Keywords
aureus
MRSA
AST
mecA gene
How to Cite
Abstract
B Background:
Staphylococcus aureus, a Gram-positive, round shaped bacterium is normal flora of skin and upper part of respiratory system and causative agent of food poising, folliculitis, endocarditis, osteomyelitis, arthritis, pneumonia, and skin infection. Methicillin introduced in 1959 was used against diseases caused by S. aureus which has resistant against penicillin. The resistance towards methicillin is conciliated by gene mecA that codes penicillin-binding protein 2a (PBP 2a) which leads to resistance against all beta-lactam containing antibiotics namely methicillin and oxacillin.
Materials & Methods
A total 100 specimens were collected from the patient who visited Allied hospital (n=35), General hospital Ghulam Mohammadabad (n=35) and Social security hospital Faisalabad (n=30). Samples were cultured and Gram stained. All the Gram-positive bacteria were cultured on mannitol salt agar to obtain pure colonies. Antimicrobial susceptibility testing was performed for the screening of methicillin resistant S. aureus by using Kirby Bauer disk diffusion method. After obtain required organism which was methicillin resistance S. aureus, Polymerase chain reaction was done for mecA gene that is a methicillin resistant gene. DNA was extracted for molecular studies and gel electrophoresis was performed for all positive isolates individually.
Results:
A total of 38 samples out 100 were marked positive for presence of S. aureus. Highest prevalence of S. aureus was recorded in samples collected from Allied Hospital (16/35; 45.71%) followed by General Hospital Ghulam Muhammadabad (13/35; 37.71%) while samples from Social Security Hospital (n = 09/30; 30%) showed least prevalence. All the isolates (n = 38) were tested for antibiotic susceptibility pattern. The readings were compared with the CLSI guidelines and highest resistance percentage was calculated for penicillin G (100%) while highest susceptibility percentage was calculated for chloramphenicol (60.53%). Prevalence of MRSA isolates was calculated by analyzing the susceptibility of the isolates against cefoxitin (30 μg). 31 out of 38 isolates (81.58%) were marked to be methicillin resistant S. aureus. All MRSA isolates were tested for the occurrence of mecA gene by PCR and gel electrophoresis. A total of 19 isolates (61.29.5%) were marked positive for mecA gene.
CONCLUSION
The on the basis of finding of current study, S. aureus is one of the most prevalent pathogen in hospital sitting equipped with the wide range of virulence factors. As S. aureus is able to cause life threatening infections, the presence of S. aureus in clinical samples followed by the prevalence of mecA gene in isolates has been a serious threat to both healthcare worker and public health.