Incidence of aac(6′)-Ib-cr Mediated by Class 1 Integrons in Aeromonas Species Isolated from Diseased Oreochromis niloticus

THE virulent clonal populations of Aeromonas spp. are recognized as the etiological agent of motile Aeromonas septicemia (MAS) outbreaks in aquaculture. This study aimed to identify Aeromonas spp. isolated from diseased Oreochromis niloticus , evaluate their virulence factors, and assess their resistance to antimicrobial agents. Species identification was conducted through analysis of the gyrB genes. Antibiotic resistance phenotypes and genotypes (blaTEM , blaCTX-M , aac(61)-Ib-cr , and intI1) were determined. The results indicated that 44,4% of the isolates belonged to A. veronii , 38.9% to A. sobria , and 16.7% to A. hydrophila. PCR analysis revealed the presence of blaTEM , aac(61)-Ib-cr , and intI1 genes among 100%, 77.8%, and 83.3% of the isolates, respectively, while blaCTX-M was not detected. In conclusion, the detection of the aac(6')-Ibcr gene in aquatic environments can serve as a significant indicator of multi-drug resistance (MDR). The presence of MDR, particularly mediated by integrons in Aeromonas , raises serious concerns regarding potential health risks. Moreover, the emergence of MDR complicates the efficacy of therapeutic treatments for infections. Therefore, adopting a comprehensive One Health approach becomes imperative to effectively control the spread of MDR and mitigate its impact on public health.