Antimicrobial resistance of Enterococci in Lebanon

There is little information on the types of Enterococcus spp and their antibiotic resistance patterns in Lebanon. One hundred and fifty-three consecutive clinical enterococcal isolates collected between 1998 and 1999 were tested against 11 antimicrobial agents using disk diffusion and the Etest. The isolates were identified by conventional methods and API-Strep and were found to consist of Enterococcus faecalis (72.5%), Enterococcus faecium (22.9%), Enterococcus avium (3.2%) and Enterococcus gallinarum (1.3%). The percent of resistant strains of E. faecalis and E. faecium respectively were, ampicillin 0.9 and 14%, erythromycin 59% and 40%, tetracycline 72% and 34%, chloramphenicol 32 and 11%, rifampin 36% and 57%, ciprofloxacin, 23% and 34%, norfloxacin 22 and 8%. High level aminoglycoside (HLA) resistance was found in 19% E. faecalis and 9% E. faecium for gentamicin and 36% and 26% for streptomycin. Excellent correlation was observed between the high level disk tests and the Etest in the detection of HLA resistance but not with the regular disks. None of the isolates showed resistance to vancomycin or teicoplanin except for one E. gallinarum isolate which showed intermediate resistance (MIC 16 mg/l) to vancomycin. These variable antimicrobial rates of resistance suggest a surveillance programme for antimicrobial resistance in this country would be helpful to help control infection, guide empirical antibiotic therapy and implement a policy of antibiotic usage.