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

MASANA M.O; DASTEK B.A; PALLADINO P.M; GALLI L; DEL CASTILLO L.L; CARBONARI C; LEOTTA G.A; VILACOBA E; IRINO K; RIVAS M

JOURNAL OF FOOD PROTECTION

INT ASSOC FOOD PROTECTION

Año: 2011 vol. 74 p. 2008 - 2017

0362-028X

The non-O157 STEC contamination in carcasses and feces of 811 bovines was analyzed, during a period of 17 months, in nine beef abattoirs from. 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 HUS in Argentina and worldwide. Twenty-two (7.2%) strains carried a full virulence genotype. Among them, strains of O145:NM, and O111:NM serotypes represented 4.8% of the isolates. XbaI-PFGE pattern analysis showed 234 different patterns, with 76 strains grouped in 30 clusters. Nine clusters grouped strains isolated from feces, and carcasses in one lot, while three clusters were composed by strains distributed in more than one abattoir. Patterns AREXSX01.0157, AREXBX01.0015, and AREXPX01.0013 were identified as 100% compatible with patterns of one strain isolated from an HUS case, and two strains previously isolated from beef medallions, included in the Argentine PulseNet Database. In this survey, 4.8% (39/811) of the bovine carcasses appeared contaminated with non-O157 STEC strains potentially capable of producing sporadic human diseases, and in a lower proportion (0.25%) with strains able to produce outbreaks of severe disease