CHANGING TRENDS OF ANTIBIOTIC SENSITIVITY PROFILE AMONG GRAM NEGATIVE BACTERIA ISOLATED FROM URINE SAMPLES IN CRITICAL CARE PATIENTS OF A TERTIARY CARE HOSPITAL

Abstract

Urinary tract infections (UTIs) are among the most frequent infections in humans, particularly in intensive care units (ICUs) due to impaired immunity and invasive procedures. The changing resistance patterns of bacteria pose a major public health concern, often leading to therapeutic failure. This study aimed to determine the prevalence of UTIs among ICU patients, identify the bacterial profile, assess antimicrobial sensitivity, and evaluate ESBL, AmpC, and MBL production among multidrug-resistant (MDR) Gram-negative bacilli. A total of 1,908 clinical samples were processed over four years, 634 (33.2%) samples showed positive growth, of which only 527(89%) yielded Gram negative bacteria , out of which 427 MDR Gram-negative were selected for further study. Identification and antimicrobial susceptibility testing were performed, followed by screening for β-lactamase production. Among the isolates, Escherichia coli was most common (60%), followed by Klebsiella pneumoniae (19%) and Pseudomonas aeruginosa (12%). E.coli showed maximum sensitivity to Ceftazidime (24%) among third-generation Cephalosporins, Norfloxacin (24%) among fluoroquinolones, Amikacin (63%) among aminoglycosides, and meropenem (68%) among Carbapenems. Sensitivity to the BL-BLI combination Piperacillin/Tazobactam was 56%. Klebsiella pneumoniae demonstrated 20% sensitivity to Ceftazidime, 23% to Ciprofloxacin, and 65% to Gentamicin. β-lactamase production was detected in 340 strains. Of these, 175 (40.9%) were ESBL producers, 106 (24.8%) AmpC producers, and 59 (13.8%) metallo-β-lactamase (MBL) producers. Co-production of ESBL, AmpC, and MBL was observed in 102 (23.9%) strains, predominantly in E. coli. The high prevalence of β-lactamase producing isolates in ICU patients highlights the urgent need for continuous surveillance, strict antibiotic stewardship, and robust infection control measures to mitigate the growing burden of antimicrobial resistance.