Prevalence of Inducible Clindamycin Resistance and Nanotechnological Control of Staphylococcus aureus Clinical Isolates

Abstract

Staphylococcus aureus (S. aureus) is one of the pathogens that may cause a wide range of infections in humans. Clindamycin has been considered as an important medication in treating these infections especially skin and soft tissue infections. Inducible clindamycin resistance (ICR) is a complication in treating S. aureus infections in humans. It is difficult to detect S. aureus strains expressing ICR by using standard susceptibility test methods. Recently, there is an increasing need to find alternatives to antibiotics. Nanoparticles, especially silver nanoparticles, were reported as potential alternatives for traditional antibiotics (or in combination with traditional antibiotics) against the emergence of bacterial multidrug resistance. This research aimed to study the prevalence of ICR among S. aureus clinical isolates and investigate the antibacterial effects of AgNPs solely and in combination with clindamycin against these isolates with evaluation of the acute toxicity of intraperitoneal administrated silver nanoparticles (AgNPs). Out of one hundred isolates of S. aureus studied over a period of one year, 70 isolates were identified as MRSA and 30 isolates were MSSA. Results revealed that the percentage of cMLSB, iMLSB, and MS phenotypes were 40%, 10% and 9% respectively. Overall, 41% isolates of S. aureus showed susceptibility to Erythromycin. Both iMLSB and cMLSB phenotypes were the most predominated among MRSA isolates. AgNPs was found to have strong antibacterial effect with MIC of 1μg/ml and partially synergistic activity with clindamycin towards S. aureus. Intraperitoneal administration of AgNPs was found to be moderately toxic.