Methicillin Resistant Staphylococcus aureus nasal carriage and associated factors in a rural tertiary hospital in Eastern Uganda: A prospective cross-sectional study

Abstract

Background: Asymptomatic carriage of Methicillin-Resistant Staphylococcus aureus (MRSA) can predispose the host to a wide array of infections that would pose a challenge in the management of the cases in a current era encompassed with antibiotic resistance. To inform public health strategies, the study sought to describe MRSA nasal carriage frequencies and the associated factors concerning nasal carriage among patients attending Mbale Regional Referral Hospital (MRRH). Methods: Two hundred eighteen consented participants presenting to the hospital for medical care between January and April 2018 were recruited to participate in this study. Sampling was done on both anterior nares using a pre-moistened swab and then transported to the laboratory at Room temperature for the detection of MRSA. Culture was performed on blood agar and plates incubated at 37℃ for 24 hours. Identification of Staphylococcus aureus was done using conventional biochemical tests . MRSA was detected phenotypically using cefoxitin (30µg) as a surrogate test as per the Clinical Laboratory Standard Institute guidelines 2017 version. Patient demographic characteristics and the MRSA nasal carriage factors were collected using a pre-tested questionnaire. The collected raw data was entered into excel and later imported into STATA software for analysis. Results: Overall, Majority of the participants were in-patients (138, 63.3%) with the proportions of both females and males among the participants being 154/218 (70.6%) and 64/218 (29.3%) respectively. Mean age for both female and male participants was 40.16 (SD± 17.04) years respectively. Staphylococcus aureus nasal carriage rate among the participants was 22.9% (50/218), with 72% (36/50) of the harboured strains phenotypically expressing methicillin resistance. Colonization with Methicillin Resistant Staphylococcus aureus did not show any significant relationship with all the studied factors. Conclusion: There was a moderate Staphylococcus aureus nasal carriage among the participants in Mbale Regional Referral Hospital. We also observed a highly displayed phenotypic expression of methicillin resistance among the isolated Staphylococcus aureus strains. The studied factors indicated an independent influence on the rate of nasal carriage. For surveillance purposes to combat future outbreaks, there is a need to do a larger study with better power to better draw generalizable conclusions of carriage in the population.