【摘要】 为了解广西壮族自治区淡水养殖克氏原螯虾体内弗氏柠檬酸杆菌的感染情况，从广西各地养殖场采集克氏原螯虾，取肝胰腺进行细菌分离，利用形态学观察、生理生化试验、细菌16S rRNA和gyrB基因序列分析对分离到的菌株进行鉴定，并进行耐药性试验和ERIC-PCR指纹分析。分离获得40株弗氏柠檬酸杆菌。耐药性试验结果表明：40株弗氏柠檬酸杆菌对β-内酰胺类的抗菌药物青霉素、阿莫西林和头孢拉定等具有较强的耐药性，对四环素类抗菌药物已呈现不同程度的耐药性，而对氟喹诺酮类的氧氟沙星（禁用兽药）、环丙沙星，磺胺类的复方新诺明，林可霉素类的林可霉素、多磷类的磷霉素和氯霉素类的氟苯尼考均具有较高的敏感性。ERIC-PCR指纹分析结果表明，这40株弗氏柠檬酸杆菌共分为16个基因型，不同基因型空间分布存在一定差异，同一地区克氏原螯虾源弗氏柠檬酸杆菌也具有显著的遗传多样性。本研究结果可为克氏原螯虾弗氏柠檬酸杆菌病的有效防控提供理论依据。更多还原

【Abstract】 To understand the infection caused by Citrobacter freundii in freshwater-cultured Procambarus clarkii, bacteria were isolated from the hepatopancreas of P. clarkii collected from diverse farms across Guangxi. The isolated strains were identified by morphological observation, physiological and biochemical tests, as well as in-depth sequence analysis of the bacterial 16S rRNA gene and gyrB gene. Subsequently, drug resistance analysis and ERIC-PCR fingerprinting analysis were carried out on the identified C.freundii strains. The results of drug resistance analysis indicated that the 40 strains of C. freundii exhibited a high level of resistance toβ-lactam antibiotics, such as penicillin, amoxicillin, and cefradine. Moreover, these strains showed varying degrees of resistance to tetracycline antibiotics. In contrast, the 40 strains of C. freundii demonstrated high sensitivity to fluoroquinolones like ofloxacin(a banned veterinary drug), ciprofloxacin, as well as to sulfamethoxazole, lincomycin, fosfomycin, and florfenicol. The ERIC-PCR fingerprinting results revealed that the 40 strains of C. freundii could be classified into 16 genotypes, and there were some differences in the spatial distribution of these different genotypes. Even among the C. freundii strains isolated from P. clarkii in the same area,significant genetic diversity was observed. Collectively, the above-mentioned results can provide a theoretical basis for the effective prevention and control of C. freundii infection in crayfish.更多还原