Prevalence of methicillin-resistant Staphylococcus aureus nasal carriage among hospitalised patients with tuberculosis in rural KwaZulu-Natal

Abstract

Background. There is little information regarding the presence and characteristics of methicillin-resistant Staphylococcus aureus (MRSA), an important nosocomial pathogen, in rural African hospitals.
Objectives. To determine the prevalence of MRSA colonisation in patients admitted to a rural hospital with tuberculosis (TB) in an endemic HIV area and to describe transmission dynamics and resistance patterns among MRSA isolates.
Methods. A prospective prevalence survey in the adult TB wards of the Church of Scotland Hospital, a provincial government district hospital in Tugela Ferry, KwaZulu-Natal. Patients were eligible if over the age of 15 and admitted to the TB wards between 15 November and 15 December 2008. Nasal swabs were cultured within 24 hours of admission and repeated at hospital-day 14 or upon discharge. Susceptibility testing was performed with standard disk diffusion. Demographic and clinical information was extracted from medical charts.
Results. Of 52 patients with an admission nasal swab, 11 (21%) were positive for MRSA. An additional 4 (10%) of patients with negative admission swabs were positive for MRSA on repeat testing. MRSA carriage on admission was more common among patients with previous hospitalisation, among HIV-infected patients was significantly assciated with lower CD4 counts (p=0.03). All MRSA isolates were resistant to cotrimoxazole, and 74% were resistant to ≥5 classes of antibiotics; all retained susceptibility to vancomycin.
Conclusions. A high prevalence of multidrug-resistant MRSA nasal carriage was found. Studies are needed to validate nosocomial acquisition and to evaluate the impact of MRSA on morbidity and mortality among TB patients in similar settings.