Epidemiology and molecular characterization of vancomycin resistant Enterococci isolates in India

Little attention has been paid to the problem of the spread of vancomycin resistant enterococci (VRE) in India. Between August 2002 to March 2003, faecal and urine samples of patients from various wards of the Postgraduate Institute of Medical Education and Research, Chandigarh, India, were screened for vancomycin resistance. 36 VRE were isolated (18 Enterococcus gallinarum, 9 E. casseliflavus, 7 E. faecium and 2 E. faecalis). These isolates were characterized as low-, moderate- and high-level resistant strains by phenotypic as well as genotypic methods such as minimum inhibitory concentration determination, polymerase chain reaction assays, sequencing of PCR products and multiple sequence alignment of van genes. Correlations established between these results and the vancomycin resistance markers were designated as vanA (783 bp), vanB (635 bp), vanC1 (822 bp) and vanC2 (484 bp) according to the findings of earlier workers as well as comparison with existing databases. Prolonged hospital stay and vancomycin were important risk factors for both VRE UTI and colonization. Renal dialysis, renal failure, prior aminoglycoside and third generation cephalosporin were the other significant factors for VRE UTI. The study also highlights the importance of screening for VRE in clinical samples and recommends the institution of control measures to prevent the further spread of VRE.