Biomedicine

Abstract

Introduction and Aim: Staphylococcus species are important bacterial pathogens implicated in invasive infections. Staphylococcus aureus and coagulase negative staphylococci including Staphylococcus epidermidis have been considered as multi drug resistant and emergence of linezolid resistance in staphylococci has been reported. The molecular characterization of linezolid resistance in Staphylococcus epidermidis isolated from clinical specimens of blood culture was planned in this study by targeting cfr and optrA genes associated with linezolid resistance. Materials and Methods: A total of 120 clinical isolates of Staphylococcus epidermidis recovered from blood culture samples were tested for linezolid susceptibility by phenotypic methods including disk diffusion and minimum inhibitory concentration. Further, molecular characterization of linezolid resistance in phenotypically confirmed linezolid resistant Staphylococcus epidermidis was performed by detecting cfr and optrA genes by polymerase chain reaction. Results: Out of total 120 isolates of Staphylococcus epidermidis, 3.3% were found linezolid resistant by phenotypic methods. On molecular testing, cfr gene was detected in 2.5% of Staphylococcus epidermidis isolates. However, all the isolates were negative for optrA gene. Conclusion: The emergence of linezolid resistance in Staphylococcus epidermidis is a serious concern. The molecular characterization targeting cfr gene can serve as a rapid and reliable method for confirmation of linezolid resistance to guide antimicrobial treatment.