Drug Resistance among Major Non-fermenting Gram-negative Pathogens isolated from Respiratory tract infections in a tertiary Care Hospital of South Karnataka

Non-fermenting gram-negative bacteria (NFGNB) frequently exhibit drug resistance. the purpose of this study was to determine the drug resistance pattern among the NFGNB isolates causing respiratory tract infections (Rtis). A retrospective analysis of the antimicrobial susceptibility pattern of non-fermenters causing Rtis over four years (2016-2019) was done and the change in drug resistance pattern was studied. A total of 653 cases were obtained that included 191 (29.2%) Moraxella catarrhalis, 283 (43.3%) Pseudomonas aeruginosa, and 132 (20.2%) Acinetobacter baumannii, 47 (7.2%) Stenotrophomonas maltophilia isolates. A higher resistance (82.6%) was observed for piperacillin-tazobactam and cefpirome, followed by imipenem (79.5%) and ciprofloxacin (76.5 %) for A. baumannii isolates. A sharp decline in resistance pattern for piperacillin, cefpirome, imipenem and cefoperazone-sulbactam in 2019 and an increasing resistance to gentamycin and ciprofloxacin were noted. Among P. aeruginosa isolates, 94% aztreonam and 83.4% cefoperazone-sulbactam resistance were detected. there was an increased resistance for cefpirome and piperacillin and a decreased resistance for imipenem was recorded in 2019. in cases of M. catarrhalis, 22.51% of isolates were resistant to ciprofloxacin, followed by erythromycin (18.32%) and tetracycline (17.80 %). S. maltophilia showed a 100% sensitivity for co-trimoxazole and 2.1% resistance for ciprofloxacin. A constantly changing antibiotic-resistant pattern of non-fermenters compels for a continuous update of drug-resistant trends through a longitudinal surveillance program in different geographical areas.