Genetic Profiling of Methicillin-resistant Staphylococcus aureus in An African Hospital by Multiplex-PCR

Abstract

Objectives: Methicillin resistant Staphylococcus aureus (MRSA) nasal carriage often precedes infection. This work aims to genetically profile the MRSA carriage of resistant genes (mecA, blaZ and tetM) and certain virulence genes (nuc, pvl, spa and scn) obtained from human nasal cavity. Methods: Phenotypically confirmed Staphylococcus aureus were Screened for oxacillin resistance and assessed for β-lactamase production. Further confirmation of identity obtained by multiplex PCR of the 16SrRNA, mecA, tetM, pvl, nuc, spa and scn genes. DNA gel fingerprint analysis was carried out and the bands were clustered in a dendrogram. Results: The study analysed 81 Staphylococcus aureus isolates for Methicillin resistance out of which 38 (46.9%) were MRSA. The DNA extraction method was effective for all MRSA isolates evaluated. All phenotypic MRSA isolates (100%) were positive for the S. aureus specific 16SrRNA gene confirming that these isolates were S. aureus strains. The nuc gene was detected in 19/38 (50%) of the MRSA isolates, blaZ gene in 14/38 (36.8%) and tetM in 18/38 (47.4%). Conclusions: The need for improved vigilance to recognize MRSA strains cannot be overemphasized. If MRSA control is not tracked, these strains will increase exponentially. J Microbiol Infect Dis 2020; 10(3):144-153.