2020—2022年宁波市大黄鱼病原菌耐药状况分析

Analysis on the antibiotic resistance of pathogens separated from Pseudosciaena crocea in Ningbo City,Zhejiang Province from 2020 to 2022

为掌握近几年宁波市大黄鱼主要病原菌的种类及其耐药趋势,本研究于2020—2022年在宁波市大黄鱼主要养殖基地采集患病鱼体进行病原菌的分离鉴定,并对分离的病原菌进行恩诺沙星、硫酸新霉素、甲砜霉素、氟苯尼考、盐酸多西环素、氟甲喹、磺胺间甲氧嘧啶钠、磺胺甲噁唑+甲氧苄啶8种抗菌渔药最低抑菌浓度(Minimum inhibitory concentration,MIC)的测定,比较各病原菌对药物的感受性。结果表明,近3年从大黄鱼体内共分离到7种、58株病原菌,主要病原菌为杀香鱼假单胞菌、哈维氏弧菌和鰤鱼诺卡氏菌,占总菌株数的74.1%,其中哈维氏弧菌和鰤鱼诺卡氏菌每年都有被分离到。100%分离的菌株对盐酸多西环素敏感,所有菌株对该药物的感受性均分布在MIC≤4.00 mg/L,耐药率为0%;相较而言,病原菌对氟苯尼考及磺胺类药物的耐受浓度较高,尤其磺胺类药物MIC普遍为64.00~1024.00 mg/L。另外,从病原菌耐药性年度变化可知,鰤鱼诺卡氏菌每年对药物的耐受性呈逐年递增的趋势。因此,虽然病原菌普遍对盐酸多西环素、硫酸新霉素、恩诺沙星敏感,其可作为防治大黄鱼多数病原菌的优选药物,但必须严格按照药敏试验结果及结合药代学、药效学确定剂量和药程,才能尽可能避免耐药菌株的产生。

In order to master the types and antibiotic resistance trend of the main pathogen of P.crocea in Ningbo City,Zhejiang Province in recent years,the infected fishes were collected from the main breeding sites of P.crocea in Ningbo from 2020 to 2022 for isolation and identification of pathogens.In the meantime,the minimum inhibitory concentration(MIC)of antibiotics(enrofloxacin,neomycin sulfate,thiamphenicol,florfenicol,doxycycline hydrochloride,fluoroquine,sulfamethoxazole sodium,sulfamethoxazole+trimethoprim)were determined to compare the susceptibility of each pathogen to the drug.The results showed that 7 species and 58 strains of pathogens were isolated from P.crocea in recent three years.The main pathogens were Pseudomonas plecoglossicida,Vibrio harveyi and Nocardia seriolea,accounting for 74.1%of the total bacterial strains.V.harveyi and N.seriolae were isolated every year.The isolated strains were 100%sensitive to doxycycline hydrochloride.The susceptibility of all strains to this drug was distributed at MIC≤4.00 mg/L and the drug resistance rate was 0%.In comparison,the drug tolerance concentration of pathogens to florfenicol and sulfonamides was relatively high,especially the MIC of sulfonamides was generally between 64.00-1024.00 mg/L.In addition,from the annual change in drug resistance of pathogen,it could be seen the drug resistance of N.seriolae was increasing year by year.Therefore,although the pathogens were generally sensitive to doxycycline hydrochloride,neomycin sulfate and enrofloxacin,which could be used as the preferred drug for controlling most pathogens in P.crocea,the dose and course must be determined strictly according to the results of drug sensitivity test and in combination with pharmacokinetics and pharmacodynamics,in order to avoid the emergence of drug-resistant strains as much as possible.