Antimicrobial resistance : a case study on archived staphylococcus aureus isolates at the Jinja Referral Hospital

Abstract

Bacterial infections are leading global cause of mortality and morbidity in Uganda. The injudicious use of conventional antibiotics in treatment of these infections has led to increased antimicrobial resistance. Staphylococcus aureus is a leading cause of bacterial infections and its resistance to penicillin has been due to presence of MecA gene in its genome. The study sought to identify bacteria implicated in clinical samples, their antibiograms and screen for the presence of MecA gene among Staphylococcus aureus positive isolates. Different clinical specimens were cultured and analysed using standard microbiological methods. Biochemical tests were done on isolates that showed growth characteristics for Staphylococcus aureus, which included; Catalase and Coagulase tests to confirm its presence. Plates whose colonies were coagulase-positive were subjected to drug susceptibility test using Disc Kirby Method of drug diffusion and the zones of inhibition were noticed. A conventional PCR was run on all Staphylococcus isolates (n=41), to screen for the Mec A gene. The most prevalent bacteria isolated from clinical samples were Staphylococcus aureus 59 (3.5%). Highest resistance was against penicillin G 6/11 (54.6%), erythromycin 7/22 (31.8%), and tetracycline 5/22 (22.3%). Highest sensitivity was due to vancomycin 21/21 (100%), teicoplanin 21/22 (95.5%), clindamycin 20/21 (95.2%) and gentamycin 15/16 (93.8%). Out of the 41 Staphylococcal positive isolates, MecA gene positive isolates were 13 (32%). The use of alternative drugs to penicillin and tetracycline is advised while treating Staphylococcal infections such as vancomycin in the Jinja region. Information from this study may be used in future as a baseline for the follow-up to the susceptibility trend of various bacteria to the available drugs after laboratory confirmation.