MOLECULAR CHARACTERIZATION OF SHIGA TOXIN-PRODUCING Escherichia coli ISOLATED FROM THE ENVIRONMENT OF A DAIRY FARM

POLIFRONI, ROSANA; ETCHEVERRÍA, ANALÍA I.; SANZ, MARCELO E.; CEPEDA ROSANA; KRÜGER, ALEJANDRA; LUCCHESI, PAULA M. A.; FERNÁNDEZ, DANIEL; PARMA, ALBERTO E.; PADOLA, NORA L.

CURRENT MICROBIOLOGY

SPRINGER

Lugar: Nueva York; Año: 2012 vol. 65 p. 337 - 343

0343-8651

Environmental samples were taken from soil, cattle water troughs and feeders from a dairy farm with different STEC prevalence between animal categories (weaning calves, rearing calves and dairy cows). The stx genes were investigated by PCR. The 23 % of samples was positive for stx genes, being stx2 the most prevalent type. Isolates were analyzed by PCR monoplex to confirm generic E. coli and by two multiplex PCR to investigate the presence of stx1, stx2, eae, saa, ehxA and other putative virulence genes encoded in STEC plasmids, katP, espP, subA and stcE. The toxin genes were subtyped and the strains were serotyped. The soil and the environment of the rearing calves were the sites with the highest number of STEC-positive samples, however cattle water troughs and the environment of cows were the places with the greater chance of finding stx2. 2EDL933 which is a subtype associated with serious disease in humans. Several STEC serotypes non-O157 were detected. The serotypes O8:H19; O26:H11; O26:H-; O118:H2; O141:H- and O145:H- have been asociated with human illness. Furthermore, the emergent pathogen STEC O157:H- (stx1-ehxA-eae) was detected in the environment were weaning calves remained. These results emphasizes the risk that represents the environment as source of STEC potentially pathogen for human and suggest the importance of develop control methods designed to prevent contaminations of food products and transmition animal-person.