Shigatoxigenic Escherichia coli serogroups O157, O111 and O113 in feces, water and milk samples from dairy farms

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 stx 1 , stx 2 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.

Seasonal variation of Shiga toxin-encoding genes (stx) and detection ofE. coliO157 in dairy cattle from Argentina

“…The highest prevalence rates in calves compared to the values obtained in cows (43% vs 37·5%), agree with the results obtained by other authors (Cobbold and Desmarchelier 2000; Vicente et al. 2005), but differ from those obtained by Moreira et al.…”

“…Cattle are generally asymptomatic carriers, shedding these bacteria through their faeces, which in turn may serve as a maintenance medium and spreading these pathogens among cattle herds and environment (Vicente et al. 2005).…”

“…Shiga toxin‐producing E. coli are transmitted to humans through contaminated food by faecal material, mainly undercooked ground beef and unpasteurized dairy products, and person to person contact. Transmission through drinking and recreational water has also been described (Hussein and Sakuma 2005;Vicente et al. 2005; Cho et al.…”

Enterohemorrhagic Escherichia coli O157: H7 from healthy dairy cattle in Mid-West Brazil: occurrence and molecular characterization

“…In Argentina, Tanaro et al (2010) found that 11 out of the 288 (3.8%) fecal samples were O157 positive. In Brazil, Vicente et al (2005) found a prevalence as high as 18.9% (86/454) for serogroup O157 in some herds in São Paulo State. However, Sandrini et al (2007) reported a prevalence of less than 0.3% (3/1127) in dairy cattle from Rio Grande do Sul State and Cerqueira et al (1999) observed a prevalence of 1.5% (3/197) for O157:H7 in healthy dairy cattle from Rio de Janeiro State.…”

Shiga toxin‐producingEscherichia coliin the animal reservoir and food in Brazil

“…On the other hand, the stx1/stx2 genotype was the prevalent one in studies conducted in the same region by Cerqueira et al (, ) and Irino et al () with dairy cattle; Joaquim et al () with cattle (dairy or beef), Oliveira et al () with beef cattle and dairy goats and Vettorato et al (, ) and Maluta et al () with sheep. The stx2 genotype predominated in studies of Vicente et al () and Oliveira et al () with dairy cattle and Beraldo et al () with dairy buffalos.…”