Isolation and Identification of toxigenic strains of E.coli from local cheese and evaluate their resistance to antibiotics

Abstract

Raw milk cheese is considered a srisk for food borne shiga-toxin-producing E.coli (STEC) contamination .The aim of the study is to isolation and identification of isolated strains by using serological and molecular methods.In this study 60 raw milk cheese samplas were collected from different local of Baghdad city (each 10 sample from each region of Baghdad) such as (Algadeda Baghdad,Gesser Diyala.Fudhaliyah.sader city.Kadhimiyh area and Rashid district)The isolated samples were cullured in selective media for identification and biochemical tests by using API 20 E and also by PCR technique for the presence of (STEC) by using bfp gene markers (stx1,stx2). The results showed the presence of E.coli 0.26 haemorrhagic type (EHEC) and the Enteropathogenic strain of E.coli (0.86,0.127.0.128) and the Enteroaggregative strain of E.coli (0.55). On the level of serological the isolates gave positive result that indicate presence of shiga toxin (stx1.stx2)in raw milk cheese .The result also showed multiple resistant of certain antibiotic(Amicillin 100%, Nalidixic acid and tetracycline and Gentamicin 80%, while was observed sensitive to Amikacin 100% and trimethoprim and cefotaxin 80.