Isolation, Identification, and Drug Resistance Analysis of Aeromonas spp. fromMicropterus salmoides in Yancheng City

In order to investigate the prevalence and drug resistance of Aeromonas spp. isolated from Micropterus salmoides in Yancheng City, 102 diseased samples of Micropterus salmoides were collected from several farms in Yancheng City for the isolation and culture of Aeromonas. The species of Aeromonas were identified by using the 16S rRNA gene amplification and sequencing method. Six virulence genes, four drug resistance genes of Aeromonas and their sensitivity to eight antimicrobial agents of aquaculture were detected. The results showed that a total of 178 strains of Aeromonas were isolated and identified from the diseased samples of Micropterus salmoides in Yancheng City, of which Aeromonas veronii and Aeromonas hydrophila accounted for 62.36% and 20.79%, respectively. The detection rates of the virulence genes ahp and act from the isolated strains were 81.46% and 78.09%, respectively. Except for ascV and epr, the detection rates of the other four virulence genes (hcp, alt, act, ahp) were more than 44%. The detection rates of the antibiotics resistance genes floR and qnrs were high, reaching 37.64% and 31.46%, respectively; The detection rates of ant and tetE were low. The sensitivity rate of Aeromonas isolates to sulfamethoxazole/trimethoprim and enrofloxacin was 60.7% and 59.6%, respectively. The resistance rate to sulfamonomethoxine sodium was the highest, which was 82%.