Abstract
BACKGROUND: Pseudomonas aeruginosa is an opportunistic pathogen in aquaculture that can cause significant infections and spread through genetically diverse strains. AIM: This study investigated the clonal relatedness and genotyping analysis of P. aeruginosa isolates from infected salmon trout in various trout farms using random amplified polymorphic DNA (RAPD) polymerase chain reaction (PCR) fingerprinting. METHODS: A total of 35 P. aeruginosa isolates were collected from lesions in different organs of trout from seven farms across Sheladize and Amedi districts in Duhok province, Iraq. RAPD-PCR was performed using specific primers, and amplified DNA fragments were analyzed using GelJ software to generate a dendrogram based on Unweighted Pair Group Method with Arithmetic Mean clustering. RESULTS: The results showed a genetic similarity range of 50.00%-100.0%, identifying 33 unique genotypes. Notably, two isolates from different farms and geographic locations shared the same genotype, indicating the potential for bacterial transmission. However, the remaining strains were grouped into a single genotype due to the significant genetic diversity seen in their DNA. CONCLUSION: The findings emphasize the role of bacterial clonal differentiation in the spread of P. aeruginosa infections in fish farms, driven by multiple transmission sources. This genetic variation highlights the need for enhanced biosecurity measures to mitigate P. aeruginosa spread in aquaculture settings.