Molecular detection of vanA gene in staphylococcus aureus isolated from stool samples in North India

Abstract EN

Staphylococci spp.

were isolated from 163 stool samples collected from patients in the period from January through August 2007.

The isolates included 52 (31.9%) Staphylococcus aureus and 111 (68.1%) coagulase negative staphylococci (CoNS) were subjected to minimum inhibitory concentration (MIC) test against vancomycin and teicoplanin.

Only four S.

aureus strains were resistant to vancomycin (MIC = 16-64 mg/ml) and teicoplanin (MIC = 32-128 mg/ml).

No CoNS isolate exhibited resistance to vancomycin and teicoplanin.

Disc diffusion test for vancomycin-resistant Staphylococcus aureus isolates showed high resistance (100%) to ampicillin, ciprofloxacin, erythromycin, oxacillin, penicillin, tetracycline, teicoplanin and vancomycin; they were resistance to clindamycin and streptomycin (75%), and resistance to chloramphenicol and gentamicin (50%).

Multiplex PCR assay for the vanA and vanB genes showed that only 4 isolates with the VanA phenotype produced the expected molecular size 1030 bp product corresponding for the vanA gene.

None of the remain isolates produced positive results with the vanA or vanB primers