Abstract
BACKGROUND: Empirical antibiotic therapy is the mainstay of management of adult community-acquired pneumonia (CAP) globally. Knowledge of prevalent pathogen (bacterial) profile and drug susceptibility pattern is very essential for appropriate management of CAP cases, which again calls for regular update of pathogen profile in a given locality. This study was to identify the bacterial etiology of CAP cases and their antibiotic susceptibility pattern. METHODS: This cross-sectional study was done on adult CAP patients from medicine, respiratory medicine, and intensive care unit area in our tertiary care hospital between May 1, 2015, and October 30, 2016. Subjects were enrolled continuously, and expectorated sputum, bronchoalveolar lavage fluid, and blood culture were performed. Urine antigen test was done for Streptococcus pneumoniae and Legionella pneumophila. Three types of ELISA (IgM, IgG, and IgA) were performed for atypical agents (Mycoplasma, Chlamydia, and Legionella) of CAP. Isolates obtained from culture of Sputum/BAL/Blood were further processed for antibiotic susceptibility testing - by disc diffusion as well as E-test method (latter for MIC i.e. minimum inhibitory concentration, determination). RESULTS: About 574 subjects were included, and in 266 (46.3%) cases, bacterial pathogen could be detected. Klebsiella pneumoniae (33.6%) and S. pneumoniae (32.9%) were the predominant agents identified. Atypical agents (Mycoplasma, Legionella, and Chlamydia) were at 15.1%. A high proportion of pneumococci isolates were multidrug resistant (52.6%). Resistance to beta-lactams, macrolide, and other agents was on the higher side, but fluoroquinolones were found to be less resistant (15.8%-21.1%). Extended-spectrum beta-lactamase (among Klebsiella isolates) and methicillin-resistant Staphylococcus aureus were also detected. CONCLUSION: A moderate-to-high degree of drug-resistant in adult CAP was evident, which is detrimental in effective empirical management of such cases. Urgent implementation of antibiotic stewardship scheme is the need of the hour.