Isolation and species identification of enterococci from clinical specimen with their antimicrobial susceptibility pattern in a tertiary care hospital,Bangladesh

Objective:To investigate the species prevalence of Enterococcus with their antimicrobial resistance pattern from patients of Dhaka Medical College Hospital.Methods:Samples were cultured and Enterococcus species were identified by conventional biochemical tests as well as PCR by using species specific primers for Enterococcus faecalis(E.faecalis)and Enterococcus faecium(E.faecium).For isolation of vancomycin resistant enterococci,minimum inhibitory concentration of vancomycin and PCR was done to detect vanA and vanB genes.Results:A total of 16 enterococci were isolated from 300 urine and 200 wound swab samples(15 from urine and 1 from wound swab)from July 2011 to June 2012.Enterococci were the third most common organism(8.47%)from urine after Escherichia coli(63.28%)and Enterobacter(11.87%).Out of 16 enterococci,10(62.5%)were E.faecalis,4(25%)were E.faecium and 2(12.5%)were other species.All the enterococci(100%)were sensitive to vancomycin and linezolid.Most of the strains were resistant to ciprofloxacin and azithromycin(87.5%),gentamycin(81.25%),ceftriaxone(75%),amoxiclav(31.25%)and imipenem(25%).E.faecium was more resistant than E.faecalis to azithromycin(100%),ciprofloxacin(100%),amoxiclav(75%)and imipenem(50%).No vancomycin resistant enterococci were identified and the range of minimum inhibitory concentration for vancomycin was 1-4μg/mL.None of the enterococci were positive for vanA and vanB genes.Conclusions:The presence of multidrug resistant enterococci should be considered as danger alarm for serious enterococcal infections and further study in large scale is needed.