Bacterial etiology and risk factors of Community acquired pneumonia (CAP) among adult patients in a Tertiary Care Hospital in South India

Abstract

Background: Community acquired pneumonia (CAP) is a significant cause of morbidity and mortality among adult patients worldwide. In India, data on the bacterial etiology of CAP, antimicrobial resistance profiles, risk factors and outcomes is limited. This study was aimed at determining the bacterial etiology of CAP, their antimicrobial resistance profile, and outcomes since the choice of empirical treatment of CAP often remains challenging due to the development of drug resistant pathogens. Methods and materials: A prospective pilot study was carried out among 100 adult subjects ≥18 years of age admitted to a tertiary care hospital in South India with the diagnosis of CAP for a period of 1 year. Blood, sputum, endotracheal tip and pleural fluid were obtained for microbiological investigations within 48 h of admission. Antimicrobial susceptibility testing was performed on culture positive isolates by Kirby Bauer disk diffusion technique. Descriptive statistics and odds ratio with its 95% confidence interval was conducted using SPSS statistical software package, version 22.0. Results: A total of 100 subjects diagnosed for CAP were enrolled in the study. Majority of patients were males (63%), aged >45 years (79%), and resided in a rural area (57%). Most patients had a severe clinical course including intensive care admission (46%), ventilatory support (15%) on admission with 16% mortality. Bacterial pathogens could be identified only among 30% of the participants. 13(43%) of the isolates were multidrug resistant. Klebsiella pneumoniae [n = 16(53%)] was the most predominant isolate followed by Pseudomonas aeruginosa, Streptococcus pneumoniae, and Staphylococcus aureus. Chronic cardiovascular disease [OR 5.76 (95%CI: 1.75-18.88)], chronic liver disease [OR 6.67(95%CI: 1.47-30.27)], chronic kidney disease [OR 3.79 (95%CI: 0.97-11.7)], altered sensorium [OR 6.6(95%CI: 1.85-23.6)], sepsis and septic shock [OR 8.53 (95%CI: 2.64-27.59)] were found to be significantly associated with mortality. Conclusion: Gram negative bacteria were the predominant etiological agent responsible for CAP in our setting with multidrug resistant strains and severe clinical course. Chronic comorbid conditions must be monitored in order to increase the chance of survival among CAP patients.