Antibiotic resistance of Staphylococcus aureus at North Lebanon: Place of the methicillin resistance and comparison of detection methods

The aim of this study was to evaluate the susceptibility of 100 Staphylococcus aureus strains isolated from the laboratory of Microbiology of the Islami Hospital of Tripoli (Lebanon) to 19 antibiotics, and to determine the prevalence of methicillin resistant strains. 30% of strains studied were methicillin resistant, 96% were resistant to the penicillin G. Clavulanic acid restaurated the amoxicillin activity to 29%. The resistance level was 34% for amikacin, 3% for gentamycin and tobramycin, 10% for chloramphenicol, 44.33% for tetracyclin, 7% for erythromycin, 4.04% for clindamycin, 20% for trimethoprim-sulfametoxasol and 0% for vancomycin and teicoplanin. The methicillin-resistant Staphylococcus aureus possess more important resistant level in comparison with the methicillin sensitive strains. We compared the ability of latex agglutination test (Slidex© SARM, bioMérieux, France) to detect the production of penicillin-binding protein 2′ (PBP 2′) in 100 clinical isolates of S. aureus with two reference methods: the oxacillin disk diffusion test and the MIC determination by the E-test (AB BIODISK, Sweden). The two reference methods give the same results for the detection of methicillin resistant S. aureus. The Slidex test was positive for all 30 isolates determined to be methicillin resistant by the reference methods (sensitivity 100%). The latex test was negative for 42 of 70 isolates determined to be methicillin susceptible by the reference methods, and the latex test was positive for 28 isolates determined to be susceptible (specificity 60%). © 2002 Éditions scientifiques et médicales Elsevier SAS. All rights reserved.