Molecular characterization and genotypic diversity of extensively drug-resistant Acinetobacter baumannii from endotracheal aspirates in a pediatric intensive care unit in Sulaimani, Iraq.

BACKGROUND

Extensively drug-resistant (XDR) Acinetobacter baumannii poses a significant threat in pediatric intensive care units (PICUs), particularly in regions with limited surveillance data. This study characterized the bacterial profile of endotracheal aspirate samples from a PICU in Sulaimani, confirmed A. baumannii identification using blaOXA-51 PCR, assessed antimicrobial resistance patterns, and determined genotypic diversity using ERIC-PCR.

METHODS AND

RESULTS

From August 2023 to March 2025, 100 consecutive Gram-negative isolates were recovered from mechanically ventilated pediatric patients. VITEK2 was used for identification and susceptibility testing. XDR Acinetobacter isolates underwent molecular confirmation via blaOXA-51 PCR, and confirmed isolates were genotyped using ERIC-PCR with UPGMA analysis. Among the 100 total isolates, A. baumannii accounted for 21 isolates alongside Pseudomonas aeruginosa (n = 33) and Klebsiella pneumoniae (n = 20). Given its clinical significance, A. baumannii was selected for further molecular characterization. Overall, 26 isolates exhibited XDR phenotypes, 12 of which were A. baumannii by VITEK2; 10 were confirmed by blaOXA-51 PCR (83.3%). All confirmed isolates were resistant to β-lactams, carbapenems, aminoglycosides, and fluoroquinolones, while remaining susceptible to colistin. ERIC-PCR revealed one dominant clone (Cluster A, 50%), two minor clusters (20% each), and one singleton (10%), indicating moderate genetic diversity with evidence of sustained clonal circulation.

CONCLUSIONS

This study provides the first molecular epidemiological characterization of XDR A. baumannii in an Iraqi PICU, revealing clonal persistence of a successful epidemic strain and critical gaps in phenotypic identification. These findings emphasize the need for routine molecular surveillance, targeted infection control, and antimicrobial stewardship in resource-limited settings.