Isolation and speciation of enterococci from various clinical samples and their antimicrobial susceptibility pattern with special reference to high level aminoglycoside resistance

Enterococci are important nosocomial agents and strains resistant to penicillin and other antibiotics occur frequently. Enterococci are intrinsically resistant to cephalosporins and offer low level resistance to aminoglycosides. In penicillin sensitive strains, synergism occurs with combination treatment with penicillin and aminoglycoside. Serious infections caused by them are treated with penicillin and aminoglycoside combination. But the synergistic effect is lost, when the strain develops high level aminoglycoside resistance. The choice of drug for infections due to such strains is vancomycin. The present study was carried out to isolate and speciate Enterococci from various clinical samples, to know the susceptibility pattern of the isolates, to determine the High Level Aminoglycoside Resistance (HLAR) among Enterococcal isolates.

A total of One hundred Enterococcal species isolated from various clinical samples were identified by various biochemical reactions. Antimicrobial susceptibility testing and HLAR were determined by Kirby-Bauer disc diffusion method.

Out of 100 Enterococcal isolates, 59 were E. faecalis, 38 were E. faecium, 3 were other Enterococcal species. Among these 53 isolates showed High Level Aminoglycoside Resistance.

Present study shows the presence of drug resistance to most of commonly used antibiotics and HLAR is also more in E.faecium compared to E.fecalis.