Bacteriological profile and antibiotic susceptibility patterns of lower respiratory tract infections in a tertiary care hospital, Central Kerala

Background and Objective: Lower respiratory tract infections (LRTIs) is one of the leading human diseases causing high morbidity and mortality worldwide. The prevalent etiological agents and their antimicrobial resistance patterns differs, both geographically and over time. With emerging resistance of respiratory bacterial pathogens to commonly used antibiotics, it is imperative to study their recent trends for effective management of these cases. Materials and Methods: A retrospective, record based study was conducted on culture and sensitivity reports of lower respiratory samples obtained in the microbiology lab during 1st January 2015- 31st December 2017. The samples were processed by standard methods for isolation and identification followed by antimicrobial sensitivity testing using Kirby Bauer disc diffusion method. Results: 288 (26.34%) of total 1093 samples were positive for bacterial culture. 244 (84.7%) were gram negative bacilli (GNB) and 44 (15.3%) were gram positive cocci. The predominant pathogen isolated was K.pneumoniae (31.1%) followed by P.aeruginosa (30.2%).The overall susceptibility of GNB was highest towards Imipenem followed by Amikacin and Piperacillin tazobactam with resistance rates of 11.5%, 26.2% and 31.6% respectively. Gram positive organisms exhibited highest susceptibility towards Vancomycin and Linezolid. 15.4 % of Staphylococcus aureus were Methicillin resistant (MRSA). Conclusion: Imipenem is the most sensitive antibiotic followed by Amikacin and Piperacillin tazobactam which can be used for empirical therapy for LRTI. The antibiotic therapy should be modified as per the culture and sensitivity report. Regular determinations of the type of bacterial pathogens and updation of antibiogram must be followed in every institution to aid in better patient management by helping the clinician in the judicious use of antibiotics.