2017 Article - "Density of Upper Respiratory Colonization With Streptococcus pneumoniae and Its Role in the Diagnosis of Pneumococcal Pneumonia Among Children Aged <5 Years in the PERCH Study" (pdf, 692KB)
Summary: Previous studies suggested an association between upper airway pneumococcal colonization density and pneumococcal pneumonia, but data in children are limited. Using data from the Pneumonia Etiology Research for Child Health (PERCH) study, we assessed this potential association.
PERCH is a case-control study in 7 countries: Bangladesh, The Gambia, Kenya, Mali, South Africa, Thailand, and Zambia. Cases were children aged 1–59 months hospitalized with World Health Organization–defined severe or very severe pneumonia. Controls were randomly selected from the community. Microbiologically confirmed pneumococcal pneumonia (MCPP) was confirmed by detection of pneumococcus in a relevant normally sterile body fluid. Colonization density was calculated with quantitative polymerase chain reaction analysis of nasopharyngeal/oropharyngeal specimens.
Median colonization density among 56 cases with MCPP (MCPP cases; 17.28 ×106copies/mL) exceeded that of cases without MCPP (non-MCPP cases; 0.75 ×106) and controls (0.60 ×106) (each P < .001). The optimal density for discriminating MCPP cases from controls using the Youden index was >6.9 log10 copies/mL; overall, the sensitivity was 64% and the specificity 92%, with variable performance by site.
Pneumococcal colonization density >6.9 log10 copies/mL was strongly associated with MCPP and could be used to improve estimates of pneumococcal pneumonia prevalence in childhood pneumonia studies. Our findings do not support its use for individual diagnosis in a clinical setting.
Kit used: FTD Respiratory pathogens 33