Aetiological Spectrum and Predictors of Mortality in Hospitalised Adults with Community-Acquired Pneumonia: A Cross-Sectional Observational Study at a Tertiary Care Hospital

Abstract

Background: Pneumonia is one of the major causes of morbidity and mortality due to infection worldwide and is known as community-acquired pneumonia (CAP). The aetiological spectrum of CAP in Indian tertiary care hospitals is different from Western countries, Klebsiella pneumoniae was predominant and high percentage of antibiotic-resistant pathogens. Empirical antibiotic guidance is dependent upon knowledge of local microbiology and mortality predictors.

Methods: This was a cross sectional observational study involving 250 hospitalised adults with CAP (IDSA/ATS 2019 criteria) at a tertiary care hospital in 12 months. Comprehensive microbiological sampling, CURB-65 and PSI scoring, treatment outcome documentation, and multivariable mortality analysis were performed. Results: A causative pathogen was identified in 47.2% of cases. Streptococcus pneumoniae was most common (22.0%), followed by Klebsiella pneumoniae (14.0%), atypicals (8.0%), and viral co-infection (11.0%). Severe CAP (CURB-65 ≥3) was present in 22.4%; ICU admission in 18.0%; 30-day in-hospital mortality 9.2%. Independent mortality predictors included septic shock (aOR 5.6), CURB-65 ≥3 (aOR 4.5), inappropriate empirical antibiotic therapy (aOR 2.7), and diabetes (aOR 1.8). Conclusion: The CAP pathogen spectrum in this Indian tertiary care hospital combines classical pneumococcal disease with significant Gram-negative and atypical pathogen contribution. Inappropriate empirical therapy is a major modifiable mortality predictor. Local antibiogram-guided empirical protocols and early severity stratification by CURB-65 are essential for improving outcomes.