Detection of Oxacillin (Methicillin)-resistant Staphylococcus aureus Isolated from a Tertiary-care Hospital, Georgetown, Guyana
Paul Cheddie *
Department of Medical Technology, Faculty of Health Sciences, University of Guyana, Turkeyen Campus, Georgetown, Guyana.
Drovashti Seepersaud
Department of Medical Technology, Faculty of Health Sciences, University of Guyana, Turkeyen Campus, Georgetown, Guyana.
Tereasia Ramlochan
Department of Medical Technology, Faculty of Health Sciences, University of Guyana, Turkeyen Campus, Georgetown, Guyana.
*Author to whom correspondence should be addressed.
Abstract
Background and Aim: Methicillin-resistant Staphylocccus aureus (MRSA) continues to be a major problem globally. Previous data had suggested that the prevalence of MRSA infections in the tertiary hospital setting was 51%. The aim of this study was to conduct a point prevalence survey of MRSA infections occurring at a tertiary-care hospital in Georgetown, Guyana, and to determine to what extent methicillin-resistance was occurring among Staphylococcus aureus isolates utilising the minimum inhibitory concentration (MIC) data.
Study Design: This study was based on a prospective, analytical design.
Place and Duration of Study: Microbiology department, Georgetown Public Hospital Corporation (GPHC), and Department of Medical Technology, University of Guyana, between May 2019 and July 2019.
Methodology: A total of 101 consecutive, non-repetitive, laboratory-identified MRSA and methicillin-susceptible Staphylococcus aureus (MSSA) isolates were tested using an oxacillin broth microdilution method.
Results: We found that 65.4% of Staphylococcus aureus were oxacillin (methicillin) resistant with a majority of the isolates being high level oxacillin resistant strains (i.e., MICs > 256 μg/ml) (84.85%). Most of the resistant isolates were collected from patients admitted to medical and surgical wards. Conclusion: Methicillin-resistance continues to be a major problem in the hospital setting and conventional techniques are unlikely to identify all of the potentially resistant isolates.
Keywords: Methicillin-resistant Staphylococcus aureus, MRSA, MSSA, broth microdilution, Guyana.