Gram negative organisms in community acquired respiratory tract infections

Objective: Respiratory tract infections (RTIs) are amongst the most common conditions encountered in our hospitals.The objectives of the study were to determine the frequency and antibiotic susceptibility pattern of various Gram negativebacteria (GNB) isolated from sputum samples of patients with RTIs.Methods: A descriptive, cross sectional study was carried out at the department of Microbiology, Army Medical College.Patients were diagnosed as suffering from RTIs on the basis of clinical features, radiological and laboratory findings.Sputum samples from all admitted and outdoor patients that presented to the hospital with RTIs were collected usingsterile plastic containers. Those that satisfied the criteria for inclusion were accepted and processed according to routinemicrobiological procedures. The cultures were identified and susceptibility patterns of the organisms noted.Results: Fifteen hundred and ninety six sputum samples were processed of which 549 (34.4%) yielded a positive pathogenicorganism on culture with 327 (59.6%) yielding GNB. Of these Pseudomonas aeruginosa 105 (32.1%) was the mostfrequently isolated organism followed by Heamophilus influenzae 62 (19.0%), Klebsiella pneumoniae 54 (16.5%), Acinetobacter46 (14.1%) and E. coli 41 (12.5%). Piperacillin/tazobactam, meropenem and imipenem were among the mosteffective antibiotics.Conclusion: Gram negative bacteria are becoming an increasing cause of RTIs and hence demand an increased prudenceand clinical insight in the treating clinician to keep on a lookout for these organisms as the causative agent ofRTIs. J Microbiol Infect Dis 2013; 3(1): 8-11Key words: Antibiotics, resistance, Gram negative bacteria, respiratory tract infection