC and HUS in humans as well. Phenotypic assays and molecular tools for typing EHEC and STEC strains are used to detect and characterize human pathogenic strains among members of the STEC group.

  18. Decolorizing kinetics of a recombinant Escherichia coli SS125 strain harboring azoreductase gene from Bacillus latrosporus RRK1.

    Science.gov (United States)

    Sandhya, S; Sarayu, K; Uma, B; Swaminathan, K

    2008-05-01

    PCR amplified product containing gene responsible for dye decolorization was cloned and expressed in Escherichia coli. The resulting recombinant strain E. coli SS125 decolorized 200mg/l azo dye (Remazol Red) at 30 degrees C at 255 mg cell/l/h, while the host E. coli (DH5 alpha) had no color removal ability. The dependence of the decolorization rate on initial dye concentration and the maximum rate occurred with the dye at 100 mg l(-1). The decolorization rate of E. coli SS125 was optimal at 37-45 degrees C. Aeration strongly-inhibited the decolorization, but decolorization occurred effectively under static and anaerobic incubation conditions. The E. coli SS125 strain also exhibited excellent stability during reported batch operation.

  19. Genetic features of human and bovine Escherichia coli O157:H7 strains isolated in Argentina.

    Science.gov (United States)

    Pianciola, L; D'Astek, B A; Mazzeo, M; Chinen, I; Masana, M; Rivas, M

    2016-02-01

    Shiga toxin-producing Escherichia coli (STEC) are important food-borne pathogens associated with human diseases. In Argentina, O157:H7 is the dominant serotype in hemolytic uremic syndrome (HUS) cases. Previously, we have described the almost exclusive circulation of human E. coli O157 strains belonging to the hypervirulent clade 8 in Neuquén Province. The aim of the present study was to investigate, by a broad molecular characterization, if this particular distribution of E. coli O157 clades in Neuquén is similar to the situation in other regions of the country and if it may be originated in a similar profile in cattle, its main reservoir. Two-hundred and eighty O157 strains (54 bovine and 226 human) isolated between 2006 and 2008 in different regions of Argentina were studied. All strains harbored rfbO157, fliCH7, eae, and ehxA genes. The predominant genotype was stx2a/stx2c in human (76.1%) and bovine (55.5%) strains. All human isolates tested by Lineage-Specific Polymorphism Assay (LSPA-6), were lineage I/II; among bovine strains, 94.1% belonged to lineage I/II and 5.9% to lineage I. No LSPA-6 lineage II isolates were detected. Single nucleotide polymorphism (SNP) analysis has revealed the existence of nine clade phylogenetic groups. In our clinical strains collection, 87.6% belonged to the hypervirulent clade 8, and 12.4% were classified as clade 4/5. In bovine isolates, 59.3% strains were clade 8, 33.3% clade 4/5 and 7.4% clade 3. More than 80% of human strains showed the presence of 6 of the 7 virulence determinants described in the TW14359 O157 strain associated with the raw spinach outbreak in the U.S. in 2006. More than 80% of bovine strains showed the presence of 3 of these factors. The q933 allele, which has been related to high toxin production, was present in 98.2% of clinical strains and 75.9% of the bovine isolates. The molecular characterization of human STEC O157 strains allows us to conclude that the particular situation previously described

  20. [Cloning and sequencing of the papA gene from uropathogenic Escherichia coli 4030 strain].

    Science.gov (United States)

    Wu, Qinggang; Zhang, Jingping; Zhao, Chuncheng; Zhu, Jianguo

    2008-09-01

    Cloning and sequencing of the papA gene from uropathogenic Escherichia coli 4030 strain to investigate the differences of the sequences of the papA of UPEC4030 strain and the ones of related genes, in order to make whether or not it was a new genotype. Cloning and sequencing methods were used to analyze the sequence of the papA of UPEC4030 strain in comparison with related sequences. The sequence analysis of papA revealed a 722 bp gene and encode 192 amino acid polypeptide. The overall homology of the papA genes between UPEC4030 and the standard strains of ten F types were 36.11%-77.95% and 22.20%-78.34% at nucleotide and deduced amino acid levels. The homology between the sequence of the reverse primers and the corresponding sequence of UPEC4030 papA was 10%-66.67%. The results confirmed that UPEC4030 strain contained a novel papA variant. UPEC4030 strain could contain an unknown papA variant or the novel genotype. The pathogenic mechanism and epidemiology related need to be further studied.

  1. Infections with avian pathogenic and fecal Escherichia coli strains display similar lung histopathology and macrophage apoptosis.

    Directory of Open Access Journals (Sweden)

    Fabiana Horn

    Full Text Available The purpose of this study was to compare histopathological changes in the lungs of chickens infected with avian pathogenic (APEC and avian fecal (A(fecal Escherichia coli strains, and to analyze how the interaction of the bacteria with avian macrophages relates to the outcome of the infection. Chickens were infected intratracheally with three APEC strains, MT78, IMT5155, and UEL17, and one non-pathogenic A(fecal strain, IMT5104. The pathogenicity of the strains was assessed by isolating bacteria from lungs, kidneys, and spleens at 24 h post-infection (p.i.. Lungs were examined for histopathological changes at 12, 18, and 24 h p.i. Serial lung sections were stained with hematoxylin and eosin (HE, terminal deoxynucleotidyl dUTP nick end labeling (TUNEL for detection of apoptotic cells, and an anti-O2 antibody for detection of MT78 and IMT5155. UEL17 and IMT5104 did not cause systemic infections and the extents of lung colonization were two orders of magnitude lower than for the septicemic strains MT78 and IMT5155, yet all four strains caused the same extent of inflammation in the lungs. The inflammation was localized; there were some congested areas next to unaffected areas. Only the inflamed regions became labeled with anti-O2 antibody. TUNEL labeling revealed the presence of apoptotic cells at 12 h p.i in the inflamed regions only, and before any necrotic foci could be seen. The TUNEL-positive cells were very likely dying heterophils, as evidenced by the purulent inflammation. Some of the dying cells observed in avian lungs in situ may also be macrophages, since all four avian E. coli induced caspase 3/7 activation in monolayers of HD11 avian macrophages. In summary, both pathogenic and non-pathogenic fecal strains of avian E. coli produce focal infections in the avian lung, and these are accompanied by inflammation and cell death in the infected areas.

  2. Comparison of cellular stress levels and green-fluorescent-protein expression in several Escherichia coli strains.

    Science.gov (United States)

    Seo, Jeong Hyun; Kang, Dong Gyun; Cha, Hyung Joon

    2003-04-01

    Constructs comprising stress-gene promoter elements from rpoH (Sigma 32), clpB or dnaK linked to a green-fluorescent-protein (GFP) expression vector were previously used as non-invasive "stress probes" in Escherichia coli. We compared cellular stress responses in four E. coli strains: production hosts JM105 and BL21, and cloning hosts HB101 and TOP10. When GFP was also used as a model for foreign protein production, we generally observed that the level of expression was inversely proportional to the level of cellular stress. JM105 showed the highest cellular stress level and very low GFP expression, while BL21 exhibited the lowest cellular stress level and the highest GFP expression, in both normal and heat-shock stress environments.

  3. [Construction of an Escherichia coli strain for sensitive detection of arsenite ion in water].

    Science.gov (United States)

    Wang, Wu; Ji, Songjun; Huang, Zhaozhu; Lu, Binbin; Lv, Jianxin

    2016-08-25

    In order to construct an Escherichia coli strain with high sensitivity and specificity to detect arsenic ion using fluorescence as reporter, a sensitive strain to arsenic ion was obtained by knocking out the gene arsB that acts as an arsenic efflux pump. The pET28b vector containing arsenite detecting cassette Pars-arsR-egfp was constructed and then transformed into arsB deleted mutant. Measuring conditions of this constructed whole-cell biosensor were optimized and its linear concentration range, limit of detection and specificity were determined. This modified biosensor was much more sensitive than that using wild-type strain as host. The optimal detection range of As³⁺ concentration was 0.013 to 42.71 μmol/L, and the limit concentration of detection was as low as 5.13 nmol/L. Thus we successfully improved the sensitivity of arsenite detecting biosensor by modification of E. coli genome, which may provide useful strategies for development and optimization of microbial sensors to detect heavy metals.

  4. Mexican unpasteurised fresh cheeses are contaminated with Salmonella spp., non-O157 Shiga toxin producing Escherichia coli and potential uropathogenic E. coli strains: A public health risk.

    Science.gov (United States)

    Guzman-Hernandez, Rosa; Contreras-Rodriguez, Araceli; Hernandez-Velez, Rosa; Perez-Martinez, Iza; Lopez-Merino, Ahide; Zaidi, Mussaret B; Estrada-Garcia, Teresa

    2016-11-21

    Fresh cheeses are a main garnish of Mexican food. Consumption of artisanal fresh cheeses is very common and most of them are made from unpasteurised cow milk. A total of 52 fresh unpasteurised cheeses of five different types were purchased from a variety of suppliers from Tabasco, Mexico. Using the most probable number method, 67% and 63% of samples were positive for faecal coliforms and E. coli, respectively; revealing their low microbiological quality. General hygienic conditions and practices of traditional cheese manufacturers were poor; most establishments had unclean cement floors, all lacked windows and doors screens, and none of the food-handlers wore aprons, surgical masks or bouffant caps. After analysing all E. coli isolates (121 strains) for the presence of 26 virulence genes, results showed that 9 (17%) samples were contaminated with diarrheagenic E. coli strains, 8 harboured non-O157 Shiga toxin producing E. coli (STEC), and one sample contained both STEC and diffusely adherent E. coli strains. All STEC strains carried the stx1 gene. Potential uropathogenic E. coli (UPEC) strains were isolated from 15 (29%) samples; the most frequent gene combination was fimA-agn43. Two samples were contaminated with Salmonella. The results demonstrated that unpasteurised fresh cheeses produced in Tabasco are of poor microbiological quality and may frequently harbour foodborne pathogens. Food safety authorities in Mexico need to conduct more rigorous surveillance of fresh cheeses. Furthermore, simple and inexpensive measures as establishing programs emphasizing good hand milking practices and hygienic manufacturing procedures may have a major effect on improving the microbiological quality of these food items. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Ciliates rapidly enhance the frequency of conjugation between Escherichia coli strains through bacterial accumulation in vesicles.

    Science.gov (United States)

    Matsuo, Junji; Oguri, Satoshi; Nakamura, Shinji; Hanawa, Tomoko; Fukumoto, Tatsuya; Hayashi, Yasuhiro; Kawaguchi, Kouhei; Mizutani, Yoshihiko; Yao, Takashi; Akizawa, Kouzi; Suzuki, Haruki; Simizu, Chikara; Matsuno, Kazuhiko; Kamiya, Shigeru; Yamaguchi, Hiroyuki

    2010-10-01

    The mechanism underlying bacterial conjugation through protozoa was investigated. Kanamycin-resistant Escherichia coli SM10λ+ carrying pRT733 with TnphoA was used as donor bacteria and introduced by conjugation into ciprofloxacin-resistant E. coli clinical isolate recipient bacteria. Equal amounts of donor and recipient bacteria were mixed together in the presence or absence of protozoa (ciliates, free-living amoebae, myxamoebae) in Page's amoeba saline for 24 h. Transconjugants were selected with Luria broth agar containing kanamycin and ciprofloxacin. The frequency of conjugation was estimated as the number of transconjugants for each recipient. Conjugation frequency in the presence of ciliates was estimated to be approximately 10⁻⁶, but in the absence of ciliates, or in the presence of other protozoa, it was approximately 10⁻⁸. Conjugation also occurred in culture of ciliates at least 2 h after incubation. Successful conjugation was confirmed by the polymerase chain reaction. Addition of cycloheximide or latrunculin B resulted in suppression of conjugation. Heat killing the ciliates or bacteria had no effect on conjugation frequency. Co-localization of green fluorescent protein-expressing E. coli and PKH-67-vital-stained E. coli was observed in the same ciliate vesicles, suggesting that both donor and recipient bacteria had accumulated in the same vesicle. In this study, the conjugation frequency of bacteria was found to be significantly higher in vesicles purified from ciliates than those in culture suspension. We conclude that ciliates rapidly enhance the conjugation of E. coli strains through bacterial accumulation in vesicles. Copyright © 2010 Elsevier Masson SAS. All rights reserved.

  6. Microarray analysis of the Ler regulon in enteropathogenic and enterohaemorrhagic Escherichia coli strains.

    Directory of Open Access Journals (Sweden)

    Lewis E H Bingle

    Full Text Available The type III protein secretion system is an important pathogenicity factor of enteropathogenic and enterohaemorrhagic Escherichia coli pathotypes. The genes encoding this apparatus are located on a pathogenicity island (the locus of enterocyte effacement and are transcriptionally activated by the master regulator Ler. In each pathotype Ler is also known to regulate genes located elsewhere on the chromosome, but the full extent of the Ler regulon is unclear, especially for enteropathogenic E. coli. The Ler regulon was defined for two strains of E. coli: E2348/69 (enteropathogenic and EDL933 (enterohaemorrhagic in mid and late log phases of growth by DNA microarray analysis of the transcriptomes of wild-type and ler mutant versions of each strain. In both strains the Ler regulon is focused on the locus of enterocyte effacement - all major transcriptional units of which are activated by Ler, with the sole exception of the LEE1 operon during mid-log phase growth in E2348/69. However, the Ler regulon does extend more widely and also includes unlinked pathogenicity genes: in E2348/69 more than 50 genes outside of this locus were regulated, including a number of known or potential pathogenicity determinants; in EDL933 only 4 extra-LEE genes, again including known pathogenicity factors, were activated. In E2348/69, where the Ler regulon is clearly growth phase dependent, a number of genes including the plasmid-encoded regulator operon perABC, were found to be negatively regulated by Ler. Negative regulation by Ler of PerC, itself a positive regulator of the ler promoter, suggests a negative feedback loop involving these proteins.

  7. The mechanisms of activation of normal human serum complement by Escherichia coli strains with K1 surface antigen.

    Science.gov (United States)

    Bugla-Płoskońska, G; Cisowska, A; Karpińska, K; Jankowski, S; Doroszkiewicz, W

    2006-01-01

    Ten E. coli K1 strains isolated from the urine of children with urinary tract infections were sensitive to the bactericidal action of normal human serum (NHS). The role of the particular mechanisms of complement activation was determined in the process of killing these strains, showing variable sensitivity to the bactericidal action of NHS; three mechanisms of activation of human complement were observed. Important role of alternative pathway activation in the bactericidal action of NHS against E. coli K1 strains independent of the classical and lectin pathways was not established.

  8. Global gene expression profiling of the asymptomatic bacteriuria Escherichia coli strain 83972 in the human urinary tract

    DEFF Research Database (Denmark)

    Hancock, Viktoria; Klemm, Per

    2006-01-01

    Urinary tract infections (UTIs) are an important health problem worldwide, with many million cases each year. Escherichia coli is the most common organism causing UTIs in humans. The asymptomatic bacteriuria E. coli strain 83972 is an excellent colonizer of the human urinary tract, where it causes...... long-term bladder colonization. The strain has been used for prophylactic purposes in patients prone to more severe and recurrent UTIs. For this study, we used DNA microarrays to monitor the expression profile of strain 83972 in the human urinary tract. Significant differences in expression levels were...

  9. First description of an Escherichia coli strain producing NDM-1 carbapenemase in Spain

    OpenAIRE

    Sole, M.; Pitart, C.; Roca, I.; Fabrega, A.; Salvador, P.; Munoz, L.; Oliveira, I.; Gascon, J.; Marco, F.; Vila, J.

    2011-01-01

    A carbapenem-resistant Escherichia coli strain (DVR22) was recovered from a stool specimen from a patient with traveler's diarrhea who had traveled to India. Molecular screening led to the first identification of NDM-1 in Spain. The blaNDM-1 gene was located in a conjugative plasmid of ca. 300 kb that also contained the blaCTX-M-15, blaTEM-1, ΔblaDHA-1, and armA genes. In addition, blaNDM-1 was preceded by an ISAba125 insertion element only found in Acinetobacter spp.

  10. First description of an Escherichia coli strain producing NDM-1 carbapenemase in Spain.

    Science.gov (United States)

    Solé, Mar; Pitart, Cristina; Roca, Ignasi; Fàbrega, Anna; Salvador, Pilar; Muñoz, Laura; Oliveira, Inés; Gascón, Joaquim; Marco, Francesc; Vila, Jordi

    2011-09-01

    A carbapenem-resistant Escherichia coli strain (DVR22) was recovered from a stool specimen from a patient with traveler's diarrhea who had traveled to India. Molecular screening led to the first identification of NDM-1 in Spain. The bla(NDM-1) gene was located in a conjugative plasmid of ca. 300 kb that also contained the bla(CTX-M-15), bla(TEM-1), Δbla(DHA-1), and armA genes. In addition, bla(NDM-1) was preceded by an ISAba125 insertion element only found in Acinetobacter spp.

  11. Transcriptional profiling of thymidine-producing strain recombineered from Escherichia coli BL21

    Directory of Open Access Journals (Sweden)

    Jin-Sook Kim

    2015-12-01

    Full Text Available DNA microarrays were used to compare the expression profiles of a thymidine overproducing strain (BLT013 and its isogenic parent, Escherichia coli BL21(DE3, when each was grown under well-defined thymidine production conditions with glycerol as carbon source. Here we describe the experimental procedures and methods in detail to reproduce the results and provide resource to be applied to similar engineering approach (available at Gene Expression Omnibus database under GSE69963. Taken together, the microarray data provide a basis for new testable hypotheses regarding enhancement of thymidine productivity and attaining a more complete understanding of nucleotide metabolism in bacteria.

  12. The genetic diversity of commensal Escherichia coli strains isolated from nonantimicrobial treated pigs varies according to age group

    DEFF Research Database (Denmark)

    Ahmed, Shahana; Olsen, John E.; Herrero-Fresno, Ana

    2017-01-01

    This is the first report on the genetic diversity of commensal E. coli from pigs reared in an antibiotic free production system and belonging to different age groups. The study investigated the genetic diversity and relationship of 900 randomly collected commensal E. coli strains from non......-antimicrobial treated pigs assigned to five different age groups in a Danish farm. Fifty-two unique REP profiles were detected suggesting a high degree of diversity. The number of strains per pig ranged from two to 13. The highest and the lowest degree of diversity were found in the early weaners group (Shannon...... diversity index, H' of 2.22) and piglets (H' of 1.46) respectively. The REP profiles, R1, R7 and R28, were the most frequently observed in all age groups. E. coli strains representing each REP profile and additional strains associated with the dominant profiles were subjected to PFGE and were assigned to 67...

  13. Development of a serogroup-specific DNA microarray for identification of Escherichia coli strains associated with bovine septicemia and diarrhea.

    Science.gov (United States)

    Liu, Bin; Wu, Fan; Li, Dan; Beutin, Lothar; Chen, Min; Cao, Boyang; Wang, Lei

    2010-05-19

    Escherichia coli strains belonging to serogroups O8, O9, O15, O26, O35, O78, O86, O101, O115 and O119 are commonly associated with septicemia or diarrhea in calves and pose a significant threat to the cattle industry worldwide. In this study, a microarray detection system targeting O-antigen-specific genes was developed for the identification of those serogroups. By testing against 186 E. coli and Shigella O-serogroup reference strains, 36 E. coli clinical isolates, and 9 representative strains of other closely related bacterial species, the microarray was shown to be specific and reproducible. The detection sensitivity was determined to be 50 ng genomic DNA. The microarray assay developed here is suitable for the detection and identification of relevant strains from environmental and/or clinical samples, and is especially useful for epidemiologic studies. Copyright 2009 Elsevier B.V. All rights reserved.

  14. Influence of Sanitizers on the Lipopolysaccharide Toxicity of Escherichia coli Strains Cultivated in the Presence of Zygosaccharomyces bailii

    Directory of Open Access Journals (Sweden)

    Lerato Mogotsi

    2014-01-01

    Full Text Available The influence of sublethal concentrations of two sanitizers, liquid iodophor and liquid hypochlorite (LH, on the growth rates and toxicity of food-borne pathogenic Escherichia coli strains grown in the presence of spoilage yeast Zygosaccharomyces bailii was assessed. When grown in combination with Z. bailii both E. coli O113 and E. coli O26 exhibited slower growth rates, except when E. coli O113 was grown in combination with Z. bailii at 0.2% LH. The growth rate of Z. bailii was not impacted by the addition of the sanitizers or by communal growth with E. coli strains. LAL and IL-6 results indicated a decrease in toxicity of pure E. coli cultures with comparable profiles for control and sanitizer exposed samples, although the LAL assay proved to be more sensitive. Interestingly, pure cultures of Z. bailii showed increased toxicity measured by LAL and decreased toxicity measured by IL-6. LAL analysis showed a decrease in toxicity of both E. coli strains grown in combination with Z. bailii, while IL-6 analysis of the mixed cultures showed an increase in toxicity. The use of LAL for toxicity determination in a mixed culture overlooks the contribution made by spoilage yeast, thus demonstrating the importance of using the appropriate method for toxicity testing in mixed microbe environments.

  15. Shiga toxigenic Escherichia coli show strain dependent reductions under dry-fermented sausage production and post-processing conditions.

    Science.gov (United States)

    Rode, Tone Mari; Holck, Askild; Axelsson, Lars; Høy, Martin; Heir, Even

    2012-04-16

    Dry-fermented sausages (DFS) are considered possible risk products regarding Shiga toxigenic Escherichia coli (STEC). We have compared the reduction of 11 E. coli isolates of various serogroups in salami during the sausage production process and during post-process measures including storage, heating and freezing. The 11 E. coli isolates, mainly STEC, included enterohaemorrhagic E. coli (EHEC) outbreak strains linked to DFS along with apathogenic E. coli. During sausage production, there was a statistically significant difference in reduction between the E. coli strains ranging from 1.3 to 2.4 log₁₀ (p0.1) between the reductions of E. coli in salami and in the TSB broth model. Results based on broth models and/or single or surrogate strains must therefore be interpreted with caution. The EHEC reducing post-processing measures tested can easily be implemented in DFS production with marginal influence on the quality of the sausages. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. 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...

  17. Characterization of Campylobacter jejuni and Campylobacter coli strains isolated in the region of Niš, Serbia

    Directory of Open Access Journals (Sweden)

    Miljković-Selimović Biljana

    2010-01-01

    Full Text Available Introduction. Campylobacter jejuni and Campylobacter coli represent one of the main causes of bacterial diarrhoea in humans. Although the disease is usually mild and self-limiting, severe chronic sequelae may occur, such as reactive arthritis, Guillain-Barré and Miller Fisher syndromes. Serotyping is used as an epidemiological marker, while post-infective polyneuropathies are associated with several O serotypes. Objective. Strains of C. jejuni and C. coli were serotyped based on heat stable (HS and heat labile (HL antigens, as well as biotypes to determine strain diversity. Methods. Campylobacter spp. was isolated using selective blood media with antibiotics. Differentiation to the species level was done by a combination of biotyping tests and by a PCR-based RFLP test. The isolates were characterised by Penner and Lior serotyping methods. Results. The serotypes showed diversity without predominant serotypes. 24 HS serotypes were detected among 29 C. jejuni strains, and seven serotypes among nine C. coli strains. HL serotyping method successfully typed 62.5% of strains. Among 16 C. jejuni strains 14 serotypes were detected, and three among four C. coli strains. A C. jejuni strain associated with a patient with Guillain-Barré syndrome was typed as biotype II, O:19. Conclusion. The biotyping and serotyping results have indicated that C. jejuni and C. coli strains in the region of Niš, Serbia are diverse and could be probably of unrelated sources of origin or reservoirs. The strain associated with the Guillain-Barré syndrome patient was serotype O:19, one of the most common in this post-infective complication.

  18. Effect of growth phase and parental cell survival in river water on plasmid transfer between Escherichia coli strains.

    OpenAIRE

    Muela, A; Pocino, M; Arana, I; Justo, J I; Iriberri, J; Barcina, I

    1994-01-01

    We evaluated the transfer to and from Escherichia coli of endogenously isolated plasmid material from the River Butrón during the growth of three donor strains and two recipient strains as well as after the survival of these parental cells in river water. Transfer frequency varied greatly during the growth of donor cells, with minimum values in the exponential phase; frequency remained constant, however, during the growth of recipient strains. After survival in river water, donor cells lost t...

  19. [The antibacterial activity of oregano essential oil (Origanum heracleoticum L.) against clinical strains of Escherichia coli and Pseudomonas aeruginosa].

    Science.gov (United States)

    Sienkiewicz, Monika; Wasiela, Małgorzata; Głowacka, Anna

    2012-01-01

    The aim of this study was to investigate the antibacterial properties of oregano (Origanum heracleoticum L.) essential oil against clinical strains of Escherichia coli and Pseudomonas aeruginosa. The antibacterial activity of oregano essential oil was investigate against 2 tested and 20 clinical bacterial strains of Escherichia coli and 20 clinical strains o Pseudomonas aeruginosa come from patients with different clinical conditions. The agar dilution method was used for microbial growth inhibition at various concentrations ofoil. Susceptibility testing to antibiotics was carried out using disc-diffusion method. The results of experiments showed that the tested oil was active against all of the clinical strains from both genus of bacteria, but strains of Escherichia coli were more sensitive to tested oil. Essential oil from Origanum heracleoticum L. inhibited the growth of Escherichia coli and Pseudomonas aeruginosa clinical strains with different patters of resistance. The obtained outcomes will enable further investigations using oregano essential oil obtained from Origanum heracleoticum L. as alternative antibacterial remedies enhancing healing process in bacterial infections and as an effective means for the prevention of antibiotic-resistant strain development.

  20. Surveillance of antimicrobial resistance in Escherichia coli strains isolated from pigs at Spanish slaughterhouses.

    Science.gov (United States)

    Teshager, T; Herrero, I A; Porrero, M C; Garde, J; Moreno, M A; Domínguez, L

    2000-07-01

    Antimicrobial resistance can make the efficient treatment of bacterial infections in humans and animals more difficult. Antimicrobial use in food animals may be one of the factors contributing to resistance. The Spanish surveillance network VAV has established a baseline of antimicrobial resistance in Escherichia coli strains from healthy pigs. Minimum inhibitory concentration and patterns of resistance to antimicrobials used in animals and humans were determined for 205 faecal strains isolated in a sampling frame of four slaughterhouses in Spain from 220 pigs in 1998. Higher levels of resistance were seen against antimicrobial agents authorised for use in food animals especially tetracycline, sulphonamides, trimethoprim and amoxycillin. All isolates were susceptible to antimicrobials employed mainly in humans such as ceftazidime, cefotaxime, imipenem, aztreonam and amikacin.

  1. Investigations of multiresistance to antibiotics and chemotherapeutics and extended spectrum beta: Lactamase effect (ESBL test in strains E.coli and salmonella originating from domestic animals

    Directory of Open Access Journals (Sweden)

    Mišić Dušan

    2006-01-01

    Full Text Available The presence of multiresistance to the effects of antibiotics and chemotherapeutics and extended spectrum beta-lactamase were examined in 45 strains of E. coli and 35 strains of Salmonella. The strains of E. coli originated from several species of domestic animals: dogs, cats, poultry, and cattle, and 30 strains of Salmonella originated from poultry, 4 strains from cattle, and 1 strain from swine. The presence of the following serovarieties was established using serological examinations: Salmonella Enteritidis 17 strains, Salmonella Gallinarum 1 strain, Salmonella Hartford 5 strains, Salmonella Anatum 1 strain, Salmonella Typhimurium 4 strains, Salmonella Agona 1 strain, Salmonella Infantis 1 strain, Salmonella Thompson var. Berlin 1 strain, Salmonella Tennessee 1 strain, Salmonella Senftenberg 1 strain, Salmonella Glostrup 1 strain, and Salmonella Hadar 1 strain. In the examinations of the listed strains we used antibiogram discs of ampicillin, amoxicillin with clavulanic acid, cephalexin, cephtriaxon, cephotaxim, cephtazidime, aztreonam, gentamycin, chloramphenicol, tetracycline, cyprofloxacine, and a combination of sulphamethoxasole and trimethoprim. The lowest prevalence of multiresistance in E. Coli strains to 3 or more antibiotics was established in dogs 20%, and the highest in 60% strains originating from swine. In 62.88% strains of Salmonella we established sensitivity to all applied antibiotics. Resistance was also established in a small number of the examined strains to ampicillin (11 strains, to tetracycline (5 strains, to amoxicillin with clavulanic acid (5 strains, to sulphamethoxasole with trimethoprim (5 strains, to gentamycin (3 strains, and to cloramphenicol (1 strain. Of all the examined strains of Salmonella, 6 strains originating from poultry exhibited multiresistence. The presence of extended spectrum beta-lactamase effects examined using the ESBL test, was not established in strains of E. coli and Salmonella strains.

  2. Molecular and Phenotypic Characterization of Escherichia coli O26:H8 among Diarrheagenic E. coli O26 Strains Isolated in Brazil

    Science.gov (United States)

    Piazza, Roxane M. F.; Delannoy, Sabine; Fach, Patrick; Saridakis, Halha O.; Pedroso, Margareth Z.; Rocha, Letícia B.; Gomes, Tânia A. T.; Vieira, Mônica A. M.; Beutin, Lothar

    2013-01-01

    Escherichia coli strains of serogroup O26 comprise two distinct groups of pathogens, characterized as enteropathogenic E. coli (EPEC) and enterohemorrhagic E. coli (EHEC). Among the several genes related to type III secretion system-secreted effector proteins, espK was found to be highly specific for EHEC O26:H11 and its stx-negative derivative strains isolated in European countries. E. coli O26 strains isolated in Brazil from infant diarrhea, foods, and the environment have consistently been shown to lack stx genes and are thus considered atypical EPEC. However, no further information related to their genetic background is known. Therefore, in this study, we aimed to discriminate and characterize these Brazilian O26 stx-negative strains by phenotypic, genetic, and biochemical approaches. Among 44 isolates confirmed to be O26 isolates, most displayed flagellar antigen H11 or H32. Out of the 13 nonmotile isolates, 2 tested positive for fliCH11, and 11 were fliCH8 positive. The identification of genetic markers showed that several O26:H11 and all O26:H8 strains tested positive for espK and could therefore be discriminated as EHEC derivatives. The presence of H8 among EHEC O26 and its stx-negative derivative isolates is described for the first time. The interaction of three isolates with polarized Caco-2 cells and with intestinal biopsy specimen fragments ex vivo confirmed the ability of the O26 strains analyzed to cause attaching-and-effacing (A/E) lesions. The O26:H32 strains, isolated mostly from meat, were considered nonvirulent. Knowledge of the virulence content of stx-negative O26 isolates within the same serotype helped to avoid misclassification of isolates, which certainly has important implications for public health surveillance. PMID:23974139

  3. Genome-Wide Survey of Genes Under Positive Selection in Avian Pathogenic Escherichia coli Strains.

    Science.gov (United States)

    Rojas, Thaís Cabrera Galvão; Lobo, Francisco Pereira; Hongo, Jorge Augusto; Vicentini, Renato; Verma, Renu; Maluta, Renato Pariz; da Silveira, Wanderley Dias

    2017-05-01

    The ability to obtain bacterial genomes from the same host has allowed for comparative studies that help in the understanding of the molecular evolution of specific pathotypes. Avian pathogenic Escherichia coli (APEC) is a group of extraintestinal strains responsible for causing colibacillosis in birds. APEC is also suggested to possess a role as a zoonotic agent. Despite its importance, APEC pathogenesis still has several cryptic pathogenic processes that need to be better understood. In this work, a genome-wide survey of eight APEC strains for genes with evidence of recombination revealed that ∼14% of the homologous groups evaluated present signs of recombination. Enrichment analyses revealed that nine Gene Ontology (GO) terms were significantly more represented in recombinant genes. Among these GO terms, several were noted to be ATP-related categories. The search for positive selection in these APEC genomes revealed 32 groups of homologous genes with evidence of positive selection. Among these groups, we found several related to cell metabolism, as well as several uncharacterized genes, beyond the well-known virulence factors ompC, lamB, waaW, waaL, and fliC. A GO term enrichment test showed a prevalence of terms related to bacterial cell contact with the external environment (e.g., viral entry into host cell, detection of virus, pore complex, bacterial-type flagellum filament C, and porin activity). Finally, the genes with evidence of positive selection were retrieved from genomes of non-APEC strains and tested as were done for APEC strains. The result revealed that none of the groups of genes presented evidence of positive selection, confirming that the analysis was effective in inferring positive selection for APEC and not for E. coli in general, which means that the study of the genes with evidence of positive selection identified in this study can contribute for the better understanding of APEC pathogenesis processes.

  4. The role of Escherichia coli strain Nissle 1917 in the gastro-intestinal diseases

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    Dorota Różańska

    2014-11-01

    Full Text Available In this paper a review of the researches on the role of Escherichia coli strain Nissle 1917 (EcN in gastrointestinal diseases was presented. EcN is a non-pathogenic strain of the Enterobacteriaceae family, which has probiotic properties. In a number of studies conducted among humans and experimental animals the application of EcN in treatment of gastrointestinal diseases was observed. Most studies about EcN has been devoted to this organism efficacy in ulcerative colitis treatment. Comparable results were obtained, by citied authors, in the treatment (sustaining remission of EcN and mesalazine in ulcerative colitis. Moreover, this probiotic therapy, compared to placebo, contributes to obtaining a faster remission and improvement of intestinal histopathology. The use of EcN in Crohn’s disease has not been the subject of as many studies as in the case of ulcerative colitis. Assessing the importance of EcN in treatment of other gastrointestinal disorders, authors of the studies observed, that in patients with irritable bowel syndrome, who receiving this probiotic there was a pain, nausea and bloating reduction. In studies conducted among children a positive impact of EcN in prevention and treatment of diarrhea was demonstrated. Similar results were obtained in studies conducted in experimental animals. Based on the presented review it can be concluded that the strain of Escherichia coli Nissle 1917 is useful in treatment of gastrointestinal diseases, especially in treatment of ulcerative colitis. This probiotic may constitute a part of treatment of irritable bowel syndrome and diarrhea. The effectiveness of this strain in treatment of Crohn’s disease is not clearly established and further research are require.

  5. Detection of virulence genes in Uropathogenic E. coli (UPEC strains by Multiplex-PCR method

    Directory of Open Access Journals (Sweden)

    Javad Mohammadi

    2017-06-01

    Full Text Available Background & Objectives: Urinary tract infection caused by E. coli is one of the most common illnesses in all age groups worldwide. Presence of virulence genes is a key factor in bacterial pathogens in uroepithelial cells. The present study was performed to detect iha, iroN, ompT genes in the Uropathogenic E.coli isolates from clinical samples using multiplex-PCR method in Kerman. Materials & Methods: In this descriptive cross-sectional study, 200 samples of patients with urinary tract infections in Kerman hospitals were collected. After biochemical and microbiological tests, all strains were tested with regard to the presence of iha, iroN, and ompT genes using multiplex-PCR method. Results: The results of Multiplex-PCR showed that all specimens had one, two, or three virulence genes simultaneously. The highest and lowest frequency distribution of genes was related to iha (56.7% and iroN (20% respectively. Conclusion: According to the prevalence of urinary tract infection in the community and distribution of resistance and virulence factors, the fast and accurate detection of the strains and virulence genes is necessary

  6. In vitro activity of available antimicrobial coated Foley catheters against Escherichia coli, including strains resistant to extended spectrum cephalosporins.

    Science.gov (United States)

    Johnson, James R; Johnston, Brian D; Kuskowski, Michael A; Pitout, Johann

    2010-12-01

    We determined the activity, comparative potency and effect durability of commercially available, antimicrobial coated Foley catheters against Escherichia coli isolates, including extended spectrum cephalosporin resistant strains. We used an inhibition zone assay (diffusible inhibition) and an adherence assay (diffusible and contact dependent inhibition) to assess the inhibitory effect of 3 currently marketed antimicrobial coated catheters, including 2 coated with silver and 1 coated with nitrofurazone, and corresponding silicone catheters against 9 E. coli strains, including 7 extended spectrum cephalosporin resistant and 2 extended spectrum cephalosporin susceptible strains, and a Pseudomonas aeruginosa reference strain. In each assay the nitrofurazone coated catheter showed the greatest and most durable (through day 5) inhibitory activity. This was comparable for extended spectrum cephalosporin resistant and extended spectrum cephalosporin susceptible E. coli strains but decreased or absent for the Pseudomonas strain. One of the 2 silver coated catheters showed sparse but measurable inhibition zone activity on day 1 but not thereafter and no statistically significant activity on adherence assay. The other lacked detectable activity using either test system. In the adherence assay the nitrofurazone coated catheter decreased the E. coli count as potently in inoculum broths as in post-sonication suspensions (median decrease more than 8 and more than 6 log(10) cfu/ml, respectively). The nitrofurazone coated catheter showed significantly greater in vitro potency and durability of the antimicrobial effect against 9 E. coli strains than the 2 silver coated catheters, of which 1 appeared completely inert. No difference in antimicrobial effect was apparent between extended spectrum cephalosporin resistant and susceptible E. coli. The clinical relevance of these in vitro findings remains to be defined. Copyright © 2010 American Urological Association Education and

  7. Improved methods of cultivation and production of deuteriated proteins from E. coli strains grown on fully deuteriated minimal medium.

    Science.gov (United States)

    Paliy, O; Bloor, D; Brockwell, D; Gilbert, P; Barber, J

    2003-01-01

    The aim was to develop reliable and economical protocols for the production of fully deuteriated biomolecules by bacteria. This required the preparation of deuterium-tolerant bacterial strains and an understanding of the physiological mechanisms of acquisition of deuterium tolerance. We report here improved methods for the cultivation of Escherichia coli on fully deuteriated minimal medium. A multi-stage adaptation protocol was developed; this included repeated plating and selection of colonies and resulted in highly deuterium-tolerant cell cultures. Three E. coli strains, JM109, MRE600 and MRE600Rif, were adapted to growth on deuteriated succinate medium. This is the first report of JM109 being adapted to deuteriated minimal media. The adapted strains showed good, consistent growth rates and were capable of being transformed with plasmids. Expression of heterologous proteins in these strains was reliable and yields were consistently high (100-200 mg l-1). We also show that all E. coli cells are inherently capable of growth on deuteriated media. We have developed a new adaptation protocol that resulted in three highly deuterium-tolerant E. coli strains. Deuterium-adapted cultures produced good yields of a deuteriated recombinant protein. We suggest that E. coli cells are inherently capable of growth on deuteriated media, but that non-specific mutations enhance deuterium tolerance. Thus plating and selection of colonies leads to highly deuterium-tolerant strains. An understanding of the mechanism of adaptation of E. coli to growth on deuteriated media allows strategies for the development of disabled deuterium-tolerant strains suitable for high-level production of deuteriated recombinant proteins and other biomolecules. This is of particular importance for nuclear magnetic resonance and neutron scattering studies of biomolecules.

  8. Functional activities of the Tsh protein from avian pathogenic Escherichia coli (APEC) strains.

    Science.gov (United States)

    Kobayashi, Renata K; Gaziri, Luis Carlos; Vidotto, Marilda C

    2010-12-01

    The temperature-sensitive hemagglutinin (Tsh) expressed by strains of avian pathogenic Escherichia (E.) coli (APEC) has both agglutinin and protease activities. Tsh is synthesized as a 140 kDa precursor protein, whose processing results in a 106 kDa passenger domain (Tsh(s)) and a 33 kDa β-domain (Tsh(β)). In this study, both recombinant Tsh (rTsh) and supernatants from APEC, which contain Tsh(s) (106 kDa), caused proteolysis of chicken tracheal mucin. Both rTsh (140 kDa) and pellets from wild-type APEC, which contain Tsh(β) (33 kDa), agglutinated chicken erythrocytes. On Western blots, the anti-rTsh antibody recognized the rTsh and 106 kDa proteins in recombinant E. coli BL21/pET 101-Tsh and in the supernatants from APEC grown at either 37°C or 42°C. Anti-rTsh also recognized a 33 kDa protein in the pellets from APEC13 cultures grown in either Luria-Bertani agar, colonization factor antigen agar, or mucin agar at either 26°C, 37°C, or 42°C, and in the extracts of outer membrane proteins of APEC. The 106 kDa protein was more evident when the bacteria were grown at 37°C in mucin agar, and it was not detected when the bacteria were grown at 26°C in any of the culture media used in this study. Chicken anti-Tsh serum inhibited hemagglutinating and mucinolytic activities of strain APEC13 and recombinant E. coli BL21/pET101-Tsh. This work suggests that the mucinolytic activity of Tsh might be important for the colonization of the avian tracheal mucous environment by APEC.

  9. Large-scale genomic sequencing of extraintestinal pathogenic Escherichia coli strains

    Science.gov (United States)

    Salipante, Stephen J.; Roach, David J.; Kitzman, Jacob O.; Snyder, Matthew W.; Stackhouse, Bethany; Butler-Wu, Susan M.; Lee, Choli; Cookson, Brad T.

    2015-01-01

    Large-scale bacterial genome sequencing efforts to date have provided limited information on the most prevalent category of disease: sporadically acquired infections caused by common pathogenic bacteria. Here, we performed whole-genome sequencing and de novo assembly of 312 blood- or urine-derived isolates of extraintestinal pathogenic (ExPEC) Escherichia coli, a common agent of sepsis and community-acquired urinary tract infections, obtained during the course of routine clinical care at a single institution. We find that ExPEC E. coli are highly genomically heterogeneous, consistent with pan-genome analyses encompassing the larger species. Investigation of differential virulence factor content and antibiotic resistance phenotypes reveals markedly different profiles among lineages and among strains infecting different body sites. We use high-resolution molecular epidemiology to explore the dynamics of infections at the level of individual patients, including identification of possible person-to-person transmission. Notably, a limited number of discrete lineages caused the majority of bloodstream infections, including one subclone (ST131-H30) responsible for 28% of bacteremic E. coli infections over a 3-yr period. We additionally use a microbial genome-wide-association study (GWAS) approach to identify individual genes responsible for antibiotic resistance, successfully recovering known genes but notably not identifying any novel factors. We anticipate that in the near future, whole-genome sequencing of microorganisms associated with clinical disease will become routine. Our study reveals what kind of information can be obtained from sequencing clinical isolates on a large scale, even well-characterized organisms such as E. coli, and provides insight into how this information might be utilized in a healthcare setting. PMID:25373147

  10. Characterization of enterohemorrhagic Escherichia coli O111 and O157 strains isolated from outbreak patients in Japan.

    Science.gov (United States)

    Watahiki, Masanori; Isobe, Junko; Kimata, Keiko; Shima, Tomoko; Kanatani, Jun-ichi; Shimizu, Miwako; Nagata, Akihiro; Kawakami, Keiko; Yamada, Mikiko; Izumiya, Hidemasa; Iyoda, Sunao; Morita-Ishihara, Tomoko; Mitobe, Jiro; Terajima, Jun; Ohnishi, Makoto; Sata, Tetsutaro

    2014-08-01

    In April and May 2011, there was a serious food-poisoning outbreak in Japan caused by enterohemorrhagic Escherichia coli (EHEC) strains O111:H8 and O157:H7 from raw beef dishes at branches of a barbecue restaurant. This outbreak involved 181 infected patients, including 34 hemolytic-uremic syndrome (HUS) cases (19%). Among the 34 HUS patients, 21 developed acute encephalopathy (AE) and 5 died. Patient stool specimens yielded E. coli O111 and O157 strains. We also detected both EHEC O111 stx2 and stx-negative E. coli O111 strains in a stock of meat block from the restaurant. Pulsed-field gel electrophoresis (PFGE) and multilocus variable-number tandem-repeat analysis (MLVA) showed that the stx-negative E. coli O111 isolates were closely related to EHEC O111 stx2 isolates. Although the EHEC O157 strains had diverse stx gene profiles (stx1, stx2, and stx1 stx2), the PFGE and MLVA analyses indicated that these isolates originated from a single clone. Deletion of the Stx2-converting prophage from the EHEC O111 stx2 isolates was frequently observed during in vitro growth, suggesting that strain conversion from an EHEC O111 stx2 to an stx-negative strain may have occurred during infection. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  11. Resistance to drugs and heavy metals, colicin production, and biochemical characteristics of selected bovine and porcine Escherichia coli strains.

    Science.gov (United States)

    Harnett, N M; Gyles, C L

    1984-11-01

    A study was made of resistance to heavy metals and antibiotics, biochemical characteristics, and colicinogeny in selected strains of Escherichia coli of O serogroups 8, 9, 20, 64, 101, and X46. Of 42 strains that were investigated, 26 were porcine enterotoxigenic E. coli (ETEC), 8 were porcine non-enterotoxigenic E. coli (NETEC), and 8 were bovine ETEC. Multiple resistance to antimicrobial agents was common among the strains, and resistance to chloramphenicol and kanamycin was less common than resistance to other drugs, possibly reflecting the lower frequency of use of these agents in pigs and calves. Colicin production was a more common property of porcine ETEC (80.8%) than of porcine NETEC (25%), and all porcine ETEC of O serogroups 101 and 64 were colicinogenic. Equal numbers of bovine ETEC strains were colicinogenic as were non-colicinogenic. Resistance of bovine and porcine strains to sodium arsenate, mercury, and tellerium was 90, 16, and 5%, respectively. There was a close relationship between serogroup and biochemical reactions among the E. coli strains tested.

  12. Resistance to drugs and heavy metals, colicin production, and biochemical characteristics of selected bovine and porcine Escherichia coli strains.

    Science.gov (United States)

    Harnett, N M; Gyles, C L

    1984-01-01

    A study was made of resistance to heavy metals and antibiotics, biochemical characteristics, and colicinogeny in selected strains of Escherichia coli of O serogroups 8, 9, 20, 64, 101, and X46. Of 42 strains that were investigated, 26 were porcine enterotoxigenic E. coli (ETEC), 8 were porcine non-enterotoxigenic E. coli (NETEC), and 8 were bovine ETEC. Multiple resistance to antimicrobial agents was common among the strains, and resistance to chloramphenicol and kanamycin was less common than resistance to other drugs, possibly reflecting the lower frequency of use of these agents in pigs and calves. Colicin production was a more common property of porcine ETEC (80.8%) than of porcine NETEC (25%), and all porcine ETEC of O serogroups 101 and 64 were colicinogenic. Equal numbers of bovine ETEC strains were colicinogenic as were non-colicinogenic. Resistance of bovine and porcine strains to sodium arsenate, mercury, and tellerium was 90, 16, and 5%, respectively. There was a close relationship between serogroup and biochemical reactions among the E. coli strains tested. PMID:6391383

  13. Characterization of Enterohemorrhagic Escherichia coli O111 and O157 Strains Isolated from Outbreak Patients in Japan

    Science.gov (United States)

    Isobe, Junko; Kimata, Keiko; Shima, Tomoko; Kanatani, Jun-ichi; Shimizu, Miwako; Nagata, Akihiro; Kawakami, Keiko; Yamada, Mikiko; Izumiya, Hidemasa; Iyoda, Sunao; Morita-Ishihara, Tomoko; Mitobe, Jiro; Terajima, Jun; Ohnishi, Makoto; Sata, Tetsutaro

    2014-01-01

    In April and May 2011, there was a serious food-poisoning outbreak in Japan caused by enterohemorrhagic Escherichia coli (EHEC) strains O111:H8 and O157:H7 from raw beef dishes at branches of a barbecue restaurant. This outbreak involved 181 infected patients, including 34 hemolytic-uremic syndrome (HUS) cases (19%). Among the 34 HUS patients, 21 developed acute encephalopathy (AE) and 5 died. Patient stool specimens yielded E. coli O111 and O157 strains. We also detected both EHEC O111 stx2 and stx-negative E. coli O111 strains in a stock of meat block from the restaurant. Pulsed-field gel electrophoresis (PFGE) and multilocus variable-number tandem-repeat analysis (MLVA) showed that the stx-negative E. coli O111 isolates were closely related to EHEC O111 stx2 isolates. Although the EHEC O157 strains had diverse stx gene profiles (stx1, stx2, and stx1 stx2), the PFGE and MLVA analyses indicated that these isolates originated from a single clone. Deletion of the Stx2-converting prophage from the EHEC O111 stx2 isolates was frequently observed during in vitro growth, suggesting that strain conversion from an EHEC O111 stx2 to an stx-negative strain may have occurred during infection. PMID:24829231

  14. Multi-omics Quantification of Species Variation of Escherichia coli Links Molecular Features with Strain Phenotypes

    DEFF Research Database (Denmark)

    Monk, Jonathan M; Koza, Anna; Campodonico, Miguel A

    2016-01-01

    Escherichia coli strains are widely used in academic research and biotechnology. New technologies for quantifying strain-specific differences and their underlying contributing factors promise greater understanding of how these differences significantly impact physiology, synthetic biology......, metabolic engineering, and process design. Here, we quantified strain-specific differences in seven widely used strains of E. coli (BL21, C, Crooks, DH5a, K-12 MG1655, K-12 W3110, and W) using genomics, phenomics, transcriptomics, and genome-scale modeling. Metabolic physiology and gene expression varied...... widely with downstream implications for productivity, product yield, and titer. These differences could be linked to differential regulatory structure. Analyzing high-flux reactions and expression of encoding genes resulted in a correlated and quantitative link between these sets, with strain...

  15. Evaluation of the Escherichia coli (E.coli Strains based on protein profiles obtained from traditional Ice cream in Isfahan City

    Directory of Open Access Journals (Sweden)

    Maryam Ranjbar

    2016-06-01

    Full Text Available Introduction: Bacterial strains present in food products undergo different thermal processes such as coldness and warmth. Such cases cause a shock in bacteria and force the bacteria to produce proteins and partly, develop a change in the production of enzyme. This can give the strain a special characteristic, knowledge of this characteristic will contribute to a timely and more precise identification. Materials and methods: During this time more than 100 samples have been examined, out of which, 48 Indol positive isolation samples were examined by phenotypic tests and sodium dodecyle sulphate polyacrylamide gel electrophoresis (SDS- PAGE. Results: – The results of numerical analysis of phenotypic characteristics and protein patterns showed that only 79% of the collected isolates (phenon 1 and 2 could be identified as E.coli compared with reference strains. E.coli strains from ice creams were showed some Variation in banding patterns. Major differences were observed in protein bands between 23.59 - and 20.79 -kDa molecular mass range which the isolates were compared with reference strains. Discussion and conclusion: Our study concluded that food’s bacterial strains are influenced by temperatures in different processes and also it could stimulate the production of proteins or change the enzymes. Therefore, The reason of taking care of the issues is that changes in the proteins’ structures can lead to change in the biochemical properties, and finally this change can misguide us. Further research is being performed to characterize these atypical strains by molecular methods.

  16. Comparison of antimicrobial resistance in Escherichia coli, Staphylococcus aureus, and Listeria monocytogenes strains isolated from organic and conventional poultry meat.

    Science.gov (United States)

    Miranda, J M; Vázquez, B I; Fente, C A; Calo-Mata, P; Cepeda, A; Franco, C M

    2008-12-01

    The presence of Escherichia coli, Staphylococcus aureus, and Listeria monocytogenes was determined in 55 samples of organic poultry meat and in 61 samples of conventional poultry meat. A total of 220 E. coli, 192 S. aureus, and 71 L. monocytogenes strains were analyzed by an agar disk diffusion assay for their resistance to ampicillin, cephalothin, chloramphenicol, ciprofloxacin, doxycycline, fosfomycin, gentamicin, nitrofurantoin, streptomycin, and sulfisoxazole (E. coli); chloramphenicol, ciprofloxacin, clindamycin, doxycycline, erythromycin, gentamicin, nitrofurantoin, oxacillin, and sulfisoxazole (S. aureus); and chloramphenicol, doxycycline, erythromycin, gentamicin, sulfisoxazole, and vancomycin (L. monocytogenes). The results indicated a significantly higher (P organic poultry meat as compared with conventional poultry meat. E. coli isolated from organic poultry meat exhibited lower levels of antimicrobial resistance against 7 of the 10 antimicrobials tested as compared with isolates recovered from conventional meat. In the case of S. aureus and L. monocytogenes isolated from conventional poultry, antimicrobial resistance was significantly higher only for doxycycline as compared with strains isolated from organic poultry. In the case of E. coli, the presence of multiresistant strains was significantly higher (P conventional poultry meat as compared with organic poultry meat. Organically farmed poultry samples showed significantly lower development of antimicrobial resistance in intestinal bacteria such as E. coli.

  17. Genotypes and virulence characteristics of Shiga toxin-producing Escherichia coli O104 strains from different origins and sources.

    Science.gov (United States)

    Miko, Angelika; Delannoy, Sabine; Fach, Patrick; Strockbine, Nancy A; Lindstedt, Björn Arne; Mariani-Kurkdjian, Patricia; Reetz, Jochen; Beutin, Lothar

    2013-12-01

    Sixty-two Escherichia coli strains carrying the wzxO104-gene from different sources, origins and time periods were analyzed for their serotypes, virulence genes and compared for genomic similarity by pulsed-field gel-electrophoresis (PFGE). The O104 antigen was present in 55 strains and the structurally and genetically related capsular antigen K9 in five strains. The presence of 49 genes associated with enteropathogenic E. coli (EPEC), enteroaggregative E. coli (EAEC) and enterohemorrhagic E. coli (EHEC) was investigated. Fifty-four strains of serotypes O104:H2 (n=1), O104:H4 (n=37), O104:H7 (n=5) and O104:H21 (n=11) produced Shiga-toxins (Stx). Among STEC O104, a close association between serotype, virulence gene profile and genomic similarity was found. EAEC virulence genes were only present in STEC O104:H4 strains. EHEC-O157 plasmid-encoded genes were only found in STEC O104:H2, O104:H7 and O104:H21 strains. None of the 62 O104 or K9 strains carried an eae-gene involved in the attaching and effacing phenotype. The 38 O104:H4 strains formed a single PFGE-cluster (>83.7% similarity). Thirty-one of these strains were from the European O104:H4 outbreak in 2011. The outbreak strains and older O104:H4 strains from Germany (2001), Georgia and France (2009) clustered together at>86.2% similarity. O104:H4 strains isolated between 2001 and 2009 differed for some plasmid-encoded virulence genes compared to the outbreak strains from 2011. STEC O104:H21 and STEC O104:H7 strains isolated in the U.S. and in Europe showed characteristic differences in their Stx-types, virulence gene and PFGE profiles indicating that these have evolved separately. E. coli K9 strains were not associated with virulence and were heterogeneous for their serotypes and PFGE profiles. Copyright © 2013 Elsevier GmbH. All rights reserved.

  18. Serotype O18 avian pathogenic and neonatal meningitis Escherichia coli strains employ similar pathogenic strategies for the onset of meningitis

    Science.gov (United States)

    Krishnan, Subramanian; Chang, Alexander C; Hodges, Jacqueline; Couraud, Pierre-Olivier; Romero, Ignacio A; Weksler, Babette; Nicholson, Bryon A; Nolan, Lisa K; Prasadarao, Nemani V

    2015-01-01

    Neonatal meningitis Escherichia coli K1 (NMEC) are thought to be transmitted from mothers to newborns during delivery or by nosocomial infections. However, the source of E. coli K1 causing these infections is not clear. Avian pathogenic E. coli (APEC) have the potential to cause infection in humans while human E. coli have potential to cause colibacillosis in poultry, suggesting that these strains may lack host specificity. APEC strains are capable of causing meningitis in newborn rats; however, it is unclear whether these bacteria use similar mechanisms to that of NMEC to establish disease. Using four representative APEC and NMEC strains that belong to serotype O18, we demonstrate that these strains survive in human serum similar to that of the prototypic NMEC strain E44, a derivative of RS218. These bacteria also bind and enter both macrophages and human cerebral microvascular endothelial cells (HCMEC/D3) with similar frequency as that of E44. The amino acid sequences of the outer membrane protein A (OmpA), an important virulence factor in the pathogenesis of meningitis, are identical within these representative APEC and NMEC strains. Further, these strains also require FcγRI-α chain (CD64) and Ecgp96 as receptors for OmpA in macrophages and HCMEC/D3, respectively, to bind and enter these cells. APEC and NMEC strains induce meningitis in newborn mice with varying degree of pathology in the brains as assessed by neutrophil recruitment and neuronal apoptosis. Together, these results suggest that serotype O18 APEC strains utilize similar pathogenic mechanisms as those of NMEC strains in causing meningitis. PMID:26407066

  19. Efficient free fatty acid production in engineered Escherichia coli strains using soybean oligosaccharides as feedstock.

    Science.gov (United States)

    Wang, Dan; Wu, Hui; Thakker, Chandresh; Beyersdorf, Jared; Bennett, George N; San, Ka-Yiu

    2015-01-01

    To be competitive with current petrochemicals, microbial synthesis of free fatty acids can be made to rely on a variety of renewable resources rather than on food carbon sources, which increase its attraction for governments and companies. Industrial waste soybean meal is an inexpensive feedstock, which contains soluble sugars such as stachyose, raffinose, sucrose, glucose, galactose, and fructose. Free fatty acids were produced in this report by introducing an acyl-ACP carrier protein thioesterase and (3R)-hydroxyacyl-ACP dehydratase into E. coli. Plasmid pRU600 bearing genes involved in raffinose and sucrose metabolism was also transformed into engineered E. coli strains, which allowed more efficient utilization of these two kinds of specific oligosaccharide present in the soybean meal extract. Strain ML103 (pRU600, pXZ18Z) produced ~1.60 and 2.66 g/L of free fatty acids on sucrose and raffinose, respectively. A higher level of 2.92 g/L fatty acids was obtained on sugar mixture. The fatty acid production using hydrolysate obtained from acid or enzyme based hydrolysis was evaluated. Engineered strains just produced ~0.21 g/L of free fatty acids with soybean meal acid hydrolysate. However, a fatty acid production of 2.61 g/L with a high yield of 0.19 g/g total sugar was observed on an enzymatic hydrolysate. The results suggest that complex mixtures of oligosaccharides derived from soybean meal can serve as viable feedstock to produce free fatty acids. Enzymatic hydrolysis acts as a much more efficient treatment than acid hydrolysis to facilitate the transformation of industrial waste from soybean processing to high value added chemicals. © 2015 American Institute of Chemical Engineers.

  20. Prevalence of Verocytotoxigenic Escherichia coli strains isolated from raw beef in southern Italy.

    Science.gov (United States)

    Nobili, Gaia; Franconieri, Ilenia; La Bella, Gianfranco; Basanisi, Maria Grazia; La Salandra, Giovanna

    2017-09-18

    Verocytotoxin (VT)-producing Escherichia coli (VTEC) are a significant foodborne public health hazard, where most human infections are associated with six serogroups (O157, O26, O103, O145, O111 and O104). VTEC was the fourth most commonly reported zoonosis in the EU in 2015, with 5901 confirmed human cases. Ruminant animals, including cattle, are a major reservoir of VTEC. The consumption of VTEC-contaminated animal-derived foodstuffs, especially undercooked ground beef, is an important transmission route. To the best of our knowledge, there are few data available on the contamination of VTEC in meat products in Italy. During 2015 and 2016, 250 raw meat samples were collected from retail markets in southern Italy (Apulia) and analysed for the occurrence of vtx genes (vtx1/vtx2) at the Istituto Zooprofilattico Sperimentale della Puglia e della Basilicata (IZS PB, Italy). In addition, the isolates were characterized by determining the presence of VTEC main virulence factors, the antimicrobial resistance profiles and the genetic relatedness by pulsed-field gel electrophoresis (PFGE). The results have shown that 8.4% (21/250) of the samples were positive for vtx genes in the preliminary screening step but VTEC strains were isolated from only 2% (5/250) of overall meat analysed samples, including raw ground beef, beef hamburger and beef carpaccio. 5 isolates displayed a multi-drug resistance phenotype. All VTEC strains were analysed by XbaI-PFGE and dendrogram revealed 5 distinct restriction profiles, indicating their relatively high genetic diversity. Although this study demonstrates a low prevalence of VTEC in raw beef marketed in southern Italy, the presence of potentially pathogenic E. coli strains points to the need for proper hygiene during meat production to reduce the risk of foodborne illness and transmission of multi-drug resistant organisms via foods to humans. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  1. Inactivation and injury of pressure-resistant strains of Escherichia coli O157 and Listeria monocytogenes in fruit juices.

    Science.gov (United States)

    Jordan, S L; Pascual, C; Bracey, E; Mackey, B M

    2001-09-01

    To investigate methods for inactivating a pressure-resistant strain of Escherichia coli O157 in fruit juices. Cells of a pressure-resistant strain of E. coli O157 (C9490) were exposed to pressures of between, 0.1 and 500 MPa for 5 min in orange, apple or tomato juice. Treatment at 500 MPa achieved an immediate reduction of 5 log units in apple juice (pH 3.5) and tomato juice (pH 4.1), but only about a 1-2 log10 reduction in orange juice (pH 3.8). The greater level of inactivation in tomato juice than in orange juice of lower pH was due to the presence of low levels (0.7%) of salt in the tomato juice. With the type-strain of E. coli (ATCC 11775) and Listeria monocytogenes NCTC 11994, similar levels of inactivation were achieved at pressures 200 MPa lower. Following storage of pressure-treated orange juice at 4 degrees C for 24 h or 25 degrees C for 3 h, the level of inactivation of E. coli O157 strain C9490 increased to 4.4 or > 7 log10 units, respectively. Treatment at 500 MPa may be insufficient to achieve a '5D' reduction in counts of pressure-resistant strains of E. coli, but subsequent death during storage substantially increases process lethality. Commercially-practicable pressure processes can be used to inactivate even the most pressure-and acid-resistant strains of E. coli O157, provided that processing and subsequent storage conditions are carefully optimized.

  2. [Occurrence of Shiga toxigenic Escherichia coli strains in pigs and cattle at slaughterhouses in the Czech Republic in 2013].

    Science.gov (United States)

    Koláčková, Ivana; Házová, Klára; Skočková, Alena; Karpíšková, Renáta

    2014-06-01

    This study was performed in cooperation with the State Veterinary Administration (SVA) in order to monitor the occurrence of Shiga toxin-producing Escherichia coli isolates in swabs from the carcasses of pigs and cattle at slaughterhouses. From June to August 2013, SVA staff took 168 swabs from cattle and 318 from pigs at 157 different slaughters in the Czech Republic. Basic processing of the samples was carried out in the State Veterinary Institutes (SVIs) in Prague, Jihlava and Olomouc according to the methodical process coordinated by the National reference laboratory (NRL) for Escherichia coli (Czech Ministry of Agriculture). The procedure was based on the guideline ISO TS 13136. Out of the 486 swabs, twenty-two positive samples were detected. There were a total of 22 isolates of Shiga toxigenic E. coli (STEC) and 1 strain with the characteristic of enterohemorrhagic E. coli (EHEC). Genes typical for enteroaggregative E. coli (EAggEC) were not found in any of the isolates. Most STEC strains originated from pigs. The stx1 gene was detected twice (stx1a, stx1d) and the stx2 gene 13 times (12 times stx2e, once stx2a). Seven STEC isolates were detected from samples of cattle origin. One strain was stx1 (stx1a) -positive, the stx2 gene was found 6 times (4 stx2e, 1 stx2a and 1 stx2c). One isolate carried simultaneously both stx1a and stx2a. Each of the serogroups O91, O113 and O146 described as etiological agents of severe disease in humans were detected only once. None of these strains harbored additional virulence factors typical for strains causing serious illness. RESULTS of this study show the overall prevalence of Shiga toxigenic E. coli of 4.5 % and 0.2 % of enterohemorrhagic strains in the studied samples. Raw meat originating from local farms does not currently represent an important source of STEC for humans.

  3. Novel effects of the prototype translocating Escherichia coli, strain C25 on intestinal epithelial structure and barrier function.

    Science.gov (United States)

    Zareie, Mehri; Riff, Jason; Donato, Kevin; McKay, Derek M; Perdue, Mary H; Soderholm, Johan D; Karmali, Mohamed; Cohen, Mitchell B; Hawkins, Jennifer; Sherman, Philip M

    2005-12-01

    Intestinal bacteria play an etiologic role in triggering and perpetuating chronic inflammatory bowel disorders. However, the precise mechanisms whereby the gut microflora influences intestinal cell function remain undefined. Therefore, the effects of the non-pathogenic prototype translocating Escherichia coli, strain C25 on the barrier properties of human T84 and Madine-Darby canine kidney type 1 epithelial cells were examined. T-84 cells were also infected with commensal E. coil, strains F18 and HB101, and enterohaemorrhagic E. coli, serotype O157:H7. Strains F18 and HB101 had no effect on transepithelial electrical resistance (TER) of T84 monolayers. By contrast, epithelial cells infected with strain C25 displayed a time-dependent decrease in TER, preceded by an altered distribution of the cytoskeletal protein alpha-actinin, comparable to infection with E. coli O157:H7. E. coli C25 infection also led to activation of nuclear factor kappaB (NF-kappaB), interleukin-8 secretion and alterations in localization of claudin-1, but not zona occludens-1 or claudin-4, in T84 cells. There were adherent C25 bacteria on the intact apical surface of infected T84 cells, while mitochondria appeared swollen and vacuolated. These novel findings demonstrate the ability of a translocating commensal bacterium to adhere to and modulate intestinal epithelial barrier function and to induce morphological changes in a manner distinct from the known enteric pathogen, E. coli O157:H7.

  4. Dimeric and trimeric fusion proteins generated with fimbrial adhesins of uropathogenic Escherichia coli

    Directory of Open Access Journals (Sweden)

    Víctor Manuel Luna-Pineda

    2016-10-01

    polyclonal antibodies generated against FimH, CsgA, PapG, FC, and FCP blocked the adhesion of the CFT073 E. coli strain to HTB5 bladder cells. In conclusion, the FC and FCP proteins were highly stable, demonstrated antigenic properties, and induced cytokine release (IL-6 and IL-8; furthermore, antibodies generated against these proteins showed protection against bacterial adhesion.

  5. Virulence genes and antimicrobial susceptibility of lactose-negative and lactose-positive strains of Escherichia coli isolated from pregnant women and neonates.

    Science.gov (United States)

    Kaczmarek, Agnieszka; Skowron, Krzysztof; Budzyńska, Anna; Grudlewska, Katarzyna; Gospodarek-Komkowska, Eugenia

    2017-09-01

    Escherichia coli can cause serious infections in the neonates and pregnant women. Although E. coli is widely studied, E. coli lactose-negative (lac-) strains have been rarely described before. So, the aim of this study was to compare lac- and lactose-positive (lac+) E. coli strains in respect of antimicrobial susceptibility and the frequency of virulence genes (VGs). The study included 58 lac+ and 58 lac- E. coli strains isolated from pregnant women and neonates. Culture and the results of biochemical reactions were conducted for lac- and lac+ E. coli identification and differentiation. Disc diffusion test was performed to study the antimicrobial susceptibility of the isolates, and PCR was used to detect VGs. Resistance to at least one of the tested antibiotics was found among 14 (25.9%) E. coli lac+ and in 26 (44.9%) E. coli lac- strains. Both lac+ and lac- E. coli strains were mostly resistant to ampicillin (22.4 and 39.7%) and ticarcillin (20.7 and 39.7%). None of the tested strains produced extended-spectrum β-lactamases (ESBLs). Genes fimH, fimA, iutA, sfa/foc, neuC, ibeA, and hlyF were detected, respectively, in 96.6, 82.8, 32.8, 24.1, 22.4, 12.1, and 6.9% of lac+ E. coli strains and in 94.8, 86.2, 48.3, 19.0, 8.6, 8.6, and 1.7% of lac- strains. The antimicrobial susceptibility and the pathogenic potential of both tested groups of E. coli strains are similar. Therefore, omitting E. coli lac- strains as a potential etiological agent of infections may pose a threat to the health and life of both mothers and neonates.

  6. [Distribution and diversity of conjugative plasmids among some multiple antibiotic resistant E.coli strains isolated from river waters].

    Science.gov (United States)

    Cernat, Ramona; Lazăr, Veronica; Balotescu, Carmen; Cotar, Ani; Coipan, Elena; Cojocaru, Cristina

    2002-01-01

    In natural bacterial communities the microbial structure and functions are subjected to dynamic environmental and genetic adaptation. Plasmid-mediated horizontal genes transfer has a major impact on the adaptability of bacteria, exemplified by the interspecific and intergeneric transfer of antibioresistance genes in a variety of aquatic media. The high incidence of resistant bacteria has been documented for fresh waters, marine waters and chronically polluted waters. The aim of this study was to establish the distribution and diversity of plasmids and to study the transfer of plasmids harboring multiple antimicrobial-resistance determinants (R plasmids) belong to 12 multiple antibiotic resistant E. coli strains isolated from river waters. Antimicrobial resistance patterns were performed for aminoglycosides (gentamycin, kanamycin), beta-lactams (ampicillin), cephalosporins (ceftazidime and cefotaxime), tetracycline, nalidixic acid and chloramphenicol by disk diffusion method following NCCLS recommendations. Minimum inhibitory concentrations (MICs) were performed using dilution method in Mueller-Hinton broth with a 0.06-64 micrograms/ml concentration range for all antimicrobials and bacterial inoculum corresponding to 0.5 standard of the McFarland scale. For the data analysis NCCLS breakpoints for resistance and sensitivity were used. Bacterial plasmid isolation was performed by an alkaline lysis method. Genetic characterization was performed by agarose gel electrophoresis and spectrophotometric analysis. R-plasmid transfer frequencies were estimated by conjugation of drug-resistant E. coli strains used as donors with E. coli DH5 alpha F recipient marked with chromosomal resistance to nalidixic acid (Nal). The drug resistance markers possessed by a particular donor strain were sequentially used to screen for R+ transconjugants by incorporation the particular drug in the selective media. All E. coli strains are multiple antibiotic resistant, 65% of them being

  7. SHuffle, a novel Escherichia coli protein expression strain capable of correctly folding disulfide bonded proteins in its cytoplasm

    Directory of Open Access Journals (Sweden)

    Lobstein Julie

    2012-05-01

    Full Text Available Abstract Background Production of correctly disulfide bonded proteins to high yields remains a challenge. Recombinant protein expression in Escherichia coli is the popular choice, especially within the research community. While there is an ever growing demand for new expression strains, few strains are dedicated to post-translational modifications, such as disulfide bond formation. Thus, new protein expression strains must be engineered and the parameters involved in producing disulfide bonded proteins must be understood. Results We have engineered a new E. coli protein expression strain named SHuffle, dedicated to producing correctly disulfide bonded active proteins to high yields within its cytoplasm. This strain is based on the trxB gor suppressor strain SMG96 where its cytoplasmic reductive pathways have been diminished, allowing for the formation of disulfide bonds in the cytoplasm. We have further engineered a major improvement by integrating into its chromosome a signal sequenceless disulfide bond isomerase, DsbC. We probed the redox state of DsbC in the oxidizing cytoplasm and evaluated its role in assisting the formation of correctly folded multi-disulfide bonded proteins. We optimized protein expression conditions, varying temperature, induction conditions, strain background and the co-expression of various helper proteins. We found that temperature has the biggest impact on improving yields and that the E. coli B strain background of this strain was superior to the K12 version. We also discovered that auto-expression of substrate target proteins using this strain resulted in higher yields of active pure protein. Finally, we found that co-expression of mutant thioredoxins and PDI homologs improved yields of various substrate proteins. Conclusions This work is the first extensive characterization of the trxB gor suppressor strain. The results presented should help researchers design the appropriate protein expression conditions using

  8. GENE TRANSFER BY F′ STRAINS OF ESCHERICHIA COLI K-12 II.

    Science.gov (United States)

    Pittard, James; Adelberg, Edward A.

    1963-01-01

    Pittard, James (Yale University, New Haven, Conn.) and Edward A. Adelberg. Gene transfer by F′ strains of Escherichia coli K-12. II. Interaction between F-merogenote and chromosome during transfer. J. Bacteriol. 85:1402–1408. 1963.—When F′ strains harboring the F-merogenate F14 are mated with female recipients, the transfer of the F-merogenote begins, in the majority of cases, before chromosome transfer. The markers on F14 are transferred in the sequence met-1, arg-1, ilva-16, and sex-factor, met-1 being transferred first and sex-factor being transferred last, 9 min after met-1. In the class of zygotes that have received both the F-merogenote marker met-1 and the chromosomal marker xyl or mal, the gradient of recombination frequencies for the F-merogenote markers arg-1 and ilva-16 is much steeper than in the corresponding zygotes that have not received chromosomal markers. In F′ strains which exhibit an increased frequency of transfer of chromosome markers, this gradient of recombination frequencies for merogenote markers is much steeper. An analysis of experiments involving an F′ strain with a much shorter F-merogenote, F16, and of a triparental mating in which F-merogenote and chromosome were transferred from different donor cells reveals that the effect of chromosome transfer on the recovery of distal F-merogenote markers in the zygotes is not due to any form of postzygotic elimination. It is suggested that, when F′ strains which are transferring F-merogenote begin to transfer chromosome, the latter event causes breakage of the F-merogenote. A second consequence of this interaction is a delay of 8 to 10 min in the first appearance of chromosomal markers in the zygotes. PMID:14047236

  9. Comprehensive expression analysis of pathogenicity genes in uropathogenic Escherichia coli strains.

    Science.gov (United States)

    Paniagua-Contreras, Gloria Luz; Hernández-Jaimes, Tania; Monroy-Pérez, Eric; Vaca-Paniagua, Felipe; Díaz-Velásquez, Clara; Uribe-García, Alina; Vaca, Sergio

    2017-02-01

    In this study, we investigated distinct expression patterns of genes encoding iron-acquisition systems, adhesins, protectins, and toxins in human uroepithelial cells infected with 194 uropathogenic Escherichia coli (UPEC) strains in vitro. We assessed the association of these genes with antibiotic resistance genes in this group of UPEC strains, previously characterised by polymerase chain reaction (PCR). Strains were isolated from patients with urinary tract infections (UTIs) from Unidad Médica Familiar de Salud Pública, located in Estado de México, México. Antibiotic resistance genes were identified by PCR, and the expression of virulence genes was detected by reverse-transcriptase-PCR after in vitro infection of cultured A431 human keratinocytes derived from a vulvar epidermoid carcinoma. The most frequently expressed virulence genotypes among the investigated UPEC strains included usp (68%), iha (64.9%), kpsMT (61.3%), fim (58.2%), irp2 (48.4), papC (33.5%), set (31.4%) and astA (30.9%), whereas the most frequently detected antibiotic resistance genes were tet(A) (34%), sul1 (31.4%) and TEM (26.3%). Furthermore, the most abundant pattern of gene expression (irp2/fim/iha/kpsMT/usp), associated with 8 different combinations of antibiotic resistance genotypes, was exhibited by 28 strains (14.4%). Taken together, these results indicate collective participation of distinct virulence UPEC genotypes during in vitro infection of cultured human epithelial cells, suggesting their potential involvement in UTI pathogenesis. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Frequency and organization of papA homologous DNA sequences among uropathogenic digalactoside-binding Escherichia coli strains.

    OpenAIRE

    Denich, K; Craiu, A; Rugo, H.; Muralidhar, G; O'Hanley, P.

    1991-01-01

    The frequency of selected papA DNA sequences among 89 digalactoside-binding, uropathogenic Escherichia coli strains was evaluated with 12 different synthetic 15-base probes corresponding to papA genes from four digalactoside-binding piliated recombinant strains (HU849, 201B, and 200A). The papA probes encode amino acids which are common at the carboxy terminus of all strains, adjacent to the proximal portion of the intramolecular disulfide loop of strain 210B, or predicted to constitute the t...

  11. Efficacy of an Escherichia coli O157:H7 SRP Vaccine in Orally Challenged Goats and Strain Persistence Over Time.

    Science.gov (United States)

    Swift, Jacob M; Foster, Derek M; Rogers, Anna T; Sylvester, Hannah J; Griffith, Emily H; Jacob, Megan E

    2017-03-01

    Small ruminants have been implicated in outbreaks of Escherichia coli O157:H7 at livestock exhibitions throughout the United States. Additionally, goat meat or milk may serve as a reservoir for foodborne transmission of the organism. These associations highlight the public health importance of an effective strategy to reduce E. coli O157:H7 shedding in goats. We examined the efficacy of the SRP® vaccine in goats orally challenged with E. coli O157:H7. Mixed-breed goats (n = 14) were randomly allocated into vaccinated and unvaccinated treatments (n = 7 per treatment). Goats were housed with a vaccinated and unvaccinated animal in each pen. Feces were collected for 3 weeks, then at necropsy, gastrointestinal contents were collected to determine the concentration of E. coli O157:H7. Three isolates per positive sample were saved and evaluated by pulsed-field gel electrophoresis (PFGE) to assess strain persistence over time. The mean concentration of E. coli O157:H7 in the feces of goats was numerically reduced in the vaccinated treatment; however, it was not statistically significant. In addition, the total number of days goats were fecal positive for E. coli O157:H7 were not different between vaccinated and unvaccinated treatments. Pulsotypes of isolates revealed that goats initially shed two of the four challenge strains of E. coli O157:H7, after which there was a distinct shift to two different strains. Further work is needed to evaluate cost-effective intervention strategies that reliably reduce E. coli O157:H7 shedding in goats, particularly those that may reduce the risk of transmission at public events, including petting zoos and fairs.

  12. A versatile Escherichia coli strain for identification of biotin transporters and for biotin quantification

    Science.gov (United States)

    Finkenwirth, Friedrich; Kirsch, Franziska; Eitinger, Thomas

    2014-01-01

    Biotin is an essential cofactor of carboxylase enzymes in all kingdoms of life. The vitamin is produced by many prokaryotes, certain fungi, and plants. Animals depend on biotin uptake from their diet and in humans lack of the vitamin is associated with serious disorders. Many aspects of biotin metabolism, uptake, and intracellular transport remain to be elucidated. In order to characterize the activity of novel biotin transporters by a sensitive assay, an Escherichia coli strain lacking both biotin synthesis and its endogenous high-affinity biotin importer was constructed. This strain requires artificially high biotin concentrations for growth. When only trace levels of biotin are available, it is viable only if equipped with a heterologous high-affinity biotin transporter. This feature was used to ascribe transport activity to members of the BioY protein family in previous work. Here we show that this strain together with its parent is also useful as a diagnostic tool for wide-concentration-range bioassays. PMID:24256712

  13. Genotyping of Campylobacter coli strains isolated in Brazil suggests possible contamination amongst environmental, human, animal and food sources.

    Science.gov (United States)

    Gomes, Carolina N; Souza, Roberto A; Passaglia, Jaqueline; Duque, Sheila S; Medeiros, Marta I C; Falcão, Juliana P

    2016-01-01

    Campylobacter coli and Campylobacter jejuni are two of the most common causative agents of food-borne gastroenteritis in numerous countries worldwide. In Brazil, campylobacteriosis is under diagnosed and under-reported, and few studies have molecularly characterized Campylobacter spp. in this country. The current study genotyped 63 C. coli strains isolated from humans (n512), animals (n521), food (n510) and the environment (n520) between 1995 and 2011 in Brazil. The strains were genotyped using pulsed-field gel electrophoresis (PFGE), sequencing the short variable region (SVR) of the flaA gene ( flaA-SVR) and high-resolution melting analysis (HRMA) of the clustered regularly interspaced short palindromic repeat (CRISPR) locus to better understand C. coli genotypic diversity and compare the suitability of these three methods for genotyping this species. Additionally, the discrimination index (DI) of each of these methods was assessed. Some C. coli strains isolated from clinical and non-clinical origins presented ≥80 % genotypic similarity by PFGE and flaA-SVR sequencing. HRMA of the CRISPR locus revealed only four different melting profiles. In total, 22 different flaA-SVR alleles were detected. Of these, seven alleles, comprising gt1647–gt1653, were classified as novel. The most frequent genotypes were gt30 and gt1647. This distribution reveals the diversity of selected Brazilian isolates in comparison with the alleles described in the PubMLST database. The DIs for PFGE, flaA–SVR sequencing and CRISPR-HRMA were 0.986, 0.916 and 0.550, respectively. PFGE and flaA-SVR sequencing were suitable for subtyping C. coli strains, in contrast to CRISPR-HRMA. The high genomic similarity amongst some C. coli strains confirms the hypothesis that environmental and food sources potentially lead to human and animal contamination in Brazil.

  14. Production of cytolethal distending toxin and other virulence characteristics of Escherichia coli strains of serogroup O86

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    Ghilardi Ângela Cristina Rodrigues

    2001-01-01

    Full Text Available Genetic and phenotypic virulence markers of different categories of diarrhoeagenic Escherichia coli were investigated in 106 strains of enteropathogenic E. coli (EPEC serogroup O86. The most frequent serotype found was O86:H34 (86%. Strains of this serotype and the non motile ones behaved as EPEC i.e., carried eae, bfpA and EAF DNA sequences and presented localised adherence to HeLa cells. Serotypes O86:H2, O86:H6, O86:H10, O86:H18, O86:H27 and O86:H non determined, belonged to other categories. The majority of the strains of serotype O86:H34 and non motile strains produced cytolethal-distending toxin (CDT. The ribotyping analysis showed a correlation among ribotypes, virulence markers and serotypes, thus suggesting that CDT production might be a property associated with a universal clone represented by the O86:H34 serotype.

  15. Conversion of xylan to ethanol by ethanologenic strains of Escherichia coli and Klebsiella oxytoca

    Energy Technology Data Exchange (ETDEWEB)

    Burchhardt, G.; Ingram, L.O. (Univ. of Florida, Gainesville (United States))

    1992-04-01

    A two-stage process was evaluated for the fermentation of polymeric feedstocks to ethanol by a single, genetically engineered microorganism. The truncated xylanase gene (xynZ) from the thermophilic bacterium Clostridium thermocellum was fused with the N terminus of lacZ to eliminate secretory signals. This hybrid gene was expressed at high levels in ethanologenic strains of Escherichia coli KO11 and Klebsiella oxytoca M5A1(pLOI555). Large amounts of xylanase (25 to 93 mU/mg of cell protein) accumulated as intracellular products during ethanol production. Cells containing xylanase for saccharification. After cooling, the hydrolysate was fermented to ethanol with the same organism (30C), thereby replenishing the supply of xylanase for a subsequent saccharification. Recombinant E. coli metabolized only xylose, while recombinant K. oxytoca M5A1 metabolized xylose, xylobiose, and xylotriose but not xylotetrose. Derivatives of this latter organism produced large amounts of intracellular xylosidase, and the organism is presumed to transport both xylobiose and xylotriose for intracellular hydrolysis. By using recombinant M5A1, approximately 34% of the maximal theoretical yield of ethanol was obtained from xylan by this two-stage process. The yield appeared to be limited by the digestability of commercial xylan rather than by a lack of sufficient xylanase or by ethanol toxicity. In general form, this two-stage process, which uses a single, genetically engineered microorganism, should be applicable for the production of useful chemicals from a wide range of biomass polymers.

  16. Multi drug resistance of campylobacter jejuni and campylobacter coli to tested antibiotics in strains originating from humans, poultry and swine

    Directory of Open Access Journals (Sweden)

    Tambur Zoran Ž.

    2010-01-01

    Full Text Available Thermophilic Campylobacter are among the most common cause of bacterial enteritis in humans. Food animals are considered one of the most important sources of Campylobacter causing infections in man. Campylobacter infection is clinically mild and resolves spontaneously. In severe or long-lasting cases, treatment with antibiotics is necessary. Resistance of Campylobacter spp. to drugs used in treatment of infection is a matter of concern. The aim of this paper is to determine presence of multi drug resistant strains of Campylobacter jejuni and Campylobacter coli isolated from animals and man. Material for testing was obtained by scraping the cecum surface from boilers, pig cecum and colon, and human feces. For isolation Campylobacter jejuni and Campylobacter coli microaerophilic conditions, temperature of 42°C and antibiotic supplement were required to inhibit the growth of other intestinal bacteria. In this research, for sensitivity testing of Campylobacter jejuni and Campylobacter coli three different methods were used: disc diffusion test, E-test, and dilution agar method. A total of 55 strains of Campylobacter jejuni and Campylobacter coli. Out of the total, 24 strains originated from man, 16 from broilers were isolated, and 15 from pigs. Multidrug resistance was determined in cases when the strains were resistant to two or more antibiotics. Applying E-test, we detected that the largest number of Campylobacter jejuni were multi drug resistant to two antibiotics (41.2%, and three antibiotics (11.8%. Applying disc diffusion method it was detected that 5.9% of Campylobacter jejuni from man was resistant to four tested antibiotics. Applying all three methods, it was detected that the largest number of Campylobacter strains was resistant to two antibiotics and three antibiotics. Applying disc diffusion method it was detected that 50% of Campylobacter coli strains from pigs were resistant to three tested antibiotics.

  17. Draft Genome Sequences of Escherichia coli Strains Isolated at Calving from the Uterus, Vagina, Vulva, and Rectoanal Junction of a Dairy Cow That Later Developed Metritis

    OpenAIRE

    Jeon, Soo Jin; Cunha, Federico; Ginn, Amber; Jeong, KwangCheol Casey; Galv?o, Klibs N.

    2017-01-01

    ABSTRACT Escherichia coli is involved in the pathogenicity of metritis in cows. We report here the genome sequences of E.?coli strains isolated at calving from the uterus, vagina, vulva, and rectoanal junction of a dairy cow that later developed metritis. The genomic similarities will give an insight into phylogenetic relationships among strains.

  18. Adherent-invasive Escherichia coli, strain LF82 disrupts apical junctional complexes in polarized epithelia

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    Ossa Juan C

    2009-08-01

    Full Text Available Abstract Background Although bacteria are implicated in the pathogenesis of chronic inflammatory bowel diseases (IBD, mechanisms of intestinal injury and immune activation remain unclear. Identification of adherent-invasive Escherichia coli (AIEC strains in IBD patients offers an opportunity to characterize the pathogenesis of microbial-induced intestinal inflammation in IBD. Previous studies have focused on the invasive phenotype of AIEC and the ability to replicate and survive in phagocytes. However, the precise mechanisms by which these newly identified microbes penetrate the epithelial lining remain to be clarified. Therefore, the aim of this study was to delineate the effects of AIEC, strain LF82 (serotype O83:H1 on model polarized epithelial monolayers as a contributor to intestinal injury in IBD. Results Infection of T84 and Madin-Darby Canine Kidney-I polarized epithelial cell monolayers with AIEC, strain LF82 led to a reduction in transepithelial electrical resistance and increased macromolecular (10 kilodalton dextran flux. Basolateral AIEC infection resulted in more severe disruption of the epithelial barrier. Increased permeability was accompanied by a redistribution of the tight junction adaptor protein, zonula occludens-1, demonstrated by confocal microscopy and formation of gaps between cells, as shown by transmission electron microscopy. After 4 h of infection of intestine 407 cells, bacteria replicated in the cell cytoplasm and were enclosed in membrane-bound vesicles positive for the late endosomal marker, LAMP1. Conclusion These findings indicate that AIEC, strain LF82 disrupts the integrity of the polarized epithelial cell barrier. This disruption enables bacteria to penetrate into the epithelium and replicate in the host cell cytoplasm. These findings provide important links between microbes related to IBD, the intestinal epithelial cell barrier and disease pathogenesis.

  19. Ensemble modeling for strain development of L-lysine-producing Escherichia coli.

    Science.gov (United States)

    Contador, Carolina A; Rizk, Matthew L; Asenjo, Juan A; Liao, James C

    2009-01-01

    One of the main strategies to improve the production of relevant metabolites has been the manipulation of single or multiple key genes in the metabolic pathways. This kind of strategy requires several rounds of experiments to identify enzymes that impact either yield or productivity. The use of mathematical tools to facilitate this process is desirable. In this work, we apply the Ensemble Modeling (EM) framework, which uses phenotypic data (effects of enzyme overexpression or genetic knockouts on the steady-state production rate) to screen for potential models capable of describe existing data and thus gaining insight to improve strains for l-lysine production. Described herein is a strategy to generate a set of kinetic models that describe a set of enzyme overexpression phenotypes previously determined in an Escherichia coli strain that produces increased levels of l-lysine in an industrial laboratory. This final ensemble of models captures the kinetic characteristics of the cell through screening of phenotypes after sequential overexpression of enzymes. Furthermore, these models demonstrate some predictive capability, as starting from the reference producing strain (overexpressing desensitized dihydrodipicolinate synthetase (dapA*)) this set of models is able to predict that the desensitization of aspartate kinase (lysC*) is the next rate-controlling step in the l-lysine pathway. Moreover, this set of models allows for the generation of further targets for testing, for example, phosphoenolpyruvate (Ppc), aspartate aminotransferase (AspC), and glutamate dehydrogenase (GdhA). This work demonstrates the usefulness, applicability, and scope that the Ensemble Modeling framework offers to build production strains.

  20. Apramycin treatment affects selection and spread of a multidrug-resistant Escherichia coli strain able to colonize the human gut in the intestinal microbiota of pigs

    DEFF Research Database (Denmark)

    Herrero-Fresno, Ana; Zachariasen, Camilla; Hansen, Monica Hegstad

    2016-01-01

    The effect of apramycin treatment on transfer and selection of an Escherichia coli strain (E. coli 912) in the intestine of pigs was analyzed through an in vivo experiment. The strain was sequenced and assigned to the sequence type ST101 and serotype O11. It carried resistance genes to apramycin/......-resistant E. coli. Since gentamicin is a first-choice drug for human bacteremia, this is of concern....

  1. Resistance to Antibiotics in Strains of Staphylococcus spp., Enterococcus spp. and Escherichia coli Isolated from Rectal Swabs of Pigs

    Directory of Open Access Journals (Sweden)

    M. Kolář

    2008-01-01

    Full Text Available The study aimed at determining the level of resistance of selected bacterial species (Staphylococcus spp., Enterococcus spp., Escherichia coli isolated from rectal swabs of pigs to antimicrobial agents. The tested strains were isolated from piglets aged 7 to 30 days. Bacterial species were identified by standard microbiological techniques and susceptibility to antibiotics was determined quantitatively by the standard microdilution method. Resistance of the Staphylococcus aureus strain to oxacillin was confirmed by detection of the mecA gene and PBP2a. A total of 115 Staphylococcus spp. isolates were collected. In the case of Staphylococcus aureus, the methicillin-resistant strain (MRSA was identified. Moreover, higher frequency of coagulase-negative staphylococci with minimum inhibitory concentration of oxacillin ≥ 0.5 mg/l was noticed. Inducible resistance to clindamycin in the Staphylococcus hominis strain was also detected. The strains of Enterococcus spp. (61 isolates exhibited high resistance to tetracycline (98.5%, erythromycin (86.8% and chloramphenicol (54.4%. Vancomycin-resistant enterococci were not isolated. In the case of Escherichia coli strains (111 isolates, higher frequency of resistant strains to tetracycline (81.1% and ampicillin (62.2% was documented. Resistance to fluoroquinolones and production of broad-spectrum β-lactamases was not noticed. The presented study may be considered as a pilot project assessing the prevalence of resistant bacteria in piglets kept on a single farm. It demonstrated the presence of resistant strains of Staphylococcus spp., including one MRSA strain, Enterococcus spp. and Escherichia coli. These strains may be present as a result of postnatal colonization with both bacterial microflora of dams and environmental microflora.

  2. Persistence of Pathogenic and Non-Pathogenic Escherichia coli Strains in Various Tropical Agricultural Soils of India.

    Directory of Open Access Journals (Sweden)

    S Naganandhini

    Full Text Available The persistence of Shiga-like toxin producing E. coli (STEC strains in the agricultural soil creates serious threat to human health through fresh vegetables growing on them. However, the survival of STEC strains in Indian tropical soils is not yet understood thoroughly. Additionally how the survival of STEC strain in soil diverges with non-pathogenic and genetically modified E. coli strains is also not yet assessed. Hence in the present study, the survival pattern of STEC strain (O157-TNAU was compared with non-pathogenic (MTCC433 and genetically modified (DH5α strains on different tropical agricultural soils and on a vegetable growing medium, cocopeat under controlled condition. The survival pattern clearly discriminated DH5α from MTCC433 and O157-TNAU, which had shorter life (40 days than those compared (60 days. Similarly, among the soils assessed, the red laterite and tropical latosol supported longer survival of O157-TNAU and MTCC433 as compared to wetland and black cotton soils. In cocopeat, O157 recorded significantly longer survival than other two strains. The survival data were successfully analyzed using Double-Weibull model and the modeling parameters were correlated with soil physico-chemical and biological properties using principal component analysis (PCA. The PCA of all the three strains revealed that pH, microbial biomass carbon, dehydrogenase activity and available N and P contents of the soil decided the survival of E. coli strains in those soils and cocopeat. The present research work suggests that the survival of O157 differs in tropical Indian soils due to varied physico-chemical and biological properties and the survival is much shorter than those reported in temperate soils. As the survival pattern of non-pathogenic strain, MTCC433 is similar to O157-TNAU in tropical soils, the former can be used as safe model organism for open field studies.

  3. Effect of solar radiation on multidrug resistant E. coli strains and antibiotic mixture photodegradation in wastewater polluted stream

    Energy Technology Data Exchange (ETDEWEB)

    Rizzo, L., E-mail: l.rizzo@unisa.it [Department of Civil Engineering, University of Salerno, via Ponte don Melillo, 1-84084 Fisciano (Italy); Fiorentino, A. [Department of Civil Engineering, University of Salerno, via Ponte don Melillo, 1-84084 Fisciano (Italy); Anselmo, A. [Pluriacque, via Alento, 84060 Prignano Cilento (Italy)

    2012-06-15

    The effect of solar radiation on the inactivation of multidrug resistant Escherichia coli (MDR) strains selected from an urban wastewater treatment plant (UWWTP) effluent and the change of their resistance to a mixture of three antibiotics (evaluated in terms of minimum inhibit concentration (MIC)) in wastewater polluted stream were investigated. The solar photodegradation of the mixture of the three target antibiotics (amoxicillin (AMX), ciprofloxacin (CPX), and sulfamethoxazole (SMZ)) was also evaluated. Additionally, since UWWTP effluents are possible sources of antibiotics and antibiotic resistant bacteria, the disinfection by conventional chlorination process of the UWWTP effluent inoculated with MDR strains was investigated too. Solar radiation poorly affected the inactivation of the two selected antibiotic resistant E. coli strains (40 and 60% after 180 min irradiation). Moreover, solar radiation did not affect strain resistance to AMX (MIC > 256 {mu}g/mL) and SMZ (MIC > 1024 {mu}g/mL), but affected resistance of the lower resistance strain to CPX (MIC decreased by 33% but only after 180 min of irradiation). Chlorination of wastewater sample strongly decreased the number of the two selected antibiotic resistant E. coli strains (99.667 and 99.999%), after 60 min of contact time at 2.0 mg/L initial chlorine concentration, but the resistance of survived colonies to antibiotics was unchanged. Finally, the solar photodegradation rate of the antibiotic mixture (1 mg/L initial concentration respectively) resulted in the following order (half-life time): CPX (t{sub 1/2} = 24 min) < AMX (t{sub 1/2} = 99 min) < SMZ (t{sub 1/2} = 577 min). Accordingly, the risk of the development of resistance to SMZ in surface water is significantly higher compared to CPX and AMX. - Highlights: Black-Right-Pointing-Pointer Solar radiation did not affect E. coli strain resistance to AMX and SMZ. Black-Right-Pointing-Pointer Solar radiation affected the resistance of one E. coli strain

  4. Draft Genome Sequence of Enterotoxigenic Escherichia coli Strain E24377A, Obtained from a Tribal Drinking Water Source in India.

    Science.gov (United States)

    Tamhankar, Ashok J; Nerkar, Sandeep S; Khadake, Prashant P; Akolkar, Dadasaheb B; Apurwa, Sachin R; Deshpande, Uday; Khedkar, Smita U; Stålsby-Lundborg, Cecilia

    2015-04-02

    Enterotoxigenic Escherichia coli (ETEC) is a major cause of diarrheal disease in humans and animals. Its dissemination can occur through water sources contaminated by it. Here, we report for the first time the draft genome sequence of ETEC strain E24377A, obtained from a tribal drinking water source in India. Copyright © 2015 Tamhankar et al.

  5. Draft Genome Sequence of Enterotoxigenic Escherichia coli Strain E24377A, Obtained from a Tribal Drinking Water Source in India

    OpenAIRE

    Tamhankar, Ashok J.; Nerkar, Sandeep S.; Khadake, Prashant P.; Akolkar, Dadasaheb B.; Apurwa, Sachin R.; Deshpande, Uday; Khedkar, Smita U.; St?lsby-Lundborg, Cecilia

    2015-01-01

    Enterotoxigenic Escherichia coli (ETEC) is a major cause of diarrheal disease in humans and animals. Its dissemination can occur through water sources contaminated by it. Here, we report for the first time the draft genome sequence of ETEC strain E24377A, obtained from a tribal drinking water source in India.

  6. Draft Genome Sequences of Two Avian Pathogenic Escherichia coli Strains of Clinical Importance, E44 and E51

    DEFF Research Database (Denmark)

    Ronco, Troels; Stegger, Marc; Andersen, Paal S

    2016-01-01

    Avian pathogenic Escherichia coli strains have remarkable impacts on animal welfare and the production economy in the poultry industry worldwide. Here, we present the draft genomes of two isolates from chickens (E44 and E51) obtained from field outbreaks and subsequently investigated...

  7. Simultaneous direct detection of Shiga-toxin producing Escherichia coli (STEC) strains by gold nanoparticle optical sensing

    Science.gov (United States)

    Shiga-toxin producing Escherichia coli (STEC) strains (“Big Six” – O26, O45, O103, O111, O121, O145, and O157) represent significant groups of pathogens responsible for foodborne diseases. The objective of this study was to develop a colorimetric optical sensing assay that can simultaneously detect ...

  8. Isolation and characterization of bacteriophages as potential agents against Shiga toxin – producing Escherichia coli (STEC) strains

    Science.gov (United States)

    Shiga – toxin producing Escherichia coli (STEC) is a significant group of foodborne pathogens that can cause mild diarrhea to serious human illnesses. The gastrointestinal tracts of cattle and other ruminants are the primary reservoirs of STEC strains and may co-harbor bacteriophages as part of its ...

  9. Gene expression analysis of E. coli strains provides insights into the role of gene regulation in diversification.

    Science.gov (United States)

    Vital, Marius; Chai, Benli; Østman, Bjørn; Cole, James; Konstantinidis, Konstantinos T; Tiedje, James M

    2015-05-01

    Escherichia coli spans a genetic continuum from enteric strains to several phylogenetically distinct, atypical lineages that are rare in humans, but more common in extra-intestinal environments. To investigate the link between gene regulation, phylogeny and diversification in this species, we analyzed global gene expression profiles of four strains representing distinct evolutionary lineages, including a well-studied laboratory strain, a typical commensal (enteric) strain and two environmental strains. RNA-Seq was employed to compare the whole transcriptomes of strains grown under batch, chemostat and starvation conditions. Highly differentially expressed genes showed a significantly lower nucleotide sequence identity compared with other genes, indicating that gene regulation and coding sequence conservation are directly connected. Overall, distances between the strains based on gene expression profiles were largely dependent on the culture condition and did not reflect phylogenetic relatedness. Expression differences of commonly shared genes (all four strains) and E. coli core genes were consistently smaller between strains characterized by more similar primary habitats. For instance, environmental strains exhibited increased expression of stress defense genes under carbon-limited growth and entered a more pronounced survival-like phenotype during starvation compared with other strains, which stayed more alert for substrate scavenging and catabolism during no-growth conditions. Since those environmental strains show similar genetic distance to each other and to the other two strains, these findings cannot be simply attributed to genetic relatedness but suggest physiological adaptations. Our study provides new insights into ecologically relevant gene-expression and underscores the role of (differential) gene regulation for the diversification of the model bacterial species.

  10. Distribution of Strain Type and Antimicrobial Susceptibility of Escherichia coli Isolates Causing Meningitis in a Large Urban Setting in Brazil

    Science.gov (United States)

    Berman, Hillary; Barberino, Maria Goreth; Moreira, Edson Duarte; Riley, Lee

    2014-01-01

    The clinical management of meningitis caused by Escherichia coli is greatly complicated when the organism becomes resistant to broad-spectrum antibiotics. We sought to characterize the antimicrobial susceptibilities, sequence types (ST), and presence of known drug resistance genes of E. coli isolates that caused meningitis between 1996 and 2011 in Salvador, Brazil. We then compared these findings to those for E. coli isolates from community-acquired urinary tract infections (UTI) that occurred during the same time period and in the same city. We found that 19% of E. coli isolates from cases of meningitis and less than 1% of isolates from UTI were resistant to third-generation cephalosporins. The sequence types of E. coli isolates from cases of meningitis included ST131, ST69, ST405, and ST62, which were also found among isolates from UTI. Additionally, among the E. coli isolates that were resistant to third-generation cephalosporins, we found genes that encode the extended-spectrum beta-lactamases CTX-M-2, CTX-M-14, and CTX-M-15. These observations demonstrate that compared to E. coli strains isolated from cases of community-acquired UTI, those isolated from cases of meningitis are more resistant to third-generation cephalosporins, even though the same sequence types are shared between the two forms of extraintestinal infections. PMID:24523478

  11. Distribution of strain type and antimicrobial susceptibility of Escherichia coli isolates causing meningitis in a large urban setting in Brazil.

    Science.gov (United States)

    Berman, Hillary; Barberino, Maria Goreth; Moreira, Edson Duarte; Riley, Lee; Reis, Joice N

    2014-05-01

    The clinical management of meningitis caused by Escherichia coli is greatly complicated when the organism becomes resistant to broad-spectrum antibiotics. We sought to characterize the antimicrobial susceptibilities, sequence types (ST), and presence of known drug resistance genes of E. coli isolates that caused meningitis between 1996 and 2011 in Salvador, Brazil. We then compared these findings to those for E. coli isolates from community-acquired urinary tract infections (UTI) that occurred during the same time period and in the same city. We found that 19% of E. coli isolates from cases of meningitis and less than 1% of isolates from UTI were resistant to third-generation cephalosporins. The sequence types of E. coli isolates from cases of meningitis included ST131, ST69, ST405, and ST62, which were also found among isolates from UTI. Additionally, among the E. coli isolates that were resistant to third-generation cephalosporins, we found genes that encode the extended-spectrum beta-lactamases CTX-M-2, CTX-M-14, and CTX-M-15. These observations demonstrate that compared to E. coli strains isolated from cases of community-acquired UTI, those isolated from cases of meningitis are more resistant to third-generation cephalosporins, even though the same sequence types are shared between the two forms of extraintestinal infections.

  12. Increased Expression of Periplasmic Cu,Zn Superoxide Dismutase Enhances Survival of Escherichia coli Invasive Strains within Nonphagocytic Cells

    Science.gov (United States)

    Battistoni, Andrea; Pacello, Francesca; Folcarelli, Silvia; Ajello, Maria; Donnarumma, Giovanna; Greco, Rita; Grazia Ammendolia, Maria; Touati, Danièle; Rotilio, Giuseppe; Valenti, Piera

    2000-01-01

    We have studied the influence of periplasmic Cu,Zn superoxide dismutase on the intracellular survival of Escherichia coli strains able to invade epithelial cells by the expression of the inv gene from Yersinia pseudotuberculosis but unable to multiply intracellularly. Intracellular viability assays, confirmed by electron microscopy observations, showed that invasive strains of E. coli engineered to increase Cu,Zn superoxide dismutase production are much more resistant to intracellular killing than strains containing only the chromosomal sodC copy. However, we have found only a slight difference in survival within HeLa cells between a sodC-null mutant and its isogenic wild-type strain. Such a small difference in survival correlates with the very low expression of this enzyme in the wild-type strain. We have also observed that acid- and oxidative stress-sensitive E. coli HB101(pRI203) is more rapidly killed in epithelial cells than E. coli GC4468(pRI203). The high mortality of E. coli HB101(pRI203), independent of the acidification of the endosome, is abolished by the overexpression of sodC. Our data suggest that oxyradicals are involved in the mechanisms of bacterial killing within epithelial cells and that high-level production of periplasmic Cu,Zn superoxide dismutase provides bacteria with an effective protection against oxidative damage. We propose that Cu,Zn superoxide dismutase could offer an important selective advantage in survival within host cells to bacteria expressing high levels of this enzyme. PMID:10603365

  13. Escherichia coli strains of phylogenetic group B2 and D and bacteriocin production are associated with advanced colorectal neoplasia.

    Science.gov (United States)

    Kohoutova, Darina; Smajs, David; Moravkova, Paula; Cyrany, Jiri; Moravkova, Monika; Forstlova, Miroslava; Cihak, Michal; Rejchrt, Stanislav; Bures, Jan

    2014-12-24

    Colorectal cancer (CRC) is the 3rd most common cancer worldwide and the Czech Republic has the 6th highest incidence of CRC worldwide. Large intestinal microbiota play in its etiopathogenesis important role. Bacteriocins are proteins, produced by bacteria from the Enterobacteriaceae family. The aim of our prospective study was to assess the colonization of large intestinal mucosa by Escherichia coli strains and to investigate their bacteriocin production. A total of 30 consecutive patients with colorectal adenoma, CRA (17 men, 13 women, aged 39-79, mean age 63 ± 9), 30 patients with CRC (23 men, 7 women, aged 38-86, mean age 67 ± 11) and 20 healthy controls (9 men, 11 women, age 23-84, mean age 55 ± 15) were enrolled into prospective study. Mucosal biopsies were taken in the caecum, transverse colon and rectum during pancolonoscopy. Microbiological culture, isolation and identification of bacteria followed. Bacteriocin production was assessed by growth inhibition of indicator strains E. coli K12-Row, E. coli C6 (phi), and Shigella sonnei 17. Identification of bacteriocin-encoding determinants and E. coli phylogroups was performed using PCR methods. A total of 622 strains were isolated and further investigated. A significantly higher frequency of simultaneous production of colicins and microcins was revealed in the group of patients with CRC, when compared to patients with CRA, p = 0.031. A significantly higher frequency of E. coli phylogroup D was found in patients with CRC, when compared to controls, p = 0.044. A significantly higher prevalence of bacteriocinogeny was confirmed in patients with advanced adenoma when compared to patients with non-advanced adenoma, p = 0.010. Increasing bacteriocinogeny was associated with an increasing stage of CRC (assessed according to TNM classification). Either E. coli phylogroup B2 or E. coli phylogroup D were isolated in biopsies of patients with right-sided CRC. A statistically higher incidence of

  14. Occurrence of Hybrid Escherichia coli Strains Carrying Shiga Toxin and Heat-Stable Toxin in Livestock of Bangladesh.

    Science.gov (United States)

    Johura, Fatema-Tuz; Parveen, Rozina; Islam, Atiqul; Sadique, Abdus; Rahim, Md Niaz; Monira, Shirajum; Khan, Anisur R; Ahsan, Sunjukta; Ohnishi, Makoto; Watanabe, Haruo; Chakraborty, Subhra; George, Christine M; Cravioto, Alejandro; Navarro, Armando; Hasan, Badrul; Alam, Munirul

    2016-01-01

    Shiga toxin-producing Escherichia coli (STEC) and enterotoxigenic E. coli (ETEC) are important causes of diarrhea in humans and animals worldwide. Although ruminant animals are the main source of STEC, diarrhea due to this pathotype is very low in Bangladesh where ETEC remains the predominant group associated with childhood diarrhea. In the present study, E. coli strains (n = 35) isolated from Bangladesh livestock (goats, sheep, and cattle) and poultry (chicken and ducks) were analyzed for the presence of major virulence factors, such as Shiga toxins (STX-1 and STX-2), heat-labile toxin, and heat-stable toxins (STa and STb). Multiplex polymerase chain reaction results revealed 23 (66%) E. coli strains to be virulent possessing either sta (n = 5), stx (stx1, n = 8; stx2, n = 2), or both (n = 8) genes in varying combinations. Thirty-four percent (8/23) of strains from livestock were hybrid type that carried both stx (either stx1 or stx2) and ETEC-specific enterotoxin gene sta. Serotyping results revealed that the ETEC strains belonged to five serotypes, namely O36:H5, O174:H-, O152:H8, O109:H51, and O8:H21, while the STEC-producing strains belonged to serotypes O76:H19 (n = 3), O43:H2 (n = 2), O87:H16 (n = 2), OR:H2 (n = 1), O110:H16 (n = 1), and O152:H8 (n = 1). The STEC-ETEC hybrid strains belonged to serotypes O76:H19 (n = 3), O43:H2 (n = 2), O87:H16, OR:H2, and O152:H8. Forty percent (2/5) of the ETEC and 20% (2/10) of the STEC strains were multidrug resistant with the highest drug resistance (50%) being found in the hybrid strains. Molecular fingerprinting determined by pulsed-field gel electrophoresis and cluster analyses by dendrogram revealed that, genetically, STEC-ETEC hybrid strains were highly heterogeneous. Multidrug-resistant E. coli STEC-ETEC hybrid strains in domesticated animals pose a public health threat for humans in Bangladesh.

  15. Computational Analysis of Host–Pathogen Protein Interactions between Humans and Different Strains of Enterohemorrhagic Escherichia coli

    Science.gov (United States)

    Bose, Tungadri; Venkatesh, K. V.; Mande, Sharmila S.

    2017-01-01

    Serotype O157:H7, an enterohemorrhagic Escherichia coli (EHEC), is known to cause gastrointestinal and systemic illnesses ranging from diarrhea and hemorrhagic colitis to potentially fatal hemolytic uremic syndrome. Specific genetic factors like ompA, nsrR, and LEE genes are known to play roles in EHEC pathogenesis. However, these factors are not specific to EHEC and their presence in several non-pathogenic strains indicates that additional factors are involved in pathogenicity. We propose a comprehensive effort to screen for such potential genetic elements, through investigation of biomolecular interactions between E. coli and their host. In this work, an in silico investigation of the protein–protein interactions (PPIs) between human cells and four EHEC strains (viz., EDL933, Sakai, EC4115, and TW14359) was performed in order to understand the virulence and host-colonization strategies of these strains. Potential host–pathogen interactions (HPIs) between human cells and the “non-pathogenic” E. coli strain MG1655 were also probed to evaluate whether and how the variations in the genomes could translate into altered virulence and host-colonization capabilities of the studied bacterial strains. Results indicate that a small subset of HPIs are unique to the studied pathogens and can be implicated in virulence. This subset of interactions involved E. coli proteins like YhdW, ChuT, EivG, and HlyA. These proteins have previously been reported to be involved in bacterial virulence. In addition, clear differences in lineage and clade-specific HPI profiles could be identified. Furthermore, available gene expression profiles of the HPI-proteins were utilized to estimate the proportion of proteins which may be involved in interactions. We hypothesized that a cumulative score of the ratios of bound:unbound proteins (involved in HPIs) would indicate the extent of colonization. Thus, we designed the Host Colonization Index (HCI) measure to determine the host

  16. Computational Analysis of Host-Pathogen Protein Interactions between Humans and Different Strains of EnterohemorrhagicEscherichia coli.

    Science.gov (United States)

    Bose, Tungadri; Venkatesh, K V; Mande, Sharmila S

    2017-01-01

    Serotype O157:H7, an enterohemorrhagic Escherichia coli (EHEC), is known to cause gastrointestinal and systemic illnesses ranging from diarrhea and hemorrhagic colitis to potentially fatal hemolytic uremic syndrome. Specific genetic factors like ompA, nsrR , and LEE genes are known to play roles in EHEC pathogenesis. However, these factors are not specific to EHEC and their presence in several non-pathogenic strains indicates that additional factors are involved in pathogenicity. We propose a comprehensive effort to screen for such potential genetic elements, through investigation of biomolecular interactions between E. coli and their host. In this work, an in silico investigation of the protein-protein interactions (PPIs) between human cells and four EHEC strains (viz., EDL933, Sakai, EC4115, and TW14359) was performed in order to understand the virulence and host-colonization strategies of these strains. Potential host-pathogen interactions (HPIs) between human cells and the "non-pathogenic" E. coli strain MG1655 were also probed to evaluate whether and how the variations in the genomes could translate into altered virulence and host-colonization capabilities of the studied bacterial strains. Results indicate that a small subset of HPIs are unique to the studied pathogens and can be implicated in virulence. This subset of interactions involved E. coli proteins like YhdW, ChuT, EivG, and HlyA. These proteins have previously been reported to be involved in bacterial virulence. In addition, clear differences in lineage and clade-specific HPI profiles could be identified. Furthermore, available gene expression profiles of the HPI-proteins were utilized to estimate the proportion of proteins which may be involved in interactions. We hypothesized that a cumulative score of the ratios of bound:unbound proteins (involved in HPIs) would indicate the extent of colonization. Thus, we designed the Host Colonization Index (HCI) measure to determine the host colonization

  17. Fate and Persistence of a Pathogenic NDM-1-Positive Escherichia coli Strain in Anaerobic and Aerobic Sludge Microcosms.

    Science.gov (United States)

    Mantilla-Calderon, David; Hong, Pei-Ying

    2017-07-01

    The presence of emerging biological pollutants in treated wastewater effluents has gained attention due to increased interest in water reuse. To evaluate the effectiveness of the removal of such contaminants by the conventional wastewater treatment process, the fate and decay kinetics of NDM-1-positive Escherichia coli strain PI7 and its plasmid-encoded antibiotic resistance genes (ARGs) were assessed in microcosms of anaerobic and aerobic sludge. Results showed that E. coli PI7 decayed at a significantly lower rate under anaerobic conditions. Approximate half-lives were 32.4 ± 1.4 h and 5.9 ± 0.9 h in the anaerobic and aerobic microcosms, respectively. In the aerobic microcosms, after 72 h of operation, E. coli PI7 remained detectable, but no further decay was observed. Instead, 1 in every 10,000 E. coli cells was identified to be recalcitrant to decay and persist indefinitely in the sludge. ARGs associated with the E. coli PI7 strain were detected to have transferred to other native microorganisms in the sludge or were released to the liquid fraction upon host decay. Extracellular DNA quickly degraded in the liquid fraction of the aerobic sludge. In contrast, no DNA decay was detected in the anaerobic sludge water matrix throughout the 24-h sampling period. This study suggests an increased likelihood of environmental dispersion of ARGs associated with anaerobically treated wastewater effluents and highlights the potential importance of persister cells in the dissemination of E. coli in the environment during reuse events of treated wastewater. IMPORTANCE This study examines the decay kinetics of a pathogenic and antibiotic resistant strain of Escherichia coli in microcosms simulating biological treatment units of aerobic and anaerobic sludge. The results of this study point at a significantly prolonged persistence of the E. coli and the associated antibiotic resistance gene in the anaerobic sludge. However, horizontal transfer of the plasmid encoding the

  18. Enhanced expression of recombinant beta toxin of Clostridium perfringens type B using a commercially available Escherichia coli strain.

    Science.gov (United States)

    Bakhshi, Fatemah; Pilehchian Langroudi, Reza; Eimani, Bahram Golestani

    2016-06-30

    Clostridium perfringens beta toxin is only produced by types B and C and plays an important role in many human and animal diseases, causing fatal conditions that originate in the intestines. We compared the expression of C. perfringens type B vaccine strain recombinant beta toxin gene in the Escherichia coli strains Rosetta(DE3) and BL21(DE3). The beta toxin gene was extracted from pJETβ and ligated with pET22b(+). pET22β was transformed into E. coli strains BL21(DE3) and Rosetta(DE3). Recombinant protein was expressed as a soluble protein after isopropyl β-D-1-thiogalactopyranoside (IPTG) induction in strain Rosetta(DE3) but not in BL21(DE3). Expression was optimised by growing recombinant cells at 37 °C and at an induction of 0.5 mM, 1 mM, 1.5 mM IPTG. Expression was evaluated using sodium dodecyl sulfate Polyacrylamide gel electrophoresis (SDS-PAGE). The recombinant protein was purified via Ni-NTA and was analysed using western blot. We concluded that E. coli strain RosettaTM(DE3) can enhance the expression of C. perfringens recombinant beta toxin.

  19. Enhanced expression of recombinant beta toxin of Clostridium perfringens type B using a commercially available Escherichia coli strain.

    Science.gov (United States)

    Bakhshi, Fatemah; Pilehchian Langroudi, Reza; Imani, Bahram Golestani

    2016-06-30

    Clostridium perfringens beta toxin is only produced by types B and C and plays an important role in many human and animal diseases, causing fatal conditions that originate in the intestines. We compared the expression of C. perfringens type B vaccine strain recombinant beta toxin gene in the Escherichia coli strains RosettaTM(DE3) and BL21(DE3). The beta toxin gene was extracted from pJETβ and ligated with pET22b(+). pET22β was transformed into E. coli strains BL21(DE3) and RosettaTM(DE3). Recombinant protein was expressed as a soluble protein after isopropyl β-D-1-thiogalactopyranoside (IPTG) induction in strain RosettaTM(DE3) but not in BL21(DE3). Expression was optimised by growing recombinant cells at 37 °C and at an induction of 0.5 mM, 1 mM, 1.5 mM IPTG. Expression was evaluated using sodium dodecyl sulfate Polyacrylamide gel electrophoresis (SDS-PAGE). The recombinant protein was purified via Ni-NTA and was analysed using western blot. We concluded that E. coli strain RosettaTM(DE3) can enhance the expression of C. perfringens recombinant beta toxin.

  20. Altered Regulation of Escherichia coli Biotin Biosynthesis in BirA Superrepressor Mutant Strains

    Science.gov (United States)

    Chakravartty, Vandana

    2012-01-01

    Transcription of the Escherichia coli biotin (bio) operon is directly regulated by the biotin protein ligase BirA, the enzyme that covalently attaches biotin to its cognate acceptor proteins. Binding of BirA to the bio operator requires dimerization of the protein, which is triggered by BirA-catalyzed synthesis of biotinoyl-adenylate (biotinoyl-5′-AMP), the obligatory intermediate of the ligation reaction. Although several aspects of this regulatory system are well understood, no BirA superrepressor mutant strains had been isolated. Such superrepressor BirA proteins would repress the biotin operon transcription in vivo at biotin concentrations well below those needed for repression by wild-type BirA. We isolated mutant strains having this phenotype by a combined selection-screening approach and resolved multiple mutations to give several birA superrepressor alleles, each having a single mutation, all of which showed repression dominant over that of the wild-type allele. All of these mutant strains repressed bio operon transcription in vivo at biotin concentrations that gave derepression of the wild-type strain and retained sufficient ligation activity for growth when overexpressed. All of the strains except that encoding G154D BirA showed derepression of bio operon transcription upon overproduction of a biotin-accepting protein. In BirA, G154D was a lethal mutation in single copy, and the purified protein was unable to transfer biotin from enzyme-bound biotinoyl-adenylate either to the natural acceptor protein or to a biotin-accepting peptide sequence. Consistent with the transcriptional repression data, each of the purified mutant proteins showed increased affinity for the biotin operator DNA in electrophoretic mobility shift assays. Surprisingly, although most of the mutations were located in the catalytic domain, all of those tested, except G154D BirA, had normal ligase activity. Most of the mutations that gave superrepressor phenotypes altered residues

  1. Molecular characterization of enterohemorrhagic Escherichia coli hemolysin gene (EHEC-hlyA)-harboring isolates from cattle reveals a diverse origin and hybrid diarrheagenic strains.

    Science.gov (United States)

    Askari Badouei, Mahdi; Morabito, Stefano; Najafifar, Arash; Mazandarani, Emad

    2016-04-01

    In the present study we investigated the occurrence of Escherichia coli strains harboring the gene encoding enterohemorrhagic E. coli hemolysin (EHEC-HlyA) in cattle and the association of this gene with various diarrheagenic E. coli (DEC) pathotypes. First, the bovine E. coli isolates were screened for EHEC-hlyA gene by PCR, and then they were characterized for the phylogenetic groups and the presence of the major virulence genes of different DEC pathotypes. In total, 25 virulence gene profiles were observed in 54 EHEC-hlyA+ isolates that reflect a considerable heterogeneity. The EHEC-hlyA+ strains were mostly associated with EHEC (72%), while only 7.4% were enteropathogenic E. coli (EPEC). We also showed the presence of estA gene of enterotoxigenic E. coli (ETEC) in 6 isolates (11.1%). Interestingly, two of the estA+ strains showed hybrid pathotypes with one carrying eae/estA (EPEC/ETEC), and the other one stx2/astA/estA (EHEC/ETEC). None of the isolates were related to enteroaggregative E. coli (EAggEC), enteroinvasive E. coli (EIEC), and necrotoxigenic E. coli (NTEC). The EHEC-plasmid encoded genes occurred in seven different combinations with EHEC-hlyA/saa/subA/espP being the most prevalent (46.3%). All stx-/eae+ strains carried O island 57 (OI-57) molecular marker(s) that may indicate these to be the progenitors of EHEC or strains losing stx. The most prevalent phylogroup was B1 (61.1%), but the most heterogeneous strains including the hybrid strains belonged to A phylogroup. Overall, our results indicate that cattle EHEC-hlyA encoding E. coli isolates consist of diverse diarrheagenic strains with the possible existence of hybrid pathotypes. Future studies are required to clarify the evolutionary aspects and clinical significance of these strains in humans and domestic animals. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. The Mobilome; A Major Contributor to Escherichia coli stx2-Positive O26:H11 Strains Intra-Serotype Diversity

    Science.gov (United States)

    Delannoy, Sabine; Mariani-Kurkdjian, Patricia; Webb, Hattie E.; Bonacorsi, Stephane; Fach, Patrick

    2017-01-01

    Shiga toxin-producing Escherichia coli of serotype O26:H11/H- constitute a diverse group of strains and several clones with distinct genetic characteristics have been identified and characterized. Whole genome sequencing was performed using Illumina and PacBio technologies on eight stx2-positive O26:H11 strains circulating in France. Comparative analyses of the whole genome of the stx2-positive O26:H11 strains indicate that several clones of EHEC O26:H11 are co-circulating in France. Phylogenetic analysis of the French strains together with stx2-positive and stx-negative E. coli O26:H11 genomes obtained from Genbank indicates the existence of four clonal complexes (SNP-CCs) separated in two distinct lineages, one of which comprises the “new French clone” (SNP-CC1) that appears genetically closely related to stx-negative attaching and effacing E. coli (AEEC) strains. Interestingly, the whole genome SNP (wgSNP) phylogeny is summarized in the cas gene phylogeny, and a simple qPCR assay targeting the CRISPR array specific to SNP-CC1 (SP_O26-E) can distinguish between the two main lineages. The PacBio sequencing allowed a detailed analysis of the mobile genetic elements (MGEs) of the strains. Numerous MGEs were identified in each strain, including a large number of prophages and up to four large plasmids, representing overall 8.7–19.8% of the total genome size. Analysis of the prophage pool of the strains shows a considerable diversity with a complex history of recombination. Each clonal complex (SNP-CC) is characterized by a unique set of plasmids and phages, including stx-prophages, suggesting evolution through separate acquisition events. Overall, the MGEs appear to play a major role in O26:H11 intra-serotype clonal diversification. PMID:28932209

  3. In-vitro activity of fosfomycin trometamol and some other antibiotics against Escherichia coli strains isolated from urinary tract infections

    Directory of Open Access Journals (Sweden)

    Alicem Tekin

    2011-09-01

    Full Text Available Objectives: In recent years, in our country and the world, susceptibility of uropathogenic E.coli strains to commonly used antibiotics in the treatment of urinary tract infections has decreased. That decreased susceptibility has been caused to treatment failure, need to change the empirical treatment, increase in prescription costs, prolongation of hospital stay, increased social costs, increased morbidity and mortality. In this study, determination of susceptibility to different variety of antibiotics and fosfomycin in urinary tract infection isolate E.coli were aimed.Materials and methods: The study included E.coli positive urine samples which had been sent to State Hospital Central Laboratory in Kızıltepe between August 2010 and December 2010. These isolates were obtained from patients who have microscopically 10/mm3 leukocyte in urine. In this study, we tested susceptibility of isolated E.coli to FOT (Fosfomycin, CIP(ciprofloxacin, IP (İmipenem, TZP (Piperasilin-Tazobactam, CAZ (Ceftazidim. According to CLSI criteria, susceptibility testing was performed by Kirby-Bauer disc diffusion method.Results: E.coli strains isolated from urine samples examined between August 2010 and December 2010, all were susceptible to fosfomisine. The resistance rates of E.coli strains to Ceftazidim, Ciprofloxacin, İmipenem, Piperacillin-Tazobactam were found respectively 33.3%, 49.1%, 36.8%, 45.6% (Table 1.Conclusions: Because of the high susceptibility rates of fosfomycin at community-acquired urinary tract infection, it can be preferred to the non-complicated urinary tract infections as an antimicrobial agent.

  4. Rapid MALDI-TOF Mass Spectrometry Strain Typing during a Large Outbreak of Shiga-Toxigenic Escherichia coli

    Science.gov (United States)

    Christner, Martin; Trusch, Maria; Rohde, Holger; Kwiatkowski, Marcel; Schlüter, Hartmut; Wolters, Manuel; Aepfelbacher, Martin; Hentschke, Moritz

    2014-01-01

    Background In 2011 northern Germany experienced a large outbreak of Shiga-Toxigenic Escherichia coli O104:H4. The large amount of samples sent to microbiology laboratories for epidemiological assessment highlighted the importance of fast and inexpensive typing procedures. We have therefore evaluated the applicability of a MALDI-TOF mass spectrometry based strategy for outbreak strain identification. Methods Specific peaks in the outbreak strain’s spectrum were identified by comparative analysis of archived pre-outbreak spectra that had been acquired for routine species-level identification. Proteins underlying these discriminatory peaks were identified by liquid chromatography tandem mass spectrometry and validated against publicly available databases. The resulting typing scheme was evaluated against PCR genotyping with 294 E. coli isolates from clinical samples collected during the outbreak. Results Comparative spectrum analysis revealed two characteristic peaks at m/z 6711 and m/z 10883. The underlying proteins were found to be of low prevalence among genome sequenced E. coli strains. Marker peak detection correctly classified 292 of 293 study isolates, including all 104 outbreak isolates. Conclusions MALDI-TOF mass spectrometry allowed for reliable outbreak strain identification during a large outbreak of Shiga-Toxigenic E. coli. The applied typing strategy could probably be adapted to other typing tasks and might facilitate epidemiological surveys as part of the routine pathogen identification workflow. PMID:25003758

  5. ISOLASI STREPTOMYCES SPP. PADA KAWASAN HUTAN PROVINSI BALI SERTA UJI DAYA HAMBATNYA TERHADAP LIMA STRAIN DIARRHEAGENIC ESCHERICHIA COLI

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    I WAYAN EKA DHARMAWAN

    2014-04-01

    Full Text Available An exploration study of natural resources soil bacteria antibiotic-producer, Streptomyces spp. was done in two steps. The first step was isolation of Streptomyces and the second involved testing their inhibition activities against five strains diarrheagenic Escherichia coli. Soil samples were collected from ten forest areas in Bali. As many as 55 isolates were collected with various macroscopic dan microscopic characters. Most isolates (eight Streptomyces isolates were collected from forest area in Penulisan, Kintamani (RTK. 20. The diversities of isolates are influenced by environment condition. All Streptomyces isolated were tested against five strains diarrheagenic Escherichia coli to check antibiotic activity for inhibit growth of E. coli. Streptomycine was used as a control. The result showed that the largest inhibition zones of Streptomyces against E. coli strains EHEC, ETEC, EIEC, EPEC and DAEC were produced by Streptomyces PK5 (48,67 ± 0,58 mm, Streptomyces GAA4 (29,00 ± 2,00 mm, Streptomyces GBK3 (42,67 ± 2,08 mm, Streptomyces SkBB5 (29,00 ± 2,65 mm and Streptomyces GM3 (33,67 ± 3,21 mm respectively.

  6. Photoreactivation and dark repair of environmental E. coli strains following 24 kHz continuous ultrasound and UV-C irradiation.

    Science.gov (United States)

    Kaur, Jasjeet; Karthikeyan, Raghupathy; Pillai, Suresh D

    2016-07-02

    In this study, effects of 24 kHz continuous ultrasound and UV-C on inactivation and potential repair of environmental E. coli strains were studied through a culture based method and a metabolic activity assay. Three environmental E. coli strains isolated from fecal samples of feral hog and deer and treated wastewater effluent were studied and compared with a laboratory E. coli strain (ATCC® 10798). Metabolic activity of E. coli cells during the inactivation and repair period was assessed using the AlamarBlue® assay. Transmission electron microscopy assays were also performed to evaluate morphological damage of bacterial cell wall. After 24 h of photoreactivation period, laboratory E. coli strain (ATCC® 10798) reactivated by 30% and 42% in contrast to E. coli isolate from treated wastewater effluent, which reactivated by 53% and 82% after ultrasound and UV-C treatment, respectively. Possible shearing and reduction in cell size of E. coli strains exposed to ultrasound was revealed by transmission electron micrographs. Metabolic activity of E. coli strains was greatly reduced due to morphological damage to cell membrane caused by 24 kHz continuous ultrasound. Based upon experimental data and TEM micrographs, it could be concluded that ultrasound irradiation has potential in advanced water treatment and water reuse applications.

  7. D-Alanine-Controlled Transient Intestinal Mono-Colonization with Non-Laboratory-Adapted Commensal E. coli Strain HS.

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    Miguelangel Cuenca

    Full Text Available Soon after birth the mammalian gut microbiota forms a permanent and collectively highly resilient consortium. There is currently no robust method for re-deriving an already microbially colonized individual again-germ-free. We previously developed the in vivo growth-incompetent E. coli K-12 strain HA107 that is auxotrophic for the peptidoglycan components D-alanine (D-Ala and meso-diaminopimelic acid (Dap and can be used to transiently associate germ-free animals with live bacteria, without permanent loss of germ-free status. Here we describe the translation of this experimental model from the laboratory-adapted E. coli K-12 prototype to the better gut-adapted commensal strain E. coli HS. In this genetic background it was necessary to complete the D-Ala auxotrophy phenotype by additional knockout of the hypothetical third alanine racemase metC. Cells of the resulting fully auxotrophic strain assembled a peptidoglycan cell wall of normal composition, as long as provided with D-Ala and Dap in the medium, but could not proliferate a single time after D-Ala/Dap removal. Yet, unsupplemented bacteria remained active and were able to complete their cell cycle with fully sustained motility until immediately before autolytic death. Also in vivo, the transiently colonizing bacteria retained their ability to stimulate a live-bacteria-specific intestinal Immunoglobulin (IgA response. Full D-Ala auxotrophy enabled rapid recovery to again-germ-free status. E. coli HS has emerged from human studies and genomic analyses as a paradigm of benign intestinal commensal E. coli strains. Its reversibly colonizing derivative may provide a versatile research tool for mucosal bacterial conditioning or compound delivery without permanent colonization.

  8. Metabolic regulation analysis of an ethanologenic Escherichia coli strain based on RT-PCR and enzymatic activities

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    Martinez Alfredo

    2008-05-01

    Full Text Available Abstract Background A metabolic regulation study was performed, based upon measurements of enzymatic activities, fermentation performance, and RT-PCR analysis of pathways related to central carbon metabolism, in an ethanologenic Escherichia coli strain (CCE14 derived from lineage C. In comparison with previous engineered strains, this E coli derivative has a higher ethanol production rate in mineral medium, as a result of the elevated heterologous expression of the chromosomally integrated genes encoding PDCZm and ADHZm (pyruvate decarboxylase and alcohol dehydrogenase from Zymomonas mobilis. It is suggested that this behavior might be due to lineage differences between E. coli W and C. Results This study demonstrated that the glycolytic flux is controlled, in this case, by reactions outside glycolysis, i.e., the fermentative pathways. Changes in ethanol production rate in this ethanologenic strain result in low organic acid production rates, and high glycolytic and ethanologenic fluxes, that correlate with enhanced transcription and enzymatic activity levels of PDCZm and ADHZm. Furthermore, a higher ethanol yield (90% of the theoretical in glucose-mineral media was obtained with CCE14 in comparison with previous engineered E. coli strains, such as KO11, that produces a 70% yield under the same conditions. Conclusion Results suggest that a higher ethanol formation rate, caused by ahigher PDCZm and ADHZm activities induces a metabolic state that cells compensate through enhanced glucose transport, ATP synthesis, and NAD-NADH+H turnover rates. These results show that glycolytic enzymatic activities, present in E. coli W and C under fermentative conditions, are sufficient to contend with increases in glucose consumption and product formation rates.

  9. Vanillin production by recombinant strains of Escherichia coli Produção de vanilina por linhagens recombinantes de Escherichia coli

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    Attilio Converti

    2003-11-01

    Full Text Available Vanillin production from ferulate was studied using different recombinant strains of Escherichia coli. To prevent the occurrence of aerobic conditions and then possible product oxidation, tests were performed in Erlenmeyer flasks under mild mixing (150 rpm. Among other transformants, E. coli JM109(pBB1 appeared to be the best vanillin producer, being able to convert no less than 95% of starting ferulate to the product within 1h. This yield decreased down to 72% after 72h, likely because of a non-specific oxidase activity responsible for vanillin oxidation to vanillate.A produção de vanilina a partir de ácido ferúlico foi estudada utilizando-se diferentes linhagens recombinantes de Escherichia coli. Para prevenir a ocorrência de condições de aerobiose e a possível oxidação do produto, os ensaios foram realizados em frascos Erlenmeyer sob agitação moderada (150 rpm. E. coli JM109 (pBBI mostrou-se o melhor produtor de vanilina entre os demais agentes transformantes, sendo capaz de converter 95% do ácido ferúlico inicial em produto após 1h, rendimento este que decresceu para 72% após 72h, provavelmente devido à atividade de uma oxidase não-específica responsável pela oxidação de vanilina a ácido vanílico.

  10. THE WIDESPREAD OCCURRENCE OF THE ENTEROHEMOLYSIN GENE EHLYA AMONG ENVIRONMENTAL STRAINS OF ESCHERICHIA COLI

    Science.gov (United States)

    The putative virulence factor enterohemolysin, encoded for by the ehlyA gene, has been closely associated with the pathogenic enterohemorrhagic Escherichia coli (EHEC) group. E. coli isolates from effluents from seven geographically dispersed municipal ...

  11. Dissemination of cephalosporin resistance genes between Escherichia coli strains from farm animals and humans by specific plasmid lineages.

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    Mark de Been

    2014-12-01

    Full Text Available Third-generation cephalosporins are a class of β-lactam antibiotics that are often used for the treatment of human infections caused by Gram-negative bacteria, especially Escherichia coli. Worryingly, the incidence of human infections caused by third-generation cephalosporin-resistant E. coli is increasing worldwide. Recent studies have suggested that these E. coli strains, and their antibiotic resistance genes, can spread from food-producing animals, via the food-chain, to humans. However, these studies used traditional typing methods, which may not have provided sufficient resolution to reliably assess the relatedness of these strains. We therefore used whole-genome sequencing (WGS to study the relatedness of cephalosporin-resistant E. coli from humans, chicken meat, poultry and pigs. One strain collection included pairs of human and poultry-associated strains that had previously been considered to be identical based on Multi-Locus Sequence Typing, plasmid typing and antibiotic resistance gene sequencing. The second collection included isolates from farmers and their pigs. WGS analysis revealed considerable heterogeneity between human and poultry-associated isolates. The most closely related pairs of strains from both sources carried 1263 Single-Nucleotide Polymorphisms (SNPs per Mbp core genome. In contrast, epidemiologically linked strains from humans and pigs differed by only 1.8 SNPs per Mbp core genome. WGS-based plasmid reconstructions revealed three distinct plasmid lineages (IncI1- and IncK-type that carried cephalosporin resistance genes of the Extended-Spectrum Beta-Lactamase (ESBL- and AmpC-types. The plasmid backbones within each lineage were virtually identical and were shared by genetically unrelated human and animal isolates. Plasmid reconstructions from short-read sequencing data were validated by long-read DNA sequencing for two strains. Our findings failed to demonstrate evidence for recent clonal transmission of

  12. Fate and persistence of a pathogenic NDM-1-positive Escherichia coli strain in anaerobic and aerobic sludge microcosms

    KAUST Repository

    Mantilla-Calderon, David

    2017-04-15

    The presence of emerging biological pollutants in treated wastewater effluents has gained attention due to increased interest in water reuse. To evaluate the effectiveness of the removal of such contaminants by the conventional wastewater treatment process, the fate and decay kinetics of NDM-1-positive Escherichia coli strain PI7 and its plasmid-encoded antibiotic resistance genes (ARGs) were assessed in microcosms of anaerobic and aerobic sludge. Results showed that E. coli PI7 decayed at a significantly slower rate under anaerobic conditions. Approximate half-lives were 32.4 ± 1.4 h and 5.9 ± 0.9 h in the anaerobic and aerobic microcosms, respectively. In the aerobic microcosms, after 72 h of operation, E. coli PI7 remained detectable but no further decay was observed. Instead, 1 in every 10000 E. coli cells was identified to be recalcitrant to decay and persist indefinitely in the sludge. ARGs associated with the E. coli PI7 were detected to have transferred to other native microorganisms in the sludge, or are released to the liquid fraction upon host decay. Extracellular DNA quickly degraded in the liquid fraction of the aerobic sludge. In contrast, no DNA decay was detected in the anaerobic sludge water matrix throughout the 24 h sampling period. This study suggests an increased likelihood of environmental dispersion of ARGs associated with anaerobically treated wastewater effluents and highlights the potential importance of persister cells in the dissemination of E. coli in the environment during reuse events of treated wastewater.IMPORTANCE This study examines the decay kinetics of a pathogenic and antibiotic resistant strain of Escherichia coli in microcosms simulating biological treatment units of aerobic and anaerobic sludge. The results of this study points at a significantly prolonged persistence of the E. coli and the associated antibiotic resistance gene in the anaerobic sludge. However, horizontal transfer of the plasmid encoding the antibiotic

  13. Engineering of a microbial coculture of Escherichia coli strains for the biosynthesis of resveratrol.

    Science.gov (United States)

    Camacho-Zaragoza, José M; Hernández-Chávez, Georgina; Moreno-Avitia, Fabian; Ramírez-Iñiguez, René; Martínez, Alfredo; Bolívar, Francisco; Gosset, Guillermo

    2016-09-29

    Resveratrol is a plant natural product with many health-protecting effects which makes it an attractive chemical both for academic studies and industrial purposes. However, the low quantities naturally produced by plants as well as the unsustainable procedures of extraction, purification and concentration have prompted many biotechnological approaches to produce this chemical in large quantities from renewable sources. None of these approaches have considered a microbial coculture strategy to produce this compound. The aim of this study was to prove the functionality of a microbial coculture for the biosynthesis of resveratrol. In this work, we have successfully applied a coculture system strategy comprised of two populations of Escherichia coli strains, each with a partial and complementary section of the pathway leading to the biosynthesis of the stilbene resveratrol. The first strain is a pheA knockout mutant previously engineered to excrete p-coumaric acid into the medium through the overexpression of genes encoding a tyrosine ammonia lyase from Rhodothorula glutinis, a feedback resistant 3-deoxy-D-arabino-heptulosonate 7-phosphate synthase and a transketolase. The second strain in the coculture was engineered to express the second part of the resveratrol biosynthetic pathway through the introduction of synthetic genes encoding the 4-coumaroyl-CoA ligase from Streptomyces coelicolor A2 and the stilbene synthase either from the peanut Arachis hypogaea or the grapevine Vitis vinifera, the latter synthesized employing a gene harmonization strategy and showing better resveratrol production performance. Batch cultures were performed in mineral medium with glycerol as the sole carbon source, where a final titer of 22.6 mg/L of resveratrol was produced in 30 h. To our knowledge, this is the first time that a coculture of bacterial strains is used for the biosynthesis of resveratrol from glycerol, having the potential for a greater improvement in the product yield

  14. Frequency of Extended-Spectrum Beta-lactamases (ESBLs) in strains of Klebsiella and E. coli isolated from patients hospitalized in Yazd.

    Science.gov (United States)

    Zandi, Hengameh; Tabatabaei, Seyed Mostafa; Ehsani, Fatemeh; Zarch, Mojtaba Babaei; Doosthosseini, Samira

    2017-02-01

    Frequency of extended-spectrum beta-lactamases (ESBLs) and its variants may vary in different geographical areas, as reports indicate their spread in some certain communities. The aim of this study was to determine the frequency of ESBLs in strains of Klebsiella and E. coli, isolated from patients hospitalized in teaching hospitals of Yazd. This cross-sectional study was carried out on samples including E. coli and Klebsiella strains collected from laboratories of Shahid Sadoughi and Shahid Rahnemoun hospitals in Yazd, Iran in the period of 2011-2012. The colonies which were positive in lactose Eosin methylene-blue (EMB) medium were identified by biochemical methods, and 270 strains of Klebsiella and E. coli were isolated. Collected data and information were analyzed using Fisher's exact test and descriptive statistics such as mean in SPSS software, version 15, at a significant level of 0.05. In this study, 270 samples were examined, including 152 samples of E. coli (56.3%) and 118 samples of Klebsiella pneumonia (43.7%). Among the 152 samples of E. coli, 45 strains (30%) were producers of ESBLs. In addition, among the 118 samples of Klebsiella pneumonia, 44 strains (37.3%) were producers of ESBLs. E. coli strains showed the most resistance to Cefotaxime (100%), Ceftazidime (97.7%), and Cefepime (75.5%) respectively and Klebsiella strains showed the most resistance to Cefotaxime (100%), Ceftazidime (100%) and Cefepime (79.5%), respectively. Frequency of ESBLs in Klebsiella strains was higher than E. coli strains. No significant relationship was found between frequency of ESBLs and age or gender. In addition, E. coli strains showed the highest sensitivity to Imipenem, Amoxicillin/clavulanate, and Ciprofloxacin, while the highest antibiotic sensitivity of Klebsiella strains was shown to be to Piperacillin, Imipenem, and Amoxicillin/clavulanate.

  15. Towards understanding inter-strain attachment variations of Escherichia coli during transport in saturated quartz sand.

    NARCIS (Netherlands)

    Foppen, J.W.; Lutterodt, G.; Roling, W.F.M.; Uhlenbrook, S.

    2010-01-01

    Although Escherichia coli is an indicator of fecal contamination in aquifers, limited research has been devoted to understanding the biological processes involved in the initial attachment of E. coli transported in abiotic porous media. The roles of the various surface structures of E. coli, like

  16. DETECTION OF STX2 COLIPHAGES IN STRAIN OF ESCHERICHIA COLI ISOLATED FROM BOVINE FLEECE AND MILK FILTERS

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    G. Delle Donne

    2011-01-01

    Full Text Available Lambda(4-phage vectors of gene codifying for synthesis of Shiga-toxins are suspected to be involved in the virulence evolution of Vero-Toxin producing Escherichia coli(VTEC. Herds of domestic or wild ruminants are reservoirs of these bacteria, but excretion with faeces is more frequent in groups of heifers and feeder calves. Studies have shown that slurries produced by infected herds are often positive for VTEC and that Stx2 carrying lambda coliphages can be isolated. These viruses can induce lysogenic cycles only in some strain of Escherichia coli and the Stx gene is then integrated in the bacterial chromosome. When these bacteria also posses other virulence traits, like those responsible for the intimate attachment to the enteric mucosal cells (eae or saa the recombinant strains might became pathogen for humans. Our research was aimed at detecting the coliphages form ten Stx2 positive strains isolated in our previous studies. We have included strains, possessing or not the ‘eae’ genes. In addition we have used other isolates originating from slaughterhouses, with the aim of evaluating their susceptibility to the isolated 4-phages. Following induction of a lytic cycle with mitomycin C, the strains were screened by hybridization of plaque blots with Stx2 probes. The purified extracts of eight of the ten strains produced plaque/halos of lysis in cultures of susceptible strains, thus showing these strains were infected by inducible phages, but only one proved to be Stx2 carrier. Attempt to obtain new lysogens using the purified Stx2 phage with other strains ‘eae’ positive and STx negative isolated from slaughterhouses were unsuccessful. Stx2 lysogens were obtained only using the reference strains DM1187.

  17. The virulence factor ychO has a pleiotropic action in an Avian Pathogenic Escherichia coli (APEC) strain.

    Science.gov (United States)

    Pilatti, Livia; Boldrin de Paiva, Jacqueline; Rojas, Thaís Cabrera Galvão; Leite, Janaína Luisa; Conceição, Rogério Arcuri; Nakazato, Gerson; Dias da Silveira, Wanderley

    2016-03-10

    Avian pathogenic Escherichia coli strains cause extraintestinal diseases in birds, leading to substantial economic losses to the poultry industry worldwide. Bacteria that invade cells can overcome the host humoral immune response, resulting in a higher pathogenicity potential. Invasins are members of a large family of outer membrane proteins that allow pathogen invasion into host cells by interacting with specific receptors on the cell surface. An in silico analysis of the genome of a septicemic APEC strain (SEPT362) demonstrated the presence of a putative invasin homologous to the ychO gene from E. coli str. K-12 substr. MG1655. In vitro and in vivo assays comparing a mutant strain carrying a null mutation of this gene, a complemented strain, and its counterpart wild-type strain showed that ychO plays a role in the pathogenicity of APEC strain SEPT362. In vitro assays demonstrated that the mutant strain exhibited significant decreases in bacterial adhesiveness and invasiveness in chicken cells and biofilm formation. In vivo assay indicated a decrease in pathogenicity of the mutant strain. Moreover, transcriptome analysis demonstrated that the ychO deletion affected the expression of 426 genes. Among the altered genes, 93.66% were downregulated in the mutant, including membrane proteins and metabolism genes. The results led us to propose that gene ychO contributes to the pathogenicity of APEC strain SEPT362 influencing, in a pleiotropic manner, many biological characteristics, such as adhesion and invasion of in vitro cultured cells, biofilm formation and motility, which could be due to the possible membrane location of this protein. All of these results suggest that the absence of gene ychO would influence the virulence of the APEC strain herein studied.

  18. Asymptomatic bacteriuria Escherichia coli strain 83972 carries mutations in the foc locus and is unable to express F1C fimbriae

    DEFF Research Database (Denmark)

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

    2006-01-01

    adhesion conferred by specific surface-associated adhesins is normally considered as a prerequisite for colonization of the urinary tract. The prototype ABU E. coli strain 83972 was originally isolated from a girl who had carried it asymptomatically for 3 years. This study characterized the molecular......Escherichia coli is the most common organism associated with asymptomatic bacteriuria (ABU). In contrast to uropathogenic E. coli (UPEC), which causes symptomatic urinary tract infection (UTI), very little is known about the mechanisms by which these strains colonize the urinary tract. Bacterial...... this adhesin. The data imply that E. coli 83972 has lost its ability to express this important colonization factor as a result of host-driven evolution. The ancestor of the strain seems to have been a pyelonephritis strain of phylogenetic group B2. Strain 83972 therefore represents an example of bacterial...

  19. Succinate overproduction: A case study of computational strain design using a comprehensive Escherichia coli kinetic model

    Directory of Open Access Journals (Sweden)

    Ali eKhodayari

    2015-01-01

    Full Text Available Computational strain design prediction accuracy has been the focus for many recent efforts through the selective integration of kinetic information into metabolic models. In general, kinetic model prediction quality is determined by the range and scope of genetic and/or environmental perturbations used during parameterization. In this effort, we apply the k-OptForce procedure on a kinetic model of E. coli core metabolism constructed using the Ensemble Modeling (EM method and parameterized using multiple mutant strains data under aerobic respiration with glucose as the carbon source. Minimal interventions are identified that improve succinate yield under both aerobic and anaerobic conditions to test the fidelity of model predictions under both genetic and environmental perturbations. Under aerobic condition, k-OptForce identifies interventions that match existing experimental strategies pointing at a number of unexplored flux redirections such as routing glyoxylate flux through the glycerate metabolism to improve succinate yield. Many of the identified interventions rely on the kinetic descriptions and would not be discoverable by a purely stoichiometric description. In contrast, under fermentative (anaerobic conditions, k-OptForce fails to identify key interventions including up-regulation of anaplerotic reactions and elimination of competitive fermentative products. This is due to the fact that the pathways activated under anaerobic conditions were not properly parameterized as only aerobic flux data were used in the model construction. This study shed light on the importance of condition-specific model parameterization and provides insight onto how to augment kinetic models so as to correctly respond to multiple environmental perturbations.

  20. Surface topological differences of phage infected uropathogenic Escherichia coli (UPEC) strains, revealed by atomic force microscopy.

    Science.gov (United States)

    Hanif, Bassamah; Jamil, Nusrat; Shah, Muhammad Raza

    2016-01-01

    Atomic force microscopy (AFM) is an advance microscopic technique that provides three dimensional structures of cell surfaces with high resolution. In the present study AFM was used for comparative analysis of surface topology of phage infected and uninfected Uropathogenic Escherichia coli (UPEC) cells. Two UPEC strains NE and HN were isolated from urine samples of Urinary tract infection patients and their specific narrow host range lytic phages 3S and HNΦ were isolated from the sewage of different areas. On the basis of one step growth curve both phages characterized as short latent period phages with latency period of about 30 min. On AFM analysis significant difference in topology of healthy and infected cells were observed. It was hypothesized that progeny of both lytic phages released out from their respective host cells in different manner. The image of 3S infected UPEC host cells (NE) revealed multiple internal projections which showed progeny phages released out from host cells through these multiple sites. Whereas images of HNΦ infected HN host cells showed central depression which illustrated that new phages released out through single exit point from the middle of cell. These results are significant to extend future studies on isolated phages as an effective tool for phage therapy.

  1. Antibiotic Resistance in Escherichia Coli Strains Isolated from Urine of Inpatients and Outpatients

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    Abolfazl Davoodabadi

    2012-08-01

    Full Text Available The urinary tract infections regarded as a health problem around the world and not only as an agent of nosocomial infections but also infections in the community. Community acquired UTIs cause significant illness in the first 2 years of life [1]. Urinary tract infections in both inpatient and outpatient are common and widespread use of antibiotics is often the cause of emerging one or more antibiotic-resistant microorganisms [2]. Most studies have shown higher antibiotic resistance in bacterial strains isolated from hospitalized patients than outpatients. In this study, antibiogram was performed using disk diffusion susceptibility method according to NCCLS standards of the International Committee [3]. 8 different antibiotics, including ciprofloxacin (CP: 30 μg, ceftriaxone (CRO: 30 μg, cephalotin (CF: 30 μg, cefixime (CFM: 5 μg, cotrimoxazole (SXT, nalidixic acid (NA: 30 μg, nitrofurantoin (FM: 300 μg, gentamicin (GM: 10 μg were used for antibiogram. During 1388 the total number of urine samples sent to hospital microbiology laboratories valiasr (aj of Arak was 5156, of which 446 samples (65.8% were positive for E. coli culture.

  2. Antimicrobial Susceptibility of Escherichia coli Strains Isolated from Alouatta spp. Feces to Essential Oils

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    Valéria Maria Lara

    2016-01-01

    Full Text Available This study evaluated the in vitro antibacterial activity of essential oils from Lippia graveolens (Mexican oregano, Origanum vulgaris (oregano, Thymus vulgaris (thyme, Rosmarinus officinalis (rosemary, Cymbopogon nardus (citronella, Cymbopogon citratus (lemongrass, and Eucalyptus citriodora (eucalyptus against Escherichia coli (n=22 strains isolated from Alouatta spp. feces. Minimum inhibitory concentration (MIC and minimum bactericidal concentration (MBC were determined for each isolate using the broth microdilution technique. Essential oils of Mexican oregano (MIC mean = 1818 μg mL−1; MBC mean = 2618 μg mL−1, thyme (MIC mean = 2618 μg mL−1; MBC mean = 2909 μg mL−1, and oregano (MIC mean = 3418 μg mL−1; MBC mean = 4800 μg mL−1 showed the best antibacterial activity, while essential oils of eucalyptus, rosemary, citronella, and lemongrass displayed no antibacterial activity at concentrations greater than or equal to 6400 μg mL−1. Our results confirm the antimicrobial potential of some essential oils, which deserve further research.

  3. Caracterização da virulência da cepa de Escherichia coli - BK99 Virulence characterization of strain Escherichia coli - BK99

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    Benito Guimarães de Brito

    2001-06-01

    Full Text Available Com o objetivo de identificar a patogenicidade e resistência a antimicrobianos da cepa de E. coli BK99, foram utilizados alguns testes: aglutinação em lâmina para detecção da fímbria F5, produção de STa, ensaios para hemolisinas e colicinas, patogenicidade em leitões e antibiograma. A cepa BK99 apresentou o seguinte perfil: F1+, F5+, STa+, Col V+, Hly-, ST R, KA R, NO R, TT R SF R e foi capaz de provocar a doença clínica e morte em leitões inoculados; também foi possível o resgate dessa cepa de fezes diarréicas e do conteúdo intestinal dos leitões revelando, assim, alto índice de recuperação de colônias portadoras da fímbria F5+. Os resultados permitem concluir que a cepa de E. coli BK99 é produtora de fatores de virulência e reproduz experimentalmente a colibacilose suína neonatal.In order to evaluate the pathogenicity and antimicrobial resistance pattern of BK99 E. coli strain, several tests were assessed: slide agglutination for detection of the fimbriae F5, STa production, hemolytic and colicin activity, pathogenicity assessement using piglet inoculation and antimicrobial resistance to drugs. The strain BK99 showed the following profile: F1+, F5+, STa+, Col V+, Hly-, ST R, KA R, NO R, TT R SF R. It produced clinical disease and death of infected piglets. Moreover, it was possible to recover the BK99 strain from diarrheic feces and from the gut contents of the piglet, with high rate of recovery of colonies expressing fimbriae F5+. The present results suggest that the E. coli BK99 strain could produce virulence factors and experimentally reproduce neonatal colibacillosis in pigs.

  4. Restoration of growth by manganese in a mutant strain of Escherichia coli lacking most known iron and manganese uptake systems

    DEFF Research Database (Denmark)

    Taudte, Nadine; German, Nadezhda; Zhu, Yong-Guan

    2016-01-01

    The interplay of manganese and iron homeostasis and oxidative stress in Escherichia coli can give important insights into survival of bacteria in the phagosome and under differing iron or manganese bioavailabilities. Here, we characterized a mutant strain devoid of all know iron/manganese......-uptake systems relevant for growth in defined medium. Based on these results an exit strategy enabling the cell to cope with iron depletion and use of manganese as an alternative for iron could be shown. Such a strategy would also explain why E. coli harbors some iron- or manganese-dependent iso......-enzymes such as superoxide dismutases or ribonucleotide reductases. The benefits for gaining a means for survival would be bought with the cost of less efficient metabolism as indicated in our experiments by lower cell densities with manganese than with iron. In addition, this strain was extremely sensitive to the metalloid...

  5. Nisin in Combination with Cinnamaldehyde and EDTA to Control Growth of Escherichia coli Strains of Swine Origin

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    Des Field

    2017-12-01

    Full Text Available Post-weaning diarrhoea (PWD due to enterotoxigenic Escherichia coli (ETEC is an economically important disease in pig production worldwide. Although antibiotics have contributed significantly to mitigate the economic losses caused by PWD, there is major concern over the increased incidence of antimicrobial resistance among bacteria isolated from pigs. Consequently, suitable alternatives that are safe and effective are urgently required. Many naturally occurring compounds, including the antimicrobial peptide nisin and a number of plant essential oils, have been widely studied and are reported to be effective as antimicrobial agents against pathogenic microorganisms. Here, we evaluate the potential of nisin in combination with the essential oil cinnamaldehyde and ethylenediaminetetraacetic acid (EDTA to control the growth of E. coli strains of swine origin including two characterized as ETEC. The results reveal that the use of nisin (10 μM with low concentrations of trans-cinnamaldehyde (125 μg/mL and EDTA (0.25–2% resulted in extended lag phases of growth compared to when either antimicrobial is used alone. Further analysis through kill curves revealed that an approximate 1-log reduction in E. coli cell counts was observed against the majority of targets tested following 3 h incubation. These results highlight the potential benefits of combining the natural antimicrobial nisin with trans-cinnamaldehyde and EDTA as a new approach for the inhibition of E. coli strains of swine origin.

  6. Fatores de virulência em linhagens de Escherichia coli isoladas de mastite bovina Virulence factors in Escherichia coli strains isolated from bovine mastitis

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    M.G. Ribeiro

    2006-10-01

    Full Text Available Avaliou-se a ocorrência de fatores de virulência e do sorotipo O157:H7 em 120 linhagens de Escherichia coli, isoladas de 80 casos de mastite clínica bovina e 40 de mastite subclínica. Verificou-se alfa-hemolisina em oito (6,7% linhagens, isoladas de cinco casos de mastite clínica e três de mastite subclínica e em nenhuma das estirpes detectou-se enteroemolisina. A presença de sideróforos foi encontrada em 11 (9,2% linhagens, sete de mastite clínica e quatro de subclínica. Em duas (1,7% estirpes isoladas de mastite subclínica, identificou-se enterotoxina STa. Observou-se efeito citopático em células vero compatível com a produção de verotoxina-VT em cinco (4,2% linhagens, duas de mastite clínica e três subclínicas. Em uma (0,8% linhagem isolada de mastite clínica, detectou-se efeito citopático compatível com o fator necrosante citotóxico. Nenhuma estirpe apresentou-se sorbitol-negativa no MacConkey-sorbitol, tampouco aglutinou com o sorotipo O157:H7. Os antimicrobianos mais efetivos foram polimixina B (97,5% e norfloxacina (95,8%. Observou-se multi-resistência a dois ou mais antimicrobianos em 24 (20% estirpes, principalmente com o uso de ampicilina e ceftiofur.The occurrence of different virulence factors and O157:H7 serotype investigation in 120 Escherichia coli strains isolated from clinical (80 cases and subclinical (40 cases bovine mastitis was evaluated. Alpha-haemolysin was detected in 8 (6.7% strains (5 clinical and 3 subclinical cases. None strain showed enterohaemolysin production. E. coli growth under iron restriction conditions (siderophores production was observed in 11 (9.2% strains (7 clinical and 4 subclinical cases. STa enterotoxin was detected in 2 (1.7% strains from subclinical cases. Cytotoxic effect in vero cells compatible with verotoxin-VT production was observed in 5 (4.2% strains (2 clinical and 3 subclinical cases. One strain (0.8% isolated from clinical mastitis showed cytophatic effect in vero

  7. Production of 3-Hydroxypropionic Acid via the Propionyl-CoA Pathway Using Recombinant Escherichia coli Strains.

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    Hui Luo

    Full Text Available Our study aimed to produce the commercially promising platform chemical 3-hydroxypropionic acid (3-HP via the propionyl-CoA pathway in genetically engineered Escherichia coli. Recombinant E. coli Ec-P overexpressing propionyl-CoA dehydrogenase (PACD, encoded by the pacd gene from Candida rugosa under the T7 promoter produced 1.33 mM of 3-HP in a shake flask culture supplemented with 0.5% propionate. When propionate CoA-transferase (PCT, encoded by the pct gene from Megasphaera elsdenii and 3-hydroxypropionyl-CoA dehydratase (HPCD, encoded by the hpcd gene from Chloroflexus aurantiacus were expressed along with PACD, the 3-HP titer of the resulting E. coli Ec-PPH strain was improved by 6-fold. The effect of the cultivation conditions on the 3-HP yield from propionate in the Ec-PPH strain was also investigated. When cultured at 30°C with 1% glucose in addition to propionate, 3-HP production by Ec-PPH increased 2-fold and 12-fold compared to the cultivation at 37°C (4.23 mM or without glucose (0.68 mM. Deletion of the ygfH gene encoding propionyl-CoA: succinate CoA-transferase from Ec-PPH (resulting in the strain Ec-△Y-PPH led to increase of 3-HP production in shake flask experiments (15.04 mM, whereas the strain Ec-△Y-PPH with deletion of the prpC gene (encoding methylcitrate synthase in the methylcitrate cycle produced 17.76 mM of 3-HP. The strain Ec-△Y-△P-PPH with both ygfH and prpC genes deleted produced 24.14 mM of 3-HP, thus showing an 18-fold increase in the 3-HP titer in compare to the strain Ec-P.

  8. Chromosomal insertion of the entire Escherichia coli lactose operon, into two strains of Pseudomonas, using a modified mini-Tn5 delivery system

    DEFF Research Database (Denmark)

    Hansen, L. H.; Sørensen, S. J.; Jensen, Lars Bogø

    1997-01-01

    A 12-kb PstI fragment including the entire E. coli lactose operon (lacIPOZYA) was inserted in one copy into the chromosome of Pseudomonas putida, Pseudomonas fluorescens and an E. coli strain with lac(-) phenotype. This was made possible by improvements of an already existing mini-Tn5 transposon...... flanked by NotI sites needed in the mini-Tn5 delivery system; (b) the generation of E. coli nonlysogenic strains expressing the pi protein thus being capable of maintaining and delivering R6K-based mini-Tn5 vectors to other E. coli strains; (c) the successful insertion of the E. coli lactose operon...... into the P. fluorescens chromosome giving P. fluorescens the ability to grow on lactose; (d) evidence from Southern blotting that contradicts the assumption that the mini-Tn5 delivery system always creates one-copy inserts. These improvements allow insertion of large DNA fragments encoding highly expressed...

  9. Cefoxitin resistance mediated by loss of a porin in clinical strains of Klebsiella pneumoniae and Escherichia coli

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    Ananthan S

    2005-01-01

    Full Text Available PURPOSE: Porins are outer membrane protein (OMP that form water filled channels that permit the diffusion of small hydrophilic solutes like -lactam antibiotics across the outer membrane. Two major porins that facilitate diffusion of antimicrobials have been described in Klebsiella spp. and Escherichia coli. The present study was carried out to examine the role of porins among Extended Spectrum -Lactamase (ESBL and AmpC -Lactamase positive strains of Klebsiella spp. and E.coli. METHODS: Preparation of OMP from phenotypically characterized clinical isolates K.pneumoniae and E.coli and the separation of the proteins by sodium dodecyl sulfate - polyacrylamide gel electrophoresis were performed as per a previously described procedure. RESULTS: OMP analysis revealed that cefoxitin and ceftazidime resistance was mediated by loss of a porin Omp K35 in the isolates of K.pneumoniae and E.coli. CONCLUSIONS: Loss of porin mediated resistance mechanism against cefoxitin was observed among the multidrug resistant K.pneumoniae and E.coli.

  10. Survey on the occurrence of shiga toxin producing strains of Escherichia coli (STEC) in drinking water from central Hessia

    Energy Technology Data Exchange (ETDEWEB)

    Stelz, A.; Zschoeck, M. [Untersuchungsamt Hessen, Giessen (Germany); Fels, K.; Alter, E. [Fachhochschule Giessen-Friedberg, Giessen (Germany)

    2001-07-01

    Consumption of unheated bovine food is said to be the main cause of outbreaks of enterohemorrhagic colitis (EC) and hemolytic syndrome (HUS) by E. coli O157 in man. Some cases were attributed to the ingestion of contaminated drinking water. Certain types of resources for drinking water supply are at risk of contamination with cattle faeces or sewage. In routine drinking water control E. coli is an index organism and must not be found in a sample of 100 ml. We investigated a total of 1700 drinking water samples from central Hessia (Germany) for shiga toxin producing strains of E. coli (STEC). A developed sensitive investigation scheme made it possible to detect up to 10 STEC per 100 ml water sample at least. ELISA was used for detection of shiga toxins 1 and 2, m-PCR for the genes encoding stx1, stx2, EHEC-hlyA and eaeA, plating on Enterohemolysin agar for detection of the enterohemolysin phenotype and slide agglutination technique for confirming E. coli O157. In 108 out of 1700 drinking water samples E. coli was detected, but none of the isolates belonged to serotype O157. ST1 and ST2 were not produced by the isolates. Thus, under normal circumstances drinking water in central Hessia seems to be no vehicle for STEC. (orig.)

  11. Improvement in ethanol productivity of engineered E. coli strain SSY13 in defined medium via adaptive evolution.

    Science.gov (United States)

    Jilani, Syed Bilal; Venigalla, Siva Sai Krishna; Mattam, Anu Jose; Dev, Chandra; Yazdani, Syed Shams

    2017-09-01

    E. coli has the ability to ferment both C5 and C6 sugars and produce mixture of acids along with small amount of ethanol. In our previous study, we reported the construction of an ethanologenic E. coli strain by modulating flux through the endogenous pathways. In the current study, we made further changes in the strain to make the overall process industry friendly; the changes being (1) removal of plasmid, (2) use of low-cost defined medium, and (3) improvement in consumption rate of both C5 and C6 sugars. We first constructed a plasmid-free strain SSY13 and passaged it on AM1-xylose minimal medium plate for 150 days. Further passaging was done for 56 days in liquid AM1 medium containing either glucose or xylose on alternate days. We observed an increase in specific growth rate and carbon utilization rate with increase in passage numbers until 42 days for both glucose and xylose. The 42nd day passaged strain SSK42 fermented 113 g/L xylose in AM1 minimal medium and produced 51.1 g/L ethanol in 72 h at 89% of maximum theoretical yield with ethanol productivity of 1.4 g/L/h during 24-48 h of fermentation. The ethanol titer, yield and productivity were 49, 40 and 36% higher, respectively, for SSK42 as compared to unevolved SSY13 strain.

  12. Complete Genome Sequence of ER2796, a DNA Methyltransferase-Deficient Strain of Escherichia coli K-12.

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    Brian P Anton

    Full Text Available We report the complete sequence of ER2796, a laboratory strain of Escherichia coli K-12 that is completely defective in DNA methylation. Because of its lack of any native methylation, it is extremely useful as a host into which heterologous DNA methyltransferase genes can be cloned and the recognition sequences of their products deduced by Pacific Biosciences Single-Molecule Real Time (SMRT sequencing. The genome was itself sequenced from a long-insert library using the SMRT platform, resulting in a single closed contig devoid of methylated bases. Comparison with K-12 MG1655, the first E. coli K-12 strain to be sequenced, shows an essentially co-linear relationship with no major rearrangements despite many generations of laboratory manipulation. The comparison revealed a total of 41 insertions and deletions, and 228 single base pair substitutions. In addition, the long-read approach facilitated the surprising discovery of four gene conversion events, three involving rRNA operons and one between two cryptic prophages. Such events thus contribute both to genomic homogenization and to bacteriophage diversification. As one of relatively few laboratory strains of E. coli to be sequenced, the genome also reveals the sequence changes underlying a number of classical mutant alleles including those affecting the various native DNA methylation systems.

  13. Antimicrobial susceptibility testing of Escherichia coli strains isolated from urinary tract infections to fluoroquinolones and detection of gyrA mutations in resistant strains

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    Akbari-Nakhjavani F.

    2007-05-01

    Full Text Available Widespread uses of fluoroquinolones have resulted in increasing incidences of resistance against these agents all over the world. The aim of this study was to assess, susceptibility of Escherichia coli strains from patients with Urinary Tract Infection against common fluoroquinolones and detection of mutations in the gyrA gene. Antimicrobial susceptibility testing of 164 E.coli isolates from patients with UTI, was evaluated by disk agar diffusion (DAD and MIC methods. Polymerase chain reaction of E.coli strains were performed by amplification of Quinolone Resistance Determining Region (QRDR of gyrA gene. PCR products were tested by Conformational Sensitive Gel Electrophoresis (CSGE and those with hetrodublexes were selected and examined by DNA sequencing. According to disc agar diffusion, 49.3% were resistant to nalidixic acid, 41.4% to norfloxacin, 44.5% to ofloxacin and 40.2 % to ciprofloxacin. By Minimal Inhibitory Concentration (MIC testing a high-level of resistance (42.1% to ciprofloxacin was observed. Mutations in codons 83 and 87 in all 81 isolates were positive by CSGE method.

  14. FREQUENCY AND DISTRIBUTION OF DIARRHOEAGENIC ESCHERICHIA COLI STRAINS ISOLATED FROM PEDIATRIC PATIENTS WITH DIARRHOEA IN BOSNIA AND HERZEGOVINA

    OpenAIRE

    Dedeić-Ljubović, AmeLa; Hukić, Mirsada; Bekić, DaRia; Zvizdić, AmrA

    2009-01-01

    Diarrhoeal disease is a major cause of illness and death among infants and young children worldwide. Among the Escherichia coli (E. coli) causing intestinal diseases, there are six well-described categories: enteroaggregative E. coli (EAEC), diffusely adherent E. coli (DAEC), enteroinvasive E. coli (EIEC), entero-pathogenic E. coli (EPEC), enterohaemorrhagic E. coli (EHEC) and enterotoxigenic E. coli (ETEC).

  15. Genomic and Transcriptomic Analysis of Escherichia coli Strains Associated with Persistent and Transient Bovine Mastitis and the Role of Colanic Acid.

    Science.gov (United States)

    Lippolis, John D; Holman, Devin B; Brunelle, Brian W; Thacker, Tyler C; Bearson, Bradley L; Reinhardt, Timothy A; Sacco, Randy E; Casey, Thomas A

    2018-01-01

    Escherichia coli is a leading cause of bacterial mastitis in dairy cattle. It is most often transient in nature, causing an infection that lasts 2 to 3 days. However, E. coli has been shown to cause a persistent infection in a minority of cases. Mechanisms that allow for a persistent E. coli infection are not fully understood. The goal of this work was to determine differences between E. coli strains originally isolated from dairy cattle with transient and persistent mastitis. Using RNA sequencing, we show gene expression differences in nearly 200 genes when bacteria from the two clinical phenotypes are compared. We sequenced the genomes of the E. coli strains and report genes unique to the two phenotypes. Differences in the wca operon, which encodes colanic acid, were identified by DNA as well as RNA sequencing and differentiated the two phenotypes. Previous work demonstrated that E. coli strains that cause persistent infections were more motile than those that cause transient infections. Deletion of genes in the wca operon from a persistent-infection strain resulted in a reduction of motility as measured in swimming and swarming assays. Furthermore, colanic acid has been shown to protect bacteria from complement-mediated killing. We show that transient-infection E. coli strains were more sensitive to complement-mediated killing. The deletion of genes from the wca operon caused a persistent-infection E. coli strain to become sensitive to complement-mediated killing. This work identifies important differences between E. coli strains that cause persistent and transient mammary infections in dairy cattle. This is a work of the U.S. Government and is not subject to copyright protection in the United States. Foreign copyrights may apply.

  16. Complete Draft Genome Sequence of Escherichia coli KRX, a Strain for Efficient Cloning and High-Yield Expression of Proteins under Control of the T7 RNA Polymerase

    OpenAIRE

    Schwarzhans, Jan-Philipp; Wibberg, Daniel; Winkler, Anika; Kalinowski, Jörn; Friehs, Karl

    2017-01-01

    ABSTRACT Escherichia coli KRX is a strain offering both a high transformation efficiency and the possibility to produce the target protein to high yields in one host, avoiding additional cloning steps. Here, the draft genome sequence of E. coli KRX is presented and provides the genetic basis for additional biotechnological applications.

  17. Towards a Molecular Definition of Enterohemorrhagic Escherichia coli (EHEC): Detection of Genes Located on O Island 57 as Markers To Distinguish EHEC from Closely Related Enteropathogenic E. coli Strains

    Science.gov (United States)

    Delannoy, Sabine; Beutin, Lothar

    2013-01-01

    Among strains of Shiga-toxin (Stx) producing Escherichia coli (STEC), seven serogroups (O26, O45, O103, O111, O121, O145, and O157) are associated with severe clinical illness in humans. These strains are also called enterohemorrhagic E. coli (EHEC), and the development of methods for their reliable detection from food has been challenging thus far. PCR detection of major EHEC virulence genes stx1, stx2, eae, and O-serogroup-specific genes is useful but does not identify EHEC strains specifically. Searching for the presence of additional genes issued from E. coli O157:H7 genomic islands OI-122 and OI-71 increases the specificity but does not clearly discriminate EHEC from enteropathogenic E. coli (EPEC) strains. Here, we identified two putative genes, called Z2098 and Z2099, from the genomic island OI-57 that were closely associated with EHEC and their stx-negative derivative strains (87% for Z2098 and 91% for Z2099). Z2098 and Z2099 were rarely found in EPEC (10% for Z2098 and 12% for Z2099), STEC (2 and 15%), and apathogenic E. coli (1% each) strains. Our findings indicate that Z2098 and Z2099 are useful genetic markers for a more targeted diagnosis of typical EHEC and new emerging EHEC strains. PMID:23325824

  18. Towards a molecular definition of enterohemorrhagic Escherichia coli (EHEC): detection of genes located on O island 57 as markers to distinguish EHEC from closely related enteropathogenic E. coli strains.

    Science.gov (United States)

    Delannoy, Sabine; Beutin, Lothar; Fach, Patrick

    2013-04-01

    Among strains of Shiga-toxin (Stx) producing Escherichia coli (STEC), seven serogroups (O26, O45, O103, O111, O121, O145, and O157) are associated with severe clinical illness in humans. These strains are also called enterohemorrhagic E. coli (EHEC), and the development of methods for their reliable detection from food has been challenging thus far. PCR detection of major EHEC virulence genes stx1, stx2, eae, and O-serogroup-specific genes is useful but does not identify EHEC strains specifically. Searching for the presence of additional genes issued from E. coli O157:H7 genomic islands OI-122 and OI-71 increases the specificity but does not clearly discriminate EHEC from enteropathogenic E. coli (EPEC) strains. Here, we identified two putative genes, called Z2098 and Z2099, from the genomic island OI-57 that were closely associated with EHEC and their stx-negative derivative strains (87% for Z2098 and 91% for Z2099). Z2098 and Z2099 were rarely found in EPEC (10% for Z2098 and 12% for Z2099), STEC (2 and 15%), and apathogenic E. coli (1% each) strains. Our findings indicate that Z2098 and Z2099 are useful genetic markers for a more targeted diagnosis of typical EHEC and new emerging EHEC strains.

  19. Biofilm-Exclusion of Uropathogenic Bacteria by Selected Asymptomatic Bacteriuria Escherichia Coli Strains

    DEFF Research Database (Denmark)

    Ferriéres, L.; Hancock, Viktoria; Klemm, Per

    2007-01-01

    was investigated. It was found that there is a strong bias for biofilm formation by the ABU strains. Not only were the ABU strains significantly better biofilm formers than UPEC strains, they were also able to out-compete UPEC strains as well as uropathogenic strains of Klebsiella spp. during biofilm formation...

  20. Survival, Biofilm Formation, and Growth Potential of Environmental and Enteric Escherichia coli Strains in Drinking Water Microcosms.

    Science.gov (United States)

    Abberton, Cathy L; Bereschenko, Ludmila; van der Wielen, Paul W J J; Smith, Cindy J

    2016-09-01

    Escherichia coli is the most commonly used indicator for fecal contamination in drinking water distribution systems (WDS). The assumption is that E. coli bacteria are of enteric origin and cannot persist for long outside their host and therefore act as indicators of recent contamination events. This study investigates the fate of E. coli in drinking water, specifically addressing survival, biofilm formation under shear stress, and regrowth in a series of laboratory-controlled experiments. We show the extended persistence of three E. coli strains (two enteric isolates and one soil isolate) in sterile and nonsterile drinking water microcosms at 8 and 17°C, with T90 (time taken for a reduction in cell number of 1 log10 unit) values ranging from 17.4 ± 1.8 to 149 ± 67.7 days, using standard plate counts and a series of (reverse transcription-)quantitative PCR [(RT-)Q-PCR] assays targeting 16S rRNA, tuf, uidA, and rodA genes and transcripts. Furthermore, each strain was capable of attaching to a surface and replicating to form biofilm in the presence of nutrients under a range of shear stress values (0.6, 2.0, and 4.4 dynes [dyn] cm(-2); BioFlux system; Fluxion); however, cell numbers did not increase when drinking water flowed over the biofilm (P > 0.05 by t test). Finally, E. coli regrowth within drinking water microcosms containing polyethylene PE-100 pipe wall material was not observed in the biofilm or water phase using a combination of culturing and Q-PCR methods for E. coli The results of this work highlight that when E. coli enters drinking water it has the potential to survive and attach to surfaces but that regrowth within drinking water or biofilm is unlikely. The provision of clean, safe drinking water is fundamental to society. WDS deliver water to consumers via a vast network of pipes. E. coli is used as an indicator organism for recent contamination events based on the premise that it cannot survive for long outside its host. A key public health

  1. Rare codon content affects the solubility of recombinant proteins in a codon bias-adjusted Escherichia coli strain

    Directory of Open Access Journals (Sweden)

    Ceccarelli Eduardo A

    2009-07-01

    Full Text Available Abstract Background The expression of heterologous proteins in Escherichia coli is strongly affected by codon bias. This phenomenon occurs when the codon usage of the mRNA coding for the foreign protein differs from that of the bacterium. The ribosome pauses upon encountering a rare codon and may detach from the mRNA, thereby the yield of protein expression is reduced. Several bacterial strains have been engineered to overcome this effect. However, the increased rate of translation may lead to protein misfolding and insolubilization. In order to prove this assumption, the solubility of several recombinant proteins from plants was studied in a codon bias-adjusted E. coli strain. Results The expression of eight plant proteins in Escherichia coli BL21(DE3-pLysS and BL21(DE3-CodonPlus-pRIL was systematically studied. The CodonPlus strain contains extra copies of the argU, ileY, and leuW tRNA genes, which encode tRNAs that recognize the codons AGA/AGG, AUA and CUA, respectively (RIL codons. The level of expression and solubility of the recombinant proteins were analyzed by means of sodium dodecyl sulfate polyacrylamide gel electrophoresis and Western blotting. We found that for all proteins the solubility was at least 25% in the BL21(DE3-pLysS strain. However, when expressed in the BL21(DE3-CodonPlus-pRIL strain, proteins having more than 5% of amino acids coded by RIL codons were localized mainly in the insoluble fraction. Also, their expression caused retarded growth and low cell yield in the codon bias-adjusted strain at all temperatures tested. On the contrary, the solubility of proteins containing less than 5% of amino acids coded by RIL codons remained unchanged in both strains and their expression caused no effect on cell growth. Conclusion Our results show that the expression of heterologous proteins coded by high RIL codon content coding sequences in a codon bias-adjusted strain is detrimental for their solubility. Our data support the

  2. Molecular Analysis of Asymptomatic Bacteriuria Escherichia coli Strain VR50 Reveals Adaptation to the Urinary Tract by Gene Acquisition

    Science.gov (United States)

    Ben Zakour, Nouri L.; Totsika, Makrina; Forde, Brian M.; Watts, Rebecca E.; Mabbett, Amanda N.; Szubert, Jan M.; Sarkar, Sohinee; Phan, Minh-Duy; Peters, Kate M.; Petty, Nicola K.; Alikhan, Nabil-Fareed; Sullivan, Mitchell J.; Gawthorne, Jayde A.; Stanton-Cook, Mitchell; Nhu, Nguyen Thi Khanh; Chong, Teik Min; Yin, Wai-Fong; Chan, Kok-Gan; Hancock, Viktoria; Ussery, David W.; Ulett, Glen C.

    2015-01-01

    Urinary tract infections (UTIs) are among the most common infectious diseases of humans, with Escherichia coli responsible for >80% of all cases. One extreme of UTI is asymptomatic bacteriuria (ABU), which occurs as an asymptomatic carrier state that resembles commensalism. To understand the evolution and molecular mechanisms that underpin ABU, the genome of the ABU E. coli strain VR50 was sequenced. Analysis of the complete genome indicated that it most resembles E. coli K-12, with the addition of a 94-kb genomic island (GI-VR50-pheV), eight prophages, and multiple plasmids. GI-VR50-pheV has a mosaic structure and contains genes encoding a number of UTI-associated virulence factors, namely, Afa (afimbrial adhesin), two autotransporter proteins (Ag43 and Sat), and aerobactin. We demonstrated that the presence of this island in VR50 confers its ability to colonize the murine bladder, as a VR50 mutant with GI-VR50-pheV deleted was attenuated in a mouse model of UTI in vivo. We established that Afa is the island-encoded factor responsible for this phenotype using two independent deletion (Afa operon and AfaE adhesin) mutants. E. coli VR50afa and VR50afaE displayed significantly decreased ability to adhere to human bladder epithelial cells. In the mouse model of UTI, VR50afa and VR50afaE displayed reduced bladder colonization compared to wild-type VR50, similar to the colonization level of the GI-VR50-pheV mutant. Our study suggests that E. coli VR50 is a commensal-like strain that has acquired fitness factors that facilitate colonization of the human bladder. PMID:25667270

  3. Gene sequencing, cloning, and expression of the recombinant L- Asparaginase of Pseudomonas aeruginosa SN4 strain in Escherichia coli

    Directory of Open Access Journals (Sweden)

    Arastoo Badoei-dalfard

    2016-03-01

    Full Text Available Introduction: L- asparaginase is in an excessive demand in medical applications and in food treating industries, the request for this therapeutic enzyme is growing several folds every year. Materials and methods: In this study, a L- asparaginase gene from Pseudomonas aeruginosa strain SN4 was sequenced and cloned in E. coli. Primers were designed based on L- asparaginase from P. aeruginosa DSM 50071, which show high similarity to SN4 strain, according to 16S rRNA sequence. The L- asparaginase gene was exposed to restriction digestion with NdeI and XhoI enzymes and then ligated into pET21a plasmid. The ligated sample was transformed into competent E. coli (DE3 pLysS DH5a cells, according to CaCl2 method. The transformed E. coli cells were grown into LB agar plate containing 100 µg/ml ampicillin, IPTG (1 mM. Results: Recombinant L- asparaginase from E. coli BL21 induced after 9 h of incubation and showed high L- asparaginase activity about 93.4 IU/ml. Recombinant L- asparaginase sequencing and alignments showed that the presumed amino acid sequence composed of 350 amino acid residues showed high similarity with P. aeruginosa L- asparaginases about 99%. The results also indicated that SN4 L- asparaginase has the catalytic residues and conserve region similar to other L- asparaginases. Discussion and conclusion: This is the first report on cloning and expression of P. aeruginosa L- asparaginases in Escherichia coli. These results indicated a potent source of L- asparaginase for in vitro and in vivio anticancer consideration. 

  4. Enumeration of sublethally injured Escherichia coli O157:H7 ATCC 43895 and Escherichia coli strain B-41560 using selective agar overlays versus commercial methods.

    Science.gov (United States)

    Smith, Amanda R; Ellison, Alysha L; Robinson, Amanda L; Drake, Maryanne; McDowell, Susan A; Mitchell, James K; Gerard, Patrick D; Heckler, Rachel A; McKillip, John L

    2013-04-01

    Quality control procedures during food processing may involve direct inoculation of food samples onto appropriate selective media for subsequent enumeration. However, sublethally injured bacteria often fail to grow, enabling them to evade detection and intervention measures and ultimately threaten the health of consumers. This study compares traditional selective and nonselective agar-based overlays versus two commercial systems (Petrifilm and Easygel) for recovery of injured E. coli B-41560 and O157:H7 strains. Bacteria were propagated in tryptic soy broth (TSB), ground beef slurry, and infant milk formula to a density of 10(6) to 10(8) CFU/ml and then were stressed for 6 min either in lactic acid (pH 4.5) or heat shocked for 3 min at 60°C. Samples were pour plated in basal layers of either tryptic soy agar (TSA), sorbitol MacConkey agar (SMAC), or violet red bile agar (VRB) and were resuscitated for 4 h prior to addition of agar overlays. Other stressed bacteria were plated directly onto Petrifilm and Easygel. Results indicate that selective and nonselective agar overlays recovered significantly higher numbers (greater than 1 log) of acid- and heat-injured E. coli O157:H7 from TSB, ground beef, and infant milk formula compared with direct plating onto selective media, Petrifilm, or Easygel, while no significant differences among these media combinations were observed for stressed E. coli B-41560. Nonstressed bacteria from TSB and ground beef were also recovered at densities significantly higher in nonselective TSA-TSA and in VRB-VRB and SMAC-SMAC compared with Petrifilm and Easygel. These data underscore the need to implement food safety measures that address sublethally injured pathogens such as E. coli O157:H7 in order to avoid underestimation of true densities for target pathogens.

  5. Metabolic engineering of isopropyl alcohol-producing Escherichia coli strains with13C-metabolic flux analysis.

    Science.gov (United States)

    Okahashi, Nobuyuki; Matsuda, Fumio; Yoshikawa, Katsunori; Shirai, Tomokazu; Matsumoto, Yoshiko; Wada, Mitsufumi; Shimizu, Hiroshi

    2017-12-01

    Metabolic engineering of isopropyl alcohol (IPA)-producing Escherichia coli strains was conducted along with 13 C-metabolic flux analysis (MFA). A metabolically engineered E. coli strain expressing the adc gene derived from Clostridium acetobutylicum and the IPADH gene from C. beijerinckii did not produce IPA during its exponential growth phase in the aerobic batch culture. 13 C-MFA was carried out, and revealed a deficiency in NADPH regeneration for IPA production in growth phase. Based on these findings, we used nitrogen-starved culture conditions to reduce NADPH consumption for biomass synthesis. As a result, IPA yield was increased to 20% mol/mol glucose. 13 C-MFA revealed that the relative flux levels through the oxidative pentose phosphate (PP) pathway and the TCA cycle were elevated in nitrogen-starved condition relative to glucose uptake rate. To prevent CO 2 release in the 6-phosphogluconate dehydrogenase (6PGDH) reaction, metabolism of this E. coli strain was further engineered to redirect glycolytic flux to the glucose 6-phosphate dehydrogenase (G6PDH) and Entner-Doudoroff (ED) pathway. IPA yield of 55% mol/mol glucose was achieved by combining the nitrogen-starved culture condition with the metabolic redirection. The 13 C-MFA data and intracellular NADPH levels obtained under these IPA production conditions revealed linear correlations between the specific IPA production rate and NADPH concentration, as well as between IPA yield and the pyruvate dehydrogenase (PDH) flux. Our results showed that 13 C-MFA is a helpful tool for metabolic engineering studies, and that further improvement in IPA production by E. coli may be achieved by fine-tuning the cofactor ratio and concentrations, as well as optimizing the metabolic pathways and culture conditions. © 2017 Wiley Periodicals, Inc.

  6. Atypical Enteropathogenic Escherichia coli Strains form Biofilm on Abiotic Surfaces Regardless of Their Adherence Pattern on Cultured Epithelial Cells

    Directory of Open Access Journals (Sweden)

    Hebert F. Culler

    2014-01-01

    Full Text Available The aim of this study was to determine the capacity of biofilm formation of atypical enteropathogenic Escherichia coli (aEPEC strains on abiotic and biotic surfaces. Ninety-one aEPEC strains, isolated from feces of children with diarrhea, were analyzed by the crystal violet (CV assay on an abiotic surface after 24 h of incubation. aEPEC strains representing each HEp-2 cell type of adherence were analyzed after 24 h and 6, 12, and 18 days of incubation at 37°C on abiotic and cell surfaces by CFU/cm2 counting and confocal laser scanning microscopy (CLSM. Biofilm formation on abiotic surfaces occurred in 55 (60.4% of the aEPEC strains. There was no significant difference in biofilm biomass formation on an abiotic versus prefixed cell surface. The biofilms could be visualized by CLSM at various developmental stages. aEPEC strains are able to form biofilm on an abiotic surface with no association with their adherence pattern on HEp-2 cells with the exception of the strains expressing UND (undetermined adherence. This study revealed the capacity of adhesion and biofilm formation by aEPEC strains on abiotic and biotic surfaces, possibly playing a role in pathogenesis, mainly in cases of persistent diarrhea.

  7. Atypical Enteropathogenic Escherichia coli Strains form Biofilm on Abiotic Surfaces Regardless of Their Adherence Pattern on Cultured Epithelial Cells

    Science.gov (United States)

    Culler, Hebert F.; Mota, Cristiane M.; Abe, Cecilia M.; Elias, Waldir P.; Sircili, Marcelo P.; Franzolin, Marcia R.

    2014-01-01

    The aim of this study was to determine the capacity of biofilm formation of atypical enteropathogenic Escherichia coli (aEPEC) strains on abiotic and biotic surfaces. Ninety-one aEPEC strains, isolated from feces of children with diarrhea, were analyzed by the crystal violet (CV) assay on an abiotic surface after 24 h of incubation. aEPEC strains representing each HEp-2 cell type of adherence were analyzed after 24 h and 6, 12, and 18 days of incubation at 37°C on abiotic and cell surfaces by CFU/cm2 counting and confocal laser scanning microscopy (CLSM). Biofilm formation on abiotic surfaces occurred in 55 (60.4%) of the aEPEC strains. There was no significant difference in biofilm biomass formation on an abiotic versus prefixed cell surface. The biofilms could be visualized by CLSM at various developmental stages. aEPEC strains are able to form biofilm on an abiotic surface with no association with their adherence pattern on HEp-2 cells with the exception of the strains expressing UND (undetermined adherence). This study revealed the capacity of adhesion and biofilm formation by aEPEC strains on abiotic and biotic surfaces, possibly playing a role in pathogenesis, mainly in cases of persistent diarrhea. PMID:24883330

  8. Chromosomal transformation of Escherichia coli recD strains with linearized plasmids.

    OpenAIRE

    Russell, C B; Thaler, D S; Dahlquist, F W

    1989-01-01

    Wild-type Escherichia coli are resistant to genetic transformation by purified linear DNA, probably in part because of exonuclease activity. We demonstrate that E. coli containing a recD mutation could be easily transformed by linearized plasmids containing a selectable marker. The marker was transferred to the chromosome by homologous recombination, whereas plasmid markers not in the region of homology were lost.

  9. Proteomic analysis reveals protein expression differences in Escherichia coli strains associated with persistent versus transient mastitis

    Science.gov (United States)

    Escherichia coli is a leading cause of bacterial mastitis in dairy cattle. Typically this infection is transient in nature, causing an infection that lasts 2-3 days. However, in a minority of cases, E. coli has been shown to cause a persistent intramammary infection. The mechanisms that allow for...

  10. Investigation on prevalence of Escherichia coli strains carrying virulence genes ipaH, estA, eaeA and bfpA isolated from different water sources

    Directory of Open Access Journals (Sweden)

    Reza Ranjbar

    2016-04-01

    Full Text Available Objective: To investigate prevalence of Escherichia coli (E. coli strains carrying virulence genes ipaH, estA, eaeA and bfpA, isolated from different water sources in Alborz Province. Methods: This study was carried out in 2014. The research included all E. coli strains isolated from different surface water sources in Alborz Province of Iran. E. coli isolates were detected and identified by standard microbiological and biochemical tests. The strains were evaluated for the presence of virulence genes ipaH, estA, eaeA and bfpA by PCR using specific primers. The PCR amplicons were visualized via electrophoresis and stained with ethidium bromide. Results: One hundred E. coli strains were isolated and included in the study. The PCR results showed that 97% of the strains harbored ipaH gene. Moreover, estA, eaeA and bfpA genes were found in 37%, 31% and 3% of the isolates. Conclusions: Our finding showed that the prevalence rates of virulence genes ipaH and estA were very high among E. coli strains isolated from different surface water sources in Alborz Province. Considering their plasmid-borne nature, the risk of transmission of these genes between other bacterial species could pose a high threat to public health.

  11. Analysis of the efficiency of recombinant Escherichia coli strain cultivation in a gas-vortex bioreactor.

    Science.gov (United States)

    Savelyeva, Anna V; Nemudraya, Anna A; Podgornyi, Vladimir F; Laburkina, Nadezhda V; Ramazanov, Yuriy A; Repkov, Andrey P; Kuligina, Elena V; Richter, Vladimir A

    2017-09-01

    The levels of aeration and mass transfer are critical parameters required for an efficient aerobic bioprocess, and directly depend on the design features of exploited bioreactors. A novel apparatus, using gas vortex for aeration and mass transfer processes, was constructed in the Center of Vortex Technologies (Novosibirsk, Russia). In this paper, we compared the efficiency of recombinant Escherichia coli strain cultivation using novel gas-vortex technology with conventional bioprocess technologies such as shake flasks and bioreactors with mechanical stirrers. We demonstrated that the system of aeration and agitation used in gas-vortex bioreactors provides 3.6 times higher volumetric oxygen transfer coefficient in comparison with mechanical bioreactor. The use of gas-vortex bioreactor for recombinant E. coli strain cultivation allows to increase the efficiency of target protein expression at 2.2 times for BL21(DE3)/pFK2 strain and at 3.5 times for auxotrophic C600/pRT strain (in comparison with stirred bioreactor). © 2016 International Union of Biochemistry and Molecular Biology, Inc.

  12. Escherichia coli "TatExpress" strains super-secrete human growth hormone into the bacterial periplasm by the Tat pathway.

    Science.gov (United States)

    Browning, Douglas F; Richards, Kirsty L; Peswani, Amber R; Roobol, Jo; Busby, Stephen J W; Robinson, Colin

    2017-12-01

    Numerous high-value proteins are secreted into the Escherichia coli periplasm by the General Secretory (Sec) pathway, but Sec-based production chassis cannot handle many potential target proteins. The Tat pathway offers a promising alternative because it transports fully folded proteins; however, yields have been too low for commercial use. To facilitate Tat export, we have engineered the TatExpress series of super-secreting strains by introducing the strong inducible bacterial promoter, ptac, upstream of the chromosomal tatABCD operon, to drive its expression in E. coli strains commonly used by industry (e.g., W3110 and BL21). This modification significantly improves the Tat-dependent secretion of human growth hormone (hGH) into the bacterial periplasm, to the extent that secreted hGH is the dominant periplasmic protein after only 1 hr induction. TatExpress strains accumulate in excess of 30 mg L-1 periplasmic recombinant hGH, even in shake flask cultures. A second target protein, an scFv, is also shown to be exported at much higher rates in TatExpress strains. © 2017 The Authors. Biotechnology and Bioengineering Published by Wiley Periodicals, Inc.

  13. Survival to different acid challenges and outer membrane protein profiles of pathogenic Escherichia coli strains isolated from pozol, a Mexican typical maize fermented food.

    Science.gov (United States)

    Sainz, Teresita; Pérez, Julia; Villaseca, Jorge; Hernández, Ulises; Eslava, Carlos; Mendoza, Guillermo; Wacher, Carmen

    2005-12-15

    In this study, the acid resistance and the changes in outer membrane protein (Omps) profiles of Escherichia coli strains isolated from pozol, an acid-fermented maize beverage consumed in Southeastern Mexico, were determined. Results showed that adaptation to acid by these E. coli strains significantly enhances their survival in acid conditions. Changes in Omp profiles were found in non-adapted acid challenged cells compared with non-challenged cells that had not been adapted to acid. Challenged adapted cells showed no significant changes in these profiles when compared with the acid adapted non-challenged strains. N-terminal sequences of some of the Omps were determined. The intensity of the main porins OmpC and OmpA was lower in the acid challenged strains, than in the non-challenged ones. The OmpF porin was identified in non-challenged K12 strain, but did not appear in adapted or non-adapted pozol strains nor in E. coli O157:H7. A protein band with an approximate molecular mass of 22 kDa corresponds to OmpW and its expression decreased in pozol strains challenged with HCl and lactic acid. OmpX was one of the main proteins expressed when strains were acid challenged with organic acids. Seventy out of seventy-three E. coli strains isolated from pozol in a previous work [Sainz, T., Wacher, C., Espinoza, J., Centurion, D., Navarro, A., Molina, J., Cravioto, A., Eslava, C., 2001. Survival and characterization of Escherichia coli strains in a typical Mexican acid-fermented food. International Journal of Food Microbiology 71, 169-176] carry this gene and belong to a reported pathogenic class of E. coli strains, or have virulence factors or survived at pH values less than 4.8. We suggest this protein could be involved in survival to stress conditions.

  14. Monitoring and characterization of extended-spectrum beta-lactamases in Escherichia coli strains from healthy and sick animals in Spain in 2003.

    Science.gov (United States)

    Briñas, Laura; Moreno, Miguel Angel; Teshager, Tirushet; Sáenz, Yolanda; Porrero, María Concepción; Domínguez, Lucas; Torres, Carmen

    2005-03-01

    Genes encoding CTX-M-14, CTX-M-9, CTX-M-1, CTX-M-32, SHV-12, TEM-52, or CMY-2 beta-lactamases were detected in 21 Escherichia coli strains recovered during 2003 from sick animals (11 of 459 [2.4%] strains) and healthy animals (10 of 158 [6.3%] strains) in Spain. Twelve of these strains harbored bla(CTX-M) genes and showed unrelated pulsed-field gel electrophoresis patterns.

  15. Monitoring and Characterization of Extended-Spectrum β-Lactamases in Escherichia coli Strains from Healthy and Sick Animals in Spain in 2003

    Science.gov (United States)

    Briñas, Laura; Moreno, Miguel Angel; Teshager, Tirushet; Sáenz, Yolanda; Porrero, María Concepción; Domínguez, Lucas; Torres, Carmen

    2005-01-01

    Genes encoding CTX-M-14, CTX-M-9, CTX-M-1, CTX-M-32, SHV-12, TEM-52, or CMY-2 β-lactamases were detected in 21 Escherichia coli strains recovered during 2003 from sick animals (11 of 459 [2.4%] strains) and healthy animals (10 of 158 [6.3%] strains) in Spain. Twelve of these strains harbored blaCTX-M genes and showed unrelated pulsed-field gel electrophoresis patterns. PMID:15728945

  16. Characterization of Extended-Spectrum β-Lactamase-Producing Escherichia coli Strains Isolated from Retail Foods in Shaanxi Province, China.

    Science.gov (United States)

    Xi, Meili; Wu, Qian; Wang, Xin; Yang, Baowei; Xia, Xiaodong; Li, Dongyu

    2015-05-01

    Extended-spectrum β-lactamase (ESBL)-producing Escherichia coli strains have been reported worldwide; however, the incidence and characterization of foodborne ESBL-producing E. coli strains have been rarely reported in the People's Republic of China. Among a collection of 659 E. coli isolates recovered from retail foods in Shaanxi Province, People's Republic of China, 223 cefoxitin-resistant and/or cefoperazone-resistant isolates were screened for ESBL production with the double disk diffusion test. The ESBL-producing isolates were characterized for antimicrobial resistance and the presence of blaTEM, blaSHV, and blaCTX-M genes. Isolates with blaCTX-M were further classified by PCR as having blaCTX-M-1, blaCTX-M-2, blaCTX-M-8, blaCTX-M-9, or blaCTX-M-25. One hundred forty-seven isolates were identified as ESBL positive. PCR detection revealed that 146 isolates (99.3%) contained the blaCTX-M gene. Among these isolates, 42 (28.8%) were positive for the enzyme CTX-M-1, 5 (3.4%) for CTX-M-2, and 99 (67.8%) for CTX-M-9. No CTX-M-8 and CTX-M-25 were found in this study. One hundred fifteen isolates (78.2%) were positive for the blaTEM gene, but blaSHV was not detected. Among the 147 ESBL-producing E. coli isolates, 75 (51.0%), 35 (23.8%), and 4 (2.7%) isolates were positive for blaTEM and blaCTX-M-9, blaTEM and blaCTX-M-1, and blaTEM and blaCTX-M-2, respectively. All of the 147 ESBL-producing isolates were resistant to three or more non-β-lactam antibiotics. This study provides evidence that foodborne E. coli can harbor ESBL-encoding genes. Thus, food could be a vehicle for the dissemination of ESBL-producing E. coli strains, a situation that requires surveillance and appropriate management strategies.

  17. Complete Sequence of Probiotic Symbioflor 2 Escherichia coli Strain G3/10 and Draft Sequences of Symbioflor 2 E. coli Strains G1/2, G4/9, G5, G6/7, and G8.

    Science.gov (United States)

    Zschüttig, Anke; Auerbach, Christian; Meltke, Simone; Eichhorn, Christin; Brandt, Manuela; Blom, Jochen; Goesmann, Alexander; Jarek, Michael; Scharfe, Maren; Zimmermann, Kurt; Wassenaar, Trudy M; Gunzer, Florian

    2015-03-05

    The complete genome of probiotic Escherichia coli strain G3/10 is presented here. In addition, the probiotic E. coli strains G1/2, G4/9, G5, G6/7, and G8 are presented in draft form. These six strains together comprise the probiotic product Symbioflor 2 (DSM 17252). Copyright © 2015 Zschüttig et al.

  18. Antibiotic resistance patterns of Escherichia coli strains isolated from surface water and groundwater samples in a pig production area

    Directory of Open Access Journals (Sweden)

    Roger Neto Schneider

    2009-09-01

    Full Text Available The use of antibiotics, so excessive and indiscriminate in intensive animal production, has triggered an increase in the number of resistant microorganisms which can be transported to aquatic environments. The aim of this study was to determine the profile of the antimicrobial resistance of samples of Escherichia coli isolated from groundwater and surface water in a region of pig breeding. Through the test of antimicrobial susceptibility, we analyzed 205 strains of E. coli. A high rate of resistance to cefaclor was observed, both in surface water (51.9% and groundwater (62.9%, while all samples were sensitive to amikacin. The percentages of multi-resistant samples were 25.96% and 26.73% in surface water and groundwater, respectively, while 19.23% and 13.86% were sensitive to all antibiotics tested. It was determined that the rate of multiple antibiotic resistance (MAR was 0.164 for surface water and 0.184 for groundwater. No significant differences were found in the profile of the antimicrobial resistance in strains of E. coli isolated in surface water and groundwater, but the index MAR calculated in certain points of groundwater may offer a potential risk of transmission of resistant genes.

  19. O-serotyping of Escherichia coli Strains isolated from Patients With Urinary Tract Infection in Southeast of Iran

    Directory of Open Access Journals (Sweden)

    Ahmad Rashki

    2014-11-01

    Full Text Available Background: Uropathogenic Escherichia coli (UPEC O-serogroups with their phylogenetic background are the most prevalent causes of urinary tract infections (UTIs. Objectives: The association of O types with phylogenetic background was assessed among E. coli isolates collected from patients with UTI. Patients and Methods: In this study, 186 patients with UTI, referred to two hospitals affiliated to Zabol University of Medical Sciences in southeast of Iran, were enrolled during January to July 2013. Phylogenetic groups and serotyping were performed using multiplex-PCR method. Results: A total of 100 E. coli strains were isolated from the urine samples. The most common types of O antigens were O2 (16.43%, O6 (16.43% and O18 (13.69%. The phylogenetic analysis showed that 63 O-antigen-positive isolates were mainly segregated from the phylogenetic group B2 (56% and the substantial prevalence (30% belonged to the phylogenetic group D. Conclusions: This was the first report of E. coli serotyping in patient with UTI from southeast of Iran as well as investigation of their relation with phylogenetic pattern by multiplex-PCR. Further studies from other parts of Iran and on other serotypes are recommended.

  20. Biofilm formation by asymptomatic and virulent urinary tract infectious Escherichia coli strains

    DEFF Research Database (Denmark)

    Hancock, Viktoria; Ferrieres, Lionel; Klemm, Per

    2007-01-01

    have investigated the biofilm-forming capacity on abiotic surfaces of groups of ABU strains and UPEC strains in human urine. We found that there is a strong bias; ABU strains were significantly better biofilm formers than UPEC strains. Our data suggest that biofilm formation in urinary tract infectious...

  1. Towards the in vivo production of tocotrienol compounds: engineering of a plasmid-free Escherichia coli strain for the heterologous synthesis of 2-methyl-6-geranylgeranyl-benzoquinol.

    Science.gov (United States)

    Ghanegaonkar, Shashank; Conrad, Jürgen; Beifuss, Uwe; Sprenger, Georg A; Albermann, Christoph

    2012-12-15

    The vitamin E family consists of 4 tocopherol and 4 tocotrienol compounds. During recent years, tocotrienols have gained increased interest due to their biological activities that are beyond the vitamin E activity. Here we report the engineering of plasmid-free Escherichia coli strains for an efficient synthesis of 2-methyl-6-geranylgeranyl-benzoquinol (MGGBQ), the central precursor for all four natural tocotrienol compounds. Heterologous genes needed for the in vivo synthesis of MGGBQ in E. coli (crtE, hpd, and hpt) were individually integrated into the chromosome of E. coli. The yield of MGGBQ after cultivation of the plasmid-free recombinant E. coli strain was significantly higher (604μg/gcdw) compared to an E. coli strain that carries these biosynthesis genes on a multi-copy expression plasmid (325μg/gcdw). Further chromosomal integration of an additional copy of the isopentenyl-diphosphate isomerase gene (idi) and a subsequent increase in expression level of the deoxy-xylulose synthase gene (dxs) increased the MGGBQ yield by 80% (1110μg/gcdw) and 135% (1425μg/gcdw), respectively. MGGBQ which accumulated in the membrane fraction of the recombinant E. coli cells was isolated and its structure was completely elucidated by 1D and 2D NMR and MS measurements. The engineered, plasmid-free E. coli strain is a promising host for the heterologous in vivo production of tocotrienol and its derivatives. Copyright © 2012 Elsevier B.V. All rights reserved.

  2. Short communication: The role of autoinducer 2 (AI-2) on antibiotic resistance regulation in an Escherichia coli strain isolated from a dairy cow with mastitis.

    Science.gov (United States)

    Xue, Ting; Yu, Lumin; Shang, Fei; Li, Wenchang; Zhang, Ming; Ni, Jingtian; Chen, Xiaolin

    2016-06-01

    Extended spectrum β-lactamase (ESBL)-positive Escherichia coli is a major etiological organism responsible for bovine mastitis. The autoinducer 2 (AI-2) quorum sensing system is widely present in many species of gram-negative and gram-positive bacteria and has been proposed to be involved in interspecies communication. In E. coli model strains, the functional mechanisms of AI-2 have been well studied; however, in clinical antibiotic-resistant E. coli strains, whether AI-2 affects the expression of antibiotic resistance genes has not been reported. In this study, we report that exogenous AI-2 increased the antibiotic resistance of a clinical E. coli strain isolated from a dairy cow with mastitis by upregulating the expression of TEM-type enzyme in an LsrR (LuxS regulated repressor)-dependent manner. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  3. In vitro antibacterial activity of medicinal plant extracts against Escherichia coli strains from human clinical specimens and interactions with antimicrobial drugs.

    Science.gov (United States)

    Ushimaru, P I; Barbosa, L N; Fernandes, A A H; Di Stasi, L C; Fernandes, A

    2012-01-01

    The biological properties of medicinal plants have been documented worldwide for many centuries. We aimed to evaluate interactions between crude extracts from Psidium guajava, Zingiber officinale, Cymbopogon citratus, Caryophyllus aromaticus, Mikania glomerata and Allium sativum samples and antimicrobial drugs against Escherichia coli strains. The susceptibility test performed was disc diffusion, and crude extracts were diluted (%v/v) into Müller-Hinton agar (MHA) at one quarter of the minimal inhibitory concentration for 90% (MIC(90%)) of E. coli strains found previously. Synergistic interactions were observed between C. citratus and polymyxin, and A. sativum extracts and gentamicin. The crude A. sativum extract was the only one that did not show any antagonism with the antimicrobial drugs. The results thus showed the potential use of these medicinal plants against E. coli strains, although antagonism with antimicrobial drugs is a negative aspect in the combined therapy of infectious diseases caused by E. coli.

  4. Expression of curli by Escherichia coli O157:H7 strains isolated from patients during outbreaks is different from similar strains isolated from leafy green production environments

    Directory of Open Access Journals (Sweden)

    Subbarao Venkata Ravva

    2016-12-01

    Full Text Available We previously reported that the strains of Escherichia coli O157:H7 (EcO157 that survived longer in austere soil environment lacked expression of curli, a fitness trait linked with intestinal colonization. In addition, the proportion of curli-positive variants of EcO157 decreased with repeated soil exposure. Here we evaluated 84 and 176 clinical strains from outbreaks and sporadic infections in the US, plus 211 animal fecal and environmental strains for curli expression. These shiga-toxigenic strains were from 328 different genotypes, as characterized by multi-locus variable-number tandem-repeat analysis (MLVA. More than half of the fecal strains (human and animal and a significant proportion of environmental isolates (82% were found to lack curli expression. EcO157 strains from several outbreaks linked with the consumption of contaminated apple juice, produce, hamburgers, steak and beef were also found to lack curli expression. Phylogenetic analysis of fecal strains indicates curli expression is distributed throughout the population. However, a significant proportion of animal fecal isolates (84% gave no curli expression compared to human fecal isolates (58%. In addition, analysis of environmental isolates indicated nearly exclusive clustering of curli expression to a single branch of the minimal spanning tree. This indicates that curli expression depends primarily upon the type of environmental exposure and the isolation source, although genotypic differences also contribute to clonal variation in curli. Furthermore, curli-deficient phenotype appears to be a selective trait for survival of EcO157 in agricultural environments.

  5. Simultaneous detection of Escherichia coli O157:H7, Listeria monocytogenes and Salmonella strains by real-time PCR.

    Science.gov (United States)

    Bhagwat, Arvind A

    2003-07-25

    A protocol enabling simultaneous detection of Escherichia coli O157:H7, Listeria monocytogenes and Salmonella strains was devised and evaluated using artificially contaminated fresh produce. Association of Official Analytical Chemists (AOAC)-approved polymerase chain reaction (PCR) detection methods for three human pathogens were modified to enable simultaneous and real-time detection with high throughput capability. The method includes a melting-curve analysis of PCR products, which serves as confirmatory test. The modified protocol successfully detected all three pathogens when fresh produce was washed with artificially contaminated water containing E. coli O157:H7 and S. typhimurium down to the predicted level of 1 to 10 cells/ml and L. monocytogenes at 1000 cells/ml. The ability to monitor several pathogens simultaneously will save time and increase our ability to assure food safety.

  6. Differential Gene Expression of Three Mastitis-Causing Escherichia coli Strains Grown under Planktonic, Swimming, and Swarming Culture Conditions.

    Science.gov (United States)

    Lippolis, John D; Brunelle, Brian W; Reinhardt, Timothy A; Sacco, Randy E; Thacker, Tyler C; Looft, Torey P; Casey, Thomas A

    2016-01-01

    Bacterial motility is thought to play an important role in virulence. We have previously shown that proficient bacterial swimming and swarming in vitro is correlated with the persistent intramammary infection phenotype observed in cattle. However, little is known about the gene regulation differences important for different motility phenotypes in Escherichia coli. In this work, three E. coli strains that cause persistent bovine mastitis infections were grown in three media that promote different types of motility (planktonic, swimming, and swarming). Using whole-transcriptome RNA sequencing, we identified a total of 935 genes (~21% of the total genome) that were differentially expressed in comparisons of the various motility-promoting conditions. We found that approximately 7% of the differentially expressed genes were associated with iron regulation. We show that motility assays using iron or iron chelators confirmed the importance of iron regulation to the observed motility phenotypes. Because of the observation that E. coli strains that cause persistent infections are more motile, we contend that better understanding of the genes that are differentially expressed due to the type of motility will yield important information about how bacteria can become established within a host. Elucidating the mechanisms that regulate bacterial motility may provide new approaches in the development of intervention strategies as well as facilitate the discovery of novel diagnostics and therapeutics. IMPORTANCE Bacteria can exhibit various types of motility. It is known that different types of motilities can be associated with virulence. In this work, we compare gene expression levels in bacteria that were grown under conditions that promoted three different types of E. coli motility. Better understanding of the mechanisms of how bacteria can cause an infection is an important first step to better diagnostics and therapeutics.

  7. Ciliates rapidly enhance the frequency of conjugation between Escherichia coli strains through bacterial accumulation in vesicles

    OpenAIRE

    Matsuo, Junji; Oguri, Satoshi; Nakamura, Shinji; Hanawa, Tomoko; Fukumoto, Tatsuya; Hayashi, Yasuhiro; Kawaguchi, Kouhei; Mizutani, Yoshihiko; Yao, Takashi; Akizawa, Kouzi; Suzuki, Haruki; Simizu, Chikara; MATSUNO, Kazuhiko; Kamiya, Shigeru; Yamaguchi, Hiroyuki

    2010-01-01

    The mechanism underlying bacterial conjugation through protozoa was investigated. Kanamycin-resistant Escherichia coli SM10λ+ carrying pRT733 with TnphoA was used as donor bacteria and introduced by conjugation into ciprofloxacin-resistant E. coli clinical isolate recipient bacteria. Equal amounts of donor and recipient bacteria were mixed together in the presence or absence of protozoa (ciliates, free-living amoebae, myxamoebae) in Page's amoeba saline for 24 h. Transconjugants were selected...

  8. A draft genome of Escherichia coli sequence type 127 strain 2009-46

    OpenAIRE

    Darling, Aaron E; McKinnon, Jessica; Worden, Paul; Santos, Jerran; Charles, Ian G; Chowdhury, Piklu Roy; Djordjevic, Steven P

    2014-01-01

    Background Escherichia coli are a frequent cause of urinary tract infections (UTI) and are thought to have a foodborne origin. E. coli with sequence type 127 (ST127) are emerging pathogens increasingly implicated as a cause of urinary tract infections (UTI) globally. A ST127 isolate (2009-46) resistant to ampicillin and trimethoprim was recovered from the urine of a 56 year old patient with a UTI from a hospital in Sydney, Australia and was characterised here. Results We sequenced the genome ...

  9. Characterization of IcmF of the type VI secretion system in an avian pathogenic Escherichia coli (APEC) strain.

    Science.gov (United States)

    de Pace, Fernanda; Boldrin de Paiva, Jacqueline; Nakazato, Gerson; Lancellotti, Marcelo; Sircili, Marcelo Palma; Guedes Stehling, Eliana; Dias da Silveira, Wanderley; Sperandio, Vanessa

    2011-10-01

    The intracellular multiplication factor (IcmF) protein is a component of the recently described type VI secretion system (T6SS). IcmF has been shown to be required for intra-macrophage replication and inhibition of phagosome-lysosome fusion in Legionella pneumophila. In Vibrio cholerae it is involved in motility, adherence and conjugation. Given that we previously reported that two T6SS genes (hcp and clpV) contribute to the pathogenesis of a septicaemic strain (SEPT362) of avian pathogenic Escherichia coli (APEC), we investigated the function of IcmF in this strain. Further elucidation of the virulence mechanisms of APEC is important because this pathogen is responsible for financial losses in the poultry industry, and is closely related to human extraintestinal pathogenic E. coli (ExPEC) strains, representing a potential zoonotic risk, as well as serving as a reservoir of virulence genes. Here we show that an APEC icmF mutant has decreased adherence to and invasion of epithelial cells, as well as decreased intra-macrophage survival. The icmF mutant is also defective for biofilm formation on abiotic surfaces. Additionally, expression of the flagella operon is decreased in the icmF mutant, leading to decreased motility. The combination of these phenotypes culminates in this mutant being altered for infection in chicks. These results suggest that IcmF in APEC may play a role in disease, and potentially also in the epidemiological spread of this pathogen through enhancement of biofilm formation.

  10. Epidemiology of Antimicrobial Resistance among Escherichia coli Strains in Trans-Nzoia County, Kenya

    Directory of Open Access Journals (Sweden)

    Collins Kibenei Kipkorir, Philip Bett, Patrick O. Onyango

    2016-09-01

    Full Text Available Objective: This study aimed to determine prevalence, antimicrobial susceptibility profile and the genetic basis to antimicrobial resistance, targeting blaTEM gene expression of diarrheagenic Escherichia coli among patients suffering from gastroenteritis in Kitale County Referral Hospital. Methods: A cross-sectional study design was adopted. A total of 103 fecal specimens were collected from participants ranging in age from two weeks to 82 years. E. coli was isolated and identified based on phenotypic and biochemical properties. Antimicrobial susceptibility was determined by Kirby-Bauer disk diffusion method. Polymerase chain reaction was used to detect the presence of blaTEM gene. Results: The prevalence of E. coli was 90.2% and age of the patient explained 53% of variation in prevalence. Isolates of diarrheagenic E. coli showed varied degree of susceptibility with sulfamethoxazole at 97%, co-trimoxazole 96%, ampicillin 84%, chloramphenicol 27%, tetracycline 16%, kanamycin 10% and streptomycin 9%. However, E. coli was highly sensitive to gentamicin at 96.8%. Approximately 42.2% of E. coli isolates were multidrug resistant to sulfamethoxazole, co-trimoxazole, ampicillin, chloramphenicol, tetracycline, kanamycin and streptomycin. All isolates that were resistant to ampicillin harbored blaTEM gene suggesting genetic mediation. Conclusion: The observed pattern of resistance to antibiotics points to the need to regulate their use and arrest buildup of resistant genes within the population. J Microbiol Infect Dis 2016;6(3: 107-112

  11. Evaluation of the Antibiotic Resistance and Virulence of Escherichia coli Strains Isolated from Chicken Carcasses in 2007 and 2013 from Paraná, Brazil.

    Science.gov (United States)

    Koga, Vanessa L; Rodrigues, Gabriela R; Scandorieiro, Sara; Vespero, Eliana C; Oba, Alexandre; de Brito, Benito G; de Brito, Kelly C T; Nakazato, Gerson; Kobayashi, Renata K T

    2015-06-01

    The frequent use of antimicrobials in commercial poultry production has raised concerns regarding the potential impact of antimicrobials on human health due to selection for resistant bacteria. Several studies have reported similarities between extraintestinal pathogenic Escherichia coli (ExPEC) strains isolated from birds and humans, indicating that these contaminant bacteria in poultry may be linked to human disease. The aim of our study was to analyze the frequency of antimicrobial resistance and virulence factors among E. coli strains isolated from commercial chicken carcasses in Paraná, Brazil, in 2007 and 2013. A total of 84 E. coli strains were isolated from chicken carcasses in 2007, and 121 E. coli strains were isolated in 2013. Polymerase chain reaction was used to detect virulence genes (hlyF, iss, ompT, iron, and iutA) and to determine phylogenetic classification. Antimicrobial susceptibility testing was performed using 15 antimicrobials. The strains were also confirmed as extended-spectrum β-lactamase (ESBL)-producing E. coli with phenotypic and genotypic tests. The results indicated that our strains harbored virulence genes characteristic of ExPEC, with the iutA gene being the most prevalent. The phylogenetic groups D and B1 were the most prevalent among the strains isolated in 2007 and 2013, respectively. There was an increase in the frequency of resistance to a majority of antimicrobials tested. An important finding in this study was the large number of ESBL-producing E. coli strains isolated from chicken carcasses in 2013, primarily for the group 2 cefotaximase (CTX-M) enzyme. ESBL production confers broad-spectrum resistance and is a health risk because ESBL genes are transferable from food-producing animals to humans via poultry meat. These findings suggest that our strains harbored virulence and resistance genes, which are often associated with plasmids that can facilitate their transmission between bacteria derived from different hosts

  12. [Resistant phenotypes of Escherichia coli strains responsible for urinary tract infection in the laboratory of the University Hospital Joseph Raseta Befelatanana, Antananarivo].

    Science.gov (United States)

    Rakotovao-Ravahatra, Zafindrasoa Domoina; Randriatsarafara, Fidiniaina Mamy; Rasoanandrasana, Saïda; Raverohanta, Léa; Rakotovao, Andriamiadana Luc

    2017-01-01

    Urinary tract infection caused by Escherichia coli frequently occurs in the hospital environment. This study aims to describe resistant phenotypes of Escherichia coli strains to monitor their occurrence. We conducted a descriptive retrospective study of 102 Escherchia coli strains responsible for urinary tract infection in the laboratory of the University Hospital Joseph Raseta Befelatanana, Antananarivo from January 2014 to October 2016. Beta-lactam antibiotic resistance screening identified high-level penicillinases 50% (n=51), Escherichia coli producing extended-spectrum beta-lactamases (ESBLs) 22.5% (n=23), high-level cephalosporinases 14.7% (n=15), penicillinases low level 5.9% (n=6), wild type strains 5.9% (n=6) and a strain ofEscherichia coli emerging strain high-level resistance. Aminoglycosides resistance was identified in 58 (56.9%) wild type phenotype, 29 (28.4%) strains sensitive to amikacin and 15 (14.7%) resistant to all aminoglycosides. Fluoroquinolones resistance was identified in 52 (51%) wild type strains, 9 (8.8%) strains sensitive to ciprofloxacin and 41 (40.2%) resistant to all fluoroquinolones. Women (25, 7%) (p= 0.25, NS), patients more than 60 years (38.7%) (p=0.02), patients hospitalized in the Department of Nephrology (53.8%) (p=0.04), with urinary disorder and kidney disease (29, 7%) (p= 0.2, NS) were the most affected by E-ESBL. Based on high multidrug resistance in Escherichia coli strains guidelines for the empirical treatment of urinary tract infections need to be revised.

  13. Extract of Clinopodium bolivianum protects against E. coli invasion of uroepithelial cells.

    Science.gov (United States)

    Mohanty, Soumitra; Kamolvit, Witchuda; Zambrana, Silvia; Sandström, Corine; Gonzales, Eduardo; Östenson, Claes-Göran; Brauner, Annelie

    2017-02-23

    Clinopodium bolivianum is a South American plant with anti-inflammatory and anti-infective activities. The increasing antibiotic resistance urges for alternative therapy. Based on its use in traditional medicine, we investigated the effect of C. bolivianum on the ability to defend bladder epithelial cells from E. coli infection. The extract was analyzed by LC-MS. Bladder epithelial cell lines T24 and 5637 and uropathogenic E. coli No. 12, its isogenic mutant WE16 csgBA bscA::Cm and CFT073 were used to investigate the effect of C. bolivianum on uroepithelial infection. Bacterial adherence and invasion to cells treated with C. bolivianum were analyzed. Expression of uroplakin 1a, β1 integrin, caveolin-1, IL-8 and antimicrobial peptides in response to C. bolivianum treatment was assessed using RT-PCR. Protein expression was confirmed by Western blot analysis or ELISA. The antimicrobial effects of C. bolivianum on bacteria and fungus were investigated using minimum inhibitory concentration. Furthermore, the formation of biofilm was investigated with crystal violet assay. C. bolivianum extract consisted of more than 70 different types of phytochemicals including sugars and phenolic compounds. The extract decreased the uroplakin 1a expression and E. coli adhesion and invasion of uroepithelial cells while up-regulated caveolin-1. In uninfected C. bolivianum treated cells, IL-8 was lower than in non-treated cells. In infected cells, however, no difference was observed between treated and non-treated cells. Further, C. bolivianum treatment reduced uropathogenic E. coli (UPEC) biofilms but did not inhibit bacterial growth. Our results show that C. bolivianum has a protective role on bladder epithelial cells against UPEC infection by decreasing the bacterial adhesion, invasion and biofilm formation. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

  14. Molecular characterization of antibiotic resistance in Escherichia coli strains from a dairy cattle farm and its surroundings.

    Science.gov (United States)

    Navajas-Benito, Enrique Víctor; Alonso, Carla Andrea; Sanz, Susana; Olarte, Carmen; Martínez-Olarte, Roberto; Hidalgo-Sanz, Sara; Somalo, Sergio; Torres, Carmen

    2017-01-01

    This study describes the phenotypic and genotypic characteristics of 78 genetically different Escherichia coli recovered from air and exudate samples of a dairy cattle farm and its surroundings in Spain, in order to gain insight into the flow of antimicrobial resistance through the environment and food supply. Antimicrobial resistance was detected in 21.8% of the 78 E. coli isolates analyzed (resistance for at least one of the 14 agents tested). The highest resistance rates were recorded for ampicillin, nalidixic acid, trimethoprim/sulfamethoxazole and tetracycline. The resistance genes detected were as follows (antibiotic (number of resistant strains), gene (number of strains)): ampicillin (9), blaTEM-1 (6); tetracycline (15), tet(A) (7), tet(B) (4), tet(A) + tet(B) (1); chloramphenicol (5), cmlA (2), floR (2); trimethoprim/sulfamethoxazole (10), sul2 (4), sul1 (3), sul3 (2), sul1 + sul2 (1); gentamicin-tobramycin (1), ant(2″) (1). About 14% of strains showed a multidrug-resistant phenotype and, of them, seven strains carried class 1 integrons containing predominantly the dfrA1-aadA1 array. One multidrug-resistant strain was found in both inside and outside air, suggesting that the airborne spread of multidrug-resistant bacteria from the animal housing facilities to the surroundings is feasible. This study gives a genetic background of the antimicrobial resistance problem in a dairy cattle farm and shows that air can act as a source for dissemination of antimicrobial-resistant bacteria. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  15. IncFII Conjugative Plasmid-Mediated Transmission of blaNDM-1 Elements among Animal-Borne Escherichia coli Strains.

    Science.gov (United States)

    Lin, Dachuan; Xie, Miaomiao; Li, Ruichao; Chen, Kaichao; Chan, Edward Wai-Chi; Chen, Sheng

    2017-01-01

    This study aims to investigate the prevalence and transmission dynamics of the bla NDM-1 gene in animal Escherichia coli strains. Two IncFII bla NDM-1 -encoding plasmids with only minor structural variation in the MDR region, pHNEC46-NDM and pHNEC55-NDM, were found to be responsible for the transmission of bla NDM-1 in these strains. The bla NDM-1 gene can be incorporated into plasmids and stably inherited in animal-borne E. coli strains that can be maintained in animal gut microflora even without carbapenem selection pressure. Copyright © 2016 American Society for Microbiology.

  16. In vitro testing of the some antibiotics efficiency on some E. coli strains isolated from avian farms

    Directory of Open Access Journals (Sweden)

    Veturia-Ileana Nueleanu,

    2008-06-01

    Full Text Available For broiler chickens, a major mortality cause on the entire exploitation period is represented by the collibacilar infections, which need a correct and efficient treatment. The mortality in 94 broiler chickens was studied, between three and thirty days of age, from four avian farms from Satu-Mare county, isolating and identifying 32 Escherichia coli strains in pure culture. The testing of sensitivity to antibiotics of the isolated germs was made through the difusimethric method, revealing a decreased efficiency to Oxitetracyclin, Amoxicyllin and Erithromycin, while in the case of Amoxicyllin + Clavulanic acid, Florfenicol and Gentamycin a good sensitivity was observed.

  17. Discrimination of enterohemorrhagic Escherichia coli (EHEC) from non-EHEC strains based on detection of various combinations of type III effector genes.

    Science.gov (United States)

    Delannoy, Sabine; Beutin, Lothar; Fach, Patrick

    2013-10-01

    Enterohemorrhagic Escherichia coli (EHEC) strains comprise a subgroup of Shiga-toxin (Stx)-producing E. coli (STEC) and are characterized by a few serotypes. Among these, seven priority STEC serotypes (O26:H11, O45:H2, O103:H2, O111:H8, O121:H19, O145:H28, and O157:H7) are most frequently implicated in severe clinical illness worldwide. Currently, standard methods using stx, eae, and O-serogroup-specific gene sequences for detecting the top 7 EHEC serotypes bear the disadvantage that these genes can be found in non-EHEC strains as well. Here, we explored the suitability of ureD, espV, espK, espN, Z2098, and espM1 genes and combinations thereof as candidates for a more targeted EHEC screening assay. For a very large panel of E. coli strains (n = 1,100), which comprised EHEC (n = 340), enteropathogenic E. coli (EPEC) (n = 392), STEC (n = 193), and apathogenic strains (n = 175), we showed that these genetic markers were more prevalent in EHEC (67.1% to 92.4%) than in EPEC (13.3% to 45.2%), STEC (0.5% to 3.6%), and apathogenic E. coli strains (0 to 2.9%). It is noteworthy that 38.5% of the EPEC strains that tested positive for at least one of these genetic markers belonged to the top 7 EHEC serotypes, suggesting that such isolates might be Stx-negative derivatives of EHEC. The associations of espK with either espV, ureD, or Z2098 were the best combinations for more specific and sensitive detection of the top 7 EHEC strains, allowing detection of 99.3% to 100% of these strains. In addition, detection of 93.7% of the EHEC strains belonging to other serotypes than the top 7 offers a possibility for identifying new emerging EHEC strains.

  18. Whole genome sequencing of diverse Shiga toxin-producing and non-producing Escherichia coli strains reveals a variety of virulence and novel antibiotic resistance plasmids.

    Science.gov (United States)

    Losada, Liliana; DebRoy, Chitrita; Radune, Diana; Kim, Maria; Sanka, Ravi; Brinkac, Lauren; Kariyawasam, Subhashinie; Shelton, Daniel; Fratamico, Pina M; Kapur, Vivek; Feng, Peter C H

    2016-01-01

    The genomes of a diverse set of Escherichia coli, including many Shiga toxin-producing strains of various serotypes were determined. A total of 39 plasmids were identified among these strains, and many carried virulence or putative virulence genes of Shiga toxin-producing E. coli strains, virulence genes for other pathogenic E. coli groups, and some had combinations of these genes. Among the novel plasmids identified were eight that carried resistance genes to aminoglycosides, carbapenems, penicillins, cephalosporins, chloramphenicol, dihydrofolate reductase inhibitors, sulfonamides, tetracyclines and resistance to heavy metals. Two of the plasmids carried six of these resistance genes and two novel IncHI2 plasmids were also identified. The results of this study showed that plasmids carrying diverse resistance and virulence genes of various pathogenic E. coli groups can be found in E. coli strains and serotypes regardless of the isolate's source and therefore, is consistent with the premise that these mobile elements carrying these traits may be broadly disseminated among E. coli. Published by Elsevier Inc.

  19. Comparative Evaluation of the Modulation of Antibiotic-Activity against Strains of Escherichia coli and Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Henrique D. M. Coutinho

    2015-09-01

    Full Text Available Introduction: Combining multiple drugs is an strategy used to combat the dissemination of pathogenic and drug resistant bacteria. However, the misuse of these drugs against bacteria have caused the selection of more resistant specimens called multidrug-resistant bacteria. Objective: In this work we evaluated the antibiotic activity of claritromicin, gentamicin, ciprofloxacin and imipenen, alone or associating one by one, against strains of Escherichia coli and Staphylococcus aureus. Material and methods: The minimal inhibitory concentration (mic was performed us­ing the microdilution assay. Based in the mic values, the antibiotic effect of the drugs alone and in association were determined. Results: The association between the drugs demonstrated the synergism against the bacterial strains. Conclusion: The use of the combined antibiotic-therapy can be positively performed, but additional studies have to be conducted first for proving that its use is safe.

  20. In vitro efficacy of several disinfectants against Salmonella enterica serovar Enteritidis and Escherichia coli strains from poultry

    Directory of Open Access Journals (Sweden)

    Sonia Martínez-Martínez

    2016-01-01

    Full Text Available ABSTRACT The efficacy of 28 individual or blended disinfectants against avian Salmonella enterica serovar Enteritidis and Escherichia coli strains was determined. An in vitro test in the presence and absence of serum as source of organic material was conducted. Povidone-iodine (releasing 1% available iodine, 1% potassium permanganate, 70% ethanol, 2% chlorhexidine digluconate and three commercial formulations based on quaternary ammonium compounds + formaldehyde or cresol derivates were the most effective against all strains tested and reduced bacterial counts by more than 106 times (6-log10 regardless of the presence of organic matter. These commercial compounds as well as ethanol and chlorhexidine among the individual substances tested might be helpful in the adoption of environmental control measures against these two enterobacteria in poultry industry.

  1. Genetic Virulence Profile of Enteroaggregative Escherichia coli Strains Isolated from Danish Children with Either Acute or Persistent Diarrhea

    DEFF Research Database (Denmark)

    Hebbelstrup Jensen, Betina; Poulsen, Anja; Hebbelstrup Rye Rasmussen, Stig

    2017-01-01

    with an expected severe disease course. Questionnaires answered by parents provided information regarding duration of diarrhea and presence of blood or mucus. A total of 295 EAEC strains were collected from children with acute (≤7 days) and persistent diarrhea (≥14 days) and were compared by using multiplex PCR......Enteroaggregative Escherichia coli (EAEC) is frequently found in diarrheal stools worldwide. It has been associated with persistent diarrhea, weight loss, and failure to thrive in children living in developing countries. A number of important EAEC virulence genes are identified; however......, their roles in acute and persistent diarrhea have not been previously investigated. The aim of this study was to identify specific EAEC virulence genes associated with duration and type of diarrhea in Danish children. We aimed to improve the current diagnostics of EAEC and enable targeting of strains...

  2. [Correlation between multiple antibiotic resistance and heavy-metal tolerance among some E.coli strains isolated from polluted waters].

    Science.gov (United States)

    Lazăr, Veronica; Cernat, Ramona; Balotescu, Carmen; Cotar, Ani; Coipan, Elena; Cojocaru, Cristina

    2002-01-01

    Self-transmissible plasmids conferring multiple antibiotic resistance are wide-spread in coliforms populations. In soil and water, multiple antibiotic resistance is clearly associated with resistance/tolerance to heavy-metals (Hg2+, Cu2+, Pb2+, Zn2+, Ca2+). For different genera the genes for heavy-metals resistance are often plasmid encoded. Since these genes are clustered on the same plasmids, heavy-metals and drugs are environmental factors which exert a selective pressure for the populations of these plasmid-harboring bacteria. The aim of this preliminary study was to find possible correlation between resistance genotype determined by genetic analysis and antibiotic and heavy-metal resistance patterns of 12 E. coli strains isolated from chronically polluted waters. Antimicrobial susceptibility testing was performed for ampicillin, tetracycline, gentamycin, kanamycin, chloramphenicol, ceftazidime and cefotaxime by standard disk diffusion Kirby-Bauer method following NCCLS recommendations. These antibiotics were chosen because of their wide-spread use and importance in the treatment of Gram-negative bacterial infections. MICs values of antibiotics and heavy-metals were determined by dilution method in Mueller-Hinton broth using an inoculum of about 1-2 x 10(8) CFU/ml. The concentration range for antimicrobials and heavy-metals salts (CuSO4, CdCl2, Co(NO3)2, Cr(NO3)3, HgCl2, NiCl2 and ZnSO4) was 0.06-64 [symbol: see text] g/ml, 0.5-256 [symbol: see text] g/ml respectively. Plasmid DNA was isolated from E. coli strains by an alkaline lysis. Genetic characterization was performed by agarose gel electrophoresis and spectrophotometric analysis. All strains are multiple antibiotic resistant, 16% of them being resistant to 3, 4 and 6 antibiotics, 32% to 5 and 8% to all 7 antibiotics, respectively. Multiple tolerance to high levels of Cd2+, Cu2+, Cr3+ and Ni2+ was common among multiple antibioresistant strains. Screening for plasmids relieved the presence of several

  3. 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

  4. Influenza A virus infection of intestinal epithelial cells enhances the adhesion ability of Crohn's disease associated Escherichia coli strains.

    Science.gov (United States)

    Aleandri, Marta; Conte, Maria Pia; Simonetti, Giovanna; Panella, Simona; Celestino, Ignacio; Checconi, Paola; Marazzato, Massimiliano; Longhi, Catia; Goldoni, Paola; Nicoletti, Mauro; Barnich, Nicolas; Palamara, Anna Teresa; Schippa, Serena; Nencioni, Lucia

    2015-01-01

    Modifications of intestinal glycoreceptors expression, in particular CEACAM6, typically found in ileal Crohn's disease (CD), favor, among the commensal species of microbiota, the enrichment in Escherichia coli. Removal of protein glycosidic residues by neuraminidase, a sialidase typical of influenza virus, increases adhesion ability of Escherichia coli to Caco-2 intestinal cells. In this study we investigated whether influenza virus infection of human intestinal epithelial cells could influence the adhesiveness of different Escherichia coli strains isolated from CD patients by altering surface glycoreceptors. Influenza virus infection of intestinal cells increased exposure of galactose and mannose residues on the cell surface. In particular, glycoreceptors Thomsen-Friedenreich and CEACAM6 were over-expressed in influenza virus infected cells. In the same experimental conditions, a significant increase in bacterial adhesiveness was observed, independently of their own adhesive ability. The increase was reverted by treatment with anti-TF and anti-CEACAM6 antibodies. Interestingly, influenza virus was able to efficiently replicate in human primary intestinal cells leading to TF exposure. Finally, intestinal infected cells produced high levels of pro-inflammatory cytokines compared to control. Overall these data suggest that influenza virus infection, could constitute an additional risk factor in CD patients.

  5. THE RESISTANCE TO ANTIBIOTICS IN STRAINS OF E. COLI AND ENTEROCOCCUS SP. ISOLATED FROM RECTAL SWABS OF LAMBS AND CALVES

    Directory of Open Access Journals (Sweden)

    IVANA NOVÁKOVÁ

    2009-10-01

    Full Text Available he aim of this study was to determine the prevalence and antibiotic resistance of enterococcii and E. coli strains isolated from dairy calves and lambs. Susceptibilities of isolated enterococci were tested using the disk diffusion method. The interpretation of inhibition zones around the disks was according to CLSI 2004 Performance standards for antimicrobial susceptibility testing. In our study, all isolates (E. coli and enterococci were multiresistant (100% to tetracycline, streptomycin and compound sulphonamides. Lower levels of resistance to enrofloxacin were noted. Antimicrobial resistance profiles of Enterococcus sp. isolated from lambs indicated that the highest percentage of susceptibility was exhibited to tetracycline (100% and streptomycin (100% and compound sulphonamides (100%. The intermediate resistance was exhibited against compound enrofloxacin (80%. The high frequencies of resistant isolates of Enterococcus sp. from calves were documented in tetracycline (100%, streptomycin (100% and compound sulphonamides (100% and enrofloxacin (50%. The high percentage (compound sulphonamides-100%, tetracycline-100% and streptomycin- 100% of multiresistant E. coli (isolates from dairy calves was noticed. There were no significant correlations between groups.

  6. High Incidence of Escherichia coli Strains Coharboringmcr-1andblaNDMfrom Chickens.

    Science.gov (United States)

    Liu, Bao-Tao; Song, Feng-Jing; Zou, Ming; Zhang, Qi-Di; Shan, Hu

    2017-03-01

    This study investigated the characteristics of Escherichia coli isolates carrying mcr-1-bla NDM from a chicken farm in China. Of the 78 E. coli isolates, 21 clonally unrelated isolates carried mcr-1-bla NDM Diverse IncI2 plasmids disseminated mcr-1 , while the dissemination of bla NDM was mediated by diverse IncB/O plasmids. More striking was the colocalization of resistance genes mcr-1 and bla NDM-4 in an IncHI2/ST3 plasmid, which might pose a great challenge for public health. Copyright © 2017 American Society for Microbiology.

  7. Overexpression of Pseudomonas aeruginosa LpxC with its inhibitors in an acrB-deficient Escherichia coli strain.

    Science.gov (United States)

    Gao, Ning; McLeod, Sarah M; Hajec, Laurel; Olivier, Nelson B; Lahiri, Sushmita D; Bryan Prince, D; Thresher, Jason; Ross, Philip L; Whiteaker, James D; Doig, Peter; Li, Amanda Haixi; Hill, Pamela J; Cornebise, Mark; Reck, Folkert; Hale, Michael R

    2014-12-01

    In Gram-negative bacteria, the cell wall is surrounded by an outer membrane, the outer leaflet of which is comprised of charged lipopolysaccharide (LPS) molecules. Lipid A, a component of LPS, anchors this molecule to the outer membrane. UDP-3-O-(R-3-hydroxymyristoyl)-N-acetylglucosamine deacetylase (LpxC) is a zinc-dependent metalloamidase that catalyzes the first committed step of biosynthesis of Lipid A, making it a promising target for antibiotic therapy. Formation of soluble aggregates of Pseudomonas aeruginosa LpxC protein when overexpressed in Escherichia coli has limited the availability of high quality protein for X-ray crystallography. Expression of LpxC in the presence of an inhibitor dramatically increased protein solubility, shortened crystallization time and led to a high-resolution crystal structure of LpxC bound to the inhibitor. However, this approach required large amounts of compound, restricting its use. To reduce the amount of compound needed, an overexpression strain of E. coli was created lacking acrB, a critical component of the major efflux pump. By overexpressing LpxC in the efflux deficient strain in the presence of LpxC inhibitors, several structures of P. aeruginosa LpxC in complex with different compounds were solved to accelerate structure-based drug design. Copyright © 2014 Elsevier Inc. All rights reserved.

  8. Genetic relatedness of commensal Escherichia coli from nursery pigs in intensive pig production in Denmark and molecular characterization of genetically different strains

    DEFF Research Database (Denmark)

    Herrero Fresno, Ana; Larsen, Inge; Olsen, John Elmerdahl

    2015-01-01

    AIMS: To determine the genetic relatedness and the presence of virulence and antibiotic resistance genes in commensal Escherichia coli from nursery pigs in Danish intensive production. METHODS AND RESULTS: The genetic diversity of 1000 E. coli strains randomly picked (N = 50 isolates) from cultured......-producing genes were observed in 20 isolates. CONCLUSIONS: A low genetic diversity was found in commensal gut E. coli from nursery pigs in Denmark. No correlation was observed between REP-profiles, ST-types and resistance/virulence patterns. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first study analysing...... in depth the genetic variability of commensal E. coli from pigs in Danish intensive pig production. A tendency for higher diversity was observed with in nursery pigs that were treated with zinc oxide only, in absence of other antimicrobials. Strains with potential to disseminate virulence and antibiotic...

  9. Virulence Markers and Phylogenetic Analysis of Escherichia coli Strains with Hybrid EAEC/UPEC Genotypes Recovered from Sporadic Cases of Extraintestinal Infections.

    Science.gov (United States)

    Lara, Flaviane B M; Nery, Danielly R; de Oliveira, Pâmela M; Araujo, Mayana L; Carvalho, Fabiana R Q; Messias-Silva, Lorena C F; Ferreira, Leonardo B; Faria-Junior, Celio; Pereira, Alex L

    2017-01-01

    Virulence genes from different E. coli pathotypes are blended in hybrid strains. E. coli strains with hybrid enteroaggregative/uropathogenic (EAEC/UPEC) genotypes have sporadically emerged causing outbreaks of extraintestinal infections, however their association with routine infections is yet underappreciated. We assessed 258 isolates of E. coli recovered from 86 consecutive cases of extraintestinal infections seeking EAEC and hybrid genotype (EAEC/UPEC) strains. Extensive virulence genotyping was carried out to detect 21 virulence genes, including molecular predictors of EAEC and UPEC strains. Phylogenetic groups and sequence types (STs) were identified, as well as it was performed phylogenetic analyses in order to evaluate whether hybrid EAEC/UPEC strains belonged to intestinal or extraintestinal lineages of E. coli. Adhesion assays were performed to evaluate the biofilm formation by hybrid strains in human urine and cell culture medium (DMEM). Molecular predictors of UPEC were detected in more than 70% of the strains (chuA in 85% and fyuA in 78%). Otherwise, molecular predictors of EAEC (aatA and aggR) were detected in only 3.4% (9/258) of the strains and always along with the UPEC predictor fyuA. Additionally, the pyelonephritis-associated pilus (pap) gene was also detected in all of the hybrid EAEC/UPEC strains. EAEC/UPEC strains were recovered from two cases of community-onset urinary tract infections (UTI) and from a case of bacteremia. Analyses revealed that hybrid EAEC/UPEC strains were phylogenetically positioned in two different clades. Two representative strains, each recovered from UTI and bacteremia, were positioned into a characteristic UPEC clade marked by strains belonging to phylogenetic group D and ST3 (Warwick ST 69). Another hybrid EAEC/UPEC strain was classified as phylogroup A-ST478 and positioned in a commensal clade. Hybrid EAEC/UPEC strains formed biofilms at modest, but perceptible levels either in DMEM or in urine samples. We showed

  10. Complete genome sequences of two Escherichia coli O145:H28 outbreak strains of food origin

    Science.gov (United States)

    Although serotype O157:H7 is the predominant enterohemorrhagic Escherichia coli (EHEC), outbreaks of non-O157 EHEC that cause severe foodborne illness, including hemolytic uremic syndrome have increased worldwide. O145 is recognized as one of the six non-O157 serotypes that are most frequently assoc...

  11. The role of entero-aggregative Escherichia coli (EAEC) strains on ...

    African Journals Online (AJOL)

    This showed that intestinal parasites are also important factor in the etiology of diarrhea in this area. There was mixed infection between parasites and EAEC in 5 test subjects in Bayelsa State, but none in the other States and also none from the control. The entero-aggregative E. coli showed marked resistance to ...

  12. Phenotypic assay of adherent E. coli strains using hep-2 cells on ...

    African Journals Online (AJOL)

    ... this showed that intestinal parasites are also important factor in the etiology of diarrhea in this area. The parasites were mostly seen in older children from both groups and this might be attributed to their wandering, playing and eating habits. No mixed infection between parasites, parasite and adherent E. coli or between ...

  13. Optimizing Membrane Protein Overexpression in the Escherichia coli strain Lemo21(DE3)

    NARCIS (Netherlands)

    Schlegel, Susan; Lofblom, John; Lee, Chiara; Hjelm, Anna; Klepsch, Mirjam; Strous, Marc; Drew, David; Slotboom, Dirk Jan; de Gier, Jan-Willem

    2012-01-01

    Escherichia coli BL21(DE3) is widely used to overexpress proteins. In this overexpression host, the gene encoding the target protein is located on a plasmid and is under control of the T7 promoter, which is recognized exclusively by the T7 RNA polymerase (RNAP). The 17 RNAP gene is localized on the

  14. Changes in the proteome of Mastitis-causing escherichia coli strains that affect pathogenesis

    Science.gov (United States)

    Escherichia coli is a leading cause of bacterial mastitis in dairy cattle. Milk is the environment in which bacteria must grow to establish an infection of the mammary gland. However, milk is not a rich growth media for bacteria. In fact, milk naturally contains many mechanisms to inhibit bacterial ...

  15. Regulation of the L-arabinose operon in strains of Escherichia coli containing ColE1-ara hybrid plasmids.

    Science.gov (United States)

    Wallace, L J; Wilcox, G

    1979-06-20

    Hybrid plasmids were constructed from fragments of F'ara episomes formed by the restriction endonuclease EcoRI and a linear form of the plasmid ColE1 created by cleavage with EcoRI. Hybrid plasmids were constructed containing the entire ara region or the ara region with various parts deleted. E. coli K12 host strains were constructed which contained different deletions of the ara region. The hybrid plasmids were transferred to those strains whose ara deletion complemented that of the plasmid. The initial differential rates of synthesis of L-arabinose isomerase, the product of the araA gene, were determined for the Ara+, plasmid containing strains. These studies demonstrated that strains containing delta(araOIBA)718 produce elevated levels of araC protein, suggesting the araC promoter has been altered by this deletion. Evidence is also presented which suggests that araC protein activates the ara-BAD operon to higher levels when it is present in cis rather than trans. Amplification of the products of the cloned genes is observed when compared to haploid levels in some cases.

  16. Antibioresistance of Escherichia coli strains isolated from chicken colibacillosis in Western Algeria

    National Research Council Canada - National Science Library

    AGGAD, Hebib; HAMMOUDI, Abdelhamid

    2008-01-01

    ...%). However, only a low percentage of strains were resistant to enrofloxacine (6%) and colistine (3%). Although multiresistance was common, low association was found between the serotype and antibioresistance.

  17. An epidemiological study on the drug resistance of Escherichia coli strains isolated from women patients with urinary tract infection in Shalamzar, Iran

    Directory of Open Access Journals (Sweden)

    Gholamreza Farnoosh

    2015-03-01

    Full Text Available Objective: To investigate drug resistance of various strains of Escherichia coli (E. coli bacteria isolated from female patients with urinary tracts infections (UTIs in Shalamzar, Iran. Methods: This study was conducted from April 2011 to April 2012 on 150 female patients with positive urine culture and 105 CFU/mL colony count. The pattern of antibiotic sensitivity was recognized using antibiogram by the disc diffusion method. Results: The results revealed that the predominant bacterium was E. coli (90%, followed by Klebsiella pneumonia (3%. Trimethoprim-sulfamethoxazole is the initial medicine to treat UTIs (without complications which demonstrated relatively poor activity against E. coli (with 40% sensitivity, though alternative medicines such as nitrofurantoin (97% sensitivity and ciprofloxacin (91% sensitivity showed good activity against E. coli as well. Conclusions: The findings emphasized the necessity of pursuing the investigations in national and local governments in order to retain the efficacy of treating UTIs using effective antibiotics.

  18. 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...

  19. Metabolic engineering for the production of shikimic acid in an evolved Escherichia coli strain lacking the phosphoenolpyruvate: carbohydrate phosphotransferase system

    Directory of Open Access Journals (Sweden)

    Bolívar Francisco

    2010-04-01

    Full Text Available Abstract Background Shikimic acid (SA is utilized in the synthesis of oseltamivir-phosphate, an anti-influenza drug. In this work, metabolic engineering approaches were employed to produce SA in Escherichia coli strains derived from an evolved strain (PB12 lacking the phosphoenolpyruvate:carbohydrate phosphotransferase system (PTS- but with capacity to grow on glucose. Derivatives of PB12 strain were constructed to determine the effects of inactivating aroK, aroL, pykF or pykA and the expression of plasmid-coded genes aroGfbr, tktA, aroB and aroE, on SA synthesis. Results Batch cultures were performed to evaluate the effects of genetic modifications on growth, glucose consumption, and aromatic intermediate production. All derivatives showed a two-phase growth behavior with initial high specific growth rate (μ and specific glucose consumption rate (qs, but low level production of aromatic intermediates. During the second growth phase the μ decreased, whereas aromatic intermediate production reached its maximum. The double aroK- aroL- mutant expressing plasmid-coded genes (strain PB12.SA22 accumulated SA up to 7 g/L with a yield of SA on glucose of 0.29 mol/mol and a total aromatic compound yield (TACY of 0.38 mol/mol. Single inactivation of pykF or pykA was performed in PB12.SA22 strain. Inactivation of pykF caused a decrease in μ, qs, SA production, and yield; whereas TACY increased by 33% (0.5 mol/mol. Conclusions The effect of increased availability of carbon metabolites, their channeling into the synthesis of aromatic intermediates, and disruption of the SA pathway on SA production was studied. Inactivation of both aroK and aroL, and transformation with plasmid-coded genes resulted in the accumulation of SA up to 7 g/L with a yield on glucose of 0.29 mol/mol PB12.SA22, which represents the highest reported yield. The pykF and pykA genes were inactivated in strain PB12.SA22 to increase the production of aromatic compounds in the PTS

  20. Metabolic engineering for the production of shikimic acid in an evolved Escherichia coli strain lacking the phosphoenolpyruvate: carbohydrate phosphotransferase system.

    Science.gov (United States)

    Escalante, Adelfo; Calderón, Rocío; Valdivia, Araceli; de Anda, Ramón; Hernández, Georgina; Ramírez, Octavio T; Gosset, Guillermo; Bolívar, Francisco

    2010-04-12

    Shikimic acid (SA) is utilized in the synthesis of oseltamivir-phosphate, an anti-influenza drug. In this work, metabolic engineering approaches were employed to produce SA in Escherichia coli strains derived from an evolved strain (PB12) lacking the phosphoenolpyruvate:carbohydrate phosphotransferase system (PTS-) but with capacity to grow on glucose. Derivatives of PB12 strain were constructed to determine the effects of inactivating aroK, aroL, pykF or pykA and the expression of plasmid-coded genes aroGfbr, tktA, aroB and aroE, on SA synthesis. Batch cultures were performed to evaluate the effects of genetic modifications on growth, glucose consumption, and aromatic intermediate production. All derivatives showed a two-phase growth behavior with initial high specific growth rate (mu) and specific glucose consumption rate (qs), but low level production of aromatic intermediates. During the second growth phase the mu decreased, whereas aromatic intermediate production reached its maximum. The double aroK- aroL- mutant expressing plasmid-coded genes (strain PB12.SA22) accumulated SA up to 7 g/L with a yield of SA on glucose of 0.29 mol/mol and a total aromatic compound yield (TACY) of 0.38 mol/mol. Single inactivation of pykF or pykA was performed in PB12.SA22 strain. Inactivation of pykF caused a decrease in mu, qs, SA production, and yield; whereas TACY increased by 33% (0.5 mol/mol). The effect of increased availability of carbon metabolites, their channeling into the synthesis of aromatic intermediates, and disruption of the SA pathway on SA production was studied. Inactivation of both aroK and aroL, and transformation with plasmid-coded genes resulted in the accumulation of SA up to 7 g/L with a yield on glucose of 0.29 mol/mol PB12.SA22, which represents the highest reported yield. The pykF and pykA genes were inactivated in strain PB12.SA22 to increase the production of aromatic compounds in the PTS- background. Results indicate differential roles of Pyk

  1. Characteristics of Emerging Human-Pathogenic Escherichia coli O26:H11 Strains Isolated in France between 2010 and 2013 and Carrying the stx2d Gene Only

    Science.gov (United States)

    Delannoy, Sabine; Mariani-Kurkdjian, Patricia; Bonacorsi, Stephane; Liguori, Sandrine

    2014-01-01

    Strains of Escherichia coli O26:H11 that were positive for stx2 alone (n = 23), which were not epidemiologically related or part of an outbreak, were isolated from pediatric patients in France between 2010 and 2013. We were interested in comparing these strains with the new highly virulent stx2a-positive E. coli O26 clone sequence type 29 (ST29) that has emerged recently in Europe, and we tested them by multilocus sequence typing (MLST), stx2 subtyping, clustered regularly interspaced short palindromic repeat (CRISPR) sequencing, and plasmid (ehxA, katP, espP, and etpD) and chromosomal (Z2098, espK, and espV) virulence gene profiling. We showed that 16 of the 23 strains appeared to correspond to this new clone, but the characteristics of 12 strains differed significantly from the previously described characteristics, with negative results for both plasmid and chromosomal genetic markers. These 12 strains exhibited a ST29 genotype and related CRISPR arrays (CRISPR2a alleles 67 or 71), suggesting that they evolved in a common environment. This finding was corroborated by the presence of stx2d in 7 of the 12 ST29 strains. This is the first time that E. coli O26:H11 carrying stx2d has been isolated from humans. This is additional evidence of the continuing evolution of virulent Shiga toxin-producing E. coli (STEC) O26 strains. A new O26:H11 CRISPR PCR assay, SP_O26_E, has been developed for detection of these 12 particular ST29 strains of E. coli O26:H11. This test is useful to better characterize the stx2-positive O26:H11 clinical isolates, which are associated with severe clinical outcomes such as bloody diarrhea and hemolytic uremic syndrome. PMID:25428148

  2. The Adherent/Invasive Escherichia coli Strain LF82 Invades and Persists in Human Prostate Cell Line RWPE-1, Activating a Strong Inflammatory Response.

    Science.gov (United States)

    Conte, Maria P; Aleandri, Marta; Marazzato, Massimiliano; Conte, Antonietta L; Ambrosi, Cecilia; Nicoletti, Mauro; Zagaglia, Carlo; Gambara, Guido; Palombi, Fioretta; De Cesaris, Paola; Ziparo, Elio; Palamara, Anna T; Riccioli, Anna; Longhi, Catia

    2016-11-01

    Adherent/invasive Escherichia coli (AIEC) strains have recently been receiving increased attention because they are more prevalent and persistent in the intestine of Crohn's disease (CD) patients than in healthy subjects. Since AIEC strains show a high percentage of similarity to extraintestinal pathogenic E. coli (ExPEC), neonatal meningitis-associated E. coli (NMEC), and uropathogenic E. coli (UPEC) strains, here we compared AIEC strain LF82 with a UPEC isolate (strain EC73) to assess whether LF82 would be able to infect prostate cells as an extraintestinal target. The virulence phenotypes of both strains were determined by using the RWPE-1 prostate cell line. The results obtained indicated that LF82 and EC73 are able to adhere to, invade, and survive within prostate epithelial cells. Invasion was confirmed by immunofluorescence and electron microscopy. Moreover, cytochalasin D and colchicine strongly inhibited bacterial uptake of both strains, indicating the involvement of actin microfilaments and microtubules in host cell invasion. Moreover, both strains belong to phylogenetic group B2 and are strong biofilm producers. In silico analysis reveals that LF82 shares with UPEC strains several virulence factors: namely, type 1 pili, the group II capsule, the vacuolating autotransporter toxin, four iron uptake systems, and the pathogenic island (PAI). Furthermore, compared to EC73, LF82 induces in RWPE-1 cells a marked increase of phosphorylation of mitogen-activated protein kinases (MAPKs) and of NF-κB already by 5 min postinfection, thus inducing a strong inflammatory response. Our in vitro data support the hypothesis that AIEC strains might play a role in prostatitis, and, by exploiting host-cell signaling pathways controlling the innate immune response, likely facilitate bacterial multiplication and dissemination within the male genitourinary tract. Copyright © 2016 Conte et al.

  3. Comparative genomic analysis of two novel sporadic Shiga toxin-producing Escherichia coli O104:H4 strains isolated 2011 in Germany.

    Directory of Open Access Journals (Sweden)

    Erhard Tietze

    Full Text Available A large outbreak of gastrointestinal disease occurred in 2011 in Germany which resulted in almost 4000 patients with acute gastroenteritis or hemorrhagic colitis, 855 cases of a hemolytic uremic syndrome and 53 deaths. The pathogen was an uncommon, multiresistant Escherichia coli strain of serotype O104:H4 which expressed a Shiga toxin characteristic of enterohemorrhagic E. coli and in addition virulence factors common to enteroaggregative E. coli. During post-epidemic surveillance of Shiga toxin-producing E. coli (STEC all but two of O104:H4 isolates were indistinguishable from the epidemic strain. Here we describe two novel STEC O104:H4 strains isolated in close spatiotemporal proximity to the outbreak which show a virulence gene panel, a Shiga toxin-mediated cytotoxicity towards Vero cells and aggregative adherence to Hep-2 cells comparable to the outbreak strain. They differ however both from the epidemic strain and from each other, by their antibiotic resistance phenotypes and some other features as determined by routine epidemiological subtyping methods. Whole genome sequencing of these two strains, of ten outbreak strain isolates originating from different time points of the outbreak and of one historical sporadic EHEC O104:H4 isolate was performed. Sequence analysis revealed a clear phylogenetic distance between the two variant strains and the outbreak strain finally identifying them as epidemiologically unrelated isolates from sporadic cases. These findings add to the knowledge about this emerging pathogen, illustrating a certain diversity within the bacterial core genome as well as loss and gain of accessory elements. Our results do also support the view that distinct new variants of STEC O104:H4 repeatedly might originate from yet unknown reservoirs, rather than that there would be a continuous diversification of a single epidemic strain established and circulating in Germany after the large outbreak in 2011.

  4. Comparative genomic analysis of two novel sporadic Shiga toxin-producing Escherichia coli O104:H4 strains isolated 2011 in Germany.

    Science.gov (United States)

    Tietze, Erhard; Dabrowski, Piotr Wojciech; Prager, Rita; Radonic, Aleksandar; Fruth, Angelika; Auraß, Philipp; Nitsche, Andreas; Mielke, Martin; Flieger, Antje

    2015-01-01

    A large outbreak of gastrointestinal disease occurred in 2011 in Germany which resulted in almost 4000 patients with acute gastroenteritis or hemorrhagic colitis, 855 cases of a hemolytic uremic syndrome and 53 deaths. The pathogen was an uncommon, multiresistant Escherichia coli strain of serotype O104:H4 which expressed a Shiga toxin characteristic of enterohemorrhagic E. coli and in addition virulence factors common to enteroaggregative E. coli. During post-epidemic surveillance of Shiga toxin-producing E. coli (STEC) all but two of O104:H4 isolates were indistinguishable from the epidemic strain. Here we describe two novel STEC O104:H4 strains isolated in close spatiotemporal proximity to the outbreak which show a virulence gene panel, a Shiga toxin-mediated cytotoxicity towards Vero cells and aggregative adherence to Hep-2 cells comparable to the outbreak strain. They differ however both from the epidemic strain and from each other, by their antibiotic resistance phenotypes and some other features as determined by routine epidemiological subtyping methods. Whole genome sequencing of these two strains, of ten outbreak strain isolates originating from different time points of the outbreak and of one historical sporadic EHEC O104:H4 isolate was performed. Sequence analysis revealed a clear phylogenetic distance between the two variant strains and the outbreak strain finally identifying them as epidemiologically unrelated isolates from sporadic cases. These findings add to the knowledge about this emerging pathogen, illustrating a certain diversity within the bacterial core genome as well as loss and gain of accessory elements. Our results do also support the view that distinct new variants of STEC O104:H4 repeatedly might originate from yet unknown reservoirs, rather than that there would be a continuous diversification of a single epidemic strain established and circulating in Germany after the large outbreak in 2011.

  5. Activities of beta-lactam antibiotics against Escherichia coli strains producing extended-spectrum beta-lactamases.

    Science.gov (United States)

    Jacoby, G A; Carreras, I

    1990-01-01

    Seven extended-spectrum beta-lactamases related to TEM and four enzymes derived from SHV-1 were transferred to a common Escherichia coli host so that the activity of a variety of beta-lactams could be tested in a uniform genetic environment. For most derivatives, penicillinase activity was 10% or less than that of strains making TEM-1, TEM-2, or SHV-1 beta-lactamase, suggesting that reduced catalytic efficiency accompanied the broader substrate spectrum. Despite this deficit, resistance to aztreonam, carumonam, cefdinir, cefepime, cefixime, cefmenoxime, cefotaxime, cefotiam, cefpirome, cefpodoxime, ceftazidime, ceftibuten, ceftizoxime, ceftriaxone, cefuroxime, and E1040 was enhanced. For strains producing TEM-type enzymes, however, MICs of carumonam, cefepime, cefmenoxime, cefotiam, cefpirome, and ceftibuten were 8 micrograms/ml or less. Susceptibilities of cefmetazole, cefotetan, cefoxitin, flomoxef, imipenem, meropenem, moxalactam, temocillin, FCE 22101, and Sch 34343 were unaffected. FCE 22101, imipenem, meropenem, and Sch 34343 were inhibitory for all strains at 1 microgram/ml or less. In E. coli an OmpF- porin mutation in combination with an extended-spectrum beta-lactamase enhanced resistance to many of these agents, but generally by only fourfold. Hyperproduction of chromosomal AmpC beta-lactamase increased resistance to 7-alpha-methoxy beta-lactams but not that to temocillin. When tested at 8 micrograms/ml, clavulanate was more potent than sulbactam or tazobactam in overcoming resistance to ampicillin, while cefoperazone-sulbactam was more active than ticarcillin-clavulanate or piperacillin-tazobactam, especially against TEM-type extended-spectrum beta-lactamases. PMID:2193623

  6. Selection and characterization of a candidate therapeutic bacteriophage that lyses the Escherichia coli O104:H4 strain from the 2011 outbreak in Germany.

    Directory of Open Access Journals (Sweden)

    Maia Merabishvili

    Full Text Available In 2011, a novel strain of O104:H4 Escherichia coli caused a serious outbreak of foodborne hemolytic uremic syndrome and bloody diarrhea in Germany. Antibiotics were of questionable use and 54 deaths occurred. Candidate therapeutic bacteriophages that efficiently lyse the E. coli O104:H4 outbreak strain could be selected rather easily from a phage bank or isolated from the environment. It is argued that phage therapy should be more considered as a potential armament against the growing threat of (resistant bacterial infections.

  7. Pathotyping and antibiotic resistance of porcine enterovirulent Escherichia coli strains from Switzerland (2014-2015).

    Science.gov (United States)

    Brand, P; Gobeli, S; Perreten, V

    2017-07-01

    A total of 131 porcine E. coli were isolated in 2014 and 2015 from the gut of 115 pigs raised in Switzerland and suffering from diarrhea. The isolates were tested for antibiotic resistance, serotypes, virulence factors and genetic diversity. Serotypes were assigned by agglutination tests and virulence genes were identified by polymerase chain reaction (PCR). Antibiotic resistance profile was determined by the measurement of the MIC of 14 antibiotics and by the detection of the corresponding genes using microarray and PCR approaches. Genetic diversity was determined by repetitive palindromic PCR (rep- PCR) revealing a heterogenous population. Half of the E. coli isolates possessing virulence factors could not be assigned to any of the 19 serotypes tested, but contained toxins and adhesins similarly to the sero-typable E. coli isolates. The most prevalent E. coli serotypes found were K88ac (18%), O139:K82 (6%), O141:K85ac (5%), O108:K`V189` (5%), O119:K`V113` (3%) and O157:K`V17` (2%). The combination of toxins EAST-1, STb and LT-I and adhesin F4 characterizing ETEC was the most frequent. The shigatoxin Stx2e (STEC) and intimin Eae (EPEC) were also detected, but less frequently. Seventy percent of the isolates were resistant to at least one antibiotic and 29% were resistant to more than 3 antibiotics. Isolates exhibited resistance to tetracycline (50%) associated to resistance genes tet(A), tet(B) and tet(C), sulfamethoxazole (49%) [sul1, sul2 and sul3], trimethoprim (34%) [dfr], nalidixic acid (29%), ampicillin (26%) [blaTEM-1], gentamicin (17%) [aac(3) -IIc, aac(3) -IVa and aac(3) -VIa], chloramphenicol (17%) [catAI and catAIII], and ciprofloxacin (8%) [mutations in GyrA (S83L) and ParC (S80I)]. All isolates were susceptible to 3rd generation cephalosporins, carbapenems, colistin and tigecycline. Pathogenic E. coli isolates from pigs in Switzerland could frequently not be assigned to a known serotype even if they contained diarrhea-causing virulence factors. They

  8. GENE TRANSFER BY F' STRAINS OF ESCHERICHIA COLI K-12. II. INTERACTION BETWEEN F-MEROGENOTE AND CHROMOSOME DURING TRANSFER.

    Science.gov (United States)

    PITTARD, J; ADELBERG, E A

    1963-06-01

    Pittard, James (Yale University, New Haven, Conn.) and Edward A. Adelberg. Gene transfer by F' strains of Escherichia coli K-12. II. Interaction between F-merogenote and chromosome during transfer. J. Bacteriol. 85:1402-1408. 1963.-When F' strains harboring the F-merogenate F(14) are mated with female recipients, the transfer of the F-merogenote begins, in the majority of cases, before chromosome transfer. The markers on F(14) are transferred in the sequence met-1, arg-1, ilva-16, and sex-factor, met-1 being transferred first and sex-factor being transferred last, 9 min after met-1. In the class of zygotes that have received both the F-merogenote marker met-1 and the chromosomal marker xyl or mal, the gradient of recombination frequencies for the F-merogenote markers arg-1 and ilva-16 is much steeper than in the corresponding zygotes that have not received chromosomal markers. In F' strains which exhibit an increased frequency of transfer of chromosome markers, this gradient of recombination frequencies for merogenote markers is much steeper. An analysis of experiments involving an F' strain with a much shorter F-merogenote, F(16), and of a triparental mating in which F-merogenote and chromosome were transferred from different donor cells reveals that the effect of chromosome transfer on the recovery of distal F-merogenote markers in the zygotes is not due to any form of postzygotic elimination. It is suggested that, when F' strains which are transferring F-merogenote begin to transfer chromosome, the latter event causes breakage of the F-merogenote. A second consequence of this interaction is a delay of 8 to 10 min in the first appearance of chromosomal markers in the zygotes.

  9. Carriage of extended-spectrum beta-lactamase-plasmids does not reduce fitness but enhances virulence in some strains of pandemic E. coli lineages

    Directory of Open Access Journals (Sweden)

    Katharina eSchaufler

    2016-03-01

    Full Text Available Pathogenic ESBL-producing E. coli lineages occur frequently worldwide, not only in a human health context but in animals and the environment, also in settings with low antimicrobial pressures. This study investigated the fitness costs of ESBL-plasmids and their influence on chromosomally encoded features associated with virulence, such as those involved in the planktonic and sessile behaviors of ST131 and ST648 E. coli. ESBL-plasmid-carrying wild-type E. coli strains, their corresponding ESBL-plasmid-cured variants (PCV, and complementary ESBL-carrying transformants were comparatively analyzed using growth curves, Omnilog® phenotype microarray (PM assays, macrocolony and biofilm formation, swimming motility, and RNA sequence analysis. Growth curves and PM results pointed towards similar growth and metabolic behaviors among the strains. Phenotypic differences in some strains were detected, including enhanced curli fimbriae and/or cellulose production as well as a reduced swimming capacity of some ESBL-carrying strains, as compared to their respective PCVs. RNA sequencing mostly confirmed the phenotypic results, suggesting that the chromosomally encoded csgD pathway is a key factor involved. These results contradict the hypothesis that ESBL-plasmid-carriage leads to a fitness loss in ESBL-carrying strains. Instead, the results indicate an influence of some ESBL-plasmids on chromosomally encoded features associated with virulence in some E. coli strains. In conclusion, apart from antibiotic resistance selective advantages, ESBL-plasmid-carriage may also lead to enhanced virulence or adaption to specific habitats in some strains of pandemic ESBL-producing E. coli lineages.

  10. Diversity of Shiga Toxin-Producing Escherichia coli (STEC) O26:H11 Strains Examined via stx Subtypes and Insertion Sites of Stx and EspK Bacteriophages

    Science.gov (United States)

    Bonanno, Ludivine; Loukiadis, Estelle; Mariani-Kurkdjian, Patricia; Oswald, Eric; Garnier, Lucille; Michel, Valérie

    2015-01-01

    Shiga toxin-producing Escherichia coli (STEC) is a food-borne pathogen that may be responsible for severe human infections. Only a limited number of serotypes, including O26:H11, are involved in the majority of serious cases and outbreaks. The main virulence factors, Shiga toxins (Stx), are encoded by bacteriophages. Seventy-four STEC O26:H11 strains of various origins (including human, dairy, and cattle) were characterized for their stx subtypes and Stx phage chromosomal insertion sites. The majority of food and cattle strains possessed the stx1a subtype, while human strains carried mainly stx1a or stx2a. The wrbA and yehV genes were the main Stx phage insertion sites in STEC O26:H11, followed distantly by yecE and sbcB. Interestingly, the occurrence of Stx phages inserted in the yecE gene was low in dairy strains. In most of the 29 stx-negative E. coli O26:H11 strains also studied here, these bacterial insertion sites were vacant. Multilocus sequence typing of 20 stx-positive or stx-negative E. coli O26:H11 strains showed that they were distributed into two phylogenetic groups defined by sequence type 21 (ST21) and ST29. Finally, an EspK-carrying phage was found inserted in the ssrA gene in the majority of the STEC O26:H11 strains but in only a minority of the stx-negative E. coli O26:H11 strains. The differences in the stx subtypes and Stx phage insertion sites observed in STEC O26:H11 according to their origin might reflect that strains circulating in cattle and foods are clonally distinct from those isolated from human patients. PMID:25819955

  11. Creation of a Dense Transposon Insertion Library Using Bacterial Conjugation in Enterobacterial Strains Such As Escherichia Coli or Shigella flexneri.

    Science.gov (United States)

    Freed, Nikki E

    2017-09-23

    Transposon mutagenesis is a method that allows gene disruption via the random genomic insertion of a piece of DNA called a transposon. The protocol below outlines a method for high efficiency transfer between bacterial strains of a plasmid harboring a transposon containing a kanamycin resistance marker. The plasmid-borne transposase is encoded by a variant tnp gene that inserts the transposon into the genome of the recipient strain with very low insertional bias. This method thus allows the creation of large mutant libraries in which transposons have been inserted into unique genomic positions in a recipient strain of either Escherichia coli or Shigella flexneri bacteria. By using bacterial conjugation, as opposed to other methods such as electroporation or chemical transformation, large libraries with hundreds of thousands of unique clones can be created. This yields high-density insertion libraries, with insertions occurring as frequently as every 4-6 base pairs in non-essential genes. This method is superior to other methods as it allows for an inexpensive, easy to use, and high efficiency method for the creation of a dense transposon insertion library. The transposon library can be used in downstream applications such as transposon sequencing (Tn-Seq), to infer genetic interaction networks, or more simply, in mutational (forward genetic) screens.

  12. Community carriage of ESBL-producing Escherichia coli is associated with strains of low pathogenicity: a Swedish nationwide study.

    Science.gov (United States)

    Ny, Sofia; Löfmark, Sonja; Börjesson, Stefan; Englund, Stina; Ringman, Maj; Bergström, Jakob; Nauclér, Pontus; Giske, Christian G; Byfors, Sara

    2017-02-01

    Community carriage of ESBL-producing Escherichia coli (EPE) is common worldwide and there is a need to understand the connection between carriage and infection. We compared the molecular characteristics of EPE among Swedish community carriers with those of EPE causing invasive infections. We collected 2134 faecal samples from randomly selected Swedish inhabitants and examined them for the presence of EPE. All participating volunteers answered a questionnaire about putative risk factors for EPE carriage. Suspected EPE isolates (n = 418) from patients with bloodstream infection (BSI) were collected from Swedish laboratories. Isolates were genotypically and phenotypically characterized. Our results show that the EPE population found in carriers generally had lower pathogenicity compared with the isolates from BSIs, since carriers had a lower proportion of E. coli belonging to phylogroup B2, ST131 and ST131 subclone H30-Rx. Isolates from carriers also had lower levels of multiresistance. The Swedish carriage rate of EPE was 4.7% (101/2134) among healthy volunteers. Risk factors associated with carriage were travel to countries in Asia (OR = 3.6, 95% CI = 1.4-9.2) and Africa (OR = 3.6, 95% CI = 1.7-7.7) and a diet without pork (OR = 0.5, 95% CI = 0.3-0.8 for pork eaters). E. coli host factors previously associated with higher pathogenicity were all more common in BSIs compared with carriers. This indicates that the risk of invasive infection with EPE may be relatively modest in many community carriers and that EPE carriage of high-risk strains should be the focus of attention for prevention. © The Author 2016. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy.

  13. Apramycin treatment affects selection and spread of a multidrug-resistant Escherichia coli strain able to colonize the human gut in the intestinal microbiota of pigs

    DEFF Research Database (Denmark)

    Herrero-Fresno, Ana; Zachariasen, Camilla; Hansen, Monica Hegstad

    2016-01-01

    The effect of apramycin treatment on transfer and selection of an Escherichia coli strain (E. coli 912) in the intestine of pigs was analyzed through an in vivo experiment. The strain was sequenced and assigned to the sequence type ST101 and serotype O11. It carried resistance genes to apramycin/gentamicin...... of treatment, and apramycin treatment resulted in significantly higher counts compared to the non-treated group. This represents the first demonstration of how antimicrobial treatment affects spread of resistant bacteria in pig production. The use of apramycin may lead to enhanced spread of gentamicin-resistant......-treated (pen 3), along with a non-inoculated control group (pen 1). Two pigs of pen 2 and 3 were inoculated intragastrically with a rifampicin resistant variant of the strain. Apramycin treatment in pen 2 was initiated immediately after inoculation. Strain colonization was assessed in the feces from all pigs...

  14. RESEARCHES CONCERNING THE ANTIBIOTIC RESISTANCE OF ESCHERICHIA COLI STRAINS ISOLATED FROM URINARY TRACT INFECTIONS IN VÎLCEA POPULATION, BETWEEN 2010 - 2011

    Directory of Open Access Journals (Sweden)

    Ionica Deliu

    2013-12-01

    Full Text Available The antibiotic resistance of pathogenic or opportunistic bacteria play a very important role in medical world, being the main concern for future of therapeutic solution. The urinary tract infections are considered the most common infections. The most common causes of urinary tract infections are E. coli strains, from Enterobacteriaceae Family, but another bacterial species might be implicated. For these bacteria the phenomenon of antibiotic resistance increased continuously. In this paper we present the results of investigation about 1090 children and adult patients (Rm. Valcea city, during one year with symptoms of urinary tract infection, in MondoMedica Medical Laboratory. The samples were investigated by usual methods and bacterial agents were identified. The E. coli strains (43.54% of confirmed urinary infections were tested through antibiogram for their antibiotic resistance. For tested strains, the bacteria presented high resistance to Ampicillin and Trimethoprim+Sulphamethoxazole, both in children and adult patient. The sensitivity of bacterial strains was higher for Gentamicin.

  15. Characterization of enteropathogenic Escherichia coli (EPEC) strains isolated during the chicken slaughtering process

    OpenAIRE

    Alonso, Mónica Z.; Sanz, Marcelo E; Nora L Padola; Lucchesi, Paula M.A.

    2017-01-01

    En Argentina, Escherichia coli enteropatogénico (EPEC) es uno de los agentes más prevalentes aislados de niños con diarrea. Debido a que la contaminación con este patotipo en productos de pollo podría ocurrir durante el proceso de faena, nos planteamos como objetivo aislar y caracterizar EPEC de muestras de animales vivos (cloacas), carcasas evisceradas sin lavar, carcasas lavadas y agua del tanque de enfriamiento. Se caracterizaron 29 aislamientos de EPEC que presentaron una amplia variedad ...

  16. Prevalence of adhesive genes among uropathogenic Escherichia coli strains isolated from patients with urinary tract infection in Mangalore

    Directory of Open Access Journals (Sweden)

    A V Shetty

    2014-01-01

    Full Text Available The study was carried out to detect the adhesive genes pap (pyelonephritis associated pili, sfa (S fimbrial adhesin and afa (afimbrial adhesin from Escherichia coli strains isolated in patients diagnosed with urinary tract infection (UTI. A total of 23% of the isolates were positive for pap, sfa and afa genes with a prevalence of 60.87% (14/23, 39.1% (9/23 and 39.1% (9/23, respectively. Prevalence of multiple adhesive genes was 8.7% (2/23 for pap and afa, 30.43% (7/23 for pap and sfa. Significant numbers of isolates were positive for Congo red binding (80% and haemolysin production 60%. The prevalence of multiple adhesive genes indicate the potential to adhere and subsequently cause a systemic infection among UTI patients.

  17. Characterizing Strain Variation in Engineered E. coli Using a Multi-Omics-Based Workflow

    DEFF Research Database (Denmark)

    Brunk, Elizabeth; George, Kevin W.; Alonso-Gutierrez, Jorge

    2016-01-01

    to study the effects of introducing a heterologous pathway into a microbial host. This workflow incorporates complementary approaches from computational systems biology, metabolic engineering, and synthetic biology; provides molecular insight into how the host organism microenvironment changes due......Understanding the complex interactions that occur between heterologous and native biochemical pathways represents a major challenge in metabolic engineering and synthetic biology. We present a workflow that integrates metabolomics, proteomics, and genome-scale models of Escherichia coli metabolism....... Application of this workflow identified the roles of candidate genes, pathways, and biochemical reactions in observed experimental phenomena and facilitated the construction of a mutant strain with improved productivity. The contributed workflow is available as an open-source tool in the form of i...

  18. Strain engineering and process optimization for enhancing the production of a thermostable steryl glucosidase in Escherichia coli.

    Science.gov (United States)

    Eberhardt, Florencia; Aguirre, Andres; Menzella, Hugo G; Peiru, Salvador

    2017-01-01

    Biodiesels produced from transesterification of vegetable oils have a major problem in quality due to the presence of precipitates, which are mostly composed of steryl glucosides (SGs). We have recently described an enzymatic method for the efficient removal of SGs from biodiesel, based on the activity of a thermostable β-glycosidase from Thermococcus litoralis. In the present work, we describe the development of an Escherichia coli-based expression system and a high cell density fermentation process. Strain and process engineering include the assessment of different promoters to drive the expression of a codon-optimized gene, the co-expression of molecular chaperones and the development of a high cell density fermentation process. A 200-fold increase in the production titers was achieved, which directly impacts on the costs of the industrial process for treating biodiesel.

  19. Effects of pteridines on chloramine-T-induced growth inhibition in E. coli strains: correlations with molecular structure.

    Science.gov (United States)

    Horejsi, R; Estelberger, W; Mlekusch, W; Möller, R; Ottl, K; Vrecko, K; Reibnegger, G

    1996-01-01

    Little is known about the biological significance of most pteridines, despite their ubiquitous occurrence in living cells. Seventeen different pteridines were tested for their ability to modulate the growth inhibitory effect of the disinfectant chloramine-T on three different strains of Escherichia coli bacteria. We found striking differences between the pteridine derivatives: whereas aromatic pterins with a hydroxy function at side chain atom C2' increased the growth inhibition, those with a 7,8-dihydro structure exerted a suppressive effect. These results are in excellent agreement with previously observed effects of pteridine derivatives on chloramine-T-induced luminol-dependent chemiluminescence, and together, are highly suggestive of a general interaction of these compounds with oxygen or chlorine free radicals. This interaction is likely to have biological significance and might offer an explanation for the widespread occurrence of pteridines.

  20. Modeling the Endogenous Sunlight Inactivation Rates of Laboratory Strain and Wastewater E. coli and Enterococci Using Biological Weighting Functions.

    Science.gov (United States)

    Silverman, Andrea I; Nelson, Kara L

    2016-11-15

    Models that predict sunlight inactivation rates of bacteria are valuable tools for predicting the fate of pathogens in recreational waters and designing natural wastewater treatment systems to meet disinfection goals. We developed biological weighting function (BWF)-based numerical models to estimate the endogenous sunlight inactivation rates of E. coli and enterococci. BWF-based models allow the prediction of inactivation rates under a range of environmental conditions that shift the magnitude or spectral distribution of sunlight irradiance (e.g., different times, latitudes, water absorbances, depth). Separate models were developed for laboratory strain bacteria cultured in the laboratory and indigenous organisms concentrated directly from wastewater. Wastewater bacteria were found to be 5-7 times less susceptible to full-spectrum simulated sunlight than the laboratory bacteria, highlighting the importance of conducting experiments with bacteria sourced directly from wastewater. The inactivation rate models fit experimental data well and were successful in predicting the inactivation rates of wastewater E. coli and enterococci measured in clear marine water by researchers from a different laboratory. Additional research is recommended to develop strategies to account for the effects of elevated water pH on predicted inactivation rates.

  1. [Construction and pathogenic identification of aes-31 gene mutant of avian pathogenic Escherichia coli strain E058].

    Science.gov (United States)

    Huan, Haixia; Zhang, Ke; Chen, Xiang; Gao, Song; Liu, Xiufan

    2010-12-01

    To find the primary function of aes-31 fragment through construction of defined mutation of Avian Pathogenic Escherichia coli strain E058 and animal experiments. The fragment of aes-31 was generated by PCR and cloned into pGEM-T-easy vector. A resultant suicide vector containing the aes-31 fragment named pMEG375-aes-31 was constructed and transformed to a receptor strain SM10. Then recombinant strain SM10 was hybridized with E058 strain in solid state. Mutant derivatives of strain E058 were generated by homologous recombination and were named E058 (delta aes-31). The 50% lethal dose (LD50) of E058 and E058 (delta aes-31) in commercial day-old chickens experimentally inoculated via intratrachea were 10(4.3) CFU and 10(3.5) CFU, respectively. The same way was used to inoculate with 10(8) CFU to obtain the pathogenic ability of E058 and E058 (delta aes-31) in 35-days-old SPF chickens. In the chicken challenge model,the mutant was tested to determine the individual function for virulence and persistence in 2-week-old SPF chicks. The pathogenicity test for E058 strain and E058 (delta aes-31) strain showed that the mutant had a higher mortality (75%) to 35-day-old specific pathogen-free (SPF) chicks than that of E058 (62.5%). In the chicken challenge model,there was no obviously CFUs difference in blood and lung in chicks of E058 group and E058 (delta aes-31) group 6 hours after inoculation. After 24 hours there was obvious CFUs difference in heart, liver, spleen, lung and blood in chicks of E058 group and E058 (delta aes-31) group. After 48 hours, there was also obvious CFUs difference in heart, liver and spleen in chicks of E058 group and E058 (delta aes-31) group E058 (delta aes-31) had a trend of increasing virulence in chicks. Aes-31 might be associated with negative regulatory gene for E058 virulence and its actual function needed further study.

  2. in vitro effectiveness of commercial bacteriophage cocktails on diverse extended spectrum beta-lactamase (ESBL producing Escherichia coli strains

    Directory of Open Access Journals (Sweden)

    Aycan Gundogdu

    2016-11-01

    Full Text Available The objective of this study is to determine the in vitro susceptibility of Georgian bacteriophage cocktails on multi-drug resistant extended-spectrum β-lactamase producing Escherichia coli (ESBL-EC isolated from patients' blood and urine cultures. 615 E. coli isolates were included in this study. PhP-typing and phylogenetic grouping were used for the typing. Antimicrobial resistance profiles and ESBL production of all isolates were confirmed according to CLSI criteria. The activities of four bacteriophage cocktails (Enko-phage, SES-bacteriophage, Pyo-bacteriophage and Intesti-bacteriophage were determined against 142 ESBL- EC using in vitro spot tests. According to this, Enko-phage were active against 87.3% of the tested strains while that ratio was 81.7% for intesti-bacteriophage, 81.7% for Pyo-bacteriophage and 59.2% for SES-bacteriophage cocktails. Based on the contingency tests, the phage cocktails were observed to be statistically significantly (p<0.001 more effective on ESBL-EC strains belonging to phylogenetic groups D and B2. The employed phage cocktails were found to be affective against all tested resistant types. These results are promising especially for the infections that are caused by multi-drug resistant pathogens that are difficult to treat. As this is a preliminary step to the potential clinical trials to be designed for the country, in vitro confirmation of their success on a multi-drug-resistant ESBL-EC collection should be accepted as an initial action, which is encouraging to consider clinical trials of phage therapy especially in countries which are not introduce phage therapy.

  3. Pulsed-field gel electrophoresis typing of Eschericia coli strains from samples collected before and after pivmecillinam or placebo treatment of uncomplicated community-acquired urinary tract infection in women

    DEFF Research Database (Denmark)

    Ejrnæs, K; Sandvang, D; Lundgren, Bettina

    2006-01-01

    ). The finding that the majority of UTIs at follow-up are caused by the primary infecting E. coli strain supports the theory of a vaginal and rectal reservoir but could also support the recent discovery that E. coli strains are able to persist in the bladder epithelium despite appropriate antibiotic treatment...

  4. Pulsed-field gel electrophoresis typing of Escherichia coli strains from samples collected before and after pivmecillinam or placebo treatment of uncomplicated community-acquired urinary tract infection in women

    DEFF Research Database (Denmark)

    Ejrnaes, Karen; Sandvang, Dorthe; Lundgren, Bettina

    2006-01-01

    ). The finding that the majority of UTIs at follow-up are caused by the primary infecting E. coli strain supports the theory of a vaginal and rectal reservoir but could also support the recent discovery that E. coli strains are able to persist in the bladder epithelium despite appropriate antibiotic treatment...

  5. Biological and genetic characteristics of uropathogenic Escherichia coli strains Características biológicas e estrutura clonal em amostras uropatogênicas de Escherichia coli

    Directory of Open Access Journals (Sweden)

    Wanderley Dias da SILVEIRA

    2001-12-01

    Full Text Available The aim of the present study was to determine biological characteristics such as expression of fimbriae, Congo red binding, production of hemolysin and aerobactin, adhesion to HeLa and uroepithelial cells and invasion of HeLa cells by Escherichia coli isolates obtained from patients showing clinical signs of urinary tract infection (UTI. Also, the presence of genes (apa, afa, spa for fimbria expression and cytotoxic necrotizing factors (CNF1, CNF2 was assayed using specific primers in PCR. The data obtained were compared with the clonal relationships obtained by analysis of multilocus enzyme electrophoresis (MLEE, restriction fragment length polymorphism (RFLP of the rDNA (ribotyping and enterobacterial repetitive intergenic consensus-PCR (ERIC-PCR. All isolates but one presented a combination of at least two of the characteristics studied, a fact suggesting the presence of pathogenicity islands (PAIs. Diffuse adherence type to HeLa cells was observed to occur in most of the strains, but adhesion to uroepithelial cells seems to be a more reliable test to verify pathogenicity. Although four strains seemed to be able to invade HeLa cells when assayed by light microscopy, electron microscopy studies demonstrated that these strains were not invasive. MLEE, RFLP and ERIC-PCR were able to group the isolates differently into main clusters that were not correlated with the presence of pathogenic traits.O objetivo deste trabalho foi estudar características biológicas tais como a expressão de fímbrias e adesinas, capacidade de absorção do corante Vermelho Congo, produção de hemolisina e aerobactina, adesão e invasão a células HeLa e adesão a células do epitélio urinário em amostras de Eschericia coli isoladas de pacientes com sinais clínicos de infecção do trato urinário (UTI. A presença dos genes responsáveis pela expressão de fímbrias (apa, afa e spa e das Citotoxinas Necrotizantes CNF1, CNF2 foi avaliada por PCR. Esses dados

  6. Identification and characterization of the first Escherichia coli strain carrying NDM-1 gene in China.

    Science.gov (United States)

    Liu, Zhiyuan; Li, Wei; Wang, Jie; Pan, Jian; Sun, Shipeng; Yu, Yanhua; Zhao, Bing; Ma, Yuzhi; Zhang, Tingju; Qi, Jie; Liu, Guijian; Lu, Fengmin

    2013-01-01

    New Delhi metallo-β-lactamase-1 (NDM-1), an acquired class B carbapenemase, is a significant clinical threat due to its extended hydrolysis of β-lactams including carbapenems. In this study, we identified the first confirmed clinical isolate of Escherichia coli BJ01 harboring bla(NDM-1) in China. The isolate is highly resistant to all tested antimicrobials except polymyxin. bla(NDM-1), bla(CTX-M-57), and bla TEM-1 were identified in the isolate. bla(NDM-1) was transferable to E. coli EC600 and DH5α in both plasmid conjugation experiments and plasmid transformation tests. BJ01 was identified as a new sequence type, ST224, by multilocus sequence typing. Analysis of genetic environment shows complex transposon-like structures surrounding the bla NDM-1 gene. Genetic analysis revealed that the region flanking bla(NDM-1) was very similar to previously identified NDM-positive Acinetobacter spp. isolated in China. The findings of this study raise attention to the emergence and spread of NDM-1-carrying Enterobacteriaceae in China.

  7. Identification and characterization of the first Escherichia coli strain carrying NDM-1 gene in China.

    Directory of Open Access Journals (Sweden)

    Zhiyuan Liu

    Full Text Available New Delhi metallo-β-lactamase-1 (NDM-1, an acquired class B carbapenemase, is a significant clinical threat due to its extended hydrolysis of β-lactams including carbapenems. In this study, we identified the first confirmed clinical isolate of Escherichia coli BJ01 harboring bla(NDM-1 in China. The isolate is highly resistant to all tested antimicrobials except polymyxin. bla(NDM-1, bla(CTX-M-57, and bla TEM-1 were identified in the isolate. bla(NDM-1 was transferable to E. coli EC600 and DH5α in both plasmid conjugation experiments and plasmid transformation tests. BJ01 was identified as a new sequence type, ST224, by multilocus sequence typing. Analysis of genetic environment shows complex transposon-like structures surrounding the bla NDM-1 gene. Genetic analysis revealed that the region flanking bla(NDM-1 was very similar to previously identified NDM-positive Acinetobacter spp. isolated in China. The findings of this study raise attention to the emergence and spread of NDM-1-carrying Enterobacteriaceae in China.

  8. Comparative proteomics of an extended spectrum β-lactamase producing Escherichia coli strain from the Iberian wolf.

    Science.gov (United States)

    Gonçalves, A; Poeta, P; Monteiro, R; Marinho, C; Silva, N; Guerra, A; Petrucci-Fonseca, F; Rodrigues, J; Torres, C; Vitorino, R; Domingues, P; Igrejas, G

    2014-06-02

    The Iberian wolf (Canis lupus signatus) is an endangered species native to the Iberian Peninsula. Due to their predatory and wild nature, these wolves serve as important indicators of environmental contamination by antimicrobial-resistant bacteria. β-Lactam antibiotics like cefotaxime are the most commonly used antibacterial agents. Bacterial resistance to these antibiotics occurs predominantly through enzymatic inactivation by extended-spectrum beta-lactamases. Escherichia coli strain WA57, isolated from Iberian wolf feces, is a cefotaxime-resistant strain that produces extended-spectrum beta-lactamases. In this study, using 2D-GE combined with MS and bioinformatics, we report significant differences in the abundance of 40 protein spots (p<0.01) from the extracellular, periplasmic, cytoplasmic, and membrane sub-proteomes and the whole-cell proteome of WA57 exposed and non-exposed to cefotaxime. A total of 315 protein spots were collected for protein identification. The comparative proteomics presented gives an overview of the complex changes in expression and metabolism that occur when WA57 is stressed with cefotaxime. Abundance of chaperone, porin and export proteins is particularly affected showing that the stress response and transport functions might directly influence the antibiotic resistance of this strain. This study highlights the importance of proteomics in detecting protein expression changes in bacterial strains exposed to stress such as that caused by cefotaxime. This approach might help us understand which pathways form barriers for antibiotics. This article is part of a Special Issue entitled: Environmental and structural proteomics. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Antibiotic resistance in Escherichia coli strains isolated from Antarctic bird feces, water from inside a wastewater treatment plant, and seawater samples collected in the Antarctic Treaty area

    Science.gov (United States)

    Rabbia, Virginia; Bello-Toledo, Helia; Jiménez, Sebastián; Quezada, Mario; Domínguez, Mariana; Vergara, Luis; Gómez-Fuentes, Claudio; Calisto-Ulloa, Nancy; González-Acuña, Daniel; López, Juana; González-Rocha, Gerardo

    2016-06-01

    Antibiotic resistance is a problem of global concern and is frequently associated with human activity. Studying antibiotic resistance in bacteria isolated from pristine environments, such as Antarctica, extends our understanding of these fragile ecosystems. Escherichia coli strains, important fecal indicator bacteria, were isolated on the Fildes Peninsula (which has the strongest human influence in Antarctica), from seawater, bird droppings, and water samples from inside a local wastewater treatment plant. The strains were subjected to molecular typing with pulsed-field gel electrophoresis to determine their genetic relationships, and tested for antibiotic susceptibility with disk diffusion tests for several antibiotic families: β-lactams, quinolones, aminoglycosides, tetracyclines, phenicols, and trimethoprim-sulfonamide. The highest E. coli count in seawater samples was 2400 cfu/100 mL. Only strains isolated from seawater and the wastewater treatment plant showed any genetic relatedness between groups. Strains of both these groups were resistant to β-lactams, aminoglycosides, tetracycline, and trimethoprim-sulfonamide.In contrast, strains from bird feces were susceptible to all the antibiotics tested. We conclude that naturally occurring antibiotic resistance in E. coli strains isolated from Antarctic bird feces is rare and the bacterial antibiotic resistance found in seawater is probably associated with discharged treated wastewater originating from Fildes Peninsula treatment plants.

  10. Fatores de virulência presentes em amostras de Escherichia coli uropatogênicas - UPEC para suínos Virulence factors of uropathogenic Escherichia coli - UPEC strains for pigs

    Directory of Open Access Journals (Sweden)

    Benito Guimarães de Brito

    2004-04-01

    Full Text Available As infecções urinárias são freqüentes nos rebanhos suínos, sendo a principal causa de descarte e mortalidade de animais adultos. Apesar das características multifatoriais da doença o microrganismo freqüentemente isolado é a Escherichia coli. Vários fatores de virulência de Escherichia coli foram descritos em amostras uropatogênicas e permitem diferenciar cepas patogênicas de não patogênicas. Esta revisão tem por objetivo apresentar alguns tópicos relativos aos fatores de virulência presentes em amostras de E. coli uropatogênicas para suínos.Urinary tract infections occur frequently in pig herds urinary infection is the most significant cause of culling and mortality of adult animals. Despite the multifactorial nature of this condition, Escherichia coli is frequently isolated from diseased animals. Several virulence factors were described on uropathogenic strains and they can be used to distinguish isolates. The objective of the present review is to present some topics related to virulence factors present in swine uropathogenic E. coli strains.

  11. Genomic distribution of the small multidrug resistance protein EmrE over 29 Escherichia coli strains reveals two forms of the protein

    NARCIS (Netherlands)

    Kolbusz, Magdalena A.; Slotboom, Dirk J.; Lolkema, Juke S.

    Analysis of the genomes of 29 Escherichia coli strains revealed two different versions of the EmrE protein, a member of the small multidrug resistance family. The versions are different in length and contain 110 residues (EMRE110) and 165 residues (EMRE165). The N-terminal extension found in the

  12. Stx1 prophage excision in Escherichia coli strain PA20 confers strong curli and biofilm formation by restoring native mlrA

    Science.gov (United States)

    Prophage insertions in Escherichia coli O157:H7 mlrA contribute to the low expression of curli fimbriae and biofilm observed in many clinical isolates. Varying levels of CsgD-dependent curli/biofilm expression are restored to strains bearing prophage insertions in mlrA by mutation of regulatory gene...

  13. Preliminary Remarks Regarding the Prevalence of ESBL-Producing Strains of E. coli and K. Pneumoniae, Isolated from Cows with Clinical Endometritis

    Directory of Open Access Journals (Sweden)

    Cristina Ioana CRIVEI

    2017-05-01

    In this preliminary study, by phenotypic methods was confirmed a prevalence of 35.3% for the ESBL strains of E. coli and K. pneumoniae, which requires further research to confirm by molecular biology the identification of ESBL resistance genes, but also for the plasmids encoding these gene transmission.

  14. Draft genome sequences of Escherichia coli O113:H21 strains recovered from a major produce-production region in California

    Science.gov (United States)

    Shiga toxin-producing Escherichia coli is a foodborne and waterborne pathogen and is responsible for outbreaks of human gastroenteritis. This report documents the draft genome sequences of seven O113:H21 strains recovered from livestock, wildlife, and soil samples collected in a major agricultural r...

  15. Emergence of a multiresistant KPC-3 and VIM-1 carbapenemase-producing Escherichia coli strain in Spain.

    Science.gov (United States)

    Porres-Osante, Nerea; Azcona-Gutiérrez, Jose Manuel; Rojo-Bezares, Beatriz; Undabeitia, Esther; Torres, Carmen; Sáenz, Yolanda

    2014-07-01

    To characterize the mechanisms involved in carbapenem resistance, as well as the genetic elements supporting their mobilization, in a multidrug-resistant Escherichia coli isolate. The E. coli isolate was obtained from a patient with fatal urinary sepsis. Antimicrobial susceptibility testing was performed by the disc diffusion and agar dilution methods. The E. coli molecular type and phylogroup were determined using multilocus sequence typing and the triple PCR technique, respectively. PCR and sequencing were used for virulence and resistance genotype characterization. Plasmid content and gene location were analysed by S1-PFGE, I-Ceu1-PFGE and hybridization experiments. Transformation assays were performed. The E. coli strain, typed as ST448 and phylogroup B1, was resistant to all tested antibiotics except fosfomycin, tigecycline and tetracycline. The following resistance and virulence genetic structures were obtained: ISKpn7 + bla(KPC-3) + ISKpn6 linked to Tn4401; tnpR + aac(6')-Ib'-9 + aadA1 + bla(OXA-9) + tnpR + bla(TEM-1a) + tnpB + strB + strA + sul2; intI1 + bla(VIM-1) + aac(6')-Ib' + aphA15 + aadA1 + catB2 + qacEΔ1-sul1 + orf5; ISEcp1 + bla(CMY-2); IS26 + bla(SHV-12); aph(3')-I; aac(3)-IV; floR; catA; and fimA. Mutations in the ampC promoter (-18, -1 and +58) and substitutions in the GyrA (Ser-83→Leu and Asp-87→Asn) and ParC (Ser-80→Ile) proteins were observed. IncFII (ST2), IncA/C and ColE(TP) plasmids of 145.5, 87 and 300 kb, and the bla(KPC-3) gene in the 145.5 kb IncFII plasmid. Transformant strains carried the IncFII and ColE(TP) plasmids, and the bla(KPC-3), bla(TEM-1a), bla(OXA-9), aadA1, aac(6')-Ib'-9, aac(3)-IV and floR genes. This is the first report of the co-production of KPC-3, VIM-1, SHV-12, OXA-9 and CMY-2 in a unique clinical multiresistant E. coli isolate. The dissemination of these genes on mobile genetic elements is alarming and complicates antimicrobial

  16. Genetic heterogeneity of Escherichia coli strains isolated from raw milk, Minas Frescal cheese, and food handlers Heterogeneidade genética de cepas de Escherichia coli isoladas de leite cru, queijo Minas Frescal e manipuladores

    Directory of Open Access Journals (Sweden)

    M.R.H. Campos

    2009-10-01

    Full Text Available From February 2004 to March 2005, 140 samples of food handlers - hands and nostrils - (92, raw milk (24, and minas frescal cheese (24 were analyzed for the presence of Escherichia coli in a dairy processing plant of Goiás State. Forty-seven E. coli strains were obtained and compared by DNA macrorestriction patterns obtained from pulsed-field gel electrophoresis following XbaI restriction in order to investigate the possible sources of cheese contaminations. Based on PFGE genotyping, one strain isolated from food the hands of a handler and five strains isolated from raw milk were identical or closely related to six strains from cheese suggesting, in these cases, the probable source of E. coli contamination in cheeses. No strain isolated from the nostrils was related to those found in cheeses or milk strains. The results showed high diversity among the strains, demonstrating a lack of predominance of an endemic clone in the dairy plant. This paper highlights the usefulness of PFGE as an epidemiological tool for determining the source of E. coli contamination in the food industry.Durante um ano, de fevereiro de 2004 a março de 2005, 140 amostras retiradas das mãos e das narinas de manipuladores de alimentos (92, do leite cru (24 e do queijo-de-minas frescal (24 foram analisadas para a presença de Escherichia coli, em um laticínio do Estado de Goiás. As 47 cepas obtidas foram comparadas por macrorrestrição do DNA com enzima XbaI, seguida de eletroforese em gel em campo pulsado (PFGE, a fim de investigar as possíveis fontes de contaminação do queijo. Baseado na genotipagem pelo PFGE, uma cepa obtida do leite cru e cinco cepas obtidas dos manipuladores mostraram similaridade maior que 80% com seis cepas isoladas do queijo, denotando forte correlação genética entre elas e sugerindo, nestes casos, a fonte provável de contaminação do produto final. Nenhuma cepa isolada do nariz foi relacionada às isoladas do queijo ou do leite. Os

  17. Escherichia coli Infections.

    Science.gov (United States)

    Makvana, Sejal; Krilov, Leonard R

    2015-04-01

    Virulent strains of Escherichia coli are responsible for most diarrheal infections, meningitis, septicemia, and urinary tract infections in children worldwide. Clinicians must learn to recognize, treat, and prevent these infections. After completing this article, readers should be able to: 1. Describe the epidemiology of E coli infections. 2. Recognize the clinical features of E coli infections, including the O157: H7 strain. 3. Appropriately treat children with various types of E coli infections. 4. Understand ways to prevent E coli infections.

  18. Strain differences in fitness of Escherichia coli O157:H7 to resist protozoan predation and survival in soil.

    Directory of Open Access Journals (Sweden)

    Subbarao V Ravva

    Full Text Available Escherichia coli O157:H7 (EcO157 associated with the 2006 spinach outbreak appears to have persisted as the organism was isolated, three months after the outbreak, from environmental samples in the produce production areas of the central coast of California. Survival in harsh environments may be linked to the inherent fitness characteristics of EcO157. This study evaluated the comparative fitness of outbreak-related clinical and environmental strains to resist protozoan predation and survive in soil from a spinach field in the general vicinity of isolation of strains genetically indistinguishable from the 2006 outbreak strains. Environmental strains from soil and feral pig feces survived longer (11 to 35 days for 90% decreases, D-value with Vorticella microstoma and Colpoda aspera, isolated previously from dairy wastewater; these D-values correlated (P<0.05 negatively with protozoan growth. Similarly, strains from cow feces, feral pig feces, and bagged spinach survived significantly longer in soil compared to clinical isolates indistinguishable by 11-loci multi-locus variable-number tandem-repeat analysis. The curli-positive (C+ phenotype, a fitness trait linked with attachment in ruminant and human gut, decreased after exposure to protozoa, and in soils only C- cells remained after 7 days. The C+ phenotype correlated negatively with D-values of EcO157 exposed to soil (rs = -0.683; P = 0.036, Vorticella (rs = -0.465; P = 0.05 or Colpoda (rs = -0.750; P = 0.0001. In contrast, protozoan growth correlated positively with C+ phenotype (Vorticella, rs = 0.730, P = 0.0004; Colpoda, rs = 0.625, P = 0.006 suggesting a preference for consumption of C+ cells, although they grew on C- strains also. We speculate that the C- phenotype is a selective trait for survival and possibly transport of the pathogen in soil and water environments.

  19. Detection of pathogenic strains by multiplex PCR and antimicrobial sensitivity of Escherichia coli isolated from piglets

    OpenAIRE

    Macêdo, N.R.; Menezes,C.P.L.; Lage, A.P.; Ristow,L.E.; Reis, A.; Guedes,R.M.C.

    2007-01-01

    Avaliou-se a freqüência dos genes de fímbrias (K88, K99, 987P, F18 e F41) e toxinas (LT, Stb, StaP e Stx2e) de cepas de E. coli isoladas de leitões com diarréia usando a técnica de PCR multiplex com primers específicos para esses genes, e estudou-se o padrão de sensibilidade das cepas patogênicas pelo método de difusão em disco ao florfenicol, ceftiofur sódico, colistina, fosfomicina, neomicina, norfloxacina, sulfa + trimetoprim, doxiciclina, tetraciclina e lincomicina. Foram utilizadas 144 a...

  20. Antibioresistance of Escherichia coli strains isolated in Morocco from chickens with colibacillosis.

    Science.gov (United States)

    Amara, A; Ziani, Z; Bouzoubaa, K

    1995-03-01

    Two hundred and fifty eight isolates of Escherichia coli were made from autopsied chickens showing lesions of avian colibacillosis. Antibiograms showed high levels of resistance (greater than 40%) to sulphonamides (SSS), oxytetracycline (OT), trimethoprim + sulphamethoxazole (STX) and chloramphenicol (C). Medium frequencies of resistances (from 15 to 40%) were noted for streptomycin (S), spectinomycin (SPT), nalidixic acid (NA), oxolinic acid (OA), flumequine (UB) and enrofloxacine (ENR). For ampicillin (AM), gentamicin (GM), nitrofurans (FT), colistin (CS) and rifampin (RA) the frequencies of resistance were low (less than 15%). A linked resistance was observed for the 4 quinolones. A significant percentage of isolates (82.5%) were resistant to at least 2 antimicrobial agents. The most frequent antibiotypes were: C.OT.SSS.STX (4.65%), C.OT.SSS.STX.OA.NA.UB.ENR (4.65%), AM.S.C.OT.SSS.STX (4.26%) and OT.SSS.STX (3.87%).

  1. Artificial biosynthesis of phenylpropanoic acids in a tyrosine overproducing Escherichia coli strain

    Directory of Open Access Journals (Sweden)

    Kang Sun-Young

    2012-12-01

    Full Text Available Abstract Background The phenylpropanoid metabolites are an extremely diverse group of natural products biosynthesized by plants, fungi, and bacteria. Although these compounds are widely used in human health care and nutrition services, their availability is limited by regional variations, and isolation of single compounds from plants is often difficult. Recent advances in synthetic biology and metabolic engineering have enabled artificial production of plant secondary metabolites in microorganisms. Results We develop an Escherichia coli system containing an artificial biosynthetic pathway that yields phenylpropanoic acids, such as 4-coumaric acid, caffeic acid, and ferulic acid, from simple carbon sources. These artificial biosynthetic pathways contained a codon-optimized tal gene that improved the productivity of 4-coumaric acid and ferulic acid, but not caffeic acid in a minimal salt medium. These heterologous pathways extended in E. coli that had biosynthesis machinery overproducing tyrosine. Finally, the titers of 4-coumaric acid, caffeic acid, and ferulic acid reached 974 mg/L, 150 mg/L, and 196 mg/L, respectively, in shake flasks after 36-hour cultivation. Conclusions We achieved one gram per liter scale production of 4-coumaric acid. In addition, maximum titers of 150 mg/L of caffeic acid and 196 mg/L of ferulic acid were achieved. Phenylpropanoic acids, such as 4-coumaric acid, caffeic acid, and ferulic acid, have a great potential for pharmaceutical applications and food ingredients. This work forms a basis for further improvement in production and opens the possibility of microbial synthesis of more complex plant secondary metabolites derived from phenylpropanoic acids.

  2. Response surface methodology for process parameter optimization of hydrogen yield by the metabolically engineered strain Escherichia coli DJT135.

    Science.gov (United States)

    Ghosh, Dipankar; Hallenbeck, Patrick C

    2010-03-01

    Metabolically engineered microbial strains can be usefully employed to give higher yields, but this also requires development of a suitable bioprocess. Maximization of product yield during fermentation requires that a number of process parameters, some of which may interact, be optimized. Here we report the effects of different fermentative process conditions; pH, temperature and glucose concentration, on the molar hydrogen yield by a genetically optimized Escherichia coli strain, DJT135. In order to simultaneously reduce the number of the experiments, and to obtain the interactions between the variables important for achieving maximum hydrogen production, a 3(K) full factorial Box-Behnken design and response surface methodology (RSM) were employed for experimental design and analysis. A maximum molar hydrogen yield of 1.69 mol H(2)mol(-1) glucose was obtained under the optimal conditions of 75 mM glucose, 35 degrees C and pH 6.5. Thus, RSM with Box-Behnken design is a useful method for achieving higher molar hydrogen yields by metabolically engineered organisms. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

  3. Genetically similar strains of Escherichia coli O157:H7 isolated from sheep, cattle and human patients

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    Söderlund Robert

    2012-10-01

    Full Text Available Abstract Background Comparatively little is known about the prevalence or the molecular characteristics of the zoonotic pathogen E. coli O157:H7 in the sheep reservoir. To investigate this and determine the host specificity of subclones of the bacterium, we have conducted a slaughterhouse prevalence study in sheep and compared the collected isolates to O157:H7 previously isolated from cattle and human patients. Results Verotoxin-producing O157:H7 was found in 11/597 (1.8% of samples from sheep in Swedish slaughterhouses, 9/492 faecal (1.8% and 2/105 ear samples (1.9%. All positive sheep were eaeA, hlyA, cdtV-B, vtx1, and partial sequencing of vtx2. The observed profiles were similar to those of cattle strains investigated previously. Conclusions The same pathogenic subtypes of VTEC O157:H7, including the highly virulent clade 8, appear to be present in both sheep and cattle in Sweden, suggesting strains can circulate freely between ruminant reservoirs.

  4. Carriage of stx2a differentiates clinical and bovine-biased strains of Escherichia coli O157.

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    Smriti Shringi

    Full Text Available Shiga toxin (Stx are cardinal virulence factors of enterohemorrhagic E. coli O157:H7 (EHEC O157. The gene content and genomic insertion sites of Stx-associated bacteriophages differentiate clinical genotypes of EHEC O157 (CG, typical of clinical isolates from bovine-biased genotypes (BBG, rarely identified among clinical isolates. This project was designed to identify bacteriophage-mediated differences that may affect the virulence of CG and BBG.Stx-associated bacteriophage differences were identified by whole genome optical scans and characterized among >400 EHEC O157 clinical and cattle isolates by PCR.Optical restriction maps of BBG strains consistently differed from those of CG strains only in the chromosomal insertion sites of Stx2-associated bacteriophages. Multiplex PCRs (stx1, stx2a, and stx2c as well as Stx-associated bacteriophage-chromosomal insertion site junctions revealed four CG and three BBG that accounted for >90% of isolates. All BBG contained stx2c and Stx2c-associated bacteriophage-sbcB junctions. All CG contained stx2a and Stx2a-associated bacteriophage junctions in wrbA or argW.Presence or absence of stx2a (or another product encoded by the Stx2a-associated bacteriophage is a parsimonious explanation for differential virulence of BBG and CG, as reflected in the distributions of these genotypes in humans and in the cattle reservoir.

  5. Discrimination of Enterohemorrhagic Escherichia coli (EHEC) from Non-EHEC Strains Based on Detection of Various Combinations of Type III Effector Genes

    Science.gov (United States)

    Delannoy, Sabine; Beutin, Lothar

    2013-01-01

    Enterohemorrhagic Escherichia coli (EHEC) strains comprise a subgroup of Shiga-toxin (Stx)-producing E. coli (STEC) and are characterized by a few serotypes. Among these, seven priority STEC serotypes (O26:H11, O45:H2, O103:H2, O111:H8, O121:H19, O145:H28, and O157:H7) are most frequently implicated in severe clinical illness worldwide. Currently, standard methods using stx, eae, and O-serogroup-specific gene sequences for detecting the top 7 EHEC serotypes bear the disadvantage that these genes can be found in non-EHEC strains as well. Here, we explored the suitability of ureD, espV, espK, espN, Z2098, and espM1 genes and combinations thereof as candidates for a more targeted EHEC screening assay. For a very large panel of E. coli strains (n = 1,100), which comprised EHEC (n = 340), enteropathogenic E. coli (EPEC) (n = 392), STEC (n = 193), and apathogenic strains (n = 175), we showed that these genetic markers were more prevalent in EHEC (67.1% to 92.4%) than in EPEC (13.3% to 45.2%), STEC (0.5% to 3.6%), and apathogenic E. coli strains (0 to 2.9%). It is noteworthy that 38.5% of the EPEC strains that tested positive for at least one of these genetic markers belonged to the top 7 EHEC serotypes, suggesting that such isolates might be Stx-negative derivatives of EHEC. The associations of espK with either espV, ureD, or Z2098 were the best combinations for more specific and sensitive detection of the top 7 EHEC strains, allowing detection of 99.3% to 100% of these strains. In addition, detection of 93.7% of the EHEC strains belonging to other serotypes than the top 7 offers a possibility for identifying new emerging EHEC strains. PMID:23884997

  6. Prevalence of adhesin and toxin genes in E. coli strains isolated from diarrheic and non-diarrheic pigs from smallholder herds in northern and eastern Uganda.

    Science.gov (United States)

    Ikwap, Kokas; Larsson, Jenny; Jacobson, Magdalena; Owiny, David Okello; Nasinyama, George William; Nabukenya, Immaculate; Mattsson, Sigbrit; Aspan, Anna; Erume, Joseph

    2016-08-05

    Enterotoxigenic E. coli (ETEC) significantly contribute to diarrhea in piglets and weaners. The smallholder pig producers in Uganda identified diarrhea as one of the major problems especially in piglets. The aim of this study was to; i) characterize the virulence factors of E. coli strains isolated from diarrheic and non-diarrheic suckling piglets and weaners from smallholder herds in northern and eastern Uganda and ii) identify and describe the post-mortem picture of ETEC infection in severely diarrheic piglets. Rectal swab samples were collected from 83 piglets and weaners in 20 herds and isolated E. coli were characterized by PCR, serotyping and hemolysis. The E. coli strains carried genes for the heat stable toxins STa, STb and EAST1 and adhesins F4 and AIDA-I. The genes for the heat labile toxin LT and adhesins F5, F6, F18 and F41 were not detected in any of the E. coli isolates. Where the serogroup could be identified, E. coli isolates from the same diarrheic pig belonged to the same serogroup. The prevalence of EAST1, STb, Stx2e, STa, AIDA-I, and F4 in the E. coli isolates from suckling piglets and weaners (diarrheic and non-diarrheic combined) was 29, 26.5, 2.4, 1.2, 16, and 8.4 %, respectively. However the prevalence of F4 and AIDA-I in E. coli from diarrheic suckling piglets alone was 22.2 and 20 %, respectively. There was no significant difference in the prevalence of the individual virulence factors in E. coli from the diarrheic and non-diarrheic pigs (p > 0.05). The main ETEC strains isolated from diarrheic and non-diarrheic pigs included F4/STb/EAST1 (7.2 %), F4/STb (1.2 %), AIDA/STb/EAST1 (8 %) and AIDA/STb (8 %). At post-mortem, two diarrheic suckling piglets carrying ETEC showed intact intestinal villi, enterocytes and brush border but with a layer of cells attached to the brush border, suggestive of ETEC infections. This study has shown that the F4 fimbriae is the most predominant in E. coli from diarrheic piglets in the study area and

  7. Construction of Escherichia coli Strains for Conversion of Nitroacetophenones to ortho-Aminophenols

    OpenAIRE

    Kadiyala, Venkateswarlu; Nadeau, Lloyd J.; Spain, Jim C.

    2003-01-01

    The predominant bacterial pathway for nitrobenzene (NB) degradation uses an NB nitroreductase and hydroxylaminobenzene (HAB) mutase to form the ring-fission substrate ortho-aminophenol. We tested the hypothesis that constructed strains might accumulate the aminophenols from nitroacetophenones and other nitroaromatic compounds. We constructed a recombinant plasmid carrying NB nitroreductase (nbzA) and HAB mutase A (habA) genes, both from Pseudomonas pseudoalcaligenes JS45, and expressed the en...

  8. Molecular cloning of Clostridium septicum vaccine strain alpha toxin gene in E. coli

    OpenAIRE

    Bozorgkhoo; Pilehchian Langroudi; Khaki; Jabbari; Moradi Bidhendi; Moosawi Shoshtari

    2014-01-01

    Clostridium septicum a Gram positive anaerobic bacterium produces several toxins including alpha, beta, gamma and delta. C. septicum alpha toxin is lethal and is responsible for a serious disease known as gas gangrene. The aim of the present study was to molecular cloning and sequencing of C. septicum vaccine strain alpha toxin gene. Genomic DNA was extracted using standard phenol and chloroform extraction method, and the target gene was amplified through PCR by specific primers. Quality and ...

  9. Effect of ruminal administration of Escherichia coli wild type or a genetically modified strain with enhanced high nitrite reductase activity on methane emission and nitrate toxicity in nitrate-infused sheep.

    Science.gov (United States)

    Sar, C; Mwenya, B; Pen, B; Takaura, K; Morikawa, R; Tsujimoto, A; Kuwaki, K; Isogai, N; Shinzato, I; Asakura, Y; Toride, Y; Takahashi, J

    2005-11-01

    The effects of two kinds of Escherichia coli (E. coli) strain, wild-type E. coli W3110 and E. coli nir-Ptac, which has enhanced NO(2) reduction activity, on oral CH(4) emission and NO(3) toxicity in NO(3)-treated sheep were assessed in a respiratory hood system in a 4 x 6 Youden square design. NO(3) (1.3 g NaNO(3)/kg(0.75) body weight) and/or E. coli strains were delivered into the rumen through a fistula as a single dose 30 min after the morning meal. Escherichia coli cells were inoculated for sheep to provide an initial E. coli cell density of optical density at 660 nm of 2, which corresponded to 2 x 10(10) cells/ml. The six treatments consisted of saline, E. coli W3110, E. coli nir-Ptac, NO(3), NO(3) plus E. coli W3110, and NO(3) plus E. coli nir-Ptac. CH(4) emission from sheep was reduced by the inoculation of E. coli W3110 or E. coli nir-Ptac by 6 % and 12 %, respectively. NO(3) markedly inhibited CH(4) emission from sheep. Compared with sheep given NO(3) alone, the inoculation of E. coli W3110 to NO(3)-infused sheep lessened ruminal and plasma toxic NO(2) accumulation and blood methaemoglobin production, while keeping ruminal methanogenesis low. Ruminal and plasma toxic NO(2) accumulation and blood methaemoglobin production in sheep were unaffected by the inoculation of E. coli nir-Ptac. These results suggest that ruminal methanogenesis may be reduced by the inoculation of E. coli W3110 or E. coli nir-Ptac. The inoculation of E. coli W3110 may abate NO(3) toxicity when NO(3) is used to inhibit CH(4) emission from ruminants.

  10. Assessment of pit latrines in a peri-urban community in KwaZulu-Natal (South Africa) as a source of antibiotic resistant E. coli strains.

    Science.gov (United States)

    Beukes, Lorika S; King, Tracy L B; Schmidt, Stefan

    2017-11-01

    Due to the frequent use of antibiotics and recurring illnesses related to multidrug-resistant (MDR) bacteria in South Africa, we determined if MDR Escherichia coli were present in pit latrine fecal sludge samples obtained from a peri-urban community in KwaZulu-Natal, South Africa. The abundance of E. coli in pit latrine samples was established using a most probable number (MPN) method with species confirmation done using biochemical tests and polymerase chain reaction (PCR). Forty-four randomly selected E. coli pit latrine isolates were further characterized, using the European committee on antimicrobial susceptibility testing (EUCAST) disk diffusion method to establish antibiotic resistance profiles for these E. coli isolates. The resulting MPN values for E. coli ranged from one to 6.2 log 10 MPN per gram of fresh pit latrine fecal sludge. While only 3 out of 44 E. coli pit latrine isolates showed no resistance to any of the 12 tested antibiotics, most isolates were resistant to two or more antibiotics. The majority of isolates showed resistance to at least one of the two tested aminoglycosides, one isolate showed resistance to the carbapenem ertapenem, and although resistance was not detected for tigecycline four pit latrine E. coli isolates showed intermediate resistance to this antibiotic. However, about 14% of the E. coli pit latrine isolates were categorized as MDR, all of which showed resistance to four or more antibiotics. The presence of MDR E. coli strains in pit latrine samples demonstrates that these facilities are potential sources for MDR bacteria. Copyright © 2017 Elsevier GmbH. All rights reserved.

  11. Improvement on the yield of polyhydroxyalkanotes production from cheese whey by a recombinant Escherichia coli strain using the proton suicide methodology.

    Science.gov (United States)

    Pais, Joana; Farinha, Inês; Freitas, Filomena; Serafim, Luísa S; Martínez, Virginia; Martínez, Juan Carlos; Arévalo-Rodríguez, Miguel; Auxiliadora Prieto, M; Reis, Maria A M

    2014-02-05

    In this work Escherichia coli strain CML3-1 was engineered through the insertion of Cupriavidus necator P(3HB)-synthesis genes, fused to a lactose-inducible promoter, into the chromosome, via transposition-mediated mechanism. It was shown that polyhydroxyalkanotes (PHAs) production by this strain, using cheese whey, was low due to a significant organic acids (OA) synthesis. The proton suicide method was used as a strategy to obtain an E. coli mutant strain with a reduced OA-producing capacity, aiming at driving bacterial metabolism toward PHAs synthesis. Thirteen E. coli mutant strains were obtained and tested in shake flask assays, using either rich or defined media supplemented with lactose. P8-X8 was selected as the best candidate strain for bioreactor fed-batch tests using cheese whey as the sole carbon source. Although cell growth was considerably slower for this mutant strain, a lower yield of OA on substrate (0.04 Cmol(OA)/Cmol(lac)) and a higher P(3HB) production (18.88 g(P(3HB))/L) were achieved, comparing to the original recombinant strain (0.11 Cmol(OA)/Cmol(lac) and 7.8 g(P(3HB))/L, respectively). This methodology showed to be effective on the reduction of OA yield by consequently improving the P(3HB) yield on lactose (0.28 Cmol (P(3HB))/Cmol(lac) vs 0.10 Cmol(P(3HB))/Cmol(lac) of the original strain). Copyright © 2013 Elsevier Inc. All rights reserved.

  12. [Genetic diversity of extraintestinal Escherichia coli strains producers of beta-lactamases TEM, SHV and CTX-M associated with healthcare].

    Science.gov (United States)

    Varela, Yasmin; Millán, Beatriz; Araque, María

    2017-06-01

    There are few reports from Venezuela describing the genetic basis that sustains the pathogenic potential and phylogenetics of Escherichia coli extraintestinal strains isolated in health care units. To establish the genetic diversity of extraintestinal E. coli strains producers of betalactamases TEM, SHV and CTX-M associated with healthcare. We studied a collection of 12 strains of extraintestinal E. coli with diminished sensitivity to broad-spectrum cephalosporins. Antimicrobial susceptibility was determined by minimum inhibitory concentration. We determined the phylogenetic groups, virulence factors and genes encoding antimicrobial resistance using PCR, and clonal characterization by repetitive element palindromic-PCR rep-PCR. All strains showed resistance to cephalosporins and joint resistance to quinolones and aminoglycosides. The phylogenetic distribution showed that the A and B1 groups were the most frequent, followed by D and B2. We found all the virulence factors analyzed in the B2 group, and fimH gene was the most frequent among them. We found blaCTX-M in all strains,with a higher prevalence of blaCTX-M-8; two of these strains showed coproduction of blaCTX-M-9 and were genetically identified as blaCTXM-65 and blaCTX-M-147 by sequencing. The strains under study showed genetic diversity, hosting a variety of virulence genes, as well as antimicrobial resistance with no particular phylogroup prevalence. This is the first report of blaCTX-M alleles in Venezuela and in the world associated to non-genetically related strains isolated in health care units, a situation that deserves attention, as well as the rationalization of antimicrobials use.

  13. Library sequencing strategies for comparative analysis of stress resistance mechanisms in Escherichia coli strains

    DEFF Research Database (Denmark)

    Lennen, Rebecca; Bonde, Ida; Koza, Anna

    2014-01-01

    Transposon insertion sequencing (Tn-Seq) has recently emerged as a powerful next-generation sequencing method that enables querying the contributions of all genes in a bacterial genome toward the fitness of a growing organism. In this method, transposon insertion mutant libraries are constructed...... in metabolic flux distributions and regulation of gene expression between strains. A number of direct targets for metabolic engineering of stress resistance via loss-of-function mutations were also discovered, and we show that deletion of a selection of these genes results in improved growth under the original...

  14. Dissemination and genetic support of broad-spectrum beta-lactam-resistant Escherichia coli strain isolated from two Tunisian hospitals during 2004-2012.

    Science.gov (United States)

    Ayari, Khaoula; Bourouis, Amel; Chihi, Hela; Mahrouki, Sihem; Naas, Thierry; Belhadj, Omrane

    2017-06-01

    The dissemination of extended-spectrum β-lactamase (ESBL)-producing bacteria presented a great concern worldwide. Gram-negative organisms such as Escherichia coli and Klebsiella pneumoniae are the most frequently isolated pathogens responsible for nosocomial infections. The aim of this study was to investigate and to follow the emergence of resistance and the characterization of Extended-Spectrum Beta-Lactamases (ESBL) among broad-spectrum beta-lactam-Escherichia coli clinical isolates recovered from the military hospital and Habib Thameur hospital in Tunisia. A total of 113 E.coli isolates obtained during the period 2004 through 2012 showed a significant degree of multi-resistance. Among these strains, the double-disk synergy test confirmed the ESBL phenotype in 46 isolates. These included 32(70%) strains from Hospital A and 14(30%) from Hospital B. The ESBL was identified as CTX-M-15. The ESBL resistance was transferred by a 60 kb plasmid CTXM-15-producing isolates were unrelated according to the PFGE analysis and characterization of the regions surrounding the blaCTX-M-15 showed the ISEcp1 elements located in the upstream region of the bla gene and 20 of them truncated by IS26. ESBL producing E. coli strains are a serious threat in the community in Tunisia and we should take into consideration any possible spread of such epidemiological resistance.

  15. Comparative genomics and experimental evolution of Escherichia coli BL21(DE3) strains reveal the landscape of toxicity escape from membrane protein overproduction.

    Science.gov (United States)

    Kwon, Soon-Kyeong; Kim, Seong Keun; Lee, Dae-Hee; Kim, Jihyun F

    2015-11-04

    Achieving sufficient yields of proteins in their functional form represents the first bottleneck in contemporary bioscience and biotechnology. To accomplish successful overexpression of membrane proteins in a workhorse organism such as E. coli, defined and rational optimization strategies based on an understanding of the genetic background of the toxicity-escape mechanism are desirable. To this end, we sequenced the genomes of E. coli C41(DE3) and its derivative C43(DE3), which were developed for membrane protein production. Comparative analysis of their genomes with those of their ancestral strain E. coli BL21(DE3) revealed various genetic changes in both strains. A series of E. coli variants that are able to tolerate transformation with or overexpression of membrane proteins were generated by in vitro evolution. Targeted sequencing of the evolved strains revealed the mutational hotspots among the acquired genetic changes. By these combinatorial approaches, we found non-synonymous changes in the lac repressor gene of the lac operon as well as nucleotide substitutions in the lacUV5 promoter of the DE3 region, by which the toxic effect to the host caused by overexpression of membrane proteins could be relieved. A mutation in lacI was demonstrated to be crucial for conferring tolerance to membrane protein overexpression.

  16. Diversity of Escherichia coli Strains Producing Extended-Spectrum β-Lactamases in Spain: Second Nationwide Study ▿

    Science.gov (United States)

    Díaz, Miguel A.; Hernández-Bello, José R.; Rodríguez-Baño, Jesús; Martínez-Martínez, Luis; Calvo, Jorge; Blanco, Jorge; Pascual, Alvaro

    2010-01-01

    The prevalence of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (ESBLEC) in Spain increased 8-fold from 2000 to 2006. ESBL type, clonal relationship, antimicrobial susceptibility, and clinical data about infections caused by ESBLEC are evaluated in a second nationwide study developed in 2006. From 1008 clinical isolates obtained over 2 months from 44 hospitals, 254 were used for further analysis. ESBL production was evaluated by synergy testing, PCR, and sequencing. Antimicrobial activity was evaluated by microdilution. The clonal relationship was evaluated by repetitive extragenic palindromic-PCR (REP-PCR). The O25b subtype and the new afa operon FM955459 were determined by triplex PCR in isolates producing CTX-M-15. Multilocus sequence typing was performed on these isolates. A total of 72% of all ESBLs were of the CTX-M type, 26.8% were of the SHV type, and 1.2% were of the TEM type. The most prevalent ESBLs were CTX-M-14 (119 isolates), SHV-12 (68 isolates), CTX-M-15 (37 isolates), and CTX-M-9 (21 isolates). By REP-PCR, 214 clones were detected. All but five CTX-M-15 ESBLEC isolates corresponded to the international O25b/ST131 clone. This clone had not been detected in the first study (published in 2000). Epidemiological and clinical features were studied in 304 representative patients. A total of 60% of the patients were older than 60 and had nonfatal underlying diseases, and 55% had recently received antibiotics. Urinary tract infections accounted for 71% of cases, and 9% were bacteremic. There has been a significant increase in the prevalence of ESBLEC in Spain, with most of these strains being CTX-M-producing isolates, including the pandemic O25b-ST131. SHV-12-producing E. coli remains an important cause of community-acquired infection. PMID:20519460

  17. Surface water disinfection by chlorination and advanced oxidation processes: Inactivation of an antibiotic resistant E. coli strain and cytotoxicity evaluation.

    Science.gov (United States)

    Miranda, Andreza Costa; Lepretti, Marilena; Rizzo, Luigi; Caputo, Ivana; Vaiano, Vincenzo; Sacco, Olga; Lopes, Wilton Silva; Sannino, Diana

    2016-06-01

    The release of antibiotics into the environment can result in antibiotic resistance (AR) spread, which in turn can seriously affect human health. Antibiotic resistant bacteria have been detected in different aquatic environments used as drinking water source. Water disinfection may be a possible solution to minimize AR spread but conventional processes, such as chlorination, result in the formation of dangerous disinfection by-products. In this study advanced oxidation processes (AOPs), namely H2O2/UV, TiO2/UV and N-TiO2/UV, have been compared with chlorination in the inactivation of an AR Escherichia coli (E. coli) strain in surface water. TiO2 P25 and nitrogen doped TiO2 (N-TiO2), prepared by sol-gel method at two different synthesis temperatures (0 and -20°C), were investigated in heterogeneous photocatalysis experiments. Under the investigated conditions, chlorination (1.0 mg L(-1)) was the faster process (2.5 min) to achieve total inactivation (6 Log). Among AOPs, H2O2/UV resulted in the best inactivation rate: total inactivation (6 Log) was achieved in 45 min treatment. Total inactivation was not observed (4.5 Log), also after 120 min treatment, only for N-doped TiO2 synthesized at 0°C. Moreover, H2O2/UV and chlorination processes were evaluated in terms of cytotoxicity potential by means of 3-(4,5-dime-thylthiazol-2-yl)-2,5-diphenylte-trazolium colorimetric test on a human-derived cell line and they similarly affected HepG2 cells viability. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Detection of ctx-M gene in ESBL-producing E. coli strains isolated from urinary tract infection in Semnan, Iran.

    Science.gov (United States)

    Tabar, Mahbobeh Mohammad; Mirkalantari, Shiva; Amoli, Rabeeh Izadi

    2016-07-01

    The incidence of urinary tract infections caused by Extended-Spectrum Beta Lactamase (ESBL) producing Escherichia coli (E. coli) strains due to long term and overuse of broad-spectrum cephalosporine is on the rise. CTX beta-lactamase type, a broad-spectrum beta-lactamase, has been expanding in many countries. The ctx gene is harbored on a plasmid that is spread between Enterobacteriaceae family, especially in E. coli. The aim of this study was to determine the pattern of antimicrobial resistance and investigate the prevalent ESBL phenotype and the ctx-M gene in E. coli isolated from patients with urinary tract infections (UTI) in Semnan. A cross sectional study was performed on 109 strains of E. coli isolated from the urine culture of patient suffering from a UTI referred to Shafa hospital (Semnan, Iran) during March-July 2015. Antimicrobial susceptibility testing was applied and the prevalence of the ESBL phenotype was confirmed using combination disk. PCR methods were completed for amplification of the bla ctx gene. Data were analyzed using SPSS version 18 software. One hundred ninety samples (4.16%) were identified as E. coli. Twenty one (26.6%) of E. coli were ESBL positive and 73.4% were ESBL negative. There was 100% susceptibility to imipeneme. Twenty (68.97%) out of 29 isolates were positive for the ctx-M gene, as detected by PCR. In urinary tract infections, antibiotic treatment was experimental and detailed information regarding the sensitivity of bacteria in the area can be useful to achieve the best treatment.

  19. View of the bacterial strains of Escherichia coli M-17 and its interaction with the nanoparticles of zinc oxide by means of atomic force microscopy

    Science.gov (United States)

    Sagitova, A.; Yaminsky, I.; Meshkov, G.

    2016-08-01

    Visualization of the structure of biological objects plays a key role in medicine, biotechnology, nanotechnology and IT-technology. Atomic force microscopy (AFM) is a promising method of studying of objects’ morphology and structure. In this work, AFM was used to determine the size and shape of the bacterial strains of Escherichia coli M-17 and visualization its interaction with the nanoparticles of zinc oxide. The suspension of E.coli bacteria was applied to natural mica and studied by contact mode using the FemtoScan multifunctional scanning probe microscope.

  20. Comparison of the incidence of pathogenic and antibiotic-resistant Escherichia coli strains in adult cattle and veal calf slaughterhouse effluents highlighted different risks for public health.

    Science.gov (United States)

    Um, Maryse Michèle; Barraud, Olivier; Kérourédan, Monique; Gaschet, Margaux; Stalder, Thibault; Oswald, Eric; Dagot, Christophe; Ploy, Marie-Cecile; Brugère, Hubert; Bibbal, Delphine

    2016-01-01

    The goal of this study was to investigate the involvement of bovine slaughterhouse effluents and biosolids in the risk of environmental dissemination of pathogenic and antibiotic-resistant Escherichia coli. Several samples were collected from one adult cattle and one veal calf slaughterhouse wastewater treatment plant (WWTP). The treatment process had no impact on the percentage of Shiga toxin-producing E. coli (STEC) and on the percentage of atypical enteropathogenic E. coli (aEPEC). A STEC O157:H7 was isolated from the thickened sludge of the adult cattle slaughterhouse. As thickened sludge is intended to be spread on agricultural lands, the detection of this pathogenic strain is a public health issue. The percentage of antibiotic-resistant E. coli was 5.0% and 87.5% in wastewater from the adult cattle and the veal calf slaughterhouse, respectively. These percentages were not significantly different after treatment. Integron-bearing E. coli isolates were only detected in the veal calf slaughterhouse WWTP with percentages above 50.0% for all sampling points whatever the step of the treatment process. Taken together, these findings highlighted the fact that different public health risks might be associated with adult cattle or veal calf slaughterhouses regarding the dissemination of pathogenic and antibiotic-resistant E. coli isolates into the environment. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Differential gene expression of three mastitis-causing Escherichia coli strains grown under planktonic, swimming, and swarming culture conditions

    Science.gov (United States)

    Escherichia coli is a leading cause of intramammary infections in dairy cattle and is typically transient in nature. However, in a minority of cases, E. coli can cause persistent infections. Although the mechanisms that allow for a persistent intramammary E. coli infection are not fully understood...

  2. Virulence factors, antibiotic resistance phenotypes and O-serogroups of Escherichia coli strains isolated from community-acquired urinary tract infection patients in Mexico.

    Science.gov (United States)

    Paniagua-Contreras, Gloria Luz; Monroy-Pérez, Eric; Rodríguez-Moctezuma, José Raymundo; Domínguez-Trejo, Pablo; Vaca-Paniagua, Felipe; Vaca, Sergio

    2017-08-01

    Uropathogenic Escherichia coli (UPEC) strains isolated from patients with community-acquired urinary tract infections (UTIs) were assessed to determine the prevalence of virulence genes, antibiotic resistance, and the O-serogroup of the strains. Consenting patients with community-acquired UTI were enrolled at Unidad Médica Familiar Number 64 (Instituto Mexicano del Seguro Social, Estado de Mexico, Mexico) and 321 urine samples were collected. Polymerase chain reaction (PCR) was used to assess 24 virulence genes and 14 O-serogroups. The Kirby-Bauer method was used to evaluate the antibiotic susceptibility of the isolated strains to 12 commonly used antibiotics. A total of 194 strains were identified as E. coli using standard biochemical tests, followed by PCR amplification of 16S ribosomal RNA gene. Only 58.2% of the strains belonged to the assessed 14 O-serogroups. The serogroups O25, O15, O8, and O75 were present in 20.6%, 17%, 6.1%, and 4.6% of strains, respectively. The most frequently occurring virulence genes among UPEC strains included kpsMT (92.2% strains), usp (87.1%), irp2 (79.3%), iha (64.9%), fim (61.3%), set (36%), astA (33.5%), pap (24.7%), and papGII (21.1%). In addition, 97% of the strains were multi-drug resistant (coresistance to 3-11 antibiotics). The isolated UPEC strains predominantly belonged to three serogroups (O25, O15, and O8), harboured numerous virulence genes, and are multiresistant to antibiotics. The findings of this study could be used to orient UTI treatment strategies and in epidemiological studies in Mexico. Copyright © 2015. Published by Elsevier B.V.

  3. The cytolethal distending toxin-IV cdt coding region in an avian pathogenic Escherichia coli (APEC) strain shows instability and irregular excision pattern.

    Science.gov (United States)

    Tóth, István; Schneider, György

    2015-12-01

    Cytolethal distending toxins (CDT) represent an emerging toxin family, widely distributed among pathogenic bacteria. The cdtABC genes in E. coli are either part of the genome of prophages, plasmid or pathogenicity island. In order to investigate the stability and the transfer potential of cdt-IV genes cdtB gene was replaced by chloramphenicol (Cm) resistance encoding cat gene in the avian pathogenic E. coli (APEC) strain E250. After consecutive passages in non-selective medium at 37 °C 7.6% (219/2900) of the investigated colonies of E250::cat strain became Cm-sensitive (Cm(S)). To reveal deletion mechanism 177 Cm(S) colonies were investigated for presence of cdtA, cdtC and cdtC associated gene by PCR. One hundred and sixteen colonies of the Cm(S) colonies (65.5%) showed partial or complete deletion in the cdt-IV region. Progressive loss of the upstream genes of the cdt cluster in E250 compared to other CDT-IV producing APEC strains and the fact that all the potential deletion patterns were identified, suggests the presence of an unstable hitherto unknown genomic region. The failure of in vitro transfer of cdt genes into a porcine EPEC E. coli strain suggests that the deletion of cdt-IV flanking genes alone do not promote the spread of cdt-IV.

  4. Disinfectant and antibiotic susceptibility profiles of Escherichia coli O157:H7 strains from cattle carcasses, feces, and hides and ground beef from the United States.

    Science.gov (United States)

    Beier, Ross C; Poole, Toni L; Brichta-Harhay, Dayna M; Anderson, Robin C; Bischoff, Kenneth M; Hernandez, Charles A; Bono, James L; Arthur, Terrance M; Nagaraja, T G; Crippen, Tawni L; Sheffield, Cynthia L; Nisbet, David J

    2013-01-01

    The disinfectant and antibiotic susceptibility profiles of 344 Escherichia coli O157:H7 strains from cattle carcasses, feces, and hides and ground beef from the United States were determined. A low prevalence of antibiotic resistance was observed (14%). The highest prevalences of resistance were to sulfisoxazole (10.5%), tetracycline (9.9%), streptomycin (7%), and chloramphenicol (4.9%). Four strains were resistant to eight antibiotics (two strains from ground beef and one strain each from hide and preevisceration carcass swabs of cull cattle at harvest). Pulsed-field gel electrophoresis analysis of the E. coli O157:H7 strains revealed two major groups (designated 1 and 2) composed of 17 and 20 clusters, respectively. Clusters 1A, 1B, 1C, and 1G.1 were associated with multidrug-resistant strains. There was no observed correlation between disinfectant resistance and antibiotic resistance. Sixty-nine (20%) of the 344 strains were resistant to chlorhexidine or benzalkonium chloride or the MICs of benzyldimethyldodecylammonium chloride were elevated. Inducible resistance was observed at elevated concentrations of antibiotics (1.4%) and disinfectants (6.1%). The highest rate of disinfectant inducible resistance was to OdoBan, quaternary ammonium chlorides, and the surface disinfectants F25, FS512, and MG, which are used in dairies, restaurants, and food processing plants. High MICs (1,024 to 4,096 m g/ml) of acetic, lactic, and citric acids were found. The decreasing order of acid potency based on molar MICs (MICs(molar)) was acetic, citric, and lactic acid. The correlation of the concentration of dissociated organic acids and MICs(molar) strongly suggests that the observed inhibition of E. coli O157:H7 was primarily due to dissociated forms of the acids.

  5. Polymorphism of genes encoding PmrAB in colistin-resistant strains of Escherichia coli and Salmonella enterica isolated from poultry and swine.

    Science.gov (United States)

    Quesada, Alberto; Porrero, M Concepción; Téllez, Sonia; Palomo, Gonzalo; García, María; Domínguez, Lucas

    2015-01-01

    To detect the occurrence of low susceptibility to colistin (polymyxin E), a last-resort antimicrobial, among enterobacteria isolated from samples of animal origin (poultry and swine) and to find out the molecular basis of colistin resistance. Salmonella enterica and Escherichia coli were isolated from eggs and swine samples. Bacterial strains were screened for colistin resistance by using MIC determinations interpreted according to EUCAST recommendations. pmrAB genes were amplified by PCR from bacterial isolates and their sequences were characterized. Nine colistin-resistant strains were detected in a collection of 739 enterobacteria (S. enterica and E. coli) isolated from animal samples taken in different environments. Sequences encoding the PmrAB two-component sensor-regulator from two colistin-resistant E. coli strains isolated from swine faeces presented three non-synonymous polymorphisms, producing the variants 39S → I and 81R → S of PmrA and 161V → G of PmrB, among which the involvement of mutations in PmrA-81 and PmrB-161 in resistance to the antimicrobial had been previously shown. No variation at the protein level was detected after analysis of PmrAB sequences from seven colistin-resistant S. enterica strains. E. coli strains carrying mutations in PmrAB that confer resistance to polymyxins, which might have evolved in vivo and have been rarely detected, are described for the first time in enterobacteria isolated from animals. © The Author 2014. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  6. Genomic diversity and fitness of E. coli strains recovered from the intestinal and urinary tracts of women with recurrent urinary tract infection.

    Science.gov (United States)

    Chen, Swaine L; Wu, Meng; Henderson, Jeffrey P; Hooton, Thomas M; Hibbing, Michael E; Hultgren, Scott J; Gordon, Jeffrey I

    2013-05-08

    Urinary tract infections (UTIs) are common in women, and recurrence is a major clinical problem. Most UTIs are caused by uropathogenic Escherichia coli (UPEC). UPEC are generally thought to migrate from the gut to the bladder to cause UTI. UPEC form specialized intracellular bacterial communities in the bladder urothelium as part of a pathogenic mechanism to establish a foothold during acute stages of infection. Evolutionarily, such a specific adaptation to the bladder environment would be predicted to result in decreased fitness in other habitats, such as the gut. To examine this prediction, we characterized 45 E. coli strains isolated from the feces and urine of four otherwise healthy women with recurrent UTI. Multilocus sequence typing and whole genome sequencing revealed that two patients maintained a clonal population in both these body habitats throughout their recurrent UTIs, whereas the other two exhibited a wholesale shift in the dominant UPEC strain colonizing both sites. In vivo competition studies in mouse models, using isolates taken from one of the patients with a wholesale population shift, revealed that the strain that dominated her last UTI episode had increased fitness in both the gut and the bladder relative to the strain that dominated in preceding episodes. Increased fitness correlated with differences in the strains' gene repertoires and carbohydrate and amino acid utilization profiles. Thus, UPEC appear capable of persisting in both the gut and urinary tract without a fitness trade-off, emphasizing the need to widen our consideration of potential reservoirs for strains causing recurrent UTI.

  7. Effect of orally administered probiotic E. coli strain Nissle 1917 on intestinal mucosal immune cells of healthy young pigs.

    Science.gov (United States)

    Duncker, Swantje C; Lorentz, Axel; Schroeder, Bernd; Breves, Gerhard; Bischoff, Stephan C

    2006-06-15

    Several beneficial effects of probiotics have been described in studies using rodent disease models and in human patients; however, the underlying mechanisms remained mostly unclear. Only a few studies focused on the effects of probiotics on the intestinal mucosal immune system. Here, we studied the effect of the probiotic strain E. coli Nissle 1917 (EcN) administered orally to young pigs at two concentrations (10(9) and 10(11)CFU/d for 21 days) on the gut-associated lymphatic tissue. This probiotic strain was shown recently to reduce recurrence of inflammation in ulcerative colitis patients. We quantified the number and distribution of intestinal immune cells (granulocytes, mast cells, CD4+, CD8+, CD25+, IgA+ lymphocytes) and the mucosal mRNA expression of cytokines (IFN-gamma, TNF-alpha, TGF-beta, IL-10) and antimicrobial peptides (PR-39, NK-lysin, prepro-defensin-beta 1, protegrins). The number and distribution of cells were highly different between small intestinal and colon segments in all groups, but were not influenced by EcN, except high dose EcN fed pigs (10(11) CFU/d) showing an increase in mucosal CD8+ cells in the ascending colon. The mRNA analysis revealed no changes associated with EcN feeding. In conclusion, according to our analyses EcN has only minor effects on the distribution of mucosal immune cells in the gut of healthy individuals. The well-established preventive effects of EcN might therefore be relate to other mechanisms than simple modulation of immune cell distribution.

  8. Targeted Amplicon Sequencing for Single-Nucleotide-Polymorphism Genotyping of Attaching and Effacing Escherichia coli O26:H11 Cattle Strains via a High-Throughput Library Preparation Technique.

    Science.gov (United States)

    Ison, Sarah A; Delannoy, Sabine; Bugarel, Marie; Nagaraja, Tiruvoor G; Renter, David G; den Bakker, Henk C; Nightingale, Kendra K; Fach, Patrick; Loneragan, Guy H

    2015-11-13

    Enterohemorrhagic Escherichia coli (EHEC) O26:H11, a serotype within Shiga toxin-producing E. coli (STEC) that causes severe human disease, has been considered to have evolved from attaching and effacing E. coli (AEEC) O26:H11 through the acquisition of a Shiga toxin-encoding gene. Targeted amplicon sequencing using next-generation sequencing technology of 48 phylogenetically informative single-nucleotide polymorphisms (SNPs) and three SNPs differentiating Shiga toxin-positive (stx-positive) strains from Shiga toxin-negative (stx-negative) strains were used to infer the phylogenetic relationships of 178 E. coli O26:H11 strains (6 stx-positive strains and 172 stx-negative AEEC strains) from cattle feces to 7 publically available genomes of human clinical strains. The AEEC cattle strains displayed synonymous SNP genotypes with stx2-positive sequence type 29 (ST29) human O26:H11 strains, while stx1 ST21 human and cattle strains clustered separately, demonstrating the close phylogenetic relatedness of these Shiga toxin-negative AEEC cattle strains and human clinical strains. With the exception of seven stx-negative strains, five of which contained espK, three stx-related SNPs differentiated the STEC strains from non-STEC strains, supporting the hypothesis that these AEEC cattle strains could serve as a potential reservoir for new or existing pathogenic human strains. Our results support the idea that targeted amplicon sequencing for SNP genotyping expedites strain identification and genetic characterization of E. coli O26:H11, which is important for food safety and public health. Copyright © 2016 Ison et al.

  9. Simplified process for ethanol production from sugarcane bagasse using hydrolysate-resistant Escherichia coli strain MM160.

    Science.gov (United States)

    Geddes, C C; Mullinnix, M T; Nieves, I U; Peterson, J J; Hoffman, R W; York, S W; Yomano, L P; Miller, E N; Shanmugam, K T; Ingram, L O

    2011-02-01

    Hexose and pentose sugars from phosphoric acid pretreated sugarcane bagasse were co-fermented to ethanol in a single vessel (SScF), eliminating process steps for solid-liquid separation and sugar cleanup. An initial liquefaction step (L) with cellulase was included to improve mixing and saccharification (L+SScF), analogous to a corn ethanol process. Fermentation was enabled by the development of a hydrolysate-resistant mutant of Escherichia coli LY180, designated MM160. Strain MM160 was more resistant than the parent to inhibitors (furfural, 5-hydroxymethylfurfural, and acetate) formed during pretreatment. Bagasse slurries containing 10% and 14% dry weight (fiber plus solubles) were tested using pretreatment temperatures of 160-190°C (1% phosphoric acid, 10 min). Enzymatic saccharification and inhibitor production both increased with pretreatment temperature. The highest titer (30 g/L ethanol) and yield (0.21 g ethanol/g bagasse dry weight) were obtained after incubation for 122 h using 14% dry weight slurries of pretreated bagasse (180°C). Copyright © 2010 Elsevier Ltd. All rights reserved.

  10. Analysis of the production process of optically pure D-lactic acid from raw glycerol using engineered Escherichia coli strains.

    Science.gov (United States)

    Posada, John A; Cardona, Carlos A; Gonzalez, Ramon

    2012-02-01

    Glycerol has become an ideal feedstock for producing fuels and chemicals. Here, five technological schemes for optically pure D: -lactic acid production from raw glycerol were designed, simulated, and economically assessed based on five fermentative scenarios using engineered Escherichia coli strains. Fermentative scenarios considered different qualities of glycerol (pure, 98 wt.%, and crude, 85 wt.%) with concentrations ranging from 20 to 60 g/l in the fermentation media, and two fermentation stages were also analyzed. Raw glycerol (60 wt.%) was considered as the feedstock feeding the production process in all cases; then a purification process of raw glycerol up to the required quality was required. Simulation processes were carried out using Aspen Plus, while economic assessments were performed using Aspen Icarus Process Evaluator. D: -Lactic acid recovery and purification processes were based on reactive extraction with tri-n-octylamine using dichloromethane as active extractant agent. The use of raw glycerol represents only between 2.4% and 7.8% of the total production costs. Also, the total production costs obtained of D: -lactic acid in all cases were lower than its sale price indicating that these processes are potentially profitable. Thus, the best configuration process requires the use of crude glycerol diluted at 40 g/l with total glycerol consumption and with D: -lactic acid recovering by reactive extraction. The lowest obtained total production cost was 1.015 US$/kg with a sale price/production cost ratio of 1.53.

  11. Expression Optimizing and Purification of Recombinant Human Leukemia Inhibitory Factor Produced in E. coli Strain BL21

    Directory of Open Access Journals (Sweden)

    Houman Kahroba

    2015-02-01

    Full Text Available Background: Leukemia inhibitory factor (LIF is a glycoprotein, categorized as a subfamily of interleukin 6 cytokines which is known in many mammolals. A pluripotent cytokine with a wide biological function range has numerous effects on target cells. The LIF regulates neuron survival, hematopoiesis and seen in LIF-/- knockout mice affects blastocyst implantation, also acts as pre-inflammolatory cytokine, and regulates immolune response. Further, it is able to maintain stem cells poly potency. The main object of present work was expression, optimizing, and purification of recombinant human leukemia inhibitory factor (rhLIF. Materials and Methods: In this experimental study, Pet28 (+ carrying the LIF gene and kanamycin resistance marker was cloned in E. coli strain BL21. The induction was optimized by altering 3 factors including the temperature, the induction time, and the concentration of the Isopropyl β-D-1-thiogalactopyranoside (IPTG as inducer. The purification of the recombinant human LIF (rhLIF was done by single step affinity chromatography. After the purification, method accuracy was proved by Sodium dodecyl sulfate (SDS -PAGE electrophoresis and Western blotting. Results: Optimizing of the expression was reached by changing various parameters, and purification has been done successful. Conclusion: rhLIF undergoes modification by glycosylation to get its full functionality. The produced rhLIF in prokaryotic host in this work is lacking of glycosylation. However, its proper function should be evaluated in further studies.

  12. Detection and coexistence of six categories of resistance genes in Escherichia coli strains from chickens in Anhui Province, China

    Directory of Open Access Journals (Sweden)

    Lin Li

    2015-12-01

    Full Text Available The aim of this study was to characterise the prevalence of class 1 integrons and gene cassettes, tetracycline-resistance genes, phenicol-resistance genes, 16S rRNA methylase genes, extended-spectrum β-lactamase genes and plasmid-mediated fluoroquinolone resistance determinants in 184 Escherichia coli isolates from chickens in Anhui Province, China. Susceptibility to 15 antimicrobials was determined using broth micro-dilution. Polymerase chain reaction and DNA sequencing were used to characterise the molecular basis of the antibiotic resistance. High rates of antimicrobial resistance were observed; 131 out of the 184 (72.3% isolates were resistant to at least six antimicrobial agents. The prevalences of class 1 integrons, tetracycline-resistance genes, phenicol-resistance genes, 16S rRNA methylase genes, extended-spectrum β-lactamase genes and plasmid-mediated fluoroquinolone resistance determinants were 49.5, 17.4, 15.8, 0.5, 57.6 and 46.2%, respectively. In 82 isolates, 48 different kinds of coexistence of the different genes were identified. Statistical (χ2 analysis showed that the resistance to amoxicillin, doxycycline, florfenicol, ofloxacin and gentamicin had significant differences (P<0.01 or 0.01strains that carried and did not carry the resistance genes, which showed a certain correlation between antimicrobial resistance and the presence of resistance genes.

  13. Inhibitory potential of strepthonium A against Shiga toxin production in enterohemorrhagic Escherichia coli (EHEC) strain EDL933.

    Science.gov (United States)

    Cheng, Cheng; Balasubramanian, Srikkanth; Fekete, Agnes; Krischke, Markus; Mueller, Martin J; Hentschel, Ute; Oelschlaeger, Tobias A; Abdelmohsen, Usama Ramadan

    2017-12-01

    The production of shiga toxin (Stx) is a critical step in the establishment and progress of enterohemorrhagic Escherichia coli (EHEC) infections. The possible release of Stx from dead and dying bacteria, and the risk of resistance development have restricted the usage of antibiotics against EHEC. The chlorinated quaternary ammonium compound, strepthonium A, was isolated from the culture of Streptomyces sp. SBT345 that was cultivated from the Mediterranean sponge Agelas oroides. The structure was elucidated and confirmed by spectroscopic analyses including 1D and 2D NMR, ESI-HRMS, as well as ESI-HRMS 2 . Strepthonium A follows Lipinski's rule of five with respect to its molecular weight, CLogP values and the number of hydrogen acceptors and donors. Verotoxin ELISA assay demonstrated that Strepthonium A reduced the Stx production in EHEC strain EDL933 at 80 μM concentration without growth inhibition. This study demonstrates the potential of strepthonium A in restraining the production of Stx in EHEC infections.

  14. Significant rewiring of the transcriptome and proteome of an Escherichia coli strain harboring a tailored exogenous global regulator IrrE.

    Directory of Open Access Journals (Sweden)

    Tingjian Chen

    Full Text Available Cell reprogramming for microorganisms via engineered or artificial transcription factors and RNA polymerase mutants has presented a powerful tool for eliciting complex traits that are practically useful particularly for industrial strains, and for understanding at the global level the regulatory network of gene transcription. We previously further showed that an exogenous global regulator IrrE (derived from the extreme radiation-resistant bacterium Deinococcus radiodurans can be tailored to confer Escherichia coli (E. coli with significantly enhanced tolerances to different stresses. In this work, based on comparative transcriptomic and proteomic analyses of the representative strains E1 and E0, harboring the ethanol-tolerant IrrE mutant E1 and the ethanol-intolerant wild type IrrE, respectively, we found that the transcriptome and proteome of E. coli were extensively rewired by the tailored IrrE protein. Overall, 1196 genes (or approximately 27% of E. coli genes were significantly altered at the transcriptomic level, including notably genes in the nitrate-nitrite-nitric oxide (NO pathway, and genes for non-coding RNAs. The proteomic profile revealed significant up- or downregulation of several proteins associated with syntheses of the cell membrane and cell wall. Analyses of the intracellular NO level and cell growth under reduced temperature supported a close correlation between NO and ethanol tolerance, and also suggests a role for membrane fluidity. The significantly different omic profiles of strain E1 indicate that IrrE functions as a global regulator in E. coli, and that IrrE may be evolved for other cellular tolerances. In this sense, it will provide synthetic biology with a practical and evolvable regulatory "part" that operates at a higher level of complexity than local regulators. This work also suggests a possibility of introducing and engineering other exogenous global regulators to rewire the genomes of microorganism cells.

  15. Detection and antibiotic sensitivity pattern of avian pathogenic Escherichia coli strains among rural chickens in the arid region of north-eastern Nigeria

    Directory of Open Access Journals (Sweden)

    Yaqub A Geidam

    2012-12-01

    Full Text Available Aim: To know the prevalence of avian pathogenic Escherichia coli (APEC strains among adult apparently healthy rural chickens slaughtered in Maiduguri, north-eastern Nigeria. Materials and Methods: Cloacal swabs were examined by Gram staining, biochemical tests such as indole, methyl red, Voges-Proskauer and citrate (IMVC tests and serotype by standard slide agglutination test with antisera against somatic antigen using six monospecific “O” antisera to E. coli belonging to the avian pathogenic E. coli group namely O1, O2, O26, O78, O86 and O141. The sensitivity of the isolated APEC strains to 10 antibiotics of human and veterinary use was also determined. Results: Out of a total of 510 samples examined, 356 (69.8% were positive for E. coli. Of this number 20 (5.6% samples were positive for O1, 20 (5.6% for O2, 0 (0% for O26, 25 (7.0% for O78, 25 (7.0% for O86 and 24 (6.7% for O141 serotypes. The remaining 242 (68.0% E. coli isolates were non typable with the 6 sera of avian pathogenic E. coli strains used for the study. The sensitivity profile of the isolates showed complete resistance of all the isolates against ampicillin, tetracycline, nalidixic acid and cefuroxime, while on the other hand all the isolates showed very high susceptibility to oxofloxacin followed by ciprofloxacin and gentamycin. The result of this study suggests that multiple-antimicrobial-resistant APEC isolates are present in rural chickens in Maiduguri, north-eastern Nigeria. In addition to animal health problems created by the resistant strains, there may also be potential danger posed to human health because these strains could easily infect humans through the food chain. Conclusion: The result of this study suggests that multiple-antimicrobial-resistant APEC isolates are present in rural chickens in Maiduguri, north-eastern Nigeria. Consequently, introduction of surveillance programs to monitor antimicrobial resistance of pathogenic bacteria is strongly recommended in

  16. E. coli

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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 .

  17. [Description and investigation of an outbreak of extended-spectrum beta-lactamase producing Escherichia coli strain in a neonatal unit].

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