Investigating the Genetics and Antibiotic Resistance of Methicillin ResistantStaphylococcus aureusin Biological Samples from Hospitalized Patients
Abstract
Background
Staphylococcus aureusis a gram-positive bacterium that can cause various diseases and infections. Penicillin and methicillin are examples of β-lactam antibiotics, the first line of defense againstStaphylococcus aureusinfections. Methicillin-ResistantStaphylococcus 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 themecAgene, which produces a penicillin-binding protein (PBP2a) with a low affinity for β-lactam antibiotics.
Methods
This 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, andmecAgene-specific primers were used to detect the gene in the samples.
Results
Out of 4383 samples, 848 (21.00%) samples have growth, and 190(22.4%) were Staphylococcus aureus. AmongStaphylococcus aureus52 (27.36%) were Methicillin resistantStaphylococcus 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 themecAgene, while 3.85% showed the absence of themecAgene.
Conclusions
The frequency of MRSA infections in HA-MRSA was comparatively high, with a greater abundance of themecAgene that confers the resistance. Regular surveillance of HA-MRSA and genetic profiling of the mecA gene are essential for reducing MRSA infection.
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