Community-acquired Pneumonia in Bangladeshi Children Under Five: Pathogen Prevalence, Resistance Trends, and Diagnostic Biomarkers

BACKGROUND: Community-acquired pneumonia (CAP) is a leading cause of childhood mortality, with diverse etiologies. This study aimed to generate region-specific data to inform treatment and vaccination strategies for childhood CAP. METHODS: We enrolled 226 CAP cases and 201 controls (<5 years) at Dhaka Medical College & Hospital (March 2022-April 2023) in Dhaka, Bangladesh. Blood and nasopharyngeal swabs were collected for pathogen detection. Bacterial isolates were tested for antibiotic susceptibility, pneumococcal isolates were serotyped, and inflammatory markers (C-reactive protein, procalcitonin) were measured. RESULTS: No bacteremic cases of CAP were identified. Streptococcus pneumoniae [odds ratio (OR) = 2.26, 95% confidence interval (CI): 1.5-3.4], respiratory syncytial virus (OR = 6.16, 95% CI: 2.54-14.9), SARS-CoV-2, and influenza A/B were significantly associated with CAP, with SARS-CoV-2 and influenza A/B detected only in cases. Co-identification of pathogenic bacteria and viruses occurred in 14% (33/226) of cases. Over 90% of pneumococcal isolates were non-pneumococcal conjugate vaccine-10 serotypes, and serotype 19A was predominant (19%, 19/101 in cases and 6%, 3/53 in controls). Multidrug resistance was frequent in S. pneumoniae (40%, 71/178) and Haemophilus influenzae (38%, 20/52); 86% of pneumococci were macrolide nonsusceptible. Among Staphylococcus aureus , 76% (31/41) were methicillin-resistant. C-reactive protein and procalcitonin were elevated in severe CAP cases; however, no definitive cutoff threshold distinguished bacterial from viral causes. CONCLUSIONS: Our findings highlight the current epidemiology of childhood CAP in Dhaka, Bangladesh, identifying high antimicrobial resistance and predominance of non-pneumococcal conjugate vaccine-10 serotypes. These results underscore the need for continued pneumococcal surveillance to guide vaccine and treatment strategies and strengthened approaches for addressing antimicrobial resistance.