Escherichia coli Shigatoxigênicas sorogrupos O157, O111 e O113 detectadas em fezes de bovinos, água e leite de propriedades leiteiras

bjm Brazilian Journal of Microbiology Braz. J. Microbiol. 1517-8382 1678-4405 Sociedade Brasileira de Microbiologia São Paulo, SP, Brazil Este trabalho teve como objetivo determinar a prevalência de Escherichia coli Shigatoxigênicas dos sorogrupos O157, O111 e O113 em bovinos leiteiros, água e leite de propriedades rurais do Município de Jaboticabal/SP. Para isso, foram colhidas 454 amostras de fezes, 54 amostras de água e 30 amostras de leite e pesquisada a presença de seqüências stx1, stx2 e eae pela reação em cadeia da polimerase (PCR). Todas as amostras stx e/ eae positivas foram submetidas a uma nova reação de PCR para detecção das seqüências rfb O157, rfb O111 e rfb O113. Uma alta ocorrência (59,9%) de stx foi detectada nas fezes dos bovinos. Os coeficientes de prevalência das seqüências rfb O157, O111 e O113 nas fezes dos bovinos foram, respectivamente, 18,9%, 3,3% e 30,4%. Todas as seqüências foram encontradas com maior freqüência em bezerros e novilhas. As seqüências eae e stx2 foram as mais detectadas entre as amostras de fezes. Foram detectados 1,9% e 3,3% de seqüências stx na água e no leite, respectivamente. Nas amostras de água observou-se uma baixa prevalência de O113 e não foram detectadas O157 e O111. Nenhum dos sorogrupos pesquisados foi encontrado nas amostras de leite. STEC foram identificadas em todos os rebanhos (100%) e os sorogrupos O157, O111 e O113 foram observados em 40,0%, 50,0% e 90,0% dos rebanhos. Conclui-se que a prevalência de STEC em fezes de bovino, no Município de Jaboticabal/SP é alta, caracterizando-a como importante via de contaminação ambiental para esses microrganismos. VETERINARIAN MICROBIOLOGY Shigatoxigenic Escherichia coli serogroups O157, O111 and O113 in feces, water and milk samples from dairy farms Escherichia coli Shigatoxigênicas sorogrupos O157, O111 e O113 detectadas em fezes de bovinos, água e leite de propriedades leiteiras Hinig Isa Godoy VicenteI,*; Luiz Augusto do AmaralI; Aloysio de Mello Figueiredo CerqueiraII IDepartamento de Medicina Veterinária Preventiva, Universidade Estadual Paulista, Jaboticabal, SP, Brasil IIDepartamento de Microbiologia e Parasitologia, Instituto Biomédico, Universidade Federal Fluminense Niterói, RJ, Brasil ABSTRACT The objective of this study was to determine the prevalence of Shigatoxigenic Escherichia coli (STEC) and STEC serogroups O157, O111 and O113 in feces, water and milk sampled in dairy farms in Jaboticabal, SP, Brazil. Feces (n=454), water (n=54) and milk samples (n=30) were collected from 10 herds and assessed for the presence of the virulence genes stx1, stx2 and eae by polymerase chain reaction (PCR). All stx and eae positive samples were submitted to a second PCR reaction targeting the sequences rfb O157, rfb O111 and rfb O113. High prevalence of stx was detected (59.9%) in fecal samples, whereas the prevalence of sequences rfb O157, rfb O111 and rfb O113 was 18.9%, 3.3% and 30.4%, respectively. All sequences were detected more frequently in calves and heifers. Sequences stx2 and eae were prevalent in the fecal samples. stx sequences were detected in 1.9% and 3.3% of water and milk samples, respectively. Low prevalence of E. coli O113 was observed in water samples, whereas no E. coli O157 or E. coli O111 was detected. Furthermore, none of the serogroups were identified in milk samples. STEC was identified in all herds (100%), and serogroups O157, O111 and O113 were observed in 40%, 50% and 90% of the herds, respectively. In conclusion, the high STEC prevalence detected in dairy herds evidences that bovine feces might play an important role as a contamination source in the region of Jaboticabal, Brazil. Key words: Shigatoxigenic, Escherichia coli, milk, water, bovine feces RESUMO Este trabalho teve como objetivo determinar a prevalência de Escherichia coli Shigatoxigênicas dos sorogrupos O157, O111 e O113 em bovinos leiteiros, água e leite de propriedades rurais do Município de Jaboticabal/SP. Para isso, foram colhidas 454 amostras de fezes, 54 amostras de água e 30 amostras de leite e pesquisada a presença de seqüências stx1, stx2e eae pela reação em cadeia da polimerase (PCR). Todas as amostras stx e/ eae positivas foram submetidas a uma nova reação de PCR para detecção das seqüências rfb O157, rfb O111 e rfb O113. Uma alta ocorrência (59,9%) de stx foi detectada nas fezes dos bovinos. Os coeficientes de prevalência das seqüências rfb O157, O111 e O113 nas fezes dos bovinos foram, respectivamente, 18,9%, 3,3% e 30,4%. Todas as seqüências foram encontradas com maior freqüência em bezerros e novilhas. As seqüências eae e stx2 foram as mais detectadas entre as amostras de fezes. Foram detectados 1,9% e 3,3% de seqüências stx na água e no leite, respectivamente. Nas amostras de água observou-se uma baixa prevalência de O113 e não foram detectadas O157 e O111. Nenhum dos sorogrupos pesquisados foi encontrado nas amostras de leite. STEC foram identificadas em todos os rebanhos (100%) e os sorogrupos O157, O111 e O113 foram observados em 40,0%, 50,0% e 90,0% dos rebanhos. Conclui-se que a prevalência de STEC em fezes de bovino, no Município de Jaboticabal/SP é alta, caracterizando-a como importante via de contaminação ambiental para esses microrganismos. Palavras-chave: Shigatoxigênica, Escherichia coli, leite, água, fezes de bovinos INTRODUCTION Enterohaemorrhagic Escherichia coli (EHEC) are human pathogens that belong to the Shigatoxigenic E. coli (STEC) group. They may cause several diseases, ranging from hemorrhagic colitis to more serious syndromes that may result in death of children and the elderly, such as hemolytic uremic syndrome and thrombotic thrombocytopenic purpura (28,31,47). STEC transmission is often related to the consumption of contaminated food, uncooked beef, water and raw milk (19). The morbidity and mortality rates associated with many outbreaks of gastrointestinal diseases caused by Shigatoxigenic Escherichia coli have highlighted the threat that these organisms pose to public health (35). STEC pathogenicity is mainly attributed to the expression of genes related to the production of cytotoxins (stx1 and stx2) and adherence factors (eae) (1). Although more than 200 E. coli serotypes produce shigatoxins, only a limited but increasing number is considered pathogenic to humans. Serotype O157:H7 is still the predominant serotype among enterohaemorragic Escherichia coli, and the serotype most frequently associated with foodborne outbreaks (47). Dairy cattle have been regarded as the primary host of STEC (3,20,25,42,48). Additionally, calves and heifers have been considered the age group most susceptible to serotype O157:H7 and other STEC (19,20,48). Although isolation have been reported in calves with diarrhea (3,33), these microorganisms are frequently recovered from healthy animals (32,48). Since infected animals usually show no clinical signs, the control of disease transmission cannot be easily achieved (16). STEC strains that are pathogenic to humans have been shown to belong to a broad range of O serogroups. Nevertheless, it seems that especially enterohaemorragic Escherichia coli O157 and O111, and more recently also O113, are responsible for the majority of severe cases (27,38). The present study was carried out to provide additional information about the prevalence and epidemiology of Shigatoxigenic E. coli (STEC) in dairy farms. MATERIALS AND METHODS A simple random sample was selected by drawing ten dairy herds in the region of Jaboticabal, State of São Paulo, Brazil. Fecal samples from all animals (454), water samples (54) and milk samples (30) were collected between January and March 2002. The prevalence of STEC was evaluated in the 538 samples by polymerase chain reaction (PCR). Afterwards, the prevalence of serogroups O157, O111 and O113 was analyzed by PCR in the STEC-positive samples. The results of fecal samples were analyzed considering three age groups: calves (< 4 months); heifers (from 5 months to 2 years); and cows (> 2 years). Sampling Water samples Samples were collected in six different locations within each dairy farm: water source (shallow well, spring or deep well), drinking water consumed by workers, water used in the dairy stable, drinkers for cows, drinkers for heifers and drinkers for calves. Fecal samples Rectal swabs were collected from every animal with or without diarrhea, and transported in Cary-Blair transport medium (Copan, Italy). Milk samples Samples were collected directly from the refrigerated milk tank through the faucet. Sampling was performed at the beginning, in the middle and at the end of the milking process. Samples were taken to the laboratory under refrigeration and processed immediately. Polymerase Chain Reaction (PCR) Sample preparation Feces: Samples were streaked onto cystine lactose electrolyte deficient agar (CLED - Difco, France) and incubated at 37ºC for 18-24h to form a bacterial lawn (confluent growth). Polymicrobial growth was collected in approximately 2 mL of phosphate buffered saline (PBS; pH 7.4) and 100 µL were diluted using sterile distilled water (1:10). Total DNA was extracted from the diluted bacterial suspension by boiling for 10 min. Bacterial glycerol stocks were prepared using two aliquots of the bacterial suspension (0.5 mL) diluted with 0.5 mL of 2X tryptic soy broth (TSB - Oxoid, Basingstone) containing 20% glycerol and stored at -70ºC (10). Water:Sources, human consumption and dairy stable —100-mL aliquots of the samples were filtered through a sterile membrane (0.45 µm, Millipore) and poured into flasks containing 50 mL TSB. After incubation at 37ºC for 18-24h, the samples were streaked onto cystine lactose electrolyte deficient agar. Further procedures were similar to those used with fecal samples. Animal drinkers - Thirty milliliters of each water sample were transferred to a sterilized flask containing 30 mL of 2X TSB, homogenized and incubated overnight at 37ºC (22). Samples were streaked onto cystine lactose electrolyte deficient agar and further procedures were similar to those described for fecal samples. Milk: Samples (30 mL) were transferred to a sterile flask containing 30 mL of 2X TSB, homogenized and incubated overnight at 37ºC. Aliquots (1 mL) were taken and centrifuged (12). The supernatant was discarded and the pellet was streaked onto cystine lactose electrolyte deficient agar. Further steps were as described above for fecal samples. Multiplex PCR for stx1, stx2 and eae The detection of stx1, stx2 and eae was performed by a multiplex PCR previously described (11). The following primer sets were used to detect eae, stx1 and stx2 sequences of shigatoxigenic E. coli: ep1 and ep2, stx1R and stx1F, stx2R and stx2F (BioSynthesis, United States): ep1 - 5' AGG CTT CGT CAC AGT TG 3' ep2 - 5' CCA TCG TCA CCA GAG GA 3' stx1R - 5' AGA GCG ATG TTA CGG TTTG 3' stx1F - 5' TTG CCC CCA GAG TGG ATG 3' stx2R - 5' TGG GTT TTT CTT CGG TATC 3' stx2F - 5' GAC ATT CTG GTT GAC TCT CTT 3' The PCR mixture (20µL) was prepared using 2.0 µL of 10X PCR buffer (Gibco BRL), 0.6 µL of 1.5 mM MgCl2 (Gibco BRL), 0.4 µL of 2 mM dNTP (Gibco BRL), 0.1 µL (250 mM) of each primer, 0.2 µL of Taq DNA polymerase - (1U Gibco BRL), 11.2 µL of sterile water and 5 µL of template DNA. Amplifications were carried out in a thermal cycler (MJ Reserch, Inc) according to the following conditions: initial denaturation at 94ºC for 5', 30 cycles at 94ºC for 30'', 52ºC for 30'', 72ºC for 1'30''. Controls were included in every batch of samples. A negative control without DNA was used, as well as control reactions including DNA extracted from Stx-negative E. coli DH5a (K12), Stx-positive STEC strain E40705 stx1 and eae (CPHL, London) and Stx-positive STEC strain E30138 stx2 and eae. Amplified products were visualized by electrophoresis in 1.0% agarose gel stained with ethidium bromide. Multiplex PCR for rfb O157, O113 and O111 All stx- and eae-positive samples were submitted to a second multiplex PCR according to the procedure described by Paton and Paton (36), using the primers described below (BioSynthesis, United States): O157 F - 5' CGG ACA TCC ATG TGA TAT GG 3' O157 R - 5' TTG CCT ATG TAC AGC TAA TCC 3' O113 F - 5' AGC GTT TCT GAC ATA TGG AGTG 3' O113 R - 5' GTG TTA GTA TCA AAA GAG GCT CC 3' O111 F - 5' TAG AGA AAT TAT CAA GTT AGT TCC 3' O111 R. - 5' ATA GTT ATG AAC ATC TTG TTT AGC 3' PCR mixtures (20µL) were prepared using 2.0 µL of 10X PCR buffer (Gibco BRL), 0.6 µL of 1.5 mM MgCl2 (Gibco BRL), 0.4 µL of 2 mM dNTP, 0.1 µL (250 mM) of each primer, 0.2 µL of Taq DNA polymerase (1U), 11 µL of sterile water and 5 µL of template DNA. Amplification was carried out using a thermal cycler (MJ Research, Inc) under the following conditions: 10 cycles at 95ºC for 1', 65ºC for 2', 72ºC for 1'30'', 15 cycles at 95ºC for 1', 60ºC for 2', 72ºC for 1'30'', 10 cycles at 95ºC for 1', 60ºC for 2', 72ºC for 2'30''. Control reactions were included in every batch of samples: negative control without DNA, Stx-negative E. coli DH5a (K12), Stx-positive STEC strains E40705 or E30138 (O157), E. coli O113:H21 (O113) and EPEC strain B171 (O111). Amplified products were visualized by electrophoresis in 1.0% agarose gel stained with ethidium bromide. RESULTS AND DISCUSSION There was a high prevalence (59.9%) of stx sequences in feces from dairy cattle (Table 1). STEC prevalence data of previous studies in dairy farms are highly variable. In the USA, Wells et al. (48) reported that STEC was detected in 19% of feces from calves and 8% of feces from adult cows. In Canada, a herd prevalence of 45% was reported in 1992 (26). In Argentina, Sanz et al. (43) found a prevalence of 44% in cows. Busato et al. (7), in Switzerland, detected STEC in 44.3% of the animals and Cerqueira et al. (10) found prevalence as high as 82% in some herds of the State of Rio de Janeiro, Brazil The prevalence of serogroup O157 was 18.9% in feces (Table 1). This value is higher than the findings presented by Hancock et al. (21) and Vold et al. (47), who reported prevalence of 1.0%. The frequencies of stx (59.9%) and rfb O157 (18.9%) detected in the present study were relatively high. Nevertheless, data on prevalence of STEC and E. coli O157 in cattle are difficult to be compared due to differences in the procedures and detection methods that are used. Only 3.3% of animals were shown to carry rfb O111-positive E. coli (Table 1). Although this prevalence is relatively low, it should be pointed out that serogroup O111 has been involved in most non-O157 STEC infections (2). Besides, STEC O111 has been reported as responsible for outbreaks (6,8,9,23,37) and also sporadic cases (15,18,19,46). STEC strains carrying the eae gene are considered more virulent for humans than strains lacking eae (1). However, it has been reported that eae-negative E. coli O113 strains are capable of colonizing the human gastrointestinal tract and cause hemolyticuremic syndrome (38). It should be noted that high prevalence (30.4%) of E. coli carrying O113 rfb sequences was seen in the present study (Fig. 1). Therefore, measures must be taken in order to reduce the risk of environmental contamination and transmission to humans. It is known that water is an important means of spreading STEC between animals and humans. From 54 analyzed water samples, 1.9% presented stx and 1.9% presented the sequence rfb O113, but in no samples rfb O157 or O111 sequences were detected (Table 1). Although STEC prevalence in water samples was low, the importance of water as a vehicle of disease transmission cannot be disregarded. Many outbreaks of gastrointestinal diseases have been reported and evidences indicate the importance of water in STEC epidemiology (14,17,25,30,45). Moreover, the etiological agent is not recovered in most gastrointestinal disease outbreaks involving water (41). Therefore, any required and possible measures should be taken in order to prevent water contamination. Dairy cattle are considered natural hosts of STEC O157 strains that are pathogenic for humans (24). Milk and meat products, which are both produced by dairy herds, are responsible for the majority of the foodborne outbreaks caused by these microorganisms (44). Therefore, although rfb O157, O111 or O113 sequences have not been detected in milk samples in the present study, the detection of E. coli carrying stx sequences in 3.3% of milk samples may pose a risk to public health (Table 1). Higher prevalence of stx, rfb O157 and rfb O111 was observed in calves and heifers compared to cows (Table 2). These results are in agreement with findings described by Wells et al. (48), Wilson et al. (50), Zhao et al. (51), Rahn et al. (40) and Busato et al. (7). The reasons for such difference in prevalence between age groups are still unknown, but the variations might reflect differences in ruminal development, diet and resistance to infections, among other factors (48). Notwithstanding, it is also necessary to control STEC infection in older animals, since most ground beef and dairy products are derived from adult animals (13). In the present study, the prevalence of eae and stx2sequences was higher in fecal samples, 45.8% and 31.5%, respectively (Fig. 1). These findings agree with data reported by Blanco et al. (5), Miyao et al. (31), Sanz et al. (43), Vold et al. (47) and Cerqueira et al. (10). The importance of these data lies on the fact that eae-positive STEC strains are considered more virulent for humans than eae-negative STEC strains, as well as strains carrying only stx2genes (1,34,49). According to Blanco et al. (4), Stx2-producing strains of STEC are part of the normal intestinal flora in cattle, which is probably the reason why stx2 sequence was detected more frequently. Moreover, stx1 and stx2 sequences are located on mobile genetic elements and might have different mobility patterns. Therefore, the transference of stx2 from non-pathogenic to pathogenic serotypes may happen more frequently (47). The percentage of dairy farms in which stx and rfb O113 sequences of E. coli were detected in fecal samples was very high, 100% and 90%, respectively. The sequences rfb O157 and O111 were also observed in reasonably high percentages, 40% and 50% (Fig. 2). These results give evidences that the four groups of bacteria are widely spread among animals in dairy farms in Jaboticabal, SP. Efforts should be focused on infection control in order to reduce the prevalence of such microorganisms (40). According to Kudva et al. (28), Escherichia coli O157 may survive at least six weeks in feces and possibly multiply in this material. Serotype O157:H7 was isolated more frequently from environmental samples collected next to manure deposits (39). Furthermore, higher STEC and O157 prevalence may be seen in herds that graze in paddocks treated with manure (20,29). Therefore, adequate manure management is one of the methods that prevent bovine feces from becoming a source of environmental contamination with shigatoxigenic Escherichia coli. Besides appropriate manure management, there are other measures to be taken in order to prevent the spread of STEC. These include stress prevention, controlling food and water quality, as well as feedlot conditions and contact between adult and young animals (40). In conclusion, this study showed high prevalence of Shigatoxigenic E. coli in dairy cattle, especially in calves and heifers. Besides, STEC is widely spread in dairy farms in Jaboticabal, SP, Brazil. It is suggested that dairy cattle are important reservoirs of E. coli serogroups O157, O111, O113 and other STEC, and are an important source of environmental contamination, through microorganism shedding in the feces. ACKNOWLEDGEMENTS This study was supported by grants from Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP, grant nº. 01/09922-0). Submitted: December 02, 2004; Returned to authors for corrections: May 27, 2005; Approved: September 12, 2005 * Corresponding Author. Mailing address: Departamento de Medicina Veterinária Preventiva, Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista. Via de Acesso Prof. Paulo D. Castellane, Km 5. 14884-900, Jaboticabal, SP, Brasil. Tel.: [phone]. E-mail: [e-mail] 1. Barret, T.J.; Kaper, J.B.; Jerse, A.E.; Wachsmuth, I.K. Virulence factors in Shiga-like toxin-producing Escherichia coli isolated from humans and cattle. J. Infect. Dis., 165, 979-980, 1992. Virulence factors in Shiga-like toxin-producing Escherichia coli isolated from humans and cattle J. Infect. Dis. 1992 979 980 165 Barret T.J. Kaper J.B. Jerse A.E. Wachsmuth I.K. 2. Bettelheim. K. A. Role of non-O157 VTEC. J. Appl. Microbiol. Suppl., 88, 38-50, 2000. Role of non-O157 VTEC J. Appl. Microbiol. Suppl. 2000 38 50 88 Bettelheim K. A. 3. Blanco, J.; Gonzalez, E.A.; Garcia, S.; Blanco, M.; Regueiro, B.; Bernardez, I. Production of toxins by Escherichia coli strains isolated from calves with diarrhoea in Galia (North-western Spain). Vet. Microbiol., 18, 297-311, 1988. Production of toxins by Escherichia coli strains isolated from calves with diarrhoea in Galia (North-western Spain) Vet. Microbiol. 1988 297 311 18 Blanco J. Gonzalez E.A. Garcia S. Blanco M. Regueiro B. Bernardez I. 4. Blanco, M.; Blanco, J.; Blanco, J.E.; Ramos, J. Enterotoxigenic, verotoxigenic, and necrotoxigenic Escherichia coli isolated from cattle in Spain. Am. J. Vet. Res., 54, 1446-1451, 1993. Enterotoxigenic, verotoxigenic, and necrotoxigenic Escherichia coli isolated from cattle in Spain Am. J. Vet. Res. 1993 1446 1451 54 Blanco M. Blanco J. Blanco J.E. Ramos J. 5. Blanco, M.; Blanco, J.E.; Blanco, J.; Mora, A.; Prado, C.; Alonso, M.C.; Mourino, M.; Madrid, C.; Balsalobre, C.; Juarez, A. Distribution and characterization of fecal verotoxin producing Escherichia coli (VTEC) isolated from healthy cattle. Vet. Microbiol., 54, 309-319, 1997. Distribution and characterization of fecal verotoxin producing Escherichia coli (VTEC) isolated from healthy cattle Vet. Microbiol. 1997 309 319 54 Blanco M. Blanco J.E. Blanco J. Mora A. Prado C. Alonso M.C. Mourino M. Madrid C. Balsalobre C. Juarez A. 6. Boudaillez, B.; Berquin, P.; Mariani-Kurkdjian, P. Possible person-to-person transmission of Escherichia coli O111 - associated hemolytic uremic syndrome. Pediatr. Nephrl., 11, 36-39, 1996. Possible person-to-person transmission of Escherichia coli O111 - associated hemolytic uremic syndrome Pediatr. Nephrl. 1996 36 39 11 Boudaillez B. Berquin P. Mariani-Kurkdjian P. 7. Busato, A.; Hofer, D.; Lentze, T.; Gaillard, C.; Burnens, A. Prevalence and infection risks of zoonotic enteropathogenic bacterium in Swiss cow-calf farms. Vet. Microbiol., 69, 251-263, 1999. Prevalence and infection risks of zoonotic enteropathogenic bacterium in Swiss cow-calf farms Vet. Microbiol. 1999 251 263 69 Busato A. Hofer D. Lentze T. Gaillard C. Burnens A. 8. Caprioli, A.; Tozzi, E. Epidemiology of Shiga toxin-producing Escherichia coli infections in continental Europe. In: Kaper, J.B.; O'brien, A.D. (ed.). Escherichia coli O157:H7 and other Shiga toxin-producing E. coli strains. Am. Soc. Microbiol., Washington, D.C., 1998, p. 38-48. Escherichia coli O157:H7 and other Shiga toxin-producing E. coli strains 1998 38 48 Caprioli A. Tozzi E. Kaper J.B. O'brien A.D. 9. Caprioli, A.; Luzzi, I.; Rosmini, F. Communitywide outbreak of hemolytic-uremic syndrome associated with non-O157 verotoxin-producing Escherichia coli. J. Infect. Dis., 169, 208-211, 1994. Communitywide outbreak of hemolytic-uremic syndrome associated with non-O157 verotoxin-producing Escherichia coli J. Infect. Dis. 1994 208 211 169 Caprioli A. Luzzi I. Rosmini F. 10. Cerqueira, A.M.F.; Guth, B.E.C.; Joaquim, R.M.; Andrade, J.R.C. High occurrence of Shiga toxin-producing Escherichia coli (STEC) in healthy cattle in Rio de Janeiro State, Brazil. Vet. Microbiol., 70, 111-121, 1999. High occurrence of Shiga toxin-producing Escherichia coli (STEC) in healthy cattle in Rio de Janeiro State, Brazil Vet. Microbiol. 1999 111 121 70 Cerqueira A.M.F. Guth B.E.C. Joaquim R.M. Andrade J.R.C. 11. China, B.; Pirson, V.; Mainil, J. Typing of Bovine Attaching and Effacing Escherichia coli by Multiplex In Vitro Amplification of Virulence-Associated Genes. Appl. Environ. Microbiol., 62(9), 3462-3465, 1996. Typing of Bovine Attaching and Effacing Escherichia coli by Multiplex In Vitro Amplification of Virulence-Associated Genes Appl. Environ. Microbiol. 1996 3462 3465 9 62 China B. Pirson V. Mainil J. 12. Cobbold, R.; Desmarchelier, P. The longitudinal study of Shigatoxigenic Escherichia coli (STEC) prevalence in three Australian dairy herds. Vet. Microbiol., 71, 125-137, 2000. The longitudinal study of Shigatoxigenic Escherichia coli (STEC) prevalence in three Australian dairy herds Vet. Microbiol. 2000 125 137 71 Cobbold R. Desmarchelier P. 13. Cray Jr., W.C.; Moon, H.W. Experimental Infection of Calves and Adults Cattle with Escherichia coli O157:H7. Appl. Environ. Microbiol., 61(4), 586-1590, 1995. Experimental Infection of Calves and Adults Cattle with Escherichia coli O157:H7 Appl. Environ. Microbiol. 1995 586 1590 4 61 Cray Jr. W.C. Moon H.W. 14. Dev, V.J.; Main, M.; Gould, I. Waterborne outbreak of Escherichia coli O157 (Letter). Lancet, 1, 1412, 1991. Waterborne outbreak of Escherichia coli O157 (Letter) Lancet 1991 1 Dev V.J. Main M. Gould I. 15. Eklund, M.; Scheutz, F.; Siitonen, A. Clinical isolates the non-O157 shiga toxin-producing Escherichia coli: serotypes, virulence characteristics, and molecular profiles of strains of the same serotype. J. Clin. Microbiol., 39(8), 2829-2834, 2001. Clinical isolates the non-O157 shiga toxin-producing Escherichia coli: serotypes, virulence characteristics, and molecular profiles of strains of the same serotype J. Clin. Microbiol. 2001 2829 2834 8 39 Eklund M. Scheutz F. Siitonen A. 16. Garber, L.P.; Wells, S.J.; Hancock, D.D.; Doyle, M.P.; Tuttle, J.; Shere, A.; Zhao, T. Risk factors for fecal shedding of Escherichia coli O157:H7 in dairy calves. J. Am. Vet. Med. Assoc., 207(1), 46-49, 1995. Risk factors for fecal shedding of Escherichia coli O157:H7 in dairy calves J. Am. Vet. Med. Assoc. 1995 46 49 1 207 Garber L.P. Wells S.J. Hancock D.D. Doyle M.P. Tuttle J. Shere A. Zhao T. 17. Geldreich, E.E.; Fox, K.R.; Goodrich, J.A.; Rice, E.W.; Clark, R.M.; Swerdlow, D.L. Searching for a water supply connection in the Cabool, Missouri disease outbreak of Escherichia coli O157:H7. Water Res., 26, 1127-1137, 1992. Searching for a water supply connection in the Cabool, Missouri disease outbreak of Escherichia coli O157:H7 Water Res. 1992 1127 1137 26 Geldreich E.E. Fox K.R. Goodrich J.A. Rice E.W. Clark R.M. Swerdlow D.L. 18. Giammanco, A.; Maggio, M.; Giammanco, G. Characteristics of Escherichia coli strains belonging to enteropathogenic E. coli serogroups isolated in Italy from children with diarrhea. J. Clin. Microbiol., 34, 689-694, 1996. Characteristics of Escherichia coli strains belonging to enteropathogenic E. coli serogroups isolated in Italy from children with diarrhea J. Clin. Microbiol. 1996 689 694 34 Giammanco A. Maggio M. Giammanco G. 19. Griffin, P.M.; Tauxe, R.V. The epidemiology of infections caused by Escherichia coli O157:H7, other enterohemorrhagic E. coli, and the associated hemolytic uremic syndrome. Epidemiol. Rev., 13, 60-98, 1991. The epidemiology of infections caused by Escherichia coli O157:H7, other enterohemorrhagic E. coli, and the associated hemolytic uremic syndrome Epidemiol. Rev. 1991 60 98 13 Griffin P.M. Tauxe R.V. 20. Hancock, D.D.; Besser, T.E.; Rice, D.H.; Kinsel, M.L.; Tarr, P.I.; Rice, D.H.; Paros, M.G. The prevalence of Escherichia coli O157:H7 in dairy and beef cattle in Washington State. Epidemiol. Infect., 113, 199-207, 1994. The prevalence of Escherichia coli O157:H7 in dairy and beef cattle in Washington State Epidemiol. Infect. 1994 199 207 113 Hancock D.D. Besser T.E. Rice D.H. Kinsel M.L. Tarr P.I. Rice D.H. Paros M.G. 21. Hancock, D.D.; Besser, T.E.; Rice, D.H.; Herriott, D.E.; Tarr, P.I. The longitudinal study of Escherichia coli O157 in fourteen cattle herds. Epidemiol. Infect., 118, 193-195, 1997. The longitudinal study of Escherichia coli O157 in fourteen cattle herds Epidemiol. Infect. 1997 193 195 118 Hancock D.D. Besser T.E. Rice D.H. Herriott D.E. Tarr P.I. 22. Hancock, D.D.; Besser, T.E.; Rice, D.H.; Ebel, E.D., Herriott, D.E., Carpenter, L.V. Multiple sources of Escherichia coli O157 in feedlots and dairy farms in the Northwestern USA. Prev. Vet. Med., 35, 11-19, 1998. Multiple sources of Escherichia coli O157 in feedlots and dairy farms in the Northwestern USA Prev. Vet. Med. 1998 11 19 35 Hancock D.D. Besser T.E. Rice D.H. Ebel E.D. Herriott D.E. Carpenter L.V. 23. Henning, P.H.; Tham, E.B.C.; Martin, A.A.; Beare, T.H.; Jureidini, F.K. Hemolytic-uremic syndrome outbreak caused by Escherichia coli O111:H-: clinical outcomes. Med. J. Aust., 168(11), 552-555, 1998. Hemolytic-uremic syndrome outbreak caused by Escherichia coli O111:H-: clinical outcomes Med. J. Aust. 1998 552 555 11 168 Henning P.H. Tham E.B.C. Martin A.A. Beare T.H. Jureidini F.K. 24. Heuvelink, A.E.; Bleumink, B.; van den Biggllar F.L.A.M.; Giffel, M.C.T. Occurrence and Survival of Verocytotoxin-Producing Escherichia coli O157 in Raw Cow's Milk in the Netherlands. J. Food Prot., 61(12), 1597-1601, 1998. Occurrence and Survival of Verocytotoxin-Producing Escherichia coli O157 in Raw Cow's Milk in the Netherlands J. Food Prot. 1998 1597 1601 12 61 Heuvelink A.E. Bleumink B. van den Biggllar F.L.A.M. Giffel M.C.T. 25. Jackson, S.G.; Goodbrand, R.B.; Johnson, R.P.; Odorico, V.G.; Alves, D.; Rahn, K.; Wilson, J.B.; Welch, M.K.; Khakhria, R. Escherichia coli O157:H7 diarrhea associated with well water and infected cattle on an Ontario farm. Epidemiol. Infect., 120, 17-20, 1998. Escherichia coli O157:H7 diarrhea associated with well water and infected cattle on an Ontario farm Epidemiol. Infect. 1998 17 20 120 Jackson S.G. Goodbrand R.B. Johnson R.P. Odorico V.G. Alves D. Rahn K. Wilson J.B. Welch M.K. Khakhria R. 26. Johnson, R.P.; Clarke, R.C.; Wilson, J.B.; Read, S.C.; Rhan, K.; Renwick, S.A.; Shadu, K.A.; Alves, D.; Karmali, M.A.; Lior, H.; McEwen, S.A.; Spika, J.S.; Gyles, C. Growing concerns and recent outbreaks involving non-O157:H7 serotypes of verotoxigenic Escherichia coli. J. Food Prot., 59, 1112-1122, 1996. Growing concerns and recent outbreaks involving non-O157:H7 serotypes of verotoxigenic Escherichia coli J. Food Prot. 1996 1112 1122 59 Johnson R.P. Clarke R.C. Wilson J.B. Read S.C. Rhan K. Renwick S.A. Shadu K.A. Alves D. Karmali M.A. Lior H. McEwen S.A. Spika J.S. Gyles C. 27. Karmali, M.A. Infection by verotoxin-producing Escherichia coli. Clin. Microbiol. Rev., 2, 15-38, 1989. Infection by verotoxin-producing Escherichia coli Clin. Microbiol. Rev. 1989 15 38 2 Karmali M.A. 28. Kudva, I.T.; Hatfield, P.G.; Hovde, C.J. Effect of diet on the shedding of Escherichia coli O157:H7 in the sheep model. Appl. Environ. Microbiol., 61-4, 1363-1370, 1995. Effect of diet on the shedding of Escherichia coli O157:H7 in the sheep model Appl. Environ. Microbiol. 1995 1363 1370 61-4 Kudva I.T. Hatfield P.G. Hovde C.J. 29. Mechie, S.C.; Chapman, P.A.; Siddons, C.A. A fifteen month study of Escherichia coli O157:H7 in a dairy herd. Epidemiol. Infect., 118, 17-25, 1997. A fifteen month study of Escherichia coli O157:H7 in a dairy herd Epidemiol. Infect. 1997 17 25 118 Mechie S.C. Chapman P.A. Siddons C.A. 30. McGowan, K.L.; Wickersham, E.; Strckbine, N.A. Escherichia coli O157:H7 from water (Letter). Lancet, 1, 967-968, 1989. Escherichia coli O157:H7 from water (Letter) Lancet 1989 967 968 1 McGowan K.L. Wickersham E. Strckbine N.A. 31. Miyao, Y.; Kataoka, T.; Nomoto, T.; Kai, A.; Itoh, T.; Itoh, K. Prevalence of verotoxin-producing Escherichia coli harbored in the intestine of cattle in Japan. Vet. Microbiol., 61, 137-143, 1998. Prevalence of verotoxin-producing Escherichia coli harbored in the intestine of cattle in Japan Vet. Microbiol. 1998 137 143 61 Miyao Y. Kataoka T. Nomoto T. Kai A. Itoh T. Itoh K. 32. Montenegro, M.A.; Bulte, M.; Trumpf, T. Detection and characterization of fecal verotoxin-producing E. coli from dairy cattle. J. Clin. Microbiol., 28, 417-1421, 1990. Detection and characterization of fecal verotoxin-producing E. coli from dairy cattle J. Clin. Microbiol. 1990 417 1421 28 Montenegro M.A. Bulte M. Trumpf T. 33. Orskov, F.; Orskov, I.; Villar, J.A. Cattle the reservoir of verotoxin-producing Escherichia coli O157:H7. Lancet ii, 276, 1987. Cattle the reservoir of verotoxin-producing Escherichia coli O157:H7 Lancet ii 1987 276 Orskov F. Orskov I. Villar J.A. 34. Ostroff, S. M.; Kobayashi, J. M.; Lewis, J. H. Infectious with Escherichia coli O157:H7 in Washington State. The first year of statewide disease surveillance. J. Am. Med. Assoc., 262, 355-359, 1989. Infectious with Escherichia coli O157:H7 in Washington State. The first year of statewide disease surveillance J. Am. Med. Assoc. 1989 355 359 262 Ostroff S. M. Kobayashi J. M. Lewis J. H. 35. Paton, A.W.; Paton, J.C. Detection and Characterization of Shiga Toxigenic Escherichia coli by Using Multiplex PCR Assays for stx1, stx2, eaeA, Enterohemorrhagic E. coli hlyA, rfbO111 and rfbO157. J. Clin. Microbiol., 36(2), 598-602, 1998. Detection and Characterization of Shiga Toxigenic Escherichia coli by Using Multiplex PCR Assays for stx1, stx2, eaeA, Enterohemorrhagic E. coli hlyA, rfbO111 and rfbO157 J. Clin. Microbiol. 1998 598 602 2 36 Paton A.W. Paton J.C. 36. Paton, A.W.; Paton, J.C. Direct detection of Shiga Toxigenic Escherichia coli. Strains Belonging to Serogroups O111, O157 and O113 by Multiplex PCR. J. Clin. Microbiol., 37(10), 3362-3365, 1999. Direct detection of Shiga Toxigenic Escherichia coli. Strains Belonging to Serogroups O111, O157 and O113 by Multiplex PCR J. Clin. Microbiol. 1999 10 37 Paton A.W. Paton J.C. 37. Paton, A.W.; Ratcliff, R.M.; Doyle, R.M.; Symour Murray, J.; Davos, D. Lanser, J.A., Paton, J.C. Molecular microbiological investigation of an outbreak of hemolytic-uremic syndrome caused by dry fermented sausage contaminated with Shiga-like-toxin-producing Escherichia coli. J. Clin. Microbiol., 34, 1622-1627, 1996. Molecular microbiological investigation of an outbreak of hemolytic-uremic syndrome caused by dry fermented sausage contaminated with Shiga-like-toxin-producing Escherichia coli J. Clin. Microbiol. 1996 1622 1627 34 Paton A.W. Ratcliff R.M. Doyle R.M. Symour Murray J. Davos D. Lanser J.A. Paton J.C. 38. Paton, A.W.; Woodrow, M.C.; Doyle, R.M.; Lanser, J.A. Paton, J.C. Molecular characterization of the Shiga Toxigenic Escherichia coli O113:H21 strain lacking eae responsible for a cluster of cases of hemolytic-uremic syndrome. J. Clin. Microbiol., 37(10), 3357-3361, 1999. Molecular characterization of the Shiga Toxigenic Escherichia coli O113:H21 strain lacking eae responsible for a cluster of cases of hemolytic-uremic syndrome J. Clin. Microbiol. 1999 3357 3361 10 37 Paton A.W. Woodrow M.C. Doyle R.M. Lanser J.A. Paton J.C. 39. Porter, J.; Mobbs, K.; Hart, C.A.; Pickup, J.R.; Edwards, C. Detection, distribution and probable fate of Escherichia coli O157 from asymptomatic cattle on the dairy farm. J. Appl. Microb., 83, 297-306, 1997. Detection, distribution and probable fate of Escherichia coli O157 from asymptomatic cattle on the dairy farm J. Appl. Microb. 1997 297 306 83 Porter J. Mobbs K. Hart C.A. Pickup J.R. Edwards C. 40. Rahn, K.; Renwick, S.A.; Johnson, R.P.; Wilson, J.B.; Clarke, R.C.; Alves, D.; McEwen, S.; Lior, H.; Spika, J. Persistence of Escherichia coli O157:H7 in dairy cattle and the dairy farm environment. Epidemiol. Infect., 119, 251-259, 1997. Persistence of Escherichia coli O157:H7 in dairy cattle and the dairy farm environment Epidemiol. Infect. 1997 251 259 119 Rahn K. Renwick S.A. Johnson R.P. Wilson J.B. Clarke R.C. Alves D. McEwen S. Lior H. Spika J. 41. Rose, J.B. Environmental sampling for waterborne pathogens: Overview of methods, application limitations and data interpretation. In: Craun, G.F. (Ed.) Methods for the investigation and prevention of waterborn disease outbreaks. Cincinnati, Ohio: Health Effects Research Laboratory, U. S. Environ. Prot. Agency, 223-234, 1990. Methods for the investigation and prevention of waterborn disease outbreaks 1990 223 234 Rose J.B. Craun G.F. 42. Samadpour, M.; Liston, J.; Ongerth, J.E.; Tarr, P.I. Evaluation of DNA probes for detection of Shiga-like-toxin-producing Escherichia coli in food and calf fecal samples. Appl. Environ. Microbiol., 56, 1212-1215, 1990. Evaluation of DNA probes for detection of Shiga-like-toxin-producing Escherichia coli in food and calf fecal samples Appl. Environ. Microbiol. 1990 1212 1215 56 Samadpour M. Liston J. Ongerth J.E. Tarr P.I. 43. Sanz, M.E.; Vinas, M.R.; Parma, A.E. Prevalence of bovine verotoxin-producing Escherichia coli in Argentina. Euro. J. Epidemiol., 14, 399-403, 1998. Prevalence of bovine verotoxin-producing Escherichia coli in Argentina Euro. J. Epidemiol. 1998 399 403 14 Sanz M.E. Vinas M.R. Parma A.E. 44. Sparling, P.H. Escherichia coli O157:H7 outbreaks in the United States, 1982-1996. J. Am. Vet. Med. Assoc., 213(12), 1733, 1998. Escherichia coli O157:H7 outbreaks in the United States, 1982-1996 J. Am. Vet. Med. Assoc. 1998 12 213 Sparling P.H. 45. Swerdlow, D.L.; Woodruff, B.A.; Robert, C.B.; Griffin, P.M.; Tippen, S.; Donnell, H.D.; Geldreich, E.; Payne, B.J.; Meyer, A.; Wells, J.G.; Greene, K.D.; Bright, M.; Bean, N.H.; Blake P.A. The waterborne outbreak in Missouri of Escherichia coli O157:H7 associated with bloody diarrhea and death. Ann. of Intern. Med., 117(10), 812-819, 1992. The waterborne outbreak in Missouri of Escherichia coli O157:H7 associated with bloody diarrhea and death Ann. of Intern. Med. 1992 812 819 10 117 Swerdlow D.L. Woodruff B.A. Robert C.B. Griffin P.M. Tippen S. Donnell H.D. Geldreich E. Payne B.J. Meyer A. Wells J.G. Greene K.D. Bright M. Bean N.H. Blake P.A. 46. Tzipori, S.; Wachsmuth, K.I.; Smithers, J.; Jackson, C. Studies in gnobiotic piglets on non-O157:H7 Escherichia coli serotypes isolated from patients with hemorrhagic colitis. Gastroenterology, 94, 590-597, 1988. Studies in gnobiotic piglets on non-O157:H7 Escherichia coli serotypes isolated from patients with hemorrhagic colitis Gastroenterology 1998 590 597 94 Tzipori S. Wachsmuth K.I. Smithers J. Jackson C. 47. Vold, L.; Klungseth Johansen, B.; Kruse, H.; Skjerve, E.; Wasteson, Y. Occurrence of Shigatoxigenic Escherichia coli O157 in Norwegian cattle herds. Epidemiol. Infect., 120, 21-28, 1998. Occurrence of Shigatoxigenic Escherichia coli O157 in Norwegian cattle herds Epidemiol. Infect. 1998 21 28 120 Vold L. Klungseth Johansen B. Kruse H. Skjerve E. Wasteson Y. 48. Wells, J.G.; Shipman, L.D.; Greene, K.D.; Sowers, E.G.; Green, J.H.; Cameron, D.N.; Downes, F.P.; Martin, M.L.; Griffin, P.M.; Ostroff, S.M.; Potter, M.E.; Tauxe, R.V.; Wachsmuth, I.K. Isolation of Escherichia coli serotype O157:H7 and other Shiga-like-toxin-producing E. coli from dairy cattle. J. Clin. Microbiol., 29, 985-989, 1991. Isolation of Escherichia coli serotype O157:H7 and other Shiga-like-toxin-producing E. coli from dairy cattle J. Clin. Microbiol. 1991 985 989 29 Wells J.G. Shipman L.D. Greene K.D. Sowers E.G. Green J.H. Cameron D.N. Downes F.P. Martin M.L. Griffin P.M. Ostroff S.M. Potter M.E. Tauxe R.V. Wachsmuth I.K. 49. Willshaw, G.A.; Scotland, S.M.; Smith, H.R.; Cheasty, T.; Thomas, A., Rowe, B. Hybridization of strains of Escherichia coli O157 with probes derived from the eaeA gene of enteropathogenic E. coli and the eaeA homolog from a Vero cytotoxin-producing strain of E. coli O157. J. Clin. Microbiol., 32, 897-902, 1994. Hybridization of strains of Escherichia coli O157 with probes derived from the eaeA gene of enteropathogenic E. coli and the eaeA homolog from a Vero cytotoxin-producing strain of E. coli O157 J. Clin. Microbiol. 1994 897 902 32 Willshaw G.A. Scotland S.M. Smith H.R. Cheasty T. Thomas A. Rowe B. 50. Wilson, J.B.; McEwen, S.A., Clarck, R.C. Distribution and characteristics of verotoxigenic Escherichia coli isolated from Ontario dairy cattle. Epidemiol. Infect., 108, 423-439, 1992. Distribution and characteristics of verotoxigenic Escherichia coli isolated from Ontario dairy cattle Epidemiol. Infect. 1992 423 439 108 Wilson J.B. McEwen S.A. Clarck R.C. 51. Zhao, T.; Doyle, M.P.; Shere, J.; Garber, L. Prevalence of enterohaemorrhagic Escherichia coli O157:H7 in the survey of dairy herds. Appl. Environ. Microbiol., 61, 1290-1293, 1995. Prevalence of enterohaemorrhagic Escherichia coli O157:H7 in the survey of dairy herds Appl. Environ. Microbiol. 1995 1290 1293 61 Zhao T. Doyle M.P. Shere J. Garber L.