title: Incidence of antimicrobial-resistance genes and integrons in antibiotic-resistant bacteria isolated from eels and aquaculture ponds.
abstract: The overuse of antimicrobials in aquaculture has promoted the selection of antimicrobial-resistant bacteria. Here we investigated the abundance of antimicrobial-resistance genes and integrons in 108 strains of antibiotic-resistant bacteria isolated from eels and aquaculture ponds in China. Conventional PCR was implemented to examine common antibiotic-resistance genes, integrons, and their gene cassette arrays. The results showed that the antibiotic-resistance genes blaTEM, tetC, sulI, aadA, floR, and qnrB were detected at high percentages, as were a number of other resistance genes. Class I integrons were present in 79.63% of the strains, and 10 out of 108 isolates carried class II integrons. Class III integrons were not detected. Three strains carried both class I and class II integrons, and 73.26% of the class I integron-positive isolates contained the qacEΔ1/sul1 gene. Fourteen types of integron cassette arrays were found among class I integron-positive isolates. A new array, dfrB4-catB3-blaOXA-10-aadA1, was discovered in this study. The gene cassette array dfrA12-orfF-aadA2 was the most widely distributed. In summary, 23 different gene cassettes encoding resistance to 8 classes of antibiotics were identified in the class I integrons, and the main cassettes contained genes encoding resistance to aminoglycosides (aad) and trimethoprim (dfr). All class II integron-positive strains had only a single gene cassette array, viz. dfrA1-catB2-sat2-aadA1. High levels of antimicrobial-resistance genes and integrons in eels and auqauculture ponds suggest that the overuse of antimicrobials should be strictly controlled and that the levels of bacterial antimicrobial-resistance genes in aquaculture should be monitored.
authors.affiliation: Jimei University, Xiamen 361021, Fujian, PR China Engineering Research Center of the Modern Technology for Eel Industry, Ministry of Education, Xiamen 361021, Fujian, PR China.
authors.forename: Mao
authors.initials: M
authors.lastname: Lin
authors.forename: Xiaomei
authors.initials: X
authors.lastname: Wu
authors.forename: Qingpi
authors.initials: Q
authors.lastname: Yan
authors.forename: Ying
authors.initials: Y
authors.lastname: Ma
authors.forename: Lixing
authors.initials: L
authors.lastname: Huang
authors.forename: Yingxue
authors.initials: Y
authors.lastname: Qin
authors.forename: Xiaojin
authors.initials: X
authors.lastname: Xu
mesh_terms: D000811:Anguilla / Q000382:microbiology*; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D017756:Aquaculture; D001419:Bacteria / Q000145:classification / Q000187:drug effects*; D001424:Bacterial Infections / Q000382:microbiology / Q000662:veterinary; D024881:Drug Resistance, Bacterial; D005393:Fish Diseases / Q000382:microbiology; D061005:Ponds / Q000382:microbiology*; D014871:Water Microbiology
chemical_list: D000900:Anti-Bacterial Agents