Prevalence of Methicillin Resistant and Virulence Determinants in Clinical Isolates of Staphylococcus aureus

Manjunath Chavadi1, Rahul Narasanna1, Ashajyothi Chavan1, Ajay Kumar Oli2, Chandrakanth Kelmani. R1, *
1 Department of P.G. Studies and Research in Biotechnology, Gulbarga University, Gulbarga, Karnataka, India
2 SDM- Biomedical Research Center, SDM College of Medical Sciences and Hospital, Manjushree Nagar, Sattur, Dharwad, Karnataka, India

© 2018 Chavadi et al.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at the Department of Biotechnology, Gulbarga University, Gulbarga 585106, Karnataka, India; Tel: 9449439340; E-mail:



Methicillin-resistant Staphylococcus aureus (MRSA) is the major threat that is a result of the uncontrolled use of antibiotics causing a huge loss in health, so understanding their prevalence is necessary as a public health measure.


The aim of this study was to determine the prevalence of methicillin-resistant MRSA and virulence determinant among associated S. aureus from the clinical samples obtained from various hospital and health care centers of the Gulbarga region in India.

Materials and Methods:

All the collected samples were subjected for the screening of S. aureus and were further characterized by conventional and molecular methods including their antibiotic profiling. Further, the response of methicillin antibiotic on cell morphology was studied using scanning electron microscopy.


A total 126 S. aureus was isolated from the clinical samples which showed, 100% resistant to penicillin, 55.5% to oxacillin, 75.3% to ampicillin, 70.6% to streptomycin, 66.6% to gentamicin, 8.7% to vancomycin and 6.3% to teicoplanin. The selected MRSA strains were found to possess mecA (gene coding for penicillin-binding protein 2A) and femA (factor essential for methicillin resistance) genetic determinants in their genome with virulence determinants such as Coagulase (coa) and the X region of the protein A (spa) gene. Further, the methicillin response in resistant S. aureus showed to be enlarged and malformed on cell morphology.


The molecular typing of clinical isolates of S. aureus in this study was highly virulent and also resistant to methicillin; this will assist health professionals to control, exploration of alternative medicines and new approaches to combat Staphylococcal infections more efficiently by using targeted therapy.

Keywords: Staphylococcus aureus, Methicillin-resistant Staphylococcus aureus, MecA, FemA, Coagulase, Streptomycin.