title: Antibiotic resistance and genetic diversity of Escherichia coli isolates from traditional and integrated aquaculture in South China.
abstract: This study investigated antibiotic resistance profiles including antibiotic resistance frequencies, resistance genes and resistance patterns in Escherichia coli strains isolated from traditional and integrated aquaculture systems in South China by using antibiotic susceptibility testing and real time polymerase chain reaction (PCR) technique. The E. coli isolates were found to be resistant to at least one antibiotic among 12 antibiotics. Higher resistance frequencies to ampicillin, sulfamethoxazole, trimethoprime, streptomycin and tetracycline were found compared to the rest antibiotics. Among the 10 tetracycline resistance genes detected in the resistant isolates, the most prevalent tetracycline resistance genes were tetA, tetW and tetB with the frequency of 69.7%, 63.5% and 21.9%, respectively. Three sulfonamide resistance genes were detected in these resistant isolates, with their detection frequencies in the following order: sul2 (55.3%) > sul3 (28.2%) > sul1 (6.2%). Four resistance genes mainly encoding extended-spectrum β-lactamases (ESBLs) were detected in these resistant isolates, with the detection frequencies of blaTEM (28.4%) > blaOXA (9.7%) > blaCTX (9.3%) > blaCARB (5.2%) > blaSHV (0.0%). It was found that the integrated aquaculture system exhibited generally higher prevalence of antibiotic resistance than the traditional aquaculture system. An integrated aquaculture system could facilitate development of bacterial resistance and spread of the antibiotic resistance genes, and consequently become an important reservoir of resistance genes.
authors.affiliation: State Key Laboratory of Organic Geochemistry, CAS Centre for PRD Environmental Pollution and Control Research, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Tianhe District, Guangzhou, China.
authors.forename: Rui-Quan
authors.initials: RQ
authors.lastname: Zhang
authors.forename: Guang-Guo
authors.initials: GG
authors.lastname: Ying
authors.forename: Hao-Chang
authors.initials: HC
authors.lastname: Su
authors.forename: Li-Jun
authors.initials: LJ
authors.lastname: Zhou
authors.forename: You-Sheng
authors.initials: YS
authors.lastname: Liu
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D017756:Aquaculture; D002681:China; D024881:Drug Resistance, Bacterial; D004372:Ducks / Q000382:microbiology; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification; D029968:Escherichia coli Proteins / Q000235:genetics* / Q000378:metabolism; D014644:Genetic Variation; D008372:Manure / Q000382:microbiology; D008826:Microbial Sensitivity Tests / Q000662:veterinary; D060888:Real-Time Polymerase Chain Reaction / Q000662:veterinary
chemical_list: D000900:Anti-Bacterial Agents; D029968:Escherichia coli Proteins; D008372:Manure