NASOPHARYNGEAL PNEUMOCOCCAL COLONIZATION AMONG KENYAN CHILDREN - ANTIBIOTIC-RESISTANCE, STRAIN TYPES AND ASSOCIATIONS WITH HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1 INFECTION

Objectives. To compare pneumococcal nasopharyngeal colonization rates among HIV-1-infected children with those of uninfected children born t o seropositive mothers and those of seronegative controls. To determin e the predominant serotypes and antimicrobial susceptibility among pne umococcal isolates in Kenya. Methods. Nasopharyngeal pneumococcal colo nization was examined in 207 children recruited from the Perinatal HIV -1 Transmission Study conducted in Nairobi, Kenya. Colonization was co mpared among HIV-1-infected children, uninfected children born to sero positive mothers and control seronegative children. Isolates were sero typed and tested for antibiotic susceptibility to penicillin, tetracyc line, erythromycin, chloramphenicol, clindamycin and rifampin. Results . Colonization was higher among HIV-1-infected and uninfected children than among controls only when associated with respiratory illnesses ( 86% of 7 and 60% of 20 vs. 29% of 31, P = 0.004). No differences were observed when children were asymptomatic (20% of 35, 35% of 94 and 22% of 101). Intermediate penicillin resistance was found in 60% of 94 is olates, 28% were resistant to tetracycline and all isolates were susce ptible to the other antibiotics tested. Sixteen serotypes were identif ied, with 13, 15, 14, 6B and 19F comprising 73% of isolates. Serotype 13 was found in 31% of colonized children. This serotype and 2 others isolated are not found in the current 23-valent polysaccharide vaccine . Overall 41% of colonized children harbored nonvaccine strains. Concl usions. Although nasopharyngeal pneumococcal colonization was high amo ng children with respiratory illness born to HIV-1-seropositive mother s, increased asymptomatic colonization did not explain the increased r isk of invasive pneumococcal disease associated with HIV-1 infection. Intermediate penicillin resistance was common but high level penicilli n and multiple antibiotic resistance were not seen. The prevalence of the unique strains circulating in this region will need to be consider ed in the design of effective pneumococcal vaccines for use in East Af rica.