Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) presents a significant threat in healthcare settings due to its resistance to various antibiotics and its ability to form biofilms, which enhance its survival and persistence. Dental healthcare personnel (DHP) are at risk for MRSA colonization due to their frequent exposure to patients and contaminated surfaces. The study was planned to monitor the occurrence of MRSA nasal carriage among DHP, antibiogram analysis, the biofilm-forming capabilities of these isolates, and characterization of the nuc and mecA genes. Nasal swabs were collected from DHP, and 50 isolates were cultured for S. aureus using standard microbiological techniques. Methicillin resistance was confirmed using the cefoxitin disc diffusion method according to Clinical Laboratory Standard Institute (CLSI) guidelines 2023. Of the 50 isolates, 9 (18%) were MRSA, and PCR was employed to detect nuc and mecA genes. The Kirby-Bauer (KB) disc diffusion method determined the antimicrobial susceptibility profile of 9 MRSA isolates. All were resistant to cefoxitin and penicillin while varying degrees of resistance were observed for other antibiotics. Vancomycin and linezolid show universal effectiveness, with all isolates being susceptible, confirming their role as a critical treatment option for MRSA infections. All MRSA isolates carried the nuc gene, confirming S. aureus, and 7 (77.7%) carried the mecA gene, confirming methicillin resistance; the remaining may carry other mec gene variants. Seven MRSA isolates carrying the mecA gene underwent SCCmec typing (I-V). Conventional PCR was used to amplify SCCmec types with the help of specific primers. Of the 7 isolates, 5 were positive for all five SCCmec types (I, II, III, IV, V). Two isolates carried different types n=1 (I, II, IV, V), and the remaining carried three SCCmec types n=1 (I, II, IV). Biofilm formation was quantified using a crystal violet assay. Among the MRSA isolates, 6 (56%) demonstrated moderate to strong biofilm formation. The study reveals potentially biofilm-forming MRSA strains in the nasal carriage of DHP. The high prevalence of biofilm-forming MRSA among DHP underscores the need for stringent infection control practices. The mixed susceptibility to other antibiotics like Piperacillin/Tazobactam, Gentamicin, and Ciprofloxacin indicates that antibiotic stewardship programs must be tailored to the specific resistance profiles of MRSA in different settings. In conclusion, these findings underscore the importance of infection control measures and ongoing surveillance within dental healthcare settings to moderate the risk of MRSA transmission and associated infections.