Molecular characterizations of aeromonas caviae isolated from catfish (Clarias sp.)

Aeromonas spp. are pathogenic bacteria which potentially cause disease to fish, including the catfish. Pathogenicity of Aeromonas spp. is determined by virulence factors controlled by the virulent genes, while the effectiveness of antibiotic treatment is influenced by the resistant genes. This study aimed to obtain molecular characterizations of Aeromonas caviae isolated from catfish (Clarias sp.). The identification of bacteria was molecularly carried out based on 16S rDNA. The virulence factors were detected based on aer/haem, alt, ast, flaA, lafA, fstA genes and the resistance were evalated based on tet-A, strA-strB and qnrA genes. The results of molecular analysis showed that MD-01 isolate was closely related to A. caviae ATCC 15468 (NR029252) with similarity rate and query of 99.86 and 99, respectively. This isolate harbored virulence genes of aer/haem, alt, ast, flaA, genes, but lafA and fstA genes were not detected. There were no resistance genes of tet-A, strA-strB and qnrA found in this isolate. Based on susceptibility to antibiotics, it was resistant to oxytetracycline, ampicillin, erythromycin and chloramphenicol, but susceptible to kanamycin (2.5 µg mL-1) and enrofloxacin (0.05 µg mL-1). This study is the first report on molecular characterization of A. caviae from catfish in Indonesia, and gives a significant contribution on the molecular characterization of A. caviae for further development of counter measure methods of this pathogenic bacterium. © 2020, BIOFLUX SRL. All rights reserved.