Enhancement of benzyl penicillin activity against staphylococcus aureus in presence of subinhibitory concentration of surfactants

ABSTRACT

Abscess causative agents were isolated from 17 patients. Sixty-four bacterial isolates were identified as Staphylococcus aureus. Fifty-seven of these S. aureus were penicillinase producers. Incorporation of subinhibitory concentrations of cetrimide or sodium dodecyl sulfate [SDS] in the nutrient agar increased the diameter of the inhibition zones of benzyl penicillin discs. Incorporation of subinhibitory concentrations of SDS in the liquid broth also decreased the MICs benzyl penicillin, ampicillin and carbenicillin against penicillinase positive S. aureus. Combining a subinhibitory concentration of cetrimide or SDS with benzyl penicillin in liquid culture of S. aureus reduced the culture turbidity and cell viability. It was evident that, surfactant at subinhibitory concentrations enhance the activity of benzyl penicillin against penicillinase producing Staphylococcus aureus