Isolation, identification and antibiotic resistance analysis of intestinal strains of aquaculture Litopenaeus vannamei in surrounding areas of Tianjin

With the widespread use of antibiotics in aquaculture, the bacterial antibiotic resistance has become a main problem in environment and food safety. This paper aims to analyze the statistical information of shrimp intestine bacterial drug resistance in Tianjin area, and to provide theoretical guidance for the shrimp disease control and improving the safety of aquatic products. Shrimp intestine organisms were isolated and cultured, then the bacterial antibiotic resistance and the antibiotic resistance genes (ARGs) of cultured Litopenaeus vannameiwere determined in the breeding base of Jinnan, Hangu and Xiqing districts of Tianjin city. Among the total isolated 1 219 strains, 215 strains were identified, and were classified into 56 different species, mainly Bacillus, Vibrio parahaemolyticus, Staphylococcus, Klebsiella pneumoniae, V. Xiluo, V. alginolyticus, Shewanella sp., Enterobacter hormaechei, Kurthia sp., Pseudomonas stutzeri, Rhodobacter capsulatus, Serratia liquefaciens, Acinetobacter sp., Pseudomonas, Pseudoalteromonas whanghaensis, V. cholerae. 215 strains were selected to analyze the antibiotics sensitivity. The experiment results showed that the antibiotic resistance of the intestinal bacterias was universal, especially to the beta lactam ampicillin, bacitracin glycopeptide, quinolones of lomefloxaxin and sulfonamides resistance. Therefore, four main kinds of antibiotic resistance gene (streptomycin:strA-strB, sulfonamidesSulI, SulII, SulIII, tetracyclines: TetA, TetC, TetG, penicillin:blaoXA-1, blaPSE-1, blaTEM) and integron (inT1 and inT2) of 82 strains with crossed antibiotic resistance were further determined. The results showed that all of the drug-resistant strains were detected with antibiotic resistance genes positive. The positive rate of resistance genes of sulfonamides, penicillin and tetracycline was 63%, 61.4% and 35.4%, respectively. And only tetA was detected in tetracycline resistance genes. The positive rate of integron gene was 42.1%. Among them, 67.1% of the strains had multiple resistance genes.