# The Burden of Antimicrobial‐Resistant Pseudomonas aeruginosa Isolates in Children With Cystic Fibrosis: Molecular Characterization and Genotyping Analysis

## TL;DR

This study finds high rates of drug-resistant Pseudomonas aeruginosa in children with cystic fibrosis in Iran, highlighting the need for better infection control and treatment strategies.

## Contribution

The study provides new insights into the genetic diversity and resistance patterns of Pseudomonas aeruginosa in a pediatric cystic fibrosis population in Iran.

## Key findings

- 94.9% of Pseudomonas aeruginosa isolates were nonsusceptible to at least one antimicrobial agent.
- blaVIM was the most frequently identified carbapenemase gene among resistant isolates.
- RAPD–PCR revealed significant genetic heterogeneity, grouping isolates into 24 distinct clusters.

## Abstract

Pseudomonas aeruginosa poses a significant therapeutic challenge in pediatric patients with cystic fibrosis (CF) due to increasing multidrug resistance (MDR) and carbapenem resistance, underscoring the need for surveillance to guide treatment strategies. In this study, sputum and throat swab samples were collected from inpatient and outpatient CF children with pulmonary infection at the Children's Medical Center in Tehran, Iran. Isolates were identified using standard culture and biochemical methods, followed by antimicrobial susceptibility testing. Carbapenemase production was assessed phenotypically and by molecular detection of resistance genes, and genetic diversity was also evaluated using Random Amplified Polymorphic DNA (RAPD)–polymerase chain reaction (PCR). A total of 117 P. aeruginosa isolates were recovered (prevalence 17.41%), of which 94.9% were nonsusceptible to at least one antimicrobial agent. Carbapenem‐resistant P. aeruginosa (CRPA) and MDR isolates accounted for 24.8% and 23.1% of isolates, respectively. Carbapenemase gene coexistence was significantly associated with MDR (ρ = 0.227, p = 0.014) and CRPA (ρ = 0.314, p = 0.001). Metallo‐β‐lactamase production was detected in 13.7% of isolates, while blaVIM was the most frequently identified carbapenemase gene (59%). RAPD–PCR demonstrated marked genetic heterogeneity, grouping isolates into 24 distinct clusters. Overall, the substantial burden of MDR and CRPA identified at this tertiary pediatric center highlights an urgent need for stricter antimicrobial stewardship, enhanced infection control measures, and ongoing surveillance to mitigate resistance spread and preserve therapeutic effectiveness in this vulnerable population. These findings warrant multicenter investigation to determine whether similar patterns exist across other Iranian pediatric CF facilities.

This study highlights the prevalence of multidrug‐ and carbapenem‐resistant Pseudomonas aeruginosa in pediatric cystic fibrosis patients, along with the presence of carbapenemase‐encoding genes and genetic profiles, suggesting clonal spread. These findings underscore the urgent need for surveillance and strategies to combat resistant strains and improve treatment outcomes.