Occurrence of toxigenic Escherichia coli in raw milk cheese in Brazil

Abstract

The occurrence of toxigenic Escherichia coli in raw milk cheese was surveyed in Middle Western Brazil. Fifty samples of cheese from different supermarkets were analyzed for E.coli. The isolates were serotyped and screened for the presence of verotoxigenic E. coli (VTEC) and enterotoxigenic E. coli (ETEC) by Polymerase Chain Reaction (PCR). The susceptibility to thirteen antimicrobial agents was evaluated by the disk diffusion method. E.coli were recovered from 48 (96.0%) of the samples. The serogroups identified were O125 (6.0%), O111 (4.0%), O55 (2.0%) and O119 (2.0%). Three (6.0%) and 1(2.0%) of the E.coli isolates were VTEC and ETEC, respectively. Most frequent resistance was observed to the following antimicrobials: cephalothin (60.0%), nalidixic acid (40.0%), doxycyclin (33.0%), tetracycline (31.0%) and ampicillin (29.0%). Keywords: Escherichia coli, cheese, VTEC, ETEC, antimicrobial resistance RESUMO Pesquisou-se a ocorrência de

Analysis of virulence genes in Escherichia coli isolated from grated cheese

“…The low prevalence of pathogenic E. coli in cheese, in spite of the large contamination by faecal coliforms, has been previously stated (PANETO et al, 2007;GONZALEZ et al, 2000); it was suggested that pathogenic E. coli could have been present as a small fraction of the coliform population and could have been overgrown by other strains (CONEDERA et al, 2004). This statement might explain the low percentage of strains carriers of virulence genes observed in this work.…”

“…Soft and semi-soft cheeses have been previously associated with disease outbreaks involving pathogenic strains of E. coli (PANETO et al, 2007;QUINTO;CEPEDA, 1997). However, little information about the presence of these microorganisms in grated cheese is available.…”

“…According to Paneto et al (2007), CNF-producing E. coli (NTEC) have been rarely found in Brazil. However, 7.81% of the strains analyzed in this study were carriers of the cnf2 gene.…”

“…ETEC causes diarrhoea by adhering to the intestinal mucosa through its unique colonization factors and produces either heat-labile enterotoxins (LT-I and LT-II) or heat-stable enterotoxins (STa and STb), or both (PANETO et al, 2007). Virulent EPEC often exhibit a typical adherence phenotype to epithelial cells (localized adherence -LA) and induce attaching-effacing (A/E) lesions on gut enterocytes.…”

Molecular characterization and evaluation of antimicrobial susceptibility of enteropathogenic E. coli (EPEC) isolated from minas soft cheese

“…The presence of pathogenic E. coli strains in Minas soft cheese has been reported by several studies (NASCIMENTO; SABIONI; PIMENTA, 1988;PANETO et al, 2007).…”