HIV and influenza infection are associated with increased blood pneumococcal load : a prospective, hospital-based observational study in South Africa, 2009–2011

Abstract

BACKGROUND : Increased pneumococcal loads are associated with severe outcomes. We determined the prevalence of pneumococcal DNA in blood specimens from patients hospitalized with acute lower respiratory tract infection and identified factors associated with invasive pneumococcal pneumonia, bacterial loads, and death. METHODS : A total of 8523 patients were enrolled as part of prospective hospital-based surveillance. Blood was collected for quantitative pneumococcal (lytA) detection, and nasopharyngeal specimens were collected for detection of influenza virus and other respiratory viruses by real-time polymerase chain reaction. RESULTS : Of 6396 cases (75%) with lytA results, 422 (7%) were positive for pneumococcal DNA. The prevalences of human immunodeficiency virus (HIV) and influenza virus were 51% (2965/5855) and 8% (485/6358), respectively. On multivariable analysis, HIV infection (adjusted odds ratio [aOR], 2.4; 95% confidence interval [CI], 1.6–3.6), influenza virus coinfection (aOR, 1.4; 95% CI, 1.2–2.1), oxygen therapy during admission (aOR, 1.6; 95% CI, 1.1– 2.3) and in-hospital death (aOR, 2.1; 95% CI, 1.1–4.0) were significantly associated with increased pneumococcal load. Among lytA-positive patients, after adjustment for length of hospitalization, duration of symptoms, and oxygen therapy during admission, pneumococcal loads ≥10,000 DNA copies/mL (aOR, 3.6; 95% CI, 1.8–7.2) were associated with increased risk of death. CONCLUSIONS : HIV and influenza virus infections were associated with elevated pneumococcal loads, which, in turn, were associated with increased risk of death.