Rapid detection of Shiga toxin-producing Escherichia coli O157:H7 from ground beef and sausages in San Luis

GABRIEL A. SALINAS-IBAÑEZ; FAVIER GABRIELA ISABEL; LUCERO ESTRADA CECILIA STELLA MARYS; MATTAR AIDA; STAGNITA, PATRICIA; VEGA ALBA; ESCUDERO MARÍA ESTHER; TERESA I. CORTIÑAS

Mendoza

Jornada; XXXI Reunión Científica Anual de la Sociedad de Biología de Cuyo; 2013

Sociedad de Biología de Cuyo

Shiga toxin-producing Escherichia coli (STEC), a foodborne pathogen with a high prevalence in Argentina, is associated with human diseases such as bloody diarrhea and hemolytic uremic syndrome, being the serotype O157:H7 the most prevalent. The pathogenic potential of STEC is related to the production of Shiga toxin 1 and 2. A procedure for the fast detection of this pathogen in products sold in butcher shops in San Luis city is presented. Eighty samples of ground beef and sausages collected from April to August 2013 were analysed as follows: 20 g samples were enriched in 80 ml of tryticase soy broth (TSB) for 24 h at 37°C. Then, 18 µl of immunomagnetic particles coated with E. coli O157:H7 antibodies (IMP) were added to 1 ml enriched TSB and immunoseparated. DNA was extracted and duplex PCR targeting genes stx1/stx2 was performed. Sequences of 130 (stx1) and 346 (stx2) bp were amplified. The stx2 gene was detected in 12 samples (15%). Four out of these samples were also stx2+ by PCR after culture on Sorbitol Mac Conkey agar. Although DNA of nonculturable bacteria might be detected by using IMP followed by PCR, positive results obtained by this specific and rapid procedure are indicative for the presence of STEC in meat samples in our region.