Abdullah I Abdullah I
Antimicrobial resistance (AMR) in Gram-negative pathogens poses a critical threat in intensive care units (ICUs). This retrospective observational study aimed to determine the prevalence and phenotypic resistance profiles of extended-spectrum β‑lactamase (ESBL)-producing and carbapenem‑resistant Klebsiella pneumoniae among ICU patients at a tertiary hospital in southwestern Saudi Arabia (2020-2021). Clinical specimens (n=179) from patients with hospital‑acquired infections were processed using standard culture, Vitek 2 identification, and phenotypic confirmatory tests (combination disc test for ESBLs and modified carbapenem inactivation method for carbapenemase). Of 543 total samples, 49 (9.0%) were identified as K. pneumoniae. ESBL production was detected in 15/49 (30.6%) and carbapenemase production in 6/49 (12.2%) of isolates. The highest resistance rates were observed against piperacillin‑tazobactam (55.1%), cefotaxime (55.1%), imipenem (53.0%), and meropenem (53.0%), while tigecycline (100% susceptibility) and amikacin (93.9% susceptibility) remained the most effective agents. Notably, susceptibility to trimethoprim‑sulfamethoxazole was 83.7% (corrected figure). Children under 10 years and adults aged 21-40 years showed the highest infection rates. The alarmingly high prevalence of ESBL and carbapenemase phenotypes, coupled with significant multidrug resistance, underscores the urgent need for routine molecular surveillance and targeted antibiotic stewardship in this region. Rapid phenotypic screening combined with genotypic confirmation is essential to guide empirical therapy and curb the spread of these high‑risk clones in critically ill populations.