Identification of Shiga-toxin producing Escherichia coli (STEC) from precooked sausages (morcillas) in San Luis, Argentina

GABRIEL A. SALINAS-IBAÑEZ; FAVIER GABRIELA ISABEL; LUCERO ESTRADA CECILIA STELLA MARYS; MATTAR AIDA; STAGNITA, PATRICIA; ALBA E. VEGA; 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

Infection by Shiga toxin-producing Escherichia coli (STEC), a foodborne enteropathogen, may result in watery or bloody diarrhea, and hemolytic uremic syndrome. In our country, the search of STEC O157:H7 in meat sold at retail markets is mandatory. It is only know one previous study in Argentina which reported a 3% of STEC prevalence in "morcillas". Twenty seven samples of this food collected from butcher shop of San Luis city during 2013, were analyzed. They were enriched in trypticase soy broth (TSB) and concentrated by using immunomagnetic particles coated with E. coli O157:H7 antibodies (IMP). Then, 50 µl TSB/IMP were plated onto Sorbitol Mac Conkey agar (SMAC) and other 50 µl TSB/IMP was directly used for DNA extraction. The extracted DNA after TSB/IMP, TSB/IMP/SMAC and TSB/SMAC, was screened for genes of Shiga toxins 1 and 2 by duplex PCR. Six samples (22.2%) were stx1+ or stx2+; five of them (18.51%) were positive from TSB/IMP, three (11.1%) from TSC/IMP/SMAC and two (7.40%) from TSB/SMAC. The stx2 sequence was 2.3 times more frequently detected tha stx1. These results indicate the high risk of STEC transmission by morcillas in San Luis. These sausages should be considered unsafe for consumers when they are inadequately cooked.