Molecular study of carbapenem-resistant Pseudomonas aeruginosa causing wound infection in an Egyptian tertiary...

Pseudomonas aeruginosa is a bacterial pathogen that causes various acute and chronic human infections, including wound and burn infections, with serious consequences. This study aimed to determine the antimicrobial resistance profile of P. aeruginosa isolated from wound infections and investigate the molecular mechanism of carbapenem resistance.

Forty-nine P. aeruginosa wound infection isolates were collected from a tertiary care hospital in Cairo, Egypt, from September 2022 to September 2023. The resistance profile of P. aeruginosa isolates was determined by the disc diffusion method, minimum inhibitory concentration (MIC) of meropenem susceptibility, and detection of metallo‑β-lactamase (MBL) production by imipenem-EDTA combined disc test. Polymerase chain reaction (PCR) was utilized to identify the carbapenem resistance genes, blaKPC, blaNDM-1, and blaOXA-48 among carbapenem-resistant P. aeruginosa (CRPA) isolates. The ERIC-PCR was used to assess the genetic diversity and relatedness among CRPA isolates. The results were presented as descriptive statistics in percentages and relative frequencies.

The findings revealed that 44.9% (22/49) of P. aeruginosa isolates were multidrug-resistant (MDR), meropenem resistant, and MBL producers. PCR assays showed that out of 22 CRPA isolates, six isolates (6/22, 27.3%) harbored the blaNDM-1 gene, and three (3/22, 13.6%) carried the blaOXA-48 gene, while none of the isolates had the blaKPC. ERIC-PCR-based genotyping demonstrated a significant molecular heterogeneity, indicated by 16 ERIC-based patterns or fingerprints among 22 CRPA isolates.

The resistance profile demonstrated by P. aeruginosa in wound infections suggests the need for effective hospital infection control and antibiotic policies in developing countries. The CRPA isolates were polyclonal, highlighted by their substantial genetic heterogeneity.