Phenotypic and Genotypic Detection of Gram-Negative Bacteria Isolated from Urinary Tract Infections in Intensive Care Unit Patients in Duhok City.

Urinary tract infections are among the most prevalent hospital-acquired infections, particularly in intensive care unit patients, and are often linked to increased morbidity, prolonged hospitalization, and rising antimicrobial resistance. This study aimed to identify Gram-negative bacteria from intensive care unit urine samples using both phenotypic and genotypic methods to enhance diagnostic accuracy and evaluate antimicrobial resistance patterns. The cross-sectional study was conducted in Duhok City, involving 230 urine samples collected from 628 intensive care unit patients. Conventional microbiological techniques were used for initial culture, and the VITEK 2 system for identification and antibiotic susceptibility testing. Genotypic confirmation was then applied to verify the identity of Gram-negative isolates. Out of the 230 samples, 69 (30%) showed positive cultures, with 40 identified as Gram-negative. Phenotypically, Escherichia coli was the most frequent (65%), followed by Klebsiella pneumoniae (25%). Polymerase chain reaction analysis confirmed E. coli in 70% of isolates, while Pseudomonas aeruginosa was not confirmed genotypically. Resistance analysis revealed that 60% of the isolates were multidrug-resistant, 30% were susceptible, and 5% each showed extensive or pan-drug resistance. The results showed notable discrepancies between phenotypic and genotypic identification, particularly in species misclassification, indicating that phenotypic methods alone may be insufficient. The predominance of E. coli and K. pneumoniae highlights their role as key uropathogens in intensive care unit patients. These findings stress the importance of combining phenotypic and genotypic approaches to improve diagnostic precision and guide effective antimicrobial therapy in critical care settings.