Phenotypic and Genotypic Detection of Biofilm Producing Methicillin Resistant Staphylococcus aureus (MRSA) Isolated from Human

Abstract

This study was aimed for phenotypic and genotypic detection of biofilm-producing Methicillin-resistant Staphylococcus aureus (MRSA) isolated from human. One hundred and fifty human nasal samples from different locations in Baghdad governorate, Iraq were collected during the period from October 2020 to April 2021. Samples were inoculated on mannitol salt agar (MSA) and incubated at 37°C for 24 hrs then, subcultured on blood agar. Detection of isolates was carried out according to colony characterization, Gram staining, conventional biochemical tests and analysis profile Vitek® 2, Bacterial resistance and MRSA was determined by disc diffusion. The biofilm synthesis was detected by Congo red agar method. The genotypic analysis of MRSA isolates using deoxyribonucleic acid (DNA) extraction to detect the 23srRNA, and mecA genes by polymerase chain reaction (PCR) assay. The MRSA was found in 18.6% (28/150) of human swabs, the biofilm positive MRSA of 28 of human isolates were 89.28%.The isolates showed high rate of multidrug resistance 82.14%, with high resistance to penicillin and methicillin (100%), azithromycin (85.71%), fusidic acid (75%) and oxacillin (71.42%). However, it was sensitive to: Bacitracin (100%), Norfloxacin (96.42%), Gentamycin and Clindamycin (85.71%), Vancomycin (71.42%). Genotypes identified by PCR showed that all isolate (100%) harboring 23srRNA and 76% harboring mecA genes. Our results revealed a correlation of mecA gene and biofilm synthesis in MRSA isolate.