Session:

Infectious Disease Surveillance

Abstract No.:

41.038

Title:

Low Methicillin Resistant Staphylococcus aureus (MRSA) colonization among HIV positive patients attending an outpatient clinic in Sungai Buloh Hospital, Malaysia

Author(s):

S. F. A. Mohd Nawi¹, S. Kumar², A. Adnan¹, Z. Mohd Zain¹, C. Lee²; ¹Faculty of Medicine, Universiti Teknologi Mara (UiTM) Shah Alam, Medical Microbiology, Shah Alam, SELANGOR/MY, ²Hospital Sungai Buloh,, Department of Medicine, , Sungai Buloh, Selangor, SELANGOR/MY

Abstract:

Background: Methicillin Resistant Staphylococcus aureus (MRSA) is a multi-drug resistant bacterium which can cause a variety of conditions from mild to life-threatening skin and soft tissue infections. MRSA colonizers are prone to develop infections. The colonization rates in the general population vary from < 1% in Northern Europe to > 40% in Southern and Western Europe.  In the United States, HIV positive patients were found to have a 6-fold increase in MRSA colonization rates when compared with non-HIV infected patients. To date, there is no published data on MRSA screening among HIV patients in this country. The purpose of this study is to determine the rates of MRSA colonization among HIV positive patients in our population.
Methods: 130 HIV positive patients had swabs taken during an outpatient clinic visit in Sungai Buloh Hospital. The swabs were taken from four different sites (anterior nares, throat, axilla and skin) from each patient. Each of these swabs was streaked on Mannitol Salt Agar (MSA) and incubated overnight. S. aureus was identified was based on standard microbiological methods. The antibiotic susceptibility testing (AST) was performed and interpreted according to the Clinical Laboratory Standard Institute (CLSI) 2011 guidelines.
Results: A total of 520 swabs were collected from 130 patients.  69 swabs which was taken from 45 patients had S. aureus. 30 of these swabs were from anterior nares; 20, 12 and 7 swabs were from the throat, skin and axilla respectively. Anterior nare swabs picked up 66.7% (30/45) of the carriers. Throat swabs picked up an additional 20% (9/45). Skin and axillary swabs picked up another additional 13% (6/45) and 4% (2/45). There was only one S. aureus isolate which was found to be MRSA. It showed resistance to penicillin, oxacillin, erythromycin, clindamycin and trimethoprim-sulphamethoxazole.
Conclusion: While the Staphylococcus aureus carrier rate in this HIV positive population was 34.6% (45/130), the incidence of MRSA was only 2.2% (1/45). In this study, sampling from different sites per patient increased the yield of positive results. The most useful site was the anterior nares, however swabbing anterior nares alone would have missed 33.3% of the carriers.