Serotype epidemiology and antibiotic resistance of pneumococcal isolates colonizing infants in Botswana (2016-2019).

BACKGROUND: In 2012, Botswana introduced 13-valent pneumococcal conjugate vaccine (PCV-13) to its childhood immunization program in a 3+0 schedule, achieving coverage rates of above 90% by 2014. In other settings, PCV introduction has been followed by an increase in carriage or disease caused by non-vaccine serotypes, including some serotypes with a high prevalence of antibiotic resistance. METHODS: We characterized the serotype epidemiology and antibiotic resistance of pneumococcal isolates cultured from nasopharyngeal samples collected from infants (≤12 months) in southeastern Botswana between 2016 and 2019. Capsular serotyping was performed using the Quellung reaction. E-tests were used to determine minimum inhibitory concentrations for common antibiotics. RESULTS: We cultured 264 pneumococcal isolates from samples collected from 150 infants. At the time of sample collection, 81% of infants had received at least one dose of PCV-13 and 53% had completed the three-dose series. PCV-13 serotypes accounted for 27% of isolates, with the most prevalent vaccine serotypes being 19F (n = 20, 8%), 19A (n = 16, 6%), and 6A (n = 10, 4%). The most frequently identified non-vaccine serotypes were 23B (n = 29, 11%), 21 (n = 12, 5%), and 16F (n = 11, 4%). Only three (1%) pneumococcal isolates were resistant to amoxicillin; however, we observed an increasing prevalence of penicillin resistance using the meningitis breakpoint (2016: 41%, 2019: 71%; Cochran-Armitage test for trend, p = 0.0003) and non-susceptibility to trimethoprim-sulfamethoxazole (2016: 55%, 2019: 79%; p = 0.04). Three (1%) isolates were multi-drug resistant. CONCLUSIONS: PCV-13 serotypes accounted for a substantial proportion of isolates colonizing infants in Botswana during a four-year period starting four years after vaccine introduction. A low prevalence of amoxicillin resistance supports its continued use as the first-line agent for non-meningeal pneumococcal infections. The observed increase in penicillin resistance at the meningitis breakpoint and the low prevalence of resistance to ceftriaxone supports use of third-generation cephalosporins for empirical treatment of suspected bacterial meningitis.

Treatment Failures and Excess Mortality Among HIV-Exposed, Uninfected Children With Pneumonia.

BACKGROUND: Human immunodeficiency virus (HIV)-exposed, uninfected (HIV-EU) children are at increased risk of infectious illnesses and mortality compared with children of HIV-negative mothers (HIV-unexposed). However, treatment outcomes for lower respiratory tract infections among HIV-EU children remain poorly defined. METHODS: We conducted a hospital-based, prospective cohort study of N = 238 children aged 1-23 months with pneumonia, defined by the World Health Organization. Children were recruited within 6 hours of presentation to a tertiary hospital in Botswana. The primary outcome--treatment failure at 48 hours--was assessed by an investigator blinded to HIV exposure status. RESULTS: Median age was 6.0 months; 55% were male. One hundred fifty-three (64%) children were HIV-unexposed, 64 (27%) were HIV-EU, and 20 (8%) were HIV-infected; the HIV exposure status of 1 child could not be established. Treatment failure at 48 hours occurred in 79 (33%) children, including in 36 (24%) HIV-unexposed, 30 (47%) HIV-EU, and 12 (60%) HIV-infected children. In multivariable analyses, HIV-EU children were more likely to fail treatment at 48 hours (risk ratio [RR]: 1.83, 95% confidence interval [CI]: 1.27-2.64, P = .001) and had higher in-hospital mortality (RR: 4.31, 95% CI: 1.44-12.87, P = .01) than HIV-unexposed children. Differences in outcomes by HIV exposure status were observed only among children under 6 months of age. HIV-EU children more frequently received treatment with a third-generation cephalosporin, but this did not reduce the risk of treatment failure in this group. CONCLUSIONS: HIV-EU children with pneumonia have higher rates of treatment failure and in-hospital mortality than HIV-unexposed children during the first 6 months of life. Treatment with a third-generation cephalosporins did not improve outcomes among HIV-EU children.