Investigating the Genetics and Antibiotic Resistance of Methicillin Resistant Staphylococcus aureus in Biological Samples from Hospitalized Patients

BackgroundStaphylococcus aureus is a gram-positive bacterium that can cause various diseases and infections. Penicillin and methicillin are examples of {beta}-lactam antibiotics, the first line of defense against Staphylococcus aureus infections. Methicillin-Resistant Staphylococcus aureus (MRSA) is still one of the leading causes of hospital-acquired infections associated with morbidity, mortality, and cost. MRSA can be hospital-acquired (HA-MRSA) or community-associated (CA-MRSA) infections. The main objective of this study is to screen MRSA among HA-MRSA to determine the prevalence of antibiotic susceptibility patterns of MRSA among patients. Furthermore, we identify the mecA gene, which produces a penicillin-binding protein (PBP2a) with a low affinity for {beta}-lactam antibiotics. MethodsThis study was done on the patients of Kathmandu Model Hospital, Nepal, and the samples were processed at the Microbiology laboratory of Kathmandu Model Hospital. Data analyses were done from Microsoft Excel and GraphPad Prism. DNA extraction was done from the classical CTAB method with minor modifications, and mecA gene-specific primers were used to detect the gene in the samples. ResultsOut of 4383 samples, 848 (21.00%) samples have growth, and 190(22.4%) were Staphylococcus aureus. Among Staphylococcus aureus 52 (27.36%) were Methicillin resistant Staphylococcus aures. Antibiotic susceptibility tests were done to characterize MRSA isolates. Most of the isolates were resistant to Amikacin (69.25%), followed by Ampicillin (53.8%), Chloramphenicol (78.84%), Cotrimoxazole (53.8%), Gentamycin (67.3%), Ofloxacin (15.39%), Erythromycin (71.15%) Vancomycin and Teicoplanin (3.84%). In our study, 50 (96.15%) out of 52 MRSA showed the mecA gene, while 3.85% showed the absence of the mecA gene. ConclusionsThe frequency of MRSA infections in HA-MRSA was comparatively high, with a greater abundance of the mecA gene that confers the resistance. Regular surveillance of HA-MRSA and genetic profiling of the mecA gene are essential for reducing MRSA infection.