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Sample records for coli heat-labile enterotoxin

  1. GM1 erythroimmunoassay for detection and titration of Escherichia coli heat-labile enterotoxin.

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    Germani, Y; Bégaud, E; Guesdon, J L; Moreau, J P

    1986-01-01

    A GM1 ganglioside erythroimmunoassay for the detection of heat-labile Escherichia coli enterotoxin (LT) was developed for use in poorly equipped laboratories in developing countries. This assay is based on the immunological similarity between Vibrio cholerae toxin and LT and uses cholera toxin antiserum and sheep anti-rabbit immunoglobulin covalently coupled to sheep erythrocytes as conjugate. This assay has the following advantages over other currently available techniques: the reagents it u...

  2. Parenteral adjuvant potential of recombinant B subunit of Escherichia coli heat-labile enterotoxin

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    Carlos Eduardo Pouey da Cunha

    Full Text Available BACKGROUND The B subunit of Escherichia coli heat-labile enterotoxin (LTB is a potent mucosal immune adjuvant. However, there is little information about LTB's potential as a parenteral adjuvant. OBJECTIVES We aimed at evaluating and better understanding rLTB's potential as a parenteral adjuvant using the fused R1 repeat of Mycoplasma hyopneumoniae P97 adhesin as an antigen to characterise the humoral immune response induced by this construct and comparing it to that generated when aluminium hydroxide is used as adjuvant instead. METHODS BALB/c mice were immunised intraperitoneally with either rLTBR1 or recombinant R1 adsorbed onto aluminium hydroxide. The levels of systemic anti-rR1 antibodies (total Ig, IgG1, IgG2a, and IgA were assessed by enzyme-linked immunosorbent assay (ELISA. The ratio of IgG1 and IgG2a was used to characterise a Th1, Th2, or mixed Th1/Th2 immune response. FINDINGS Western blot confirmed rR1, either alone or fused to LTB, remained antigenic; anti-cholera toxin ELISA confirmed that LTB retained its activity when expressed in a heterologous system. Mice immunised with the rLTBR1 fusion protein produced approximately twice as much anti-rR1 immunoglobulins as mice vaccinated with rR1 adsorbed onto aluminium hydroxide. Animals vaccinated with either rLTBR1 or rR1 adsorbed onto aluminium hydroxide presented a mixed Th1/Th2 immune response. We speculate this might be a result of rR1 immune modulation rather than adjuvant modulation. Mice immunised with rLTBR1 produced approximately 1.5-fold more serum IgA than animals immunised with rR1 and aluminium hydroxide. MAIN CONCLUSIONS The results suggest that rLTB is a more powerful parenteral adjuvant than aluminium hydroxide when administered intraperitoneally as it induced higher antibody titres. Therefore, we recommend that rLTB be considered an alternative adjuvant, even if different administration routes are employed.

  3. Heat-Labile Enterotoxin: Beyond G M1 Binding

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    Benjamin Mudrak

    2010-06-01

    Full Text Available Enterotoxigenic Escherichia coli (ETEC is a significant source of morbidity and mortality worldwide. One major virulence factor released by ETEC is the heat-labile enterotoxin LT, which is structurally and functionally similar to cholera toxin. LT consists of five B subunits carrying a single catalytically active A subunit. LTB binds the monosialoganglioside GM1, the toxin’s host receptor, but interactions with A-type blood sugars and E. coli lipopolysaccharide have also been identified within the past decade. Here, we review the regulation, assembly, and binding properties of the LT B-subunit pentamer and discuss the possible roles of its numerous molecular interactions.

  4. Type II heat-labile enterotoxins from 50 diverse Escherichia coli isolates belong almost exclusively to the LT-IIc family and may be prophage encoded.

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    Michael G Jobling

    Full Text Available Some enterotoxigenic Escherichia coli (ETEC produce a type II heat-labile enterotoxin (LT-II that activates adenylate cyclase in susceptible cells but is not neutralized by antisera against cholera toxin or type I heat-labile enterotoxin (LT-I. LT-I variants encoded by plasmids in ETEC from humans and pigs have amino acid sequences that are ≥ 95% identical. In contrast, LT-II toxins are chromosomally encoded and are much more diverse. Early studies characterized LT-IIa and LT-IIb variants, but a novel LT-IIc was reported recently. Here we characterized the LT-II encoding loci from 48 additional ETEC isolates. Two encoded LT-IIa, none encoded LT-IIb, and 46 encoded highly related variants of LT-IIc. Phylogenetic analysis indicated that the predicted LT-IIc toxins encoded by these loci could be assigned to 6 subgroups. The loci corresponding to individual toxins within each subgroup had DNA sequences that were more than 99% identical. The LT-IIc subgroups appear to have arisen by multiple recombinational events between progenitor loci encoding LT-IIc1- and LT-IIc3-like variants. All loci from representative isolates encoding the LT-IIa, LT-IIb, and each subgroup of LT-IIc enterotoxins are preceded by highly-related genes that are between 80 and 93% identical to predicted phage lysozyme genes. DNA sequences immediately following the B genes differ considerably between toxin subgroups, but all are most closely related to genomic sequences found in predicted prophages. Together these data suggest that the LT-II loci are inserted into lambdoid type prophages that may or may not be infectious. These findings raise the possibility that production of LT-II enterotoxins by ETEC may be determined by phage conversion and may be activated by induction of prophage, in a manner similar to control of production of Shiga-like toxins by converting phages in isolates of enterohemmorhagic E. coli.

  5. [Escherichia coli heat-labile enterotoxin B subunit enhances the immune response against canine parvovirus VP2 in mice immunized by VP2 DNA vaccine].

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    Han, Dongmei; Zhong, Fei; Li, Xiujin; Wang, Wei; Wang, Xingxing; Pan, Sumin

    2011-01-01

    To investigate the effect of Escherichia coli heat-labile enterotoxin (LT) B subunit (LTB) gene on canine parvovirus (CPV) VP2 gene vaccine. The LTB gene was amplified by PCR from genomic DNA of E. coli 44815 strain. The VP2-70 fragment (210 bp) encoding major epitope of VP2 (70 amino acids) was amplified by PCR from a plasmid encoding VP2 gene. VP2-70 and LTB genes were inserted into the eukaryotic vector to construct VP2-70 gene,LTB gene and VP2-70-LTB fused gene vectors. The mice were immunized with VP2-70 vector, VP2-70-LTB fused vector, or VP2-70 vector plus LTB vector, respectively. The antibody titers at the different time were measured by using ELISA method. The spleen lymphocyte proliferation activity was analyzed by 3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. The sequence of VP2-70 and LTB genes was identified. The recombinant VP2-70 and LTB proteins could be expressed in HEK293T cells in a secretory manner. The mice immunized with VP2-70 vector, VP2-70-LTB vector or VP2-70 vector plus LTB vector could generate the specific antibody against VP2 protein. The antibody titer immunized with VP2-70-LTB vector reached 1:5120 at 35 d post immunization, significantly higher than that of other two groups (P vaccine in mice.

  6. Incorporation of membrane-anchored flagellin or Escherichia coli heat-labile enterotoxin B subunit enhances the immunogenicity of rabies virus-like particles in mice and dogs

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    Yinglin eQi

    2015-03-01

    Full Text Available Rabies remains an important worldwide public health threat, so safe, effective and affordable vaccines are still being sought. Virus-like particle (VLP-based vaccines targeting various viral pathogens have been successfully produced, licensed and commercialized. Here, we designed and constructed two chimeric rabies virus-like particles (cRVLPs containing rabies virus (RABV glycoprotein (G, matrix (M protein, and membrane-anchored flagellin (EVLP-F or Escherichia coli heat-labile enterotoxin B subunit (EVLP-L as molecular adjuvants to enhance the immune response against rabies. The immunogenicity and potential of cRVLPs as novel rabies vaccine were evaluated by intramuscular vaccination in mouse and dog models. Mouse studies demonstrated that both EVLP-F and EVLP-L induced faster and larger virus-neutralizing antibodies (VNA responses and elicited greater numbers of CD4+ and CD8+ T cells secreting IFN-γ or IL-4 compared with a standard rabies VLP (sRVLP containing only G and M. Moreover, cRVLPs recruited and/or activated more B cells and dendritic cells in inguinal lymph nodes. EVLP-F induced a strong, specific IgG2a response but not an IgG1 response, suggesting the activation of Th1 class immunity; in contrast, Th2 class immunity was observed with EVLP-L. The significantly enhanced humoral and cellular immune responses induced by cRVLPs provided complete protection against lethal challenge with RABV. Most importantly, dogs vaccinated with EVLP-F or EVLP-L exhibited increased VNA titers in sera and enhanced IFN-γ and IL-4 secretion from peripheral blood mononuclear cells. Taken together, these results illustrate that when incorporated into sRVLP, membrane-anchored flagellin and LTB possess strong adjuvant activity. EVLP-F and EVLP-L induce significantly enhanced RABV-specific humoral and cellular immune responses in both mouse and dog. Therefore, these cRVLPs may be developed as safe and more efficacious rabies vaccine candidate for animals.

  7. Immunogenicity of recombinant Lactobacillus casei-expressing F4 (K88) fimbrial adhesin FaeG in conjunction with a heat-labile enterotoxin A (LTAK63) and heat-labile enterotoxin B (LTB) of enterotoxigenic Escherichia coli as an oral adjuvant in mice.

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    Yu, M; Qi, R; Chen, C; Yin, J; Ma, S; Shi, W; Wu, Y; Ge, J; Jiang, Y; Tang, L; Xu, Y; Li, Y

    2017-02-01

    The aims of this study were to develop an effective oral vaccine against enterotoxigenic Escherichia coli (ETEC) infection and to design new and more versatile mucosal adjuvants. Genetically engineered Lactobacillus casei strains expressing F4 (K88) fimbrial adhesin FaeG (rLpPG-2-FaeG) and either co-expressing heat-labile enterotoxin A (LTA) subunit with an amino acid mutation associated with reduced virulence (LTAK63) and a heat-labile enterotoxin B (LTB) subunit of E. coli (rLpPG-2-LTAK63-co-LTB) or fused-expressing LTAK63 and LTB (rLpPG-2-LTAK63-fu-LTB) were constructed. The immunogenicity of rLpPG-2-FaeG in conjunction with rLpPG-2-LTAK63-co-LTB or rLpPG-2-LTAK63-fu-LTB as an orally administered mucosal adjuvant in mice was evaluated. Results showed that the levels of FaeG-specific serum IgG and mucosal sIgA, as well as the proliferation of lymphocytes, were significantly higher in mice orally co-administered rLpPG-2-FaeG and rLpPG-2-LTAK63-fu-LTB compared with those administered rLpPG-2-FaeG alone, and were lower than those co-administered rLpPG-2-FaeG and rLpPG-2-LTAK63-co-LTB. Moreover, effective protection was observed after challenge with F4+ ETEC strain CVCC 230 in mice co-administered rLpPG-2-FaeG and rLpPG-2-LTAK63-co-LTB or rLpPG-2-FaeG and rLpPG-2-LTAK63-fu-LTB group compared with those that received rLpPG-2-FaeG alone. rLpPG-2-FaeG showed greater immunogenicity in combination with LTAK63 and LTB as molecular adjuvants. Recombinant Lactobacillus provides a promising platform for the development of vaccines against F4+ ETEC infection. © 2016 The Society for Applied Microbiology.

  8. Influence of Host Interleukin-10 Polymorphisms on Development of Traveler's Diarrhea Due to Heat-Labile Enterotoxin-Producing Escherichia coli in Travelers from the United States Who Are Visiting Mexico▿

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    Flores, Jose; DuPont, Herbert L.; Lee, Stephanie A.; Belkind-Gerson, Jaime; Paredes, Mercedes; Mohamed, Jamal A.; Armitige, Lisa Y.; Guo, Dong-Chuan; Okhuysen, Pablo C.

    2008-01-01

    Up to 60% of U.S. visitors to Mexico develop traveler's diarrhea (TD), mostly due to enterotoxigenic Escherichia coli (ETEC) strains that produce heat-labile (LT) and/or heat-stable (ST) enterotoxins. Distinct single-nucleotide polymorphisms (SNPs) within the interleukin-10 (IL-10) promoter have been associated with high, intermediate, or low production of IL-10. We conducted a prospective study to investigate the association of SNPs in the IL-10 promoter and the occurrence of TD in ETEC LT-exposed travelers. Sera from U.S. travelers to Mexico collected on arrival and departure were studied for ETEC LT seroconversion by using cholera toxin as the antigen. Pyrosequencing was performed to genotype IL-10 SNPs. Stools from subjects who developed diarrhea were also studied for other enteropathogens. One hundred twenty-one of 569 (21.3%) travelers seroconverted to ETEC LT, and among them 75 (62%) developed diarrhea. Symptomatic seroconversion was more commonly seen in subjects who carried a genotype producing high levels of IL-10; it was seen in 83% of subjects with the GG genotype versus 54% of subjects with the AA genotype at IL-10 gene position −1082 (P, 0.02), in 71% of those with the CC genotype versus 33% of those with the TT genotype at position −819 (P, 0.005), and in 71% of those with the CC genotype versus 38% of those with the AA genotype at position −592 (P, 0.02). Travelers with the GCC haplotype were more likely to have symptomatic seroconversion than those with the ATA haplotype (71% versus 38%; P, 0.002). Travelers genetically predisposed to produce high levels of IL-10 were more likely to experience symptomatic ETEC TD. PMID:18579697

  9. Influence of host interleukin-10 polymorphisms on development of traveler's diarrhea due to heat-labile enterotoxin-producing Escherichia coli in travelers from the United States who are visiting Mexico.

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    Flores, Jose; DuPont, Herbert L; Lee, Stephanie A; Belkind-Gerson, Jaime; Paredes, Mercedes; Mohamed, Jamal A; Armitige, Lisa Y; Guo, Dong-Chuan; Okhuysen, Pablo C

    2008-08-01

    Up to 60% of U.S. visitors to Mexico develop traveler's diarrhea (TD), mostly due to enterotoxigenic Escherichia coli (ETEC) strains that produce heat-labile (LT) and/or heat-stable (ST) enterotoxins. Distinct single-nucleotide polymorphisms (SNPs) within the interleukin-10 (IL-10) promoter have been associated with high, intermediate, or low production of IL-10. We conducted a prospective study to investigate the association of SNPs in the IL-10 promoter and the occurrence of TD in ETEC LT-exposed travelers. Sera from U.S. travelers to Mexico collected on arrival and departure were studied for ETEC LT seroconversion by using cholera toxin as the antigen. Pyrosequencing was performed to genotype IL-10 SNPs. Stools from subjects who developed diarrhea were also studied for other enteropathogens. One hundred twenty-one of 569 (21.3%) travelers seroconverted to ETEC LT, and among them 75 (62%) developed diarrhea. Symptomatic seroconversion was more commonly seen in subjects who carried a genotype producing high levels of IL-10; it was seen in 83% of subjects with the GG genotype versus 54% of subjects with the AA genotype at IL-10 gene position -1082 (P, 0.02), in 71% of those with the CC genotype versus 33% of those with the TT genotype at position -819 (P, 0.005), and in 71% of those with the CC genotype versus 38% of those with the AA genotype at position -592 (P, 0.02). Travelers with the GCC haplotype were more likely to have symptomatic seroconversion than those with the ATA haplotype (71% versus 38%; P, 0.002). Travelers genetically predisposed to produce high levels of IL-10 were more likely to experience symptomatic ETEC TD.

  10. Attenuated Escherichia coli strains expressing the colonization factor antigen I (CFA/I) and a detoxified heat-labile enterotoxin (LThK63) enhance clearance of ETEC from the lungs of mice and protect mice from intestinal ETEC colonization and LT-induced fluid accumulation.

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    Byrd, Wyatt; Boedeker, Edgar C

    2013-03-15

    Although enterotoxigenic Escherichia coli (ETEC) infections are important causes of infantile and traveler's diarrhea there is no licensed vaccine available for those at-risk. Our goal is to develop a safe, live attenuated ETEC vaccine. We used an attenuated E. coli strain (O157:H7, Δ-intimin, Stx1-neg, Stx2-neg) as a vector (ZCR533) to prepare two vaccine strains, one strain expressing colonization factor antigen I (ZCR533-CFA/I) and one strain expressing CFA/I and a detoxified heat-labile enterotoxin (ZCR533-CFA/I+LThK63) to deliver ETEC antigens to mucosal sites in BALB/c mice. Following intranasal and intragastric immunization with the vaccine strains, serum IgG and IgA antibodies were measured to the CFA/I antigen, however, only serum IgG antibodies were detected to the heat-labile enterotoxin. Intranasal administration of the vaccine strains induced respiratory and intestinal antibody responses to the CFA/I and LT antigens, while intragastric administration induced only intestinal antibody responses with no respiratory antibodies detected to the CFA/I and LT antigens. Mice immunized intranasally with the vaccine strains showed enhanced clearance of wild-type (wt) ETEC bacteria from the lungs. Mice immunized intranasally and intragastrically with the vaccine strains were protected from intestinal colonization following oral challenge with ETEC wt bacteria. Mice immunized intragastrically with the ZCR533-CFA/I+LThK63 vaccine strain had less fluid accumulate in their intestine following challenge with ETEC wt bacteria or with purified LT as compared to the sham mice indicating that the immunized mice were protected from LT-induced intestinal fluid accumulation. Thus, mice intragastrically immunized with the ZCR533-CFA/I+LThK63 vaccine strain were able to effectively neutralize the activity of the LT enterotoxin. However, no difference in intestinal fluid accumulation was detected in the mice immunized intranasally with the vaccine strain as compared to the sham

  11. Single Chain Variable Fragments Produced in Escherichia coli against Heat-Labile and Heat-Stable Toxins from Enterotoxigenic E. coli.

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    Christiane Y Ozaki

    Full Text Available Diarrhea is a prevalent pathological condition frequently associated to the colonization of the small intestine by enterotoxigenic Escherichia coli (ETEC strains, known to be endemic in developing countries. These strains can produce two enterotoxins associated with the manifestation of clinical symptoms that can be used to detect these pathogens. Although several detection tests have been developed, minimally equipped laboratories are still in need of simple and cost-effective methods. With the aim to contribute to the development of such diagnostic approaches, we describe here two mouse hybridoma-derived single chain fragment variable (scFv that were produced in E. coli against enterotoxins of ETEC strains.Recombinant scFv were developed against ETEC heat-labile toxin (LT and heat-stable toxin (ST, from previously isolated hybridoma clones. This work reports their design, construction, molecular and functional characterization against LT and ST toxins. Both antibody fragments were able to recognize the cell-interacting toxins by immunofluorescence, the purified toxins by ELISA and also LT-, ST- and LT/ST-producing ETEC strains.The developed recombinant scFvs against LT and ST constitute promising starting point for simple and cost-effective ETEC diagnosis.

  12. Alkaline pH Is a signal for optimal production and secretion of the heat labile toxin, LT in enterotoxigenic Escherichia coli (ETEC.

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    Lucia Gonzales

    Full Text Available Enterotoxigenic Escherichia coli (ETEC cause secretory diarrhea in children and travelers to endemic areas. ETEC spreads through the fecal-oral route. After ingestion, ETEC passes through the stomach and duodenum before it colonizes the lower part of the small intestine, exposing bacteria to a wide range of pH and environmental conditions. This study aimed to determine the impact of external pH and activity of the Cyclic AMP receptor protein (CRP on the regulation of production and secretion of heat labile (LT enterotoxin. ETEC strain E2863wt and its isogenic mutant E2863ΔCRP were grown in LBK media buffered to pH 5, 7 and 9. GM1 ELISA, cDNA and cAMP analyses were carried out on bacterial pellet and supernatant samples derived from 3 and 5 hours growth and from overnight cultures. We confirm that CRP is a repressor of LT transcription and production as has been shown before but we show for the first time that CRP is a positive regulator of LT secretion both in vitro and in vivo. LT secretion increased at neutral to alkaline pH compared to acidic pH 5 where secretion was completely inhibited. At pH 9 secretion of LT was optimal resulting in 600 percent increase of secreted LT compared to unbuffered LBK media. This effect was not due to membrane leakage since the bacteria were viable at pH 9. The results indicate that the transition to the alkaline duodenum and/or exposure to high pH close to the epithelium as well as activation of the global transcription factor CRP are signals that induce secretion of the LT toxin in ETEC.

  13. Allele Variants of Enterotoxigenic Escherichia coli Heat-Labile Toxin Are Globally Transmitted and Associated with Colonization Factors

    KAUST Repository

    Joffré, Enrique

    2015-01-15

    Enterotoxigenic Escherichia coli (ETEC) is a significant cause of morbidity and mortality in the developing world. ETEC-mediated diarrhea is orchestrated by heat-labile toxin (LT) and heat-stable toxins (STp and STh), acting in concert with a repertoire of more than 25 colonization factors (CFs). LT, the major virulence factor, induces fluid secretion after delivery of a monomeric ADP-ribosylase (LTA) and its pentameric carrier B subunit (LTB). A study of ETEC isolates from humans in Brazil reported the existence of natural LT variants. In the present study, analysis of predicted amino acid sequences showed that the LT amino acid polymorphisms are associated with a geographically and temporally diverse set of 192 clinical ETEC strains and identified 12 novel LT variants. Twenty distinct LT amino acid variants were observed in the globally distributed strains, and phylogenetic analysis showed these to be associated with different CF profiles. Notably, the most prevalent LT1 allele variants were correlated with major ETEC lineages expressing CS1 + CS3 or CS2 + CS3, and the most prevalent LT2 allele variants were correlated with major ETEC lineages expressing CS5 + CS6 or CFA/I. LTB allele variants generally exhibited more-stringent amino acid sequence conservation (2 substitutions identified) than LTA allele variants (22 substitutions identified). The functional impact of LT1 and LT2 polymorphisms on virulence was investigated by measuring total-toxin production, secretion, and stability using GM1-enzyme-linked immunosorbent assays (GM1-ELISA) and in silico protein modeling. Our data show that LT2 strains produce 5-fold more toxin than LT1 strains (P < 0.001), which may suggest greater virulence potential for this genetic variant. Our data suggest that functionally distinct LT-CF variants with increased fitness have persisted during the evolution of ETEC and have spread globally.

  14. Allele Variants of Enterotoxigenic Escherichia coli Heat-Labile Toxin Are Globally Transmitted and Associated with Colonization Factors

    KAUST Repository

    Joffré , Enrique; von Mentzer, Astrid; Abd El Ghany, Moataz; Oezguen, Numan; Savidge, Tor; Dougan, Gordon; Svennerholm, Ann-Mari; Sjö ling, Å sa

    2015-01-01

    Enterotoxigenic Escherichia coli (ETEC) is a significant cause of morbidity and mortality in the developing world. ETEC-mediated diarrhea is orchestrated by heat-labile toxin (LT) and heat-stable toxins (STp and STh), acting in concert with a repertoire of more than 25 colonization factors (CFs). LT, the major virulence factor, induces fluid secretion after delivery of a monomeric ADP-ribosylase (LTA) and its pentameric carrier B subunit (LTB). A study of ETEC isolates from humans in Brazil reported the existence of natural LT variants. In the present study, analysis of predicted amino acid sequences showed that the LT amino acid polymorphisms are associated with a geographically and temporally diverse set of 192 clinical ETEC strains and identified 12 novel LT variants. Twenty distinct LT amino acid variants were observed in the globally distributed strains, and phylogenetic analysis showed these to be associated with different CF profiles. Notably, the most prevalent LT1 allele variants were correlated with major ETEC lineages expressing CS1 + CS3 or CS2 + CS3, and the most prevalent LT2 allele variants were correlated with major ETEC lineages expressing CS5 + CS6 or CFA/I. LTB allele variants generally exhibited more-stringent amino acid sequence conservation (2 substitutions identified) than LTA allele variants (22 substitutions identified). The functional impact of LT1 and LT2 polymorphisms on virulence was investigated by measuring total-toxin production, secretion, and stability using GM1-enzyme-linked immunosorbent assays (GM1-ELISA) and in silico protein modeling. Our data show that LT2 strains produce 5-fold more toxin than LT1 strains (P < 0.001), which may suggest greater virulence potential for this genetic variant. Our data suggest that functionally distinct LT-CF variants with increased fitness have persisted during the evolution of ETEC and have spread globally.

  15. Toxicity and immunogenicity of Enterotoxigenic Escherichia coli heat-labile and heat-stable toxoid fusion 3xSTa(A14Q-LT(S63K/R192G/L211A in a murine model.

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    Chengxian Zhang

    Full Text Available Diarrhea is the second leading cause of death to young children. Enterotoxigenic Escherichia coli (ETEC are the most common bacteria causing diarrhea. Adhesins and enterotoxins are the virulence determinants in ETEC diarrhea. Adhesins mediate bacterial attachment and colonization, and enterotoxins including heat-labile (LT and heat-stable type Ib toxin (STa disrupt fluid homeostasis in host cells that leads to fluid hyper-secretion and diarrhea. Thus, adhesins and enterotoxins have been primarily targeted in ETEC vaccine development. A recent study reported toxoid fusions with STa toxoid (STa(P13F fused at the N- or C-terminus, or inside the A subunit of LT(R192G elicited neutralizing antitoxin antibodies, and suggested application of toxoid fusions in ETEC vaccine development (Liu et al., Infect. Immun. 79:4002-4009, 2011. In this study, we generated a different STa toxoid (STa(A14Q and a triple-mutant LT toxoid (LT(S63K/R192G/L211A, tmLT, constructed a toxoid fusion (3xSTa(A14Q-tmLT that carried 3 copies of STa(A14Q for further facilitation of anti-STa immunogenicity, and assessed antigen safety and immunogenicity in a murine model to explore its potential for ETEC vaccine development. Mice immunized with this fusion antigen showed no adverse effects, and developed antitoxin antibodies particularly through the IP route. Anti-LT antibodies were detected and were shown neutralizing against CT in vitro. Anti-STa antibodies were also detected in the immunized mice, and serum from the IP immunized mice neutralized STa toxin in vitro. Data from this study indicated that toxoid fusion 3xSTa(A14Q-tmLT is safe and can induce neutralizing antitoxin antibodies, and provided helpful information for vaccine development against ETEC diarrhea.

  16. Molecular Characterization of Enterotoxin-Producing Escherichia coli Collected in 2011-2012, Russia.

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    Nikolay N Kartsev

    Full Text Available Enterotoxin-producing Escherichia coli (ETEC are one of the main causative agents of diarrhea in children especially in developing countries and travel diarrhoea in adults. Pathogenic properties of ETEC associated with their ability to produce a heat-stable (ST and/or heat-labile (LT enterotoxins, as well as adhesins providing bacterial adhesion to intestinal epithelial cells. This study presents the molecular characterization of the ETEC isolates collected from the Central and Far-Eastern regions of Russia in 2011-2012. It was shown that all ETEC under study (n=18 had the heat-labile enterotoxin-coding operon elt, and had no the genes of the heat-stable enterotoxin operon est. DNA sequencing revealed two types of nucleotide exchanges in the eltB gene coding subunit B of LT in isolates collected from Cherepovets city (Central region, Russia and Vladivostok city (Far-East region, Russia. Only one ETEC strain carried genes cfaA, cfaB, cfaC and cfaD coding adhesion factor CFA/I. Expression of LT in four ETEC isolates in the agglutination reaction was detected using a latex test-system. The isolates were assigned to serogroups O142 (n = 6, О6 (n = 4, О25 (n = 5, О26 (n = 2, and O115 (n = 1. Genotyping showed that they belonged to an earlier described sequence-type ST4 (n = 3 as well as to 11 novel sequence-types ST1043, ST1312, ST3697, ST3707, ST3708, ST3709, ST3710, ST3755, ST3756, ST3757 and ST4509. The ETEC isolates displayed different levels of antimicrobial resistance. Eight isolates were resistant to only one drug, three isolates-to two drugs, one isolate-to three drugs, two isolates-to four antibacterials, and only one isolate to each of the five, six and ten antibacterials simultaneously. Genetic determinants of the resistance to beta-lactams and other classes of antibacterials on the ETEC genomes were identified. There are blaTEM (n = 10, blaCTX-M-15 (n = 1, class 1 integron (n = 3 carrying resistance cassettes to aminoglycosides and

  17. Molecular Characterization of Enterotoxin-Producing Escherichia coli Collected in 2011-2012, Russia.

    Science.gov (United States)

    Kartsev, Nikolay N; Fursova, Nadezhda K; Pachkunov, Dmitry M; Bannov, Vasiliy A; Eruslanov, Boris V; Svetoch, Edward A; Dyatlov, Ivan A

    2015-01-01

    Enterotoxin-producing Escherichia coli (ETEC) are one of the main causative agents of diarrhea in children especially in developing countries and travel diarrhoea in adults. Pathogenic properties of ETEC associated with their ability to produce a heat-stable (ST) and/or heat-labile (LT) enterotoxins, as well as adhesins providing bacterial adhesion to intestinal epithelial cells. This study presents the molecular characterization of the ETEC isolates collected from the Central and Far-Eastern regions of Russia in 2011-2012. It was shown that all ETEC under study (n=18) had the heat-labile enterotoxin-coding operon elt, and had no the genes of the heat-stable enterotoxin operon est. DNA sequencing revealed two types of nucleotide exchanges in the eltB gene coding subunit B of LT in isolates collected from Cherepovets city (Central region, Russia) and Vladivostok city (Far-East region, Russia). Only one ETEC strain carried genes cfaA, cfaB, cfaC and cfaD coding adhesion factor CFA/I. Expression of LT in four ETEC isolates in the agglutination reaction was detected using a latex test-system. The isolates were assigned to serogroups O142 (n = 6), О6 (n = 4), О25 (n = 5), О26 (n = 2), and O115 (n = 1). Genotyping showed that they belonged to an earlier described sequence-type ST4 (n = 3) as well as to 11 novel sequence-types ST1043, ST1312, ST3697, ST3707, ST3708, ST3709, ST3710, ST3755, ST3756, ST3757 and ST4509. The ETEC isolates displayed different levels of antimicrobial resistance. Eight isolates were resistant to only one drug, three isolates-to two drugs, one isolate-to three drugs, two isolates-to four antibacterials, and only one isolate to each of the five, six and ten antibacterials simultaneously. Genetic determinants of the resistance to beta-lactams and other classes of antibacterials on the ETEC genomes were identified. There are blaTEM (n = 10), blaCTX-M-15 (n = 1), class 1 integron (n = 3) carrying resistance cassettes to aminoglycosides and

  18. Inhibition of Binding of the AB5-Type Enterotoxins LT-I and Cholera Toxin to Ganglioside GM1 by Galactose-Rich Dietary Components

    NARCIS (Netherlands)

    Becker, P.M.; Widjaja-Greefkes, H.C.A.; Wikselaar, van P.G.

    2010-01-01

    Cholera, travelers' diarrhea, or colibacillosis in pigs can possibly be prevented or attenuated by dietary provision of competitive inhibitors that react with the GM1-binding sites of the enterotoxins cholera toxin (CT), human Escherichia coli heat-labile enterotoxin of serogroup I (LTh-I), and

  19. Rotavirus 2/6 Viruslike Particles Administered Intranasally with Cholera Toxin, Escherichia coli Heat-Labile Toxin (LT), and LT-R192G Induce Protection from Rotavirus Challenge

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    O’Neal, Christine M.; Clements, John D.; Estes, Mary K.; Conner, Margaret E.

    1998-01-01

    We have shown that rotavirus 2/6 viruslike particles composed of proteins VP2 and VP6 (2/6-VLPs) administered to mice intranasally with cholera toxin (CT) induced protection from rotavirus challenge, as measured by virus shedding. Since it is unclear if CT will be approved for human use, we evaluated the adjuvanticity of Escherichia coli heat-labile toxin (LT) and LT-R192G. Mice were inoculated intranasally with 10 μg of 2/6-VLPs combined with CT, LT, or LT-R192G. All three adjuvants induced ...

  20. The detection of K88, K99 fimbrial antigen and enterotoxin genes of Escherichia coli isolated from piglets and calves with diarrhoea in Indonesia

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    Supar

    1996-03-01

    Full Text Available Enterotoxigenic Escherichia coli (ETEC strains cause diarrhoeal disease in piglets and calves in Indonesia. These strains possess two virulence factors namely attachment and enterotoxin antigens . These factors could be detected phenotypically and genetically. Haemolytic Escherichia coli (E coli isolates possessing K88 fimbrial antigen associated with 0-group 108 and 149. They were positive for K88 gene and demonstrated their ability to produce heat labile enterotoxin (LT and genetically were all positive for LT gene . Seventeen isolates ofE coli K88 which associated with 0-group 149 were positive forSTb gene, other O-serotypes were negative . Ten isolates of Ecoli K88 which associated with 0-group 108 possessed K88, K99, LT and STa genes, but negative for STb gene . However, phenotypically the K99 antigen and STa toxin were not expressed under laboratory conditions, the reason was not well understood . E. coli K99 strains isolated from calves wit h diarrhoea were all associated with 0-group 9 and produced STa toxin when tested by suckling mousse bioassay. The E. coli K99 calf isolates were all hybridized with K99 and STa gene only . It is likely that K99 gene is associated with STa gene . The DNA hybridization technique is more convenience to be used for confirmation diagnosis of colibacillosis, however, not all veterinary laboratories could perform these tests .

  1. Rotavirus 2/6 Viruslike Particles Administered Intranasally with Cholera Toxin, Escherichia coli Heat-Labile Toxin (LT), and LT-R192G Induce Protection from Rotavirus Challenge

    Science.gov (United States)

    O’Neal, Christine M.; Clements, John D.; Estes, Mary K.; Conner, Margaret E.

    1998-01-01

    We have shown that rotavirus 2/6 viruslike particles composed of proteins VP2 and VP6 (2/6-VLPs) administered to mice intranasally with cholera toxin (CT) induced protection from rotavirus challenge, as measured by virus shedding. Since it is unclear if CT will be approved for human use, we evaluated the adjuvanticity of Escherichia coli heat-labile toxin (LT) and LT-R192G. Mice were inoculated intranasally with 10 μg of 2/6-VLPs combined with CT, LT, or LT-R192G. All three adjuvants induced equivalent geometric mean titers of rotavirus-specific serum antibody and intestinal immunoglobulin G (IgG). Mice inoculated with 2/6-VLPs with LT produced significantly higher titers of intestinal IgA than mice given CT as the adjuvant. All mice inoculated with 2/6-VLPs mixed with LT and LT-R192G were totally protected (100%) from rotavirus challenge, while mice inoculated with 2/6-VLPs mixed with CT showed a mean 91% protection from challenge. The availability of a safe, effective mucosal adjuvant such as LT-R192G will increase the practicality of administering recombinant vaccines mucosally. PMID:9525668

  2. Genetic fusions of a CFA/I/II/IV MEFA (multiepitope fusion antigen) and a toxoid fusion of heat-stable toxin (STa) and heat-labile toxin (LT) of enterotoxigenic Escherichia coli (ETEC) retain broad anti-CFA and antitoxin antigenicity.

    Science.gov (United States)

    Ruan, Xiaosai; Sack, David A; Zhang, Weiping

    2015-01-01

    Immunological heterogeneity has long been the major challenge in developing broadly effective vaccines to protect humans and animals against bacterial and viral infections. Enterotoxigenic Escherichia coli (ETEC) strains, the leading bacterial cause of diarrhea in humans, express at least 23 immunologically different colonization factor antigens (CFAs) and two distinct enterotoxins [heat-labile toxin (LT) and heat-stable toxin type Ib (STa or hSTa)]. ETEC strains expressing any one or two CFAs and either toxin cause diarrhea, therefore vaccines inducing broad immunity against a majority of CFAs, if not all, and both toxins are expected to be effective against ETEC. In this study, we applied the multiepitope fusion antigen (MEFA) strategy to construct ETEC antigens and examined antigens for broad anti-CFA and antitoxin immunogenicity. CFA MEFA CFA/I/II/IV [CVI 2014, 21(2):243-9], which carried epitopes of seven CFAs [CFA/I, CFA/II (CS1, CS2, CS3), CFA/IV (CS4, CS5, CS6)] expressed by the most prevalent and virulent ETEC strains, was genetically fused to LT-STa toxoid fusion monomer 3xSTaA14Q-dmLT or 3xSTaN12S-dmLT [IAI 2014, 82(5):1823-32] for CFA/I/II/IV-STaA14Q-dmLT and CFA/I/II/IV-STaN12S-dmLT MEFAs. Mice intraperitoneally immunized with either CFA/I/II/IV-STa-toxoid-dmLT MEFA developed antibodies specific to seven CFAs and both toxins, at levels equivalent or comparable to those induced from co-administration of the CFA/I/II/IV MEFA and toxoid fusion 3xSTaN12S-dmLT. Moreover, induced antibodies showed in vitro adherence inhibition activities against ETEC or E. coli strains expressing these seven CFAs and neutralization activities against both toxins. These results indicated CFA/I/II/IV-STa-toxoid-dmLT MEFA or CFA/I/II/IV MEFA combined with 3xSTaN12S-dmLT induced broadly protective anti-CFA and antitoxin immunity, and suggested their potential application in broadly effective ETEC vaccine development. This MEFA strategy may be generally used in multivalent

  3. Genetic fusions of a CFA/I/II/IV MEFA (multiepitope fusion antigen and a toxoid fusion of heat-stable toxin (STa and heat-labile toxin (LT of enterotoxigenic Escherichia coli (ETEC retain broad anti-CFA and antitoxin antigenicity.

    Directory of Open Access Journals (Sweden)

    Xiaosai Ruan

    Full Text Available Immunological heterogeneity has long been the major challenge in developing broadly effective vaccines to protect humans and animals against bacterial and viral infections. Enterotoxigenic Escherichia coli (ETEC strains, the leading bacterial cause of diarrhea in humans, express at least 23 immunologically different colonization factor antigens (CFAs and two distinct enterotoxins [heat-labile toxin (LT and heat-stable toxin type Ib (STa or hSTa]. ETEC strains expressing any one or two CFAs and either toxin cause diarrhea, therefore vaccines inducing broad immunity against a majority of CFAs, if not all, and both toxins are expected to be effective against ETEC. In this study, we applied the multiepitope fusion antigen (MEFA strategy to construct ETEC antigens and examined antigens for broad anti-CFA and antitoxin immunogenicity. CFA MEFA CFA/I/II/IV [CVI 2014, 21(2:243-9], which carried epitopes of seven CFAs [CFA/I, CFA/II (CS1, CS2, CS3, CFA/IV (CS4, CS5, CS6] expressed by the most prevalent and virulent ETEC strains, was genetically fused to LT-STa toxoid fusion monomer 3xSTaA14Q-dmLT or 3xSTaN12S-dmLT [IAI 2014, 82(5:1823-32] for CFA/I/II/IV-STaA14Q-dmLT and CFA/I/II/IV-STaN12S-dmLT MEFAs. Mice intraperitoneally immunized with either CFA/I/II/IV-STa-toxoid-dmLT MEFA developed antibodies specific to seven CFAs and both toxins, at levels equivalent or comparable to those induced from co-administration of the CFA/I/II/IV MEFA and toxoid fusion 3xSTaN12S-dmLT. Moreover, induced antibodies showed in vitro adherence inhibition activities against ETEC or E. coli strains expressing these seven CFAs and neutralization activities against both toxins. These results indicated CFA/I/II/IV-STa-toxoid-dmLT MEFA or CFA/I/II/IV MEFA combined with 3xSTaN12S-dmLT induced broadly protective anti-CFA and antitoxin immunity, and suggested their potential application in broadly effective ETEC vaccine development. This MEFA strategy may be generally used in

  4. Use of inactivated E.Coli enterotoxins to enhance respiratory mucosal adjuvanticity during vaccination in swine

    Science.gov (United States)

    In order to augment responses to respiratory vaccines in swine, various adjuvants were intranasally co-administered with an antigen to pigs. Detoxified E. coli enterotoxins LTK63 and LTR72 enhanced mucosal and systemic immunity to the model peptide, exhibiting their efficacy as mucosal adjuvants for...

  5. Intranasal Administration of 2/6-Rotavirus-Like Particles with Mutant Escherichia coli Heat-Labile Toxin (LT-R192G) Induces Antibody-Secreting Cell Responses but Not Protective Immunity in Gnotobiotic Pigs

    Science.gov (United States)

    Yuan, Lijuan; Geyer, Annelise; Hodgins, Douglas C.; Fan, Zhiqian; Qian, Yuan; Chang, Kyeong-Ok; Crawford, Sue E.; Parreño, Viviana; Ward, Lucy A.; Estes, Mary K.; Conner, Margaret E.; Saif, Linda J.

    2000-01-01

    We investigated the immunogenicity of recombinant double-layered rotavirus-like particle (2/6-VLPs) vaccines derived from simian SA11 or human (VP6) Wa and bovine RF (VP2) rotavirus strains. The 2/6-VLPs were administered to gnotobiotic pigs intranasally (i.n.) with a mutant Escherichia coli heat-labile toxin, LT-R192G (mLT), as mucosal adjuvant. Pigs were challenged with virulent Wa (P1A[8],G1) human rotavirus at postinoculation day (PID) 21 (two-dose VLP regimen) or 28 (three-dose VLP regimen). In vivo antigen-activated antibody-secreting cells (ASC) (effector B cells) and in vitro antigen-reactivated ASC (derived from memory B cells) from intestinal and systemic lymphoid tissues (duodenum, ileum, mesenteric lymph nodes [MLN], spleen, peripheral blood lymphocytes [PBL], and bone marrow lymphocytes) collected at selected times were quantitated by enzyme-linked immunospot assays. Rotavirus-specific immunoglobulin M (IgM), IgA, and IgG ASC and memory B-cell responses were detected by PID 21 or 28 in intestinal and systemic lymphoid tissues after i.n. inoculation with two or three doses of 2/6-VLPs with or without mLT. Greater mean numbers of virus-specific ASC and memory B cells in all tissues prechallenge were induced in pigs inoculated with two doses of SA11 2/6-VLPs plus mLT compared to SA11 2/6-VLPs without mLT. After challenge, anamnestic IgA and IgG ASC and memory B-cell responses were detected in intestinal lymphoid tissues of all VLP-inoculated groups, but serum virus-neutralizing antibody titers were not significantly enhanced compared to the challenged controls. Pigs inoculated with Wa-RF 2/6-VLPs (with or without mLT) developed higher anamnestic IgA and IgG ASC responses in ileum after challenge compared to pigs inoculated with SA11 2/6-VLPs (with or without mLT). Three doses of SA 11 2/6-VLP plus mLT induced the highest mean numbers of IgG memory B cells in MLN, spleen, and PBL among all groups postchallenge. However, no significant protection against

  6. Receptors and cGMP signalling mechanism for E. coli enterotoxin in opossum kidney

    International Nuclear Information System (INIS)

    Forte, L.R.; Krause, W.J.; Freeman, R.H.

    1988-01-01

    Receptors for the heat-stable enterotoxin produced by Escherichia coli were found in the kidney and intestine of the North American opossum and in cultured renal cell lines. The enterotoxin markedly increased guanosine 3',5'-cyclic monophosphate (cGMP) production in slices of kidney cortex and medulla, in suspensions of intestinal mucosa, and in the opossum kidney (OK) and rat kangaroo kidney (PtK-2) cell lines. In contrast, atrial natriuretic factor elicited much smaller increases in cGMP levels of kidney, intestine, or cultured kidney cell lines. The enterotoxin receptors in OK cells had a molecular mass of approximately 120 kDa when measured by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of receptors crosslinked with 125 I-enterotoxin. The occurrence of receptors for the E. coli peptide in OK implies that these receptors may be involved in the regulation of renal tubular function in the opossum. E. coli enterotoxin caused a much larger increase in urine cGMP excretion than did atrial natriuretic factor when these peptides were injected intravenously into opossums. However, atrial natriuretic factor elicited a marked diuresis, natriuresis, and increased urinary excretion of calcium, phosphate, potassium, and magnesium. In contrast, the enterotoxin did not acutely influence OK fluid and electrolyte excretion. Thus the substantial increase in cGMP synthesis produced by the bacterial peptide in OK cortex and medulla in vitro and the increased renal excretion of cGMP in vivo were not associated with changes in electrolyte or water excretion. Whether cGMP represents a second messenger molecule in the kidney is an interesting question that was raised but not answered in this series of experiments

  7. Safety and efficacy of E coli enterotoxin adjuvant for urease-based rectal immunization against Helicobacter pylori.

    Science.gov (United States)

    Sougioultzis, Stavros; Lee, Cynthia K; Alsahli, Mazen; Banerjee, Subhas; Cadoz, Michel; Schrader, Robert; Guy, Bruno; Bedford, Philip; Monath, Thomas P; Kelly, Ciaran P; Michetti, Pierre

    2002-12-13

    Low dose E. coli heat-labile enterotoxin (LT), delivered orally or enterically, has been used as an adjuvant for Helicobacter pylori (H. pylori) urease in healthy adults. In this study we aim to test the safety and adjuvant efficacy of LT delivered rectally together with recombinant H. pylori urease. Eighteen healthy adults without present or past H. pylori infection were enrolled in a double blind, randomized, ascending dose study to receive either urease (60 mg), or urease (60 mg) + LT (5 or 25 microg). The immunization preparation was administered per rectum on days 0, 14 and 28. Serum, stool and saliva anti-urease and anti-LT IgG and IgA antibodies (Abs) were measured and urease-specific and LT-specific antigen secreting cells (ASCs) were counted in peripheral blood at baseline and 7 (ASC counts) or 14 days (antibody levels) after each dosing. Peripheral blood lymphoproliferation assays were also performed at baseline and at the end of the study. Rectally delivered urease and LT were well tolerated. Among the 12 subjects assigned to urease+LT, 2 (16.7%) developed anti-urease IgG Abs, 1 (8.3%) developed anti-urease IgA Abs, and 3 (25%) showed urease-specific IgA(+) ASCs. Immune responses to LT were more vigorous, especially in subjects exposed to 5 microg LT. In the urease+ 5 microg LT group, anti-LT IgG and IgA Abs developed in 60 and 80% of the subjects, respectively, while LT-specific IgG(+) and IgA(+) ASCs were detected in all subjects. The magnitude of the anti-LT response was much higher than the response to urease. No IgA anti-urease or anti-LT Abs were detected in stool or saliva and lymphocyte proliferative responses to urease were unsatisfactory. In conclusion, rectal delivery of 5 microg LT is safe and induces vigorous systemic anti-LT immune responses. Further studies are needed to determine if LT can be an effective adjuvant for rectally delivered antigens.

  8. Association and dissociation of Escherichia coli heat-stable enterotoxin from rat brush border membrane receptors

    International Nuclear Information System (INIS)

    Cohen, M.B.; Thompson, M.R.; Overmann, G.J.; Giannella, R.A.

    1987-01-01

    Escherichia coli heat-stable enterotoxin (ST) binds to receptors on rat intestinal cells and brush border membranes (BBM). We devised experiments to examine the reversibility of ST binding. We found that both 125 I-labeled ST and native ST were spontaneously dissociable from the BBM receptor. Radiolabeled ST bound to BBM was also dissociated by the addition of avid goat anti-ST antiserum. Furthermore, using a computer program for analysis of ligand binding, we calculated an apparent Ka of 10(8) liters/mol from competitive inhibition and saturation-binding data. This is significantly lower than the value previously reported by others. Our findings, of a lower Ka and a reversible ST-binding process, suggest that a therapeutic strategy of removing bound ST from its receptor or competing with the enterocyte receptor for unbound ST might be successful in terminating ST-induced secretion

  9. Development and accuracy of quantitative real-time polymerase chain reaction assays for detection and quantification of enterotoxigenic Escherichia coli (ETEC) heat labile and heat stable toxin genes in travelers' diarrhea samples.

    Science.gov (United States)

    Youmans, Bonnie P; Ajami, Nadim J; Jiang, Zhi-Dong; Petrosino, Joseph F; DuPont, Herbert L; Highlander, Sarah K

    2014-01-01

    Enterotoxigenic Escherichia coli (ETEC), the leading bacterial pathogen of travelers' diarrhea, is routinely detected by an established DNA hybridization protocol that is neither sensitive nor quantitative. Quantitative real-time polymerase chain reaction (qPCR) assays that detect the ETEC toxin genes eltA, sta1, and sta2 in clinical stool samples were developed and tested using donor stool inoculated with known quantities of ETEC bacteria. The sensitivity of the qPCR assays is 89%, compared with 22% for the DNA hybridization assay, and the limits of detection are 10,000-fold lower than the DNA hybridization assays performed in parallel. Ninety-three clinical stool samples, previously characterized by DNA hybridization, were tested using the new ETEC qPCR assays. Discordant toxin profiles were observed for 22 samples, notably, four samples originally typed as ETEC negative were ETEC positive. The qPCR assays are unique in their sensitivity and ability to quantify the three toxin genes in clinical stool samples.

  10. ANIMAL ENTEROTOXIGENIC ESCHERICHIA COLI

    Science.gov (United States)

    Dubreuil, J. Daniel; Isaacson, Richard E.; Schifferli, Dieter M.

    2016-01-01

    Enterotoxigenic Escherichia coli (ETEC) is the most common cause of E. coli diarrhea in farm animals. ETEC are characterized by the ability to produce two types of virulence factors; adhesins that promote binding to specific enterocyte receptors for intestinal colonization and enterotoxins responsible for fluid secretion. The best-characterized adhesins are expressed in the context of fimbriae, such as the F4 (also designated K88), F5 (K99), F6 (987P), F17 and F18 fimbriae. Once established in the animal small intestine, ETEC produces enterotoxin(s) that lead to diarrhea. The enterotoxins belong to two major classes; heat-labile toxin that consist of one active and five binding subunits (LT), and heat-stable toxins that are small polypeptides (STa, STb, and EAST1). This chapter describes the disease and pathogenesis of animal ETEC, the corresponding virulence genes and protein products of these bacteria, their regulation and targets in animal hosts, as well as mechanisms of action. Furthermore, vaccines, inhibitors, probiotics and the identification of potential new targets identified by genomics are presented in the context of animal ETEC. PMID:27735786

  11. From Escherichia coli heat-stable enterotoxin to mammalian endogenous guanylin hormones

    International Nuclear Information System (INIS)

    Lima, A.A.M.; Fonteles, M.C.

    2014-01-01

    The isolation of heat-stable enterotoxin (STa) from Escherichia coli and cholera toxin from Vibrio cholerae has increased our knowledge of specific mechanisms of action that could be used as pharmacological tools to understand the guanylyl cyclase-C and the adenylyl cyclase enzymatic systems. These discoveries have also been instrumental in increasing our understanding of the basic mechanisms that control the electrolyte and water balance in the gut, kidney, and urinary tracts under normal conditions and in disease. Herein, we review the evolution of genes of the guanylin family and STa genes from bacteria to fish and mammals. We also describe new developments and perspectives regarding these novel bacterial compounds and peptide hormones that act in electrolyte and water balance. The available data point toward new therapeutic perspectives for pathological features such as functional gastrointestinal disorders associated with constipation, colorectal cancer, cystic fibrosis, asthma, hypertension, gastrointestinal barrier function damage associated with enteropathy, enteric infection, malnutrition, satiety, food preferences, obesity, metabolic syndrome, and effects on behavior and brain disorders such as attention deficit, hyperactivity disorder, and schizophrenia

  12. From Escherichia coli heat-stable enterotoxin to mammalian endogenous guanylin hormones

    Energy Technology Data Exchange (ETDEWEB)

    Lima, A.A.M. [Universidade Federal do Ceará, Departamento de Fisiologia e Farmacologia, Escola de Medicina, Instituto de Biomedicina, Unidade de Pesquisas Clínicas, Fortaleza, CE, Brasil, Unidade de Pesquisas Clínicas, Instituto de Biomedicina, Departamento de Fisiologia e Farmacologia, Escola de Medicina, Universidade Federal do Ceará, Fortaleza, CE (Brazil); Fonteles, M.C. [Universidade Federal do Ceará, Departamento de Fisiologia e Farmacologia, Escola de Medicina, Instituto de Biomedicina, Unidade de Pesquisas Clínicas, Fortaleza, CE, Brasil, Unidade de Pesquisas Clínicas, Instituto de Biomedicina, Departamento de Fisiologia e Farmacologia, Escola de Medicina, Universidade Federal do Ceará, Fortaleza, CE (Brazil); Universidade Estadual do Ceará, Instituto de Ciências Biomédicas, Fortaleza, CE, Brasil, Instituto de Ciências Biomédicas, Universidade Estadual do Ceará, Fortaleza, CE (Brazil)

    2014-03-03

    The isolation of heat-stable enterotoxin (STa) from Escherichia coli and cholera toxin from Vibrio cholerae has increased our knowledge of specific mechanisms of action that could be used as pharmacological tools to understand the guanylyl cyclase-C and the adenylyl cyclase enzymatic systems. These discoveries have also been instrumental in increasing our understanding of the basic mechanisms that control the electrolyte and water balance in the gut, kidney, and urinary tracts under normal conditions and in disease. Herein, we review the evolution of genes of the guanylin family and STa genes from bacteria to fish and mammals. We also describe new developments and perspectives regarding these novel bacterial compounds and peptide hormones that act in electrolyte and water balance. The available data point toward new therapeutic perspectives for pathological features such as functional gastrointestinal disorders associated with constipation, colorectal cancer, cystic fibrosis, asthma, hypertension, gastrointestinal barrier function damage associated with enteropathy, enteric infection, malnutrition, satiety, food preferences, obesity, metabolic syndrome, and effects on behavior and brain disorders such as attention deficit, hyperactivity disorder, and schizophrenia.

  13. Lactobacillus zeae protects Caenorhabditis elegans from enterotoxigenic Escherichia coli-caused death by inhibiting enterotoxin gene expression of the pathogen.

    Directory of Open Access Journals (Sweden)

    Mengzhou Zhou

    Full Text Available BACKGROUND: The nematode Caenorhabditis elegans has become increasingly used for screening antimicrobials and probiotics for pathogen control. It also provides a useful tool for studying microbe-host interactions. This study has established a C. elegans life-span assay to preselect probiotic bacteria for controlling K88(+ enterotoxigenic Escherichia coli (ETEC, a pathogen causing pig diarrhea, and has determined a potential mechanism underlying the protection provided by Lactobacillus. METHODOLOGY/PRINCIPAL FINDINGS: Life-span of C. elegans was used to measure the response of worms to ETEC infection and protection provided by lactic acid-producing bacteria (LAB. Among 13 LAB isolates that varied in their ability to protect C. elegans from death induced by ETEC strain JG280, Lactobacillus zeae LB1 offered the highest level of protection (86%. The treatment with Lactobacillus did not reduce ETEC JG280 colonization in the nematode intestine. Feeding E. coli strain JFF4 (K88(+ but lacking enterotoxin genes of estA, estB, and elt did not cause death of worms. There was a significant increase in gene expression of estA, estB, and elt during ETEC JG280 infection, which was remarkably inhibited by isolate LB1. The clone with either estA or estB expressed in E. coli DH5α was as effective as ETEC JG280 in killing the nematode. However, the elt clone killed only approximately 40% of worms. The killing by the clones could also be prevented by isolate LB1. The same isolate only partially inhibited the gene expression of enterotoxins in both ETEC JG280 and E. coli DH5α in-vitro. CONCLUSIONS/SIGNIFICANCE: The established life-span assay can be used for studies of probiotics to control ETEC (for effective selection and mechanistic studies. Heat-stable enterotoxins appeared to be the main factors responsible for the death of C. elegans. Inhibition of ETEC enterotoxin production, rather than interference of its intestinal colonization, appears to be the

  14. Cloning in Escherichia coli of the enterotoxin gene from Clostridium perfringens type A.

    Science.gov (United States)

    Iwanejko, L A; Routledge, M N; Stewart, G S

    1989-04-01

    A 26 bp DNA probe has been constructed with minimal degeneracy to the protein sequence for Clostridium perfringens enterotoxin. The probe has been hybridized against a 6-10 kb chromosomal bank from C. perfringens 8239, prepared as a HindIII partial digest in pHG165. From this survey a clone has been identified containing a 6.8 kb DNA insert with strong hybridization to the probe. Direct plasmid sequencing has identified a translational reading frame within this clone which correlates with the known protein sequence for the type A enterotoxin. DNA sequences 5' to this open reading frame and containing the putative transcriptional control regions show areas of significant homology with regions upstream from the ATG codon of the tetanus toxin gene.

  15. Estrogen inhibits chloride secretion caused by cholera and Escherichia coli enterotoxins in female rat distal colon.

    LENUS (Irish Health Repository)

    Alzamora, Rodrigo

    2011-05-08

    Excessive Cl(-) secretion is the driving force for secretory diarrhea. 17β-Estradiol has been shown to inhibit Cl(-) secretion in rat distal colon through a nongenomic pathway. We examined whether 17β-estradiol inhibits Cl(-) secretion in an animal model of secretory diarrhea and the downstream effectors involved. The effect of 17β-estradiol on cholera toxin and heat-stable enterotoxin induced Cl(-) secretion in rat colonic mucosal sheets was studied by current-voltage clamping. Selective permeabilization of apical or basolateral membranes with amphotericin B or nystatin was used to isolate basolateral K(+) channel and apical Cl(-) channel activity, respectively. 17β-Estradiol dose-dependently inhibited secretory responses to both toxins with IC(50) values of approximately 1nM. This effect was female-gender specific, with no inhibition observed in male tissues. 17β-Estradiol responses were insensitive to the pure anti-estrogen ICI 182,720. 17β-Estradiol exerted its effects downstream of enterotoxin-induced production of second messengers (cAMP and cGMP) but was dependent on PKCδ activation. In nystatin-permeabilized tissues, apical Cl(-) currents were unaffected by 17β-estradiol treatment while basolateral K(+) current was profoundly inhibited by the hormone. This current was sensitive to the specific KCNQ1 channel inhibitors chromanol 293B and HMR-1556. In conclusion, 17β-estradiol inhibits enterotoxin-induced Cl(-) secretion via a PKCδ-dependent mechanism involving inhibition of basolateral KCNQ1 channels. These data elucidate mechanisms of 17β-estradiol inhibition of Cl(-) secretion induced by enterotoxins in intestinal epithelia, which may be relevant for the treatment of diarrheal diseases.

  16. Estrogen inhibits chloride secretion caused by cholera and Escherichia coli enterotoxins in female rat distal colon.

    LENUS (Irish Health Repository)

    Alzamora, Rodrigo

    2012-02-01

    Excessive Cl(-) secretion is the driving force for secretory diarrhea. 17beta-Estradiol has been shown to inhibit Cl(-) secretion in rat distal colon through a nongenomic pathway. We examined whether 17beta-estradiol inhibits Cl(-) secretion in an animal model of secretory diarrhea and the downstream effectors involved. The effect of 17beta-estradiol on cholera toxin and heat-stable enterotoxin induced Cl(-) secretion in rat colonic mucosal sheets was studied by current-voltage clamping. Selective permeabilization of apical or basolateral membranes with amphotericin B or nystatin was used to isolate basolateral K(+) channel and apical Cl(-) channel activity, respectively. 17beta-Estradiol dose-dependently inhibited secretory responses to both toxins with IC(50) values of approximately 1nM. This effect was female-gender specific, with no inhibition observed in male tissues. 17beta-Estradiol responses were insensitive to the pure anti-estrogen ICI 182,720. 17beta-Estradiol exerted its effects downstream of enterotoxin-induced production of second messengers (cAMP and cGMP) but was dependent on PKCdelta activation. In nystatin-permeabilized tissues, apical Cl(-) currents were unaffected by 17beta-estradiol treatment while basolateral K(+) current was profoundly inhibited by the hormone. This current was sensitive to the specific KCNQ1 channel inhibitors chromanol 293B and HMR-1556. In conclusion, 17beta-estradiol inhibits enterotoxin-induced Cl(-) secretion via a PKCdelta-dependent mechanism involving inhibition of basolateral KCNQ1 channels. These data elucidate mechanisms of 17beta-estradiol inhibition of Cl(-) secretion induced by enterotoxins in intestinal epithelia, which may be relevant for the treatment of diarrheal diseases.

  17. Estrogen inhibits chloride secretion caused by cholera and Escherichia coli enterotoxins in female rat distal colon.

    OpenAIRE

    Alzamora, Rodrigo; O'Mahony, Fiona; Harvey, Brian J

    2011-01-01

    Excessive Cl(-) secretion is the driving force for secretory diarrhea. 17β-Estradiol has been shown to inhibit Cl(-) secretion in rat distal colon through a nongenomic pathway. We examined whether 17β-estradiol inhibits Cl(-) secretion in an animal model of secretory diarrhea and the downstream effectors involved. The effect of 17β-estradiol on cholera toxin and heat-stable enterotoxin induced Cl(-) secretion in rat colonic mucosal sheets was studied by current-voltage clamping. Selective per...

  18. Prolonged protection against Intranasal challenge with influenza virus following systemic immunization or combinations of mucosal and systemic immunizations with a heat-labile toxin mutant.

    Science.gov (United States)

    Zhou, Fengmin; Goodsell, Amanda; Uematsu, Yasushi; Vajdy, Michael

    2009-04-01

    Seasonal influenza virus infections cause considerable morbidity and mortality in the world, and there is a serious threat of a pandemic influenza with the potential to cause millions of deaths. Therefore, practical influenza vaccines and vaccination strategies that can confer protection against intranasal infection with influenza viruses are needed. In this study, we demonstrate that using LTK63, a nontoxic mutant of the heat-labile toxin from Escherichia coli, as an adjuvant for both mucosal and systemic immunizations, systemic (intramuscular) immunization or combinations of mucosal (intranasal) and intramuscular immunizations protected mice against intranasal challenge with a lethal dose of live influenza virus at 3.5 months after the second immunization.

  19. An Enterotoxin-Like Binary Protein from Pseudomonas protegens with Potent Nematicidal Activity.

    Science.gov (United States)

    Wei, Jun-Zhi; Siehl, Daniel L; Hou, Zhenglin; Rosen, Barbara; Oral, Jarred; Taylor, Christopher G; Wu, Gusui

    2017-10-01

    Soil microbes are a major food source for free-living soil nematodes. It is known that certain soil bacteria have evolved systems to combat predation. We identified the nematode-antagonistic Pseudomonas protegens strain 15G2 from screening of microbes. Through protein purification we identified a binary protein, designated Pp-ANP, which is responsible for the nematicidal activity. This binary protein inhibits Caenorhabditis elegans growth and development by arresting larvae at the L1 stage and killing older-staged worms. The two subunits, Pp-ANP1a and Pp-ANP2a, are active when reconstituted from separate expression in Escherichia coli The binary toxin also shows strong nematicidal activity against three other free-living nematodes ( Pristionchus pacificus , Panagrellus redivivus , and Acrobeloides sp.), but we did not find any activity against insects and fungi under test conditions, indicating specificity for nematodes. Pp-ANP1a has no significant identity to any known proteins, while Pp-ANP2a shows ∼30% identity to E. coli heat-labile enterotoxin (LT) subunit A and cholera toxin (CT) subunit A. Protein modeling indicates that Pp-ANP2a is structurally similar to CT/LT and likely acts as an ADP-ribosyltransferase. Despite the similarity, Pp-ANP shows several characteristics distinct from CT/LT toxins. Our results indicate that Pp-ANP is a new enterotoxin-like binary toxin with potent and specific activity to nematodes. The potency and specificity of Pp-ANP suggest applications in controlling parasitic nematodes and open an avenue for further research on its mechanism of action and role in bacterium-nematode interaction. IMPORTANCE This study reports the discovery of a new enterotoxin-like binary protein, Pp-ANP, from a Pseudomonas protegens strain. Pp-ANP shows strong nematicidal activity against Caenorhabditis elegans larvae and older-staged worms. It also shows strong activity on other free-living nematodes ( Pristionchus pacificus , Panagrellus redivivus , and

  20. PCR detection and serotyping of enterotoxigenic and shigatoxigenic Escherichia coli isolates obtained from chicken meat in Mumbai, India

    Directory of Open Access Journals (Sweden)

    R. J. Zende,

    2013-08-01

    Full Text Available Aim: Present study was undertaken to find out the frequency of few virulent genes and prevalence of related strains of Escherichia coli isolated from chicken meat obtained from chicken retail shops by Polymerase Chain Reaction (PCR.Materials and Methods: 66 samples of freshly slaughtered chicken meat were collected from 22 identified retail shops located at Mumbai city, randomly. Processed meat samples were cultured in EMB agar and presumptive colonies were confirmed by various biochemical tests. PCR method was accustomed for identification of the genes coding for heat-stable enterotoxin a (STa, heat labile enterotoxin (LT, shiga-like toxins 1 and 2 (SLT1 and SLT2. E. coli isolates were sent to National Salmonella and Escherichia Centre, CRI, Kasauli, HP, India for serotyping.Results: 11 (16.67% E. coli strains were isolated from 66 chicken meat samples. 3 (27.27% out of 11 harbored the gene for SLT2, and 2 (18.18% for STa. None of the strain contains SLT1 and LT genes. Serotypes detected were rough, O2, O20, O22, O102 each for one isolate and 6 isolates were untypable (UT.Conclusion: The results concluded that chicken meat samples analysed harbored genes for shiga like toxins and enterotoxins and different serotypes of E. coli. These findings indicating that regular monitoring of chicken meat is essential for this pathogen to prevent potential public health problems.

  1. Involvement of protein kinase C in the mechanism of action of Escherichia coli heat-stable enterotoxin (STa) in a human colonic carcinoma cell line, COLO-205

    International Nuclear Information System (INIS)

    Gupta, Dyuti Datta; Saha, Subhrajit; Chakrabarti, Manoj K.

    2005-01-01

    The present study was undertaken to determine the involvement of calcium-protein kinase C pathway in the mechanism of action of Escherichia coli heat stable enterotoxin (STa) apart from STa-induced activation of guanylate cyclase in human colonic carcinoma cell line COLO-205, which was used as a model cultured cell line to study the mechanism of action of E. coli STa. In response to E. coli STa, protein kinase C (PKC) activity was increased in a time-dependent manner with its physical translocation from cytosol to membrane. Inhibition of the PKC activity in membrane fraction and inhibition of its physical translocation in response to IP 3 -mediated calcium release inhibitor dantrolene suggested the involvement of intracellular store depletion in the regulation of PKC activity. Among different PKC isoforms, predominant involvement of calcium-dependent protein kinase C (PKCα) was specified using isotype-specific pseudosubstrate, which showed pronounce enzyme activity. Inhibition of enzyme activity by PKCα-specific inhibitor Goe6976 and immunoblott study employing isotype-specific antibody further demonstrated the involvement of calcium-dependent isoform of PKC in the mechanism of action of E. coli STa. Moreover, inhibition of guanylate cyclase activity by PKCα-specific inhibitor Goe6976 suggested the involvement of PKCα in the regulation of guanylate cyclase activity

  2. Automated 5 ' nuclease assay for detection of virulence factors in porcine Escherichia coli

    DEFF Research Database (Denmark)

    Frydendahl, K.; Imberechts, H.; Lehmann, S.

    2001-01-01

    (STa, STb, EAST1) and heat labile LT) enterotoxins and the verocytotoxin variant 2e (VT2e). To correctly identify false negative results, an endogenous internal control targeting the E. coil 16S rRNA gene was incorporated in each test tube. The assay was evaluated using a collection of E. coil...... reference strains which have previously been examined with phenotypical assays or DNA hybridization. Furthermore, the assay was evaluated by testing porcine E. coil field strains, previously characterized. The 5' nuclease assay correctly detected the presence of virulence genes in all reference strains....... When testing field strains there was generally excellent agreement with results obtained by laboratories in Belgium and Germany. In conclusion, the 5' nuclease assay developed is a fast and specific tool for detection of E. coli virulence genes in the veterinary diagnostic laboratory....

  3. Evaluation of the adjuvant effect of Escherichia coli heat-labile ...

    African Journals Online (AJOL)

    Data on IgG antibody isotype profiles showed that IgG 1 and IgG 2a were predominant in mice immunized with rMVNP + LT or LTK63 whereas IgG 1 predominated when rMVNP was given on its own implying that LT and LTK63 induce both Th1 and Th2-type immune responses. These results highlight the great potential of ...

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

    Science.gov (United States)

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

    2015-01-01

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

  5. Induction of heat-labile sites in DNA of mammalian cells by the antitumor alkylating drug CC-1065

    International Nuclear Information System (INIS)

    Zsido, T.J.; Woynarowski, J.M.; Baker, R.M.; Gawron, L.S.; Beerman, T.A.

    1991-01-01

    CC-1065 is a very potent antitumor antibiotic capable of covalent and noncovalent binding to the minor groove of naked DNA. Upon thermal treatment, covalent adducts formed between CC-1065 and DNA generate strand break. The authors have shown that this molecular damage can be detected following CC-1065 treatment of mammalian whole cells. Using alkaline sucrose gradient analysis, They observe thermally induced breakage of [ 14 C]thymidine-prelabeled DNA from drug-treated African green monkey kidney BSC-1 cells. Very little damage to cellular DNA by CC-1065 can be detected without first heating the drug-treated samples. CC-1065 can also generate heat-labile sites within DNA during cell lysis and heating, subsequent to the exposure of cells to drug, suggesting that a pool of free and noncovalently bound drug is available for posttreatment adduct formation. This effect was controlled for by mixing [ 3 H]thymidine-labeled untreated cells with the [ 14 C]thymidine-labeled drug-treated samples. The lowest drug dose at which heat-labile sites were detected was 3 nM CC-1065 (3 single-stranded breaks/10 6 base pairs). This concentration reduced survival of BSC-1 cells to 0.1% in cytotoxicity assays. The generation of CC-1065-induced lesions in cellular DNA is time dependent (the frequency of lesions caused by a 60 nM treatment reaching a plateau at 2 h) and is not readily reversible. The results of this study demonstrate that CC-1065 does generate heat-labile sites with the cellular DNA of intact cells and suggest that a mechanism of cytotoxic action of CC-1065 involves formation of covalent adducts to DNA

  6. Molecular characterization and antibiotic resistance of enterotoxigenic and entero-aggregative Escherichia coli isolated from raw milk and unpasteurized cheeses

    Directory of Open Access Journals (Sweden)

    Mojtaba Bonyadian

    2014-04-01

    Full Text Available The aim of this study was to determine the occurrence of enterotoxigenic and enteroaggregative Escherichia coli strains and antibiotic resistance of the isolates in raw milk and unpasteurized cheese. Out of 200 samples of raw milk and 50 samples of unpasteurized cheeses, 96 and 24 strains of E. coli were isolated, respectively. Polymerase chain reaction (PCR was used to detect the genes encoding heat-stable enterotoxin a (STa, heat-stable enterotoxin b (STb, heat labile toxin (LT and enteroaggregative heat-stable toxin1 (EAST1. Twelve out of 120 (10.00% isolates harbored the gene for EAST1, 2(1.66% isolates were detected as producing STb and LT toxins and 12 (10.00% strains contained STb and EAST1 genes. None of the strains contain the STa gene. All of the strains were tested for antibiotic resistance by disk diffusion method. Disks included: ciprofloxacin (CFN, trimetoprim-sulfamethoxazole (TSX, oxytetracycline (OTC, gentamicin (GMN, cephalexin (CPN, nalidixic acid (NDA and nitrofurantoin (NFN, ampicillin (AMP, neomycin (NEO and streptomycin (STM. Among 120 isolated strains of E. coli, the resistance to each antibiotics were as follows: OTC100%, CPN 86.00%, NDA 56.00%, NFN 42.00%, GMN 30.00%, TSX 28.00%, CFN 20%, AM 23.40% and STM 4.25%. None of the isolates were resistant to NEO. The present data indicate that different resistant E. coli pathogens may be found in raw milk and unpasteurized cheese. It poses an infection risk for human and transferring the resistant factors to microflora of the consumers gut.

  7. Genotypic and Phenotypic Characterization of Enterotoxigenic Escherichia coli Strains Isolated from Peruvian Children ▿

    Science.gov (United States)

    Rivera, F. P.; Ochoa, T. J.; Maves, R. C.; Bernal, M.; Medina, A. M.; Meza, R.; Barletta, F.; Mercado, E.; Ecker, L.; Gil, A. I.; Hall, E. R.; Huicho, L.; Lanata, C. F.

    2010-01-01

    Enterotoxigenic Escherichia coli (ETEC) is a major cause of childhood diarrhea. The present study sought to determine the prevalence and distribution of toxin types, colonization factors (CFs), and antimicrobial susceptibility of ETEC strains isolated from Peruvian children. We analyzed ETEC strains isolated from Peruvian children between 2 and 24 months of age in a passive surveillance study. Five E. coli colonies per patient were studied by multiplex real-time PCR to identify ETEC virulence factors. ETEC-associated toxins were confirmed using a GM1-based enzyme-linked immunosorbent assay. Confirmed strains were tested for CFs by dot blot assay using 21 monoclonal antibodies. We analyzed 1,129 samples from children with diarrhea and 744 control children and found ETEC in 5.3% and 4.3%, respectively. ETEC was more frequently isolated from children >12 months of age than from children <12 months of age (P < 0.001). Fifty-two percent of ETEC isolates from children with diarrhea and 72% of isolates from controls were heat-labile enterotoxin (LT) positive and heat-stable enterotoxin (ST) negative; 25% and 19%, respectively, were LT negative and ST positive; and 23% and 9%, respectively, were LT positive and ST positive. CFs were identified in 64% of diarrheal samples and 37% of control samples (P < 0.05). The most common CFs were CS6 (14% and 7%, respectively), CS12 (12% and 4%, respectively), and CS1 (9% and 4%, respectively). ST-producing ETEC strains caused more severe diarrhea than non-ST-producing ETEC strains. The strains were most frequently resistant to ampicillin (71%) and co-trimoxazole (61%). ETEC was thus found to be more prevalent in older infants. LT was the most common toxin type; 64% of strains had an identified CF. These data are relevant in estimating the burden of disease due to ETEC and the potential coverage of children in Peru by investigational vaccines. PMID:20631096

  8. Repair of radiation-induced heat-labile sites is independent of DNA-PKcs, XRCC1 or PARP

    Energy Technology Data Exchange (ETDEWEB)

    Stenerl& #246; w, Bo; Karlsson, Karin H.; Radulescu, Irina; Rydberg, Bjorn; Stenerlow, Bo

    2008-04-29

    Ionizing radiation induces a variety of different DNA lesions: in addition to the most critical DNA damage, the DSB, numerous base alterations, SSBs and other modifications of the DNA double-helix are formed. When several non-DSB lesions are clustered within a short distance along DNA, or close to a DSB, they may interfere with the repair of DSBs and affect the measurement of DSB induction and repair. We have previously shown that a substantial fraction of DSBs measured by pulsed-field gel electrophoresis (PFGE) are in fact due to heat-labile sites (HLS) within clustered lesions, thus reflecting an artifact of preparation of genomic DNA at elevated temperature. To further characterize the influence of HLS on DSB induction and repair, four human cell lines (GM5758, GM7166, M059K, U-1810) with apparently normal DSB rejoining were tested for bi-phasic rejoining after gamma irradiation. When heat-released DSBs were excluded from the measurements the fraction of fast rejoining decreased to less than 50% of the total. However, neither the half-times of the fast (t{sub 1/2} = 7-8 min) or slow (t{sub 1/2} = 2.5 h) DSB rejoining were changed significantly. At t=0 the heat-released DSBs accounted for almost 40% of the DSBs, corresponding to 10 extra DSB/cell/Gy in the initial DSB yield. These heat-released DSBs were repaired within 60-90 min in all tested cells, including M059K cells treated with wortmannin or DNA-PKcs defect M059J cells. Furthermore, cells lacking XRCC1 or Poly(ADP-ribose) polymerase-1 (PARP-1) rejoined both total DSBs and heat-released DSBs similar to normal cells. In summary, the presence of heat-labile sites have a substantial impact on DSB induction yields and DSB rejoining rates measured by pulsed-field gel electrophoresis, and HLS repair is independent of DNA-PKcs, XRCC1 and PARP.

  9. Genotypic and Phenotypic Characterization of Enterotoxigenic Escherichia coli Strains Isolated from Peruvian Children

    Science.gov (United States)

    2010-09-01

    adhesion, ETEC elabo- rates one or both of two enterotoxins: heat-labile toxin (LT), a protein multimer which shares many features with cholera toxin...pathogens (Shigella, Salmonella. Vibrio , Campylo/Jacter, Gi- ardia Iamblia, Cryptosporidium, and rotavirus) by conventional methods. Five lactose...studies performed in developing coun- tries: 38% in children ɚ years of age in Nicaragua (19), 33% in children ə year of age in Mexico (6), and 18% in

  10. Clonal relatedness of enterotoxigenic Escherichia coli (ETEC) strains expressing LT and CS17 isolated from children with diarrhoea in La Paz, Bolivia.

    Science.gov (United States)

    Rodas, Claudia; Klena, John D; Nicklasson, Matilda; Iniguez, Volga; Sjöling, Asa

    2011-01-01

    Enterotoxigenic Escherichia coli (ETEC) is a major cause of traveller's and infantile diarrhoea in the developing world. ETEC produces two toxins, a heat-stable toxin (known as ST) and a heat-labile toxin (LT) and colonization factors that help the bacteria to attach to epithelial cells. In this study, we characterized a subset of ETEC clinical isolates recovered from Bolivian children under 5 years of age using a combination of multilocus sequence typing (MLST) analysis, virulence typing, serotyping and antimicrobial resistance test patterns in order to determine the genetic background of ETEC strains circulating in Bolivia. We found that strains expressing the heat-labile (LT) enterotoxin and colonization factor CS17 were common and belonged to several MLST sequence types but mainly to sequence type-423 and sequence type-443 (Achtman scheme). To further study the LT/CS17 strains we analysed the nucleotide sequence of the CS17 operon and compared the structure to LT/CS17 ETEC isolates from Bangladesh. Sequence analysis confirmed that all sequence type-423 strains from Bolivia had a single nucleotide polymorphism; SNP(bol) in the CS17 operon that was also found in some other MLST sequence types from Bolivia but not in strains recovered from Bangladeshi children. The dominant ETEC clone in Bolivia (sequence type-423/SNP(bol)) was found to persist over multiple years and was associated with severe diarrhoea but these strains were variable with respect to antimicrobial resistance patterns. The results showed that although the LT/CS17 phenotype is common among ETEC strains in Bolivia, multiple clones, as determined by unique MLST sequence types, populate this phenotype. Our data also appear to suggest that acquisition and loss of antimicrobial resistance in LT-expressing CS17 ETEC clones is more dynamic than acquisition or loss of virulence factors.

  11. Clonal Relatedness of Enterotoxigenic Escherichia coli (ETEC) Strains Expressing LT and CS17 Isolated from Children with Diarrhoea in La Paz, Bolivia

    Science.gov (United States)

    Rodas, Claudia; Klena, John D.; Nicklasson, Matilda; Iniguez, Volga; Sjöling, Åsa

    2011-01-01

    Background Enterotoxigenic Escherichia coli (ETEC) is a major cause of traveller's and infantile diarrhoea in the developing world. ETEC produces two toxins, a heat-stable toxin (known as ST) and a heat-labile toxin (LT) and colonization factors that help the bacteria to attach to epithelial cells. Methodology/Principal Findings In this study, we characterized a subset of ETEC clinical isolates recovered from Bolivian children under 5 years of age using a combination of multilocus sequence typing (MLST) analysis, virulence typing, serotyping and antimicrobial resistance test patterns in order to determine the genetic background of ETEC strains circulating in Bolivia. We found that strains expressing the heat-labile (LT) enterotoxin and colonization factor CS17 were common and belonged to several MLST sequence types but mainly to sequence type-423 and sequence type-443 (Achtman scheme). To further study the LT/CS17 strains we analysed the nucleotide sequence of the CS17 operon and compared the structure to LT/CS17 ETEC isolates from Bangladesh. Sequence analysis confirmed that all sequence type-423 strains from Bolivia had a single nucleotide polymorphism; SNPbol in the CS17 operon that was also found in some other MLST sequence types from Bolivia but not in strains recovered from Bangladeshi children. The dominant ETEC clone in Bolivia (sequence type-423/SNPbol) was found to persist over multiple years and was associated with severe diarrhoea but these strains were variable with respect to antimicrobial resistance patterns. Conclusion/Significance The results showed that although the LT/CS17 phenotype is common among ETEC strains in Bolivia, multiple clones, as determined by unique MLST sequence types, populate this phenotype. Our data also appear to suggest that acquisition and loss of antimicrobial resistance in LT-expressing CS17 ETEC clones is more dynamic than acquisition or loss of virulence factors. PMID:22140423

  12. Enhancement of Intranasal Vaccination in Mice with Deglycosylated Chain A Ricin by LTR72, a Novel Mucosal Adjuvant

    National Research Council Canada - National Science Library

    Kende, Meir; Del Giudice, Giuseppe; Rivera, Noelia; Hewetson, John

    2006-01-01

    .... However, in the presence of 4, 2, or 1 microg of the mucosal adjuvant LTR72, a mutant of the heat-labile enterotoxin of Escherichia coli, the low antibody response and protection were substantially enhanced...

  13. Enhancement of Intranasal Vaccination in Mice with Deglycosylated Chain A Ricin by LTR72, a Novel Mucosal Adjuvant

    National Research Council Canada - National Science Library

    Kende, Meir; Del Giudice, Giuseppe; Rivera, Noelia; Hewetson, John

    2006-01-01

    .... However, in the presence of 4, 2, or 1 micro-gram of the mucosal adjuvant LTR72, a mutant of the heat-labile enterotoxin of Escherichia coli, the low antibody response and protection were substantially enhanced...

  14. Immunogenicity of nuclear-encoded LTB:ST fusion protein from Escherichia coli expressed in tobacco plants.

    Science.gov (United States)

    Rosales-Mendoza, Sergio; Soria-Guerra, Ruth E; Moreno-Fierros, Leticia; Govea-Alonso, Dania O; Herrera-Díaz, Areli; Korban, Schuyler S; Alpuche-Solís, Ángel G

    2011-06-01

    Enterotoxigenic Escherichia coli (ETEC) is one of the main causative agents of diarrhea in infants and for travelers. Inclusion of a heat-stable (ST) toxin into vaccine formulations is mandatory as most ETEC strains can produce both heat-labile (LT) and ST enterotoxins. In this study, a genetic fusion gene encoding for an LTB:ST protein has been constructed and transferred into tobacco via Agrobacterium tumefaciens-mediated transformation. Transgenic tobacco plants carrying the LTB:ST gene are then subjected to GM1-ELISA revealing that the LTB:ST has assembled into pentamers and displays antigenic determinants from both LTB and ST. Protein accumulation of up to 0.05% total soluble protein is detected. Subsequently, mucosal and systemic humoral responses are elicited in mice orally dosed with transgenic tobacco leaves. This has suggested that the plant-derived LTB:ST is immunogenic via the oral route. These findings are critical for the development of a plant-based vaccine capable of eliciting broader protection against ETEC and targeting both LTB and ST. Features of this platform in comparison to transplastomic approaches are discussed.

  15. X-ray crystal structure of the passenger domain of plasmid encoded toxin(Pet), an autotransporter enterotoxin from enteroaggregative Escherichia coli (EAEC)

    Energy Technology Data Exchange (ETDEWEB)

    Domingo Meza-Aguilar, J. [Departamento de Salud Pública Facultad de Medicina UNAM, Ciudad Universitaria Coyoacán 04510, D.F. (Mexico); Laboratorio de Patogenicidad Bacteriana, Unidad de Hemato Oncología e Investigación, Hospital Infantil de México Federico Gómez 06720, D.F. (Mexico); Fromme, Petra [Department of Chemistry and Biochemistry, Arizona State University, Physical Sciences BLDG D-102, Tempe, AZ 85287 (United States); Torres-Larios, Alfredo [Instituto de Fisiología Celular UNAM, Ciudad Universitaria Coyoacán 04510, D.F. (Mexico); Mendoza-Hernández, Guillermo [Instituto de Química UNAM, Ciudad Universitaria Coyoacán 04510, D.F (Mexico); Hernandez-Chiñas, Ulises [Departamento de Salud Pública Facultad de Medicina UNAM, Ciudad Universitaria Coyoacán 04510, D.F. (Mexico); Laboratorio de Patogenicidad Bacteriana, Unidad de Hemato Oncología e Investigación, Hospital Infantil de México Federico Gómez 06720, D.F. (Mexico); Arreguin-Espinosa de los Monteros, Roberto A. [Instituto de Química UNAM, Ciudad Universitaria Coyoacán 04510, D.F (Mexico); and others

    2014-03-07

    Highlights: • X-ray crystal structure of the passenger domain of Plasmid encoded toxin at 2.3 Å. • Structural differences between Pet passenger domain and EspP protein are described. • High flexibility of the C-terminal beta helix is structurally assigned. - Abstract: Autotransporters (ATs) represent a superfamily of proteins produced by a variety of pathogenic bacteria, which include the pathogenic groups of Escherichia coli (E. coli) associated with gastrointestinal and urinary tract infections. We present the first X-ray structure of the passenger domain from the Plasmid-encoded toxin (Pet) a 100 kDa protein at 2.3 Å resolution which is a cause of acute diarrhea in both developing and industrialized countries. Pet is a cytoskeleton-altering toxin that induces loss of actin stress fibers. While Pet (pdb code: 4OM9) shows only a sequence identity of 50% compared to the closest related protein sequence, extracellular serine protease plasmid (EspP) the structural features of both proteins are conserved. A closer structural look reveals that Pet contains a β-pleaded sheet at the sequence region of residues 181–190, the corresponding structural domain in EspP consists of a coiled loop. Secondary, the Pet passenger domain features a more pronounced beta sheet between residues 135 and 143 compared to the structure of EspP.

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

    Directory of Open Access Journals (Sweden)

    Outi Nyholm

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

  17. Treatment of PCR products with exonuclease I and heat-labile alkaline phosphatase improves the visibility of combined bisulfite restriction analysis

    International Nuclear Information System (INIS)

    Watanabe, Kousuke; Emoto, Noriko; Sunohara, Mitsuhiro; Kawakami, Masanori; Kage, Hidenori; Nagase, Takahide; Ohishi, Nobuya; Takai, Daiya

    2010-01-01

    Research highlights: → Incubating PCR products at a high temperature causes smears in gel electrophoresis. → Smears interfere with the interpretation of methylation analysis using COBRA. → Treatment with exonuclease I and heat-labile alkaline phosphatase eliminates smears. → The elimination of smears improves the visibility of COBRA. -- Abstract: DNA methylation plays a vital role in the regulation of gene expression. Abnormal promoter hypermethylation is an important mechanism of inactivating tumor suppressor genes in human cancers. Combined bisulfite restriction analysis (COBRA) is a widely used method for identifying the DNA methylation of specific CpG sites. Here, we report that exonuclease I and heat-labile alkaline phosphatase can be used for PCR purification for COBRA, improving the visibility of gel electrophoresis after restriction digestion. This improvement is observed when restriction digestion is performed at a high temperature, such as 60 o C or 65 o C, with BstUI and TaqI, respectively. This simple method can be applied instead of DNA purification using spin columns or phenol/chloroform extraction. It can also be applied to other situations when PCR products are digested by thermophile-derived restriction enzymes, such as PCR restriction fragment length polymorphism (RFLP) analysis.

  18. In-silico design, expression, and purification of novel chimeric Escherichia coli O157:H7 OmpA fused to LTB protein in Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Aytak Novinrooz

    Full Text Available E. coli O157:H7, one of the major EHEC serotypes, is capable of developing bloody diarrhea, hemorrhagic colitis (HC, and fatal hemolytic uremic syndrome (HUS and is accompanied by high annual economic loss worldwide. Due to the increased risk of HC and HUS development following antibiotic therapy, the prevention of infections caused by this pathogen is considered to be one of the most effective ways of avoiding the consequences of this infection. The main aim of the present study was to design, express, and purify a novel chimeric protein to develope human vaccine candidate against E. coli O157:H7 containing loop 2-4 of E. coli O157:H7, outer membrane protein A (OmpA, and B subunit of E. coli heat labile enterotoxin (LTB which are connected by a flexible peptide linker. Several online databases and bioinformatics software were utilized to choose the peptide linker among 537 analyzed linkers, design the chimeric protein, and optimize the codon of the relative gene encoding this protein. Subsequently, the recombinant gene encoding OmpA-LTB was synthesized and cloned into pET-24a (+ expression vector and transferred to E. coli BL21(DE3 cells. The expression of OmpA-LTB chimeric protein was then carried out by induction of cultured E. coli Bl21 (DE3 cells with 1mM isopropyl-β-D-thiogalactopyranoside (IPTG. The purification of OmpA-LTB was then performed by nickel affinity chromatography. Expression and purification were analyzed by sodium dodecyl sulphate poly acrylamide gel electrophoresis. Moreover, the identity of the expressed protein was analyzed by western blotting. SDS-PAGE and western immunoblotting confirmed the successful expression of a 27 KDa recombinant protein after 24 hours at 37°C post-IPTG induction. OmpA-LTB was then successfully purified, using nickel affinity chromatography under denaturing conditions. The yield of purification was 12 mg per liter of culture media. Ultimately, we constructed the successful design and efficient

  19. Production of Escherichia coli heat labile toxin (LT) B subunit in soybean seed and analysis of its immunogenicity as an oral vaccine

    Czech Academy of Sciences Publication Activity Database

    Moravec, Tomáš; Schmidt, M.A.; Herman, E.M.; Woodford-Thomas, T.

    2007-01-01

    Roč. 25, - (2007), s. 1647-1657 ISSN 0264-410X Grant - others:Marie Curie Fellowship(XE) MOIF CT 2005-008692 Institutional research plan: CEZ:AV0Z50380511 Keywords : Microbial toxin * Plant-based vaccines * Transgenic soybean seed Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.377, year: 2007

  20. Cloning the enterotoxin gene from Clostridium perfringens type A

    OpenAIRE

    Iwanejko, Lesley Ann.

    1991-01-01

    A C. perfringens type A genomic library was constructed in E. coli by banking overlapping 6-10 kbp Hind III fragments of chromosomal DNA from the enterotoxin (CPE) positive strain NCTC 8239 into the pUC derived vector pHG165. The library was screened by colony hybridization with a degenerate 26 bp oligonucleotide probe, derived from the amino acid sequence CPE9_17A. complex mixture of plasmid DNA was isolated from the only hybridization positive clone. A second round of screening picked out a...

  1. Cloning and Expression of Nano Body Gene against Enterotoxin B of Staphylococcus Aureus

    Directory of Open Access Journals (Sweden)

    Zahra Tavassoli

    2017-02-01

    Full Text Available Background & Objectives: Staphylococcus aureus bacteria causes many different diseases by secretion of various enterotoxins. Therefore, it is necessary to develop ways that facilitate the detection of enterotoxins. Nowadays, immunochemical methods which are based on monoclonal antibody technology are used. The heavy chain antibodies that are called VHH or Nano body were found in blood serum of the Camelidae family. The unique properties of this antibody such as their binding to small molecules like toxins make them attractive candidates for the development of immunodiagnostic tests. The present study was done to achieve a VHH molecules against Staphylococcus enterotoxin B. Materials & Methods: Freighting phage library for isolate private Nano bodies against enterotoxin B was done in previous works. Next, pCANTAB 5E vector that consists VHH, extracted from E.coli bacteria strain xl1blue, and after doing PCR process with relative primers, sub cloning in pET21a(+ as an expression vector with cut sites NdeI and XhoI was done. Transformation in E.coli bacteria strain BL21(DE3 was done. Then, the cells effected with IPTG and producing time, and other terms were optimized. Finally, the expression of the protein with SDS-PAGE and western blot techniques was evaluated. Result: For proving cloning of nano body gene in pET21a (+ vector, nucleotide sequence of gene was analyzed, and transforming to E.coli bacteria strain BL21(DE3 was successful. After inspiration, active protein in cell was seen by SDS-PAGE technique and proved by western blot. Conclusion: cloning, sub cloning, and nonabody expression were surveyed in this research. Production of this protein can help to develop new therapeutic methods and produce vaccine against enterotoxin B of Staphylococcus aureus

  2. The oral, live attenuated enterotoxigenic Escherichia coli vaccine ACE527 reduces the incidence and severity of diarrhea in a human challenge model of diarrheal disease.

    Science.gov (United States)

    Darsley, Michael J; Chakraborty, Subhra; DeNearing, Barbara; Sack, David A; Feller, Andrea; Buchwaldt, Charlotte; Bourgeois, A Louis; Walker, Richard; Harro, Clayton D

    2012-12-01

    An oral, live attenuated, three-strain recombinant bacterial vaccine, ACE527, was demonstrated to generate strong immune responses to colonization factor and toxin antigens of enterotoxigenic Escherichia coli (ETEC) in human volunteers. The vaccine was safe and well tolerated at doses of up to 10(11) CFU, administered in each of two doses given 21 days apart. These observations have now been extended in a phase 2b study with a total of 70 subjects. Fifty-six of these subjects were challenged 28 days after the second dose of vaccine with the highly virulent ETEC strain H10407 to obtain preliminary indicators of efficacy against disease and to support further development of the vaccine for both travelers and infants in countries where ETEC is endemic. The vaccine had a significant impact on intestinal colonization by the challenge strain, as measured by quantitative fecal culture 2 days after challenge, demonstrating the induction of a functional immune response to the CFA/I antigen. The incidence and severity of diarrhea were also reduced in vaccinees as measured by a number of secondary and ad hoc endpoints, although the 27% reduction seen in the primary endpoint, moderate to severe diarrhea, was not statistically significant. Together, these observations support the hypothesis that the ACE527 vaccine has a dual mode of action, targeting both colonization factors and the heat-labile enterotoxin (LT), and suggest that it should be further developed for more advanced trials to evaluate its impact on the burden of ETEC disease in field settings.

  3. Double antibody solid-phase radioimmunoassay for staphylococcal enterotoxin A

    International Nuclear Information System (INIS)

    Lindroth, S.; Niskanen, A.

    1977-01-01

    A double antibody solid-phase (DASP) radioimmunoassay for staphylococcal enterotoxin A is described. In the assay the antigen-antibody complex is precipitated by anti-rabbit serum which is adsorbed onto a solid carrier (cellulose). The method is sensitive to 200 pg of enterotoxin. It was possible to detect a little as 2-5 ng of enterotoxin A/ml food extract from minced meat and sausage. Enterotoxins B and C were not found to inhibit the uptake of labled enterotoxin A at a level which might distort the results of the enterotoxin A assay. The DASP technique is sensitive, rapid, and easy to perform and thus compares favorably with other radioimmunoassays for enterotoxin. (orig.) [de

  4. Staphylococcal aureus Enterotoxin C and Enterotoxin-Like L Associated with Post-partum Mastitis

    DEFF Research Database (Denmark)

    Franck, Kristina T; Gumpert, Heidi; Olesen, Bente

    2017-01-01

    between isolates from the two outbreaks revealed a S. aureus pathogenicity island containing enterotoxin C and enterotoxin-like L only in isolates from outbreak 2. Enterotoxin C and enterotoxin-like L carrying S. aureus are associated with bovine mastitis and our findings indicate that these may also...... PVL and ACME negative. In outbreak 1, the isolates harbored SCCmec IVa and in outbreak 2 SCCmec V. The clinical presentation differed between the two outbreaks, as none of five MRSA positive mothers in outbreak 1 had mastitis vs. five of six MRSA positive mothers in outbreak 2 (p ....02). To investigate if whole-genome sequencing could identify virulence genes associated with mastitis, t015:ST45 isolates from Denmark (N = 101) were whole-genome sequenced. Sequence analysis confirmed two separate outbreaks with no sign of sustained spread into the community. Analysis of the accessory genome...

  5. Nanodisc-based Co-immunoprecipitation for Mass Spectrometric Identification of Membrane-interacting Proteins

    DEFF Research Database (Denmark)

    Borch-Jensen, Jonas; Roepstorff, Peter; Møller-Jensen, Jakob

    2011-01-01

    enterotoxigenic Escherischia coli, GM1-nanodiscs were employed for co-immunoprecipitation. The B subunit of heat labile enterotoxin was identified as a specific interaction partner by mass spectrometry, thus demonstrating that nanodisc technology is useful for highly specific detection and identification...

  6. Treponema pallidum 3-Phosphoglycerate Mutase Is a Heat-Labile Enzyme That May Limit the Maximum Growth Temperature for the Spirochete

    Science.gov (United States)

    Benoit, Stéphane; Posey, James E.; Chenoweth, Matthew R.; Gherardini, Frank C.

    2001-01-01

    In the causative agent of syphilis, Treponema pallidum, the gene encoding 3-phosphoglycerate mutase, gpm, is part of a six-gene operon (tro operon) that is regulated by the Mn-dependent repressor TroR. Since substrate-level phosphorylation via the Embden-Meyerhof pathway is the principal way to generate ATP in T. pallidum and Gpm is a key enzyme in this pathway, Mn could exert a regulatory effect on central metabolism in this bacterium. To study this, T. pallidum gpm was cloned, Gpm was purified from Escherichia coli, and antiserum against the recombinant protein was raised. Immunoblots indicated that Gpm was expressed in freshly extracted infective T. pallidum. Enzyme assays indicated that Gpm did not require Mn2+ while 2,3-diphosphoglycerate (DPG) was required for maximum activity. Consistent with these observations, Mn did not copurify with Gpm. The purified Gpm was stable for more than 4 h at 25°C, retained only 50% activity after incubation for 20 min at 34°C or 10 min at 37°C, and was completely inactive after 10 min at 42°C. The temperature effect was attenuated when 1 mM DPG was added to the assay mixture. The recombinant Gpm from pSLB2 complemented E. coli strain PL225 (gpm) and restored growth on minimal glucose medium in a temperature-dependent manner. Increasing the temperature of cultures of E. coli PL225 harboring pSLB2 from 34 to 42°C resulted in a 7- to 11-h period in which no growth occurred (compared to wild-type E. coli). These data suggest that biochemical properties of Gpm could be one contributing factor to the heat sensitivity of T. pallidum. PMID:11466272

  7. Staphylococcus aureus enterotoxins A- and B

    DEFF Research Database (Denmark)

    Danielsen, E Michael; Hansen, Gert H; Karlsdóttir, Edda

    2013-01-01

    Enterotoxins of Staphylococcus aureus are among the most common causes of food poisoning. Acting as superantigens they intoxicate the organism by causing a massive uncontrolled T cell activation that ultimately may lead to toxic shock and death. In contrast to our detailed knowledge regarding...

  8. Possible Application of Biotechnology to the Development of Biological Agents by Potential Enemies

    Science.gov (United States)

    1987-06-01

    7 beta chains Shigella dysenteriae type 1 plus other Inhibits 60S ribosome in eukaryotes -22- E. coli enterotoxin (heat labile) 2 subunits...toxin and those from E. colt because they do not act directly on intestinal cells. The same clinical response is obtained in monkeys following...there arc few good models in which to stud> the toxicity of the enterotoxins. Monkeys show many of the symptoms of toxic shock syndrome, however

  9. Basis of Virulence in Enterotoxin-Mediated Staphylococcal Food Poisoning

    Directory of Open Access Journals (Sweden)

    Emilie L. Fisher

    2018-03-01

    Full Text Available The Staphylococcus aureus enterotoxins are a superfamily of secreted virulence factors that share structural and functional similarities and possess potent superantigenic activity causing disruptions in adaptive immunity. The enterotoxins can be separated into two groups; the classical (SEA-SEE and the newer (SEG-SElY and counting enterotoxin groups. Many members from both these groups contribute to the pathogenesis of several serious human diseases, including toxic shock syndrome, pneumonia, and sepsis-related infections. Additionally, many members demonstrate emetic activity and are frequently responsible for food poisoning outbreaks. Due to their robust tolerance to denaturing, the enterotoxins retain activity in food contaminated previously with S. aureus. The genes encoding the enterotoxins are found mostly on a variety of different mobile genetic elements. Therefore, the presence of enterotoxins can vary widely among different S. aureus isolates. Additionally, the enterotoxins are regulated by multiple, and often overlapping, regulatory pathways, which are influenced by environmental factors. In this review, we also will focus on the newer enterotoxins (SEG-SElY, which matter for the role of S. aureus as an enteropathogen, and summarize our current knowledge on their prevalence in recent food poisoning outbreaks. Finally, we will review the current literature regarding the key elements that govern the complex regulation of enterotoxins, the molecular mechanisms underlying their enterotoxigenic, superantigenic, and immunomodulatory functions, and discuss how these activities may collectively contribute to the overall manifestation of staphylococcal food poisoning.

  10. Suppression of colorectal tumorigenesis by recombinant Bacteroides fragilis enterotoxin-2 in vivo

    OpenAIRE

    Lv, You; Ye, Tao; Wang, Hui-Peng; Zhao, Jia-Ying; Chen, Wen-Jie; Wang, Xin; Shen, Chen-Xia; Wu, Yi-Bin; Cai, Yuan-Kun

    2017-01-01

    AIM To evaluate the impact of recombinant Bacteroides fragilis enterotoxin-2 (BFT-2, or Fragilysin) on colorectal tumorigenesis in mice induced by azoxymethane/dextran sulfate sodium (AOM/DSS). METHODS Recombinant proBFT-2 was expressed in Escherichia coli strain Rosetta (DE3) and BFT-2 was obtained and tested for its biological activity via colorectal adenocarcinoma cell strains SW-480. Seventy C57BL/6J mice were randomly divided into a blank (BC; n = 10), model (AD; n = 20), model + low-dos...

  11. Lactobacillus plantarum BSGP201683 Isolated from Giant Panda Feces Attenuated Inflammation and Improved Gut Microflora in Mice Challenged with Enterotoxigenic Escherichia coli

    Directory of Open Access Journals (Sweden)

    Qian Liu

    2017-09-01

    Full Text Available In this work, we searched for an effective probiotic that can help control intestinal infection, particularly enterotoxigenic Escherichia coli K88 (ETEC invasion, in giant panda (Ailuropoda melanoleuca. As a potential probiotic strain, Lactobacillus plantarum BSGP201683 (L. plantarum G83 was isolated from the feces of giant panda and proven beneficial in vitro. This study was aimed to evaluate the protective effect of L. plantarum G83 in mice challenged with ETEC. The mice were orally administered with 0.2 mL of PBS containing L. plantarum G83 at 0 colony-forming units (cfu mL−1 (control; negative control, ETEC group, 5.0 × 108 cfu mL−1 (LDLP, 5.0 × 109 cfu mL−1 (MDLP, and 5.0 × 1010 cfu mL−1 (HDLP for 14 consecutive days. At day 15, the mice (LDLP, MDLP, HDLP, and ETEC groups were challenged with ETEC and assessed at 0, 24, and 144 h. Animal health status; chemical and biological intestinal barriers; and body weight were measured. Results showed that L. plantarum G83 supplementation protected the mouse gut mainly by attenuating inflammation and improving the gut microflora. Most indices significantly changed at 24 h after challenge compared to those at 0 and 144 h. All treatment groups showed inhibited plasma diamine oxidase activity and D-lactate concentration. Tight-junction protein expression was down-regulated, and interleukin (IL-1β, IL-6, IL-8, TLR4, and MyD88 levels were up-regulated in the jejunum in the LDLP and MDLP groups. The number of the Enterobacteriaceae family and the heat-labile enterotoxin (LT gene decreased (P < 0.05 in the colons in the LDLP and MDLP groups. All data indicated that L. plantarum G83 could attenuate acute intestinal inflammation caused by ETEC infection, and the low and intermediate doses were superior to the high dose. These findings suggested that L. plantarum G83 may serve as a protective probiotic for intestinal disease and merits further investigation.

  12. Lactobacillus plantarum BSGP201683 Isolated from Giant Panda Feces Attenuated Inflammation and Improved Gut Microflora in Mice Challenged with Enterotoxigenic Escherichia coli.

    Science.gov (United States)

    Liu, Qian; Ni, Xueqin; Wang, Qiang; Peng, Zhirong; Niu, Lili; Wang, Hengsong; Zhou, Yi; Sun, Hao; Pan, Kangcheng; Jing, Bo; Zeng, Dong

    2017-01-01

    In this work, we searched for an effective probiotic that can help control intestinal infection, particularly enterotoxigenic Escherichia coli K88 (ETEC) invasion, in giant panda ( Ailuropoda melanoleuca ). As a potential probiotic strain, Lactobacillus plantarum BSGP201683 ( L. plantarum G83) was isolated from the feces of giant panda and proven beneficial in vitro . This study was aimed to evaluate the protective effect of L. plantarum G83 in mice challenged with ETEC. The mice were orally administered with 0.2 mL of PBS containing L. plantarum G83 at 0 colony-forming units (cfu) mL -1 (control; negative control, ETEC group), 5.0 × 10 8 cfu mL -1 (LDLP), 5.0 × 10 9 cfu mL -1 (MDLP), and 5.0 × 10 10 cfu mL -1 (HDLP) for 14 consecutive days. At day 15, the mice (LDLP, MDLP, HDLP, and ETEC groups) were challenged with ETEC and assessed at 0, 24, and 144 h. Animal health status; chemical and biological intestinal barriers; and body weight were measured. Results showed that L. plantarum G83 supplementation protected the mouse gut mainly by attenuating inflammation and improving the gut microflora. Most indices significantly changed at 24 h after challenge compared to those at 0 and 144 h. All treatment groups showed inhibited plasma diamine oxidase activity and D -lactate concentration. Tight-junction protein expression was down-regulated, and interleukin (IL)-1β, IL-6, IL-8, TLR4, and MyD88 levels were up-regulated in the jejunum in the LDLP and MDLP groups. The number of the Enterobacteriaceae family and the heat-labile enterotoxin (LT) gene decreased ( P < 0.05) in the colons in the LDLP and MDLP groups. All data indicated that L. plantarum G83 could attenuate acute intestinal inflammation caused by ETEC infection, and the low and intermediate doses were superior to the high dose. These findings suggested that L. plantarum G83 may serve as a protective probiotic for intestinal disease and merits further investigation.

  13. A modified multiscale peak alignment method combined with trilinear decomposition to study the volatile/heat-labile components in Ligusticum chuanxiong Hort - Cyperus rotundus rhizomes by HS-SPME-GC/MS.

    Science.gov (United States)

    He, Min; Yan, Pan; Yang, Zhi-Yu; Zhang, Zhi-Min; Yang, Tian-Biao; Hong, Liang

    2018-03-15

    Head Space/Solid Phase Micro-Extraction (HS-SPME) coupled with Gas Chromatography/Mass Spectrometer (GC/MS) was used to determine the volatile/heat-labile components in Ligusticum chuanxiong Hort - Cyperus rotundus rhizomes. Facing co-eluting peaks in k samples, a trilinear structure was reconstructed to obtain the second-order advantage. The retention time (RT) shift with multi-channel detection signals for different samples has been vital in maintaining the trilinear structure, thus a modified multiscale peak alignment (mMSPA) method was proposed in this paper. The peak position and peak width of representative ion profile were firstly detected by mMSPA using Continuous Wavelet Transform with Haar wavelet as the mother wavelet (Haar CWT). Then, the raw shift was confirmed by Fast Fourier Transform (FFT) cross correlation calculation. To obtain the optimal shift, Haar CWT was again used to detect the subtle deviations and be amalgamated in calculation. Here, to ensure there is no peaks shape alternation, the alignment was performed in local domains of data matrices, and all data points in the peak zone were moved via linear interpolation in non-peak parts. Finally, chemical components of interest in Ligusticum chuanxiong Hort - Cyperus rotundus rhizomes were analyzed by HS-SPME-GCMS and mMSPA-alternating trilinear decomposition (ATLD) resolution. As a result, the concentration variation between herbs and their pharmaceutical products can provide a scientific basic for the quality standard establishment of traditional Chinese medicines. Copyright © 2018 Elsevier B.V. All rights reserved.

  14. Production of staphylococcal enterotoxin A in cream-filled cake.

    Science.gov (United States)

    Anunciaçao, L L; Linardi, W R; do Carmo, L S; Bergdoll, M S

    1995-07-01

    Cakes were baked with normal ingredients and filled with cream, inoculated with different size enterotoxigenic-staphylococcal inocula. Samples of the cakes were incubated at room temperature and put in the refrigerator. Samples of cake and filling were taken at different times and analyzed for staphylococcal count and presence of enterotoxin. The smaller the inoculum, the longer the time required for sufficient growth (10(6)) to occur for production of detectable enterotoxin. Enterotoxin added to the cake dough before baking (210 degrees C, 45 min) did not survive the baking. The presence of enterotoxin in the contaminated cream filling indicated this as the cause of staphylococcal food poisoning from cream-filled cakes. Refrigeration of the cakes prevented the growth of the staphylococci.

  15. Comparative genomics and transcriptomics of Escherichia coli isolates carrying virulence factors of both enteropathogenic and enterotoxigenic E. coli.

    Science.gov (United States)

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

    2017-06-14

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

  16. Multiple loci affecting photoreactivation in Escherichia coli

    International Nuclear Information System (INIS)

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

    1979-01-01

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

  17. Production of enterotoxin by Salmonella exposed to X rays

    International Nuclear Information System (INIS)

    Szulc, M.; Pliszka, A.; Peconek, J.

    1982-01-01

    The influence of irradiation on enterotoxin production by Salmonella enteritidis and S. typhimurium was evaluated using skin test elaborated by Tschaepe and others. The strains examined appeared to be equally sensitive to X rays. A dose of 100 Gy decreased the number of bacterial cells at approx. 10 D 10 and 200 Gy at 2-3 D 10 . Irradiation with 100 and 200 Gy of X rays did not influence enterotoxin production by microorganisms which were resistant to the process of irradiation. (author)

  18. Simulation of carbohydrate-protein interactions : Computer-aided design of a second generation GM1 mimic

    NARCIS (Netherlands)

    Bernardi, A; Galgano, M; Belvisi, L; Colombo, G

    The oligosaccharide of ganglioside GM1 [Gal beta1-3GalNAc beta1-4(NeuAc alpha2-3)Gal beta1-4Glc beta1-1Cer] is the cellular target of two bacterial enterotoxins: the cholera toxin (CT) and the heat-labile toxin of E.coli (LT). We recently reported that the pseudosaccharide 2[Gal beta1-3GalNAc

  19. Prevalence of enterotoxigenic Bacillus Cereus and Its enterotoxins ...

    African Journals Online (AJOL)

    Objectives: To determine the prevalence of enterotoxigenic Bacillus cereus (B. cereus) and enterotoxins in milk and milk products. Design: A random sampling of milk products was carried out. Setting: Market milk and milk products were collected from retail shops in Nairobi and analysed for contamination with ...

  20. Prevalence, antibiotic-resistance properties and enterotoxin gene ...

    African Journals Online (AJOL)

    Prevalence, antibiotic-resistance properties and enterotoxin gene profile of Bacillus cereus strains isolated from milk-based baby foods. ... Conclusion: Considerable prevalence of resistant and toxigenic B. cereus and high consumption of milk-based infant foods in Iran, represent an important public health issue which ...

  1. Construction of PVX virus-expression vector to express enterotoxin ...

    African Journals Online (AJOL)

    Potato X potyvirus (PVX)-based vector has been comprehensively applied in transient expression system. In order to produce the heterologous proteins more quickly and stably, the ClaI and NotI enzyme sites were introduced into the Enterotoxin fusion gene LTB-ST by polymerase chain reaction (PCR) and the LTB-ST ...

  2. Studies on the mechanism of action of enterotoxin-induced fluid secretion in the gut

    International Nuclear Information System (INIS)

    Schirgi-Degen, A.

    1992-12-01

    The mechanism of action of Clostridium difficile enterotoxin A (CA), of Escherichia coli enterotoxin (STa) and of cholera toxin (CT), which are known to cause severe diarrhea, were studied in a preparation of ligated jejunal loops of anesthetized rats in vivo. The toxins were administered intraluminally. Pharmacological agents, which were tested for their potency to influence toxin-related effects, were administered subcutaneously. Net fluid transport was determined gravimetrically, prostaglandin (PG) E 2 -output into the lumen, cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) contents in the mucosa were measured by radioimmunoassay, serotonin-(5-HT)-output into the lumen was determined by high performance liquid chromatography. The histopathological effects of CA and CT were examined by light- and scanning electron microscopy. All three toxins caused net fluid secretion (FS). 5-HT 2 -(ketanserin) and 5-HT 3 -receptor antagonists (tropisetron, ondansetron, granisetron) dose-dependently reduced or abolished CT- and STa-induced net FS, CA-induced net FS was not influenced. Indomethacin reduced CA-, CT- and STa-induced net FS. Elevation of PGE 2 -output occurred after exposure to CA and CT and was reduced by indomethacin. CA caused severe histopathological lesions and also CT time-dependently caused morphological changes, which may take part in the secretory response. It is concluded that 5-HT, using both 5-HT 2 - and 5-HT 3 -receptors, mediates CT- and STa, but not CA-induced FS. PGE 2 is involved in FS caused by all three toxins. CAMP and cGMP are presumedly no causative mediators of toxin-induced FS

  3. The three-dimensional crystal structure of cholera toxin

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Rong-Guang; Westbrook, M.L.; Nance, S.; Spangler, B.D. [Argonne National Lab., IL (United States); Scott, D.L. [Yale Univ., New Haven, CT (United States). Dept. of Molecular Biophysics and Biochemistry; Westbrook, E.M. [Northwestern Univ., Evanston, IL (United States)

    1996-02-01

    The clinical manifestations of cholera are largely attributable to the actions of a secreted hexameric AB{sub 5} enterotoxin (choleragen). We have solved the three-dimensional structure of choleragen at 2.5 {Angstrom} resolution and compared the refined coordinates with those of choleragenoid (isolated B pentamer) and the heat-labile enterotoxin from Escherichia coli (LT). The crystalline coordinates provide a detailed view of the stereochemistry implicated in binding to GM1 gangliosides and in carrying out ADP-ribosylation. The A2 chain of choleragen, in contrast to that of LT, is a nearly continuous {alpha}-helix with an interpretable carboxyl tail.

  4. Evaluation of an alternative extraction procedure for enterotoxin determination in dairy products.

    Science.gov (United States)

    Meyrand, A; Atrache, V; Bavai, C; Montet, M P; Vernozy-Rozand, C

    1999-06-01

    A concentration protocol based on trichloroacetic acid precipitation was evaluated and compared with the reference method using dialysis concentration. Different quantities of purified staphylococcal enterotoxins were added to pasteurized Camembert-type cheeses. Detection of enterotoxins in these cheeses was performed using an automated detection system. Raw goat milk Camembert-type cheeses involved in a staphylococcal food poisoning were also tested. Both enterotoxin extraction methods allowed detection of the lowest enterotoxin concentration level used in this study (0.5 ng g-1). Compared with the dialysis concentration method, TCA precipitation of staphylococcal enterotoxins was 'user-friendly' and less time-consuming. These results suggest that TCA precipitation is a rapid (1 h), simple and reliable method of extracting enterotoxin from food which gives excellent recovery from dairy products.

  5. Stimulation of Clostridium perfringens enterotoxin formation by caffeine and theobromine.

    Science.gov (United States)

    Labbe, R G; Nolan, L L

    1981-01-01

    In the presence of 100 micrograms of caffeine per ml or 200 micrograms of theobromine per ml, sporulation of Clostridium perfringens NCTC 8679 rose from less than 1 to 80 or 85%. Enterotoxin concentration increased from undetectable levels to 450 micrograms/mg of cell extract protein. Heat-resistant spore levels increased from less than 1,000 to between 1 X 10(7) and 2 X 10(7)/ml. These effects were partially reversible by the addition of adenosine or thymidine. In the case of NCTC 8238, caffeine and theobromine caused a three- to fourfold increase in the percentages of cells possessing refractile spores and a similar increase in enterotoxin concentration. Heat-resistant spore levels, however, were unaffected. Inosine was ineffective in promoting sporulation in NCTC 8679. PMID:6271685

  6. Monkey Feeding Assay for Testing Emetic Activity of Staphylococcal Enterotoxin.

    Science.gov (United States)

    Seo, Keun Seok

    2016-01-01

    Staphylococcal enterotoxins (SEs) are unique bacterial toxins that cause gastrointestinal toxicity as well as superantigenic activity. Since systemic administration of SEs induces superantigenic activity leading to toxic shock syndrome that may mimic enterotoxic activity of SEs such as vomiting and diarrhea, oral administration of SEs in the monkey feeding assay is considered as a standard method to evaluate emetic activity of SEs. This chapter summarizes and discusses practical considerations of the monkey feeding assay used in studies characterizing classical and newly identified SEs.

  7. The prevalence of methicillin-resistant Staph. aureus strains producing enterotoxin A and B

    Directory of Open Access Journals (Sweden)

    Safiyeh Abbasi

    2016-02-01

    Full Text Available Background: Staphylococcus aureus is a gram positive coccus which is able to cause different kinds of infection in certain condition. The function of this bacteria is to provide the conditions for the invasion of it to the host with the secretion of different sorts of toxins such as Staphylococcus aureus enterotoxin, including important virulence factors that super antigens are all factors digestive inconvenience. Staphylococcus aureus enterotoxin-secreting toxins such conditions provides invasion of host genes. There are different types of SE, but type A enterotoxin (SEA and type B enterotoxin (SEB are the most important types. Therefore, in this study, the prevalence of Staphylococcus aureus toxin-producing enterotoxin genes (SEB, SEA in clinical strains isolated from patients in teaching hospitals of Shahrekord city, Iran, were studied. Methods: This cross-sectional and descriptive study, which was conducted from May 2014 to December 2014. A hundred and ten isolates of Staphylococcus aureus from patients collected over a period of 8 months and were first identified using standard biochemical methods and laboratory. Using standard methods and laboratory tests were identified and compared with the antibiotic oxacillin minimum inhibitory concentration were determined by broth micro dilution, and then they were assessed by polymerase chain reaction (PCR technique. Results: The results indicated that, 110 samples of dairy products infected by Staphylococcus aureus were detected. Two cases (1.8% of these infected samples were carrying both enterotoxin A and enterotoxin B genes. The frequencies of enterotoxin A genes were twenty-six cases (23/6% and The frequencies of enterotoxin B genes were two cases (1/8%, respectively. Conclusion: The detection of enterotoxin A and enterotoxin B genes, shows the most important role they have in bringing about superinfection. The detection of enterotoxin A and B genes, shows the most important role they have in

  8. Growth and enterotoxin production of Bacillus cereus in cow, goat, and sheep milk

    Directory of Open Access Journals (Sweden)

    Lenka Necidová

    2014-01-01

    Full Text Available The aim of this study was to compare Bacillus cereus growth rates and diarrhoeal enterotoxin production in raw and pasteurized goat, sheep, and cow milk in terms of storage conditions. Milk samples were inoculated with B. cereus (CCM 2010, which produces diarrhoeal enterotoxins. Enterotoxin production was tested by ELISA (Enzyme-Linked Immunosorbent Assay, and the count of B. cereus was determined by the plate method. With raw cow milk, B. cereus growth and enterotoxin production can be completely suppressed; in raw goat and sheep milk, enterotoxin was produced at 22 °C. In pasteurized cow, goat, and sheep milk, the B. cereus count increased under all storage conditions, with more rapid growth being observed at 15 °C (sheep milk and 22 °C (cow and goat milk. Enterotoxin presence was detected at 15 °C and 22 °C, and with pasteurized cow milk also at 8 °C. Our model experiments have determined that B. cereus multiplication and subsequent enterotoxin production depend on storage temperature and milk type.

  9. Volunteer Challenge With Enterotoxigenic Escherichia coli That Express Intestinal Colonization Factor Fimbriae CS17 and CS19

    Science.gov (United States)

    2011-07-01

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

  10. Randomised, double-blind, safety and efficacy of a killed oral vaccine for enterotoxigenic E. Coli diarrhoea of travellers to Guatemala and Mexico.

    Science.gov (United States)

    Sack, David A; Shimko, Janet; Torres, Olga; Bourgeois, August L; Francia, Domingo Sanchez; Gustafsson, Björn; Kärnell, Anders; Nyquist, Iréne; Svennerholm, Ann-Mari

    2007-05-30

    We tested the efficacy of a killed oral vaccine for enterotoxigenic Escherichia coli (ETEC) diarrhoea to determine if two doses of vaccine with colonization factor antigens (CF) and cholera B subunit would protect against ETEC diarrhoea of travellers. Six hundred seventy-two healthy travellers going to Mexico or Guatemala were studied in a prospective, randomised, placebo-controlled trial. The primary outcome was a vaccine preventable outcome (VPO), defined as an episode of ETEC diarrhoea with an ETEC organism producing heat labile toxin (LT) or CF homologous with the vaccine, without other known causes. The vaccine was safe and stimulated anti-heat labile toxin antibodies. There was a significant decrease in more severe VPO episodes (PE=77%, p=0.039) as defined by symptoms that interfered with daily activities or more than five loose stools in a day, although the total number of VPO events did not differ significantly in the vaccine and placebo groups. We conclude that the new oral ETEC vaccine reduces the rate of more severe episodes of traveller's diarrhoea (TD) due to VPO-ETEC, but it did not reduce the overall rate of ETEC diarrhoea or of travellers' diarrhoea due to other causes.

  11. Sulfasalazine Attenuates Staphylococcal Enterotoxin B-Induced Immune Responses

    Directory of Open Access Journals (Sweden)

    Teresa Krakauer

    2015-02-01

    Full Text Available Staphylococcal enterotoxin B (SEB and related exotoxins are important virulence factors produced by Staphylococcus aureus as they cause human diseases such as food poisoning and toxic shock. These toxins bind directly to cells of the immune system resulting in hyperactivation of both T lymphocytes and monocytes/macrophages. The excessive release of proinflammatory cytokines from these cells mediates the toxic effects of SEB. This study examined the inhibitory activities of an anti-inflammatory drug, sulfasalazine, on SEB-stimulated human peripheral blood mononuclear cells (PBMC. Sulfasalazine dose-dependently inhibited tumor necrosis factor α, interleukin 1 (IL-1 β, IL-2, IL-6, interferon γ (IFNγ, and various chemotactic cytokines from SEB-stimulated human PBMC. Sulfasalazine also potently blocked SEB-induced T cell proliferation and NFκB activation. These results suggest that sulfasalazine might be useful in mitigating the toxic effects of SEB by blocking SEB-induced host inflammatory cascade and signaling pathways.

  12. The staphylococcal enterotoxin (SE) family: SEB and siblings.

    Science.gov (United States)

    Krakauer, Teresa; Stiles, Bradley G

    2013-11-15

    Staphylococcus aureus plays an important role in numerous human cases of food poisoning, soft tissue, and bone infections, as well as potentially lethal toxic shock. This common bacterium synthesizes various virulence factors that include staphylococcal enterotoxins (SEs). These protein toxins bind directly to major histocompatibility complex class II on antigen-presenting cells and specific Vβ regions of T-cell receptors, resulting in potentially life-threatening stimulation of the immune system. Picomolar concentrations of SEs ultimately elicit proinflammatory cytokines that can induce fever, hypotension, multi-organ failure, and lethal shock. Various in vitro and in vivo models have provided important tools for studying the biological effects of, as well as potential vaccines/therapeutics against, the SEs. This review succinctly presents known physical and biological properties of the SEs, including various intervention strategies. In particular, SEB will often be portrayed as per biodefense concerns dating back to the 1960s.

  13. Suppression of colorectal tumorigenesis by recombinant Bacteroides fragilis enterotoxin-2 in vivo.

    Science.gov (United States)

    Lv, You; Ye, Tao; Wang, Hui-Peng; Zhao, Jia-Ying; Chen, Wen-Jie; Wang, Xin; Shen, Chen-Xia; Wu, Yi-Bin; Cai, Yuan-Kun

    2017-01-28

    To evaluate the impact of recombinant Bacteroides fragilis enterotoxin-2 (BFT-2, or Fragilysin) on colorectal tumorigenesis in mice induced by azoxymethane/dextran sulfate sodium (AOM/DSS). Recombinant proBFT-2 was expressed in Escherichia coli strain Rosetta (DE3) and BFT-2 was obtained and tested for its biological activity via colorectal adenocarcinoma cell strains SW-480. Seventy C57BL/6J mice were randomly divided into a blank (BC; n = 10), model (AD; n = 20), model + low-dose toxin (ADLT; n = 20, 10 μg), and a model + high-dose toxin (ADHT; n = 20, 20 μg) group. Mice weight, tumor formation and pathology were analyzed. Immunohistochemistry determined Ki-67 and Caspase-3 expression in normal and tumor tissues of colorectal mucosa. Recombinant BFT-2 was successfully obtained, along with its biological activity. The most obvious weight loss occurred in the AD group compared with the ADLT group (21.82 ± 0.68 vs 23.23 ± 0.91, P ADHT group (21.82 ± 0.68 vs 23.57 ± 1.06, P ADHT groups (19.75 ± 3.30 vs 6.50 ± 1.73, P ADHT group. The incidence of colorectal adenocarcinoma in both the ADHT group and the ADHT group was reduced compared to that in the AD group ( P ADHT group was 50% and 40%, respectively, both of which were lower than that found in the AD group (94.44%, P ADHT group was 45% and 55%, both of which were higher than that found in the BC group (16.67%, P < 0.05, P < 0.05). Oral administration with lower-dose biologically active recombinant BFT-2 inhibited colorectal tumorigenesis in mice.

  14. Effect of Sodium Chloride and pH on Enterotoxin C Production

    Science.gov (United States)

    Genigeorgis, Constantin; Foda, Mohamed S.; Mantis, Antony; Sadler, Walter W.

    1971-01-01

    Growth and production of enterotoxin C by Staphylococcus aureus strain 137 in 3% + 3% protein hydrolysate powder N-Z Amine NAK broths with 0 to 12% NaCl and an initial pH of 4.00 to 9.83 were studied during an 8-day incubation period at 37 C. Growth was initiated at pH values as low as 4.00 and as high as 9.83 at 0% salt level as long as the inoculum contained at least 108 cells per ml. Rate of growth decreased as the NaCl concentration was increased gradually to 12%. Enterotoxin C was produced in broths inoculated with 108 cells per ml and above and having initial pH ranges of 4.00 to 9.83, 4.40 to 9.43, 4.50 to 8.55 and respective NaCl concentrations of 0, 4, and 8%. In the presence of 10% NaCl, the pH range supporting enterotoxin C production was 5.45 to 7.30 for an inoculum level of 108 cells per ml and 6.38 to 7.30 for 3.6 × 106 cells per ml. In repeated experiments in which the inoculum contained 108 cells per ml, we failed to demonstrate enterotoxin C production in broths with 12% NaCl and a pH range of 4.50 to 8.55 and concentrated up to 14 times. The effect of NaCl on enterotoxin C production followed the same pattern as its effect on enterotoxin B production. As the concentration of NaCl increased from 0 to 10%, yields of enterotoxin B and C decreased to undetectable amounts. PMID:5574320

  15. Purification of heat labile toxin from Bordetella pertussis vaccine ...

    African Journals Online (AJOL)

    K.C. Shivanandappa

    2015-06-23

    Jun 23, 2015 ... heat inactivation at 56 °C for 30 min during Wcpv prepara- tion. Therefore, the ... The B2 culture medium was prepared with following composi- tions: Bacto casamino ... 15min at the ambient temperature (+18 to 22 °C). The.

  16. Purification of heat labile toxin from Bordetella pertussis vaccine ...

    African Journals Online (AJOL)

    . pertussis vaccine strain 134 by employing indigenous technology and examining the immuno-biochemical aspects of the purified protein. Materials and methods: Shaker cultivation of B. pertussis strain 134, sterility, opacity confirmation, TCA ...

  17. E. Coli

    Science.gov (United States)

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

  18. Staphylococcus aureus growth and enterotoxin production in different types of milk

    Directory of Open Access Journals (Sweden)

    Bohdana Janštová, Jr.

    2012-01-01

    Full Text Available The aim of our study was to assess Staphylococcus aureus growth and the time of first detection of staphylococcal enterotoxins type A, B and C (SEA, SEB, SEC in different type of milk, depending on the strain and storage conditions. Raw, pasteurized, and UHT milk were inoculated with three strains of S. aureus, and growth patterns were determined by the plate method in accordance with EN ISO 6888-1. Baird-Parker agar medium was used for the detection of S. aureus and the Enzyme Linked Fluorescent Assay (ELFA used with a miniVIDAS analyzer tested the production of staphylococcal enterotoxins. The results of model experiments showed the dependence of the growth rate and subsequent production of staphylococcal enterotoxins on incubation (storage temperature, S. aureus strain, and type of milk. A significant finding was that the growth of S. aureus and production of enterotoxins in raw milk was inhibited by natural microflora, and production of enterotoxins was therefore not detected in raw milk within 102 hours of storage either at 15 °C or 22 °C. The highest risk of SEs production is associated with secondary contamination of pasteurized and UHT milk when stored at room temperature, where production was first detected after 12 hours of incubation.

  19. Staphylococcus aureus Enterotoxin A Gene Isolated From Raw Red Meat and Poultry in Tehran, Iran

    Directory of Open Access Journals (Sweden)

    Mohammad Hossein Sarrafzadeh Zargar

    2014-07-01

    Full Text Available Background: Staphylococcus aureus is the most prevalent infectious agent of food materials. Enterotoxin producing types of S. aureus cause well-known food-borne disease. Staphylococcal Enterotoxin A (SEA is the most important agent of gastroenteritis. Objectives: The present study aimed to screen the raw meat samples collected from different regions of Tehran for S. aureus infection and type of encoding enterotoxin. Materials and Methods: Hundred and eighty six meat samples were collected randomly from city dealers and transferred to laboratory within screw cap containers. The samples were first cultured according to the standard bacteriological methods and then S. aureus isolates were identified using standard bacteriological tests. The isolates were subjected to Polymerase Chain Reaction (PCR to detect gene encoding SEA. Results: Staphylococcus aureus isolated from 29 (15.6% meat samples including beef 14.8%, raw lamb 15%, raw chicken 15.7% and raw turkey 16.6%. Using special primer sets proved that the species isolated from five samples (two raw chicken, two raw beef and one raw turkey encoded enterotoxin A. Conclusions: Although staphylococcal contamination within food material is more or less a routine, but detection of enterotoxin encoding species from raw meat samples is alarming for health authorities. These data highlight the importance of periodic surveillance of raw meat distributed among ordinary consumers.

  20. Sub-inhibitory stress with essential oil affects enterotoxins production and essential oil susceptibility in Staphylococcus aureus.

    Science.gov (United States)

    Turchi, Barbara; Mancini, Simone; Pistelli, Luisa; Najar, Basma; Cerri, Domenico; Fratini, Filippo

    2018-03-01

    Fourteen wild strains of Staphylococcus aureus positive for gene sea were tested for enterotoxins production and the minimum inhibitory concentration of Leptospermum scoparium, Origanum majorana, Origanum vulgare, Satureja montana and Thymus vulgaris essential oils (EOs) were determined. After this trial, bacteria stressed with sub-inhibitory concentration of each EO were tested for enterotoxins production by an immunoenzymatic assay and resistance to the same EO. Oregano oil exhibited the highest antibacterial activity followed by manuka and thyme oils. After the exposure to a sub-inhibitory concentration of EOs, strains displayed an increased sensitivity in more than 95% of the cases. After treatment with oregano and marjoram EOs, few strains showed a modified enterotoxins production, while 43% of the strains were no longer able to produce enterotoxins after treatment with manuka EO. The results obtained in this study highlight that exposure to sub-inhibitory concentration of EO modifies strains enterotoxins production and EOs susceptibility profile.

  1. Pilot study of whole-blood gamma interferon response to the Vibrio cholerae toxin B subunit and resistance to enterotoxigenic Escherichia coli-associated diarrhea.

    Science.gov (United States)

    Flores, Jose; DuPont, Herbert L; Paredes-Paredes, Mercedes; Aguirre-Garcia, M Magdalena; Rojas, Araceli; Gonzalez, Alexei; Okhuysen, Pablo C

    2010-05-01

    Enterotoxigenic Escherichia coli (ETEC), which produces heat-labile toxin (LT), is a common cause of travelers' diarrhea (TD). The B subunit of ETEC LT is immunologically related to the B subunit of Vibrio cholerae toxin (CT). In this pilot study we evaluated the whole-blood gamma interferon response to CT B in 17 U.S. adults traveling to Mexico. Only one of nine subjects who demonstrated a cellular immune response as determined by whole-blood gamma interferon production to CT B on arrival to Mexico developed diarrhea, whereas five of eight without a cellular response developed diarrhea. Markers of the cellular immune response to ETEC LT could help in identifying individuals immune to ETEC LT, and these markers deserve additional study.

  2. Organ Culture as a Model System for Studies on Enterotoxin Interactions with the Intestinal Epithelium

    DEFF Research Database (Denmark)

    Lorenzen, Ulver Spangsberg; Hansen, Gert H; Danielsen, E Michael

    2015-01-01

    Studies on bacterial enterotoxin-epithelium interactions require model systems capable of mimicking the events occurring at the molecular and cellular levels during intoxication. In this chapter, we describe organ culture as an often neglected alternative to whole-animal experiments or enterocyte......-like cell lines. Like cell culture, organ culture is versatile and suitable for studying rapidly occurring events, such as enterotoxin binding and uptake. In addition, it is advantageous in offering an epithelium with more authentic permeability/barrier properties than any cell line, as well...

  3. Bystander Host Cell Killing Effects of Clostridium perfringens Enterotoxin

    Directory of Open Access Journals (Sweden)

    Archana Shrestha

    2016-12-01

    Full Text Available Clostridium perfringens enterotoxin (CPE binds to claudin receptors, e.g., claudin-4, and then forms a pore that triggers cell death. Pure cultures of host cells that do not express claudin receptors, e.g., fibroblasts, are unaffected by pathophysiologically relevant CPE concentrations in vitro. However, both CPE-insensitive and CPE-sensitive host cells are present in vivo. Therefore, this study tested whether CPE treatment might affect fibroblasts when cocultured with CPE-sensitive claudin-4 fibroblast transfectants or Caco-2 cells. Under these conditions, immunofluorescence microscopy detected increased death of fibroblasts. This cytotoxic effect involved release of a toxic factor from the dying CPE-sensitive cells, since it could be reproduced using culture supernatants from CPE-treated sensitive cells. Supernatants from CPE-treated sensitive cells, particularly Caco-2 cells, were found to contain high levels of membrane vesicles, often containing a CPE species. However, most cytotoxic activity remained in those supernatants even after membrane vesicle depletion, and CPE was not detected in fibroblasts treated with supernatants from CPE-treated sensitive cells. Instead, characterization studies suggest that a major cytotoxic factor present in supernatants from CPE-treated sensitive cells may be a 10- to 30-kDa host serine protease or require the action of that host serine protease. Induction of caspase-3-mediated apoptosis was found to be important for triggering release of the cytotoxic factor(s from CPE-treated sensitive host cells. Furthermore, the cytotoxic factor(s in these supernatants was shown to induce a caspase-3-mediated killing of fibroblasts. This bystander killing effect due to release of cytotoxic factors from CPE-treated sensitive cells could contribute to CPE-mediated disease.

  4. Effects of Bile Acids and Nisin on the Production of Enterotoxin by Clostridium perfringens in a Nutrient-Rich Medium

    Directory of Open Access Journals (Sweden)

    Miseon Park

    2018-01-01

    Full Text Available Clostridium perfringens is the second most common cause of bacterial foodborne illness in the United States, with nearly a million cases each year. C. perfringens enterotoxin (CPE, produced during sporulation, damages intestinal epithelial cells by pore formation, which results in watery diarrhea. The effects of low concentrations of nisin and bile acids on sporulation and toxin production were investigated in C. perfringens SM101, which carries an enterotoxin gene on the chromosome, in a nutrient-rich medium. Bile acids and nisin increased production of enterotoxin in cultures; bile acids had the highest effect. Both compounds stimulated the transcription of enterotoxin and sporulation-related genes and production of spores during the early growth phase. They also delayed spore outgrowth and nisin was more inhibitory. Bile acids and nisin enhanced enterotoxin production in some but not all other C. perfringens isolates tested. Low concentrations of bile acids and nisin may act as a stress signal for the initiation of sporulation and the early transcription of sporulation-related genes in some strains of C. perfringens, which may result in increased strain-specific production of enterotoxin in those strains. This is the first report showing that nisin and bile acids stimulated the transcription of enterotoxin and sporulation-related genes in a nutrient-rich bacterial culture medium.

  5. Effects of Bile Acids and Nisin on the Production of Enterotoxin by Clostridium perfringens in a Nutrient-Rich Medium.

    Science.gov (United States)

    Park, Miseon; Rafii, Fatemeh

    2018-01-01

    Clostridium perfringens is the second most common cause of bacterial foodborne illness in the United States, with nearly a million cases each year. C. perfringens enterotoxin (CPE), produced during sporulation, damages intestinal epithelial cells by pore formation, which results in watery diarrhea. The effects of low concentrations of nisin and bile acids on sporulation and toxin production were investigated in C. perfringens SM101, which carries an enterotoxin gene on the chromosome, in a nutrient-rich medium. Bile acids and nisin increased production of enterotoxin in cultures; bile acids had the highest effect. Both compounds stimulated the transcription of enterotoxin and sporulation-related genes and production of spores during the early growth phase. They also delayed spore outgrowth and nisin was more inhibitory. Bile acids and nisin enhanced enterotoxin production in some but not all other C. perfringens isolates tested. Low concentrations of bile acids and nisin may act as a stress signal for the initiation of sporulation and the early transcription of sporulation-related genes in some strains of C. perfringens , which may result in increased strain-specific production of enterotoxin in those strains. This is the first report showing that nisin and bile acids stimulated the transcription of enterotoxin and sporulation-related genes in a nutrient-rich bacterial culture medium.

  6. Production of enterotoxins of Staphylococcus spp. isolated from samples of sheep milk

    Directory of Open Access Journals (Sweden)

    František Zigo

    2014-02-01

    Full Text Available In our study was followed occurrence of mastitis in herd of 430 sheep of breed zoslachtena valaska with hand milking technology examined two times during one lactation season. Individual examination consisted from clinical examination of udder and microbiological examination of milk samples. By PCR was determined presence of genes coding production of enterotoxins, and by ELISA methods production individual types of enterotoxins. From individual forms of mastitis were frequently detected subacute (6.7%, subclinical (5.7% and acute (2.9%. The coagulase-negative staphylococci (CNS were identified in 102 (65.4% from all 156 positive isolates. The CNS and S. aureus caused subacute (5.1%, subclinical (3.9% and acute (2.4% forms of mastitis. The most frequently isolated were S. epidermidis, followed by S. chromogenes and S. xylosus from ewes with subacute and subclinical mastitis. From acute and chronical forms of mastitis were  predominantly isolated S. aureus, S. uberis and S. epidermidis. The production of staphylococcal enterotoxins (SE - SEA, SEB, SEC, SED and the presence of genes sec (3, sea (2, seb (2 and sed (2 were determined in S. aureus, S. epidermidis, S. schleiferi and S. chromogenes, respectively. The results suggested on the high occurrence (12.4% of subacute and subclinical forms. Confirmed production of enterotoxins and presence of genes coding their production present a risk for human health and decreased a quality of milk and products from sheep´s milk.

  7. Lung and pharyngeal abscess caused by enterotoxin G- and I-producing Staphylococcus aureus.

    Science.gov (United States)

    Barnett, S Y; Hattotuwa, K L; Teare, L

    2012-05-01

    We report a particularly serious case of extensive meticillin sensitive Staphylococcal lung and pharyngeal abscess. Our patient had no significant risk factors for severe infection. The detection of enterotoxin G and I here suggest that when present together, these toxins work synergistically to produce a more virulent strain of Staphylococcus aureus. Copyright © 2011. Published by Elsevier Ltd.

  8. Lab-on-a-chip for label free biological semiconductor analysis of Staphylococcal Enterotoxin B

    NARCIS (Netherlands)

    Yang, Minghui; Sun, Steven; Bruck, Hugh Alan; Kostov, Yordan; Rasooly, Avraham

    2010-01-01

    We describe a new lab-on-a-chip (LOC) which utilizes a biological semiconductor (BSC) transducer for label free analysis of Staphylococcal Enterotoxin B (SEB) (or other biological interactions) directly and electronically. BSCs are new transducers based on electrical percolation through a

  9. Inhibitory effect of totarol on exotoxin proteins hemolysin and enterotoxins secreted by Staphylococcus aureus.

    Science.gov (United States)

    Shi, Ce; Zhao, Xingchen; Li, Wenli; Meng, Rizeng; Liu, Zonghui; Liu, Mingyuan; Guo, Na; Yu, Lu

    2015-10-01

    Staphylococcus aureus (S. aureus) causes a wide variety of infections, which are of major concern worldwide. S. aureus produces multiple virulence factors, resulting in food infection and poisoning. These virulence factors include hyaluronidases, proteases, coagulases, lipases, deoxyribonucleases and enterotoxins. Among the extracellular proteins produced by S. aureus that contribute to pathogenicity, the exotoxins α-hemolysin, staphylococcal enterotoxin A (SEA) and staphylococcal enterotoxin B (SEB) are thought to be of major significance. Totarol, a plant extract, has been revealed to inhibit the proliferation of several pathogens effectively. However, there are no reports on the effects of totarol on the production of α-hemolysin, SEA or SEB secreted by S. aureus. The aim of this study was to evaluate the effects of totarol on these three exotoxins. Hemolysis assay, western blotting and real-time reverse transcriptase-PCR assay were performed to identify the influence of graded subinhibitory concentrations of totarol on the production of α-hemolysin and the two major enterotoxins, SEA and SEB, by S. aureus in a dose-dependent manner. Moreover, an enzyme linked immunosorbent assay showed that the TNF-α production of RAW264.7 cells stimulated by S. aureus supernatants was inhibited by subinhibitory concentrations of totarol. Form the data, we propose that totarol could potentially be used as a promising natural compound in the food and pharmaceutical industries.

  10. Rauvolfia grandiflora (Apocynaceae extract interferes with staphylococcal density, enterotoxin production and antimicrobial activity

    Directory of Open Access Journals (Sweden)

    Lanamar de Almeida Carlos

    2010-10-01

    Full Text Available Staphylococci bacteria are involved in many human and animal infections and development of alternative antimicrobial drugs against pathogenic bacteria is of great interest to the pharmaceutical industry. This study investigated the in vitro effect of Rauvolfia grandiflora methanol extract (root bark fraction (RGE on the density of ATCC strains of Staphylococcus aureus and Staphylococcus epidermidis, and a clinical enterotoxin-producer, S. aureus bovine strain. The alkaloid, isoreserpiline, obtained from dichloromethane extract of R. grandiflora was ineffective against the strains tested. After incubation of staphylococci strains in the presence of 1.2 mg.mL-1 RGE, a significant inhibition of cell growth was observed using both spectrophotometry and ELISA assays. Twelve drugs were evaluated for their antimicrobial effects on culture RGE-treated cells using the disk diffusion method. Penicillin resistant strains became sensitive to the drug after RGE treatment. Furthermore, enterotoxin production by RGE-treated S. aureus was evaluated using a standardized ELISA method. Although staphylococcal LSA 88 bovine strain cells remained viable after exposure to the extract, enterotoxin production was precluded in 20% after RGE treatment. Significant interference in staphylococci cell density, drug sensitivity and enterotoxin secretion was observed after treatment. The study highlights the necessity to find new methods of disease prevention and new antibiotic therapies against staphylococcal infections.

  11. Rauvolfia grandiflora (apocynaceae) extract interferes with staphylococcal density, enterotoxin production and antimicrobial activity.

    Science.gov (United States)

    de Almeida Carlos, Lanamar; da Silva Amaral, Kenas Aguiar; Curcino Vieira, Ivo José; Mathias, Leda; Braz-Filho, Raimundo; Silva Samarão, Solange; Vieira-da-Motta, Olney

    2010-07-01

    Staphylococci bacteria are involved in many human and animal infections and development of alternative antimicrobial drugs against pathogenic bacteria is of great interest to the pharmaceutical industry. This study investigated the in vitro effect of Rauvolfia grandiflora methanol extract (root bark fraction) (RGE) on the density of ATCC strains of Staphylococcus aureus and Staphylococcus epidermidis, and a clinical enterotoxin-producer, S. aureus bovine strain. The alkaloid, isoreserpiline, obtained from dichloromethane extract of R. grandiflora was ineffective against the strains tested. After incubation of staphylococci strains in the presence of 1.2 μg.mL(-1) RGE, a significant inhibition of cell growth was observed using both spectrophotometry and ELISA assays. Twelve drugs were evaluated for their antimicrobial effects on culture RGE-treated cells using the disk diffusion method. Penicillin resistant strains became sensitive to the drug after RGE treatment. Furthermore, enterotoxin production by RGE-treated S. aureus was evaluated using a standardized ELISA method. Although staphylococcal LSA 88 bovine strain cells remained viable after exposure to the extract, enterotoxin production was precluded in 20% after RGE treatment. Significant interference in staphylococci cell density, drug sensitivity and enterotoxin secretion was observed after treatment. The study highlights the necessity to find new methods of disease prevention and new antibiotic therapies against staphylococcal infections.

  12. Expression of Staphylococcal Enterotoxins under Stress Encountered during Food Production and Preservation.

    Science.gov (United States)

    Schelin, Jenny; Susilo, Yusak Budi; Johler, Sophia

    2017-12-15

    Staphylococcal food poisoning (SFP) is the most prevalent cause of food-borne intoxications worldwide. Consumption of enterotoxins preformed in food causes violent vomiting and can be fatal in children and the elderly. While being repressed by competing bacteria in most matrices, Staphylococcus aureus benefits from crucial competitive advantages in foods with high osmolarity or low pH. During recent years, the long-standing belief in the feasibility of assessing SFP risk based on colony-forming units of S. aureus present in food products has been disproven. Instead, researchers and food business operators are acutely aware of the imminent threat arising from unforeseeable enterotoxin production under stress conditions. This paradigm shift led to a variety of new publications enabling an improved understanding of enterotoxin expression under stress conditions encountered in food. The wealth of data provided by these studies is extremely diverse, as it is based on different methodological approaches, staphylococcal strains, stressors, and enterotoxins. Therefore, in this review, we aggregated and critically evaluated the complex findings of these studies, to provide readers with a current overview of the state of research in the field.

  13. The olive compound 4-hydroxytyrosol inactivates Staphyloccoccus aureus bacteria and Staphylococcal enterotoxin A (SEA)

    Science.gov (United States)

    The foodborne pathogen Staphylococcus aureus produces the virulent staphylococcal enterotoxin A (SEA), a single chain protein which consists of 233 amino acid residues with a molecular weight of 27,078 Da. SEA is a superantigen that is reported to contribute to animal (mastitis) and human (emesis, ...

  14. The fecal presence of enterotoxin and F4 genes as an indicator of efficacy of treatment with colistin sulfate in pigs.

    Science.gov (United States)

    Rhouma, Mohamed; Fairbrother, John Morris; Thériault, William; Beaudry, Francis; Bergeron, Nadia; Laurent-Lewandowski, Sylvette; Letellier, Ann

    2017-01-05

    Enterotoxigenic Escherichia coli (ETEC) strains producing multiple enterotoxins are important causes of post-weaning diarrhea (PWD) in pigs. The aim of the present study was to investigate the fecal presence of ETEC enterotoxin as well as F4 and F18 genes as an indicator of colistin sulfate (CS) efficacy for treatment of PWD in pigs. Forty-eight piglets were weaned at the age of 21 days, and were divided into four groups: challenged treated, challenged untreated, unchallenged treated, and unchallenged untreated. Challenge was performed using 10 9  CFU of an ETEC: F4 strain, and treatment was conducted using oral CS at the dose of 50,000 IU/kg. The fecal presence of genes encoding for STa, STb, LT, F4 and F18 was detected using PCR. The PCR amplification of ETEC virulence genes showed that nearly 100% of pigs excreted genes encoding for STa and STb toxins in the feces before the challenge. These genes, in the absence of the gene encoding F4, were considered as a marker for F4-negative ETEC. One day after ETEC: F4 oral challenge pigs in the two challenged groups excreted the genes encoding LT and F4 in the feces. These genes were considered as a marker for F4-positive ETEC. However, the gene encoding F18 was not detected in any fecal samples of the 4 groups throughout the experiment. After only 3 days of successive oral treatment with CS, a significant reduction in both the F4-positive and negative ETEC populations was observed in the challenged treated group compared to the challenged untreated group (p F4-positive and F4-negative ETEC in pigs. However, CS clinical efficiency was correlated with non-detection of F4-positive ETEC in the feces. Furthermore the fecal presence of F4-negative ETEC was not associated with clinical symptoms of post-weaning diarrhea in pigs.

  15. Antidiarrhoeal activity of different plants used in traditional medicine

    African Journals Online (AJOL)

    SERVER

    2007-12-28

    Dec 28, 2007 ... components such as artificial sweeteners and lactose and the result is the .... decrease in severe diarrhoea of rats treated with castor oil. This extract also ..... heat-labile enterotoxin and ganglioside interaction. J. Ethnopharma-.

  16. [Enterotoxin genes occurance among S. aureus strains isolated from inpatients and carriers].

    Science.gov (United States)

    Lawrynowicz-Paciorek, Maja; Kochman, Maria; Piekarska, Katarzyna; Wyrebiak, Agata; Potracka, Ewa; Leniak-Chmiel, Urszula; Magdziak, Agnieszka

    2006-01-01

    We examined 44 inpatients and 66 carriers Staphylococcus aureus strains, isolated in years 2002-2005, for the presence of 18 enterotoxin genes (se/sel) (by PCR), the ability for A-D enterotoxin production (by SET-RPLA) and antibiotic resistance distribution (by disc diffusion method). se/sel genes were detected in 90,9% of all strains, sea (70,5%) and selk and selq (52,3%) - among inpatients strains and egc (65,2%) - among carriers strains were the most frequently se/sel genes found. Positive results of SET-RPLA were consistent with PCR results. There was no correlation observed between antibiotic resistance and se/sel genes distribution among tested S. aureus strains.

  17. Prevalence of Staphylococcal Enterotoxins in Ready-to-Eat Foods Sold in Istanbul.

    Science.gov (United States)

    Ulusoy, Beyza H; Çakmak Sancar, Burcu; Öztürk, Muhsin

    2017-10-01

    The aim of this study was to investigate the prevalence of staphylococcal enterotoxins (SEs) in ready-to-eat (RTE) foods sold in Istanbul, Turkey. A total of 5,241 samples were randomly collected from various caterers, hotels, and restaurants from 2014 to 2016. The samples were classified into four groups: (i) various cooked RTE meat and vegetable meals, (ii) various RTE salads, charcuterie, and cold appetizers, (iii) various cooked RTE bakery products (pasta, pastries, pizza, pita, ravioli, etc.), and (iv) any cooked RTE sweets and desserts (pudding, custard, cream, ashura, etc.). The samples were examined for the presence of SEs by 3M Tecra Staph Enterotoxin Visual Immunoassay method, which is a manual enzyme-linked immunosorbent assay method. Among all samples, only 1 (0.019%) RTE meal (vegetable meal with meat) was found to be contaminated with SEs, a good result in terms of staphylococcal food poisoning risk and public health.

  18. The influence of radiation on the enterotoxin and thermoresistant deoxyribo-nuclease production by Staphylococcus sp

    International Nuclear Information System (INIS)

    Szulc, M.; Pliszka, A.; Peconek, J.

    1980-01-01

    Six strains of Staph. aureus present in the environment with and without protein were exposed to X rays in the doses range from 1 to 400 Gy. The production of enterotoxin and thermoresistant deoxyribonuclease by enterotoxic strains No 262 and 100 was determined. All the strains showed similar radiosensitivity to X rays. About 1 per cent of protein in the environment exposed to radiation increased the resistance of Staphylococcus strains. The doses of radiation from 1 to 400 Gy did not influence the enterotoxin A and B production by bacteria multiplied from those which had survived the radiation. The irradiation of the strains present in the environment without protein brought about a temporary inhibition of thermoresistant deoxyribonuclease production. (author)

  19. Selection and characterization of DNA aptamers against Staphylococcus aureus enterotoxin C1.

    Science.gov (United States)

    Huang, Yukun; Chen, Xiujuan; Duan, Nuo; Wu, Shijia; Wang, Zhouping; Wei, Xinlin; Wang, Yuanfeng

    2015-01-01

    Enterotoxins from pathogenic bacteria are known as the main reason that can cause the bacterial foodborne diseases. In this study, aptamers that bound to Staphylococcus aureus enterotoxin C1 (SEC1) with high affinity and selectivity were generated in vitro by twelve rounds of selection based on magnetic separation technology, with a low-level dissociation constant (Kd) value of 65.14 ± 11.64 nmol/L of aptamer C10. Aptamer-based quantification of SEC1 in the food sample by a graphene oxide (GO)-based method was implemented to investigate the potential of the aptamer against SEC1 with a limit of detection of 6 ng/mL. On the basis of this work, biosensors using the selected SEC1 aptamers as new molecular recognition elements could be applied for innovative determinations of SEC1. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. PCR detection of staphylococcal enterotoxin genes in Staphylococcus aureus strains isolated from raw and pasteurized milk.

    Science.gov (United States)

    Rall, V L M; Vieira, F P; Rall, R; Vieitis, R L; Fernandes, A; Candeias, J M G; Cardoso, K F G; Araújo, J P

    2008-12-10

    Milk is considered a nutritious food because it contains several important nutrients including proteins and vitamins. Conversely, it can be a vehicle for several pathogenic bacteria such as Staphylococcus aureus. This study aimed to analyze the frequency of genes encoding the staphylococcal enterotoxins (SEs) SEA, SEB, SEC, SED, SEE, SEG, SEH, SEI and SEJ in S. aureus strains isolated from raw or pasteurized bovine milk. S. aureus was found in 38 (70.4%) out of 54 raw milk samples at concentrations of up to 8.9 x 10(5) CFU/ml. This microorganism was present in eight samples of pasteurized milk before the expiration date and in 11 samples analyzed on the expiration date. Of the 57 strains studied, 68.4% were positive for one or more genes encoding the enterotoxins, and 12 different genotypes were identified. The gene coding for enterotoxin A, sea, was the most frequent (16 strains, 41%), followed by sec (8 strains, 20.5%), sed (5 strains, 12.8%), seb (3 strains, 7.7%) and see (2 strains, 5.1%). Among the genes encoding the other enterotoxins, seg was the most frequently observed (11 strains, 28.2%), followed by sei (10 strains) and seh and sej (3 strains each). With the recent identification of new SEs, the perceived frequency of enterotoxigenic strains has increased, suggesting that the pathogenic potential of staphylococci may be higher than previously thought; however, further studies are required to assess the expression of these new SEs by S. aureus, and their impact in foodborne disease. The quality of Brazilian milk is still low, and efforts from the government and the entire productive chain are required to attain consumer safety.

  1. Antibiotic resistance and enterotoxin genes in Staphylococcus sp. isolates from polluted water in Southern Brazil

    OpenAIRE

    BASSO, ANA P.; MARTINS, PAULA D.; NACHTIGALL, GISELE; SAND, SUELI VAN DER; MOURA, TIANE M. DE; FRAZZON, ANA PAULA G.

    2014-01-01

    The aim of this study was to evaluate the species distribution, antibiotic-resistance profile and presence of enterotoxin (SE) genes in staphylococci isolated from the Dilúvio stream in South Brazil. Eighty-eight staphylococci were identified, 93.18% were identified as coagulase-negative (CNS) and 6.82% coagulase-positive (CPS). Fourteen Staphylococcus species were detected and the most frequently were Staphylococcus cohnii (30.48%) and S. haemolyticus (21.95%). Resistance to erythromycin was...

  2. A Single-Stranded DNA Aptamer That Selectively Binds to Staphylococcus aureus Enterotoxin B

    OpenAIRE

    DeGrasse, Jeffrey A.

    2012-01-01

    The bacterium Staphylococcus aureus is a common foodborne pathogen capable of secreting a cocktail of small, stable, and strain-specific, staphylococcal enterotoxins (SEs). Staphylococcal food poisoning (SFP) results when improperly handled food contaminated with SEs is consumed. Gastrointestinal symptoms of SFP include emesis, diarrhea and severe abdominal pain, which manifest within hours of ingesting contaminated food. Immuno-affinity based methods directly detect, identify, and quantify s...

  3. Putative new heat-stable cytotoxic and enterotoxic factors in culture supernatant of Escherichia coli isolated from drinking water

    Directory of Open Access Journals (Sweden)

    DA Ribeiro

    2011-01-01

    Full Text Available Enteric infections caused by the ingestion of contaminated water, especially by Escherichia coli, are important to define the virulence properties of these bacteria. Due to frequent infantile diarrhea in the city of Ouro Preto, Minas Gerais state, Brazil, the phenotypic and genotypic diarrheagenic properties of E. coli isolated from drinking water were studied. The culture supernatants of 39 (40% among a total of 97 E. coli isolates from drinking water were positive by suckling mouse assay and induced cytotoxic effects on Vero cells. The enterotoxic and cytotoxic activities were present in the fraction with less than 10 kDa and were not lost when heated up to 60°C and 100°C for 30 minutes. PCR assays showed that among these 39 Vero cytotoxigenic E. coli, four (10.2% were positive for ST II (estB and two (5% positive for αHly (hlyA. Gene amplification of SLT (stx 1, stx 2, ST I (estA, LT (eltI, eltII, EAST1 (astA, EHly (enhly and plasmid-encoded enterotoxin (pet were not observed. This heat-stable cytotoxic enterotoxin of E. coli is probably a new putative diarrheagenic virulence factor, as a toxin presenting these characteristics has not yet been described.

  4. Effects of frozen storage on survival of Staphylococcus aureus and enterotoxin production in precooked tuna meat.

    Science.gov (United States)

    Wu, Xulei; Su, Yi-Cheng

    2014-08-01

    This study investigated the survival of Staphylococcus aureus in precooked tuna meat for producing canned products during frozen storage (-20 ± 2 °C) as well as its growth and enterotoxin production at 35 to 37 °C after the storage. Samples (50 ± 5 g) of precooked albacore (loin, chunk, and flake) and skipjack (chunk and flake) tuna were inoculated with 5 enterotoxin-producing strains of S. aureus at a level of approximately 3.5 log CFU/g and individually packed in a vacuum bag after 3 h incubation at 35 to 37 °C. Vacuum-packed samples were stored in a freezer (-20 ± 2 °C) for 4 wk. The frozen samples were then thawed in 37 °C circulating water for 2 h and incubated at 35 to 37 °C for 22 h. Populations of S. aureus in all precooked tuna samples decreased slightly (canned tuna within 6 to 8 h of thawing to avoid product spoilage and potential enterotoxin production by S. aureus in contaminated precooked tuna meat. © 2014 Institute of Food Technologists®

  5. Staphylococcal superantigens; toxic shock syndrome toxin-1 and enterotoxins in pediatric otitis media effusion: a brief report

    Directory of Open Access Journals (Sweden)

    Noorbakhsh S

    2013-03-01

    Full Text Available Background: Staphylococcal superantigens (SAg's may have some role in otitis media with effusion (OME. The aim of this study was the search of staphylococcal SAg's in middle ear effusion of children with OME.  Methods: This cross sectional-analytic study was done in ENT & pediatric wards upon 64 children with otitis media with effusion (OME between 1-15 years, (mean age=7.42+4 years of Rasoul Akram University Hospital, Tehran, Iran in 2009-2011. Fifty six percent (36 of cases were male, 43.8% (28 were female. Staphylococcal SAg's; Toxic Shock Syndrome Toxin-1 (TSST-1, Staphylococcal enterotoxin A, B, C, D (Enzyme immune assay, AB Cam, USA were detected in middle ear effusion samples after conventional culture.Results: None type of SAg's found in 39% of OME cases, enterotoxin B found in: 22%; enterotoxin A: 17%, enterotoxin C: 15.6%, enterotoxin D: 12.5%, Toxic Shock Syndrome Toxin-1 (TSST-1: 7.8% Mean age of cases with positive TSST-1, enterotoxin A, B, C, and D was: 1, 5, 8.6, 9.6 and 9.6 years respectively. Positive TSST had no agreement with positive enterotoxin A and C but had weak agreement with type B and D. Mean age of cases with positive TSST was one years which had significant difference with (7.9 years in cases with negative TSST test (P<0.0001.Conclusion: At least one or more type of staphylococcal toxins had found in middle ear effusion of 70% of OME cases with negative culture for Staphylococcus aureus. Even in culture negative cases, staphylococcal toxins might have some immunologic role in middle ear effusion forming. Finding the SAg's (at least one type are important for treatment of immunosuppressive or corticosteroid in cases with resistant OME.

  6. Detection of virulence genes and the phylogenetic groups of Escherichia coli isolated from dogs in Brazil

    Directory of Open Access Journals (Sweden)

    Fernanda Morcatti Coura

    2018-02-01

    Full Text Available ABSTRACT: This study identified the virulence genes, pathovars, and phylogenetic groups of Escherichia coli strains obtained from the feces of dogs with and without diarrhea. Virulence genes and phylogenetic group identification were studied using polymerase chain reaction. Thirty-seven E. coli isolates were positive for at least one virulence factor gene. Twenty-one (57.8% of the positive isolates were isolated from diarrheal feces and sixteen (43.2% were from the feces of non-diarrheic dogs. Enteropathogenic E. coli (EPEC were the most frequently (62.2% detected pathovar in dog feces and were mainly from phylogroup B1 and E. Necrotoxigenic E. coli were detected in 16.2% of the virulence-positive isolates and these contained the cytotoxic necrotizing factor 1 (cnf1 gene and were classified into phylogroups B2 and D. All E. coli strains were negative for the presence of enterotoxigenic E. coli (ETEC enterotoxin genes, but four strains were positive for ETEC-related fimbriae 987P and F18. Two isolates were Shiga toxin-producing E. coli strains and contained the toxin genesStx2 or Stx2e, both from phylogroup B1. Our data showed that EPEC was the most frequent pathovar and B1 and E were the most common phylogroups detected in E. coli isolated from the feces of diarrheic and non-diarrheic dogs.

  7. Escherichia Coli

    Science.gov (United States)

    Goodsell, David S.

    2009-01-01

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

  8. Outbreaks of cholera-like diarrhoea caused by enterotoxigenic Escherichia coli in the Brazilian Amazon Rainforest.

    Science.gov (United States)

    Vicente, Ana C P; Teixeira, Luiz F M; Iniguez-Rojas, L; Luna, M G; Silva, L; Andrade, J R C; Guth, B E C

    2005-09-01

    The relationship between enteropathogens and severe diarrhoea in the Brazilian Amazon is poorly understood. In 1998, outbreaks of acute diarrhoea clinically diagnosed as cholera occurred in two small villages localized far from the main cholera route in the Brazilian rainforest. PCR was performed on some enteropathogens and heat-labile (LT) and/or heat-stable (STh) toxin genes, the virulence determinants of enterotoxigenic Escherichia coli (ETEC), were detected. Further characterization of ETEC isolates revealed the presence of two clones, one from each outbreak. One presenting serotype O167:H5 harboured LT-I and STh toxin genes and expressed the CS5CS6 colonization factor. The other, a non-typeable serotype, was positive for the LT-I gene and expressed the CS7 colonization factor. The current study demonstrates the importance of molecular diagnosis in regions such as the Amazon basin, where the enormous distances and local support conditions make standard laboratory diagnosis difficult. Here we also show that the mis-identified cholera cases were in fact associated with ETEC strains. This is the first report of ETEC, molecularly characterized as the aetiological agent of severe diarrhoea in children and adults in the Brazilian Amazon Rainforest.

  9. Effect of low-dose gamma irradiation on enterotoxin-positive strains of Clostridium perfringens Type A

    International Nuclear Information System (INIS)

    Barnhart, H.M. Jr.

    1976-01-01

    The effect of low-dose gamma irradiation on selected enterotoxin producing strains of Clostridium perfringens Type A was studied. The radioresistance of three strains NCTC-8239, NCTC-10239 and NCTC-8798 in 0.1 percent peptone water, beef gravy and ground beef was determined for both vegetative cells and spores. D 10 values were approximately 30 Krad in 0.1 percent peptone water and 175 Krad in beef menstruums. D 10 values for spores were approximately 250 Krad in 0.1 percent peptone water and 335 Krad in beef. Low-level irradiation induced a 2 hr lag for cell recovery at 37 0 C following irradiation though this was strain dependent. Heat resistance of vegetative cells decreased following irradiation, although one strain was stimulated in growth response and unaltered in its heat resistance. Spore activation and germination were not affected by low-level irradiation. Spores were not significantly inactivated at this level. Irradiation had no effect on subsequent survival of vegetative cells stored at cold temperatures. Enterotoxin production by irradiated cultures was not affected by the irradiation treatment. A method for quantitating C. perfringens enterotoxin using crossed-immunoelectrophoresis was developed. It was found that this technique could detect at least .05 g of enterotoxin, could utilize crude enterotoxin preparations and was more sensitive than other methods based on biological activity

  10. Effects of tetrodotoxin and ion replacements on the short-circuit current induced by Escherichiacoli heat stable enterotoxin across small intestine of the gerbil (Gerbillus cheesmani

    Directory of Open Access Journals (Sweden)

    Fawzia Yaqoub Al-Balool

    2004-03-01

    Full Text Available The effects of mucosally added Escherichia coli heat stable enterotoxin (STa 30 ng ml-1 on the basal short-circuit current (Isc in µA cm-2 across stripped and unstripped sheets of jejuna and ilea taken from fed, starved (4 days, water ad lib and undernourished (50% control food intake for 21 days gerbil (Gerbillus cheesmani were investigated. The effect of neurotoxin tetrodotoxin (TTX 10 µM and the effects of replacing chloride by gluconate or the effects of removing bicarbonate from bathing buffers on the maximum increase in Isc induced by STa were also investigated. The maximum increase in Isc which resulted from the addition of STa were significantly higher in jejuna and ilea taken from starved and undernourished gerbils when compared with the fed control both using stripped and unstripped sheets. In the two regions of the small intestine taken from fed and starved animals TTX reduced the maximum increase in Isc induced by STa across unstripped sheets only. Moreover in jejuna and ilea taken from undernourished gerbils TTX reduced significantly the maximum increase in Isc induced by STa across stripped and unstripped sheets. Replacing chloride by gluconate decreased the maximum increase in Isc induced by STa across jejuna and ilea taken from undernourished gerbils only. Removing bicarbonates from bathing buffer decreased the maximum increase in Isc across the jejuna and ilea taken from starved and undernourished gerbils.

  11. A complex array of Hpr consensus DNA recognition sequences proximal to the enterotoxin gene in Clostridium perfringens type A.

    Science.gov (United States)

    Brynestad, S; Iwanejko, L A; Stewart, G S; Granum, P E

    1994-01-01

    Enterotoxin production in Clostridium perfringens is both strain dependent and sporulation associated. Underlying these phenotypic observations must lie a genetic and molecular explanation and the principal keys will be held within the DNA sequence both upstream and downstream of the structural gene cpe. In accordance with the above we have sequenced 4.1 kbp of DNA upstream of cpe in the type strain NCTC 8239. A region of DNA extending up to 1.5 kb 5' to cpe is conserved in all enterotoxin-positive strains. This region contains a putative ORF with substantial homology to an ORF in the Salmonella typhimurium IS200 insertion element and, in addition, contains multiple perfect consensus DNA-binding sequences for the Bacillus subtilis transition state regulator Hpr. The detailed structural elements revealed by the sequence analysis are presented and used to develop a new perspective on the molecular basis of enterotoxin production in this important food-poisoning bacterium.

  12. How do the rotavirus NSP4 and bacterial enterotoxins lead differently to diarrhea?

    Directory of Open Access Journals (Sweden)

    Vasseur Monique

    2007-03-01

    Full Text Available Abstract Rotavirus is the major cause of infantile gastroenteritis and each year causes 611 000 deaths worldwide. The virus infects the mature enterocytes of the villus tip of the small intestine and induces a watery diarrhea. Diarrhea can occur with no visible tissue damage and, conversely, the histological lesions can be asymptomatic. Rotavirus impairs activities of intestinal disaccharidases and Na+-solute symports coupled with water transport. Maldigestion of carbohydrates and their accumulation in the intestinal lumen as well as malabsorption of nutrients and a concomitant inhibition of water reabsorption can lead to a malabsorption component of diarrhea. Since the discovery of the NSP4 enterotoxin, diverse hypotheses have been proposed in favor of an additional secretion component in the pathogenesis of diarrhea. Rotavirus induces a moderate net chloride secretion at the onset of diarrhea, but the mechanisms appear to be quite different from those used by bacterial enterotoxins that cause pure secretory diarrhea. Rotavirus failed to stimulate Cl- secretion in crypt, whereas it stimulated Cl- reabsorption in villi, questioning, therefore, the origin of net Cl- secretion. A solution to this riddle was that intestinal villi do in fact secrete chloride as a result of rotavirus infection. Also, the overall chloride secretory response is regulated by a phospholipase C-dependent calcium signaling pathway induced by NSP4. However, the overall response is weak, suggesting that NSP4 may exert both secretory and subsequent anti-secretory actions, as did carbachol, hence limiting Cl- secretion. All these characteristics provide the means to make the necessary functional distinction between viral NSP4 and bacterial enterotoxins.

  13. Uncoupling of T Cell Receptor Zeta Chain Function during the Induction of Anergy by the Superantigen, Staphylococcal Enterotoxin A

    Directory of Open Access Journals (Sweden)

    William D. Cornwell

    2010-06-01

    Full Text Available Staphylococcus aureus enterotoxins have immunomodulatory properties. In this study, we show that Staphylococcal enterotoxin A (SEA induces a strong proliferative response in a murine T cell clone independent of MHC class II bearing cells. SEA stimulation also induces a state of hypo-responsiveness (anergy. We characterized the components of the T cell receptor (TCR during induction of anergy by SEA. Most interestingly, TCR zeta chain phosphorylation was absent under SEA anergizing conditions, which suggests an uncoupling of zeta chain function. We characterize here a model system for studying anergy in the absence of confounding costimulatory signals.

  14. Plant-Derived Polyphenols Interact with Staphylococcal Enterotoxin A and Inhibit Toxin Activity

    OpenAIRE

    Shimamura, Yuko; Aoki, Natsumi; Sugiyama, Yuka; Tanaka, Takashi; Murata, Masatsune; Masuda, Shuichi

    2016-01-01

    This study was performed to investigate the inhibitory effects of 16 different plant-derived polyphenols on the toxicity of staphylococcal enterotoxin A (SEA). Plant-derived polyphenols were incubated with the cultured Staphylococcus aureus C-29 to investigate the effects of these samples on SEA produced from C-29 using Western blot analysis. Twelve polyphenols (0.1-0.5 mg/mL) inhibited the interaction between the anti-SEA antibody and SEA. We examined whether the polyphenols could directly i...

  15. Cloning Sequencing and Structural Manipulation of the Enterotoxin D and E Genes from Staphylococcus aureus

    Science.gov (United States)

    1990-07-01

    Iandolo, J.J. and R.K. Tweten. 1988. Purification of staphylococcal enterotoxin. In. Methods of Enzymology, (N.O. Kaplan , S. Harshman, Eds.) volume 165...N C V 9 L G 0 K 1 S P A K I C T S N 0 149 "T7AACTGG&&C&hICG&clhht:7caflCATGTAATAa~aI ACca CAACaCAA 942 L K D G D K L Z L I G T P r D H K V N 0 H L..L

  16. Elevated Enterotoxin A Expression and Formation in Staphylococcus aureus and Its Association with Prophage Induction

    OpenAIRE

    Cao, Rong; Zeaki, Nikoleta; Wallin-Carlquist, Nina; Skandamis, Panagiotis N.; Schelin, Jenny; Rådström, Peter

    2012-01-01

    Staphylococcus aureus strains producing the bacteriophage-encoded staphylococcal enterotoxin A (SEA) were divided into two groups, high- and low-SEA-producing strains, based on the amount of SEA produced. After growth under favorable conditions in batch cultures, 10 of the 21 strains tested produced more than 1,000 ng/ml SEA, and 9 strains produced less than 10 ng/ml SEA; two enterotoxigenic strains, MRSA252 and Newman, produced intermediate levels of SEA (around 450 ng/ml). The differences i...

  17. E. Coli and Pregnancy

    Science.gov (United States)

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

  18. E coli enteritis

    Science.gov (United States)

    ... coli; Food poisoning - E. coli; E. coli diarrhea; Hamburger disease ... coleslaw or potato salad) that have been out of the refrigerator too ... reheated Fish or oysters Raw fruits or vegetables that have ...

  19. Characterization of Enterotoxigenic Bacillus cereus sensu lato and Staphylococcus aureus Isolates and Associated Enterotoxin Production Dynamics in Milk or Meat-Based Broth.

    Science.gov (United States)

    Walker-York-Moore, Laura; Moore, Sean C; Fox, Edward M

    2017-07-15

    Bacillus cereus sensu lato species, as well as Staphylococcus aureus , are important pathogenic bacteria which can cause foodborne illness through the production of enterotoxins. This study characterised enterotoxin genes of these species and examined growth and enterotoxin production dynamics of isolates when grown in milk or meat-based broth. All B. cereus s. l. isolates harboured nheA , hblA and entFM toxin genes, with lower prevalence of bceT and hlyII . When grown at 16 °C, toxin production by individual B. cereus s. l. isolates varied depending on the food matrix; toxin was detected at cell densities below 5 log 10 (CFU/mL). At 16 °C no staphylococcal enterotoxin C (SEC) production was detected by S. aureus isolates, although low levels of SED production was noted. At 30 °C all S. aureus isolates produced detectable enterotoxin in the simulated meat matrix, whereas SEC production was significantly reduced in milk. Relative to B. cereus s. l. toxin production, S. aureus typically required reaching higher cell numbers to produce detectable levels of enterotoxin. Phylogenetic analysis of the sec and sel genes suggested population evolution which correlated with animal host adaptation, with subgroups of bovine isolates or caprine/ovine isolates noted, which were distinct from human isolates. Taken together, this study highlights the marked differences in the production of enterotoxins both associated with different growth matrices themselves, but also in the behaviour of individual strains when exposed to different food matrices.

  20. Cell-to-cell transformation in Escherichia coli: a novel type of natural transformation involving cell-derived DNA and a putative promoting pheromone.

    Directory of Open Access Journals (Sweden)

    Rika Etchuuya

    Full Text Available Escherichia coli is not assumed to be naturally transformable. However, several recent reports have shown that E. coli can express modest genetic competence in certain conditions that may arise in its environment. We have shown previously that spontaneous lateral transfer of non-conjugative plasmids occurs in a colony biofilm of mixed E. coli strains (a set of a donor strain harbouring a plasmid and a plasmid-free recipient strain. In this study, with high-frequency combinations of strains and a plasmid, we constructed the same lateral plasmid transfer system in liquid culture. Using this system, we demonstrated that this lateral plasmid transfer was DNase-sensitive, indicating that it is a kind of transformation in which DNase-accessible extracellular naked DNA is essential. However, this transformation did not occur with purified plasmid DNA and required a direct supply of plasmid from co-existing donor cells. Based on this feature, we have termed this transformation type as 'cell-to-cell transformation'. Analyses using medium conditioned with the high-frequency strain revealed that this strain released a certain factor(s that promoted cell-to-cell transformation and arrested growth of the other strains. This factor is heat-labile and protease-sensitive, and its roughly estimated molecular mass was between ∼9 kDa and ∼30 kDa, indicating that it is a polypeptide factor. Interestingly, this factor was effective even when the conditioned medium was diluted 10(-5-10(-6, suggesting that it acts like a pheromone with high bioactivity. Based on these results, we propose that cell-to-cell transformation is a novel natural transformation mechanism in E. coli that requires cell-derived DNA and is promoted by a peptide pheromone. This is the first evidence that suggests the existence of a peptide pheromone-regulated transformation mechanism in E. coli and in Gram-negative bacteria.

  1. Role of Enterotoxin-Producing Staphylococci in Zoonotic Infections in Iran

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    Abdolmajid Ghasemian

    2018-05-01

    Full Text Available Context: Staphylococci spp, are enterotoxin-producing zoonotic agents causing a variety of infections such as mastitis in animals and wound bite infections in humans. This review was conducted to determine the prevalence of Staphylococci infections especially to uncover enterotoxin-producing species in Iran. Evidence acquisition: for this review, words of "Staphylococcus", "zoonotic", "prevalence", "animals", "human" and "Iran" were searched in the internet engines such as Google Scholar, PubMed, Google, Science Direct and so on. Patients with no history of contact with animals were also included in the study for comparison aims. Both veterinary and human coagulase positive isolates were included. Data was analyzed with Graph Pad Prism 6, meta-analysis section. A total of 20 previous studies (450 clinical samples were found. S. intermedius was the predominant isolate identified in veterinary sources. Other coagulase positive spp such as S. hycus and S. simulans were isolated with lower prevalence, but S. delphini has not been detected. Conclusion: S. intermedius was the most isolate identified in veterinary sources with potential of causing infections in humans. Other coagulase positive spp such as S. hycus and S. simulans were isolated with lower prevalence, but S. delphini was not detected.

  2. Detection of enterotoxins and genotyping of Staphylococcus aureus strains isolated from Isfahan Educational Hospital, Iran

    Directory of Open Access Journals (Sweden)

    Seyed Asghar Havaei

    2017-10-01

    Full Text Available Background and aims: Staphylococcus aureus is known as one of the most important nosocomial pathogens, which may lead to several infections. The aim of this study was determining the enterotoxins A, C, and TSST-1 and molecular characterization of S. aureus strains with PFGE and MLST typing methods. Materials and methods: In the present study during the sixmonths sampling, fifty S. aureus strains were isolated from patients admitted to Al-Zahra university hospital. Antimicrobial susceptibility testing, Multiplex PCR for detection of enterotoxin A, C and TSST-1, pulse field gel electrophoresis (PFGE and multilocus sequence typing (MLST were used for molecular typing. Results: In antibiogram the highest and lowest percentage of resistance was belonged to tetracycline and rifampin respectively. Multiplex PCR indicated that 30% of the strains harbored sea and 34% harbored sec genes. However, only 4% of our collected isolates had tsst gene. In PFGE method analysis on all S. aureus strains, a total of 19 different patterns were identified. Nine various sequence types in 27 selected S. aureus isolates were identified by MLST. Conclusions: Present study indicates a possible higher variability among our S. aureus strains by two different molecular typing methods; nevertheless four main common types (CT1, CT7, CT9, and CT11 with at least one toxin genes were determined.

  3. Antibiotic resistance and enterotoxin genes in Staphylococcus sp. isolates from polluted water in Southern Brazil.

    Science.gov (United States)

    Basso, Ana P; Martins, Paula D; Nachtigall, Gisele; Van Der Sand, Sueli; De Moura, Tiane M; Frazzon, Ana Paula G

    2014-12-01

    The aim of this study was to evaluate the species distribution, antibiotic-resistance profile and presence of enterotoxin (SE) genes in staphylococci isolated from the Dilúvio stream in South Brazil. Eighty-eight staphylococci were identified, 93.18% were identified as coagulase-negative (CNS) and 6.82% coagulase-positive (CPS). Fourteen Staphylococcus species were detected and the most frequently were Staphylococcus cohnii (30.48%) and S. haemolyticus (21.95%). Resistance to erythromycin was verified in 37.50% of the strains, followed by 27.27% to penicillin, 12.50% to clindamycin, 6.81% to trimethoprim-sulfamethoxazole, 5.68% to chloramphenicol and 2.27% to norfloxacin. None of the investigated strains showed gentamicin and ciprofloxacin resistance. The strains were tested for the presence of sea, seb, sec, sed and see genes by PCR and only CNS strains (43.18%) showed positive results to one or more SE genes. The scientific importance of our results is due to the lack of data about these topics in polluted waters in Brazil. In conclusion, polluted waters from the Dilúvio stream may constitute a reservoir for disseminating antibiotic-resistance and enterotoxin into the community. In addition, the detection of staphylococci in the polluted waters of the Dilúvio stream indicated a situation of environmental contamination and poor sanitation conditions.

  4. Antibiotic resistance and enterotoxin genes in Staphylococcus sp. isolates from polluted water in Southern Brazil

    Directory of Open Access Journals (Sweden)

    ANA P. BASSO

    2014-12-01

    Full Text Available The aim of this study was to evaluate the species distribution, antibiotic-resistance profile and presence of enterotoxin (SE genes in staphylococci isolated from the Dilúvio stream in South Brazil. Eighty-eight staphylococci were identified, 93.18% were identified as coagulase-negative (CNS and 6.82% coagulase-positive (CPS. Fourteen Staphylococcus species were detected and the most frequently were Staphylococcus cohnii (30.48% and S. haemolyticus (21.95%. Resistance to erythromycin was verified in 37.50% of the strains, followed by 27.27% to penicillin, 12.50% to clindamycin, 6.81% to trimethoprim-sulfamethoxazole, 5.68% to chloramphenicol and 2.27% to norfloxacin. None of the investigated strains showed gentamicin and ciprofloxacin resistance. The strains were tested for the presence of sea, seb, sec, sed and see genes by PCR and only CNS strains (43.18% showed positive results to one or more SE genes. The scientific importance of our results is due to the lack of data about these topics in polluted waters in Brazil. In conclusion, polluted waters from the Dilúvio stream may constitute a reservoir for disseminating antibiotic-resistance and enterotoxin into the community. In addition, the detection of staphylococci in the polluted waters of the Dilúvio stream indicated a situation of environmental contamination and poor sanitation conditions.

  5. Staphylococcal enterotoxins in the Etiopathogenesis of Mucosal Autoimmunity within the Gastrointestinal Tract

    Directory of Open Access Journals (Sweden)

    MaryAnn Principato

    2014-04-01

    Full Text Available The staphylococcal enterotoxins (SEs are the products of Staphylococcus aureus and are recognized as the causative agents of classical food poisoning in humans following the consumption of contaminated food. While illness evoked by ingestion of the SE or its producer organism in tainted food are often self-limited, our current understanding regarding the evolution of S. aureus provokes the utmost concern. The organism and its associated toxins, has been implicated in a wide variety of disease states including infections of the skin, heart, sinuses, inflammatory gastrointestinal disease, toxic shock, and Sudden Infant Death Syndrome. The intricate relationship between the various subsets of immunocompetent T cells and accessory cells and the ingested material found within the gastrointestinal tract present daunting challenges to the maintenance of immunologic homeostasis. Dysregulation of the intricate balances within this environment has the potential for extreme consequences within the host, some of which are long-lived. The focus of this review is to evaluate the relevance of staphylococcal enterotoxin in the context of mucosal immunity, and the underlying mechanisms that contribute to the pathogenesis of gastrointestinal autoimmune disease.

  6. Contamination of beef products with staphylococcal classical enterotoxins in Egypt and Saudi Arabia

    Directory of Open Access Journals (Sweden)

    Shawish, Reyad R.

    2016-04-01

    Full Text Available Food-borne pathogens are of high concern for public health and food safety. food poisoning is one of the most economically devastating types of food poisoning globally. The purpose of this study was to detect staphylococcal classical enterotoxins (SEs in processed beef from Kingdom of Saudi Arabia (KSA and Egypt. In the present investigation a total of 250 random processed meat samples (50 each of minced meat, beef burger, beef sausage, beef kofta and beef luncheon were collected from different super markets in the study area. Using conventional cultural methods, samples were cultured for isolation and identification of . Multiplex PCR was used to detect SEs of the classical type SEA, SEB, SEC and SED from isolates.The percentage presence of in minced meat, beef burger, beef sausage, beef kofta and beef luncheon was 38%, 22%, 30%, 32% and 12%, respectively. Multiplex PCR indicated that all examined samples contain different types of classical staphylococcal enterotoxins and only minced meat samples contained all four types of toxins. Multiplex PCR is efficient in detection of SEs from food and may be used in tracing of toxins to promote food hygiene. Implications of contamination of processed meat to food hygiene in the study area are highlighted.

  7. A probability model for enterotoxin production of Bacillus cereus as a function of pH and temperature

    Science.gov (United States)

    Bacillus cereus is frequently isolated from a variety of foods including vegetables, dairy products, meat, and other raw and processed foods. The bacterium is capable of producing enterotoxin and emetic toxin that can cause severe nausea, vomiting and diarrhea. The objectives of this study were to a...

  8. Comparative analysis of antimicrobial resistance in enterotoxigenic Escherichia coli isolates from two paediatric cohort studies in Lima, Peru.

    Science.gov (United States)

    Medina, Anicia M; Rivera, Fulton P; Pons, Maria J; Riveros, Maribel; Gomes, Cláudia; Bernal, María; Meza, Rina; Maves, Ryan C; Huicho, Luis; Chea-Woo, Elsa; Lanata, Claudio F; Gil, Ana I; Ochoa, Theresa J; Ruiz, Joaquim

    2015-08-01

    Antibiotic resistance is increasing worldwide, being of special concern in low- and middle-income countries. The aim of this study was to determine the antimicrobial susceptibility and mechanisms of resistance in 205 enterotoxigenic Escherichia coli (ETEC) isolates from two cohort studies in children Peru. ETEC were identified by an in-house multiplex real-time PCR. Susceptibility to 13 antimicrobial agents was tested by disk diffusion; mechanisms of resistance were evaluated by PCR. ETEC isolates were resistant to ampicillin (64%), cotrimoxazole (52%), tetracycline (37%); 39% of the isolates were multidrug-resistant. Heat-stable toxin producing (ETEC-st) (48%) and heat-labile toxin producing ETEC (ETEC-lt) (40%) had higher rates of multidrug resistance than isolates producing both toxins (ETEC-lt-st) (21%), pPeru. However, further development of resistance should be closely monitored. Published by Oxford University Press on behalf of Royal Society of Tropical Medicine and Hygiene 2015. This work is written by (a) US Government employee(s) and is in the public domain in the US.

  9. 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

  10. 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...

  11. Claudins Overexpression in Ovarian Cancer: Potential Targets for Clostridium Perfringens Enterotoxin (CPE Based Diagnosis and Therapy

    Directory of Open Access Journals (Sweden)

    Diana P. English

    2013-05-01

    Full Text Available Claudins are a family of tight junction proteins regulating paracellular permeability and cell polarity with different patterns of expression in benign and malignant human tissues. There are approximately 27 members of the claudin family identified to date with varying cell and tissue-specific expression. Claudins-3, -4 and -7 represent the most highly differentially expressed claudins in ovarian cancer. While their exact role in ovarian tumors is still being elucidated, these proteins are thought to be critical for ovarian cancer cell invasion/dissemination and resistance to chemotherapy. Claudin-3 and claudin-4 are the natural receptors for the Clostridium perfringens enterotoxin (CPE, a potent cytolytic toxin. These surface proteins may therefore represent attractive targets for the detection and treatment of chemotherapy-resistant ovarian cancer and other aggressive solid tumors overexpressing claudin-3 and -4 using CPE-based theranostic agents.

  12. Staphylococcal enterotoxin C2 promotes osteogenesis and suppresses osteoclastogenesis of human mesenchymal stem cells.

    Science.gov (United States)

    Fu, Wei-ming; Zhu, Xiao; Wang, Hua; Wei-Mao Wang; Chen, Ju-yu; Liang, Yan; Zhang, Jin-fang; Kung, Hsiang-fu

    2014-03-10

    As a super-antigen, staphylococcal enterotoxin C2 (SEC2) stimulates the release of massive inflammatory cytokines such as interferon-gamma (IFN-γ), interleukin-1 (IL-1) and interleukin-2 (IL-2) which are documented to implicate osteoblast differentiation. In the present study, SEC2 was found to significantly improve the osteoblast differentiation by up-regulating BMP2 and Runx2/Cbfa1 expression. Interferon (IFN)-inducible gene IFI16, a co-activator of Runx2/Cbfa1, was also activated by SEC2 in the osteoblast differentiation. In addition, exogenous introduction of SEC2 stimulated OPG expression and suppressed RANKL, suggesting suppression of osteoclastogenesis in hMSCs. Therefore, our results displayed that SEC2 plays an important role in the commitment of MSC to the osteoblast and it might be a potential new therapeutic candidate for bone regeneration. Copyright © 2013 Elsevier Inc. All rights reserved.

  13. Identification and Characterization of a New Enterotoxin Produced by Clostridium perfringens Isolated from Food Poisoning Outbreaks.

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    Daisuke Irikura

    Full Text Available There is a strain of Clostridium perfringens, W5052, which does not produce a known enterotoxin. We herein report that the strain W5052 expressed a homologue of the iota-like toxin components sa and sb of C. spiroforme, named Clostridium perfringens iota-like enterotoxin, CPILE-a and CPILE-b, respectively, based on the results of a genome sequencing analysis and a systematic protein screening. In the nicotinamide glyco-hydrolase (NADase assay the hydrolysis activity was dose-dependently increased by the concentration of rCPILE-a, as judged by the mass spectrometry analysis. In addition, the actin monomer of the lysates of Vero and L929 cells were radiolabeled in the presence of [32P]NAD and rCPILE-a. These findings indicated that CPILE-a possesses ADP-ribosylation activity. The culture supernatant of W5052 facilitated the rounding and killing of Vero and L929 cells, but the rCPILE-a or a non-proteolyzed rCPILE-b did not. However, a trypsin-treated rCPILE-b did. Moreover, a mixture of rCPILE-a and the trypsin-treated rCPILE-b enhanced the cell rounding and killing activities, compared with that induced by the trypsin-treated rCPILE-b alone. The injection of the mixture of rCPILE-a and the trypsin-treated rCPILE-b into an ileum loop of rabbits evoked the swelling of the loop and accumulation of the fluid dose-dependently, suggesting that CPILE possesses enterotoxic activity. The evidence presented in this communication will facilitate the epidemiological, etiological, and toxicological studies of C. perfringens food poisoning, and also stimulate studies on the transfer of the toxins' gene(s among the Genus Clostridium.

  14. Comparative Effects of Food Preservatives on the Production of Staphylococcal Enterotoxin I from Staphylococcus aureus Isolate

    Directory of Open Access Journals (Sweden)

    Yanying Zhao

    2017-01-01

    Full Text Available Staphylococcal enterotoxin I (SEI is associated with staphylococcal food poisoning, but little is known about different food preservatives on the production of SEI. In this study, the effect of different food preservatives (sodium nitrite, polylysine, chitosan, and tea catechin on the bacteria growth, sei gene expression, and extracellular SEI production of Staphylococcus aureus isolate H4 was detected in tryptone soya broth (TSB culture. Our results showed that all of these preservatives depressed S. aureus H4 growth and the order of inhibitory effect was 0.8 g/L tea catechin > 6 g/L chitosan > 0.25 g/L polylysine > 0.4 g/L tea catechin > 0.15 g/L sodium nitrite. Furthermore, 0.25 g/L polylysine or 0.15 g/L sodium nitrite did not significantly alter sei gene transcription, while 6 g/L chitosan obviously increased the relative mRNA level of sei gene expression. 0.4 g/L tea catechin remarkably inhibited sei gene transcription. In addition, 0.15 g/L sodium nitrite and 6 g/L chitosan significantly enhanced SEI secretion. 0.25 g/L polylysine, especially 0.4 g/L tea catechin, sharply inhibited the level of SEI secretion. The results indicated that tea catechin not only suppressed Staphylococcus aureus growth, but also inhibited SEI production and secretion, suggesting that tea catechin may be better than sodium nitrite, polylysine, or chitosan for keeping the food from the contamination of SEI. These investigations would be useful for food industry to provide safer food products due to S. aureus enterotoxins-related control strategy.

  15. Detection of Staphylococcus aureus enterotoxins in sheep cheese and dairy desserts by multiplex PCR technique.

    Science.gov (United States)

    Ertas, Nurhan; Gonulalan, Zafer; Yildirim, Yeliz; Kum, Erhan

    2010-08-15

    The aim of this study was to investigate the presence of Staphylococcus aureus (S. aureus) and staphylococcal enterotoxins (SEs) genes in sheep cheese and dairy dessert samples by multiplex PCR (mPCR) technique. A total of 150 samples were analyzed consisting of 50 dairy dessert samples and 100 sheep cheese. Coagulase positive staphylococci (CPS) were found in 86 (57.3%) out of 150 analyzed samples. S. aureus were isolated from 60 (60%), 26 (52%) of sheep cheese and from of dairy desserts, respectively. Five suspected colonies were tested from each sheep cheese and dairy dessert samples for phenotypic and genotypic characterizations. A total of 430 isolates from the 86 positive samples were investigated in this study. Eighty (18.6%) isolates were characterized as S. aureus. The enterotoxin genes (sea, seb, sec, sed) were found in 13 (3.02%) out of 80 isolates. From cheese isolates, sea, seb and sed were detected in 5 (1.6%), 2 (0.6%), 1 (0.3%), respectively. From dairy dessert isolates, sea, sec and sed were detected in 3 (2.3%), 1 (0.76%), 1 (0.76%), respectively. The presence of SEs was identified in 12 (2.8%) out of 80 isolates by using ELISA technique. It was determined that these SEs had a distribution of 7 (1.6%) SEA, 2 (0.46%) SEB, 1 (0.23%) SEC, and 2 (0.46%) SED. SEs were found in 7 (2.3%) cheese and 5 (3.8%) dairy dessert isolates. In conclusion, S.aureus and their SEs were found to be present in sheep cheese and dairy desserts in this study. It is emphasized that the presence of S. aureus and their SEs genes in sheep cheese and dairy desserts may be regarded as a potential risk for human health. Copyright 2010 Elsevier B.V. All rights reserved.

  16. Short communication: Pasteurization as a means of inactivating staphylococcal enterotoxins A, B, and C in milk.

    Science.gov (United States)

    Necidova, Lenka; Bogdanovicova, Katerina; Harustiakova, Danka; Bartova, Katerina

    2016-11-01

    Our aim was to assess the effect of pasteurization temperature on inactivation of staphylococcal enterotoxins (SE). Milk samples were inoculated with log 4.38 to 5.18cfu/mL of 40 different Staphylococcus aureus strains having the ability to produce types A, B, or C SE and incubated at 37°C for 24h to develop SE. This incubation was followed by heat treatment for 15 s at 72, 85, and 92°C. Samples were analyzed for Staph. aureus count by plate method and, specifically, for SE presence. An enzyme-linked immunofluorescent assay on a MiniVIDAS analyzer (bioMérieux, Marcy l'Étoile, France) was used to detect SE, which were determined semiquantitatively based on test values. The Staph. aureus count in milk before pasteurization did not affect the amount of SE. Before pasteurization, SEB was detected in the lowest amount compared with other SE types. Staphylococcal enterotoxins were markedly reduced with pasteurization and inactivated at pasteurization temperatures to an extent depending on the amount in the sample before pasteurization. After pasteurization at 72°C, SE were detected in 87.5% of samples (35/40), after pasteurization at 85°C in 52.5% of samples (21/40), and after pasteurization at 92°C in 45.0% of samples (18/40). We determined that SE may still persist in milk even when Staph. aureus bacteria are inactivated through pasteurization. Although pasteurization may partially inactivate SE in milk, a key measure in the prevention of staphylococcal enterotoxicosis linked to pasteurized milk consumption is to avoid any cold chain disruption during milk production and processing. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  17. A single-stranded DNA aptamer that selectively binds to Staphylococcus aureus enterotoxin B.

    Science.gov (United States)

    DeGrasse, Jeffrey A

    2012-01-01

    The bacterium Staphylococcus aureus is a common foodborne pathogen capable of secreting a cocktail of small, stable, and strain-specific, staphylococcal enterotoxins (SEs). Staphylococcal food poisoning (SFP) results when improperly handled food contaminated with SEs is consumed. Gastrointestinal symptoms of SFP include emesis, diarrhea and severe abdominal pain, which manifest within hours of ingesting contaminated food. Immuno-affinity based methods directly detect, identify, and quantify several SEs within a food or clinical sample. However, the success of these assays depends upon the availability of a monoclonal antibody, the development of which is non-trivial and costly. The current scope of the available immuno-affinity based methods is limited to the classical SEs and does not encompass all of the known or emergent SEs. In contrast to antibodies, aptamers are short nucleic acids that exhibit high affinity and specificity for their targets without the high-costs and ethical concerns of animal husbandry. Further, researchers may choose to freely distribute aptamers and develop assays without the proprietary issues that increase the per-sample cost of immuno-affinity assays. This study describes a novel aptamer, selected in vitro, with affinity to staphylococcal enterotoxin B (SEB) that may be used in lieu of antibodies in SE detection assays. The aptamer, designated APT(SEB1), successfully isolates SEB from a complex mixture of SEs with extremely high discrimination. This work sets the foundation for future aptamer and assay development towards the entire family of SEs. The rapid, robust, and low-cost identification and quantification of all of the SEs in S. aureus contaminated food is essential for food safety and epidemiological efforts. An in vitro generated library of SE aptamers could potentially allow for the comprehensive and cost-effective analysis of food samples that immuno-affinity assays currently cannot provide.

  18. A single-stranded DNA aptamer that selectively binds to Staphylococcus aureus enterotoxin B.

    Directory of Open Access Journals (Sweden)

    Jeffrey A DeGrasse

    Full Text Available The bacterium Staphylococcus aureus is a common foodborne pathogen capable of secreting a cocktail of small, stable, and strain-specific, staphylococcal enterotoxins (SEs. Staphylococcal food poisoning (SFP results when improperly handled food contaminated with SEs is consumed. Gastrointestinal symptoms of SFP include emesis, diarrhea and severe abdominal pain, which manifest within hours of ingesting contaminated food. Immuno-affinity based methods directly detect, identify, and quantify several SEs within a food or clinical sample. However, the success of these assays depends upon the availability of a monoclonal antibody, the development of which is non-trivial and costly. The current scope of the available immuno-affinity based methods is limited to the classical SEs and does not encompass all of the known or emergent SEs. In contrast to antibodies, aptamers are short nucleic acids that exhibit high affinity and specificity for their targets without the high-costs and ethical concerns of animal husbandry. Further, researchers may choose to freely distribute aptamers and develop assays without the proprietary issues that increase the per-sample cost of immuno-affinity assays. This study describes a novel aptamer, selected in vitro, with affinity to staphylococcal enterotoxin B (SEB that may be used in lieu of antibodies in SE detection assays. The aptamer, designated APT(SEB1, successfully isolates SEB from a complex mixture of SEs with extremely high discrimination. This work sets the foundation for future aptamer and assay development towards the entire family of SEs. The rapid, robust, and low-cost identification and quantification of all of the SEs in S. aureus contaminated food is essential for food safety and epidemiological efforts. An in vitro generated library of SE aptamers could potentially allow for the comprehensive and cost-effective analysis of food samples that immuno-affinity assays currently cannot provide.

  19. Passive therapy with humanized anti-staphylococcal enterotoxin B antibodies attenuates systemic inflammatory response and protects from lethal pneumonia caused by staphylococcal enterotoxin B-producing Staphylococcus aureus.

    Science.gov (United States)

    Karau, Melissa J; Tilahun, Mulualem E; Krogman, Ashton; Osborne, Barbara A; Goldsby, Richard A; David, Chella S; Mandrekar, Jayawant N; Patel, Robin; Rajagopalan, Govindarajan

    2017-10-03

    Drugs such as linezolid that inhibit bacterial protein synthesis may be beneficial in treating infections caused by toxigenic Staphylococcus aureus. As protein synthesis inhibitors have no effect on preformed toxins, neutralization of pathogenic exotoxins with anti-toxin antibodies may be beneficial in conjunction with antibacterial therapy. Herein, we evaluated the efficacy of human-mouse chimeric high-affinity neutralizing anti-staphylococcal enterotoxin B (SEB) antibodies in the treatment of experimental pneumonia caused by SEB-producing S. aureus. Since HLA class II transgenic mice mount a stronger systemic immune response following challenge with SEB and are more susceptible to SEB-induced lethal toxic shock than conventional mice strains, HLA-DR3 transgenic mice were used. Lethal pneumonia caused by SEB-producing S. aureus in HLA-DR3 transgenic mice was characterized by robust T cell activation and elevated systemic levels of several pro-inflammatory cytokines and chemokines. Prophylactic administration of a single dose of linezolid 30 min prior to the onset of infection attenuated the systemic inflammatory response and protected from mortality whereas linezolid administered 60 min after the onset of infection failed to confer significant protection. Human-mouse chimeric high-affinity neutralizing anti-SEB antibodies alone, but not polyclonal human IgG, mitigated this response and protected from death when administered immediately after initiation of infection. Further, anti-SEB antibodies as well as intact polyclonal human IgG, but not its Fab or Fc fragments, protected from lethal pneumonia when followed with linezolid therapy 60 min later. In conclusion, neutralization of superantigens with high-affinity antibodies may have beneficial effects in pneumonia.

  20. Inhibitory effects of food additives derived from polyphenols on staphylococcal enterotoxin A production and biofilm formation by Staphylococcus aureus.

    Science.gov (United States)

    Shimamura, Yuko; Hirai, Chikako; Sugiyama, Yuka; Shibata, Masaharu; Ozaki, Junya; Murata, Masatsune; Ohashi, Norio; Masuda, Shuichi

    2017-12-01

    In this study, we examined the inhibitory effects of 14 food additives derived from polyphenol samples on staphylococcal enterotoxin A (SEA) production and biofilm formation by Staphylococcus aureus. Tannic acid AL (TA), Purephenon 50 W (PP) and Polyphenon 70A (POP) at 0.25 mg/mL and Gravinol®-N (GN), Blackcurrant polyphenol AC10 (BP), and Resveratrol-P5 (RT) at 1.0 mg/mL significantly decreased SEA production by S. aureus C-29 (p Food additives derived from polyphenols have viability to be used as a means to inhibit the enterotoxin production and control the biofilm formation of foodborne pathogens.

  1. Effects of nisin and temperature on survival, growth, and enterotoxin production characteristics of psychrotrophic Bacillus cereus in beef gravy.

    OpenAIRE

    Beuchat, L R; Clavero, M R; Jaquette, C B

    1997-01-01

    The presence of psychrotrophic enterotoxigenic Bacillus cereus in ready-to-serve meats and meat products that have not been subjected to sterilization treatment is a public health concern. A study was undertaken to determine the survival, growth, and diarrheal enterotoxin production characteristics of four strains of psychrotrophic B. cereus in brain heart infusion (BHI) broth and beef gravy as affected by temperature and supplementation with nisin. A portion of unheated vegetative cells from...

  2. Characterization of Staphylococcus aureus strains and evidence for the involvement of non-classical enterotoxin genes in food poisoning outbreaks.

    Science.gov (United States)

    Ciupescu, Laurentiu-Mihai; Auvray, Frederic; Nicorescu, Isabela Madalina; Meheut, Thomas; Ciupescu, Veronica; Lardeux, Anne-Laure; Tanasuica, Rodica; Hennekinne, Jacques-Antoine

    2018-06-05

    To an increasing extent, molecular and genetic characterization is now used to investigate foodborne outbreaks. The aim of this study was to seek molecular links among coagulase-positive staphylococci (CPS) isolated from three recent food poisoning outbreaks in Romania using polymerase chain reaction and pulsed-field gel electrophoresis (PFGE) techniques. Nineteen CPS isolates were identified as Staphylococcus aureus by detection of the 23S rDNA gene. Among them, 15 carried at least one staphylococcal enterotoxin-encoding gene (se). The Calarași outbreak strains grouped in pulsotype 2 and were sed/sej/ser-positive, whereas the Arad outbreak strains clustered in pulsotype 17 and were either sed/seg/sei/sej/ser- or seg/sei-positive. The Pitești outbreak strains clustered in pulsotype 1 and, surprisingly, possessed only one enterotoxin gene, i.e. seh. Similar to other European countries, the seh gene has been identified with increasing frequency in Romanian outbreaks; this highlights the importance of considering the application of methods recommended for staphylococcal enterotoxin regulation in Europe.

  3. E. Coli Infections

    Science.gov (United States)

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

  4. Cloned polynucleotide and synthetic oligonucleotide probes used in colony hybridization are equally efficient in the identification of enterotoxigenic Escherichia coli

    International Nuclear Information System (INIS)

    Sommerfelt, H.; Kalland, K.H.; Raj, P.; Moseley, S.L.; Bhan, M.K.; Bjorvatn, B.

    1988-01-01

    Restriction endonuclease-generated polynucleotide and synthetically produced oligonucleotide gene probes used in colony hybridization assays proved to be efficient for the detection and differentiation of enterotoxigenic Escherichia coli. To compare their relative efficiencies, these two sets of probes were radiolabeled with 32 P and were applied to 74 strains of E. coli with known enterotoxin profiles and to 156 previously unexamined E. coli isolates. The enterotoxigenic bacteria Vibrio cholerae O1, Vibrio cholerae non-O1 (NAG), Yersinia enterocolitica, and E. coli harboring the plasmid vectors of the polynucleotide gene probes were examined for further evaluation of probe specificity. The two classes of probes showed a perfect concordance in their specific detection and differentiation of enterotoxigenic E. coli. In the analysis of six strains, the signal strength on autoradiography after hybridization with oligonucleotides was weaker than that obtained after hybridization with polynucleotide probes. The probes did not hybridize with DNA from V. cholerae O1, V. cholerae non-O1 (NAG), or Y. enterocolitica. The strains of E. coli harboring the plasmid vectors of the polynucleotide gene probes were, likewise, negative in the hybridization assays

  5. Cloned polynucleotide and synthetic oligonucleotide probes used in colony hybridization are equally efficient in the identification of enterotoxigenic Escherichia coli

    Energy Technology Data Exchange (ETDEWEB)

    Sommerfelt, H.; Kalland, K.H.; Raj, P.; Moseley, S.L.; Bhan, M.K.; Bjorvatn, B.

    1988-11-01

    Restriction endonuclease-generated polynucleotide and synthetically produced oligonucleotide gene probes used in colony hybridization assays proved to be efficient for the detection and differentiation of enterotoxigenic Escherichia coli. To compare their relative efficiencies, these two sets of probes were radiolabeled with /sup 32/P and were applied to 74 strains of E. coli with known enterotoxin profiles and to 156 previously unexamined E. coli isolates. The enterotoxigenic bacteria Vibrio cholerae O1, Vibrio cholerae non-O1 (NAG), Yersinia enterocolitica, and E. coli harboring the plasmid vectors of the polynucleotide gene probes were examined for further evaluation of probe specificity. The two classes of probes showed a perfect concordance in their specific detection and differentiation of enterotoxigenic E. coli. In the analysis of six strains, the signal strength on autoradiography after hybridization with oligonucleotides was weaker than that obtained after hybridization with polynucleotide probes. The probes did not hybridize with DNA from V. cholerae O1, V. cholerae non-O1 (NAG), or Y. enterocolitica. The strains of E. coli harboring the plasmid vectors of the polynucleotide gene probes were, likewise, negative in the hybridization assays.

  6. Effects of nisin and temperature on survival, growth, and enterotoxin production characteristics of psychrotrophic Bacillus cereus in beef gravy.

    Science.gov (United States)

    Beuchat, L R; Clavero, M R; Jaquette, C B

    1997-05-01

    The presence of psychrotrophic enterotoxigenic Bacillus cereus in ready-to-serve meats and meat products that have not been subjected to sterilization treatment is a public health concern. A study was undertaken to determine the survival, growth, and diarrheal enterotoxin production characteristics of four strains of psychrotrophic B. cereus in brain heart infusion (BHI) broth and beef gravy as affected by temperature and supplementation with nisin. A portion of unheated vegetative cells from 24-h BHI broth cultures was sensitive to nisin as evidenced by an inability to form colonies on BHI agar containing 10 micrograms of nisin/ml. Heat-stressed cells exhibited increased sensitivity to nisin. At concentrations as low as 1 microgram/ml, nisin was lethal to B. cereus, the effect being more pronounced in BHI broth than in beef gravy. The inhibitory effect of nisin (1 microgram/ml) was greater on vegetative cells than on spores inoculated into beef gravy and was more pronounced at 8 degrees C than at 15 degrees C. Nisin, at a concentration of 5 or 50 micrograms/ml, inhibited growth in gravy inoculated with vegetative cells and stored at 8 or 15 degrees C, respectively, for 14 days. Growth of vegetative cells and spores of B. cereus after an initial period of inhibition is attributed to loss of activity of nisin. One of two test strains produced diarrheal enterotoxin in gravy stored at 8 or 15 degrees C within 9 or 3 days, respectively. Enterotoxin production was inhibited in gravy supplemented with 1 microgram of nisin/ml and stored at 8 degrees C for 14 days; 5 micrograms of nisin/ml was required for inhibition at 15 degrees C. Enterotoxin was not detected in gravy in which less than 5.85 log10 CFU of B. cereus/ml had grown. Results indicate that as little as 1 microgram of nisin/ml may be effective in inhibiting or retarding growth of and diarrheal enterotoxin production by vegetative cells and spores of psychrotrophic B. cereus in beef gravy at 8 degrees C, a

  7. CodY Promotes Sporulation and Enterotoxin Production by Clostridium perfringens Type A Strain SM101.

    Science.gov (United States)

    Li, Jihong; Freedman, John C; Evans, Daniel R; McClane, Bruce A

    2017-03-01

    Clostridium perfringens type D strains cause enterotoxemia and enteritis in livestock via epsilon toxin production. In type D strain CN3718, CodY was previously shown to increase the level of epsilon toxin production and repress sporulation. C. perfringens type A strains producing C. perfringens enterotoxin (CPE) cause human food poisoning and antibiotic-associated diarrhea. Sporulation is critical for C. perfringens type A food poisoning since spores contribute to transmission and resistance in the harsh food environment and sporulation is essential for CPE production. Therefore, the current study asked whether CodY also regulates sporulation and CPE production in SM101, a derivative of C. perfringens type A food-poisoning strain NCTC8798. An isogenic codY -null mutant of SM101 showed decreased levels of spore formation, along with lower levels of CPE production. A complemented strain recovered wild-type levels of both sporulation and CPE production. When this result was coupled with the earlier results obtained with CN3718, it became apparent that CodY regulation of sporulation varies among different C. perfringens strains. Results from quantitative reverse transcriptase PCR analysis clearly demonstrated that, during sporulation, codY transcript levels remained high in SM101 but rapidly declined in CN3718. In addition, abrB gene expression patterns varied significantly between codY -null mutants of SM101 and CN3718. Compared to the levels in their wild-type parents, the level of abrB gene expression decreased in the CN3718 codY -null mutant strain but significantly increased in the SM101 codY -null mutant strain, demonstrating CodY-dependent regulation differences in abrB expression between these two strains. This difference appears to be important since overexpression of the abrB gene in SM101 reduced the levels of sporulation and enterotoxin production, supporting the involvement of AbrB repression in regulating C. perfringens sporulation. Copyright © 2017

  8. The Isolation and Detection of Staphylococcus aureus Enterotoxins A-E and TSST-1 Genes from Different Sources by PCR Method

    Directory of Open Access Journals (Sweden)

    Norouzi J

    2012-09-01

    Full Text Available Background and Objectives: Enterotoxins and toxic shock syndrome toxin–1 (TSST-1 are an important virulence factor of S. aureus. The purpose of this study was to analyze the presence of S. aureus enterotoxin (sea-see and tst genes in the samples that collected from different sources with PCR method. Methods: During 5 months from 150 collected samples, 80 strains were identified as S. aureus. PCR reaction was used for investigation on the presence of genes for staphylococcal enterotoxins (A-E and toxic shock syndrome toxin-1 (TSST-1. Results: Fifty three samples (66.25% out of 80 samples were positive for one or more ETs and TSST-1 genes. of these positive strains, 17 (32.07% were positive for sea 39 (73.58% for seb, 30 (56.6% for sec, 2 (3.7% for sed, 21 (39.62% for see, and 14 (26.41% for tst. Enterotoxins and tst in 40 samples (75.47% observed.Conclusion: In this study, high prevalence of S. aureus, its enterotoxin, and tst genes were observed in clinical samples, food samples, and healthy people. This fact emphasizes on the role of human as original source and carrier of S. aureus. Also, use of PCR reaction for detection of these genes in S. aureus that isolated from various sources is recommended.

  9. [Poisoning by enterotoxin from Staphylococcus aureus associated with mocha pastry. Microbiology and epidemiology].

    Science.gov (United States)

    Escartín, E F; Saldaña-Lozano, J; Montiel-Falcón, A

    1998-01-01

    A brief description of a foodborne outbreak due to S. aureus enterotoxin associated with the consumption of mocha cake in the city of Guadalajara is presented. The cake was prepared in a bakery and affected nearly 100 persons. S. aureus was isolated from the nose and skin of one of the pastry cooks. A S. aureus strain isolated from the cake involved in the outbreak was not only unable to grow in the mocha cream, but it actually decreased in numbers by 2 log after 72 h of storage at 30 degrees C. The pH of mocha cream ranged from 6.2 to 6.6, and water activity from 0.833 to 0.859, with a media of 0.841. In preparing mocha cake at the shop, one half of the dough used to be sprayed with a sucrose solution in water (20% w/v); mocha cream was spread on the other half of the dough before overlapping the two halves. When mocha cake was prepared in this manner, and stored at 30 degrees C, S. aureus increased in number by more than 4 log after 48 h. S. aureus did not grow in the cake stored at 4-7 degrees C. Contributory factors in this outbreak were an increase of water activity in the interphase of the mocha and the cake dough, storage of the cake in an unrefrigerated area, and an unusually high ambient temperature (28-32 degrees C) at that time.

  10. Formation of cereulide and enterotoxins by Bacillus cereus in fermented African locust beans

    DEFF Research Database (Denmark)

    Thorsen, Line; Azokpota, Paulin; Munk Hansen, Bjarne

    2011-01-01

    Afitin, iru and sonru are three spontaneously fermented African locust bean Benin condiments. The fermentation processes are exothermic, with temperatures mostly being above 40 °C. A total of 19 predominant Bacillus cereus isolates from afitin, iru and sonru, were investigated. The enterotoxin...... genes nhe (A, B, C) were present in all 19 isolates, the hbl (A, C, D) in one (afitin), and the cytK gene in three isolates (afitin). Levels of cytotoxicity to Vero cells and NheA production in BHI-broth was within the range of known diarrheal outbreak strains. Autoclaved cooked African locust beans...... inoculated with emetic (cereulide producing) B. cereus Ba18H2/RIF supported growth at 25, 30 and 40 °C with highly different maximum cereulide productions of 6 ± 5, 97 ± 3 and 0.04 ± 0.02 μg/g beans, respectively (48 h). For non-autoclaved cooked beans inoculated with 2, 4 and 6 log10 B. cereus Ba18H2/RIF...

  11. Colorimetric determination of staphylococcal enterotoxin B via DNAzyme-guided growth of gold nanoparticles

    International Nuclear Information System (INIS)

    Zhou, Dandan; Chen, Hui; Xie, Guoming; Cao, Xianqing; Chen, Xueping; Zhang, Xing

    2016-01-01

    The authors describe a colorimetric method for the determination of the staphylococcal enterotoxin B (SEB) that also allows for visual readout. The assay is based on the growth of gold nanoparticles (AuNPs) mediated by a hemin/G-quadruplex DNAzyme which generates a color change from red to blue in the presence of SEB. The method is enzyme-free and does not require a label. The kinetics of the formation of the AuNPs is controlled by the hemin/G-quadruplex DNAzyme and this is key to the signal generation mechanism. In the presence of SEB, the reactions between aptamer and target modulated the amount of single probe G strands that form DNAzyme capable of consuming hydrogen peroxide. The growth process of AuNPs is influenced by the resulting concentration of H 2 O 2 and leads to the color change. Under optimal conditions, a linear relationship exists between absorbance and SEB concentration in the range from 0.1 to 500 pg·mL -1 which covers the clinically relevant range. In case of visual detection, the lower limit of detection is 1 pg·mL −1 . The assay described here is sensitive, comparably inexpensive and can detect SEB rapidly without the need for sophisticated equipment. In our perception, the method has a wide scope in that it may be adapted to various nucleic acids, proteins and other biomolecules if respective aptamers are available. (author)

  12. Colorimetric DNAzyme Biosensor for Convenience Detection of Enterotoxin B Harboring Staphylococcus aureus from Food Samples.

    Science.gov (United States)

    Mondal, Bhairab; N, Bhavanashri; Ramlal, Shylaja; Kingston, Joseph

    2018-02-14

    In the present study, a colorimetric DNAzymes biosensor strategy was devised in combination with immunomagnetic separation for rapid and easy detection of enterotoxin B harboring Staphylococcus aureus from food and clinical samples. The method employs immunocapture of S. aureus and amplification of seb gene by DNAzyme complementary sequence integrated forward primer and with specific reverse primer. The DNAzyme sequence integrated dsDNA PCR products when treated with hemin and TMB (3,3',5,5'-tetramethylbenzidine) in the presence of H 2 O 2 produce colorimetric signal. A linear relationship of optical signal with the initial template of seb was obtained which could be monitored by visually or spectrophotrometrically for qualitative and quantitative detection. The limit of detection for the assay was approximately 10 2 CFU/mL of seb gene harboring target. This method is convenient compared to gel based and ELISA systems. Further, spiking studies and analysis on natural samples emphasized the robustness and applicability of developed method. Altogether, the established assay could be a reliable alternative, low-cost, viable detection tool for the routine investigation of seb from food and clinical sources.

  13. Plant-Derived Polyphenols Interact with Staphylococcal Enterotoxin A and Inhibit Toxin Activity.

    Science.gov (United States)

    Shimamura, Yuko; Aoki, Natsumi; Sugiyama, Yuka; Tanaka, Takashi; Murata, Masatsune; Masuda, Shuichi

    2016-01-01

    This study was performed to investigate the inhibitory effects of 16 different plant-derived polyphenols on the toxicity of staphylococcal enterotoxin A (SEA). Plant-derived polyphenols were incubated with the cultured Staphylococcus aureus C-29 to investigate the effects of these samples on SEA produced from C-29 using Western blot analysis. Twelve polyphenols (0.1-0.5 mg/mL) inhibited the interaction between the anti-SEA antibody and SEA. We examined whether the polyphenols could directly interact with SEA after incubation of these test samples with SEA. As a result, 8 polyphenols (0.25 mg/mL) significantly decreased SEA protein levels. In addition, the polyphenols that interacted with SEA inactivated the toxin activity of splenocyte proliferation induced by SEA. Polyphenols that exerted inhibitory effects on SEA toxic activity had a tendency to interact with SEA. In particular, polyphenol compounds with 1 or 2 hexahydroxydiphenoyl groups and/or a galloyl group, such as eugeniin, castalagin, punicalagin, pedunculagin, corilagin and geraniin, strongly interacted with SEA and inhibited toxin activity at a low concentration. These polyphenols may be used to prevent S. aureus infection and staphylococcal food poisoning.

  14. Plant-Derived Polyphenols Interact with Staphylococcal Enterotoxin A and Inhibit Toxin Activity.

    Directory of Open Access Journals (Sweden)

    Yuko Shimamura

    Full Text Available This study was performed to investigate the inhibitory effects of 16 different plant-derived polyphenols on the toxicity of staphylococcal enterotoxin A (SEA. Plant-derived polyphenols were incubated with the cultured Staphylococcus aureus C-29 to investigate the effects of these samples on SEA produced from C-29 using Western blot analysis. Twelve polyphenols (0.1-0.5 mg/mL inhibited the interaction between the anti-SEA antibody and SEA. We examined whether the polyphenols could directly interact with SEA after incubation of these test samples with SEA. As a result, 8 polyphenols (0.25 mg/mL significantly decreased SEA protein levels. In addition, the polyphenols that interacted with SEA inactivated the toxin activity of splenocyte proliferation induced by SEA. Polyphenols that exerted inhibitory effects on SEA toxic activity had a tendency to interact with SEA. In particular, polyphenol compounds with 1 or 2 hexahydroxydiphenoyl groups and/or a galloyl group, such as eugeniin, castalagin, punicalagin, pedunculagin, corilagin and geraniin, strongly interacted with SEA and inhibited toxin activity at a low concentration. These polyphenols may be used to prevent S. aureus infection and staphylococcal food poisoning.

  15. Concerted action of sphingomyelinase and non-hemolytic enterotoxin in pathogenic Bacillus cereus.

    Directory of Open Access Journals (Sweden)

    Viktoria M Doll

    Full Text Available Bacillus cereus causes food poisoning and serious non-gastrointestinal-tract infections. Non-hemolytic enterotoxin (Nhe, which is present in most B. cereus strains, is considered to be one of the main virulence factors. However, a B. cereus ΔnheBC mutant strain lacking Nhe is still cytotoxic to intestinal epithelial cells. In a screen for additional cytotoxic factors using an in vitro model for polarized colon epithelial cells we identified B. cereus sphingomyelinase (SMase as a strong inducer of epithelial cell death. Using single and double deletion mutants of sph, the gene encoding for SMase, and nheBC in B. cereus we demonstrated that SMase is an important factor for B. cereus cytotoxicity in vitro and pathogenicity in vivo. SMase substantially complemented Nhe induced cytotoxicity in vitro. In addition, SMase but not Nhe contributed significantly to the mortality rate of larvae in vivo in the insect model Galleria mellonella. Our study suggests that the role of B. cereus SMase as a secreted virulence factor for in vivo pathogenesis has been underestimated and that Nhe and SMase complement each other significantly to cause full B. cereus virulence hence disease formation.

  16. Inhibition of biological activity of staphylococcal enterotoxin A (SEA) by apple juice and apple polyphenols.

    Science.gov (United States)

    Rasooly, Reuven; Do, Paula M; Friedman, Mendel

    2010-05-12

    The foodborne pathogen Staphylococcus aureus produces the virulent staphylococcal enterotoxin A (SEA), a single-chain protein that consists of 233 amino acid residues with a molecular weight of 27 078 Da. SEA is a superantigen that is reported to contribute to animal (mastitis) and human (emesis, diarrhea, atopic dermatitis, arthritis, and toxic shock) syndromes. Changes of the native structural integrity may inactivate the toxin by preventing molecular interaction with cell membrane receptor sites of their host cells. In the present study, we evaluated the ability of one commercial and two freshly prepared apple juices and a commercial apple polyphenol preparation (Apple Poly) to inhibit the biological activity of SEA. Dilutions of freshly prepared apple juices and Apple Poly inhibited the biological activity of SEA without any significant cytotoxic effect on the spleen cells. Additional studies with antibody-coated immunomagnetic beads bearing specific antibodies against the toxin revealed that SEA added to apple juice appears to be largely irreversibly bound to the juice constituents. The results suggest that food-compatible and safe anti-toxin phenolic compounds can be used to inactivate SEA in vitro and possibly also in vivo, even after induction of T-cell proliferation by long-term exposure to SEA. The significance of the results for microbial food safety and human health is discussed.

  17. Evaluation of Handheld Assays for the Detection of Ricin and Staphylococcal Enterotoxin B in Disinfected Waters

    Directory of Open Access Journals (Sweden)

    Mary Margaret Wade

    2011-01-01

    Full Text Available Development of a rapid field test is needed capable of determining if field supplies of water are safe to drink by the warfighter during a military operation. The present study sought to assess the effectiveness of handheld assays (HHAs in detecting ricin and Staphylococcal Enterotoxin B (SEB in water. Performance of HHAs was evaluated in formulated tap water with and without chlorine, reverse osmosis water (RO with chlorine, and RO with bromine. Each matrix was prepared, spiked with ricin or SEB at multiple concentrations, and then loaded onto HHAs. HHAs were allowed to develop and then read visually. Limits of detection (LOD were determined for all HHAs in each water type. Both ricin and SEB were detected by HHAs in formulated tap water at or below the suggested health effect levels of 455 ng/mL and 4.55 ng/mL, respectively. However, in brominated or chlorinated waters, LODs for SEB increased to approximately 2,500 ng/mL. LODs for ricin increased in chlorinated water, but still remained below the suggested health effect level. In brominated water, the LOD for ricin increased to approximately 2,500 ng/mL. In conclusion, the HHAs tested were less effective at detecting ricin and SEB in disinfected water, as currently configured.

  18. Selection of staphylococcal enterotoxin B (SEB)-binding peptide using phage display technology

    International Nuclear Information System (INIS)

    Soykut, Esra Acar; Dudak, Fahriye Ceyda; Boyaci, Ismail Hakki

    2008-01-01

    In this study, peptides were selected to recognize staphylococcal enterotoxin B (SEB) which cause food intoxication and can be used as a biological war agent. By using commercial M13 phage library, single plaque isolation of 38 phages was done and binding affinities were investigated with phage-ELISA. The specificities of the selected phage clones showing high affinity to SEB were checked by using different protein molecules which can be found in food samples. Furthermore, the affinities of three selected phage clones were determined by using surface plasmon resonance (SPR) sensors. Sequence analysis was realized for three peptides showing high binding affinity to SEB and WWRPLTPESPPA, MNLHDYHRLFWY, and QHPQINQTLYRM amino acid sequences were obtained. The peptide sequence with highest affinity to SEB was synthesized with solid phase peptide synthesis technique and thermodynamic constants of the peptide-SEB interaction were determined by using isothermal titration calorimetry (ITC) and compared with those of antibody-SEB interaction. The binding constant of the peptide was determined as 4.2 ± 0.7 x 10 5 M -1 which indicates a strong binding close to that of antibody

  19. Evaluation of Potential Effects of NaCl and Sorbic Acid on Staphylococcal Enterotoxin A Formation

    Directory of Open Access Journals (Sweden)

    Nikoleta Zeaki

    2015-09-01

    Full Text Available The prophage-encoded staphylococcal enterotoxin A (SEA is recognized as the main cause of staphylococcal food poisoning (SFP, a common foodborne intoxication disease, caused by Staphylococcus aureus. Studies on the production of SEA suggest that activation of the SOS response and subsequent prophage induction affect the regulation of the sea gene and the SEA produced, increasing the risk for SFP. The present study aims to evaluate the effect of NaCl and sorbic acid, in concentrations relevant to food production, on SOS response activation, prophage induction and SEA production. The impact of stress was initially evaluated on steady state cells for a homogenous cell response. NaCl 2% was found to activate the SOS response, i.e., recA expression, and trigger prophage induction, in a similar way as the phage-inducer mitomycin C. In contrast, sorbic acid decreased the pH of the culture to a level where prophage induction was probably suppressed, even when combined with NaCl stress. The impact of previous physiological state of the bacteria was also addressed on cells pre-exposed to NaCl, and was found to potentially affect cell response upon exposure to further stress. The results obtained highlight the possible SFP-related risks arising from the use of preservatives during food processing.

  20. Inhibition of the superantigenic activities of Staphylococcal enterotoxin A by an aptamer antagonist.

    Science.gov (United States)

    Wang, Kaiyu; Wu, Dong; Chen, Zhuang; Zhang, Xianhui; Yang, Xiangyue; Yang, Chaoyong James; Lan, Xiaopeng

    2016-09-01

    Staphylococcal enterotoxin A (SEA) is an important component of Staphylococcus aureus pathogenesis. SEA induces T lymphocytes activation and proliferation, resulting in the release of a large number of inflammatory cytokines. Blocking the toxic cascade triggered by SEA may be an effective strategy for the treatment of SEA-induced diseases. Through a systematic evolution of ligands by exponential enrichment process, we obtained an aptamer (S3) that could bind SEA with both high affinity and specificity, with a Kd value 36.93 ± 7.29 nM (n = 3). This aptamer antagonist effectively inhibited SEA-mediated human peripheral blood mononuclear cells proliferation and inflammatory cytokines (IFN-γ, TNF-α, IL-2 and IL-6) secretion. Moreover, PEGylated S3 significantly reduced mortality in murine lethal toxic shock models established by lipopolysaccharide-potentiated SEA. Therefore, this novel aptamer antagonist has the potential to become a new strategy for treating S. aureus infections and SEA-induced diseases. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Production of vaccines for treatment of infectious diseases by transgenic plants

    Directory of Open Access Journals (Sweden)

    Kristina LEDL

    2016-04-01

    Full Text Available Since the first pathogen antigen was expressed in transgenic plants with the aim of producing edible vaccine in early 1990s, transgenic plants have become a well-established expression system for production of alternative vaccines against various human and animal infectious diseases. The main focus of plant expression systems in the last five years has been on improving expression of well-studied antigens such as porcine reproductive and respiratory syndrome (PRRSV, bovine viral diarrhea disease virus (BVDV, footh and mouth disease virus (FMDV, hepatitis B surface antigen (HBsAg, rabies G protein, rotavirus, Newcastle disease virus (NDV, Norwalk virus capsid protein (NVCP, avian influenza virus H5N1, Escherichia coli heat-labile enterotoxin subunit B (LT-B, cholera toxin B (CT-B, human immunodeficiency virus (HIV, artherosclerosis, ebola and anthrax. Significant increases in expression have been obtained using improved expression vectors, different plant species and transformation methods.

  2. ANALISIS CEMARAN BAKTERI Escherichia coli ANALISIS CEMARAN BAKTERI Escherichia coli ANALISIS CEMARAN BAKTERI Escherichia coli

    OpenAIRE

    ANGGREINI, RAHAYU

    2015-01-01

    2015 RAHAYU ANGGREINI coli Penelitian ini bertujuan untuk melakukan identifikasi cemaran bakteri E. coli O157:H7 pada daging sapi di kota Makassar. Sampel pada penelitian ini sebanyak 72 sampel Kata Kunci : Daging sapi, pasar tradisional, E. coli, E. coli O157:H7, kontaminasi bakteri, identifikasi E. coli O157:H7.

  3. A regenerable piezoelectric immunosensor on the basis of electropolymerized polypyrrole for highly selective detection of Staphylococcal Enterotoxin A in foodstuffs

    International Nuclear Information System (INIS)

    Karaseva, Nadezhda; Ermolaeva, Tatyana

    2015-01-01

    Piezoelectric immunosensors have been developed for the determination of trace concentrations of Staphylococcal enterotoxin A (SEA) in foodstuff. Antibodies against SEA were covalently immobilized on an electropolymerized polypyrrole substrate on a gold electrode which warrants increased stability of the biolayer and sensitive detection. The calibration plot is linear in the 1–80 ng∙mL -1 SEA concentration range, the limit of detection is 0.4 ng∙mL -1 , and the time of analysis is <30 min. The sensor was successfully applied to quantify SEA in chicken meat and milk. (author)

  4. Nitrate salts suppress sporulation and production of enterotoxin in Clostridium perfringens strain NCTC8239.

    Science.gov (United States)

    Yasugi, Mayo; Otsuka, Keisuke; Miyake, Masami

    2016-10-01

    Clostridium perfringens type A is a common source of food-borne illness in humans. Ingested vegetative cells sporulate in the small intestinal tract and in the process produce C. perfringens enterotoxin (CPE). Although sporulation plays a critical role in the pathogenesis of food-borne illness, the molecules triggering/inhibiting sporulation are still largely unknown. It has previously been reported by our group that sporulation is induced in C. perfringens strain NCTC8239 co-cultured with Caco-2 cells in Dulbecco's Modified Eagle Medium (DMEM). In contrast, an equivalent amount of spores was not observed when bacteria were co-cultured in Roswell Park Memorial Institute-1640 medium (RPMI). In the present study it was found that, when these two media are mixed, RPMI inhibits sporulation and CPE production induced in DMEM. When a component of RPMI was added to DMEM, it was found that calcium nitrate (Ca[NO 3 ] 2 ) significantly inhibits sporulation and CPE production. The number of spores increased when Ca(NO 3 ) 2 -deficient RPMI was used. The other nitrate salts significantly suppressed sporulation, whereas the calcium salts used did not. qPCR revealed that nitrate salts increased expression of bacterial nitrate/nitrite reductase. Furthermore, it was found that nitrite and nitric oxide suppress sporulation. In the sporulation stages, Ca(NO 3 ) 2 down-regulated the genes controlled by Spo0A, a master regulator of sporulation, but not spo0A itself. Collectively, these results indicate that nitrate salts suppress sporulation and CPE production by down-regulating Spo0A-regulated genes in C. perfringens strain NCTC8239. Nitrate reduction may be associated with inhibition of sporulation. © 2016 The Societies and John Wiley & Sons Australia, Ltd.

  5. Modeling the effects of a Staphylococcal Enterotoxin B (SEB on the apoptosis pathway

    Directory of Open Access Journals (Sweden)

    Hammamieh Rasha

    2006-05-01

    Full Text Available Abstract Background The lack of detailed understanding of the mechanism of action of many biowarfare agents poses an immediate challenge to biodefense efforts. Many potential bioweapons have been shown to affect the cellular pathways controlling apoptosis 1234. For example, pathogen-produced exotoxins such as Staphylococcal Enterotoxin B (SEB and Anthrax Lethal Factor (LF have been shown to disrupt the Fas-mediated apoptotic pathway 24. To evaluate how these agents affect these pathways it is first necessary to understand the dynamics of a normally functioning apoptosis network. This can then serve as a baseline against which a pathogen perturbed system can be compared. Such comparisons can expose both the proteins most susceptible to alteration by the agent as well as the most critical reaction rates to better instill control on a biological network. Results We explore this through the modeling and simulation of the Fas-mediated apoptotic pathway under normal and SEB influenced conditions. We stimulated human Jurkat cells with an anti-Fas antibody in the presence and absence of SEB and determined the relative levels of seven proteins involved in the core pathway at five time points following exposure. These levels were used to impute relative rate constants and build a quantitative model consisting of a series of ordinary differential equations (ODEs that simulate the network under both normal and pathogen-influenced conditions. Experimental results show that cells exposed to SEB exhibit an increase in the rate of executioner caspase expression (and subsequently apoptosis of 1 hour 43 minutes (± 14 minutes, as compared to cells undergoing normal cell death. Conclusion Our model accurately reflects these results and reveals intervention points that can be altered to restore SEB-influenced system dynamics back to levels within the range of normal conditions.

  6. Effect of different ionizing radiation dose rates on the Staphylococcal enterotoxin in mechanically deboned chicken meat

    International Nuclear Information System (INIS)

    Azevedo, Heliana de; Brito, Poliana de Paula; Fukuma, Henrique Takuji; Roque, Claudio Vitor; Custodio, Wilson; Kodama, Yasko; Miya, Norma Terugo Nago; Pereira, Jose Luiz

    2009-01-01

    Samples weighing 50g each were prepared from allotments of back with skin MDCM, to the EEB contamination or not (control). Each sample of MDCM contaminated or not with EEB was conditioned in low density polyethylene bag, frozen (-18 ± 1 deg C) for one night in a tunnel and irradiated with gamma rays from 60 Co source in this state with doses of 0.0 kGy (control), 1.5 kGy (5.7 kGy.h -1 - higher dose rate, 1.8 kGy.h -1 - intermediary dose rate and 0.6 kGy.h -1 - lower dose rate) and 3.0 kGy (8.4 kGy.h - '1 - higher dose rate, 2.4 kGy.h -1 - intermediary dose rate and 0.6 kGy.h -1 - lower dose rate). Irradiated or non irradiated MDCM samples were processed to the EEB extraction, according to the VIDAS Staph enterotoxin II kit (bioMerieux) manufacturer protocol. The calculation to determinate the MDCM EEB recovery after the sample (control or irradiated) processing were carried out applying the principle of mass balance, along the whole process. Described experiment was performed in triplicate. Results showed that the irradiation process was effective to remove the MDCM EEB, to both 1.5 kGy and 3.0 kGy. According to the expected, doses of 3.0 kGy showed the highest values of MDCM EEB removal. Regarding the effect of dose rate of radiation on the removal of EEB of the MDCM, it could be observed only for samples irradiated with 1.5 kGy radiation dose; in these processing conditions, the highest value of EEB removal was obtained for samples processed with low radiation dose rate. (author)

  7. Novel Tissue Level Effects of the Staphylococcus aureus Enterotoxin Gene Cluster Are Essential for Infective Endocarditis.

    Science.gov (United States)

    Stach, Christopher S; Vu, Bao G; Merriman, Joseph A; Herrera, Alfa; Cahill, Michael P; Schlievert, Patrick M; Salgado-Pabón, Wilmara

    2016-01-01

    Superantigens are indispensable virulence factors for Staphylococcus aureus in disease causation. Superantigens stimulate massive immune cell activation, leading to toxic shock syndrome (TSS) and contributing to other illnesses. However, superantigens differ in their capacities to induce body-wide effects. For many, their production, at least as tested in vitro, is not high enough to reach the circulation, or the proteins are not efficient in crossing epithelial and endothelial barriers, thus remaining within tissues or localized on mucosal surfaces where they exert only local effects. In this study, we address the role of TSS toxin-1 (TSST-1) and most importantly the enterotoxin gene cluster (egc) in infective endocarditis and sepsis, gaining insights into the body-wide versus local effects of superantigens. We examined S. aureus TSST-1 gene (tstH) and egc deletion strains in the rabbit model of infective endocarditis and sepsis. Importantly, we also assessed the ability of commercial human intravenous immunoglobulin (IVIG) plus vancomycin to alter the course of infective endocarditis and sepsis. TSST-1 contributed to infective endocarditis vegetations and lethal sepsis, while superantigens of the egc, a cluster with uncharacterized functions in S. aureus infections, promoted vegetation formation in infective endocarditis. IVIG plus vancomycin prevented lethality and stroke development in infective endocarditis and sepsis. Our studies support the local tissue effects of egc superantigens for establishment and progression of infective endocarditis providing evidence for their role in life-threatening illnesses. In contrast, TSST-1 contributes to both infective endocarditis and lethal sepsis. IVIG may be a useful adjunct therapy for infective endocarditis and sepsis.

  8. Rhinosinusitis derived Staphylococcal enterotoxin B possibly associates with pathogenesis of ulcerative colitis

    Directory of Open Access Journals (Sweden)

    An Zi-Yuan

    2005-09-01

    Full Text Available Abstract Background During clinical practice, we noticed that some patients with both ulcerative colitis (UC and chronic rhinosinusitis (CRS showed amelioration of UC after treatment of CRS. This study was designed to identify a possible association between CRS and UC. Methods Thirty-two patients with both CRS and UC received treatment with functional endoscopic sinus surgery (FESS for CRS. Clinical symptom scores for CRS and UC, as well as serum levels of anti-Staphylococcal enterotoxin B (SEB were evaluated at week 0 and week 12. Sinus wash fluid SEB content was measured with enzyme-linked immunosorbent assay (ELISA. The surgically removed tissues were cultured to identify growth of Staphylococcus. aureus (S. aureus. Immunohistochemistry was employed to identify anti-SEB positive cells in the colonic mucosa. Colonic biopsies were obtained and incubated with SEB. Mast cell activation in the colonic mucosa in response to incubation with SEB was observed with electron microscopy and immunoassay. Results The clinical symptom scores of CRS and UC severe scores (UCSS were significantly reduced in the UC-CRS patients after FESS. The number of cultured S. aureus colonies from the surgically removed sinus mucosa significantly correlated with the decrease in UCSS. High levels of SEB were detected in the sinus wash fluids of the patients with UC-CRS. Histamine and tryptase release was significantly higher in the culture supernate in the patients with UC-CRS than the patients with UC-only and normal controls. Anti-SEB positive cells were located in the colonic mucosa. Conclusion The pathogenesis of UC in some patients may be associated with their pre-existing CRS by a mechanism of swallowing sinusitis-derived SEB. We speculate that SEB initiates inappropriate immune reactions and inflammation in the colonic mucosa that further progresses to UC.

  9. Peracetic Acid: A Practical Agent for Sterilizing Heat-Labile Polymeric Tissue-Engineering Scaffolds

    Science.gov (United States)

    Yoganarasimha, Suyog; Trahan, William R.; Best, Al M.; Bowlin, Gary L.; Kitten, Todd O.; Moon, Peter C.

    2014-01-01

    Advanced biomaterials and sophisticated processing technologies aim at fabricating tissue-engineering scaffolds that can predictably interact within a biological environment at the cellular level. Sterilization of such scaffolds is at the core of patient safety and is an important regulatory issue that needs to be addressed before clinical translation. In addition, it is crucial that meticulously engineered micro- and nano- structures are preserved after sterilization. Conventional sterilization methods involving heat, steam, and radiation are not compatible with engineered polymeric systems because of scaffold degradation and loss of architecture. Using electrospun scaffolds made from polycaprolactone, a low melting polymer, and employing spores of Bacillus atrophaeus as biological indicators, we compared ethylene oxide, autoclaving and 80% ethanol to a known chemical sterilant, peracetic acid (PAA), for their ability to sterilize as well as their effects on scaffold properties. PAA diluted in 20% ethanol to 1000 ppm or above sterilized electrospun scaffolds in 15 min at room temperature while maintaining nano-architecture and mechanical properties. Scaffolds treated with PAA at 5000 ppm were rendered hydrophilic, with contact angles reduced to 0°. Therefore, PAA can provide economical, rapid, and effective sterilization of heat-sensitive polymeric electrospun scaffolds that are used in tissue engineering. PMID:24341350

  10. Inhibition of Cronobacter sakazakii by heat labile bacteriocins produced by probiotic LAB isolated from healthy infants.

    Science.gov (United States)

    Awaisheh, Saddam S; Al-Nabulsi, Anas A; Osaili, Tareq M; Ibrahim, Salam; Holley, Richard

    2013-09-01

    Cronobacter sakazakii is an opportunistic pathogen that can cause bacteremia, meningitis, and necrotizing enterocolitis, most often in neonates with case-fatality rates that may reach 80%. The antimicrobial activity of lactic acid bacteria against a wide range of foodborne pathogens is well-established in different types of food products. The objective of the current study was to investigate the antibacterial activity of Lactobacillus acidophilus and L. casei isolated from feces of healthy infants against different strains of C. sakazakii in agar and a rehydrated infant milk formula (RIMF) model. The inhibition zones of C. sakazakii around L. acidophilus or L. casei ranged from 22 to 32 mm on eMan Rogosa Sharpe (MRS) agar under aerobic conditions, while a slight reduction in antibacterial activity was noted on modified MRS (0.2% glucose) under anaerobic conditions. It was observed that pH-neutralized cell-free supernatant (CFS) of L. acidophilus or L. casei was inhibitory against tested C. sakazakii strains. The inhibition zones of neutralized CFS were lower than the antibacterial activities of live cultures. The antibacterial activity of CFS was abolished when CFS from L. acidophilus or L. casei was heated at 60 or 80 °C for either 10 min or 2 h, or treated with trypsin or pepsin. This was considered strong evidence that the inhibition was due to the production of bacteriocins by L. casei and L. acidophilus. Both the CFS and active growing cells of L. casei and L. acidophilus were able to reduce the viability of C. sakazakii in the RIMF model. The results may extend the use of natural antimicrobials instead of conventional preservation methods to improve the safety of RIMF. © 2013 Institute of Food Technologists®

  11. Detergent inhibited, heat labile nucleoside triphosphatase in cores of avian myeloblastosis virus

    DEFF Research Database (Denmark)

    Jensen, Kaj Frank

    1978-01-01

    Endogenous DNA synthesis was studied in isolated core particles of avian myeloblastosis virus. It was found that cores contained an enzymatic activity which rapidly converted the added nucleoside triphosphates to diphosphates (but not further) at 0 degrees C, thus inhibiting DNA synthesis...

  12. Conjugation in Escherichia coli

    Science.gov (United States)

    Boyer, Herbert

    1966-01-01

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

  13. Comparison of Genotypes and Enterotoxin Genes Between Staphylococcus aureus Isolates from Blood and Nasal Colonizers in a Korean Hospital

    Science.gov (United States)

    Peck, Kyong Ran; Baek, Jin Yang; Song, Jae-Hoon

    2009-01-01

    In this study, we investigated the genetic background of 70 Staphylococcus aureus isolates (36 methicillin-resistant S. aureus [MRSA] and 34 methicillin-susceptible S. aureus [MSSA]) obtained from blood at a Korean tertiary-care hospital, using spa typing, multilocus sequence typing, and SCCmec typing. In addition, the prevalence of enterotoxin (sea, seb, sec, sed, see, seg, seh, sei, and sek), tst, and pvl genes among the samples was assessed via polymerase chain reaction, and the results were compared with those of 95 isolates of S. aureus obtained from nasal swabs. All MRSA isolates from blood, except one, belonged to three major clones: sequence type (ST)5-MRSA-II, ST72-MRSA-II (or IVA), and ST239-MRSA-III, among which ST5-MRSA-II was the predominant clone. The prevalence of enterotoxin genes in the S. aureus isolates obtained from blood differed significantly from those from the nasal swabs for the sea, seb, sec, and seh gene. In particular, the seb and sec genes were detected exclusively in the MRSA isolates of ST5 or spa-CC002, thereby suggesting the co-adaptation of virulence genes with the genetic background and their contribution to biological fitness. PMID:19654937

  14. Sensitive chemiluminescence immunoassay for staphylococcal enterotoxin C1 based on the use of dye-encapsulated mesoporous silica nanoparticles

    International Nuclear Information System (INIS)

    Tao, Liang; Zhang, Chunmei; Sun, Yuanjie; Jin, Boquan; Yang, Kun; Li, Xiaohua; Zhang, Zhujun; Zhang, Jinpeng; Yan, Kuocheng

    2016-01-01

    A chemiluminescent immunoassay for the staphylococcal enterotoxin C1 (SEC1) based on the use of dye-encapsulated mesoporous silica nanoparticles (m-SiNPs) as a label is described. The dyes are retained in the m-SiNPs via strong hydrophobic interactions. The assay comprises the following steps: (a) Microplates coated with antibody against SEC1 are filled with sample upon which the SEC antigen will be bound to the surface; (b) following a washing step, secondary antibody linked to m-SiNPs (that were covalently labeled with rhodamine 6G and fluorescein) were added to form the sandwich complex; (c) after another washing step, bis(2,4,6-trichlorophenyl) oxalate, H_2O_2 and imidazole are added to generate chemiluminescence whose intensity is proportional to the number of m-SiNPs and thus to the number of antigen (SEC) molecules. It is found that the use of functionalized m-SiNPs strongly amplifies the signal. Enterotoxin SEC1 can be detected by this method in the 0.025 to 2 ng⋅mL"-"1 concentration range, the detection limit is 19 pg⋅mL"-"1 (at 3σ), and the relative standard deviation (for 11 parallel measurements at a 1 ng⋅mL"-"1 level) is 4.6 %. The use of an automated chemiluminescence analyzer further improves detection. (author)

  15. Magnetic Bead and Fluorescent Silica Nanoparticles Based Optical Immunodetection of Staphylococcal Enterotoxin B (SEB in Bottled Water

    Directory of Open Access Journals (Sweden)

    Shiva K. RASTOGI

    2009-10-01

    Full Text Available Staphylococcal enterotoxins (SEs are a major cause of food-borne diseases, most commonly SEs assayed immunologically with ELISA. An immunoassay based on fluorescein dye doped silica dioxide nanoparticles (F-SiNPs and magnetic bead (MB is described here for the detection of staphylococcal enterotoxin B (SEB. F-SiNPs have unique optical properties which make them attractive for biosensing. The water-in-oil (W/O reverse microemulsion method was used for the synthesis of F-SiNPs (~ 95 nm of diameter. The F-SiNPs were characterized using SEM, TEM and FTIR spectroscopy. The detection of SEB is preformed in PBS buffer, and bottled drinking water using sandwich immunoassay format. Target analytes were captured using MBs modified with the antigen-specific “capture” antibody, and detected using F-SiNP labeled secondary antigen-specific antibody. We report a limit of detection down to 1 ng/mL SEB spiked sample in less than 2 hr assay time using fluorocount method. This study demonstrates the bio warfare agent SEB capture by magnetic beads and detection using F-SiNPs.

  16. A Chimeric protein of CFA/I, CS6 subunits and LTB/STa toxoid protects immunized mice against enterotoxigenic Escherichia coli.

    Science.gov (United States)

    Zeinalzadeh, Narges; Salmanian, Ali Hatef; Goujani, Goli; Amani, Jafar; Ahangari, Ghasem; Akhavian, Asal; Jafari, Mahyat

    2017-07-01

    Enterotoxigenic Escherichia Coli (ETEC) strains are the commonest bacteria causing diarrhea in children in developing countries and travelers to these areas. Colonization factors (CFs) and enterotoxins are the main virulence determinants in ETEC pathogenesis. Heterogeneity of CFs is commonly considered the bottleneck to developing an effective vaccine. It is believed that broad spectrum protection against ETEC would be achieved by induced anti-CF and anti-enterotoxin immunity simultaneously. Here, a fusion antigen strategy was used to construct a quadrivalent recombinant protein called 3CL and composed of CfaB, a structural subunit of CFA/I, and CS6 structural subunits, LTB and STa toxoid of ETEC. Its anti-CF and antitoxin immunogenicity was then assessed. To achieve high-level expression, the 3CL gene was synthesized using E. coli codon bias. Female BALB/C mice were immunized with purified recombinant 3CL. Immunized mice developed antibodies that were capable of detecting each recombinant subunit in addition to native CS6 protein and also protected the mice against ETEC challenge. Moreover, sera from immunized mice also neutralized STa toxin in a suckling mouse assay. These results indicate that 3CL can induce anti-CF and neutralizing antitoxin antibodies along with introducing CFA/I as a platform for epitope insertion. © 2017 The Societies and John Wiley & Sons Australia, Ltd.

  17. Presence of Classical Enterotoxin Genes, agr Typing, Antimicrobial Resistance, and Genetic Diversity of Staphylococcus aureus from Milk of Cows with Mastitis in Southern Brazil.

    Science.gov (United States)

    Kroning, Isabela S; Iglesias, Mariana A; Mendonça, Karla S; Lopes, Graciela V; Silva, Wladimir P

    2018-05-01

    Staphylococcus aureus is a common causative agent of bovine mastitis in dairy cows and commonly associated with foodborne disease outbreaks. The aim of this study was to evaluate the presence of enterotoxin genes, agr typing, antimicrobial resistance, and genetic diversity of S. aureus isolated from milk of cows with mastitis in dairy farms from southern Brazil. Results showed that 7 (22.6%) of 31 S. aureus isolates were positive for enterotoxin genes. Specifically, the genes encoding for enterotoxins A ( n = 4), C ( n = 2), and B ( n = 1) were detected. Isolates belonging to the agr group III (10 of 31, 32.2%) and agr group I (7 of 31, 22.5%) were the most common. To our knowledge, this is the first report of both agr I and III in the same S. aureus isolate from milk of cows with bovine mastitis. The antimicrobial resistance test showed that 54% of the isolates were multiresistant to antimicrobial agents. The macrorestriction analysis produced 16 different major SmaI pulsed-field gel electrophoresis patterns, with up to two subpatterns. Moreover, the presence of some S. aureus clones in a distinct area was observed. Although this study characterized a limited number of S. aureus isolates, the presence of classical enterotoxin genes and resistance to multiple antimicrobial agents reinforces the importance of this microorganism to animal and human health. In addition, similar genetic profiles have been identified in distinct geographic areas, suggesting clonal dissemination of S. aureus in dairy herds from southern Brazil.

  18. Detection of coding genes for enterotoxins in Bacillus cereus by PCR and their products by BCET-RPLA and ELISA Assay

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    Marcela Vyletělová

    2010-01-01

    Full Text Available Determination of enterotoxin production, diarrhoeal and emetic gene identification was studied in 41 Bacillus cereus strains isolated from raw cows’ and raw goats’ milk, pasteurized milk, dairy products during technological processing and from dairy plant equipment. Presence of enterotoxins was detected by BCET-RPLA (HBL and ELISA immunoassay (NHE. Gene identification (nheA, nheB, nheC, hblA, hblC, hblD, bceT, cytK-1, cytK-2, entFM and ces was achieved by means of PCR. Enterotoxin HBL was detected in 32 strains, enterotoxin NHE in all 41 strains. Presence of all three genes nheA, nheB and nheC was confirmed in 40 strains and genes hblA, hblC and hblD in 29 strains. Comparison of used methods was as follow: 1 BCET-RPLA (which detects L2 component and PCR (positive or negative all three hblA, hblC and hblD gene detection were identical in 30 (73%; 2 ELISA (NheA and PCR (all three nheC, nheB and nheA gene expression were identical in 40 (98% cases isolated strains.

  19. Comparison of toxicity neutralization-, ELISA- and PCR tests for typing of Clostridium perfringens and detection of the enterotoxin gene by PCR

    DEFF Research Database (Denmark)

    Møller, Kristian; Ahrens, Peter

    1996-01-01

    A polymerase chain reaction (PCR) was developed for the specific amplification of a part of each of the five Clostridium perfringens toxin genes: alpha (alpha), beta (beta), epsilon (epsilon), iota (iota), and enterotoxin (CPE). While the toxicity neutralization test (TNT) only showed limited...

  20. Enterotoxin Producing Ability And Antimicrobial Susceptibility Of Coagulase-Negative Staphylococci Isolated From Goat Milk Cheese And Salted Yoghurt In Turkey

    Directory of Open Access Journals (Sweden)

    S. Pehlivanlar Onen

    2017-10-01

    Full Text Available The aim of this study was to determine enterotoxin producing ability and antimicrobial susceptibility of coagulase negative staphylococci CNS in goats bulk milk cheese and salted yoghurt. CNS strains were identified by using GP card in VITEK 2 system. The presence of enterotoxins was determined by enzyme immunoassay test by using RIDASCREEN test kit. Antibiotic susceptibility in CNS strains was detected by using AST-P640 card in VITEK 2 system. A total of 100 CNS strains were isolated in 22 55 bulk milk samples and in 23 57.5 cheese samples. Staphylococcus spp. could not be isolated from salted yoghurt samples. The most encountered species were S. caprae 51.9 S. chromogenes 11.5 and S. xylosus 9.6 from milk samples and S. saprophyticus 60.4 S. xylosus 12.5 and S. haemolyticus 8.3 from cheese samples. Four CNS strains 4 isolated from samples were capable of producing enterotoxin. While all isolates were resistant to at least one antibiotic 74 of CNS strains showed resistance to two or more antibiotics. Enterotoxin production ability and high antibiotic resistance of the CNS strains isolated from goat bulk milk and cheese can lead to a risk for public health.

  1. Noncontiguous Finished Genome Sequence of Staphylococcus aureus KLT6, a Staphylococcal Enterotoxin B-Positive Strain Involved in a Food Poisoning Outbreak in Switzerland

    Science.gov (United States)

    Tobes, Raquel; Manrique, Marina; Brozynska, Marta; Stephan, Roger; Pareja, Eduardo

    2013-01-01

    We present the first complete genome sequence of a Staphylococcus aureus strain assigned to clonal complex 12. The strain was isolated in a food poisoning outbreak due to contaminated potato salad in Switzerland in 2009, and it produces staphylococcal enterotoxin B. PMID:23704175

  2. Growth and enterotoxin production of Staphylococcus aureus during the manufacture and ripening of Camembert-type cheeses from raw goats' milk.

    Science.gov (United States)

    Meyrand, A; Boutrand-Loei, S; Ray-Gueniot, S; Mazuy, C; Gaspard, C E; Jaubert, G; Perrin, G; Lapeyre, C; Vernozy-Rozand, C

    1998-09-01

    Tests were carried out to determine the effect of manufacturing procedures for a Camembert-type cheese from raw goats' milk on the growth and survival of Staphylococcus aureus organisms added to milk at the start of the process, and to study the possible presence of staphylococcal enterotoxin A in these cheeses. The initial staphylococcal counts were, respectively, 2, 3, 4, 5 and 6 log cfu ml-1. Cheese was prepared following the industrial specifications and ripened for 41 d. Detection of enterotoxins was done by the Vidas SET test and by an indirect double-sandwich ELISA technique using antienterotoxin monoclonal antibodies. Generally, numbers of microbes increased at a similar rate during manufacture in all cheeses until salting. During the ripening period, the aerobic plate count population and Staph. aureus levels remained stable and high. There was an approximately 1 log reduction of Staph. aureus in cheeses made with an initial inoculum of Staph. aureus greater than 10(3) cfu ml-1 at the end of the ripening period (41 d) compared with the count at 22 h. The level of staphylococcal enterotoxin A recovered varied from 1 to 3.2 ng g-1 of cheese made with an initial population of 10(3)-10(6) cfu ml-1. No trace of enterotoxin A was detected in cheeses made with the lowest Staph. aureus inoculum used in this study.

  3. Detection of enterotoxins produced by B. cereus through PCR analysis of ground and roasted coffee samples in Rio de Janeiro, Brazil

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    Cyllene de Matos Ornelas da Cunha Corrêa de Souza

    2011-06-01

    Full Text Available Coffee is one of the most appreciated drinks in the world. Coffee ground is obtained from the fruit of a small plant that belongs to the genus Coffea. Coffea arabica and Coffea canephora robusta are the two most commercially important species. They are more commonly known as arabica and robusta, respectively. Two-thirds of Coffea arabica plants are grown in South and Central America, and Eastern Africa - the place of origin for this coffee species. Contamination by microorganisms has been a major matter affecting coffee quality in Brazil, mainly due to the harvesting method adopted. Brazilian harvests are based on fruits collected from the ground mixed with those that fall on collection cloths. As the Bacillus cereus bacterium frequently uses the soil as its environmental reservoir, it is easily capable of becoming a contaminant. This study aimed to evaluate the contamination and potential of B. cereus enterotoxin genes encoding the HBL and NHE complexes, which were observed in strains of ground and roasted coffee samples sold in Rio de Janeiro. The PCR (Polymerase Chain Reaction results revealed high potential of enterotoxin production in the samples. The method described by Speck (1984 was used for the isolation of contaminants. The investigation of the potential production of enterotoxins through isolates of the microorganism was performed using the B. cereus enterotoxin Reverse Passive Latex Agglutination test-kit (BCET-RPLA, Oxoid, according to the manufacturer's instructions. The potential of enterotoxin production was investigated using polymerase chain reaction (PCR methods for hblA, hblD and hblC genes (encoding hemolysin HBL and for nheA, nheB and nheC genes (encoding non-hemolytic enterotoxin - NHE. Of all the 17 strains, 100% were positive for at least 1 enterotoxin gene; 52.9% (9/17 were positive for the 3 genes encoding the HBL complex; 35.3% (6/17 were positive for the three NHE encoding genes; and 29.4% (5/17 were positive for

  4. Acetic acid increases the phage-encoded enterotoxin A expression in Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    da Silva Ayla

    2010-05-01

    Full Text Available Abstract Background The effects of acetic acid, a common food preservative, on the bacteriophage-encoded enterotoxin A (SEA expression and production in Staphylococcus aureus was investigated in pH-controlled batch cultures carried out at pH 7.0, 6.5, 6.0, 5.5, 5.0, and 4.5. Also, genomic analysis of S. aureus strains carrying sea was performed to map differences within the gene and in the temperate phage carrying sea. Results The sea expression profile was similar from pH 7.0 to 5.5, with the relative expression peaking in the transition between exponential and stationary growth phase and falling during stationary phase. The levels of sea mRNA were below the detection limit at pH 5.0 and 4.5, confirmed by very low SEA levels at these pH values. The level of relative sea expression at pH 6.0 and 5.5 were nine and four times higher, respectively, in the transitional phase than in the exponential growth phase, compared to pH 7.0 and pH 6.5, where only a slight increase in relative expression in the transitional phase was observed. Furthermore, the increase in sea expression levels at pH 6.0 and 5.5 were observed to be linked to increased intracellular sea gene copy numbers and extracellular sea-containing phage copy numbers. The extracellular SEA levels increased over time, with highest levels produced at pH 6.0 in the four growth phases investigated. Using mitomycin C, it was verified that SEA was at least partially produced as a consequence of prophage induction of the sea-phage in the three S. aureus strains tested. Finally, genetic analysis of six S. aureus strains carrying the sea gene showed specific sea phage-groups and two versions of the sea gene that may explain the different sea expression and production levels observed in this study. Conclusions Our findings suggest that the increased sea expression in S. aureus caused by acetic acid induced the sea-encoding prophage, linking SEA production to the lifecycle of the phage.

  5. Staphylococcal enterotoxin-specific IgE antibodies in atopic dermatitis.

    Science.gov (United States)

    Ide, Fumihito; Matsubara, Tomoyo; Kaneko, Miho; Ichiyama, Takashi; Mukouyama, Tokuko; Furukawa, Susumu

    2004-06-01

    The authors clarified the clinical significance of the measurement of serum concentrations of specific IgE antibodies to staphylococcal enterotoxin (SE) A- and SEB in atopic dermatitis (AD). The serum concentrations of SEA- and SEB-specific IgE antibodies in 140 pediatric patients with AD were measured with an immuno CAP -radioallergosorbent test system (RAST). To check the cross-reaction of specific IgE antibodies to SEA/SEB and other allergens, the CAP RAST fluorescent enzyme immunoassay inhibition test was performed. Forty-seven patients (33.6%) tested positive for either SEA- or SEB-specific IgE antibodies. School children showed higher positive rates of SEA/SEB-specific IgE antibodies than infants or young children. The patients with severe AD and those with exacerbation of symptoms in summer, had higher positive rates of SEA/SEB-specific IgE antibodies than patients with mild AD or those with exacerbation in winter. In addition, the positive rates of specific IgE antibodies to both dog-dander and cat-dander were higher in patients with positive SEA/SEB-specific IgE antibodies than in patients with negative ones. No cross-reactions occurred among specific IgE antibodies to SEA/SEB and dog/cat dander with one patient's serum, which had positive IgE-specific antibodies against cat/dog dander and SEA/SEB. The positive rate of SEA/SEB-specific IgE antibodies in the patients with dogs and/or cats as pets was 48.4%, which was higher than in those with no pets. Atopic dermatitis patients who exhibit high positive rates of SEA/SEB-specific IgE antibodies were found to be school children, severe cases, cases with high serum concentrations of total IgE, cases with exacerbation in summer, and cases with dogs and/or cats as pets. The measurement of serum concentrations of specific IgE antibodies to SEA and SEB, thus has some value for evaluating AD patients.

  6. Staphylococcal enterotoxin A regulates bone marrow granulocyte trafficking during pulmonary inflammatory disease in mice

    Energy Technology Data Exchange (ETDEWEB)

    Takeshita, W.M.; Gushiken, V.O.; Ferreira-Duarte, A.P.; Pinheiro-Torres, A.S.; Roncalho-Buck, I.A. [Department of Biology and Physiology, Faculty of Medicine of Jundiai (FMJ), Jundiai, SP (Brazil); Squebola-Cola, D.M.; Mello, G.C.; Anhê, G.F.; Antunes, E. [Department of Pharmacology, Faculty of Medical Sciences, University of Campinas (UNICAMP), Campinas, SP (Brazil); DeSouza, I.A., E-mail: ivanidesouza@uol.com.br [Department of Biology and Physiology, Faculty of Medicine of Jundiai (FMJ), Jundiai, SP (Brazil)

    2015-09-15

    Pulmonary neutrophil infiltration produced by Staphylococcal enterotoxin A (SEA) airway exposure is accompanied by marked granulocyte accumulation in bone marrow (BM). Therefore, the aim of this study was to investigate the mechanisms of BM cell accumulation, and trafficking to circulating blood and lung tissue after SEA airway exposure. Male BALB/C mice were intranasally exposed to SEA (1 μg), and at 4, 12 and 24 h thereafter, BM, circulating blood, bronchoalveolar lavage (BAL) fluid and lung tissue were collected. Adhesion of BM granulocytes and flow cytometry for MAC-1, LFA1-α and VLA-4 and cytokine and/or chemokine levels were assayed after SEA-airway exposure. Prior exposure to SEA promoted a marked PMN influx to BAL and lung tissue, which was accompanied by increased counts of immature and/or mature neutrophils and eosinophils in BM, along with blood neutrophilia. Airway exposure to SEA enhanced BM neutrophil MAC-1 expression, and adhesion to VCAM-1 and/or ICAM-1-coated plates. Elevated levels of GM-CSF, G-CSF, INF-γ, TNF-α, KC/CXCL-1 and SDF-1α were detected in BM after SEA exposure. SEA exposure increased production of eosinopoietic cytokines (eotaxin and IL-5) and BM eosinophil VLA-4 expression, but it failed to affect eosinophil adhesion to VCAM-1 and ICAM-1. In conclusion, BM neutrophil accumulation after SEA exposure takes place by integrated action of cytokines and/or chemokines, enhancing the adhesive responses of BM neutrophils and its trafficking to lung tissues, leading to acute lung injury. BM eosinophil accumulation in SEA-induced acute lung injury may occur via increased eosinopoietic cytokines and VLA-4 expression. - Highlights: • Airway exposure to SEA causes acute lung inflammation. • SEA induces accumulation of bone marrow (BM) in immature and mature neutrophils. • SEA increases BM granulocyte or BM PMN adhesion to ICAM-1 and VCAM-1, and MAC-1 expression. • SEA induces BM elevations of CXCL-1, INF-γ, TNF-α, GM-CSF, G-CSF and

  7. Staphylococcal enterotoxin A regulates bone marrow granulocyte trafficking during pulmonary inflammatory disease in mice

    International Nuclear Information System (INIS)

    Takeshita, W.M.; Gushiken, V.O.; Ferreira-Duarte, A.P.; Pinheiro-Torres, A.S.; Roncalho-Buck, I.A.; Squebola-Cola, D.M.; Mello, G.C.; Anhê, G.F.; Antunes, E.; DeSouza, I.A.

    2015-01-01

    Pulmonary neutrophil infiltration produced by Staphylococcal enterotoxin A (SEA) airway exposure is accompanied by marked granulocyte accumulation in bone marrow (BM). Therefore, the aim of this study was to investigate the mechanisms of BM cell accumulation, and trafficking to circulating blood and lung tissue after SEA airway exposure. Male BALB/C mice were intranasally exposed to SEA (1 μg), and at 4, 12 and 24 h thereafter, BM, circulating blood, bronchoalveolar lavage (BAL) fluid and lung tissue were collected. Adhesion of BM granulocytes and flow cytometry for MAC-1, LFA1-α and VLA-4 and cytokine and/or chemokine levels were assayed after SEA-airway exposure. Prior exposure to SEA promoted a marked PMN influx to BAL and lung tissue, which was accompanied by increased counts of immature and/or mature neutrophils and eosinophils in BM, along with blood neutrophilia. Airway exposure to SEA enhanced BM neutrophil MAC-1 expression, and adhesion to VCAM-1 and/or ICAM-1-coated plates. Elevated levels of GM-CSF, G-CSF, INF-γ, TNF-α, KC/CXCL-1 and SDF-1α were detected in BM after SEA exposure. SEA exposure increased production of eosinopoietic cytokines (eotaxin and IL-5) and BM eosinophil VLA-4 expression, but it failed to affect eosinophil adhesion to VCAM-1 and ICAM-1. In conclusion, BM neutrophil accumulation after SEA exposure takes place by integrated action of cytokines and/or chemokines, enhancing the adhesive responses of BM neutrophils and its trafficking to lung tissues, leading to acute lung injury. BM eosinophil accumulation in SEA-induced acute lung injury may occur via increased eosinopoietic cytokines and VLA-4 expression. - Highlights: • Airway exposure to SEA causes acute lung inflammation. • SEA induces accumulation of bone marrow (BM) in immature and mature neutrophils. • SEA increases BM granulocyte or BM PMN adhesion to ICAM-1 and VCAM-1, and MAC-1 expression. • SEA induces BM elevations of CXCL-1, INF-γ, TNF-α, GM-CSF, G-CSF and

  8. Detection of Ampicillin Resistance Genes (bla in Clinical Isolates of Escherichia coli with Polymerase Chain Reaction Method

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    Tiana Milanda

    2014-09-01

    Full Text Available Escherichia coli is a rod negative Gram which could be pathogenic, if its value increases or located in outer gastrointestinal tract. Pathogenic E. coli will produce enterotoxin which will cause diarrhoea or infection in urine tract. Ampicilin was one of particular antibiotics to overcome infection. Ampicilin nowadays is no longer used as primary medicine, because of its resistance case. The aim of this research is to detect the presence of gene which is responsible to ampicilin resistant E. coli. We used isolated midstream urine from cystitis object in Hasan Sadikin Hospital (RSHS as samples. Polymerase Chain Reaction (PCR method (colony-PCR and DNA-PCR were done to invenstigate the antibiotic resistency. Based on the result of antibiotic susceptibility testing to ampicillin, E. coli samples were resistant to ampicilin. Elektroforegram products of colony-PCR and DNA-PCR showed that the resistance case of ampicilin caused by bla gene (199 bp. Selective and rational antibiotic treatment is required to prevent ampicillin resistance in patients with symptoms

  9. Enterohemorrhagic Escherichia coli (EHEC

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    Abdullah Kilic

    2011-08-01

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

  10. Can E. coli fly?

    DEFF Research Database (Denmark)

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

    2018-01-01

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

  11. Endogenous E. coli endophthalmitis.

    Science.gov (United States)

    Shammas, H F

    1977-01-01

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

  12. Vaccines for preventing enterotoxigenic Escherichia coli (ETEC) diarrhoea.

    Science.gov (United States)

    Ahmed, Tanvir; Bhuiyan, Taufiqur R; Zaman, K; Sinclair, David; Qadri, Firdausi

    2013-07-05

    Infection with enterotoxigenic Escherichia coli (ETEC) bacteria is a common cause of diarrhoea in adults and children in developing countries and is a major cause of 'travellers' diarrhoea' in people visiting or returning from endemic regions. A killed whole cell vaccine (Dukoral®), primarily designed and licensed to prevent cholera, has been recommended by some groups to prevent travellers' diarrhoea in people visiting endemic regions. This vaccine contains a recombinant B subunit of the cholera toxin that is antigenically similar to the heat labile toxin of ETEC. This review aims to evaluate the clinical efficacy of this vaccine and other vaccines designed specifically to protect people against diarrhoea caused by ETEC infection. To evaluate the efficacy, safety, and immunogenicity of vaccines for preventing ETEC diarrhoea. We searched the Cochrane Infectious Disease Group Specialized Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, LILACS, and http://clinicaltrials.gov up to December 2012. Randomized controlled trials (RCTs) and quasi-RCTs comparing use of vaccines to prevent ETEC with use of no intervention, a control vaccine (either an inert vaccine or a vaccine normally given to prevent an unrelated infection), an alternative ETEC vaccine, or a different dose or schedule of the same ETEC vaccine in healthy adults and children living in endemic regions, intending to travel to endemic regions, or volunteering to receive an artificial challenge of ETEC bacteria. Two authors independently assessed each trial for eligibility and risk of bias. Two independent reviewers extracted data from the included studies and analyzed the data using Review Manager (RevMan) software. We reported outcomes as risk ratios (RR) with 95% confidence intervals (CI). We assessed the quality of the evidence using the GRADE approach. Twenty-four RCTs, including 53,247 participants, met the inclusion criteria. Four studies assessed the protective

  13. Structure of Staphylococcal Enterotoxin E in Complex with TCR Defines the Role of TCR Loop Positioning in Superantigen Recognition.

    Directory of Open Access Journals (Sweden)

    Karin E J Rödström

    Full Text Available T cells are crucial players in cell-mediated immunity. The specificity of their receptor, the T cell receptor (TCR, is central for the immune system to distinguish foreign from host antigens. Superantigens are bacterial toxins capable of inducing a toxic immune response by cross-linking the TCR and the major histocompatibility complex (MHC class II and circumventing the antigen specificity. Here, we present the structure of staphylococcal enterotoxin E (SEE in complex with a human T cell receptor, as well as the unligated T cell receptor structure. There are clear structural changes in the TCR loops upon superantigen binding. In particular, the HV4 loop moves to circumvent steric clashes upon complex formation. In addition, a predicted ternary model of SEE in complex with both TCR and MHC class II displays intermolecular contacts between the TCR α-chain and the MHC, suggesting that the TCR α-chain is of importance for complex formation.

  14. Staphylococcus aureus and staphylococcal enterotoxin A in breaded chicken products: detection and behavior during the cooking process.

    Science.gov (United States)

    Pepe, Olimpia; Blaiotta, Giuseppe; Bucci, Francesca; Anastasio, Marilena; Aponte, Maria; Villani, Francesco

    2006-11-01

    In this study we examined the presence of Staphylococcus aureus and staphylococcal enterotoxin A (SEA) in 20 industrial breaded chicken products obtained from different retail butchers and supermarket stores in Italy. The levels of contamination in the products analyzed were quite low, although the pH values and water activities (a(w)) in the samples considered were in ranges favorable for S. aureus growth. As demonstrated by phenotypic and molecular characterization, in spite of the high percentage of coagulase-positive Staphylococcus strains, only three strains could be referred to the species S. aureus. Moreover, all the strains were negative in PCR assays targeting staphylococcal enterotoxin genes (seA to seE, seG to seJ, and seM to seO), as well as the toxic shock syndrome toxin 1 gene, and no SEA was detected in the retail breaded chicken samples analyzed by a reversed passive latex agglutination assay or by Western blotting. Hence, we evaluated the thermal resistance of two strains of SEA-producing S. aureus in a laboratory-scale preparation of precooked breaded chicken cutlets. The heat treatment employed in the manufacture determined the inactivation of S. aureus cells, but the preformed SEA remained active during product storage at 4 degrees C. The presence of the staphylococci and, in particular, of S. aureus in the retail breaded chicken products analyzed is a potential health risk for consumers since the pH and a(w) values of these kinds of products are favorable for S. aureus growth. The thermal process used during their manufacture can limit staphylococcal contamination but cannot eliminate preformed toxins.

  15. Comparative Genomics and Identification of an Enterotoxin-Bearing Pathogenicity Island, SEPI-1/SECI-1, in Staphylococcus epidermidis Pathogenic Strains.

    Science.gov (United States)

    Argemi, Xavier; Nanoukon, Chimène; Affolabi, Dissou; Keller, Daniel; Hansmann, Yves; Riegel, Philippe; Baba-Moussa, Lamine; Prévost, Gilles

    2018-02-25

    Staphylococcus epidermidis is a leading cause of nosocomial infections, majorly resistant to beta-lactam antibiotics, and may transfer several mobile genetic elements among the members of its own species, as well as to Staphylococcus aureus ; however, a genetic exchange from S. aureus to S. epidermidis remains controversial. We recently identified two pathogenic clinical strains of S. epidermidis that produce a staphylococcal enterotoxin C3-like (SEC) similar to that by S. aureus pathogenicity islands. This study aimed to determine the genetic environment of the SEC-coding sequence and to identify the mobile genetic elements. Whole-genome sequencing and annotation of the S. epidermidis strains were performed using Illumina technology and a bioinformatics pipeline for assembly, which provided evidence that the SEC-coding sequences were located in a composite pathogenicity island that was previously described in the S. epidermidis strain FRI909, called SePI-1/SeCI-1, with 83.8-89.7% nucleotide similarity. Various other plasmids were identified, particularly p_3_95 and p_4_95, which carry antibiotic resistance genes ( hsrA and dfrG , respectively), and share homologies with SAP085A and pUSA04-2-SUR11, two plasmids described in S. aureus . Eventually, one complete prophage was identified, ΦSE90, sharing 30 out of 52 coding sequences with the Acinetobacter phage vB_AbaM_IME200. Thus, the SePI-1/SeCI-1 pathogenicity island was identified in two pathogenic strains of S. epidermidis that produced a SEC enterotoxin causing septic shock. These findings suggest the existence of in vivo genetic exchange from S. aureus to S. epidermidis .

  16. Comparative Genomics and Identification of an Enterotoxin-Bearing Pathogenicity Island, SEPI-1/SECI-1, in Staphylococcus epidermidis Pathogenic Strains

    Directory of Open Access Journals (Sweden)

    Xavier Argemi

    2018-02-01

    Full Text Available Staphylococcus epidermidis is a leading cause of nosocomial infections, majorly resistant to beta-lactam antibiotics, and may transfer several mobile genetic elements among the members of its own species, as well as to Staphylococcus aureus; however, a genetic exchange from S. aureus to S. epidermidis remains controversial. We recently identified two pathogenic clinical strains of S. epidermidis that produce a staphylococcal enterotoxin C3-like (SEC similar to that by S. aureus pathogenicity islands. This study aimed to determine the genetic environment of the SEC-coding sequence and to identify the mobile genetic elements. Whole-genome sequencing and annotation of the S. epidermidis strains were performed using Illumina technology and a bioinformatics pipeline for assembly, which provided evidence that the SEC-coding sequences were located in a composite pathogenicity island that was previously described in the S. epidermidis strain FRI909, called SePI-1/SeCI-1, with 83.8–89.7% nucleotide similarity. Various other plasmids were identified, particularly p_3_95 and p_4_95, which carry antibiotic resistance genes (hsrA and dfrG, respectively, and share homologies with SAP085A and pUSA04-2-SUR11, two plasmids described in S. aureus. Eventually, one complete prophage was identified, ΦSE90, sharing 30 out of 52 coding sequences with the Acinetobacter phage vB_AbaM_IME200. Thus, the SePI-1/SeCI-1 pathogenicity island was identified in two pathogenic strains of S. epidermidis that produced a SEC enterotoxin causing septic shock. These findings suggest the existence of in vivo genetic exchange from S. aureus to S. epidermidis.

  17. Subinhibitory concentrations of thymol reduce enterotoxins A and B and alpha-hemolysin production in Staphylococcus aureus isolates.

    Directory of Open Access Journals (Sweden)

    Jiazhang Qiu

    Full Text Available BACKGROUND: Targeting bacterial virulence factors is now gaining interest as an alternative strategy to develop new types of anti-infective agents. It has been shown that thymol, when used at low concentrations, can inhibit the TSST-1 secretion in Staphylococcus aureus. However, there are no data on the effect of thymol on the production of other exotoxins (e.g., alpha-hemolysin and enterotoxins by S. aureus. METHODOLOGY/PRINCIPAL FINDINGS: Secretion of alpha-hemolysin, SEA and SEB in both methicillin-sensitive and methicillin-resistant S. aureus isolates cultured with graded subinhibitory concentrations of thymol was detected by immunoblot analysis. Hemolysin and tumor necrosis factor (TNF release assays were performed to elucidate the biological relevance of changes in alpha-hemolysin, SEA and SEB secretion induced by thymol. In addition, the influence of thymol on the transcription of hla, sea, and seb (the genes encoding alpha-hemolysin, SEA and SEB, respectively was analyzed by quantitative RT-PCR. Thymol inhibited transcription of hla, sea and seb in S. aureus, resulting in a reduction of alpha-hemolysin, SEA and SEB secretion and, thus, a reduction in hemolytic and TNF-inducing activities. CONCLUSIONS/SIGNIFICANCE: Subinhibitory concentrations of thymol decreased the production of alpha-hemolysin, SEA and SEB in both MSSA and MRSA in a dose-dependent manner. These data suggest that thymol may be useful for the treatment of S. aureus infections when used in combination with beta-lactams and glycopeptide antibiotics, which induce expression of alpha-hemolysin and enterotoxins at subinhibitory concentrations. Furthermore, the structure of thymol may potentially be used as a basic structure for development of drugs aimed against these bacterial virulence factors.

  18. Thioredoxin from Escherichia coli

    International Nuclear Information System (INIS)

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

    1978-01-01

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

  19. Resistance Pattern and Molecular Characterization of Enterotoxigenic Escherichia coli (ETEC Strains Isolated in Bangladesh.

    Directory of Open Access Journals (Sweden)

    Yasmin A Begum

    Full Text Available Enterotoxigenic Escherichia coli (ETEC is a common cause of bacterial infection leading to acute watery diarrhea in infants and young children as well as in travellers to ETEC endemic countries. Ciprofloxacin is a broad-spectrum antimicrobial agent nowadays used for the treatment of diarrhea. This study aimed to characterize ciprofloxacin resistant ETEC strains isolated from diarrheal patients in Bangladesh.A total of 8580 stool specimens from diarrheal patients attending the icddr,b Dhaka hospital was screened for ETEC between 2005 and 2009. PCR and Ganglioside GM1- Enzyme Linked Immuno sorbent Assay (ELISA was used for detection of Heat labile (LT and Heat stable (ST toxins of ETEC. Antimicrobial susceptibilities for commonly used antibiotics and the minimum inhibitory concentration (MIC of nalidixic acid, ciprofloxacin and azithromycin were examined. DNA sequencing of representative ciprofloxacin resistant strains was performed to analyze mutations of the quinolone resistance-determining region of gyrA, gyrB, parC and parE. PCR was used for the detection of qnr, a plasmid mediated ciprofloxacin resistance gene. Clonal variations among ciprofloxacin resistant (CipR and ciprofloxacin susceptible (CipS strains were determined by Pulsed-field gel electrophoresis (PFGE.Among 1067 (12% ETEC isolates identified, 42% produced LT/ST, 28% ST and 30% LT alone. Forty nine percent (n = 523 of the ETEC strains expressed one or more of the 13 tested colonization factors (CFs as determined by dot blot immunoassay. Antibiotic resistance of the ETEC strains was observed as follows: ampicillin 66%, azithromycin 27%, ciprofloxacin 27%, ceftriazone 13%, cotrimaxazole 46%, doxycycline 44%, erythromycin 96%, nalidixic acid 83%, norfloxacin 27%, streptomycin 48% and tetracycline 42%. Resistance to ciprofloxacin increased from 13% in 2005 to 34% in 2009. None of the strains was resistant to mecillinam. The MIC of the nalidixic acid and ciprofloxacin of representative

  20. escherichia coli serotypes confirmed in experimental mammary ...

    African Journals Online (AJOL)

    DJFLEX

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

  1. Antibiotic resistant Escherichia coli in southeastern Australian pig herds and implications for surveillance.

    Science.gov (United States)

    van Breda, L K; Dhungyel, O P; Ward, M P

    2018-02-01

    To investigate public health implications of antibiotics to control post-weaning scours, we surveyed 22 commercial pig herds in southeastern Australia. Fifty faecal samples per herd were collected from pre- and post-weaned piglets. Presumptive Escherichia coli isolates were confirmed by MALDI-TOF MS. Isolates (n = 325) were screened for susceptibility to 19 veterinary antibiotics using MIC broth microdilution. All 325 E. coli isolates underwent further testing against 27 antibiotics used in human medicine and were screened for ETEC adhesin and enterotoxin genes (F4 (K88), F5 (K99), F6 (987P), F18, F41, STa, STb, Stx2e and LT) by multiplex PCR. Isolates identified as phenotypically resistant to third-generation cephalosporin (3GC) and aminoglycoside antibiotics were screened by multiplex PCR/reverse line blot to detect common β-lactam and aminoglycosides resistance genes, confirmed by sequencing. Twenty (6.1%) of the E. coli isolates were resistant to 3GC antibiotics and 24 (7.4%) to the aminoglycoside antibiotic gentamicin. Genetic analysis revealed six different extended spectrum β-lactamase (ESBL) genes (blaCTX-M-1, -14, -15, -27, blaSHV-12 and blaCMY-2-like genes), four of which have not been previously reported in Australian pigs. Critically, the prevalence of 3GC resistance was higher in non-pathogenic (non-ETEC) isolates and those from clinically normal (non-diarrhoeal) samples. This highlights the importance of non-ETECE. coli as reservoirs of antimicrobial resistance genes in piglet pens. Antimicrobial resistance surveillance in pig production focused on diagnostic specimens from clinically-affected animals might be potentially misleading. We recommend that surveillance for emerging antimicrobial resistance such as to 3GC antibiotics should include clinically healthy pigs. © 2017 Blackwell Verlag GmbH.

  2. Coupling immunomagnetic separation on magnetic beads with matrix-assisted laser desorption ionization-time of flight mass spectrometry for detection of Staphylococcal Enterotoxin B

    Czech Academy of Sciences Publication Activity Database

    Schlosser, G.; Kačer, P.; Kuzma, Marek; Szilágyi, Z.; Sorrentino, Z.; Manzo, C.; Pizzano, R.; Malorni, L.; Poscfalvi, G.

    2007-01-01

    Roč. 73, č. 21 (2007), s. 6945-6952 ISSN 0099-2240 Grant - others:IT(IT) project SIFORTI (MIUR-CNR, Legge 449/97); XE(XE) 94.05.09.103, ARINCO 94.IT.16.028 Institutional research plan: CEZ:AV0Z50200510 Keywords : mass spectrometry * staphylococcal enterotoxin b * bacterial protein toxins Subject RIV: EE - Microbiology, Virology Impact factor: 4.004, year: 2007

  3. Prevalence of enterotoxin-encoding genes and antimicrobial resistance in coagulase-negative and coagulase-positive Staphylococcus isolates from black pudding

    Directory of Open Access Journals (Sweden)

    Tiane Martin de Moura

    2012-10-01

    Full Text Available INTRODUCTION: Staphylococcal species are pathogens that are responsible for outbreaks of foodborne diseases. The aim of this study was to investigate the prevalence of enterotoxin-genes and the antimicrobial resistance profile in staphylococcus coagulase-negative (CoNS and coagulasepositive (CoPS isolates from black pudding in southern Brazil. METHODS: Two hundred typical and atypical colonies from Baird-Parker agar were inoculated on mannitol salt agar. Eighty-two mannitol-positive staphylococci were submitted to conventional biochemical tests and antimicrobial susceptibility profiling. The presence of coagulase (coa and enterotoxin (se genes was investigated by polymerase chain reaction. RESULTS: The isolates were divided into 2 groups: 75.6% (62/82 were CoNS and 24.4% (20/82 were CoPS. The biochemical tests identified 9 species, of which Staphylococcus saprophyticus (37.8% and Staphylococcus carnosus (15.9% were the most prevalent. Antimicrobial susceptibility tests showed resistance phenotypes to antibiotics widely administered in humans, such as gentamicin, tetracycline, chloramphenicol, and erythromycin. The coa gene was detected in 19.5% (16/82 of the strains and 4 polymorphic DNA fragments were observed. Five CoNS isolates carrying the coa gene were submitted for 16S rRNA sequencing and 3 showed similarity with CoNS. Forty strains were positive for at least 1 enterotoxin-encoding gene, the genes most frequently detected were sea (28.6% and seb (27.5%. CONCLUSIONS: The presence of antimicrobial resistant and enterotoxin-encoding genes in staphylococci isolates from black pudding indicated that this fermented food may represent a potential health risk, since staphylococci present in food could cause foodborne diseases or be a possible route for the transfer of antimicrobial resistance to humans.

  4. Hybrids of Shigatoxigenic and Enterotoxigenic Escherichia coli (STEC/ETEC) Among Human and Animal Isolates in Finland.

    Science.gov (United States)

    Nyholm, O; Heinikainen, S; Pelkonen, S; Hallanvuo, S; Haukka, K; Siitonen, A

    2015-11-01

    Diarrhoeagenic Escherichia coli (DEC) cause serious foodborne infections in humans. Total of 450 Shigatoxigenic E. coli (STEC) strains isolated from humans, animals and environment in Finland were examined by multiplex PCR targeting the virulence genes of various DEC pathogroups simultaneously. One per cent (3/291) of the human STEC and 14% (22/159) of the animal and environmental STEC had genes typically present in enterotoxigenic E. coli (ETEC). The strains possessed genes encoding both Shiga toxin 1 and/or 2 (stx1 and/or stx2 ) and ETEC-specific heat-stable (ST) enterotoxin Ia (estIa). The identified stx subtypes were stx1a, stx1c, stx2a, stx2d and stx2g. The three human STEC/ETEC strains were isolated from the patients with haemolytic uraemic syndrome and diarrhoea and from an asymptomatic carrier. The animal STEC/ETEC strains were isolated from cattle and moose. The human and animal STEC/ETEC strains belonged to 11 serotypes, of which O2:H27, O15:H16, O101:H-, O128:H8 and O141:H8 have previously been described to be associated with human disease. Identification of multiple virulence genes offers further information for assessing the virulence potential of STEC and other DEC. The emergence of novel hybrid pathogens should be taken into account in the patient care and epidemiological surveillance. © 2015 Blackwell Verlag GmbH.

  5. Influence of holding temperature on the growth and survival of Salmonella spp. and Staphylococcus aureus and the production of staphylococcal enterotoxin in egg products.

    Science.gov (United States)

    Yang, S E; Yu, R C; Chou, C C

    2001-01-22

    In this study, growth and survival of Salmonella spp. and Staphylococcus aureus in steamed egg and scrambled egg held at 5, 18, 22, 37, 55 and 60 degrees C are investigated. The production of staphylococcal enterotoxin in steamed egg is also examined. Results reveal that Salmonella spp. and Staph. aureus in the egg products multiply best at 37 degrees C, followed closely by 22 and 18 degrees C. Neither pathogen showed growth in the egg products held at 5 degrees C. Initial inoculation dose, holding temperature and holding time affected the population of both organisms found in the egg products. Staphylococcal enterotoxin A (SEA) and B (SEB) are detected only in the egg products held at 37 or 22 degrees C. After holding at 37 degrees C for 36 h, scrambled egg inoculated with ca. 5.0 log cfu/g Staph. aureus contains the highest levels of SEA (> 64 ng/g) and SEB (> 64 ng/g). Although Salmonella spp. and Staph. aureus grow better in steamed eggs than in scrambled eggs, production of staphylococcal enterotoxin, in general, was higher in scrambled eggs than in steamed eggs. On the other hand, a repaid destruction of the test organisms in steamed eggs held at 60 degrees C was observed. Holding the steamed eggs at 60 degrees C, Salmonella spp. and Staph. aureus with an initial population of ca. 5.9 and 5.6 log cfu/g, respectively, reduced to a non-detectable level in 1 h.

  6. Prevalence and Genetic Characteristics of Staphylococcus aureus and Staphylococcus argenteus Isolates Harboring Panton-Valentine Leukocidin, Enterotoxins, and TSST-1 Genes from Food Handlers in Myanmar.

    Science.gov (United States)

    Aung, Meiji Soe; San, Thida; Aye, Mya Mya; Mya, San; Maw, Win Win; Zan, Khin Nyein; Htut, Wut Hmone Win; Kawaguchiya, Mitsuyo; Urushibara, Noriko; Kobayashi, Nobumichi

    2017-08-04

    Asymptomatic carriers of toxigenic Staphylococcus aureus are potential source of diseases, including food poisoning. Toxigenic potential and genetic traits of colonizing S. aureus were investigated for 563 healthy food handlers in Myanmar. Carriage of S. aureus was found in 110 individuals (19.5%), and a total of 144 S. aureus isolates were recovered from nasal cavities (110 isolates) and hands (34 isolates). Panton-Valentine leucocidin genes ( pvl ) were detected in 18 isolates (12.5%), among which 11 isolates were classified into coa -VIa, agr type III, and ST1930 (CC96) that had been also detected in pvl -positive clinical isolates in Myanmar. A pvl -positive, ST2250 nasal isolate was identified as S. argenteus , a novel coagulase-positive staphylococcus species. Toxic shock syndrome toxin-1 (TSST-1) gene was detected in five pvl -negative isolates. All of the 144 isolates harbored at least one of the 21 enterotoxin(-like) gene(s). The most prevalent enterotoxin(-like) gene was selw (98%), followed by selx (97%), sei (28%), sely (28%), sem (26%), sel (24%), and sea and sec (22% each). Considerable genetic diversity with five groups was detected for selw . The present study revealed the relatively high rate of pvl , as well as the wide distribution of enterotoxin(-like) genes among colonizing S. aureus in Myanmar.

  7. Development and preclinical evaluation of safety and immunogenicity of an oral ETEC vaccine containing inactivated E. coli bacteria overexpressing colonization factors CFA/I, CS3, CS5 and CS6 combined with a hybrid LT/CT B subunit antigen, administered alone and together with dmLT adjuvant.

    Science.gov (United States)

    Holmgren, J; Bourgeois, L; Carlin, N; Clements, J; Gustafsson, B; Lundgren, A; Nygren, E; Tobias, J; Walker, R; Svennerholm, A-M

    2013-05-07

    A first-generation oral inactivated whole-cell enterotoxigenic Escherichia coli (ETEC) vaccine, comprising formalin-killed ETEC bacteria expressing different colonization factor (CF) antigens combined with cholera toxin B subunit (CTB), when tested in phase III studies did not significantly reduce overall (generally mild) ETEC diarrhea in travelers or children although it reduced more severe ETEC diarrhea in travelers by almost 80%. We have now developed a novel more immunogenic ETEC vaccine based on recombinant non-toxigenic E. coli strains engineered to express increased amounts of CF antigens, including CS6 as well as an ETEC-based B subunit protein (LCTBA), and the optional combination with a nontoxic double-mutant heat-labile toxin (LT) molecule (dmLT) as an adjuvant. Two test vaccines were prepared under GMP: (1) A prototype E. coli CFA/I-only formalin-killed whole-cell+LCTBA vaccine, and (2) A "complete" inactivated multivalent ETEC-CF (CFA/I, CS3, CS5 and CS6 antigens) whole-cell+LCTBA vaccine. These vaccines, when given intragastrically alone or together with dmLT in mice, were well tolerated and induced strong intestinal-mucosal IgA antibody responses as well as serum IgG and IgA responses to each of the vaccine CF antigens as well as to LT B subunit (LTB). Both mucosal and serum responses were further enhanced (adjuvanted) when the vaccines were co-administered with dmLT. We conclude that the new multivalent oral ETEC vaccine, both alone and especially in combination with the dmLT adjuvant, shows great promise for further testing in humans. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. Control of Virulence Gene Expression by the Master Regulator, CfaD, in the Prototypical Enterotoxigenic Escherichia coli Strain, H10407

    Directory of Open Access Journals (Sweden)

    Carla Hodson

    2017-08-01

    Full Text Available Enterotoxigenic Escherichia coli (ETEC is the most common bacterial cause of diarrhea in children in developing countries, as well as in travelers to these countries. To cause disease, ETEC needs to produce a series of virulence proteins including enterotoxins, colonization factors and secretion pathways, which enable this pathogen to colonize the human small intestine and deliver enterotoxins to epithelial cells. Previously, a number of studies have demonstrated that CfaD, an AraC-like transcriptional regulator, plays a key role in virulence gene expression by ETEC. In this study, we carried out a transcriptomic analysis of ETEC strain, H10407, grown under different conditions, and determined the complete set of genes that are regulated by CfaD. In this way, we identified a number of new target genes, including rnr-1, rnr-2, etpBAC, agn43, flu, traM and ETEC_3214, whose expression is strongly activated by CfaD. Using promoter-lacZ reporters, primer extension and electrophoretic mobility shift assays, we characterized the CfaD-mediated activation of several selected target promoters. We also showed that the gut-associated environmental signal, sodium bicarbonate, stimulates CfaD-mediated upregulation of its virulence target operons. Finally, we screened a commercial small molecule library and identified a compound (CH-1 that specifically inhibited the regulatory function of CfaD, and by 2-D analoging, we identified a second inhibitor (CH-2 with greater potency.

  9. An alternative explanation for the occurrence of short circuit current increases in the small intestine following challenge by bacterial enterotoxins.

    Science.gov (United States)

    Lucas, M L

    2013-10-01

    Secretory diarrhoeal disease due to enterotoxins is thought to arise from the enhancement to pathologically high rates of normally occurring chloride ion and therefore fluid secretion from enterocytes. In support of this concept, many enterotoxins increase intestinal short-circuit current, regarded now as faithfully reflecting the increased chloride ion secretion. Contradicting this assumption, STa reduces absorption but does not cause secretion in vivo although short-circuit current is increased in vitro. There is therefore a mismatch between an assumed enterocyte mediated secretory event that should but does not cause net fluid secretion and an undoubtedly increased short-circuit current. It is proposed here that short-circuit current increases are not themselves secretory events but result from interrupted fluid absorption. A noteworthy feature of compounds that inhibit the increase in short-circuit current is that the majority are vasoactive, neuroactive or both. In general, vasodilator substances increase current. An alternative hypothesis for the origin of short-circuit current increases is that these result from reflex induction of electrogenic fluid absorption. This reflex enhances a compensatory response that is also present at a cellular level. An intestinal reflex is therefore proposed by which decreases in interstitial and intravascular volume or pressure within the intestine initiate an electrogenic fluid absorption mechanism that compensates for the loss of electrically neutral fluid absorption. This hypothesis would explain the apparently complex pharmacology of short-circuit current increases since many depressor substances have receptors in common with enterocytes and enteric nerves. The proposed alternative view of the origin of short-circuit current increases assumes that these do not represent chloride secretion from the enterocytes. This view may therefore aid the successful development of anti-diarrhoeal drugs to overcome a major cause of

  10. The 2.3 {angstrom} crystal structure of cholera toxin B subunit pentamer: Choleragenoid

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Rong-Guang; Westbrook, M.L. [Argonne National Lab., IL (United States); Maulik, P.R.; Reed, R.A.; Shipley, G. [Boston Univ., MA (United States). School of Medicine; Westbrook, E.M. [Argonne National Lab., IL (United States)]|[Northwestern Univ., Evanston, IL (United States); Scott, D.L.; Otwinowski, Z. [Yale Univ., New Haven, CT (United States)

    1996-02-01

    Cholera toxin, a heterohexameric AB{sub 5} enterotoxin released by Vibrio cholera, induces a profuse secretory diarrhea in susceptible hosts. Choleragenoid, the B subunit pentamer of cholera toxin, directs the enzymatic A subunit to its target by binding to GM{sub 1} gangliosides exposed on the luminal surface of intestinal epithelial cells. We have solved the crystal structure of choleragenoid at 2.3 {Angstrom} resolution by combining single isomorphous replacement with non-crystallographic symmetry averaging. The structure of the B subunits, and their pentameric arrangement, closely resembles that reported for the intact holotoxin (choleragen), the heat-labile enterotoxin from E. coli, and for a choleragenoid-GM{sub 1} pentasaccharide complex. In the absence of the A subunit the central cavity of the B pentamer is a highly solvated channel. The binding of the A subunit or the receptor pentasaccharide to choleragenoid has only a modest effect on the local stereochemistry and does not perceptibly alter the subunit interface.

  11. PART I. ESCHERICHIA COLI

    Directory of Open Access Journals (Sweden)

    Sanaa Mahdi Oraibi

    2016-11-01

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

  12. Attenuation of massive cytokine response to the staphylococcal enterotoxin B superantigen by the innate immunomodulatory protein lactoferrin

    Science.gov (United States)

    Hayworth, J L; Kasper, K J; Leon-Ponte, M; Herfst, C A; Yue, D; Brintnell, W C; Mazzuca, D M; Heinrichs, D E; Cairns, E; Madrenas, J; Hoskin, D W; McCormick, J K; Haeryfar, S M M

    2009-01-01

    Staphylococcal enterotoxin B (SEB) is a pyrogenic exotoxin and a potent superantigen which causes massive T cell activation and cytokine secretion, leading to profound immunosuppression and morbidity. The inhibition of SEB-induced responses is thus considered a goal in the management of certain types of staphylococcal infections. Lactoferrin (LF) is a multi-functional glycoprotein with both bacteriostatic and bactericidal activities. In addition, LF is known to have potent immunomodulatory properties. Given the anti-microbial and anti-inflammatory properties of this protein, we hypothesized that LF can modulate T cell responses to SEB. Here, we report that bovine LF (bLF) was indeed able to attenuate SEB-induced proliferation, interleukin-2 production and CD25 expression by human leucocyte antigen (HLA)-DR4 transgenic mouse T cells. This inhibition was not due to bLF's iron-binding capacity, and could be mimicked by the bLF-derived peptide lactoferricin. Cytokine secretion by an engineered SEB-responsive human Jurkat T cell line and by peripheral blood mononuclear cells from healthy donors was also inhibited by bLF. These findings reveal a previously unrecognized property of LF in modulation of SEB-triggered immune activation and suggest a therapeutic potential for this naturally occurring protein during toxic shock syndrome. PMID:19659771

  13. Ultrasensitive electrochemical immunoassay of staphylococcal enterotoxin B in food using enzyme-nanosilica-doped carbon nanotubes for signal amplification.

    Science.gov (United States)

    Tang, Dianping; Tang, Juan; Su, Biling; Chen, Guonan

    2010-10-27

    A new sandwich-type electrochemical immunoassay for ultrasensitive detection of staphylococcal enterotoxin B (SEB) in food was developed using horseradish peroxidase-nanosilica-doped multiwalled carbon nanotubes (HRPSiCNTs) for signal amplification. Rabbit polyclonal anti-SEB antibodies immobilized on the screen-printed carbon electrode (SPCE) and covalently bound to the HRPSiCNTs were used as capture antibodies and detection antibodies, respectively. In the presence of SEB analyte, the sandwich-type immunocomplex could be formed between the immobilized anti-SEB on the SPCE and anti-SEB-labeled HRPSiCNTs, and the carried HRP could catalyze the electrochemical reduction of H2O2 with the help of thionine. The high content of HRP in the HRPSiCNTs could greatly amplify the electrochemical signal. Under optimal conditions, the reduction current increased with the increase of SEB in the sample, and exhibited a dynamic range of 0.05-15 ng/mL with a low detection limit (LOD) of 10 pg/mL SEB (at 3σ). Intra- and interassay coefficients of variation were below 10%. In addition, the assay was evaluated with SEB spiked samples including watermelon juice, soymilk, apple juice, and pork food, receiving excellent correlation with results from commercially available enzyme-linked immunosorbent assay (ELISA).

  14. Prophage-Encoded Staphylococcal Enterotoxin A: Regulation of Production in Staphylococcus aureus Strains Representing Different Sea Regions

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    Nikoleta Zeaki

    2015-12-01

    Full Text Available The present study investigates the nature of the link between the staphylococcal enterotoxin A (SEA gene and the lifecycle of Siphoviridae bacteriophages, including the origin of strain variation regarding SEA production after prophage induction. Five strains representing three different genetic lines of the sea region were studied under optimal and prophage-induced growth conditions and the Siphoviridae lifecycle was followed through the phage replicative form copies and transcripts of the lysogenic repressor, cro. The role of SOS response on prophage induction was addressed through recA transcription in a recA-disruption mutant. Prophage induction was found to increase the abundance of the phage replicative form, the sea gene copies and transcripts and enhance SEA production. Sequence analysis of the sea regions revealed that observed strain variances were related to strain capacity for prophage induction, rather than sequence differences in the sea region. The impact of SOS response activation on the phage lifecycle was demonstrated by the absence of phage replicative form copies in the recA-disruption mutant after prophage induction. From this study it emerges that all aspects of SEA-producing strain, the Siphoviridae phage and the food environment must be considered when evaluating SEA-related hazards.

  15. Immunochemical and PCR analysis of Staphylococcus aureus Enterotoxin B (SEB in milk and fruit juices collected in Lahore, Pakistan

    Directory of Open Access Journals (Sweden)

    Dar Nadia

    2013-01-01

    Full Text Available Enterotoxins secreted by S. aureus are known as a food-poisoning agent that is associated with various gastro-intestinal pathological conditions. In this study, a one-step immunodetection method was devised for routine checking of SEB in milk and fruit juices available locally. Antibodies against recombinant SEB were raised, purified, and cross reactivity was checked against clinically important bacteria (Shigella flexneri, Streptococci, Salmonella typhi, Klebsiella and Bacillus subtilis. Purified anti-SEB antibodies were conjugated with gold nanoparticles (Ab-GNPs for direct detection of SEB in samples. SEB (33%, 4.76% and 15% was found in non-sterilized milk (118, sterilized milk (42 and juices (60, respectively. Coagulase, MSA tests and PCR amplification of 725 bp of the SEB gene confirmed the presence of S. aureus in the collected samples positive for SEB. Immunoassay is easy, reliable and less time consuming and will be helpful to detect the SEB in food samples at local level.

  16. Zoonotic Potential and Antibiotic Resistance of Escherichia coli in Neonatal Calves in Uruguay.

    Science.gov (United States)

    Umpiérrez, Ana; Bado, Inés; Oliver, Martín; Acquistapace, Sofía; Etcheverría, Analía; Padola, Nora Lía; Vignoli, Rafael; Zunino, Pablo

    2017-09-27

    Escherichia coli is one of the main etiological agents of neonatal calf diarrhea (NCD). The objective of this study was to assess the presence of virulence genes, genetic diversity, and antibiotic resistance mechanisms in E. coli associated with NCD in Uruguay. PCR was used to assess the presence of intimin, Shiga-like toxin, and stable and labile enterotoxin genes. Resistance to fluoroquinolones and oxyimino-cephalosporins was estimated on Müller-Hinton agar plates. Further antibiotic disc-diffusion tests were performed to assess bacterial multi-resistance. The presence of PMQR, ESBL, MCR-1, and integron genes was evaluated. Isolates were typed using ERIC-PCR, and 20 were selected for MLST, adhesion to Hep-2 cells, in vitro biofilm formation, and eukaryotic cytotoxicity. The prevalence of ETEC genes was lower than 3% in each case (estA and elt). Six isolates were EPEC (eae+) and 2 were EHEC/STEC (eae+/stx1+). The results of a diversity analysis showed high genetic heterogenicity among isolates. Additionally, different sequence types, including ST10, ST21, and ST69, were assigned to selected isolates. Thirty-six percent (96/264) of the isolates were fluoroquinolone-resistant, with 61/96 (63.5%) being multidrug-resistant. Additionally, 6 were oxyimino-cephalosporin-resistant. The qnrB, qnrS1, and bla CTX-M-14 genes were detected, whereas no isolates carried the mcr-1 gene. Isolates had the ability to adhere to Hep-2 cells and form biofilms. Only 1 isolate expressed toxins in vitro. E. coli from NCD cases in Uruguay are very diverse, potentially virulent, and may interact with eukaryotic cells. Zoonotic potential, together with resistance traits and the presence of horizontal transfer mechanisms, may play a significant role in infections caused by these microorganisms.

  17. Clinical trial to evaluate safety and immunogenicity of an oral inactivated enterotoxigenic Escherichia coli prototype vaccine containing CFA/I overexpressing bacteria and recombinantly produced LTB/CTB hybrid protein.

    Science.gov (United States)

    Lundgren, A; Leach, S; Tobias, J; Carlin, N; Gustafsson, B; Jertborn, M; Bourgeois, L; Walker, R; Holmgren, J; Svennerholm, A-M

    2013-02-06

    We have developed a new oral vaccine against enterotoxigenic Escherichia coli (ETEC) diarrhea containing killed recombinant E. coli bacteria expressing increased levels of ETEC colonization factors (CFs) and a recombinant protein (LCTBA), i.e. a hybrid between the binding subunits of E. coli heat labile toxin (LTB) and cholera toxin (CTB). We describe a randomized, comparator controlled, double-blind phase I trial in 60 adult Swedish volunteers of a prototype of this vaccine. The safety and immunogenicity of the prototype vaccine, containing LCTBA and an E. coli strain overexpressing the colonization factor CFA/I, was compared to a previously developed oral ETEC vaccine, consisting of CTB and inactivated wild type ETEC bacteria expressing CFA/I (reference vaccine). Groups of volunteers were given two oral doses of either the prototype or the reference vaccine; the prototype vaccine was administered at the same or a fourfold higher dosage than the reference vaccine. The prototype vaccine was found to be safe and equally well-tolerated as the reference vaccine at either dosage tested. The prototype vaccine induced mucosal IgA (fecal secretory IgA and intestine-derived IgA antibody secreting cell) responses to both LTB and CFA/I, as well as serum IgA and IgG antibody responses to LTB. Immunization with LCTBA resulted in about twofold higher mucosal and systemic IgA responses against LTB than a comparable dose of CTB. The higher dose of the prototype vaccine induced significantly higher fecal and systemic IgA responses to LTB and fecal IgA responses to CFA/I than the reference vaccine. These results demonstrate that CF over-expression and inclusion of the LCTBA hybrid protein in an oral inactivated ETEC vaccine does not change the safety profile when compared to a previous generation of such a vaccine and that the prototype vaccine induces significant dose dependent mucosal immune responses against CFA/I and LTB. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Effect of different ionizing radiation doses and dose rates, using Cobalt-60 and electrons beam sources, on the staphylococcal enterotoxin inoculated in mechanically deboned chicken meat

    Energy Technology Data Exchange (ETDEWEB)

    Pomarico Neto, Walter; Brito, Poliana de Paula; Azevedo, Heliana de; Roque, Claudio Vitor; Fukuma, Henrique Takuji, E-mail: pbrito@cnen.gov.br, E-mail: hazevedo@cnen.gov.br, E-mail: cvroque@cnen.gov.br, E-mail: htfukuma@cnen.gov.br [Brazilian Nuclear Energy Commission (LAPOC/CNEN), Pocos de Caldas, MG (Brazil); Kodama, Yasko, E-mail: ykodama@ipen.br [Nuclear and Energy Research Institute (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Miya, Norma Terugo Nago; Pereira, Jose Luiz, E-mail: miya@fea.unicamp.br, E-mail: pereira@fea.unicamp.br [Campinas State University (UNICAMP), SP (Brazil). Dept. of Food Sciences

    2011-07-01

    The purpose of food irradiation is the destruction of present pathogenic microorganisms and the increase of shelf life of foods. To achieve this process, the source of cobalt-60 and the electron accelerator can be used. The mechanically deboned chicken meat (MDCM) is used for the production of traditional meat products, and it may come to present pathogenic microorganisms such as staphylococcus aureus, a bacterium that produces enterotoxin, which causes food poisoning. The objective of this study is to analyze the effect of ionizing irradiation with different doses and dose rates, deriving from different radiation sources, on staphylococcal enterotoxin type B (SEB) in the MDCM. 50 g samples of MDCM were prepared in a batch of 6 kg of MDCM. The samples were contaminated, with the exception of the control, with SEB in amounts of about 100 ng. Then they were conditioned in a transparent bag made of low density polyethylene, frozen at -18{+-}1 deg C overnight and irradiated in these conditions with doses of 0.0 kGy (control), 1.5 kGy and 3.0 kGy, and with three different dose rates, both in the Cobalt-60 and the electron accelerator. The experiments were conducted in quintuplicate. The SEB extraction from the MDCM was performed according to the protocol recommended by the manufacturer of the kit VIDAS Staph Enterotoxin II (bioMerrieux). The principle of mass balance was used to determine the actual amount of SEB removed by irradiation. The treatment that presented the best results was the one with a dose of 1.5 kGy, high dose rate of the electron accelerator. (author)

  19. Effect of different ionizing radiation doses and dose rates, using Cobalt-60 and electrons beam sources, on the staphylococcal enterotoxin inoculated in mechanically deboned chicken meat

    International Nuclear Information System (INIS)

    Pomarico Neto, Walter; Brito, Poliana de Paula; Azevedo, Heliana de; Roque, Claudio Vitor; Fukuma, Henrique Takuji; Kodama, Yasko; Miya, Norma Terugo Nago; Pereira, Jose Luiz

    2011-01-01

    The purpose of food irradiation is the destruction of present pathogenic microorganisms and the increase of shelf life of foods. To achieve this process, the source of cobalt-60 and the electron accelerator can be used. The mechanically deboned chicken meat (MDCM) is used for the production of traditional meat products, and it may come to present pathogenic microorganisms such as staphylococcus aureus, a bacterium that produces enterotoxin, which causes food poisoning. The objective of this study is to analyze the effect of ionizing irradiation with different doses and dose rates, deriving from different radiation sources, on staphylococcal enterotoxin type B (SEB) in the MDCM. 50 g samples of MDCM were prepared in a batch of 6 kg of MDCM. The samples were contaminated, with the exception of the control, with SEB in amounts of about 100 ng. Then they were conditioned in a transparent bag made of low density polyethylene, frozen at -18±1 deg C overnight and irradiated in these conditions with doses of 0.0 kGy (control), 1.5 kGy and 3.0 kGy, and with three different dose rates, both in the Cobalt-60 and the electron accelerator. The experiments were conducted in quintuplicate. The SEB extraction from the MDCM was performed according to the protocol recommended by the manufacturer of the kit VIDAS Staph Enterotoxin II (bioMerrieux). The principle of mass balance was used to determine the actual amount of SEB removed by irradiation. The treatment that presented the best results was the one with a dose of 1.5 kGy, high dose rate of the electron accelerator. (author)

  20. Multiple-Strain Approach and Probabilistic Modeling of Consumer Habits in Quantitative Microbial Risk Assessment: A Quantitative Assessment of Exposure to Staphylococcal Enterotoxin A in Raw Milk.

    Science.gov (United States)

    Crotta, Matteo; Rizzi, Rita; Varisco, Giorgio; Daminelli, Paolo; Cunico, Elena Cosciani; Luini, Mario; Graber, Hans Ulrich; Paterlini, Franco; Guitian, Javier

    2016-03-01

    Quantitative microbial risk assessment (QMRA) models are extensively applied to inform management of a broad range of food safety risks. Inevitably, QMRA modeling involves an element of simplification of the biological process of interest. Two features that are frequently simplified or disregarded are the pathogenicity of multiple strains of a single pathogen and consumer behavior at the household level. In this study, we developed a QMRA model with a multiple-strain approach and a consumer phase module (CPM) based on uncertainty distributions fitted from field data. We modeled exposure to staphylococcal enterotoxin A in raw milk in Lombardy; a specific enterotoxin production module was thus included. The model is adaptable and could be used to assess the risk related to other pathogens in raw milk as well as other staphylococcal enterotoxins. The multiplestrain approach, implemented as a multinomial process, allowed the inclusion of variability and uncertainty with regard to pathogenicity at the bacterial level. Data from 301 questionnaires submitted to raw milk consumers were used to obtain uncertainty distributions for the CPM. The distributions were modeled to be easily updatable with further data or evidence. The sources of uncertainty due to the multiple-strain approach and the CPM were identified, and their impact on the output was assessed by comparing specific scenarios to the baseline. When the distributions reflecting the uncertainty in consumer behavior were fixed to the 95th percentile, the risk of exposure increased up to 160 times. This reflects the importance of taking into consideration the diversity of consumers' habits at the household level and the impact that the lack of knowledge about variables in the CPM can have on the final QMRA estimates. The multiple-strain approach lends itself to use in other food matrices besides raw milk and allows the model to better capture the complexity of the real world and to be capable of geographical

  1. Identification of novel Clostridium perfringens type E strains that carry an iota toxin plasmid with a functional enterotoxin gene.

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    Kazuaki Miyamoto

    Full Text Available Clostridium perfringens enterotoxin (CPE is a major virulence factor for human gastrointestinal diseases, such as food poisoning and antibiotic associated diarrhea. The CPE-encoding gene (cpe can be chromosomal or plasmid-borne. Recent development of conventional PCR cpe-genotyping assays makes it possible to identify cpe location (chromosomal or plasmid in type A isolates. Initial studies for developing cpe genotyping assays indicated that all cpe-positive strains isolated from sickened patients were typable by cpe-genotypes, but surveys of C. perfringens environmental strains or strains from feces of healthy people suggested that this assay might not be useful for some cpe-carrying type A isolates. In the current study, a pulsed-field gel electrophoresis Southern blot assay showed that four cpe-genotype untypable isolates carried their cpe gene on a plasmid of ∼65 kb. Complete sequence analysis of the ∼65 kb variant cpe-carrying plasmid revealed no intact IS elements and a disrupted cytosine methyltransferase (dcm gene. More importantly, this plasmid contains a conjugative transfer region, a variant cpe gene and variant iota toxin genes. The toxin genes encoded by this plasmid are expressed based upon the results of RT-PCR assays. The ∼65 kb plasmid is closely related to the pCPF4969 cpe plasmid of type A isolates. MLST analyses indicated these isolates belong to a unique cluster of C. perfringens. Overall, these isolates carrying a variant functional cpe gene and iota toxin genes represent unique type E strains.

  2. Review Over a 3-Year Period of European Union Proficiency Tests for Detection of Staphylococcal Enterotoxins in Food Matrices.

    Science.gov (United States)

    Nia, Yacine; Mutel, Isabelle; Assere, Adrien; Lombard, Bertrand; Auvray, Frederic; Hennekinne, Jacques-Antoine

    2016-04-13

    Staphylococcal food poisoning outbreaks are a major cause of foodborne illnesses in Europe and their notifications have been mandatory since 2005. Even though the European regulation on microbiological criteria for food defines a criterion on staphylococcal enterotoxin (SE) only in cheese and dairy products, European Food Safety Authority (EFSA) data reported that various types of food matrices are involved in staphylococcal food poisoning outbreaks. The European Screening Method (ESM) of European Union Reference Laboratory for Coagulase Positive Staphylococci (EURL CPS) was validated in 2011 for SE detection in food matrices and is currently the official method used for screening purposes in Europe. In this context, EURLCPS is annually organizing Inter-Laboratory Proficiency Testing Trials (ILPT) to evaluate the competency of the European countries' National Reference Laboratories (NRLs) to analyse SE content in food matrices. A total of 31 NRLs representing 93% of European countries participated in these ILPTs. Eight food matrices were used for ILPT over the period 2013-2015, including cheese, freeze-dried cheese, tuna, mackerel, roasted chicken, ready-to-eat food, milk, and pastry. Food samples were spiked with four SE types (i.e., SEA, SEC, SED, and SEE) at various concentrations. Homogeneity and stability studies showed that ILPT samples were both homogeneous and stable. The analysis of results obtained by participants for a total of 155 blank and 620 contaminated samples allowed for evaluation of trueness (>98%) and specificity (100%) of ESM. Further to the validation study of ESM carried out in 2011, these three ILPTs allowed for the assessment of the proficiency of the NRL network and the performance of ESM on a large variety of food matrices and samples. The ILPT design presented here will be helpful for the organization of ILPT on SE detection by NRLs or other expert laboratories.

  3. Review Over a 3-Year Period of European Union Proficiency Tests for Detection of Staphylococcal Enterotoxins in Food Matrices

    Directory of Open Access Journals (Sweden)

    Yacine Nia

    2016-04-01

    Full Text Available Staphylococcal food poisoning outbreaks are a major cause of foodborne illnesses in Europe and their notifications have been mandatory since 2005. Even though the European regulation on microbiological criteria for food defines a criterion on staphylococcal enterotoxin (SE only in cheese and dairy products, European Food Safety Authority (EFSA data reported that various types of food matrices are involved in staphylococcal food poisoning outbreaks. The European Screening Method (ESM of European Union Reference Laboratory for Coagulase Positive Staphylococci (EURL CPS was validated in 2011 for SE detection in food matrices and is currently the official method used for screening purposes in Europe. In this context, EURLCPS is annually organizing Inter-Laboratory Proficiency Testing Trials (ILPT to evaluate the competency of the European countries’ National Reference Laboratories (NRLs to analyse SE content in food matrices. A total of 31 NRLs representing 93% of European countries participated in these ILPTs. Eight food matrices were used for ILPT over the period 2013–2015, including cheese, freeze-dried cheese, tuna, mackerel, roasted chicken, ready-to-eat food, milk, and pastry. Food samples were spiked with four SE types (i.e., SEA, SEC, SED, and SEE at various concentrations. Homogeneity and stability studies showed that ILPT samples were both homogeneous and stable. The analysis of results obtained by participants for a total of 155 blank and 620 contaminated samples allowed for evaluation of trueness (>98% and specificity (100% of ESM. Further to the validation study of ESM carried out in 2011, these three ILPTs allowed for the assessment of the proficiency of the NRL network and the performance of ESM on a large variety of food matrices and samples. The ILPT design presented here will be helpful for the organization of ILPT on SE detection by NRLs or other expert laboratories.

  4. Influence of carvacrol and thymol on the physiological attributes, enterotoxin production and surface characteristics of Staphylococcus aureus strains isolated from foods

    Directory of Open Access Journals (Sweden)

    E.L. Souza

    2013-01-01

    Full Text Available This study evaluated the influence of the phenolic compounds carvacrol (CAR and thymol (THY on some physiological characteristics and on the modulation of the secretion of some staphylococcal virulence factors, that is, coagulase and enterotoxin. This study also investigated possible mechanisms for the establishment of the anti-staphylococcal activity of these compounds. Sublethal concentrations (0.3 and 0.15 µL/mL of CAR and THY inhibited the activity of the enzymes coagulase and lipase and led to a decrease in salt tolerance. At the tested sublethal concentrations, both CAR and THY led to a total suppression of enterotoxin production. The loss of a 260-nm-absorbing material and an efflux of potassium ions occurred immediately after the addition of CAR and THY at 0.6 and 1.2 µL/mL and increased up to 120 min of exposure. Electron microscopy of cells exposed to CAR and THY (0.6 µL/mL revealed that individual cells appeared to be deformed, with projections of cellular material. The observations of leakage of cellular material and an altered cell surface suggest that gross damage to a cell's cytoplasmic membrane, which results in a disruption in protein secretion, could be responsible for the anti-staphylococcal properties of CAR and THY.

  5. 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...

  6. Chromosomal features of Escherichia coli serotype O2:K2, an avian pathogenic E. coli

    DEFF Research Database (Denmark)

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

    2017-01-01

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

  7. Growth inhibition of Staphylococcus aureus and escherichia coli strains by neutralizing IgY antibodies from ostrich egg yolk

    Directory of Open Access Journals (Sweden)

    Fernando Luiz Tobias

    2012-06-01

    Full Text Available Ostrich raising around the world have some key factors and farming profit depend largely on information and ability of farmers to rear these animals. Non fertilized eggs from ostriches are discharged in the reproduction season. Staphylococcus aureus and Escherichia coli are microorganisms involved in animal and human diseases. In order to optimize the use of sub products of ostrich raising, non fertilized eggs of four selected birds were utilized for development of polyclonal IgY antibodies. The birds were immunized (200ug/animal with purified recombinant staphylococcal enterotoxin C (recSEC and synthetic recRAP, both derived from S. aureus, and recBFPA and recEspB involved in E. coli pathogenicity, diluted in FCA injected in the braquial muscle. Two subsequent immunization steps with 21 days intervals were repeated in 0,85% saline in FIA. Blood and eggs samples were collected before and after immunization steps. Egg yolk immunoglobulins were purified by precipitation with 19% sodium sulfate and 20% ammonium sulphate methodologies. Purified IgY 50µL aliquots were incubated in 850µL BHI broth containing 50µL inoculums of five strains of S. aureus and five strains of E.coli during four hours at 37ºC. Growth inhibition was evaluated followed by photometry reading (DO550nm. Egg yolk IgY preparation from hiperimmunized birds contained antibodies that inhibited significantly (p<0,05 growth of strains tested. Potential use of ostrich IgY polyclonal antibodies as a diagnostic and therapeutic tool is proposed for diseased animals.

  8. Diarrheagenic Escherichia coli Markers and Phenotypes among Fecal E. coli Isolates Collected from Nicaraguan Infants ▿

    OpenAIRE

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

    2010-01-01

    We analyzed the prevalence of diarrheagenic Escherichia coli (DEC) markers and common phenotypes in 2,164 E. coli isolates from 282 DEC-positive samples. Enteropathogenic E. coli (EPEC) and enteroaggregative E. coli (EAEC) were very diverse and were not correlated with diarrhea. Enterotoxigenic E. coli (ETEC) estA and enterohemorrhagic E. coli (EHEC) belonged to a few phenotypes and were significantly correlated with diarrhea.

  9. Structure of the superantigen staphylococcal enterotoxin B in complex with TCR and peptide-MHC demonstrates absence of TCR-peptide contacts.

    Science.gov (United States)

    Rödström, Karin E J; Elbing, Karin; Lindkvist-Petersson, Karin

    2014-08-15

    Superantigens are immune-stimulatory toxins produced by Staphylococcus aureus, which are able to interact with host immune receptors to induce a massive release of cytokines, causing toxic shock syndrome and possibly death. In this article, we present the x-ray structure of staphylococcal enterotoxin B (SEB) in complex with its receptors, the TCR and MHC class II, forming a ternary complex. The structure, in combination with functional analyses, clearly shows how SEB adopts a wedge-like position when binding to the β-chain of TCR, allowing for an interaction between the α-chain of TCR and MHC. Furthermore, the binding mode also circumvents contact between TCR and the peptide presented by MHC, which enables SEB to initiate a peptide-independent activation of T cells. Copyright © 2014 by The American Association of Immunologists, Inc.

  10. Antimicrobial resistance and detection of the mecA gene besides enterotoxin-encoding genes among coagulase-negative Staphylococci isolated from clam meat of Anomalocardia brasiliana.

    Science.gov (United States)

    Batista, Jacqueline Ellen Camelo; Ferreira, Ewerton Lucena; Nascimento, Danielle Cristina de Oliveira; Ventura, Roberta Ferreira; de Oliveira, Wagner Luis Mendes; Leal, Nilma Cintra; Lima-Filho, José Vitor

    2013-12-01

    The marine clam Anomalocardia brasiliana is a candidate as a sentinel animal to monitor the contamination levels of coliforms in shellfish-harvesting areas of Brazil's northeastern region. The aim of the present study was to search enterotoxin-encoding genes plus the mecA gene among coagulase-negative staphylococci (CNS) isolates from shellfish meats of A. brasiliana. The specimen clam (n=48; 40 clams per sample) was collected during low tide in the bay area of Mangue Seco from April through June 2009, and random samples of chilled and frozen shelled clam meat (n=33; 250 g per sample) were obtained from retail shops from January through March 2012. Seventy-nine CNS isolates were identified, including Staphylococcus xylosus, S. cohnii spp. urealyticus, S. sciuri, and S. lentus. A high percentage of isolates resistant to erythromycin (58.5%), penicillin (51.2%), and tetracycline (43.9%), and the fluoroquinolones levofloxacin (39%) and ciprofloxacin (34.1%) were recorded from those environmental samples. Isolates from retail shops were particularly resistant to oxacillin (55.3%) and penicillin (36.8%). All CNS resistant to oxacillin and/or cefoxitin were positive for the presence of the mecA gene, but phenotypically susceptible to vancomycin. Also, the enterotoxin-encoding genes seg and seh were detected through multiplex-polymerase chain reaction in 77.7% and 88.8% of the isolates from environmental samples, versus 90.5% and 100% of the isolates from retail shops, respectively. The data reveal the risk to public health due to consuming raw or undercooked shellfish containing enterotoxigenic plus methicillin-resistant CNS.

  11. Molecular and epidemiological characterization of staphylococcal foodborne outbreak of Staphylococcus aureus harboring seg, sei, sem, sen, seo, and selu genes without production of classical enterotoxins.

    Science.gov (United States)

    Umeda, Kaoru; Nakamura, Hiromi; Yamamoto, Kaori; Nishina, Nobuko; Yasufuku, Kiyoshi; Hirai, Yuki; Hirayama, Teruo; Goto, Kaoru; Hase, Atsushi; Ogasawara, Jun

    2017-09-01

    Staphylococcal food poisoning is the result of consumption of food contaminated with staphylococcal enterotoxins (SEs) produced by Staphylococcus aureus. To date, 23 SEs and SE-like enterotoxins (SEls) have been described in the literature. They are divided into classical SEs (SEA-SEE) and new SE/SEls (SEG-SElX). Some have proved to be foodborne-inducible, but others remain unidentified. In May 2016, at an elderly group home in Osaka city, Japan, an outbreak from foodborne pathogens occurred among lunch party participants. Within 2h 30min to 4h 40min, 15 of 53 participants presented gastrointestinal symptoms of vomiting, diarrhea, and nausea. A subsequent laboratory investigation detected S. aureus from most stool samples from patients, several left-over food items, a kitchen swab, and hand swabs from two food handlers. Classical SEs was not detected from S. aureus isolates or left-over food items. From examination for the presence of SE/SEl genes of 20 kinds by PCR, seg, sei, sem, sen, seo, and selu genes were detected in almost all isolates. These isolates exhibited identical or closely related types by coagulase type (type VII), Sma I digested pulsed-field gel electrophoresis analysis and multi-locus sequence typing (MLST-CC45 lineage). These results suggest that the foodborne outbreak was caused by S. aureus harboring seg, sei, sem, sen, seo, and selu genes without production of classical SEs. Additionally, some S. aureus isolates from human nasal swabs and healthy human feces harboring seg, sei, sem, sen, seo, and selu genes without production of classical SEs were classified into CC45 lineage using MLST. These findings suggest new SE/SEls as a potential cause of foodborne outbreaks. Copyright © 2017. Published by Elsevier B.V.

  12. Positive Regulation of Staphylococcal Enterotoxin H by Rot (Repressor of Toxin) Protein and Its Importance in Clonal Complex 81 Subtype 1 Lineage-Related Food Poisoning.

    Science.gov (United States)

    Sato'o, Yusuke; Hisatsune, Junzo; Nagasako, Yuria; Ono, Hisaya K; Omoe, Katsuhiko; Sugai, Motoyuki

    2015-11-01

    We previously demonstrated the clonal complex 81 (CC81) subtype 1 lineage is the major staphylococcal food poisoning (SFP)-associated lineage in Japan (Y. Sato'o et al., J Clin Microbiol 52:2637-2640, 2014, http://dx.doi.org/10.1128/JCM.00661-14). Strains of this lineage produce staphylococcal enterotoxin H (SEH) in addition to SEA. However, an evaluation of the risk for the recently reported SEH has not been sufficiently conducted. We first searched for staphylococcal enterotoxin (SE) genes and SE proteins in milk samples that caused a large SFP outbreak in Japan. Only SEA and SEH were detected, while there were several SE genes detected in the samples. We next designed an experimental model using a meat product to assess the productivity of SEs and found that only SEA and SEH were detectably produced in situ. Therefore, we investigated the regulation of SEH production using a CC81 subtype 1 isolate. Through mutant analysis of global regulators, we found the repressor of toxin (Rot) functioned oppositely as a stimulator of SEH production. SEA production was not affected by Rot. seh mRNA expression correlated with rot both in media and on the meat product, and the Rot protein was shown to directly bind to the seh promoter. The seh promoter sequence was predicted to form a loop structure and to hide the RNA polymerase binding sequences. We propose Rot binds to the promoter sequence of seh and unfolds the secondary structure that may lead the RNA polymerase to bind the promoter, and then seh mRNA transcription begins. This alternative Rot regulation for SEH may contribute to sufficient toxin production by the CC81 subtype 1 lineage in foods to induce SFP. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  13. [The staphylococcal enterotoxin burden determines the ultrastructure of ciliated epithelia and inflammatory changes in maxillary sinus mucosa of rabbits].

    Science.gov (United States)

    Wei, Hongqi; Zhu, Zhengwen; Cao, Zhongsheng; Liu, Zhiyong; Wu, Xiaofan; Yuan, Hui

    2014-12-01

    To investigate the ultrastructure of ciliated epithelia and inflammatory changes upon repeated exposure to staphylococcal enterotoxin A (SEA) of different concentrations in the maxillary sinus mucosa of rabbits. The rabbits were randomly divided into 2 groups (24 rabbits per group): low-dose SEA group and high-dose SEA group. The low-dose SEA group and high-dose SEA group received daily injections of 0.6 ng of SEA (2 ml) and 60 ng of SEA (2 ml) into the left maxillary sinus of rabbits for 28 days, respectively. Concurrent treatment of the right maxillary sinus with normal saline was used as control. Six rabbits chosen randomly in two groups were examined by computed tomography (CT) scans and then sacrificed to obtain the sinus mucosa from the two-side of maxillary sinuses for histological assessment on days 3, 7, 14 and 28. To characterize the inflammatory changes of the sinus mucosa examined using light microscope, hematoxylin and eosin (HE) and toluidine blue staining was performed. Scanning and transmission electron microscopy were performed to observe ultrastructure of ciliated epithelia in the maxillary sinus mucosa. SPSS 13.0 software was used to analyze the data. On days 14 and 28, CT images showed opacification of the left maxillary sinus in the high-dose SEA group. The percentage of epithelial disruption was (22.73 ± 5.72) % and (30.79 ± 4.30)% in the high-dose SEA group respectively, and were significantly greater than those in the low-dose SEA group (5.12% ± 1.98% and 5.38% ± 1.64%, q value was 10.079 and 19.132) and control group (4.08% ± 1.29% and 4.81% ± 1.62%, q value was 11.016 and 19.592, respectively, all P microscope, loss of cilia was observed, a few compound cilia and cytoplasmic protrusion were found, an obvious stretching of the endoplasmic reticulum and an obvious turgescence of the mitochondria was also observed. However, in the low-dose SEA group on days 14 and 28, CT scan of the left maxillary sinus showed transparency; light

  14. Photoreactivating enzyme from Escherichia coli

    International Nuclear Information System (INIS)

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

    1977-01-01

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

  15. Photoreactivating enzyme from Escherichia coli

    Energy Technology Data Exchange (ETDEWEB)

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

    1977-05-01

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

  16. Expression in E. coli systems

    DEFF Research Database (Denmark)

    Krogsdam, Anne-M; Kristiansen, Karsten; Nøhr, Jane

    2003-01-01

    intracellularly in soluble form. In E. coli, proteins containing disulfide bonds are best produced by secretion because the disulfide forming foldases reside in the periplasm. Likewise, a correct N-terminus is more likely to be obtained upon secretion. Moreover, potentially toxic proteins are more likely......Owing to cost advantage, speed of production, and often high product yield (up to 50% of total cell protein), expression in Escherichia coli is generally the first choice when attempting to express a recombinant protein. Expression systems exist to produce recombinant protein intracellularly...

  17. Experimental evolution of E. coli

    Science.gov (United States)

    Zhang, Mengshi

    The evolution from unicellular to multicellular behavior is an essential step in the history of life. Our aim is to investigate the emergence of collective behavior in the model organism Escherichia coli (E. coli) and its selection advantages, such as better utilization of public goods. Our preliminary results suggest that the evolution of collective behavior may be a natural response to stressed conditions. Mailing address: Room 306 Science Centre North Block, The Chinese University of Hong Kong, Shatin, N.T. Hong Kong SAR. Phone: +852-3943-6354. Fax: +852-2603-5204. E-mail: mengshi0928@gmail.com.

  18. The oxygen effect in E. coli cells

    International Nuclear Information System (INIS)

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

    1982-01-01

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

  19. Actions and advice in coli

    DEFF Research Database (Denmark)

    Knoche, Hendrik; Jamadagni, HS; Rao, PR Sheshagiri

    2015-01-01

    To improve their agricultural output, farmers require timely and contextualized information and advice. Relevant information and advice provided by trusted peers represents a promising approach. We present the considerations for the design of coli, an agricultural information network on touch scr...

  20. Infektionen mit darmpathogenen Escherichia coli.

    NARCIS (Netherlands)

    Friedrich, Alexander; Stein, Jürgen; Dignass, Axel

    2001-01-01

    E. coli ist ein wesentlicher Bestandteil der physiologischen Darmflora des Menschen. Die üblicherweise im Darm vorkommenden Kolibakterien sind apathogen und für den Menschen eher nützlich (Sonnenborn u. Greinwald 1990). Allerdings kennen wir bei dieser Bakterienspezies auch ein breites Spektrum von

  1. 76 FR 20542 - Escherichia coli

    Science.gov (United States)

    2011-04-13

    ... beef, Escherichia coli and coliphages were found in chicken, fresh pork, fresh oyster, fresh mushrooms, lettuce, chicken pot pie, biscuit dough, deli loaf, deli roasted turkey, and package roasted chicken... surfaces, and in foods such as ground beef, pork sausage, chicken, oysters, cheese, fresh mushrooms, and...

  2. ESCHERICHIA COLI AND STAPHYLOCOCCUS AUREUS

    African Journals Online (AJOL)

    DR. AMINU

    ABSTRACT. The bio-effects of the ethanol extracts from the leaf and stem of Momordica charantia were studied with the view to ascertain the medical usefulness ascribed to the plant by the locals. The plant parts, stem and leaf, revealed remarkable activity against Escherichia coli and Staphlococcus aureus. The leaves ...

  3. Conjugal Pairing in Escherichia Coli

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 13; Issue 8. Conjugal Pairing in Escherichia Coli. Joshua Lederberg. Classics Volume 13 Issue 8 August 2008 pp 793-794. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/013/08/0793-0794 ...

  4. Escherichia coli as a probiotic?

    NARCIS (Netherlands)

    Jansen, GJ; Wildeboer-Veloo, ACM; van der Waaij, D; Degener, JE

    1998-01-01

    The influence of oral treatment with a suspension of non-pathogenic Escherichia coli cells (commercially available as: Symbioflor II(R)) on the morphological composition of the gut microflora and on the systemic humoral immune response (the IgG-, IgA- and IgM-isotype) against the bacterial cells in

  5. Expression in E. coli systems

    DEFF Research Database (Denmark)

    Krogsdam, Anne-M; Kristiansen, Karsten; Nøhr, Jane

    2003-01-01

    intracellularly in soluble form. In E. coli, proteins containing disulfide bonds are best produced by secretion because the disulfide forming foldases reside in the periplasm. Likewise, a correct N-terminus is more likely to be obtained upon secretion. Moreover, potentially toxic proteins are more likely...

  6. CfaE tip mutations in enterotoxigenic Escherichia coli CFA/I fimbriae define critical human intestinal binding sites.

    Science.gov (United States)

    Baker, K K; Levine, M M; Morison, J; Phillips, A; Barry, E M

    2009-05-01

    Enterotoxigenic Escherichia coli (ETEC) use colonization factors to attach to the human intestinal mucosa, followed by enterotoxin expression that induces net secretion and diarrhoeal illness. ETEC strain H10407 expresses CFA/I fimbriae, which are composed of multiple CfaB structural subunits and a CfaE tip subunit. Currently, the contribution of these individual fimbrial subunits in intestinal binding remains incompletely defined. To identify the role of CfaE in attachment in the native ETEC background, an R181A single-amino-acid substitution was introduced by recombination into the H10407 genome. The substitution of R181A eliminated haemagglutination and binding of intestinal mucosa biopsies in in vitro organ culture assays, without loss of CFA/I fimbriae expression. Wild-type in trans plasmid-expressed cfaE restored the binding phenotype. In contrast, in trans expression of cfaE containing amino acid 181 substitutions with similar amino acids, lysine, methionine and glutamine did not restore the binding phenotype, indicating that the loss of the binding phenotype was due to localized areas of epitope disruption. R181 appears to have an irreplaceable role in the formation of a receptor-binding feature on CFA/I fimbriae. The results specifically indicate that the CfaE tip protein is a required binding factor in CFA/I-mediated ETEC colonization, making it a potentially important vaccine antigen. © 2009 Blackwell Publishing Ltd.

  7. 99mTechnetium labelled Escherichia coli

    International Nuclear Information System (INIS)

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

    1999-01-01

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

  8. Human Meningitis-Associated Escherichia coli

    Science.gov (United States)

    KIM, KWANG SIK

    2016-01-01

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

  9. Pneumatosis Coli Mimicking Colorectal Cancer

    Directory of Open Access Journals (Sweden)

    Teresa Jacob

    2014-01-01

    Full Text Available Pneumatosis coli (PC is a rare condition of the gastrointestinal tract involving extraluminal gas confined within the bowel wall. We report the case of a 40-year-old gentleman presenting clinically and endoscopically with suspected colorectal cancer. In light of the patient’s red flag symptoms, and carpet of polyps seen endoscopically, surgical management by an anterior resection was performed with the patient making a successful recovery. Histological analysis of the resected specimen confirmed pneumatosis coli with no evidence of colonic neoplasia. Although PC can be an incidental finding in asymptomatic patients and considered a benign condition, it can also present as a life-threatening emergency with bowel necrosis and obstruction requiring emergency surgical intervention. Also, when PC mimics malignancy, surgical management is the most appropriate step to ensure that the diagnosis of cancer is not missed.

  10. Multiplex PCR Assay for Identification of Human Diarrheagenic Escherichia coli

    OpenAIRE

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

    2003-01-01

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

  11. The adenomatous polyposis coli protein.

    OpenAIRE

    Näthke, I S

    1999-01-01

    Mutations in the adenomatous polyposis coli (APC) gene are associated with most colorectal cancers. The APC protein has been implicated in many aspects of tumour development. This article will discuss recent data suggesting that APC may have multiple functions in the cell. First, APC is a component of the Wnt signalling pathway; second, APC may have a role in cell migration; finally, APC may regulate proliferation and apoptosis.

  12. Assessment of Enterotoxin Production and Cross-Contamination of Staphylococcus aureus between Food Processing Materials and Ready-To-Eat Cooked Fish Paste.

    Science.gov (United States)

    Tango, Charles Nkufi; Hong, Sung-Sam; Wang, Jun; Oh, Deog-Hwan

    2015-12-01

    This study evaluated Staphylococcus aureus growth and subsequent staphylococcal enterotoxin A production in tryptone soy broth and on ready-to-eat cooked fish paste at 12 to 37 °C, as well as cross-contamination between stainless steel, polyethylene, and latex glove at room temperature. A model was developed using Barany and Roberts's growth model, which satisfactorily described the suitable growth of S. aureus with R(2)-adj from 0.94 to 0.99. Except at 12 °C, S. aureus cells in TSB presented a lag time lower (14.64 to 1.65 h), grew faster (0.08 to 0.31 log CFU/h) and produced SEA at lower cell density levels (5.65 to 6.44 log CFU/mL) compare to those inoculated on cooked fish paste with data of 16.920 to 1.985 h, 0.02 to 0.23 log CFU/h, and 6.19 to 7.11 log CFU/g, respectively. Staphylococcal enterotoxin type A (SEA) visual immunoassay test showed that primary SEA detection varied considerably among different storage temperature degrees and media. For example, it occurred only during exponential phase at 30 and 37 °C in TSB, but in cooked fish paste it took place at late exponential phase of S. aureus growth at 20 and 25 °C. The SEA detection test was negative on presence of S. aureus on cooked fish paste stored at 12 and 15 °C, although cell density reached level of 6.12 log CFU/g at 15 °C. Cross-contamination expressed as transfer rate of S. aureus from polyethylene surface to cooked fish paste surface was slower than that observed with steel surface to cooked fish paste under same conditions. These results provide helpful information for controlling S. aureus growth, SEA production and cross-contamination during processing of cooked fish paste. © 2015 Institute of Food Technologists®

  13. Characteristics of enterotoxin distribution, hemolysis, lecithinase, and starch hydrolysis of Bacillus cereus isolated from infant formulas and ready-to-eat foods.

    Science.gov (United States)

    Hwang, Ji-Yeon; Park, Jong-Hyun

    2015-03-01

    Bacillus cereus is a ubiquitous environmental microbe implicated as a main cause of food poisoning with various symptoms, depending on the strain type and the isolation source. In this study, the potential virulence factors and biochemical properties of B. cereus isolated from infant formulas and ready-to-eat (RTE) foods were analyzed and compared. A total of 347 B. cereus strains were isolated and identified from 687 infant food formulas and RTE food samples. All the isolates had one or more enterotoxin genes, and one-half of the strains had all 3 enterotoxin genes (hbl, nhe, and cytK) that are involved in food poisoning in humans. Here, all the 3 genes were detected in 50% of the B. cereus isolates from RTE foods and only 14% of the isolates were identified from infant formulas. The latter harbored low cytK and bceT, and very low hbl genes. Most B. cereus isolates possessed the hemolysis gene, but not the ces gene. The infant formula isolates showed stronger hemolysis activity than the other isolates. In addition, 26% of the total isolates showed low lecithinase activities and 10% showed high lecithinase activities. A greater number of isolates from the infant formula showed high lecithinase activity than those from the RTE foods. Approximately 83% of the isolates were positive and 17% were negative for starch hydrolysis. Over 90% of the RTE food isolates and only 35% of the infant formula isolates were positive for starch hydrolysis. However, all the strains possessed nhe, but their harboring patterns of hbl and cytK were significantly different. Most starch-hydrolyzing strains possessed hbl, but only 23% nonstarch-hydrolyzing isolates possessed this gene. Moreover, very low nonstarch hydrolyzing strains harbored cytK. Most nonstarch-hydrolyzing isolates showed high lecithinase and strong hemolysis activities, and very low hbl and cytK harboring. In summary, most infant formula isolates showed stronger hemolysis and higher lecithinase activities with lower

  14. A highly sensitive fluorescence resonance energy transfer aptasensor for staphylococcal enterotoxin B detection based on exonuclease-catalyzed target recycling strategy

    International Nuclear Information System (INIS)

    Wu, Shijia; Duan, Nuo; Ma, Xiaoyuan; Xia, Yu; Wang, Hongxin; Wang, Zhouping

    2013-01-01

    Graphical abstract: -- Highlights: •An ultrasensitive FRET aptasensor was developed for staphylococcal enterotoxin B determination. •SEB was recognized by SEB aptamer with high affinity and specificity. •The Mn 2+ doped NaYF 4 :Yb/Er UCNPs used as donor to quencher dye (BHQ 3 ) in new FRET. •The fluorescence intensity was prominently amplified using an exonuclease-catalyzed target recycling strategy. -- Abstract: An ultrasensitive fluorescence resonance energy transfer (FRET) bioassay was developed to detect staphylococcal enterotoxin B (SEB), a low molecular exotoxin, using an aptamer-affinity method coupled with upconversion nanoparticles (UCNPs)-sensing, and the fluorescence intensity was prominently enhanced using an exonuclease-catalyzed target recycling strategy. To construct this aptasensor, both fluorescence donor probes (complementary DNA 1 –UCNPs) and fluorescence quencher probes (complementary DNA 2 –Black Hole Quencher 3 (BHQ 3 )) were hybridized to an SEB aptamer, and double-strand oligonucleotides were fabricated, which quenched the fluorescence of the UCNPs via FRET. The formation of an aptamer–SEB complex in the presence of the SEB analyte resulted in not only the dissociation of aptamer from the double-strand DNA but also both the disruption of the FRET system and the restoration of the UCNPs fluorescence. In addition, the SEB was liberated from the aptamer–SEB complex using exonuclease I, an exonuclease specific to single-stranded DNA, for analyte recycling by selectively digesting a particular DNA (SEB aptamer). Based on this exonuclease-catalyzed target recycling strategy, an amplified fluorescence intensity could be produced using different SEB concentrations. Using optimized experimental conditions produced an ultrasensitive aptasensor for the detection of SEB, with a wide linear range of 0.001–1 ng mL −1 and a lower detection limit (LOD) of 0.3 pg mL −1 SEB (at 3σ). The fabricated aptasensor was used to measure SEB in a

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

    Directory of Open Access Journals (Sweden)

    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

  16. The Proteome of Biologically Active Membrane Vesicles from Piscirickettsia salmonis LF-89 Type Strain Identifies Plasmid-Encoded Putative Toxins

    Directory of Open Access Journals (Sweden)

    Cristian Oliver

    2017-09-01

    Full Text Available Piscirickettsia salmonis is the predominant bacterial pathogen affecting the Chilean salmonid industry. This bacterium is the etiological agent of piscirickettsiosis, a significant fish disease. Membrane vesicles (MVs released by P. salmonis deliver several virulence factors to host cells. To improve on existing knowledge for the pathogenicity-associated functions of P. salmonis MVs, we studied the proteome of purified MVs from the P. salmonis LF-89 type strain using multidimensional protein identification technology. Initially, the cytotoxicity of different MV concentration purified from P. salmonis LF-89 was confirmed in an in vivo adult zebrafish infection model. The cumulative mortality of zebrafish injected with MVs showed a dose-dependent pattern. Analyses identified 452 proteins of different subcellular origins; most of them were associated with the cytoplasmic compartment and were mainly related to key functions for pathogen survival. Interestingly, previously unidentified putative virulence-related proteins were identified in P. salmonis MVs, such as outer membrane porin F and hemolysin. Additionally, five amino acid sequences corresponding to the Bordetella pertussis toxin subunit 1 and two amino acid sequences corresponding to the heat-labile enterotoxin alpha chain of Escherichia coli were located in the P. salmonis MV proteome. Curiously, these putative toxins were located in a plasmid region of P. salmonis LF-89. Based on the identified proteins, we propose that the protein composition of P. salmonis LF-89 MVs could reflect total protein characteristics of this P. salmonis type strain.

  17. Algevir: An Expression System for Microalgae Based on Viral Vectors

    Directory of Open Access Journals (Sweden)

    Bernardo Bañuelos-Hernández

    2017-06-01

    Full Text Available The use of recombinant algae for the production of valuable compounds is opening promising biotechnological applications. However, the development of efficient expression approaches is still needed to expand the exploitation of microalgae in biotechnology. Herein, the concept of using viral expression vectors in microalgae was explored for the first time. An inducible geminiviral vector leading to Rep-mediated replication of the expression cassette allowed the production of antigenic proteins at high levels. This system, called Algevir, allows the production of complex viral proteins (GP1 from Zaire ebolavirus and bacterial toxin subunits (B subunit of the heat-labile Escherichia coli enterotoxin, which retained their antigenic activity. The highest achieved yield was 1.25 mg/g fresh biomass (6 mg/L of culture, which was attained 3 days after transformation. The Algevir system allows for a fast and efficient production of recombinant proteins, overcoming the difficulties imposed by the low yields and unstable expression patterns frequently observed in stably transformed microalgae at the nuclear level; as well as the toxicity of some target proteins.

  18. Bystander protein protects potential vaccine-targeting ligands against intestinal proteolysis.

    Science.gov (United States)

    Reuter, Fabian; Bade, Steffen; Hirst, Timothy R; Frey, Andreas

    2009-07-20

    Endowing mucosal vaccines with ligands that target antigen to mucosal lymphoid tissues may improve immunization efficacy provided that the ligands withstand the proteolytic environment of the gastro-intestinal tract until they reach their destination. Our aim was to investigate whether and how three renowned ligands - Ulex europaeus agglutinin I and the B subunits of cholera toxin and E. coli heat-labile enterotoxin - master this challenge. We assessed the digestive power of natural murine intestinal fluid (natIF) using assays for trypsin, chymotrypsin and pancreatic elastase along with a test for nonspecific proteolysis. The natIF was compared with simulated murine intestinal fluid (simIF) that resembled the trypsin, chymotrypsin and elastase activities of its natural counterpart but lacked or contained albumins as additional protease substrates. The ligands were exposed to the digestive fluids and degradation was determined. The studies revealed that (i) the three pancreatic endoproteases constitute only one third of the total protease activity of natIF and (ii) the ligands resist proteolysis in natIF and protein-enriched simIF over 3 h but (iii) are partially destroyed in simIF that lacks additional protease substrate. We assume that the proteins of natIF are preferred substrates for the intestinal proteases and thus can protect vaccine-targeting ligands from destruction.

  19. [A study on the construction, expression and immunosterility of Lagurus laguru zona pellucida 3 DNA vaccine pVAX1-sig-LTB-lZP3-C3d3].

    Science.gov (United States)

    Li, Chen-Chen; Yu, Ji-Yun; Jiang, Min; Tu, Yi-Xian; Ma, Xiao-Lin; Zhang, Fu-Chun

    2011-09-01

    To enhance the immunocontraceptive effect of Lagurus lagurus zona pellucida 3 DNA vaccine, and to achieve the prospect of application through the pVAX1-sig-LTB-lZP3-C3d3 different immunity pathway. Two adjuvant molecules were constructed into the recombinant plasmid pVAX1-sig-LTB-lZP3-C3d3 as DNA vaccine which contains Escherichia coli heat-labile enterotoxin B subunit and the molecular adjuvant 3 copies of C3d. The results of RT-PCR and western blot showed that the DNA vaccine was expressed in mRNA and protein level. The female C57BL/6 mice were immunized by three ways: intramuscular injection, intranasal or oral route.Antibody levels and types were detected by ELISA. ELISA results showed that recombinant plasmid pVAX1-sig-LTB-lZP3-C3d3 immunization induced specific IgG, IgA levels were significantly different comparing with control (Psig-LTB-lZP3-C3d3 can induce the specific immune response efficiently and enhance the immunocontraceptive effects.

  20. Algevir: An Expression System for Microalgae Based on Viral Vectors

    Science.gov (United States)

    Bañuelos-Hernández, Bernardo; Monreal-Escalante, Elizabeth; González-Ortega, Omar; Angulo, Carlos; Rosales-Mendoza, Sergio

    2017-01-01

    The use of recombinant algae for the production of valuable compounds is opening promising biotechnological applications. However, the development of efficient expression approaches is still needed to expand the exploitation of microalgae in biotechnology. Herein, the concept of using viral expression vectors in microalgae was explored for the first time. An inducible geminiviral vector leading to Rep-mediated replication of the expression cassette allowed the production of antigenic proteins at high levels. This system, called Algevir, allows the production of complex viral proteins (GP1 from Zaire ebolavirus) and bacterial toxin subunits (B subunit of the heat-labile Escherichia coli enterotoxin), which retained their antigenic activity. The highest achieved yield was 1.25 mg/g fresh biomass (6 mg/L of culture), which was attained 3 days after transformation. The Algevir system allows for a fast and efficient production of recombinant proteins, overcoming the difficulties imposed by the low yields and unstable expression patterns frequently observed in stably transformed microalgae at the nuclear level; as well as the toxicity of some target proteins. PMID:28713333

  1. Immune responses of a chimaeric protein vaccine containing Mycoplasma hyopneumoniae antigens and LTB against experimental M. hyopneumoniae infection in pigs.

    Science.gov (United States)

    Marchioro, Silvana B; Sácristan, Rubén Del Pozo; Michiels, Annelies; Haesebrouck, Freddy; Conceição, Fabricio R; Dellagostin, Odir A; Maes, Dominiek

    2014-08-06

    A recombinant chimaeric protein containing three Mycoplasma hyopneumoniae antigens (C-terminal portion of P97, heat shock protein P42, and NrdF) fused to an adjuvant, the B subunit of heat-labile enterotoxin of Escherichia coli (LTB), was used to immunize pigs against enzootic pneumonia. The systemic and local immune responses, as well as the efficacy of the chimaeric protein in inducing protection against experimental M. hyopneumoniae infection were evaluated. In total, 60 male piglets, purchased from a M. hyopneumoniae-free herd, at 4 weeks of age were randomly allocated to six different experimental groups of 10 animals each: recombinant chimaeric protein by intramuscular (IM) (1) or intranasal (IN) (2) administration, commercial bacterin by IM administration (3), and the adjuvant LTB by IM (4, control group A) or IN (5, control group B) administration. All groups were immunized at 24 and 38 days of age and challenged at 52 days of age. The sixth group that was not challenged was used as the negative control (IN [n=5] or IM [n=5] administration of the LTB adjuvant). Compared with the non-challenged group, administration of the chimaeric protein induced significant (Phyopneumoniae infection in pigs. This lack of effectiveness points towards the need for further studies to improve the efficacy of this subunit-based vaccine approach. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. An adenovirus vectored mucosal adjuvant augments protection of mice immunized intranasally with an adenovirus-vectored foot-and-mouth disease virus subunit vaccine.

    Science.gov (United States)

    Alejo, Diana M; Moraes, Mauro P; Liao, Xiaofen; Dias, Camila C; Tulman, Edan R; Diaz-San Segundo, Fayna; Rood, Debra; Grubman, Marvin J; Silbart, Lawrence K

    2013-04-26

    Foot-and-mouth disease virus (FMDV) is a highly contagious pathogen that causes severe morbidity and economic losses to the livestock industry in many countries. The oral and respiratory mucosae are the main ports of entry of FMDV, so the stimulation of local immunity in these tissues may help prevent initial infection and viral spread. E. coli heat-labile enterotoxin (LT) has been described as one of the few molecules that have adjuvant activity at mucosal surfaces. The objective of this study was to evaluate the efficacy of replication-defective adenovirus 5 (Ad5) vectors encoding either of two LT-based mucosal adjuvants, LTB or LTR72. These vectored adjuvants were delivered intranasally to mice concurrent with an Ad5-FMDV vaccine (Ad5-A24) to assess their ability to augment mucosal and systemic humoral immune responses to Ad5-A24 and protection against FMDV. Mice receiving Ad5-A24 plus Ad5-LTR72 had higher levels of mucosal and systemic neutralizing antibodies than those receiving Ad5-A24 alone or Ad5-A24 plus Ad5-LTB. The vaccine plus Ad5-LTR72 group also demonstrated 100% survival after intradermal challenge with a lethal dose of homologous FMDV serotype A24. These results suggest that Ad5-LTR72 could be used as an important tool to enhance mucosal and systemic immunity against FMDV and potentially other pathogens with a common route of entry. Copyright © 2013 Elsevier Ltd. All rights reserved.

  3. The Proteome of Biologically Active Membrane Vesicles from Piscirickettsia salmonis LF-89 Type Strain Identifies Plasmid-Encoded Putative Toxins.

    Science.gov (United States)

    Oliver, Cristian; Hernández, Mauricio A; Tandberg, Julia I; Valenzuela, Karla N; Lagos, Leidy X; Haro, Ronie E; Sánchez, Patricio; Ruiz, Pamela A; Sanhueza-Oyarzún, Constanza; Cortés, Marcos A; Villar, María T; Artigues, Antonio; Winther-Larsen, Hanne C; Avendaño-Herrera, Ruben; Yáñez, Alejandro J

    2017-01-01

    Piscirickettsia salmonis is the predominant bacterial pathogen affecting the Chilean salmonid industry. This bacterium is the etiological agent of piscirickettsiosis, a significant fish disease. Membrane vesicles (MVs) released by P. salmonis deliver several virulence factors to host cells. To improve on existing knowledge for the pathogenicity-associated functions of P. salmonis MVs, we studied the proteome of purified MVs from the P. salmonis LF-89 type strain using multidimensional protein identification technology. Initially, the cytotoxicity of different MV concentration purified from P. salmonis LF-89 was confirmed in an in vivo adult zebrafish infection model. The cumulative mortality of zebrafish injected with MVs showed a dose-dependent pattern. Analyses identified 452 proteins of different subcellular origins; most of them were associated with the cytoplasmic compartment and were mainly related to key functions for pathogen survival. Interestingly, previously unidentified putative virulence-related proteins were identified in P. salmonis MVs, such as outer membrane porin F and hemolysin. Additionally, five amino acid sequences corresponding to the Bordetella pertussis toxin subunit 1 and two amino acid sequences corresponding to the heat-labile enterotoxin alpha chain of Escherichia coli were located in the P. salmonis MV proteome. Curiously, these putative toxins were located in a plasmid region of P. salmonis LF-89. Based on the identified proteins, we propose that the protein composition of P. salmonis LF-89 MVs could reflect total protein characteristics of this P. salmonis type strain.

  4. Erythrocyte and porcine intestinal glycosphingolipids recognized by F4 fimbriae of enterotoxigenic Escherichia coli.

    Science.gov (United States)

    Coddens, Annelies; Valis, Erik; Benktander, John; Ångström, Jonas; Breimer, Michael E; Cox, Eric; Teneberg, Susann

    2011-01-01

    Enterotoxigenic F4-fimbriated Escherichia coli is associated with diarrheal disease in neonatal and postweaning pigs. The F4 fimbriae mediate attachment of the bacteria to the pig intestinal epithelium, enabling an efficient delivery of diarrhea-inducing enterotoxins to the target epithelial cells. There are three variants of F4 fimbriae designated F4ab, F4ac and F4ad, respectively, having different antigenic and adhesive properties. In the present study, the binding of isolated F4ab, F4ac and F4ad fimbriae, and F4ab/ac/ad-fimbriated E. coli, to glycosphingolipids from erythrocytes and from porcine small intestinal epithelium was examined, in order to get a comprehensive view of the F4-binding glycosphingolipids involved in F4-mediated hemagglutination and adhesion to the epithelial cells of porcine intestine. Specific interactions between the F4ab, F4ac and F4ad fimbriae and both acid and non-acid glycosphingolipids were obtained, and after isolation of binding-active glycosphingolipids and characterization by mass spectrometry and proton NMR, distinct carbohydrate binding patterns were defined for each fimbrial subtype. Two novel glycosphingolipids were isolated from chicken erythrocytes, and characterized as GalNAcα3GalNAcß3Galß4Glcß1Cer and GalNAcα3GalNAcß3Galß4GlcNAcß3Galß4Glcß1Cer. These two compounds, and lactosylceramide (Galß4Glcß1Cer) with phytosphingosine and hydroxy fatty acid, were recognized by all three variants of F4 fimbriae. No binding of the F4ad fimbriae or F4ad-fimbriated E. coli to the porcine intestinal glycosphingolipids occurred. However, for F4ab and F4ac two distinct binding patterns were observed. The F4ac fimbriae and the F4ac-expressing E. coli selectively bound to galactosylceramide (Galß1Cer) with sphingosine and hydroxy 24:0 fatty acid, while the porcine intestinal glycosphingolipids recognized by F4ab fimbriae and the F4ab-fimbriated bacteria were characterized as galactosylceramide, sulfatide (SO(3)-3Galß1Cer), sulf

  5. Distinct cytokine profiles of circulating mononuclear cells stimulated with Staphylococcus aureus enterotoxin A in vitro during early and late episodes of chronic osteomyelitis

    Directory of Open Access Journals (Sweden)

    Gabriella Freitas Ferreira

    2012-05-01

    Full Text Available We investigated the cytokine profile of peripheral mononuclear cells from chronic osteomyelitis (OST patients following in vitro stimulation with staphylococcal enterotoxin A (SEA. We demonstrate that stimulation with SEA induced prominent lymphocyte proliferation and high levels of tumour necrosis factor (TNF-α, interleukin (IL-4 and IL-10 secretion in both OST and non-infected individuals (NI. Even though stimulation with SEA had no impact on IL-6 production in either patient group, the baseline level of IL-6 production by cells from OST patients was always significantly less than that produced by cells from NI. After classifying the osteomyelitic episodes based on the time after the last reactivation event as "early" (1-4 months or "late" osteomyelitis (5-12 months, we found that increased levels of TNF-α and IL-4 in combination with decreased levels of IL-6 were observed in the early episodes. By contrast, increased levels of IL-10, IL-2 and IL-6 were hallmarks of late episodes. Our data demonstrate that early osteomyelitic episodes are accompanied by an increased frequency of "high producers" of TNF-α and IL-4, whereas late events are characterised by increased frequencies of "high producers" of IL-10, IL-6 and IL-2. These findings demonstrate the distinct cytokine profiles in chronic osteomyelitis, with a distinct regulation of IL-6 production during early and late episodes.

  6. Frequency of enterotoxins, toxic shock syndrome toxin-1, and biofilm formation genes in Staphylococcus aureus isolates from cows with mastitis in the Northeast of Brazil.

    Science.gov (United States)

    Costa, F N; Belo, N O; Costa, E A; Andrade, G I; Pereira, L S; Carvalho, I A; Santos, R L

    2018-06-01

    Staphylococcus aureus is among the microorganisms more frequently associated with subclinical bovine mastitis. S. aureus may produce several virulence factors. This study aimed at determining the frequency of virulence factors such as enterotoxins, toxic shock syndrome toxin 1, and ica adhesion genes. In addition, we assessed antimicrobial drug resistance in S. aureus isolated from clinical and subclinical cases of mastitis. A total of 88 cows with clinical or subclinical mastitis were sampled, resulting in 38 S. aureus isolates, from which 25 (65.78%) carried toxin genes, including seb, sec, sed, tst, and icaD adhesion gene. These S. aureus isolates belong to 21 ribotypes and three S. aureus strains belonged to the same ribotype producing ica adhesion gene. Approximately 90% of S. aureus strains obtained in our study demonstrated multiple resistance to different antimicrobial agents. The most efficacious antimicrobial agents against the isolates were gentamicin, amoxicillin, and norfloxacin. Gentamicin was the most efficacious agent inhibiting 78.95% of the S. aureus isolates. The least efficacious were penicillin, streptomycin, and ampicillin. Our results can help in understanding the relationship between virulence factors and subclinical mastitis caused by S. aureus. Further research about diversity of S. aureus isolates and genes responsible for the pathogenicity of subclinical mastitis is essential.

  7. Chimeric anti-staphylococcal enterotoxin B antibodies and lovastatin act synergistically to provide in vivo protection against lethal doses of SEB.

    Directory of Open Access Journals (Sweden)

    Mulualem E Tilahun

    Full Text Available Staphylococcal enterotoxin B (SEB is one of a family of toxins secreted by Staphylococcus aureus that act as superantigens, activating a large fraction of the T-cell population and inducing production of high levels of inflammatory cytokines that can cause toxic shock syndrome (TSS and death. Extracellular engagement of the TCR of T-cells and class II MHC of antigen presenting cells by SEB triggers the activation of many intracellular signaling processes. We engineered chimeric antibodies to block the extracellular engagement of cellular receptors by SEB and used a statin to inhibit intracellular signaling. Chimeric human-mouse antibodies directed against different neutralizing epitopes of SEB synergistically inhibited its activation of human T-cells in vitro. In the in vivo model of lethal toxic shock syndrome (TSS in HLA-DR3 transgenic mice, two of these antibodies conferred significant partial protection when administered individually, but offered complete protection in a synergistic manner when given together. Similarly, in vivo, lovastatin alone conferred only partial protection from TSS similar to single anti-SEB antibodies. However, used in combination with one chimeric neutralizing anti-SEB antibody, lovastatin provided complete protection against lethal TSS in HLA-DR3 transgenic mice. These experiments demonstrate that in vivo protection against lethal doses of SEB can be achieved by a statin of proven clinical safety and chimeric human-mouse antibodies, agents now widely used and known to be of low immunogenicity in human hosts.

  8. Annual Surveillance Summary: Escherichia coli (E. coli) Infections in the Military Health System (MHS), 2015

    Science.gov (United States)

    2017-03-01

    Annual Surveillance Summary: Escherichia coli ( E . coli ) Infections in the Military Health System (MHS...or position of the Department of the Navy, Department of Defense, nor the U.S. Government. i i E . coli in the MHS: Annual Summary 2015 Prepared...March 2017 EpiData Center Department NMCPHC-EDC-TR-187-2017 ii ii E . coli in the MHS: Annual Summary 2015 Prepared March 2017 EpiData

  9. Chromosomal features of Escherichia coli serotype O2:K2, an avian pathogenic E. coli.

    Science.gov (United States)

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

    2017-01-01

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

  10. Hemolytic porcine intestinal Escherichia coli without virulence-associated genes typical of intestinal pathogenic E. coli.

    Science.gov (United States)

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

    2011-12-01

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

  11. Enteroaggregative Escherichia coli in Daycare

    DEFF Research Database (Denmark)

    Hebbelstrup Jensen, Betina; Stensvold, Christen R.; Struve, Carsten

    2016-01-01

    Enteroaggregative Escherichia coli (EAEC) has been associated with persistent diarrhea, reduced growth acceleration, and failure to thrive in children living in developing countries and with childhood diarrhea in general in industrialized countries. The clinical implications of an EAEC carrier...... and answered a questionnaire regarding gastrointestinal symptoms and exposures. Exposures included foreign travel, consumption of antibiotics, and contact with a diseased animal. In the capital area of Denmark, a total of 179 children aged 0-6 years were followed in a cohort study, in the period between 2009...

  12. Studies on the antidiarrhoeal activity of Aegle marmelos unripe fruit: Validating its traditional usage

    Directory of Open Access Journals (Sweden)

    Antia Noshir

    2009-11-01

    Full Text Available Abstract Background Aegle marmelos (L. Correa has been widely used in indigenous systems of Indian medicine due to its various medicinal properties. However, despite its traditional usage as an anti-diarrhoeal there is limited information regarding its mode of action in infectious forms of diarrhoea. Hence, we evaluated the hot aqueous extract (decoction of dried unripe fruit pulp of A. marmelos for its antimicrobial activity and effect on various aspects of pathogenicity of infectious diarrhoea. Methods The decoction was assessed for its antibacterial, antigiardial and antirotaviral activities. The effect of the decoction on adherence of enteropathogenic Escherichia coli and invasion of enteroinvasive E. coli and Shigella flexneri to HEp-2 cells were assessed as a measure of its effect on colonization. The effect of the decoction on production of E. coli heat labile toxin (LT and cholera toxin (CT and their binding to ganglioside monosialic acid receptor (GM1 were assessed by GM1-enzyme linked immuno sorbent assay whereas its effect on production and action of E. coli heat stable toxin (ST was assessed by suckling mouse assay. Results The decoction showed cidal activity against Giardia and rotavirus whereas viability of none of the six bacterial strains tested was affected. It significantly reduced bacterial adherence to and invasion of HEp-2 cells. The extract also affected production of CT and binding of both LT and CT to GM1. However, it had no effect on ST. Conclusion The decoction of the unripe fruit pulp of A. marmelos, despite having limited antimicrobial activity, affected the bacterial colonization to gut epithelium and production and action of certain enterotoxins. These observations suggest the varied possible modes of action of A. marmelos in infectious forms of diarrhoea thereby validating its mention in the ancient Indian texts and continued use by local communities for the treatment of diarrhoeal diseases.

  13. LTB-R1: an alternative to swine mycoplasmal pneumoniae control LTB-R1: uma alternativa para o controle da pneumonia micoplásmica suína

    Directory of Open Access Journals (Sweden)

    Fabrício Rochedo Conceição

    2003-11-01

    Full Text Available Mycoplasmal pneumoniae is the main respiratory disease in swine. The most efficient way to control it is through the use of vaccines (bacterins, whose production cost is high. The objective of this work was to develop a new alternative for controlling Swine Mycoplasmal Pneumoniae, based on a recombinant subunit vaccine containing the R1 region of P97 adhesin of Mycoplasma hyopneumoniae fused to the B subunit of the heat-labile enterotoxin of Escherichia coli (rLTB-R1. In this work we report the amplification of the genes, genetic fusion between LTB and R1 coding sequences, cloning, construction of the expression vector, as well as expression and purification of rLTB-R1 in E. coli.A Pneumonia Micoplásmica é a doença respiratória mais importante dos suínos. A forma mais eficaz de controlá-la é mediante a utilização de vacinas (bacterinas, cujo custo de produção é elevado. Uma nova alternativa para o controle desta doença, baseada em uma vacina de subunidade recombinante contendo a região R1 da adesina P97 de Mycoplasma hyopneumoniae fusionada a subunidade B da enterotoxina termolábel de Escherichia coli (rLTB-R1, foi o alvo deste trabalho. Nele abordou-se a amplificação dos genes, a fusão genética entre as seqüências codificadoras para LTB e R1, a clonagem, a construção do vetor de expressão, assim como a expressão em E. coli e purificação da rLTBR1.

  14. Peptidoglycan Hydrolases of Escherichia coli

    Science.gov (United States)

    van Heijenoort, Jean

    2011-01-01

    Summary: The review summarizes the abundant information on the 35 identified peptidoglycan (PG) hydrolases of Escherichia coli classified into 12 distinct families, including mainly glycosidases, peptidases, and amidases. An attempt is also made to critically assess their functions in PG maturation, turnover, elongation, septation, and recycling as well as in cell autolysis. There is at least one hydrolytic activity for each bond linking PG components, and most hydrolase genes were identified. Few hydrolases appear to be individually essential. The crystal structures and reaction mechanisms of certain hydrolases having defined functions were investigated. However, our knowledge of the biochemical properties of most hydrolases still remains fragmentary, and that of their cellular functions remains elusive. Owing to redundancy, PG hydrolases far outnumber the enzymes of PG biosynthesis. The presence of the two sets of enzymes acting on the PG bonds raises the question of their functional correlations. It is difficult to understand why E. coli keeps such a large set of PG hydrolases. The subtle differences in substrate specificities between the isoenzymes of each family certainly reflect a variety of as-yet-unidentified physiological functions. Their study will be a far more difficult challenge than that of the steps of the PG biosynthesis pathway. PMID:22126997

  15. Third International E. coli genome meeting

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1994-12-31

    Proceedings of the Third E. Coli Genome Meeting are provided. Presentations were divided into sessions entitled (1) Large Scale Sequencing, Sequence Analysis; (2) Databases; (3) Sequence Analysis; (4) Sequence Divergence in E. coli Strains; (5) Repeated Sequences and Regulatory Motifs; (6) Mutations, Rearrangements and Stress Responses; and (7) Origins of New Genes. The document provides a collection of abstracts of oral and poster presentations.

  16. Escherichia Coli Removal from Water Using Electrophotocatalytic ...

    African Journals Online (AJOL)

    Michael Horsfall

    inactivation of bacterial microorganisms in areas with low ... disinfection of water contaminated with fecal indicators such as E. coli ... media, brain heart infusion, sodium chloride, sodium hydroxide ... furnace at temperature 105 and 320°C f0r 60 min. For 2- and .... charge of E. coli logarithmic growth phase might affect the ...

  17. Antimicrobial resistance among commensal Escherichia coli from ...

    African Journals Online (AJOL)

    Commensal bacteria contribute to the distribution and persistence of antimicrobial resistance in the environment. This study monitored antimicrobial resistance in commensal Escherichia coli from the faeces of on-farm and slaughter cattle and beef. A total of 342 (89.5%) E. coli isolates were obtained from 382 samples.

  18. Characterization of Escherichia coli Phylogenetic Groups ...

    African Journals Online (AJOL)

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

  19. Biochemical and serological characterization of Escherichia coli ...

    African Journals Online (AJOL)

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

  20. PATHOGENIC POTENTIALS OF ESCHERICHIA COLI ISOLATED ...

    African Journals Online (AJOL)

    Electrolyte and haematological parameters in rabbits infected with pathogenic isolates of Escherichia coli from rural water supplies in Rivers State, Nigeria, where monitored. Rabbits were orally infected with suspension containing 3x107 cfu /ml of Escherichia coli to induce diarrhoea, and the electrolyte (sodium, potassium ...

  1. Fosfomycin Resistance in Escherichia coli, Pennsylvania, USA.

    Science.gov (United States)

    Alrowais, Hind; McElheny, Christi L; Spychala, Caressa N; Sastry, Sangeeta; Guo, Qinglan; Butt, Adeel A; Doi, Yohei

    2015-11-01

    Fosfomycin resistance in Escherichia coli is rare in the United States. An extended-spectrum β-lactamase-producing E. coli clinical strain identified in Pennsylvania, USA, showed high-level fosfomycin resistance caused by the fosA3 gene. The IncFII plasmid carrying this gene had a structure similar to those found in China, where fosfomycin resistance is commonly described.

  2. Strategies for Protein Overproduction in Escherichia coli.

    Science.gov (United States)

    Mott, John E.

    1984-01-01

    Examines heterologous expression in Escherichia coli and the role of regulatory sequences which control gene expression at transcription resulting in abundant production of messenger RNA and regulatory sequences in mRNA which promote efficient translation. Also examines the role of E. coli cells in stabilizing mRNA and protein that is…

  3. Escherichia coli survival in waters: Temperature dependence

    Science.gov (United States)

    Knowing the survival rates of water-borne Escherichia coli is important in evaluating microbial contamination and making appropriate management decisions. E. coli survival rates are dependent on temperature, a dependency that is routinely expressed using an analogue of the Q10 mo...

  4. Comparison of 61 Sequenced Escherichia coli Genomes

    DEFF Research Database (Denmark)

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

    2010-01-01

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

  5. Antimicrobial resistance among commensal Escherichia coli from ...

    African Journals Online (AJOL)

    user1

    2012-07-19

    Jul 19, 2012 ... Commensal bacteria contribute to the distribution and persistence of antimicrobial resistance in the environment. This study monitored antimicrobial resistance in commensal Escherichia coli from the faeces of on-farm and slaughter cattle and beef. A total of 342 (89.5%) E. coli isolates were obtained.

  6. Fimbrial adhesins from extraintestinal Escherichia coli

    DEFF Research Database (Denmark)

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

    2010-01-01

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

  7. lactamase in clinical isolates of Escherichia coli

    African Journals Online (AJOL)

    Jane

    2011-08-22

    Aug 22, 2011 ... The beta lactamase enzyme producing E. coli, resistant to β-lactam antibiotics, created many problems ... Key words: Escherichia coli, β-lactamase enzymes, TEM-type extended spectrum ... difficulties in treatment using antibiotics that are currently ... and chloramphenicol (30 µg) (Mast Diagnostics Ltd., UK).

  8. Detection of target staphylococcal enterotoxin B antigen in orange juice and popular carbonated beverages using antibody-dependent antigen-capture assays.

    Science.gov (United States)

    Principato, MaryAnn; Njoroge, Joyce M; Perlloni, Andrei; O' Donnell, Michael; Boyle, Thomas; Jones, Robert L

    2010-10-01

    There is a critical need for qualitative and quantitative methodologies that provide the rapid and accurate detection of food contaminants in complex food matrices. However, the sensitivity of the assay can be affected when antigen-capture is applied to certain foods or beverages that are extremely acidic. This study was undertaken to assess the effects of orange juice and popular carbonated soft drink upon the fidelity of antibody-based antigen-capture assays and to develop simple approaches that could rescue assay performance without the introduction of additional or extensive extraction procedures. We examined the effects of orange juice and a variety of popular carbonated soft drink beverages upon a quantitative Interleukin-2 (IL-2) enzyme-linked immunosorbent assay (ELISA) assay system and a lateral flow device (LFD) adapted for the detection of staphylococcal enterotoxin B (SEB) in foods. Alterations in the performance and sensitivity of the assay were directly attributable to the food matrix, and alterations in pH were especially critical. The results demonstrate that approaches such as an alteration of pH and the use of milk as a blocking agent, either singly or in combination, will partially rescue ELISA performance. The same approaches permit lateral flow to efficiently detect antigen. Practical Application: The authors present ways to rescue an ELISA assay compromised by acidity in beverages and show that either the alteration of pH, or the use of milk as a blocking agent are not always capable of restoring the assay to its intended efficiency. However, the same methods, when employed with lateral flow technology, are rapid and extremely successful.

  9. The immunogenic SigA enterotoxin of Shigella flexneri 2a binds to HEp-2 cells and induces fodrin redistribution in intoxicated epithelial cells.

    Directory of Open Access Journals (Sweden)

    Keith Al-Hasani

    Full Text Available BACKGROUND: We have previously shown that the enterotoxin SigA which resides on the she pathogenicity island (PAI of S. flexneri 2a is an autonomously secreted serine protease capable of degrading casein. We have also demonstrated that SigA is cytopathic for HEp-2 cells and plays a role in the intestinal fluid accumulation associated with S. flexneri infections. METHODS/PRINCIPAL FINDINGS: In this work we show that SigA binds specifically to HEp-2 cells and degrades recombinant human alphaII spectrin (alpha-fodrin in vitro, suggesting that the cytotoxic and enterotoxic effects mediated by SigA are likely associated with the degradation of epithelial fodrin. Consistent with our data, this study also demonstrates that SigA cleaves intracellular fodrin in situ, causing its redistribution within cells. These results strongly implicate SigA in altering the cytoskeleton during the pathogenesis of shigellosis. On the basis of these findings, cleavage of fodrin is a novel mechanism of cellular intoxication for a Shigella toxin. Furthermore, information regarding immunogenicity to SigA in infected patients is lacking. We studied the immune response of SigA from day 28 post-challenge serum of one volunteer from S. flexneri 2a challenge studies. Our results demonstrate that SigA is immunogenic following infection with S. flexneri 2a. CONCLUSIONS: This work shows that SigA binds to epithelial HEp-2 cells as well as being able to induce fodrin degradation in vitro and in situ, further extending its documented role in the pathogenesis of Shigella infections.

  10. Staphylococcal enterotoxin-like X (SElX is a unique superantigen with functional features of two major families of staphylococcal virulence factors.

    Directory of Open Access Journals (Sweden)

    Ries J Langley

    2017-09-01

    Full Text Available Staphylococcus aureus is an opportunistic pathogen that produces many virulence factors. Two major families of which are the staphylococcal superantigens (SAgs and the Staphylococcal Superantigen-Like (SSL exoproteins. The former are immunomodulatory toxins that induce a Vβ-specific activation of T cells, while the latter are immune evasion molecules that interfere with a wide range of innate immune defences. The superantigenic properties of Staphylococcal enterotoxin-like X (SElX have recently been established. We now reveal that SElX also possesses functional characteristics of the SSLs. A region of SElX displays high homology to the sialyl-lactosamine (sLacNac-specific binding site present in a sub-family of SSLs. By analysing the interaction of SElX with sLacNac-containing glycans we show that SElX has an equivalent specificity and host cell binding range to the SSLs. Mutation of key amino acids in this conserved region affects the ability of SElX to bind to cells of myeloid origin and significantly reduces its ability to protect S. aureus from destruction in a whole blood killing (WBK assay. Like the SSLs, SElX is up-regulated early during infection and is under the control of the S. aureus exotoxin expression (Sae two component gene regulatory system. Additionally, the structure of SElX in complex with the sLacNac-containing tetrasaccharide sialyl Lewis X (sLeX reveals that SElX is a unique single-domain SAg. In summary, SElX is an 'SSL-like' SAg.

  11. Isolation of a new ssDNA aptamer against staphylococcal enterotoxin B based on CNBr-activated sepharose-4B affinity chromatography.

    Science.gov (United States)

    Hedayati Ch, Mojtaba; Amani, Jafar; Sedighian, Hamid; Amin, Mohsen; Salimian, Jafar; Halabian, Raheleh; Imani Fooladi, Abbas Ali

    2016-09-01

    Staphylococcus aureus are potent human pathogens possessing arsenal of virulence factors. Staphylococcal food poisoning (SFP) and respiratory infections mediated by staphylococcal enterotoxin B (SEB) are common clinical manifestations. Many diagnostic techniques are based on serological detection and quantification of SEB in different food and clinical samples. Aptamers are known as new therapeutic and detection tools which are available in different ssDNA, dsDNA and protein structures. In this study, we used a new set of ssDNA aptamers against SEB. The methods used included preparation of a dsDNA library using standard SEB protein as the target analyte, affinity chromatography matrix in microfuge tubes, SELEX procedures to isolate specific ssDNA-aptamer as an affinity ligand, aptamer purification using ethanol precipitation method, affinity binding assay using ELISA, aptamer cloning and specificity test. Among 12 readable sequences, three of them were selected as the most appropriate aptamer because of their affinity and specificity to SEB. This study presents a new set of ssDNA aptamer with favorable selectivity to SEB through 12 rounds of SELEX. Selected aptamers were used to detect SEB in infected serum samples. Results showed that SEB c1 aptamer (2 µg SEB/100 nM aptamer) had favorable specificity to SEB (kd  = 2.3 × 10(-11) ). In conclusion, aptamers can be considered as useful tools for detecting and evaluating SEB. The results showed that affinity chromatography was an affordable assay with acceptable accuracy to isolate sensitive and selective novel aptamers. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  12. Effect of bile on growth, peritoneal absorption, and blood clearance of Escherichia coli in E coli peritonitis

    International Nuclear Information System (INIS)

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

    1991-01-01

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

  13. Infectious endocarditis caused by Escherichia coli

    DEFF Research Database (Denmark)

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

    2011-01-01

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

  14. Survival of pathogenic Escherichia coli on basil, lettuce, and spinach

    Science.gov (United States)

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

  15. 21 CFR 866.3255 - Escherichia coli serological reagents.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Escherichia coli serological reagents. 866.3255... coli serological reagents. (a) Identification. Escherichia coli serological reagents are devices that consist of antigens and antisera used in serological tests to identify Escherichia coli from cultured...

  16. A scoping study on the prevalence of Escherichia coli and ...

    African Journals Online (AJOL)

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

  17. 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

  18. (ESBL) producing Escherichia coli and Klebsiella pneumoniae

    African Journals Online (AJOL)

    use

    2011-11-21

    Nov 21, 2011 ... the most common serious bacterial infections in infants ... UTI is a common cause of morbidity .... of ESBL and non-ESBL producing Escherichia coli and Klebsiella pneumonia. ... in hospital and community acquired infections.

  19. FTIR nanobiosensors for Escherichia coli detection

    Directory of Open Access Journals (Sweden)

    Stefania Mura

    2012-07-01

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

  20. Escherichia coli pyomyositis in an immunocompromised host.

    Science.gov (United States)

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

    2011-08-01

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

  1. Characterization of Escherichia coli Phylogenetic Groups ...

    African Journals Online (AJOL)

    tract infection (UTI), bacteremia, pneumonia, soft-tissue infection, and ... Keywords: Drug resistance, Escherichia coli, Extraintestinal infections, Polymerase chain reaction, .... gynecology, 12 from orthopedics and 5 from pediatrics units.

  2. Infectious endocarditis caused by Escherichia coli

    DEFF Research Database (Denmark)

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

    2011-01-01

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

  3. Synergistic effects in mixed Escherichia coli biofilms

    DEFF Research Database (Denmark)

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

    2006-01-01

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

  4. Experimental induced avian E. coli salpingitis

    DEFF Research Database (Denmark)

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

    2016-01-01

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

  5. ECMDB: The E. coli Metabolome Database

    OpenAIRE

    Guo, An Chi; Jewison, Timothy; Wilson, Michael; Liu, Yifeng; Knox, Craig; Djoumbou, Yannick; Lo, Patrick; Mandal, Rupasri; Krishnamurthy, Ram; Wishart, David S.

    2012-01-01

    The Escherichia coli Metabolome Database (ECMDB, http://www.ecmdb.ca) is a comprehensively annotated metabolomic database containing detailed information about the metabolome of E. coli (K-12). Modelled closely on the Human and Yeast Metabolome Databases, the ECMDB contains >2600 metabolites with links to ?1500 different genes and proteins, including enzymes and transporters. The information in the ECMDB has been collected from dozens of textbooks, journal articles and electronic databases. E...

  6. Newer insights into the mechanism of action of Psidium guajava L. leaves in infectious diarrhoea.

    Science.gov (United States)

    Birdi, Tannaz; Daswani, Poonam; Brijesh, S; Tetali, Pundarikakshudu; Natu, Arvind; Antia, Noshir

    2010-06-28

    Psidium guajava L., Myrtaceae, is used widely in traditional medicine for the treatment of diarrhoea, dysentery, gastroenteritis, stomachaches, and indigestion. However, the effect of the leaf extract of P. guajava on the pathogenesis of infectious diarrhoea has not been studied. The present study evaluates the effect of a hot aqueous extract (decoction) of dried leaves of P. guajava on parameters associated with pathogenicity of infectious diarrhoea. The aim was to understand its possible mechanism(s) of action in controlling infectious diarrhoea and compare it with quercetin, one of the most reported active constituents of P. guajava with antidiarrhoeal activity. The crude decoction and quercetin were studied for their antibacterial activity and effect on virulence features of common diarrhoeal pathogens viz. colonization of epithelial cells and production and action of enterotoxins. Colonization as measured by adherence of enteropathogenic Escherichia coli (EPEC) and invasion of enteroinvasive E. coli (EIEC) and Shigella flexneri was assessed using HEp-2 cell line. The production of E. coli heat labile toxin (LT) and cholera toxin (CT) and their binding to ganglioside monosialic acid (GM1) were studied by GM1-ELISA whereas the production and action of E. coli heat stable toxin (ST) was assessed by suckling mouse assay. The decoction of P. guajava showed antibacterial activity towards S. flexneri and Vibrio cholerae. It decreased production of both LT and CT and their binding to GM1. However, it had no effect on production and action of ST. The decoction also inhibited the adherence of EPEC and invasion by both EIEC and S. flexneri to HEp-2 cells. Quercetin, on the other hand, had no antibacterial activity at the concentrations used nor did it affect any of the enterotoxins. Although it did not affect adherence of EPEC, it inhibited the invasion of both EIEC and S. flexneri to HEp-2 cells. Collectively, the results indicate that the decoction of P. guajava leaves

  7. Newer insights into the mechanism of action of Psidium guajava L. leaves in infectious diarrhoea

    Directory of Open Access Journals (Sweden)

    Natu Arvind

    2010-06-01

    Full Text Available Abstract Background Psidium guajava L., Myrtaceae, is used widely in traditional medicine for the treatment of diarrhoea, dysentery, gastroenteritis, stomachaches, and indigestion. However, the effect of the leaf extract of P. guajava on the pathogenesis of infectious diarrhoea has not been studied. The present study evaluates the effect of a hot aqueous extract (decoction of dried leaves of P. guajava on parameters associated with pathogenicity of infectious diarrhoea. The aim was to understand its possible mechanism(s of action in controlling infectious diarrhoea and compare it with quercetin, one of the most reported active constituents of P. guajava with antidiarrhoeal activity. Methods The crude decoction and quercetin were studied for their antibacterial activity and effect on virulence features of common diarrhoeal pathogens viz. colonization of epithelial cells and production and action of enterotoxins. Colonization as measured by adherence of enteropathogenic Escherichia coli (EPEC and invasion of enteroinvasive E. coli (EIEC and Shigella flexneri was assessed using HEp-2 cell line. The production of E. coli heat labile toxin (LT and cholera toxin (CT and their binding to ganglioside monosialic acid (GM1 were studied by GM1-ELISA whereas the production and action of E. coli heat stable toxin (ST was assessed by suckling mouse assay. Results The decoction of P. guajava showed antibacterial activity towards S. flexneri and Vibrio cholerae. It decreased production of both LT and CT and their binding to GM1. However, it had no effect on production and action of ST. The decoction also inhibited the adherence of EPEC and invasion by both EIEC and S. flexneri to HEp-2 cells. Quercetin, on the other hand, had no antibacterial activity at the concentrations used nor did it affect any of the enterotoxins. Although it did not affect adherence of EPEC, it inhibited the invasion of both EIEC and S. flexneri to HEp-2 cells. Conclusion Collectively

  8. Up-regulation of granzyme B and perforin by staphylococcal enterotoxin C2 mutant induces enhanced cytotoxicity in Hepa1–6 cells

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Guojun [Institute of Applied Ecology, Chinese Academy of Sciences, No.72 Wenhua Road Shenhe Dis., Shenyang, Liaoning (China); University of Chinese Academy of Sciences, Beijing (China); Xu, Mingkai, E-mail: mkxu@iae.ac.cn [Institute of Applied Ecology, Chinese Academy of Sciences, No.72 Wenhua Road Shenhe Dis., Shenyang, Liaoning (China); Zhang, Huiwen [Institute of Applied Ecology, Chinese Academy of Sciences, No.72 Wenhua Road Shenhe Dis., Shenyang, Liaoning (China); Song, Yubo [Institute of Applied Ecology, Chinese Academy of Sciences, No.72 Wenhua Road Shenhe Dis., Shenyang, Liaoning (China); University of Chinese Academy of Sciences, Beijing (China); Wang, Jian; Zhang, Chenggang [Institute of Applied Ecology, Chinese Academy of Sciences, No.72 Wenhua Road Shenhe Dis., Shenyang, Liaoning (China)

    2016-12-15

    Staphylococcal enterotoxin C2 (SEC2), a member of bacterial superantigen, is one of the most potent known activators of T lymphocytes. With this property, SEC2 has already been used in clinic as a tumor immunotherapy agent in China. To increase the antitumor activity, a SEC2 mutant named ST-4 (GKVTG102-106WWH) with amino acid substitutions in T cell receptor (TCR)-binding domain was generated by site-directed mutagenesis, and the molecular mechanism of the enhanced antitumor activity was investigated. Results showed that ST-4 could activate much more Vβ 8.2 and 8.3 T cells and NK cells compared with SEC2, and exhibited significantly enhanced immunocyte stimulation and antitumor activity in vitro. The synthetic peptide sequencing the residues of mutant TCR-binding domain could competitively inhibit the immunocyte stimulation activity of ST-4. Most importantly, ST-4 up-regulated granzyme B and perforin at both mRNA and protein levels. We also found that expression of proapoptotic proteins cytochrome c, BAX and activation of caspase-3, 9 was up-regulated, and antiapoptotic protein Bcl-xL was down-regulated in the treatment with either ST-4 or SEC2. When granzyme B inhibitor or perforin inhibitor is presented, tumor cell viability was significantly rescued. Taken together, we demonstrate that increased ST-4-TCR recognition contributed to massive T cells and NK cells activation. These activated cells released up-regulated granzyme B and perforin, which induced the enhanced tumor cells apoptosis by mitochondrial apoptotic pathway, and ultimately led to enhanced tumor cell growth inhibition. ST-4 may be a promising candidate for antitumor clinic usage in future. - Highlights: • We obtained a SEC2 mutant ST-4 with enhanced superantigen and antitumor activity. • Increased ST-4-TCR recognition contributed to massive T cells and NK cells activation. • Up-regulated GzmB and PRF1 in T cell by ST-4 induced enhanced tumor cells apoptosis. • Enhanced tumor cell apoptosis

  9. Natural indoles, indole-3-carbinol and 3,3′-diindolymethane, inhibit T cell activation by staphylococcal enterotoxin B through epigenetic regulation involving HDAC expression

    International Nuclear Information System (INIS)

    Busbee, Philip B.; Nagarkatti, Mitzi; Nagarkatti, Prakash S.

    2014-01-01

    Staphylococcal enterotoxin B (SEB) is a potent exotoxin produced by the Staphylococcus aureus. This toxin is classified as a superantigen because of its ability to directly bind with MHC-II class molecules followed by activation of a large proportion of T cells bearing specific Vβ-T cell receptors. Commonly associated with classic food poisoning, SEB has also been shown to induce toxic shock syndrome, and is also considered to be a potential biological warfare agent because it is easily aerosolized. In the present study, we assessed the ability of indole-3-carbinol (I3C) and one of its byproducts, 3,3′-diindolylmethane (DIM), found in cruciferous vegetables, to counteract the effects of SEB-induced activation of T cells in mice. Both I3C and DIM were found to decrease the activation, proliferation, and cytokine production by SEB-activated Vβ8 + T cells in vitro and in vivo. Interestingly, inhibitors of histone deacetylase class I (HDAC-I), but not class II (HDAC-II), showed significant decrease in SEB-induced T cell activation and cytokine production, thereby suggesting that epigenetic modulation plays a critical role in the regulation of SEB-induced inflammation. In addition, I3C and DIM caused a decrease in HDAC-I but not HDAC-II in SEB-activated T cells, thereby suggesting that I3C and DIM may inhibit SEB-mediated T cell activation by acting as HDAC-I inhibitors. These studies not only suggest for the first time that plant-derived indoles are potent suppressors of SEB-induced T cell activation and cytokine storm but also that they may mediate these effects by acting as HDAC inhibitors. - Highlights: • I3C and DIM reduce SEB-induced T cell activation and inflammatory cytokines. • Inhibiting class I HDACs reduces T cell activation and inflammatory cytokines. • Inhibiting class II HDACs increases T cell activation and inflammatory cytokines. • I3C and DIM selectively reduce mRNA expression of class I HDACs. • Novel use and mechanism to counteract SEB

  10. Natural indoles, indole-3-carbinol and 3,3′-diindolymethane, inhibit T cell activation by staphylococcal enterotoxin B through epigenetic regulation involving HDAC expression

    Energy Technology Data Exchange (ETDEWEB)

    Busbee, Philip B.; Nagarkatti, Mitzi; Nagarkatti, Prakash S., E-mail: prakash@mailbox.sc.edu

    2014-01-01

    Staphylococcal enterotoxin B (SEB) is a potent exotoxin produced by the Staphylococcus aureus. This toxin is classified as a superantigen because of its ability to directly bind with MHC-II class molecules followed by activation of a large proportion of T cells bearing specific Vβ-T cell receptors. Commonly associated with classic food poisoning, SEB has also been shown to induce toxic shock syndrome, and is also considered to be a potential biological warfare agent because it is easily aerosolized. In the present study, we assessed the ability of indole-3-carbinol (I3C) and one of its byproducts, 3,3′-diindolylmethane (DIM), found in cruciferous vegetables, to counteract the effects of SEB-induced activation of T cells in mice. Both I3C and DIM were found to decrease the activation, proliferation, and cytokine production by SEB-activated Vβ8{sup +} T cells in vitro and in vivo. Interestingly, inhibitors of histone deacetylase class I (HDAC-I), but not class II (HDAC-II), showed significant decrease in SEB-induced T cell activation and cytokine production, thereby suggesting that epigenetic modulation plays a critical role in the regulation of SEB-induced inflammation. In addition, I3C and DIM caused a decrease in HDAC-I but not HDAC-II in SEB-activated T cells, thereby suggesting that I3C and DIM may inhibit SEB-mediated T cell activation by acting as HDAC-I inhibitors. These studies not only suggest for the first time that plant-derived indoles are potent suppressors of SEB-induced T cell activation and cytokine storm but also that they may mediate these effects by acting as HDAC inhibitors. - Highlights: • I3C and DIM reduce SEB-induced T cell activation and inflammatory cytokines. • Inhibiting class I HDACs reduces T cell activation and inflammatory cytokines. • Inhibiting class II HDACs increases T cell activation and inflammatory cytokines. • I3C and DIM selectively reduce mRNA expression of class I HDACs. • Novel use and mechanism to counteract

  11. Staphylococcal Entertotoxins of the Enterotoxin Gene Cluster (egcSEs Induce Nitrous Oxide- and Cytokine Dependent Tumor Cell Apoptosis in a Broad Panel of Human Tumor Cells

    Directory of Open Access Journals (Sweden)

    David eTerman

    2013-08-01

    Full Text Available The egcSEs comprise five genetically linked staphylococcal enterotoxins, SEG, SEI, SElM, SElN and SElO and two pseudotoxins which constitute an operon present in up to 80% of Staphylococcus aureus isolates. A preparation containing theses proteins was recently used to treat advanced lung cancer with pleural effusion. We investigated the hypothesis that egcSEs induce nitrous oxide (NO and associated cytokine production and that these agents may be involved in tumoricidal effects against a broad panel of clinically relevant human tumor cells. Preliminary studies showed that egcSEs and SEA activated T cells (range: 11-25% in a concentration dependent manner. Peripheral blood mononuclear cells (PBMCs stimulated with equimolar quantities of egcSEs expressed NO synthase and generated robust levels of nitrite (range: 200-250 µM, a breakdown product of NO; this reaction was inhibited by NG-monomethyl-L-arginine (L-NMMA (0.3 mM, an NO synthase antagonist. Cell free supernatants (CSFs of all egcSE-stimulated PBMCs were also equally effective in inducing concentration dependent tumor cell apoptosis in a broad panel of human tumor cells. The latter effect was due in part to the generation of NO and TNF-α since it was significantly abolished by L-NMMA, anti-TNF-α antibodies respectively and a combination thereof. A hierarchy of tumor cell sensitivity to these CFSs was as follows: lung carcinoma>osteogenic sarcoma>melanoma>breast carcinoma>neuroblastoma. Notably, SEG induced robust activation of NO/TNFα-dependent tumor cell apoptosis comparable to the other egcSEs and SEA despite TNF-α and IFN-γ levels that were 2 and 8 fold lower respectively than the other egcSEs and SEA. Thus, egcSEs produced by S. aureus induce NO synthase and the increased NO formation together with TNF-α appear to contribute to egcSE-mediated apoptosis against a broad panel of human tumor cells.

  12. Identification and Prevalence of Escherichia coli and Escherichia coli O157: H7 in Foods

    Directory of Open Access Journals (Sweden)

    Ancuta Mihaela Rotar

    2013-11-01

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

  13. 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...

  14. Cloning and Expression of Fusion Genes of Domain A-1 Protective Antigen of Bacillus Anthracis and Shigella Enterotoxin B Subunit (Stxb In E. Coil

    Directory of Open Access Journals (Sweden)

    AH ahmadi

    2015-02-01

    Conclusion: The findings of the current study revealed that this antigen can be raised as an anti-cancer and recombinant vaccine candidate against types of Shigella, Escherichia coli and Bacillus anthracis which can be due to such factors as identification of antigen(PA by antibody PA20, its apoptosis induction properties, property of immunogenicity, adjuvant and delivery of STxB protein and high expression levels of Gb3 in human cancer cells.

  15. Photoinactivation of mcr-1 positive Escherichia coli

    Science.gov (United States)

    Caires, C. S. A.; Leal, C. R. B.; Rodrigues, A. C. S.; Lima, A. R.; Silva, C. M.; Ramos, C. A. N.; Chang, M. R.; Arruda, E. J.; Oliveira, S. L.; Nascimento, V. A.; Caires, A. R. L.

    2018-01-01

    The emergence of plasmid-mediated colistin resistance in Enterobacteriaceae, mostly in Escherichia coli due to the mcr-1 gene, has revealed the need to develop alternative approaches in treating mcr-1 positive bacterial infections. This is because colistin is a broad-spectrum antibiotic and one of the ‘last-resort’ antibiotics for multidrug resistant bacteria. The present study evaluated for the first time, to the best of our knowledge, the efficacy of photoinactivation processes to kill a known mcr-1 positive E. coli strain. Eosin methylene-blue (EMB) was investigated as a photoantimicrobial agent for inhibiting the growth of a mcr-1 positive E. coli strain obtained from a patient with a diabetic foot infection. The photoantimicrobial activity of EMB was also tested in a non-multidrug resistant E. coli strain. The photoinactivation process was tested using light doses in the 30-45 J cm-2 range provided by a LED device emitting at 625 nm. Our findings demonstrate that a mcr-1 positive E. coli strain is susceptible to photoinactivation. The results show that the EMB was successfully photoactivated, regardless of the bacterial multidrug resistance; inactivating the bacterial growth by oxidizing the cells in accordance with the generation of the oxygen reactive species. Our results suggest that bacterial photoinactivation is an alternative and effective approach to kill mcr-1 positive bacteria.

  16. Profiling of Escherichia coli Chromosome database.

    Science.gov (United States)

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

    2008-01-01

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

  17. Current pathogenic Escherichia coli foodborne outbreak cases and therapy development.

    Science.gov (United States)

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

    2017-08-01

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

  18. Action of sodium deoxycholate on Escherichia coli

    International Nuclear Information System (INIS)

    D'Mello, A.; Yotis, W.W.

    1987-01-01

    Sodium deoxycholate is used in a number of bacteriological media for the isolation and classification of gram-negative bacteria from food and the environment. Initial experiments to study the effect of deoxycholate on the growth parameters of Escherichia coli showed an increase in the lag time constant and generation time and a decrease in the growth rate constant total cell yield of this microorganisms. Cell fractionation studies indicated that sodium deoxycholate at levels used in bacteriological media interferes with the incorporation of [U- 14 C]glucose into the cold-trichloroacetic acid-soluble, ethanol-soluble, and trypsin-soluble cellular fractions of E. coli. Finally, sodium deoxycholate interfered with the flagellation and motility of Proteus mirabilis and E. coli. It would appear then that further improvement of the deoxycholate medium may be in order

  19. Prodigiosin - A Multifaceted Escherichia coli Antimicrobial Agent.

    Directory of Open Access Journals (Sweden)

    Tjaša Danevčič

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

  20. Deuterium incorporation into Escherichia-coli proteins

    DEFF Research Database (Denmark)

    Lederer, H.; May, R. P.; Kjems, Jørgen

    1986-01-01

    Neutron small-angle scattering studies of single protein subunits in a protein-DNA complex require the adjustment of the neutron scattering-length densities of protein and DNA, which is attainable by specific deuteration of the protein. The neutron scattering densities of unlabelled DNA and DNA......-dependent RNA polymerase of Escherichia coli match when RNA polymerase is isolated from cells grown in a medium containing 46% D2O and unlabelled glucose as carbon source. Their contrasts vanish simultaneously in a dialysis buffer containing 65% D2O. An expression was evaluated which allows the calculation...... of the degree of deuteration and match point of any E. coli protein from the D2O content of the growth medium, taking the 2H incorporation into RNA polymerase amino acids to be representative for all amino acids in E. coli proteins. The small-angle scattering results, on which the calculation of the degree...

  1. Action of sodium deoxycholate on Escherichia coli

    Energy Technology Data Exchange (ETDEWEB)

    D' Mello, A.; Yotis, W.W.

    1987-08-01

    Sodium deoxycholate is used in a number of bacteriological media for the isolation and classification of gram-negative bacteria from food and the environment. Initial experiments to study the effect of deoxycholate on the growth parameters of Escherichia coli showed an increase in the lag time constant and generation time and a decrease in the growth rate constant total cell yield of this microorganisms. Cell fractionation studies indicated that sodium deoxycholate at levels used in bacteriological media interferes with the incorporation of (U-/sup 14/C)glucose into the cold-trichloroacetic acid-soluble, ethanol-soluble, and trypsin-soluble cellular fractions of E. coli. Finally, sodium deoxycholate interfered with the flagellation and motility of Proteus mirabilis and E. coli. It would appear then that further improvement of the deoxycholate medium may be in order.

  2. The yield of DNA double strand breaks determined after exclusion of those forming from heat-labile lesions predicts tumor cell radiosensitivity to killing.

    Science.gov (United States)

    Cheng, Yanlei; Li, Fanghua; Mladenov, Emil; Iliakis, George

    2015-09-01

    The radiosensitivity to killing of tumor cells and in-field normal tissue are key determinants of radiotherapy response. In vitro radiosensitivity of tumor- and normal-tissue-derived cells often predicts radiation response, but high determination cost in time and resources compromise utility as routine response-predictor. Efforts to use induction or repair of DNA double-strand-breaks (DSBs) as surrogate-predictors of cell radiosensitivity to killing have met with limited success. Here, we re-visit this issue encouraged by our recent observations that ionizing radiation (IR) induces not only promptly-forming DSBs (prDSBs), but also DSBs developing after irradiation from the conversion to breaks of thermally-labile sugar-lesions (tlDSBs). We employ pulsed-field gel-electrophoresis and flow-cytometry protocols to measure total DSBs (tDSB=prDSB+tlDSBs) and prDSBs, as well as γH2AX and parameters of chromatin structure. We report a fully unexpected and in many ways unprecedented correlation between yield of prDSBs and radiosensitivity to killing in a battery of ten tumor cell lines that is not matched by yields of tDSBs or γH2AX, and cannot be explained by simple parameters of chromatin structure. We propose the introduction of prDSBs-yield as a novel and powerful surrogate-predictor of cell radiosensitivity to killing with potential for clinical application. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  3. Production and evaluation of a recombinant chimeric vaccine against clostridium botulinum neurotoxin types C and D.

    Directory of Open Access Journals (Sweden)

    Luciana A F Gil

    Full Text Available Bovine botulism is a fatal disease that is caused by botulinum neurotoxins (BoNTs produced by Clostridium botulinum serotypes C and D and that causes great economic losses, with nearly 100% lethality during outbreaks. It has also been considered a potential source of human food-borne illness in many countries. Vaccination has been reported to be the most effective way to control bovine botulism. However, the commercially available toxoid-based vaccines are difficult and hazardous to produce. Neutralizing antibodies targeted against the C-terminal fragment of the BoNT heavy chain (HC are known to confer efficient protection against lethal doses of BoNTs. In this study, a novel recombinant chimera, consisting of Escherichia coli heat-labile enterotoxin B subunit (LTB, a strong adjuvant of the humoral immune response, fused to the HC of BoNT serotypes C and D, was produced in E. coli. Mice vaccinated with the chimera containing LTB and an equivalent molar ratio of the chimera without LTB plus aluminum hydroxide (Al(OH3 developed 2 IU/mL of antitoxins for both serotypes. Guinea pigs immunized with the recombinant chimera with LTB plus Al(OH3 developed a protective immune response against both BoNT/C (5 IU/mL and BoNT/D (10 IU/mL, as determined by a mouse neutralization bioassay with pooled sera. The results achieved with guinea pig sera fulfilled the requirements of commercial vaccines for prevention of botulism, as determined by the Brazilian Ministry of Agriculture, Livestock and Food, Supply. The presence of LTB was essential for the development of a strong humoral immune response, as it acted in synergism with Al(OH3. Thus, the vaccine described in this study is a strong candidate for the control of botulism in cattle.

  4. Melanosis coli in patients with colon cancer

    Directory of Open Access Journals (Sweden)

    Dorota Biernacka-Wawrzonek

    2016-12-01

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

  5. 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

  6. Vaginal Lactobacillus isolates inhibit uropathogenic Escherichia coli.

    OpenAIRE

    Atassi , Fabrice; Brassart , Dominique; Grob , Philipp; Graf , Federico; Servin , Alain ,

    2006-01-01

    The purpose of this study was to investigate the antibacterial activities of Lactobacillus jensenii KS119.1 and KS121.1, and Lactobacillus gasserii KS120.1 and KS124.3 strains isolated from the vaginal microflora of healthy women, against uropathogenic, diffusely adhering Afa/Dr Escherichia coli (Afa/Dr DAEC) strains IH11128 and 7372 involved in recurrent cystitis. We observed that some of the Lactobacillus isolates inhibited the growth and decreased the viability of E. coli IH11128 and 7372....

  7. Synthesis of avenanthramides using engineered Escherichia coli.

    Science.gov (United States)

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

    2018-03-22

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

  8. Epidemiology and clinical manifestations of enteroaggregative Escherichia coli

    DEFF Research Database (Denmark)

    Hebbelstrup Jensen, Betina; Olsen, Katharina E P; Struve, Carsten

    2014-01-01

    Enteroaggregative Escherichia coli (EAEC) represents a heterogeneous group of E. coli strains. The pathogenicity and clinical relevance of these bacteria are still controversial. In this review, we describe the clinical significance of EAEC regarding patterns of infection in humans, transmission...

  9. lactamases genes among0 Escherichia coli from patients with ...

    African Journals Online (AJOL)

    -lactamases (ESBLs) that mediate resistance to b-lactam drugs among Escherichia coli and other uropathogens have been reported worldwide. However, there is little information on the detection of ESBLs genes in E. coli from patients with ...

  10. Plasmid-Mediated Quinolone Resistance Genes in Escherichia coli ...

    African Journals Online (AJOL)

    Erah

    PMQR) genes and the prevalence of extended spectrum β-lactamase (ESBL) types in Escherichia coli clinical isolates. Methods: Sixty-one ESBL-producing urinary E. coli isolates were studied. An antibiotic susceptibility test was performed ...

  11. 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).

  12. Distribution of Diverse Escherichia coli between Cattle and Pasture

    OpenAIRE

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

    2017-01-01

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

  13. Lipocalin 2 is protective against E. coli pneumonia

    DEFF Research Database (Denmark)

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

    2010-01-01

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

  14. WGS accurately predicts antimicrobial resistance in Escherichia coli

    Science.gov (United States)

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

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

    African Journals Online (AJOL)

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

  16. Antimicrobial susceptibility patterns of E. coli from clinical sources in ...

    African Journals Online (AJOL)

    Background: Escherichia coli is the leading cause of urinary tract, ear, wound and other infections in humans. Increasing rates of antimicrobial resistance among E. coli is a growing concern worldwide. Objectives: The aim of this study was to determine the prevalence and antimicrobial susceptibility of E. coli from clinical ...

  17. 77 FR 9888 - Shiga Toxin-Producing Escherichia coli

    Science.gov (United States)

    2012-02-21

    ... Toxin-Producing Escherichia coli in Certain Raw Beef Products AGENCY: Food Safety and Inspection Service... toxin-producing Escherichia coli (STEC) serogroups (O26, O45, O103, O111, O121, and O145). This new date..., that are contaminated with Shiga toxin-producing Escherichia coli (STEC) O26, O45, O103, O111, O121...

  18. Gene encoding virulence markers among Escherichia coli isolates ...

    African Journals Online (AJOL)

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

  19. Isolation and genomic characterization of Escherichia coli O157:NM ...

    African Journals Online (AJOL)

    Human diseases caused by Escherichia coli O157:NM and E. coli O157:H7 strains have been reported throughout the world. In developed countries, serotype O157:H7 represents the major cause of human diseases; however, there have been increasing reports of non-O157 Shiga toxin (Stx)-producing E. coli strains ...

  20. Neonatal infections caused by Escherichia coli at the National ...

    African Journals Online (AJOL)

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

  1. neonatal infections caused by escherichia coli at the national

    African Journals Online (AJOL)

    boaz

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

  2. Prevalence, antimicrobial resistance and multiple-locus variable-number tandem-repeat analysis profiles of diarrheagenic Escherichia coli isolated from different retail foods.

    Science.gov (United States)

    Wang, Lili; Nakamura, Hiromi; Kage-Nakadai, Eriko; Hara-Kudo, Yukiko; Nishikawa, Yoshikazu

    2017-05-16

    Diarrheagenic E. coli (DEC) isolates were recovered from local retail markets and the Osaka Municipal Central Wholesale Market in Japan. Retail food samples were collected for analysis in Osaka Japan from 2005 to 2008 and consisted of 32 beef, 28 pork, 20 poultry, 136 fish, 66 fruits and vegetables and 51 ready-to-eat (RTE) food samples. A total of 82 DEC strains were recovered from 64 (19%) food samples with the highest prevalence in poultry (100%, 20/20), followed by pork (54%, 15/28), beef (28%, 9/32), fruits and vegetables (12%, 8/66), fish (6.6%, 9/136) and RTE foods (5.9%, 3/51). Most of the strains belonged to E. coli possessing the enteroaggregative E. coli (EAEC) heat-stable enterotoxin 1 (EAST1) gene (EAST1EC; n=62, P3 antimicrobial agents. Isolates resistant to >5 antimicrobials were only found in the meat samples, while isolates from the fruits and vegetables as well as RTE foods showed resistance to only 1 or 2 antimicrobial agents. Sixty one percent of EAST1EC, 56% of EPEC and all of the EAEC and ETEC were resistant to at least 1 antimicrobial agent. Multiple-locus variable-number tandem repeat analysis (MLVA) was used in this study for genotyping of DEC. The 82 isolates collected for this study showed 77 distinct MLVA profiles located among 3 branches. The Simpson's Index of Diversity (D) was 99.9% at its highest. The high diversity of these food strains would suggest their originating from a variety of sources and environments. In conclusion, retail food samples in Japan were contaminated with DEC; EAST1EC, a putative DEC, were detected at high rates in poultry, pork and beef. Isolates resistant to >3 antimicrobials were found only in raw meat and fish. Food animals may act as the reservoir for multi-resistant bacteria. Due to the finding that nearly 1/3 of EAST1EC strains were resistant to >3 antimicrobials, additional surveillance for EAST1EC should be initiated. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Ethanol production using engineered mutant E. coli

    Science.gov (United States)

    Ingram, Lonnie O.; Clark, David P.

    1991-01-01

    The subject invention concerns novel means and materials for producing ethanol as a fermentation product. Mutant E. coli are transformed with a gene coding for pyruvate decarboxylase activity. The resulting system is capable of producing relatively large amounts of ethanol from a variety of biomass sources.

  4. E. Coli: Preventing Outbreaks at Camp.

    Science.gov (United States)

    McKinney, Mary D.

    1996-01-01

    One strain of E. coli is not usually found in foods, but has been related to consumption of undercooked ground beef. Symptoms are stomach cramps and diarrhea, and 2-7% of infections lead to hemolytic uremic syndrome, which is life threatening. Camps can prevent outbreaks by avoiding uncooked meat on overnight campouts and requiring appropriate…

  5. Identifying New Small Proteins in Escherichia coli.

    Science.gov (United States)

    VanOrsdel, Caitlin E; Kelly, John P; Burke, Brittany N; Lein, Christina D; Oufiero, Christopher E; Sanchez, Joseph F; Wimmers, Larry E; Hearn, David J; Abuikhdair, Fatimeh J; Barnhart, Kathryn R; Duley, Michelle L; Ernst, Sarah E G; Kenerson, Briana A; Serafin, Aubrey J; Hemm, Matthew R

    2018-04-12

    The number of small proteins (SPs) encoded in the Escherichia coli genome is unknown, as current bioinformatics and biochemical techniques make short gene and small protein identification challenging. One method of small protein identification involves adding an epitope tag to the 3' end of a short open reading frame (sORF) on the chromosome, with synthesis confirmed by immunoblot assays. In this study, this strategy was used to identify new E. coli small proteins, tagging 80 sORFs in the E. coli genome, and assayed for protein synthesis. The selected sORFs represent diverse sequence characteristics, including degrees of sORF conservation, predicted transmembrane domains, sORF direction with respect to flanking genes, ribosome binding site (RBS) prediction, and ribosome profiling results. Of 80 sORFs, 36 resulted in encoded synthesized proteins-a 45% success rate. Modeling of detected versus non-detected small proteins analysis showed predictions based on RBS prediction, transcription data, and ribosome profiling had statistically-significant correlation with protein synthesis; however, there was no correlation between current sORF annotation and protein synthesis. These results suggest substantial numbers of small proteins remain undiscovered in E. coli, and existing bioinformatics techniques must continue to improve to facilitate identification. © 2018 The Authors. Proteomics Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim, Towson University.

  6. Engineering Escherichia coli for methanol conversion.

    Science.gov (United States)

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

    2015-03-01

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

  7. Optimization of plasmid electrotransformation into Escherichia coli ...

    African Journals Online (AJOL)

    In order to improve electroporation, optical density of bacteria, recovery time and electrical parameter (field strength and capacitance) were optimized using the Taguchi statistical method. ANOVA of obtained data indicated that the optimal conditions of electrotransformation of pET-28a (+) plasmid into Escherichia coli ...

  8. Transport proteins promoting Escherichia coli pathogenesis

    Science.gov (United States)

    Tang, Fengyi; Saier, Milton H.

    2014-01-01

    Escherichia coli is a genetically diverse species infecting hundreds of millions of people worldwide annually. We examined seven well-characterized E. coli pathogens causing urinary tract infections, gastroenteritis, pyelonephritis and haemorrhagic colitis. Their transport proteins were identified and compared with each other and a non-pathogenic E. coli K12 strain to identify transport proteins related to pathogenesis. Each pathogen possesses a unique set of protein secretion systems for export to the cell surface or for injecting effector proteins into host cells. Pathogens have increased numbers of iron siderophore receptors and ABC iron uptake transporters, but the numbers and types of low-affinity secondary iron carriers were uniform in all strains. The presence of outer membrane iron complex receptors and high-affinity ABC iron uptake systems correlated, suggesting co-evolution. Each pathovar encodes a different set of pore-forming toxins and virulence-related outer membrane proteins lacking in K12. Intracellular pathogens proved to have a characteristically distinctive set of nutrient uptake porters, different from those of extracellular pathogens. The results presented in this report provide information about transport systems relevant to various types of E. coli pathogenesis that can be exploited in future basic and applied studies. PMID:24747185

  9. Transport proteins promoting Escherichia coli pathogenesis.

    Science.gov (United States)

    Tang, Fengyi; Saier, Milton H

    2014-01-01

    Escherichia coli is a genetically diverse species infecting hundreds of millions of people worldwide annually. We examined seven well-characterized E. coli pathogens causing urinary tract infections, gastroenteritis, pyelonephritis and haemorrhagic colitis. Their transport proteins were identified and compared with each other and a non-pathogenic E. coli K12 strain to identify transport proteins related to pathogenesis. Each pathogen possesses a unique set of protein secretion systems for export to the cell surface or for injecting effector proteins into host cells. Pathogens have increased numbers of iron siderophore receptors and ABC iron uptake transporters, but the numbers and types of low-affinity secondary iron carriers were uniform in all strains. The presence of outer membrane iron complex receptors and high-affinity ABC iron uptake systems correlated, suggesting co-evolution. Each pathovar encodes a different set of pore-forming toxins and virulence-related outer membrane proteins lacking in K12. Intracellular pathogens proved to have a characteristically distinctive set of nutrient uptake porters, different from those of extracellular pathogens. The results presented in this report provide information about transport systems relevant to various types of E. coli pathogenesis that can be exploited in future basic and applied studies. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Isolation and molecular characterization of Campylobacter coli

    African Journals Online (AJOL)

    Campylobacter coli is prevalent among trade pigs in Kafanchan, Nigeria and is distributed across four of the five states from which trade pigs were sourced. Adequate hand hygiene is recommended for farmers, traders and Veterinary professionals handling pigs to prevent the transmission of this zoonosis to humans.

  11. Inhibition of Escherichia Coli, Salmonella and Staphylococcus ...

    African Journals Online (AJOL)

    Escherichia coli O157:H7, Salmonella typhimurium and Staphylococcus. aureus are of great concern to the food industry, especially in foods stored under refrigerated conditions where, unlike most food-borne pathogens are able to multiply. This investigation was conducted to study the inhibitory effect of some spice ...

  12. (ESBL) producing Escherichia coli and Klebsiella pneumoniae

    African Journals Online (AJOL)

    Emerging antibiotic resistance due to extended spectrum β-lactamase (ESBL) production limited the use of β-lactam antibiotics against Escherichia coli and Klebsiella pneumoniae. This observational study was conducted at the Microbiology department of the Children's Hospital, Lahore Pakistan, from June, 2009 to ...

  13. Mutagenic DNA repair in Escherichia coli

    International Nuclear Information System (INIS)

    Bridges, B.A.; Sharif, Firdaus

    1986-01-01

    The authors report a study of the misincorporation step in excision proficient umuC Escherichia coli as revealed by delayed photoreversal and show that it parallels the loss of photoreversibility of mutations induced in isogenic umu + bacteria; in both cases the end-point was mutation to streptomycin resistance. (author)

  14. Emergence of Quinolone Resistance amongst Escherichia coli ...

    African Journals Online (AJOL)

    Rate of resistance was 22.3% showing an increase in quinolone resistance when ... FQR E. coli was more common in patients with urinary tract infection (22.9%). ... in the faeces of healthy adults was 22.9%, 6.7% in children and 22.2% in avian. ... thereby aiding the spread of antibiotic resistant strains from avians to human ...

  15. Antibiotic resistance properties of uropathogenic Escherichia coli ...

    African Journals Online (AJOL)

    Purpose: To investigate the antibiotic resistance pattern of uropathogenic Escherichia coli (UPEC) strains isolated from pregnant women with history of recurrent urinary tract infections (RUTIs) and healthy pregnant women. Methods: A total of 485 high vaginal swab specimens were collected from pregnant women with ...

  16. Prevalence of Arcobacter, Escherichia coli, Staphylococcus aureus ...

    African Journals Online (AJOL)

    In this study, varying level of resistance of Escherichia coli 66(84.6%), Salmonella 6(100%) and Arcobacter 57(100%) to amoxicillin was observed. The susceptibility pattern indicates that the bacterial isolates exhibited a varying level of resistance to two or more antimicrobial agents with maximum resistance to amoxicillin.

  17. E.coli O157:H7

    Directory of Open Access Journals (Sweden)

    Treor Francis Fernandez

    2008-06-01

    Full Text Available The serious nature of the symptoms of haemorrhagic colitis and HUS and the apparent low infectious dose (<100 cells of E.coli O157:H7 places this food borne pathogen a most serious of known food borne pathogens. Persuasive evidence suggests that healthy cattle are a reservoir of O157 and they can enter the food chain to provide a source of exposure for humans. A possible route of transmission of O157 VTEC may involve infections initially in calves that shed their organism into faecal slurry that may be used on grazing grass. This provides potential for infection of other animals from which the organism may contaminate milk or carcasses at slaughter. Possible sources of VTEC in healthy animals other E.coli O157:H7 than cattle and a wider range of foodstuffs require further investigation. Many features of E.coli O157:H7 strains remain poorly understood. It includes: (i Role of virulent genes in the animal, (ii Mechanism of evolution of the organism, (iii The progress of individual cases of E.coli O157:H7 infection, and (iv The difference in incidence of infection in different geographical areas. [Veterinary World 2008; 1(3.000: 83-87

  18. Leaner and meaner genomes in Escherichia coli

    DEFF Research Database (Denmark)

    Ussery, David

    2006-01-01

    A 'better' Escherichia coli K-12 genome has recently been engineered in which about 15% of the genome has been removed by planned deletions. Comparison with related bacterial genomes that have undergone a natural reduction in size suggests that there is plenty of scope for yet more deletions....

  19. ANTIMICIROBIAL SUSCEPTIBILITY PATTERNS OF Escherichia coli ...

    African Journals Online (AJOL)

    DR. AMINU

    A total of 56 and 24 strains of E. coli and Shigella sp. isolated from children less than five years with diarrhoea attending 3 ... parasitic infections, as well as food intolerance, reaction to ..... Escherichia coil 0157:H7 as a model of entry of a new.

  20. Cellular chain formation in Escherichia coli biofilms

    DEFF Research Database (Denmark)

    Vejborg, Rebecca Munk; Klemm, Per

    2009-01-01

    ; type I fimbriae expression significantly reduced cellular chain formation, presumably by steric hindrance. Cellular chain formation did not appear to be specific to E coli K-12. Although many urinary tract infection (UTI) isolates were found to form rather homogeneous, flat biofilms, three isolates...

  1. Escherichia coli in broiler chickens with airsacculitis

    Directory of Open Access Journals (Sweden)

    Leandro S. Machado

    2014-09-01

    Full Text Available ABSTRACT. Machado L.S., do Nascimento E.R., Pereira V.L.A., Abreu D.L.C., Gouvea R. & Santos L.M.M. 2014. [Escherichia coli in broiler chickens with airsacculitis.] Escherichia coli em frangos de corte com aerossaculite. Revista Brasileira de Medicina Veterinária, 36(3:261-265, 2014. Departamento de Medicina Veterinária Preventiva e Saúde Pública, Faculdade de Veterinária, Universidade Federal Fluminense, Rua Dr. Vital Brazil Filho 64, Vital Brazil, Niterói, RJ 24230-340, Brazil. E-mail: leandromachadovet@yahoo.com.br The Brazilian poultry industry grows each year and becomes increasingly representative in the production and export of products. The health care with poultry have accompanied and favored this evolution, however, respiratory agents that affect the weight and carcass quality, continue to cause great damage to the poultry industry. Airsacculitis is considered the main cause of total and partial condemnation of carcasses of broilers, and has been attributed to Mycoplasmosis mostly caused by Mycoplasma gallisepticum (MG and Mycoplasma synoviae (MS and Escherichia coli. The aim of this study was to relate the positivity of MG / MS and E. coli detected by PCR as a risk factor for airsacculitis in condemnation of broilers in Health Inspection Service. We studied 30 broiler poultry slaughtered in a slaughterhouse under Federal Sanitary Inspection, located in the State of Rio de Janeiro. 30 chickens were randomly collected from different lots and tracheas obtained in each PCR. DNA was extracted by phenol-chloroform method and amplified using pairs of “primer”specific for MG, MS and E. coli. Of the 30 chickens analyzed by PCR, 30% (9/30 had lesions in air sacs. None of the birds showed infection with MG and/or MS PCR, however 33.3% (3/9 birds were positive for airsacculitis iss gene from E.coli. E.coli found in broiler chickens that were negative for mycoplasma airsacculitis, implying the presence of such bacteria may be sufficient

  2. Genetic Transfer of Salmonella typhimurium and Escherichia coli Lipopolysaccharide Antigens to Escherichia coli K-12

    Science.gov (United States)

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

    1972-01-01

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

  3. In vivo and in vitro antibacterial activity of conglutinin, a mammalian plasma lectin

    DEFF Research Database (Denmark)

    Friis-Christiansen, P; Thiel, S; Svehag, S E

    1990-01-01

    of BALB/c mice with Salmonella typhimurium is mediated by conglutinin. Conglutinin also demonstrated antibacterial activity against E. coli and S. typhimurium in vitro. The expression of this activity required the presence of heat-labile serum factors and peritoneal exudate or spleen cells...

  4. Hemolytic Porcine Intestinal Escherichia coli without Virulence-Associated Genes Typical of Intestinal Pathogenic E. coli ▿ †

    Science.gov (United States)

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

    2011-01-01

    Testing 1,666 fecal or intestinal samples from healthy and diarrheic pigs, we obtained hemolytic Escherichia coli isolates from 593 samples. Focusing on hemolytic E. coli isolates without virulence-associated genes (VAGs) typical for enteropathogens, we found that such isolates carried a broad variety of VAGs typical for extraintestinal pathogenic E. coli. PMID:21965399

  5. Expression of maize prolamins in Escherichia Coli

    International Nuclear Information System (INIS)

    Wang, Szu-zhen; Esen, Asim

    1985-01-01

    We have constructed a cDNA expression library of developing corn (Zea manys L.) endosperm using plasmid pUC8 as vector and Escherichia coli strain DH1 as host. The expression library was screened with non-radioactive immunological probes to detect the expression of gamma-zein and alpha-zein. When anti-gamma-zein antibody was used as the probe, 23 colonies gave positive reactions. The lengths of cDNA inserts of the 23 colonies were found to be 250-900 base pairs. When anti-alpha zein antibody was used, however, fewer colonies gave positive reactions. The library was also screened by colony-hybridization with 32 P-labeled DNA probes. Based on immunological and hybridization screening of the library and other evidence, we conclude that alpha-zein was either toxic to E. coli cells or rapidly degraded whereas gamma-zein and its fragments were readily expressed. (author)

  6. Genes under positive selection in Escherichia coli

    DEFF Research Database (Denmark)

    Petersen, Lise; Bollback, Jonathan P; Dimmic, Matt

    2007-01-01

    We used a comparative genomics approach to identify genes that are under positive selection in six strains of Escherichia coli and Shigella flexneri, including five strains that are human pathogens. We find that positive selection targets a wide range of different functions in the E. coli genome......, including cell surface proteins such as beta barrel porins, presumably because of the involvement of these genes in evolutionary arms races with other bacteria, phages, and/or the host immune system. Structural mapping of positively selected sites on trans-membrane beta barrel porins reveals...... that the residues under positive selection occur almost exclusively in the extracellular region of the proteins that are enriched with sites known to be targets of phages, colicins, or the host immune system. More surprisingly, we also find a number of other categories of genes that show very strong evidence...

  7. Energetics of sodium efflux from Escherichia coli

    International Nuclear Information System (INIS)

    Borbolla, M.G.; Rosen, B.P.

    1984-01-01

    When energy-starved cells of Escherichia coli were passively loaded with 22 Na+, efflux of sodium could be initiated by addition of a source of metabolic energy. Conditions were established where the source of energy was phosphate bond energy, an electrochemical proton gradient, or both. Only an electrochemical proton gradient was required for efflux from intact cells. These results are consistent with secondary exchange of Na+ for H+ catalyzed by a sodium/proton antiporter

  8. Silver nanoparticle-E. coli colloidal interaction in water and effect on E. coli survival.

    Science.gov (United States)

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

    2009-11-15

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

  9. Secretion of clostridium cellulase by E. coli

    Science.gov (United States)

    Yu, Ida Kuo

    1998-01-01

    A gene, encoding an endocellulase from a newly isolated mesophilic Clostridium strain IY-2 which can digest bamboo fibers, cellulose, rice straw, and sawdust, was isolated by shotgun cloning in an E. coli expression plasmid pLC2833. E. coli positive clones were selected based on their ability to hydrolyze milled bamboo fibers and cellulose present in agar plates. One clone contained a 2.8 kb DNA fragment that was responsible for cellulase activity. Western blot analyses indicated that the positive clone produced a secreted cellulase with a mass of about 58,000 daltons that was identical in size to the subunit of one of the three major Clostridium cellulases. The products of cellulose digestion by this cloned cellulase were cellotetraose and soluble higher polymers. The cloned DNA contained signal sequences capable of directing the secretion of heterologous proteins from an E. coli host. The invention describes a bioprocess for the treatment of cellulosic plant materials to produce cellular growth substrates and fermentation end products suitable for production of liquid fuels, solvents, and acids.

  10. Environmental Escherichia coli: Ecology and public health implications - A review

    Science.gov (United States)

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

    2017-01-01

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

  11. The influence of headspace and dissolved oxygen level on growth and haemolytic BL enterotoxin production of a psychrotolerant Bacillus weihenstephanensis isolate on potato based ready-to-eat food products.

    Science.gov (United States)

    Samapundo, S; Everaert, H; Wandutu, J N; Rajkovic, A; Uyttendaele, M; Devlieghere, F

    2011-04-01

    The major objective of this study was to determine the influence of the initial headspace and dissolved O(2) level and vacuum packaging on growth and diarrhoeal enterotoxin production by Bacillus weihenstephanensis on potato based ready-to-eat food products. In general, the lower the initial headspace or dissolved O(2) level the slower the maximum growth rate (μ(max), log(10) CFU g(-1) d(-1)), the longer the lag phase duration (λ, d) and the smaller the maximum population density (N(max), log(10) CFU g(-1)) became. The slowest μ(max), the longest λ and the smallest N(max) were generally found for growth under vacuum packaging. This implies shorter shelf-lives will occur at higher initial headspace or dissolved O(2) levels as the growth of B. weihenstephanensis to the infective dose of 10(5) CFU g(-1) in such atmospheres takes a shorter time. Significant consumption of dissolved O(2) only occurred when growth shifted from the lag to the exponential phase and growth generally transitioned from the exponential to the stationary phase when the dissolved O(2) levels fell below ca. 75 ppb. Diarrhoeal enterotoxin production (determined via detection of the L2 component of haemolytic BL) was similar for growth under initial headspace O(2) levels of 1-20.9%, and was only reduced when growth took place under vacuum packaging. The reduction in L2 production when growth took place under vacuum was most probably related to the low final cell densities observed under this condition. Both growth and L2 production were inhibited over a 32-day incubation period at 7 °C by 40% CO(2) irrespective of the headspace or dissolved O(2) levels. The results illustrate the importance of residual O(2) and CO(2) on the shelf-stability and safety of modified atmosphere packaged potato based ready-to-eat food products with regards to B. weihenstephanensis. Copyright © 2010 Elsevier Ltd. All rights reserved.

  12. Evaluation of Petrifilm™ Select E. coli Count Plate medium to discriminate antimicrobial resistant Escherichia coli

    Directory of Open Access Journals (Sweden)

    Jensen Lars

    2008-09-01

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

  13. Production of caffeoylmalic acid from glucose in engineered Escherichia coli.

    Science.gov (United States)

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

    2018-07-01

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

  14. Side-by-side comparison of gene-based smallpox vaccine with MVA in nonhuman primates.

    Science.gov (United States)

    Golden, Joseph W; Josleyn, Matthew; Mucker, Eric M; Hung, Chien-Fu; Loudon, Peter T; Wu, T C; Hooper, Jay W

    2012-01-01

    Orthopoxviruses remain a threat as biological weapons and zoonoses. The licensed live-virus vaccine is associated with serious health risks, making its general usage unacceptable. Attenuated vaccines are being developed as alternatives, the most advanced of which is modified-vaccinia virus Ankara (MVA). We previously developed a gene-based vaccine, termed 4pox, which targets four orthopoxvirus antigens, A33, B5, A27 and L1. This vaccine protects mice and non-human primates from lethal orthopoxvirus disease. Here, we investigated the capacity of the molecular adjuvants GM-CSF and Escherichia coli heat-labile enterotoxin (LT) to enhance the efficacy of the 4pox gene-based vaccine. Both adjuvants significantly increased protective antibody responses in mice. We directly compared the 4pox plus LT vaccine against MVA in a monkeypox virus (MPXV) nonhuman primate (NHP) challenge model. NHPs were vaccinated twice with MVA by intramuscular injection or the 4pox/LT vaccine delivered using a disposable gene gun device. As a positive control, one NHP was vaccinated with ACAM2000. NHPs vaccinated with each vaccine developed anti-orthopoxvirus antibody responses, including those against the 4pox antigens. After MPXV intravenous challenge, all control NHPs developed severe disease, while the ACAM2000 vaccinated animal was well protected. All NHPs vaccinated with MVA were protected from lethality, but three of five developed severe disease and all animals shed virus. All five NHPs vaccinated with 4pox/LT survived and only one developed severe disease. None of the 4pox/LT-vaccinated animals shed virus. Our findings show, for the first time, that a subunit orthopoxvirus vaccine delivered by the same schedule can provide a degree of protection at least as high as that of MVA.

  15. Intradermal delivery of Shigella IpaB and IpaD type III secretion proteins: kinetics of cell recruitment and antigen uptake, mucosal and systemic immunity, and protection across serotypes.

    Science.gov (United States)

    Heine, Shannon J; Diaz-McNair, Jovita; Andar, Abhay U; Drachenberg, Cinthia B; van de Verg, Lillian; Walker, Richard; Picking, Wendy L; Pasetti, Marcela F

    2014-02-15

    Shigella is one of the leading pathogens contributing to the vast pediatric diarrheal disease burden in low-income countries. No licensed vaccine is available, and the existing candidates are only partially effective and serotype specific. Shigella type III secretion system proteins IpaB and IpaD, which are conserved across Shigella spp., are candidates for a broadly protective, subunit-based vaccine. In this study, we investigated the immunogenicity and protective efficacy of IpaB and IpaD administered intradermally (i.d.) with a double-mutant of the Escherichia coli heat-labile enterotoxin (dmLT) adjuvant using microneedles. Different dosage levels of IpaB and IpaD, with or without dmLT, were tested in mice. Vaccine delivery into the dermis, recruitment of neutrophils, macrophages, dendritic cells, and Langerhans cells, and colocalization of vaccine Ag within skin-activated APC were demonstrated through histology and immunofluorescence microscopy. Ag-loaded neutrophils, macrophages, dendritic cells, and Langerhans cells remained in the tissue at least 1 wk. IpaB, IpaD, and dmLT-specific serum IgG- and IgG-secreting cells were produced following i.d. immunization. The protective efficacy was 70% against Shigella flexneri and 50% against Shigella sonnei. Similar results were obtained when the vaccine was administered intranasally, with the i.d. route requiring 25-40 times lower doses. Distinctively, IgG was detected in mucosal secretions; secretory IgA, as well as mucosal and systemic IgA Ab-secreting cells, were seemingly absent. Vaccine-induced T cells produced IFN-γ, IL-2, TNF-α, IL-17, IL-4, IL-5, and IL-10. These results demonstrate the potential of i.d. vaccination with IpaB and IpaD to prevent Shigella infection and support further studies in humans.

  16. Side-by-side comparison of gene-based smallpox vaccine with MVA in nonhuman primates.

    Directory of Open Access Journals (Sweden)

    Joseph W Golden

    Full Text Available Orthopoxviruses remain a threat as biological weapons and zoonoses. The licensed live-virus vaccine is associated with serious health risks, making its general usage unacceptable. Attenuated vaccines are being developed as alternatives, the most advanced of which is modified-vaccinia virus Ankara (MVA. We previously developed a gene-based vaccine, termed 4pox, which targets four orthopoxvirus antigens, A33, B5, A27 and L1. This vaccine protects mice and non-human primates from lethal orthopoxvirus disease. Here, we investigated the capacity of the molecular adjuvants GM-CSF and Escherichia coli heat-labile enterotoxin (LT to enhance the efficacy of the 4pox gene-based vaccine. Both adjuvants significantly increased protective antibody responses in mice. We directly compared the 4pox plus LT vaccine against MVA in a monkeypox virus (MPXV nonhuman primate (NHP challenge model. NHPs were vaccinated twice with MVA by intramuscular injection or the 4pox/LT vaccine delivered using a disposable gene gun device. As a positive control, one NHP was vaccinated with ACAM2000. NHPs vaccinated with each vaccine developed anti-orthopoxvirus antibody responses, including those against the 4pox antigens. After MPXV intravenous challenge, all control NHPs developed severe disease, while the ACAM2000 vaccinated animal was well protected. All NHPs vaccinated with MVA were protected from lethality, but three of five developed severe disease and all animals shed virus. All five NHPs vaccinated with 4pox/LT survived and only one developed severe disease. None of the 4pox/LT-vaccinated animals shed virus. Our findings show, for the first time, that a subunit orthopoxvirus vaccine delivered by the same schedule can provide a degree of protection at least as high as that of MVA.

  17. Prophylactic Administration of Bacterially Derived Immunomodulators Improves the Outcome of Influenza Virus Infection in a Murine Model▿

    Science.gov (United States)

    Norton, Elizabeth B.; Clements, John D.; Voss, Thomas G.; Cárdenas-Freytag, Lucia

    2010-01-01

    Prophylactic or therapeutic immunomodulation is an antigen-independent strategy that induces nonspecific immune system activation, thereby enhancing host defense to disease. In this study, we investigated the effect of prophylactic immunomodulation on the outcome of influenza virus infection using three bacterially derived immune-enhancing agents known for promoting distinct immunological profiles. BALB/c mice were treated nasally with either cholera toxin (CT), a mutant form of the CT-related Escherichia coli heat-labile enterotoxin designated LT(R192G), or CpG oligodeoxynucleotide. Mice were subsequently challenged with a lethal dose of influenza A/PR/8/34 virus 24 h after the last immunomodulation treatment and either monitored for survival or sacrificed postchallenge for viral and immunological analysis. Treatment with the three immunomodulators prevented or delayed mortality and weight loss, but only CT and LT(R192G) significantly reduced initial lung viral loads as measured by plaque assay. Analysis performed 4 days postinfection indicated that prophylactic treatments with CT, LT(R192G), or CpG resulted in significantly increased numbers of CD4 T cells, B cells, and dendritic cells and altered costimulatory marker expression in the airways of infected mice, coinciding with reduced expression of pulmonary chemokines and the appearance of inducible bronchus-associated lymphoid tissue-like structures in the lungs. Collectively, these results suggest that, despite different immunomodulatory mechanisms, CT, LT(R192G), and CpG induce an initial inflammatory process and enhance the immune response to primary influenza virus challenge while preventing potentially damaging chemokine expression. These studies provide insight into the immunological parameters and immune modulation strategies that have the potential to enhance the nonspecific host response to influenza virus infection. PMID:20053748

  18. Replication and Transcription of Eukaryotic DNA in Esherichia coli

    Science.gov (United States)

    Morrow, John F.; Cohen, Stanley N.; Chang, Annie C. Y.; Boyer, Herbert W.; Goodman, Howard M.; Helling, Robert B.

    1974-01-01

    Fragments of amplified Xenopus laevis DNA, coding for 18S and 28S ribosomal RNA and generated by EcoRI restriction endonuclease, have been linked in vitro to the bacterial plasmid pSC101; and the recombinant molecular species have been introduced into E. coli by transformation. These recombinant plasmids, containing both eukaryotic and prokaryotic DNA, replicate stably in E. coli. RNA isolated from E. coli minicells harboring the plasmids hybridizes to amplified X. laevis rDNA. Images PMID:4600264

  19. Characterization of diarrhoeagenic Escherichia coli isolates in Jordanian children.

    Science.gov (United States)

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

    2003-01-01

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

  20. 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....

  1. Impact of dry chilling on the genetic diversity of Escherichia coli on beef carcasses and on the survival of E. coli and E. coli O157.

    Science.gov (United States)

    Visvalingam, Jeyachchandran; Liu, Yang; Yang, Xianqin

    2017-03-06

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

  2. Translational coupling in Escherichia coli of a heterologous Bacillus subtilis-Escherichia coli gene fusion.

    OpenAIRE

    Zaghloul, T I; Doi, R H

    1986-01-01

    The efficient expression in Escherichia coli of the Tn9-derived chloramphenicol acetyltransferase (EC 2.3.1.28) gene fused distal to the promoter and N terminus of the Bacillus subtilis aprA gene was dependent on the initiation of translation from the ribosome-binding site in the aprA gene.

  3. ELECTROPHORETIC MOBILITIES OF ESCHERICHIA COLI 0157:H7 AND WILD-TYPE ESCHERICHIA COLI STRAINS

    Science.gov (United States)

    The electrophoretic mobility (EPM) of a number of human-virulent and "wild-type" Escherichia coli strains in phosphate buffered water was measured. The impact of pH, ionic strength, cation type (valence) and concentration, and bacterial strain on the EPM was investigated. Resul...

  4. Claudin-4 Overexpression in Epithelial Ovarian Cancer Is Associated with Hypomethylation and Is a Potential Target for Modulation of Tight Junction Barrier Function Using a C-Terminal Fragment of Clostridium perfringens Enterotoxin

    Directory of Open Access Journals (Sweden)

    Babak Litkouhi

    2007-04-01

    Full Text Available BACKGROUND: Claudin-4, a tight junction (TJ protein and receptor for the C-terminal fragment of Clostridium perfringens enterotoxin (C-CPE, is overexpressed in epithelial ovarian cancer (EOC. Previous research suggests DNA methylation is a mechanism for claudin-4 overexpression in cancer and that C-CPE acts as an absorption-enhancing agent in claudin-4expressing cells. We sought to correlate claudin-4 overexpression in EOC with clinical outcomes and TJ barrier function, investigate DNA methylation as a mechanism for overexpression, and evaluate the effect of C-CPE on the TJ. METHODS: Claudin-4 expression in EOC was quantified and correlated with clinical outcomes. Claudin-4 methylation status was determined, and claudin-4-negative cell lines were treated with a demethylating agent. Electric cell-substrate impedance sensing was used to calculate junctional (paracellular resistance (Rb in EOC cells after claudin-4 silencing and after C-CPE treatment. RESULTS: Claudin4 overexpression in EOC does not correlate with survival or other clinical endpoints and is associated with hypomethylation. Claudin-4 overexpression correlates with Rb and C-CPE treatment of EOC cells significantly decreased Rb in a dose- and claudin-4-dependent noncytotoxic manner. CONCLUSIONS: C-CPE treatment of EOC cells leads to altered TJ function. Further research is needed to determine the potential clinical applications of C-CPE in EOC drug delivery strategies.

  5. Experimental investigation into the effects of irradiation with mixed neutron-gamma-rays on the immune system as demonstrated by the model of immunity to Staphylococcal Enterotoxin B in rabbits

    International Nuclear Information System (INIS)

    Kraus, W.

    1984-01-01

    Using the model of immunisation of rabbits with Staphylococcal Enterotoxin B the influence of neutron radiation on the antibody response was investigated. Four groups were formed, which differed by the moment of irradiation with regard to the moment of immunisation and re-immunisation, and were irradiated with neutron-rays of 200 rad and 300 rad doses. Both doses were each given before and after vaccination, respectively before and after re-vaccination. The antibody response has been evaluated by the Radio-Immuno-Assay (RIA): Neutron-radiation given 24 hours before vaccination effects a stronger immune suppression than given 24 hours after vaccination. By pre-antigenic radiation a secondary immune response is more suppressed than by radiation following the antigen; the recovery of lymphoid tissue, however, takes place in a shorter time than in case of radiation before or after a primary vaccination. The secondary antibody response to a re-vaccination is not influenced by a subsequent neutron-radiation. The formation of secondary antibodies is not as radiosensitive as the formation of primary ones. By a neutron-radiation preformed antibodies are hardly damaged. (orig./MG) [de

  6. Organization and ELISA-Based Results of the First Proficiency Testing to Evaluate the Ability of European Union Laboratories to Detect Staphylococcal Enterotoxin Type B (SEB in Buffer and Milk

    Directory of Open Access Journals (Sweden)

    Yacine Nia

    2016-09-01

    Full Text Available The aim of this work was to organize the first proficiency test (PT dedicated to staphylococcal enterotoxin B (SEB detection in milk and buffer solutions. This paper describes the organization of the PT trial according to EN ISO 17043 requirements. Characterization of the SEB stock solution was performed using SDS-PAGE and SE-specific ELISA, and amino acid analysis was used to assign its protein concentration. The solution was then used to prepare six PT materials (four milk and two buffer batches at a ng/g toxin level, which included one blank and one SEA-containing milk as specificity control. Suitable material homogeneity and stability were assessed using screening and quantitative ELISAs. Among the methods used by the participants, ELISA-based methods demonstrated their efficiency for the detection of SEB in both simple and complex matrices. The results serve as a basis for further improving the detection capabilities in expert laboratories and can therefore be considered as a contribution to biopreparedness.

  7. Bacteroides fragilis Enterotoxin Induces Formation of Autophagosomes in Endothelial Cells but Interferes with Fusion with Lysosomes for Complete Autophagic Flux through a Mitogen-Activated Protein Kinase-, AP-1-, and C/EBP Homologous Protein-Dependent Pathway.

    Science.gov (United States)

    Ko, Su Hyuk; Jeon, Jong Ik; Myung, Hyun Soo; Kim, Young-Jeon; Kim, Jung Mogg

    2017-10-01

    Bacteroides fragilis enterotoxin (BFT), a virulence factor of enterotoxigenic B. fragilis (ETBF), plays an essential role in mucosal inflammation. Although autophagy contributes to the pathogenesis of diverse infectious diseases, little is known about autophagy in ETBF infection. This study was conducted to investigate the role of BFT in the autophagic process in endothelial cells (ECs). Stimulation of human umbilical vein ECs (HUVECs) with BFT increased light chain 3 protein II (LC3-II) conversion from LC3-I and protein expression of p62, Atg5, and Atg12. In addition, BFT-exposed ECs showed increased indices of autophagosomal fusion with lysosomes such as LC3-lysosome-associated protein 2 (LAMP2) colocalization and the percentage of red vesicles monitored by the expression of dual-tagged LC3B. BFT also upregulated expression of C/EBP homologous protein (CHOP), and inhibition of CHOP significantly increased indices of autophagosomal fusion with lysosomes. BFT activated an AP-1 transcription factor, in which suppression of AP-1 activity significantly downregulated CHOP and augmented autophagosomal fusion with lysosomes. Furthermore, suppression of Jun N-terminal protein kinase (JNK) mitogen-activated protein kinase (MAPK) significantly inhibited the AP-1 and CHOP signals, leading to an increase in autophagosomal fusion with lysosomes in BFT-stimulated ECs. These results suggest that BFT induced accumulation of autophagosomes in ECs, but activation of a signaling pathway involving JNK, AP-1, and CHOP may interfere with complete autophagy. Copyright © 2017 American Society for Microbiology.

  8. Enteropathogenic Escherichia coli: foe or innocent bystander?

    Science.gov (United States)

    Hu, Jia; Torres, Alfredo G.

    2015-01-01

    Enteropathogenic Escherichia coli (EPEC) remain one the most important pathogens infecting children and they are one of the main causes of persistent diarrhea worldwide. Historically, typical EPEC (tEPEC), defined as those isolates with the attaching and effacement (A/E) genotype (eae+), which possess bfpA+ and lack the stx- genes are found strongly associated with diarrheal cases. However, occurrence of atypical EPEC (aEPEC; eae+ bfpA- stx-) in diarrheal and asymptomatic hosts has made investigators question the role of these pathogens in human disease. Current epidemiological data is helping answering the question whether EPEC is mainly a foe or an innocent bystander during infection. PMID:25726041

  9. Dynamics of chromosome segregation in Escherichia coli

    DEFF Research Database (Denmark)

    Nielsen, Henrik Jørck

    2007-01-01

    Since the 1960’es the conformation and segregation of the chromosome in Escherichia coli has been a subject of interest for many scientists. However, after 40 years of research, we still know incredibly little about how the chromosome is organized inside the cell, how it manages to duplicate...... this incredibly big molecule and separate the two daughter chromosomes and how it makes sure that the daughter cells receives one copy each. The fully extended chromosome is two orders of magnitude larger than the cell in which it is contained. Hence the chromosome is heavily compacted in the cell...

  10. Escherichia coli photoreactivating enzyme: purification and properties

    International Nuclear Information System (INIS)

    Snapka, R.M.; Sutherland, B.M.

    1980-01-01

    Researchers have purified large quantities of Escherichia coli photoreactivating enzyme to apparent homogeneity and have studied its physical and chemical properties. The enzyme has a molecular weight of 36,800 and a S/sub 20,w/ 0 of 3.72 S. Amino acid analysis revealed an apparent absence of tryptophan, a low content of aromatic residues, and the presence of no unusual amino acids. The N terminus is arginine. The purified enzyme contained up to 13% carbohydrate by weight. The carbohydrate was composed of mannose, galactose, glucose, and N-acetylglucosamine. The enzyme is also associated with RNA containing uracil, adenine, guanine, and cytosine with no unusual bases detected

  11. Multiplex Genome Editing in Escherichia coli

    DEFF Research Database (Denmark)

    Ingemann Jensen, Sheila; Nielsen, Alex Toftgaard

    2018-01-01

    Lambda Red recombineering is an easy and efficient method for generating genetic modifications in Escherichia coli. For gene deletions, lambda Red recombineering is combined with the use of selectable markers, which are removed through the action of, e.g., flippase (Flp) recombinase. This PCR......-based engineering method has also been applied to a number of other bacteria. In this chapter, we describe a recently developed one plasmid-based method as well as the use of a strain with genomically integrated recombineering genes, which significantly speeds up the engineering of strains with multiple genomic...

  12. Identification of Genes Important for Growth of Asymptomatic Bacteriuria Escherichia coli in Urine

    DEFF Research Database (Denmark)

    Vejborg, Rebecca Munk; de Evgrafov, Mari Cristina Rodriguez; Phan, Minh Duy

    2012-01-01

    Escherichia coli is the most important etiological agent of urinary tract infections (UTIs). Unlike uropathogenic E. coli, which causes symptomatic infections, asymptomatic bacteriuria (ABU) E. coli strains typically lack essential virulence factors and colonize the bladder in the absence...

  13. Escherichia coli clearance after splenic autotransplants

    International Nuclear Information System (INIS)

    Marques, R.G.; Petroianu, A.; Oliveira, M.B.N.; Bernardo-Filho, M.; Portela, M.C.

    2002-01-01

    Background: Splenic autotransplantation seems to be the only alternative for preservation of splenic tissue, after total splenectomy. The present study was carried out to analyze Escherichia coli depuration by mononuclear phagocyte system organs after total splenectomy and splenic autotransplantation. Methods: We utilized an experimental model including young and adult Wistar rats, of both sexes, submitted to total splenectomy and splenic autotransplantation. The evaluation method was intravenous inoculation of a suspension of Escherichia coli labeled with technetium-99m. We analyzed bacteria uptake by mononuclear phagocyte system organs and bacteria remnant in the bloodstream. Results: There was no difference between young and adult animals in bacteria uptake by mononuclear phagocyte system organs. In the comparison of groups, it was found out that the mean percent uptake by spleen and liver of animals in the control group was higher than that observed for animals with splenic implants. However, bacteria uptake in the lung was higher in the splenic implant group than in the control group. Although spleen bacteria uptake in the control group animals has been higher than that of animals in the splenic implant group, the remnant bacteria in the bloodstream was similar. Animals submitted to isolated total splenectomy showed higher bacteria remnant in the bloodstream than animals of the control group or the group submitted to total splenectomy combined with splenic autotransplantation. Conclusion: Our results indicate that autogenous splenic implant is efficacious in bacteria depuration in rats, by means of their macrophages phagocytosis. In addition, it does not modify bacteria removal function of liver and lung

  14. Plasmid Conjugation in E. coli and Drug Resistance | Igwe ...

    African Journals Online (AJOL)

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

  15. Changes in Escherichia coli resistance to co-trimoxazole in ...

    African Journals Online (AJOL)

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

  16. Escherichia coli growth modeling using neural network | Shamsudin ...

    African Journals Online (AJOL)

    technique that has the ability to predict with efficient and good performance. Using NARX, a highly accurate model was developed to predict the growth of Escherichia coli (E. coli) based on pH water parameter. The multiparameter portable sensor and spectrophotometer data were used to build and train the neural network.

  17. Growth modeling of uropathogenic Escherichia coli in ground chicken meat

    Science.gov (United States)

    Extraintestinal Pathogenic Escherichia coli (ExPEC), including Uropathogenic E. coli (UPEC), are common contaminants in poultry meat, and are a major pathogen associated with inflammatory bowel disease, ulcerative colitis, sepsis, and urinary tract infections. The purpose of this study was to determ...

  18. Antimicrobial susceptibilities of avian Escherichia coli isolates in ...

    African Journals Online (AJOL)

    Colibacillosis is a poultry disease of economic importance in Iran and all around the world. The aim of this study is to test the antibiotic sensitivity of Escherichia coli strains which were isolated in Tabriz. A total of 100 E. coli strains isolated from avian colibacillosis of 50 farms from 2008 to 2009 in Tabriz, were investigated for ...

  19. Prevalence and antibiogram of Escherichia coli O157 isolated from ...

    African Journals Online (AJOL)

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

  20. Antibiotic resistant Salmonella and Escherichia coli isolated from ...

    African Journals Online (AJOL)

    Results: A hundred and four indigenous chicken rectal swabs were analysed, of which 67.3% were contaminated with Escherichia coli and 12.5% with Salmonella typhimurium. Seventy Escherichia coli isolates showed resistance phenotypes to one, two or more antibiotics. The most common antimicrobial resistance pattern ...

  1. Effect of high pressurized carbon dioxide on Escherichia coli ...

    African Journals Online (AJOL)

    Carbon dioxide at high pressure can retard microbial growth and sometimes kill microorganisms depending on values of applied pressure, temperature and exposure time. In this study the effect of high pressurised carbon dioxide (HPCD) on Escherichia coli was investigated. Culture of E. coli was subjected to high ...

  2. Prevalence of Aeromonas species and Escherichia coli in stool ...

    African Journals Online (AJOL)

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

  3. Adsorption of Escherichia coli Using Bone Char | Rezaee | Journal ...

    African Journals Online (AJOL)

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

  4. Anthranoid self-medication causing rapid development of melanosis coli

    NARCIS (Netherlands)

    M. Willems; H.R. van Buuren (Henk); R.R. de Krijger (Ronald)

    2003-01-01

    textabstractIt is widely known that long-term use of anthranoid-containing laxatives is the cause of melanosis coli. We describe a case of melanosis coli, which occurred in a 39-year-old liver transplant patient who took an over-the-counter product containing aloe, rheum and

  5. Draft Genome Sequence of Escherichia coli K-12 (ATCC 10798)

    OpenAIRE

    Dimitrova, Daniela; Engelbrecht, Kathleen C.; Putonti, Catherine; Koenig, David W.; Wolfe, Alan J.

    2017-01-01

    ABSTRACT Here, we present the draft genome sequence of Escherichia coli ATCC 10798. E.?coli ATCC 10798 is a K-12 strain, one of the most well-studied model microorganisms. The size of the genome was 4,685,496?bp, with a G+C content of 50.70%. This assembly consists of 62 contigs and the F plasmid.

  6. Chromatin architecture and gene expression in Escherichia coli

    DEFF Research Database (Denmark)

    Willenbrock, Hanni; Ussery, David

    2004-01-01

    Two recent genome-scale analyses underscore the importance of DNA topology and chromatin structure in regulating transcription in Escherichia coli.......Two recent genome-scale analyses underscore the importance of DNA topology and chromatin structure in regulating transcription in Escherichia coli....

  7. Genomic Comparative Study of Bovine Mastitis Escherichia coli.

    Science.gov (United States)

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

    2016-01-01

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

  8. 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...

  9. Antibiotic Resistance and Virulence Properties in Escherichia coli ...

    African Journals Online (AJOL)

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

  10. Incidence of Escherichia coli  - Glucuronidase Positive on Goat Milk

    Directory of Open Access Journals (Sweden)

    Zorica Voşgan

    2016-11-01

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

  11. Interaction of Escherichia coli with growing salad spinach plants.

    Science.gov (United States)

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

    2003-10-01

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

  12. Antibiotic Resistance of Escherichia coli Isolated from Healthy Food ...

    African Journals Online (AJOL)

    It was concluded from the study that healthy food animals form a reservoir of multiple resistant E. coli which may be transmitted to humans through the food chain. Thus, continued surveillance of E. coli obtained from food production continuum is merited to identify emerging antimicrobial-resistant phenotypes. The Kenya ...

  13. Expression of green fluorescent protein (GFPuv) in Escherichia coli ...

    African Journals Online (AJOL)

    Administrator

    The recombinant green fluorescent protein (GFPuv) was expressed by transformed cells of Escherichia coli DH5-α grown in LB/amp broth at 37oC, for 8 h and 24 h. To evaluate the effectiveness of different parameters to improve the expression of GFPuv by E. coli, four variable culturing conditions were set up for assays by ...

  14. ESBL-Producing Escherichia coli

    DEFF Research Database (Denmark)

    Hertz, Frederik Boetius

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

  15. No evidence for a bovine mastitis Escherichia coli pathotype.

    Science.gov (United States)

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

    2017-05-08

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

  16. Colonization of Enteroaggregative Escherichia coli and Shiga toxin-producing Escherichia coli in chickens and humans in southern Vietnam

    NARCIS (Netherlands)

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

    2016-01-01

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

  17. Initiation of Replication in Escherichia coli

    DEFF Research Database (Denmark)

    Frimodt-Møller, Jakob

    The circular chromosome of Escherichia coli is replicated by two replisomes assembled at the unique origin and moving in the opposite direction until they meet in the less well defined terminus. The key protein in initiation of replication, DnaA, facilitates the unwinding of double-stranded DNA...... to single-stranded DNA in oriC. Although DnaA is able to bind both ADP and ATP, DnaA is only active in initiation when bound to ATP. Although initiation of replication, and the regulation of this, is thoroughly investigated it is still not fully understood. The overall aim of the thesis was to investigate...... the regulation of initiation, the effect on the cell when regulation fails, and if regulation was interlinked to chromosomal organization. This thesis uncovers that there exists a subtle balance between chromosome replication and reactive oxygen species (ROS) inflicted DNA damage. Thus, failure in regulation...

  18. Control of Ribosome Synthesis in Escherichia coli

    DEFF Research Database (Denmark)

    Molin, Søren; Meyenburg, K. von; Måløe, O.

    1977-01-01

    The rate of ribosome synthesis and accumulation in Escherichia coli during the transition after an energy source shift-down was analyzed. The shift was imposed on cultures of stringent and relaxed strains growing in glucose minimal medium by the addition of the glucose analogue {alpha...... and to estimate the transcription time for the rRNA operon under different conditions. In steady states of growth with growth rates ranging from 0.75 to 2.3 doublings/h, as well as during the transition after a shift-down, the transcription time of the rRNA operon was constant. The rate of synthesis of r......RNA correlated during this transition – in contrast to the rate of accumulation (M. T. Hansen et al., J. Bacteriol. 122: 585-591, 1975) – with the ppGpp pool in the same way as has been observed during partial amino acid starvation....

  19. Repair replication in permeabilized Escherichia coli

    International Nuclear Information System (INIS)

    Masker, W.E.; Simon, T.J.; Hanawalt, P.C.

    1975-01-01

    We have examined the modes of DNA synthesis in Escherichia coli strains made permeable to nucleoside triphosphates by treatment with toluene. In this quasi in vitro system, polymerase-I-deficient mutants exhibit a nonconservative mode of synthesis with properties expected for the resynthesis step of excision-repair. This uv-stimulated DNA synthesis can be performed by either DNA polymerase II or III and it also requires the uvrA gene product. It requires the four deoxynucleoside triphosphates; but, in contrast to the semiconservative mode, the ATP requirement can be partially satisfied by other nucleoside triphosphates. The ATP-dependent recBC nuclease is not involved. The observed uv-stimulated mode of DNA synthesis may be part of an alternate excision-repair mechanism which supplements or complements DNA-polymerase-I-dependent repair in vivo

  20. Progressive segregation of the Escherichia coli chromosome

    DEFF Research Database (Denmark)

    Nielsen, Henrik Jørck; Youngren, Brenda; Hansen, Flemming G.

    2006-01-01

    We have followed the fate of 14 different loci around the Escherichia coli chromosome in living cells at slow growth rate using a highly efficient labelling system and automated measurements. Loci are segregated as they are replicated, but with a marked delay. Most markers segregate in a smooth...... temporal progression from origin to terminus. Thus, the overall pattern is one of continuous segregation during replication and is not consistent with recently published models invoking extensive sister chromosome cohesion followed by simultaneous segregation of the bulk of the chromosome. The terminus......, and a region immediately clockwise from the origin, are exceptions to the overall pattern and are subjected to a more extensive delay prior to segregation. The origin region and nearby loci are replicated and segregated from the cell centre, later markers from the various positions where they lie...

  1. Nanotextile membranes for bacteria Escherichia coli capturing

    Directory of Open Access Journals (Sweden)

    Jaroslav Lev

    2010-01-01

    Full Text Available The article describes an experimental study dealing with the possibility of nanotextile materials usa­ge for microbiologically contaminated water filtration. The aim of the study is to verify filtration ability of different nanotextile materials and evaluate the possibilities of practical usage. Good detention ability of these materials in the air filtration is the presumption for nanotextile to be used for bacteria filtration from a liquid. High nanotextile porosity with the nanotextile pores dimensions smaller than a bacteria size predicates the possibility of a successful usage of these materials. For the experiment were used materials made from electrospinning nanofibres under the label PA612, PUR1, PUR2 s PUR3 on the supporting unwoven textiles (viscose and PP. As a model simulation of the microbial contamination, bacteria Escherichia coli was chosen. Contaminated water was filtered during the overpressure activity of 105Pa on the input side of the filter from the mentioned material. After three-day incubation on the nutrient medium, cultures found in the samples before and after filtration were compared. In the filtrated water, bacteria E. coli were indicated, which did not verify the theoretical presumptions about an absolut bacteria detention. However, used materials caught at least 94% of bacteria in case of material PUR1 and up to 99,996% in case of material PUR2. These results predict the possibility of producing effective nanotextile filters for microbiologically contaminated water filtration.Recommendation: For the production of materials with better filtrating qualities, experiments need to be done, enabling better understanding of the bacteria detention mechanisms on the nanotextile material, and parameters of the used materials that influence the filtrating abilities need to be verified.

  2. Produção de enterotoxinas e da toxina da síndrome do choque tóxico por cepas de Staphylococcus aureus isoladas na mastite bovina Production of enterotoxins and toxic shock syndrome toxin by Staphylococcus aureus strains isolated from bovine mastitis

    Directory of Open Access Journals (Sweden)

    A. Nader Filho

    2007-10-01

    Full Text Available A total of 72 strains of Staphylococcus aureus were examined for the production of staphylococcal enterotoxins (SE A, B, C, D and toxic shock syndrome toxin (TSST-1. The strains were isolated from milk samples from cows with mastitis in dairy herds of São Paulo State, Brazil. Off 72 isolates, 38 (52.8% produced SEA, 38 (52.8% SEB, 32 (44.4% SED, 28 (38.9% SEC and 27 (37.5% TSST-1. From the 72 strains, 66 (91.7% produced, at least, one or more toxin, including TSST-1.

  3. Genome analysis of E. coli isolated from Crohn's disease patients.

    Science.gov (United States)

    Rakitina, Daria V; Manolov, Alexander I; Kanygina, Alexandra V; Garushyants, Sofya K; Baikova, Julia P; Alexeev, Dmitry G; Ladygina, Valentina G; Kostryukova, Elena S; Larin, Andrei K; Semashko, Tatiana A; Karpova, Irina Y; Babenko, Vladislav V; Ismagilova, Ruzilya K; Malanin, Sergei Y; Gelfand, Mikhail S; Ilina, Elena N; Gorodnichev, Roman B; Lisitsyna, Eugenia S; Aleshkin, Gennady I; Scherbakov, Petr L; Khalif, Igor L; Shapina, Marina V; Maev, Igor V; Andreev, Dmitry N; Govorun, Vadim M

    2017-07-19

    Escherichia coli (E. coli) has been increasingly implicated in the pathogenesis of Crohn's disease (CD). The phylogeny of E. coli isolated from Crohn's disease patients (CDEC) was controversial, and while genotyping results suggested heterogeneity, the sequenced strains of E. coli from CD patients were closely related. We performed the shotgun genome sequencing of 28 E. coli isolates from ten CD patients and compared genomes from these isolates with already published genomes of CD strains and other pathogenic and non-pathogenic strains. CDEC was shown to belong to A, B1, B2 and D phylogenetic groups. The plasmid and several operons from the reference CD-associated E. coli strain LF82 were demonstrated to be more often present in CDEC genomes belonging to different phylogenetic groups than in genomes of commensal strains. The operons include carbon-source induced invasion GimA island, prophage I, iron uptake operons I and II, capsular assembly pathogenetic island IV and propanediol and galactitol utilization operons. Our findings suggest that CDEC are phylogenetically diverse. However, some strains isolated from independent sources possess highly similar chromosome or plasmids. Though no CD-specific genes or functional domains were present in all CD-associated strains, some genes and operons are more often found in the genomes of CDEC than in commensal E. coli. They are principally linked to gut colonization and utilization of propanediol and other sugar alcohols.

  4. Quantitative Brightness Analysis of Fluorescence Intensity Fluctuations in E. Coli.

    Directory of Open Access Journals (Sweden)

    Kwang-Ho Hur

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

  5. Molecular prophage typing of avian pathogenic Escherichia coli.

    Science.gov (United States)

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

    2013-03-23

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

  6. Asymptomatic bacteriuria Escherichia coli are live biotherapeutics for UTI.

    Science.gov (United States)

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

    2014-01-01

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

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

    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. Natural indoles, indole-3-carbinol (I3C and 3,3'-diindolylmethane (DIM, attenuate staphylococcal enterotoxin B-mediated liver injury by downregulating miR-31 expression and promoting caspase-2-mediated apoptosis.

    Directory of Open Access Journals (Sweden)

    Philip B Busbee

    Full Text Available Staphylococcal enterotoxin B (SEB is a potent superantigen capable of inducing inflammation characterized by robust immune cell activation and proinflammatory cytokine release. Exposure to SEB can result in food poisoning as well as fatal conditions such as toxic shock syndrome. In the current study, we investigated the effect of natural indoles including indole-3-carbinol (I3C and 3,3'-diindolylmethane (DIM on SEB-mediated liver injury. Injection of SEB into D-galactosamine-sensitized female C57BL/6 mice resulted in liver injury as indicated by an increase in enzyme aspartate transaminase (AST levels, induction of inflammatory cytokines, and massive infiltration of immune cells into the liver. Administration of I3C and DIM (40 mg/kg, by intraperitonal injection, attenuated SEB-induced acute liver injury, as evidenced by decrease in AST levels, inflammatory cytokines and cellular infiltration in the liver. I3C and DIM triggered apoptosis in SEB-activated T cells primarily through activation of the intrinsic mitochondrial pathway. In addition, inhibitor studies involving caspases revealed that I3C and DIM-mediated apoptosis in these activated cells was dependent on caspase-2 but independent of caspase-8, 9 and 3. In addition, I3C and DIM caused a decrease in Bcl-2 expression. Both compounds also down-regulated miR-31, which directly targets caspase-2 and influences apoptosis in SEB-activated cells. Our data demonstrate for the first time that indoles can effectively suppress acute hepatic inflammation caused by SEB and that this may be mediated by decreased expression of miR-31 and consequent caspase-2-dependent apoptosis in T cells.

  9. Escherichia coli O26 IN RAW BUFFALO MILK: PRELIMINARY RESULTS

    Directory of Open Access Journals (Sweden)

    A. Rella

    2013-02-01

    Full Text Available Escherichia coli O26 is considered to be one of the most important food-borne pathogen. In this study, 120 buffalo milk samples collected in Lazio and in Apulia regions were tested for the presence of E. coli O26. One buffalo milk sample (0,8% tested positive for E. coli O26; the isolate was positive at the verocytotoxicity test and it showed resistance properties to different antimicrobial classes. These preliminary results highlight the need to monitor the foods of animal origin used for production and eaten by a wide range of persons, respect VTEC organism.

  10. Spontaneous Escherichia coli Meningitis Associated with Hemophagocytic Lymphohistiocytosis

    Directory of Open Access Journals (Sweden)

    Kuo-Hsuan Chang

    2006-01-01

    Full Text Available Spontaneous Escherichia coli meningitis has not been previously reported in association with hemophago-cytic lymphohistiocytosis (HLH. A previously healthy 72-year-old woman was admitted due to fever, nuchal rigidity, disturbed consciousness and splenomegaly. Anemia, thrombocytopenia and hyperfer-ritinemia developed on the 8th day of hospitalization. Cultures of cerebrospinal fluid and blood grew E. coli. Abundant macrophages overwhelmed erythrocytes in the bone marrow aspirate, confirming the presence of hemophagocytosis. E. coli meningitis was managed with a 40-day course of antibiotic treatment. However, the severity of anemia and thrombocytopenia progressed despite intensive transfusion therapy. The patient died of HLH on the 60th day of hospitalization.

  11. Findings of Escherichia coli and Enterococcus spp. in homemade cheese

    Directory of Open Access Journals (Sweden)

    Tambur Zoran

    2007-01-01

    Full Text Available During the period from February until March 2004, 108 samples of soft cheese originating from markets of Pancevo, Subotica and Belgrade were examined. Microbiological analyses of the cheese samples to the presence of Escherichia coli was performed using methods described in the Regulations on methods for performing microbiological analyses and super analyses of consumer articles, while the presence of bacteria Enteroccocus spp. was performed on the dexter agar. From 108 samples of soft cheese from the territories of Pancevo, Belgrade and Subotica were isolated: Enterococcus spp. from 96% and Escherichia coli from 69%, cheese samples. Verocytotoxic E.coli was not isolated from any of the taken cheese samples.

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

    Science.gov (United States)

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

    2016-10-01

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

  13. 75 FR 14607 - Small Entity Compliance Guide: Bottled Water: Total Coliform and E. coli

    Science.gov (United States)

    2010-03-26

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

  14. Alterations induced in Escherichia Coli cells by gamma radiation

    International Nuclear Information System (INIS)

    Kappke, J.; Schelin, H.R.; Paschuk, S.A.; Denyak, V.; Silva, E.R. da; Jesus, E.F.O. de; Lopes, R.T.; Carlin, N.; Toledo, E.S.

    2007-01-01

    Modifications occurred in Escherichia coli cells exposed to gamma radiation ( 60 Co source) were investigated. The irradiations were done at the LIN-COPPE laboratory of the UFRJ and the analysis at the Biology Department of the UTFPR. The E. coli cells were irradiated with 30, 60, 90, 120, 150, 180, 210, 240, 300, 480, 600 e 750 Gy doses. The samples were analyzed with Gram-stain, biochemical tests in EPM, MIO and Lysine Broth, Simmons Cytrate Medium and Rhamnose Broth, antibiogram and isolation of auxotrophic mutants. It was observed that for the received doses the E. coli did not show morphological alterations in the tests. Some E. Coli cells showed to be able to deaminade the L-tryptophan or they changed their sensibility for amoxillin and cephaloonine after the irradiation. The existence of aauxotrophic mutants after irradiation was also verified. (author)

  15. Distribution of Escherichia Coli as Soil Pollutant around Antang Landfills

    Science.gov (United States)

    Artiningsih, Andi; Zubair, Hazairin; Imran, A. M.; Widodo, Sri

    2018-03-01

    Tamangapa Antang Landfill locates around the residential area and faces an air and water pollution due to an open dumping system in its operation. The system arises a potential pollution in air, water and soil. Sampling was done surround the landfill in two parts, parallel and perpendicular to the ground water flow. This study shows the abundance of E. coli bacteria in soil around the Antang Landfills at depth of 10 to 20 cm (93x105 cfu/gr of soil) in the direction of groundwater flow. While in other locations the E. coli bacteria is not detected. The abundance of E. coli bacteria is a conjunction factor from landfill and human activities surround the area. The absence of E. coli bacteria in other location highly interpreted that the landfill is the major contributor of pollutant.

  16. The Escherichia coli transcriptome linked to growth fitness

    Directory of Open Access Journals (Sweden)

    Bei-Wen Ying

    2016-03-01

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

  17. Evolution in the Lab: Biocide Resistance in E.coli.

    Science.gov (United States)

    Welden, Charles W.; Hossler, Rex A.

    2003-01-01

    Describes a laboratory experiment on resistance to teach about evolution and issues of misuse of antimicrobial compounds. Investigates Escherichia coli's response to treatment of triclosan, a biocide used in consumer products. (Contains 12 references.) (YDS)

  18. A magnetic biosensor system for detection of E. coli

    KAUST Repository

    Li, Fuquan; Kosel, Jü rgen

    2013-01-01

    This work describes a device for detecting E. coli bacteria by manipulating superparamagnetic beads to a sensing area and immobilizing them in a trapping well. The trapping well replaces the biochemical immobilization layer, which is commonly used

  19. TRIMETHOPRIM-SULFAMETHOXAZOLE RESISTANCE IN SEWAGE ISOLATES OF ESCHERICHIA COLI

    Science.gov (United States)

    Sewage samples from seven locations in the United States were analyzed for Escherichia coli isolates which were resistant to trimethoprim-sulfamethoxazole (SXT). The prevalence rate of SXT resistant organisms varied between the different geographical locales. The majority of th...

  20. Rare Case of Polymicrobial Keratitis With Balantidium coli.

    Science.gov (United States)

    Hazarika, Manali; Pai H, Vijaya; Khanna, Vinay; Reddy, Harish; Tilak, Kriti; Chawla, Kiran

    2016-12-01

    To report a rare case of polymicrobial keratitis due to Balantidium coli and gram-negative bacteria, Pseudomonas aeruginosa and Klebsiella pneumoniae, in a soft contact lens (CL) wearer. We report a case of CL-related keratitis due to B. coli, P. aeruginosa, and K. pneumoniae. The culture of the corneal scrapings, the CL cleaning solution, and the CL revealed the growth of a rare ciliated parasite, B. coli, along with gram-negative bacteria, namely, P. aeruginosa and K. pneumoniae. The patient was successfully treated with topical broad-spectrum antibiotics and intravenous metronidazole. Polymicrobial keratitis has seldom been reported with B. coli as the causative agent. CL wear can be a risk factor for this infection. Treatment with topical antibiotics may not suffice, and the intravenous route of antiprotozoal drugs may be a useful adjunct. Increasing awareness, early diagnosis, and treatment may improve the final visual outcome.

  1. Ischemic colitis or melanosis coli: a case report

    Directory of Open Access Journals (Sweden)

    Nadeem Mohammed

    2007-09-01

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

  2. The Prevalence of Enterhaemorrhagic Escherichia Coli in children ...

    African Journals Online (AJOL)

    EHEC), the pathogenicity of other strains of Escherichia coli and other organisms in children presenting with and without diarrhoea in the hospital. Subjects and Methods: A total of 247 stool samples collected from children aged 1 month to 7 ...

  3. Peptide nucleic acid (PNA) antisense effects in Escherichia coli

    DEFF Research Database (Denmark)

    Good, L; Nielsen, P E

    1999-01-01

    Antisense peptide nucleic acid (PNA) can be used to control cell growth, gene expression and growth phenotypes in the bacteria Escherichia coli. PNAs targeted to the RNA components of the ribosome can inhibit translation and cell growth, and PNAs targeted to mRNA can limit gene expression with gene...... and sequence specificity. In an E. coli cell extract, efficient inhibition is observed when using PNA concentrations in the nanomolar range, whereas micromolar concentrations are required for inhibition in growing cells. A mutant strain of E. coli that is more permeable to antibiotics also is more susceptible...... to antisense PNAs than the wild type. This chapter details methods for testing the antisense activities of PNA in E. coli. As an example of the specific antisense inhibition possible, we show the effects of an anti-beta-galactosidase PNA in comparison to control PNAs. With improvements in cell uptake...

  4. GLYCOSYLATED YGHJ POLYPEPTIDES FROM ENTEROTOXIGENIC ESCHERICHIA COLI (ETEC)

    DEFF Research Database (Denmark)

    2017-01-01

    The present invention relates to glycosylated YghJ polypeptides from or derived from enterotoxigenic Escherichia coli (ETEC) that are immunogenic. In particular, the present invention relates to compositions or vaccines comprising the polypeptides and their application in immunization, vaccination...

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

    OpenAIRE

    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 al...

  6. Analysis of early-onset bloodstream infection due to Escherichia coli infection in premature babies

    OpenAIRE

    Chen, I-Lun; Huang, Hsin-Chun; Wu, Chih-Te; Ou-Yang, Mei-Chen; Chung, Mei-Yung; Chen, Chih-Cheng; Suen, Jau-Ling; Hung, Chih-Hsing

    2017-01-01

    Abstract In early-onset bacteremia among preterm neonates, Escherichia coli (E. coli) is the main pathogen and can cause a high mortality rate. Thus, the predictive factors of mortality and extended-spectrum ?-lactamase (ESBL)-producing E. coli in preterm babies with E. coli early-onset bacteremia were reported. We retrospectively reviewed preterm neonates who had E. coli bacteremia occurring within 3 days after birth between 2004 and 2015. Maternal and perinatal information were collected fr...

  7. Characterization of Climical and Commensal Escherichia coli Isolates from an Integrated Turkey Operation

    OpenAIRE

    Altekruse, Sean Fitzgerald

    2001-01-01

    Pathogenic E. coli infections cause approximately one quarter of disease losses in commercial turkey flocks. A small subgroup of E. coli causes most infections. Epidemiologic studies of this disease have been hindered by a lack of reliable markers to discriminate between pathogenic and fecal E. coli and by the diversity of poultry strains. Reliance on antimicrobials to control E. coli infections has caused widespread antimicrobial resistance. One hundred five clinical E. coli were obtaine...

  8. Metabolic engineering of Escherichia coli for the production of riboflavin

    OpenAIRE

    Lin, Zhenquan; Xu, Zhibo; Li, Yifan; Wang, Zhiwen; Chen, Tao; Zhao, Xueming

    2014-01-01

    Background Riboflavin (vitamin B2), the precursor of the flavin cofactors flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), is used commercially as an animal feed supplement and food colorant. E. coli is a robust host for various genetic manipulations and has been employed for efficient production of biofuels, polymers, amino acids, and bulk chemicals. Thus, the aim of this study was to understand the metabolic capacity of E. coli for the riboflavin production by modification...

  9. Draft Genome Sequence of Escherichia coli K-12 (ATCC 10798).

    Science.gov (United States)

    Dimitrova, Daniela; Engelbrecht, Kathleen C; Putonti, Catherine; Koenig, David W; Wolfe, Alan J

    2017-07-06

    Here, we present the draft genome sequence of Escherichia coli ATCC 10798. E. coli ATCC 10798 is a K-12 strain, one of the most well-studied model microorganisms. The size of the genome was 4,685,496 bp, with a G+C content of 50.70%. This assembly consists of 62 contigs and the F plasmid. Copyright © 2017 Dimitrova et al.

  10. Genes and proteins of Escherichia coli K-12.

    Science.gov (United States)

    Riley, M

    1998-01-01

    GenProtEC is a database of Escherichia coli genes and their gene products, classified by type of function and physiological role and with citations to the literature for each. Also present are data on sequence similarities among E.coli proteins, representing groups of paralogous genes, with PAM values, percent identity of amino acids, length of alignment and percent aligned. GenProtEC can be accessed at the URL http://www.mbl.edu/html/ecoli.html

  11. Predictors Of Non-Escherichia Coli Urinary Tract Infection.

    Science.gov (United States)

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

    2016-11-01

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

  12. Metabolic and Transcriptional Response to Cofactor Perturbations in Escherichia coli

    DEFF Research Database (Denmark)

    Holm, Anders Koefoed; Blank, L.M.; Oldiges, M.

    2010-01-01

    Metabolic cofactors such as NADH and ATP play important roles in a large number of cellular reactions, and it is of great interest to dissect the role of these cofactors in different aspects of metabolism. Toward this goal, we overexpressed NADH oxidase and the soluble F1-ATPase in Escherichia coli...... of redox and energy metabolism and should help in developing metabolic engineering strategies in E. coli....

  13. Physicochemical Factors: Impact on Spermagglutination Induced by Escherichia coli

    Directory of Open Access Journals (Sweden)

    Kiranjeet Kaur

    2014-02-01

    Full Text Available Motility is a sensitive parameter of sperm function which is predictive of its fertilization potential in vitro. The decrease in sperm motility may be associated with sperm agglutination and immobilization due to mere presence of bacteria or excretion of bacterial toxic products. Supplementation with various agents like sucrose, mannitol, calcium, and EDTA is well known to improve the sperm motility in vitro. The present study was designed to check any protective role exerted by the addition of different agents on spermatozoal motility against E. coli induced sperm agglutination. 52 semen specimens were screened for the presence of sperm-agglutinating strain of E. coli. Further, influence of various factors, namely, sugars, salts, and chelating agents was studied. Also, the impact of exposure to high temperature and alcohol on sperm-agglutinating efficiency of E. coli was observed. None of the factors could inhibit the sperm agglutination induced by E. coli, except high temperature suggesting the involvement of protein moiety. In addition, it was observed that agglutinating efficiency of E. coli was limited to spermatozoa and RBCs. It may be concluded that sperm-agglutinating property of E. coli is quite stable as various physicochemical factors tested did not show any negative effect on the same except high temperature.

  14. Incidence of Escherichia coli O157:H7 in Thailand

    International Nuclear Information System (INIS)

    Sukhumungoon, P.

    2015-01-01

    Entero hemorrhagic Escherichia coli (EHEC) especially serotype O157:H7 is one of the important food-borne pathogens because it is able to produce crucial toxins Shiga. However, the outbreak of this organism in Thailand has not been reported. Antibody to O157 antigen was detected in some Thai populations and Shiga toxin-producing E. coli were detected in low numbers of clinical specimens. Interestingly, some E. coli that showed positive to O157 fimbriae probe and lack of virulence gene were isolated from certain patients and one isolate of E. coli O157:H7 which possessed stx1, stx2v was detected in a normal child. In addition, the incidence of E. coli O157:H7 strains were monitored by the samples from cattle and retail beef in Thailand although their inability to produce toxins or produce in a low concentration was demonstrated. This review discusses the incidences of E. coli O157 in clinical and environmental samples of Thailand including the transmission possibility of this bacterium across the Thai border through food trade. (author)

  15. The presence of verotoxinogenic E. coli in some foods

    Directory of Open Access Journals (Sweden)

    Bostan K.

    2005-01-01

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

  16. Ecological and genetic determinants of plasmid distribution in Escherichia coli.

    Science.gov (United States)

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

    2016-11-01

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

  17. Anti E. coli Activity of Herbal Medicines: a Review

    Directory of Open Access Journals (Sweden)

    Nahid Rezaei

    2017-12-01

    Full Text Available Escherichia coli is the gram negative bacilli of Entrobacteriaceae family that commonly found in intestinal infections and many infections outside the intestine, like urinary tract infections (UTI, cholecystitis, wound infections, meningitis, septicemia, pulmonary infections, and many more. Plants are rich sources of bioactive compounds, hence they can be effective in a wide variety of diseases. The pandemic spread of multidrug-resistant (MDR bacteria (i.e., extended-spectrum b-lactamase-producing Enterobacteriaceae (ESBLPE, Carbapenemase-producing Enterobacteriaceae (CPE threaten healthcare Worldwide. The present review is a report of the most effective medicinal plants against E. coli. In this research, the required online database searches were conducted using the key words such as bacteria, E. coli and medicinal plants. Databases of Web of Science, PubMed, Scopus, Google Scholar, and ScienceDirect were explored to find and explore related articles. Since the incidence of E. coli is high, the aim of this study is to identify and report anti E. coli medicinal plants in Iran. The obtained results showed that there were 51 medicinal herbs that could be considered as the main medicinal plants capable of affecting E. coli.

  18. Antibiotic resistance of Verotoxigenic Escherichia coli isolated from vegetables

    Directory of Open Access Journals (Sweden)

    mojtaba boniadian

    2017-01-01

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

  19. Distribution of Diverse Escherichia coli between Cattle and Pasture.

    Science.gov (United States)

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

    2017-09-27

    Escherichia coli is widely considered to not survive for extended periods outside the intestines of warm-blooded animals; however, recent studies demonstrated that E. coli strains maintain populations in soil and water without any known fecal contamination. The objective of this study was to investigate whether the niche partitioning of E. coli occurs between cattle and their pasture. We attempted to clarify whether E. coli from bovine feces differs phenotypically and genotypically from isolates maintaining a population in pasture soil over winter. Soil, bovine fecal, and run-off samples were collected before and after the introduction of cattle to the pasture. Isolates (363) were genotyped by uidA and mutS sequences and phylogrouping, and evaluated for curli formation (Rough, Dry, And Red, or RDAR). Three types of clusters emerged, viz. bovine-associated, clusters devoid of cattle isolates and representing isolates endemic to the pasture environment, and clusters with both. All isolates clustered with strains of E. coli sensu stricto, distinct from the cryptic species Clades I, III, IV, and V. Pasture soil endemic and bovine fecal populations had very different phylogroup distributions, indicating niche partitioning. The soil endemic population was largely comprised of phylogroup B1 and had a higher average RDAR score than other isolates. These results indicate the existence of environmental E. coli strains that are phylogenetically distinct from bovine fecal isolates, and that have the ability to maintain populations in the soil environment.

  20. Tiamulin resistance mutations in Escherichia coli.

    Science.gov (United States)

    Böck, A; Turnowsky, F; Högenauer, G

    1982-01-01

    Forty "two-step" and 13 "three-step" tiamulin-resistant mutants of Escherichia coli PR11 were isolated and tested for alteration of ribosomal proteins. Mutants with altered ribosomal proteins S10, S19, L3, and L4 were detected. The S19, L3, and L4 mutants were studied in detail. The L3 and L4 mutations did not segregate from the resistance character in transductional crosses and therefore seem to be responsible for the resistance. Extracts of these mutants also exhibited an increased in vitro resistance to tiamulin in the polyuridylic acid and phage R17 RNA-dependent polypeptide synthesis systems, and it was demonstrated that this was a property of the 50S subunit. In the case of the S19 mutant, genetic analysis showed segregation between resistance and the S19 alteration and therefore indicated that mutation of a protein other than S19 was responsible for the resistance phenotype. The isolated ribosomes of the S19, L3, and L4 mutants bound radioactive tiamulin with a considerably reduced strength when compared with those of wild-type cells. The association constants were lower by factors ranging from approximately 20 to 200. When heated in the presence of ammonium chloride, these ribosomes partially regained their avidity for tiamulin. Images PMID:7050084

  1. Mutagenic DNA repair in Escherichia coli. VII

    International Nuclear Information System (INIS)

    Bridges, B.A.; Mottershead, R.P.

    1978-01-01

    Incubation of E. coli WP2 in the presence of chloramphenicol (CAP) for 90 min before and 60 min after γ-irradiation had no effect on the induction of Trp + mutations. Bacteria that had been treated with CAP for 90 min prior to UV irradiation showed normal or near normal yields of induced mutations to streptomycin or colicin E2 resistance. Most of these mutations lost their photoreversibility (indicating 'fixation') during continued incubation with CAP for a further 60 min after irradiation, during which time neither protein nor DNA synthesis was detectable. It is suggested that CAP-sensitive protein synthesis is not required for mutagenic (error-prone) repair of lesions in pre-existing DNA, arguing against an inducible component in this repair. In contrast the frequency of UV-induced mutations to Trp + (largely at suppressor loci) was drastically reduced by CAP pretreatment, confirming the need for an active replication fork for UV-mutagenesis at these loci. It is known from the work of others that CAP given after UV abolishes mutagenesis at these loci. It is concluded that CAP-sensitive protein synthesis (consistent with a requirement for an inducible function) is necessary for mutagenic repair only in newly-replicated DNA (presumably at daughter strand gaps) and not in pre-existing DNA. The data are consistent with but do not prove the hypothesis that CAP-sensitive and insensitive modes of mutagenesis reflect minor differences in the operation of a single basic mutagenic repair system. (Auth.)

  2. Immunopurification of adenomatous polyposis coli (APC) proteins

    Science.gov (United States)

    2013-01-01

    Background The adenomatous polyposis coli (APC) tumour suppressor gene encodes a 2843 residue (310 kDa) protein. APC is a multifunctional protein involved in the regulation of β-catenin/Wnt signalling, cytoskeletal dynamics and cell adhesion. APC mutations occur in most colorectal cancers and typically result in truncation of the C-terminal half of the protein. Results In order to investigate the biophysical properties of APC, we have generated a set of monoclonal antibodies which enable purification of recombinant forms of APC. Here we describe the characterisation of these anti-APC monoclonal antibodies (APC-NT) that specifically recognise endogenous APC both in solution and in fixed cells. Full-length APC(1–2843) and cancer-associated, truncated APC proteins, APC(1–1638) and APC(1–1311) were produced in Sf9 insect cells. Conclusions Recombinant APC proteins were purified using a two-step affinity approach using our APC-NT antibodies. The purification of APC proteins provides the basis for detailed structure/function analyses of full-length, cancer-truncated and endogenous forms of the protein. PMID:24156781

  3. Treatment of inflammatory bowel disease associated E. coli with ciprofloxacin and E. coli Nissle in the streptomycin-treated mouse intestine

    DEFF Research Database (Denmark)

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

    2011-01-01

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

  4. Association between enteropathogens and malnutrition in children aged 6-23 mo in Bangladesh: a case-control study.

    Science.gov (United States)

    Platts-Mills, James A; Taniuchi, Mami; Uddin, Md Jashim; Sobuz, Shihab Uddin; Mahfuz, Mustafa; Gaffar, Sm Abdul; Mondal, Dinesh; Hossain, Md Iqbal; Islam, M Munirul; Ahmed, Am Shamsir; Petri, William A; Haque, Rashidul; Houpt, Eric R; Ahmed, Tahmeed

    2017-05-01

    Background: Early exposure to enteropathogens has been associated with malnutrition in children in low-resource settings. However, the contribution of individual enteropathogens remains poorly defined. Molecular diagnostics offer an increase in sensitivity for detecting enteropathogens but have not been comprehensively applied to studies of malnutrition. Objective: We sought to identify enteropathogens associated with malnutrition in Bangladesh. Design: Malnourished children [weight-for-age z score (WAZ) children (WAZ >-1) of the same age and from the same community were enrolled as controls. Stools were collected at enrollment and, for cases, after a 5-mo nutritional intervention. Enrollment and follow-up stools were tested by quantitative polymerase chain reaction for 32 enteropathogens with the use of a custom-developed TaqMan Array Card. Results: Enteropathogen testing was performed on 486 cases and 442 controls upon enrollment and 365 cases at follow-up. At enrollment, the detection of enteroaggregative Escherichia coli (OR: 1.39; 95% CI: 1.05, 1.83), Campylobacter spp. (OR: 1.46; 95% CI: 1.11, 1.91), heat-labile enterotoxin-producing E. coli (OR: 1.55; 95% CI: 1.04, 2.33), Shigella /enteroinvasive E. coli (OR: 1.65; 95% CI: 1.10, 2.46), norovirus genogroup I (OR: 1.66; 95% CI: 1.23, 2.25), and Giardia (OR: 1.73; 95% CI: 1.20, 2.49) were associated with malnourished cases, and the total burden of these pathogens remained associated with malnutrition after adjusting for sociodemographic factors. The number of these pathogens at follow-up was negatively associated with the change in WAZ during the intervention (-0.10 change in WAZ per pathogen detected; 95% CI: -0.14, -0.06), whereas the number at enrollment was positively associated with the change in WAZ (0.05 change in WAZ per pathogen detected; 95% CI: 0.00, 0.10). Conclusions: A subset of enteropathogens was associated with malnutrition in this setting. Broad interventions designed to reduce the burden of

  5. Production and Purification Immunoglobulin against E. coli in Egg Yolk

    Directory of Open Access Journals (Sweden)

    Mohammadreza Nassiri

    2016-08-01

    Full Text Available Introduction Chicken is the only avian species in which polyclonal antibodies, like IgG is transported from the hen to the egg yolk in a similar manner as the transport of mammalian IgG from the mother to the fetus. Immunoglobulin Y in the chicken is transported to the egg and accumulates in the egg yolk in large quantities. IgY is an egg yolk antibody that has been used widely for treatment and prevention of infections in humans and animal. IgY is used for passive protection of the pathogen infections such as Escherichia coli, bovine and human rotavirus, bovine coronavirus, salmonella, staphylococcus and Pseudomonas. IgY is a promising candidate as an alternative to antibiotics. Eschericha coli strains of serotype O157: H7 belongs to a family of pathogenic E. coli called enterohemorrhagic E. coli (EHEC strains responsible for hemorrhagic colitis, bloody or non-bloody diarrhea, and hemolytic uremic syndrome in humans. This strain of E. coli pathogenises by adhering to host intestinal epithelium and forming bacterial colonies. The purpose of this study was to produce and purify immunoglobulin Y against E. coli O157:H7 and develop specific polyclonal anti E. coli antibody in the egg yolk. Materials and Methods Sixteen-week-old laying hens (Mashhad, Iran were kept in individual cages with food and water ad libitum. Immunization of hens was performed by intramuscularly injecting killed E. coli O157: H7 with an equal volume of Freund’s complete adjuvant into two sides of chest area (Sigma, USA for the first immunization. Two booster immunizations followed up using complete and incomplete Freund’s adjuvants in two weeks interval. Freund’s adjuvant without antigen was injected to the control group. Two weeks after the last injection, the eggs were collected daily for eight weeks, marked and stored at 4 ºC. In order to IgY purification, eggs were collected. Purification of IgY from egg yolk was based on Polson and using PEG6000. Finally, the

  6. Modeling the inactivation of Escherichia coli 0157:H7 and uropathogenic E.coli in ground chicken by high pressure processing and thymol

    Science.gov (United States)

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

  7. Lethality prediction for Escherichia coli 0157:H7 and Uropathogenic E. coli in ground chicken treated with high pressure processing and trans-cinnamaldehyde

    Science.gov (United States)

    Pathogenic Escherichia coli, intestinal (O157:H7) as well as extraintestinal types (Uropathogenic E. coli (UPEC)) are commonly found in many foods including chicken meat. In this study we compared the resistance of E. coli O157:H7 to UPEC in chicken meat under the stresses of high hydrostatic pressu...

  8. Modeling the inactivatin of Escherichia coli 0157:H7 and uropathogenic E. coli in ground beef by high pressure processing and citral

    Science.gov (United States)

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

  9. Occurrence and characterization of Shiga toxin-producing Escherichia coli O157:H7 and other non-sorbitol-fermenting E. coli in cattle and humans in urban areas of Morogoro, Tanzania

    DEFF Research Database (Denmark)

    Lupindu, Athumani M; Olsen, John Elmerdahl; Ngowi, Helena A

    2014-01-01

    Escherichia coli strains such as Shiga toxin-producing E. coli (STEC), enteropathogenic E. coli, enterotoxigenic, attaching, and effacing E. coli, and enteroinvasive E. coli cause diarrhea in humans. Although other serotypes exist, the most commonly reported STEC in outbreaks is O157:H7. A cross-...

  10. Lactobacillus reuteri strains protect epithelial barrier integrity of IPEC-J2 monolayers from the detrimental effect of enterotoxigenic Escherichia coli.

    Science.gov (United States)

    Karimi, Shokoufeh; Jonsson, Hans; Lundh, Torbjörn; Roos, Stefan

    2018-01-01

    Lactobacillus reuteri is an inhabitant of the gastrointestinal (GI) tract of mammals and birds and several strains of this species are known to be effective probiotics. The mechanisms by which L. reuteri confers its health-promoting effects are far from being fully understood, but protection of the mucosal barrier is thought to be important. Leaky gut is a state of abnormal intestinal permeability with implications for the pathophysiology of various gastrointestinal disorders. Enterotoxigenic Escherichia coli (ETEC) can invade the intestinal mucosa and induce changes in barrier function by producing enterotoxin or by direct invasion of the intestinal epithelium. Our hypothesis was that L. reuteri can protect the mucosal barrier, and the goal of the study was to challenge this hypothesis by monitoring the protective effect of L. reuteri strains on epithelial dysfunction caused by ETEC. Using an infection model based on the porcine intestinal cell line IPEC-J2, it was demonstrated that pretreatment of the cells with human-derived L. reuteri strains (ATCC PTA 6475, DSM 17938 and 1563F) and a rat strain (R2LC) reduced the detrimental effect of ETEC in a dose-dependent manner, as monitored by permeability of FITC-dextran and transepithelial electrical resistance (TEER). Moreover, the results revealed that ETEC upregulated proinflammatory cytokines IL-6 and TNFα and decreased expression of the shorter isoform of ZO-1 (187 kDa) and E-cadherin. In contrast, pretreatment with L. reuteri DSM 17938 and 1563F downregulated expression of IL-6 and TNFα, and led to an increase in production of the longer isoform of ZO-1 (195 kDa) and maintained E-cadherin expression. Interestingly, expression of ZO-1 (187 kDa) was preserved only when the infected cells were pretreated with strain 1563F. These findings demonstrate that L. reuteri strains exert a protective effect against ETEC-induced mucosal integrity disruption. © 2018 The Authors. Physiological Reports published by

  11. The first 30 years of Shiga toxin-producing Escherichia coli in cattle production: Incidence, preharvest ecology, and management

    Science.gov (United States)

    Of the 700 serotypes of Escherichia coli, most are commensal; however, some range from mildly to highly pathogenic and can cause death. The disease-causing enterovirulent E. coli are classified as: Enterotoxigenic E. coli (ETEC), Enteropathogenic E. coli (EPEC), Enteroinvasive E. coli (EIEC), and ...

  12. Reduction of verotoxigenic Escherichia coli in production of fermented sausages.

    Science.gov (United States)

    Holck, Askild L; Axelsson, Lars; Rode, Tone Mari; Høy, Martin; Måge, Ingrid; Alvseike, Ole; L'abée-Lund, Trine M; Omer, Mohamed K; Granum, Per Einar; Heir, Even

    2011-11-01

    After a number of foodborne outbreaks of verotoxigenic Escherichia coli involving fermented sausages, some countries have imposed regulations on sausage production. For example, the US Food Safety and Inspection Service requires a 5 log(10) reduction of E. coli in fermented products. Such regulations have led to a number of studies on the inactivation of E. coli in fermented sausages by changing processing and post-processing conditions. Several factors influence the survival of E. coli such as pre-treatment of the meat, amount of NaCl, nitrite and lactic acid, water activity, pH, choice of starter cultures and addition of antimicrobial compounds. Also process variables like fermentation temperature and storage time play important roles. Though a large variety of different production processes of sausages exist, generally the reduction of E. coli caused by production is in the range 1-2 log(10). In many cases this may not be enough to ensure microbial food safety. By optimising ingredients and process parameters it is possible to increase E. coli reduction to some extent, but in some cases still other post process treatments may be required. Such treatments may be storage at ambient temperatures, specific heat treatments, high pressure processing or irradiation. HACCP analyses have identified the quality of the raw materials, low temperature in the batter when preparing the sausages and a rapid pH drop during fermentation as critical control points in sausage production. This review summarises the literature on the reduction verotoxigenic E. coli in production of fermented sausages. Copyright © 2011 Elsevier Ltd. All rights reserved.

  13. Toxicity mechanism of carbon nanotubes on Escherichia coli

    Energy Technology Data Exchange (ETDEWEB)

    Young, Yu-Fu [Department of Materials Science and Engineering, National Tsing-Hua University, No. 101, Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan (China); Lee, Hui-Ju [Department of Life Science, National Tsing-Hua University, No. 101, Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan (China); Shen, Yi-Shan; Tseng, Shih-Hao; Lee, Chi-Young [Department of Materials Science and Engineering, National Tsing-Hua University, No. 101, Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan (China); Tai, Nyan-Hwa, E-mail: nhtai@mx.nthu.edu.tw [Department of Materials Science and Engineering, National Tsing-Hua University, No. 101, Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan (China); Chang, Hwan-You, E-mail: hychang@mx.nthu.edu.tw [Department of Life Science, National Tsing-Hua University, No. 101, Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan (China)

    2012-05-15

    Highlights: Black-Right-Pointing-Pointer F-MWCNTs possess higher antibiotic performance than that of the F-SWCNTs. Black-Right-Pointing-Pointer E. coli cells were pierced when incubated with F-MWCNTs and trapped when incubated with F-SWCNTs. Black-Right-Pointing-Pointer The rigidity and moment of CNTs play important role on the antibiotic effect. - Abstract: The influences of carbon nanomaterials on bacteria were investigated using three types of dispersed and functionalized carbon nanomaterials (F-CNMs), viz. functionalized carbon nanopowder (F-CNP), functionalized single-walled carbon nanotubes (F-SWCNTs), and functionalized multi-walled carbon nanotubes (F-MWCNTs). F-CNMs with different aspect ratios were used to study the influence of material configuration on the viability of Escherichia coli (E. coli). Although these materials were functionalized to improve their dispersibility, the original morphologies and chemical properties of the materials were maintained. Traditional bacteria quantitative plating analysis was conducted, and the results of which revealed that the F-CNP and the F-SWCNTs showed a less significant effect on the viability of E. coli, while the F-MWCNTs obviously inhibited cell viability. A Fourier transform infrared spectroscopy and a scanning electron microscopy were used to verify the functionalization of the F-CNMs and to examine the interaction of F-CNMs with E. coli, respectively; in addition, we adopted chemiluminescence assays to measure the concentration of adenosine triphosphate (ATP) released from the damaged cells. The results showed that the ATP of the F-MWCNTs sample is two-fold higher than that of the control, indicating direct piercing of E. coli by F-MWCNTs leads to bacteria death. Furthermore, F-SWCNTs were concluded to have less influence on the viability of E. coli because ultra-long F-SWCNTs used in this study performed less rigidity to pierce the cells.

  14. Toxicity mechanism of carbon nanotubes on Escherichia coli

    International Nuclear Information System (INIS)

    Young, Yu-Fu; Lee, Hui-Ju; Shen, Yi-Shan; Tseng, Shih-Hao; Lee, Chi-Young; Tai, Nyan-Hwa; Chang, Hwan-You

    2012-01-01

    Highlights: ► F-MWCNTs possess higher antibiotic performance than that of the F-SWCNTs. ► E. coli cells were pierced when incubated with F-MWCNTs and trapped when incubated with F-SWCNTs. ► The rigidity and moment of CNTs play important role on the antibiotic effect. - Abstract: The influences of carbon nanomaterials on bacteria were investigated using three types of dispersed and functionalized carbon nanomaterials (F-CNMs), viz. functionalized carbon nanopowder (F-CNP), functionalized single-walled carbon nanotubes (F-SWCNTs), and functionalized multi-walled carbon nanotubes (F-MWCNTs). F-CNMs with different aspect ratios were used to study the influence of material configuration on the viability of Escherichia coli (E. coli). Although these materials were functionalized to improve their dispersibility, the original morphologies and chemical properties of the materials were maintained. Traditional bacteria quantitative plating analysis was conducted, and the results of which revealed that the F-CNP and the F-SWCNTs showed a less significant effect on the viability of E. coli, while the F-MWCNTs obviously inhibited cell viability. A Fourier transform infrared spectroscopy and a scanning electron microscopy were used to verify the functionalization of the F-CNMs and to examine the interaction of F-CNMs with E. coli, respectively; in addition, we adopted chemiluminescence assays to measure the concentration of adenosine triphosphate (ATP) released from the damaged cells. The results showed that the ATP of the F-MWCNTs sample is two-fold higher than that of the control, indicating direct piercing of E. coli by F-MWCNTs leads to bacteria death. Furthermore, F-SWCNTs were concluded to have less influence on the viability of E. coli because ultra-long F-SWCNTs used in this study performed less rigidity to pierce the cells.

  15. Attachment of Escherichia coli and enterococci to particles in runoff.

    Science.gov (United States)

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

    2010-01-01

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

  16. Escherichia coli ST131, an Intriguing Clonal Group

    Science.gov (United States)

    Bertrand, Xavier; Madec, Jean-Yves

    2014-01-01

    SUMMARY In 2008, a previously unknown Escherichia coli clonal group, sequence type 131 (ST131), was identified on three continents. Today, ST131 is the predominant E. coli lineage among extraintestinal pathogenic E. coli (ExPEC) isolates worldwide. Retrospective studies have suggested that it may originally have risen to prominence as early as 2003. Unlike other classical group B2 ExPEC isolates, ST131 isolates are commonly reported to produce extended-spectrum β-lactamases, such as CTX-M-15, and almost all are resistant to fluoroquinolones. Moreover, ST131 E. coli isolates are considered to be truly pathogenic, due to the spectrum of infections they cause in both community and hospital settings and the large number of virulence-associated genes they contain. ST131 isolates therefore seem to contradict the widely held view that high levels of antimicrobial resistance are necessarily associated with a fitness cost leading to a decrease in pathogenesis. Six years after the first description of E. coli ST131, this review outlines the principal traits of ST131 clonal group isolates, based on the growing body of published data, and highlights what is currently known and what we need to find out to provide public health authorities with better information to help combat ST131. PMID:24982321

  17. Recent Advances in Understanding Enteric Pathogenic Escherichia coli

    Science.gov (United States)

    Croxen, Matthew A.; Law, Robyn J.; Scholz, Roland; Keeney, Kristie M.; Wlodarska, Marta

    2013-01-01

    SUMMARY Although Escherichia coli can be an innocuous resident of the gastrointestinal tract, it also has the pathogenic capacity to cause significant diarrheal and extraintestinal diseases. Pathogenic variants of E. coli (pathovars or pathotypes) cause much morbidity and mortality worldwide. Consequently, pathogenic E. coli is widely studied in humans, animals, food, and the environment. While there are many common features that these pathotypes employ to colonize the intestinal mucosa and cause disease, the course, onset, and complications vary significantly. Outbreaks are common in developed and developing countries, and they sometimes have fatal consequences. Many of these pathotypes are a major public health concern as they have low infectious doses and are transmitted through ubiquitous mediums, including food and water. The seriousness of pathogenic E. coli is exemplified by dedicated national and international surveillance programs that monitor and track outbreaks; unfortunately, this surveillance is often lacking in developing countries. While not all pathotypes carry the same public health profile, they all carry an enormous potential to cause disease and continue to present challenges to human health. This comprehensive review highlights recent advances in our understanding of the intestinal pathotypes of E. coli. PMID:24092857

  18. Pulsed-Plasma Disinfection of Water Containing Escherichia coli

    Science.gov (United States)

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

    2007-03-01

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

  19. Inactivation and Gene Expression of a Virulent WastewaterEscherichia coliStrain and the Nonvirulent CommensalEscherichia coliDSM1103 Strain upon Solar Irradiation

    KAUST Repository

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

    2017-01-01

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

  20. 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.