Phenotypic and Genotypic Characterization of Methicillin Resistance in Staphylococci Isolated from an Egyptian University Hospital.

Methicillin-resistant in is a serious public health issue. It is mostly encoded by the gene. The gene is a new analog responsible for resistance to methicillin in some clinical isolates. This gene is still underestimated in Egypt. The aim of the current study was to detect genes in clinical isolates from a tertiary care university hospital in Egypt compared to the different phenotypic methods. A total of 118 () and 43 coagulase-negative (CoNS) were identified from various hospital-acquired infections. Methicillin resistance was identified genotypically using the PCR technique and phenotypically using the cefoxitin disc diffusion test, oxacillin broth microdilution and the VITEK2 system in all isolates. The gene was detected in 82.2% of and 95.3% of CoNS isolates, while all of the isolates tested negative for the gene. Interestingly, 30.2% of CoNS isolates showed the unique character of inducible oxacillin resistance, being -positive but oxacillin-susceptible (OS-CoNS). The dual use of genotypic and phenotypic methods is highly recommended to avoid missing any genetically divergent strains.