clonal diversity in multi drug resistant (mdr) enterococci isolated from fecal normal flora

enterococci are gram positive and catalase- negative cocci that are found in the gastrointestinal tract of mammals and birds, and are readily isolated from soil, surface and waters. the aim of this study was to discriminate between enterococcus isolates based on repetitive element sequence based –pcr (rep-pcr) with the boxa2r primer and their antibiotics profile. enterococci isolates were obtained from 180 fecal samples. the isolates were identified by biochemical reaction and specific identification was confirmed by pcr with species specific primers. all isolates were subjected to rep typing and antimicrobial susceptibility tests. rep-pcr analysis of 180 isolates revealed 93 rep types with forty-five single types (st1 to st45) and forty-eight common types (ct1 to 48). antibiotic susceptibility tests exhibited that 53 (29.4%), 43 (23.8%), 11 (6.1%) and 9 (5%) were resistant to erythromycin, tetracycline, gentamicin and ciprofloxacin respectively but among the isolates, sixteen were multi drug resistant (mdr). these mdr isolates showed 11 rep types with seven single types and four common types. in addition, 81.2% of mdr isolates were from male subjects and the average age of these persons was more than fifty years. this study showed that 56.2% of mdr isolates were homogeneous with 95 % similarity, and high rate of resistance to tetracycline and erythromycin (81.2%) were observed in these isolates. the concern about these normal flora isolates are the pathogenic potential of these bacteria through the horizontal transfer of antibiotic resistance and virulence genes.