Factors associated with severity in Klebsiella pneumoniae community-acquired pneumonia: A retrospective cohort study from South India

Klebsiella pneumoniae is increasingly recognized as a pathogen of concern causing community-acquired pneumonia (CAP) due to its association with diabetes, alcohol use, and antimicrobial resistance. However, data from India regarding severity in K. pneumoniae CAP is limited. The primary objective of this study was to determine the factors associated with severity in K. pneumoniae CAP. We conducted a retrospective cohort study of culture-confirmed K. pneumoniae CAP at a tertiary care hospital between January 2017 and December 2023. Eligible cases were defined as those with radiological evidence of CAP and culture positivity from respiratory or blood samples obtained within 48 hours of admission. Demographic, clinical, laboratory, radiological, microbiological, treatment, and outcome data were extracted. Factors associated with severity were identified using multivariable logistic regression. Of 277 culture-confirmed cases of K. pneumoniae from samples sent within 48 hours of admission, 105 fulfilled inclusion criteria. Of these, 32 patients (30.5%) had a severe disease. Patients with severe disease frequently reported alcohol use, presented with bacteraemia, shock, higher leukocyte counts, elevated urea, lower serum albumin, and greater antimicrobial resistance. On multivariable analysis, factors associated with severe disease were alcohol use (aOR 18.8, 95% CI 3.5–101), bacteraemia (aOR 11.8, 95% CI 1.8–77.5), ceftriaxone resistance (aOR 6.6, 95% CI 2.1–20.5), and higher leucocyte counts (aOR 1.15 per unit increase, 95% CI 1.05–1.26). K. pneumoniae isolates from patients with CAP are frequently resistant to ceftriaxone. Ceftriaxone resistance, along with alcohol use, bacteraemia, and high leucocyte count, was associated with severe disease.