COMPARATIVE IN-VITRO ACTIVITY OF 9 ANTISTAPHYLOCOCCAL AGENTS AGAINST 275 RECENT ISOLATES OF GRAM-POSITIVE COCCI

The aim of this study was to compare the in vitro activities of 9 anti staphylococcal agents including teicoplanin (TEI) against 275 non-repe titive clinical strains representing 15 species of staphylococci and 2 7 strains of Enterococcus (E.) faecalis, isolated from various specime ns between 1991-1992 at a Canadian teaching hospital. The NCCLS agar d ilution method was used (10(4) colony-forming units/spot). In terms of MIC(90), TEI and vancomycin (VAN) appeared to be the most potent anti biotics against all staphylococci tested (TEI: 2.0-4.0 mu g/ml; VAN: 1 .0-2.0 mu g/ml; ciprofloxacin (CPF): 0.25-32 mu g/ml; cefazolin (CEF): 8.0-256 mu g/ml; methicillin (MET): 2.0->256 mu g/ml; imipenem (IMP): 1.0-32 mu g/ml; erythromycin (ERT): 16->256 mu g/ml; ampicillin (AMP) : 16-128 mu g/ml; fusidic acid (FSA): 0.5-16 mu g/ml). Multiple resist ant strains, including MET-resistant Staphylococcus (Staph.) aureus an d Staph. epidermidis, were susceptible to TEI and VAN with respective MICs of 2-4 mu g/ml and 1-2 mu g/ml regardless of specimen type. Moreo ver, TEI was highly active against E. faecalis (MIC(90) for TEI and VA N: 0.5 and 4.0 mu g/ml, respectively).