“Evaluation Of Several Phenotypic Methods Of Antibiotic Susceptibility Pattern For The Detection Of MRSA With Molecular Profiling RT-PCR With The Detection Of MecA Gene”

Abstract

INTRODUCTION:- Methicillin-resistant Staphylococcus aureus (MRSA) is a well-recognized public health problem throughout the world and community MRSA strains are now epidemic in India and others countries. The resistance rates of S. aureus infection and multidrug resistant strains are increasing, making the clinical anti-infective treatment and diagnosis more difficult.
 AIM:- To evaluate several phenotypic methods of the antibiotic susceptibility pattern for the detection of MRSA with Molecular Profiling Rt-PCR with the detection of MecA gene.
 MATERIALS AND METHODS:- The present study was a prospective observational study carried out at the Department of Microbiology, Santosh Medical College, Ghaziabad in a tertiary care hospital over a 12-month period from August 1, 2020 to July 31, 2021. Both IPD and OPD clinical sample comprised 385 clinical isolates as Staphylococcus aureus from various clinical specimens were included. Antibiotic susceptibility by the Kirby-Baure disc diffusion methods was performed according to the Clinical and Laboratory Standard Institute (CLSI) guidelines. Detection of MRSA by various methods like, Cefoxitin Disk diffusion Method, Oxacillin Disk diffusion method, E-Test method and detection of MecA gene by RT-PCR was carried out.
 RESULT:- In the present study out of 384 clinical samples, the majority of isolates from MRSA were found to be resistant to (E-Test) strip Oxacillin 114 (29.7%), followed by cefoxitin 113 (29.4%) and disc diffusion oxacillin 99 (25.8%). However, we observed a high incidence of resistance to other antibiotics such as Erythromycin 265 (69.0%), followed by Clotrimozole 228 (59.4%), Tetracyclin 144 (37.5), Vancomycin 102 (26.6%) and Refampicin 102 (26.6%). We also observed that Linezolid 354 (92.2%) followed by Teicoplanin 325 (84.6%), Gentamycin 272 (70.8%), Clindamycin 249 (64.8%) and Amoxyclave 281 (73.2%). In this study molecular RT-PCR test for the detection of mecA gene observed more in pus with 36 samples out of 113 followed by blood 17, urine 33, Sputum 05, pleural fluid 04, wound swab 16, Vaginal swab 06, CSF 01, Throat swab 2.
 CONCLUSION:- The gold standard assay for determining methicillin resistance is the PCR technique for detecting the mecA gene. But Because PCR is still time intensive and expensive, and it is not yet available in the 95% of routine clinical laboratories the phenotypic methods is still the choice where E-test is more reliable method than the disc diffusion method in detecting the drug resistance and can be utilised on a regular basis for better results.