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Sample records for o157 strains isolated

  1. Determination of adhesin gene sequences in, and biofilm formation by, O157 and non-O157 Shiga toxin-producing Escherichia coli strains isolated from different sources.

    PubMed

    Biscola, Franciele Tafarello; Abe, Cecilia Mari; Guth, Beatriz Ernestina Cabilio

    2011-04-01

    Biofilm formation by Shiga toxin-producing Escherichia coli (STEC) has been associated with the expression of different adhesins (type 1 fimbria, curli, Ag43, Cah, and EhaA). In this study, biofilm formation and the presence of adhesin-related gene sequences were determined by PCR in 18 O157 strains and 33 non-O157 strains isolated from different sources (human, animal, food, and water). The expression of different adhesins was also assessed by reverse transcription-PCR (RT-PCR), Congo red agar plates, and mannose-sensitive hemagglutination (MSHA) assay. Biofilm formation occurred in 5/18 (28%) O157 STEC strains and 17/33 (51%) non-O157 STEC strains from different serotypes and sources, when the assays were performed at 28°C for 48 h. Among the non-O157 biofilm-producing isolates, 12/17 (71%) expressed type 1 fimbriae and 11/17 (65%) expressed curli and produced cellulose, while 8/17 (47%) were considered to be Ag43(+) by RT-PCR. Among O157 strains, a close correlation was observed between biofilm formation and expression of curli and cellulose. In non-O157 strains, it seems that, in addition to the presence of curli, the ability to form biofilm is associated with the presence of other factors such as type 1 fimbriae and autotransporter proteins, which may contribute to the persistence of these organisms in the environment. PMID:21317257

  2. Characterization of Escherichia coli O157:H7 Strains Isolated from Supershedding Cattle

    PubMed Central

    Ahmed, Rafiq; Chase-Topping, Margo; Kalchayanand, Norasak; Schmidt, John W.; Bono, James L.

    2013-01-01

    Previous reports have indicated that a small proportion of cattle shedding high levels of Escherichia coli O157:H7 is the main source for transmission of this organism between animals. Cattle achieving a fecal shedding status of 104 CFU of E. coli O157:H7/gram or greater are now referred to as supershedders. The aim of this study was to investigate the contribution of E. coli O157:H7 strain type to supershedding and to determine if supershedding was restricted to a specific set of E. coli O157:H7 strains. Fecal swabs (n = 5,086) were collected from cattle at feedlots or during harvest. Supershedders constituted 2.0% of the bovine population tested. Supershedder isolates were characterized by pulsed-field gel electrophoresis (PFGE), phage typing, lineage-specific polymorphism assay (LSPA), Stx-associated bacteriophage insertion (SBI) site determination, and variant analysis of Shiga toxin, tir, and antiterminator Q genes. Isolates representing 52 unique PFGE patterns, 19 phage types, and 12 SBI clusters were obtained from supershedding cattle, indicating that there is no clustering to E. coli O157:H7 genotypes responsible for supershedding. While being isolated directly from cattle, this strain set tended to have higher frequencies of traits associated with human clinical isolates than previously collected bovine isolates with respect to lineage and tir allele, but not for SBI cluster and Q type. We conclude that no exclusive genotype was identified that was common to all supershedder isolates. PMID:23645203

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

    PubMed

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

    2016-02-01

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

  4. Characterization of non-Shiga-toxin-producing Escherichia coli O157 strains isolated from dogs.

    PubMed

    Bentancor, A; Vilte, D A; Rumi, M V; Carbonari, C C; Chinen, I; Larzábal, M; Cataldi, A; Mercado, E C

    2010-01-01

    Shiga toxin-negative Escherichia coli O157 strains of various H types have been associated with diarrhea in children and are considered potentially pathogenic for humans. In this study, we describe non-Shiga toxin-producing E. coli O157 E. coli strains previously obtained from dogs in Argentina. Different E. coli phylogenetic lineages corresponding to flagellar types H16, H29 and H45 were identified. E. coli serotypes O157:H16 and O157:H45 contained intimin subtypes epsilon and alpha 1, respectively. Serotype O157:H45 carried the bfp gene encoding the bundle-forming pilus. Localized adherence-like patterns to HEp-2 cells were observed in O157:H16 strains, while O157:H45 adhered in a typical localized pattern. A total of eight different XbaI-pulse field electrophoresis patterns with more than 74 % similarity were identified among the nine E. coli O157:H16 strains. Our data emphasized the fact that dogs may harbor human pathogenic E. coli O157 which do not correspond to Shiga toxin-producing strains and whose potential human health hazard should not be underestimated. PMID:20461294

  5. Molecular Profiling of Escherichia coli O157:H7 and Non-O157 Strains Isolated from Humans and Cattle in Alberta, Canada

    PubMed Central

    Li, Vincent; Fach, Patrick; Delannoy, Sabine; Malejczyk, Katarzyna; Patterson-Fortin, Laura; Poon, Alan; King, Robin; Simmonds, Kimberley; Scott, Allison N.; Lee, Mao-Cheng

    2014-01-01

    Virulence markers in Shiga toxin-producing Escherichia coli (STEC) and their association with diseases remain largely unknown. This study determines the importance of 44 genetic markers for STEC (O157 and non-O157) from human clinical cases and their correlation to disease outcome. STEC isolated from a cattle surveillance program were also included. The virulence genes tested were present in almost all O157:H7 isolates but highly variable in non-O157 STEC isolates. Patient age was a significant determinant of clinical outcome. PMID:25540392

  6. Complete Genome Sequence of an Escherichia coli O157:H7 Strain Isolated from a Super-Shedder Steer

    PubMed Central

    Teng, Lin; Ginn, Amber; Jeon, Soojin; Kang, Minyoung

    2016-01-01

    We report here the complete genome sequence of Escherichia coli O157:H7 strain JEONG-1266 isolated from a super- shedder steer in northwest Florida. Cattle are considered a primary reservoir of E. coli O157:H7, and those cattle that excrete this pathogen in their feces at levels ≥104 CFU/g are known as super-shedders. PMID:27056233

  7. Biofilm formation and sanitizer resistance of Escherichia coli O157:H7 strains isolated from "high event period" meat contamination.

    PubMed

    Wang, Rong; Kalchayanand, Norasak; King, David A; Luedtke, Brandon E; Bosilevac, Joseph M; Arthur, Terrance M

    2014-11-01

    In the meat industry, a "high event period" (HEP) is defined as a time period during which commercial meat plants experience a higher than usual rate of Escherichia coli O157:H7 contamination. Genetic analysis indicated that within a HEP, most of the E. coli O157:H7 strains belong to a singular dominant strain type. This was in disagreement with the current beef contamination model stating that contamination occurs when incoming pathogen load on animal hides, which consists of diverse strain types of E. coli O157:H7, exceeds the intervention capacity. Thus, we hypothesize that the HEP contamination may be due to certain in-plant colonized E. coli O157:H7 strains that are better able to survive sanitization through biofilm formation. To test our hypothesis, a collection of 45 E. coli O157:H7 strains isolated from HEP beef contamination incidents and a panel of 47 E. coli O157:H7 strains of diverse genetic backgrounds were compared for biofilm formation and sanitizer resistance. Biofilm formation was tested on 96-well polystyrene plates for 1 to 6 days. Biofilm cell survival and recovery growth after sanitization were compared between the two strain collections using common sanitizers, including quaternary ammonium chloride, chlorine, and sodium chlorite. No difference in "early stage" biofilms was observed between the two strain collections after incubation at 22 to 25°C for 1 or 2 days. However, the HEP strains demonstrated significantly higher potency of "mature" biofilm formation after incubation for 4 to 6 days. Biofilms of the HEP strains also exhibited significantly stronger resistance to sanitization. These data suggest that biofilm formation and sanitization resistance could have a role in HEP beef contamination by E. coli O157:H7, which highlights the importance of proper and complete sanitization of food contact surfaces and food processing equipment in commercial meat plants. PMID:25364934

  8. Escherichia coli O157:H7 strains isolated from environmental sources differ significantly in acid resistance compared to human outbreak strains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A number of studies on the influence of acid on Escherichia coli O157:H7 have shown considerable strain differences, but limited information has been reported to compare the acid resistance based on the different sources of E. coli O157:H7 isolates. The purpose of this study was to determine the sur...

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

    PubMed Central

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

    2014-01-01

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

  10. Draft Genome Sequence of Shiga Toxin-Negative Escherichia coli O157:H7 Strain C1-057, Isolated from Feedlot Cattle

    PubMed Central

    Carlson, Brandon; Geornaras, Ifigenia; Woerner, Dale; Sofos, John; Belk, Keith

    2016-01-01

    Escherichia coli O157:H7 is one of the major foodborne pathogens in the United States. We isolated a variant Shiga toxin-negative E. coli O157:H7 strain from feedlot cattle. We report here the draft genome sequence of this isolate, consisting of a chromosome of ~4.8 Mb and two plasmids of ~96 kb and ~14 kb. PMID:26941140

  11. Draft Genome Sequence of Shiga Toxin-Negative Escherichia coli O157:H7 Strain C1-057, Isolated from Feedlot Cattle.

    PubMed

    Yang, Hua; Carlson, Brandon; Geornaras, Ifigenia; Woerner, Dale; Sofos, John; Belk, Keith

    2016-01-01

    Escherichia coli O157:H7 is one of the major foodborne pathogens in the United States. We isolated a variant Shiga toxin-negative E. coli O157:H7 strain from feedlot cattle. We report here the draft genome sequence of this isolate, consisting of a chromosome of ~4.8 Mb and two plasmids of ~96 kb and ~14 kb. PMID:26941140

  12. Verotoxigenic Escherichia coli O157:H7 from Swedish cattle; isolates from prevalence studies versus strains linked to human infections - A retrospective study

    PubMed Central

    2010-01-01

    Background Several cases of human infection caused by verotoxin-producing Escherichia coli (VTEC) O157:H7 in Sweden have been connected with cattle farm visits. Between 1996 and 2002, 18 farms were classified as the source of human cases with isolation of EHEC (Enterohaemorrhagic Escherichia coli) after VTEC O157:H7 had been isolated from cattle on those farms. Results Characterization by phage typing and molecular methods of the strains isolated from these 18 farms, including PCR for virulence genes (vtx1, vtx2 and variants thereof, eaeA and EHEC-hlyA) and Pulsed-Field Gel Electrophoresis (PFGE), demonstrated a cluster of very similar strains from 16 farms. All were of phage type 4, carried the genes encoding the verotoxins VT2 and VT2c, intimin, EHEC-haemolysin and flagellin H7 as shown by PCR, and had identical or very similar PFGE patterns. When analysing strains in a prevalence study of VTEC O157:H7 from cattle at slaughter as well as from an on-farm prevalence study of dairy cattle, using the same typing methods, a rather wide variation was observed among the isolated VTEC O157:H7 strains. Conclusions In Sweden, a limited group of genetically similar and highly pathogenic VTEC O157:H7 strains seem to predominate in direct or indirect transmission from cattle to man. PMID:20113494

  13. Clinical Isolates of Non-O157 Shiga Toxin-Producing Escherichia coli: Serotypes, Virulence Characteristics, and Molecular Profiles of Strains of the Same Serotype

    PubMed Central

    Eklund, Marjut; Scheutz, Flemming; Siitonen, Anja

    2001-01-01

    All human Shiga toxin-producing Escherichia coli (STEC) non-O157 strains (n = 56) isolated in Finland from 1990 to August 2000 were characterized for the O:H serotype, stx1 and stx2 genes, production of enterohemolysin, and sensitivity to 12 antimicrobial agents. Strains of the same serotype were genotyped by pulsed-field gel electrophoresis (PFGE) after XbaI restriction of total DNA. The 56 non-O157 isolates belonged to 29 serotypes. Two of the serotypes (O102:H7 and OX181:H49) have not previously been described as being associated with STEC infections in humans or isolated from animals. Thirty-four strains (61%) within seven serotypes (O103:H2 [14 isolates], O26:H11 [6 isolates], O145:H28 [4 isolates], O145:HNM [3 isolates], O15:HNM [3 isolates], OX174:H21 [2 isolates], and O Rough:HNM [2 isolates]) were represented by more than one isolate. Of these strains, O103:H2 isolates were divided into seven, O26:H11 isolates were divided into four, and the rest within a serotype were divided into two genotypes in PFGE. In PCR, 31 (55%) of the 56 strains were positive for the stx2 gene only and 24 strains (43%) were positive for stx1 only. One strain (O43:H2) carried both stx1 and stx2. Forty-two strains (75%) produced enterohemolysin, and 39 strains (70%) possessed the eae gene. Of the latter 39 strains, 36 (92%) were enterohemolytic, whereas only 6 (35%) of the 17 isolates lacking the eae gene were enterohemolytic (P < 0.001). The majority of the strains (44 strains, 79%) were sensitive to all 12 antimicrobials tested. Of the 56 strains, 20 (36%) were associated with small family outbreaks in nine families and 14 (25%) were associated with recent travel abroad. PMID:11473999

  14. Characterization of E. coli O157:H7 strains isolated from “High Event Period” beef trim contamination

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Introduction: A “High Event Period” (HEP) is defined as a time period in which commercial plants experience a higher than usual rate of E. coli O157:H7 contamination of beef trims. Our previous studies suggested that instead of being a direct result of bacteria on animal hides, in-plant biofilm for...

  15. [Isolation of enterohemorrhagic Escherichia coli (O157:H7) by an immunomagnetic separation method].

    PubMed

    Asai, Y; Murase, T; Osawa, R; Okitsu, T; Suzuki, R; Sata, S; Yamai, S; Wada, A; Tamura, K; Watanabe, H

    1997-01-01

    Three sporadic cases of enterohemorrhagic Escherichia coli (EHEC) O157 infection which occurred in Kanagawa in 1996 were investigated. In an attempt to determine sources of the infection, a novel method of immunomagnetic separation (IMS) was employed to isolate the bacterium from feces, foods, and other associated items. In the first case, strains of EHEC O157:H7 producing Vero toxin (VT) 2 were isolated from both feces of the patient and suspected food (cattle liver) kept at a restaurant, and the strains were found to be genotypically identical through an analysis of pulsed-field gel electrophoresis (PFGE). Subsequent investigation in the meat processing store, from which the above cattle liver had been retailed to the restaurants revealed that the store was contaminated with EHEC O157:H7 producing both VT1 and VT2. In the second case, a strain isolated from the patient was EHEC O157:H7 producing both VT1 and VT2 while strains isolated from the patient's family (without apparent symptom) and the suspected facility were O137:NM producing VT2. PFGE analysis indicated that the latter two strains were genotypically identical, suggesting that the facility thus contaminated with EHEC O157 caused the infection in question. In the third case, EHEC O157:NM producing VT2 was isolated from 4 out of 7 family members including the patient, and these strains were found to be genotypically identical by subsequent PFGE analysis. Source of the infection was, however, not determined due to lack of suspected food items. In this context, four slaughterhouses in Kanagawa Prefecture were investigated for presence of EHEC O157. As a result, strains of EHEC O157:H7 producing VT1 and VT2 were isolated from the contents of cattle's distal colon and surface of the skinned carcasses. Additional attempt was also made to determine a possibility of river water being contaminated with EHEC O157. The bacterium was, however, not isolated from water samples collected from 4 major rivers in the

  16. Characterization of Shiga Toxigenic Escherichia coli O157 and Non-O157 Isolates from Ruminant Feces in Malaysia

    PubMed Central

    Perera, Asanthi; Clarke, Charles M.; Dykes, Gary A.; Fegan, Narelle

    2015-01-01

    Shiga toxigenic Escherichia coli (STEC) O157 and several other serogroups of non-O157 STEC are causative agents of severe disease in humans world-wide. The present study was conducted to characterize STEC O157 and non-O157 serogroups O26, O103, O111, O121, O45, and O145 in ruminants in Malaysia. A total of 136 ruminant feces samples were collected from 6 different farms in Peninsular Malaysia. Immunomagnetic beads were used to isolate E. coli O157 and non-O157 serogroups, while PCR was used for the detection and subtyping of STEC isolates. STEC O157:H7 was isolated from 6 (4%) feces samples and all isolates obtained carried stx2c,  eaeA-γ1, and ehxA. Non-O157 STEC was isolated from 2 (1.5%) feces samples with one isolate carrying stx1a, stx2a, stx2c, and ehxA and the other carrying stx1a alone. The presence of STEC O157 and non-O157 in a small percentage of ruminants in this study together with their virulence characteristics suggests that they may have limited impact on public health. PMID:26539484

  17. Genetic Relatedness and Novel Sequence Types of Non-O157 Shiga Toxin-Producing Escherichia coli Strains Isolated in Argentina

    PubMed Central

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

    2016-01-01

    Shiga toxin-producing Escherichia coli (STEC) is a foodborne pathogen responsible for severe disease in humans such as hemolytic uremic syndrome (HUS) and cattle, the principal reservoir. Identification of the clones/lineages is important as several characteristics, among them propensity to cause disease varies with STEC phylogenetic origin. At present, we do not know what STEC clones, especially of non-O157:H7, are circulating in Argentina. To fill this knowledge gap we assessed the genetic diversity of STEC strains isolated in Argentina from various sources, mostly cattle and food, using multilocus sequence typing (MLST). Our objectives were to determine the phylogenetic relationships among strains and to compare them with strains from different geographic origins, especially with those from clinical human cases, in order to evaluate their potential health risk. A total of 59 STEC isolates from 41 serotypes were characterized by MLST. Analysis using EcMLST database identified 38 sequence types (ST), 17 (45%) of which were new STs detected in 18 serotypes. Fifteen out of 38 STs identified were grouped into 11 clonal groups (CGs) and, 23 not grouped in any of the defined CGs. Different STs were found in the same serotype. Results highlighted a high degree of phylogenetic heterogeneity among Argentinean strains and they showed that several cattle and food isolates belonged to the same STs that are commonly associated with clinical human cases in several geographical areas. STEC is a significant public health concern. Argentina has the highest incidence of HUS in the world and this study provides the first data about which STEC clones are circulating. Data showed that most of them might pose a serious zoonotic risk and this information is important for developing public health initiatives. However, the actual potential risk will be defined by the virulence profiles, which may differ among isolates belonging to the same ST.

  18. Genetic Relatedness and Novel Sequence Types of Non-O157 Shiga Toxin-Producing Escherichia coli Strains Isolated in Argentina.

    PubMed

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

    2016-01-01

    Shiga toxin-producing Escherichia coli (STEC) is a foodborne pathogen responsible for severe disease in humans such as hemolytic uremic syndrome (HUS) and cattle, the principal reservoir. Identification of the clones/lineages is important as several characteristics, among them propensity to cause disease varies with STEC phylogenetic origin. At present, we do not know what STEC clones, especially of non-O157:H7, are circulating in Argentina. To fill this knowledge gap we assessed the genetic diversity of STEC strains isolated in Argentina from various sources, mostly cattle and food, using multilocus sequence typing (MLST). Our objectives were to determine the phylogenetic relationships among strains and to compare them with strains from different geographic origins, especially with those from clinical human cases, in order to evaluate their potential health risk. A total of 59 STEC isolates from 41 serotypes were characterized by MLST. Analysis using EcMLST database identified 38 sequence types (ST), 17 (45%) of which were new STs detected in 18 serotypes. Fifteen out of 38 STs identified were grouped into 11 clonal groups (CGs) and, 23 not grouped in any of the defined CGs. Different STs were found in the same serotype. Results highlighted a high degree of phylogenetic heterogeneity among Argentinean strains and they showed that several cattle and food isolates belonged to the same STs that are commonly associated with clinical human cases in several geographical areas. STEC is a significant public health concern. Argentina has the highest incidence of HUS in the world and this study provides the first data about which STEC clones are circulating. Data showed that most of them might pose a serious zoonotic risk and this information is important for developing public health initiatives. However, the actual potential risk will be defined by the virulence profiles, which may differ among isolates belonging to the same ST. PMID:27625995

  19. Escherichia coli O157:H7 and Other E. coli Strains Share Physiological Properties Associated with Intestinal Colonization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Escherichia coli isolates(72 commensal and 10 O157:H7 isolates) were compared with regard to physiological and growth parameters related to their ability to survive and persist in the gastrointestinal tract and found to be similar. We propose that in nonhuman hosts E. coli O157:H7 strains function ...

  20. Persistence of Escherichia coli O157 and non-O157 strains in agricultural soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Shiga toxin producing Escherichia coli O157 and non-O157 serogroups are known to cause serious diseases in human. However, research on the persistence of E. coli non-O157 serogroups in preharvest environment is limited. In the current study, we compared the survival behavior of E. coli O157 to that ...

  1. [Isolation and characterization of Escherichia coli O157 in bovine meat products and cattle in the province of Tucuman].

    PubMed

    Jure, María A; Condorí, Marina S; Pérez Terrazzino, Gabriela; Catalán, Mariana G; López Campo, Alejandro; Zolezzi, Gisella; Chinen, Isabel; Rivas, Marta; Castillo, Marta

    2015-01-01

    Escherichia coli O157 is an emergent pathogen associated with diarrhea, hemorrhagic colitis and hemolytic uremic syndrome. Meat products constitute an important transmission source of this microorganism. The aims of this study were to characterize E. coli O157 isolated from cattle and meat products collected from abattoirs and retail stores, to establish the clonal relatedness among regional isolates and to compare them with those in the national database. Between 2004 and 2013, 169 minced meat, 35 sausage and 216 carcass samples were analyzed. Thirteen E. coli O157 isolates were identified; 6 of which were O157:H7 and characterized as stx2c(vh-a)/eae/ehxA (n = 5) and stx2/eae/ehxA (n = 1). The 7 remaining isolates were non-toxigenic E. coli strains, and serotyped as O157:NT (n = 4), O157:NM (n = 1), O157:ND (n = 1) and O157:H16 (n = 1). The strains yielded different XbaI-PFGE patterns. Compared to the E. coli O157 isolates in the National Database, none of these patterns have been previously detected in strains of different origin in Argentina. PMID:26026230

  2. Escherichia coli O157:H7 strains isolated from “High Event Period” beef contamination have strong biofilm forming ability and low sanitizer susceptibility which are associated with high pO157 plasmid copy number

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the meat industry, a “High Event Period” (HEP) is defined as a time period when beef processing establishments experience an increased occurrence of product contamination by E. coli O157:H7. Our previous studies suggested that bacterial biofilm formation and sanitizer resistance might contribute...

  3. Genetically Marked Strains of Shiga Toxin-Producing O157:H7 and Non-O157 Escherichia coli: Tools for Detection and Modeling.

    PubMed

    Paoli, George C; Wijey, Chandi; Uhlich, Gaylen A

    2015-05-01

    Shiga toxin-producing E. coli (STEC) is an important group of foodborne pathogens in the United States and worldwide. Nearly half of STEC-induced diarrheal disease in the United States is caused by serotype O157:H7, while non-O157 STEC account for the remaining illnesses. Thus, the U.S. Department of Agriculture (USDA) Food Safety and Inspection Service has instituted regulatory testing of beef products and has a zero-tolerance policy for regulatory samples that test positive for STEC O157:H7 and six other non-O157 STEC (serogroups O26, O45, O103, O111, O121, and O145). In this study, positive control (PC) strains for the detection of STEC O157:H7 and the six USDA-regulated non-O157 STEC were constructed. To ensure that the food testing samples are not cross-contaminated by the PC sample, it is important that the STEC-PC strains are distinguishable from STEC isolated from test samples. The PC strains were constructed by integrating a unique DNA target sequence and a gene for spectinomycin (Sp) resistance into the chromosomes of the seven STEC strains. End-point and real-time PCR assays were developed for the specific detection of the PC strains and were tested using 93 strains of E. coli (38 STEC O157:H7, at least 6 strains of each of the USDA-regulated non-O157 STEC, and 2 commensal E. coli) and 51 strains of other bacteria (30 species from 20 genera). The PCR assays demonstrated high specificity for the unique target sequence. The target sequence was detectable by PCR after 10 culture passages (∼100 generations), demonstrating the stability of the integrated target sequence. In addition, the strains were tested for their potential use in modeling the growth of STEC. Plating the PC strains mixed with ground beef flora on modified rainbow agar containing Sp eliminated the growth of the background flora that grew on modified rainbow agar without Sp. Thus, these strains could be used to enumerate and model the growth of STEC in the presence of foodborne background

  4. Biofilm formation by Shiga toxin–producing Escherichia coli O157:H7 and non-O157 strains and their tolerance to sanitizers commonly used in the food processing environment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Shiga toxin–producing Escherichia coli (STEC) strains are important foodborne pathogens. Among these, E. coli O157:H7 is the most frequently isolated STEC serotype responsible for foodborne diseases. However, the non-O157 serotypes have been associated with serious outbreaks and sporadic diseases as...

  5. Characterization of Shiga Toxin-Producing Escherichia coli O157 Isolates from Bovine Carcasses.

    PubMed

    Fontcuberta, M; Planell, R; Torrents, A; Sabaté, S; Gonzalez, R; Ramoneda, M; de Simón, M

    2016-08-01

    The main purpose of this study was to determine the prevalence of Escherichia coli O157 on bovine carcasses before and after chilling at a large slaughterhouse located in the city of Barcelona, Spain, to assess the effectiveness of dry chilling on reducing E. coli O157 contamination of carcasses. In addition, the study characterized the E. coli O157 strains isolated in terms of virulence factors, antibiotic susceptibility, and their genetic diversity. Individual bovine carcasses were sampled before (n = 300) and after (n = 300) chilling over an 8-month period. Positive samples for E. coli O157 were subjected to virulence screening by PCR (stx1, stx2, and eaeA genes and the fliCH7 gene), antimicrobial susceptibility testing, and molecular typing by pulsed-field gel electrophoresis. A total of 9.7% (29 of 300) of the nonrefrigerated carcasses examined and 2.3% (7 of 300) of the refrigerated carcasses were positive for E. coli O157. All the isolates were serotype O157:H7, 92% (33 of 36) carried the stx1, stx2, and eaeA genes, and 8% (3 of 36) carried the stx2 and eaeA genes. Antimicrobial susceptibility testing showed a high degree of resistance: 29 strains (81%) were resistant to at least 1 antimicrobial of the 12 antimicrobials tested; 69% (25 of 36) were resistant to 4 or more antimicrobials. Molecular typing by pulsed-field gel electrophoresis found a high diversity of genetic types, implying little cross-contamination in the slaughterhouse. This study confirms that E. coli O157:H7 is present on the carcasses slaughtered in Spain, although its prevalence is reduced by the dry chilling process used. The recovered isolates showed potential pathogenesis and a high degree of multidrug resistance, confirming the importance of bovine meat monitoring. PMID:27497130

  6. Differential Persistence of E. coli O157:H7 Strains on Romaine Lettuce Leaves

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Outbreaks associated with leafy greens have focused attention on the persistence of Escherichia coli O157:H7 on produce. Limited information is available on ecological interactions influencing persistence of different E. coli O157:H7 strains on lettuce. Survival of six strains of E. coli O157:H7 i...

  7. Polymorphic amplified typing sequences (PATS) and pulsed-field gel electrophoresis (PFGE) yield comparable results in the strain typing of a diverse set of bovine Escherichia coli O157 isolates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The PCR-based Escherichia coli O157 (O157) strain typing system, Polymorphic Amplified Typing Sequences (PATS), targets insertions-deletions (Indels) and single nucleotide polymorphisms (SNPs) at the XbaI and AvrII(BlnI) restriction enzyme sites, respectively, besides amplifying four known virulenc...

  8. Escherichia coli O157:H7 bacteriophage Φ241 isolated from an industrial cucumber fermentation at high acidity and salinity

    PubMed Central

    Lu, Zhongjing; Breidt, Fred

    2015-01-01

    A novel phage, Φ241, specific for Escherichia coli O157:H7 was isolated from an industrial cucumber fermentation where both acidity (pH ≤ 3.7) and salinity (≥5% NaCl) were high. The phage belongs to the Myoviridae family. Its latent period was 15 min and average burst size was 53 phage particles per infected cell. The phage was able to lyse 48 E. coli O157:H7 strains, but none of the 18 non-O157 strains (including E. coli O104:H7) or the 2 O antigen-negative mutants of O157:H7 strain, 43895Δper (also lacking H7 antigen) and F12 (still expressing H7 antigen). However, the phage was able to lyse a per-complemented strain (43895ΔperComp) which expresses O157 antigen. These results indicated that phage Φ241 is specific for O157 antigen, and E. coli strains lacking O157 antigen were resistant to the phage infection, regardless of the presence or absence of H7 antigen. SDS-PAGE profile revealed at least 13 structural proteins of the phage. The phage DNA was resistant to many commonly used restriction endonucleases, suggesting the presence of modified nucleotides in the phage genome. At the multiplicity of infection of 10, 3, or 0.3, the phage caused a rapid cell lysis within 1 or 2 h, resulting in 3.5- or 4.5-log-unit reduction in cell concentration. The high lytic activity, specificity and tolerance to low pH and high salinity make phage Φ241 a potentially ideal biocontrol agent of E. coli O157:H7 in various foods. To our knowledge, this is the first report on E. coli O157:H7 phage isolated from high acidity and salinity environment. PMID:25741324

  9. Shiga-toxigenic Escherichia coli O157 and non-Shiga-toxigenic Escherichia coli O157 respond differently to culture and isolation from naturally contaminated bovine feces

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We quantified the effects of two immunomagnetic separation (IMS) strategies, two broth enrichment times, and two selective plating media on isolation rates of Shiga-toxigenic Escherichia coli (STEC) O157 and non-STEC O157 from fecal specimens of naturally infected feedlot cattle. STEC O157 and non-...

  10. Whole-Genome Sequence of Escherichia coli Serotype O157:H7 Strain EDL932 (ATCC 43894)

    PubMed Central

    Paoli, George C.; Chen, Chin-Yi; Cottrell, Bryan J.; Zhang, Xinmin; Yan, Xianghe

    2016-01-01

    The genome sequence of Escherichia coli serotype O157:H7 EDL933, a ground beef isolate from a 1983 hemorrhagic colitis outbreak, is a standard reference for comparative genomic studies of Shiga toxin-producing E. coli strains. Here, we report the genome sequence of a patient stool isolate from that outbreak, strain EDL932. PMID:27417834

  11. Genetically marked strains of Shiga toxin-producing E. coli O157:H7 and non-O157 for detection and modeling

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Introduction: Shiga toxin-producing E. coli (STEC) are among the most important foodborne pathogens in the United States and worldwide. STEC O157:H7 is isolated from about half of all STEC-induced diarrheal disease in North America, while non-O157 STEC account for the remaining isolates. Thus, the U...

  12. REPETITIVE SEQUENCE BASED-PCR PROFILING OF ESCHERICHIA COLI O157 STRAINS FROM BEEF IN SOUTHERN THAILAND.

    PubMed

    Sukhumungoon, Pharanai; Tantadapan, Rujira; Rattanachuay, Pattamarat

    2016-01-01

    Beef and its products are potential vehicles of Escherichia coli O157, the most important serotype implicated in many large outbreaks of diarrheal infection in humans worldwide. There is a need for rapid detection of contaminated food in order to implement appropriate and effective control measures. In this study, repetitive sequence (rep)-PCR, using three different primers, BOXA1R, ERIC2 and (GTG)5, singly and in combinations, were employed to compare the genetic relatedness among E. coli O157 group with other diarrheagenic E. coli strains as controls. Although a combination of BOXA1R + ERIC2 + (GTG)5 primers generated a rep-PCR profile containing the highest number of amplicon bands among the DEC strains tested, dendrogram (at 80% similarity) exhibited the lowest DEC classification of 5 clusters, whereas that from BOXA1R or BOXA1R+ (GTG)5 rep-PCR profiling produced 8 clusters. Nevertheless, focusing E. coli O157 strains were grouped into 4 clusters irrespective of the rep-PCR profiles analyzed, and all 14 but two, PSU60 and PSU132, E. coli O157 strains isolated from beef in southern Thailand during 2012 to 2014 fell into a single cluster. Thus, rep-PCR profiling generated with BOXA1R or BOXA1R + (GTG)5 is sufficient for distinguishing among DEC strains, including E. coli O157 in southern Thailand. PMID:27086425

  13. Isolation of Escherichia coli O157:H7 from foods in Greece.

    PubMed

    Dontorou, C; Papadopoulou, C; Filioussis, G; Economou, V; Apostolou, I; Zakkas, G; Salamoura, A; Kansouzidou, A; Levidiotou, S

    2003-05-15

    The presence of Escherichia coli O157:H7 in various foods of animal origin was surveyed in northwestern Greece. Six hundred samples of unpasteurized cows', ewes' and goats' milk, raw minced meat, uncooked frozen beef hamburgers, sandwiches (containing ham or turkey, mixed vegetable salad with mayonnaise and lettuce), fresh traditional Greek pork sausages and swine intestines appropriate for traditional Greek kokoretsi were assayed for E. coli serogroup O157:H7 using the standard cultural method and the immunomagnetic separation technique. The pathogen was detected in 1 out of 100 (1.0%) samples of ewes' milk, 1 out of 75 (1.3%) fresh sausages and 1 out of 50 (2.0%) swine intestines prepared for kokoretsi. The isolated strains were nonsorbitol fermenters, MUG-negative, O157 agglutinating, verotoxin-producing and carried both VT1 and VT2 genes. The three isolated strains were tested for antibiotic resistance and were found to be susceptible to eight antimicrobial agents (ampicillin, chloramphenicol, kanamycin, nalidixic acid, norfloxacin, streptomycin, sulfamethoxazole-trimethoprim and tetracycline). PMID:12593930

  14. Detection and isolation of non-O157 STECs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Escherichia coli containing one or more of the Shiga toxin genes are characterized as Shiga-toxin producing E. coli (STEC). E. coli serogroup O157 remains the most common STEC in the United States, but epidemiological studies suggest that over 60% of STEC infections are caused by non-O157 STECs, acc...

  15. Antimicrobial resistance in Escherichia coli O157 and non-O157 isolated from feces of domestic farm animals in Culiacan, Mexico

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Antimicrobial resistance in E. coli O157 and non-O157 strains is a matter of increasing concern, and the association with some virulence traits in the same bacteria remains unclear. Inappropriate antimicrobial use in human and animal therapy has been associated with selective pressure in enteric mi...

  16. Strain-Dependent Cellular Immune Responses in Cattle following Escherichia coli O157:H7 Colonization

    PubMed Central

    Corbishley, Alexander; Ahmad, Nur Indah; Hughes, Kirsty; Hutchings, Michael R.; McAteer, Sean P.; Connelley, Timothy K.; Brown, Helen; Gally, David L.

    2014-01-01

    Enterohemorrhagic Escherichia coli (EHEC) O157:H7 causes hemorrhagic diarrhea and potentially fatal renal failure in humans. Ruminants are considered to be the primary reservoir for human infection. Vaccines that reduce shedding in cattle are only partially protective, and their underlying protective mechanisms are unknown. Studies investigating the response of cattle to colonization generally focus on humoral immunity, leaving the role of cellular immunity unclear. To inform future vaccine development, we studied the cellular immune responses of cattle during EHEC O157:H7 colonization. Calves were challenged either with a phage type 21/28 (PT21/28) strain possessing the Shiga toxin 2a (Stx2a) and Stx2c genes or with a PT32 strain possessing the Stx2c gene only. T-helper cell-associated transcripts at the terminal rectum were analyzed by reverse transcription-quantitative PCR (RT-qPCR). Induction of gamma interferon (IFN-γ) and T-bet was observed with peak expression of both genes at 7 days in PT32-challenged calves, while upregulation was delayed, peaking at 21 days, in PT21/28-challenged calves. Cells isolated from gastrointestinal lymph nodes demonstrated antigen-specific proliferation and IFN-γ release in response to type III secreted proteins (T3SPs); however, responsiveness was suppressed in cells isolated from PT32-challenged calves. Lymph node cells showed increased expression of the proliferation marker Ki67 in CD4+ T cells from PT21/28-challenged calves, NK cells from PT32-challenged calves, and CD8+ and γδ T cells from both PT21/28- and PT32-challenged calves following ex vivo restimulation with T3SPs. This study demonstrates that cattle mount cellular immune responses during colonization with EHEC O157:H7, the temporality of which is strain dependent, with further evidence of strain-specific immunomodulation. PMID:25267838

  17. Comparative pathogenicity of Escherichia coli O157 and intimin-negative non-O157 Shiga toxin-producing E coli strains in neonatal pigs.

    PubMed

    Dean-Nystrom, Evelyn A; Melton-Celsa, Angela R; Pohlenz, Joachim F L; Moon, Harley W; O'Brien, Alison D

    2003-11-01

    We compared the pathogenicity of intimin-negative non-O157:H7 Shiga toxin (Stx)-producing Escherichia coli (STEC) O91:H21 and O104:H21 strains with the pathogenicity of intimin-positive O157:H7 and O157:H(-) strains in neonatal pigs. We also examined the role of Stx2d-activatable genes and the large hemolysin-encoding plasmid of O91:H21 strain B2F1 in the pathogenesis of STEC disease in pigs. We found that all E. coli strains that made wild-type levels of Stx caused systemic illness and histological lesions in the brain and intestinal crypts, whereas none of the control Stx-negative E. coli strains evoked comparable central nervous system signs or intestinal lesions. By contrast, the absence of intimin, hemolysin, or motility had little impact on the overall pathogenesis of systemic disease during STEC infection. The most striking differences between pigs inoculated with non-O157 STEC strains and pigs inoculated with O157 STEC strains were the absence of attaching and effacing intestinal lesions in pigs inoculated with non-O157:H7 strains and the apparent association between the level of Stx2d-activatable toxin produced by an STEC strain and the severity of lesions. PMID:14573674

  18. Characterization of Escherichia coli O157:H7 strains from contaminated raw beef trim during "high event periods".

    PubMed

    Arthur, Terrance M; Bono, James L; Kalchayanand, Norasak

    2014-01-01

    The development and implementation of effective antimicrobial interventions by the beef processing industry in the United States have dramatically reduced the incidence of beef trim contamination by Escherichia coli O157:H7. However, individual processing plants still experience sporadic peaks in contamination rates where multiple E. coli O157:H7-positive lots are clustered in a short time frame. These peaks have been referred to as "high event periods" (HEP) of contamination. The results reported here detail the characterization of E. coli O157:H7 isolates from 21 HEP across multiple companies and processing plants to gain insight regarding the mechanisms causing these incidents. Strain genotypes were determined by pulsed-field gel electrophoresis, and isolates were investigated for characteristics linking them to human illness. Through these analyses, it was determined that individual HEP show little to no diversity in strain genotypes. Hence, each HEP has one strain type that makes up most, if not all, of the contamination. This is shown to differ from the genotypic diversity of E. coli O157:H7 found on the hides of cattle entering processing plants. In addition, it was found that a large proportion (81%) of HEP are caused by strain types associated with human illness. These results pose a potential challenge to the current model for finished product contamination during beef processing. PMID:24212567

  19. Carriage of stx2a Differentiates Clinical and Bovine-Biased Strains of Escherichia coli O157

    PubMed Central

    Shringi, Smriti; Schmidt, Carrie; Katherine, Kaya; Brayton, Kelly A.; Hancock, Dale D.; Besser, Thomas E.

    2012-01-01

    Background Shiga toxin (Stx) are cardinal virulence factors of enterohemorrhagic E. coli O157:H7 (EHEC O157). The gene content and genomic insertion sites of Stx-associated bacteriophages differentiate clinical genotypes of EHEC O157 (CG, typical of clinical isolates) from bovine-biased genotypes (BBG, rarely identified among clinical isolates). This project was designed to identify bacteriophage-mediated differences that may affect the virulence of CG and BBG. Methods Stx-associated bacteriophage differences were identified by whole genome optical scans and characterized among >400 EHEC O157 clinical and cattle isolates by PCR. Results Optical restriction maps of BBG strains consistently differed from those of CG strains only in the chromosomal insertion sites of Stx2-associated bacteriophages. Multiplex PCRs (stx1, stx2a, and stx2c as well as Stx-associated bacteriophage - chromosomal insertion site junctions) revealed four CG and three BBG that accounted for >90% of isolates. All BBG contained stx2c and Stx2c-associated bacteriophage – sbcB junctions. All CG contained stx2a and Stx2a-associated bacteriophage junctions in wrbA or argW. Conclusions Presence or absence of stx2a (or another product encoded by the Stx2a-associated bacteriophage) is a parsimonious explanation for differential virulence of BBG and CG, as reflected in the distributions of these genotypes in humans and in the cattle reservoir. PMID:23240045

  20. Comparative Genomic Analysis of Escherichia coli O157:H7 Isolated from Super-Shedder and Low-Shedder Cattle.

    PubMed

    Munns, Krysty D; Zaheer, Rahat; Xu, Yong; Stanford, Kim; Laing, Chad R; Gannon, Victor P J; Selinger, L Brent; McAllister, Tim A

    2016-01-01

    Cattle are the primary reservoir of the foodborne pathogen Escherichia coli O157:H7, with the concentration and frequency of E. coli O157:H7 shedding varying substantially among individual hosts. The term ''super-shedder" has been applied to cattle that shed ≥10(4) cfu E. coli O157:H7/g of feces. Super-shedders have been reported to be responsible for the majority of E. coli O157:H7 shed into the environment. The objective of this study was to determine if there are phenotypic and/or genotypic differences between E. coli O157:H7 isolates obtained from super-shedder compared to low-shedder cattle. From a total of 784 isolates, four were selected from low-shedder steers and six isolates from super-shedder steers (4.01-8.45 log cfu/g feces) for whole genome sequencing. Isolates were phage and clade typed, screened for substrate utilization, pH sensitivity, virulence gene profiles and Stx bacteriophage insertion (SBI) sites. A range of 89-2473 total single nucleotide polymorphisms (SNPs) were identified when sequenced strains were compared to E. coli O157:H7 strain Sakai. More non-synonymous SNP mutations were observed in low-shedder isolates. Pan-genomic and SNPs comparisons did not identify genetic segregation between super-shedder or low-shedder isolates. All super-shedder isolates and 3 of 4 of low-shedder isolates were typed as phage type 14a, SBI cluster 3 and SNP clade 2. Super-shedder isolates displayed increased utilization of galactitol, thymidine and 3-O-β-D-galactopyranosyl-D-arabinose when compared to low-shedder isolates, but no differences in SNPs were observed in genes encoding for proteins involved in the metabolism of these substrates. While genetic traits specific to super-shedder isolates were not identified in this study, differences in the level of gene expression or genes of unknown function may still contribute to some strains of E. coli O157:H7 reaching high densities within bovine feces. PMID:27018858

  1. Comparative Genomic Analysis of Escherichia coli O157:H7 Isolated from Super-Shedder and Low-Shedder Cattle

    PubMed Central

    Munns, Krysty D.; Zaheer, Rahat; Xu, Yong; Stanford, Kim; Laing, Chad R.; Gannon, Victor P. J.; Selinger, L. Brent; McAllister, Tim A.

    2016-01-01

    Cattle are the primary reservoir of the foodborne pathogen Escherichia coli O157:H7, with the concentration and frequency of E. coli O157:H7 shedding varying substantially among individual hosts. The term ‘‘super-shedder” has been applied to cattle that shed ≥104 cfu E. coli O157:H7/g of feces. Super-shedders have been reported to be responsible for the majority of E. coli O157:H7 shed into the environment. The objective of this study was to determine if there are phenotypic and/or genotypic differences between E. coli O157:H7 isolates obtained from super-shedder compared to low-shedder cattle. From a total of 784 isolates, four were selected from low-shedder steers and six isolates from super-shedder steers (4.01–8.45 log cfu/g feces) for whole genome sequencing. Isolates were phage and clade typed, screened for substrate utilization, pH sensitivity, virulence gene profiles and Stx bacteriophage insertion (SBI) sites. A range of 89–2473 total single nucleotide polymorphisms (SNPs) were identified when sequenced strains were compared to E. coli O157:H7 strain Sakai. More non-synonymous SNP mutations were observed in low-shedder isolates. Pan-genomic and SNPs comparisons did not identify genetic segregation between super-shedder or low-shedder isolates. All super-shedder isolates and 3 of 4 of low-shedder isolates were typed as phage type 14a, SBI cluster 3 and SNP clade 2. Super-shedder isolates displayed increased utilization of galactitol, thymidine and 3-O-β-D-galactopyranosyl-D-arabinose when compared to low-shedder isolates, but no differences in SNPs were observed in genes encoding for proteins involved in the metabolism of these substrates. While genetic traits specific to super-shedder isolates were not identified in this study, differences in the level of gene expression or genes of unknown function may still contribute to some strains of E. coli O157:H7 reaching high densities within bovine feces. PMID:27018858

  2. Isolation of Escherichia coli O157:H7 from Intact Colon Fecal Samples of Swine1

    PubMed Central

    Wallace, F. Morgan; Gray, Jeffrey T.; Fratamico, Pina; Fedorka-Cray, Paula J.; Pearce, Rachel A.; Call, Jeffrey E.; Perrine, Richard; Luchansky, John B.

    2003-01-01

    Escherichia coli O157:H7 was recovered from colon fecal samples of pigs. Polymerase chain reaction confirmed two genotypes: isolates harboring the eaeA, stx1, and stx2 genes and isolates harboring the eaeA, stx1, and hly933 genes. We demonstrate that swine in the United States can harbor potentially pathogenic E. coli O157:H7. PMID:12643837

  3. Isolation and molecular characterization of Escherichia coli O157 from broiler and human samples.

    PubMed

    Kalin, Recep; Ongor, Hasan; Cetinkaya, Burhan

    2012-04-01

    There is a lack of information about the role of poultry, specifically chicken, in transmission of Escherichia coli (E. coli) O157 and subsequent human illnesses. This study was therefore aimed at investigating the presence of E. coli O157 and its virulence genes in various samples collected from broiler chickens and humans in Eastern Turkey by culture, immunomagnetic separation (IMS), and polymerase chain reaction (PCR). The genetic relationship between broiler and human isolates was also examined by pulsed-field gel electrophoresis (PFGE). In the PCR analysis of sorbitol-negative isolates, E. coli O157 was identified in 0.1% (1/1000) and 0.4% (4/1000) of the liver and cecum samples of broiler chickens, respectively. On the other hand, none of the carcass samples were determined to be positive for E. coli O157. Overall, the results indicated that 12% (3/25) of the flocks were positive for E. coli O157. The differences between the flocks in terms of the positivity were determined to be statistically significant (p<0.001). Ten (2.7%) of 367 human stool samples were also positive for E. coli O157 in the PCR examination. None of the broiler and human E. coli O157 isolates possessed H7, shigatoxins 1-2, or enterohemolysin genes, whereas all the broiler isolates and one of the human isolates were positive for intimin gene. In the PFGE analysis, a total of eight different profiles (four from broiler and four from human isolates) were observed. However, there were no genetic relationships between broiler and human E. coli O157 isolates. It can be concluded that more detailed studies are needed in poultry to better understand the role of these species in the epidemiology of E. coli 0157 infections in humans. PMID:22304630

  4. Survival of Escherichia coli O157:H7 Isolates in Acetic Acid Solutions is Influenced by the Source of Isolation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Enterohemorrhagic Escherichia coli O157:H7 has been recognized as highly acid resistant in nature because of its low infectious dose and ability to survive in acid foods or to survive in stomach acid. A number of studies on the influence of acid on E. coli O157:H7 have shown considerable strain diff...

  5. Antimicrobial Resistance Profiles in Escherichia coli O157 Isolates from Northern Colorado Dairies.

    PubMed

    McConnel, Craig S; Stenkamp-Strahm, Chloe M; Rao, Sangeeta; Linke, Lyndsey M; Magnuson, Roberta J; Hyatt, Doreene R

    2016-03-01

    Escherichia coli O157 (EcO157) infections can lead to serious disease and death in humans. Although the ecology of EcO157 is complex, ruminant animals serve as an important reservoir for human infection. Dairy cattle are unique because they may be a source of contamination for milk, meat, and manure-fertilized crops. Foodborne dairy pathogens such as EcO157 are of primary importance to public health. Antimicrobial resistance (AMR) is a complex phenomenon that complicates the treatment of serious bacterial infections and is of increasing concern. In the face of recommended use restrictions for antimicrobial agents in livestock operations, current AMR patterns in known foodborne pathogens should be documented. The objective of this study was to document AMR patterns in EcO157 isolates from dairies in northern Colorado using antimicrobial agents commonly found on dairies and representative of medically important antimicrobial drug classes. Seventy-five EcO157 isolates were recovered from three dairies. Six isolates were resistant to at least 1 of the 10 tested antimicrobial agents: four were resistant to streptomycin, sulfisoxazole, and tetracycline; one was resistant to streptomycin and tetracycline; and one was resistant to only tetracycline. All resistant isolates were from a single dairy. Overall, a low prevalence (8%) of AMR was observed among the 75 EcO157 isolates. No significant effects on AMR profiles due to virulence genes, parity, or previous antimicrobial treatments within the current lactation period were detected. The results of this study provide background information for future comparative studies investigating AMR trends. Future studies should include more participating farms and more samples and should control for potential confounding factors of AMR that may underlie individual farm variation. PMID:26939660

  6. Escherichia coli O157:H7 Strains That Persist in Feedlot Cattle Are Genetically Related and Demonstrate an Enhanced Ability To Adhere to Intestinal Epithelial Cells ▿

    PubMed Central

    Carlson, Brandon A.; Nightingale, Kendra K.; Mason, Gary L.; Ruby, John R.; Choat, W. Travis; Loneragan, Guy H.; Smith, Gary C.; Sofos, John N.; Belk, Keith E.

    2009-01-01

    A longitudinal study was conducted to investigate the nature of Escherichia coli O157:H7 colonization of feedlot cattle over the final 100 to 110 days of finishing. Rectal fecal grab samples were collected from an initial sample population of 788 steers every 20 to 22 days and microbiologically analyzed to detect E. coli O157:H7. The identities of presumptive colonies were confirmed using a multiplex PCR assay that screened for gene fragments unique to E. coli O157:H7 (rfbE and fliCh7) and other key virulence genes (eae, stx1, and stx2). Animals were classified as having persistent shedding (PS), transient shedding (TS), or nonshedding (NS) status if they consecutively shed the same E. coli O157:H7 genotype (based on the multiplex PCR profile), exhibited variable E. coli O157 shedding, or never shed morphologically typical E. coli O157, respectively. Overall, 1.0% and 1.4% of steers were classified as PS and NS animals, respectively. Characterization of 132 E. coli O157:H7 isolates from PS and TS animals by pulsed-field gel electrophoresis (PFGE) typing yielded 32 unique PFGE types. One predominant PFGE type accounted for 53% of all isolates characterized and persisted in cattle throughout the study. Isolates belonging to this predominant and persistent PFGE type demonstrated an enhanced (P < 0.0001) ability to adhere to Caco-2 human intestinal epithelial cells compared to isolates belonging to less common PFGE types but exhibited equal virulence expression. Interestingly, the attachment efficacy decreased as the genetic divergence from the predominant and persistent subtype increased. Our data support the hypothesis that certain E. coli O157:H7 strains persist in feedlot cattle, which may be partially explained by an enhanced ability to colonize the intestinal epithelium. PMID:19617387

  7. Use of strain typing to provide evidence for specific interventions in the transmission of VTEC O157 infections.

    PubMed

    Willshaw, G A; Smith, H R; Cheasty, T; O'Brien, S J

    2001-05-21

    Transmission of verocytotoxin (VT)-producing Escherichia coli (VTEC) occurs by three main routes. These comprise food- or water-borne infections, acquisition of disease by direct or indirect contact with animals and person-to-person spread. Phenotypic typing of VTEC belonging to serogroup O157 is achieved by phage typing and identification of VT type. These properties quickly provide evidence for the linkage of human cases and their association to potential sources. DNA-based subtyping methods such as pulsed field gel electrophoresis (PFGE) are generally required to increase discrimination of VTEC O157 strains so that the spread of specific strains can be monitored. Phenotypic and DNA-based methods were used in the investigation of 85 general outbreaks of VTEC O157 infection between 1995 and 1999. Results were used in conjunction with epidemiological data to provide direct or indirect evidence for the likely route of transmission. Detailed strain fingerprinting identified specific food vehicles and reservoirs of infection in animals. Typing supported the implementation of measures to control the spread of infection that included pasteurisation orders, product withdrawal, temporary closure of retail premises and open farms and the introduction of HACCP-based working practices. In outbreaks involving widely distributed foods, DNA-based examination of apparently sporadic isolates with the same phage and VT type as outbreak strains was performed to identify additional potential outbreak cases and estimate the spread of infection. Strain typing was applied in outbreaks in nurseries and other institutions to monitor person-to-person spread, including careers and their families and to assess the involvement of community cases occurring at the same time. Rapid exchange of epidemiological, microbiological and typing data will be increasingly important in investigation of VTEC O157 outbreaks. PMID:11407546

  8. Prevalence of Stx phages in environments of a pig farm and lysogenic infection of the field E. coli O157 isolates with a recombinant converting Phage.

    PubMed

    Yan, Yaxian; Shi, Yibo; Cao, Dongmei; Meng, Xiangpeng; Xia, Luming; Sun, Jianhe

    2011-02-01

    The prevalence and nature of Shiga toxin (Stx)-producing Escherichia coli (STEC) and Stx phage were investigated in 720 swine fecal samples randomly collected from a commercial breeding pig farm in China over a 1-year surveillance period. Eight STEC O157 (1.1%), 33 STEC non-O157 (4.6%), and two stx-negative O157 (0.3%) isolates were identified. Fecal filtrates were screened directly for Stx phages using E. coli K-12 derivative strains MC1061 as indicator, yielding 15 Stx1 and 57 Stx2 phages. One Stx1 and eight Stx2 phages were obtained following norfloxacin induction of the eight field STEC O157 isolates. All Stx1 phages had hexagonal heads with long tails, while Stx2 phages had three different morphologies. Notably, most of field STEC O157 isolates released more free phages and Stx toxin after induction with ciprofloxacin. Furthermore, upon infection with the recombinant phage ΦMin27(Δstx::cat), E. coli laboratory strains produced both lysogenic and lytic phage, whereas two of the eight O157 STEC isolates produced only lysogens. The lysogens from laboratory strains produced infectious particles similar to ΦMin27. Similarly, the lysogens from the STEC O157 isolates released Stx phage too, although free ΦMin27(Δstx::cat) particles were not detected. Collectively, our results reveal that breeding pig farms could be important reservoirs for Stx phages and that residual antibacterial agents may enhance the release of Stx phages and the expression of Stx. PMID:20697714

  9. Selective Enrichment with a Resuscitation Step for Isolation of Freeze-Injured Escherichia coli O157:H7 from Foods

    PubMed Central

    Hara-Kudo, Y.; Ikedo, M.; Kodaka, H.; Nakagawa, H.; Goto, K.; Masuda, T.; Konuma, H.; Kojima, T.; Kumagai, S.

    2000-01-01

    We studied injury of Escherichia coli O157:H7 cells in 11 food items during freeze storage and methods of isolating freeze-injured E. coli O157:H7 cells from foods. Food samples inoculated with E. coli O157:H7 were stored for 16 weeks at −20°C in a freezer. Noninjured and injured cells were counted by using tryptic soy agar and sorbitol MacConkey agar supplemented with cefixime and potassium tellurite. Large populations of E. coli O157:H7 cells were injured in salted cabbage, grated radish, seaweed, and tomato samples. In an experiment to detect E. coli O157:H7 in food samples artificially contaminated with freeze-injured E. coli O157:H7 cells, the organism was recovered most efficiently after the samples were incubated in modified E. coli broth without bile salts at 25°C for 2 h and then selectively enriched at 42°C for 18 h by adding bile salts and novobiocin. Our enrichment method was further evaluated by isolating E. coli O157:H7 from frozen foods inoculated with the organism prior to freezing. Two hours of resuscitation at 25°C in nonselective broth improved recovery of E. coli O157:H7 from frozen grated radishes and strawberries, demonstrating that the resuscitation step is very effective for isolating E. coli O157:H7 from frozen foods contaminated with injured E. coli O157:H7 cells. PMID:10877780

  10. Clade 8 and Clade 6 Strains of Escherichia coli O157:H7 from Cattle in Argentina have Hypervirulent-Like Phenotypes

    PubMed Central

    Amigo, Natalia; Mercado, Elsa; Bentancor, Adriana; Singh, Pallavi; Vilte, Daniel; Gerhardt, Elisabeth; Zotta, Elsa; Ibarra, Cristina; Manning, Shannon D.; Larzábal, Mariano; Cataldi, Angel

    2015-01-01

    The hemolytic uremic syndrome (HUS) whose main causative agent is enterohemorrhagic Escherichia coli (EHEC) O157:H7 is a disease that mainly affects children under 5 years of age. Argentina is the country with the highest incidence of HUS in the world. Cattle are a major reservoir and source of infection with E. coli O157:H7. To date, the epidemiological factors that contribute to its prevalence are poorly understood. Single nucleotide polymorphism (SNP) typing has helped to define nine E. coli O157:H7 clades and the clade 8 strains were associated with most of the cases of severe disease. In this study, eight randomly selected isolates of EHEC O157:H7 from cattle in Argentina were studied as well as two human isolates. Four of them were classified as clade 8 through the screening for 23 SNPs; the two human isolates grouped in this clade as well, while two strains were closely related to strains representing clade 6. To assess the pathogenicity of these strains, we assayed correlates of virulence. Shiga toxin production was determined by an ELISA kit. Four strains were high producers and one of these strains that belonged to a novel genotype showed high verocytotoxic activity in cultured cells. Also, these clade 8 and 6 strains showed high RBC lysis and adherence to epithelial cells. One of the clade 6 strains showed stronger inhibition of normal water absorption than E. coli O157:H7 EDL933 in human colonic explants. In addition, two of the strains showing high levels of Stx2 production and RBC lysis activity were associated with lethality and uremia in a mouse model. Consequently, circulation of such strains in cattle may partially contribute to the high incidence of HUS in Argentina. PMID:26030198

  11. Clade 8 and Clade 6 Strains of Escherichia coli O157:H7 from Cattle in Argentina have Hypervirulent-Like Phenotypes.

    PubMed

    Amigo, Natalia; Mercado, Elsa; Bentancor, Adriana; Singh, Pallavi; Vilte, Daniel; Gerhardt, Elisabeth; Zotta, Elsa; Ibarra, Cristina; Manning, Shannon D; Larzábal, Mariano; Cataldi, Angel

    2015-01-01

    The hemolytic uremic syndrome (HUS) whose main causative agent is enterohemorrhagic Escherichia coli (EHEC) O157:H7 is a disease that mainly affects children under 5 years of age. Argentina is the country with the highest incidence of HUS in the world. Cattle are a major reservoir and source of infection with E. coli O157:H7. To date, the epidemiological factors that contribute to its prevalence are poorly understood. Single nucleotide polymorphism (SNP) typing has helped to define nine E. coli O157:H7 clades and the clade 8 strains were associated with most of the cases of severe disease. In this study, eight randomly selected isolates of EHEC O157:H7 from cattle in Argentina were studied as well as two human isolates. Four of them were classified as clade 8 through the screening for 23 SNPs; the two human isolates grouped in this clade as well, while two strains were closely related to strains representing clade 6. To assess the pathogenicity of these strains, we assayed correlates of virulence. Shiga toxin production was determined by an ELISA kit. Four strains were high producers and one of these strains that belonged to a novel genotype showed high verocytotoxic activity in cultured cells. Also, these clade 8 and 6 strains showed high RBC lysis and adherence to epithelial cells. One of the clade 6 strains showed stronger inhibition of normal water absorption than E. coli O157:H7 EDL933 in human colonic explants. In addition, two of the strains showing high levels of Stx2 production and RBC lysis activity were associated with lethality and uremia in a mouse model. Consequently, circulation of such strains in cattle may partially contribute to the high incidence of HUS in Argentina. PMID:26030198

  12. Human Escherichia coli O157:H7 Genetic Marker in Isolates of Bovine Origin

    PubMed Central

    Abedon, Stephen T.; Takemura, Kaori; Christie, Nicholas P.; Sreevatsan, Srinand

    2004-01-01

    The antiterminator Q gene of bacteriophage 933W (Q933) was identified upstream of the stx2 gene in 90% of human disease–origin Escherichia coli O157:H7 isolates and in 44.5% of bovine isolates. Shiga toxin production was higher in Q933-positive isolates than Q933-negative isolates. This genetic marker may provide a useful molecular tool for epidemiologic studies. PMID:15496255

  13. Strain differences in fitness of Escherichia coli O157:H7 to resist protozoan predation and survival in soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Escherichia coli O157:H7 (EcO157) associated with 2006 spinach outbreak appears to have persisted as the organism was later isolated from environmental samples in the produce production areas of central coast of California. Survival in harsh environments was often linked to the inherent fitness char...

  14. Genetic relationships among pathogenic Escherichia coli of serogroup O157.

    PubMed Central

    Whittam, T S; Wilson, R A

    1988-01-01

    Escherichia coli strains of serotype O157:H7 are a newly described clonal pathogenic form associated with recent outbreaks of hemorrhagic colitis in humans. Although O157 strains of various H types have long been recognized as enterotoxigenic in animals, little is known about how these pathogenic animal strains are related to those of serotype O157:H7. To determine the genetic relatedness of O157:H7 isolates to animal O157 strains, we examined 194 O157 isolates, representing 12 distinct flagellar antigens (H serotypes), obtained from a variety of animal and human infections. To characterize isolates, we assayed allelic variation at 19 enzyme loci by multilocus enzyme electrophoresis. Genotypic comparisons of isolates revealed extensive variation among 33 distinct clonal genotypes that differed, on average, at 44% of the enzyme loci. K88 fimbriae were expressed in 72% of the isolates and occurred in a diversity of chromosomal genotypic backgrounds. Five major clonal groups were recognized; one group was clearly associated with porcine colibacillosis, and another was associated with human urinary tract infections. The O157:H7 genotype was not closely allied with any of the major groups of clones. The results indicate that O157 E. coli are genetically diverse and strongly suggest that the O157:H7 lineage was not recently derived from other pathogenic strains of the O157 serogroup. PMID:2457555

  15. Draft Genome Sequences of Three European Laboratory Derivatives from Enterohemorrhagic Escherichia coli O157:H7 Strain EDL933, Including Two Plasmids

    PubMed Central

    Fellner, Lea; Huptas, Christopher; Simon, Svenja; Mühlig, Anna; Neuhaus, Klaus

    2016-01-01

    Escherichia coli O157:H7 EDL933, isolated in 1982 in the United States, was the first enterohemorrhagic E. coli (EHEC) strain sequenced. Unfortunately, European labs can no longer receive the original strain. We checked three European EDL933 derivatives and found major genetic deviations (deletions, inversions) in two strains. All EDL933 strains contain the cryptic EHEC-plasmid, not reported before. PMID:27056239

  16. Draft Genome Sequences of Escherichia coli O157:H7 Strains Rafaela_II (Clade 8) and 7.1_Anguil (Clade 6) from Cattle in Argentina

    PubMed Central

    Amigo, Natalia; Puebla, Andrea Fabiana; Farber, Marisa Diana

    2015-01-01

    Escherichia coli O157:H7 is a major etiologic agent of diseases in humans that cause diarrhea, hemorrhagic colitis, and hemolytic-uremic syndrome. Here, we report the draft genome sequences of two strains isolated from cattle that had high levels of Shiga toxin 2 and high lethality in mice. PMID:26067964

  17. Draft Genome Sequences of Escherichia coli O157:H7 Strains Rafaela_II (Clade 8) and 7.1_Anguil (Clade 6) from Cattle in Argentina.

    PubMed

    Amadio, Ariel Fernando; Amigo, Natalia; Puebla, Andrea Fabiana; Farber, Marisa Diana; Cataldi, Angel Adrián

    2015-01-01

    Escherichia coli O157:H7 is a major etiologic agent of diseases in humans that cause diarrhea, hemorrhagic colitis, and hemolytic-uremic syndrome. Here, we report the draft genome sequences of two strains isolated from cattle that had high levels of Shiga toxin 2 and high lethality in mice. PMID:26067964

  18. Phage-typing of Vero-cytotoxin (VT) producing Escherichia coli O157 isolated in the United Kingdom.

    PubMed Central

    Frost, J. A.; Smith, H. R.; Willshaw, G. A.; Scotland, S. M.; Gross, R. J.; Rowe, B.

    1989-01-01

    Vero-cytotoxin (VT) producing Escherichia coli serogroup O157 have been isolated from patients with diarrhoea, haemorrhagic colitis (HC) and haemolytic uraemic syndrome (HUS). A phage-typing scheme developed in Canada has been used to type 155 VT+ E. coli O157 serogroup isolated from sporadic infections in the UK since 1983, and 48 strains from HC or HUS outbreaks. Twelve phage types were identified of which three, types 49, 51 and 52, have not been found in North America. All strains carried a 60 x 10(6) plasmid and most VT1+VT2+ strains also had a 5 x 10(6) plasmid coding for colicin D production. The majority of strains producing both VT1 and VT2 belonged to phage type 1, or the related types 4, 8 and 14. Most strains producing only VT2 belonged to types 2 or 49. Four outbreaks were included in the survey. Three had strains of a single phage type while strains from the fourth outbreak were more variable. The distribution of phage types throughout the UK showed no marked geographical variations. PMID:2673827

  19. [In vitro antibacterial activity of faropenem, a novel oral penem antibiotic, against enterohemorrhagic Escherichia coli O157 strains].

    PubMed

    Nasu, T; Okamoto, K; Nakanishi, T; Nishino, T

    1999-08-01

    Against enterohemorrhagic Escherichia coli (EHEC) O157 clinically isolated, the effects of faropenem (FRPM), a novel oral penem antibiotic, on the MICs, bactericidal activity, verotoxin (VT)-release, and lipopolysaccharide (LPS)-release were investigated in vitro and compared with those of other types of antibacterial agents. The MICs of FRPM in aerobic and anaerobic culture condition, were 0.78 and 0.39 microgram/ml, respectively. In aerobic condition, FRPM was more active than ampicillin, amoxicillin (AMPC), fosfomycin (FOM), kanamycin (KM), minocycline (MINO), and clarithromycin (CAM), but was slightly less active than cefdinir (CFDN), cefditoren (CDTR), and norfloxacin (NFLX) against O157 clinical isolates. In anaerobic condition, however, FRPM showed as strong activity as CFDN, CDTR, and NFLX. FOM, NFLX, and KM as well as the beta-lactams including FRPM indicated the powerful bactericidal activity against one strain of O157 clinical isolates. The effects of MINO and CAM were bacteriostatic. FOM and the beta-lactams including FRPM promoted verotoxin type 1 (VT1)-release, but rather suppressed verotoxin type 2 (VT2)-release from the same isolate. NFLX, however, promoted VT1-release and vast amount of VT2-release. In the case of KM, MINO, and CAM, the release suppression of both VT1 and VT2 was observed. FRPM, AMPC, and FOM had very weak activity on LPS-release, while CFDN, CDTR, and NFLX released a large amount of LPS from the strain. KM, MINO, and CAM had relatively weak activity. In these in vitro experiments, FRPM demonstrated the effective profile to the treatment for EHEC infection, except for the effect on VT1-release. These results suggest the possibility that FRPM shows good clinical efficacy for EHEC infection. PMID:10587879

  20. Genome Signatures of Escherichia coli O157:H7 Isolates from the Bovine Host Reservoir▿†

    PubMed Central

    Eppinger, Mark; Mammel, Mark K.; LeClerc, Joseph E.; Ravel, Jacques; Cebula, Thomas A.

    2011-01-01

    Cattle comprise a main reservoir of Shiga toxin-producing Escherichia coli O157:H7 (STEC). The significant differences in host prevalence, transmissibility, and virulence phenotypes among strains from bovine and human sources are of major interest to the public health community and livestock industry. Genomic analysis revealed divergence into three lineages: lineage I and lineage I/II strains are commonly associated with human disease, while lineage II strains are overrepresented in the asymptomatic bovine host reservoir. Growing evidence suggests that genotypic differences between these lineages, such as polymorphisms in Shiga toxin subtypes and synergistically acting virulence factors, are correlated with phenotypic differences in virulence, host ecology, and epidemiology. To assess the genomic plasticity on a genome-wide scale, we have sequenced the whole genome of strain EC869, a bovine-associated E. coli O157:H7 isolate. Comparative phylogenomic analysis of this key isolate enabled us to place accurately bovine lineage II strains within the genetically homogenous E. coli O157:H7 clade. Identification of polymorphic loci that are anchored both in the chromosomal backbone and horizontally acquired regions allowed us to associate bovine genotypes with altered virulence phenotypes and host prevalence. This study catalogued numerous novel lineage II-specific genome signatures, some of which appear to be associated intimately with the altered pathogenic potential and niche adaptation within the bovine rumen. The presented extended list of polymorphic markers is valuable in the development of a robust typing system critical for forensic, diagnostic, and epidemiological studies of this emerging human pathogen. PMID:21421787

  1. [Epidemiological analysis of Shiga toxin-producing Escherichia coli O157 isolates from familial infection].

    PubMed

    Taguchi, M; Seto, K; Kobayashi, K

    2000-02-01

    A total of 201 Shiga toxin-producing Escherichia coli (STEC) O157:H7 isolates from 22 epidemiologically unrelated familial infections in Osaka were analyzed by various epidemiological markers, such as Shiga toxin (STx) typing, antimicrobial resistant patterns, colicine typing, plasmid profiles and pulsed-field gel electrophoresis (PFGE) typing. There were two cases where different type strains were detected in a family (family No. 21 and 22). In the family No. 21, three different strains were isolated from a 5-year-old male infant; one identical with that from his mother, and the others different in 4 markers except STx type. In the family No. 22, two kinds of strain were detected in a 48-year-old father; one identical with those from other members of the family, and the other different in STx, plasmid profile and PFGE types. These facts showed the possibility of a simultaneous double infection from the common sources of infectious factors or a successive reinfection with different types of the agents. Identical marker strains were detected from 8 out of 12 familial infection cases from July to September. Although infectious sources of these cases are not yet clearly identified, these results of epidemiological markers analysis indicate a probable circulation of the common contaminated foodstuffs. A combined use of phenotypic and genotypic tests were shown to be useful for the epidemiological analysis. Further, it seemed necessary to examine epidemiological markers of more than one strain in familial infection or identical facilities generation cases. And also a collective analysis of the relating factors such as biological markers of the causative agents, the list of eaten foodstuffs, and successive outbreaks of the patients was thought most important. PMID:10741000

  2. Evaluation of techniques for enrichment and isolation of Escherichia coli O157:H7 from artificially contaminated sprouts.

    PubMed

    Weagant, S D; Bound, A J

    2001-12-01

    Because sprouted seed products are kept wet during and after production, have high levels of nutrients, and a neutral pH, they are subject to the outgrowth of pathogens such as Escherichia coli O157:H7. For these same reasons, these products also contain high levels of heterotrophic organisms and in particular coliform bacteria. Recent outbreaks have focused attention on the need to improve methodology for isolating this pathogen from sprouts. When 40 E. coli O157:H7 strains were grown in pure culture in enterohemorrhagic E. coli enrichment broth (EEB) as prescribed in the U.S. FDA-Bacteriological Analytical Manual (FDA-BAM) and in EEB modified by varying the cefixime concentration, outgrowth for all strains in EEB was inhibited at 0.05 mg/l but for only 2 of 40 strains when the cefixime level was adjusted to 0.0125 mg/l. These two enrichment formulae were compared to modified E. coli broth (mEC), modified Tryptic Soy Broth with 20 mg/l novobiocin (mTSB + N), modified Buffered Peptone Water (mBPW), and mBPW with added 10 mg/l acriflavin, 10 mg/l cefsulodin, and 8 mg/l vancomycin (mBPW + ACV) for isolation of E. coli O157:H7 from sprouts. These comparisons were performed using low-level (0.12 to 0.42 cfu/g) artificially contaminated alfalfa and mixed salad sprouts. After enrichment, two isolation methods were compared for recovery; direct plating to Tellurite-Cefixime Sorbitol MacConkey agar (TCSMAC) and immunomagnetic separation (IMS) (Dynabeads anti-E. coli O157, Dynal, Oslo, Norway) followed by plating to TCSMAC. In addition, an immunoprecipitin detection kit, VIP (BioControl, Bellevue, WA), was evaluated for detection after enrichment. We found that five of the six enrichments were equivalent for detection or recovery while one enrichment (mTSB + N without agitation) was less productive. Incubation for 24 h was more effective in recovering E. coli O157:H7 from sprouts than 6 h for all enrichment broths. Plating after IMS was more productive than direct plating

  3. Fitness of outbreak and environmental strains of Escherichia coli O157:H7 in aerosolizable soil and association of clonal variation in stress gene regulation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Airborne dust from feedlots is a potential mechanism of contamination of nearby vegetable crops with Escherichia coli O157:H7 (EcO157). We compared the fitness of clinical and environmental strains of EcO157 in <45 µm soil from a spinach farm. Differences in survival were observed among the 35 strai...

  4. Biotic and abiotic variables affecting internalization and fate of Escherichia coli O157:H7 isolates in leafy green roots.

    PubMed

    Erickson, Marilyn C; Webb, Cathy C; Davey, Lindsey E; Payton, Alison S; Flitcroft, Ian D; Doyle, Michael P

    2014-06-01

    Preharvest internalization of Escherichia coli O157:H7 into the roots of leafy greens is a food safety risk because the pathogen may be systemically transported to edible portions of the plant. In this study, both abiotic (degree of soil moisture) and biotic (E. coli O157:H7 exposure, presence of Shiga toxin genes, and type of leafy green) factors were examined to determine their potential effects on pathogen internalization into roots of leafy greens. Using field soil that should have an active indigenous microbial community, internalized populations in lettuce roots were 0.8 to 1.6 log CFU/g after exposure to soil containing E. coli O157:H7 at 5.6 to 6.1 log CFU/g. Internalization of E. coli O157:H7 into leafy green plant roots was higher when E. coli O157:H7 populations in soil were increased to 7 or 8 log CFU/g or when the soil was saturated with water. No differences were noted in the extent to which internalization of E. coli O157:H7 occurred in spinach, lettuce, or parsley roots; however, in saturated soil, maximum levels in parsley occurred later than did those in spinach or lettuce. Translocation of E. coli O157:H7 from roots to leaves was rare; therefore, decreases observed in root populations over time were likely the result of inactivation within the plant tissue. Shiga toxin-negative (nontoxigenic) E. coli O157:H7 isolates were more stable than were virulent isolates in soil, but the degree of internalization of E. coli O157:H7 into roots did not differ between isolate type. Therefore, these nontoxigenic isolates could be used as surrogates for virulent isolates in field trials involving internalization. PMID:24853507

  5. Identification and Characterization of a Peculiar vtx2-Converting Phage Frequently Present in Verocytotoxin-Producing Escherichia coli O157 Isolated from Human Infections

    PubMed Central

    Grande, Laura; Michelacci, Valeria; Fioravanti, Rosa; Gally, David; Xu, Xuefang; La Ragione, Roberto; Anjum, Muna; Wu, Guanghui; Caprioli, Alfredo; Morabito, Stefano

    2014-01-01

    Certain verocytotoxin-producing Escherichia coli (VTEC) O157 phage types (PTs), such as PT8 and PT2, are associated with severe human infections, while others, such as PT21, seem to be restricted to cattle. In an attempt to delve into the mechanisms underlying such a differential distribution of PTs, we performed microarray comparison of human PT8 and animal PT21 VTEC O157 isolates. The main differences observed were in the vtx2-converting phages, with the PT21 strains bearing a phage identical to that present in the reference strain EDL933, BP933W, and all the PT8 isolates displaying lack of hybridization in some regions of the phage genome. We focused on the region spanning the gam and cII genes and developed a PCR tool to investigate the presence of PT8-like phages in a panel of VTEC O157 strains belonging to different PTs and determined that a vtx2 phage reacting with the primers deployed, which we named Φ8, was more frequent in VTEC O157 strains from human disease than in bovine strains. No differences were observed in the production of the VT2 mRNA when Φ8-positive strains were compared with VTEC O157 possessing BP933W. Nevertheless, we show that the gam-cII region of phage Φ8 might carry genetic determinants downregulating the transcription of the genes encoding the components of the type III secretion system borne on the locus of enterocyte effacement pathogenicity island. PMID:24799627

  6. Comparative genomic analysis and adherence characteristics of supershedder strains of Escherichia coli O157:H7

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Shiga toxin-producing Escherichia coli O157:H7 (O157) is a zoonotic foodborne pathogen of major public health concern that results in considerable intestinal and extra-intestinal illness in humans. Asymptomatic cattle are the primary reservoir of O157 and harbor the pathogen at the terminal recto-an...

  7. The Lpp lipoprotein suppresses motility in a biofilm-forming strain of Escherichia coli O157:H7

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In Escherichia coli O157:H7 strain ATCC 43895, a guanine to thymine transversion in a gene involved in fimbrial (curlifiber) synthesis created strain 43895OR. Strain 43895OR produces an abundant extracellular matrix rich in curli fibers and generates dense biofilms on solid surfaces. We investigated...

  8. Dual-serotype biofilm formation by shiga toxin-producing Escherichia coli O157:H7 and O26:H11 strains.

    PubMed

    Wang, Rong; Kalchayanand, Norasak; Bono, James L; Schmidt, John W; Bosilevac, Joseph M

    2012-09-01

    Escherichia coli O26:H11 strains were able to outgrow O157:H7 companion strains in planktonic and biofilm phases and also to effectively compete with precolonized O157:H7 cells to establish themselves in mixed biofilms. E. coli O157:H7 strains were unable to displace preformed O26:H11 biofilms. Therefore, E. coli O26:H11 remains a potential risk in food safety. PMID:22706056

  9. Esherichia coli serotype O157:H7 retention on solid surfaces and peroxide resistance is enhanced by dual-strain biofilm formation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In a previous study we showed that an Escherichia coli O157:H7 strain that was unable to form biofilm could persist in large numbers in dual-strain biofilms formed with an E. coli O-:H4 companion strain. In this study we tested additional companion strains for their ability to retain serotype O157:H...

  10. Prevalence and molecular characterization of sorbitol fermenting and non-fermenting Escherichia coli O157:H7(+)/H7(-) isolated from cattle at slaughterhouse and slaughterhouse wastewater.

    PubMed

    Ayaz, Naim Deniz; Gencay, Yilmaz Emre; Erol, Irfan

    2014-03-17

    The prevalence and seasonal distribution of E. coli O157:H7(+)/H7(-) in an array of aged cattle at slaughter and its dissemination with slaughterhouse wastewater over a two year period in Turkey were investigated. For this purpose, a total of 720 samples (240 rectoanal mucosal swap [RAMS], 240 carcass sponge and 240 bile samples) of 240 cattle categorized according to age, gender, breed and sampling site were collected along with additional 24 wastewater samples and were subjected to immunomagnetic separation based cultivation technique to efficiently isolate E. coli O157 from the background flora. Identification (rfbEO157, fliCh7), detection of major virulence factors (stx1, stx2, eaeA, hly, lpfA1-3 and espA), intimin variants (eae-α1, eae-α2, eae-β, eae-β1, eae-β2, eae-γ1 and eae-γ2/θ) and shiga toxin variants (stx1c, stx1d, stx2c, stx2d, stx2e, stx2f and stx2g) of all the isolates were assessed by PCR. From 10 (4.2%) of RAMS and 11 (4.6%) of carcass sponge samples and 5 (20.8%) of slaughterhouse wastewater samples, a total of 102 colonies (99 sorbitol negative and 3 sorbitol positive) were isolated. Overall, 17 (7.1%) and 15 (6.3%) of 240 sampled cattle were shown to harbor E. coli O157 and E. coli O157:H7, respectively either in their RAMS or carcass sponge samples analyzed. Statistically significant differences between categories; season, age, gender and breed of cattle were not observed (p>0.05). None of the isolated E. coli O157:H7(+)/H7(-) strains harbored any of the investigated intimin types other than eaeγ1 or shiga toxin variants stx1d, stx2e, stx2f or stx2g while all were lpfA1-3(+) except 5 E. coli O157:H7(-) strains. Intimin variant eaeγ1 and shiga toxin 1 variant stx1c were detected from all of the eaeA(+) (97/102, 95.1%) and stx1(+) (32/102, 31.3%) strains, respectively while from stx2(+) (80/102, 78.4%) isolates, both stx2c (68/80, 85.0%) and stx2d (12/80, 15.0%) variants were determined. In the last decade, prevalence of E. coli O157:H7

  11. Construction and characterization of outbreak Escherichia coli O157:H7 surrogate strains for use in field studies.

    PubMed

    Webb, Cathy C; Erickson, Marilyn C; Davey, Lindsey E; Payton, Alison S; Doyle, Michael P

    2014-11-01

    Escherichia coli O157:H7 has been the causative agent of many outbreaks associated with leafy green produce consumption. Elucidating the mechanism by which contamination occurs requires monitoring interactions between the pathogen and the plant under typical production conditions. Intentional introduction of virulent strains into fields is not an acceptable practice. As an alternative, attenuated strains of natural isolates have been used as surrogates of the virulent strains; however, the attachment properties and environmental stabilities of these attenuated isolates may differ from the unattenuated outbreak strains. In this study, the Shiga toxin (stx1, stx2, and/or stx2c) genes as well as the eae gene encoding intimin of two E. coli O157:H7 outbreak isolates, F4546 (1997 alfalfa sprout) and K4492 (2006 lettuce), were deleted. Individual gene deletions were confirmed by polymerase chain reaction (PCR) and DNA sequencing. The mutant strains did not produce Shiga toxin. The growth kinetics of these mutant strains under nutrient-rich and minimal conditions were identical to those of their wild-type strains. Attachment to the surface of lettuce leaves was comparable between wild-type/mutant pairs F4546/MD46 and K4492/MD47. Adherence to soil particles was also comparable between the virulent and surrogate pairs, although the F4546/MD46 pair exhibited statistically greater attachment than the K4492/MD47 pair (p≤0.05). Wild-type and mutant pairs F4546/MD46 and K4492/MD47 inoculated into wet or dry soils had statistically similar survival rates over the 7-day storage period at 20°C. A plasmid, pGFPuv, containing green fluorescent protein was transformed into each of the mutant strains, allowing for ease of identification and detection of surrogate strains on plant material or soil. These pGFPuv-containing surrogate strains will enable the investigation of pathogen interaction with plants and soil in the farm production environment where the virulent pathogen cannot

  12. Specific Single-Cell Isolation of Escherichia coli O157 from Environmental Water Samples by Using Flow Cytometry and Fluorescence-Activated Cell Sorting.

    PubMed

    Ozawa, Shuji; Okabe, Satoshi; Ishii, Satoshi

    2016-08-01

    Contamination of food and water with pathogenic bacteria is of concern. Although culture-independent detection and quantification of pathogens is useful, isolation of pathogenic bacteria is still important when identifying the sources of pathogens. Here, we report the use of flow cytometry (FCM) and fluorescence-activated cell sorting (FACS) to specifically detect and isolate individual Escherichia coli O157:H7 cells from water samples. When present at >10 cells/mL water, target pathogen was specifically detected and isolated. The FACS-sorted E. coli O157:H7 population reflected the original population diversity, in contrast to the populations obtained by immunomagnetic separation. Relative abundance of multiple pathogenic strains is important when performing source-tracking studies; therefore, single-cell isolation with FCM-FACS can be a useful tool to obtain pathogenic bacteria for source tracking purpose. PMID:27182755

  13. Complete Genome Sequences of Escherichia coli O157:H7 Strains SRCC 1675 and 28RC, Which Vary in Acid Resistance

    PubMed Central

    Baranzoni, Gian Marco; Reichenberger, Erin R.; Kim, Gwang-Hee; Breidt, Frederick; Kay, Kathryn; Oh, Deog-Hwan

    2016-01-01

    The level of acid resistance among Escherichia coli O157:H7 strains varies, and strains with higher resistance to acid may have a lower infectious dose. The complete genome sequences belonging to two strains of Escherichia coli O157:H7 with different levels of acid resistance are presented here. PMID:27469964

  14. Complete Genome Sequences of Escherichia coli O157:H7 Strains SRCC 1675 and 28RC, Which Vary in Acid Resistance.

    PubMed

    Baranzoni, Gian Marco; Fratamico, Pina M; Reichenberger, Erin R; Kim, Gwang-Hee; Breidt, Frederick; Kay, Kathryn; Oh, Deog-Hwan

    2016-01-01

    The level of acid resistance among Escherichia coli O157:H7 strains varies, and strains with higher resistance to acid may have a lower infectious dose. The complete genome sequences belonging to two strains of Escherichia coli O157:H7 with different levels of acid resistance are presented here. PMID:27469964

  15. Complete genome sequences of Escherichia coli O157:H7 strains SRCC 1675 and 28RC that vary in acid resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The level of acid resistance among Escherichia coli O157:H7 strains varies, and strains with higher resistance to acid may have a lower infectious dose. The complete genome sequences belonging to two strains of Escherichia coli O157:H7 with different levels of acid resistance are presented....

  16. Comparative Analysis of Super-Shedder Strains of Escherichia coli O157:H7 Reveals Distinctive Genomic Features and a Strongly Aggregative Adherent Phenotype on Bovine Rectoanal Junction Squamous Epithelial Cells

    PubMed Central

    Cote, Rebecca; Katani, Robab; Moreau, Matthew R.; Kudva, Indira T.; Arthur, Terrance M.; DebRoy, Chitrita; Mwangi, Michael M.; Albert, Istvan; Raygoza Garay, Juan Antonio; Li, Lingling; Brandl, Maria T.; Carter, Michelle Q.; Kapur, Vivek

    2015-01-01

    Shiga toxin-producing Escherichia coli O157:H7 (O157) are significant foodborne pathogens and pose a serious threat to public health worldwide. The major reservoirs of O157 are asymptomatic cattle which harbor the organism in the terminal recto-anal junction (RAJ). Some colonized animals, referred to as “super-shedders” (SS), are known to shed O157 in exceptionally large numbers (>104 CFU/g of feces). Recent studies suggest that SS cattle play a major role in the prevalence and transmission of O157, but little is known about the molecular mechanisms associated with super-shedding. Whole genome sequence analysis of an SS O157 strain (SS17) revealed a genome of 5,523,849 bp chromosome with 5,430 open reading frames and two plasmids, pO157 and pSS17, of 94,645 bp and 37,446 bp, respectively. Comparative analyses showed that SS17 is clustered with spinach-associated O157 outbreak strains, and belongs to the lineage I/II, clade 8, D group, and genotype 1, a subgroup of O157 with predicted hyper-virulence. A large number of non-synonymous SNPs and other polymorphisms were identified in SS17 as compared with other O157 strains (EC4115, EDL933, Sakai, TW14359), including in key adherence- and virulence-related loci. Phenotypic analyses revealed a distinctive and strongly adherent aggregative phenotype of SS17 on bovine RAJ stratified squamous epithelial (RSE) cells that was conserved amongst other SS isolates. Molecular genetic and functional analyses of defined mutants of SS17 suggested that the strongly adherent aggregative phenotype amongst SS isolates is LEE-independent, and likely results from a novel mechanism. Taken together, our study provides a rational framework for investigating the molecular mechanisms associated with SS, and strong evidence that SS O157 isolates have distinctive features and use a LEE-independent mechanism for hyper-adherence to bovine rectal epithelial cells. PMID:25664460

  17. Thermal tolerance characteristics of non-O157 Shiga toxigenic strains of Escherichia coli (STEC) in a beef broth model system are similar to those of O157:H7 STEC.

    PubMed

    Vasan, Akhila; Leong, Wan Mei; Ingham, Steve C; Ingham, Barbara H

    2013-07-01

    The non-O157 Shiga toxigenic Escherichia coli (STEC) serogroups most commonly associated with illness are O26, O45, O103, O111, O121, and O145. In the United States, these serogroups are considered adulterants in raw nonintact beef. To begin to understand the behavior of these pathogens in meat systems, we compared the thermal tolerance of acid-adapted cells of non-O157 STEC and O157:H7 STEC in a beef-derived broth. D58°C-values were determined for at least three strains per serogroup, and D54.6°C-values and D63.6°C-values were determined for one strain per serogroup. Each strain was grown to stationary phase in brain heart infusion broth (BHIB; pH 7.0) and inoculated into prewarmed BHIB in a shaking water bath for thermotolerance experiments at 54.6, 58.0, or 63.6°C (three trials per strain). Samples were heated for up to 160 min at 54.6°C, 3 min at 58.0°C, or 45 s at 63.6°C, with periodic sampling followed by rapid cooling and plating on modified Levine's eosin methylene blue agar. For each strain and temperature, the log CFU per milliliter was plotted versus time, and D-values were determined. Across all strains, the least and most heat tolerant STEC serogroups at 58°C were O145 and O157, respectively. D58°C-values in BHIB ranged from 0.44 min for an O145 strain to 1.42 min for an O157:H7 strain. D58°C-values for O157 STEC strains were significantly higher than those for at least one strain in each of the non-O157 STEC serogroups (P < 0.05) except for serogroup O103. At 54.6°C, the most heat-resistant STEC strain belonged to serogroup O103 and was significantly more heat tolerant than the O157:H7 strains (P < 0.05). Grouping the strains, there were no significant differences in heat tolerance between O157 and non-O157 STEC at 63.6°C (P ≥ 0.05). The z-values for non-O157 STEC strains were comparable to those for O157:H7 STEC strains (P ≥ 0.05), ranging from 4.10 to 5.21°C. These results suggest that thermal processing interventions that target

  18. Biochemical Features and Virulence Gene Profiles of Non-O157/O26 Enterohemorrhagic Escherichia coli Strains from Humans in the Yamaguchi Prefecture, Japan.

    PubMed

    Kameyama, Mitsuhiro; Yabata, Junko; Nomura, Yasuharu; Tominaga, Kiyoshi

    2015-01-01

    The biochemical features and virulence gene profiles of 37 enterohemorrhagic Escherichia coli (EHEC) strains belonging to serogroups other than O157 and O26 (non-O157/O26 EHEC) were investigated. All strains were isolated from humans between 2002 and 2013 in the Yamaguchi Prefecture. Serogroup O111 strains were the most common, followed by O103, O121, and O145. Most strains (84%) were negative for sorbose fermentation, whereas only 1 and 2 were negative for sorbitol and rhamnose fermentation, respectively. Two strains lacked β-D-glucuronidase activity. Shiga toxin (stx) subtyping revealed 6 genotypes:stx1a (n = 20), stx1a + stx2a (n = 8), stx2a (n = 4), stx2b (n = 3), stx2a + stx2c (n = 1), and stx2a + stx2d (n = 1). Polymerase chain reaction screening of other toxin and adherence genes showed that astA, subA, and cdtB were present in 5, 2, and 2 strains, respectively. The intimin gene eae was present in 30 strains (81%). Of the 7 eae-negative strains, saa and eibG were found in 3 and 2 strains, respectively; no adherence factors were detected in the remaining 2 strains. The antimicrobial susceptibility profiles of the strains to 12 drugs were examined and 11 strains (30%) showed resistance to 1 or more drugs. Our results revealed that non-O157/O26 EHEC strains exhibit various biochemical phenotypes and carry several toxins and adherence factor genes. PMID:25672402

  19. Sensitivity of Escherichia coli O157:H7 strain 932 to selected anticoccidial drugs in broiler chicks.

    PubMed

    Stanley, V G; Woldesenbet, S; Gray, C; Hinton, A

    1996-01-01

    The ability of selected anticoccidial drugs to inhibit the colonization of day-old male broiler chicks (Cornish Rocks) by Escherichia coli O157:H7, strain 932 was examined. Chicks were challenged with 1.8 x 10(9) E. coli O157:H7 on Day 1, and fed diets supplemented with three selected anticoccidial drugs; monensin, nicarbazin, or robenidine. The cecal and colon fecal contents of the chicks were removed on Day 7, 14, and 21 postinoculation and examined for the concentration of E. coli O157: H7 per gram of contents. Monensin effectively reduced cecal and colon colonization of the chicks by E. coli O157:H7. By Day 7, there were significant reductions in the bacterial population of the cecal contents of chicks receiving the monensin-medicated feed, and by Day 21 no E. coli O157:H7 was recovered from the cecal and colon contents. The bacterial counts in the colon contents of the nicarbazin- and robenidine-medicated and unmedicated chicks were significantly higher than the monensin-treated chicks. Bacterial populations in the colon contents were high only when there were high bacterial concentrations in the cecal contents. PMID:8650109

  20. Genetically marked strains of Shiga toxin-producing O157:H7 and non-O157 Escherichia coli: Tools for detection and modelling

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Shiga toxin-producing E. coli (STEC) are among the most important foodborne pathogens in the United States and worldwide. Nearly half of all STEC-induced diarrheal disease in the United States is caused by STEC O157:H7 while non-O157 STEC account for the remaining illnesses. Thus, the USDA Food Safe...

  1. Multiple mechanisms responsible for strong Congo red-binding variants of Escherichia coli O157:H7 strains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    High variability in the expression of csgD-dependent, biofilm-forming and adhesive properties is common among Shiga toxin-producing Escherichia coli (STEC). Although many strains of serotype O157:H7 form little biofilm, conversion to stronger biofilm phenotypes has been observed. In this study we sc...

  2. A novel transducible chimeric phage from Escherichia coli O157:H7 Sakai strain encoding Stx1 production.

    PubMed

    Sváb, Domonkos; Bálint, Balázs; Maróti, Gergely; Tóth, István

    2015-01-01

    Shiga toxin-producing Escherichia coli (STEC), and especially enterohaemorrhagic E. coli (EHEC) are important, highly virulent zoonotic and food-borne pathogens. The genes encoding their key virulence factors, the Shiga toxins, are distributed by converting bacteriophages, the Stx phages. In this study we isolated a new type of inducible Stx phage carrying the stx1 gene cluster from the prototypic EHEC O157:H7 Sakai strain. The phage showed Podoviridae morphology, and was capable of converting the E. coli K-12 MG1655 strain to Shiga toxin-producing phenotype. The majority of the phage genes originate from the stx2-encoding Sakai prophage Sp5, with major rearrangements in its genome. Beside certain minor recombinations, the genomic region originally containing the stx2 genes in Sp5 was replaced by a region containing six open reading frames from prophage Sp15 including stx1 genes. The rearranged genome, together with the carriage of stx1 genes, the morphology and the capability of lysogenic conversion represent a new type of recombinant Stx1 converting phage from the Sakai strain. PMID:25445656

  3. SHIGA TOXIN BACTERIOPHAGE INSERTION SITES IDENTIFY DIVERSE ESCHERIHICA COLI O157:H7 STRAIN TYPES WITH DISTRIBUTIONS BIASED TO THE BOVINE HOST RESERVOIR

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: The incidence of human disease caused by E. coli O157:H7 is surprisingly low considering its ubiquitous distribution (and frequently, high prevalence) in the bovine reservoir and its low infectious dose for humans. The purpose of this study was to detect E. coli O157:H7 strain types in t...

  4. Genomic Comparisons and Shiga Toxin Production among Escherichia coli O157:H7 Isolates from a Day Care Center Outbreak and Sporadic Cases in Southeastern Wisconsin

    PubMed Central

    Gouveia, S.; Proctor, M. E.; Lee, M.-S.; Luchansky, J. B.; Kaspar, C. W.

    1998-01-01

    Contour-clamped homogeneous electric field pulsed-field gel electrophoresis (CHEF-PFGE) was used to compare Wisconsin isolates of Escherichia coli O157:H7, including 39 isolates from a 1994 day care center outbreak, 28 isolates from 18 individuals from the surrounding geographic area with sporadic cases occurring during the 3 months before the outbreak, and 3 isolates, collected in 1995, from patients with hemolytic-uremic syndrome (HUS) who were from eastern Wisconsin counties other than those inhabited by the day care center and sporadic-case individuals. The technique of CHEF-PFGE using XbaI identified seven highly related restriction endonuclease digestion profiles (REDPs) (93 to 98% similarity) among the 39 day care center isolates and nine XbaI REDPs (63 to 93% similarity) among the 28 isolates from sporadic-case individuals, including REDP 33, which was exhibited by both day care and sporadic-case isolates. PFGE analyses of sequential E. coli O157:H7 isolates from symptomatic day care center attendees revealed that the REDPs of 25 isolates from eight patients were indistinguishable whereas the REDPs of 2 of 6 isolates from two patients differed slightly (93 to 95% similarity). The REDPs of the three isolates from 1995 HUS patients were 78 to 83% similar, with REDP 26 being exhibited by one HUS-associated isolate and an isolate from one day care attendee who did not develop HUS. The genes for both Shiga toxins I and II (stx1 and stx2, respectively) were detected in all but one isolate (sporadic case), and Shiga toxin production by the day care center isolates was not significantly different from that of the other isolates, including the three HUS-associated isolates. Analyses of E. coli O157:H7 isolates from both the day care center outbreak and sporadic cases by CHEF-PFGE permitted us to define the REDP variability of an outbreak and geographic region and demonstrated that the day care center outbreak and a HUS case in 1995 were caused by E. coli O157:H7

  5. Escherichia coli O157:H7 bacteriophage (phi)241 isolated from an industrial cucumber fermentation at high acidity and salinity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A novel phage, (phi)241, specific for Escherichia coli O157:H7 was isolated from an industrial cucumber fermentation where both acidity (pH less than or equal to 3.7) and salinity (greater than or equal to 5% NaCl) were high. The phage belongs to the Myoviridae family. Its latent period was 15 min a...

  6. Phylogenetic Classification of Escherichia coli O157:H7 Strains of Human and Bovine Origin Using a Novel Set of Nucleotide Polymorphisms

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background Cattle are a reservoir of Shiga toxin-producing Escherichia coli O157:H7 (STEC O157), and are known to harbor subtypes not typically found in clinically-ill humans. Consequently, nucleotide polymorphisms previously discovered via isolates originating from human outbreaks may be restricte...

  7. Intra and inter-strain differences in fitness of Escherichia coli O157:H7 to protozoan predation and survival in soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Introduction: Escherichia coli O157:H7 (EcO157) associated with 2006 spinach outbreak appears to have persisted as the organism was later isolated from environmental samples in the produce production areas of the central coast of California. Survival in harsh environments may be linked to the inhere...

  8. Phylogenetic classification of Escherichia coli O157:H7 strains of human and bovine origin using a novel set of nucleotide polymorphisms

    PubMed Central

    Clawson, Michael L; Keen, James E; Smith, Timothy PL; Durso, Lisa M; McDaneld, Tara G; Mandrell, Robert E; Davis, Margaret A; Bono, James L

    2009-01-01

    Background Cattle are a reservoir of Shiga toxin-producing Escherichia coli O157:H7 (STEC O157), and are known to harbor subtypes not typically found in clinically ill humans. Consequently, nucleotide polymorphisms previously discovered via strains originating from human outbreaks may be restricted in their ability to distinguish STEC O157 genetic subtypes present in cattle. The objectives of this study were firstly to identify nucleotide polymorphisms in a diverse sampling of human and bovine STEC O157 strains, secondly to classify strains of either bovine or human origin by polymorphism-derived genotypes, and finally to compare the genotype diversity with pulsed-field gel electrophoresis (PFGE), a method currently used for assessing STEC O157 diversity. Results High-throughput 454 sequencing of pooled STEC O157 strain DNAs from human clinical cases (n = 91) and cattle (n = 102) identified 16,218 putative polymorphisms. From those, 178 were selected primarily within genomic regions conserved across E. coli serotypes and genotyped in 261 STEC O157 strains. Forty-two unique genotypes were observed that are tagged by a minimal set of 32 polymorphisms. Phylogenetic trees of the genotypes are divided into clades that represent strains of cattle origin, or cattle and human origin. Although PFGE diversity surpassed genotype diversity overall, ten PFGE patterns each occurred with multiple strains having different genotypes. Conclusions Deep sequencing of pooled STEC O157 DNAs proved highly effective in polymorphism discovery. A polymorphism set has been identified that characterizes genetic diversity within STEC O157 strains of bovine origin, and a subset observed in human strains. The set may complement current techniques used to classify strains implicated in disease outbreaks. PMID:19463166

  9. [Isolation of enteropathogenic Escherichia coli O157:H16 identified in a diarrhea case in a child and his household contacts in La Pampa Province, Argentina].

    PubMed

    Silveyra, Ivana M; Pereyra, Adriana M; Alvarez, María G; Villagran, Mariana D; Baroni, Andrea B; Deza, Natalia; Carbonari, Claudia C; Miliwebsky, Elizabeth; Rivas, Marta

    2015-01-01

    Enteropathogenic Escherichia coli (EPEC) is a major causative agent of acute diarrhea in children in developing countries. This pathotype is divided into typical EPEC (tEPEC) and atypical EPEC (aEPEC), based on the presence of the bfp virulence factor associated with adhesion, encoded in the pEAF plasmid. In the present study, the isolation of aEPEC O157:H16 from a bloody diarrhea case in a child and his household contacts (mother, father and sister) is described. The strain was characterized as E. coli O157:H16 eae-ɛ-positive, sorbitol fermenter with β-glucuronidase activity, susceptible to all antimicrobials tested, and negative for virulence factors stx1, stx2, ehxA and bfp. XbaI-PFGE performed on all isolates showed the AREXHX01.1040 macrorestriction pattern, with 100% similarity. These results highlight the importance of epidemiological surveillance of E. coli O157-associated diarrhea cases identified in children and their family contacts, as well as the incorporation of molecular techniques that allow the detection of the different E. coli pathotypes. PMID:26627113

  10. Multiple-locus variable-number tandem repeat analysis for strain discrimination of non-O157 Shiga toxin-producing Escherichia coli.

    PubMed

    Timmons, Chris; Trees, Eija; Ribot, Efrain M; Gerner-Smidt, Peter; LaFon, Patti; Im, Sung; Ma, Li Maria

    2016-06-01

    Non-O157 Shiga toxin-producing Escherichia coli (STEC) are foodborne pathogens of growing concern worldwide that have been associated with several recent multistate and multinational outbreaks of foodborne illness. Rapid and sensitive molecular-based bacterial strain discrimination methods are critical for timely outbreak identification and contaminated food source traceback. One such method, multiple-locus variable-number tandem repeat analysis (MLVA), is being used with increasing frequency in foodborne illness outbreak investigations to augment the current gold standard bacterial subtyping technique, pulsed-field gel electrophoresis (PFGE). The objective of this study was to develop a MLVA assay for intra- and inter-serogroup discrimination of six major non-O157 STEC serogroups-O26, O111, O103, O121, O45, and O145-and perform a preliminary internal validation of the method on a limited number of clinical isolates. The resultant MLVA scheme consists of ten variable number tandem repeat (VNTR) loci amplified in three multiplex PCR reactions. Sixty-five unique MLVA types were obtained among 84 clinical non-O157 STEC strains comprised of geographically diverse sporadic and outbreak related isolates. Compared to PFGE, the developed MLVA scheme allowed similar discrimination among serogroups O26, O111, O103, and O121 but not among O145 and O45. To more fully compare the discriminatory power of this preliminary MLVA method to PFGE and to determine its epidemiological congruence, a thorough internal and external validation needs to be performed on a carefully selected large panel of strains, including multiple isolates from single outbreaks. PMID:27071532

  11. RcsB Contributes to the Distinct Stress Fitness among Escherichia coli O157:H7 Curli Variants of the 1993 Hamburger-Associated Outbreak Strains

    PubMed Central

    Parker, Craig T.; Louie, Jacqueline W.; Huynh, Steven; Fagerquist, Clifton K.; Mandrell, Robert E.

    2012-01-01

    Curli are adhesive fimbriae of Enterobactericaeae and are involved in surface attachment, cell aggregation, and biofilm formation. We reported previously that curli-producing (C+) variants of E. coli O157:H7 (EcO157) were much more acid sensitive than their corresponding curli-deficient (C−) variants; however, this difference was not linked to the curli fimbriae per se. Here, we investigated the underlying molecular basis of this phenotypic divergence. We identified large deletions in the rcsB gene of C+ variants isolated from the 1993 U.S. hamburger-associated outbreak strains. rcsB encodes the response regulator of the RcsCDB two-component signal transduction system, which regulates curli biogenesis negatively but acid resistance positively. Further comparison of stress fitness revealed that C+ variants were also significantly more sensitive to heat shock but were resistant to osmotic stress and oxidative damage, similar to C− variants. Transcriptomics analysis uncovered a large number of differentially expressed genes between the curli variants, characterized by enhanced expression in C+ variants of genes related to biofilm formation, virulence, catabolic activity, and nutrient uptake but marked decreases in transcription of genes related to various types of stress resistance. Supplying C+ variants with a functional rcsB restored resistance to heat shock and acid challenge in cells but blocked curli production, confirming that inactivation of RcsB in C+ variants was the basis of fitness segregation within the EcO157 population. This study provides an example of how genome instability of EcO157 promotes intrapopulation diversification, generating subpopulations carrying an array of distinct phenotypes that may confer the pathogen with survival advantages in diverse environments. PMID:22923406

  12. GREATER DIVERSITY OF SHIGA TOXIN-ENCODING BACTERIOPHAGE INSERTION SITES AMONG ESCHERICHA COLI O157:H7 ISOLATES FROM CATTLE THAN IN THOSE FROM HUMANS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: Escherichia coli O157:H7, a zoonotic human pathogen with reservoir in domestic cattle, produces Shiga toxin(s) encoded by bacteriophages. Chromosomal insertion sites of these bacteriophages define three principal genotypes (Clusters 1 - 3 ) among clinical isolates of E. coli O157:H7. ...

  13. Phylogenetic Classification of Escherichia coli O157:H7 Isolates of Human and Bovine Origin Using a Novel Set of Nucleotide Polymorphisms

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background Cattle are a reservoir of Shiga toxin-producing Escherichia coli O157:H7 (STEC O157), and are known to harbor subtypes not typically found in clinically-ill humans. Consequently, nucleotide polymorphisms previously discovered via isolates originating from human outbreaks may be restricte...

  14. Design and evaluation of two-stage multiplex real-time PCR method for detecting O157:H7 and non-O157 STEC strains from beef samples

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Introduction: E. coli O157:H7 was first recognized as a human pathogen in 1982 and until recently was the only E. coli strain mandated for testing by the USDA. In June 2012, the USDA declared six additional Shiga-toxin producing E. coli serogroups (O26, O45, O103, O111, O121, and O145) as adulterant...

  15. Enhanced Virulence of the Escherichia coli O157:H7 Spinach-Associated Outbreak Strain in Two Animal Models Is Associated with Higher Levels of Stx2 Production after Induction with Ciprofloxacin

    PubMed Central

    Zangari, T.; Melton-Celsa, A. R.; Panda, A.; Smith, M. A.; Tatarov, I.; De Tolla, L.

    2014-01-01

    Shiga toxin (Stx)-producing Escherichia coli (STEC) causes hemorrhagic colitis and the hemolytic-uremic syndrome (HUS). STEC strains may produce Stx1a and/or Stx2a or variants of either toxin. A 2006 spinach-associated outbreak of STEC O157:H7 resulted in higher hospitalization and HUS rates than previous STEC outbreaks. The spinach isolate, strain K3995, contains both stx2a and stx2c. We hypothesized that the enhanced virulence of K3995 reflects the combination of stx2 alleles (carried on lysogenic phages) and/or the amount of Stx2 made by that strain. We compared the virulence of K3995 to those of other O157:H7 isolates and an isogenic Stx2 mutant in rabbits and mice. We also measured the relative levels of Stx2 produced from those strains with or without induction of the stx-carrying phage. Some rabbits infected with K3995 exhibited intestinal pathology and succumbed to infection, while none of those infected with O157:H7 strain 2812 (Stx1a+ Stx2a+) died or showed pathological signs. Rabbits infected with the isogenic Stx2a mutant K3995 stx2a::cat were not colonized as well as those infected with K3995 and exhibited no signs of disease. In the streptomycin-treated mouse model, more animals infected with K3995 died than did those infected with O157:H7 strain 86-24 (Stx2a+). Additionally, K3995 produced higher levels of total Stx2 and toxin phage DNA in cultures after phage induction than did 86-24. Our results demonstrate the greater virulence of K3995 compared to other O157:H7 strains in rabbits and mice. We conclude that this enhanced virulence is linked to higher levels of Stx2 expression as a consequence of increased phage induction. PMID:25225244

  16. Prevalence, characterization and clonal analysis of Escherichia coli O157 non-H7 serotypes that carry eae alleles

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We characterized nineteen O157 non-H7 strains that were isolated from food, water, and both symptomatic and asymptomatic patients in various countries. All the isolates were serologically and genetically confirmed to be O157 non-H7 strains, but could not be H serotyped. None of the strains had tra...

  17. Comparison of different sample preparation procedures for the detection and isolation of Escherichia coli O157:H7 and Non-O157 STECs from leafy greens and cilantro.

    PubMed

    Kase, Julie A; Maounounen-Laasri, Anna; Son, Insook; Deer, Deanne M; Borenstein, Stacey; Prezioso, Samantha; Hammack, Thomas S

    2012-12-01

    The FDA Bacteriological Analytical Manual (BAM) method for the detection/isolation of Shiga toxin-producing Escherichia coli (STEC) involves enrichment of produce rinses, blended homogenates or stomached homogenates. However, the effectiveness of rinsing produce to remove attached bacteria is largely unknown. Moreover, PCR inhibitors can be released under physical treatment. The study objective was to determine the relative effectiveness of recovery methods for STEC contaminated produce. Spinach, lettuce, and cilantro were contaminated with E. coli O157:H7 or a non-O157 STEC, subjected to both the BAM method and a soak method, and tested by real-time PCR and cultural methods. For O157:H7 and non-O157:H7 STECs, the soak method was significantly more productive than leafy green rinses. Of 320 test portions, PCR of recovered colonies confirmed 148 were positive by rinsing and 271 were positive by soaking (an 83% increase in sensitivity). For recovery of O157:H7 from cilantro, of 60 test portions, positives were 38 by soaking, 41 by stomaching, and 28 by blending. Soaking and stomaching were significantly more productive than blending, although soaking was only arithmetically superior to stomaching. Based upon these results, it is recommended that a soak method replace the current BAM procedures. PMID:22986209

  18. Phenotypic and Genotypic Characterization of Biofilm Forming Capabilities in Non-O157 Shiga Toxin-Producing Escherichia coli Strains

    PubMed Central

    Hofmann, Christopher S.; Cottrell, Bryan J.; Strobaugh Jr, Terence P.; Paoli, George C.; Nguyen, Ly-Huong; Yan, Xianghe

    2013-01-01

    The biofilm life style helps bacteria resist oxidative stress, desiccation, antibiotic treatment, and starvation. Biofilm formation involves a complex regulatory gene network controlled by various environmental signals. It was previously shown that prophage insertions in mlrA and heterogeneous mutations in rpoS constituted major obstacles limiting biofilm formation and the expression of extracellular curli fibers in strains of Escherichia coli serotype O157:H7. The purpose of this study was to test strains from other important serotypes of Shiga toxin-producing E. coli (STEC) (O26, O45, O103, O111, O113, O121, and O145) for similar regulatory restrictions. In a small but diverse collection of biofilm-forming and non-forming strains, mlrA prophage insertions were identified in only 4 of the 19 strains (serotypes O103, O113, and O145). Only the STEC O103 and O113 strains could be complemented by a trans-copy of mlrA to restore curli production and Congo red (CR) dye affinity. RpoS mutations were found in 5 strains (4 serotypes), each with low CR affinity, and the defects were moderately restored by a wild-type copy of rpoS in 2 of the 3 strains attempted. Fourteen strains in this study showed no or weak biofilm formation, of which 9 could be explained by prophage insertions or rpoS mutations. However, each of the remaining five biofilm-deficient strains, as well as the two O145 strains that could not be complemented by mlrA, showed complete or nearly complete lack of motility. This study indicates that mlrA prophage insertions and rpoS mutations do limit biofilm and curli expression in the non-serotype O157:H7 STEC but prophage insertions may not be as common as in serotype O157:H7 strains. The results also suggest that lack of motility provides a third major factor limiting biofilm formation in the non-O157:H7 STEC. Understanding biofilm regulatory mechanisms will prove beneficial in reducing pathogen survival and enhancing food safety. PMID:24386426

  19. Transport and Straining of E. coli O157:H7 in Saturated Porous Media

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The transport and deposition behavior of pathogenic Escherichia coli O157:H7 was studied under unfavorable electrostatic conditions in saturated quartz sands of various sizes (710, 360, 240, and 150 mm) and at several flow rates. At a given velocity, column effluent breakthrough values for E. coli t...

  20. Incorporation of Escherichia coli O157:H7 in dual-species biofilms with Ralstonia insidiosa, a primary colonizer for the development of heterogeneous biofilms

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The presence of strong biofilm forming microflora could potentially enhance the survival of Escherichia coli O157:H7 (EcO157) in harsh environment. One strain of Ralstonia insidiosa isolated from produce processing environments, previously displayed a synergistic interaction with EcO157 in dual-spec...

  1. Antagonistic effects of probiotic Escherichia coli Nissle 1917 on EHEC strains of serotype O104:H4 and O157:H7.

    PubMed

    Rund, Stefan A; Rohde, Holger; Sonnenborn, Ulrich; Oelschlaeger, Tobias A

    2013-01-01

    The largest EHEC outbreak up to now in Germany occurred in 2011. It was caused by the non-O157:H7 Shiga-toxinogenic enterohemorrhagic E. coli strain O104:H4. This strain encodes in addition to the Shiga toxin 2 (Stx2), responsible for the hemolytic uremic syndrome (HUS), several adhesins such as aggregative adherence fimbriae. Currently, there is no effective prophylaxis and treatment available for EHEC infections in humans. Especially antibiotics are not indicated for treatment as they may induce Stx production, thus worsening the symptoms. Alternative therapeutics are therefore desperately needed. We tested the probiotic Escherichia coli strain Nissle 1917 (EcN) for antagonistic effects on two O104:H4 EHEC isolates from the 2011 outbreak and on the classical O157:H7 EHEC strain EDL933. These tests included effects on adherence, growth, and Stx production in monoculture and co-culture together with EcN. The inoculum of each co-culture contained EcN and the respective EHEC strain either at a ratio of 1:1 or 10:1 (EcN:EHEC). Adhesion of EHEC strains to Caco-2 cells and to the mucin-producing LS-174T cells was reduced significantly in co-culture with EcN at the 1:1 ratio and very dramatically at the 10:1 ratio. This inhibitory effect of EcN on EHEC adherence was most likely not due to occupation of adhesion sites on the epithelial cells, because in monocultures EcN adhered with much lower bacterial numbers than the EHEC strains. Both EHEC strains of serotype O104:H4 showed reduced growth in the presence of EcN (10:1 ratio). EHEC strain EDL933 grew in co-culture with EcN only during the first 2h of incubation. Thereafter, EHEC counts declined. At 24h, the numbers of viable EDL933 was at or slightly below the numbers at the time of inoculation. The amount of Stx2 after 24h co-incubation with EcN (EcN:EHEC ratio 10:1) was for all 3 EHEC strains tested significantly reduced in comparison to EHEC monocultures. Obviously, EcN shows very efficient antagonistic activity on

  2. Prevalence and Characterization of Non-O157 Shiga Toxin-Producing Escherichia coli Isolates from Commercial Ground Beef in the United States▿ †

    PubMed Central

    Bosilevac, Joseph M.; Koohmaraie, Mohammad

    2011-01-01

    Escherichia coli O157:H7 is a Shiga toxin (stx)-producing E. coli (STEC) strain that has been classified as an adulterant in U.S. beef. However, numerous other non-O157 STEC strains are associated with diseases of various severities and have become an increasing concern to the beef industry, regulatory officials, and the public. This study reports on the prevalence and characterization of non-O157 STEC in commercial ground beef samples (n = 4,133) obtained from numerous manufacturers across the United States over a period of 24 months. All samples were screened by DNA amplification for the presence of Shiga toxin genes, which were present in 1,006 (24.3%) of the samples. Then, culture isolation of an STEC isolate from all samples that contained stx1 and/or stx2 was attempted. Of the 1,006 positive ground beef samples screened for stx, 300 (7.3% of the total of 4,133) were confirmed to have at least one strain of STEC present by culture isolation. In total, 338 unique STEC isolates were recovered from the 300 samples that yielded an STEC isolate. All unique STEC isolates were serotyped and were characterized for the presence of known virulence factors. These included Shiga toxin subtypes, intimin subtypes, and accessory virulence factors related to adherence (saa, iha, lifA), toxicity (cnf, subA, astA), iron acquisition (chuA), and the presence of the large 60-MDa virulence plasmid (espP, etpD, toxB, katP, toxB). The isolates were also characterized by use of a pathogenicity molecular risk assessment (MRA; based on the presence of various O-island nle genes). Results of this characterization identified 10 STEC isolates (0.24% of the 4,133 total) that may be considered a significant food safety threat, defined by the presence of eae, subA, and nle genes. PMID:21257806

  3. Comparison of O-antigen gene cluster from E. coli O157 from human and non-human strains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Shiga toxin-containing Escherichia coli O157:H7 (STEC O157:H7) is an important zoonotic pathogen which can be transmitted to humans by ingestion of contaminated water or food. Cattle are a common reservoir for STEC O157:H7. This microorganism may cause diarrhea, bloody diarrhea, and hemolytic-uremic...

  4. The CsgA and Lpp proteins affect motility and cell invasion in a strain of Escherichia coli O157:H7

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In Escherichia coli O157:H7 strain ATCC 43895, a guanine to thymine transversion in the csgD promoter created strain 43895OR. Strain 43895OR produces an abundant extracellular matrix rich in curli fibers, forms biofilm on solid surfaces, invades cultured epithelial cells, and is more virulent in a m...

  5. Investigation of carbon storage regulation network (csr genes) and phenotypic differences between acid sensitive and resistant Escherichia coli O157:H7 strains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: Escherichia coli O157:H7 and related serotype strains have previously been shown to vary in acid resistance, however, little is known about strain specific mechanisms of acid resistance. We examined sensitive and resistant E. coli strains to determine the effects of growth in minimal and...

  6. The CsgA and Lpp proteins affect HEp-2 cell invasion, motility, and biofilm formation in a strain of Escherichia coli O157:H7

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In Escherichia coli O157:H7 strain ATCC 43895, a guanine to thymine transversion in the csgD promoter created strain 43895OR. Strain 43895OR produces an abundant extracellular matrix rich in curli fibers, forms biofilm on solid surfaces, invades cultured epithelial cells, and is more virulent in mic...

  7. Isolation of Escherichia coli O157:H7 from some Egyptian foods.

    PubMed

    Abdul-Raouf, U M; Ammar, M S; Beuchat, L R

    1996-04-01

    A survey was done in middle Egypt to determine if Escherichia coli O157:H7 was present in 175 samples of raw ground beef, chicken, lamb and unpasteurized milk. The pathogen was detected in 3 of 50 (6%) beef samples, 2 of 50 (4%) chicken samples, 1 of 25 (4%) lamb samples and 3 of 50 (6%) milk samples obtained from slaughterhouses, supermarkets and farmer's homes. PMID:8796444

  8. Phylogeny of Shiga toxin-producing Escherichia coli O157 isolated from cattle and clinically ill humans

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cattle are a major reservoir for Shiga toxin-producing Escherichia coli O157 (STEC O157) and harbor multiple genetic subtypes that do not all associate with human disease. STEC O157 evolved from an E. coli O55:H7 progenitor, however, a lack of genome sequence has hindered investigations on the dive...

  9. Methods for detection, isolation, and identification of Non-O157 shiga toxin-producing Escherichia coli

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Non-O157 Shiga toxin producing E. coli (STEC) have been increasingly associated with human infections in the U.S. and worldwide, and it is estimated that in the U.S. non-O157 STEC cause more than twice the number of infections overall compared to STEC O157:H7. The Centers for Disease Control and Pr...

  10. Non-O157 Shiga toxin-producing Escherichia coli

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Shiga toxin-producing Escherichia coli (STEC) O157:H7 is a leading cause of food-borne illness in the United States; however, recent reports have shown that non-O157 STEC serogroups contribute to more illnesses than O157:H7. Illness caused by non-O157 STEC strains are generally less severe than tho...

  11. Differences in inactivation of Escherichia coli O157:H7 strains in ground beef following repeated high pressure processing treatments and cold storage.

    PubMed

    Zhou, Yijing; Karwe, Mukund V; Matthews, Karl R

    2016-09-01

    High pressure processing (HPP) is a safe non-thermal processing method to effectively improve food safety. In this study, HPP treatment followed by cold storage was investigated to reduce Escherichia coli O157:H7 in ground beef. Experiments were conducted using ground beef contaminated with six E. coli O157:H7 strains one at a time or as a cocktail. Control and inoculated ground beef samples were HPP at 25 °C, 35 °C, and 45 °C, at 400 MPa and pre-determined number of pressure cycles totaling a holding time of 15 min. Optimum HPP parameters were 25 °C, 400 MPa at five pressure cycles of 3 min each which achieved a 5-log reduction of E. coli O157:H7 in ground beef. Storing HPP processed ground beef at 4 °C or -20 °C further decreased (P < 0.05) the E. coli O157:H7 population. An effective HPP treatment (5-log reduction) was developed that could be used post-processing to reduce the risk associated with E. coli O157:H7 contamination in ground beef. PMID:27217352

  12. Coculture of Escherichia coli O157:H7 with a Nonpathogenic E. coli Strain Increases Toxin Production and Virulence in a Germfree Mouse Model

    PubMed Central

    Goswami, Kakolie; Chen, Chun; Xiaoli, Lingzi; Eaton, Kathryn A.

    2015-01-01

    Escherichia coli O157:H7 is a notorious foodborne pathogen due to its low infectious dose and the disease symptoms it causes, which include bloody diarrhea and severe abdominal cramps. In some cases, the disease progresses to hemorrhagic colitis (HC) and hemolytic uremic syndrome (HUS), due to the expression of one or more Shiga toxins (Stx). Isoforms of Stx, including Stx2a, are encoded within temperate prophages. In the presence of certain antibiotics, phage induction occurs, which also increases the expression of toxin genes. Additionally, increased Stx2 accumulation has been reported when O157:H7 was cocultured with phage-susceptible nonpathogenic E. coli. This study characterized an E. coli O157:H7 strain, designated PA2, that belongs to the hypervirulent clade 8 cluster. Stx2a levels after ciprofloxacin induction were lower for PA2 than for the prototypical outbreak strains Sakai and EDL933. However, during coculture with the nonpathogenic strain E. coli C600, PA2 produced Stx2a levels that were 2- to 12-fold higher than those observed during coculture with EDL933 and Sakai, respectively. Germfree mice cocolonized by PA2 and C600 showed greater kidney damage, increased Stx2a accumulation in feces, and more visible signs of disease than mice given PA2 or C600 alone. These data suggest one mechanism by which microorganisms associated with the colonic microbiota could enhance the virulence of E. coli O157:H7, particularly a subset of clade 8 strains. PMID:26259815

  13. Coculture of Escherichia coli O157:H7 with a Nonpathogenic E. coli Strain Increases Toxin Production and Virulence in a Germfree Mouse Model.

    PubMed

    Goswami, Kakolie; Chen, Chun; Xiaoli, Lingzi; Eaton, Kathryn A; Dudley, Edward G

    2015-11-01

    Escherichia coli O157:H7 is a notorious foodborne pathogen due to its low infectious dose and the disease symptoms it causes, which include bloody diarrhea and severe abdominal cramps. In some cases, the disease progresses to hemorrhagic colitis (HC) and hemolytic uremic syndrome (HUS), due to the expression of one or more Shiga toxins (Stx). Isoforms of Stx, including Stx2a, are encoded within temperate prophages. In the presence of certain antibiotics, phage induction occurs, which also increases the expression of toxin genes. Additionally, increased Stx2 accumulation has been reported when O157:H7 was cocultured with phage-susceptible nonpathogenic E. coli. This study characterized an E. coli O157:H7 strain, designated PA2, that belongs to the hypervirulent clade 8 cluster. Stx2a levels after ciprofloxacin induction were lower for PA2 than for the prototypical outbreak strains Sakai and EDL933. However, during coculture with the nonpathogenic strain E. coli C600, PA2 produced Stx2a levels that were 2- to 12-fold higher than those observed during coculture with EDL933 and Sakai, respectively. Germfree mice cocolonized by PA2 and C600 showed greater kidney damage, increased Stx2a accumulation in feces, and more visible signs of disease than mice given PA2 or C600 alone. These data suggest one mechanism by which microorganisms associated with the colonic microbiota could enhance the virulence of E. coli O157:H7, particularly a subset of clade 8 strains. PMID:26259815

  14. Production and characterization of monoclonal antibodies specific for the lipopolysaccharide of Escherichia coli O157.

    PubMed Central

    Westerman, R B; He, Y; Keen, J E; Littledike, E T; Kwang, J

    1997-01-01

    Identification of the O157 antigen is an essential part of the detection of Escherichia coli O157:H7, which is recognized as a major etiologic agent of hemorrhagic colitis. However, polyclonal antibodies produced against E. coli O157:H7 lipopolysaccharide (LPS) may react with several other bacteria including Brucella abortus, Brucella melitensis, Yersinia enterocolitica O9, Escherichia hermannii, and Stenotrophomonas maltophilia. We produced eight monoclonal antibodies (MAbs) specific for the LPS of E. coli O157. Western blots (immunoblots) of both the phenol phase (smooth) and the aqueous phase (rough) of hot phenol-water-purified LPS indicated that three of the MAbs were specific for the O antigen and five were reactive with the LPS core. The eight MAbs could be further differentiated by their reactivities to Salmonella O30 LPS (group N), which is reported to be identical to the E. coli O157 antigen. All eight MAbs reacted strongly to all of the 64 strains of E. coli O157 tested, which included 47 isolates of O157:H7 and 17 other O157 strains. None of the eight MAbs cross-reacted with any of the 38 other E. coli serotypes tested, which consisted of 29 different O-antigen serotypes, or with 38 strains (22 genera) of non-E. coli gram-negative enteric bacteria. PMID:9041412

  15. Complete genome sequence of SS52, a strain of Escherichia coli O157:H7 recovered from supershedder cattle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Shiga toxin-producing Escherichia coli O157:H7 cause foodborne infections and cattle are the primary reservoir. Some animals, known as supershedders, excrete orders of magnitude more E. coli O157:H7 in the feces than normal. We here report the complete genome sequence of the SS52 supershedder stra...

  16. Virulence characterization of non-O157 Shiga toxin-producing Escherichia coli isolates from food, humans and animals.

    PubMed

    Shen, Jinling; Rump, Lydia; Ju, Wenting; Shao, Jingdong; Zhao, Shaohua; Brown, Eric; Meng, Jianghong

    2015-09-01

    A total of 359 non-O157 STEC isolates from food, humans and animals were examined for serotypes, Shiga toxin subtypes and intimin subtypes. Isolates solely harboring stx2 from the three sources were selected for Vero cell cytotoxicity test. stx subtypes in eae negative isolates were more diverse than in eae positive isolates primarily carrying stx2a. Four eae subtypes (eaeβ,eaeε1,eaeγ1 and eaeγ2/θ) were observed and correlated with serotypes and flagella. Food isolates showed more diverse serotypes, virulence factors and cell cytotoxicities than human isolates. Some isolates from produce belonged to serotypes that have been implicated in human diseases, carried stx2a or/and stx2dact and exhibited high cell cytotoxicity similar to human isolates. This indicates that foods can be contaminated with potentially pathogenic STEC isolates that may cause human diseases. Given the increased produce consumption and growing burden of foodborne outbreaks due to produce, produce safety should be given great importance. PMID:25998811

  17. Disinfectant and antibiotic susceptibility profiles of Escherichia coli O157:H7 strains from cattle carcasses, feces, and hides and ground beef from the United States

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The disinfectant and antibiotic susceptibility profiles of 344 Escherichia coli O157:H7 isolates from cattle feces, hide, carcass, and ground beef from different areas of the United States were determined. Overall, a low incidence of antibiotic resistance was observed (14%). The highest-incidence ...

  18. Molecular Characterization of Human Atypical Sorbitol-Fermenting Enteropathogenic Escherichia coli O157 Reveals High Diversity.

    PubMed

    Kossow, Annelene; Zhang, Wenlan; Bielaszewska, Martina; Rhode, Sophie; Hansen, Kevin; Fruth, Angelika; Rüter, Christian; Karch, Helge; Mellmann, Alexander

    2016-05-01

    Alongside the well-characterized enterohemorrhagic Escherichia coli (EHEC) O157:H7, serogroup O157 comprises sorbitol-fermenting typical and atypical enteropathogenic E. coli (EPEC/aEPEC) strains that carry the intimin-encoding gene eae but not Shiga toxin-encoding genes (stx). Since little is known about these pathogens, we characterized 30 clinical isolates from patients with hemolytic uremic syndrome (HUS) or uncomplicated diarrhea with respect to their flagellin gene (fliC) type and multilocus sequence type (MLST). Moreover, we applied whole-genome sequencing (WGS) to determine the phylogenetic relationship with other eae-positive EHEC serotypes and the composition of the rfbO157 region. fliC typing resulted in five fliC types (H7, H16, H34, H39, and H45). Isolates of each fliC type shared a unique ST. In comparison to the 42 HUS-associated E. coli (HUSEC) strains, only the stx-negative isolates with fliCH7 shared their ST with EHEC O157:H7/H(-) strains. With the exception of one O157:H(-) fliCH16 isolate, HUS was exclusively associated with fliCH7. WGS corroborated the separation of the fliCH7 isolates, which were closely related to the EHEC O157:H7/H(-) isolates, and the diverse group of isolates exhibiting different fliC types, indicating independent evolution of the different serotypes. This was also supported by the heterogeneity within the rfbO157 region that exhibited extensive recombinations. The genotypic subtypes and distribution of clinical symptoms suggested that the stx-negative O157 strains with fliCH7 were originally EHEC strains that lost stx The remaining isolates form a distinct and diverse group of atypical EPEC isolates that do not possess the full spectrum of virulence genes, underlining the importance of identifying the H antigen for clinical risk assessment. PMID:26984976

  19. Molecular Insights into the Phenotypic Divergence in Natural Curli Variants of Escherichia coli O157:H7

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Escherichia coli O157:H7 (EcO157) causes severe disease including hemolytic uremic syndrome and contributes significantly to human infections and outbreaks. We previously reported that natural curli variants isolated from the same strain display distinct phenotypic differences: curli-deficient varia...

  20. Outbreak Investigation: STEC O157

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The standard microbiological methods used to isolate Escherichia coli O157:H7 from human stool are frequently inadequate for isolation of this same organism from environmental samples. This paper describes the laboratory isolation of this pathogen from four environmental samples collected as part o...

  1. Bison and bovine rectoanal junctions exhibit similar cellular architecture and Escherichia coli O157 adherence patterns

    PubMed Central

    2013-01-01

    Background Escherichia coli O157 (E. coli O157) has been isolated from bison retail meat, a fact that is important given that bison meat has been implicated in an E. coli O157-multistate outbreak. In addition, E. coli O157 has also been isolated from bison feces at slaughter and on farms. Cattle are well documented as E. coli O157 reservoirs, and the primary site of E. coli O157 persistence in such reservoirs is the rectoanal junction (RAJ), located at the distal end of the bovine gastrointestinal tract. Since bison and cattle share many genetic similarities manifested as common lineage, susceptibility to infection and the nature of immune responses to infectious agents, we decided to evaluate whether the RAJ of these animals were comparable both in terms of cellular architecture and as sites for adherence of E. coli O157. Specifically, we compared the histo-morphologies of the RAJ and evaluated the E. coli O157 adherence characteristics to the RAJ squamous epithelial (RSE) cells, from these two species. Results We found that the RAJ of both bison and cattle demonstrated similar distribution of epithelial cell markers villin, vimentin, cytokeratin, E-cadherin and N-cadherin. Interestingly, N-cadherin predominated in the stratified squamous epithelium reflecting its proliferative nature. E. coli O157 strains 86–24 SmR and EDL 933 adhered to RSE cells from both animals with similar diffuse and aggregative patterns, respectively. Conclusion Our observations further support the fact that bison are likely ‘wildlife’ reservoirs for E. coli O157, harboring these bacteria in their gastrointestinal tract. Our results also extend the utility of the RSE-cell assay, previously developed to elucidate E. coli O157-cattle RAJ interactions, to studies in bison, which are warranted to determine whether these observations in vitro correlate with those occurring in vivo at the RAJ within the bison gastrointestinal tract. PMID:24373611

  2. Contamination of bovine carcasses and abattoir environment by Escherichia coli O157:H7 in Istanbul.

    PubMed

    Gun, H; Yilmaz, A; Turker, S; Tanlasi, A; Yilmaz, H

    2003-08-01

    The aim of this study was to investigate contamination of carcasses and abattoir environment with Escherichia coli O157:H7. Five abattoirs in Istanbul were visited between January 2000 and April 2001. During visits, sampling was performed and a total of 330 cattle were selected. Cattle were examined for the presence of faeces on the hide (abdomen and legs) before slaughter. The swabs from the carcasses and environmental samples (abattoir floor, benches including conveyors, knives, aprons, saws, hooks, hands) were taken at the abattoir immediately after slaughter using sterile cotton swabs. A sample from the wash water of the abattoir was also taken. Preenrichment, immunomagnetic separation and CT-SMAC agar were used for the isolation. The reaction of the isolates with anti-O157 and H7 antisera were also analysed. Twelve strains (3.6%) of E. coli O157 were isolated from the cattle carcasses and eight (2.4%) of them gave positive reaction with anti-H:7. Six strains of E. coli O157 were isolated from the environmental samples and all strains were positive for H7. The number of E. coli O157H:7 strains isolated from the environmental samples was two from the knife, two from the hands, one from the apron and one from the floor. No E. coli O157 was isolated from the abattoir water. PMID:12810296

  3. Detection of CMY-2 AmpC β-lactamase-producing enterohemorrhagic Escherichia coli O157:H7 from outbreak strains in a nursery school in Japan.

    PubMed

    Kameyama, Mitsuhiro; Yabata, Junko; Nomura, Yasuharu; Tominaga, Kiyoshi

    2015-07-01

    In 2013, an outbreak of enterohemorrhagic Escherichia coli (EHEC) O157:H7 occurred in a nursery school in Japan. The outbreak affected 12 school children and five members of their families. All 17 isolates obtained from these individuals were found to be clonal, as determined by pulsed-field gel electrophoresis analysis and multilocus variable number tandem repeat analysis. The antimicrobial susceptibility profiles of the isolates to 20 drugs were examined, with three isolates showing resistance to the extended-spectrum cephalosporins (ESC) and cephamycin, including cefotaxime, ceftazidime, and cefminox. The resistant isolates carried the blaCMY-2 AmpC β-lactamase gene. It is proposed that the ESC-resistant EHEC O157:H7 isolates might have acquired the resistance plasmid encoding the blaCMY-2 gene during human to human infection in the nursery school. PMID:25835518

  4. Bacteriophage-based rapid and sensitive detection of Escherichia coli O157:H7 isolates from ground beef

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We investigated efficacy of bacteriophage-based detection technology to detect Escherichia coli O157:H7 from ground beef. The assay involved 8 h enrichment of cold stressed beef samples in presence of antimicrobials followed by capture of the pathogen on O157:H7-specific immunomagnetic beads and sp...

  5. Irradiation Sensitivity of Planktonic and Biofilm-Associated Escherichia coli O157:H7 Isolates is Influenced by Culture Conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Escherichia coli O157:H7 is an important human pathogen which is known to form biofilms that are relatively resistant to chemical sanitizing treatments. Ionizing radiation effectively inactivates E. coli O157:H7 on a variety of foods and contact surfaces, but the relative efficacy of the process aga...

  6. Isolation of Campylobacter from feral swine (Sus scrofa) on the ranch associated with the 2006 Escherichia coli O157:H7 spinach outbreak investigation in California

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We report the isolation of Campylobacter species from the same population of feral swine that was investigated in San Benito County, California during the 2006 spinach-related Escherichia coli O157:H7 outbreak. This is the first survey of Campylobacter in a free-ranging feral swine population in the...

  7. Acid resistance and molecular characterization of Escherichia coli O157:H7 and different Non-O157 shiga toxin-producing E. coli serogroups

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this study was to compare the acid resistance (AR) of non-O157 Shiga toxin-producing Escherichia coli (STEC) strains belonging to serogroups O26, O45, O103, O104, O111, O121, and O145 with O157:H7 STEC isolated from various sources in 400 mM acetic acid solutions (AAS) at pH 3.2 and...

  8. Acid Resistance and molecular characterization of Escherichia coli O157:H7 and different non-O157 Shiga toxin-producing E. coli serogroups

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this study was to compare the acid resistance (AR) of seven non-O157 Shiga toxin-producing E. coli (STEC) strains belonging to serogroups O26, O45, O103, O104, O111, O121 and O145 with O157:H7 STEC isolated from various sources in 400 mM acetic acid solutions (AAS) at pH 3.2 and 30°...

  9. Isolation of Escherichia coli 0157:H7 strain from fecal samples of zoo animal.

    PubMed

    Mohammed Hamzah, Aseel; Mohammed Hussein, Aseel; Mahmoud Khalef, Jenan

    2013-01-01

    The isolation and characterization of Escherichia coli O157:H7 strains from 22 out of 174 fecal samples from petting zoo animals representing twenty-two different species (camel, lion, goats, zebra, bear, baboon monkey, Siberian monkey, deer, elk, llama, pony, horses, fox, kangaroo, wolf, porcupine, chickens, tiger, ostrich, hyena, dogs, and wildcats) were investigated. One petting Al-Zawraa zoological society of Baghdad was investigated for E. coli O157:H7 over a 16-month period that spanned two summer and two autumn seasons. Variation in the occurrence of E. coli O157:H7-positive petting zoo animals was observed, with animals being culture positive only in the summer months but not in the spring, autumn, or winter. E. coli O157:H7 isolates were distinguished by agglutination with E. coli O157:H7 latex reagent (Oxoid), identified among the isolates, which showed that multiple E. coli strains were isolated from one petting zoo animal, in which a single animal simultaneously shed multiple E. coli strains; E. coli O157:H7 was isolated only by selective enrichment culture of 2 g of petting zoo animal feces. In contrast, strains other than O157:H7 were cultured from feces of petting zoo animals without enrichment. PMID:24489514

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

    PubMed Central

    Mohammed Hamzah, Aseel; Mohammed Hussein, Aseel; Mahmoud Khalef, Jenan

    2013-01-01

    The isolation and characterization of Escherichia coli O157:H7 strains from 22 out of 174 fecal samples from petting zoo animals representing twenty-two different species (camel, lion, goats, zebra, bear, baboon monkey, Siberian monkey, deer, elk, llama, pony, horses, fox, kangaroo, wolf, porcupine, chickens, tiger, ostrich, hyena, dogs, and wildcats) were investigated. One petting Al-Zawraa zoological society of Baghdad was investigated for E. coli O157:H7 over a 16-month period that spanned two summer and two autumn seasons. Variation in the occurrence of E. coli O157:H7-positive petting zoo animals was observed, with animals being culture positive only in the summer months but not in the spring, autumn, or winter. E. coli O157:H7 isolates were distinguished by agglutination with E. coli O157:H7 latex reagent (Oxoid), identified among the isolates, which showed that multiple E. coli strains were isolated from one petting zoo animal, in which a single animal simultaneously shed multiple E. coli strains; E. coli O157:H7 was isolated only by selective enrichment culture of 2 g of petting zoo animal feces. In contrast, strains other than O157:H7 were cultured from feces of petting zoo animals without enrichment. PMID:24489514

  11. Evaluation of Hha and Hha SepB Mutant Strains of Escherichia coli O157:H7 as Bacterins for Reducing E. coli O157:H7 Shedding in Cattle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Escherichia coli O157:H7 colonizes cattle intestines by using locus of enterocyte effacement (LEE)-encoded proteins. Induction of systemic immune response against LEE-encoded proteins, therefore, will prove effective in reducing E. coli O157:H7 colonization in cattle. Previous studies have demonstra...

  12. Growth of Stressed Strains of Four Non-O157 Shiga Toxin-Producing Escherichia coli Serogroups in Five Enrichment Broths.

    PubMed

    Verhaegen, Bavo; De Reu, Koen; Heyndrickx, Marc; Van Damme, Inge; De Zutter, Lieven

    2015-11-01

    The purpose of this study was to evaluate (i) the behavior of several strains of non-O157 Shiga toxin-producing Escherichia coli (STEC) serogroups (O26, O103, O111, and O145) exposed to different stress conditions and (ii) the growth dynamics of stressed and nonstressed non-O157 STEC cells in five enrichment media. STEC strains were exposed to acid, cold, and freeze stresses. Lethal and sublethal injuries were determined by plating in parallel on selective and nonselective agar media. Freeze stress (8 days, 20°C) caused the most lethal (95.3% ± 2.5%) injury, as well as the most sublethal (89.1% ± 8.8%) injury in the surviving population. Growth of stressed and nonstressed pure cultures of non-O157 STEC on modified tryptic soy broth, buffered peptone water (BPW), BPW with sodium pyruvate, Brila, and STEC enrichment broth (SEB) was determined using total viable counts. To compare growth capacities, growth after 7 and 24 h of enrichment was measured; lag phases and maximum growth rates were also calculated. In general, growth on BPW resulted in a short lag phase followed by a high maximum growth rate during the enrichment of all tested strains when using all three stress types. Furthermore, BPW ensured the highest STEC count after 7 h of growth. Supplementing the medium with sodium pyruvate did not improve the growth dynamics. The two selective media, Brila and SEB, were less efficient than BPW, but Brila's enrichment performance was remarkably better than that of SEB. This study shows that irrespective of the effect of background flora, BPW is still recommended for resuscitation of non-O157 STEC. PMID:26555518

  13. Escherichia coli O157:H7: Animal Reservoir and Sources of Human Infection

    PubMed Central

    Ferens, Witold A.

    2011-01-01

    Abstract This review surveys the literature on carriage and transmission of enterohemorrhagic Escherichia coli (EHEC) O157:H7 in the context of virulence factors and sampling/culture technique. EHEC of the O157:H7 serotype are worldwide zoonotic pathogens responsible for the majority of severe cases of human EHEC disease. EHEC O157:H7 strains are carried primarily by healthy cattle and other ruminants, but most of the bovine strains are not transmitted to people, and do not exhibit virulence factors associated with human disease. Prevalence of EHEC O157:H7 is probably underestimated. Carriage of EHEC O157:H7 by individual animals is typically short-lived, but pen and farm prevalence of specific isolates may extend for months or years and some carriers, designated as supershedders, may harbor high intestinal numbers of the pathogen for extended periods. The prevalence of EHEC O157:H7 in cattle peaks in the summer and is higher in postweaned calves and heifers than in younger and older animals. Virulent strains of EHEC O157:H7 are rarely harbored by pigs or chickens, but are found in turkeys. The bacteria rarely occur in wildlife with the exception of deer and are only sporadically carried by domestic animals and synanthropic rodents and birds. EHEC O157:H7 occur in amphibian, fish, and invertebrate carriers, and can colonize plant surfaces and tissues via attachment mechanisms different from those mediating intestinal attachment. Strains of EHEC O157:H7 exhibit high genetic variability but typically a small number of genetic types predominate in groups of cattle and a farm environment. Transmission to people occurs primarily via ingestion of inadequately processed contaminated food or water and less frequently through contact with manure, animals, or infected people. PMID:21117940

  14. Escherichia coli O157 infection associated with a petting zoo.

    PubMed Central

    Heuvelink, A. E.; van Heerwaarden, C.; Zwartkruis-Nahuis, J. T. M.; van Oosterom, R.; Edink, K.; van Duynhoven, Y. T. H. P.; de Boer, E.

    2002-01-01

    A young child was admitted to hospital with haemolytic-uraemic syndrome caused by infection with a Shiga toxin 2-producing strain of Escherichia coli (STEC) O157. Five days before he became ill, the child had visited a small petting zoo. STEC O157 strains were isolated from faecal samples from goats and sheep housed on the farm. The human and the animal isolates were indistinguishable by molecular subtyping. The petting zoo voluntarily closed temporarily to prevent further cases of infection. Two out of 11 other, randomly selected petting zoos (including one deer park) visited subsequently, tested positive. Furthermore, during the study period there was one more notification of STEC O157 infection possibly linked with a farm visit. Although STEC O157 was indeed found in the petting zoo associated with this patient, transmission through animal contact could not be confirmed because the human isolate was not available for subtyping. The case study and the results of the other on-farm investigations highlight the risk of acquiring severe zoonotic infections during visits to petting zoos. PMID:12403105

  15. Escherichia coli O157 infection associated with a petting zoo.

    PubMed

    Heuvelink, A E; van Heerwaarden, C; Zwartkruis-Nahuis, J T M; van Oosterom, R; Edink, K; van Duynhoven, Y T H P; de Boer, E

    2002-10-01

    A young child was admitted to hospital with haemolytic-uraemic syndrome caused by infection with a Shiga toxin 2-producing strain of Escherichia coli (STEC) O157. Five days before he became ill, the child had visited a small petting zoo. STEC O157 strains were isolated from faecal samples from goats and sheep housed on the farm. The human and the animal isolates were indistinguishable by molecular subtyping. The petting zoo voluntarily closed temporarily to prevent further cases of infection. Two out of 11 other, randomly selected petting zoos (including one deer park) visited subsequently, tested positive. Furthermore, during the study period there was one more notification of STEC O157 infection possibly linked with a farm visit. Although STEC O157 was indeed found in the petting zoo associated with this patient, transmission through animal contact could not be confirmed because the human isolate was not available for subtyping. The case study and the results of the other on-farm investigations highlight the risk of acquiring severe zoonotic infections during visits to petting zoos. PMID:12403105

  16. Antibacterial effects of natural tenderizing enzymes on different strains of Escherichia coli O157:H7 and Listeria monocytogenes on beef.

    PubMed

    Eshamah, Hanan; Han, Inyee; Naas, Hesham; Acton, James; Dawson, Paul

    2014-04-01

    This study determined the efficacy of actinidin and papain on reducing Listeria monocytogenes and three mixed strains of Escherichia coli O157:H7 populations on beef. The average reduction of E. coli O157:H7 was greater than that of L. monocytogenes and higher concentrations of either protease yielded greater reduction in bacterial populations. For instance, actinidin at 700 mg/ml significantly (p≤0.05) reduced the population of L. monocytogenes by 1.49 log cfu/ml meat rinse after 3h at 25 & 35 °C, and by 1.45 log cfu/ml rinse after 24h at 5 °C, while the same actinidin concentration significantly reduced the populations of three mixed strains of E. coli O157:H7 by 1.81 log cfu/ml rinse after 3h at 25 & 35 °C, and 1.94 log cfu/ml rinse after 24h at 5 °C. These findings suggest that, in addition to improving the sensory attributes of beef, proteolytic enzymes can enhance meat safety when stored at suitable temperatures. PMID:24447905

  17. Isolation of Multidrug-Resistant Escherichia coli O157 from Goats in the Somali Region of Ethiopia: A Cross-Sectional, Abattoir-Based Study.

    PubMed

    Dulo, Fitsum; Feleke, Aklilu; Szonyi, Barbara; Fries, Reinhard; Baumann, Maximilian P O; Grace, Delia

    2015-01-01

    Toxigenic Escherichia coli (E. coli) are an important cause of gastroenteritis in developing countries. In Ethiopia, gastroenteritis due to food-borne disease is a leading cause of death. Yet, there is no surveillance for E. coli O157 and little is known about the carriage of this pathogen in Ethiopia's livestock. This study aimed to assess the prevalence and levels of antimicrobial resistance of E. coli O157 in goat meat, feces, and environmental samples collected at a large abattoir in the Somali region of Ethiopia. The samples were enriched in modified tryptone broth containing novobiocin, and plated onto sorbitol MacConkey agar. Isolates were confirmed using indole test and latex agglutination. Antimicrobial susceptibility testing was conducted using the disk diffusion method. A total of 235 samples, including 93 goat carcass swabs, 93 cecal contents, 14 water, 20 hand, and 15 knife swabs were collected. Overall, six (2.5%) samples were contaminated with E. coli O157 of which two (2.1%) were isolated from cecal contents, three (3.2%) from carcass swabs, and one (7.1%) from water. All isolates were resistant to at least two of the 18 antimicrobials tested. Two isolates (33.3%) were resistant to more than five antimicrobials. Abattoir facilities and slaughter techniques were conducive to carcass contamination. This study highlights how poor hygiene and slaughter practice can result in contaminated meat, which is especially risky in Ethiopia because of the common practice of eating raw meat. We detect multi-resistance to drugs not used in goats, suggesting that drugs used to treat human infections may be the originators of antimicrobial resistance in livestock in this ecosystem. The isolation of multidrug-resistant E. coli O157 from goats from a remote pastoralist system highlights the need for global action on regulating and monitoring antimicrobial use in both human and animal populations. PMID:26561414

  18. Isolation of Multidrug-Resistant Escherichia coli O157 from Goats in the Somali Region of Ethiopia: A Cross-Sectional, Abattoir-Based Study

    PubMed Central

    Dulo, Fitsum; Feleke, Aklilu; Szonyi, Barbara; Fries, Reinhard; Baumann, Maximilian P. O.; Grace, Delia

    2015-01-01

    Toxigenic Escherichia coli (E. coli) are an important cause of gastroenteritis in developing countries. In Ethiopia, gastroenteritis due to food-borne disease is a leading cause of death. Yet, there is no surveillance for E. coli O157 and little is known about the carriage of this pathogen in Ethiopia’s livestock. This study aimed to assess the prevalence and levels of antimicrobial resistance of E. coli O157 in goat meat, feces, and environmental samples collected at a large abattoir in the Somali region of Ethiopia. The samples were enriched in modified tryptone broth containing novobiocin, and plated onto sorbitol MacConkey agar. Isolates were confirmed using indole test and latex agglutination. Antimicrobial susceptibility testing was conducted using the disk diffusion method. A total of 235 samples, including 93 goat carcass swabs, 93 cecal contents, 14 water, 20 hand, and 15 knife swabs were collected. Overall, six (2.5%) samples were contaminated with E. coli O157 of which two (2.1%) were isolated from cecal contents, three (3.2%) from carcass swabs, and one (7.1%) from water. All isolates were resistant to at least two of the 18 antimicrobials tested. Two isolates (33.3%) were resistant to more than five antimicrobials. Abattoir facilities and slaughter techniques were conducive to carcass contamination. This study highlights how poor hygiene and slaughter practice can result in contaminated meat, which is especially risky in Ethiopia because of the common practice of eating raw meat. We detect multi-resistance to drugs not used in goats, suggesting that drugs used to treat human infections may be the originators of antimicrobial resistance in livestock in this ecosystem. The isolation of multidrug-resistant E. coli O157 from goats from a remote pastoralist system highlights the need for global action on regulating and monitoring antimicrobial use in both human and animal populations. PMID:26561414

  19. Escherichia coli O157 in ground beef from local retail markets in Pachuca, Mexico.

    PubMed

    Gómez-Aldapa, Carlos A; Díaz-Cruz, Claudio A; Cerna-Cortes, Jorge F; Torres-Vitela, M Del Refugio; Villarruel-López, Angelica; Rangel-Vargas, Esmeralda; Castro-Rosas, Javier

    2013-04-01

    Escherichia coli O157 strains have been recognized as pathogenic bacteria, of which raw beef is a known vehicle. An evaluation was done of the presence of E. coli O157 in ground beef from local retail markets in Pachuca, Hidalgo State, Mexico. A total of 120 ground beef samples (500 g) were tested for E. coli O157 by simultaneous application of the U. S. Department of Agriculture, Food Safety and Inspection Service (FSIS)'s Microbiology Laboratory Guidebook culture procedure 5.05, and two commercial kits, Reveal for E. coli O157:H7 and Visual Immunoprecipitate Assay (VIP) Gold for enterohemorrhagic E. coli. Two incubation times (8 and 20 h) were used with the commercial kits. Presence of stx1, stx2, and eaeA loci was determined by multiplex PCR. Of 360 subsamples (120 per procedure), 12 samples were found to be E. coli O157 positive by the FSIS culture method. With VIP, 73 subsamples were presumptive positive after 8 h of enrichment, and 60 were presumptive positive after 20 h of enrichment. Of these, only 6 (8 h) and 8 (20 h) subsamples were confirmed true positives with the FSIS method. With Reveal, 60 subsamples were presumptive positive after 8 h of enrichment and 50 were presumptive positive after 20 h of enrichment. Of these, only 6 (8 h) and 8 (20 h) subsamples were confirmed as true positives with the FSIS method. A total of 57 E. coli O157:H7 and 21 E. coli O157 strains were isolated. None of the O157 or O157:H7 strains had stx1 or stx2 loci, and only one had the eaeA locus. To our knowledge, this is the first report of the presence of E. coli O157 in commercial ground beef from Mexico, and the first report of isolation of a large number of stx-negative E. coli O157 and E. coli O157:H7 strains in Mexico. PMID:23575133

  20. Support Vector Machine applied to predict the zoonotic potential of E. coli O157 cattle isolates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Methods based on sequence data analysis facilitate the tracking of disease outbreaks, allow relationships between strains to be reconstructed and virulence factors to be identified. However, these methods are used postfactum after an outbreak has happened. Here, we show that support vector machine a...

  1. Disinfectant and Antimicrobial Susceptibility Profiles of the Big Six Non-O157 Shiga Toxin-Producing Escherichia coli Strains from Food Animals and Humans.

    PubMed

    Beier, Ross C; Franz, Eelco; Bono, James L; Mandrell, Robert E; Fratamico, Pina M; Callaway, Todd R; Andrews, Kathleen; Poole, Toni L; Crippen, Tawni L; Sheffield, Cynthia L; Anderson, Robin C; Nisbet, David J

    2016-08-01

    The disinfectant and antimicrobial susceptibility profiles of 138 non-O157 Shiga toxin-producing Escherichia coli strains (STECs) from food animals and humans were determined. Antimicrobial resistance (AMR) was moderate (39.1% of strains) in response to 15 antimicrobial agents. Animal strains had a lower AMR prevalence (35.6%) than did human strains (43.9%) but a higher prevalence of the resistance profile GEN-KAN-TET. A decreasing prevalence of AMR was found among animal strains from serogroups O45 > O145 > O121 > O111 > O26 > O103 and among human strains from serogroups O145 > O103 > O26 > O111 > O121 > O45. One animal strain from serogroups O121 and O145 and one human strain from serogroup O26 had extensive drug resistance. A high prevalence of AMR in animal O45 and O121 strains and no resistance or a low prevalence of resistance in human strains from these serogroups suggests a source other than food animals for human exposure to these strains. Among the 24 disinfectants evaluated, all strains were susceptible to triclosan. Animal strains had a higher prevalence of resistance to chlorhexidine than did human strains. Both animal and human strains had a similar low prevalence of low-level benzalkonium chloride resistance, and animal and human strains had similar susceptibility profiles for most other disinfectants. Benzyldimethylammonium chlorides and C10AC were the primary active components in disinfectants DC&R and P-128, respectively, against non-O157 STECs. A disinfectant FS512 MIC ≥ 8 μg/ml was more prevalent among animal O121 strains (61.5%) than among human O121 strains (25%), which may also suggest a source of human exposure to STEC O121 other than food animals. Bacterial inhibition was not dependent solely on pH but was correlated with the presence of dissociated organic acid species and some undissociated acids. PMID:27497123

  2. Effect of spinach cultivar and strain variation on survival of Escherichia coli O157:H7 on spinach leaves

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Introduction: Escherichia coli O157:H7 outbreaks of infections associated with the consumption of fresh produce have increased in recent years. Bacterial cell surface appendages such as curli and the spinach leaf structure topography influence pathogen attachment and subsequent survival on spinach ...

  3. The effects of free chlorine concentration, organic load, and exposure time on the inactivation of Salmonella, Escherichia coli O157:H7 and non-O157 STEC

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study evaluated the effects of free chlorine (FC) concentration, contact time, and organic load on the inactivation of Salmonella, E. coli O157:H7, and non-O157 STEC in suspension. Four strains each of Salmonella, E. coli O157:H7, or non-O157 STEC cells were inoculated separately or as a multi-...

  4. Analyses of the Red-Dry-Rough Phenotype of an Escherichia coli O157:H7 Strain and Its Role in Biofilm Formation and Resistance to Antibacterial Agents

    PubMed Central

    Uhlich, Gaylen A.; Cooke, Peter H.; Solomon, Ethan B.

    2006-01-01

    In a previous study, we identified Congo red-binding and -nonbinding phase variants of Escherichia coli serotype O157:H7 strain ATCC 43895. The Congo red-binding variant, strain 43895OR, produced a dry, aggregative colony that was similar to the red, dry, and rough (rdar) phenotype characteristic of certain strains of Salmonella. In contrast, variant 43895OW produced a smooth and white colony morphology. In this study, we show that, similar to rdar strains of Salmonella enterica serovar Typhimurium, strain 43895OR forms large aggregates in broth cultures, firm pellicles at the air-medium interface on glass, and dense biofilms on glass and polystyrene. However, unlike S. enterica serovar Typhimurium, strain 43895OR does not stain positive for cellulose production. When strain 43895OR was fixed on agar, scanning electron microscopy showed cells expressing extracellular matrix (ECM) containing curli fibers. Strain 43895OW was devoid of any ECM or curli fibers on agar but showed expression of curli fibers during attachment to glass. Strain 43895OR produced >4-fold-larger amounts of biofilm than strain 43895OW on polystyrene, glass, stainless steel, and Teflon; formation was >3-fold higher in rich medium than in nutrient-limited medium. Biofilm-associated cells of both strains showed statistically greater resistance (P < 0.05) to hydrogen peroxide and quaternary ammonium sanitizer than their respective planktonic cells. This study shows that the rdar phenotype of E. coli O157:H7 strain 43895OR is important in multicellular growth, biofilm formation, and resistance to sanitizers. However, the lack of cellulose production by strain 43895OR indicates important differences in the ECM composition compared to that of Salmonella. PMID:16597958

  5. Prevalence and geographical distribution of Escherichia coli O157 in India: a 10-year survey.

    PubMed

    Sehgal, Rakesh; Kumar, Yashwant; Kumar, Sunil

    2008-04-01

    Escherichia coli colonizes the human gastrointestinal tract and produces a variety of diseases. Escherichia coli O157 is one of the most important pathogenic strains reported from food-borne illnesses leading to enterohemorrhagic colitis. The National Salmonella and Escherichia Centre is a national reference centre for Salmonella and Escherichia for India; it receives samples from research laboratories, hospitals and institutions for serological identification. The present study is an epidemiological survey of E. coli O157 in different regions of India. The data are based on samples received from humans, food items, animals and the environment. A total of 17 093 isolates cultured from samples were received during the 10-year period of which 5678 were from human sources. Thirty (0.5%) human samples were positive for E. coli O157. A significantly high percentage of E. coli O157 were isolated from meat (0.9%, 13/1376), milk and milk products (1.8%, 10/553), seafood (8.4%, 16/190) and water (1.6%, 8/486). The isolates were found to be distributed among domestic and wild animals, and the maximum number of isolates of E. coli O157 was detected in samples received from coastal belt areas. Escherichia coli O157 is widely distributed among humans and animals, food and environment in different geographical regions of India. PMID:18321544

  6. Bison and bovine rectoanal junctions exhibit similar cellular architecture and Escherichia coli O157 adherence patterns

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Escherichia coli O157 (O157) is frequently isolated from bison retail meat, a fact that is important given that bison meat has also been implicated in an O157-multistate outbreak. In addition, O157 has also been isolated from bison feces at slaughter and on farms. Cattle are well documented as O15...

  7. Bacteriophage Isolated from Feedlot Cattle Can Reduce Escherichia coli O157:H7 Populations in Ruminant Gastrointestinal Tracts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Foodborne pathogenic bacteria, such as Escherichia coli O157:H7, can live undetected in the gut of food animals and be spread to humans via consumption of contaminated meat, direct animal contact, or water runoff into drinking and crop irrigation water supplies. Bacteriophages are viruses that prey...

  8. Prevalence and antimicrobial resistance profiles of Escherichia coli O157:H7 and Salmonella isolated from feedlot lambs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The present study examined the incidence of E. coli O157:H7 and Salmonella in feedlot lambs. Fifty-six feedlot lambs originating from eight different sheep farming operations were grouped in a single drylot pen, fed and managed as typical for a sheep feedlot in the southwestern United States. Feca...

  9. Nutritional basis for colonization resistance by human commensal Escherichia coli strains HS and Nissle 1917 against E. coli O157:H7 in the mouse intestine.

    PubMed

    Maltby, Rosalie; Leatham-Jensen, Mary P; Gibson, Terri; Cohen, Paul S; Conway, Tyrrell

    2013-01-01

    Escherichia coli is a single species consisting of many biotypes, some of which are commensal colonizers of mammals and others that cause disease. Humans are colonized on average with five commensal biotypes, and it is widely thought that the commensals serve as a barrier to infection by pathogens. Previous studies showed that a combination of three pre-colonized commensal E. coli strains prevents colonization of E. coli O157:H7 in a mouse model (Leatham, et al., 2010, Infect Immun 77: 2876-7886). The commensal biotypes included E. coli HS, which is known to successfully colonize humans at high doses with no adverse effects, and E. coli Nissle 1917, a human commensal strain that is used in Europe as a preventative of traveler's diarrhea. We hypothesized that commensal biotypes could exert colonization resistance by consuming nutrients needed by E. coli O157:H7 to colonize, thus preventing this first step in infection. Here we report that to colonize streptomycin-treated mice E. coli HS consumes six of the twelve sugars tested and E. coli Nissle 1917 uses a complementary yet divergent set of seven sugars to colonize, thus establishing a nutritional basis for the ability of E. coli HS and Nissle 1917 to occupy distinct niches in the mouse intestine. Together these two commensals use the five sugars previously determined to be most important for colonization of E. coli EDL933, an O157:H7 strain. As predicted, the two commensals prevented E. coli EDL933 colonization. The results support a model in which invading pathogenic E. coli must compete with the gut microbiota to obtain the nutrients needed to colonize and establish infection; accordingly, the outcome of the challenge is determined by the aggregate capacity of the native microbiota to consume the nutrients required by the pathogen. PMID:23349773

  10. Nutritional Basis for Colonization Resistance by Human Commensal Escherichia coli Strains HS and Nissle 1917 against E. coli O157:H7 in the Mouse Intestine

    PubMed Central

    Maltby, Rosalie; Leatham-Jensen, Mary P.; Gibson, Terri; Cohen, Paul S.; Conway, Tyrrell

    2013-01-01

    Escherichia coli is a single species consisting of many biotypes, some of which are commensal colonizers of mammals and others that cause disease. Humans are colonized on average with five commensal biotypes, and it is widely thought that the commensals serve as a barrier to infection by pathogens. Previous studies showed that a combination of three pre-colonized commensal E. coli strains prevents colonization of E. coli O157:H7 in a mouse model (Leatham, et al., 2010, Infect Immun 77: 2876–7886). The commensal biotypes included E. coli HS, which is known to successfully colonize humans at high doses with no adverse effects, and E. coli Nissle 1917, a human commensal strain that is used in Europe as a preventative of traveler's diarrhea. We hypothesized that commensal biotypes could exert colonization resistance by consuming nutrients needed by E. coli O157:H7 to colonize, thus preventing this first step in infection. Here we report that to colonize streptomycin-treated mice E. coli HS consumes six of the twelve sugars tested and E. coli Nissle 1917 uses a complementary yet divergent set of seven sugars to colonize, thus establishing a nutritional basis for the ability of E. coli HS and Nissle 1917 to occupy distinct niches in the mouse intestine. Together these two commensals use the five sugars previously determined to be most important for colonization of E. coli EDL933, an O157:H7 strain. As predicted, the two commensals prevented E. coli EDL933 colonization. The results support a model in which invading pathogenic E. coli must compete with the gut microbiota to obtain the nutrients needed to colonize and establish infection; accordingly, the outcome of the challenge is determined by the aggregate capacity of the native microbiota to consume the nutrients required by the pathogen. PMID:23349773

  11. Vaccination of pregnant dams with intimin(O157) protects suckling piglets from Escherichia coli O157:H7 infection.

    PubMed

    Dean-Nystrom, Evelyn A; Gansheroff, Lisa J; Mills, Melody; Moon, Harley W; O'Brien, Alison D

    2002-05-01

    Cattle are important reservoirs of enterohemorrhagic Escherichia coli (EHEC) O157:H7 that cause disease in humans. Both dairy and beef cattle are asymptomatically and sporadically infected with EHEC. Our long-term goal is to develop an effective vaccine to prevent cattle from becoming infected and transmitting EHEC O157:H7 to humans. We used passive immunization of neonatal piglets (as a surrogate model) to determine if antibodies against EHEC O157 adhesin (intimin(O157)) inhibit EHEC colonization. Pregnant swine (dams) with serum anti-intimin titers of < or =100 were vaccinated twice with purified intimin(O157) or sham-vaccinated with sterile buffer. Intimin(O157)-specific antibody titers in colostrum and serum of dams were increased after parenteral vaccination with intimin(O157). Neonatal piglets were allowed to suckle vaccinated or sham-vaccinated dams for up to 8 h before they were inoculated with 10(6) CFU of a Shiga toxin-negative (for humane reasons) strain of EHEC O157:H7. Piglets were necropsied at 2 to 10 days after inoculation, and intestinal samples were collected for determination of bacteriological counts and histopathological analysis. Piglets that ingested colostrum containing intimin(O157)-specific antibodies from vaccinated dams, but not those nursing sham-vaccinated dams, were protected from EHEC O157:H7 colonization and intestinal damage. These results establish intimin(O157) as a viable candidate for an EHEC O157:H7 antitransmission vaccine. PMID:11953378

  12. Evolution of Shiga toxin-producing Escherichia coli O157: eight major lineages of human and cattle origin strain signature genotypes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cattle are a major reservoir for Shiga toxin-producing Escherichia coli O157 (STEC O157) and harbor genetic subtypes that do not all associate with human disease. STEC O157 evolved from an E. coli O55:H7 progenitor, however, depauperate nucleotide polymorphism discovery from cattle and human origin...

  13. Detection and Prevalence of Verotoxin-Producing Escherichia coli O157 and Non-O157 Serotypes in a Canadian Watershed

    PubMed Central

    Johnson, R. P.; Holtslander, B.; Mazzocco, A.; Roche, S.; Thomas, J. L.; Pollari, F.

    2014-01-01

    Verotoxin-producing Escherichia coli (VTEC) strains are the cause of food-borne and waterborne illnesses around the world. Traditionally, surveillance of the human population as well as the environment has focused on the detection of E. coli O157:H7. Recently, increasing recognition of non-O157 VTEC strains as human pathogens and the German O104:H4 food-borne outbreak have illustrated the importance of considering the broader group of VTEC organisms from a public health perspective. This study presents the results of a comparison of three methods for the detection of VTEC in surface water, highlighting the efficacy of a direct VT immunoblotting method without broth enrichment for detection and isolation of O157 and non-O157 VTEC strains. The direct immunoblot method eliminates the need for an enrichment step or the use of immunomagnetic separation. This method was developed after 4 years of detecting low frequencies (1%) of E. coli O157:H7 in surface water in a Canadian watershed, situated within one of the FoodNet Canada integrated surveillance sites. By the direct immunoblot method, VTEC prevalence estimates ranged from 11 to 35% for this watershed, and E. coli O157:H7 prevalence increased to 4% (due to improved method sensitivity). This direct testing method provides an efficient means to enhance our understanding of the prevalence and types of VTEC in the environment. This study employed a rapid evidence assessment (REA) approach to frame the watershed findings with watershed E. coli O157:H7 prevalences reported in the literature since 1990 and the knowledge gap with respect to VTEC detection in surface waters. PMID:24487525

  14. The effect of oxidative stress on gene expression of Shiga toxin-producing Escherichia coli (STEC) O157:H7 and non-O157 serotypes.

    PubMed

    Mei, Gui-Ying; Tang, Joshua; Carey, Christine; Bach, Susan; Kostrzynska, Magdalena

    2015-12-23

    Understanding the survival mechanisms used by Shiga toxin-producing Escherichia coli (STEC), including O157:H7 and non-O157 serotypes, is important for minimizing contamination of fresh produce and occurrence of foodborne outbreaks. Recent outbreaks linked to leafy green vegetables and sprouted seeds have prompted researchers to focus on investigating decontamination strategies. Several studies showed that hydrogen peroxide (H2O2) treatment has been effective in reducing pathogens on fresh produce. As such, the effect of hydrogen peroxide on stress-associated and virulence gene expression in six STEC isolates was investigated in this study. Logarithmic phase cells of E. coli O157:H7 (EDL933) and non-O157 serotypes, including E. coli O26:H11 (EC20070549), O103:H2 (EC19970811), O104:H4 (NML#11-3088), O111:NM (EC20070546) and O145:NM (EC19970355) were exposed to 2.5mM H2O2 for 40 min and gene expression was evaluated using quantitative real-time PCR. Different patterns of gene expression were observed in E. coli O157:H7 and non-O157 serotypes. Particularly, Shiga toxin gene stx2 was upregulated in O157:H7, but not in O104:H4. Moreover, stx1 was significantly upregulated in STEC O157:H7, but only slightly upregulated Stx1-positive non-O157 serotypes. However genes related to motility (fliC) and intimin gene (eae) were downregulated in most strains. Stress-associated sodA gene encoding manganese superoxide dismutase was significantly upregulated in all serotypes. The dps gene coding for non-specific DNA binding protein was upregulated in O145:NM, O111:NM, O103:H2 and O26:H11. However genes related to cold shock (cspC) and acid resistance (gadW) were significantly downregulated in all strains tested. The results of this study provide a basic understanding of the oxidative stress impact on survival and virulence of non-O157 serotype STEC strains. PMID:26318408

  15. Acid Resistance and Molecular Characterization of Escherichia coli O157:H7 and Different Non-O157 Shiga Toxin-Producing E. coli Serogroups.

    PubMed

    Kim, Gwang-Hee; Breidt, Frederick; Fratamico, Pina; Oh, Deog-Hwan

    2015-10-01

    The objective of this study was to compare the acid resistance (AR) of non-O157 Shiga toxin-producing Escherichia coli (STEC) strains belonging to serogroups O26, O45, O103, O104, O111, O121, and O145 with O157:H7 STEC isolated from various sources in 400 mM acetic acid solutions (AAS) at pH 3.2 and 30 °C for 25 min with or without glutamic acid. Furthermore, the molecular subgrouping of the STEC strains was analyzed with the repetitive sequence-based PCR (rep-PCR) method using a DiversiLab(TM) system. Results for a total of 52 strains ranged from 0.31 to 5.45 log reduction CFU/mL in the absence of glutamic acid and 0.02 to 0.33 CFU/mL in the presence of glutamic acid except for B447 (O26:H11), B452 (O45:H2), and B466 (O104:H4) strains. Strains belonging to serogroups O111, O121, and O103 showed higher AR than serotype O157:H7 strains in the absence of glutamic acid. All STEC O157:H7 strains exhibited a comparable DNA pattern with more than 95% similarity in the rep-PCR results, as did the strains belonging to serogroups O111 and O121. Surprisingly, the DNA pattern of B458 (O103:H2) was similar to that of O157:H7 strains with 82% similarity, and strain B458 strain showed the highest AR to AAS among the O103 strains with 0.44 log reduction CFU/mL without glutamic acid. In conclusion, STEC serotypes isolated from different sources exhibited diverse AR and genetic subtyping patterns. Results indicated that some non-O157 STEC strains may have higher AR than STEC O157:H7 strains under specific acidic conditions, and the addition of glutamic acid provided enhanced protection against exposure to AAS. PMID:26375176

  16. International Comparison of Clinical, Bovine, and Environmental Escherichia coli O157 Isolates on the Basis of Shiga Toxin-Encoding Bacteriophage Insertion Site Genotypes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Enterohemorrhagic Escherichia coli O157:H7 (EHEC O157) is a major cause of bloody diarrhea and hemolytic uremic syndrome (HUS) worldwide, although the annual reported incidence of EHEC O157 associated HUS in various countries ranges forty-fold (0.01 to 0.41 cases per 100,000 population). Cattle are ...

  17. Reduction of Adherence of E. coli O157:H7 to HEp-2 Cells and to Bovine Large Intestinal Mucosal Explants by Colicinogenic E. coli

    PubMed Central

    Etcheverría, A. I.; Arroyo, G. H.; Alzola, R.; Parma, A. E.

    2011-01-01

    Enterohemorrhagic E. coli strains (EHEC) had emerged as foodborne pathogens and cause in human diarrhea and hemolytic-uremic syndrome. Because of the widespread distribution of EHEC serotypes and O157 and non-O157 in cattle population, its control will require interventions at the farm level such as the administration of probiotics that produce inhibitory metabolites. E. coli O157:H7 shows tissue tropisms for the gastrointestinal tract (GIT) of cattle. The aim of this study was to test the ability of a colicinogenic E. coli (isolated from bovine) to reduce the adherence of E. coli O157:H7 to HEp-2 cells and to GIT of cattle. We inoculated HEp-2 cells and bovine colon explants with both kinds of strains. Colicinogenic E. coli was able to reduce the adherence of E. coli O157:H7 to HEp-2 cells and to bovine tissues. PMID:23724308

  18. Effects of environmental parameters on the dual-species biofilms formed by Escherichia coli O157:H7 and Ralstonia insidiosa, a strong biofilm producer isolated from a fresh-cut produce processing plant.

    PubMed

    Liu, Nancy T; Nou, Xiangwu; Bauchan, Gary R; Murphy, Charles; Lefcourt, Alan M; Shelton, Daniel R; Lo, Y Martin

    2015-01-01

    Biofilm-forming bacteria resident to food processing facilities are a food safety concern due to the potential of biofilms to harbor foodborne bacterial pathogens. When cultured together, Ralstonia insidiosa, a strong biofilm former frequently isolated from produce processing environments, has been shown to promote the incorporation of Escherichia coli O157:H7 into dual-species biofilms. In this study, interactions between E. coli O157:H7 and R. insidiosa were examined under different incubating conditions. Under static culture conditions, the incorporation of E. coli O157:H7 into biofilms with R. insidiosa was not significantly affected by either low incubating temperature (10°C) or by limited nutrient availability. Greater enhancement of E. coli O157:H7 incorporation in dual-species biofilms was observed by using a continuous culture system with limited nutrient availability. Under the continuous culture conditions used in this study, E coli O157:H7 cells showed a strong tendency of colocalizing with R. insidiosa on a glass surface at the early stage of biofilm formation. As the biofilms matured, E coli O157:H7 cells were mostly found at the bottom layer of the dual-species biofilms, suggesting an effective protection by R. insidiosa in the mature biofilms. PMID:25581186

  19. Prevalence and antimicrobial resistance of porcine O157 and non-O157 Shiga toxin-producing Escherichia coli from India.

    PubMed

    Rajkhowa, Swaraj; Sarma, Dilip Kumar

    2014-08-01

    The aims of this study were to determine the prevalence of Shiga toxin-producing Escherichia coli (STEC) strains in pigs as a possible STEC reservoir in India as well as to characterize the STEC strains and to determine the antimicrobial resistance pattern of the strains. A total of 782 E. coli isolates from clinically healthy (n = 473) and diarrhoeic piglets (309) belonging to major pig-producing states of India were screened by the polymerase chain reaction (PCR) assay for the presence of virulence genes characteristic for STEC, that is, Shiga toxin-producing gene(s) (stx1, stx2), intimin (eae), enterohemolysin (hlyA) and STEC autoagglutinating adhesin (Saa). Overall STEC were detected in 113 (14.4%) piglets, and the prevalence of E. coli O157 and non-O157 STEC were 4 (0.5%) and 109 (13.9%), respectively. None of the O157 STEC isolates carried gene encoding for H7 antigen (fliCh7). The various combinations of virulence genes present in the strains studied were stx1 in 4.6%, stx1 in combination with stx2 gene in 5.1%, stx1 in combination with stx2 and ehxA in 0.6%, stx1 in combination with stx2 and eae in 0.2% and stx2 alone in 3.7%. All STEC isolates were found negative for STEC autoagglutinating adhesin (Saa). The number of STEC isolates which showed resistance to antimicrobials such as ampicillin, tetracycline, streptomycin, lincomycin, nalidixic acid, sulfadiazine, penicillin, gentamicin, kanamycin and ceftriaxone were 100, 99, 98, 97, 95, 94, 92, 88, 85 and 85, respectively. Ninety-seven isolates showed resistance to more than 2 antimicrobials, and 8 resistance groups (R1 to R8) were observed. This study demonstrates that pigs in India harbour both O157 and non-O157 STEC, and this may pose serious public health problems in future. PMID:24743858

  20. Shiga toxin-producing Escherichia coli O157:H7 in milk and milk products in Ogun State, Nigeria.

    PubMed

    Ivbade, Akhigbe; Ojo, Olufemi Ernest; Dipeolu, Morenike Atinuke

    2014-01-01

    Shiga toxin producing Escherichia coli (STEC) O157 is a major cause of food-borne illnesses in humans. This study investigated the presence of STEC O157 in milk and milk products in Ogun State, Nigeria. Of a total of 202 samples 10 (5%) were positive for STEC O157 including 1 (2%) of 50 raw milk samples, 3 (6%) of 50 samples of fresh local cheese, 1 (2%) of 50 samples of fried local cheese and 5 (9.6%) of 52 fermented milk samples. There was no significant difference (p>0.05) in the prevalence of STEC O157 among the sample types. Of 10 isolates, shiga toxin 1 gene (stx1) was detected only in 2 samples (20%), shiga toxin 2 (stx2) was extracted only in 6 samples (60%), stx1 /stx2 in 2 samples (20.0%), intimin gene (eaeA) in 5 samples (50%), and enterohaemolysin (E-hlyA) gene was isolated in 7 (70%) samples. Rates of resistance of the STEC O157 isolates were: amoxicillin/clavulanic acid 100%, ampicillin 100%, chloramphenicol 60%, nalidixic acid 20%, norfloxacin 10%, streptomycin 30%, sulphamethoxazole/trimethprim 20%, and tetracycline 90%. The isolates were all susceptible to ciprofloxacin and neomycin. The presence of virulent multidrug resistant E. coli O157 strains in milk and milk products as revealed by this study unveils a risk of human exposure to these potentially fatal pathogens following consumption of contaminated products. PMID:25273960

  1. Antibody responses elicited in mice immunized with Bacillus subtilis vaccine strains expressing Stx2B subunit of enterohaemorragic Escherichia coli O157:H7.

    PubMed

    Gomes, P A D P; Bentancor, L V; Paccez, J D; Sbrogio-Almeida, M E; Palermo, M S; Ferreira, R C C; Ferreira, L C S

    2009-04-01

    No effective vaccine or immunotherapy is presently available for patients with the hemolytic uremic syndrome (HUS) induced by Shiga-like toxin (Stx) produced by enterohaemorragic Escherichia coli (EHEC) strains, such as those belonging to the O157:H7 serotype. In this work we evaluated the performance of Bacillus subtilis strains, a harmless spore former gram-positive bacterium species, as a vaccine vehicle for the expression of Stx2B subunit (Stx2B). A recombinant B. subtilis vaccine strain expressing Stx2B under the control of a stress inducible promoter was delivered to BALB/c mice via oral, nasal or subcutaneous routes using both vegetative cells and spores. Mice immunized with vegetative cells by the oral route developed low but specific anti-Stx2B serum IgG and fecal IgA responses while mice immunized with recombinant spores developed anti-Stx2B responses only after administration via the parenteral route. Nonetheless, serum anti-Stx2B antibodies raised in mice immunized with the recombinant B. subtilis strain did not inhibit the toxic effects of the native toxin, both under in vitro and in vivo conditions, suggesting that either the quantity or the quality of the induced immune response did not support an effective neutralization of Stx2 produced by EHEC strains. PMID:24031368

  2. Antibody responses elicited in mice immunized with Bacillus subtilis vaccine strains expressing Stx2B subunit of enterohaemorragic Escherichia coli O157:H7

    PubMed Central

    Gomes, P.A.D.P.; Bentancor, L.V.; Paccez, J.D.; Sbrogio-Almeida, M.E.; Palermo, M.S.; Ferreira, R.C.C.; Ferreira, L.C.S.

    2009-01-01

    No effective vaccine or immunotherapy is presently available for patients with the hemolytic uremic syndrome (HUS) induced by Shiga-like toxin (Stx) produced by enterohaemorragic Escherichia coli (EHEC) strains, such as those belonging to the O157:H7 serotype. In this work we evaluated the performance of Bacillus subtilis strains, a harmless spore former gram-positive bacterium species, as a vaccine vehicle for the expression of Stx2B subunit (Stx2B). A recombinant B. subtilis vaccine strain expressing Stx2B under the control of a stress inducible promoter was delivered to BALB/c mice via oral, nasal or subcutaneous routes using both vegetative cells and spores. Mice immunized with vegetative cells by the oral route developed low but specific anti-Stx2B serum IgG and fecal IgA responses while mice immunized with recombinant spores developed anti-Stx2B responses only after administration via the parenteral route. Nonetheless, serum anti-Stx2B antibodies raised in mice immunized with the recombinant B. subtilis strain did not inhibit the toxic effects of the native toxin, both under in vitro and in vivo conditions, suggesting that either the quantity or the quality of the induced immune response did not support an effective neutralization of Stx2 produced by EHEC strains. PMID:24031368

  3. RcsB contributes to the distinct stress fitness between Escherichia coli O157:H7 curli variants of 1993 hamburger-associated outbreak strains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Curli are adhesive fimbriae of Enterobactericaeae and are involved in surface attachment, cell aggregation and biofilm formation. We previously reported that natural curli variants of E. coli O157:H7 (EcO157) displayed distinct acid resistance; however, this difference was not linked to the curli fi...

  4. Pathogenesis of Escherichia coli O157:H7 strain 86-24 following oral infection of BALB/c mice with an intact commensal flora.

    PubMed

    Mohawk, Krystle L; Melton-Celsa, Angela R; Zangari, Tonia; Carroll, Erica E; O'Brien, Alison D

    2010-01-01

    Escherichia coli O157:H7 is a food-borne pathogen that can cause hemorrhagic colitis and, occasionally, hemolytic uremic syndrome, a sequela of infection that can result in renal failure and death. Here we sought to model the pathogenesis of orally-administered E. coli O157:H7 in BALB/c mice with an intact intestinal flora. First, we defined the optimal dose that permitted sustained fecal shedding of E. coli O157:H7 over 7 days ( approximately 10(9) colony forming units). Next, we monitored the load of E. coli O157:H7 in intestinal sections over time and observed that the cecum was consistently the tissue with the highest E. coli O157:H7 recovery. We then followed the expression of two key E. coli O157:H7 virulence factors, the adhesin intimin and Shiga toxin type 2, and detected both proteins early in infection when bacterial burdens were highest. Additionally, we noted that during infection, animals lost weight and approximately 30% died. Moribund animals also exhibited elevated levels of blood urea nitrogen, and, on necropsy, showed evidence of renal tubular damage. We conclude that conventional mice inoculated orally with high doses of E. coli O157:H7 can be used to model both intestinal colonization and subsequent development of certain extraintestinal manifestations of E. coli O157:H7 disease. PMID:20096770

  5. Pathogenesis of Escherichia coli O157:H7 strain 86-24 following oral infection of BALB/c mice with an intact commensal flora

    PubMed Central

    Mohawk, Krystle L.; Melton-Celsa, Angela R.; Zangari, Tonia; Carroll, Erica E.; O’Brien, Alison D.

    2010-01-01

    Escherichia coli O157:H7 is a food-borne pathogen that can cause hemorrhagic colitis and, occasionally, hemolytic uremic syndrome, a sequela of infection that can result in renal failure and death. Here we sought to model the pathogenesis of orally-administered E. coli O157:H7 in BALB/c mice with an intact intestinal flora. First, we defined the optimal dose that permitted sustained fecal shedding of E. coli O157:H7 over 7 days (~109 colony-forming units). Next, we monitored the load of E. coli O157:H7 in intestinal sections over time and observed that the cecum was consistently the tissue with the highest E. coli O157:H7 recovery. We then followed the expression of two key E. coli O157:H7 virulence factors, the adhesin intimin and Shiga toxin type 2, and detected both proteins early in infection when bacterial burdens were highest. Additionally, we noted that during infection, animals lost weight and ~30% died. Moribund animals also exhibited elevated levels of blood urea nitrogen, and, on necropsy, showed evidence of renal tubular damage. We conclude that conventional mice inoculated orally with high doses of E. coli O157:H7 can be used to model both intestinal colonization and subsequent development of certain extraintestinal manifestations of E. coli O157:H7 disease. PMID:20096770

  6. Purification and characterization of lipopolysaccharides from six strains of non-O157 Shiga toxin-producing Escherichia coli.

    PubMed

    Stromberg, Loreen R; Stromberg, Zachary R; Banisadr, Afsheen; Graves, Steven W; Moxley, Rodney A; Mukundan, Harshini

    2015-09-01

    Certain Shiga toxin-producing Escherichia coli (STEC) are virulent human pathogens that are most often acquired through contaminated food. The United States Department of Agriculture, Food Safety and Inspection Service has declared several serogroups of STEC as adulterants in non-intact raw beef products. Hence, sensitive and specific tests for the detection of these STEC are a necessity for implementation in food safety programs. E. coli serogroups are identified by their respective O-antigen moiety on the lipopolysaccharide (LPS) macromolecule. We propose that the development of O-antigen-specific immunological assays can facilitate simple and rapid discriminatory detection of STEC in beef. However, the resources (antigens and antibodies) required for such development are not readily available. To overcome this, we extracted and characterized LPS and O-antigen from six STEC strains. Using hot phenol extraction, we isolated the LPS component from each strain and purified it using a series of steps to eliminate proteins, nucleic acids, and lipid A antigens. Antigens and crude LPS extracts were characterized using gel electrophoresis, immunoblotting, and modified Western blotting with commercially available antibodies, thus assessing the serogroup specificity and sensitivity of available ligands as well. The results indicate that, while many commercially available antibodies bind LPS, their activities and specificities are highly variable, and often not as specific as those required for serogroup discrimination. This variability could be minimized by the production of antibodies specific for the O-antigen. Additionally, the antigens generated from this study provide a source of characterized LPS and O-antigen standards for six serogroups of STEC. PMID:26093258

  7. Isolation and characterization of shiga toxin-producing Escherichia coli serogroups O26, O45, O103, O111, O113, O121, O145, and O157 shed from range and feedlot cattle from postweaning to slaughter

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cattle are the main reservoirs for Shiga toxin-producing Escherichia coli (STEC) strains. E. coli O26, O45, O103, O111, O121, O145, and O157 are among the STEC serogroups that cause severe foodborne illness and have been declared as adulterants by the United States Department of Agriculture, Food Sa...

  8. Prevalence of Escherichia coli O157:H7 in Children with Bloody Diarrhea Referring to Abuzar Teaching Hospital, Ahvaz, Iran

    PubMed Central

    Khosravi, Azar Dokht; Sheikh, Ahmad Farajzadeh; Ahmadzadeh, Ali; Shamsizadeh, Ahmad

    2016-01-01

    Introduction Escherichia coli O157: H7 are recognized as important aetiological agents of diarrhea in children, particularly in developed countries. Aim The aim of the study was to determine the rates of detection of E. coli O157: H7strains among children in Ahvaz, Iran. Materials and Methods From June 2010 to December 2010, 137 diarrheal stool samples of children were collected. E.coli was identified by standard microbiological techniques. O157 or O157:H7 subtypes discerned by serological tests. Results Of the 137 E. coli isolates, enteropathogens were found in 53 (38.7%) of the patients as follow: Shigella spp. (75.5%), EPEC (enteropathogenic E. coli) (16.9%), Campylobacter spp. (3.8%) and Salmonella spp. (3.8%). None of the isolated E. coli was O157:H7 serotype. Conclusion This shows that non-O157:H7 E. coli are the major cause of paediatric infections in this region of Iran. PMID:26894066

  9. Inoculation of beef with low concentrations of Escherichia coli O157:H7 and examination of factors that interfere with its detection by culture isolation and rapid methods

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Reliable detection of Escherichia coli O157:H7 in test-and-hold programs requires the detection of as little as 1 CFU E. coli O157:H7 in a sample of beef trim or ground beef that is up to 375 grams in size. We present a reliable protocol for generating a control inoculum for verification testing at...

  10. Leakage of intracellular UV materials of high hydrostatic pressure-injured Escherichia coli O157:H7 strains in tomato juice.

    PubMed

    Ukuku, D O; Zhang, H; Bari, M L; Yamamoto, K; Kawamoto, S

    2009-11-01

    The behavior of high hydrostatic pressure-injured Escherichia coli O157:H7 cells (strain SEA13B88 and a strain from the June-July 1999 Oklahoma juice outbreak) in tomato juice (pH 4.1) and phosphate-buffered saline (PBS; pH 7.2) at final concentrations of 8.4 to 8.8 log CFU/ml, respectively, and treated at 400, 500, and 600 MPa for 40 min at 25 and 35 degrees C with storage at 5 and 23 degrees C for 1,800 min was investigated. Immediately after treatment and every 3 h for 24 h of storage, an aliquot (0.1 ml) was plated on Trypticase soy agar and sorbitol MacConkey agar to determine the percentage of injured population. Leakage of UV materials and possible recovery from injury were investigated. Pressure (600-MPa) treatment at 35 degrees C for 40 min caused a higher percentage of bacterial injury than for 10 min of treatment. A higher percentage of injured population was found among the Oklahoma strain cells than among strain SEA13B88 cells, and differences in viability loss for bacterial strains were determined. The viability loss determined in PBS was 4.8 log for SEA13B88 cells and 5.2 log for Oklahoma cells, while losses of 5.4 and 5.7 log were determined in tomato juice for SEA13B88 and Oklahoma cells, respectively. The leakage of intracellular materials of injured Oklahoma cells was higher than that observed for SEA13B88 cells, but injured Oklahoma cells recovered faster in PBS. However, injured and healthy populations for both strains were below detection in tomato juice stored at 5 degrees C for 1,440 min. PMID:19903409

  11. Determination of Antimicrobial Activity of Sorrel (Hibiscus sabdariffa) on Esherichia coli O157:H7 Isolated from Food, Veterinary, and Clinical Samples

    PubMed Central

    Fullerton, Marjorie; Khatiwada, Janak; Johnson, Jacqueline U.; Davis, Shurrita

    2011-01-01

    Abstract The use of medicinal plants as natural antimicrobial agents is gaining popularity. Sorrel (Hibiscus sabdariffa) is widely used for the treatment of diseases. The objective of this study was to investigate the antimicrobial activity of sorrel on Escherichia coli O157:H7 isolates from food, veterinary, and clinical samples. Phenolics of the calyces were extracted from 10 g of ground, freeze-dried samples using 100 mL of 80% aqueous methanol. Concentrations of 10%, 5%, and 2.5% methanol extract of sorrel were investigated for its antimicrobial activity. Inhibition zones were indicated by a lack of microbial growth due to inhibitory concentrations of sorrel diffused into semisolid culture medium beneath the sorrel-impregnated disk. The results of this experiment showed that the most potent sorrel concentration was 10%, then 5%, and finally 2.5%. The overall mean zone of inhibition for the sorrel extract was 12.66 mm for 10%, 10.75 mm for 5%, and 8.9 mm for 2.5%. The highest inhibition zones (11.16 mm) were observed in veterinary samples, and the lowest (10.57 mm) in the food samples. There were significant (P<.05) differences among mean zones of inhibition found in the food, veterinary, and clinical sources. Based on the source of samples and concentration of sorrel extract, the lowest mean inhibition was 7.00±0.04 mm from clinical samples, and the highest was 15.37±0.61 mm from a food source. These findings indicated that sorrel was effective at all levels in inhibiting E. coli O157:H7; thus it possesses antimicrobial activity and hold great promise as an antimicrobial agent. PMID:21548802

  12. Repression of the locus of the enterocyte effacement-encoded regulator of gene transcription of Escherichia coli O157:H7 by Lactobacillus reuteri culture supernatants is LuxS and strain dependent.

    PubMed

    Jelcić, Ivan; Hüfner, Eric; Schmidt, Herbert; Hertel, Christian

    2008-05-01

    Culture supernatants of Lactobacillus reuteri ATCC 55730 repressed ler expression in Escherichia coli O157:H7 cells, but neither the strain's isogenic luxS mutant nor the L. reuteri 100-23C wild-type strain and its luxS mutant elicited a comparable effect. Furthermore, the epinephrine-mediated induction of ler expression was repressed by secreted substance(s) of L. reuteri ATCC 55730. PMID:18378666

  13. Effective medicinal plants against enterohaemorrhagic Escherichia coli O157:H7.

    PubMed

    Voravuthikunchai, Supayang; Lortheeranuwat, Amornrat; Jeeju, Wanpen; Sririrak, Trechada; Phongpaichit, Souwalak; Supawita, Thanomjit

    2004-09-01

    The stimulating effect of subinhibitory concentrations of antibiotics on the production of verocytotoxin (VT) by enterohaemorrhagic Escherichia coli (EHEC) O157:H7 has been claimed. The purpose of this study was to find an alternative, but bioactive medicine for the treatment of this organism. Fifty-eight preparations of aqueous and ethanolic extracts of 38 medicinal plant species commonly used in Thailand to cure gastrointestinal infections were tested for their antibacterial activity against different strains of Escherichia coli, including 6 strains of Escherichia coli O157:H7, Escherichia coli O26:H11, Escherichia coli O111:NM, Escherichia coli O22; 5 strains of Escherichia coli isolated from bovine; and Escherichia coli ATCC 25922. Inhibition of growth was primarily tested by the paper disc agar diffusion method. Among the medicinal plants tested, only 8 species (21.05%) exhibited antimicrobial activity against Escherichia coli O157:H7. Acacia catechu, Holarrhena antidysenterica, Peltophorum pterocarpum, Psidium guajava, Punica granatum, Quercus infectoria, Uncaria gambir, and Walsura robusta demonstrated antibacterial activity with inhibition zones ranging from 7 to 17 mm. The greatest inhibition zone against Escherichia coli O157:H7 (RIMD 05091083) was produced from the ethanolic extract of Quercus infectoria. Minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) were determined by the agar microdilution method and agar dilution method in petri dishes with millipore filter. Both aqueous and ethanolic extracts of Quercus infectoria and aqueous extract of Punica granatum were highly effective against Escherichia coli O157:H7 with the best MIC and MBC values of 0.09, 0.78, and 0.19, 0.39 mg/ml, respectively. These plant species may provide alternative but bioactive medicines for the treatment of Escherichia coli O157:H7 infection. PMID:15261962

  14. Genotypic characterization of non-O157 Shiga toxin-producing Escherichia coli in beef abattoirs of Argentina.

    PubMed

    Masana, M O; D'Astek, B A; Palladino, P M; Galli, L; Del Castillo, L L; Carbonari, C; Leotta, G A; Vilacoba, E; Irino, K; Rivas, M

    2011-12-01

    The non-O157 Shiga toxin-producing Escherichia coli (STEC) contamination in carcasses and feces of 811 bovines in nine beef abattoirs from Argentina was analyzed during a period of 17 months. The feces of 181 (22.3%) bovines were positive for non-O157 STEC, while 73 (9.0%) of the carcasses showed non-O157 STEC contamination. Non-O157 STEC strains isolated from feces (227) and carcasses (80) were characterized. The main serotypes identified were O178:H19, O8:H19, O130:H11, and O113:H21, all of which have produced sporadic cases of hemolytic-uremic syndrome in Argentina and worldwide. Twenty-two (7.2%) strains carried a fully virulent stx/eae/ehxA genotype. Among them, strains of serotypes O103:[H2], O145:NM, and O111:NM represented 4.8% of the isolates. Xba I pulsed-field gel electrophoresis pattern analysis showed 234 different patterns, with 76 strains grouped in 30 clusters. Nine of the clusters grouped strains isolated from feces and from carcasses of the same or different bovines in a lot, while three clusters were comprised of strains distributed in more than one abattoir. Patterns AREXSX01.0157, AREXBX01.0015, and AREXPX01.0013 were identified as 100% compatible with the patterns of one strain isolated from a hemolytic-uremic syndrome case and two strains previously isolated from beef medallions, included in the Argentine PulseNet Database. In this survey, 4.8% (39 of 811) of the bovine carcasses appeared to be contaminated with nonO157 STEC strains potentially capable of producing sporadic human disease, and a lower proportion (0.25%) with strains able to produce outbreaks of severe disease. PMID:22186039

  15. Identification of protozoa in dairy lagon Wwsterwater that consume Escherichia coli O157:H7 preferentially

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Escherichia coli O157:H7 (EcO157), an agent of life threatening hemolytic-uremic syndrome, resides in ruminants and released in feces at numbers as high as 10 million cells per gram. EcO157 could survive in manure for as long as 21 months, but we observed a rapid disappearance of an outbreak strain ...

  16. Topological data analysis of Escherichia coli O157:H7 and non-O157 survival in soils

    PubMed Central

    Ibekwe, Abasiofiok M.; Ma, Jincai; Crowley, David E.; Yang, Ching-Hong; Johnson, Alexis M.; Petrossian, Tanya C.; Lum, Pek Y.

    2014-01-01

    Shiga toxin-producing E. coli O157:H7 and non-O157 have been implicated in many foodborne illnesses caused by the consumption of contaminated fresh produce. However, data on their persistence in soils are limited due to the complexity in datasets generated from different environmental variables and bacterial taxa. There is a continuing need to distinguish the various environmental variables and different bacterial groups to understand the relationships among these factors and the pathogen survival. Using an approach called Topological Data Analysis (TDA); we reconstructed the relationship structure of E. coli O157 and non-O157 survival in 32 soils (16 organic and 16 conventionally managed soils) from California (CA) and Arizona (AZ) with a multi-resolution output. In our study, we took a community approach based on total soil microbiome to study community level survival and examining the network of the community as a whole and the relationship between its topology and biological processes. TDA produces a geometric representation of complex data sets. Network analysis showed that Shiga toxin negative strain E. coli O157:H7 4554 survived significantly longer in comparison to E. coli O157:H7 EDL 933, while the survival time of E. coli O157:NM was comparable to that of E. coli O157:H7 EDL 933 in all of the tested soils. Two non-O157 strains, E. coli O26:H11 and E. coli O103:H2 survived much longer than E. coli O91:H21 and the three strains of E. coli O157. We show that there are complex interactions between E. coli strain survival, microbial community structures, and soil parameters. PMID:25250242

  17. Spinach-associated Escherichia coli O157:H7 Outbreak, Utah and New Mexico, 2006

    PubMed Central

    Wendelboe, Aaron M.; Wendel, Arthur; Jepson, Barbara; Torres, Paul; Smelser, Chad; Rolfs, Robert T.

    2008-01-01

    In 2006, Utah and New Mexico health departments investigated a multistate cluster of Escherichia coli O157:H7. A case–control study of 22 case-patients found that consuming bagged spinach was significantly associated with illness (p<0.01). The outbreak strain was isolated from 3 bags of 1 brand of spinach. Nationally, 205 persons were ill with the outbreak strain. PMID:18826833

  18. Transcriptomic Analysis of Escherichia coli O157:H7 and K-12 Cultures Exposed to Inorganic and Organic Acids in Stationary Phase Reveals Acidulant- and Strain-Specific Acid Tolerance Responses ▿ †

    PubMed Central

    King, Thea; Lucchini, Sacha; Hinton, Jay C. D.; Gobius, Kari

    2010-01-01

    The food-borne pathogen Escherichia coli O157:H7 is commonly exposed to organic acid in processed and preserved foods, allowing adaptation and the development of tolerance to pH levels otherwise lethal. Since little is known about the molecular basis of adaptation of E. coli to organic acids, we studied K-12 MG1655 and O157:H7 Sakai during exposure to acetic, lactic, and hydrochloric acid at pH 5.5. This is the first analysis of the pH-dependent transcriptomic response of stationary-phase E. coli. Thirty-four genes and three intergenic regions were upregulated by both strains during exposure to all acids. This universal acid response included genes involved in oxidative, envelope, and cold stress resistance and iron and manganese uptake, as well as 10 genes of unknown function. Acidulant- and strain-specific responses were also revealed. The acidulant-specific response reflects differences in the modes of microbial inactivation, even between weak organic acids. The two strains exhibited similar responses to lactic and hydrochloric acid, while the response to acetic acid was distinct. Acidulant-dependent differences between the strains involved induction of genes involved in the heat shock response, osmoregulation, inorganic ion and nucleotide transport and metabolism, translation, and energy production. E. coli O157:H7-specific acid-inducible genes were identified, suggesting that the enterohemorrhagic E. coli strain possesses additional molecular mechanisms contributing to acid resistance that are absent in K-12. While E. coli K-12 was most resistant to lactic and hydrochloric acid, O157:H7 may have a greater ability to survive in more complex acidic environments, such as those encountered in the host and during food processing. PMID:20709847

  19. Escherichia coli O26 in feedlot cattle: fecal prevalence, isolation, characterization, and effects of an E. coli O157 vaccine and a direct-fed microbial.

    PubMed

    Paddock, Zac D; Renter, David G; Cull, Charley A; Shi, Xiarong; Bai, Jianfa; Nagaraja, Tiruvoor G

    2014-03-01

    Escherichia coli O26 is second only to O157 in causing foodborne, Shiga toxin-producing E. coli (STEC) infections. Our objectives were to determine fecal prevalence and characteristics of E. coli O26 in commercial feedlot cattle (17,148) that were enrolled in a study to evaluate an E. coli O157:H7 siderophore receptor and porin (SRP(®)) vaccine (VAC) and a direct-fed microbial (DFM; 10(6) colony-forming units [CFU]/animal/day of Lactobacillus acidophilus and 10(9) CFU/animal/day of Propionibacterium freudenreichii). Cattle were randomly allocated to 40 pens within 10 complete blocks; pens were randomly assigned to control, VAC, DFM, or VAC+DFM treatments. Vaccine was administered on days 0 and 21, and DFM was fed throughout the study. Pen-floor fecal samples (30/pen) were collected weekly for the last 4 study weeks. Samples were enriched in E. coli broth and subjected to a multiplex polymerase chain reaction (PCR) designed to detect O26-specific wzx gene and four major virulence genes (stx1, stx2, eae, and ehxA) and to a culture-based procedure that involved immunomagnetic separation and plating on MacConkey agar. Ten presumptive E. coli colonies were randomly picked, pooled, and tested by the multiplex PCR. Pooled colonies positive for O26 serogroup were streaked on sorbose MacConkey agar, and 10 randomly picked colonies per sample were tested individually by the multiplex PCR. The overall prevalence of E. coli O26 was higher (p<0.001) by the culture-based method compared to the PCR assay (22.7 versus 10.5%). The interventions (VAC and or DFM) had no impact on fecal shedding of O26. Serogroup O26 was recovered in pure culture from 23.9% (260 of 1089) of O26 PCR-positive pooled colonies. Only 7 of the 260 isolates were positive for the stx gene and 90.1% of the isolates possessed an eaeβ gene that codes for intimin subtype β, but not the bfpA gene, which codes for bundle-forming pilus. Therefore, the majority of the O26 recovered from feedlot cattle feces was

  20. Molecular characterization of Escherichia coli O157:H7 recovered from meat and meat products relevant to human health in Riyadh, Saudi Arabia.

    PubMed

    Hessain, Ashgan M; Al-Arfaj, Abdullah A; Zakri, Adel M; El-Jakee, Jakeen K; Al-Zogibi, Onizan G; Hemeg, Hassan A; Ibrahim, Ihab M

    2015-11-01

    Raw meat can harbor pathogenic bacteria, potentially harmful to humans such as Escherichia coli O157:H7 causing diarrhea and hemolytic-uremic syndrome (HS). Therefore, the current study was carried out to evaluate the prevalence and the molecular detection characterization of E. coli serotype O157:H7 recovered from raw meat and meat products collected from Saudi Arabia. During the period of 25th January 2013 to 25th March 2014, 370 meat samples were collected from abattoirs and markets located in Riyadh, Saudi Arabia "200 raw meat samples and 170 meat products". Bacteriological analysis of the meat samples and serotyping of the isolated E. coli revealed the isolation of 11 (2.97%) strains of E. coli O157:H7. Isolation of E. coli O157:H7 in raw beef, chicken and mutton were 2%, 2.5%, and 2.5%, respectively, however, there was no occurrence in raw turkey. The incidences of E. coli O157:H7 in ground beef, beef burgers, beef sausage, ground chicken and chicken burgers were 5%, 10%, 0.0%, 5% and 0.0%, respectively. The multiplex PCR assay revealed that 3 (27.27%) out of 11 E. coli O157:H7 isolates from raw beef, chicken and mutton had stx1, stx2, and eae while 5 (45.45%) E. coli O157:H7 isolates from ground beef, ground chicken, and raw beef had both stx1 and stx2. However, from beef burgers, only one E. coli O157:H7 isolate had stx1 while two were positive for hlyA gene. These results call for urgent attention toward appropriate controls and good hygienic practices in dealing with raw meat. PMID:26587000

  1. Molecular characterization of Escherichia coli O157:H7 recovered from meat and meat products relevant to human health in Riyadh, Saudi Arabia

    PubMed Central

    Hessain, Ashgan M.; Al-Arfaj, Abdullah A.; Zakri, Adel M.; El-Jakee, Jakeen K.; Al-Zogibi, Onizan G.; Hemeg, Hassan A.; Ibrahim, Ihab M.

    2015-01-01

    Raw meat can harbor pathogenic bacteria, potentially harmful to humans such as Escherichia coli O157:H7 causing diarrhea and hemolytic-uremic syndrome (HS). Therefore, the current study was carried out to evaluate the prevalence and the molecular detection characterization of E. coli serotype O157:H7 recovered from raw meat and meat products collected from Saudi Arabia. During the period of 25th January 2013 to 25th March 2014, 370 meat samples were collected from abattoirs and markets located in Riyadh, Saudi Arabia “200 raw meat samples and 170 meat products”. Bacteriological analysis of the meat samples and serotyping of the isolated E. coli revealed the isolation of 11 (2.97%) strains of E. coli O157:H7. Isolation of E. coli O157:H7 in raw beef, chicken and mutton were 2%, 2.5%, and 2.5%, respectively, however, there was no occurrence in raw turkey. The incidences of E. coli O157:H7 in ground beef, beef burgers, beef sausage, ground chicken and chicken burgers were 5%, 10%, 0.0%, 5% and 0.0%, respectively. The multiplex PCR assay revealed that 3 (27.27%) out of 11 E. coli O157:H7 isolates from raw beef, chicken and mutton had stx1, stx2, and eae while 5 (45.45%) E. coli O157:H7 isolates from ground beef, ground chicken, and raw beef had both stx1 and stx2. However, from beef burgers, only one E. coli O157:H7 isolate had stx1 while two were positive for hlyA gene. These results call for urgent attention toward appropriate controls and good hygienic practices in dealing with raw meat. PMID:26587000

  2. Verocytotoxin-producing Escherichia coli (VTEC) O157 and other VTEC from human infections in England and Wales: 1995-1998.

    PubMed

    Willshaw, G A; Cheasty, T; Smith, H R; O'Brien, S J; Adak, G K

    2001-02-01

    A total of 3429 isolations of verocytotoxin-producing Escherichia coli O157 (VTEC O157) was confirmed from human sources in England and Wales during the period 1995-1998. The largest annual total was 1087 in 1997. Most infections occurred in the third quarter of each year. The overall rate of infection ranged from 1.28 to 2.10/100,000 population and showed regional variation. The highest incidence was in children aged 1-4 years. Annually, between 5% and 11% of strains were from patients who had travelled abroad. There were 67 general outbreaks of infection represented by 407 (11.9%) VTEC O157 isolates. Outbreaks involved transmission by contaminated food or water, person-to-person spread and direct or indirect animal contact, and five were associated with foreign travel. The majority (76%) of strains carried verocytotoxin (VT) 2 genes and 23.3% were VT1+VT2. Most strains had the flagellar antigen H7, but c. 14% were non-motile. Approximately 20% of isolates were resistant to antimicrobial agents, predominantly streptomycin, sulphonamides and tetracycline. In addition to VTEC O157, strains of serogroup O157 that did not possess VT genes were identified. These were either derivatives of VTEC O157 that had lost VT genes or were strains with H antigens other than H7 that have never been associated with VT production. Strains of VTEC other than O157 were characterised. Most were associated with diarrhoea, bloody diarrhoea or haemolytic uraemic syndrome and had virulence markers in addition to VT. PMID:11211220

  3. Early Attachment Sites for Shiga-toxigenic Escherichia coli O157:H7 in Experimentally Inoculated Weaned Calves

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weaned 3-to- 4-month-old calves were fasted 48 h, inoculated with 10**10 CFU of Shiga toxin-positive Escherichia coli (STEC) O157:H7 strain 86-24 (STEC O157) or STEC O91:H21 strain B2F1 (STEC O91), Shiga toxin-negative E. coli O157:H7 strain 87-23 (Stx**- O157), or non-pathogenic control E. coli, ne...

  4. [Isolation, characterization and typing of Escherichia coil 0157:H7 strains from beef products and milk].

    PubMed

    Roldán, M L; Chinen, I; Otero, J L; Miliwebsky, E S; Alfaro, N; Burns, P; Rivas, M

    2007-01-01

    Shiga toxin (Stx)-producing Escherichia coli (STEC) is an emergent pathogen associated with foodborne diseases, especially foodstuffs of animal origin. A total of 250 beef samples (ground beef and hamburgers) obtained from retail outlets in Santa Fe and Santo Tomé cities, and 150 milk samples from bulk tank milk from dairy barns of the region were analyzed by selective enrichment and immunomagnetic separation. Escherichia coli O157:H7 stx2, eae and ehxA positive strains were isolated from three (1.2%) beef samples. The strains could be differentiated by pulsed-field gel electrophoresis, phagetyping and genotyping of stx. The milk samples were negative for STEC O157. These findings confirm the role of food of animal origin in the epidemiology of E. coli O157:H7 - associated diseases. PMID:17702260

  5. Epidemiology and microbiology of Shiga toxin-producing Escherichia coli other than serogroup O157 in England, 2009-2013.

    PubMed

    Byrne, Lisa; Vanstone, Gemma L; Perry, Neil T; Launders, Naomi; Adak, Goutam K; Godbole, Gauri; Grant, Kathie A; Smith, Robin; Jenkins, Claire

    2014-09-01

    The implementation of direct testing of clinical faecal specimens for gastrointestinal (GI) pathogens by PCR offers a sensitive and comprehensive approach for the detection of Shiga toxin-producing Escherichia coli (STEC). The introduction of a commercial PCR assay, known as GI PCR, for the detection of GI pathogens at three frontline hospital laboratories in England between December 2012 and December 2013 led to a significant increase in detection of STEC other than serogroup O157 (non-O157 STEC). In 2013, 47 isolates were detected in England, compared with 57 in the preceding 4 years (2009-2012). The most common non-O157 STEC serogroup detected was O26 (23.2 %). A total of 47 (47.5 %) STEC isolates had stx2 only, 28 (28.3 %) carried stx1 and stx2, and the remaining 24 (24.2 %) had stx1 only. Stx2a (64.0 %) was the most frequently detected Stx2 subtype. The eae (intimin) gene was detected in 52 (52.5 %) non-O157 STEC isolates. Six strains of STEC O104 had aggR, but this gene was not detected in any other STEC serogroups in this study. Haemolytic ureamic syndrome was significantly associated with STEC strains possessing eae [odds ratio (OR) 5.845, P = 0.0235] and/or stx2a (OR 9.56, P = 0.0034) subtypes. A matched case-control analysis indicated an association between non-O157 STEC cases and contact with farm animals. Widespread implementation of the PCR approach in England will determine the true incidence of non-O157 STEC infection, highlight the burden in terms of morbidity and mortality, and facilitate the examination of risk factors to indicate whether there are niche risk exposures for particular strains. PMID:24928216

  6. Early attachment sites for Shiga-toxigenic Escherichia coli O157:H7 in experimentally inoculated weaned calves.

    PubMed

    Dean-Nystrom, Evelyn A; Stoffregen, William C; Bosworth, Brad T; Moon, Harley W; Pohlenz, Joachim F

    2008-10-01

    Weaned 3- to 4-month-old calves were fasted for 48 h, inoculated with 10(10) CFU of Shiga toxin-positive Escherichia coli (STEC) O157:H7 strain 86-24 (STEC O157) or STEC O91:H21 strain B2F1 (STEC O91), Shiga toxin-negative E. coli O157:H7 strain 87-23 (Stx(-) O157), or a nonpathogenic control E. coli strain, necropsied 4 days postinoculation, and examined bacteriologically and histologically. Some calves were treated with dexamethasone (DEX) for 5 days (3 days before, on the day of, and 1 day after inoculation). STEC O157 bacteria were recovered from feces, intestines, or gall bladders of 74% (40/55) of calves 4 days after they were inoculated with STEC O157. Colon and cecum were sites from which inoculum-type bacteria were most often recovered. Histologic lesions of attaching-and-effacing (A/E) O157(+) bacteria were observed in 69% (38/55) of the STEC O157-inoculated calves. Rectum, ileocecal valve, and distal colon were sites most likely to contain A/E O157(+) bacteria. Fecal and intestinal levels of STEC O157 bacteria were significantly higher and A/E O157(+) bacteria were more common in DEX-treated calves than in nontreated calves inoculated with STEC O157. Fecal STEC O157 levels were significantly higher than Stx(-) O157, STEC O91, or control E. coli; only STEC O157 cells were recovered from tissues. Identifying the rectum, ileocecal valve, and distal colon as early STEC O157 colonization sites and finding that DEX treatment enhances the susceptibility of weaned calves to STEC O157 colonization will facilitate the identification and evaluation of interventions aimed at reducing STEC O157 infection in cattle. PMID:18723644

  7. Altered Protozoan and Bacterial Communities and Survival of Escherichia coli O157:H7 in Monensin-Treated Wastewater from a Dairy Lagoon

    PubMed Central

    Ravva, Subbarao V.; Sarreal, Chester Z.; Mandrell, Robert E.

    2013-01-01

    Surviving predation is a fitness trait of Escherichia coli O157:H7 (EcO157) that provides ample time for the pathogen to be transported from reservoirs (e.g. dairies and feedlots) to farm produce grown in proximity. Ionophore dietary supplements that inhibit rumen protozoa may provide such a selective advantage for EcO157 to proliferate in lagoons as the pathogen is released along with the undigested supplement as manure washings. This study evaluated the fate of an outbreak strain of EcO157, protozoan and bacterial communities in wastewater treated with monensin. Although total protozoa and native bacteria were unaffected by monensin, the time for 90% decrease in EcO157 increased from 0.8 to 5.1 days. 18S and 16S rRNA gene sequencing of wastewater samples revealed that monensin eliminated almost all colpodean and oligohymenophorean ciliates, probably facilitating the extended survival of EcO157. Total protozoan numbers remained high in treated wastewater as monensin enriched 94% of protozoan sequences undetected with untreated wastewater. Monensin stimulated 30-fold increases in Cyrtohymena citrina, a spirotrichean ciliate, and also biflagellate bicosoecids and cercozoans. Sequences of gram-negative Proteobacteria increased from 1% to 46% with monensin, but gram-positive Firmicutes decreased from 93% to 46%. It is noteworthy that EcO157 numbers increased significantly (P<0.01) in Sonneborn medium containing monensin, probably due to monensin-inhibited growth of Vorticella microstoma (P<0.05), a ciliate isolated from wastewater. We conclude that dietary monensin inhibits ciliate protozoa that feed on EcO157. Feed supplements or other methods that enrich these protozoa in cattle manure could be a novel strategy to control the environmental dissemination of EcO157 from dairies to produce production environments. PMID:23349969

  8. Transportation and lairage environment effects on prevalence, numbers, and diversity of Escherichia coli O157:H7 on hides and carcasses of beef cattle at processing.

    PubMed

    Arthur, Terrance M; Bosilevac, Joseph M; Brichta-Harhay, Dayna M; Guerini, Michael N; Kalchayanand, Norasak; Shackelford, Steven D; Wheeler, Tommy L; Koohmaraie, Mohammad

    2007-02-01

    Hide has been established as the main source of carcass contamination during cattle processing; therefore, it is crucial to minimize the amount of Escherichia coli O157:H7 on cattle hides before slaughter. Several potential sources of E. coli O157: H7 are encountered during transportation and in the lairage environment at beef-processing facilities that could increase the prevalence and numbers of E. coli O157:H7 on the hides of cattle. On three separate occasions, samples were obtained from cattle at the feedlot and again after cattle were stunned and exsanguinated at the processing plant (286 total animals). The prevalence of E. coli O157:H7 on hides increased from 50.3 to 94.4% between the time cattle were loaded onto tractor-trailers at the feedlot and the time hides were removed in the processing plant. Before transport, nine animals had E. coli O157:H7 in high numbers (> 0.4 CFU/cm2) on their hides. When sampled at the slaughter facility, the number of animals with high hide numbers had increased to 70. Overall, only 29% of the E. coli O157:H7 isolates collected postharvest (221 of 764) matched pulsed-field gel electrophoresis types collected before transport. The results of this study indicate that transport to and lairage at processing plants can lead to increases in the prevalence and degree of E. coli O157:H7 contamination on hides and the number of E. coli O157:H7 pulsed-field gel electrophoresis types associated with the animals. More study is needed to confirm the mechanism by which additional E. coli O157:H7 strains contaminate cattle hides during transport and lairage and to design interventions to prevent this contamination. PMID:17340859

  9. Escherichia coli O157:H7 lacking qseBC encoded quorum sensing system outcompetes the parent strain in colonization of cattle intestine

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The qseBC encoded quorum-sensing system (QS) regulates motility of enterohemorrhagic Escherichia coli (EHEC) O157:H7 in response to bacterial autoinducer-3 (AI-3) and mammalian stress hormones epinephrine (E) and norepinephrine (NE). The qseC gene encodes a sensory kinase that post-autophosphorylati...

  10. Leakage of Intracellular UV Materials of High Hydrostatic Pressure-Injured Escherichia Coli O157:H7 Strains in Tomato Juice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effect of high hydrostatic pressure (HHP) treatment on inactivation, injury and recovery of Salmonella Enteritidis and Escherichia coli O157:H7 cocktail inoculated in tomato juice (pH 4.1) and phosphate buffer saline (PBS. pH 7.2) at 8.0 log CFU/ml and treated at 350, 400, 450 MPa for 20 min at ...

  11. Sequence of colonization determines the composition of mixed biofilms by Escherichia coli O157:H7 and O111:H8 strains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bacterial biofilms are one of the potential sources of cross-contamination in food processing environments. Shiga-toxin producing Escherichia coli (STEC) O157:H7 and O111:H8 are important foodborne pathogens capable of forming biofilms, and the coexistence of these two STEC serotypes has been detec...

  12. [Therapeutic effects of antibiotics against enterohemorrhagic Escherichia coli (EHEC) O157:H7 (O157) infection: in vivo analysis using germfree mice].

    PubMed

    Sawamura, S; Tanaka, K; Koga, Y

    1999-10-01

    Though O157 can cause a life-threatening diseases, the therapeutic protocol using antibiotics for the infection is still controversial. Main reasons for hesitating the uses of antibiotics for the infection is their possibility to enhance the release of verotoxins (VT). We have recently established the mouse model of O157 infection using germfree mice. Using this animal model of O157 infection, we examined therapeutic efficacy of antibiotics. Fosfomycin (FOM) and norfloxacin (NFLX) were selected for in vivo examination, because of their lower MIC under anaerobic condition (MIC:FOM = 0.78; NFLX = 0.10 microgram/ml) than those of the other antibiotics including kanamycin, doxycycline, minocycline, choramphenicol, cefaclor and ampicilin. When germfree BALB/c mice were orally infected with 1 x 10(5)CFU of O157 (clinically-isolated strain, TI001) at day 0, all mice died at 8 to 9 d after the infection. Oral treatment of the mice with FOM (500 mg/kg/d, twice a day) or NFLX (50 mg/kg/d, twice a day) everyday for 5 days starting at 3 hr after the infection significantly improved the survival rate from 0% to 83.3%, and 100%, respectively. VT could not be detected in the feces of the mice in either groups, suggesting that neither of these antibiotics enhanced the release of VT. Interestingly, when FOM treatment was started at 3, 6, 12 or 24 hr after the infection, the survival rate was 100%, 100%, 0% and 0%, respectively. Thus, in conclusion, FOM and NFLX are both useful as the therapeutic agents for O157 infection. However, the treatment should be started in the early phase after the infection. PMID:10565122

  13. Altered protozoan and bacterial communities and survival of Escherichia coli O157:H7 in monensin-treated dairy wastewater from a dairy lagoon

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We determined the role of native protozoa in controlling the populations of Escherichia coli O157:H7 (EcO157) in wastewater from dairy lagoons as both protozoa and EcO157 are released into lagoons through manure washings. We monitored the fate of an outbreak strain of EcO157 in wastewater treated wi...

  14. Incidence and Tracking of Escherichia coli O157:H7 in a Major Produce Production Region in California

    PubMed Central

    Cooley, Michael; Carychao, Diana; Crawford-Miksza, Leta; Jay, Michele T.; Myers, Carol; Rose, Christopher; Keys, Christine; Farrar, Jeff; Mandrell, Robert E.

    2007-01-01

    Fresh vegetables have become associated with outbreaks caused by Escherichia coli O157:H7 (EcO157). Between 1995–2006, 22 produce outbreaks were documented in the United States, with nearly half traced to lettuce or spinach grown in California. Outbreaks between 2002 and 2006 induced investigations of possible sources of pre-harvest contamination on implicated farms in the Salinas and San Juan valleys of California, and a survey of the Salinas watershed. EcO157 was isolated at least once from 15 of 22 different watershed sites over a 19 month period. The incidence of EcO157 increased significantly when heavy rain caused an increased flow rate in the rivers. Approximately 1000 EcO157 isolates obtained from cultures of>100 individual samples were typed using Multi-Locus Variable-number-tandem-repeat Analysis (MLVA) to assist in identifying potential fate and transport of EcO157 in this region. A subset of these environmental isolates were typed by Pulse Field Gel Electrophoresis (PFGE) in order to make comparisons with human clinical isolates associated with outbreak and sporadic illness. Recurrence of identical and closely related EcO157 strains from specific locations in the Salinas and San Juan valleys suggests that transport of the pathogen is usually restricted. In a preliminary study, EcO157 was detected in water at multiple locations in a low-flow creek only within 135 meters of a point source. However, possible transport up to 32 km was detected during periods of higher water flow associated with flooding. During the 2006 baby spinach outbreak investigation, transport was also detected where water was unlikely to be involved. These results indicate that contamination of the environment is a dynamic process involving multiple sources and methods of transport. Intensive studies of the sources, incidence, fate and transport of EcO157 near produce production are required to determine the mechanisms of pre-harvest contamination and potential risks for human

  15. Incidence and tracking of Escherichia coli O157:H7 in a major produce production region in California.

    PubMed

    Cooley, Michael; Carychao, Diana; Crawford-Miksza, Leta; Jay, Michele T; Myers, Carol; Rose, Christopher; Keys, Christine; Farrar, Jeff; Mandrell, Robert E

    2007-01-01

    Fresh vegetables have become associated with outbreaks caused by Escherichia coli O157:H7 (EcO157). Between 1995-2006, 22 produce outbreaks were documented in the United States, with nearly half traced to lettuce or spinach grown in California. Outbreaks between 2002 and 2006 induced investigations of possible sources of pre-harvest contamination on implicated farms in the Salinas and San Juan valleys of California, and a survey of the Salinas watershed. EcO157 was isolated at least once from 15 of 22 different watershed sites over a 19 month period. The incidence of EcO157 increased significantly when heavy rain caused an increased flow rate in the rivers. Approximately 1000 EcO157 isolates obtained from cultures of>100 individual samples were typed using Multi-Locus Variable-number-tandem-repeat Analysis (MLVA) to assist in identifying potential fate and transport of EcO157 in this region. A subset of these environmental isolates were typed by Pulse Field Gel Electrophoresis (PFGE) in order to make comparisons with human clinical isolates associated with outbreak and sporadic illness. Recurrence of identical and closely related EcO157 strains from specific locations in the Salinas and San Juan valleys suggests that transport of the pathogen is usually restricted. In a preliminary study, EcO157 was detected in water at multiple locations in a low-flow creek only within 135 meters of a point source. However, possible transport up to 32 km was detected during periods of higher water flow associated with flooding. During the 2006 baby spinach outbreak investigation, transport was also detected where water was unlikely to be involved. These results indicate that contamination of the environment is a dynamic process involving multiple sources and methods of transport. Intensive studies of the sources, incidence, fate and transport of EcO157 near produce production are required to determine the mechanisms of pre-harvest contamination and potential risks for human

  16. Verotoxin-producing Escherichia coli in Spain: prevalence, serotypes, and virulence genes of O157:H7 and non-O157 VTEC in ruminants, raw beef products, and humans.

    PubMed

    Blanco, Jorge; Blanco, Miguel; Blanco, Jesus E; Mora, Azucena; González, Enrique A; Bernárdez, Maria I; Alonso, Maria P; Coira, Amparo; Rodriguez, Asuncion; Rey, Joaquin; Alonso, Juan M; Usera, Miguel A

    2003-04-01

    In Spain, as in many other countries, verotoxin-producing Escherichia coli (VTEC) strains have been frequently isolated from cattle, sheep, and foods. VTEC strains have caused seven outbreaks in Spain (six caused by E. coli O157:H7 and one by E. coli O111:H- [nonmotile]) in recent years. An analysis of the serotypes indicated serological diversity. Among the strains isolated from humans, serotypes O26:H11, O111:H-, and O157:H7 were found to be more prevalent. The most frequently detected serotypes in cattle were O20:H19, O22:H8, O26:H11, O77:H41, O105:H18, O113:H21, O157:H7, O171:H2, and OUT (O untypeable):H19. Different VTEC serotypes (e.g., O5:H-, O6:H10, O91:H-, O117:H-, O128:H-, O128:H2, O146:H8, O146:H21, O156:H-, and OUT:H21) were found more frequently in sheep. These observations suggest a host serotype specificity for some VTEC. Numerous bovine and ovine VTEC serotypes detected in Spain were associated with human illnesses, confirming that ruminants are important reservoirs of pathogenic VTEC. VTEC can produce one or two toxins (VT1 and VT2) that cause human illnesses. These toxins are different proteins encoded by different genes. Another virulence factor expressed by VTEC is the protein intimin that is responsible for intimate attachment of VTEC and effacing lesions in the intestinal mucosa. This virulence factor is encoded by the chromosomal gene eae. The eae gene was found at a much less frequency in bovine (17%) and ovine (5%) than in human (45%) non-O157 VTEC strains. This may support the evidence that the eae gene contributes significantly to the virulence of human VTEC strains and that many animal non-O157 VTEC strains are less pathogenic to humans. PMID:12671177

  17. Evaluation of fourier transform infrared (FT-IR) spectroscopy and chemometrics as a rapid approach for subtyping E. coli O157:H7 isolates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The importance of tracking outbreaks of foodborne illness and the emergence of new virulent subtypes of foodborne pathogens have created the need for rapid and reliable subtyping methods for Escherichia coli O157:H7. Fourier transform infrared (FT-IR) spectroscopy coupled with multivariate statistic...

  18. Influence of wet distiller's grains on prevalence of E. coli O157:H7 and Salmonella in feedlot cattle and antimicrobial susceptibility of generic E. coli isolates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The current research examined the inclusion of 20% wet distiller’s grains (WDG) fed with steam-flaked (SFC) or dry-rolled (DRC) corn in diets fed to feedlot cattle on fecal prevalence of E. coli O157:H7 and Salmonella. Crossbred beef heifers (n = 272; average initial body weight (BW) = 354 kg) were...

  19. ISOLATION OF SALMONELLA ENTERICA AND SHIGA-TOXIGENIC ESCHERICHIA COLI O157 FROM FECES OF ANIMALS IN PUBLIC CONTACT AREAS OF UNITED STATES ZOOLOGICAL PARKS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fecal prevalence of subclinical Salmonella and Shiga-toxigenic Escherichia coli O157 among animals in human-animal contact exhibits at United States Association of Zoos and Aquariums-accredited institutions was estimated to assess public health risk. Prevalence was less than 0.6% for both zoonotic p...

  20. Genome sequence of two separate Escherichia coli O157:H7 isolates from lineage 2 confirm disruption in bacteriophage encoding Shiga toxin 2

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The existence of two separate lineages of E. coli O157:H7 has previously been reported, and research indicates that one of these lineages (lineage I) might be more pathogenic towards human hosts.We have previously shown that the more pathogenic lineage expresses higher levels of Shiga toxin 2 (Stx2)...

  1. Distinct transcriptional profiles and phenotypes exhibited by Escherichia coli O157:H7 isolates related to the 2006 spinach-associated outbreak

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In 2006, an outbreak of Escherichia coli O157:H7 was linked to the consumption of ready-to-eat bagged spinach. The likely sources of pre-harvest spinach contamination were soil and water that became contaminated via cattle or feral pigs in the proximity of the spinach fields. In this study, we compa...

  2. Geographic Divergence of Bovine and Human Shiga Toxin–Producing Escherichia coli O157:H7 Genotypes, New Zealand1

    PubMed Central

    Cookson, Adrian L.; Campbell, Donald M.; Duncan, Gail E.; Prattley, Deborah; Carter, Philip; Besser, Thomas E.; Shringi, Smriti; Hathaway, Steve; Marshall, Jonathan C.; French, Nigel P.

    2014-01-01

    Shiga toxin-producing Escherichia coli (STEC) O157:H7 is a zoonotic pathogen of public health concern worldwide. To compare the local and large-scale geographic distributions of genotypes of STEC O157:H7 isolates obtained from various bovine and human sources during 2008–2011, we used pulsed-field gel electrophoresis and Shiga toxin–encoding bacteriophage insertion (SBI) typing. Using multivariate methods, we compared isolates from the North and South Islands of New Zealand with isolates from Australia and the United States. The STEC O157:H7 population structure differed substantially between the 2 islands and showed evidence of finer scale spatial structuring, which is consistent with highly localized transmission rather than disseminated foodborne outbreaks. The distribution of SBI types differed markedly among isolates from New Zealand, Australia, and the United States. Our findings also provide evidence for the historic introduction into New Zealand of a subset of globally circulating STEC O157:H7 strains that have continued to evolve and be transmitted locally between cattle and humans. PMID:25568924

  3. Comparative analysis of super-shedder strains of Escherichia coli O157:H7 reveals distinctive genomic features and a strongly aggregative adherent phenotype on bovine rectoanal junction squamous epithelial cells

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Shiga toxin-producing Escherichia coli O157:H7 (O157) are significant foodborne pathogens and a serious threat to public health worldwide. The major reservoirs of O157 are asymptomatic cattle which harbor the organism in the terminal recto-anal junction (RAJ). Some colonized animals, referred to as ...

  4. Isolation of Salmonella enterica and Shiga-Toxigenic Escherichia coli O157 from Feces of Animals in Public Contact Areas of United States Zoological Parks▿

    PubMed Central

    Keen, James E.; Durso, Lisa M.; Meehan, Thomas P.

    2007-01-01

    The fecal prevalence of subclinical Salmonella enterica and Shiga-toxigenic Escherichia coli O157 among animals in human-animal contact exhibits at institutions in the United States accredited by the Association of Zoos and Aquariums was estimated to assess public health risk. The prevalence was less than 0.6% for both zoonotic pathogens among 997 animals sampled at 36 exhibits. PMID:17071798

  5. Assessment of Virulence Factors Characteristic of Human Escherichia coli Pathotypes and Antimicrobial Resistance in O157:H7 and Non-O157:H7 Isolates from Livestock in Spain

    PubMed Central

    Cabal, A.; Gómez-Barrero, S.; Porrero, C.; Bárcena, C.; López, G.; Cantón, R.; Gortázar, C.; Domínguez, L.

    2013-01-01

    The distribution of virulence factors (VFs) typical of diarrheagenic Escherichia coli and the antimicrobial resistance (AMR) profiles were assessed in 780 isolates from healthy pigs, broilers, and cattle from Spain. VF distribution was broader than expected, although at low prevalence for most genes, with AMR being linked mainly to host species. PMID:23603685

  6. [Survival of VTEC O157 and non-O157 in water troughs and bovine feces].

    PubMed

    Polifroni, Rosana; Etcheverría, Analía I; Arroyo, Guillermo H; Padola, Nora L

    2014-01-01

    Verotoxin-producing Escherichia coli (VTEC) is the etiologic agent of hemolytic-uremic syndrome (HUS), which typically affects children ranging in age from six months to five years old. Transmission is produced by consumption of contaminated food, by direct contact with animals or the environment and from person to person. In previous studies we determined that the environment of a dairy farm is a non-animal reservoir; thus, we proposed to study the survival of 4 VTEC isolates (O20:H19; O91:H21; O157:H7 and O178:H19) in sterile water troughs and bovine feces by viable bacteria count and detection of virulence genes by PCR. It was demonstrated that the survival of different VTEC isolates (O157 and non-O157) varied in terms of their own characteristics as well as of the environmental conditions where they were found. The main differences between isolates were their survival time and the maximal counts reached. The competitive and adaptive characteristics of some isolates increase the infection risk for people that are visiting or working on a farm, as well as the risk for reinfection of the animals and food contamination. PMID:25011597

  7. A longitudinal study of risk factors for shedding of VTEC O157 by young cattle in herds with known E. coli O157 carriage.

    PubMed

    Smith, R P; Pollitt, W J; Paiba, G A

    2016-07-01

    A longitudinal study in England and Wales of two dairy, five beef-fattener and three beef-suckler herds was carried out to identify risk factors for young cattle excreting verocytotoxin-producing Escherichia coli O157 (VTEC O157). A total of 1383 cattle, selected into cohorts at 0-24 months were sampled between March 2000 and February 2001. Mixed-effects logistic regression was employed to identify significant associations between VTEC O157 isolation from rectal faecal samples and explanatory factors (P < 0·001 unless shown). The results revealed a positive association with feeding root crops and a negative association with animals fed silage, milk (P = 0·001) or grain (P = 0·027). Cattle in suckler herds (P = 0·001) and those changing group between sampling visits were identified as negatively associated with VTEC O157 presence. The recovery of VTEC O157 varied throughout the year. However, the winter period from December to February was a risk factor in the multivariable analysis. Cattle in pens were 4·7 times more likely to shed VTEC O157 than those group-housed or at pasture. VTEC O157 detected in pooled environmental faecal pats and biofilm of the water supply within a group's enclosure were positively associated with an animal's VTEC O157 status in the multivariable logistic regression, as was detection of VTEC O157 in the pooled faecal pats at the previous visit. PMID:26830233

  8. Utility of Whole-Genome Sequencing of Escherichia coli O157 for Outbreak Detection and Epidemiological Surveillance

    PubMed Central

    Allison, Lesley; Ward, Melissa; Dallman, Timothy J.; Clark, Richard; Fawkes, Angie; Murphy, Lee; Hanson, Mary

    2015-01-01

    Detailed laboratory characterization of Escherichia coli O157 is essential to inform epidemiological investigations. This study assessed the utility of whole-genome sequencing (WGS) for outbreak detection and epidemiological surveillance of E. coli O157, and the data were used to identify discernible associations between genotypes and clinical outcomes. One hundred five E. coli O157 strains isolated over a 5-year period from human fecal samples in Lothian, Scotland, were sequenced with the Ion Torrent Personal Genome Machine. A total of 8,721 variable sites in the core genome were identified among the 105 isolates; 47% of the single nucleotide polymorphisms (SNPs) were attributable to six “atypical” E. coli O157 strains and included recombinant regions. Phylogenetic analyses showed that WGS correlated well with the epidemiological data. Epidemiological links existed between cases whose isolates differed by three or fewer SNPs. WGS also correlated well with multilocus variable-number tandem repeat analysis (MLVA) typing data, with only three discordant results observed, all among isolates from cases not known to be epidemiologically related. WGS produced a better-supported, higher-resolution phylogeny than MLVA, confirming that the method is more suitable for epidemiological surveillance of E. coli O157. A combination of in silico analyses (VirulenceFinder, ResFinder, and local BLAST searches) were used to determine stx subtypes, multilocus sequence types (15 loci), and the presence of virulence and acquired antimicrobial resistance genes. There was a high level of correlation between the WGS data and our routine typing methods, although some discordant results were observed, mostly related to the limitation of short sequence read assembly. The data were used to identify sublineages and clades of E. coli O157, and when they were correlated with the clinical outcome data, they showed that one clade, Ic3, was significantly associated with severe disease. Together

  9. Differential Virulence of Clinical and Bovine-Biased Enterohemorrhagic Escherichia coli O157:H7 Genotypes in Piglet and Dutch Belted Rabbit Models

    PubMed Central

    Shringi, Smriti; García, Alexis; Lahmers, Kevin K.; Potter, Kathleen A.; Muthupalani, Sureshkumar; Swennes, Alton G.; Hovde, Carolyn J.; Call, Douglas R.; Fox, James G.

    2012-01-01

    Enterohemorrhagic Escherichia coli O157:H7 (EHEC O157) is an important cause of food and waterborne illness in the developed countries. Cattle are a reservoir host of EHEC O157 and a major source of human exposure through contaminated meat products. Shiga toxins (Stxs) are an important pathogenicity trait of EHEC O157. The insertion sites of the Stx-encoding bacteriophages differentiate EHEC O157 isolates into genogroups commonly isolated from cattle but rarely from sick humans (bovine-biased genotypes [BBG]) and those commonly isolated from both cattle and human patients (clinical genotypes [CG]). Since BBG and CG share the cardinal virulence factors of EHEC O157 and are carried by cattle at similar prevalences, the infrequent occurrence of BBG among human disease isolates suggests that they may be less virulent than CG. We compared the virulence potentials of human and bovine isolates of CG and BBG in newborn conventional pig and weaned Dutch Belted rabbit models. CG-challenged piglets experienced severe disease accompanied by early and high mortality compared to BBG-challenged piglets. Similarly, CG-challenged rabbits were likely to develop lesions in kidney and intestine compared with the BBG-challenged rabbits. The CG strains used in this study carried stx2 and produced significantly higher amounts of Stx, whereas the BBG strains carried the stx2c gene variant only. These results suggest that BBG are less virulent than CG and that this difference in virulence potential is associated with the Stx2 subtype(s) carried and/or the amount of Stx produced. PMID:22025512

  10. High-Quality Draft Genome Sequences for Five Non-O157 Shiga Toxin-Producing Escherichia coli Strains Generated with PacBio Sequencing and Optical Maps.

    PubMed

    Lindsey, Rebecca L; Rowe, Lori; Garcia-Toledo, Lisley; Loparev, Vladimir; Knipe, Kristen; Stripling, Devon; Martin, Haley; Trees, Eija; Juieng, Phalasy; Batra, Dhwani; Strockbine, Nancy

    2016-01-01

    Shiga toxin-producing Escherichia coli (STEC) is a foodborne pathogen. We report here the high-quality draft whole-genome sequences of five STEC strains isolated from clinical cases in the United States. This report is for STEC of serotypes O55:H7, O79:H7, O91:H14, O153:H2, and O156:H25. PMID:27365352

  11. High-Quality Draft Genome Sequences for Five Non-O157 Shiga Toxin-Producing Escherichia coli Strains Generated with PacBio Sequencing and Optical Maps

    PubMed Central

    Rowe, Lori; Garcia-Toledo, Lisley; Loparev, Vladimir; Knipe, Kristen; Stripling, Devon; Martin, Haley; Trees, Eija; Juieng, Phalasy; Batra, Dhwani; Strockbine, Nancy

    2016-01-01

    Shiga toxin-producing Escherichia coli (STEC) is a foodborne pathogen. We report here the high-quality draft whole-genome sequences of five STEC strains isolated from clinical cases in the United States. This report is for STEC of serotypes O55:H7, O79:H7, O91:H14, O153:H2, and O156:H25. PMID:27365352

  12. Gram-negative bacterial isolates from fresh-cut processing plants enhance the presence of Escherichia Coli O157:H7 in dual-species biofilms

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biofilms formed by resident microflora may provide a microenvironment for foodborne bacterial pathogens to survive and cause cross-contamination in fresh-cut processing and handling facilities. The objective of this study is to determine the impact of individual bacteria strains isolated from two l...

  13. Effect of Lactobacillus Strains on Intestinal Microflora and Mucosa Immunity in Escherichia coli O157:H7-Induced Diarrhea in Mice.

    PubMed

    Bian, Xin; Wang, Ting-Ting; Xu, Min; Evivie, Smith Etareri; Luo, Guang-Wen; Liang, Hong-Zhang; Yu, Shang-Fu; Huo, Gui-Cheng

    2016-07-01

    This study investigated the effects of KLDS 1.8701 and AD1 administrations by gavage on intestinal microflora and mucosal immunity in diarrhea mice infected by Escherichia coli O157:H7 compared to normal mice. The levels of E. coli, Enterobacteria, and Enterococcus decreased significantly (P < 0.05), while viable counts of Lactobacilli and Bifidobacterium increased in diarrhea mice. Moreover, KLDS 1.8701 and AD1 improved secretion of secretory immunoglobulin A and enhanced the levels of interferon-γ and interleukin. Results indicate that KLDS 1.8701 and AD1 could effectively alleviate diarrhea in mice via modulation of intestinal microflora and improve the function of immune system. The study on the effect of KLDS1.8701 and AD1 supplementation in human flora-associated animal models was recommended. PMID:27025726

  14. Internalization of Escherichia Coli O157:H7 by Bovine Rectal Epithelial Cells

    PubMed Central

    Sheng, Haiqing; Wang, Jing; Lim, Ji Youn; Davitt, Christine; Minnich, Scott A.; Hovde, Carolyn J.

    2011-01-01

    Escherichia coli O157:H7 (O157) causes human diarrheal disease and healthy cattle are its primary reservoir. O157 colonize the bovine epithelial mucosa at the recto-anal junction (RAJ). Previous studies show that O157 at this site are not eliminated by aggressive interventions including applications of O157-specific lytic bacteriophages and other bactericidal agents. We hypothesize that some O157 at the RAJ mucosa are protected from these killing agents by host cell internalization. To test this hypothesis, rectal biopsies from O157 culture positive and negative cattle were analyzed by fluorescent microscopy and subjected to gentamicin protection assays. GFP-labeled bacteria were found located deep within the tissue crypts and a small number of O157 were recovered from rectal biopsies after gentamicin treatment. Primary bovine rectal epithelial (PBRE) cell cultures were incubated with O157 and subjected to gentamicin protection assays. Strains ATCC 43895, 43894, Sakai, and WSU180 entered the PBRE cells with different levels of efficiency ranging from 0.18 to 19.38% of the inocula. Intracellular bacteria were confirmed to be within membrane-bounded vacuoles by electron microscopy. Cytochalasin D curtailed internalization of O157 indicating internalization was dependent on eukaryotic microfilament assembly. Strain ATCC 43895 exhibited the highest efficiency of internalization and survived for at least 24 h within PBRE cells. Deletion mutation of intimin or its receptor in ATCC 43895 did not reduce bacterial internalization. This strain produced more biofilm than the others tested. Retrospective analysis of cattle challenged with two O157 strains, showed ATCC 43895, the most efficient at host cell internalization, was most persistent. PMID:21687423

  15. Non-O157 Shiga Toxin-Producing E. coli Associated with Muscle Foods

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Escherichia coli strains that produce Shiga toxins, referred to as Shiga toxin-producing E. coli (STEC) or verotoxigenic E. coli (VTEC), cause hemorrhagic colitis (HC) and hemolytic uremic syndrome (HUS). E. coli O157:H7 is the most common cause of STEC infection; however, numerous non-O157 STECs b...

  16. Antibacterial activity of cinnamaldehyde and Sporan against Escherichia coli O157:H7 and Salmonella

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The in vitro antimicrobial effect of cinnamaldehyde and Sporan in combination with acetic acid against E. coli O157:H7 and Salmonella was investigated. A five strain cocktail of E. coli O157:H7 and Salmonella were inoculated in Luria-Bertoni broth (LB broth, 7 log CFU ml-1) containing cinnamaldehyde...

  17. Identification of Escherichia coli O157 by Using a Novel Colorimetric Detection Method with DNA Microarrays

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Shiga toxin-producing Escherichia coli O157:H7 is a leading cause of foodborne illness worldwide. To evaluate better methods to rapidly detect and genotype E. coli O157 strains, the present study evaluated the use of ampliPHOX, a novel colorimetric detection method based on photopolymerization, for...

  18. Characterization of the pathogenome and phylogenomic classification of enteropathogenic Escherichia coli of the O157:non-H7 serotypes

    PubMed Central

    Sanjar, Fatemeh; Rusconi, Brigida; Hazen, Tracy H.; Koenig, Sara S.K.; Mammel, Mark K.; Feng, Peter C.H.; Rasko, David A.; Eppinger, Mark

    2015-01-01

    Escherichia coli of the O157 serogroup are comprised of a diverse collection of more than 100 O157:non-H7 serotypes that are found in the environment, animal reservoir and infected patients and some have been linked to severe outbreaks of human disease. Among these, the enteropathogenic E. coli O157:non-H7 serotypes carry virulence factors that are hallmarks of enterohemorrhagic E. coli, such as causing attaching and effacing lesions during human gastrointestinal tract infections. Given the shared virulence gene pool between O157:H7 and O157:non-H7 serotypes, our objective was to examine the prevalence of virulence traits of O157:non-H7 serotypes within and across their H-serotype and when compared to other E. coli pathovars. We sequenced six O157:non-H7 genomes complemented by four genomes from public repositories in an effort to determine their virulence state and genetic relatedness to the highly pathogenic enterohemorrhagic O157:H7 lineage and its ancestral O55:H7 serotype. Whole-genome-based phylogenomic analysis and molecular typing is indicative of a non-monophyletic origin of the heterogeneous O157:non-H7 serotypes that are only distantly related to the O157:H7 serotype. The availability of multiple genomes enables robust phylogenomic placement of these strains into their evolutionary context, and the assessment of the pathogenic potential of the O157:non-H7 strains in causing human disease. PMID:25962987

  19. Probing genomic diversity and evolution of Escherichia coli O157 by single nucleotide polymorphisms

    PubMed Central

    Zhang, Wei; Qi, Weihong; Albert, Thomas J.; Motiwala, Alifiya S.; Alland, David; Hyytia-Trees, Eija K.; Ribot, Efrain M.; Fields, Patricia I.; Whittam, Thomas S.; Swaminathan, Bala

    2006-01-01

    Infections by Shiga toxin-producing Escherichia coli O157:H7 (STEC O157) are the predominant cause of bloody diarrhea and hemolytic uremic syndrome in the United States. In silico comparison of the two complete STEC O157 genomes (Sakai and EDL933) revealed a strikingly high level of sequence identity in orthologous protein-coding genes, limiting the use of nucleotide sequences to study the evolution and epidemiology of this bacterial pathogen. To systematically examine single nucleotide polymorphisms (SNPs) at a genome scale, we designed comparative genome sequencing microarrays and analyzed 1199 chromosomal genes (a total of 1,167,948 bp) and 92,721 bp of the large virulence plasmid (pO157) of eleven outbreak-associated STEC O157 strains. We discovered 906 SNPs in 523 chromosomal genes and observed a high level of DNA polymorphisms among the pO157 plasmids. Based on a uniform rate of synonymous substitution for Escherichia coli and Salmonella enterica (4.7 × 10−9 per site per year), we estimate that the most recent common ancestor of the contemporary β-glucuronidase-negative, non-sorbitolfermenting STEC O157 strains existed ca. 40 thousand years ago. The phylogeny of the STEC O157 strains based on the informative synonymous SNPs was compared to the maximum parsimony trees inferred from pulsed-field gel electrophoresis and multilocus variable numbers of tandem repeats analysis. The topological discrepancies indicate that, in contrast to the synonymous mutations, parts of STEC O157 genomes have evolved through different mechanisms with highly variable divergence rates. The SNP loci reported here will provide useful genetic markers for developing high-throughput methods for fine-resolution genotyping of STEC O157. Functional characterization of nucleotide polymorphisms should shed new insights on the evolution, epidemiology, and pathogenesis of STEC O157 and related pathogens. PMID:16606700

  20. Detection of Escherichia Coli O157:H7 in Fecal Samples in Meat Goats

    ERIC Educational Resources Information Center

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

    2004-01-01

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

  1. Phage Types and Genotypes of Shiga Toxin-Producing Escherichia coli O157 in Finland

    PubMed Central

    Saari, Marjut; Cheasty, Thomas; Leino, Kirsikka; Siitonen, Anja

    2001-01-01

    This study examined Shiga toxin-producing Escherichia coli (STEC) O157, using phage typing, pulsed-field gel electrophoresis, and typing of Shiga toxin variant genes by PCR with restriction fragment length polymorphism in an epidemiological survey of STEC O157 isolated from humans in Finland between 1990 and 1999. PMID:11230443

  2. Effect of four probiotic strains and Escherichia coli O157:H7 on tight junction integrity and cyclo-oxygenase expression.

    PubMed

    Putaala, Heli; Salusjärvi, Tuomas; Nordström, Malin; Saarinen, Markku; Ouwehand, Arthur C; Bech Hansen, Egon; Rautonen, Nina

    2008-01-01

    Controversy exists as to whether contact between a probiotic bacterial cell and an epithelial cell in the gut is needed to confer beneficial effects of probiotics, or whether metabolites from probiotics are sufficient to cause this effect. To address this question, Caco-2 cells were treated with cell-free supernatants of four probiotics, Bifidobacterium lactis 420, Bifidobacterium lactis HN019, Lactobacillus acidophilus NCFM, Lactobacillus salivarius Ls-33, and by a cell-free supernatant of a pathogenic bacteria, Escherichia coli O157:H7 (EHEC). Tight junction integrity as well as expression of cyclo-oxygenases, which are prostaglandin-producing enzymes, were measured. Probiotic-specific as well as EHEC-specific effects on tight junction integrity and cyclo-oxygenase expression were evident, indicating that live bacterial cells were not necessary for the manifestation of the effects. B. lactis 420 cell-free supernatant increased tight junction integrity, while EHEC cell-free supernatant induced damage on tight junctions. In general, EHEC and probiotics had opposite effects upon cyclo-oxygenase expression. Furthermore, B. lactis 420 cell-free supernatant protected the tight junctions from EHEC-induced damage when administered prior to the cell-free supernatant of EHEC. These results indicate that probiotics produce bioactive metabolites, suggesting that consumption of specific probiotic bacteria might be beneficial in protecting intestinal epithelial cells from the deleterious effects of pathogenic bacteria. PMID:18783733

  3. [Investigation of verotoxigenic Escherichia coli O157:H7 incidence in gastroenteritis patients].

    PubMed

    Erdoğan, Haluk; Levent, Belkıs; Erdoğan, Aşkın; Güleşen, Revasiye; Arslan, Hande

    2011-07-01

    Escherichia coli O157:H7 is the most common serotype among verotoxigenic E.coli (VTEC) strains that cause haemolytic uremic syndrome. Although sporadic VTEC cases originating from Turkey and small outbreaks have been reported from our country, VTEC has not been routinely investigated in most of the diagnostic microbiology laboratories in Turkey and studies related to this topic are limited. In this study, the incidence of E.coli O157:H7 in patients who were admitted to Alanya Research and Application Hospital of Baskent University with the complaints of acute gastroenteritis between September 2005 and September 2008, was investigated. Stool samples collected from 1815 diarrheal patients (of them 50.5% were male; 49.3% were ? 5 years old; 10.2% were tourists) were evaluated initially by direct microscopy and then inoculated to hectoen enteric agar, EMB agar, Skirrow agar and cefixime tellurite sorbitol MacConkey (CT-SMC) agar media for cultivation. The sorbitol-negative colonies which were compatible with E.coli according to the conventional methods were tested with E.coli polyvalent and 0157 and H7 monovalent antisera and agglutination positive strains were also investigated for verotoxin production in Vero cell cultures. VTEC RPLA toxin detection kit (Oxoid, UK) was used for further identification of toxin type of verotoxin positive strains. Fecal leukocytes were detected in 41.3% of the samples in direct microscopy, while 27% (173/639) of the samples were also found positive for amoeba antigen, 6% (24/396) for rotavirus antigen, 1.2% (22/1815) for Salmonella spp., 0.6% (11/1815) for Shigella spp., 0.2% (4/1815) for Giardia trophozoites and 0.06% (1/1815) for Campylobacter jejuni. The isolation rate of sorbitol-negative E.coli strains was %0.8 (14/1815), and two of them were identified as E.coli O157:H7 by monovalent antisera, and both of them were determined as verotoxin-producers in cell culture. Verotoxin types of those isolates were found as verotoxin 1 in one

  4. A Novel Approach to Investigate Internalization of Escherichia coli O157:H7 in Lettuce and Spinach

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The chromosomal integration of the green fluorescent protein (gfp) gene was successfully accomplished into four nalidixic acid resistant E. coli strains: two O157:H7 strains from produce outbreaks, 4407 and 5279, one O157:H7 strain from a beef-associated outbreak, 86-24h11, and a non-pathogenic comm...

  5. Strain isolated ceramic coatings

    NASA Technical Reports Server (NTRS)

    Tolokan, R. P.; Brady, J. B.; Jarrabet, G. P.

    1985-01-01

    Plasma sprayed ceramic coatings are used in gas turbine engines to improve component temperature capability and cooling air efficiency. A compliant metal fiber strain isolator between a plasma sprayed ceramic coating and a metal substrate improves ceramic durability while allowing thicker coatings for better insulation. Development of strain isolated coatings has concentrated on design and fabrication of coatings and coating evaluation via thermal shock testing. In thermal shock testing, five types of failure are possible: buckling failure im compression on heat up, bimetal type failure, isothermal expansion mismatch failure, mudflat cracking during cool down, and long term fatigue. A primary failure mode for thermally cycled coatings is designated bimetal type failure. Bimetal failure is tensile failure in the ceramic near the ceramic-metal interface. One of the significant benefits of the strain isolator is an insulating layer protecting the metal substrate from heat deformation and thereby preventing bimetal type failure.

  6. Mechanical strain isolator mount

    NASA Technical Reports Server (NTRS)

    James, Gordon E. (Inventor)

    1991-01-01

    Certain devices such as optical instruments must preserve their alignmental integrity while being subjected to mechanical strain. A mechanical strain isolator mount is provided to preserve the alignmental integrity of an alignment sensitive instrument. An alignment sensitive instrument is mounted on a rectangular base. Flexural legs are connected at their proximal ends to the rectangular base. Flexural legs are also spaced parallel to the sides. Mounting pads are connected to the legs at the distal end and the mechanical strain isolator mount is attached to the substrate by means of threaded bolts. When a mounting pad and its respective leg is subjected to lateral strain in either the X or Y direction via the substrate, the respective leg relieves the strain by bending in the direction of the strain. An axial strain on a mounting pad in the Z direction is relieved by a rotational motion of the legs in the direction of the strain. When the substrate is stress free, the flexural legs return to their original condition and thus preserve the original alignment integrity of the alignment sensitive instrument.

  7. Role of glycoside hydrolase genes in sinigrin degradation by E. coli O157:H7.

    PubMed

    Cordeiro, Roniele P; Doria, Juan H; Zhanel, George G; Sparling, Richard; Holley, Richard A

    2015-07-16

    This work examined Escherichia coli O157:H7 strain 02-0304 for putative genes responsible for sinigrin hydrolysis. Sinigrin is a glucosinolate present in Oriental mustard (Brassica juncea), and its hydrolysis is mediated in plants by the enzyme myrosinase. Sinigrin hydrolysis by plant or bacterial myrosinase yields allyl isothiocyanate (AITC) which is bactericidal. In silico analysis using public databases found sequence similarity between plant myrosinase and enzymes encoded by genes from β-glucosidase families in E. coli O157:H7. Specifically, 6-phospho-β-glucosidase encoded by the genes bglA and ascB (family 1), and chbF (family 4) present in E. coli O157:H7 showed the highest similarity. Polymerase chain reaction (PCR) confirmed the presence of bglA, ascB, and chbF in the clinical E. coli strain tested. Disruption of these genes in wild-type E. coli O157:H7 strain 02-0304 using lambda-red replacement created single and double mutants. The relative importance of each gene in the hydrolysis of sinigrin by E. coli O157:H7 was also assessed by comparing gene expression and sinigrin degradation rates among the E. coli O157:H7 wild-type strain and its mutants. The results suggested that the genes bglA and ascB play a substantial role in the degradation of sinigrin by E. coli O157:H7 strain 02-0304. PMID:25897994

  8. Genomic anatomy of Escherichia coli O157:H7 outbreaks.

    PubMed

    Eppinger, Mark; Mammel, Mark K; Leclerc, Joseph E; Ravel, Jacques; Cebula, Thomas A

    2011-12-13

    The rapid emergence of Escherichia coli O157:H7 from an unknown strain in 1982 to the dominant hemorrhagic E. coli serotype in the United States and the cause of widespread outbreaks of human food-borne illness highlights a need to evaluate critically the extent to which genomic plasticity of this important enteric pathogen contributes to its pathogenic potential and its evolution as well as its adaptation in different ecological niches. Aimed at a better understanding of the evolution of the E. coli O157:H7 pathogenome, the present study presents the high-quality sequencing and comparative phylogenomic analysis of a comprehensive panel of 25 E. coli O157:H7 strains associated with three nearly simultaneous food-borne outbreaks of human disease in the United States. Here we present a population genetic analysis of more than 200 related strains recovered from patients, contaminated produce, and zoonotic sources. High-resolution phylogenomic approaches allow the dynamics of pathogenome evolution to be followed at a high level of phylogenetic accuracy and resolution. SNP discovery and study of genome architecture and prophage content identified numerous biomarkers to assess the extent of genetic diversity within a set of clinical and environmental strains. A total of 1,225 SNPs were identified in the present study and are now available for typing of the E. coli O157:H7 lineage. These data should prove useful for the development of a refined phylogenomic framework for forensic, diagnostic, and epidemiological studies to define better risk in response to novel and emerging E. coli O157:H7 resistance and virulence phenotypes. PMID:22135463

  9. Phytic Acid and Sodium Chloride Show Marked Synergistic Bactericidal Effects against Nonadapted and Acid-Adapted Escherichia coli O157:H7 Strains.

    PubMed

    Kim, Nam Hee; Rhee, Min Suk

    2016-02-01

    The synergistic antimicrobial effects of phytic acid (PA), a natural extract from rice bran, plus sodium chloride against Escherichia coli O157:H7 were examined. Exposure to NaCl alone at concentrations up to 36% (wt/wt) for 5 min did not reduce bacterial populations. The bactericidal effects of PA alone were much greater than those of other organic acids (acetic, citric, lactic, and malic acids) under the same experimental conditions (P < 0.05). Combining PA and NaCl under conditions that yielded negligible effects when each was used alone led to marked synergistic effects. For example, whereas 0.4% PA or 3 or 4% NaCl alone had little or no effect on cell viability, combining the two completely inactivated both nonadapted and acid-adapted cells, reducing their numbers to unrecoverable levels (>7-log CFU/ml reduction). Flow cytometry confirmed that PA disrupted the cell membrane to a greater extent than did other organic acids, although the cells remained viable. The combination of PA and NaCl induced complete disintegration of the cell membrane. By comparison, none of the other organic acids acted synergistically with NaCl, and neither did NaCl-HCl solutions at the same pH values as the test solutions of PA plus NaCl. These results suggest that PA has great potential as an effective bacterial membrane-permeabilizing agent, and we show that the combination is a promising alternative to conventional chemical disinfectants. These findings provide new insight into the utility of natural compounds as novel antimicrobial agents and increase our understanding of the mechanisms underlying the antibacterial activity of PA. PMID:26637600

  10. Phytic Acid and Sodium Chloride Show Marked Synergistic Bactericidal Effects against Nonadapted and Acid-Adapted Escherichia coli O157:H7 Strains

    PubMed Central

    Kim, Nam Hee

    2015-01-01

    The synergistic antimicrobial effects of phytic acid (PA), a natural extract from rice bran, plus sodium chloride against Escherichia coli O157:H7 were examined. Exposure to NaCl alone at concentrations up to 36% (wt/wt) for 5 min did not reduce bacterial populations. The bactericidal effects of PA alone were much greater than those of other organic acids (acetic, citric, lactic, and malic acids) under the same experimental conditions (P < 0.05). Combining PA and NaCl under conditions that yielded negligible effects when each was used alone led to marked synergistic effects. For example, whereas 0.4% PA or 3 or 4% NaCl alone had little or no effect on cell viability, combining the two completely inactivated both nonadapted and acid-adapted cells, reducing their numbers to unrecoverable levels (>7-log CFU/ml reduction). Flow cytometry confirmed that PA disrupted the cell membrane to a greater extent than did other organic acids, although the cells remained viable. The combination of PA and NaCl induced complete disintegration of the cell membrane. By comparison, none of the other organic acids acted synergistically with NaCl, and neither did NaCl-HCl solutions at the same pH values as the test solutions of PA plus NaCl. These results suggest that PA has great potential as an effective bacterial membrane-permeabilizing agent, and we show that the combination is a promising alternative to conventional chemical disinfectants. These findings provide new insight into the utility of natural compounds as novel antimicrobial agents and increase our understanding of the mechanisms underlying the antibacterial activity of PA. PMID:26637600

  11. Effects of acid adaptation, product pH, and heating on survival of Escherichia coli O157:H7 in pepperoni.

    PubMed

    Riordan, D C; Duffy, G; Sheridan, J J; Whiting, R C; Blair, I S; McDowell, D A

    2000-04-01

    The thermotolerance of E. coli O157:H7 cells (strain 380-94) heated in pepperoni is reported. Information on the pattern of thermal inactivation of E. coli O157:H7 in pepperoni was applied in the development of heating processes designed to reduce E. coli O157:H7 numbers therein by 5 log(10) units. PMID:10742270

  12. Effects of Acid Adaptation, Product pH, and Heating on Survival of Escherichia coli O157:H7 in Pepperoni

    PubMed Central

    R. Riordan, Denise C.; Duffy, Geraldine; Sheridan, James J.; Whiting, Richard C.; Blair, Ian S.; McDowell, David A.

    2000-01-01

    The thermotolerance of E. coli O157:H7 cells (strain 380-94) heated in pepperoni is reported. Information on the pattern of thermal inactivation of E. coli O157:H7 in pepperoni was applied in the development of heating processes designed to reduce E. coli O157:H7 numbers therein by 5 log10 units. PMID:10742270

  13. Health Risk of Escherichia coli O157:H7 in Drinking Water and Meat and Meat Products and Vegetables to Diarrhoeic Confirmed and Non-Confirmed HIV/AIDS Patients

    NASA Astrophysics Data System (ADS)

    Abong`O, B. O.; Momba, M. N. B.; Rodda, N.

    The current study explored the health risk of E. coli O157:H7 to diarrhoeic confirmed and non-confirmed HIV/AIDS patients due to their exposure to presumed ingestion of water, meat products and vegetables ostensibly contaminated with E. coli O157:H7. Strains of E. coli O157:H7 were isolated by enrichment culture and on Cefixime-Telurite Sorbitol MacConkey agar. Average counts of presumptive E. coli O157 were used for dose-response assessment. Probability of infection to confirmed and non-confirmed HIV/AIDS patients was 20 and 27% from meat and meat products, 21% and 15% from vegetables and 100% due to ingestion of 1500 mL person-1 day-1 of water. Drinking water had higher probability of transmitting E. coli O157:H7 infections than meat and meat products and vegetables. Probability of E. coli O157:H7 infections were high for confirmed HIV/AIDS patients than for non-confirmed patients. Water and foods consumed by HIV/AIDS patients should be safe of any microbial contaminants, these waters and foods should as well be investigated for other enteric pathogens to establish their safety.

  14. Public Health Investigation of Two Outbreaks of Shiga Toxin-Producing Escherichia coli O157 Associated with Consumption of Watercress.

    PubMed

    Jenkins, Claire; Dallman, Timothy J; Launders, Naomi; Willis, Caroline; Byrne, Lisa; Jorgensen, Frieda; Eppinger, Mark; Adak, Goutam K; Aird, Heather; Elviss, Nicola; Grant, Kathie A; Morgan, Dilys; McLauchlin, Jim

    2015-06-15

    An increase in the number of cases of Shiga toxin-producing Escherichia coli (STEC) O157 phage type 2 (PT2) in England in September 2013 was epidemiologically linked to watercress consumption. Whole-genome sequencing (WGS) identified a phylogenetically related cluster of 22 cases (outbreak 1). The isolates comprising this cluster were not closely related to any other United Kingdom strain in the Public Health England WGS database, suggesting a possible imported source. A second outbreak of STEC O157 PT2 (outbreak 2) was identified epidemiologically following the detection of outbreak 1. Isolates associated with outbreak 2 were phylogenetically distinct from those in outbreak 1. Epidemiologically unrelated isolates on the same branch as the outbreak 2 cluster included those from human cases in England with domestically acquired infection and United Kingdom domestic cattle. Environmental sampling using PCR resulted in the isolation of STEC O157 PT2 from irrigation water at one implicated watercress farm, and WGS showed this isolate belonged to the same phylogenetic cluster as outbreak 2 isolates. Cattle were in close proximity to the watercress bed and were potentially the source of the second outbreak. Transfer of STEC from the field to the watercress bed may have occurred through wildlife entering the watercress farm or via runoff water. During this complex outbreak investigation, epidemiological studies, comprehensive testing of environmental samples, and the use of novel molecular methods proved invaluable in demonstrating that two simultaneous outbreaks of STEC O157 PT2 were both linked to the consumption of watercress but were associated with different sources of contamination. PMID:25841005

  15. Role of the Escherichia coli O157:H7 O side chain in adherence and analysis of an rfb locus.

    PubMed Central

    Bilge, S S; Vary, J C; Dowell, S F; Tarr, P I

    1996-01-01

    Shiga-toxigenic Escherichia coli strains belonging to serotype O157 are important human pathogens, but the genetic basis of expression of the O157 antigen and the role played by the lipopolysaccharide O side chain in the adherence of this organism to epithelial cells are not understood. We performed TnphoA mutagenesis on E. coli O157:H7 strain 86-24 to identify a mutant (strain F12) deficient in O-antigen expression. Nucleotide sequence analysis demonstrated that the transposon inserted within an open reading frame with significant homology to rfbE of Vibrio cholerae O1 (U. H. Stroeher, L. E. Karageorgos, R. Morona, and P. A. Manning, Proc. Natl. Acad. Sci. USA 89:2566-2570, 1992), which is postulated to encode perosamine synthetase. This open reading frame was designated rfbE(EcO157:H7). The guanine-plus-cytosine fraction (0.35) suggests that rfbE(EcO157:H7) may have originated in a species other than E. coli. rfbE(EcO157:H7) is conserved in nontoxigenic E. coli O157 strains expressing a variety of other flagellar antigens but is not found in E. coli O55:H7 strains, which are more closely related to E. coli O157:H7. Strain F12 was significantly more adherent to HeLa cells in a quantitative adherence assay than was its E. coli O157:H7 parent, but they did not differ in other phenotypes. Restoration of the expression of the O side chain by complementation of the TnphoA mutation in strain F12 by a plasmid expressing intact rfbE(EcO157:H7) reduced the adherence of the hyperadherent strain F12. We conclude that rfbE(EcO157:H7) is necessary for the expression of the O157 antigen, that acquisition of E. coli rfb genes occurred independently in E. coli O157:H7 and unrelated O157 strains, and that the O side chain of E. coli O157:H7 lipopolysaccharide interferes with the adherence of E. coli O157:H7 to epithelial cells. PMID:8890241

  16. Enumeration of Escherichia coli O157:H7 in Outbreak-Associated Beef Patties.

    PubMed

    Gill, Alexander; Huszczynski, George

    2016-07-01

    An outbreak of five cases of Escherichia coli O157 infection that occurred in Canada in 2012 was linked to frozen beef patties seasoned with garlic and peppercorn. Unopened retail packs of beef patties from the implicated production lot were recovered and analyzed to enumerate E. coli O157, other E. coli strains, and total coliforms. E. coli O157 was not recovered by direct enumeration on selective agar media. E. coli O157 in the samples was estimated at 3.1 most probable number per 140 g of beef patty, other E. coli was 11 CFU/g, and coliforms were 120 CFU/g. These results indicate that the presence of E. coli O157 in ground beef at levels below 0.1 CFU/g may cause outbreaks. However, the roles of temperature abuse, undercooking, and crosscontamination in amplifying the risk are unknown. PMID:27357049

  17. Enhanced detection sensitivity of Escherichia coli O157:H7 using surface-modified gold nanorods

    PubMed Central

    Ramasamy, Mohankandhasamy; Yi, Dong Kee; An, Seong Soo A

    2015-01-01

    Escherichia coli O157:H7 (O157) is a Gram negative and highly virulent bacteria found in food and water sources, and is a leading cause of chronic diseases worldwide. Diagnosis and prevention from the infection require simple and rapid analysis methods for the detection of pathogens, including O157. Endogenous membrane peroxidase, an enzyme present on the surface of O157, was used for the colorimetric detection of bacteria by catalytic oxidation of the peroxidase substrate. In this study, we have analyzed the impact of the synthesized bare gold nanorods (AuNRs) and silica-coated AuNRs on the growth of E. coli O157. Along with the membrane peroxidase activity of O157, other bacteria strains were analyzed. Different concentrations of nanorods were used to analyze the growth responses, enzymatic changes, and morphological alterations of bacteria by measuring optical density, 3,3′,5,5′-tetramethylbenzidine assay, flow cytometry analysis, and microscopy studies. The results revealed that O157 showed higher and continuous membrane peroxidase activity than other bacteria. Furthermore, O157 treated with bare AuNRs showed a decreased growth rate in comparison with the bacteria with surface modified AuNRs. Interestingly, silica-coated AuNRs favored the growth of bacteria and also increased membrane peroxidase activity. This result can be particularly important for the enzymatic analysis of surface treated AuNRs in various microbiological applicants. PMID:26347081

  18. Enhanced detection sensitivity of Escherichia coli O157:H7 using surface-modified gold nanorods.

    PubMed

    Ramasamy, Mohankandhasamy; Yi, Dong Kee; An, Seong Soo A

    2015-01-01

    Escherichia coli O157:H7 (O157) is a Gram negative and highly virulent bacteria found in food and water sources, and is a leading cause of chronic diseases worldwide. Diagnosis and prevention from the infection require simple and rapid analysis methods for the detection of pathogens, including O157. Endogenous membrane peroxidase, an enzyme present on the surface of O157, was used for the colorimetric detection of bacteria by catalytic oxidation of the peroxidase substrate. In this study, we have analyzed the impact of the synthesized bare gold nanorods (AuNRs) and silica-coated AuNRs on the growth of E. coli O157. Along with the membrane peroxidase activity of O157, other bacteria strains were analyzed. Different concentrations of nanorods were used to analyze the growth responses, enzymatic changes, and morphological alterations of bacteria by measuring optical density, 3,3',5,5'-tetramethylbenzidine assay, flow cytometry analysis, and microscopy studies. The results revealed that O157 showed higher and continuous membrane peroxidase activity than other bacteria. Furthermore, O157 treated with bare AuNRs showed a decreased growth rate in comparison with the bacteria with surface modified AuNRs. Interestingly, silica-coated AuNRs favored the growth of bacteria and also increased membrane peroxidase activity. This result can be particularly important for the enzymatic analysis of surface treated AuNRs in various microbiological applicants. PMID:26347081

  19. Biocontrol of Escherichia coli O157

    PubMed Central

    Boyacioglu, Olcay; Sharma, Manan; Sulakvelidze, Alexander; Goktepe, Ipek

    2013-01-01

    The effect of a bacteriophage cocktail (EcoShield™) that is specific against Escherichia coli O157:H7 was evaluated against a nalidixic acid-resistant enterohemorrhagic E. coli O157:H7 RM4407 (EHEC) strain on leafy greens stored under either (1) ambient air or (2) modified atmosphere (MA; 5% O2/35% CO2/60% N2). Pieces (~2 × 2 cm2) of leafy greens (lettuce and spinach) inoculated with 4.5 log CFU/cm2 EHEC were sprayed with EcoShield™ (6.5 log PFU/cm2). Samples were stored at 4 or 10°C for up to 15 d. On spinach, the level of EHEC declined by 2.38 and 2.49 log CFU/cm2 at 4 and 10°C, respectively, 30 min after phage application (p ≤ 0.05). EcoShield™ was also effective in reducing EHEC on the surface of green leaf lettuce stored at 4°C by 2.49 and 3.28 log units in 30 min and 2 h, respectively (p ≤ 0.05). At 4°C under atmospheric air, the phage cocktail significantly (p ≤ 0.05) lowered the EHEC counts in one day by 1.19, 3.21 and 3.25 log CFU/cm2 on spinach, green leaf and romaine lettuce, respectively compared with control (no bacteriophage) treatments. When stored under MA at 4°C, phages reduced (p ≤ 0.05) EHEC populations by 2.18, 3.50 and 3.13 log CFU/cm2, on spinach, green leaf and romaine lettuce. At 10°C, EHEC reductions under atmospheric air storage were 1.99, 3.90 and 3.99 log CFU/cm2 (p ≤ 0.05), while population reductions under MA were 3.08, 3.89 and 4.34 logs on spinach, green leaf and romaine lettuce, respectively, compared with controls (p ≤ 0.05). The results of this study showed that bacteriophages were effective in reducing the levels of E. coli O157:H7 on fresh leafy produce, and that the reduction was further improved when produce was stored under the MA conditions. PMID:23819107

  20. Efficacy of levulinic acid-sodium dodecyl sulfate against Encephalitozoon intestinalis, Escherichia coli O157:H7, and Cryptosporidium parvum.

    PubMed

    Ortega, Ynes R; Torres, Maria P; Tatum, Jessica M

    2011-01-01

    Foodborne parasites are characterized as being highly resistant to sanitizers used by the food industry. In 2009, a study reported the effectiveness of levulinic acid in combination with sodium dodecyl sulfate (SDS) in killing foodborne bacteria. Because of their innocuous properties, we studied the effects of levulinic acid and SDS at various concentrations appropriate for use in foods, on the viability of Cryptosporidium parvum and Encephalitozoon intestinalis. The viability of Cryptosporidium and E. intestinalis was determined by in vitro cultivation using the HCT-8 and RK-13 cell lines, respectively. Two Escherichia coli O157:H7 isolates were also used in the present study: strain 932 (a human isolate from a 1992 Oregon meat outbreak) and strain E 0018 (isolated from calf feces). Different concentrations and combinations of levulinic acid and SDS were tested for their ability to reduce infectivity of C. parvum oocysts (10(5)), E. intestinalis spores (10(6)), and E. coli O157:H7 (10(7)/ml) when in suspension. Microsporidian spores were treated for 30 and 60 min at 20 ± 2°C. None of the combinations of levulinic acid and SDS were effective at inactivating the spores or oocysts. When Cryptosporidium oocysts were treated with higher concentrations (3% levulinic acid-2% SDS and 2% levulinic acid-1% SDS) for 30, 60, and 120 min, viability was unaffected. E. coli O157:H7, used as a control, was highly sensitive to the various concentrations and exposure times tested. SDS and levulinic acid alone had very limited effect on E. coli O157:H7 viability, but in combination they were highly effective at 30 and 60 min of incubation. In conclusion, Cryptosporidium and microsporidia are not inactivated when treated for various periods of time with 2% levulinic acid-1% SDS or 3% levulinic acid-2% SDS at 20°C, suggesting that this novel sanitizer cannot be used to eliminate parasitic contaminants in foods. PMID:21219777

  1. Shiga Toxin-Producing Escherichia coli in Finland from 1990 through 1997: Prevalence and Characteristics of Isolates

    PubMed Central

    Keskimäki, Markku; Saari, Marjut; Heiskanen, Tarja; Siitonen, Anja

    1998-01-01

    During the past 10 years Shiga toxin-producing Escherichia coli (STEC) has emerged as one of the most important causes of food-borne infections in industrialized countries. In Finland, with a population of 5.1 million, however, only four STEC O157:H7 infections were identified from 1990 through 1995; the occurrence of non-O157 STEC infections was unknown. In 1996, we established a national prospective study to determine the prevalence of STEC serotypes in feces of Finns with bloody diarrhea. During this enhanced 1-year study period eight sporadic cases of STEC infection were found; of them, only two were indigenously acquired O157:H7 infections. In 1997, O157 infections increased dramatically, with O157 strains causing 51 of all 61 STEC infections. Altogether 14 non-O157:H7 STEC strains were found in Finland in the 1990s: O26:H11 (four strains), O26:HNM (HNM indicates nonmotile), O2:H29, O91:H21, O91:H40, O101:HNM, O107:H27, O157:HNM, O165:H25, OX3:H21, and Rough:H49. All O157:H7 and O26:H11 isolates produced enterohemolysin, but seven of the other STEC strains did not. Most (n = 63) of the 71 STEC strains isolated carried the stx2 gene only, five carried the stx1 gene only, and three carried both genes. The eaeA gene was detected in all other isolates except five non-O157 strains. There were seven distinct pulsed-field gel electrophoresis (PFGE) genotypes among 57 O157 strains and three distinct PFGE types among four O26:H11 strains. The main PFGE type was found among 65% of all O157 isolates. PMID:9817888

  2. Comparison of eight different agars for the recovery of clinically relevant non-O157 Shiga toxin-producing Escherichia coli from baby spinach, cilantro, alfalfa sprouts and raw milk.

    PubMed

    Kase, Julie A; Maounounen-Laasri, Anna; Son, Insook; Lin, Andrew; Hammack, Thomas S

    2015-04-01

    The FDA Bacteriological Analytical Manual (BAM) Chapter 4a recommends several agars for isolating non-O157 Shiga toxin-producing Escherichia coli (STEC); not all have been thoroughly tested for recovering STECs from food. Using E. coli strains representing ten clinically relevant O serogroups (O26, O45, O91, O103, O104, O111, O113, O121, O128, O145) in artificially-contaminated fresh produce--bagged baby spinach, alfalfa sprouts, cilantro, and raw milk--we evaluated the performance of 8 different agars. Performance was highly dependent upon strain used and the presence of inhibitors, but not necessarily dependent on food matrix. Tellurite resistant-negative strains, O91:-, O103:H6, O104:H21, O113:H21, and O128, grew poorly on CHROMagar STEC, Rainbow agar O157, and a modified Rainbow O157 (mRB) agar. Although adding washed sheep's blood to CHROMagar STEC and mRB agars improved overall performance; however, this also reversed the inhibition of non-target bacteria provided by original formulations. Variable colony coloration made selecting colonies from Rainbow agar O157 and mRB agars difficult. Study results support a strategy using inclusive agars (e.g. L-EMB, SHIBAM) in combination with selective agars (R & F E. coli O157:H7, CHROMagar STEC) to allow for recovery of the most STECs while increasing the probability of recovering STEC in high bacterial count matrices. PMID:25475297

  3. Whole Genome Sequencing for Public Health Surveillance of Shiga Toxin-Producing Escherichia coli Other than Serogroup O157.

    PubMed

    Chattaway, Marie A; Dallman, Timothy J; Gentle, Amy; Wright, Michael J; Long, Sophie E; Ashton, Philip M; Perry, Neil T; Jenkins, Claire

    2016-01-01

    Shiga toxin-producing Escherichia coli (STEC) are considered to be a significant threat to public health due to the severity of gastrointestinal symptoms associated with human infection. In England STEC O157 is the most commonly detected STEC serogroup, however, the implementation of PCR at local hospital laboratories has resulted in an increase in the detection of non-O157 STEC. The aim of this study was to evaluate the use of whole genome sequencing (WGS) for routine public health surveillance of non-O157 STEC by comparing this approach to phenotypic serotyping and PCR for subtyping the stx-encoding genes. Of the 102 isolates where phenotypic and genotypic serotyping could be compared, 98 gave fully concordant results. The most common non-O157 STEC serogroups detected were O146 (22) and O26 (18). All but one of the 38 isolates that could not be phenotypically serotyped (designated O unidentifiable or O rough) were serotyped using the WGS data. Of the 73 isolates where a flagella type was available by traditional phenotypic typing, all results matched the H-type derived from the WGS data. Of the 140 sequenced non-O157 isolates, 52 (37.1%) harboured stx1 only, 42 (30.0%) had stx2 only, 46 (32.9%) carried stx1 and stx2. Of these, stx subtyping PCR results were available for 131 isolates and 121 of these had concordant results with the stx subtype derived from the WGS data. Of the 10 discordant results, non-specific primer binding during PCR amplification, due to the similarity of the stx2 subtype gene sequences was the most likely cause. The results of this study showed WGS provided a reliable and robust one-step process for characterization of STEC. Deriving the full serotype from WGS data in real time has enabled us to report a higher level of strain discrimination while stx subtyping provides data on the pathogenic potential of each isolate, enabling us to predict clinical outcome of each case and to monitor the emergence of hyper-virulent strains. PMID:26973632

  4. Whole Genome Sequencing for Public Health Surveillance of Shiga Toxin-Producing Escherichia coli Other than Serogroup O157

    PubMed Central

    Chattaway, Marie A.; Dallman, Timothy J.; Gentle, Amy; Wright, Michael J.; Long, Sophie E.; Ashton, Philip M.; Perry, Neil T.; Jenkins, Claire

    2016-01-01

    Shiga toxin-producing Escherichia coli (STEC) are considered to be a significant threat to public health due to the severity of gastrointestinal symptoms associated with human infection. In England STEC O157 is the most commonly detected STEC serogroup, however, the implementation of PCR at local hospital laboratories has resulted in an increase in the detection of non-O157 STEC. The aim of this study was to evaluate the use of whole genome sequencing (WGS) for routine public health surveillance of non-O157 STEC by comparing this approach to phenotypic serotyping and PCR for subtyping the stx-encoding genes. Of the 102 isolates where phenotypic and genotypic serotyping could be compared, 98 gave fully concordant results. The most common non-O157 STEC serogroups detected were O146 (22) and O26 (18). All but one of the 38 isolates that could not be phenotypically serotyped (designated O unidentifiable or O rough) were serotyped using the WGS data. Of the 73 isolates where a flagella type was available by traditional phenotypic typing, all results matched the H-type derived from the WGS data. Of the 140 sequenced non-O157 isolates, 52 (37.1%) harboured stx1 only, 42 (30.0%) had stx2 only, 46 (32.9%) carried stx1 and stx2. Of these, stx subtyping PCR results were available for 131 isolates and 121 of these had concordant results with the stx subtype derived from the WGS data. Of the 10 discordant results, non-specific primer binding during PCR amplification, due to the similarity of the stx2 subtype gene sequences was the most likely cause. The results of this study showed WGS provided a reliable and robust one-step process for characterization of STEC. Deriving the full serotype from WGS data in real time has enabled us to report a higher level of strain discrimination while stx subtyping provides data on the pathogenic potential of each isolate, enabling us to predict clinical outcome of each case and to monitor the emergence of hyper-virulent strains. PMID:26973632

  5. Experimental and Field Studies of Escherichia coli O157:H7 in White-Tailed Deer

    PubMed Central

    Fischer, John R.; Zhao, Tong; Doyle, Michael P.; Goldberg, Martin R.; Brown, Cathy A.; Sewell, Christopher T.; Kavanaugh, Darrell M.; Bauman, Christopher D.

    2001-01-01

    Studies were conducted to evaluate fecal shedding of Escherichia coli O157:H7 in a small group of inoculated deer, determine the prevalence of the bacterium in free-ranging white-tailed deer, and elucidate relationships between E. coli O157:H7 in wild deer and domestic cattle at the same site. Six young, white-tailed deer were orally administered 108 CFU of E. coli O157:H7. Inoculated deer were shedding E. coli O157:H7 by 1 day postinoculation (DPI) and continued to shed decreasing numbers of the bacteria throughout the 26-day trial. Horizontal transmission to an uninoculated deer was demonstrated. Although E. coli O157:H7 bacteria were recovered from the gastrointestinal tracts of deer necropsied from 4 to 26 DPI, attaching and effacing lesions were not apparent in any deer. Results are similar to those of inoculation studies in calves and sheep. In field studies, E. coli O157 was not detected in 310 fresh deer fecal samples collected from the ground. It was detected in feces, but not in meat, from 3 of 469 free-ranging deer in 1997. In 1998, E. coli O157 was not detected in 140 deer at the single positive site found in 1997; however, it was recovered from 13 of 305 dairy and beef cattle at the same location. Isolates of E. coli O157:H7 from deer and cattle at this site differed with respect to pulsed-field gel electrophoresis patterns and genes encoding Shiga toxins. The low overall prevalence of E. coli O157:H7 and the identification of only one site with positive deer suggest that wild deer are not a major reservoir of E. coli O157:H7 in the southeastern United States. However, there may be individual locations where deer sporadically harbor the bacterium, and venison should be handled with the same precautions recommended for beef, pork, and poultry. PMID:11229913

  6. Detection, Virulence Gene Assessment and Antibiotic Resistance Pattern of O157 Enterohemorrhagic Escherichia coli in Tabriz, Iran

    PubMed Central

    Akhi, Mohammad Taghi; Ostadgavahi, Ali Toloue; Ghotaslou, Reza; Asgharzadeh, Mohammad; Pirzadeh, Tahereh; Sorayaei Sowmesarayi, Vida; Memar, Mohammad Yousef

    2015-01-01

    Background: Shiga toxin-producing Escherichia coli (STEC) is a food-borne pathogen and infection with this organism causes illnesses such as bloody diarrhea, hemorrhagic colitis and hemolytic-uremic syndrome. Objectives: Considering the lack of any information about the prevalence rate and the antibiotic resistance pattern of O157:H7 serotype in Tabriz, finding answers to the above mentioned subjects was among the goals of this study. Materials and Methods: Two hundred E. coli strains from diarrheal or non-diarrheal stools of outpatients and hospitalized cases in Tabriz Imam Reza hospital were isolated between September and December 2014 using MacConkey agar and standard biochemical tests and then cultured on sorbitol MacConkey agar. The sorbitol-negative isolates were confirmed as the O157 serotype using O157 antisera. A multiplex polymerase chain reaction (PCR) method was used for the detection of stx-1, stx-2, eae, and mdh genes and the antibiotic resistance pattern of these isolates was determined using Kirby-Bauer method and clinical and laboratory standards institute (CLSI) standards. Results: Of the isolates 11 (5.5%) were sorbitol-negative, which were later analyzed by multiplex PCR and the results revealed that 2 (18.18%) isolates contained the stx-1 gene, 10 (90.91%) contained the stx-2 gene, and 5 (45.45%) contained the eae gene. The stx-2 and eae genes were the most commonly encountered virulence factors. All or most of the isolates were susceptible to ceftazidime (100%), gentamicin (100%), ciprofloxacin (100%), nalidixic acid (90.9%), trimetoprim sulfamethoxazole (90.9%), chloramphenicol (90.9%), ampicillin (81.8%), and cephalothin (72.7%). On the contrary, moderate susceptibility of the isolates to doxycycline (54.5%) was observed. Conclusions: Due to the low frequency of STEC O157 and the high susceptibility rates of the isolates to the tested antibiotics in this study, STEC O157 has not become a major problem in Tabriz yet, but comprehensive

  7. Shiga-toxigenic Escherichia coli O157 in Agricultural Fair Livestock, United States

    PubMed Central

    Wittum, Thomas E.; Dunn, John R.; Bono, James L.; Durso, Lisa M.

    2006-01-01

    Agricultural fairs exhibiting livestock are increasingly implicated in human Shiga-toxigenic Escherichia coli O157:H7 (STEC O157:H7) outbreaks. To estimate livestock STEC O157:H7 prevalence at US fairs, we collected 2,919 fecal specimens at 29 county fairs in 2 states and at 3 state fairs in 2002. Fly pools were also collected. STEC O157:H7 was isolated from livestock at 31 (96.9%) of 32 fairs, including 11.4% of 1,407 cattle, 1.2% of 1,102 swine, 3.6% of 364 sheep and goats, and 5.2% of 154 fly pools. Cattle, swine, and flies at some fairs shared indistinguishable STEC O157:H7 isolate subtypes. In 2003, a total of 689 ambient environmental samples were collected at 20 fairgrounds 10–11 months after 2002 livestock sampling while fairgrounds were livestock-free. Four beef barn environmental samples at 3 fairgrounds yielded STEC O157:H7. These data suggest that STEC O157 is common and transmissible among livestock displayed at agricultural fairs and persists in the environment after the fair. PMID:16704838

  8. Molecular characterization of Escherichia coli O157:H7 hide contamination routes: feedlot to harvest.

    PubMed

    Childs, K D; Simpson, C A; Warren-Serna, W; Bellenger, G; Centrella, B; Bowling, R A; Ruby, J; Stefanek, J; Vote, D J; Choat, T; Scanga, J A; Sofos, J N; Smith, G C; Belk, K E

    2006-06-01

    This study was conducted to identify the origin of Escherichia coli O157:H7 contamination on steer hides at the time of harvest. Samples were collected from the feedlot, transport trailers, and packing plant holding pens and from the colons and hides of feedlot steers. A total of 50 hide samples were positive for E. coli O157:H7 in two geographical locations: the Midwest (25 positive hides) and Southwest (25 positive hides). Hide samples were screened, and the presence of E. coli O157: H7 was confirmed. E. coli O157:H7 isolates were fingerprinted by pulsed-field gel electrophoresis and subjected to multiplex PCR procedures for amplification of E. coli O157:H7 genes stx1, stx2, eaeA, fliC, rfbEO157, and hlyA. Feedlot water trough, pen floor, feed bunk, loading chute, truck trailer side wall and floor, packing plant holding pen floor and side rail, and packing plant cattle drinking water samples were positive for E. coli O157:H7. Pulsed-field gel electrophoresis banding patterns were analyzed after classifying isolates according to the marker genes present and according to packing plant. In this study, hide samples positive for E. coli O157:H7 were traced to other E. coli O157:H7-positive hide, colon, feedlot pen floor fecal, packing plant holding pen drinking water, and transport trailer side wall samples. Links were found between packing plant side rails, feedlot loading chutes, and feedlot pens and between truck trailer, different feedlots, and colons of multiple cattle. This study is the first in which genotypic matches have been made between E. coli O157:H7 isolates obtained from transport trailer side walls and those from cattle hide samples within the packing plant. PMID:16786841

  9. Application of Bacteriophages To Control Intestinal Escherichia coli O157:H7 Levels in Ruminants

    PubMed Central

    Sheng, Haiqing; Knecht, Hannah J.; Kudva, Indira T.; Hovde, Carolyn J.

    2006-01-01

    A previously characterized O157-specific lytic bacteriophage KH1 and a newly isolated phage designated SH1 were tested, alone or in combination, for reducing intestinal Escherichia coli O157:H7 in animals. Oral treatment with phage KH1 did not reduce the intestinal E. coli O157:H7 in sheep. Phage SH1 formed clear and relatively larger plaques on lawns of all 12 E. coli O157:H7 isolates tested and had a broader host range than phage KH1, lysing O55:H6 and 18 of 120 non-O157 E. coli isolates tested. In vitro, mucin or bovine mucus did not inhibit bacterial lysis by phage SH1 or KH1. A phage treatment protocol was optimized using a mouse model of E. coli O157:H7 intestinal carriage. Oral treatment with SH1 or a mixture of SH1 and KH1 at phage/bacterium ratios ≥102 terminated the presence of fecal E. coli O157:H7 within 2 to 6 days after phage treatment. Untreated control mice remained culture positive for >10 days. To optimize bacterial carriage and phage delivery in cattle, E. coli O157:H7 was applied rectally to Holstein steers 7 days before the administration of 1010 PFU SH1 and KH1. Phages were applied directly to the rectoanal junction mucosa at phage/bacterium ratios calculated to be ≥102. In addition, phages were maintained at 106 PFU/ml in the drinking water of the phage treatment group. This phage therapy reduced the average number of E. coli O157:H7 CFU among phage-treated steers compared to control steers (P < 0.05); however, it did not eliminate the bacteria from the majority of steers. PMID:16885287

  10. Isolation of atypical enteropathogenic and shiga toxin encoding Escherichia coli strains from poultry in Tehran, Iran

    PubMed Central

    Doregiraee, Fatemeh; Alebouyeh, Masoud; Nayeri Fasaei, Bahar; Charkhkar, Saeed; Tajedin, Elahe; Zali, Mohammad Reza

    2016-01-01

    Aim: The purpose of this study was to investigate the prevalence of enteropathogenic Escherichia coli (EPEC) and shiga toxin producing E. coli (STEC) strains in healthy broilers in Iran. Background: STEC and EPEC strains as diarrheagenic E. coli are among the most prevalent causative agents in acute diarrhea. Domestic animals, mainly cattle and sheep, have been implicated as the principal reservoirs of these pathotypes; however their prevalence among the broilers is varied among different countries. Patients and methods: A total of 500 cloacal swab samples from broilers of five different poultry houses (A-E) were collected to investigate the presence of stx1, stx2, hly, eae, and bfp virulence genes among the E. coli isolates by polymerase chain reaction. The shiga toxin encoding strains were evaluated serologically to detect their interaction with a commercial antiserum against O157 antigen. Results: Out of the 500 collected samples, 444 E. coli strains were isolated. Three strains (0.67%) presented at least one of the studied virulence genes (stx2, hly and eae), two strains were identified as STEC (stx2+, O157:nonH7) and one as an atypical EPEC strains (eae+ bfp-). Conclusion: The study established the presence of STEC and atypical EPEC in healthy broilers in Iran. Poultry might serve as vectors for transmission of pathogenic E. coli to human populations. PMID:26744615

  11. Defects in polynucleotide phosphorylase impairs virulence in Escherichia coli O157:H7.

    PubMed

    Hu, Jia; Zhu, Mei-Jun

    2015-01-01

    Polynucleotide phosphorylase (PNPase) is reported to regulate virulence in Salmonella, Yersinia sp. and Campylobacter jejuni, yet its role in Escherichia coli O157:H7 has not been investigated. To gain insights into its roles in E. coli O157:H7 virulence, pnp deletion mutants were generated and the major virulence factors were compared to their parental wild type strains. Deletion of pnp in E. coli O157:H7 dramatically decreased stx2 mRNA expression and Stx2 protein production, and impaired lambdoid prophage activation in E. coli O157:H7. Quantitative PCR further confirmed that the Stx2 phage lytic growth was repressed by pnp deletion. Consistent with reduced Stx2 production and Stx2 phage activation, the transcriptional levels of genes involved in phage lysis and replication were down-regulated. In addition, disruption of pnp in E. coli O157:H7 decreased its adhesion to intestinal epithelial cells as well as cattle colonic explant tissues. On the other hand, PNPase inactivation in E. coli O157:H7 enhanced Tir protein content and the transcription of type three secretion system components, including genes encoding intimin, Tir, and EspB as well as locus of enterocyte and effacement positive regulator, Ler. Collectively, data indicate that PNPase has pleiotropic effects on the virulence of E. coli O157:H7. PMID:26347717

  12. Defects in polynucleotide phosphorylase impairs virulence in Escherichia coli O157:H7

    PubMed Central

    Hu, Jia; Zhu, Mei-Jun

    2015-01-01

    Polynucleotide phosphorylase (PNPase) is reported to regulate virulence in Salmonella, Yersinia sp. and Campylobacter jejuni, yet its role in Escherichia coli O157:H7 has not been investigated. To gain insights into its roles in E. coli O157:H7 virulence, pnp deletion mutants were generated and the major virulence factors were compared to their parental wild type strains. Deletion of pnp in E. coli O157:H7 dramatically decreased stx2 mRNA expression and Stx2 protein production, and impaired lambdoid prophage activation in E. coli O157:H7. Quantitative PCR further confirmed that the Stx2 phage lytic growth was repressed by pnp deletion. Consistent with reduced Stx2 production and Stx2 phage activation, the transcriptional levels of genes involved in phage lysis and replication were down-regulated. In addition, disruption of pnp in E. coli O157:H7 decreased its adhesion to intestinal epithelial cells as well as cattle colonic explant tissues. On the other hand, PNPase inactivation in E. coli O157:H7 enhanced Tir protein content and the transcription of type three secretion system components, including genes encoding intimin, Tir, and EspB as well as locus of enterocyte and effacement positive regulator, Ler. Collectively, data indicate that PNPase has pleiotropic effects on the virulence of E. coli O157:H7. PMID:26347717

  13. Non-O157 Shiga toxin-producing Escherichia coli: prevalence associated with meat animals and controlling interventions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This paper reviews the current state of knowledge of non-O157 STEC in products of meat animals. There is a wide range in pathogenicity of STEC strains. Potential regulation in meat products is currently focused on the group of six O groups the CDC indicates accounts of 71% of non-O157 STEC illness...

  14. KatP contributes to OxyR-regulated hydrogen peroxide resistance in Escherichia coli serotype O157:H7

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Escherichia coli K12 defends against peroxide mediated oxidative damage using two catalases, hydroperoxidase I (katG) and hydroperoxidase II (katE) and the peroxiredoxin, alkyl hydroperoxide reductase (ahpC). In E. coli O157:H7 strain ATCC 43895 (EDL933), plasmid pO157 encodes for an additional cata...

  15. Effects of the ergot alkaloids dihydroergotamine, ergonovine, and ergotamine on growth of Escherichia coli O157:H7 in vitro

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A series of experiments were conducted to evaluate the effects of ergot alkaloids (dihydroergotamine, ergonovine, and ergotamine) on E. coli O157:H7 in both pure and mixed ruminal fluid culture. Alkaloids were added to solutions of E. coli O157:H7 strains 933 (pure and ruminal cultures) and 6058 (r...

  16. Reduction of Escherichia coli O157:H7 and Salmonella on fresh-cut produce by caprylic acid

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Caprylic acid (CA) was evaluated for reducing E. coli O157: H7 and Salmonella on spinach and lettuce leaves. Spinach, Romaine lettuce and Iceberg lettuce leaves were inoculated with a cocktail of five E. coli O157: H7 or Salmonella strains, air dried for 30 min, and then dipped in caprylic acid (10,...

  17. Enhancing the thermal destruction of Escherichia coli O157:H7 in ground beef patties by trans-cinnamaldehyde

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study investigated the effect of trans-cinnamaldehyde, an active ingredient in cinnamon, for inactivating E. coli O157:H7 in undercooked ground beef patties. A five-strain mixture of E. coli O157:H7 was inoculated into ground beef (90% lean and 10% fat) at approximately 7.0 log CFU/g, followed ...

  18. Effects of ractopamine HCl on Escherichia coli O157:H7 and Salmonella in vitro and on intestinal populations and fecal shedding in experimentally infected sheep and pigs.

    PubMed

    Edrington, Thomas S; Callaway, Todd R; Smith, David J; Genovese, Ken J; Anderson, Robin C; Nisbet, David J

    2006-07-01

    The effects of the beta-agonist ractopamine, approved for use in finishing swine and cattle to improve carcass quality and performance, were examined on two important foodborne pathogens, Escherichia coli O157:H7 and Salmonella. Ractopamine, administered to sheep before and after oral inoculation with E. coli O157:H7, increased (P < 0.01) fecal shedding and tended to increase (P = 0.08) cecal populations of the challenge strain. Pigs receiving ractopamine in the diet and then experimentally infected with Salmonella Typhimurium, had decreased (P < 0.05) fecal shedding and fewer (P = 0.05) liver samples positive for the challenge strain of Salmonella. Pure cultures of E. coli O157:H7 (used in the present sheep study), E. coli O157:H19 (isolated from pigs with postweaning diarrhea), Salmonella Typhimurium (used in the present pig study), and Salmonella Choleraesuis were incubated with varying concentrations of ractopamine to determine if ractopamine has a direct effect on bacterial growth. No differences in growth rate were observed for either strain of E. coli or for Salmonella Typhimurium when incubated with increasing concentrations of ractopamine. The growth rate for Salmonella Choleraesuis was increased with the addition of 2.0 mug ractopamine/ml compared with the other concentrations examined. Collectively, these results indicate that ractopamine may influence gut populations and fecal shedding of E. coli O157:H7 and Salmonella. Because ractopamine is currently approved to be fed to finishing cattle and swine immediately before slaughter, any potential for decreasing foodborne pathogens has exciting food safety implications. PMID:16775793

  19. Infections with verotoxin-producing escherichia coli O157:H7 and other serotypes, including the outbreak strain O104:H4.

    PubMed

    Buvens, G; Piérard, D

    2012-01-01

    Through the acquisition of mobile genetic elements, the normally harmless commensal Escherichia coli evolved into a highly adapted human pathogen. Pathogenic strains of E. coli are associated with urinary tract infections, sepsis/meningitis, and diarrhoea. At least six different diarrhoeagenic E. coli pathotypes have emerged during the past three decades as human pathogens of public health importance worldwide. In this review, we focus on the clinical features, pathogenic mechanisms, and diagnostic strategies of verotoxin-producing E. coli (VTEC) that are associated with sporadic cases and epidemics of gastrointestinal disease throughout the world. Recently, an E. coli strain of serotype O104:H4 combining verotoxin production with virulence factors of another pathotype, the enteroaggregative E. coli (EAEC), emerged as the cause of a severe outbreak in Europe. PMID:22480032

  20. A Brief Overview of Escherichia coli O157:H7 and Its Plasmid O157

    PubMed Central

    Lim, Ji Youn; Yoon, Jang W.; Hovde, Carolyn J.

    2013-01-01

    Enterohemorrhagic Escherichia coli O157:H7 is a major foodborne pathogen causing severe disease in humans worldwide. Healthy cattle are a reservoir of E. coli O157:H7, and bovine food products and fresh produce contaminated with bovine waste are the most common sources for disease outbreaks in the United States. E. coli O157:H7 also survives well in the environment. The abilities to cause human disease, colonize the bovine gastrointestinal tract, and survive in the environment require that E. coli O157:H7 adapt to a wide variety of conditions. Three major virulence factors of E. coli O157:H7 have been identified including Shiga toxins, products of the pathogenicity island called the locus of enterocyte effacement, and products of the F-like plasmid pO157. Among these virulence factors, the role of pO157 is least understood. This review provides a board overview of E. coli O157:H7 with an emphasis on pO157. PMID:20134227

  1. The Escherichia coli O157:H7 bovine rumen fluid proteome reflects adaptive bacterial responses

    PubMed Central

    2014-01-01

    Background To obtain insights into Escherichia coli O157:H7 (O157) survival mechanisms in the bovine rumen, we defined the growth characteristics and proteome of O157 cultured in rumen fluid (RF; pH 6.0-7.2 and low volatile fatty acid content) obtained from rumen-fistulated cattle fed low protein content “maintenance diet” under diverse in vitro conditions. Results Bottom-up proteomics (LC-MS/MS) of whole cell-lysates of O157 cultured under anaerobic conditions in filter-sterilized RF (fRF; devoid of normal ruminal microbiota) and nutrient-depleted and filtered RF (dRF) resulted in an anaerobic O157 fRF-and dRF-proteome comprising 35 proteins functionally associated with cell structure, motility, transport, metabolism and regulation, but interestingly, not with O157 virulence. Shotgun proteomics-based analysis using isobaric tags for relative and absolute quantitation used to further study differential protein expression in unfiltered RF (uRF; RF containing normal rumen microbial flora) complemented these results. Conclusions Our results indicate that in the rumen, the first anatomical compartment encountered by this human pathogen within the cattle gastrointestinal tract (GIT), O157 initiates a program of specific gene expression that enables it to adapt to the in vivo environment, and successfully transit to its colonization sites in the bovine GIT. Further experiments in vitro using uRF from animals fed different diets and with additional O157 strains, and in vivo using rumen-fistulated cattle will provide a comprehensive understanding of the adaptive mechanisms involved, and help direct evolution of novel modalities for blocking O157 infection of cattle. PMID:24559513

  2. Oral neomycin therapy reduces shiga-toxigenic E. coli (STEC) O157 fecal shedding in naturally-infected beef cattle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Reducing the infection prevalence in livestock of zoonotic food-borne enteric pathogens such as STEC O157 has been largely intractable to date in spite of an intense research effort over the past decade. Based on in vitro antibiotic resistance data generated from diverse bovine STEC O157 isolates su...

  3. Synergistic interaction in dual-species biofilms formation by Escherichia coli O157:H7 and Ralstonia spp

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Introduction: Ralstonia spp., a heterotrophic bacterium that are isolated from produce processing environments as part of the native microflora, have strong potentials for formaing biofilms on various surfaces. When co-cultured, Escherichia coli O157:H7 (EcO157) and Ralstonia spp. displayed a synerg...

  4. Dual-species biofilms formation by Escherichia coli O157:H7 and environmental bacteria isolated from fresh-cut processing plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biofilm formation is a mechanism adapted by many microorganisms that enhances the survival in stressful environments. In food processing facilities, bacterial strains with strong biofilm forming capacities are more likely to survive the daily cleaning and disinfection. Foodborne bacterial pathogens,...

  5. Shiga toxin-producing Escherichia coli strains isolated from dairy products - Genetic diversity and virulence gene profiles.

    PubMed

    Douëllou, T; Delannoy, S; Ganet, S; Mariani-Kurkdjian, P; Fach, P; Loukiadis, E; Montel, Mc; Thevenot-Sergentet, D

    2016-09-01

    Shiga toxin-producing Escherichia coli (STEC) are widely recognized as pathogens causing food borne disease. Here we evaluate the genetic diversity of 197 strains, mainly STEC, from serotypes O157:H7, O26:H11, O103:H2, O111:H8 and O145:28 and compared strains recovered in dairy products against strains from human, meat and environment cases. For this purpose, we characterized a set of reference-collection STEC isolates from dairy products by PFGE DNA fingerprinting and a subset of these by virulence-gene profiling. PFGE profiles of restricted STEC total DNA showed high genomic variability (0.9976 on Simpson's discriminatory index), enabling all dairy isolates to be differentiated. High-throughput real-time PCR screening of STEC virulence genes were applied on the O157:H7 and O26:H11 STEC isolates from dairy products and human cases. The virulence gene profiles of dairy and human STEC strains were similar. Nevertheless, frequency-wise, stx1 was more prevalent among dairy O26:H11 isolates than in human cases ones (87% vs. 44%) while stx2 was more prevalent among O26:H11 human isolates (23% vs. 81%). For O157:H7 isolates, stx1 (0% vs. 39%), nleF (40% vs 94%) and Z6065 (40% vs 100%) were more prevalent among human than dairy strains. Our data point to differences between human and dairy strains but these differences were not sufficient to associate PFGE and virulence gene profiles to a putative lower pathogenicity of dairy strains based on their lower incidence in disease. Further comparison of whole-genome expression and virulence gene profiles should be investigated in cheese and intestinal tract samples. PMID:27257743

  6. Antimicrobial activity of commercial citrus-based natural extracts against Escherichia coli O157:H7 isolates and mutant strains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Due to increasing concerns about the development of antimicrobial resistance amongst pathogenic bacteria, alternative strategies have been sought that do not use antibiotics to reduce pathogenic bacteria from foods and patients. A natural compound that has potent antimicrobial properties is citrus ...

  7. Genotypic analyses of shiga toxin-producing Escherichia coli O157 and non-O157 recovered from feces of domestic animals on rural farms in Mexico.

    PubMed

    Amézquita-López, Bianca A; Quiñones, Beatriz; Cooley, Michael B; León-Félix, Josefina; Castro-del Campo, Nohelia; Mandrell, Robert E; Jiménez, Maribel; Chaidez, Cristóbal

    2012-01-01

    Shiga toxin-producing Escherichia coli (STEC) are zoonotic enteric pathogens associated with human gastroenteritis worldwide. Cattle and small ruminants are important animal reservoirs of STEC. The present study investigated animal reservoirs for STEC in small rural farms in the Culiacan Valley, an important agricultural region located in Northwest Mexico. A total of 240 fecal samples from domestic animals were collected from five sampling sites in the Culiacan Valley and were subjected to an enrichment protocol followed by either direct plating or immunomagnetic separation before plating on selective media. Serotype O157:H7 isolates with the virulence genes stx2, eae, and ehxA were identified in 40% (26/65) of the recovered isolates from cattle, sheep and chicken feces. Pulse-field gel electrophoresis (PFGE) analysis grouped most O157:H7 isolates into two clusters with 98.6% homology. The use of multiple-locus variable-number tandem repeat analysis (MLVA) differentiated isolates that were indistinguishable by PFGE. Analysis of the allelic diversity of MLVA loci suggested that the O157:H7 isolates from this region were highly related. In contrast to O157:H7 isolates, a greater genotypic diversity was observed in the non-O157 isolates, resulting in 23 PFGE types and 14 MLVA types. The relevant non-O157 serotypes O8:H19, O75:H8, O111:H8 and O146:H21 represented 35.4% (23/65) of the recovered isolates. In particular, 18.5% (12/65) of all the isolates were serotype O75:H8, which was the most variable serotype by both PFGE and MLVA. The non-O157 isolates were predominantly recovered from sheep and were identified to harbor either one or two stx genes. Most non-O157 isolates were ehxA-positive (86.5%, 32/37) but only 10.8% (4/37) harbored eae. These findings indicate that zoonotic STEC with genotypes associated with human illness are present in animals on small farms within rural communities in the Culiacan Valley and emphasize the need for the development of control

  8. Prevalence and characterization of verotocytoxin producing Escherichia coli O157 from diarrhoea patients in Morogoro, Tanzania.

    PubMed

    Rajii, M A; Minga, U M; Machang'u, R S

    2008-07-01

    Escherichia coli O157:H7 is an important agent of haemorrhagic colitis and haemolytic uraemic syndrome in children less than five years old and elderly people. The objective of this study was to investigate the prevalence of verotocytoxin producing E. coli 0157 (VTEC O157) among human patients with diarrhoea in Morogoro, Tanzania. Faecal samples originating from 275 human patients with diarrhoea were screened for presence of E. coli O157:H7. A total of 96 E. coli isolate were identified. Of these, 10 isolates were grouped into sorbitol non-fermenting and glucuronide negative and 49 isolates were sorbitol positive and glucuronide positive. The remaining 37 were sorbitol negative and glucuronide positive. Using the polymerase chain reaction techniques, a total often verotocytocin producing E. coli isolated in this study were used. The overall two (15%) and one (7%) of the isolated of E. coli possessed both attaching and effacing (eae A) and enterohemolysin (ehly) A genes respectively. Other enterobacterial agents including Pseudomonas spp, Proteus spp and coliforms were also isolated. The VTEC O157 isolates were 100% resistant to oxytetracycline, chloramphenicol, streptomycin, and amoxyclav. In conclusion, the isolation of diarrhoeaogenic E. coli O157:H7 in this region suggests that the pathogen is an important aetiology of acute gastroenteritis in Tanzania. There is therefore, need to improve sewage and refuse disposal system, the provision of safe potable water, sanitation, personal hygiene and health education in order to reduce infection with this and other enteric pathogens. PMID:19024340

  9. Lytic bacteriophages reduce Escherichia coli O157

    PubMed Central

    Ferguson, Sean; Roberts, Cheryl; Handy, Eric; Sharma, Manan

    2013-01-01

    The role of lytic bacteriophages in preventing cross contamination of produce has not been evaluated. A cocktail of three lytic phages specific for E. coli O157:H7 (EcoShield™) or a control (phosphate buffered saline, PBS) was applied to lettuce by either; (1) immersion of lettuce in 500 ml of EcoShield™ 8.3 log PFU/ml or 9.8 log PFU/ml for up to 2 min before inoculation with E. coli O157:H7; (2) spray-application of EcoShield™ (9.3 log PFU/ml) to lettuce after inoculation with E. coli O157:H7 (4.10 CFU/cm2) following exposure to 50 μg/ml chlorine for 30 sec. After immersion studies, lettuce was spot-inoculated with E. coli O157:H7 (2.38 CFU/cm2). Phage-treated, inoculated lettuce pieces were stored at 4°C for and analyzed for E. coli O157:H7 populations for up to 7 d. Immersion of lettuce in 9.8 log PFU/ml EcoShield™ for 2 min significantly (p < 0.05) reduced E. coli O157:H7 populations after 24 h when stored at 4°C compared with controls. Immersion of lettuce in suspensions containing high concentrations of EcoShield™ (9.8 log PFU/ml) resulted in the deposition of high concentrations (7.8 log log PFU/cm2) of bacteriophages on the surface of fresh cut lettuce, potentially contributing to the efficacy of the lytic phages on lettuce. Spraying phages on to inoculated fresh cut lettuce after being washed in hypochlorite solution was significantly more effective in reducing E. coli O157:H7 populations (2.22 log CFU/cm2) on day 0 compared with control treatments (4.10 log CFU/cm2). Both immersion and spray treatments provided protection from E. coli O157:H7 contamination on lettuce, but spray application of lytic bacteriophages to lettuce was more effective in immediately reducing E. coli O157:H7 populations fresh cut lettuce. PMID:23819106

  10. Biological characteristics and probiotic effect of Leuconostoc lactis strain isolated from the intestine of black porgy fish

    PubMed Central

    Zhang, Wei; Liu, Mingqi; Dai, Xianjun

    2013-01-01

    A strain of lactic acid bacteria, Leuconostoc lactis, was isolated from the intestinal tract of black porgy, Sparus macrocephalus, and identified by conventional biochemical characteristics and 16S rDNA gene sequence analysis. The isolated strain had the ability of bile tolerance and resistance to low pH, and survived well in the trypsinase and pepsin solution. But the highly concentrated dose of trypsinase and pepsin affect the viability of the isolated strain. The isolate was resistant to several antibiotics, including Cephalothin, Ceftriaxone, Imipenem and Tobramycin. The isolate could auto-aggregate itself and coaggregate with other bacteria in vitro. The autoaggregation percentage increased to 23.29% after 20 h of incubation. The percentage of coaggregation were respectively 31.21%, 29.44%, 10.74%, 16.49%, 24.36%, 24.41% and 20.99% for Vibrio parahaemolyticus, Listeria monocytogenes, Escherichia coli O157, Salmonella typhimurium, Shigella, Staphylococcus aureus and Proteusbacillus vulgaris after 20 h incubation of a mixed suspension. The supernatant of the strain inhibited the growth of several pathogens, such as V.parahaemolyticus, Vibrio harveyi, Vibrio alginolyticus, Staphylococcus aureus, Escherichia coli O157, Salmonella typhimurium, Bacillus subtilis, Proteusbacillus vulgaris and Shigella. These results indicated that the isolate, Leuconostoc lactis, might be an attractive candidate for perspectival strain for probiotics in marine aquaculture. PMID:24516418

  11. Lettuce Cultivar Mediates Both Phyllosphere and Rhizosphere Activity of Escherichia coli O157:H7

    PubMed Central

    Quilliam, Richard S.; Williams, A. Prysor; Jones, Davey L.

    2012-01-01

    Plant roots and leaves can be colonized by human pathogenic bacteria, and accordingly some of the largest outbreaks of foodborne illness have been associated with salad leaves contaminated by E. coli O157. Integrated disease management strategies often exploit cultivar resistance to provide a level of protection from economically important plant pathogens; however, there is limited evidence of whether the genotype of the plant can also influence the extent of E. coli O157 colonization. To determine cultivar-specific effects on colonization by E. coli O157, we used 12 different cultivars of lettuce inoculated with a chromosomally lux-marked strain of E. coli O157:H7. Lettuce seedlings grown gnotobiotically in vitro did exhibit a differential cultivar-specific response to E. coli O157 colonization, although importantly there was no relationship between metabolic activity (measured as bioluminescence) and cell numbers. Metabolic activity was highest and lowest on the cultivars Vaila-winter gem and Dazzle respectively, and much higher in endophytic and tightly bound cells than in epiphytic and loosely bound cells. The cultivar effect was also evident in the rhizosphere of plants grown in compost, which suggests that cultivar-specific root exudate influences E. coli O157 activity. However, the influence of cultivar in the rhizosphere was the opposite to that in the phyllosphere, and the higher number and activity of E. coli O157 cells in the rhizosphere may be a consequence of them not being able to gain entry to the plant as effectively. If metabolic activity in the phyllosphere corresponds to a more prepared state of infectivity during human consumption, leaf internalization of E. coli O157 may pose more of a public health risk than leaf surface contamination alone. PMID:22439006

  12. Rapid Detection of Escherichia coli O157 and Shiga Toxins by Lateral Flow Immunoassays.

    PubMed

    Wang, Jinliang; Katani, Robab; Li, Lingling; Hegde, Narasimha; Roberts, Elisabeth L; Kapur, Vivek; DebRoy, Chitrita

    2016-01-01

    Shiga toxin-producing Escherichia coli O157:H7 (STEC) cause food-borne illness that may be fatal. STEC strains enumerate two types of potent Shiga toxins (Stx1 and Stx2) that are responsible for causing diseases. It is important to detect the E. coli O157 and Shiga toxins in food to prevent outbreak of diseases. We describe the development of two multi-analyte antibody-based lateral flow immunoassays (LFIA); one for the detection of Stx1 and Stx2 and one for the detection of E. coli O157 that may be used simultaneously to detect pathogenic E. coli O157:H7. The LFIA strips were developed by conjugating nano colloidal gold particles with monoclonal antibodies against Stx1 and Stx2 and anti-lipid A antibodies to capture Shiga toxins and O157 antigen, respectively. Our results indicate that the LFIA for Stx is highly specific and detected Stx1 and Stx2 within three hours of induction of STEC with ciprofloxacin at 37 °C. The limit of detection for E. coli O157 LFIA was found to be 10⁵ CFU/mL in ground beef spiked with the pathogen. The LFIAs are rapid, accurate and easy to use and do not require sophisticated equipment or trained personnel. Following the assay, colored bands on the membrane develop for end-point detection. The LFIAs may be used for screening STEC in food and the environment. PMID:27023604

  13. Rapid Detection of Escherichia coli O157 and Shiga Toxins by Lateral Flow Immunoassays

    PubMed Central

    Wang, Jinliang; Katani, Robab; Li, Lingling; Hegde, Narasimha; Roberts, Elisabeth L.; Kapur, Vivek; DebRoy, Chitrita

    2016-01-01

    Shiga toxin-producing Escherichia coli O157:H7 (STEC) cause food-borne illness that may be fatal. STEC strains enumerate two types of potent Shiga toxins (Stx1 and Stx2) that are responsible for causing diseases. It is important to detect the E. coli O157 and Shiga toxins in food to prevent outbreak of diseases. We describe the development of two multi-analyte antibody-based lateral flow immunoassays (LFIA); one for the detection of Stx1 and Stx2 and one for the detection of E. coli O157 that may be used simultaneously to detect pathogenic E. coli O157:H7. The LFIA strips were developed by conjugating nano colloidal gold particles with monoclonal antibodies against Stx1 and Stx2 and anti-lipid A antibodies to capture Shiga toxins and O157 antigen, respectively. Our results indicate that the LFIA for Stx is highly specific and detected Stx1 and Stx2 within three hours of induction of STEC with ciprofloxacin at 37 °C. The limit of detection for E. coli O157 LFIA was found to be 105 CFU/mL in ground beef spiked with the pathogen. The LFIAs are rapid, accurate and easy to use and do not require sophisticated equipment or trained personnel. Following the assay, colored bands on the membrane develop for end-point detection. The LFIAs may be used for screening STEC in food and the environment. PMID:27023604

  14. Meat Science and Muscle Biology Symposium: Development of bacteriophage treatments to reduce Escherichia coli O157:H7 contamination of beef products and produce.

    PubMed

    Hong, Y; Pan, Y; Ebner, P D

    2014-04-01

    Escherichia coli O157:H7 remains a foodborne pathogen of concern with infections associated with products ranging from ground beef to produce to processed foods. We previously demonstrated that phage-based technologies could reduce foodborne pathogen colonization in live animals. Here, we examined if a 3-phage cocktail could reduce E. coli O157:H7 in experimentally contaminated ground beef, spinach, and cheese. The 3 phages were chosen from our E. coli O157:H7 phage library based on their distinct origins of isolation, lytic ranges, and rapid growth (40- to 50-min life cycle). Two phages belonged to the Myoviridae family and the other phage belonged to the Siphoviridae family. The phage cocktail was added to ground beef, spinach leaves, and cheese slices contaminated with E. coli O157:H7 (10(7) cfu) at a multiplicity of infection of 1. Phage treatment reduced (P < 0.05) the concentrations of E. coli O157:H7 by 1.97 log10 cfu/mL in ground beef when stored at room temperature (24 °C) for 24 h, 0.48 log10 cfu/mL at refrigeration (4 °C), and 0.56 log10 cfu/mL in undercooked condition (internal temperature of 46 °C). Likewise, phage treatment reduced (P < 0.05) E. coli O157:H7 by 3.28, 2.88, and 2.77 log10 cfu/mL in spinach when stored at room temperature for 24, 48, and 72 h, respectively. Phage treatment, however, did not reduce E. coli O157:H7 concentrations in contaminated cheese. Additionally, 3 phage-resistant E. coli O157:H7 strains (309-PR [phage resistant] 1, 309-PR4, and 502-PR5) were isolated and characterized to test if phage resistance could limit long-term use of phages as biocontrol agents. Growth kinetics and adsorption assays indicated that phage resistance in strains 309-PR4 and 502-PR5 was mediated, at least in part, by prevention of phage adsorption. Phage resistance in strain 309-PR1 was the result of limited phage proliferation. Phage resistance was stably maintained in vitro throughout a 4-d subculture period in the absence of phage. No

  15. Protein kinase C mediates enterohemorrhagic Escherichia coli O157:H7-induced attaching and effacing lesions.

    PubMed

    Shen-Tu, Grace; Kim, Hyunhee; Liu, Mingyao; Johnson-Henry, Kathene C; Sherman, Philip M

    2014-04-01

    Enterohemorrhagic Escherichia coli serotype O157:H7 causes outbreaks of diarrhea, hemorrhagic colitis, and the hemolytic-uremic syndrome. E. coli O157:H7 intimately attaches to epithelial cells, effaces microvilli, and recruits F-actin into pedestals to form attaching and effacing lesions. Lipid rafts serve as signal transduction platforms that mediate microbe-host interactions. The aims of this study were to determine if protein kinase C (PKC) is recruited to lipid rafts in response to E. coli O157:H7 infection and what role it plays in attaching and effacing lesion formation. HEp-2 and intestine 407 tissue culture epithelial cells were challenged with E. coli O157:H7, and cell protein extracts were then separated by buoyant density ultracentrifugation to isolate lipid rafts. Immunoblotting for PKC was performed, and localization in lipid rafts was confirmed with an anti-caveolin-1 antibody. Isoform-specific PKC small interfering RNA (siRNA) was used to determine the role of PKC in E. coli O157:H7-induced attaching and effacing lesions. In contrast to uninfected cells, PKC was recruited to lipid rafts in response to E. coli O157:H7. Metabolically active bacteria and cells with intact lipid rafts were necessary for the recruitment of PKC. PKC recruitment was independent of the intimin gene, type III secretion system, and the production of Shiga toxins. Inhibition studies, using myristoylated PKCζ pseudosubstrate, revealed that atypical PKC isoforms were activated in response to the pathogen. Pretreating cells with isoform-specific PKC siRNA showed that PKCζ plays a role in E. coli O157:H7-induced attaching and effacing lesions. We concluded that lipid rafts mediate atypical PKC signal transduction responses to E. coli O157:H7. These findings contribute further to the understanding of the complex array of microbe-eukaryotic cell interactions that occur in response to infection. PMID:24491575

  16. Highly Virulent Non-O157 Enterohemorrhagic Escherichia coli (EHEC) Serotypes Reflect Similar Phylogenetic Lineages, Providing New Insights into the Evolution of EHEC

    PubMed Central

    Eichhorn, Inga; Heidemanns, Katrin; Semmler, Torsten; Kinnemann, Bianca; Mellmann, Alexander; Harmsen, Dag; Anjum, Muna F.; Schmidt, Herbert; Fruth, Angelika; Valentin-Weigand, Peter; Heesemann, Jürgen; Suerbaum, Sebastian; Karch, Helge

    2015-01-01

    Enterohemorrhagic Escherichia coli (EHEC) is the causative agent of bloody diarrhea and extraintestinal sequelae in humans, most importantly hemolytic-uremic syndrome (HUS) and thrombotic thrombocytopenic purpura (TTP). Besides the bacteriophage-encoded Shiga toxin gene (stx), EHEC harbors the locus of enterocyte effacement (LEE), which confers the ability to cause attaching and effacing lesions. Currently, the vast majority of EHEC infections are caused by strains belonging to five O serogroups (the “big five”), which, in addition to O157, the most important, comprise O26, O103, O111, and O145. We hypothesize that these four non-O157 EHEC serotypes differ in their phylogenies. To test this hypothesis, we used multilocus sequence typing (MLST) to analyze a large collection of 250 isolates of these four O serogroups, which were isolated from diseased as well as healthy humans and cattle between 1952 and 2009. The majority of the EHEC isolates of O serogroups O26 and O111 clustered into one sequence type complex, STC29. Isolates of O103 clustered mainly in STC20, and most isolates of O145 were found within STC32. In addition to these EHEC strains, STC29 also included stx-negative E. coli strains, termed atypical enteropathogenic E. coli (aEPEC), yet another intestinal pathogenic E. coli group. The finding that aEPEC and EHEC isolates of non-O157 O serogroups share the same phylogeny suggests an ongoing microevolutionary scenario in which the phage-encoded Shiga toxin gene stx is transferred between aEPEC and EHEC. As a consequence, aEPEC strains of STC29 can be regarded as post- or pre-EHEC isolates. Therefore, STC29 incorporates phylogenetic information useful for unraveling the evolution of EHEC. PMID:26231647

  17. Highly Virulent Non-O157 Enterohemorrhagic Escherichia coli (EHEC) Serotypes Reflect Similar Phylogenetic Lineages, Providing New Insights into the Evolution of EHEC.

    PubMed

    Eichhorn, Inga; Heidemanns, Katrin; Semmler, Torsten; Kinnemann, Bianca; Mellmann, Alexander; Harmsen, Dag; Anjum, Muna F; Schmidt, Herbert; Fruth, Angelika; Valentin-Weigand, Peter; Heesemann, Jürgen; Suerbaum, Sebastian; Karch, Helge; Wieler, Lothar H

    2015-10-01

    Enterohemorrhagic Escherichia coli (EHEC) is the causative agent of bloody diarrhea and extraintestinal sequelae in humans, most importantly hemolytic-uremic syndrome (HUS) and thrombotic thrombocytopenic purpura (TTP). Besides the bacteriophage-encoded Shiga toxin gene (stx), EHEC harbors the locus of enterocyte effacement (LEE), which confers the ability to cause attaching and effacing lesions. Currently, the vast majority of EHEC infections are caused by strains belonging to five O serogroups (the "big five"), which, in addition to O157, the most important, comprise O26, O103, O111, and O145. We hypothesize that these four non-O157 EHEC serotypes differ in their phylogenies. To test this hypothesis, we used multilocus sequence typing (MLST) to analyze a large collection of 250 isolates of these four O serogroups, which were isolated from diseased as well as healthy humans and cattle between 1952 and 2009. The majority of the EHEC isolates of O serogroups O26 and O111 clustered into one sequence type complex, STC29. Isolates of O103 clustered mainly in STC20, and most isolates of O145 were found within STC32. In addition to these EHEC strains, STC29 also included stx-negative E. coli strains, termed atypical enteropathogenic E. coli (aEPEC), yet another intestinal pathogenic E. coli group. The finding that aEPEC and EHEC isolates of non-O157 O serogroups share the same phylogeny suggests an ongoing microevolutionary scenario in which the phage-encoded Shiga toxin gene stx is transferred between aEPEC and EHEC. As a consequence, aEPEC strains of STC29 can be regarded as post- or pre-EHEC isolates. Therefore, STC29 incorporates phylogenetic information useful for unraveling the evolution of EHEC. PMID:26231647

  18. SHIGA TOXIN AND THE SHIGA TOXIN-ENCODING PHAGE DO NOT FACILITATE E. COLI O157:H7 COLONIZATION IN SHEEP

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Isogenic strains of E. coli O157:H7, missing either stx2 or the entire stx2 encoding phage, were compared with the parent strain for their ability to colonize sheep. The absence of the phage or of the Shiga toxin did not significantly impact the magnitude or duration of shedding of E. coli O157:H7....

  19. Efficacy of integrated treatment of UV light and low dose gamma irradiation on Escherichia coli O157:H7 and Salmonella enterica on grape tomatoes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Efficacy of integrated treatment of UVC and low dose Gamma irradiation to inactivate mixed Strains of Escherichia coli O157:H7 and Salmonella enterica inoculated on whole Grape tomatoes was evaluated. A mixed bacterial cocktail composed of a three strain mixture of E. coli O157:H7 (C9490, E02128 an...

  20. Is Shiga Toxin-Negative Escherichia coli O157:H7 Enteropathogenic or Enterohemorrhagic Escherichia coli? Comprehensive Molecular Analysis Using Whole-Genome Sequencing.

    PubMed

    Ferdous, Mithila; Zhou, Kai; Mellmann, Alexander; Morabito, Stefano; Croughs, Peter D; de Boer, Richard F; Kooistra-Smid, Anna M D; Rossen, John W A; Friedrich, Alexander W

    2015-11-01

    The ability of Escherichia coli O157:H7 to induce cellular damage leading to disease in humans is related to numerous virulence factors, most notably the stx gene, encoding Shiga toxin (Stx) and carried by a bacteriophage. Loss of the Stx-encoding bacteriophage may occur during infection or culturing of the strain. Here, we collected stx-positive and stx-negative variants of E. coli O157:H7/NM (nonmotile) isolates from patients with gastrointestinal complaints. Isolates were characterized by whole-genome sequencing (WGS), and their virulence properties and phylogenetic relationship were determined. Because of the presence of the eae gene but lack of the bfpA gene, the stx-negative isolates were considered atypical enteropathogenic E. coli (aEPEC). However, they had phenotypic characteristics similar to those of the Shiga toxin-producing E. coli (STEC) isolates and belonged to the same sequence type, ST11. Furthermore, EPEC and STEC isolates shared similar virulence genes, the locus of enterocyte effacement region, and plasmids. Core genome phylogenetic analysis using a gene-by-gene typing approach showed that the sorbitol-fermenting (SF) stx-negative isolates clustered together with an SF STEC isolate and that one non-sorbitol-fermenting (NSF) stx-negative isolate clustered together with NSF STEC isolates. Therefore, these stx-negative isolates were thought either to have lost the Stx phage or to be a progenitor of STEC O157:H7/NM. As detection of STEC infections is often based solely on the identification of the presence of stx genes, these may be misdiagnosed in routine laboratories. Therefore, an improved diagnostic approach is required to manage identification, strategies for treatment, and prevention of transmission of these potentially pathogenic strains. PMID:26311863

  1. Is Shiga Toxin-Negative Escherichia coli O157:H7 Enteropathogenic or Enterohemorrhagic Escherichia coli? Comprehensive Molecular Analysis Using Whole-Genome Sequencing

    PubMed Central

    Ferdous, Mithila; Zhou, Kai; Mellmann, Alexander; Morabito, Stefano; Croughs, Peter D.; de Boer, Richard F.; Kooistra-Smid, Anna M. D.; Friedrich, Alexander W.

    2015-01-01

    The ability of Escherichia coli O157:H7 to induce cellular damage leading to disease in humans is related to numerous virulence factors, most notably the stx gene, encoding Shiga toxin (Stx) and carried by a bacteriophage. Loss of the Stx-encoding bacteriophage may occur during infection or culturing of the strain. Here, we collected stx-positive and stx-negative variants of E. coli O157:H7/NM (nonmotile) isolates from patients with gastrointestinal complaints. Isolates were characterized by whole-genome sequencing (WGS), and their virulence properties and phylogenetic relationship were determined. Because of the presence of the eae gene but lack of the bfpA gene, the stx-negative isolates were considered atypical enteropathogenic E. coli (aEPEC). However, they had phenotypic characteristics similar to those of the Shiga toxin-producing E. coli (STEC) isolates and belonged to the same sequence type, ST11. Furthermore, EPEC and STEC isolates shared similar virulence genes, the locus of enterocyte effacement region, and plasmids. Core genome phylogenetic analysis using a gene-by-gene typing approach showed that the sorbitol-fermenting (SF) stx-negative isolates clustered together with an SF STEC isolate and that one non-sorbitol-fermenting (NSF) stx-negative isolate clustered together with NSF STEC isolates. Therefore, these stx-negative isolates were thought either to have lost the Stx phage or to be a progenitor of STEC O157:H7/NM. As detection of STEC infections is often based solely on the identification of the presence of stx genes, these may be misdiagnosed in routine laboratories. Therefore, an improved diagnostic approach is required to manage identification, strategies for treatment, and prevention of transmission of these potentially pathogenic strains. PMID:26311863

  2. Escherichia coli O157:H7 genetic diversity in bovine fecal samples.

    PubMed

    Jacob, M E; Almes, K M; Shi, X; Sargeant, J M; Nagaraja, T G

    2011-07-01

    Escherichia coli O157:H7 causes foodborne illness in humans; cattle are considered a primary reservoir for the organism, and transmission is often through contaminated food products or water. The objective of this study was to determine the genetic diversity of E. coli O157:H7 within a single individual bovine fecal sample based on pulsed-field gel electrophoresis (PFGE) typing. Fecal samples (n=601) were collected from dairy and beef cattle at three separate facilities, and E. coli O157:H7 was isolated by enrichment, immunomagnetic separation, and plating on selective medium. The prevalence of E. coli O157:H7 was 46 (7.7%) of 601. From each positive fecal sample, up to 10 putative colonies were tested, and isolates from samples with at least seven positive colonies were subtyped using PFGE and tested for six major virulence genes by multiplex PCR. A total of 254 E. coli O157:H7 isolates from 27 samples met these criteria and were included in PFGE analysis. Fifteen PFGE subtypes (<100% Dice similarity) were detected among the 254 isolates, and there were no common subtypes between the three locations. Seven (26%) of 27 fecal samples had E. coli O157:H7 isolates with different PFGE subtypes (mean=2.1) within the same sample. The virulence gene profiles of different isolates from the same sample were always identical, regardless of the number of PFGE types. The results of this study suggest that determining the PFGE pattern of a single isolate from a bovine sample may not be sufficient when comparing isolates from feces, hides, or carcasses, because multiple PFGE subtypes are present. PMID:21740722

  3. Persistence of Escherichia coli O157:H7 and its mutants in soils.

    PubMed

    Ma, Jincai; Ibekwe, A Mark; Yi, Xuan; Wang, Haizhen; Yamazaki, Akihiro; Crowley, David E; Yang, Ching-Hong

    2011-01-01

    The persistence of Shiga toxin-producing E. coli O157:H7 in the environment poses a serious threat to public health. However, the role of Shiga toxins and other virulence factors in the survival of E. coli O157:H7 is poorly defined. The aim of this study was to determine if the virulence factors, stx₁, stx₂, stx₁₋₂, and eae in E. coli O157:H7 EDL933 play any significant role in the growth of this pathogen in rich media and in soils. Isogenic deletion mutants that were missing one of four virulence factors, stx₁, stx₂, stx₁₋₂, and eae in E. coli O157:H7 EDL933 were constructed, and their growth in rich media and survival in soils with distinct texture and chemistry were characterized. The survival data were successfully analyzed using Double Weibull model, and the modeling parameters of the mutant strains were not significantly different from those of the wild type. The calculated T(d) (time needed to reach the detection limit, 100 CFU/g soil) for loamy sand, sandy loam, and silty clay was 32, 80, and 110 days, respectively. It was also found that T(d) was positively correlated with soil structure (e.g. clay content), and soil chemistry (e.g. total nitrogen, total carbon, and water extractable organic carbon). The results of this study showed that the possession of Shiga toxins and intimin in E. coli O157:H7 might not play any important role in its survival in soils. The double deletion mutant of E. coli O157:H7 (stx₁⁻stx₂⁻) may be a good substitute to use for the investigation of transport, fate, and survival of E. coli O157:H7 in the environment where the use of pathogenic strains are prohibited by law since the mutants showed the same characteristics in both culture media and environmental samples. PMID:21826238

  4. Spread and change in stress resistance of Shiga toxin-producing Escherichia coli O157 on fungal colonies

    PubMed Central

    Lee, Ken-ichi; Kobayashi, Naoki; Watanabe, Maiko; Sugita-Konishi, Yoshiko; Tsubone, Hirokazu; Kumagai, Susumu; Hara-Kudo, Yukiko

    2014-01-01

    To elucidate the effect of fungal hyphae on the behaviour of Shiga toxin-producing Escherichia coli (STEC) O157, the spread and change in stress resistance of the bacterium were evaluated after coculture with 11 species of food-related fungi including fermentation starters. Spread distances of STEC O157 varied depending on the co-cultured fungal species, and the motile bacterial strain spread for longer distances than the non-motile strain. The population of STEC O157 increased when co-cultured on colonies of nine fungal species but decreased on colonies of Emericella nidulans and Aspergillus ochraceus. Confocal scanning microscopy visualization of green fluorescent protein-tagged STEC O157 on fungal hyphae revealed that the bacterium colonized in the water film that existed on and between hyphae. To investigate the physiological changes in STEC O157 caused by co-culturing with fungi, the bacterium was harvested after 7 days of co-culturing and tested for acid resistance. After co-culture with eight fungal species, STEC O157 showed greater acid resistance compared to those cultured without fungi. Our results indicate that fungal hyphae can spread the contamination of STEC O157 and can also enhance the stress resistance of the bacteria. PMID:23919289

  5. Diverse Genetic Markers Concordantly Identify Bovine Origin Escherichia coli O157 Genotypes Underrepresented in Human Disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Genetic markers previously reported to occur at significantly different frequencies in isolates of Escherichia coli O157:H7 obtained from cattle and from clinically affected humans are congruent and delineate at least five groups. Isolates in three of these groups consistently carry one or more mark...

  6. Survival of Escherichia coli O157:H7 during manufacture and storage of white brined cheese.

    PubMed

    Osaili, Tareq M; Al-Nabulsi, Anas A; Olaimat, Amin N; Shaker, Reyad R; Taha, Mohammad; Holley, Richard A

    2014-09-01

    Escherichia coli O157:H7 is a major foodborne pathogen that causes severe disease in humans. Survival of E. coli O157:H7 during processing and storage of white brined cheese was investigated. Cheeses were prepared using pasteurized milk inoculated with a 4 strain E. coli O157:H7 cocktail (7 log(10) CFU/g) with or without yogurt starter culture (Lactobacillus delbrueckii ssp. bulgaricus and Streptococcus salivarius ssp. thermophilus) and stored in 10% or 15% NaCl brine at 10 and 21 ºC for 28 d. NaCl concentration, water activity (a(w)), pH, and numbers of E. coli O157:H7 and lactic acid bacteria (LAB) were determined in cheese and brine. E. coli O157:H7 was able to survive in cheese stored in both brines at 10 and 21 ºC regardless of the presence of starter LAB, although the latter significantly enhanced E. coli O157:H7 reduction in cheese or its brine at 10 ºC. E. coli O157:H7 numbers were reduced by 2.6 and 3.4 log(10) CFU/g in cheese stored in 10% and 15% NaCl brine, respectively, in the presence of starter LAB and by 1.4 and 2.3 log(10) CFU/g, respectively, in the absence of starter LAB at 10 ºC. The pathogen survived, but at lower numbers in the brines. The salt concentration of cheese stored in 10% brine remained about 5% during ripening, but in 15% brine, the NaCl level increased 1.6% to 8.1% (w/w) by 28 d. Values of pH and a(w) slightly decreased 1 d after exposure to brine and reached 5.5 to 6.6 and 0.88 to 0.94, respectively, in all treatments. PMID:25134419

  7. Association of Escherichia coli O157:H7 tir polymorphisms with human infection

    PubMed Central

    Bono, James L; Keen, James E; Clawson, Michael L; Durso, Lisa M; Heaton, Michael P; Laegreid, William W

    2007-01-01

    Background Emerging molecular, animal model and epidemiologic evidence suggests that Shiga-toxigenic Escherichia coli O157:H7 (STEC O157) isolates vary in their capacity to cause human infection and disease. The translocated intimin receptor (tir) and intimin (eae) are virulence factors and bacterial receptor-ligand proteins responsible for tight STEC O157 adherence to intestinal epithelial cells. They represent logical genomic targets to investigate the role of sequence variation in STEC O157 pathogenesis and molecular epidemiology. The purposes of this study were (1) to identify tir and eae polymorphisms in diverse STEC O157 isolates derived from clinically ill humans and healthy cattle (the dominant zoonotic reservoir) and (2) to test any observed tir and eae polymorphisms for association with human (vs bovine) isolate source. Results Five polymorphisms were identified in a 1,627-bp segment of tir. Alleles of two tir polymorphisms, tir 255 T>A and repeat region 1-repeat unit 3 (RR1-RU3, presence or absence) had dissimilar distributions among human and bovine isolates. More than 99% of 108 human isolates possessed the tir 255 T>A T allele and lacked RR1-RU3. In contrast, the tir 255 T>A T allele and RR1-RU3 absence were found in 55% and 57%, respectively, of 77 bovine isolates. Both polymorphisms associated strongly with isolate source (p < 0.0001), but not by pulsed field gel electrophoresis type or by stx1 and stx2 status (as determined by PCR). Two eae polymorphisms were identified in a 2,755-bp segment of 44 human and bovine isolates; 42 isolates had identical eae sequences. The eae polymorphisms did not associate with isolate source. Conclusion Polymorphisms in tir but not eae predict the propensity of STEC O157 isolates to cause human clinical disease. The over-representation of the tir 255 T>A T allele in human-derived isolates vs the tir 255 T>A A allele suggests that these isolates have a higher propensity to cause disease. The high frequency of bovine

  8. Role of Escherichia coli O157:H7 Virulence Factors in Colonization at the Bovine Terminal Rectal Mucosa

    PubMed Central

    Sheng, Haiqing; Lim, Ji Youn; Knecht, Hannah J.; Li, Jie; Hovde, Carolyn J.

    2006-01-01

    The human pathogen Escherichia coli O157:H7 causes hemorrhagic colitis and life-threatening sequelae and transiently colonizes healthy cattle at the terminal rectal mucosa. This study analyzed virulence factors important for the clinical manifestations of human E. coli O157:H7 infection for their contribution to the persistence of E. coli in cattle. The colonizing ability of E. coli O157:H7 was compared with those of nonpathogenic E. coli K-12 and isogenic deletion mutants missing Shiga toxin (Stx), the adhesin intimin, its receptor Tir, hemolysin, or the ∼92-kb pO157. Fully ruminant steers received a single rectal application of one E. coli strain so that effects of mucosal attachment and survival at the terminal rectum could be measured without the impact of bacterial passage through the entire gastrointestinal tract. Colonization was monitored by sensitive recto-anal junction mucosal swab culture. Nonpathogenic E. coli K-12 did not colonize as well as E. coli O157:H7 at the bovine terminal rectal mucosa. The E. coli O157:H7 best able to persist had intimin, Tir, and the pO157. Strains missing even one of these factors were recovered in lower numbers and were cleared faster than the wild type. In contrast, E. coli O157:H7 strains that were missing Stx or hemolysin colonized like the wild type. For these three strains, the number of bacteria increased between days 1 and 4 postapplication and then decreased slowly. In contrast, the numbers of noncolonizing strains (K-12, Δtir, and Δeae) decreased from the day of application. These patterns consistently predicted long-term colonization or clearance of the bacteria from the bovine terminal rectal mucosa. PMID:16861656

  9. Biofilm formation and sanitizer resistance of Escherichia coli 0157:H7 strains isolated from "High Event Period" meat contamination

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the meat industry, a “High Event Period” (HEP) is defined as a time period during which commercial meat plants experience a higher than usual rate of E. coli O157:H7 contamination. Genetic analysis indicated that within a HEP, most of the E. coli O157:H7 strains belong to a singular dominant str...

  10. Inhibiting the Growth of Escherichia coli O157:H7 in Beef, Pork, and Chicken Meat using a Bacteriophage

    PubMed Central

    Seo, Jina; Seo, Dong Joo; Oh, Hyejin; Jeon, Su Been; Oh, Mi-Hwa; Choi, Changsun

    2016-01-01

    This study aimed to inhibit Escherichia coli (E. coli) O157:H7 artificially contaminated in fresh meat using bacteriophage. Among 14 bacteriophages, the highly lytic bacteriophage BPECO19 strain was selected to inhibit E. coli O157:H7 in artificially contaminated meat samples. Bacteriophage BPECO19 significantly reduced E. coli O157:H7 bacterial load in vitro in a multiplicity of infection (MOI)-dependent manner. E. coli O157:H7 was completely inhibited only in 10 min in vitro by the treatment of 10,000 MOI BPECO19. The treatment of BPECO19 at 100,000 MOI completely reduced 5 Log CFU/cm2 E. coli O157:H7 bacterial load in beef and pork at 4 and 8h, respectively. In chicken meat, a 4.65 log reduction of E. coli O157:H7 was observed at 4 h by 100,000 MOI. The treatment of single bacteriophage BPECO19 was an effective method to control E. coli O157:H7 in meat samples. PMID:27194926

  11. Effect of Neem (Azadirachta indica) on the Survival of Escherichia coli O157:H7 in Dairy Manure.

    PubMed

    Ravva, Subbarao V; Korn, Anna

    2015-07-01

    Escherichia coli O157:H7 (EcO157) shed in cattle manure can survive for extended periods of time and intervention strategies to control this pathogen at the source are critical as produce crops are often grown in proximity to animal raising operations. This study evaluated whether neem (Azadirachta indica), known for its antimicrobial and insecticidal properties, can be used to amend manure to control EcO157. The influence of neem materials (leaf, bark, and oil) on the survival of an apple juice outbreak strain of EcO157 in dairy manure was monitored. Neem leaf and bark supplements eliminated the pathogen in less than 10 d with a D-value (days for 90% elimination) of 1.3 d. In contrast, nearly 4 log CFU EcO157/g remained after 10 d in neem-free manure control. The ethyl acetate extractable fraction of neem leaves was inhibitory to the growth of EcO157 in LB broth. Azadirachtin, a neem product with insect antifeedant properties, failed to inhibit EcO157. Application of inexpensive neem supplements to control pathogens in manure and possibly in produce fields may be an option for controlling the transfer of foodborne pathogens from farm to fork. PMID:26184255

  12. Effect of Neem (Azadirachta indica) on the Survival of Escherichia coli O157:H7 in Dairy Manure

    PubMed Central

    Ravva, Subbarao V.; Korn, Anna

    2015-01-01

    Escherichia coli O157:H7 (EcO157) shed in cattle manure can survive for extended periods of time and intervention strategies to control this pathogen at the source are critical as produce crops are often grown in proximity to animal raising operations. This study evaluated whether neem (Azadirachta indica), known for its antimicrobial and insecticidal properties, can be used to amend manure to control EcO157. The influence of neem materials (leaf, bark, and oil) on the survival of an apple juice outbreak strain of EcO157 in dairy manure was monitored. Neem leaf and bark supplements eliminated the pathogen in less than 10 d with a D-value (days for 90% elimination) of 1.3 d. In contrast, nearly 4 log CFU EcO157/g remained after 10 d in neem-free manure control. The ethyl acetate extractable fraction of neem leaves was inhibitory to the growth of EcO157 in LB broth. Azadirachtin, a neem product with insect antifeedant properties, failed to inhibit EcO157. Application of inexpensive neem supplements to control pathogens in manure and possibly in produce fields may be an option for controlling the transfer of foodborne pathogens from farm to fork. PMID:26184255

  13. A novel approach to investigate the uptake and internalization of Escherichia coli O157:H7 in spinach cultivated in soil and hydroponic media

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Internalization of E. coli O157:H7 into spinach plants through root uptake is a potential route of contamination. A Tn7-based plasmid vector was used to insert the green fluorescent protein (gfp) gene into the attTn7 site in the E. coli chromosome. Three gfp-labeled E. coli inocula, O157:H7 strains ...

  14. Comparison of the molecular genotypes of Escherichia coli O157:H7 from the hides of beef cattle in different regions of North America

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cattle hides become contaminated with E. coli O157:H7 via pathogen transmission in the feedlot, during transport, and in the lairage environment at the processing facility and the bacteria can be transferred to beef carcasses during processing. Several studies have shown that E. coli O157:H7 strain...

  15. Serodiagnosis Using Microagglutination Assay during the Food-Poisoning Outbreak in Japan Caused by Consumption of Raw Beef Contaminated with Enterohemorrhagic Escherichia coli O111 and O157

    PubMed Central

    Isobe, Junko; Shima, Tomoko; Kanatani, Jun-ichi; Kimata, Keiko; Shimizu, Miwako; Kobayashi, Naoto; Tanaka, Tomoko; Iyoda, Sunao; Ohnishi, Makoto; Sata, Tetsutaro

    2014-01-01

    A microagglutination (MA) assay to identify antibodies to Escherichia coli O111 and O157 was conducted in sera collected from 60 patients during a food-poisoning outbreak affecting 181 patients in Japan which was caused by the consumption of contaminated raw beef. Enterohemorrhagic E. coli (EHEC) O111:H8 and/or O157:H7 was isolated from the stools of some of the patients, but the total rate of positivity for antibodies to O111 (45/60, 75.0%) was significantly higher than that for antibodies to O157 (10/60, 16.7%). The MA titers of antibodies to O111 measured in patients with hemolytic-uremic syndrome and bloody diarrhea were higher than those measured in patients with only diarrhea. In patients from whose stool no isolates of E. coli O111 and O157 were obtained, the positive antibody detection rates were 12/19 (63.2%) for O111 and 2/19 (10.5%) for O157, and the MA titers of antibodies to O111 measured were higher than those to O157. Similarly, the MA titers of antibodies to O111 were significantly higher than those to O157, regardless of the other groups, including groups O111, O111 and O157, and O157. These serodiagnosis results suggest that EHEC O111:H8 stx2 played a primary role in the pathogenesis of this outbreak. Furthermore, our findings suggest that the isolates from the patients' stool specimens were not always the major causative pathogen in patients with multiple EHEC infections, because the sera from patients from whose stools only O157 was isolated were positive for antibodies to O111. Measuring antibodies to E. coli O antigen is helpful especially in cases with multiple EHEC infections, even with a non-O157 serotype. PMID:24452161

  16. Escherichia coli O157:H7 outbreak linked to home-cooked hamburger--California, July 1993.

    PubMed

    1994-04-01

    Although outbreaks of Escherichia coli O157:H7 have been linked to consumption of contaminated ground beef, the organism is rarely isolated from the implicated meat. In addition, most epidemiologic investigations of illness associated with E. coli O157:H7 infections have been directed at restaurant-associated outbreaks, and the sources of infection for sporadic cases rarely have been identified. In July 1993, three cases of culture-confirmed E. coli O157:H7 infection among persons residing in a small community in California were traced to consumption of hamburger purchased from a local grocery store; E. coli O157:H7 was isolated from that meat. This report summarizes the investigation of these cases by local and state public health officials. PMID:8127326

  17. Production and characterisation of monoclonal antibodies specific for Escherichia coli O157:H7.

    PubMed

    Luciani, M; Armillotta, G; Magliulo, M; Portanti, O; Di Febo, T; Di Giannatale, E; Roda, A; Lelli, R

    2006-01-01

    Seven monoclonal antibodies (MAbs) specific for Escherichia coli O157:H7, one of the major causes of haemorrhagic colitis in humans, were produced by immunising Balb/c mice with the strain E. coli O157:H7. These monoclonal antibodies do not cross-react with other bacteria such as Salmonella enterica serovar Typhimurium, E. coli O14, E. coli JM109, S. enterica serovar Enteritidis, S. panama, S. saintpaul, S. derby, S. muenchen, S. bredeney, S. hadar, Yersinia enterocolitica, Proteus vulgaris, Shigella flexneri, Listeria ivanovii, L. monocytogenes 13M, L. innocua, Enterobacter cloacae, E. agglomerans, E. amnigenus, Citrobacter freundii, Escherichia fergussoni or Klebsiella pneumoniae. Of the seven MAbs obtained, MAb 8B8C3 was selected to prepare a high-sensitivity sandwich ELISA method specific for O157:H7. PMID:20429059

  18. Incorporation of Escherichia coli O157:H7 in biofilms with Ralstonia insidiosa, a primary localizer for the development of heterogeneous biofilms

    Technology Transfer Automated Retrieval System (TEKTRAN)

    It is hypothesized that the presence of strong biofilm forming microflora could potentially enhance the survival of Escherichia coli O157:H7 (EcO157) in harsh environment. In this study, a strong biofilm forming bacterium, Ralstonia insidiosa, previously isolated from a fresh-cut produce plant was c...

  19. Non-O157 Shiga toxin-producing Escherichia coli: detection and characterization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Escherichia coli strains that produce Shiga toxins, referred to as Shiga toxin-producing E. coli (STEC) or verotoxigenic E. coli (VTEC) are important food-borne pathogens that cause hemorrhagic colitis (HC) and hemolytic uremic syndrome (HUS). E. coli O157:H7 is a common cause of STEC infection; ho...

  20. Antimicrobial Effect of Water-Soluble Muscadine Seed Extracts on Escherichia coli O157:H7

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Water-soluble extracts were prepared from purple (cultivar Ison) and bronze (cultivar Carlos) muscadine seeds with or without heating. The Ison extracts had strong antimicrobial activity against a cocktail of three strains of Escherichia coli O157:H7. This extract had higher acidity (pH 3.39 to 3.43...

  1. E. COLI O157:H7: HOW CAN WE USE MICROBIAL ECOLOGY TO REDUCE IN CATTLE?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    More than 76 million citizens are sickened each year by consuming foods contaminated with pathogenic bacteria. The most important food-borne pathogen in cattle remains E. coli O157:H7 and its closely related enterohemorrhagic E. coli strains (EHEC) cause more than 90,000 illnesses each year in the ...

  2. Cold Plasma Inactivates Salmonella and Escherichia coli O157:H7 on Fresh Produce

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This presentation will summarize recent advances in cold plasma technology at the USDA’s Eastern Regional Research Center. Cold plasma generated in a gliding arc was applied to outbreak strains of Escherichia coli O157:H7 and Salmonella Stanley inoculated on the surfaces of golden delicious apples. ...

  3. Assessment of commercial chromogenic solid media for the detection of non-O157 Shiga toxin-producing Escherichia coli (STEC).

    PubMed

    Zelyas, Nathan; Poon, Alan; Patterson-Fortin, Laura; Johnson, Roger P; Lee, Winki; Chui, Linda

    2016-07-01

    Detection of Shiga toxin-producing Escherichia coli (STEC) has evolved significantly since the introduction of sorbitol-MacConkey agar. This study compares four chromogenic media (CHROMagar™ STEC, Rainbow® O157 agar, CHROMagar™ O157, and Colorex® O157) in their identification of non-O157 STEC. When 161 non-O157 STEC were directly inoculated onto each medium, detection rates on CHROMagar™ STEC, Rainbow® O157 agar, CHROMagar™ O157 and Colorex® O157 were 90%, 70%, 3.7% and 6.8%, respectively. Tellurite minimal inhibitory concentrations (MICs) correlated with growth on CHROMagar™ STEC as 20 of 22 isolates with poor or no growth had MICs ≤1μg/mL. Stool spiking experiments revealed that CHROMagar™ STEC had the highest recovery of the six most common non-O157 STEC, ranging from 30% (in mucoid stool) to 98% (in watery stool). When using clinical stool samples, CHROMagar™ STEC had a sensitivity, specificity, positive predictive value, and negative predictive value of 84.6%, 87%, 13.9%, and 99.6%, respectively. PMID:27157987

  4. [Presence of Escherichia coli O157:H7, Listeria monocytogenes and Salmonella spp. in food from animal origin in Costa Rica].

    PubMed

    Reuben, Alejandra; Treminio, Hellen; Arias, María Laura; Chaves, Carolina

    2003-12-01

    The presence of Escherichia coli O157:H7, Listeria monocytogenes and Salmonella spp was analyzed in two kinds of food from animal origin in Costa Rica. 100 samples of non pasteurized milk, from the principal producing zones of the country, and 100 samples of chicken giblets, purchased in retail markets, were analyzed according to the methodology described by Food and Drug Administration, 1995. Escherichia coli O157:H7 was analyzed in both kinds of food, while L. monocytogenes was evaluated in raw milk and Salmonella spp. in chicken giblets. Five strains of E. coli O157:H7 were isolated, three of them coming from chicken giblets and the other two from raw milk. 15% positivity for Salmonella spp. was found in chicken giblet samples and 3% positivity for L. monocytogenes in raw milk samples. The results obtained show the importance of the adequate processing of food from animal origin in order to decrease the potential transmission of pathogenic agents. The introduction of Hazard Analysis Critical Control Points system (HACCP) and Good Manufacturing practices in food industry keep on being the principal control measures and inocuity warranty. PMID:15125081

  5. Oral immunization of mice with a glycoconjugate vaccine containing the O157 antigen of Escherichia coli O157:H7 admixed with cholera toxin fails to elicit protection against subsequent colonization by the pathogen.

    PubMed

    Conlan, J W; KuoLee, R; Webb, A; Cox, A D; Perry, M B

    2000-03-01

    It has been postulated that a humoral immune response directed against the O157 antigen of Escherichia coli O157:H7, and expressed in the intestine, might afford protection from colonization and consequent infection by this enteric pathogen. The present study was conducted to determine whether such an immune response can be experimentally generated in mice. To this end, mice were orally immunized with a glycoconjugate vaccine consisting of horse serum albumin and the O157 polysaccharide admixed with the mucosal adjuvant, cholera toxin. Mice consistently developed robust local and systemic immune responses to the cholera toxin adjuvant, but were far from uniformly reactive to the test vaccine. Moreover, vaccinated mice were as susceptible to transient intestinal colonization following challenge with an isolate of E. coli O157:H7 as unvaccinated control mice. These results indicate that this vaccination approach is unlikely to be straightforward in target bovine or human hosts. PMID:10749542

  6. Characterization of a ViI-like phage specific to Escherichia coli O157:H7

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phage vB_EcoM_CBA120 (CBA120) isolated against Escherichia coli O157:H7 from a cattle feedlot is morphologically very similar to the classic phage ViI of Salmonella enterica serovar Typhi. Until recently, little was known genetically or physiologically about the ViI-like phages, and non targeting E...

  7. Microarray analysis of norepinephrine grown E. coli O157:H7

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To examine differences in the transcription profile of Escherichia coli O157:H7 during growth in the presence of catecholamines, the clinical-type isolate EDL933 (ATCC 43895) was grown using an in-vitro culture system made up of moderate initial inoculum and a serum-SAPI based medium. After 5 hrs of...

  8. Escherichia coli O157:H7 gene expression in the presence of the catecholamine norepinephrine

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To examine the effects of the catecholamine norepinephrine (NE) on the expression of virulence factors in Escherichia coli O157:H7, the clinical-type isolate EDL933 (ATCC 43895) was grown in the presence or absence of NE. An in-vitro culture system made up of low initial innocula and a serum-SAPI ba...

  9. Curli fimbriae are conditionally required in Escherichia coli O157:H7 for initial attachment and biofilm formation.

    PubMed

    Carter, Michelle Qiu; Louie, Jacqueline W; Feng, Doris; Zhong, Wayne; Brandl, Maria T

    2016-08-01

    Several species of enteric pathogens produce curli fimbriae, which may affect their interaction with surfaces and other microbes in nonhost environments. Here we used two Escherichia coli O157:H7 outbreak strains with distinct genotypes to understand the role of curli in surface attachment and biofilm formation in several systems relevant to fresh produce production and processing. Curli significantly enhanced the initial attachment of E. coli O157:H7 to spinach leaves and stainless steel surfaces by 5-fold. Curli was also required for E. coli O157:H7 biofilm formation on stainless steel and enhanced biofilm production on glass by 19-27 fold in LB no-salt broth. However, this contribution was not observed when cells were grown in sterile spinach lysates. Furthermore, both strains of E. coli O157:H7 produced minimal biofilms on polypropylene in LB no-salt broth but considerable amounts in spinach lysates. Under the latter conditions, curli appeared to slightly increase biofilm production. Importantly, curli played an essential role in the formation of mixed biofilm by E. coli O157:H7 and plant-associated microorganisms in spinach leaf washes, as revealed by confocal microscopy. Little or no E. coli O157:H7 biofilms were detected at 4 °C, supporting the importance of temperature control in postharvest and produce processing environments. PMID:27052705

  10. Perspectives on super-shedding of Escherichia coli O157:H7 by cattle.

    PubMed

    Munns, Krysty D; Selinger, L Brent; Stanford, Kim; Guan, Leluo; Callaway, Todd R; McAllister, Tim A

    2015-02-01

    Escherichia coli O157:H7 is a foodborne pathogen that causes illness in humans worldwide. Cattle are the primary reservoir of this bacterium, with the concentration and frequency of E. coli O157:H7 shedding varying greatly among individuals. The term "super-shedder" has been applied to cattle that shed concentrations of E. coli O157:H7 ≥ 10⁴ colony-forming units/g feces. Super-shedders have been reported to have a substantial impact on the prevalence and transmission of E. coli O157:H7 in the environment. The specific factors responsible for super-shedding are unknown, but are presumably mediated by characteristics of the bacterium, animal host, and environment. Super-shedding is sporadic and inconsistent, suggesting that biofilms of E. coli O157:H7 colonizing the intestinal epithelium in cattle are intermittently released into feces. Phenotypic and genotypic differences have been noted in E. coli O157:H7 recovered from super-shedders as compared to low-shedding cattle, including differences in phage type (PT21/28), carbon utilization, degree of clonal relatedness, tir polymorphisms, and differences in the presence of stx2a and stx2c, as well as antiterminator Q gene alleles. There is also some evidence to support that the native fecal microbiome is distinct between super-shedders and low-shedders and that low-shedders have higher levels of lytic phage within feces. Consequently, conditions within the host may determine whether E. coli O157:H7 can proliferate sufficiently for the host to obtain super-shedding status. Targeting super-shedders for mitigation of E. coli O157:H7 has been proposed as a means of reducing the incidence and spread of this pathogen to the environment. If super-shedders could be easily identified, strategies such as bacteriophage therapy, probiotics, vaccination, or dietary inclusion of plant secondary compounds could be specifically targeted at this subpopulation. Evidence that super-shedder isolates share a commonality with isolates

  11. Use of Clustered Regularly Interspaced Short Palindromic Repeat Sequence Polymorphisms for Specific Detection of Enterohemorrhagic Escherichia coli Strains of Serotypes O26:H11, O45:H2, O103:H2, O111:H8, O121:H19, O145:H28, and O157:H7 by Real-Time PCR

    PubMed Central

    Delannoy, Sabine; Beutin, Lothar

    2012-01-01

    We explored the genetic diversity of the clustered regularly interspaced short palindromic repeat (CRISPR) regions of enterohemorrhagic Escherichia coli (EHEC) to design simplex real-time PCR assays for each of the seven most important EHEC serotypes worldwide. A panel of 958 E. coli strains investigated for their CRISPR loci by high-throughput real-time PCR showed that CRISPR polymorphisms in E. coli strongly correlated with both O:H serotypes and the presence of EHEC virulence factors (stx and eae genes). The CRISPR sequences chosen for simplex real-time PCR amplification of EHEC strains belonging to the top 7 EHEC serogroups differentiated clearly between EHEC and non-EHEC strains. Specificity estimates for the CRISPR PCR assays varied from 97.5% to 100%. Sensitivity estimates for the assays ranged from 95.7% to 100%. The assays targeting EHEC O145:H28, O103:H2, and O45:H2 displayed 100% sensitivity. The combined usage of two simplex PCR assays targeting different sequences of the O26 CRISPR locus allowed detection of EHEC O26:H11 with 100% sensitivity. By combining two simplex PCR assays targeting different sequences of the EHEC O157 CRISPR locus, EHEC O157:H7 was detected with 99.56% sensitivity. EHEC O111:H8 and EHEC O121:H19 were detected with 95.9% and 95.7% sensitivity, respectively. This study demonstrates that the identification of EHEC serotype-specific CRISPR sequences is more specific than the mere identification of O-antigen gene sequences, as is used in current PCR protocols for detection of EHEC strains. PMID:23035199

  12. Survival of Escherichia coli O157:H7 on Cattle Hides▿

    PubMed Central

    Arthur, Terrance M.; Nou, Xiangwu; Kalchayanand, Norasak; Bosilevac, Joseph M.; Wheeler, Tommy; Koohmaraie, Mohammad

    2011-01-01

    The objective of this study was to determine the time period that Escherichia coli O157:H7 survives on the hides of cattle. Extensive research has been conducted and is ongoing to identify and develop novel preharvest intervention strategies to reduce the presence of E. coli O157:H7 on live cattle and subsequent transfer to processed carcasses. If a reduction of E. coli O157:H7 levels in feces can be achieved through preharvest intervention, it is not known how long it would take for such reductions to be seen on the hide. In the study presented herein, three trials were conducted to follow E. coli O157:H7 hide prevalence over time. For each trial, 36 animals were housed in individual stanchions to minimize or prevent hide contamination events. Through prevalence determination and isolate genotyping with pulsed-field gel electrophoresis, survival of E. coli O157:H7 on the hides of live cattle was determined to be short lived, with an approximate duration of 9 days or less. The results of this study suggest that any preharvest interventions that are to be administered at the end of the finishing period will achieve maximum effect in reducing E. coli O157:H7 levels on cattle hides if given 9 days before the cattle are presented for processing. However, it should be noted that interventions reducing pathogen shedding would also contribute to decreasing hide contamination through lowering the contamination load of the processing plant lairage environment, regardless of the time of application. PMID:21398483

  13. Whole Genome Sequencing for Genomics-Guided Investigations of Escherichia coli O157:H7 Outbreaks

    PubMed Central

    Rusconi, Brigida; Sanjar, Fatemeh; Koenig, Sara S. K.; Mammel, Mark K.; Tarr, Phillip I.; Eppinger, Mark

    2016-01-01

    Multi isolate whole genome sequencing (WGS) and typing for outbreak investigations has become a reality in the post-genomics era. We applied this technology to strains from Escherichia coli O157:H7 outbreaks. These include isolates from seven North America outbreaks, as well as multiple isolates from the same patient and from different infected individuals in the same household. Customized high-resolution bioinformatics sequence typing strategies were developed to assess the core genome and mobilome plasticity. Sequence typing was performed using an in-house single nucleotide polymorphism (SNP) discovery and validation pipeline. Discriminatory power becomes of particular importance for the investigation of isolates from outbreaks in which macrogenomic techniques such as pulse-field gel electrophoresis or multiple locus variable number tandem repeat analysis do not differentiate closely related organisms. We also characterized differences in the phage inventory, allowing us to identify plasticity among outbreak strains that is not detectable at the core genome level. Our comprehensive analysis of the mobilome identified multiple plasmids that have not previously been associated with this lineage. Applied phylogenomics approaches provide strong molecular evidence for exceptionally little heterogeneity of strains within outbreaks and demonstrate the value of intra-cluster comparisons, rather than basing the analysis on archetypal reference strains. Next generation sequencing and whole genome typing strategies provide the technological foundation for genomic epidemiology outbreak investigation utilizing its significantly higher sample throughput, cost efficiency, and phylogenetic relatedness accuracy. These phylogenomics approaches have major public health relevance in translating information from the sequence-based survey to support timely and informed countermeasures. Polymorphisms identified in this work offer robust phylogenetic signals that index both short- and

  14. Whole Genome Sequencing for Genomics-Guided Investigations of Escherichia coli O157:H7 Outbreaks.

    PubMed

    Rusconi, Brigida; Sanjar, Fatemeh; Koenig, Sara S K; Mammel, Mark K; Tarr, Phillip I; Eppinger, Mark

    2016-01-01

    Multi isolate whole genome sequencing (WGS) and typing for outbreak investigations has become a reality in the post-genomics era. We applied this technology to strains from Escherichia coli O157:H7 outbreaks. These include isolates from seven North America outbreaks, as well as multiple isolates from the same patient and from different infected individuals in the same household. Customized high-resolution bioinformatics sequence typing strategies were developed to assess the core genome and mobilome plasticity. Sequence typing was performed using an in-house single nucleotide polymorphism (SNP) discovery and validation pipeline. Discriminatory power becomes of particular importance for the investigation of isolates from outbreaks in which macrogenomic techniques such as pulse-field gel electrophoresis or multiple locus variable number tandem repeat analysis do not differentiate closely related organisms. We also characterized differences in the phage inventory, allowing us to identify plasticity among outbreak strains that is not detectable at the core genome level. Our comprehensive analysis of the mobilome identified multiple plasmids that have not previously been associated with this lineage. Applied phylogenomics approaches provide strong molecular evidence for exceptionally little heterogeneity of strains within outbreaks and demonstrate the value of intra-cluster comparisons, rather than basing the analysis on archetypal reference strains. Next generation sequencing and whole genome typing strategies provide the technological foundation for genomic epidemiology outbreak investigation utilizing its significantly higher sample throughput, cost efficiency, and phylogenetic relatedness accuracy. These phylogenomics approaches have major public health relevance in translating information from the sequence-based survey to support timely and informed countermeasures. Polymorphisms identified in this work offer robust phylogenetic signals that index both short- and

  15. Rectoanal Junction Colonization of Feedlot Cattle by Escherichia coli O157:H7 and Its Association with Supershedders and Excretion Dynamics▿

    PubMed Central

    Cobbold, Rowland N.; Hancock, Dale D.; Rice, Daniel H.; Berg, Janice; Stilborn, Robert; Hovde, Carolyn J.; Besser, Thomas E.

    2007-01-01

    Feedlot cattle were observed for fecal excretion of and rectoanal junction (RAJ) colonization with Escherichia coli O157:H7 to identify potential “supershedders.” RAJ colonization and fecal excretion prevalences were correlated, and E. coli O157:H7 prevalences and counts were significantly greater for RAJ samples. Based on a comparison of RAJ and fecal ratios of E. coli O157:H7/E. coli counts, the RAJ appears to be preferentially colonized by the O157:H7 serotype. Five supershedders were identified based on persistent colonization with high concentrations of E. coli O157:H7. Cattle copenned with supershedders had significantly greater mean pen E. coli O157:H7 RAJ and fecal prevalences than noncopenned cattle. Cumulative fecal E. coli O157:H7 excretion was also significantly higher for pens housing a supershedder. E. coli O157:H7/E. coli count ratios were higher for supershedders than for other cattle, indicating greater proportional colonization. Pulsed-field gel electrophoresis analysis demonstrated that isolates from supershedders and copenned cattle were highly related. Cattle that remained negative for E. coli O157:H7 throughout sampling were five times more likely to have been in a pen that did not house a supershedder. The data from this study support an association between levels of fecal excretion of E. coli O157:H7 and RAJ colonization in pens of feedlot cattle and suggest that the presence of supershedders influences group-level excretion parameters. An improved understanding of individual and population transmission dynamics of E. coli O157:H7 can be used to develop preslaughter- and slaughter-level interventions that reduce contamination of the food chain. PMID:17220263

  16. Survival mechanism of Escherichia coli O157:H7 against combined treatment with acetic acid and sodium chloride.

    PubMed

    Lee, Sun-Young; Kang, Dong-Hyun

    2016-05-01

    The combination of salt and acid is commonly used in the production of many foods, including pickles and fermented foods. However, in our previous studies, the addition of salt significantly reduced the inhibitory effect of acetic acid on Escherichia coli O157:H7 in laboratory media and pickled cucumbers. Therefore, this study was conducted to determine the mechanism by which salt confers resistance against acetic acid in E. coli O157:H7. The addition of high concentrations (up to 9% or 15% [w/v]) of salt increased the resistance of E. coli O157:H7 to acetic acid treatment. Combined treatment with acetic acid and salt showed varying results among different bacterial strains (an antagonistic effect for E. coli O157:H7 and Shigella and a synergistic effect for Listeria monocytogenes and Staphylococcus aureus). The addition of salt increased the cytoplasmic pH of E. coli O157:H7, but decreased the cytoplasmic pH of L. monocytogenes and S. aureus on treatment with acetic acid. Therefore, the addition of salt increases the acid resistance of E. coli O157:H7 possibly by increasing its acid resistance response and consequently preventing the acidification of its cytoplasm by organic acids. PMID:26742620

  17. Recovery and Detection of Escherichia coli O157:H7 in Surface Water, Using Ultrafiltration and Real-Time PCR▿

    PubMed Central

    Mull, Bonnie; Hill, Vincent R.

    2009-01-01

    Enterohemorrhagic Escherichia coli O157:H7 (EHEC O157:H7) outbreaks have revealed the need for improved analytical techniques for environmental samples. Ultrafiltration (UF) is increasingly recognized as an effective procedure for concentrating and recovering microbes from large volumes of water and treated wastewater. This study describes the application of hollow-fiber UF as the primary step for concentrating EHEC O157:H7 seeded into 40-liter samples of surface water, followed by an established culture/immunomagnetic-separation (IMS) method and a suite of real-time PCR assays. Three TaqMan assays were used to detect the stx1, stx2, and rfbE gene targets. The results from this study indicate that approximately 50 EHEC O157:H7 cells can be consistently recovered from a 40-liter surface water sample and detected by culture and real-time PCR. Centrifugation was investigated and shown to be a viable alternative to membrane filtration in the secondary culture/IMS step when water quality limits the volume of water that can be processed by a filter. Using multiple PCR assay sets to detect rfbE, stx1, and stx2 genes allowed for specific detection of EHEC O157:H7 from strains that do not possess all three genes. The reported sample collection and analysis procedure should be a sensitive and effective tool for detecting EHEC O157:H7 in response to outbreaks of disease associated with contaminated water. PMID:19363065

  18. Detecting and Genotyping Escherichia coli O157:H7 using multiplexed PCR and nucleic acid microarrays

    SciTech Connect

    Call, Douglas R.; Brockman, Fred J. ); Chandler, Darrell P.

    2000-12-01

    Rapid detection and characterization of food borne pathogens such as Escherichia coli O157:H7 is crucial for epidemiological investigations and food safety surveillance. As an alternative to conventional technologies, we examined the sensitivity and specificity of nucleic acid microarrays for detecting and genotyping E. coli O157:H7. The array was composed of oligonucleotide probes (25-30 mer) complementary to four virulence loci (intimin, Shiga-like toxins I and II, and hemolysin A). Target DNA was amplified from whole cells or from purified DNA via single or multiplexed polymerase chain reaction (PCR), and PCR products were hybridized to the array without further modification or purification. The array was 32-fold more sensitive than gel electrophoresis and capable of detecting amplification products from < 1 cell equivalent of genomic DNA (1 fg). Immunomagnetic capture, PCR and a microarray were subsequently used to detect 55 CFU ml-1 (E. coli O157:H7) from chicken rinsate without the aid of pre-enrichment. Four isolates of E. coli O157:H7 and one isolate of O91:H2, for which genotypic data were available, were unambiguously genotyped with this array. Glass based microarrays are relatively simple to construct and provide a rapid and sensitive means to detect multiplexed PCR products and the system is amenable to automation.

  19. The role of heightened surveillance in an outbreak of Escherichia coli O157.H7.

    PubMed Central

    Roberts, C. L.; Mshar, P. A.; Cartter, M. L.; Hadler, J. L.; Sosin, D. M.; Hayes, P. S.; Barrett, T. J.

    1995-01-01

    After instituting laboratory screening for Escherichia coli O157.H7, a Connecticut hospital isolated the organism from four persons in September 1993. As a result, an outbreak of E. coli O157.H7 associated with a country club was detected. The club had served hamburger from the same shipment at two picnics. Attendees of two picnics were interviewed, stool cultures were obtained from symptomatic persons, and the remaining hamburger was cultured. Twenty (22%) of 89 persons who ate hamburger became ill, compared with 1 of 60 who did not eat hamburger (relative risk = 13.5, 95% confidence interval 3.2-56.3). Among persons who ate hamburgers, illness was strongly associated with eating hamburger that was not thoroughly cooked (P < 0.001). All 20 samples from 5 remaining boxes of patties yielded E. coli O157.H7. Isolates from hamburger and case-patients were indistinguishable by pulsed-field gel electrophoresis. Heightened surveillance can rapidly identify outbreaks and may mitigate their impact. However, continued review of food safety issues is necessary if E. coli O157.H7 outbreaks are to be prevented. PMID:8557076

  20. Detecting and genotyping Escherichia coli O157:H7 using multiplexed PCR and nucleic acid microarrays

    SciTech Connect

    Call, Douglas R.; Brockman, Fred J.; Chandler, Darrell P.

    2001-07-05

    Rapid detection and characterization of food borne pathogens such as Escherichia coli O157:H7 is crucial for epidemiological investigations and food safety surveillance. As an alternative to conventional technologies, we examined the sensitivity and specificity of nucleic acid microarrays for detecting and genotyping E. coli O157:H7. The array was composed of oligonucleotide probes (25-30 mer) complementary to four virulence loci (intimin, Shiga-like toxins I and II, and hemolysin A). Target DNA was amplified from whole cells or from purified DNA via single or multiplexed polymerase chain reaction (PCR), and PCR products were hybridized to the array without further modification or purification. The array was 32-fold more sensitive than gel electrophoresis and capable of detecting amplification products from < 1 cell equivalent of genomic DNA (1 fg). Immunomagnetic capture, PCR and a microarray were subsequently used to detect 55 CFUs ml-1 (E. coli O157:H7) from chicken rinsate without the aid of pre-enrichment. Four isolates of E. coli O157:H7 and one isolate of O91:H2, for which genotypic data were available, were unambiguously genotyped with this array. Glass based microarrays are relatively simple to construct and provide a rapid and sensitive means to detect multiplexed PCR products and the system is amenable to automation.

  1. Inhibition of water absorption and selective damage to human colonic mucosa induced by Shiga toxin-2 are enhanced by Escherichia coli O157:H7 infection.

    PubMed

    Albanese, Adriana; Gerhardt, Elizabeth; García, Hugo; Amigo, Natalia; Cataldi, Angel; Zotta, Elsa; Ibarra, Cristina

    2015-05-01

    Shiga toxin-producing Escherichia coli (STEC) strains are responsible for a variety of clinical syndromes including bloody and non-bloody diarrhea, hemorrhagic colitis, and hemolytic uremic syndrome (HUS). Although multiple serotypes of STEC have been isolated from hemorrhagic colitis cases, E. coli O157:H7 is by far the most prevalent serotype associated with HUS. Shiga toxin is the major virulence factor of E. coli O157:H7 and is responsible for the more severe symptoms of the infection. However, the mechanisms involved in the pathogenesis of diarrhea mediated by Stx2 are not well known. In this study, we have determined the effects of E. coli O157:H7 strain 125/99 wild type (wt) on the human colonic mucosa mounted in an Ussing chamber. In response to 125/99wt, an inhibition of water absorption across human colonic mucosa was observed. Histological sections showed severe necrosis with detachment of the surface epithelium, mononuclear inflammatory infiltrate and loss of goblet cells after 1h of incubation with 125/99wt. These alterations were not observed with the isogenic mutant strain lacking stx2 or with the filter-sterilized culture supernatant from the 125/99wt strain. These results indicate that the cell damages in human colon are induced by Stx2, and that Stx2 production is increased by the interaction with bacterial cells. Identification of host cell-derived factors responsible for increasing Stx2 can lead to new strategies for modulating STEC infections. PMID:25794836

  2. CsgA Production by Escherichia coli O157:H7 Alters Attachment to Abiotic Surfaces in Some Growth Environments ▿

    PubMed Central

    Goulter-Thorsen, R. M.; Taran, E.; Gentle, I. R.; Gobius, K. S.; Dykes, G. A.

    2011-01-01

    The role of curli expression in attachment of Escherichia coli O157:H7 to glass, Teflon, and stainless steel (SS) was investigated through the creation of csgA knockout mutants in two isolates of E. coli O157:H7. Attachment assays using epifluorescence microscopy and measurements of the force of adhesion of bacterial cells to the substrates using atomic force microscopy (AFM) force mapping were used to determine differences in attachment between wild-type (wt) and csgA-negative (ΔcsgA) strains following growth in four different media. The hydrophobicity of the cells was determined using contact angle measurements (CAM) and bacterial adhesion to hydrocarbons (BATH). The attachment assay results indicated that ΔcsgA strains attached to glass, Teflon, and SS surfaces in significantly different numbers than their wt counterparts in a growth medium-dependent fashion (P < 0.05). However, no clear correlation was seen between attachment numbers, surface type, or growth medium. No correlation was seen between BATH and CAM results (R2 < 0.70). Hydrophobicity differed between the wt and ΔcsgA in some cases in a growth medium- and method-dependent fashion (P < 0.05). AFM force mapping revealed no significant difference in the forces of adhesion to glass and SS surfaces between wt and ΔcsgA strains (P > 0.05) but a significantly greater force of adhesion to Teflon for one of the two wt strains than for its ΔcsgA counterpart (P < 0.05). This study shows that CsgA production by E. coli O157:H7 may alter attachment behavior in some environments; however, further investigation is required in order to determine the exact relationship between CsgA production and attachment to abiotic surfaces. PMID:21856839

  3. Prevalence and concentration of Verotoxigenic Escherichia coli O157:H7 in adult sheep at slaughter from Italy.

    PubMed

    Franco, A; Lovari, S; Cordaro, G; Di Matteo, P; Sorbara, L; Iurescia, M; Donati, V; Buccella, C; Battisti, A

    2009-06-01

    A 1-year study on the animal-level prevalence and concentration of Escherichia coli O157 in adult sheep at slaughter was performed, to collect qualitative and quantitative information on the diffusion of the pathogen in adult sheep from Italy. A total 533 samples were collected, with a similar distribution in the four seasons. For prevalence estimates, a simple random sampling technique was used. An immuno-magnetic separation technique was used for sample screening, with enumeration of the pathogen in positive samples, along with molecular and serological identification of isolates. An overall prevalence of 7.1% (38/ 533, 95% CI 4.9-9.3%) was observed for fully virulent E. coli O157. A wide interval of VTEC O157 per gram was observed (< 100 to 6 x 10(5) CFU g(-1)), with 28.9% (11/38) of positive samples > or = 1 x 10(3) CFU g(-1), set as the threshold for those animals defined 'active shedders' for the purpose of the study. Eight per cent (3/38) of animals shed > 1 x 10(4) g(-1) VTEC O157, which represents > 96% of the total VTEC O157 bacteria cultured from all animals tested. The prevalence estimate of active shedders was therefore 2.1% (95% CI 0.9-3.3%). Most (34/38, 89.5%) of the positive animals were found in summer (July-September). Prevalence and concentrations of virulent VTEC O157 obtained in this study contribute to the demonstration that adult sheep represent a relevant source of environmental contamination from virulent VTEC O157, as well as a source of VTEC O157 contamination for food of ovine origin (meat and dairy products), especially during warm months. PMID:18990195

  4. Validation of the ANSR(®) E. coli O157:H7 Method for Detection of E. coli O157:H7.

    PubMed

    Viator, Ryan; Alles, Susan; Le, Quynh-Nhi; Hosking, Edan; Meister, Evan; Pinkava, Lisa; Tovar, Eric; Mozola, Mark; Rice, Jennifer

    2016-05-01

    A performance validation of the ANSR(®) for E. coli O157:H7 method was conducted in selected food matrixes. This assay uses selective nicking enzyme amplification technology to amplify target genes. Samples are enriched for 12-24 h and then lysed. The assay is completed within 40 min using real-time detection in a combination incubator/fluorescence detector and software. When 44 distinct strains of Escherichia coli O157:H7 and 6 strains of E. coli O157:NM were tested for inclusivity, all 50 strains produced positive results. In exclusivity testing, 57 strains representing 33 species of closely related Gram-negative bacteria belonging to the Enterobacteriaceae family, including 11 non-H7 O157 strains and shiga toxin-producing E. coli other than O157:H7, were evaluated. All 57 nontarget strains generated negative ANSR assay results. Using 80% lean ground beef and beef trim (approximately 20% fat), ANSR method performance was compared to the U.S. Department of Agriculture, Food Safety and Inspection Service Microbiology Laboratory Guidebook reference culture procedure. ANSR performance with baby spinach and sprout irrigation water was measured against the U.S. Food and Drug Administration Bacteriological Analytical Manual reference method. ANSR method performance was not statistically different to that of the reference methods using two different enrichment options. For ground beef and beef trim, the standard enrichment in modified Tryptone Soya Broth can be analyzed using the ANSR assay with a 1:10 dilution of the enrichment in phosphate-buffered saline and produces equivalent results to the reference method. Additionally, in most matrixes tested (exception is spinach which required 24 h enrichment) the assay offers great efficiency and flexibility over the reference method with a 12-24 h single-step enrichment. Equivalent results were observed at both time points (12 and 24 h) to reference methods. Small changes to the assay parameters minimally affected ANSR

  5. The utility of multiple molecular methods including whole genome sequencing as tools to differentiate Escherichia coli O157:H7 outbreaks.

    PubMed

    Berenger, Byron M; Berry, Chrystal; Peterson, Trevor; Fach, Patrick; Delannoy, Sabine; Li, Vincent; Tschetter, Lorelee; Nadon, Celine; Honish, Lance; Louie, Marie; Chui, Linda

    2015-01-01

    A standardised method for determining Escherichia coli O157:H7 strain relatedness using whole genome sequencing or virulence gene profiling is not yet established. We sought to assess the capacity of either high-throughput polymerase chain reaction (PCR) of 49 virulence genes, core-genome single nt variants (SNVs) or k-mer clustering to discriminate between outbreak-associated and sporadic E. coli O157:H7 isolates. Three outbreaks and multiple sporadic isolates from the province of Alberta, Canada were included in the study. Two of the outbreaks occurred concurrently in 2014 and one occurred in 2012. Pulsed-field gel electrophoresis (PFGE) and multilocus variable-number tandem repeat analysis (MLVA) were employed as comparator typing methods. The virulence gene profiles of isolates from the 2012 and 2014 Alberta outbreak events and contemporary sporadic isolates were mostly identical; therefore the set of virulence genes chosen in this study were not discriminatory enough to distinguish between outbreak clusters. Concordant with PFGE and MLVA results, core genome SNV and k-mer phylogenies clustered isolates from the 2012 and 2014 outbreaks as distinct events. k-mer phylogenies demonstrated increased discriminatory power compared with core SNV phylogenies. Prior to the widespread implementation of whole genome sequencing for routine public health use, issues surrounding cost, technical expertise, software standardisation, and data sharing/comparisons must be addressed. PMID:26625187

  6. Effect of high pressure processing on the survival of Shiga toxin-producing Escherichia coli (Big Six vs. O157:H7) in ground beef.

    PubMed

    Hsu, HsinYun; Sheen, Shiowshuh; Sites, Joseph; Cassidy, Jennifer; Scullen, Butch; Sommers, Christopher

    2015-06-01

    High pressure processing (HPP) is a safe and effective technology for improving food safety. Non-O157:H7 Shiga Toxin-producing Escherichia coli (STEC) have been increasingly implicated in foodborne illness outbreaks and recalls, and the USDA Food Safety Inspection Service (FSIS) has designated them as adulterants in meat (e.g. ground beef). In this study we compared the inactivation of multi-isolate cocktails of E. coli O157:H7 versus the non-O157:H7 STEC "Big Six" (i.e. O26, O45, O103, O111, O121, and O145) in ground beef (83% lean) using HPP at refrigeration temperature (4-7 °C). A >5-log CFU/g inactivation of both the Big Six and O157:H7 cocktails were observed at 450 MPa for 15 min. In general, the Big Six cocktail was found more sensitive to pressure stress (p < 0.05). In contrast, HPP treatment at 250 MPa (30 min) inactivated only 2.3 log of the Big Six versus 1.0 log of O157:H7. HPP treatment at 350 MPa (30 min) inactivated 4.7 log of the Big Six vs. 3.2 log of O157:H7. Multiple-cycle HPP cycles (250 or 350 MPa, three 5 min treatments) did not result in a 5 log reduction of the non-O157:H7 or O157:H7 STEC. Our results indicate that HPP inactivation parameters which are effective for O157:H7 STEC can be used for the non-O157:H7 Big Six isolates in ground beef. PMID:25790984

  7. Sensitive detection of E. coli O157:H7

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Introduction: Escherichia coli O157:H7, the most common serotype of enterohemorrhagic E. coli, is responsible for numerous food- and water-borne infections worldwide. Conventional culture-based methods for detection of E. coli O157:H7 in foods and water sources are time-consuming, and results can be...

  8. The endophytic lifestyle of Escherichia coli O157:H7: quantification and internal localization in roots.

    PubMed

    Wright, Kathryn M; Chapman, Sean; McGeachy, Kara; Humphris, Sonia; Campbell, Emma; Toth, Ian K; Holden, Nicola J

    2013-04-01

    The foodborne pathogen Escherichia coli O157:H7 is increasingly associated with fresh produce (fruit and vegetables). Bacterial colonization of fresh produce plants can occur to high levels on the external tissue but bacteria have also been detected within plant tissue. However, questions remain about the extent of internalization, its molecular basis, and internal location of the bacteria. We have determined the extent of internalization of E. coli O157:H7 in live spinach and lettuce plants and used high-resolution microscopy to examine colony formation in roots and pathways to internalization. E. coli O157:H7 was found within internal tissue of both produce species. Colonization occurred within the apoplast between plant cells. Furthermore, colonies were detected inside the cell wall of epidermal and cortical cells of spinach and Nicotiana benthamiana roots. Internal colonization of epidermal cells resembled that of the phytopathogen Pectobacterium atrosepticum on potato. In contrast, only sporadic cells of the laboratory strain of E. coli K-12 were found on spinach, with no internal bacteria evident. The data extend previous findings that internal colonization of plants appears to be limited to a specific group of plant-interacting bacteria, including E. coli O157:H7, and demonstrates its ability to invade the cells of living plants. PMID:23506361

  9. Acid and alcohol tolerance of Escherichia coli O157:H7 in pulque, a typical Mexican beverage.

    PubMed

    Gómez-Aldapa, Carlos A; Díaz-Cruz, Claudio A; Villarruel-López, Angelica; Del Refugio Torres-Vitela, M; Rangel-Vargas, Esmeralda; Castro-Rosas, Javier

    2012-03-01

    Pulque is a traditional Mexican fermented alcoholic beverage produced from the nectar of maguey agave plants. No data exist on the behavior of Escherichia coli O157:H7 in agave nectar and pulque. An initial trial was done of the behavior of E. coli O157:H7 during fermentation of nectar from a single producer, a nectar mixture from different producers and "seed" pulque. A second trial simulating artisanal pulque production was done by contaminating fresh nectar with a cocktail of three E. coli O157:H7 strains, storing at 16 ° and 22 °C for 14 h, adding seed pulque and fermenting until pulque was formed. A third trial used pulque from the second trial stored at 22 °C as seed to ferment fresh nectar at 22 °C for 48 h (fermentation cycle). This procedure was repeated for an additional two fermentation cycles. During incubation at 16 ° or 22 °C in the first trial, the E. coli O157:H7 strains multiplied in both the single producer nectar and nectar mixture, reaching maximum concentration at 12h. E. coli O157:H7 cell concentration then decreased slowly, although it survived at least 72 h in both fermented nectars. E. coli O157:H7 did not multiply in the seed pulque but did survive at least 72 h. In the second trial, the numbers of E. coli O157:H7 increased approximately 1.5 log CFU/ml at 22 °C and 1.2 log CFU/ml at 16 °C after 14 h. After seed pulque was added, E. coli O157:H7 concentration decreased to approximately 2 log CFU/ml, and then remained constant until pulque was produced. In the third trial, the E. coli O157:H7 cells multiplied and survived during at least three nectar fermentation cycles. The results suggest that E. coli O157:H7 can develop acid and alcohol tolerance in pulque, and constitutes a public health risk for pulque consumers. PMID:22240059

  10. A multistate outbreak of Escherichia coli O157:H7 infections linked to alfalfa sprouts grown from contaminated seeds.

    PubMed Central

    Breuer, T.; Benkel, D. H.; Shapiro, R. L.; Hall, W. N.; Winnett, M. M.; Linn, M. J.; Neimann, J.; Barrett, T. J.; Dietrich, S.; Downes, F. P.; Toney, D. M.; Pearson, J. L.; Rolka, H.; Slutsker, L.; Griffin, P. M.

    2001-01-01

    A multistate outbreak of Escherichia coli O157:H7 infections occurred in the United States in June and July 1997. Two concurrent outbreaks were investigated through independent case-control studies in Michigan and Virginia and by subtyping isolates with pulsed-field gel electrophoresis (PFGE). Isolates from 85 persons were indistinguishable by PFGE. Alfalfa sprouts were the only exposure associated with E. coli O157:H7 infection in both Michigan and Virginia. Seeds used for sprouting were traced back to one common lot harvested in Idaho. New subtyping tools such as PFGE used in this investigation are essential to link isolated infections to a single outbreak. PMID:11747724

  11. Insertion/deletion-based approach for the detection of Escherichia coli O157:H7 in freshwater environments.

    PubMed

    Wong, Shirley Y; Paschos, Athanasios; Gupta, Radhey S; Schellhorn, Herb E

    2014-10-01

    Enterohemorrhagic Escherichia coli O157:H7 is responsible for many outbreaks of gastrointestinal illness and hemolytic uremic syndrome worldwide. Monitoring this pathogen in food and water supplies is an important public health issue. Highly conserved genetic markers, which are characteristic for specific strains, can provide direct identification of target pathogens. In this study, we examined a new detection strategy for pathogenic strains of E. coli O157:H7 serotype based on a conserved signature insertion/deletion (CSI) located in the ybiX gene using TaqMan-probe-based quantitative PCR (qPCR). The qPCR assay was linear from 1.0 × 10(2) to 1.0 × 10(7) genome copies and was specific to O157:H7 when tested against a panel of 15 non-O157:H7 E. coli. The assay also maintained detection sensitivity in the presence of competing E. coli K-12, heterologous nontarget DNA spiked in at a 1000-fold and 800-fold excess of target DNA, respectively, demonstrating the assay's ability to detect E. coli O157:H7 in the presence of high levels of background DNA. This study thus validates the use of strain-specific CSIs as a new class of diagnostic marker for pathogen detection. PMID:25166281

  12. Serological cross-reactions between Escherichia coli O157 and other species of the genus Escherichia.

    PubMed

    Rice, E W; Sowers, E G; Johnson, C H; Dunnigan, M E; Strockbine, N A; Edberg, S C

    1992-05-01

    The antigenic relatedness of Escherichia coli O157 and four sorbitol-negative species of the genus Escherichia was examined. Isolates of Escherichia hermannii, E. fergusonii, E. vulneris, and E. blattae were tested in the tube agglutination assay by using polyclonal antisera and in the slide agglutination assay by using latex reagents. Only four isolates (17%) of E. hermannii exhibited serological cross-reactivity. PMID:1583138

  13. Serological cross-reactions between Escherichia coli O157 and other species of the genus Escherichia.

    PubMed Central

    Rice, E W; Sowers, E G; Johnson, C H; Dunnigan, M E; Strockbine, N A; Edberg, S C

    1992-01-01

    The antigenic relatedness of Escherichia coli O157 and four sorbitol-negative species of the genus Escherichia was examined. Isolates of Escherichia hermannii, E. fergusonii, E. vulneris, and E. blattae were tested in the tube agglutination assay by using polyclonal antisera and in the slide agglutination assay by using latex reagents. Only four isolates (17%) of E. hermannii exhibited serological cross-reactivity. PMID:1583138

  14. Nissui Glucose Fermentative Gram-Negative Rod Identification System EB-20 Gives a Unique Profile for Typical Non-Sorbitol-Fermenting Escherichia coli O157:H7

    PubMed Central

    Kodaka, H.; Uesaka, Y.; Kashitani, F.

    2004-01-01

    The 98 non-sorbitol-fermenting (NSF) Escherichia coli O157:H7 strains identified on a Nissui glucose fermentative gram-negative rod identification system (EB-20) gave a unique biochemical profile number that was not detected in 85 pathogenic and 13 nonpathogenic E. coli strains. Thus, EB-20 is useful for the identification of NSF E. coli O157:H7 and provides a simple, cost-effective, and reliable tool for clinical laboratories. PMID:14715777

  15. Potential Uptake of Escherichia coli O157:H7 from Organic Manure into Crisphead Lettuce

    PubMed Central

    Johannessen, Gro S.; Bengtsson, Gunnar B.; Heier, Berit T.; Bredholt, Sylvia; Wasteson, Yngvild; Rørvik, Liv Marit

    2005-01-01

    To investigate the potential transfer of Escherichia coli O157:H7 from contaminated manure to fresh produce, lettuce seedlings were transplanted into soil fertilized with bovine manure which had been inoculated with approximately 104 CFU g−1 E. coli O157:H7. The lettuce was grown for approximately 50 days in beds in climate-controlled rooms in a greenhouse. As the bacterium was not detected in the edible parts of the lettuce, the outer leaves of the lettuce, or the lettuce roots at harvest it was concluded that transmission of E. coli O157:H7 from contaminated soil to lettuce did not occur. The pathogen persisted in the soil for at least 8 weeks after fertilizing but was not detected after 12 weeks. Indigenous E. coli was detected only sporadically on the lettuce at harvest, and enterococci were not detected at all. The numbers of enterococci declined more rapidly than those of E. coli in the soil. Pseudomonas fluorescens, which inhibited growth of E. coli O157:H7 in vitro, was isolated from the rhizosphere. PMID:15870303

  16. Protozoan Predation of Escherichia coli O157:H7 Is Unaffected by the Carriage of Shiga Toxin-Encoding Bacteriophages.

    PubMed

    Schmidt, Carrie E; Shringi, Smriti; Besser, Thomas E

    2016-01-01

    Escherichia coli O157:H7 is a food-borne bacterium that causes hemorrhagic diarrhea and hemolytic uremic syndrome in humans. While cattle are a known source of E. coli O157:H7 exposure resulting in human infection, environmental reservoirs may also be important sources of infection for both cattle and humans. Bacteriophage-encoded Shiga toxins (Stx) carried by E. coli O157:H7 may provide a selective advantage for survival of these bacteria in the environment, possibly through their toxic effects on grazing protozoa. To determine Stx effects on protozoan grazing, we co-cultured Paramecium caudatum, a common ciliate protozoon in cattle water sources, with multiple strains of Shiga-toxigenic E. coli O157:H7 and non-Shiga toxigenic cattle commensal E. coli. Over three days at ambient laboratory temperature, P. caudatum consistently reduced both E. coli O157:H7 and non-Shiga toxigenic E. coli populations by 1-3 log cfu. Furthermore, a wild-type strain of Shiga-toxigenic E. coli O157:H7 (EDL933) and isogenic mutants lacking the A subunit of Stx 2a, the entire Stx 2a-encoding bacteriophage, and/or the entire Stx 1-encoding bacteriophage were grazed with similar efficacy by both P. caudatum and Tetrahymena pyriformis (another ciliate protozoon). Therefore, our data provided no evidence of a protective effect of either Stx or the products of other bacteriophage genes on protozoan predation of E. coli. Further research is necessary to determine if the grazing activity of naturally-occurring protozoa in cattle water troughs can serve to decrease cattle exposure to E. coli O157:H7 and other Shiga-toxigenic E. coli. PMID:26824472

  17. Protozoan Predation of Escherichia coli O157:H7 Is Unaffected by the Carriage of Shiga Toxin-Encoding Bacteriophages

    PubMed Central

    Schmidt, Carrie E.; Shringi, Smriti; Besser, Thomas E.

    2016-01-01

    Escherichia coli O157:H7 is a food-borne bacterium that causes hemorrhagic diarrhea and hemolytic uremic syndrome in humans. While cattle are a known source of E. coli O157:H7 exposure resulting in human infection, environmental reservoirs may also be important sources of infection for both cattle and humans. Bacteriophage-encoded Shiga toxins (Stx) carried by E. coli O157:H7 may provide a selective advantage for survival of these bacteria in the environment, possibly through their toxic effects on grazing protozoa. To determine Stx effects on protozoan grazing, we co-cultured Paramecium caudatum, a common ciliate protozoon in cattle water sources, with multiple strains of Shiga-toxigenic E. coli O157:H7 and non-Shiga toxigenic cattle commensal E. coli. Over three days at ambient laboratory temperature, P. caudatum consistently reduced both E. coli O157:H7 and non-Shiga toxigenic E. coli populations by 1–3 log cfu. Furthermore, a wild-type strain of Shiga-toxigenic E. coli O157:H7 (EDL933) and isogenic mutants lacking the A subunit of Stx 2a, the entire Stx 2a-encoding bacteriophage, and/or the entire Stx 1-encoding bacteriophage were grazed with similar efficacy by both P. caudatum and Tetrahymena pyriformis (another ciliate protozoon). Therefore, our data provided no evidence of a protective effect of either Stx or the products of other bacteriophage genes on protozoan predation of E. coli. Further research is necessary to determine if the grazing activity of naturally-occurring protozoa in cattle water troughs can serve to decrease cattle exposure to E. coli O157:H7 and other Shiga-toxigenic E. coli. PMID:26824472

  18. Microarray based comparison of two Escherichia coli O157:H7 lineages

    PubMed Central

    Dowd, Scot E; Ishizaki, Hiroshi

    2006-01-01

    Background Previous research has identified the potential for the existence of two separate lineages of Escherichia coli O157:H7. Clinical isolates tended to cluster primarily within one of these two lineages. To determine if there are virulence related genes differentially expressed between the two lineages we chose to utilize microarray technology to perform an initial screening. Results Using a 610 gene microarray, designed against the E. coli O157 EDL 933 transcriptome, targeting primarily virulence systems, we chose 3 representative Lineage I isolates (LI groups mostly clinical isolates) and 3 representative Lineage II isolates (LII groups mostly bovine isolates). Using standard dye swap experimental designs, statistically different expression (P < 0.05) of 73 genes between the two lineages was revealed. Result highlights indicate that under in vitro anaerobic growth conditions, there is up-regulation of stx2b, ureD, curli (csgAFEG), and stress related genes (hslJ, cspG, ibpB, ibpA) in Lineage I, which may contribute to enhanced virulence or transmission potential. Lineage II exhibits significant up-regulation of type III secretion apparatus, LPS, and flagella related transcripts. Conclusion These results give insight into comparative regulation of virulence genes as well as providing directions for future research. Ultimately, evaluating the expression of key virulence factors among different E. coli O157 isolates has inherent value and the interpretation of such expression data will continue to evolve as our understanding of virulence, pathogenesis and transmission improves. PMID:16539702

  19. The Escherichia coli O157 Flagellar Regulatory Gene flhC and Not the Flagellin Gene fliC Impacts Colonization of Cattle

    PubMed Central

    Dobbin, Heather S.; Hovde, Carolyn J.; Williams, Christopher J.; Minnich, Scott A.

    2006-01-01

    A virulent European Escherichia coli O157:H− isolate is nonmotile due to a 12-bp deletion in the flagellar regulatory gene flhC. To investigate the contribution of flhC in the relationship between E. coli O157:H7 and cattle, we constructed a similar flhC regulatory mutant in the well-characterized strain ATCC 43894. There was no difference in the growth rate between the wild type and this regulatory mutant, but phenotypic arrays showed substrate utilization differences. Survival in the bovine gastrointestinal tract and colonization of the rectoanal junction mucosa were assessed. Mixtures of both strains were given orally or rectally to steers or administered into the rumen of cattle dually cannulated at the rumen and duodenum. One day post-oral dose, most rectal/fecal isolates (74%) were the regulatory mutant, but by 3 days post-oral dose and throughout the 42-day experiment, ≥80% of the isolates were wild type. Among steers given a rectal application of both strains, wild-type isolates were the majority of isolates recovered on all days. The regulatory mutant survived better than the wild type in both the rumen and duodenum. To test the role of motility, a filament mutant (ΔfliC) was constructed and similar cattle experiments were performed. On all days post-oral dose, the majority of isolates (64% to 98%) were the filament mutant. In contrast, both strains were recovered equally post-rectal application. Thus, the regulatory mutant survived passage through the bovine gastrointestinal tract better than the wild type but failed to efficiently colonize cattle, and the requirement of flhC for colonization was not dependent on a functional flagellum. PMID:16622228

  20. Shiga toxin-producing Escherichia coli in Central Greece: prevalence and virulence genes of O157:H7 and non-O157 in animal feces, vegetables, and humans.

    PubMed

    Pinaka, O; Pournaras, S; Mouchtouri, V; Plakokefalos, E; Katsiaflaka, A; Kolokythopoulou, F; Barboutsi, E; Bitsolas, N; Hadjichristodoulou, C

    2013-11-01

    In Greece, Shiga toxin-producing Escherichia coli (STEC) have only been sporadically reported. The objective of this study was to estimate the prevalence of STEC and Escherichia coli O157:H7 in farm animals, vegetables, and humans in Greece. A total number of 1,010 fecal samples were collected from farm animals (sheep, goats, cattle, chickens, pigs), 667 diarrheal samples from humans, and 60 from vegetables, which were cultured in specific media for STEC isolates. Enzyme-linked immunosorbent assay (ELISA) was used to detect toxin-producing colonies, which, subsequently, were subjected to a multiplex polymerase chain reaction (PCR) for stx1, stx2, eae, rfbE O157, and fliC h7 genes. Eighty isolates (7.9 %) from animal samples were found to produce Shiga toxin by ELISA, while by PCR, O157 STEC isolates were detected from 8 (0.8 %) samples and non-O157 STEC isolates from 43 (4.2 %) samples. STEC isolates were recovered mainly from sheep and goats, rarely from cattle, and not from pigs and chickens, suggesting that small ruminants constitute a potential risk for human infections. However, only three human specimens (0.4 %) were positive for the detection of Shiga toxins and all were PCR-negative. Similarly, all 60 vegetable samples were negative for toxin production and for toxin genes, but three samples (two roman rockets and one spinach) were positive by PCR for rfbE O157 and fliC h7 genes. These findings indicate that sheep, goats, cattle, and leafy vegetables can be a reservoir of STEC and Escherichia coli O157:H7 isolates in Greece, which are still rarely detected among humans. PMID:23677425

  1. Influence of the Plant Defense Response to Escherichia coli O157:H7 Cell Surface Structures on Survival of That Enteric Pathogen on Plant Surfaces

    PubMed Central

    Seo, Suengwook

    2012-01-01

    Consumption of fresh and fresh-cut fruits and vegetables contaminated with Escherichia coli O157:H7 has resulted in hundreds of cases of illness and, in some instances, death. In this study, the influence of cell surface structures of E. coli O157:H7, such as flagella, curli fimbriae, lipopolysaccharides, or exopolysaccharides, on plant defense responses and on survival or colonization on the plant was investigated. The population of the E. coli O157:H7 ATCC 43895 wild-type strain was significantly lower on wild-type Arabidopsis plants than that of the 43895 flagellum-deficient mutant. The population of the E. coli O157:H7 43895 flagellum mutant was greater on both wild-type and npr1-1 mutant (nonexpressor of pathogenesis-related [PR] genes) plants and resulted in less PR gene induction, estimated based on a weak β-glucuronidase (GUS) signal, than did the 43895 wild-type strain. These results suggest that the flagella, among the other pathogen-associated molecular patterns (PAMPs), made a substantial contribution to the induction of plant defense response and contributed to the decreased numbers of the E. coli O157:H7 ATCC 43895 wild-type strain on the wild-type Arabidopsis plant. A curli-deficient E. coli O157:H7 86-24 strain survived better on wild-type Arabidopsis plants than the curli-producing wild-type 86-24 strain did. The curli-deficient E. coli O157:H7 86-24 strain exhibited a GUS signal at a level substantially lower than that of the curli-producing wild-type strain. Curli were recognized by plant defense systems, consequently affecting bacterial survival. The cell surface structures of E. coli O157:H7 have a significant impact on the induction of differential plant defense responses, thereby impacting persistence or survival of the pathogen on plants. PMID:22706044

  2. Analysis of Escherichia coli O157:H7 Survival in Ovine or Bovine Manure and Manure Slurry

    PubMed Central

    Kudva, Indira T.; Blanch, Kathryn; Hovde, Carolyn J.

    1998-01-01

    Farm animal manure or manure slurry may disseminate, transmit, or propagate Escherichia coli O157:H7. In this study, the survival and growth of E. coli O157:H7 in ovine or bovine feces under various experimental and environmental conditions were determined. A manure pile collected from experimentally inoculated sheep was incubated outside under fluctuating environmental conditions. E. coli O157:H7 survived in the manure for 21 months, and the concentrations of bacteria recovered ranged from <102 to 106 CFU/g at different times over the course of the experiment. The DNA fingerprints of E. coli O157:H7 isolated at month 1 and month 12 were identical or very similar. A second E. coli O157:H7-positive ovine manure pile, which was periodically aerated by mixing, remained culture positive for 4 months. An E. coli O157:H7-positive bovine manure pile was culture positive for 47 days. In the laboratory, E. coli O157:H7 was inoculated into feces, untreated slurry, or treated slurry and incubated at −20, 4, 23, 37, 45, and 70°C. E. coli O157:H7 survived best in manure incubated without aeration at temperatures below 23°C, but it usually survived for shorter periods of time than it survived in manure held in the environment. The bacterium survived at least 100 days in bovine manure frozen at −20°C or in ovine manure incubated at 4 or 10°C for 100 days, but under all other conditions the length of time that it survived ranged from 24 h to 40 days. In addition, we found that the Shiga toxin type 1 and 2 genes in E. coli O157:H7 had little or no influence on bacterial survival in manure or manure slurry. The long-term survival of E. coli O157:H7 in manure emphasizes the need for appropriate farm waste management to curtail environmental spread of this bacterium. This study also highlights the difficulties in extrapolating laboratory data to on-farm conditions. PMID:9726855

  3. Virulence factors of verocytotoxin-producing Escherichia coli isolated from raw meats.

    PubMed Central

    Piérard, D; Van Damme, L; Moriau, L; Stevens, D; Lauwers, S

    1997-01-01

    PCR for verocytotoxin-producing Escherichia coli (VTEC) was positive in 4.6% of 2,440 raw meat samples; only beef, sheep, and venison samples were positive. None of the isolated VTEC strains belonged to serogroup O157. Additional virulence factors were detected in only a minority of strains, suggesting that most of these meat VTEC isolates are not pathogenic. PMID:9361444

  4. Predictors and risk factors for the intestinal shedding of Escherichia coli O157 among working donkeys (Equus asinus) in Nigeria

    PubMed Central

    Jedial, Jesse T.; Shittu, Aminu; Tambuwal, Faruk M.; Abubakar, Mikail B.; Garba, Muhammed K.; Kwaga, Jacob P.; Fasina, Folorunso O.

    2015-01-01

    Objectives Escherichia coli are an important group of bacteria in the normal gastrointestinal system but can sometimes cause infections in domestic animals and man. Donkeys are routinely used as multipurpose animal but details of burdens of potentially infectious bacteria associated with it are limited. The prevalence and associations between intestinal shedding of E. coli O157 and animal characteristics and management factors were studied among 240 randomly selected working donkeys in north-western Nigeria. Design Four local government areas, of Sokoto State in north-western Nigeria were recruited in this study. A multistage randomised cluster design was used to select subjects and donkey owners within selected zones. Confirmation of infection was based on bacterial culture, isolation and biochemical test for E. coli O157 from faecal samples. Results Of the total bacteria isolated, 203 of the 329 (61.70 per cent) were E. coli, 76 of which was E. coli serotype O157. A multivariable logistic regression model was used to examine the relation between intestinal shedding of E. coli O157 and selected variables. The analysis yielded five potential predictors of shedding: soft faeces in donkeys, Akaza and Fari ecotypes of donkey were positive predictors while maize straw as feed and sampling during the cold dry period were negative predictors. Conclusions This study concludes that controlling intestinal shedding of E. coli O157 among working donkeys in Nigeria is possible using the identified predictors in planning appropriate interventions to reduced human risk of infection. PMID:26392892

  5. Quantifying colonization potential of enterohemorrhagic Escherichia coli O157 using bovine in vitro organ culture and immunofluorescent staining.

    PubMed

    Brandt, Stephanie M; Paulin, Susan M

    2012-12-01

    A robust semiquantitative method for measuring the colonization potential of O157 enterohemorrhagic Escherichia coli (EHEC) strains was developed combining an established ex vivo model infection system, bovine in vitro organ culture, with detection of bacteria attached to tissue sections by immunofluorescent assay (bIVOC-IFA) using Quantum dot(®) nanocrystal technology. The method was tested on ten O157 strains chosen to reflect a diversity of genotypes found in New Zealand based on the novel polymerase chain reaction-binary typing (P-BIT) system. High- and low-colonizing EHEC O157 strains were identified using bIVOC-IFA, with the highest colonizing strain belonging to the pulsed-field gel electrophoresis type most commonly identified from New Zealand beef meat. Furthermore, all of the toxigenic O157 strains exhibiting a low-colonizing phenotype were closely related, belonging to the same P-BIT genotype cluster. Future use of this method to characterize EHEC strains could provide valuable information for risk assessment and risk management interventions aimed at improving food safety along the beef farm to fork continuum. PMID:23237407

  6. Difference between Escherichia coli O157:H7 and non-pathogenic E. coli: survival and growth in seasonings.

    PubMed

    Yokoigawa, K; Takikawa, A; Kawai, H

    1999-01-01

    We examined the survival and growth of Escherichia coli O157:H7 cells incubated with several seasonings, in comparison with those of non-pathogenic E. coli. The cells were incubated at 25 degrees C for 24 h with several concentrations of NaCl, sucrose, soy sauce, worcester sauce and tomato ketchup, and their survival ratios were determined. The E. coli O157:H7 strains showed relatively higher survival ratios in 0.5-1.0 M sucrose, 25% soy sauce and 12.5-50% worcester sauce than the non-pathogenic strains, but slightly lower survival ratios in 0.5-2.0 M NaCl. A noteworthy difference between E. coli O157:H7 and the non-pathogenic strains was that incubation in the presence of 12.5% soy sauce allowed the growth of E. coli O157:H7 strains but reduced the viable cell numbers of non-pathogenic E. coli strains. PMID:16232665

  7. SAS molecular tests Escherichia coli O157 detection kit. Performance tested method 031203.

    PubMed

    Bapanpally, Chandra; Montier, Laura; Khan, Shah; Kasra, Akif; Brunelle, Sharon L

    2014-01-01

    The SAS Molecular tests Escherichia coli O157 Detection method, a loop-mediated isothermal amplification method, performed as well as or better than the U.S. Department of Agriculture, Food Safety Inspection Service Microbiology Laboratory Guidebook and the U.S. Food and Drug Administration Bacteriological Analytical Manual reference methods for ground beef, beef trim, bagged mixed lettuce, and fresh spinach. Ground beef (30% fat, 25 g test portion) was validated for 7-8 h enrichment, leafy greens were validated in a 6-7 h enrichment, and ground beef (30% fat, 375 g composite test portion) and beef trim (375 g composite test portion) were validated in a 16-20 h enrichment. The method performance for meat and leafy green matrixes was also shown to be acceptable under conditions of co-enrichment with Salmonella. Thus, after a short co-enrichment step, ground beef, beef trim, lettuce, and spinach can be tested for both Salmonella and E. coli O157. The SAS Molecular tests Salmonella Detection Kit was validated using the same test portions as for the SAS Molecular tests E. coli O157 Detection Kit and those results are presented in a separate report. Inclusivity and exclusivity testing revealed no false negatives and no false positives among the 50 E. coli 0157 strains, including H7 and non-motile strains, and 30 non-E. coli O157 strains examined. Finally, the method was shown to be robust when variations to DNA extract hold time and DNA volume were varied. The method comparison and robustness data suggest a full 7 h enrichment time should be used for 25 g ground beef test portions. PMID:25051628

  8. Evaluation of commonly used antimicrobial interventions for fresh beef inoculated with Shiga toxin-producing Escherichia coli serotypes O26, O45, O103, O111, O121, O145, and O157:H7

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although numerous antimicrobial interventions targeting E. coli O157:H7 have been developed and implemented to decontaminate meat and meat products during the harvesting process, the information on efficacy of these interventions, against the “big six” non-O157 STEC strains is limited. One-hundred a...

  9. Survival of Escherichia coli O157:H7 ATCC 43895 in a Model Apple Juice Medium with Different Concentrations of Proline and Caffeic Acid

    PubMed Central

    Reinders, Robert D.; Biesterveld, Steef; Bijker, Peter G. H.

    2001-01-01

    The effects of proline and caffeic acid on the survival of Shiga toxin-producing Escherichia coli (STEC) O157:H7 strain ATCC 43895 in a model apple juice medium were studied. It is hypothesized that the inhibitory effect of caffeic acid may explain why almost all outbreaks of STEC O157:H7 infections linked to apple juice or cider have occurred in October or November. PMID:11375209

  10. Use of Potential Probiotic Lactic Acid Bacteria (LAB) Biofilms for the Control of Listeria monocytogenes, Salmonella Typhimurium, and Escherichia coli O157:H7 Biofilms Formation

    PubMed Central

    Gómez, Natacha C.; Ramiro, Juan M. P.; Quecan, Beatriz X. V.; de Melo Franco, Bernadette D. G.

    2016-01-01

    Use of probiotic biofilms can be an alternative approach for reducing the formation of pathogenic biofilms in food industries. The aims of this study were (i) to evaluate the probiotic properties of bacteriocinogenic (Lactococcus lactis VB69, L. lactis VB94, Lactobacillus sakei MBSa1, and Lactobacillus curvatus MBSa3) and non-bacteriocinogenic (L. lactis 368, Lactobacillus helveticus 354, Lactobacillus casei 40, and Weissela viridescens 113) lactic acid bacteria (LAB) isolated from Brazilian’s foods and (ii) to develop protective biofilms with these strains and test them for exclusion of Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella Typhimurium. LAB were tested for survival in acid and bile salt conditions, surface properties, biosurfactant production, β-galactosidase and gelatinase activity, antibiotic resistance and presence of virulence genes. Most strains survived exposure to pH 2 and 4% bile salts. The highest percentages of auto-aggregation were obtained after 24 h of incubation. Sixty-seven percentage auto-aggregation value was observed in W. viridescens 113 and Lactobacillus curvatus MBSa3 exhibited the highest co-aggregation (69% with Listeria monocytogenes and 74.6% with E. coli O157:H7), while the lowest co-aggregation was exhibited by W. viridescens 113 (53.4% with Listeria monocytogenes and 38% with E. coli O157:H7). Tests for hemolytic activity, bacterial cell adherence with xylene, and drop collapse confirmed the biosurfactant-producing ability of most strains. Only one strain (L. lactis 368) produced β-galactosidase. All strains were negative for virulence genes cob, ccf, cylLL, cylLs, cyllM, cylB, cylA and efaAfs and gelatinase production. The antibiotic susceptibility tests indicated that the MIC for ciprofloxacin, clindamycin, gentamicin, kanamycin, and streptomycin did not exceed the epidemiological cut-off suggested by the European Food Safety Authority. Some strains were resistant to one or more antibiotics and

  11. Use of Potential Probiotic Lactic Acid Bacteria (LAB) Biofilms for the Control of Listeria monocytogenes, Salmonella Typhimurium, and Escherichia coli O157:H7 Biofilms Formation.

    PubMed

    Gómez, Natacha C; Ramiro, Juan M P; Quecan, Beatriz X V; de Melo Franco, Bernadette D G

    2016-01-01

    Use of probiotic biofilms can be an alternative approach for reducing the formation of pathogenic biofilms in food industries. The aims of this study were (i) to evaluate the probiotic properties of bacteriocinogenic (Lactococcus lactis VB69, L. lactis VB94, Lactobacillus sakei MBSa1, and Lactobacillus curvatus MBSa3) and non-bacteriocinogenic (L. lactis 368, Lactobacillus helveticus 354, Lactobacillus casei 40, and Weissela viridescens 113) lactic acid bacteria (LAB) isolated from Brazilian's foods and (ii) to develop protective biofilms with these strains and test them for exclusion of Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella Typhimurium. LAB were tested for survival in acid and bile salt conditions, surface properties, biosurfactant production, β-galactosidase and gelatinase activity, antibiotic resistance and presence of virulence genes. Most strains survived exposure to pH 2 and 4% bile salts. The highest percentages of auto-aggregation were obtained after 24 h of incubation. Sixty-seven percentage auto-aggregation value was observed in W. viridescens 113 and Lactobacillus curvatus MBSa3 exhibited the highest co-aggregation (69% with Listeria monocytogenes and 74.6% with E. coli O157:H7), while the lowest co-aggregation was exhibited by W. viridescens 113 (53.4% with Listeria monocytogenes and 38% with E. coli O157:H7). Tests for hemolytic activity, bacterial cell adherence with xylene, and drop collapse confirmed the biosurfactant-producing ability of most strains. Only one strain (L. lactis 368) produced β-galactosidase. All strains were negative for virulence genes cob, ccf, cylLL, cylLs, cyllM, cylB, cylA and efaAfs and gelatinase production. The antibiotic susceptibility tests indicated that the MIC for ciprofloxacin, clindamycin, gentamicin, kanamycin, and streptomycin did not exceed the epidemiological cut-off suggested by the European Food Safety Authority. Some strains were resistant to one or more antibiotics and resistance

  12. Assessments of Total and Viable Escherichia coli O157:H7 on Field and Laboratory Grown Lettuce

    PubMed Central

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

    2013-01-01

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

  13. Standardized Escherichia coli O157:H7 Exposure Studies in Cattle Provide Evidence that Bovine Factors Do Not Drive Increased Summertime Colonization

    PubMed Central

    Sheng, Haiqing; Shringi, Smriti; Baker, Katherine N. K.; Minnich, Scott A.; Hovde, Carolyn J.

    2015-01-01

    The increased summertime prevalence of cattle carriage of enterohemorrhagic Shiga toxin-producing Escherichia coli O157:H7 (STEC O157) is associated with the increased summertime incidence of human infection. The mechanism driving the seasonality of STEC O157 carriage among cattle is unknown. We conducted experimental challenge trials to distinguish whether factors extrinsic or intrinsic to cattle underlie the seasonality of STEC O157 colonization. Holstein steers (n = 20) exposed to ambient environmental conditions were challenged with a standardized pool of STEC O157 strains four times at 6-month intervals. The densities and durations of rectoanal junction mucosa (RAJ) colonization with STEC O157 were compared by season (winter versus summer), dose (109 CFU versus 107 CFU), and route of challenge (oral versus rectal). Following summer challenges, the RAJ STEC O157 colonization density was significantly lower (P = 0.016) and the duration was shorter (P = 0.052) than for winter challenges, a seasonal pattern opposite to that observed naturally. Colonization was unaffected by the challenge route, indicating that passage through the gastrointestinal microbiome did not significantly affect the infectious dose to the RAJ. A 2-log reduction of the challenge doses in the second-year trials was accompanied by similarly reduced RAJ colonization in both seasons (P < 0.001). These results refute the hypothesis that cattle are predisposed to STEC O157 colonization during the summer months, either due to intrinsic factors or indirectly due to gastrointestinal tract microbiome effects. Instead, the data support the hypothesis that the increased summertime STEC O157 colonization results from increased seasonal oral exposure to this pathogen. PMID:26607594

  14. Saltelli Global Sensitivity Analysis and Simulation Modelling to Identify Intervention Strategies to Reduce the Prevalence of Escherichia coli O157 Contaminated Beef Carcasses

    PubMed Central

    Brookes, Victoria J.; Jordan, David; Davis, Stephen; Ward, Michael P.; Heller, Jane

    2015-01-01

    Introduction Strains of Shiga-toxin producing Escherichia coli O157 (STEC O157) are important foodborne pathogens in humans, and outbreaks of illness have been associated with consumption of undercooked beef. Here, we determine the most effective intervention strategies to reduce the prevalence of STEC O157 contaminated beef carcasses using a modelling approach. Method A computational model simulated events and processes in the beef harvest chain. Information from empirical studies was used to parameterise the model. Variance-based global sensitivity analysis (GSA) using the Saltelli method identified variables with the greatest influence on the prevalence of STEC O157 contaminated carcasses. Following a baseline scenario (no interventions), a series of simulations systematically introduced and tested interventions based on influential variables identified by repeated Saltelli GSA, to determine the most effective intervention strategy. Results Transfer of STEC O157 from hide or gastro-intestinal tract to carcass (improved abattoir hygiene) had the greatest influence on the prevalence of contaminated carcases. Due to interactions between inputs (identified by Saltelli GSA), combinations of interventions based on improved abattoir hygiene achieved a greater reduction in maximum prevalence than would be expected from an additive effect of single interventions. The most effective combination was improved abattoir hygiene with vaccination, which achieved a greater than ten-fold decrease in maximum prevalence compared to the baseline scenario. Conclusion Study results suggest that effective interventions to reduce the prevalence of STEC O157 contaminated carcasses should initially be based on improved abattoir hygiene. However, the effect of improved abattoir hygiene on the distribution of STEC O157 concentration on carcasses is an important information gap—further empirical research is required to determine whether reduced prevalence of contaminated carcasses is

  15. Bacteriophage cocktail significantly reduces Escherichia coli O157

    PubMed Central

    Carter, Chandi D.; Parks, Adam; Abuladze, Tamar; Li, Manrong; Woolston, Joelle; Magnone, Joshua; Senecal, Andre; Kropinski, Andrew M.; Sulakvelidze, Alexander

    2012-01-01

    Foods contaminated with Escherichia coli O157:H7 cause more than 63,000 foodborne illnesses in the United States every year, resulting in a significant economic impact on medical costs and product liabilities. Efforts to reduce contamination with E. coli O157:H7 have largely focused on washing, application of various antibacterial chemicals, and gamma-irradiation, each of which has practical and environmental drawbacks. A relatively recent, environmentally-friendly approach proposed for eliminating or significantly reducing E. coli O157:H7 contamination of foods is the use of lytic bacteriophages as biocontrol agents. We found that EcoShield™, a commercially available preparation composed of three lytic bacteriophages specific for E. coli O157:H7, significantly (p < 0.05) reduced the levels of the bacterium in experimentally contaminated beef by ≥ 94% and in lettuce by 87% after a five minute contact time. The reduced levels of bacteria were maintained for at least one week at refrigerated temperatures. However, the one-time application of EcoShield™ did not protect the foods from recontamination with E. coli O157:H7. Our results demonstrate that EcoShield™ is effective in significantly reducing contamination of beef and lettuce with E. coli O157:H7, but does not protect against potential later contamination due to, for example, unsanitary handling of the foods post processing. PMID:23275869

  16. Clinical Escherichia coli Strains Carrying stx Genes: stx Variants and stx-Positive Virulence Profiles

    PubMed Central

    Eklund, Marjut; Leino, Kirsikka; Siitonen, Anja

    2002-01-01

    Altogether, 173 Shiga toxin-producing Escherichia coli (STEC) serotype O157 (n = 111) and non-O157 (n = 62) isolates from 170 subjects were screened by PCR-restriction fragment length polymorphism for eight different stx genes. The results were compiled according to serotypes, phage types of O157, production of Stx toxin and enterohemolysin, and the presence of eae. The stx genes occurred in 11 combinations; the most common were stx2 with stx2c (42%), stx2 alone (21%), and stx1 alone (16%). Of the O157 strains, 64% carried stx2 with stx2c versus 2% of the non-O157 strains (P < 0.001). In the non-O157 strains, the prevailing gene was stx1 (99% versus 1% in O157 strains; P < 0.001). In addition, one strain (O Rough:H4:stx2c) which has not previously been described as associated with hemolytic-uremic syndrome (HUS) was found. Ten stx-positive virulence profiles were responsible for 71% of all STEC infections. Of these profiles, five accounted for 71% of the 21 strains isolated from 20 patients with HUS or thrombotic thrombocytopenic purpura (TTP). The strains having the virulence profile that caused mainly HUS or TTP or bloody diarrhea produced Stx with titers of ≥1:128 (90%) more commonly than did other strains (51%; P < 0.001). These strains were also more commonly enterohemolytic (98% versus 68% for other strains; P < 0.001) and possessed the eae gene (100%) more commonly than did other strains (74%; P < 0.001). A particular virulence profile, O157:H7:PT2:stx2:stx2c:eae:Ehly, was significantly more frequently associated with HUS and bloody diarrhea than were other profiles (P = 0.02) and also caused the deaths of two children. In this study, the risk factors for severe symptoms were an age of <5 years and infection by the strain of O157:H7:PT2 mentioned above. PMID:12454157

  17. Cold Plasma Inactivates Salmonella Stanley and Escherichia coli O157:H7 Inoculated on Golden Delicious Apples

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cold plasma generated in a gliding arc was applied to outbreak strains of Escherichia coli O157:H7 and Salmonella Stanley on agar plates and inoculated onto the surfaces of golden delicious apples. This novel sanitizing technology inactivated both pathogens on agar plates, with higher flow rate (40 ...

  18. Carvacrol and Cinnamaldehyde Facilitate Thermal Destruction of Escherichia coli O157:H7 in Raw Ground Beef

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The heat resistance of a four-strain mixture of Escherichia coli O157:H7 in raw ground beef in both the absence and presence of the natural antimicrobials, carvacrol and cinnamaldehyde, was tested at temperatures ranging from 55 to 62.5C. Inoculated meat, packaged in bags, was completely immersed i...

  19. Native protozoa decrease Escherichia coli O157:H7 in microcosms of wastewater from a dairy lagoon

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Since protozoa constitute almost half of rumen microbial biomass and regulate rumen microbial ecosystem, we evaluated the influence of protozoa in wastewater from a dairy lagoon on the fate of pathogenic strains of Escherichia coli O157:H7 marked with antibiotic resistance. Protozoan populations in ...

  20. Antimicrobial effects of weak acids on the survival of Escherichia coli O157:H7 under anaerobic conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Outbreaks of disease due to vegetative bacterial pathogens associated with acid foods (such as apple cider) have raised concerns about acidified vegetables and related products that have a similar pH (3.2 to 4.0). Escherichia coli O157:H7 and related strains of enterohemorrhagic E. coli (EHEC) have ...

  1. Curli fimbriae are conditionally required in Escherichia coli O157:H7 for initial attachment and biofilm formation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Several species of enteric pathogens produce curli fimbriae, which may affect their interaction with surfaces and other microbes in nonhost environments. Here we used two E. coli O157:H7 outbreak strains with distinct genotypes to understand the role of curli in surface attachment and biofilm format...

  2. Natural rpoS mutations contribute to the phenotypic heterogeneity of clonal populations in Escherichia coli O157:H7

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We previously reported the distinct acid resistance between the curli-producing (C+) and curli-deficient (C-) variants of E. coli O157:H7, although the curli fimbriae were not associated with this intra-strain phenotypic divergence. Here we investigated the underlying molecular mechanism by examinin...

  3. Classification of non-O157 shiga toxin-producing escherichia coli(STEC) serotypes with hyperspectral microscope imaging

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Non-O157 Shiga toxin-producing Escherichia coli (STEC) strains such as O26, O45, O103, O111, O121 and O145 are recognized as serious outbreak to cause human illness due to their toxicity. A conventional microbiological method for cell counting is laborious and needs long time for the results. Since ...

  4. TEA LEAF AND APPLE SKIN POWDERS FACILITATE THERMAL DESTRUCTION OF ESCHERICHIA COLI O157:H7 IN RAW GROUND BEEF

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We investigated the heat resistance of a four-strain mixture of Escherichia coli O157:H7 in raw ground beef in both the absence and presence of white and green tea powders and an apple skin extract. Inoculated meat, packaged in bags, was completely immersed in a circulating water bath and cooked fo...

  5. Effect of curli expression and hydrophobicity of E. coli O157:H7 on attachment to fresh produce surfaces

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aim: To investigate the effect of curli expression on cell hydrophobicity, biofilm formation, and attachment to cut and intact fresh produce surfaces. Methods and Results: Five E. coli O157:H7 strains were evaluated for curli expression, hydrophobicity, biofilm formation, and attachment of E. co...

  6. Quantitative detection of E. coli, E. coli O157 and other shiga toxin producing E. coli in water samples using a culture method combined with real-time PCR.

    PubMed

    Heijnen, Leo; Medema, Gertjan

    2006-12-01

    Recent water related outbreaks of shiga toxin producing E. coli O157 have resulted in increased attention of the water industry to this potentially deadly pathogen. Current methods to detect E. coli O157 and its virulence genes are laborious and time-consuming. Specificity, sensitivity and simple use of a real-time PCR method makes it an attractive alternative for the detection of STEC E. coli O157. This study describes the development and application of real-time PCR methods for the detection of E. coli O157, shiga toxin genes (Stx1 and Stx2) and E. coli. The specificity of the methods was confirmed by performing colony-PCR assays on characterized bacterial isolates, demonstrating the applicability of these assays as rapid tests to confirm the presence of E. coli or E. coli O157 colonies on culture plates. Sensitive culture-PCR methods were developed by combining culture enrichment with real-time PCR detection. This rapid method allowed detection of low concentrations of E. coli O157 in the presence of high concentrations of non-O157-E. coli (1:104). Culture-PCR methods were applied to 27 surface water and 4 wastewater samples. E. coli O157 and both Stx genes were detected in two wastewater samples, whereas only E. coli O157 was detected in two surface water samples. Culture-PCR methods were not influenced by matrix effects and also enabled quantitative (MPN) detection of E. coli in these samples. PMID:17176819

  7. The Defective Prophage Pool of Escherichia coli O157: Prophage–Prophage Interactions Potentiate Horizontal Transfer of Virulence Determinants

    PubMed Central

    Asadulghani, Md; Ogura, Yoshitoshi; Ooka, Tadasuke; Itoh, Takehiko; Sawaguchi, Akira; Iguchi, Atsushi; Nakayama, Keisuke; Hayashi, Tetsuya

    2009-01-01

    Bacteriophages are major genetic factors promoting horizontal gene transfer (HGT) between bacteria. Their roles in dynamic bacterial genome evolution have been increasingly highlighted by the fact that many sequenced bacterial genomes contain multiple prophages carrying a wide range of genes. Enterohemorrhagic Escherichia coli O157 is the most striking case. A sequenced strain (O157 Sakai) possesses 18 prophages (Sp1–Sp18) that encode numerous genes related to O157 virulence, including those for two potent cytotoxins, Shiga toxins (Stx) 1 and 2. However, most of these prophages appeared to contain multiple genetic defects. To understand whether these defective prophages have the potential to act as mobile genetic elements to spread virulence determinants, we looked closely at the Sp1–Sp18 sequences, defined the genetic defects of each Sp, and then systematically analyzed all Sps for their biological activities. We show that many of the defective prophages, including the Stx1 phage, are inducible and released from O157 cells as particulate DNA. In fact, some prophages can even be transferred to other E. coli strains. We also show that new Stx1 phages are generated by recombination between the Stx1 and Stx2 phage genomes. The results indicate that these defective prophages are not simply genetic remnants generated in the course of O157 evolution, but rather genetic elements with a high potential for disseminating virulence-related genes and other genetic traits to other bacteria. We speculate that recombination and various other types of inter-prophage interactions in the O157 prophage pool potentiate such activities. Our data provide new insights into the potential activities of the defective prophages embedded in bacterial genomes and lead to the formulation of a novel concept of inter-prophage interactions in defective prophage communities. PMID:19412337

  8. Synchronization of E. coli O157 shedding in a grass-fed beef herd: a longitudinal study.

    PubMed

    Lammers, G A C; McCONNEL, C S; Jordan, D; Ayton, M S; Morris, S; Patterson, E I; Ward, M P; Heller, J

    2015-11-01

    This study aims to describe in detail the temporal dynamics of E. coli O157 shedding and risk factors for shedding in a grass-fed beef herd. During a 9-month period, 23 beef cows were sampled twice a week (58 sampling points) and E. coli O157 was enumerated from faecal samples. Isolates were screened by PCR for presence of rfbE, stx 1 and stx 2 . The prevalence per sampling day ranged from 0% to 57%. This study demonstrates that many members of the herd were concurrently shedding E. coli O157. Occurrence of rainfall (P < 0·01), feeding silage (P < 0·01) and lactating (P < 0·01) were found to be predictors of shedding. Moving cattle to a new paddock had a negative effect on shedding. This approach, based on short-interval sampling, confirms the known variability of shedding within a herd and highlights that high shedding events are rare. PMID:25823915

  9. Development of a robust method for isolation of shiga toxin-positive Escherichia coli (STEC) from fecal, plant, soil and water samples from a leafy greens production region in California.

    PubMed

    Cooley, Michael B; Jay-Russell, Michele; Atwill, Edward R; Carychao, Diana; Nguyen, Kimberly; Quiñones, Beatriz; Patel, Ronak; Walker, Samarpita; Swimley, Michelle; Pierre-Jerome, Edith; Gordus, Andrew G; Mandrell, Robert E

    2013-01-01

    During a 2.5-year survey of 33 farms and ranches in a major leafy greens production region in California, 13,650 produce, soil, livestock, wildlife, and water samples were tested for Shiga toxin (stx)-producing Escherichia coli (STEC). Overall, 357 and 1,912 samples were positive for E. coli O157:H7 (2.6%) or non-O157 STEC (14.0%), respectively. Isolates differentiated by O-typing ELISA and multilocus variable number tandem repeat analysis (MLVA) resulted in 697 O157:H7 and 3,256 non-O157 STEC isolates saved for further analysis. Cattle (7.1%), feral swine (4.7%), sediment (4.4%), and water (3.3%) samples were positive for E. coli O157:H7; 7/32 birds, 2/145 coyotes, 3/88 samples from elk also were positive. Non-O157 STEC were at approximately 5-fold higher incidence compared to O157 STEC: cattle (37.9%), feral swine (21.4%), birds (2.4%), small mammals (3.5%), deer or elk (8.3%), water (14.0%), sediment (12.3%), produce (0.3%) and soil adjacent to produce (0.6%). stx1, stx2 and stx1/stx2 genes were detected in 63%, 74% and 35% of STEC isolates, respectively. Subtilase, intimin and hemolysin genes were present in 28%, 25% and 79% of non-O157 STEC, respectively; 23% were of the "Top 6″ O-types. The initial method was modified twice during the study revealing evidence of culture bias based on differences in virulence and O-antigen profiles. MLVA typing revealed a diverse collection of O157 and non-O157 STEC strains isolated from multiple locations and sources and O157 STEC strains matching outbreak strains. These results emphasize the importance of multiple approaches for isolation of non-O157 STEC, that livestock and wildlife are common sources of potentially virulent STEC, and evidence of STEC persistence and movement in a leafy greens production environment. PMID:23762414

  10. Development of a Robust Method for Isolation of Shiga Toxin-Positive Escherichia coli (STEC) from Fecal, Plant, Soil and Water Samples from a Leafy Greens Production Region in California

    PubMed Central

    Cooley, Michael B.; Jay-Russell, Michele; Atwill, Edward R.; Carychao, Diana; Nguyen, Kimberly; Quiñones, Beatriz; Patel, Ronak; Walker, Samarpita; Swimley, Michelle; Pierre-Jerome, Edith; Gordus, Andrew G.; Mandrell, Robert E.

    2013-01-01

    During a 2.5-year survey of 33 farms and ranches in a major leafy greens production region in California, 13,650 produce, soil, livestock, wildlife, and water samples were tested for Shiga toxin (stx)-producing Escherichia coli (STEC). Overall, 357 and 1,912 samples were positive for E. coli O157:H7 (2.6%) or non-O157 STEC (14.0%), respectively. Isolates differentiated by O-typing ELISA and multilocus variable number tandem repeat analysis (MLVA) resulted in 697 O157:H7 and 3,256 non-O157 STEC isolates saved for further analysis. Cattle (7.1%), feral swine (4.7%), sediment (4.4%), and water (3.3%) samples were positive for E. coli O157:H7; 7/32 birds, 2/145 coyotes, 3/88 samples from elk also were positive. Non-O157 STEC were at approximately 5-fold higher incidence compared to O157 STEC: cattle (37.9%), feral swine (21.4%), birds (2.4%), small mammals (3.5%), deer or elk (8.3%), water (14.0%), sediment (12.3%), produce (0.3%) and soil adjacent to produce (0.6%). stx1, stx2 and stx1/stx2 genes were detected in 63%, 74% and 35% of STEC isolates, respectively. Subtilase, intimin and hemolysin genes were present in 28%, 25% and 79% of non-O157 STEC, respectively; 23% were of the “Top 6″ O-types. The initial method was modified twice during the study revealing evidence of culture bias based on differences in virulence and O-antigen profiles. MLVA typing revealed a diverse collection of O157 and non-O157 STEC strains isolated from multiple locations and sources and O157 STEC strains matching outbreak strains. These results emphasize the importance of multiple approaches for isolation of non-O157 STEC, that livestock and wildlife are common sources of potentially virulent STEC, and evidence of STEC persistence and movement in a leafy greens production environment. PMID:23762414

  11. Increase in activity of essential oil components carvacrol and thymol against Escherichia coli O157:H7 by addition of food stabilizers.

    PubMed

    Burt, Sara A; Vlielander, René; Haagsman, Henk P; Veldhuizen, Edwin J A

    2005-05-01

    The major components of oregano and thyme essential oils that had previously been shown to inhibit Escherichia coli O157:H7 were determined by high-performance liquid chromatography with UV detection and liquid chromatographic tandem mass spectrometry. The MICs and MBCs of carvacrol, thymol, p-cymene, and gamma-terpinene against a strain of E. coli O157: H7 phage type 34 isolated from bovine feces were determined by microdilution assay. The constituents were then tested in checkerboard assays to detect possible interactions. Carvacrol and thymol displayed bacteriostatic and bactericidal properties with MICs of 1.2 mmol/liter and were additive in combination. p-Cymene and gamma-terpinene displayed no measurable antibacterial activity up to 50 mmol/liter, and neither influenced the activity of carvacrol or thymol. Growth curves in the presence of nonlethal concentrations of carvacrol with the addition of agar (0.05%, wt/vol) or carrageenan (0.125%, wt/vol) as stabilizer were produced by optical density measurement. The stabilizers agar and carrageenan both significantly improved the effectiveness of carvacrol in broth, possibly because of a delay in the separation of the hydrophobic substrate from the aqueous phase of the medium. When carvacrol was dissolved in ethanol before addition to broth, stabilizers were not needed. Carvacrol and thymol, particularly when used in combination with a stabilizer or in an ethanol solution, may be effective in reducing the number or preventing growth of E. coli O157:H7 in liquid foods. PMID:15895722

  12. Evaluation of Escherichia coli biotype 1 as a surrogate for Escherichia coli O157:H7 for cooking, fermentation, freezing, and refrigerated storage in meat processes.

    PubMed

    Keeling, Carisa; Niebuhr, Steven E; Acuff, Gary R; Dickson, James S

    2009-04-01

    Five Escherichia coli biotype I isolates were compared with E. coli O157:H7 under four common meat processing conditions. The processes that were evaluated were freezing, refrigerating, fermentation, and thermal inactivation. For each study, at least one surrogate organism was not statistically different when compared with E. coli O157:H7. However, the four studies did not consistently show the same isolate as having this agreement. The three studies that involved temperature as a method of controlling or reducing the E. coli population all had at least one possible surrogate in common. In the fermentation study, only one isolate (BAA-1429) showed no statistical difference when compared with E. coli O157:H7. However, the population reductions that were observed indicated the isolates BAA-1427 and BAA-1431 would overestimate the surviving E. coli O157:H7 population in a fermented summer sausage. When all of the data from all of the surrogates were examined, it was found that isolates BAA-1427, BAA-1429, and BAA-1430 would be good surrogates for all four of the processes that were examined in this study. There was no statistical difference noted between these three isolates and E. coli O157:H7 in the refrigeration study. These isolates resulted in smaller population reductions than did E. coli O157:H7 in the frozen, fermentation, and thermal inactivation studies. This would indicate that these isolates would overpredict the E. coli O157:H7 population in these three instances. This overprediction results in an additional margin of safety when using E. coli biotype 1 as a surrogate. PMID:19435219

  13. Serotypes, Virulence Genes, and Intimin Types of Shiga Toxin (Verotoxin)-Producing Escherichia coli Isolates from Human Patients: Prevalence in Lugo, Spain, from 1992 through 1999

    PubMed Central

    Blanco, J. E.; Blanco, M.; Alonso, M. P.; Mora, A.; Dahbi, G.; Coira, M. A.; Blanco, J.

    2004-01-01

    We have analyzed the prevalence of Shiga toxin-producing Escherichia coli (STEC) in stool specimens of patients with diarrhea or other gastrointestinal alterations from the Xeral-Calde Hospital of Lugo City (Spain). STEC strains were detected in 126 (2.5%) of 5,054 cases investigated, with a progressive increase in the incidence from 0% in 1992 to 4.4% in 1999. STEC O157:H7 was isolated in 24 cases (0.5%), whereas non-O157 STEC strains were isolated from 87 patients (1.7%). STEC strains were (after Salmonella and Campylobacter strains) the third most frequently recovered enteropathogenic bacteria. A total of 126 human STEC isolates were characterized in this study. PCR showed that 43 (34%) isolates carried stx1 genes, 45 (36%) possessed stx2 genes and 38 (30%) carried both stx1 and stx2. A total of 88 (70%) isolates carried an ehxA enterohemolysin gene, and 70 (56%) isolates possessed an eae intimin gene (27 isolates with type γ1, 20 with type β1, 8 with type ζ, 5 with type γ2, and 3 with type ɛ). STEC isolates belonged to 41 O serogroups and 66 O:H serotypes, including 21 serotypes associated with hemolytic uremic syndrome and 30 new serotypes not previously reported among human STEC strains in other studies. Although the 126 STEC isolates belonged to 81 different seropathotypes (associations between serotypes and virulence genes), only four accounted for 31% of isolates. Seropathotype O157:H7 stx1 stx2 eae-γ1 ehxA was the most common (13 isolates) followed by O157:H7 stx2 eae-γ1 ehxA (11 isolates), O26:H11 stx1 eae-β1 ehxA (11 isolates), and O111:H- stx1 stx2 eae-γ2 ehxA (4 isolates). Our results suggest that STEC strains are a significant cause of human infections in Spain and confirm that in continental Europe, infections caused by STEC non-O157 strains are more common than those caused by O157:H7 isolates. The high prevalence of STEC strains (both O157:H7 and non-O157 strains) in human patients, and their association with serious complications

  14. Escherichia coli O157:H7 in Feral Swine Near Spinach Fields and Cattle, Central California Coast

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We investigated involvement of feral swine in contamination of agriculture fields and surface waterways with Escherichia coli O157:H7 after a nationwide outbreak traced to bagged spinach from California. Isolates from feral swine, cattle, surface water, sediment, and soil at 1 ranch were matched to ...

  15. Application of horse-radish peroxidase linked chemiluminescence to determine the production mechanism of Shiga-like toxins by E. coli O157:H7

    NASA Astrophysics Data System (ADS)

    Tu, Shu-I.; Uknalis, Joseph; Gehring, Andrew; He, Yiping

    2007-09-01

    A sandwiched immunoassay consisting of toxin capture by immunomagnetic beads (IMB) and toxin detection by horseradish peroxidase (HRP) linked chemiluminescence was used to follow the production of Shiga-like toxins (SLT) by E. coli O157:H7. The intensity of luminescence generated by the oxidation of luminol-liked compounds was used to represent the concentration of toxins produced. The time-course of SLT production by E. coli O157:H7 under different conditions was investigated. In pure culture, optimal generation of SLT showed a significant delay than the steady state of cell growth. In mixed cultures of SLT producing E. coli O157:H7 and non-SLT producing E. coli K-12 strain, the production of toxins was substantially decreased. However, the growth of E. coli O157:H7 was not affected by the presence of K-12 strain. This decrease in SLT production was also observed in radiation-sterile ground beef. In regular ground beef that might contain numerous other bacteria, the growth of E. coli O157:H7 in EC media was not significantly affected but the lowered production of SLT was observed. The results showed that mechanism of inducing SLT production was complex with both the growth time and growth environment could influence SLT production. The addition of homo-serine lactone to the growth media enhanced the production of SLT. Thus, possibly cell-cell communication may have a role in SLT production by E. coli O157:H7.

  16. Validation of the Applied Biosystems MicroSEQ real-time PCR system for detection of E. coli O157:H7 in food.

    PubMed

    Wong, Lily Y; Cao, Yanxiang; Balachandran, Priya; Zoder, Patrick; Furtado, Manohar R; Petrauskene, Olga V; Tebbs, Robert S

    2012-01-01

    Modern molecular methods offer the advantages of simplicity and short time-to-results compared to traditional culture methods. We describe the validation of a new Real-Time PCR method to detect E. coli O157:H7 in five food matrixes. The complete system consists of the MicroSEQ E. coli O157:H7 Detection Kit, sample preparation (two sample preparation methods, the PrepSEQ Nucleic Acid Extraction Kit and the PrepSEQ Rapid Spin Sample Preparation Kit, were validated), the Applied Biosystems 7500 Fast Real-Time PCR instrument, and RapidFinder Express software. The test method was compared to the U.S. Department of Agriculture Microbiology Laboratory Guidebook 5.04 reference method for detecting E. coli O157:H7 in 25 g and 375 g ground beef and beef trim, and to the ISO 16654 reference method for detecting E. coli O157:H7 in 25 g spinach, orange juice, and apple juice. The MicroSEQ E. coli O157:H7 Detection Kit showed equivalent detection compared to the corresponding reference method based on Mantel-Haenszel Chi-square statistics for all matrixes tested. An independent validation confirmed these findings on ground beef. The MicroSEQ kit detected all 51 E. coli O157:H7 strains tested and showed good discrimination against an exclusivity panel of 30 strains. PMID:23175985

  17. Survival of bioluminescent Listeria monocytogenes and Escherichia coli O157:H7 in soft cheeses.

    PubMed

    Ramsaran, H; Chen, J; Brunke, B; Hill, A; Griffiths, M W

    1998-07-01

    Pasteurized and raw milks that had been inoculated at 10(4) cfu/ml with bioluminescent strains of Listeria monocytogenes and Escherichia coli O157:H7 were used in the manufacture of Camembert and Feta cheeses with or without nisin-producing starter culture. Survival of both organisms was determined during the manufacture and storage of Camembert and Feta cheeses at 2 +/- 1 degree C for 65 and 75 d, respectively. Bacterial bioluminescence was used as an indicator to enumerate the colonies plated on selective Listeria agar and on MacConkey agar. Escherichia coli O157:H7 survived the manufacturing process of both cheeses and was present at the end of the storage period in greater numbers than in the initial inoculum. At the end of 75 d of storage, E. coli O157:H7 was found in the brine of Feta cheese. The counts of L. monocytogenes increased as the pH of the Camembert cheese increased, and there were significant differences between the counts from samples taken from the inside and the counts from samples obtained near the surface of the cheese. The Feta cheese that contained nisin was the only cheese in which L. monocytogenes was at the level of the initial inoculum after 75 d of storage. PMID:9710748

  18. Effectiveness of Active Packaging on Control of Escherichia Coli O157:H7 and Total Aerobic Bacteria on Iceberg Lettuce.

    PubMed

    Lu, Haixia; Zhu, Junli; Li, Jianrong; Chen, Jinru

    2015-06-01

    Contaminated leafy green vegetables have been linked to several outbreaks of human gastrointestinal infections. Antimicrobial interventions that are adoptable by the fresh produce industry for control of pathogen contamination are in great demand. This study was undertaken to evaluate the efficacy of sustained active packaging on control of Escherichia coli O157:H7 and total aerobic bacteria on lettuce. Commercial Iceberg lettuce was inoculated with a 3-strain mixture of E. coli O157:H7 at 10(2) or 10(4) CFU/g. The contaminated lettuce and un-inoculated controls were placed respectively in 5 different active packaging structures. Traditional, nonactive packaging structure was included as controls. Packaged lettuce was stored at 4, 10, or 22 °C for 3 wk and sampled weekly for the population of E. coli O157:H7 and total aerobic bacteria. Results showed that packaging structures with ClO2 generator, CO2 generator, or one of the O2 scavengers effectively controlled the growth of E. coli O157:H7 and total aerobic bacteria under all storage conditions. Packaging structure with the ClO2 generator was most effective and no E. coli O157:H7 was detected in samples packaged in this structure except for those that were inoculated with 4 log CFU/g of E. coli O157:H7 and stored at 22 °C. Packaging structures with an oxygen scavenger and the allyl isothiocyanate generator were mostly ineffective in control of the growth of the bacteria on Iceberg lettuce. The research suggests that some of the packaging structures evaluated in the study can be used to control the presence of foodborne pathogens on leafy green vegetables. PMID:25974213

  19. Factors contributing to the emergence of Escherichia coli O157 in Africa.

    PubMed Central

    Effler, E.; Isaäcson, M.; Arntzen, L.; Heenan, R.; Canter, P.; Barrett, T.; Lee, L.; Mambo, C.; Levine, W.; Zaidi, A.; Griffin, P. M.

    2001-01-01

    In 1992, a large outbreak of bloody diarrhea caused by Escherichia coli O157 infections occurred in southern Africa. In Swaziland, 40,912 physician visits for diarrhea in persons ages >5 years were reported during October through November 1992. This was a sevenfold increase over the same period during 1990-91. The attack rate was 42% among 778 residents we surveyed. Female gender and consuming beef and untreated water were significant risks for illness. E. coli O157:NM was recovered from seven affected foci in Swaziland and South Africa; 27 of 31 patient and environmental isolates had indistinguishable pulsed-field gel electrophoresis patterns. Compared with previous years, a fivefold increase in cattle deaths occurred in October 1992. The first heavy rains fell that same month (36 mm), following 3 months of drought. Drought, carriage of E. coli O157 by cattle, and heavy rains with contamination of surface water appear to be important factors contributing to this outbreak. PMID:11747693

  20. Escherichia coli O157:H7 Outbreak Associated with Restaurant Beef Grinding.

    PubMed

    Torso, Lauren M; Voorhees, Ronald E; Forest, Stephen A; Gordon, Andrew Z; Silvestri, Sharon A; Kissler, Bonnie; Schlackman, Jessica; Sandt, Carol H; Toma, Paul; Bachert, Joel; Mertz, Kristen J; Harrison, Lee H

    2015-07-01

    Escherichia coli O157:H7 is a common cause of foodborne illness in the United States. Beef ground at establishments regulated by the U.S. Department of Agriculture, Food Safety and Inspection Service is routinely tested for E. coli O157:H7. Prior to December 2013, boxed beef product (wholesale cuts of beef, such as beef loin, packaged into bags and boxed for shipping) was not always tested for this pathogen. Downstream processors or retailers may grind the product; and, if the ground beef is not cooked to the recommended temperature, pathogens on the exterior of the beef introduced to the interior through grinding may survive. On 18 October 2013, the Allegheny County Health Department identified two E. coli O157:H7 cases, both of whom were food handlers at restaurant A, a restaurant that ground locally produced boxed beef for hamburgers on site. Case finding was conducted through public messaging, employee surveys, and disease surveillance. All potential cases were interviewed using a standard questionnaire. A confirmed case was defined as laboratory-confirmed E. coli O157:H7 with exposure to restaurant A. A probable case was defined as a patient with compatible symptoms and exposure to restaurant A but without laboratory confirmation. All human and food isolates were characterized by pulsed-field gel electrophoresis and multilocus variable-number tandem repeat analysis. The analysis identified 14 confirmed and 10 probable cases of E. coli; 18 nonintact ground beef samples tested positive for E. coli O157:H7. Nine confirmed cases were restaurant A employees. All confirmed cases recalled eating a restaurant A hamburger in the 10 days before illness onset; most cases reported consuming medium to rare hamburgers. Multiple pulsed-field gel electrophoresis and multilocus variable-number tandem repeat analysis patterns were identified among both the human and ground beef isolates, and the patient isolates matched those found in ground beef samples. Restaurant A

  1. Colonization of 8-week-old conventionally reared goats by Escherichia coli O157 : H7 after oral inoculation.

    PubMed

    La Ragione, R M; Ahmed, N My; Best, A; Clifford, D; Weyer, U; Cooley, W A; Johnson, L; Pearson, G R; Woodward, M J

    2005-05-01

    Enterohaemorrhagic Escherichia coli O157 : H7 infections of man have been associated with consumption of unpasteurized goat's milk and direct contact with kid goats on petting farms, yet little is known about colonization of goats with this organism. To assess the contribution of flagella and intimin of E. coli O157 : H7 in colonization of the goat, 8-week-old conventionally reared goats were inoculated orally in separate experiments with 1x10(10) c.f.u. of a non-verotoxigenic strain of E. coli O157 : H7 (strain NCTC 12900 Nal(r)), an aflagellate derivative (DMB1) and an intimin-deficient derivative (DMB2). At 24 h after inoculation, the three E. coli O157 : H7 strains were shed at approximately 5x10(4) c.f.u. (g faeces)(-1) from all animals. Significantly fewer intimin-deficient bacteria were shed only on days 2 (P = 0.003) and 4 (P = 0.014), whereas from day 7 to 29 there were no differences. Tissues from three animals inoculated with wild-type E. coli O157 : H7 strain NCTC 12900 Nal(r) were sampled at 24, 48 and 96 h after inoculation and the organism was cultured from the large intestine of all three animals and from the duodenum and ileum of the animal examined at 96 h. Tissues were examined histologically but attaching-effacing (AE) lesions were not observed at any intestinal site of the animals examined at 24 or 48 h. However, the animal examined at 96 h, which had uniquely shed approximately 1x10(7) E. coli O157 : H7 (g faeces)(-1) for the preceding 3 days, showed a heavy, diffuse infection with cryptosporidia and abundant, multifocal AE lesions in the distal colon, rectum and at the recto-anal junction. These AE lesions were confirmed by immunohistochemistry to be associated with E. coli O157 : H7. PMID:15824429

  2. Strain Variation in Mycobacterium marinum Fish Isolates

    PubMed Central

    Ucko, M.; Colorni, A.; Kvitt, H.; Diamant, A.; Zlotkin, A.; Knibb, W. R.

    2002-01-01

    A molecular characterization of two Mycobacterium marinum genes, 16S rRNA and hsp65, was carried out with a total of 21 isolates from various species of fish from both marine and freshwater environments of Israel, Europe, and the Far East. The nucleotide sequences of both genes revealed that all M. marinum isolates from fish in Israel belonged to two different strains, one infecting marine (cultured and wild) fish and the other infecting freshwater (cultured) fish. A restriction enzyme map based on the nucleotide sequences of both genes confirmed the divergence of the Israeli marine isolates from the freshwater isolates and differentiated the Israeli isolates from the foreign isolates, with the exception of one of three Greek isolates from marine fish which was identical to the Israeli marine isolates. The second isolate from Greece exhibited a single base alteration in the 16S rRNA sequence, whereas the third isolate was most likely a new Mycobacterium species. Isolates from Denmark and Thailand shared high sequence homology to complete identity with reference strain ATCC 927. Combined analysis of the two gene sequences increased the detection of intraspecific variations and was thus of importance in studying the taxonomy and epidemiology of this aquatic pathogen. Whether the Israeli M. marinum strain infecting marine fish is endemic to the Red Sea and found extremely susceptible hosts in the exotic species imported for aquaculture or rather was accidentally introduced with occasional imports of fingerlings from the Mediterranean Sea could not be determined. PMID:12406715

  3. Characterization of an RTX toxin from enterohemorrhagic Escherichia coli O157:H7.

    PubMed Central

    Bauer, M E; Welch, R A

    1996-01-01

    A hemolytic determinant of enterohemorrhagic Escherichia coli O157:H7 is encoded on a 90-kbp plasmid (pO157). This enterohemorrhagic E. coli toxin (Ehx) is a newly described RTX cytotoxin. The prototype RTX toxin is the E. coli hemolysin (Hly) associated with extraintestinal E. coli infections. We expressed Ehx from E. coli K-12 strains harboring either pSK3, a pO157 derivative marked with Tn801 unlinked to Ehx, or a recombinant plasmid containing an 11.9-kbp subclone (pEO40) of pSK3. The Ehx activities and antibody reactivities were compared with those of Hly. Little Ehx was secreted extracellularly from the strain harboring pSK3; however, when the Hly transport genes hlyBD were supplied in trans, both intracellular and extracellular levels of Ehx were enhanced more than 15-fold. The strain harboring pEO40 secreted at least 140-fold more Ehx than did the strain harboring pSK3, and neither intracellular nor extracellular levels were significantly enhanced by the addition of hlyBD in trans. Polyclonal anti-HlyA antiserum and several anti-HlyA monoclonal antibodies, including the monoclonal antibody A10, which is panreactive for nearly all RTX toxins, reacted with EhxA antigen by immunoblot analysis. In hemolysis and 51Cr release assays, Ehx demonstrated similar efficiencies in lysis of BL-3 cells (cells from a bovine lymphoma cell line) and sheep and human erythrocytes. Surprisingly, it demonstrated very little activity against two human lymphoma cell lines. In contrast, Hly lysed all five cell types tested, each to a greater extent than that demonstrated by comparable amounts of Ehx. As with other RTX toxins, Ehx activity was calcium dependent and heat labile. PMID:8557336

  4. Diversity of Survival Patterns among Escherichia coli O157:H7 Genotypes Subjected to Food-Related Stress Conditions

    PubMed Central

    Elhadidy, Mohamed; Álvarez-Ordóñez, Avelino

    2016-01-01

    The purpose of this study was to evaluate the resistance patterns to food-related stresses of Shiga toxin producing Escherichia coli O157:H7 strains belonging to specific genotypes. A total of 33 E. coli O157:H7 strains were exposed to seven different stress conditions acting as potential selective pressures affecting the transmission of E. coli O157:H7 to humans through the food chain. These stress conditions included cold, oxidative, osmotic, acid, heat, freeze-thaw, and starvation stresses. The genotypes used for comparison included lineage-specific polymorphism, Shiga-toxin-encoding bacteriophage insertion sites, clade type, tir (A255T) polymorphism, Shiga toxin 2 subtype, and antiterminator Q gene allele. Bacterial resistance to different stressors was calculated by determining D-values (times required for inactivation of 90% of the bacterial population), which were then subjected to univariate and multivariate analyses. In addition, a relative stress resistance value, integrating resistance values to all tested stressors, was calculated for each bacterial strain and allowed for a ranking-type classification of E. coli O157:H7 strains according to their environmental robustness. Lineage I/II strains were found to be significantly more resistant to acid, cold, and starvation stress than lineage II strains. Similarly, tir (255T) and clade 8 encoding strains were significantly more resistant to acid, heat, cold, and starvation stress than tir (255A) and non-clade 8 strains. Principal component analysis, which allows grouping of strains with similar stress survival characteristics, separated strains of lineage I and I/II from strains of lineage II, which in general showed reduced survival abilities. Results obtained suggest that lineage I/II, tir (255T), and clade 8 strains, which have been previously reported to be more frequently associated with human disease cases, have greater multiple stress resistance than strains of other genotypes. The results from this

  5. Diversity of Survival Patterns among Escherichia coli O157:H7 Genotypes Subjected to Food-Related Stress Conditions.

    PubMed

    Elhadidy, Mohamed; Álvarez-Ordóñez, Avelino

    2016-01-01

    The purpose of this study was to evaluate the resistance patterns to food-related stresses of Shiga toxin producing Escherichia coli O157:H7 strains belonging to specific genotypes. A total of 33 E. coli O157:H7 strains were exposed to seven different stress conditions acting as potential selective pressures affecting the transmission of E. coli O157:H7 to humans through the food chain. These stress conditions included cold, oxidative, osmotic, acid, heat, freeze-thaw, and starvation stresses. The genotypes used for comparison included lineage-specific polymorphism, Shiga-toxin-encoding bacteriophage insertion sites, clade type, tir (A255T) polymorphism, Shiga toxin 2 subtype, and antiterminator Q gene allele. Bacterial resistance to different stressors was calculated by determining D-values (times required for inactivation of 90% of the bacterial population), which were then subjected to univariate and multivariate analyses. In addition, a relative stress resistance value, integrating resistance values to all tested stressors, was calculated for each bacterial strain and allowed for a ranking-type classification of E. coli O157:H7 strains according to their environmental robustness. Lineage I/II strains were found to be significantly more resistant to acid, cold, and starvation stress than lineage II strains. Similarly, tir (255T) and clade 8 encoding strains were significantly more resistant to acid, heat, cold, and starvation stress than tir (255A) and non-clade 8 strains. Principal component analysis, which allows grouping of strains with similar stress survival characteristics, separated strains of lineage I and I/II from strains of lineage II, which in general showed reduced survival abilities. Results obtained suggest that lineage I/II, tir (255T), and clade 8 strains, which have been previously reported to be more frequently associated with human disease cases, have greater multiple stress resistance than strains of other genotypes. The results from this

  6. Variation in Stress Resistance Patterns among stx Genotypes and Genetic Lineages of Shiga Toxin-Producing Escherichia coli O157

    PubMed Central

    Lee, Ken-ichi; French, Nigel P.; Jones, Geoff; Hara-Kudo, Yukiko; Iyoda, Sunao; Kobayashi, Hideki; Sugita-Konishi, Yoshiko; Tsubone, Hirokazu

    2012-01-01

    To evaluate the relationship between bacterial genotypes and stress resistance patterns, we exposed 57 strains of Shiga toxin-producing Escherichia coli (STEC) O157 to acid, freeze-thaw, heat, osmotic, oxidative, and starvation stresses. Inactivation rates were calculated in each assay and subjected to univariate and multivariate analyses, including principal component analysis (PCA) and cluster analysis. The stx genotype was determined for each strain as was the lineage-specific polymorphism assay (LSPA6) genotype. In univariate analyses, strains of the stx1 stx2 genotype showed greater resistance to heat than strains of the stx1 stx2c genotype; moreover, strains of the stx1 stx2 genotype showed greater resistance to starvation than strains of the stx2 or stx2c genotypes. LSPA6 lineage I (LI) strains showed greater resistance to heat and starvation than LSPA6 lineage II (LII) strains. PCA revealed a general trend that a strain with greater resistance to one type of stress tended to have greater resistance to other types of stresses. In cluster analysis, STEC O157 strains were grouped into stress-resistant, stress-sensitive, and intermediate clusters. In stx genotypes, all strains of the stx1 stx2 genotype were grouped with the stress-resistant cluster, whereas 72.7% (8/11) of strains of the stx1 stx2c genotype grouped with the stress-sensitive cluster. In LI strains, 77.8% (14/18) of the strains were grouped with the stress-resistant cluster, whereas 64.7% (11/17) of LII strains were grouped with the stress-sensitive cluster. These results indicate that the genotypes of STEC O157 that are frequently associated with human illness, i.e., LI or the stx1 stx2 genotype, have greater multiple stress resistance than do strains of other genotypes. PMID:22367077

  7. Virulence of an Escherichia coli O157:H7 sorbitol-positive mutant.

    PubMed Central

    Fratamico, P M; Buchanan, R L; Cooke, P H

    1993-01-01

    Virulence and pathogenicity of an Escherichia coli O157:H7 sorbitol-positive mutant were investigated with an infant rabbit animal model as well as a battery of in vitro assays. Total cell lysate protein profiles, outer membrane protein profiles, plasmid profiles, and levels of cytotoxic activity against Vero cells were similar in the wild-type and mutant strains. Both adhered to intestinal epithelial cells in culture and reacted with fluorescein isothiocyanate-labeled antiserum against E. coli O157:H7. The mutant appeared to be similar to the wild type in all respects except in its ability to ferment sorbitol. [14C]sorbitol uptake and sorbitol-6-phosphate dehydrogenase activities were notably increased in the mutant strain. Diarrhea developed in rabbits administered the wild-type strain and in those fed the sorbitol-positive mutant. There was greater bacterial attachment and mucosal damage in the cecum and large intestine than in the small intestine. Scanning electron microscopy revealed bacteria adhering as single cells and as aggregates closely associated with mucus. Mucosal lesions consisted of areas of tissue necrosis with sloughing of epithelial cells. By transmission electron microscopy, electron-dense necrotic epithelial cells were visible in areas where bacteria were present, and epithelial cell debris containing bacteria was observed between the villar luminal surfaces. Light microscopy of epithelial cells of intestinal sections of infected rabbits revealed noticeable vacuolation and spherical, pyknotic nuclei. These data indicate that the sorbitol-negative phenotype is not associated with the pathogenicity of E. coli O157:H7. Images PMID:8285715

  8. Presence and persistence of wastewater pathogen Escherichia coli O157:H7 in hydroponic reactors of treatment wetland species.

    PubMed

    VanKempen-Fryling, R J; Stein, O R; Camper, A K

    2015-01-01

    Treatment wetlands (TWs) efficiently remove many pollutants including a several log order reduction of pathogens from influent to effluent; however, there is evidence to suggest that pathogen cells are sequestered in a subsurface wetland and may remain viable months after inoculation. Escherichia coli is a common pathogen in domestic and agricultural wastewater and the O157:H7 strain causes most environmental outbreaks in the United States. To assess attachment of E. coli to the TW rhizosphere, direct measurements of E. coli levels were taken. Experiments were performed in chemostats containing either Teflon nylon as an abiotic control or roots of Carex utriculata or Schoenoplectus acutus. Flow of simulated wastewater through the chemostat was set to maintain a 2 hour residence time. The influent was inoculated with E. coli O157:H7 containing DsRed fluorescent protein. Root samples were excised and analyzed via epifluorescent microscopy. E. coli O157:H7 was detected on the root surface at 2 hours after inoculation, and were visible as single cells. Microcolonies began forming at 24 hours post-inoculation and were detected for up to 1 week post-inoculation. Image analysis determined that the number of microcolonies with >100 cells increased 1 week post-inoculation, confirming that E. coli O157:H7 is capable of growth within biofilms surrounding wetland plant roots. PMID:26114281

  9. A stable bioluminescent construct of Escherichia coli O157:H7 for hazard assessments of long-term survival in the environment.

    PubMed

    Ritchie, Jennifer M; Campbell, Graeme R; Shepherd, Jill; Beaton, Yvonne; Jones, Davey; Killham, Ken; Artz, Rebekka R E

    2003-06-01

    A chromosomally lux-marked (Tn5 luxCDABE) strain of nontoxigenic Escherichia coli O157:H7 was constructed by transposon mutagenesis and shown to have retained the O157, H7, and intimin phenotypes. The survival characteristics of this strain in the experiments performed (soil at -5, -100, and -1,500 kPa matric potential and artificial groundwater) were indistinguishable from the wild-type strain. Evaluation of potential luminescence was found to be a rapid, cheap, and quantitative measure of viable E. coli O157:H7 Tn5 luxCDABE populations in environmental samples. In the survival studies, bioluminescence of the starved populations of E. coli O157:H7 Tn5 luxCDABE could be reactivated to the original levels of light emission, suggesting that these populations remain viable and potentially infective to humans. The attributes of the construct offer a cheap and low-risk substitute to the use of verocytotoxin-producing E. coli O157:H7 in long-term survival studies. PMID:12788737

  10. THERMAL INACTIVATION OF ESCHERICHIA COLI O157:H7 IN BLADE TENDERIZED BEEF STEAKS COOKED ON A COMMERCIAL OPEN-FLAME GAS GRILL

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Beef subprimals were inoculated on the lean side with ca. 4.0 log CFU/g of a five-strain mixture of rifampicin resistant Escherichia coli O157:H7 strains and then passed once through a mechanical blade-tenderizer with the lean side facing upwards. Another set of inoculated subprimals that were not t...

  11. A COMPARATIVE HEAT INACTIVATION STUDY OF INDIGENOUS MICROFLORA IN BEEF WITH THAT OF LISTERIA MONOCYTOGENES, SALMONELLA SEROTYPES AND ESCHERICHIA COLI O157:H7

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thermal inactivation of a mixture of five strains of Listeria monocytogenes, four strains of Escherichia coli O157:H7 and eight serotypes of Salmonella was compared to that of indigenous microflora in 75% lean ground beef. Inoculated meat was packaged in bags that were completely immersed in a circ...

  12. Rapid Identification of Protein Biomarkers of E. coli O157:H7 by MALDI-TOF-TOF Mass Spectrometry and Top-Down Proteomics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We have identified six protein biomarkers from two strains of E. coli O157:H7 and one non-pathogenic E. coli strain by matrix-assisted laser desorption/ionization (MALDI) time-of-flight/time-of-flight tandem mass spectrometry (TOF/TOF-MS/MS) and top-down proteomics. Mature, intact proteins were ext...

  13. Comparison of clinical and epidemiological features of Shiga toxin-producing Escherichia coli O157 and non-O157 infections in British Columbia, 2009 to 2011

    PubMed Central

    Wang, Xuetao; Taylor, Marsha; Hoang, Linda; Ekkert, Judi; Nowakowski, Craig; Stone, Jason; Tone, Greg; Trerise, Steven; Paccagnella, Ana; Wong, Titus; Galanis, Eleni

    2013-01-01

    INTRODUCTION: Shiga toxin-producing Escherichia coli (STEC) are major foodborne agents that have the potential to cause severe enteric illnesses and large outbreaks worldwide. Several studies found non-O157 infections to be clinically milder than O157 STEC infections. OBJECTIVE: To compare the clinical and epidemiological profiles of O157 and non-O157 STEC human infections in British Columbia (BC). METHODS: All STEC cases reported in BC from 2009 to 2011 by four local health authorities were included in the study. Cases were classified according to STEC serotype based on laboratory information. Information was gathered via case interview forms. Data analysis included the χ2 test and Mann-Whitney test; P<0.05 was considered to be statistically significant. RESULTS: A total of 260 STEC cases were reported, including 154 (59.2%) O157 cases, 63 (24.2%) non-O157 cases and 43 (16.5%) STEC cases with no serotype identified. Hospitalization rate was higher and duration of hospitalization was significantly longer for O157 cases compared with non-O157 cases, but other clinical features were not significantly different. Patients with non-O157 infections were significantly more likely to have travelled outside Canada, less likely to report food exposure at social gatherings and more likely to consume bagged greens and cheese. DISCUSSION: O157 is the predominant O serotype in BC and appeared to be more clinically severe than non-O157 STEC infections. However, the true incidence and severity of non-O157 remain unknown due to our current inability to detect all non-O157 cases. The present study and the literature suggest the need to identify more predictive virulence factors because serotype does not consistently predict disease severity. PMID:24489568

  14. Occurrence and structure of cyclic Enterobacterial Common Antigen in Escherichia coli O157:H⁻.

    PubMed

    Fregolino, Eleonora; Ivanova, Radka; Lanzetta, Rosa; Molinaro, Antonio; Parrilli, Michelangelo; Paunova-Krasteva, Tsvetelina; Stoitsova, Stoyanka R; De Castro, Cristina

    2012-12-01

    Two cyclic forms of the Enterobacterial Common Antigen were isolated from Escherichia coli O157:H(-). These antigenic determinants were purified from the biomass through extensive chemical, enzymatic and chromatographic procedures whereas MALDI MS spectrometry indicated their cyclic nature with a polymerization degree of 4 or 5. The two species, denoted as ECA(CYC-4) and ECA(CYC-5), were assigned by NMR and showed no further substitution with other appendages such as acetyl groups as usually described for similar cyclic antigens from other Enterobacteriaceae. PMID:23103511

  15. Effects of environmental parameters on the dual-species biofilms formed by Escherichia coli O157:H7 and Ralstonia insidiosa, a strong biofilm producer isolated from a fresh-cut processing plant

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biofilm forming bacteria resident to food processing facilities are a food safety concern due to the potential of biofilms to harbor foodborne bacterial pathogens. When cultured together, Ralstonia insidiosa, a strong biofilm former frequently isolated from produce processing environments, has been ...

  16. Visual Detection of Enterohemorrhagic Escherichia coli O157:H7 Using Loop-Mediated Isothermal Amplification

    PubMed Central

    Ranjbar, Reza; Erfanmanesh, Maryam; Afshar, Davoud; Mohammadi, Mohsen; Ghaderi, Omar; Haghnazari, Ali

    2016-01-01

    Introduction Escherichia coli O157:H7, an important foodborne pathogen, can cause serious renal damage, which can also lead to mortality. Since a rapid and sensitive method is needed to identify this pathogenic agent, we evaluated Loop-Mediated Isothermal Amplification Assay (LAMP) to detect Escherichia coli O157:H7. Methods We used six primers that specifically identified the rfbE gene. To examine the sensitivity of the method, different dilutions were subjected to the LAMP reaction. Other bacterial strains also were investigated to determine the specificity of the test. The turbidity of the amplified products was assayed by visual detection. The amplified products were detected by addition of SYBR Green II to the reaction tubes. Results Amplification products were observed as a ladder-like pattern on the agarose gel. A white turbidity emerged in the positive tubes. Under UV light, the positive samples were green, whereas the negative samples were orange. The detection limit of the LAMP was 78 pg/tube, and this indicated that it was 100 times more sensitive than PCR for the detection of EHEC. No LAMP products were detected when template DNA of non-EHEC strains were used, suggesting high specificity of the LAMP assay. Conclusion The results indicated that the LAMP assay is a valuable diagnostic assay to identify EHEC O157:H7. In addition, the simplicity, sensitivity, specificity, and rapidity of this assay make it a useful method to diagnose pathogens in primary labs without any need for expensive equipment or specialized techniques. PMID:27504175

  17. Prevalence and characteristics of intimin-producing Escherichia coli strains isolated from healthy chickens in Korea.

    PubMed

    Oh, J-Y; Kang, M-S; An, B-K; Shin, E-G; Kim, M-J; Kim, Y-J; Kwon, Y-K

    2012-10-01

    Virulent Escherichia coli strains have commonly been associated with diarrheal illness in humans and animals. Typical enteropathogenic Escherichia coli (EPEC) with intimin gene (eaeA) and E. coli adherence factor plasmid, or atypical EPEC with only eaeA have been implicated in human cases. In the present study, we investigated the prevalence of virulence-associated genes including eaeA in the E. coli strains isolated from cloacal specimens of 184 chicken flocks in 7 provinces in Korea between 2009 and 2010. When 7 virulence genes (VT1, VT2, LT, and ST for enterotoxigenic E. coli; eaeA and bfpA for enteropathogenic E. coli; and aggR for enteroaggregative E. coli) were screened by multiplex PCR, a total of 30 E. coli strains carrying only the eaeA gene were detected from 184 flocks that were identified as atypical enteropathogenic Escherichia coli (aEPEC). The aEPEC strains were analyzed by eae subtyping, phylogenetic grouping PCR, and serotyping. Twelve (40%) of 30 aEPEC strains possessed an eae-β subtype, followed by θ (30%), ε (16.7%), and β1 (13.3%). Eight (26.7%) of 30 aEPEC strains were designated into the phylogenetic group A. Two (6.7%) and 3 (10%) aEPEC strains were classified into the phylogenetic group B2 and D, respectively. A total of 15 (50%) aEPEC strains were serotyped to groups O24, O25, O26, O71, O80, O103, and O157, and the remaining strains were nontypeable. In analyzing the genetic diversity among the 30 aEPEC isolates by the pulsed-field gel electrophoresis method with XbaI-digestion, the pulsed-field gel electrophoresis profiling produced 20 different patterns, but isolates within the same group did not show clear geographic or breed relationships. Our data indicate that healthy chickens may constitute an important natural reservoir of aEPEC strains, and suggest that transmission to humans could not be excluded. PMID:22991525

  18. Outbreak of Escherichia coli O157:H7 infections associated with nonintact blade-tenderized frozen steaks sold by door-to-door vendors.

    PubMed

    Laine, Ellen Swanson; Scheftel, Joni M; Boxrud, David J; Vought, Kevin J; Danila, Richard N; Elfering, Kevin M; Smith, Kirk E

    2005-06-01

    Steaks have not been recognized as an important vehicle of Escherichia coli O157:H7 infection. During 11 to 27 June 2003, the Minnesota Department of Health (MDH) identified four O157 infection cases with the same pulsed-field gel electrophoresis (PFGE) subtype. All four case patients consumed brand A vacuum packed frozen steaks sold by door-to-door vendors. The steaks were blade tenderized and injected with marinade (i.e., nonintact). Information from single case patients in Michigan and Kansas identified through PulseNet confirmed the outbreak. The MDH issued a press release on 27 June to warn consumers, prompting a nationwide recall of 739,000 lb (335,506 kg) of frozen beef products. The outbreak resulted in six culture-confirmed cases (including one with hemolytic uremic syndrome) and two probable cases in Minnesota and single confirmed cases in four other states. The outbreak PFGE subtype of O157 was isolated from unopened brand A bacon-wrapped fillets from five affected Minnesota households. A fillet from one affected household was partially cooked in the laboratory, and the same O157 subtype was isolated from the uncooked interior. The tenderizing and injection processes likely transferred O157 from the surface to the interior of the steaks. These processing methods create new challenges for prevention of O157 infection. Food regulatory officials should reevaluate safety issues presented by nonintact steak products, such as microbiologic hazards of processing methods, possible labeling to distinguish intact from nonintact steaks, and education of the public and commercial food establishments on the increased risk associated with undercooked nonintact steaks. Information on single cases of O157 infection in individual states identified through PulseNet can be critical in solving multistate outbreaks in a timely manner. PMID:15954707

  19. Thermal inactivation of Escherichia coli O157:H7 and non-O157 shiga toxin-producing Escherichia coli cells in mechanically tenderized veal.

    PubMed

    Luchansky, John B; Porto-Fett, Anna C S; Shoyer, Bradley A; Thippareddi, Harshavardhan; Amaya, Jesus R; Lemler, Michael

    2014-07-01

    Preflattened veal cutlets (ca. 71.5 g, ca. 0.32 cm thick) were surface inoculated with ca. 6.8 log CFU/g of a multistrain cocktail of Escherichia coli O157:H7 (ECOH) or a cocktail made of single strains of serogroups O26, O45, O103, O104, O111, O121, and O145 of Shiga toxin-producing E. coli (STEC) cells and then were mechanically tenderized by passing once through a "Sir Steak" tenderizer. For each cooking time, in each of at least three trials, three inoculated and tenderized cutlets, with and without breading, were individually cooked in 15 or 30 ml of canola oil for 0.0, 0.75, 1.0, 1.25, 1.5, 1.75, or 2.25 min per side on an electric skillet set at 191.5°C. The temperatures of the meat and of the skillet were monitored and recorded using a type J thermocouple. Regardless of the breading or volume of oil used to cook the meat, the longer the cooking times, the higher was the internal temperature of the meat, along with a greater reduction of both ECOH and STEC. The average final internal temperature of the meat at the approximate geometric center ranged from 56.8 to 93.1°C. Microbial reductions of ca. 2.0 to 6.7 log CFU/g and ca. 2.6 to 6.2 log CFU/g were achieved for ECOH and STEC, respectively. Our data also revealed no differences in thermal inactivation of ECOH relative to the volume of oil used to cook nonbreaded cutlets. However, when cooking breaded cutlets, the use of more (30 ml) compared with less (15 ml) cooking oil resulted in greater reductions in pathogen numbers. To deliver about a 5.0-log reduction of ECOH and STEC, and to achieve the recommended internal temperature of 71.1°C, it was necessary to cook mechanically tenderized veal cutlets for at least 1.5 min per side on a preheated electric skillet set at 191.5°C and containing 15 ml of cooking oil. These data also established that cooking times and temperatures effective for inactivating serotype O157:H7 strains of E. coli in tenderized veal are equally effective against the additional six

  20. Evaluation of detection methods for non-O157 Shiga toxin-producing Escherichia coli from food.

    PubMed

    Verhaegen, Bavo; Van Damme, Inge; Heyndrickx, Marc; Botteldoorn, Nadine; Elhadidy, Mohamed; Verstraete, Karen; Dierick, Katelijne; Denayer, Sarah; De Zutter, Lieven; De Reu, Koen

    2016-02-16

    Shiga toxin-producing Escherichia coli (STEC) remains a major foodborne pathogen of concern across the globe. Rapid detection and isolation of this pathogen is of great importance for public health reasons. In this study the detection and isolation of four non-O157 STEC strains (O26, O103, O111, O145) from different artificially contaminated matrices, namely ground (minced) beef, cattle carcass swab, lettuce mix and sprouted soy beans, were evaluated. Low amounts of STEC were used (0.25-1.40 cfu/g) to spike the samples. All samples were enriched in parallel in Buffered Peptone Water (BPW) and Brila broth. After enrichment, detection was performed using real-time PCR (qPCR), and isolation using two chromogenic agar media, CHROMagar™ STEC and ChromID™ EHEC. Inoculation on the agar media was performed either directly after enrichment or after the use of an acid treatment procedure. Furthermore, the use of this procedure was also tested on naturally contaminated food products, using 150 stx-positive samples. Although the qPCR Cycle Threshold (Ct) values were lower after enrichment in Brila broth, no significant differences in recovery were observed between both enrichment broths. Both agar media were equally suitable for the isolation of STEC, although a significantly higher recovery was obtained when using both agar media in parallel. For samples with a Ct value above 25, an acid treatment step prior to isolation ensured a significant improvement in the recovery of STEC due to the reduction in background microbiota. This acid treatment procedure proved especially useful for the isolation of STEC from sprouted soy bean samples. PMID:26736066

  1. Incidence of Escherichia coli O157:H7 in frozen beef patties produced over an 8-hour shiftt.

    PubMed

    Pruett, W Payton; Biela, Timothy; Lattuada, Charles P; Mrozinski, Peter M; Barbour, W Mark; Flowers, Russell S; Osborne, William; Reagan, James O; Theno, David; Cook, Victor; McNamara, Ann Marie; Rose, Bonnie

    2002-09-01

    A ground beef patty processor detected Escherichia coli O157:H7 in five production lots during routine testing with polymerase chain reaction (PCR) technology. This finding stimulated research to determine the incidence and potential entry points of the pathogen during processing. One of these lots (53,960 kg) was divided into 71 pallets (760 kg each) of food service ground beef patties. Ten cartons (19 kg each) were removed from each pallet, for a total of 710 cartons. Four patties were taken from each carton and subdivided to provide comparable samples for E. coli O157:H7 analyses by three different laboratories. Two laboratories employed different immunoassay tests, and one used PCR to screen samples. One sample set was analyzed for aerobic plate, coliform, and E coli Biotype I counts to determine if any relationship existed between these microbial groups and the incidence of E. coli O157:H7. For 73 samples, presumptive positive results for E. coli O157:H7 were obtained by one or more methods. For 48 of these 73 samples, positive results for the pathogen were culture confirmed. The largest number (29) of culture-confirmed positive E. coli O157:H7 results were detected by PCR. Most positive results were obtained during a short segment of processing. All culture-confirmed E. coli O157:H7 strains were further characterized by two genetic subtyping techniques, resulting in two to four different patterns, depending on the subtyping procedure employed. For any sample tested, the aerobic plate count was < 3.0 log CFU/g, and coliform and E. coli Biotype I counts were < or = 1.00 log CFU/g. The results of this study suggest that most positive samples were associated with a contaminated batch of raw material introduced just before the 1725- to 1844-h processing segment. These results also indicate that more aggressive sampling plans and genetic screening technologies such as PCR may be used to better detect low levels of E. coli O157:H7 in ground beef products. PMID

  2. Reduction in levels of Escherichia coli O157:H7 in apple cider by pulsed electric fields.

    PubMed

    Iu, J; Mittal, G S; Griffiths, M W

    2001-07-01

    Many studies have demonstrated that high voltage pulsed electric field (PEF) treatment has lethal effects on microorganisms including Escherichia coli O157:H7; however, the survival of this pathogen through the PEF treatment is not fully understood. Fresh apple cider samples inoculated with E. coli O157:H7 strain EC920026 were treated with 10, 20, and 30 instant charge reversal pulses at electric field strengths of 60, 70, and 80 kV/cm, at 20, 30, and 42 degrees C. To accurately evaluate the lethality of apple cider processing steps, counts were determined on tryptic soy agar (TSA) and sorbitol MacConkey agar (SMA) to estimate the number of injured and uninjured E. coli O157:H7 cells after PEF treatment. Cell death increased significantly with increased temperatures and electric field strengths. A maximum of 5.35-log10 CFU/ml (P < 0.05) reduction in cell population was achieved in samples treated with 30 pulses and 80 kV/cm at 42 degrees C. Cell injury measured by the difference between TSA and SMA counts was found to be insignificant (P > 0.05). Under extreme conditions, a 5.91-log10 CFU/ml reduction in cell population was accomplished when treating samples with 10 pulses and 90 kV/cm at 42 degrees C. PEF treatment, when combined with the addition of cinnamon or nisin, triggered cell death, resulting in a reduction in E. coli O157:H7 count of 6 to 8 log10 CFU/ml. Overall, the combination of PEF and heat treatment was demonstrated to be an effective pasteurization technique by sufficiently reducing the number of viable E. coli O157:H7 cells in fresh apple cider to meet U.S. Federal Drug Administration recommendations. PMID:11456204

  3. Changing plasmid types responsible for extended spectrum cephalosporin resistance in Escherichia coli O157:H7 in the United States, 1996–2009

    PubMed Central

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

    2015-01-01

    Escherichia coli O157 is a major cause of foodborne illness. Plasmids are genetic elements that mobilize antimicrobial resistance determinants including blaCMY β-lactamases that confer resistance to extended-spectrum cephalosporins (ESC). ESCs are important for treating a variety of infections. IncA/C plasmids are found among diverse sources, including cattle, the principal source of E. coli O157 infections in humans. IncI1 plasmids are common among E. coli and Salmonella from poultry and other avian sources. To broaden our understanding of reservoirs of blaCMY, we determined the types of plasmids carrying blaCMY among E. coli O157. From 1996 to 2009, 3742 E. coli O157 isolates were tested. Eleven (0.29%) were ceftriaxone resistant and had a blaCMY-2-containing plasmid. All four isolates submitted before 2001 and a single 2001 isolate had blaCMY encoded on IncA/C plasmids, while all five isolates submitted after 2001 and a single 2001 isolate had blaCMY carried on IncI1 plasmids. The IncI1 plasmids were ST2, ST20, and ST23. We conclude that cephalosporin resistance among E. coli O157:H7 is due to plasmid-encoded blaCMY genes and that plasmid types appear to have shifted from IncA/C to IncI1. This shift suggests either a change in plasmid type among animal reservoirs or that the organism has expanded into avian reservoirs. More analysis of human, retail meat, and food animal isolates is necessary to broaden our understanding of the antimicrobial resistance determinants of ESC resistance among E. coli O157. PMID:26478858

  4. Determination of the Thermal Inactivation Kinetics of Listeria monocytogenes, Salmonella enterica, and Escherichia coli O157:H7 and non-O157 in Buffer and a Spinach Homogenate.

    PubMed

    Monu, Emefa Angelica; Valladares, Malcond; D'Souza, Doris H; Davidson, P Michael

    2015-08-01

    Produce has been associated with a rising number of foodborne illness outbreaks. While much produce is consumed raw, some is treated with mild heat, such as blanching or cooking. The objectives of this research were to compare the thermal inactivation kinetics of Listeria monocytogenes, Salmonella enterica, Shiga toxin-producing Escherichia coli (STEC) O157:H7, and non-O157 STEC in phosphate-buffered saline (PBS; pH 7.2) and a spinach homogenate and to provide an estimate of the safety of mild heat processes for spinach. Five individual strains of S. enterica, L. monocytogenes, STEC O157:H7, and non-O157 STEC were tested in PBS in 2-ml glass vials, and cocktails of the organisms were tested in blended spinach in vacuum-sealed bags. For Listeria and Salmonella at 56 to 60°C, D-values in PBS ranged from 4.42 ± 0.94 to 0.35 ± 0.03 min and 2.11 ± 0.14 to 0.16 ± 0.03 min, respectively. D-values at 54 to 58°C were 5.18 ± 0.21 to 0.53 ± 0.04 min for STEC O157:H7 and 5.01 ± 0.60 to 0.60 ± 0.13 min for non-O157 STEC. In spinach at 56 to 60°C, Listeria D-values were 11.77 ± 2.18 to 1.22 ± 0.12 min and Salmonella D-values were 3.51 ± 0.06 to 0.47 ± 0.06 min. D-values for STEC O157:H7 and non-O157 STEC were 7.21 ± 0.17 to 1.07 ± 0.11 min and 5.57 ± 0.38 to 0.99 ± 0.07 min, respectively, at 56 to 60°C. In spinach, z-values were 4.07 ± 0.16, 4.59 ± 0.26, 4.80 ± 0.92, and 5.22 ± 0.20°C for Listeria, Salmonella, STEC O157:H7, and non-O157 STEC, respectively. Results indicated that a mild thermal treatment of blended spinach at 70°C for less than 1 min would result in a 6-log reduction of all pathogens tested. These findings may assist the food industry in the design of suitable mild thermal processes to ensure food safety. PMID:26219359

  5. Proteomic analysis of Escherichia coli O157 cultured in bovine rumen fluid

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To obtain insights into Escherichia coli O157 (O157) adaptation and survival in the bovine rumen, the first anatomical compartment encountered by this pathogen during transit through the bovine gastrointestinal tract to sites of colonization, we defined the proteome of O157 cultured in rumen fluid (...

  6. Sensitive detection of Escherichia coli O157:H7 by conventional plating techniques.

    PubMed

    Jordan, Kieran N; Maher, Matthew M

    2006-03-01

    The direct detection and estimation of concentration of Escherichia coli O157:H7 down to 1 CFU/g of cheese was achieved by conventional plating techniques. Cheese was manufactured with unpasteurized milk inoculated with E. coli O157: H7 at 34 +/- 3 CFU/ml. The numbers of E. coli O157:H7 were monitored during cheese ripening by plating on sorbitol MacConkey agar supplemented with cefixime and potassium tellurite (CT-SMAC) and on CT-O157:H7 ID medium. Using the pour plate method, E. coli O157:H7 colonies could easily be distinguished from non-O157:H7 colonies on CT-O157:H7 ID medium but not on CT-SMAC. Higher numbers of E. coli O157:H7 were detectable with O157:H7 ID medium. Latex agglutination and PCR were used to confirm the identification of typical E. coli O157:H7 colonies, and nontypical colonies as not being E. coli O157:H7. As few as 1 CFU/g of cheese could be detected. E. coli O157:H7 also was detected in deliberately contaminated milk at concentrations as low as 4 CFU/10 ml. PMID:16541707

  7. Non-O157 Shiga toxin Producing Escherichia coli in United States Beef Production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Escherichia coli O157:H7 is classified as an adulterant in U.S. beef. Its presence is rigorously monitored. However, numerous non-O157 STEC have been associated with disease. The six most common non-O157 STEC associated with disease in the U.S. have been identified by the CDC as O26, O45, O103, O...

  8. A glimpse of Escherichia coli O157:H7 survival in soils from eastern China

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Escherichia coli O157:H7 (E. coli O157:H7) is an important food-borne pathogen, which continues to be a major public health concern worldwide. It is known that E. coli O157:H7 survive in soil environment might result in the contamination of fresh produce or water source. To investigate how the soils...

  9. Proteomic analysis of Escherichia coli O157 for discovery of novel adhesins

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: Cattle are primary reservoirs of the food borne human pathogen Escherichia coli O157 (O157). Given that the complement of factors contributing to O157 adherence to epithelial cells at the recto-anal junction and other intermittent anatomical sites along the bovine gastrointestinal trac...

  10. Effect of stress on non-O157 Shiga toxin-producing Escherichia coli

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Non-O157 Shiga toxin-producing E. coli (non-O157 STEC) have emerged as important food-borne pathogens worldwide. Non-O157 STEC serogroups O26, O45, O103, O111, O121, and O145 have been declared as adulterants in beef by the USDA Food Safety and Inspection Service. While documentation is limited, tre...

  11. A new pyrosequencing assay for rapid detection and genotyping of Shiga toxin, intimin and O157-specific rfbE genes of Escherichia coli.

    PubMed

    Goji, Noriko; Mathews, Amit; Huszczynski, George; Laing, Chad R; Gannon, Victor P J; Graham, Morag R; Amoako, Kingsley K

    2015-02-01

    Shiga toxin (stx)-producing Escherichia coli (STEC) contamination in food and water is one of the most recognized concerns and a major financial burden in human hygiene control worldwide. Rapid and highly reliable methods of detecting and identifying STEC causing gastroenteric illnesses are crucial to prevent foodborne outbreaks. A number of tests have been developed and commercialized to detect STEC using molecular microbiology techniques. Most of these are designed to identify virulence factors such as Shiga toxin and intimin as well as E. coli O and H antigen serotype specific genes. In order to screen pathogenic STEC without relying on O:H serotyping, we developed a rapid detection and genotyping assay for STEC virulence genes using a PCR-pyrosequencing application. We adapted the PyroMark Q24 Pyrosequencing platform for subtyping 4 major virulence genes, Shiga toxin 1 and 2 (stx1 and stx2), intimin (eae) and O157-antigen gene cluster target rfbE, using Single Nucleotide Polymorphism (SNP) analysis. A total of 224 E. coli strains including isolates from Canadian environment, food and clinical cases were examined. Based on the multiple alignment analysis of 30-80 base nucleotide pyrogram reads, three alleles of the Shiga toxin 1a gene (stx1a) (stx1a-I, stx1a-II, stx1a-III) were identified. Results of the stx1, stx2, eae and rfbE genotyping revealed that each group of O:H serotype shares distinctive characteristics that could be associated with the virulence of each genotype. O157:H7/NM carries stx1a-II (94%), stx2a (82%), λ/γ1-eae (100%) and rfbE type-H7/NM (100%). Whereas isolates of the "Top-6" serotypes (O26, O45, O103, O111, O121, O145) had a high incidence of stx1a-I (90%) and stx2a (100%). stx1a-III (60%) was only observed in non Top-7 (Top-6 plus O157) STEC and Shigella spp. The entire assay, from extracting DNA from colonies on a plate to the generation of sequence information, can be completed in 5h. The method of profiling these 4 STEC pathogenic

  12. Interactions of Escherichia coli O157:H7, Salmonella typhimurium and Listeria monocytogenes plants cultivated in a gnotobiotic system.

    PubMed

    Jablasone, Julietta; Warriner, Keith; Griffiths, Mansel

    2005-03-01

    The growth and persistence of Escherichia coli O157:H7, Salmonella typhimurium and Listeria monocytogenes on a diverse range of plant types over extended cultivation periods was studied. When introduced on the seed of carrot, cress, lettuce, radish, spinach and tomato all the pathogens became rapidly established shortly after germination, attaining cell densities of the order of 5.5-6.5 log cfu/g. In general, Es. coli O157:H7 and L. monocytogenes became established and persisted at significantly higher levels on seedlings (9 days post-germination) than Salmonella. Es. coli O157:H7 became internalized in cress, lettuce, radish and spinach seedlings but was not recovered within the tissues of mature plants. Internalization of Salmonella was also observed in lettuce and radish but not cress or spinach seedlings. In contrast, L. monocytogenes did not internalize within seedlings but did persist on the surface of plants throughout the cultivation period. Co-inoculation of isolates recovered from the rhizosphere of plants did not significantly affect the numbers or persistence of human pathogens. The only exception was with Enterobacter cloacae, which reduced Es. coli O157:H7 Ph1 and L. monocytogenes levels by ca. 1 log cfu/g on lettuce. With the bioluminescent phenotype of Es. coli O157:H7 Ph1, it was demonstrated that the human pathogen became established on the roots of growing plants. Scanning electron micrographs of root seedlings suggested that Es. coli O157:H7 Ph1 preferentially colonized the root junctions of seedlings. It is proposed that such colonization sites enhanced the persistence of Es. coli O157:H7 on plants and facilitated internalization within developing seedlings. The results suggest that the risk associated with internalized human pathogens in salad vegetables at harvest is low. Nevertheless, the introduction of human pathogens at an early stage of plant development could enhance their persistence in the rhizosphere. The implications of the study

  13. Assessing the performance of novel software Strain Solution on automated discrimination of Escherichia coli serotypes and their mixtures using matrix-assisted laser desorption ionization-time of flight mass spectrometry.

    PubMed

    Ojima-Kato, Teruyo; Yamamoto, Naomi; Iijima, Yoshio; Tamura, Hiroto

    2015-12-01

    O157, O26, and O111 are the most important O serogroups of enterohemorrhagic Escherichia coli worldwide. Recently we reported a strategy for discriminating these serotypes from the others using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) based on the S10-spc-alpha operon gene-encoded ribosomal protein mass spectrum (S10-GERMS) method. To realize the fully automated identification of microorganisms at species- or serotype-level with the concept of S10-GERMS method, novel software named Strain Solution for MALDI-TOF MS was developed. In this study, the Strain Solution was evaluated with a total of 45 E. coli isolates including O26, O91, O103, O111, O115, O121, O128, O145, O157, O159, and untyped serotypes. The Strain Solution could accurately discriminate 92% (11/12) of O157 strains, 100% (13/13) of O26 and O111 strains from the others with three biomarkers in an automated manner. In addition, this software could identify 2 different E. coli strains (K-12 as a non-O157 representative and O157) in mixed samples. The results suggest that Strain Solution will be useful for species- or serotype-level classification of microorganisms in the fields of food safety and diagnostics. PMID:26554940

  14. Heat and drought stress during growth of lettuce (Lactuca sativa L.) does not promote internalization of Escherichia coli O157:H7.

    PubMed

    Zhang, Guodong; Ma, Li; Beuchat, Larry R; Erickson, Marilyn C; Phelan, Vanessa H; Doyle, Michael P

    2009-12-01

    Studies were done to determine the effect of heat stress on internalization of Escherichia coli O157:H7 in lettuce subjected to different watering practices during growth. Iceberg and romaine lettuce were grown in sandy soil in an environmental chamber at 23 degrees C during the day and 7 degrees C at night, with a 12-h photoperiod. Thirty days after transplanting seedlings, potting soil was inoculated with a five-strain mixture of green fluorescent protein-labeled E. coli O157:H7 at populations of 4 and 6 log CFU/g of soil. Lettuce plants were exposed to one of two temperature stress regimes: 36 degrees C during the day and 15 degrees C at night for 2 days, or 32 degrees C during the day and 15 degrees C at night for 3 days, both with a 12-h photoperiod. Control plants were held at 23 degrees C during the day and 7 degrees C at night for 3 days. Plants were either watered daily or not watered during the heat stress and control treatments. E. coli O157:H7 was detected by enrichment in all inoculated soil and rhizosphere samples from plants grown in inoculated soil. Less E. coli O157:H7 was detected in inoculated heat-stressed soil than in control soil. From inoculated pots, all leaf surfaces and macerated leaves that had been surface sanitized were negative for E. coli O157:H7. All surface-sanitized macerated roots from control samples and from 143 of 144 samples of inoculated samples were negative for E. coli O157:H7. Heat stress during growth of lettuce did not promote or enhance internalization of E. coli O157:H7, regardless of the moisture content in the soil. PMID:20003727

  15. Development of a colony lift immunoassay to facilitate rapid detection and quantification of Escherichia coli O157:H7 from agar plates and filter monitor membranes.

    PubMed

    Ingram, D T; Lamichhane, C M; Rollins, D M; Carr, L E; Mallinson, E T; Joseph, S W

    1998-07-01

    E. coli O157:H7 is a food-borne adulterant that can cause hemorrhagic ulcerative colitis and hemolytic uremic syndrome. Faced with an increasing risk of foods contaminated with E. coli O157:H7, food safety officials are seeking improved methods to detect and isolate E. coli O157:H7 in hazard analysis and critical control point systems in meat- and poultry-processing plants. A colony lift immunoassay was developed to facilitate the positive identification and quantification of E. coli O157:H7 by incorporating a simple colony lift enzyme-linked immunosorbent assay with filter monitors and traditional culture methods. Polyvinylidene difluoride (PVDF) membranes (Millipore, Bedford, Mass.) were prewet with methanol and were used to make replicates of every bacterial colony on agar plates or filter monitor membranes that were then reincubated for 15 to 18 h at 36 +/- 1 degree C, during which the colonies not only remained viable but were reestablished. The membranes were dried, blocked with blocking buffer (Kirkegaard and Perry Laboratories [KPL], Gaithersburg, Md.), and exposed for 7 min to an affinity-purified horseradish peroxidase-labeled goat anti-E. coli O157 antibody (KPL). The membranes were washed, exposed to a 3,3',5,5'-tetramethylbenzidine membrane substrate (TMB; KPL) or aminoethyl carbazole (AEC; Sigma Chemical Co., St. Louis, Mo.), rinsed in deionized water, and air dried. Colonies of E. coli O157:H7 were identified by either a blue (via TMB) or a red (via AEC) color reaction. The colored spots on the PVDF lift membrane were then matched to their respective parent colonies on the agar plates or filter monitor membranes. The colony lift immunoassay was tested with a wide range of genera in the family Enterobacteriaceae as well as different serotypes within the E. coli genus. The colony lift immunoassay provided a simple, rapid, and accurate method for confirming the presence of E. coli O157:H7 colonies isolated on filter monitors or spread plates by

  16. Further development of sample preparation and detection methods for O157 and the top 6 non-O157 STEC serogroups in cattle feces.

    PubMed

    Conrad, Cheyenne C; Stanford, Kim; McAllister, Tim A; Thomas, James; Reuter, Tim

    2014-10-01

    Shiga toxin-producing Escherichia coli (STEC) are food-borne pathogens responsible for outbreaks of human infections worldwide. Ruminant livestock harbor STEC in their intestinal tract, and through fecal contamination possess the potential to compromise the safety of food and water. As a human health safety risk, STEC detection methods on beef carcasses and trim are needed as mandated by the USDA-FSIS. In order to monitor STEC prior to harvest and human consumption, our goal was to evaluate and/or improve detection of seven STEC serogroups in cattle feces. In comparison to traditional approaches, sample processing methods in bovine feces were evaluated using a multi-factorial Latin square design which involved freezing or freeze drying feces. Autoclaved versus non-autoclaved feces were spiked with O26:H11 or O157:H7 serotypes in various dilutions and enriched for up to 6h. Each hour, enriched aliquots were compared using traditional culture methods and quantitative polymerase chain reaction (qPCR). Furthermore, a 7-serogroup multiplex PCR (mPCR) was developed to detect O26, O45, O103, O111, O121, O145 and O157 serogroups simultaneously. The diagnostic sensitivity of our mPCR assay following 6h enrichment was superior (10CFU/g across all serogroups) compared to a previously established PCR assay (10CFU/g for O26, and O103; ≥10(4)CFU/g for all other serogroups). Obtaining viable isolates appeared to be limited by the efficiency of current immunomagnetic separation (IMS) methods, which ranged from 20 to 100% effectiveness at retrieving colonies depending on serogroup. After IMS, 70 putative STEC isolates were screened for Shiga toxin and attachment genes by mPCR. Sixty-five isolates contained one or both Shiga toxin genes. PMID:25026274

  17. Shiga Toxin-Producing Escherichia coli O157, England and Wales, 1983-2012.

    PubMed

    Adams, Natalie L; Byrne, Lisa; Smith, Geraldine A; Elson, Richard; Harris, John P; Salmon, Roland; Smith, Robert; O'Brien, Sarah J; Adak, Goutam K; Jenkins, Claire

    2016-04-01

    We evaluated clinical Shiga toxin-producing Escherichia coli O157 infections in England and Wales during 1983-2012 to describe changes in microbiological and surveillance methods. A strain replacement event was captured; phage type (PT) 2 decreased to account for just 3% of cases by 2012, whereas PT8 and PT21/28 strains concurrently emerged, constituting almost two thirds of cases by 2012. Despite interventions to control and reduce transmission, incidence remained constant. However, sources of infection changed over time; outbreaks caused by contaminated meat and milk declined, suggesting that interventions aimed at reducing meat cross-contamination were effective. Petting farm and school and nursery outbreaks increased, suggesting the emergence of other modes of transmission and potentially contributing to the sustained incidence over time. Studies assessing interventions and consideration of policies and guidance should be undertaken to reduce Shiga toxin-producing E. coli O157 infections in England and Wales in line with the latest epidemiologic findings. PMID:26982243

  18. Shiga Toxin–Producing Escherichia coli O157, England and Wales, 1983–2012

    PubMed Central

    Byrne, Lisa; Smith, Geraldine A.; Elson, Richard; Harris, John P.; Salmon, Roland; Smith, Robert; O’Brien, Sarah J.; Adak, Goutam K.; Jenkins, Claire

    2016-01-01

    We evaluated clinical Shiga toxin–producing Escherichia coli O157 infections in England and Wales during 1983–2012 to describe changes in microbiological and surveillance methods. A strain replacement event was captured; phage type (PT) 2 decreased to account for just 3% of cases by 2012, whereas PT8 and PT21/28 strains concurrently emerged, constituting almost two thirds of cases by 2012. Despite interventions to control and reduce transmission, incidence remained constant. However, sources of infection changed over time; outbreaks caused by contaminated meat and milk declined, suggesting that interventions aimed at reducing meat cross-contamination were effective. Petting farm and school and nursery outbreaks increased, suggesting the emergence of other modes of transmission and potentially contributing to the sustained incidence over time. Studies assessing interventions and consideration of policies and guidance should be undertaken to reduce Shiga toxin–producing E. coli O157 infections in England and Wales in line with the latest epidemiologic findings. PMID:26982243

  19. Escherichia coli O157:H7 gene expression in the presence of catecholamine norepinephrine.

    PubMed

    Dowd, Scot E

    2007-08-01

    Various forms of host stresses (e.g. physiological, psychological) are thought to influence susceptibility to pathogenic microorganisms. Catecholamines such as norepinephrine are released into the GI environment during acute stress and may influence the infective process of bacterial pathogens associated with the GI tract. To examine the effects of norepinephrine on expression of virulence factors in Escherichia coli O157:H7, the clinical-type isolate EDL933 (ATCC 43895) was grown in serum-Standard American Petroleum Institute media in the presence or absence of norepinephrine. After 5 h of exposure to norepinephrine, treatment and control cultures (not exposed to norepinephrine) were harvested, their RNA isolated, and gene expression evaluated. There was a dramatic increase in the expression of virulence factor transcripts including stx1, stx2, and eae. Also induced were transcripts involved in iron metabolism. Conversely, there was comparative repression of iron acquisition and phage shock protein-related transcripts in the presence of norepinephrine. Novel observations from these data suggested that exposure to norepinephrine induced glutamate decarboxylase acid resistance as well as an SOS response in E. coli O157:H7. The results corroborate many of the previous findings detailed in the literature and provide new observations that could expand the scope of microbial endocrinology. PMID:17573936

  20. Interrogation of single nucleotide polymorphisms in gnd provides a novel method for molecular serogrouping of clinically important Shiga toxin producing Escherichia coli (STEC) targeted by regulation in the United States, including the "big six" non-O157 STEC and STEC O157.

    PubMed

    Elder, J R; Bugarel, M; den Bakker, H C; Loneragan, G H; Nightingale, K K

    2016-10-01

    Escherichia coli O157:H7 has frequently been associated with foodborne infections and is considered an adulterant in raw non-intact beef in the U.S. Shiga toxin-producing E. coli (STEC) belonging to serogroups O26, O45, O103, O111, O121, and O145 (known as the "big six" non-O157) were estimated to cause >70% of foodborne infections attributed to non-O157 serogroups in the U.S., as a result, these six serogroups have also been targeted by regulation in the U.S. The purpose of this study was to develop a rapid and high-throughput molecular method to group STEC isolates into seven clinically important serogroups (i.e., O157 and the "big six" non-O157 serogroups) targeted by regulation in the U.S. by interrogating single nucleotide polymorphisms (SNPs) in gnd. A collection of 195 STEC isolates, including isolates belonging to O157:H7 (n=18), O26 (n=21), O45 (n=19), O103 (n=24), O111 (n=24), O121 (n=23), O145 (n=21), and ten other STEC serogroups (n=45), was assembled and characterized by full gnd sequencing to identify informative SNPs for molecular serogrouping. A multiplex SNP typing assay was developed to interrogate twelve informative gnd SNPs by single base pair extension chemistry and used to characterize the STEC isolate collection assembled here. SNP types were assigned to each isolate by the assay and polymorphisms were confirmed with gnd sequence data. O-serogroup-specific SNP types were identified for each of the seven clinically important STEC serogroups, which allowed the differentiation of these seven STEC serogroups from other non-O157 STEC serogroups. Although serogroups of the "big six" non-O157 STEC and O157:H7 contained multiple SNP types per O-serogroup, there were no overlapping SNP types between serogroups. Our results demonstrate that molecular serogrouping of STEC isolates by interrogation of informative SNPs in gnd represents an alternative to traditional serogrouping by agglutination for rapid and high-throughput identification of clinically

  1. Farm visits and undercooked hamburgers as major risk factors for sporadic Escherichia coli O157:H7 infection: data from a case-control study in 5 FoodNet sites.

    PubMed

    Kassenborg, Heidi D; Hedberg, Craig W; Hoekstra, Michael; Evans, Mary C; Chin, Arthur E; Marcus, Ruthanne; Vugia, Duc J; Smith, Kirk; Ahuja, Shama Desai; Slutsker, Laurence; Griffin, Patricia M

    2004-04-15

    In 1996, active surveillance in 5 Foodborne Diseases Active Surveillance Network (FoodNet) sites revealed up to a 9-fold difference in Escherichia coli O157:H7 (O157) infection incidence between sites. A matched case-control study of sporadic O157 cases was conducted in these sites from March 1996 through April 1997. Case subjects were patients with non-outbreak-related diarrheal illness who had O157 isolated from their stool samples. Control subjects were healthy persons matched by age and telephone number exchange. Overall, 196 case patients and 372 controls were enrolled. O157 infections were associated with farm exposure, cattle exposure, eating a pink hamburger (both at home and away from home), eating at a table-service restaurant, using immunosuppressive medication, and obtaining beef through a private slaughter arrangement. Variations in cattle exposures may explain a part of the regional variability of O157 infection incidence. O157 control measures should focus on reducing risks associated with eating undercooked hamburger, dining at table-service restaurants, and farm exposures. PMID:15095199

  2. Detection of Escherichia coli O157:H7 in food using real-time multiplex PCR assays targeting the stx1, stx2, wzyo157, and the fliCh7 or eae genes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Real-time multiplex PCR assays were developed to detect E. coli O157:H7 in different solid and liquid foods. In each of three trials, apple cider and raw milk (25 ml), and ground beef (15% fat) and lettuce (25 g) were inoculated with 2 or 20 CFU of E. coli O157:H7 strain 380-94 (possesses the stx1a...

  3. Biofilm Formation, Virulence Gene Profiles, and Antimicrobial Resistance of Nine Serogroups of Non-O157 Shiga Toxin-Producing Escherichia coli.

    PubMed

    Wang, Jiaying; Stanford, Kim; McAllister, Tim A; Johnson, Roger P; Chen, Jinding; Hou, Hongman; Zhang, Gongliang; Niu, Yan D

    2016-06-01

    The objectives of this study were to characterize the phenotype and genotype of 36 non-O157 Shiga toxin-producing Escherichia coli (STEC) strains isolated from humans, ovines, or bovines, including the top 6 (O26, O45, O103, O111, O121, and O145) and three other serogroups implicated in serious illness (O91, O113, and O128). Biofilms were formed by all strains with intermediate to strong biofilm producers (n = 24) more common at 22°C than at 37°C (p < 0.001) and 48 and 72 h (p < 0.001) than 24 h of incubation time. Biofilm-forming potential differed by serogroup and origin with O113 and human strains exhibiting the highest potential (p < 0.001). Biofilm-associated genes, csgA/csgD/crl/fimH (100%), flu (94%), rpoS (92%), ehaA(α) (89%), and cah (72%), were most prevalent, while mlrA (22%) and ehaA(β) (14%) were least prevalent, although there was no clear compliment of genes associated with strains exhibiting the greatest biofilm-forming capacity. Among 12 virulence genes screened, iha and ehxA were present in 92% of the strains. The occurrence of stx1 in the top 6 serogroups (8/12, 67%) did not differ (p = 0.8) from other serogroups (17/24, 71%), but stx2 was less likely (confidence interval [CI] = 0.14-1.12; p = 0.04) to be in the former (9/24, 38%) than the latter (9/12, 75%). Excluding serogroups, O91 and O121, at least one strain per serogroup was resistant to between three and six antimicrobials. Streptomycin (31%), sulfisoxazole (31%), and tetracycline (25%) resistance was most common and was 35-50% less likely (p < 0.05) in human than animal strains. All non-O157 STEC strains were able to form biofilms on an abiotic surface, with some exhibiting resistance to multiple antimicrobials. Potential as a reservoir of antimicrobial resistance genes may be another hazard of biofilms in food-processing plants. As a result, future strategies to control these pathogens may include measures to prevent biofilms. PMID:27023165

  4. Internalization and fate of Escherichia coli O157:H7 in leafy green phyllosphere tissue using various spray conditions.

    PubMed

    Erickson, Marilyn C; Webb, Cathy C; Davey, Lindsey E; Payton, Alison S; Flitcroft, Ian D; Doyle, Michael P

    2014-05-01

    In the past decade, leafy greens have been implicated in several outbreaks of foodborne illness, and research has focused on contamination during preharvest operations. Concerns have been raised that internalization of pathogens into the edible tissue occurs where postharvest chemical interventions would be ineffective. This study was initiated to measure the degree and fate of Escherichia coli O157:H7 internalized in the phyllosphere tissue of leafy greens when spray conditions, inoculum level, and type of leafy green were varied. Two spraying treatments were applied: (i) spraying individual spinach or lettuce leaves on plants once with a high dose (7 to 8 log CFU/ml) of E. coli O157:H7 and (ii) spraying spinach, lettuce, or parsley plants repeatedly (once per minute) with a low dose (2.7 to 4.2 log CFU/ml) of E. coli O157:H7 over a 10- to 20-min period. With the high-dose spray protocol, no significant differences in the prevalence of internalization occurred between Shiga toxin-negative E. coli O157:H7 isolates and virulent isolates (P > 0.05), implying that the Shiga toxin virulence factors did not influence internalization or the subsequent fate of those populations under these test conditions. Significantly greater internalization of E. coli O157:H7 occurred in spinach leaves compared with lettuce leaves when leaves were sprayed once with the high-dose inoculum (P < 0.05), whereas internalization was not observed in lettuce leaves but continued to be observed in spinach and parsley leaves following repeated spraying of the low-dose inoculum. Based on these results, it is surmised that a moisture film was generated when spraying was repeated and this film assisted in the mobilization of pathogen cells to plant apertures, such as stomata. E. coli O157:H7 cells that were internalized into spinach tissue using a low-dose repeat-spray protocol were temporary residents because they were not detected 2 days later, suggesting that plant-microbe interactions may be

  5. Direct 24-hour presumptive enumeration of Escherichia coli O157:H7 in foods using hydrophobic grid membrane filter followed by serological confirmation: collaborative study.

    PubMed

    Entis, P

    1998-01-01

    Fifteen laboratories took part in a collaborative study to validate a method for enumerating Escherichia coli O157:H7. The method is based on use of a hydrophobic grid membrane filter and consists of 24 h presumptive enumeration on SD-39 Agar and serological confirmation to yield a confirmed E. coli O157:H7 count. Six food products were analyzed: pasteurized apple cider, pasteurized 2% milk, cottage cheese, cooked ground pork, raw ground beef, and frozen whole egg. The test method produced significantly higher confirmed count results than did the reference method for milk, pork, and beef. Test method results were numerically higher than but statistically equivalent to reference method results for cheese, cider, and egg. The test method produced lower repeatability and reproducibility values than did the reference method for most food/inoculation level combinations and values very similar to those of the reference method for the remaining combinations. Overall, 94% of presumptive positive isolates from the test method were confirmed serologically as E coli O157:H7, and 98% of these were also biochemically typical of E. coli O157:H7 (completed test). Corresponding rates for the reference method were 69 and 98%, respectively. On the basis of the results of this collaborative study and the precollaborative study that preceded it, it is recommended that this method be adopted official first action for enumeration of E. coli O157:H7 in meats, poultry, dairy foods, infant formula, liquid eggs, mayonnaise, and apple cider. PMID:9549075

  6. Neutralizing antibodies to Shiga toxin type 2 (Stx2) reduce colonization of mice by Stx2-expressing Escherichia coli O157:H7.

    PubMed

    Mohawk, Krystle L; Melton-Celsa, Angela R; Robinson, Cory M; O'Brien, Alison D

    2010-07-01

    Previously, we showed that the Shiga toxin type 2 (Stx2)-expressing Escherichia coli O157:H7 strain 86-24 colonized mice better than did its isogenic stx(2) negative mutant. Here, we confirmed that finding by demonstrating that Stx2 given orally to mice increased the levels of the 86-24 stx(2) mutant shed in feces. Then we assessed the impact of Stx2-neutralizing antibodies, administered passively or generated by immunization with an Stx2 toxoid, on E. coli O157:H7 colonization of mice. We found that such antibodies reduced the E. coli O157:H7 burden in infected mice and, as anticipated, also protected them from weight loss and death. PMID:20472033

  7. Screening of condensed tannins from Canadian prairie forages for anti-Escherichia coli O157:H7 with an emphasis on purple prairie clover (Dalea purpurea Vent).

    PubMed

    Wang, Y; Jin, L; Ominski, K H; He, M; Xu, Z; Krause, D O; Acharya, S N; Wittenberg, K M; Liu, X L; Stanford, K; McAllister, T A

    2013-04-01

    Tannins from forages grown (n = 10) on the Canadian prairie, as well as from Quebracho, Rhus semialata, and brown seaweed (Ascophyllum nodosum), were screened for anti-Escherichia coli O157:H7 activity against E. coli O157:H7 strain 3081 at a concentration of 400 μg/ml for each tannin type, except for brown seaweed, which was at 50 μg/ml. Growth of the bacteria was assessed by measuring the optical density at 600 nm over 24 h. Tannin from seaweed at a concentration of 50 μg/ml inhibited growth of strain 3081. Among the terrestrial forages, only condensed tannins (CT) from purple prairie clover (Dalea purpurea Vent; PPC) increased (P < 0.05) the lag time and reduced (P < 0.05) the growth rate of E. coli O157:H7. The anti-E. coli O157:H7 activity of PPC CT was further assessed by culturing E. coli strain ATCC 25922 and eight strains of E. coli O157:H7 with PPC CT at 0, 25, 50, 100, or 200 μg/ml. Selected strains were enumerated after 0, 6, and 24 h of incubation, and fatty acid composition was determined after 24 h of incubation. E. coli strain 25922 was cultured with 0, 50, or 200 μg of CT per ml and harvested during the exponential growth phase for examination by transmission electron microscopy. Increasing CT concentration linearly increased (P < 0.001) the lag times of seven strains and linearly reduced (P < 0.001) the growth rates of eight E. coli O157:H7 strains. Proportions of unsaturated fatty acids in the total fatty acids were decreased (P < 0.01) by CT at 50 μg/ml. Transmission electron microscopy showed that CT disrupted the outer membrane structure. Anti-E. coli O157:H7 activity of PPC CT at levels of up to 200 μg/ml was bacteriostatic rather than bactericidal, and the mechanism of anti-E. coli activity may involve alteration in the fatty acid composition and disruption of the outer membrane of the cell. PMID:23575115

  8. Insertion Mutagenesis of wca Reduces Acid and Heat Tolerance of Enterohemorrhagic Escherichia coli O157:H7

    PubMed Central

    Mao, Ying; Doyle, Michael P.; Chen, Jinru

    2001-01-01

    Strains of enterohemorrhagic Escherichia coli (EHEC) serotype O157:H7 produce under stress copious amounts of exopolysaccharide (EPS) composed of colanic acid (CA). Studies were performed to evaluate the association of production of CA with survival of EHEC under adverse environmental conditions. A CA-deficient mutant, M4020, was obtained from a CA-proficient parental strain, E. coli O157:H7 W6-13, by inserting a kanamycin resistance gene cassette (kan) into wcaD and wcaE, 2 of the 21 genes required for CA biosynthesis. M4020 was defective in CA production as determined from the ratio of uronic acid to protein (UA/P) of cells grown from 1 to 4 days at 25°C on minimal glucose agar (MGA), MacConkey agar, and sorbitol-MacConkey agar, and by colony morphology on MGA. The results of stress treatment revealed that M4020 was substantially less tolerant to acid (pH 4.5 and 5.5) and heat (55 and 60°C) in comparison to W6-13, indicating that CA confers on E. coli O157:H7 a protective effect from the environmental stresses of acid and heat. PMID:11371548

  9. Antimicrobial Activity of Xoconostle Pears (Opuntia matudae) against Escherichia coli O157:H7 in Laboratory Medium

    PubMed Central

    Hayek, Saeed A.; Ibrahim, Salam A.

    2012-01-01

    The objective of this study was to investigate the antimicrobial activity of xoconostle pears (Opuntia matudae) against Escherichia coli O157:H7. Xoconostle pears were sliced, blended, and centrifuged. The supernatant was then filtered using a 0.45 μm filter to obtain direct extract. Direct extract of xoconostle pears was tested against four strains of E. coli O157:H7 in brain heart infusion (BHI) laboratory medium using growth over time and agar well diffusion assays. Our results showed that direct extract of xoconostle pears had a significant (P < 0.05) inhibitory effect at 4, 6, and 8% (v/v) concentrations and complete inhibitory effect at 10% (v/v) during 8 h of incubation at 37°C. Minimum inhibitory volume (MIV) was 400 μL mL−1 (v/v) and minimum lethal volume (MLV) was 650 μL mL−1 (v/v). The inhibitory effect of xoconostle pears found to be concentration dependent and not strain dependent. Thus, xoconostle pears extract has the potential to inhibit the growth of E. coli O157:H7 and could provide a natural means of controlling pathogenic contamination, thereby mitigating food safety risks. PMID:22934117

  10. Inactivation of Escherichia coli O157:H7 in Beef Roasts Cooked in Conventional or Convection Ovens or in a Slow Cooker under Selected Conditions.

    PubMed

    Gill, C O; Devos, J; Badoni, M; Yang, X

    2016-02-01

    Inactivation of Escherichia coli O157:H7 in beef roasts cooked under selected cooking conditions was evaluated. Eye of round roasts were each inoculated at five sites in the central plane with a five-strain cocktail of E. coli O157:H7 at ca. 6.3 log CFU per site and cooked to center temperatures of 56 to 71°C in a convection oven set at 120, 140, 180, or 200°C, in a conventional oven set at 120 or 210°C, and in a slow cooker set on high or low. Prime rib roasts were each inoculated at 10 sites throughout the roast with the same E. coli O157:H7 cocktail at ca. 6.6 log CFU per site and cooked in the conventional oven set at 140 or 180°C to center temperatures of 58 to 71°C. The number of sites yielding E. coli O157:H7 after cooking decreased with increasing roast center temperature for the eye of round roasts cooked in the convection oven or in the slow cooker at a given setting, but this trend was not apparent for roasts of either type cooked in the conventional oven. Reductions of E. coli O157 in both types of roasts were generally less at the center than at other locations, particularly locations closer to the surface of the meat. When eye of round roasts were cooked to the same center temperature in the convection oven, the reduction of E. coli O157:H7 increased with increasing oven temperature up to 180°C and decreased after that. The reduction of E. coli O157:H7 in replicate roasts cooked under conditions in which the organism was not eliminated during cooking mostly differed by >1 log CFU per site. However, E. coli O157:H7 was not recovered from any of the inoculation sites when eye of round roasts were cooked to 65, 60, 60, or 63°C in the convection oven set at 120, 140, 180, and 200°C, respectively; cooked to 63 or 71°C in the conventional oven set at 120 and 210°C, respectively; or cooked to 63°C in the slow cooker set at high or low. For prime rib roasts, E. coli O157:H7 was not recovered from any of the inoculation sites in roasts cooked to 71

  11. Inhibitory effects of grape seed extract on growth, quorum sensing, and virulence factors of CDC "top-six" non-O157 Shiga toxin producing E. coli.

    PubMed

    Sheng, L; Olsen, S A; Hu, J; Yue, W; Means, W J; Zhu, M J

    2016-07-16

    Non-O157 Shiga toxin producing Escherichia coli (STECs) have become a growing concern to the food industry. Grape seed extract (GSE), a byproduct of wine industry, is abundant in polyphenols that are known to be beneficial to health. The objective of this study was to evaluate the effect of GSE on the growth, quorum sensing, and virulence factors of Centers for Disease Control and Prevention (CDC) "top-six" non-O157 STECs. Minimal inhibitory concentration (MIC) of GSE was 2mg/ml against E. coli O26:H11, and 4mg/ml against the other non-O157 STECs tested. Minimal bactericidal concentration (MBC) was the same as MIC for all six non-O157 STECs tested. At 5×10(5)CFU/ml inoculation level, 4mg/ml GSE effectively inhibited the growth of all tested strains, while 0.25-2mg/ml GSE delayed bacterial growth. At a higher inoculation level (1×10(7)CFU/ml), GSE had less efficacy against the growth of the selected six non-O157 STECs. Its impact on bacterial virulence was then assessed at this inoculation level. Autoinducer-2 (AI-2) is a universal signal molecule mediating quorum sensing (QS). GSE at concentration as low as 0.5mg/ml dramatically reduced AI-2 production of all non-O157 STECs tested, with the inhibitory effect proportional to GSE levels. Consistent with diminished QS, GSE at concentration of 0.125mg/ml caused marked reduction of swimming motility of all motile non-O157 STECs tested. In agreement, GSE treatment reduced the production of flagella protein FliC and its regulator FliA in E. coli O103:H2 and E. coli O111:H2. Furthermore, 4mg/ml GSE inhibited the production of Shiga toxin, a major virulence factor, in E. coli O103:H2 and E. coli O111:H2. In summary, GSE inhibits the growth of "top-six" non-O157 STECs at the population level relevant to food contamination. At higher initial population, GSE suppresses QS with concomitant decrease in motility, flagella protein expression and Shiga toxin production. Thus, GSE has the potential to be used in food industry to

  12. Effects of a siderophore receptor and porin proteins-based vaccination on fecal shedding of Escherichia coli O157:H7 in experimentally inoculated cattle.

    PubMed

    Thornton, A B; Thomson, D U; Loneragan, G H; Fox, J T; Burkhardt, D T; Emery, D A; Nagaraja, T G

    2009-04-01

    The efficacy of a vaccine containing outer membrane siderophore receptor and porin (SRP) proteins for reducing fecal prevalence and shedding of Escherichia coli O157:H7 was evaluated in cattle inoculated with E. coli O157:H7. Thirty calves were randomly assigned to one of two groups, and on days 1 and 21 these calves were given subcutaneous injections of either a placebo (control) or the vaccine. Blood was collected weekly to monitor the serum anti-SRP antibody titers. Two weeks after the second vaccination, calves were orally inoculated with a mixture of five strains of nalidixic acid-resistant (NalR) E. coli O157:H7. Fecal samples and rectoanal mucosal swabs were collected daily for the first 5 days and then three times each week for the following 4 weeks to determine the presence and enumerate the fecal concentration of NalR E. coli O157:H7. At necropsy on day 35, gut contents and tissue swabs were collected to determine the presence and concentration of NalR E. coli O157:H7. Vaccinated cattle had significantly higher anti-SRP antibody titers than did control cattle, with a significant treatment x week interaction (P < 0.01). Vaccination of cattle with the SRP protein tended to decrease fecal concentration (1.9 versus 1.6 log CFU/g) of NalR E. coli O157:H7 (P = 0.10). The number of calves that were fecal culture positive for E. coli O157:H7 was lower (P = 0.05) in the vaccinated group than in the control group. The E. coli O157:H7 SRP vaccine tended to reduce fecal prevalence and concentration of E. coli O157:H7 in cattle orally inoculated with NalR E. coli 0157:H7 and may be a useful prehavest intervention strategy. Future research must be conducted on natural prevalence in feedlot operations to further evaluate the efficacy of this novel vaccine. PMID:19435240

  13. Influence of oxygen availability on physiology, verocytotoxin expression and adherence of Escherichia coli O157.

    PubMed

    James, B W; Keevil, C W

    1999-01-01

    A strain of Escherichia coli serotype O157 was grown in steady state chemostat culture under aerobic, oxygen-limited and anaerobic conditions. The growth and metabolic efficiency of oxygen-limited and anaerobic cultures was impaired, with biomass yield and the molar growth yield for glucose, Yglucose, reduced markedly in comparison with aerobic cultures. Steady state cells were typically short rods 2-3 microns long, and were encapsulated by a layer of extracellular material. The majority of cells were non-flagellated and fimbriae were not observed. Chemostat-grown cells were significantly more adhesive for HEp-2 monolayers than cells grown in aerobic batch culture. Furthermore, oxygen-limited and anaerobic cultures were significantly more adhesive for Hep-2 cells when compared with cells grown in aerobic chemostat culture, possibly reflecting increased pathogenicity associated with the induction of novel adhesins. Type 1 pili were not responsible for increased adherence. Verocytotoxins, VT1 and VT2, were expressed constitutively and were not influenced by oxygen availability. This study demonstrates that E. coli O157 is a versatile micro-organism, which responds to environmental conditions likely to be encountered during infection by inducing a phenotype which is more adhesive for human epithelial cells. PMID:10030015

  14. Fate of surface inoculated Escherichia coli O157:H7, Listeria monocytogenes and Salmonella Typhimurium on kippered beef during extended storage at refrigeration and abusive temperatures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The behavior of Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella Typhimurium was evaluated on kippered beef. Individual pieces of the product were separately inoculated on the top and bottom surfaces with each 3- to 5-strain pathogen cocktail at ca. 6.0 log10 CFU/piece and stored at...

  15. Non-labeled quantitative proteomic comparison identifies differences in acid resistance between Escherichia coli O157:H7 curli production variants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To understand the nature and capability of a bacterial strain to tolerate environmental conditions it is necessary to be able to identify and measure the proteins that they are expressing in any given situation. In this research, the entire protein complements produced by Escherichia coli O157:H7 s...

  16. Thermal Destruction of Escherichia coli O157:H7 in Sous-vide Cooked Ground Beef as affected by Tea Leaf and Apple Skin Powders

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We investigated the heat resistance of a four-strain mixture of Escherichia coli O157:H7 in raw ground beef in both the absence and presence of white and green tea powders and an apple skin extract. Inoculated meat, packaged in bags, was completely immersed in a circulating water bath and cooked fo...

  17. Fate of E. coli O157:H7, Salmonella spp. and potential surrogate bacteria on apricot fruit following UV-C light

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Some soft fruit, such as tree-ripened apricots, cannot be washed with aqueous sanitizers, due to their innate softness and delicate surfaces. In this study, ultraviolet-C (UV-C) light was investigated for its efficacy in inactivating 4-5 individual strains of Escherichia coli O157:H7 and Salmonella...

  18. Evaluation of a Direct-Fed Microbial Product Effect on the Prevalence and Load of Escherichia coli O157:H7 in Feedlot Cattle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Direct fed microbials (DFM) have been identified as potential pre-harvest interventions for the reduction of foodborne bacterial pathogens such as E. coli O157:H7. This study evaluated the efficacy of a direct fed microbial (DFM) consisting of Bacillus subtilis strain 166 as an antimicrobial interve...

  19. Prophage insertions in mlrA are not the major obstacle to biofilm formation in Escherichia coli O157:H7

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: Although a curli and biofilm expressing phenotype can be induced in Escherichia coli serotype O157:H7, strains examined under laboratory conditions are almost exclusively biofilm deficient and the reason for these deficiencies have remained elusive. CsgD, the central biofilm regulator, i...

  20. Inactivation of Salmonella, Escherichia coli O157:H7 and non-O157 STEC by hypochlorite solutions with high organic loads

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Introduction: Salmonella, E. coli O157:H7 and Non-O157 STEC have been recognized as foodborne pathogen concerns for fresh produce. Although chlorinated water (CW) is widely used in fresh produce processing to reduce pathogens and prevent cross-contamination, limited information is available on effic...

  1. Distribution of Shiga-Toxigenic Escherichia coli O157 in the Gastrointestinal Tract of Naturally O157-Shedding Cattle at Necropsy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Shiga-toxigenic Escherichia coli O157 (STEC O157) occurrence was determined along the entire gastrointestinal tract (GIT) of four naturally-infected cattle and at specific locations for 61 additional animals. STECO157 was recovered along the entire length of the GIT, though inter-animal distributio...

  2. Inactivation of Shiga toxin-producing O157:H7 and non-O157:H7 Escherichia coli in brine-injected, gas-grilled steaks

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We quantified translocation of Escherichia coli O157:H7 (ECOH) and non-O157:H7 verocytotoxigenic E. coli (STEC) into beef subprimals following chemical tenderization and subsequently monitored their viability after cooking steaks cut therefrom. Beef subprimals were inoculated on the lean side with c...

  3. Antimicrobial resistance in Escherichia coli O157 and non-O157 recovered from feces of domestic farm animals in Northwestern Mexico

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Antimicrobial resistance in Shiga toxin-producing Escherichia coli (STEC) O157 and non-O157 is a matter of increasing concern. Inappropriate antimicrobial use in human and animal therapy has been associated with an acquired resistance in enteric microorganisms. The aim of the present study was to de...

  4. Bacterial Communities Associated with Shiga-Toxigenic E. coli O157:H7 (STEC O157) in Beef Cattle Feedlot Environments

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: The life cycle of Shiga-toxigenic E. coli O157:H7 (STEC O157) in beef cattle feedlots involves two habitats: the warm, nutrient rich primary habitat of the lower gastrointestinal tract of cattle and the generally cool, nutrient limiting secondary habitat outside of the animal, including...

  5. High Temperature in Combination with UV Irradiation Enhances Horizontal Transfer of stx2 Gene from E. coli O157:H7 to Non-Pathogenic E. coli

    PubMed Central

    Yue, Wan-Fu; Du, Min; Zhu, Mei-Jun

    2012-01-01

    Background Shiga toxin (stx) genes have been transferred to numerous bacteria, one of which is E. coli O157:H7. It is a common belief that stx gene is transferred by bacteriophages, because stx genes are located on lambdoid prophages in the E. coli O157:H7 genome. Both E. coli O157:H7 and non-pathogenic E. coli are highly enriched in cattle feedlots. We hypothesized that strong UV radiation in combination with high temperature accelerates stx gene transfer into non-pathogenic E. coli in feedlots. Methodology/Principal Findings E. coli O157:H7 EDL933 strain were subjected to different UV irradiation (0 or 0.5 kJ/m2) combination with different temperature (22, 28, 30, 32, and 37°C) treatments, and the activation of lambdoid prophages was analyzed by plaque forming unit while induction of Stx2 prophages was quantified by quantitative real-time PCR. Data showed that lambdoid prophages in E. coli O157:H7, including phages carrying stx2, were activated under UV radiation, a process enhanced by elevated temperature. Consistently, western blotting analysis indicated that the production of Shiga toxin 2 was also dramatically increased by UV irradiation and high temperature. In situ colony hybridization screening indicated that these activated Stx2 prophages were capable of converting laboratory strain of E. coli K12 into new Shiga toxigenic E. coli, which were further confirmed by PCR and ELISA analysis. Conclusions/Significance These data implicate that high environmental temperature in combination with UV irradiation accelerates the spread of stx genes through enhancing Stx prophage induction and Stx phage mediated gene transfer. Cattle feedlot sludge are teemed with E. coli O157:H7 and non-pathogenic E. coli, and is frequently exposed to UV radiation via sunlight, which may contribute to the rapid spread of stx gene to non-pathogenic E. coli and diversity of shiga toxin producing E. coli. PMID:22347461

  6. Evaluation of culture- and PCR-based detection methods for Escherichia coli O157:H7 in inoculated ground beeft.

    PubMed

    Arthur, Terrance M; Bosilevac, Joseph M; Nou, Xiangwu; Koohmaraie, Mohammad

    2005-08-01

    Currently, several beef processors employ test-and-hold systems for increased quality control of ground beef. In such programs, each lot of product must be tested and found negative for Escherichia coli O157:H7 prior to release of the product into commerce. Optimization of three testing attributes (detection time, specificity, and sensitivity) is critical to the success of such strategies. Because ground beef is a highly perishable product, the testing methodology used must be as rapid as possible. The test also must have a low false-positive result rate so product is not needlessly discarded. False-negative results cannot be tolerated because they would allow contaminated product to be released and potentially cause disease. In this study, two culture-based and three PCR-based methods for detecting E. coli O157:H7 in ground beef were compared for their abilities to meet the above criteria. Ground beef samples were individually spiked with five genetically distinct strains of E. coli O157: H7 at concentrations of 17 and 1.7 CFU/65 g and then subjected to the various testing methodologies. There was no difference (P > 0.05) in the abilities of the PCR-based methods to detect E. coli O157:H7 inoculated in ground beef at 1.7 CFU/65 g. The culture-based systems detected more positive samples than did the PCR-based systems, but the detection times (21 to 48 h) were at least 9 h longer than those for the PCR-based methods (7.5 to 12 h). Ground beef samples were also spiked with potentially cross-reactive strains. The PCR-based systems that employed an immunomagnetic separation step prior to detection produced fewer false-positive results. PMID:21132961

  7. Crystal Diagnostics Xpress™ E7 STEC Kit for the Rapid Multiplex Detection of E. coli O157 and non-O157 Shiga toxin-producing E. coli.

    PubMed

    Zhao, Weidong; Stumpf, Curtis H; Bullard, Brian; Kuzenko, Stephanie; Niehaus, Gary D

    2015-01-01

    The Crystal Diagnostics (CDx) Xpress E7 STEC kit is a rapid and sensitive detection assay for the detection of Escherichia coli O157 and six non-O157 Shiga toxin-producing E. coli (serogroups O26, O45, O1O3, O111, O121, and O145, collectively referred to as STEC) at 1 CFU/325 g of raw ground beef and raw beef trim, or 200 g of spinach. The system comprises an automatic Crystal Diagnostics Xpress System Reader that integrates immunochemical and optical processes for the liquid crystal-based detection of microorganisms, a CDx BioCassette that incorporates antibody-coupled microspheres and liquid crystal for selective identification of the intended microbe, and additional commercially available components. The Crystal Diagnostics Xpress System(TM) combines proprietary liquid crystal technology with antibody-coated paramagnetic microspheres to selectively capture and detect STEC from food matrixes. The Xpress System expeditiously (9.5 h enrichment) provides the sensitivity and specificity of the U. S. Department of Agriculture Food Safety and Inspection Service and the U. S. Food and Drug Administration reference methods in screening as low as 1 STEC CFU/test portion. The inclusivity validation demonstrated detection of 53 of 54 STEC test strains. Shelf life testing of the antibody-coated microspheres and other Crystal Diagnostic consumables indicated that all materials were stable for a minimum of 3 months (ongoing), and lot-to-lot testing demonstrated consistent results between lots (data not shown). The internal and independent laboratory tests demonstrate that the method is rapid and sensitive for screening of the target STEC. PMID:26651567

  8. Antimicrobial interventions for O157:H7 and non-O157 Shiga toxin-producing Escherichia coli on beef subprimal and mechanically tenderized steaks.

    PubMed

    Liao, Yen-Te; Brooks, J Chance; Martin, Jennifer N; Echeverry, Alejandro; Loneragan, Guy H; Brashears, Mindy M

    2015-03-01

    Non-O157 Shiga toxin-producing Escherichia coli (STEC) is an emerging risk for food safety. Although numerous postharvest antimicrobial interventions have been effectively used to control E. coli O157:H7 during beef harvesting, research regarding their effectiveness against non-O157 STEC is scarce. The objectives of this study were (i) to evaluate effects of the spray treatments-ambient water, 5% lactic acid (LA), 200 ppm of hypobromous acid (HA), and 200 ppm of peroxyacetic acid (PA)-on the reduction of O157:H7 or non-O157 STEC (O26, O103, O111, and O145) with high (10(6) log CFU/50 cm(2)) or low (10(2) log CFU/50 cm(2)) levels on beef subprimals after vacuum storage for 14 days and (ii) to evaluate the association of the antimicrobial treatments and cooking (50 or 70°C) on the reduction of the pathogens in blade-tenderized steaks. The treatment effects were only observed (P = 0.012) on samples taken immediately after spray intervention treatment following inoculation with a high level of O157:H7. The LA and PA treatments significantly reduced low-inoculated non-O157 STEC after spray intervention; further, the LA and HA treatments resulted in significant reductions of non-O157 STEC on the low-inoculated samples after storage. Although cooking effectively reduced the detection of pathogens in internal steak samples, internalized E. coli O157:H7 and non-O157 STEC were able to survive in steaks cooked to a medium degree of doneness (70°C). This study indicated that the reduction on surface populations was not sufficient enough to eliminate the pathogen's detection following vacuum storage, mechanical tenderization, and cooking. Nevertheless, the findings of this study emphasize the necessity for a multihurdle approach and further investigations of factors that may influence thermal tolerance of internalized pathogenic STEC. PMID:25719874

  9. Predicting the presence of non-O157 Shiga toxin-producing Escherichia coli in ground beef by using molecular tests for Shiga toxins, intimin, and O serogroups

    Technology Transfer Automated Retrieval System (TEKTRAN)

    When 3,972 ground beef enrichments with 6 confirmed to contain a non-O157 Shiga toxin-producing intimin-positive Escherichia coli isolate were tested for Shiga toxin, intimin, and O group (O26,045, O103, O111, O121, and O145) genes, 183 potential positives and only 2 of the 6 confirmed positives wer...

  10. Short communication: Behavior of different Shiga toxin-producing Escherichia coli serotypes (O26:H11, O103:H2, O145:H28, O157:H7) during the manufacture, ripening, and storage of a white mold cheese.

    PubMed

    Miszczycha, S D; Bel, N; Gay-Perret, P; Michel, V; Montel, M C; Sergentet-Thevenot, D

    2016-07-01

    Ruminants are healthy carriers of Shiga toxin-producing Escherichia coli (STEC). If good hygienic and agricultural practices at the farm level, especially during the milking process, are not adequately followed, milk and dairy products made with raw milk could become contaminated. Sporadic cases and rare food outbreaks have been linked with dairy products. Consequently, understanding STEC behavior in cheeses would help to evaluate risks for human health. The behavior of 4 different STEC strains belonging to the serotypes O26:H11, O103:H2, O145:H28, and O157:H7 were monitored during the manufacture, ripening, and storage of a white mold soft cheese. These strains, originating from dairy products, were inoculated individually in raw milk from cow at 10(2) cfu/mL. During the first 24 to 36h of the manufacturing stage, the STEC level increased by 2 to 3 log10 cfu/g. Over the course of the ripening stage, the concentration of the non-O157 STEC remained relatively constant, whereas a decrease of the E. coli O157:H7 concentration was observed. During the storage stage, the level of the different non-O157 STEC strains decreased slowly in the core and in the rind of cheeses. The non-O157 STEC level reached between 3.1 and 4.1 log10 cfu/g at d 56. Interestingly, the concentration of the E. coli O157:H7 strain decreased dramatically: the strains remained detectable only after enrichment. During ripening and storage, STEC levels were generally higher in rinds than in cheese cores. In contrast to what was seen in cheese cores, the E. coli O157:H7 strain remained enumerable in rinds during these steps. These results highlight that STEC can grow during the manufacture and survive during the ripening and storage of a white mold soft cheese. PMID:27157567

  11. Predicting behavior of Staphylococcus aureus, salmonella serovars, and Escherichia coli O157: H7 in pork products during single and repeated temperature abuse periods.

    PubMed

    Ingham, Steven C; Vang, Song; Levey, Ben; Fahey, Lisa; Norback, John P; Fanslau, Melody A; Senecal, Andre G; Burnham, Greg M; Ingham, Barbara H

    2009-10-01

    Tools for predicting growth of Staphylococcus aureus, Salmonella, and Escherichia coli O157:H7 (THERM; temperature history evaluation for raw meats) have been developed using ground pork and sausage. THERM tools have been tested with three types of pork sausage but not with other pork products or during sequential temperature abuse periods. We conducted inoculation studies (five strains each of S. aureus and/or Salmonella plus E. coli O157:H7) with simulated cooling of warm sausages, inprocess warming of bratwurst, isothermal temperature abuse of pork frankfurter batter, and two sequential periods of 13, 15.6, or 21.1 degrees C temperature abuse of breakfast sausage, natural (additive-free) chops, and enhanced (phosphate solution-injected) loins. In sequential temperature abuse studies, a temperature abuse period (> or =24 h) occurred before and after either refrigeration (5 degrees C for 24 h), or freezing (-20 degrees C for 24 h) and thawing (24 h at 5 degrees C). Pathogen growth predictions from THERM developed using ground pork and sausage were compared with experimental results of 0 to 3.0 log CFU of growth. Across all temperature abuse conditions, qualitative predictions (growth versus no growth) made using the pork tool (n = 133) and the sausage tool (n = 115) were accurate (51 and 50%, respectively), fail-safe (44 and 50%), or fail-dangerous (5 and 0%). Quantitative predictions from the two tools were accurate (29 and 22% , respectively), fail-safe (59 and 73%), or fail-dangerous (12 and 5%). Pathogen growth was greater during the second sequential temperature abuse period but not significantly so (P > 0.05). Both THERM tools provide useful qualitative predictions of pathogen growth in pork products during isolated or sequential temperature abuse events. PMID:19833035

  12. A highly specific and sensitive loop-mediated isothermal amplification method for the detection of Escherichia coli O157:H7.

    PubMed

    Ravan, Hadi; Amandadi, Mojdeh; Sanadgol, Nima

    2016-02-01

    E. coli O157:H7 is one of the most important foodborne pathogen that causes some human illnesses such as bloody diarrhea, hemolytic-uremic syndrome, and kidney failure. We developed a loop-mediated isothermal amplification (LAMP) assay with six special primers that target a highly specific 299-bp region of the Z3276 gene for the detection of E. coli O157:H7. Among 117 bacterial strains tested in this study, positive results were only obtained from E. coli O157:H7 strains. The sensitivity level of the Z3276-LAMP assay was determined to be 5 CFU/reaction tube in pure bacterial culture. Moreover, the LAMP assay was successfully applied to artificially contaminated ground beef with a sensitivity level of 10(3) CFU/mL without pre-enrichment and 10 CFU/mL after a 4-h pre-enrichment. In conclusion, the present LAMP assay would be a useful and powerful tool for the rapid, sensitive, and specific diagnosis of E. coli O157:H7 strains in resource limited laboratories. PMID:26724736

  13. A Multiple Protocol to Improve Diagnosis and Isolation of Shiga Toxin-Producing Escherichia coli (STEC) from Human Stool Specimens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many enterohemorrhaegic colitis infections caused by Shiga toxin-producing are undiagnosed, particularly those belonging to non-O157 STEC serogroups. We evaluated the use of a multiple protocol approach to improve diagnosis, isolation and characterization of STEC strains from human stool specimens....

  14. Antibacterial activities of semipurified fractions of Quercus infectoria against enterohemorrhagic Escherichia coli O157:H7 and its verocytotoxin production.

    PubMed

    Voravuthikunchai, Supayang Piyawan; Suwalak, Sakol

    2008-06-01

    Escherichia coli O157:H7 is one of the most important foodborne pathogens, causing nonbloody and bloody diarrhea, hemorrhagic colitis, and hemolytic uremic syndrome. Use of antibiotics has been demonstrated to result in increased levels of verocytotoxin (VT) production as well as antibiotic resistance. Quercus infectoria was investigated for its antibacterial activity against E. coli O157:H7 and other VT-producing enterohemorrhagic E. coli (VTEC). The MIC was determined by a broth microdilution method, and the MBC was assessed by subculturing the bacteria from the wells that showed no apparent growth onto Mueller-Hinton agar. The fractions Qi2, Qi3, and Qi4 of Q. infectoria were demonstrated to possess good antibacterial activity, with MICs and MBCs ranging from 250 to 500 microg/ml. The effect of the effective fraction, Qi4, on the production of VT was determined using a reversed passive latex agglutination. The results indicate that at 20 h, fraction Qi4 markedly inhibits the release of VT1 and VT2 from VTEC cells at both inhibitory and subinhibitory concentrations. Furthermore, verotoxicity assay demonstrated that bacterial cultures treated with fraction Qi4 exerted less toxic effect on Vero cells. These in vitro results clearly indicate that the fraction Qi4 might constitute a promising natural food additive for the control of food poisoning by E. coli O157:H7 as well as other VTEC strains. PMID:18592749

  15. Stx1 prophage excision in Escherichia coli strain PA20 confers strong curli and biofilm formation by restoring native mlrA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Prophage insertions in Escherichia coli O157:H7 mlrA contribute to the low expression of curli fimbriae and biofilm observed in many clinical isolates. Varying levels of CsgD-dependent curli/biofilm expression are restored to strains bearing prophage insertions in mlrA by mutation of regulatory gene...

  16. Effects of vegetable type, package atmosphere and storage temperature on growth and survival of Escherichia coli O157:H7 and Listeria monocytogenes.

    PubMed

    Francis, G A; O'Beirne, D

    2001-08-01

    The survival and growth of Escherichia coli O157:H7 (ATCC 43888 and NCTC 12900) and Listeria monocytogenes (ATCC 19114 and NCTC 11994) during storage (4 and 8 degrees C) on ready-to-use (RTU) packaged vegetables (lettuce, swedes (rutabaga), dry coleslaw mix, soybean sprouts) were studied. The vegetables were sealed within oriented polypropylene packaging film, and modified atmospheres developed in packs during storage due to produce respiration. Survival and growth patterns were dependent on vegetable type, package atmosphere, storage temperature and bacterial strain. Populations of L. monocytogenes and E. coli O157:H7 increased (P<0.05, by 1.5 to 2.5 log cycles, depending on strain) during a 12-day storage period on shredded lettuce (8 degrees C). L. monocytogenes populations also increased (by approximately 1 log cycle) on packaged swedes, did not change significantly (P>0.05) in packages of soybean sprouts and decreased by approximately 1.5 log cycles (P<0.05) on coleslaw mix (8 degrees C). E. coli O157:H7 populations on packaged coleslaw and soybean sprouts increased (by 1.5 to 2.5 log cycles) up to day 5, but declined during subsequent storage (8 degrees C). On packaged swedes (8 degrees C), populations of E. coli O157:H7 strain ATCC 43888 increased (by approximately 1 log cycle) during storage, whereas populations of strain 12900 increased between days 2 and 5, and declined during subsequent storage. Reducing the storage temperature from 8 to 4 degrees C reduced the growth of L. monocytogenes and E. coli O157:H7 on packaged RTU vegetables. However, viable populations remained at the end of the storage period at 4 degrees C. PMID:11641769

  17. Nationwide prevalence and risk factors for faecal carriage of Escherichia coli O157 and O26 in very young calves and adult cattle at slaughter in New Zealand.

    PubMed

    Jaros, P; Cookson, A L; Reynolds, A; Prattley, D J; Campbell, D M; Hathaway, S; French, N P

    2016-06-01

    Nationwide prevalence and risk factors for faecal carriage of Escherichia coli O157 and O26 in cattle were assessed in a 2-year cross-sectional study at four large slaughter plants in New Zealand. Recto-anal mucosal swab samples from a total of 695 young (aged 4-7 days) calves and 895 adult cattle were collected post-slaughter and screened with real-time polymerase chain reaction (PCR) for the presence of E. coli O157 and O26 [Shiga toxin-producing E. coli (STEC) and non-STEC]. Co-infection with either serogroup of E. coli (O157 or O26) was identified as a risk factor in both calves and adult cattle for being tested real-time PCR-positive for E. coli O157 or O26. As confirmed by culture isolation and molecular analysis, the overall prevalence of STEC (STEC O157 and STEC O26 combined) was significantly higher in calves [6·0% (42/695), 95% confidence interval (CI) 4·4-8·1] than in adult cattle [1·8% (16/895), 95% CI 1·1-3·0] (P < 0·001). This study is the first of its kind in New Zealand to assess the relative importance of cattle as a reservoir of STEC O157 and O26 at a national level. Epidemiological data collected will be used in the development of a risk management strategy for STEC in New Zealand. PMID:26733155

  18. Risk factors for sporadic Shiga toxin-producing Escherichia coli O157 and non-O157 illness in The Netherlands, 2008-2012, using periodically surveyed controls.

    PubMed

    Friesema, I H M; Schotsborg, M; Heck, M E O C; Van Pelt, W

    2015-05-01

    Shiga toxin-producing Escherichia coli (STEC) infections have been associated with severe illness. Ruminants are seen as the main reservoir and the major transmission route is considered to be foodborne. In The Netherlands, a case-control study was conducted, using data collected during 2008-2012. Patients were interviewed and controls completed a self-administered questionnaire. Patients travelling abroad were excluded from the analyses. STEC O157 and non-O157 were examined separately and differentiated into two age groups (<10 years, ⩾10 years). We included 130 O157 cases, 78 non-O157 cases and 1563 controls. In both age groups of O157 patients, raw spreadable sausage was the main risk factor for infection. For STEC non-O157 cases aged <10 years, contact with farm animals was the main risk factor and in non-O157 cases aged ⩾10 years, consumption of beef was the main risk factor. During 2008-2012, risk factors for STEC infections in the Dutch population differed between age groups and serogroup categories, and were related to eating meat and contact with farm animals. Advising the public about the risks of consuming raw or undercooked meat (products) and hygiene habits in case of contact with farm animals, could help in the prevention of STEC infections. PMID:25195737

  19. Multiplex Real-Time PCR Assays for Screening of Shiga Toxin 1 and 2 Genes, Including All Known Subtypes, and Escherichia coli O26-, O111-, and O157-Specific Genes in Beef and Sprout Enrichment Cultures.

    PubMed

    Harada, Tetsuya; Iguchi, Atsushi; Iyoda, Sunao; Seto, Kazuko; Taguchi, Masumi; Kumeda, Yuko

    2015-10-01

    Shiga toxin family members have recently been classified using a new nomenclature into three Stx1 subtypes (Stx1a, Stx1c, and Stx1d) and seven Stx2 subtypes (Stx2a, Stx2b, Stx2c, Stx2d, Stx2e, Stx2f, and Stx2g). To develop screening methods for Stx genes, including all of these subtype genes, and Escherichia coli O26-, O111-, and O157-specific genes in laboratory investigations of Shiga toxin-producing E. coli (STEC) foodborne cases, we developed multiplex real-time PCR assays and evaluated their specificity and quantitative accuracy using STEC and non-STEC isolates, recombinant plasmids, and food enrichment cultures and by performing STEC spiking experiments with beef and sprout enrichment cultures. In addition, we evaluated the relationship between the recovery rates of the target strains by direct plating and immunomagnetic separation and the cycle threshold (CT) values of the real-time PCR assays for the Stx subtypes and STEC O26, O111, and O157 serogroups. All three stx1- and seven stx2-subtype genes were detected by real-time PCR with high sensitivity and specificity, and the quantitative accuracy of this assay was confirmed using control plasmids and STEC spiking experiments. The results of the STEC spiking experiments suggest that it is not routinely possible to isolate STEC from enrichment cultures with real-time PCR CT values greater than 30 by direct plating on MacConkey agar, although highly selective media and immunomagnetic beads were able to isolate the inoculated strains from the enrichment cultures. These data suggest that CT values obtained from the highly quantitative real-time PCR assays developed in this study provide useful information to develop effective isolation strategies for STEC from food samples. The real-time PCR assays developed here are expected to aid in investigations of infections or outbreaks caused by STEC harboring any of the stx-subtype genes in the new Stx nomenclature, as well as STEC O26, O111, and O157. PMID:26408128

  20. Isolation and Purification of Enteroicin E-760 with a Broad Antimicrobial Activity Against Gram-positive and Gram-negative Bacteria (AAC01569-06 Version 3)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Strain NRRL B-30745, isolated from chicken ceca, and identified as an Enterococcus spp. of the durans/faecium/hirae group, produces a 5362 Da bacteriocin that inhibits the growth of Salmonella enteritidis, S. choleraesuis, S. typhimurium, S. gallinarum, Escherichia coli O157:H7, Yersinia enterocolit...

  1. An outbreak of Escherichia coli O157:H7 infections and haemolytic uraemic syndrome associated with consumption of unpasteurized apple cider.

    PubMed

    Hilborn, E D; Mshar, P A; Fiorentino, T R; Dembek, Z F; Barrett, T J; Howard, R T; Cartter, M L

    2000-02-01

    During October 1996, an outbreak of Escherichia coli O157:H7 infections among Connecticut residents occurred. An epidemiologic investigation included enhanced surveillance and a case-control study. Clinical isolates of Escherichia coli O157:H7 were typed by pulsed-field gel electrophoresis (PFGE). Implicated cider samples were analysed by culture and polymerase chain reaction (PCR). Consumption of implicated cider was associated with illness; (matched odds ratio = undefined, 95 % confidence interval = 3.5-infinity). Ultimately, a total of 14 outbreak-associated patients were identified. All isolates analysed by PFGE yielded the outbreak-associated subtype. Escherichia coli O157:H7 was not cultured from three cider samples; PCR analysis detected DNA fragments consistent with Escherichia coli O157:H7 in one. This outbreak was associated with drinking one brand of unpasteurized apple cider. PFGE subtyping supported the epidemiologic association. PCR analysis detected microbial contaminants in the absence of live organisms. Washing and brushing apples did not prevent cider contamination. PMID:10722127

  2. Spatial epidemiology of Escherichia coli O157:H7 in dairy cattle in relation to night roosts Of Sturnus vulgaris (European Starling) in Ohio, USA (2007-2009).

    PubMed

    Swirski, A L; Pearl, D L; Williams, M L; Homan, H J; Linz, G M; Cernicchiaro, N; LeJeune, J T

    2014-09-01

    The goal of our study was to use spatial scan statics to determine whether the night roosts of European starlings (Sturnus vulgaris) act as point sources for the dissemination of Escherichia coli O157:H7 among dairy farms. From 2007 to 2009, we collected bovine faecal samples (n = 9000) and starling gastrointestinal contents (n = 430) from 150 dairy farms in northeastern Ohio, USA. Isolates of E. coli O157:H7 recovered from these samples were subtyped using multilocus variable-number tandem repeat analysis (MLVA). Generated MLVA types were used to construct a dendrogram based on a categorical multistate coefficient and unweighted pair-group method with arithmetic mean (UPGMA). Using a focused spatial scan statistic, we identified statistically significant spatial clusters among dairy farms surrounding starling night roosts, with an increased prevalence of E. coli O157:H7-positive bovine faecal pats, increased diversity of distinguishable MLVA types and a greater number of isolates with MLVA types from bovine-starling clades versus bovine-only clades. Thus, our findings are compatible with the hypothesis that starlings have a role in the dissemination of E. coli O157:H7 among dairy farms, and further research into starling management is warranted. PMID:24279810

  3. Genomic characterization of pseudorabies virus strains isolated in Italy.

    PubMed

    Sozzi, E; Moreno, A; Lelli, D; Cinotti, S; Alborali, G L; Nigrelli, A; Luppi, A; Bresaola, M; Catella, A; Cordioli, P

    2014-08-01

    In this study, we undertook the genomic characterization of 54 pseudorabies virus (PRV) strains isolated in Italy during 1984-2010. The characterization was based on partial sequencing of the UL44 (gC) and US8 (gE) genes; 44 strains (38 for gene gE and 36 for gC) were isolated on pig farms; 9 originated from dogs and 1 from cattle. These porcine PRV strains, which were closely related to those isolated in Europe and America in the last 20 years, and the bovine strain bovine/It/2441/1992 belong to cluster B in both phylogenetic trees. Six porcine strains that do not belong to cluster B are related in both gE and gC phylogenetic trees to the 'old' porcine PRV strains isolated in the 1970s and 1980s. In the last two decades, the presence of these strains in domestic pig populations has been reduced drastically, whereas they are prevalent in wild boar. The two remaining strains have an interesting genomic profile, characterized by the gC gene being closely related to the old porcine PRV strains, and the gE gene being similar to that of recently isolated strains. Three strains originating from working dogs on pig farms are located in cluster B in both phylogenetic trees. Five strains isolated from hunting dogs have a high degree of correlation with PRV strains circulating in wild boar. The last isolate has a gC gene similar to that in the two porcine strains mentioned previously, and the gE gene is correlated with the strains isolated from hunting dogs. These results provide interesting insight into the genomic characterization of PRV strains and reveal a clear differentiation between the strains isolated from hunting dogs that are related to the wild boar strains and those originating from domestic pigs. PMID:23331342

  4. Prevalence of carriage of Shiga toxin-producing Escherichia coli serotypes O157:H7, O26:H11, O103:H2, O111:H8, and O145:H28 among slaughtered adult cattle in France.

    PubMed

    Bibbal, Delphine; Loukiadis, Estelle; Kérourédan, Monique; Ferré, Franck; Dilasser, Françoise; Peytavin de Garam, Carine; Cartier, Philippe; Oswald, Eric; Gay, Emilie; Auvray, Frédéric; Brugère, Hubert

    2015-02-01

    The main pathogenic enterohemorrhagic Escherichia coli (EHEC) strains are defined as Shiga toxin (Stx)-producing E. coli (STEC) belonging to one of the following serotypes: O157:H7, O26:H11, O103:H2, O111:H8, and O145:H28. Each of these five serotypes is known to be associated with a specific subtype of the intimin-encoding gene (eae). The objective of this study was to evaluate the prevalence of bovine carriers of these “top five” STEC in the four adult cattle categories slaughtered in France. Fecal samples were collected from 1,318 cattle, including 291 young dairy bulls, 296 young beef bulls, 337 dairy cows, and 394 beef cows. A total of 96 E. coli isolates, including 33 top five STEC and 63 atypical enteropathogenic E. coli (aEPEC) isolates, with the same genetic characteristics as the top five STEC strains except that they lacked an stx gene, were recovered from these samples.O157:H7 was the most frequently isolated STEC serotype. The prevalence of top five STEC (all serotypes included) was 4.5% in young dairy bulls, 2.4% in young beef bulls, 1.8% in dairy cows, and 1.0% in beef cows. It was significantly higher in young dairy bulls (P<0.05) than in the other 3 categories. The basis for these differences between categories remains to be elucidated. Moreover,simultaneous carriage of STEC O26:H11 and STEC O103:H2 was detected in one young dairy bull. Lastly, the prevalence of bovine carriers of the top five STEC, evaluated through a weighted arithmetic mean of the prevalence by categories, was estimated to 1.8% in slaughtered adult cattle in France. PMID:25527532

  5. Characteristics of the Shiga-toxin-producing enteroaggregative Escherichia coli O104:H4 German outbreak strain and of STEC strains isolated in Spain.

    PubMed

    Mora, Azucena; Herrrera, Alexandra; López, Cecilia; Dahbi, Ghizlane; Mamani, Rosalia; Pita, Julia M; Alonso, María P; Llovo, José; Bernárdez, María I; Blanco, Jesús E; Blanco, Miguel; Blanco, Jorge

    2011-09-01

    samples were also negative for other pathotypes of diarrheagenic E. coli (EAEC, ETEC, tEPEC, and EIEC). Consistent with data from other countries, STEC belonging to serotype O157:H7 and other serotypes have been isolated from beef, milk, cheese, and domestic (cattle, sheep, goats) and wild (deer, boar, fox) animals in Spain. Nevertheless, STEC outbreaks in Spain are rare. PMID:22101411

  6. PCR and ELISA (VIDAS ECO O157®) Escherichia coli O157:H7 identification in Minas Frescal cheese commercialized in Goiânia, GO

    PubMed Central

    Carvalho, Rosangela Nunes; de Oliveira, Antonio Nonato; de Mesquita, Albenones José; Minafra e Rezende, Cíntia Silva; de Mesquita, Adriano Queiroz; Romero, Rolando Alfredo Mazzoni

    2014-01-01

    Escherichia coli O157:H7 has been incriminated in food poisoning outbreaks and sporadic cases of hemorrhagic colitis and hemolytic uremic syndrome in many countries. Considering the high susceptibility of Minas Frescal cheese to contamination by E. coli O157:H7, the aim of this study was to determine the occurrence of this pathogen through PCR (Polymerase Chain Reaction) and ELISA (VIDAS ECO O157®, bioMérieux, Lyon, France) test. Thirty cheese samples manufactured by artisan farmhouse producers were collected from open-air markets in Goiânia and thirty from industries under Federal Inspection located in Goiás State which trade their products in supermarkets in Goiânia. E. coli O157:H7 was detected in 6.67% samples collected in open air markets using ELISA, and 23,33% with PCR. The pathogen was not detected in samples from industries under Federal Inspection. PMID:24948907

  7. PCR and ELISA (VIDAS ECO O157(®)) Escherichia coli O157:H7 identification in Minas Frescal cheese commercialized in Goiânia, GO.

    PubMed

    Carvalho, Rosangela Nunes; de Oliveira, Antonio Nonato; de Mesquita, Albenones José; Minafra e Rezende, Cíntia Silva; de Mesquita, Adriano Queiroz; Romero, Rolando Alfredo Mazzoni

    2014-01-01

    Escherichia coli O157:H7 has been incriminated in food poisoning outbreaks and sporadic cases of hemorrhagic colitis and hemolytic uremic syndrome in many countries. Considering the high susceptibility of Minas Frescal cheese to contamination by E. coli O157:H7, the aim of this study was to determine the occurrence of this pathogen through PCR (Polymerase Chain Reaction) and ELISA (VIDAS ECO O157(®), bioMérieux, Lyon, France) test. Thirty cheese samples manufactured by artisan farmhouse producers were collected from open-air markets in Goiânia and thirty from industries under Federal Inspection located in Goiás State which trade their products in supermarkets in Goiânia. E. coli O157:H7 was detected in 6.67% samples collected in open air markets using ELISA, and 23,33% with PCR. The pathogen was not detected in samples from industries under Federal Inspection. PMID:24948907

  8. Serotypes, virulence genes and intimin types of Shiga toxin (verocytotoxin)-producing Escherichia coli isolates from minced beef in Lugo (Spain) from 1995 through 2003

    PubMed Central

    Mora, Azucena; Blanco, Miguel; Blanco, Jesús E; Dahbi, Ghizlane; López, Cecilia; Justel, Paula; Alonso, María Pilar; Echeita, Aurora; Bernárdez, María Isabel; González, Enrique A; Blanco, Jorge

    2007-01-01

    Background Shiga toxin-producing Escherichia coli (STEC) have emerged as pathogens that can cause food-borne infections and severe and potentially fatal illnesses in humans, such as haemorrhagic colitis (HC) and haemolytic uraemic syndrome (HUS). In Spain, like in many other countries, STEC strains have been frequently isolated from ruminants, and represent a significant cause of sporadic cases of human infection. In view of the lack of data on STEC isolated from food in Spain, the objectives of this study were to determine the level of microbiological contamination and the prevalence of STEC O157:H7 and non-O157 in a large sampling of minced beef collected from 30 local stores in Lugo city between 1995 and 2003. Also to establish if those STEC isolated from food possessed the same virulence profiles as STEC strains causing human infections. Results STEC were detected in 95 (12%) of the 785 minced beef samples tested. STEC O157:H7 was isolated from eight (1.0%) samples and non-O157 STEC from 90 (11%) samples. Ninety-six STEC isolates were further characterized by PCR and serotyping. PCR showed that 28 (29%) isolates carried stx1 genes, 49 (51%) possessed stx2 genes, and 19 (20%) both stx1 and stx2. Enterohemolysin (ehxA) and intimin (eae) virulence genes were detected in 43 (45%) and in 25 (26%) of the isolates, respectively. Typing of the eae variants detected four types: γ1 (nine isolates), β1 (eight isolates), ε1 (three isolates), and θ (two isolates). The majority (68%) of STEC isolates belonged to serotypes previously detected in human STEC and 38% to serotypes associated with STEC isolated from patients with HUS. Ten new serotypes not previously described in raw beef products were also detected. The highly virulent seropathotypes O26:H11 stx1 eae-β1, O157:H7 stx1stx2 eae-γ1 and O157:H7 stx2eae-γ1, which are the most frequently observed among STEC causing human infections in Spain, were detected in 10 of the 96 STEC isolates. Furthermore, phage typing

  9. Global transcriptional response of Escherichia coli O157:H7 to growth transitions in glucose minimal medium

    PubMed Central

    Bergholz, Teresa M; Wick, Lukas M; Qi, Weihong; Riordan, James T; Ouellette, Lindsey M; Whittam, Thomas S

    2007-01-01

    Background: Global patterns of gene expression of Escherichia coli K-12 during growth transitions have been deeply investigated, however, comparable studies of E. coli O157:H7 have not been explored, particularly with respect to factors regulating virulence genes and genomic islands specific to this pathogen. To examine the impact of growth phase on the dynamics of the transcriptome, O157:H7 Sakai strain was cultured in MOPS minimal media (0.1% glucose), RNA harvested at 10 time points from early exponential to full stationary phase, and relative gene expression was measured by co-hybridization on high-density DNA microarrays. Expression levels of 14 genes, including those encoding Shiga toxins and other virulence factors associated with the locus of enterocyte effacement (LEE), were confirmed by Q-PCR. Results: Analysis of variance (R/MAANOVA, Fs test) identified 442 (36%) of 1239 O157-specific ORFs and 2110 (59%) of 3647 backbone ORFs that changed in expression significantly over time. QT cluster analysis placed 2468 of the 2552 significant ORFs into 12 groups; each group representing a distinct expression pattern. ORFs from the largest cluster (n = 1078) decreased in expression from late exponential to early stationary phase: most of these ORFs are involved in functions associated with steady state growth. Also represented in this cluster are ORFs of the TAI island, encoding tellurite resistance and urease activity, which decreased ~4-fold. Most ORFs of the LEE pathogenicity island also decreased ~2-fold by early stationary phase. The ORFs encoding proteins secreted via the LEE encoded type III secretion system, such as tccP and espJ, also decreased in expression from exponential to stationary phase. Three of the clusters (n = 154) comprised genes that are transiently upregulated at the transition into stationary phase and included genes involved in nutrient scavenging. Upregulated genes with an increase in mRNA levels from late exponential to early stationary

  10. Antibacterial activity of bee honey and its therapeutic usefulness against Escherichia coli O157:H7 and Salmonella typhimurium infection.

    PubMed

    Badawy, O F H; Shafii, S S A; Tharwat, E E; Kamal, A M

    2004-12-01

    The authors studied the effect of storage period and heat on the physical and chemical properties of honey and proceeded to study the antibacterial effect of honey on Escherichia coli and Salmonella typhimurium. In samples of honey (Egyptian clover honey) that were heat-treated and stored over a long period of time, water content decreased, hydroxymethyl furfural (HMF) was produced and increased in concentration, and enzyme activity decreased. Colour, measured in optical density, was markedly affected in honey samples stored over long periods of time, as was the refractive index, but electrical conductivity remained unaffected by storage or heating. Similarly, the storage period had no effect on pH value. To study the therapeutic effect of honey on E.coli and S. typhimurium, 25 isolates of E. coil O157:H7 (18.5%) and 49 isolates of S. typhimurium (36.2%) were isolated from 135 samples taken from children and calves (30 stool samples from children and 105 samples from calf organs and faecal swabs). Most E. coli O157:H7 and S. typhimurium isolates were highly resistant to most antibiotic discs. In vitro, the antibacterial effect of honey was more pronounced on E. coil O157:H7 than on S. typhimurium. Water content, pH value, HMF and the presence of H2O, all played an important role in the potency of olover honey as an antibacterial agent. In vivo, mice were used as a model for studying the parenteral usefulness of honey as an antibacterial agent against both pathogens. The antibacterial activity of honey that had been stored over a long period of time decreased and high concentrations of honey proved more effective as antibacterial agents. In this study there was lower mortality among mice treated with honey but the parenteral application of honey and its therapeutic properties require further investigation. PMID:15861897

  11. Evaluation of BBL CHROMagar O157 versus Sorbitol-MacConkey Medium for Routine Detection of Escherichia coli O157 in a Centralized Regional Clinical Microbiology Laboratory▿

    PubMed Central

    Church, D. L.; Emshey, D.; Semeniuk, H.; Lloyd, T.; Pitout, J. D.

    2007-01-01

    The performance of BBL CHROMagar O157 (CHROM) versus that of sorbitol-MacConkey (SMAC) media for detection of Escherichia coli O157 was determined for a 3-month period. Results for 27/3,116 (0.9%) stool cultures were positive. CHROM had a higher sensitivity (96.30%) and negative predictive value (100%) and a better diagnostic efficiency than SMAC. Labor and material costs decreased when CHROM was used. PMID:17634298

  12. The intranasal vaccination of pregnant dams with Intimin and EspB confers protection in neonatal mice from Escherichia coli (EHEC) O157:H7 infection.

    PubMed

    Rabinovitz, B C; Larzábal, M; Vilte, D A; Cataldi, A; Mercado, E C

    2016-05-27

    Enterohemorrhagic Escherichia coli (EHEC) O157:H7 is responsible for intestinal disease and hemolytic uremic syndrome (HUS), a serious systemic complication which particularly affects children. In this study, we evaluated whether passive immunization protects from EHEC O157:H7 colonization and renal damage, by using a weaned BALB/c mouse model of infection. Recombinant proteins EspB and the carboxyl-terminal fragment of 280 amino acids of γ-intimin (γ-IntC280) were used in combination with a macrophage-activating lipopeptide-2 (MALP) adjuvant to immunize pregnant mice by the intranasal route. Neonatal mice were allowed to suckle vaccinated or sham-vaccinated dams until weaning when they were challenged by the oral route with a suspension of an E. coli O157:H7 Stx2+ strain. The excretion of the inoculated strain was followed for 72h. All vaccinated dams exhibited elevated serum IgG response against both γ-Int C280 and EspB. Passive immunization of newborn mice resulted in a significant increase in serum IgG titers against γ-Int C280 and a slight increase in EspB-specific antibodies. The neonates from vaccinated dams showed a significant reduction in EHEC O157:H7 colonization 48h post challenge. In addition, the level of plasma urea concentration, a marker of renal failure, was significantly higher in offsprings of sham-vaccinated mice. In conclusion, vaccination of pregnant dams with γ-Int C280 and EspB could reduce colonization and systemic toxicity of EHEC O157:H7 in their suckling offsprings. PMID:27129423

  13. Correlating levels of type III secretion and secreted proteins with fecal shedding of Escherichia coli O157:H7 in cattle.

    PubMed

    Sharma, V K; Sacco, R E; Kunkle, R A; Bearson, S M D; Palmquist, D E

    2012-04-01

    The locus of enterocyte effacement (LEE) of Escherichia coli O157:H7 (O157) encodes a type III secretion system (T3SS) for secreting LEE-encoded and non-LEE-encoded virulence proteins that promote the adherence of O157 to intestinal epithelial cells and the persistence of this food-borne human pathogen in bovine intestines. In this study, we compared hha sepB and hha mutants of O157 for LEE transcription, T3SS activity, adheren