Prevalence of Staphylococcus aureus Nasal Carriage in Human Immunodeficiency Virus–Infected and Uninfected Children in Botswana: Prevalence and Risk Factors

Abstract

Abstract<i>Staphylococcus aureus</i> is an important cause of morbidity and mortality in children in sub-Saharan Africa (SSA). A major risk factor for staphylococcal infection is <i>S. aureus</i> colonization of the anterior nares. We sought to define risk factors for <i>S. aureus</i> carriage and characterize antimicrobial resistance patterns in children in Botswana. A cross-sectional study was conducted at two clinical sites in southern Botswana. Patients under 18 years of age underwent two nasal swabs and brief interviews, 4 weeks apart. Standard microbiological techniques were used. For persistent carriers, <i>S. aureus</i> was isolated from swabs at both time points, and for intermittent carriers, <i>S. aureus</i> was isolated from only one swab. Poisson regression with robust variance estimator was used to compare prevalence of carriage and the resistance phenotypes. Among 56 enrollees, prevalence of <i>S. aureus</i> colonization was 55% (<i>N</i> = 31), of whom 42% (<i>N</i> = 13) were persistent carriers. Of human immunodeficiency virus-infected children, 64% (<i>N</i> = 9) were carriers. Risk factors for nasal carriage included a history of tuberculosis (prevalence ratio [PR] = 1.60; 95% confidence interval [CI] = 1.02, 2.51; <i>P</i> = 0.040) and closer proximity to health care (PR = 0.89; 95% CI = 0.80, 0.99; <i>P</i> = 0.048). Prior pneumonia was more common among persistent rather than intermittent carriers (PR = 2.64; 95% CI = 1.64, 4.23; <i>P</i> < 0.001). Methicillin-resistant <i>S. aureus</i> (MRSA) prevalence was 13%. Of isolates tested, 16% were resistant to three or more drugs (<i>N</i> = 7/44). In summary, children in southern Botswana are frequently colonized with <i>S. aureus</i>. Antibiotic resistance, especially MRSA, is also widespread. Antibiotic recommendations for treatment of staphylococcal infections in SSA should take cognizance of these resistance patterns.