The impact of HIV on Streptococcus pneumoniae bacteraemia in a South African population.

OBJECTIVES: To determine the impact of HIV infection on Streptococcus pneumoniae bacteraemia in adults and children by analysing the prevalence and clinical features of such diseases and determining the prevalent serotypes/serogroups and susceptibility patterns of isolates.
DESIGN: Patients were identified prospectively from January to October 1996.
SETTING: Chris Hani Baragwanath Hospital, Soweto, a tertiary referral hospital treating adults and children, in an urban district near Johannesburg, South Africa. PATIENTS AND METHODS: All patients with S. pneumoniae isolated from blood culture by the Microbiology Department, Chris Hani Baragwanath Hospital were studied. Clinical and microbiological features were recorded.
RESULTS: A total of 178 patients with S. pneumoniae were investigated as part of the study; 49 were aged < 13 years. HIV seroinfection was present in 25 (51%) children and 58 (45%) adults. The incidence of S. pneumoniae bacteraemia was 36.9-fold increased in HIV-seropositive children and 8.2-fold increased in HIV-seropositive adults compared with HIV-seronegative individuals. Both adult and paediatric HIV-seropositive patients with S. pneumoniae bacteraemia were significantly younger than HIV-seronegative patients. Pneumonia was a significantly more common presentation in HIV-seropositive children, otherwise the spectrum of disease and outcome were similar in HIV-seronegative and positive groups. Serotype 1 S. pneumoniae isolates were significantly less common in HIV-infected individuals (both adults and children). Resistance to penicillin was increased in S. pneumoniae isolates from HIV-infected patients (significant in adults). Patients with penicillin-resistant isolates did not have a poorer outcome. The potential coverage of serotypes/serogroups included in the proposed nine-valent conjugate pneumococcal vaccine was 88% in HIV-seronegative children and 83% in HIV-seropositive children. The potential coverage of the currently available 23-valent pneumococcal vaccine for adults was 98.2 and 100)% for HIV-infected and HIV-uninfected adults, respectively.
CONCLUSION: The burden of bacteraemia due to S. pneumoniae in HIV-seropositive individuals admitted to our hospital is considerable. Differences in the S. pneumoniae serotypes/serogroups in HIV-infected patients have been demonstrated with resultant differences in antibiotic susceptibility patterns. Excellent potential for vaccine coverage was demonstrated for both HIV-seronegative and HIV-seropositive individuals. Further studies are necessary to test the clinical efficacy of pneumococcal vaccination of HIV-seropositive adults and children as a potential preventative measure against this prevalent disease.