Frequency of Shiga toxin-producing Escherichia coli (STEC) isolates among diarrheic and non-diarrheic calves in Brazil

Leomil, Luciana; Aidar-Ugrinovich, L.; Guth, Beatriz E. C.; Irino, Kinue; Vettorato, M.P.; Onuma, Daniela Lopes; Castro, Antonio Fernando Pestana de

doi:10.1016/j.vetmic.2003.08.002

Cited by 83 publications

(108 citation statements)

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“…Wieler et al (1996) determined the prevalence of both virulence factors in STEC as of 70.0%; Cobbold and Desmarchelier (2000) described only 0.8% positive eae's among STEC isolates. Salvadori et al (2003) and Leomil et al (2003) reported a frequency of eae carriage of 21.2% and 41.0% respectively, among STEC isolates from calves in Brazil; in the present study, however, only a small number of isolates had this gene (2.3%). Wieler et al (1996) described that most of the STEC strains from diarrheic calves harbor stx1 genes along with the eae gene.…”

Section: Discussioncontrasting

confidence: 75%

“…Colibacillosis is common in Brazil, as some studies have reported (Leomil et al, 2003;Salvadori et al, 2003). Among the 173 E. coli isolates studied from northwestern of São Paulo State, 85 (49.1%) were found to be positive for at least one of the virulence factors examined, a result similar to that reported by Salvadori et al (2003).…”

Section: Discussionsupporting

confidence: 73%

“…Studies carried out in different countries have shown that 10-80% of cattle may carry STEC (Blanco et al, 1996;Cobbold and Desmarchelier, 2000). STEC was found in 9 isolates (5.2%); this value is smaller than that reported by Leomil et al (2003), of 12.7% of STEC strains, and by Salvadori et al (2003), 16.1%, both from Brazil.…”

Section: Discussioncontrasting

confidence: 62%

“…High frequency of STEC has been observed in isolates from diarrheic and non-diarrheic calves (Leomil et al, 2003). Studies carried out in different countries have shown that 10-80% of cattle may carry STEC (Blanco et al, 1996;Cobbold and Desmarchelier, 2000).…”

Section: Discussionmentioning

confidence: 99%

“…E. coli producing Stx 1 and/or 2, causes the hemorrhagic colitis (HC) and the hemolytic-uraemic syndrome (HUS) in humans. Most cases of these diseases are caused by the ingestion of foods and drinks contaminated with cattle feces, especially ground beef, undercooked hamburgers, salami, raw milk or home made raw milk cheese (Paton and Paton, 1998;Nataro and Kaper, 1998). Epidemiological investigation shown that sick as well as apparently healthy cattle constitute a natural reservoir of these microorganisms, frequently excreted in their feces, representing a possible source of infection (Blanco et al, 1996).…”

Section: Introductionmentioning

confidence: 99%

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Virulence factors of Escherichia coli isolated from diarrheic calves

Rigobelo

Gámez

Marin

et al. 2006

Arq. Bras. Med. Vet. Zootec.

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One hundred seventy-three Escherichia coli strains isolated from calves from northwestern São Paulo State, having diarrhea were examined for the production of thermolabile (LT) and thermostable (ST) enterotoxins and for the presence of virulence factors associated with bovine colibacillosis. Eighty-five (49.1%) of the E.coli strains produced toxins; 53 isolates were detected as producing STa toxin, and 9 also produced LT toxin. By PCR, 23 isolates were shown to harbor only the LT-II gene. Nine (5.2%) isolates harbored Shiga toxin genes: four carried the stx2 gene, four the stx1 gene and one carried both. Three of the isolates showing stx1 also carried the eae gene. Among the E. coli isolates examined for susceptibility to 10 antimicrobial agents, resistance to cephalothin (46.1%), was most commonly observed, followed by resistances to tetracycline (45.7%), trimethoprim-sulfadiazine (43.3%) and ampicilin (41.0%). All isolates showed resistance to at least two antimicrobial agents; multidrug resistance was quite frequently encountered. Results showed that bovine E. coli produces some toxins and virulence factors, some of which may be involved in human disease. The isolates showed a high level of resistance to antimicrobial agents constituting a public health concern.Keywords: calf, diarrhea, Escherichia coli, virulence factor, antimicrobial agent RESUMO Cento e setenta e três cepas de Escherichia coli isoladas de bezerros com diarréia provenientes da região noroeste do estado de São Paulo foram examinadas para a produção de enterotoxinas termolábil (LT) e termoestável (ST), e examinadas quanto à presença de fatores de virulência associados a colibacilose bovina. Oitenta e cinco (49,1%) das cepas de E. coli produziram toxinas, 53 cepas foram detectadas como produtoras de toxina STa, e nove dessas cepas também produziam toxina LT. Foram identificadas pela reação em cadeia de polimerase 23 cepas portadoras do gene LT-II. Nove (5,2%) das cepas apresentavam os genes de toxina

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Section: Discussioncontrasting

confidence: 75%