AEROBIC BACTERIOLOGICAL PROFILE OF AFB NEGATIVE SPUTUM SAMPLES AT A TERTIARY CARE MEDICAL INSTITUTE IN EASTERN INDIA

BACKGROUND Lower Respiratory Tract Infection (LRTI) is a leading cause of morbidity and mortality. Many of the patients suspected of suffering from Tuberculosis (TB) and referred to the Revised National Tuberculosis Control Programme (RNTCP) centre usually turn out to be suffering from non-tuberculous LRTIs and end up receiving no specific treatment. AIMS 1. To isolate aerobic bacterial pathogens other than Mycobacteria spp. from AFB negative sputum samples. 2. To determine the antibiotic sensitivity pattern of the isolates. SETTINGS AND DESIGN A cross-sectional study was conducted at the Microbiology Department of a tertiary care medical institute on existing data for a period of four years (2011-2015). METHODS AND MATERIAL 1015 AFB negative sputum samples were collected. Aerobic bacterial culture identification and antibiotic sensitivity tests were carried out following standard laboratory procedures. STATISTICAL ANALYSIS Data analysis was performed by using IBM SPSS version 21 software. Descriptive statistics were derived using frequency, percentage, and proportion. Chi-square test was used to calculate the P-values. RESULTS Among the 904 bacterial isolates, 613 (67.8%) were Gram-Negative Bacilli (GNB) and 291 (32.1%) were Gram-Positive Cocci (GPC). The most common organism isolated was Pseudomonas aeruginosa (38.9%) followed by Staphylococcus aureus (30%); out of which 25% were Methicillin-Resistant Staphylococcus Aureus (MRSA) and Klebsiella pneumoniae (15.7%). Pseudomonas aeruginosa was sensitive to carbapenems, aminoglycosides, and β lactam-β lactamase inhibitor combination. The GPCs were highly sensitive to linezolid and vancomycin. The Enterobacteriaceae isolates were highly susceptible to carbapenems and β lactam-β lactamase inhibitor combination. CONCLUSION Pseudomonas aeruginosa has been found to be the most commonly isolated aerobic bacteria from the AFB negative sputum samples. Antibiogram helps in specific treatment during the management of non-tuberculous LRTI as most of the isolated bacteria have been observed to be highly resistant to the commonly used antibiotics.