Prevalence and molecular characterization of MSSA and MRSA among UniSZA undergraduate students in Besut, Terengganu

Abstract

Background: Methicillin-resistant Staphylococcus aureus (MRSA) is bacteria that resistant to multiple antibiotics, making MRSA infection difficult to treat. Previous studies had indicated that livestock associated MRSA (LA-MRSA) is presence in livestock and able to transmit to human that have close contacts with animals. In the past, LA-MRSA is always related with the presence of tetracycline resistance and lack of immune evasion cluster (IEC) while MRSA strain originated from human posses IEC but without tetracycline resistant genes. LA-MRSAs with IEC genes may able to infect human more efficiently as the human innate immunity cannot respond to the LA-MRSA invasion. This study was carried out to study the prevalence of methicillin-susceptible S. aureus (MSSA) and MRSA among UniSZA students that have previous exposure to animal as well to detect the presence of IEC and tetracycline resistance genes in the MSSA isolates. Methods and materials: A total of 400 swab samples (200 oral and nasal respectively) were collect from 200 students that belongs to 5 different undergraduate courses in UniSZA. Isolation of S. aureus was done using phenotypic identification methods, followed by detection of nuc and mecA genes using PCR. Isolates that been identified as MSSA were later tested using PCR to determine the presence of IEC and tetracycline resistance genes. The antibiotic susceptibility pattern of MSSA isolates were also been investigated. Results: 87 isolates are confirmed to contain nuc gene by using PCR and no mecA gene were detected, indicating the absent of MRSA from students. MSSA isolates show resistances towards various antibiotics (chlorampenicol, oxacillin, amikacin, tetracycline and cephalothin), suggesting that the emergence of antimicrobial resistance MSSA among the students. 3.1% (2/65) isolates shown the presence of IEC type E while 43 (66.2%; 43/65) MSSA contain only sak genes. No tetracyclines resistance genes were detected. Conclusion: As the MSSA isolated from these students may already spread among the animals, antibiotic awareness, careful monitoring and responsible usage of antibiotics must be carried out to avoid the emergence of multiple drugs resistant MSSA to be transmitted between species.