Abstract A total of fifty seven isolates of Entercoccus faecalis (N=42) and E. faecium (N=15) from infected wounds were screened for their resistance against 17 antibiotics including vancomycin. E. faecalis isolates demonstrated absolute resistance (100%) against eight antibiotics: chloramphenicol, nalidixic acid, gentamicin, streptomycin, tetracyclin, erythromycin, penicillin G and lincomycin. While isolates of E. faecium revealed absolute resistance (100%) to only three antibiotics: chloramphenicol, nalidixic acid, and lincomycin, yet they exhibited 80% resistance against gentamicin and streptomycin. Higher percentage of resistance against vancomycin was shown by E. faecium (53.3%) as compared to Ent. faecalis (47.6%). E. faecalis and E. faecium isolates were involved in 5 and 2 antibiotic resistance patterns (ARPs) respectively. Of the two species; 24.5% isolates (N=11, 26.2% E. faecalis and N=3, 20% E. faecium )were included in one ARP demonstrating resistance to all antibiotics under study.
High-level resistance to glycopeptides (HLRG) vancomycin (64 µg/ml) was higher among isolates of E. faecium (50%) as compared to E. faecalis (30%). Whereas high-level resistance to aminoglycosides (HLRA): gentamicin (500 µg/ml) and streptomycin (>1000 µg/ml) was higher among E. faecalis against gentamicin (80% VS 62.5%) and almost similar incidence was reported by the two species against streptomycin (60% and 62.5% respectively). Emergence of varied ARPs and high-level resistance to vancomycin and aminoglycosides among E. faecalis and E. faecium isolates will reduce to a great extent the therapeutic options against enterococcal infections. Hence, we emphasizes on the importance of performing susceptibility testing on all clinically significant isolates.
Keywords Entercoccus faecalis, E. faecium, Antibiotic resistance patterns, High level resistance to glycopeptides, High level resistance to aminoglycosides.