Antimicrobial Resistance Patterns of Enterobacterales Isolates: A Comprehensive Analysis

Abstract

notably urinary tract infections (UTIs), bloodstream infections (BSIs), and pneumonia. Knowledge of their antimicrobial resistance profiles is essential for optimizing treatment.

Aim: To evaluate the prevalence and antimicrobial resistance patterns of carbapenemase-producing Enterobacterales isolated from clinical specimens.

Objectives: This study assesses antimicrobial resistance patterns in Enterobacterales species isolated from clinical specimens at the Integral Institute of Medical Sciences and Research (IIMSR), Integral University, Lucknow.

Methods: Over 2022–2023, 357 clinical isolates were obtained and identified through standard biochemical methods. Antimicrobial susceptibility testing (AST) was conducted following Clinical and Laboratory Standards Institute (CLSI) guidelines using the disk diffusion method, focusing on commonly used antibiotics like ampicillin, ciprofloxacin, cephalosporins, and carbapenems. Susceptibility data were analyzed with SPSS, comparing patterns across different specimen types.

Results: Of the 357 Gram-negative bacterial isolates, direct smears and Gram staining confirmed the presence of Gram-negative bacilli and pus cells. Notably, Escherichia coli from urine samples showed 100% resistance to norfloxacin and 48.28% to nitrofurantoin, while Klebsiella pneumoniae isolates from urine exhibited 100% resistance to both antibiotics. A single Citrobacter freundii isolate displayed similar resistance patterns. Tigecycline showed relatively low resistance rates, with 17.02% in E. coli, 40.74% in K. pneumoniae, and 20% in C. freundii. Carbapenem resistance was found at 100% in both E. coli and K. pneumoniae isolates, emphasizing substantial resistance in urinary pathogens, particularly to commonly prescribed antibiotics such as norfloxacin and nitrofurantoin.

Conclusion: The findings underscore the critical need for ongoing monitoring of antimicrobial resistance in Enterobacterales at IIMSR. The observed resistance differences among clinical specimens highlight the importance of tailored therapeutic approaches.

This research will aid clinicians in selecting empirical therapies and inform antimicrobial stewardship efforts. Further studies are essential to investigate resistance mechanisms in these pathogens.