Introduction: Lower respiratory tract infections (LRTI) are common human diseases, the morbidity and mortality of which varies  depending on  the underlying etiological agent and its virulence. With emerging drug resistance of organisms to commonly used antibiotics, it is imperative to study their recent trends, for effective management of these cases.

Materials and Methods: The study was done in the respiratory samples received at the microbiology department , from patients with LRTIs attending outpatient clinic at a tertiary care centre, Puducherry. The samples were processed by standard methods for isolations and identification followed by antimicrobial sensitivity testing using Kirby Bauer disc diffusion method.

Results: Nearly 109 respiratory samples were processed during the study period from July to October, 2014. Of the samples tested significant pathogens were isolated in 71(65.14%) cases. Among the gram negative bacteria grown i.e 42.56%  , the predominant pathogen isolated was Klebsiella pneumoniae  (52%), followed by Pseudomonas aeruginosa (25%), Escherichia coli (18%) and  Acinetobacter species (5%). The antimicrobial resistance pattern showed high resistance rates to third generation cephalosporins and aminoglycosides.

Conclusions: In this study it was observed that significant number of gram negative isolates from the community acquired LTRI were showing resistance to third generation Cephalosporins. Hence it is advised to undertake routine testing in the clinical microbiology laboratory for screening of multidrug resistant isolates like ESBL and MBL producing organisms to give necessary information to the clinicians for accurate management of these infections.

Keywords: Lower respiratory tract infection , Klebsiella species, Gram negative bacterial isolates.

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