Prevalence of Staphylococcus aureus methicillin-sensitive and methicillin-resistant nasal and pharyngeal colonization in outpatients in Lebanon

Abstract

Background There is an increasing concern about methicillin-resistant Staphylococcus aureus (MRSA) infections in the community. This study aimed to evaluate the rate of S aureus nasopharyngeal colonization in outpatients as the primary endpoint, and also to study the impact of several possible risk factors, including recent hospitalization, recent surgical procedures, and antibiotic intake.

Methods A total of 1,526 consecutive outpatients underwent surveillance cultures after completing a questionnaire. Isolated S aureus strains were tested for antibiotic susceptibility. The Pearson χ2 test was used for statistical analysis. The differences were considered to be statistically significant at a P value <.05.

Results Out of the 1,526 outpatients tested, 133 (8.7%) carried S aureus in the nose and/or throat. Only 2 of those cases were MRSA, and both were isolated from the nose. One hundred thirty-one patients had methicillin-sensitive S aureus, 13 with simultaneous carriage in the nose and throat. Among the risk factors, a relative working in health care, presence of an intravascular device, recent dental procedure, and health club use were significantly associated with an increased risk of S aureus colonization, with P values of .00, .02, .04, and .00, respectively, calculated by the χ2 test.

Conclusions The prevalence of MRSA is still low in our study population within the Lebanese community. The only significant risk factors playing a role in increasing the carriage of S aureus were related to health care exposure.