Molecular Genotyping of Methicillin Resistant and Susceptible Staphylococcus Aureus by Coagulase Gene Polymorphism

ABSTRACT

Background: Methicillin-resistant Staphylococcus aureus (MRSA) which causes nosocomial infections is among the most important multi-resistant pathogens worldwide. Investigations of MRSA outbreaks in nosocomial settings often require strain-typing data to verify effectively that the isolates belong to the outbreak strain; and to discriminate similarity from unsimilarity strains. Quick and reliable typing methods are required to obtain information among MRSA isolates and to allow faster implementation of appropriate control measures. Objective: The aim of this study was to investigate genotyping of methicillin resistant and sensitive Staphylococcus aureus (MRSA and MSSA) in Khartoum Teaching Hospital; Sudan by using antibiotype and polymerase chain reaction-restriction fragment length polymorphism (PCRRFLP) of the coagulase gene. Methods: This is across sectional study. The samples were collected from clinical wound specimens in the wards of surgery; orthopaedic and burns at Khartoum Teaching Hospital; then processed; cultured and subsequently susceptibility test was performed using disc diffusion method. The MRSA strains were investigated by oxacillin 1[g disk diffusion method. PCR used to amplify a sequence of the coagulase (coa) gene; and the PCR products were analyzed by PCR-RFLP using Alu1 restriction enzyme. Result: Forty eight S. aureus strains were isolated and the number of MRSA identified was 9(18.75). All strains of MRSA and MSSA were sensitive to vancomycin; while multi-drug resistance was common among MRSA strains. PCR amplification products of coa gene were approximately at 500 bp (26/48); and 580 bp (22/48). By Alu1 restriction enzyme digestion of the PCR-amplified of coagulase gene; two distinct PCR-RFLP patterns exhibited; coaA and coaB and their fragments were approximately at 190; 310 bp and 190; 390 bp with percentages of 54.2(26/48) and 45.8(22/48) respectively. Conclusion: PCR-RFLP is considered an attractive tool for rapidly demonstrate the frequency of different patterns and discriminate the relatedness of isolates in different hospital wards