Molecular Epidemiology of Carbapenemase-Producing <i>Pseudomonas aeruginosa</i> : An Iranian Referral Hospital-Based Study

In recent years, there has been a significant increase in infections caused by carbapenemase-producing strains, with carbapenem-resistant <i>Pseudomonas aeruginosa</i> (CRPA) emerging as a priority pathogen according to the World Health Organization. This study aimed to evaluate the molecular epidemiology of CRPA isolated from patients referred to Children's Medical Center in Tehran, Iran. <i>P. aeruginosa</i> isolates collected from different children's wards were screened for common carbapenem-resistant genes by polymerase chain reaction (PCR). Genetic relatedness between isolates was assessed by pulsed-field gel electrophoresis (PFGE). The study included 133 participants, with 50% being male, and revealed a median age of 2 years (interquartile range: 6 months to 6 years). Carbapenem resistance was detected in 15% of cases (<i>n</i> = 20), with CRPA isolates predominantly found in the emergency ward (60%). The median age of patients with CRPA was significantly higher than those with carbapenem-susceptible <i>P. aeruginosa</i> (6 years vs. 1 year). PCR analysis revealed metallo-β-lactamase production in 45% of CRPA isolates (<i>n</i> = 9), with <i>bla_NDM</i> being the most prevalent gene. PFGE analysis of the CRPA isolates identified three clusters (Cluster I, II, and III). Cluster I, comprising 65% of all isolates (<i>n</i> = 13), was predominantly found in the emergency ward. Notably, <i>bla_NDM</i>-producing strains were prevalent in the emergency ward. Our study highlights the significant prevalence of CRPA in the emergency ward of our hospital and underscores the importance of targeted surveillance and infection control measures to curb its spread within health care settings.