Biocides susceptibility pattern and phenotypic detection of Efflux pump in Staphylococcus aureus isolates from two tertiary hospitals of Pakistan

Abstract

This study was conducted on wound isolates, collected both from in-patients and out-patients of two tertiary hospitals of Peshawar, Pakistan. A total of 70 Staphylococcus aureus isolates, including 35 methicillin resistant Staphylococcus aureus (MRSA) and 35 methicillin sensitive Staphylococcus aureus (MSSA) were tested using different biocides and antibiotics. The biocides used in this study were Cetrimide, Benzalkonium chloride, Chlorhexidine, Triclosan, Triclorcarban, PCMX, Cetylpyridinium chloride, Copper sulphate and Silver nitrate while antibiotics used in this study were Erythromycin, Clindamycin Neomycine, Minocycline, Ciproflaxacin, Oflaxacin, Fusidic acid, Vancomycin, Mupiracin, Rifampicin, Chloramphenenicol, Sulfamethoxazole/trimethoprim, Tetracylcine and Penicillin G. Sensitivity of biocides was performed by minimum inhibitory concentrations (MICs) while the antibiotic susceptibility was carried out using Kirby Bauer disc diffusion method. The phenotypic detection of efflux pump was performed by agar dilution method using Ethidium bromide (EtBr). Most of the S. aureus isolates were found highly resistant to antibiotics, while they showed high susceptibility to biocides. Among the biocides tested, only 22.8% isolates showed resistance to Cetrimide. Triclosan was found the most effective biocide which showed MIC 90