Prevalence of High Level Gentamicin Resistance among the Clinical Isolates of Enterococci Species

Abstract

Enterococci infections, have drawn attention of clinicians due to rapid increase in high level aminoglycoside resistance (HLAR). This resistance predicts failure of β-lactam antibiotic and aminoglycoside combination, which is the current treatment of choice for serious enterococci infections. This led us to investigate about the prevalence of HLAR enterococci in our hospital setting in Shimoga, Karnataka. All the clinical samples received at Microbiology laboratory, McGan hospital, Shivamogga between June 2016 and December 2016 was considered for the study. Enterococci were identified and further speciated by following conventional method. Antibiotic susceptibility pattern of all the isolates was determined according to CLSI guidelines. High level gentamicin resistance was detected by disc diffusion method using 120µg gentamicin disc. A total of 64 Enterococci species were isolated from the clinical specimens. On speciation, Enterococcus faecalis (E. faecalis) accounted for 72% (46) of the total isolates, 24%(16) of the isolates were Enterococcus faecium (E. faecium)and 4% (2) isolates were Enterococcus durans (E. durans). High level gentamicin resistance was noted in 42% (27) among the total isolates. E. faecium was found to be more resistant compared to E. faecalis. E. durans was a sensitive strain. Our study reconfirms the high prevalence of HLAR in the clinical setting. The study stresses on the need for regular screening of HLAR in all Enterococci infections and revise the battery of drugs for its treatment according to the report.