Streptococcus Pneumoniae Colonization among Children in Galle, Sri Lanka: A Cross-Sectional Study

Background: Streptococcus pneumoniae, a Gram-positive bacterium that is found in the human respiratory tract, is the most common cause of bacterial pneumonia globally. Pneumococcal pneumonia can be effectively prevented by administering pneumococcal vaccines but pneumococcal vaccination is not provided through the public healthcare sector in Sri Lanka at present. This study will serve as evidence instructing future decisions regarding the utility of vaccination.

Methods: A cross-sectional survey was conducted in Galle, Sri Lanka from July to September 2019 . Eleven Medical Officer of Health (MOH) clinics, which provide routine vaccinations to infants and children through the public health sector, were selected as the study setting. The parents of consecutive children ≤5 years of age were approached for consent. A nasopharyngeal sample was collected from each enrolled child and socio-demographic and clinical data were obtained by interviewing the parents. Routine microbiological testing was conducted to confirm the presence of S. pneumoniae isolates. Antibiotic susceptibility testing was performed on confirmed isolates using Kirby-Bauer disc diffusion. Sociodemographic and clinical characteristics associated with S. pneumoniae colonization were assessed using bivariable and multivariable logistic regression in R.

Results: Among 123 enrolled patients, 26 (21.1%) were found to be colonized with S. pneumoniae. Higher risk of S. pneumoniae colonization was found to be associated with living with other children <5 years (Unadjusted OR=4.58, 95%CI: 1.69-12.83); Adjusted OR=3.99, 95%CI: 1.19-13.39) in both bivariate and multivariate analysis. With age >2 years was found to be associated with lower risk of being infected (Unadjusted OR=0.19, 95%CI: 0.02-0.84) in bivariate analysis, and drinking boiled water was found protective to the carriage than no treatment (Adjusted OR=0.11, 95%CI: 0.02-0.65) in multivariate analysis. For antibiotic resistance, the non-susceptible prevalence was 94.4% to oxacillin/penicillin, 72.2% to erythromycin, and 44.4% to clindamycin. All isolates were susceptible to levofloxacin.

Discussion: This is the first report of S. pneumoniae colonization prevalence among children in Southern Province, Sri Lanka. One-fifth of children were found to be colonized with S. pneumoniae, and oxacillin non-susceptibility prevalence was high. Further characterization must be performed to identify serotypes of colonizing strains and to correlate with serotypes present in available vaccines. Our results provide evidence regarding burden of pneumococcal colonization in Sri Lanka, and may help guide pneumococcal vaccine decisions in Sri Lanka.