Evaluation of various staphylococcal cassette chromosome mec (SCCmec) types in Staphylococcus epidermidis invasive strains from hospitalised patients in Iran

Abstract

Staphylococcus epidermidis is known to be a major cause of nosocomial infections particularly in catheter-associated bacteraemia, prosthetic valve endocarditis (PVE) and immunocompromised patients in different health care units. The emergence of multidrug-resistant strains, especially to beta-lactam antibiotics such as methicillin, has increased the mortality due to S. epidermidis. A kind of low affinity penicillin-binding protein (PBP2alpha), which is encoded by the mecA gene that is located in the staphylococcal cassette chromosome mec (SCCmec), mediates the resistance to methicillin. The aim of this study was to investigate the prevalence of SCCmec types and evaluate the antibiotic profile assay in invasive strains isolated from clinical samples. The study focused on invasive strains, determining the antimicrobial resistance profile, designing new primers for detection of the mecA gene and SCCmec typing with the multiplex PCR method. By using the PCR molecular test, 87.1 of all isolates were found to be positive for the mecA gene. In SCCmec typing, different types (I-V) were identified, in which SCCmec type I was detected in 3 isolates, SCCmec type II in 5 isolates, SCCmec type III in 22 isolates, SCCmec type IV in 27 isolates and SCCmec type V was distinguished in 4 isolates. Since coagulase-negative staphylococci are reported as a major cause of hospital infections, molecular typing methods like SCCmec typing would be a helpful method to control and prevent bacterial infections.