Dynamics of bacterial community and antibiotic resistance genes in the aquaculture ponds of channel catfish (Ietalurus Punetaus): An association with the mobile genetic elements and environmental factors

Abstract

Aquaculture is a vital link between aquatic products and public health, but the effects of potentially hazardous factors in aquaculture have been grossly underestimated. In this study, a total of 15 potentially pathogenic bacteria (PPB) and 39 antibiotic resistant bacteria (ARB) were identified in the aquaculture pond environment based on 16S rRNA genes. And, 89 antibiotic resistance genes (ARGs) subtypes combined with eight mobile genetic elements (MGEs) and nine environmental factors were also investigated. Cyanobacteria and Proteobacteria were observed as the dominant phyla at different culture stages. The total abundances of PPB and ARB showed an increasing trends from juvenile to harvesting culture stage, revealing that they are widely disturbed in aquaculture ponds. Further, intI-1 exhibited the highest abundance among MGEs and sul1 had the highest abundance among ARG subtypes. The OLS regression analysis showed significant positive correlations among abundances of MGEs and ARGs. The RDA demonstrated that the temperature, transparency and Chlorophyll a exhibited significant correlations with different bacterial phylum, and the positive correlation between MGEs (intI-1) and ARGs (ereA and sul1) highlighted their horizontal migration via associated bacterial communities (e.g. Proteobacteria). The co-occurrence patterns indicated that the MGEs (intI-1 and IS613) and the genus Pseudoramibacter, Citrobacter, Mycobacterium, Moraxella, Pseudoalteromonas, Eikenella, Providencia, and Proteus may play a leading role in the distribution of ARGs during the cultivation of channel catfish. Our results provide a systematic understanding of the rational regulation of PPB, as well as the prevention of ecological and health risks associated with ARB and ARGs in aquaculture.