| Close to2/3of the aquaculture products are produced in China where regulatory controlsare weak and antibiotics are often abused. The rapid emergence of antibiotic-resistant (ART)bacteria has been a major public health concern. Studies are needed to examine theprevalence of antibiotic resistant bacteria associated with aquaculture products and thedissemination of antibiotic resistant gene. The study will provide basic research data andimformation for the establish of food safety control.The current study examined the prevalence of antibiotic resistant (ART) bacteria andantibiotic resistance (AR) genes in several aquaculture products from retail markets inGuangzhou, China. Resistant bacteria to representative antibiotics were screened on selectivemedia supplemented with the corresponding drugs. Representative AR genes in these isolates,as well as the identities of the AR gene carriers were determined by PCR and16S rRNAsequence analysis. AR persistence, mobility and profiles were further characterized inselected resistant isolates. The results showed that (1) ART commensal bacteria were foundin100%of the products examined. Among505multi-drug resistant isolates examined, closeto contained the class1integrase-encoding and sul1genes,15%contained sul2, and5%with tet(E). Incidence of β-lactamase-encoding genes blaTEM, blaCMY, as well aserythromycin resistance determinants ermB and ermC were4.5%,1.7%, and1.3%and0.3%,respectively.(2) Most of the ART isolates identified from rinsing water and intestines wereAeromonas sp. and Enterobacter sp., respectively.(3) Plasmid-associated class1integraseand AR encoding genes were identified in several ART isolates by Southern hybridization.Three multi-drug resistance encoding plasmids were transferred into Escherichia coli DH5αby chemical transformation and led to acquired AR in the transformants. In addition, the ARtraits in many isolates were quite stable, even in the absence of the selective pressure. |
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