An in vitro study on methicillin and other antimicrobial agents against staphylococcus aureus, 1994 - 1996

Staphylococcus aurous infections remain a throat lo bolh immunocompelent and imrnunosuppresscd patients despite advances in antibacterial therapy. An in virro antimicrobial susceptibility study was conducted at the Lagos University Teaching Hospital on clinical isolates of S. aureus over a period of three-years, 1994 . 1996. Beta· lactamase production was detected usina a cnrornoqenic cephalosporin method (Nitrocefin, Oxoicl) and antibiotic susceptibility testing was performed by r ' ct (AB Biodisk, Solna, Sweden) including reference sir;,, ·,. A total of 152 strains of S. aureus were analysed. Eighly-six percent of lhe 152 isolates produced B· lactamase, 50.4% were high level penicillinaso producers, while 4 7 .3°/o produced low levol penicillinasos. Approximately 52% of the strains were sonsilivo lo menu­ cillin and 3.3% to Penicillin G. Thero was 100% suscopfi­ bility to vancomycin over the three ye,r period, 96.5% lo rifampin, 90.2°/o to tusidic acid, 89.6°/o to ctindamycin, 71.8°/o to amoxycillin-ctavulanic acid, 7 1 . 7°/o lo cry­ lhromycin, 64.4°/o to cotrimoxazolo, and below 50°/o lo gentamicin and tctracv: line. The MIC90 values for vancomycin, clindamycin, rifampin and fusidic acid were within tho.; susceptible break­ points, thus these drugs could be used omp\rically. For the other antibiotics tested such as eryth�omycin, tetracycline, augmentin, septrin and gentamicin, susceptibility cannot be assumed. In vitro efficacy should volioate their therapeulic option. ·