Molecular detection of mecA gene in methicillin resistant Staphylococcus aureus isolated from clinical specimens: A descriptive case series study from Pakistan

Methicillin resistant Staphylococcus aureus (MRSA) is one of the major public health issues. Its incidence rate is increasing day by day and creating problems in its treatment due to its increased rate of resistivity to available antibiotics. The reason for the methicillin resistance is the mecA gene, located in the SCCmec region of the chromosome of S. aureus. The modified form of penicillin-binding protein is produced in the presence of the mecA gene which is known as PB2a. This PB2a has a low affinity for the β-lactam antibiotics which have an inhibitory action on the synthesis of the cell wall of bacteria.Methods: 58 MRSA isolates are used in the current study for the detection of the mecA gene through PCR. The antibiotic resistance pattern of MRSA isolates is also checked against 18 antibiotics using the disc diffusion method. Demographic data is also evaluated for determining the prevalence of MRSA based on specimens, gender, age, and area.Results: In the current study, the incidence rate of MRSA in the pus fluid sample was high (36.2%) and lowest in body fluid, ear swab, and HVS (1.72%). The most affected age group found in males and females is 21-41 years and the least affected is 61-80 years. Area-wise distribution of MRSA reveals that Lahore (27.58%) has a high prevalence as compared to other cities. The MRSA was most susceptible to teicoplanin (100%) than to vancomycin (93.10%) and linezolid (81.03%). The study done on the basis of mecA gene detection showed that out of 58 strains 63.34% gave positive results while 39.76% gave negative results. The frequency of the mecA gene in males was 61.11% and in females, it was 59.09%. Overall, the incidence rate of MRSA was found higher in males as compared to females and it was found most susceptible to teicoplanin which is the drug of choice along with vancomycin and linezolid for the treatment of MRSA infections.