Lower Respiratory Tract Infections (LTRIs): An Insight into the Prevalence and the Antibiogram of the Gram Negative, Respiratory, Bacterial Agents.

Background: Community acquired respiratory tract infections are one of the commonest health issues globally, which demand frequent visits to the family practitioners. The emergence of antibiotic resistance in the frequently isolated pathogens has complicated the use of the empiric therapy with traditional agents.

Aim: This study was focused on obtaining a comprehensive insight into the microbial profile, its prevalence and the susceptibility patterns of the gram negative bacilli isolates in lower respiratory tract infections.

Methods And Materials: Respiratory samples which were received from the patients at a Medical College Hospital in North Kerala, India were processed according to the standard protocol over a period of one year, from April 2011 to March 2012. The antimicrobial susceptibility was tested by the Kirby-Bauer disc diffusion method as per the CLSI guidelines. The data was interpreted by using the WHO Net antibiotic susceptibility surveillance soft ware Results: Out of 1750 respiratory samples, 298(17.03%) were culture positive for gram negative bacilli. The highest isolation rate was observed in the 61-80 years age group with a male preponderance and Klebsiella pneumoniae (41.95%) was found to be the predominant organism. The resistance pattern varied for different organisms. Among the different groups of antibacterial agents which were tested, levofloxacin was found to be an effective oral antibacterial against the pathogens which were isolated. The carbapenems (imipenem and meropenem), the betalactum/betalactamase inhibitors (piperacillin/tazobactum) and the aminoglycosides (amikacin) were effective among the parenteral antibacterials. The selection of the appropriate antibacterial therapy should be based on the organisms which are isolated and on the emerging resistance to the conventional therapies.

Conclusion: Owing to the increased concern which surrounds antibiotic resistance and the changing patterns of the bacterial pathogens, the ongoing surveillance of disease and a regular review of the management guidelines are critical.