为了解猪链球菌临床分离株的生物学特性、耐药基因与毒力基因的携带情况。采集疑似链球菌感染病死的猪肺脏和关节液，用常规方法分离细菌，通过镜检、16S rRNA序列测定分析、分子分型、动物实验鉴定分离菌的生物学特性，用药敏试验进行药物敏感度测定，并利用PCR检测耐药基因及毒力基因。结果可知，从8个养猪场的10份肺脏和关节液中共分离到10株菌，经16S rRNA序列比对和血清分型，10株分离株均为猪链球菌，其中9型7株，1型1株，其余2株为猪豕链球菌和猪生殖道链球菌;小鼠致病性试验结果显示，分离株JXNC1906、JXJJ1904和JXNC1904的毒力较强;毒力基因检测显示，JXNC2103可检出6种毒力基因，JXNC2011 株只检出mrp毒力基因，毒力型mrp+ef-gdh+sly+mmum+Orf2+2株、mrp-ef+gdh+slymmum+Orf2-4株、mrp ef gdh+slymmum+Orf2+1株、mip+ef+gdh+sly-mmum+Orf2+1株;药敏试验结果，10株分离菌的耐药性均不强，对大观霉素、恩诺沙星、丁胺卡纳、氨苄西林和头孢曲松均在中度以上敏感;耐药基因检测结果，10株链球菌分离株均能检测出氟喹诺酮类耐药基因，除JXNC1906外，其他9株还能检测出四环素类、大环内酯类以及磺胺类耐药基因，分离菌JXNC1906检测出β-内酰胺类blaTEM和氨基糖苷类ApA3'耐药基因，其他分离菌株可检测出van4、vanD、strA、strB、floR以及多重耐药基因optrA和Lsa(E)等。结果表明，从临床病死猪中分离的链球菌致病性高低不一，对临床常见药物仍较为敏感，不同分离株的耐药基因表型和毒力基因表型相差较大。本实验结果为进一步研究猪链球菌的致病机理和临床有效防控措施提供基础。
Isolation,Identification,Drug Resistance and Virulence of Streptococcus suis Strains in Jiangxi Province
In order to analyze the biological characteristics,drug resistance and virulence of clinical isolates of Streptococcus suis,lung and synovial fluid samples were collected for bacterial isolation from pigs suspected of streptococcal infection.The isolated bacteria were characterized by microscopic examination,16S rRNA sequence analysis,molecular typing,animal experiments,drug susceptibility and PCR for determining resistance genes and virulence genes.The results showed that 10 bacterial strains were obtained from 10 lung and synovial fluid samples of 8 pig farms,among which 8 strains were identified as Streptococcus suis by 16S rRNA sequence alignment and serum typing,including 7 strains of type 9 and one strain of type 1.Other 2 strains were identified as Streptococcus porcinus and Streptococcus hyovaginalis.The pathogenicity testing showed that the strains JXNC1906,JXJJ1904 and JXNC1904 had strong virulence in mice.Six virulence genes were detected in JXNC2103 and only one virulence gene mrp was detected in JXNC2011.Two strains belonged to virulence genotypemrp+ef-gdh+sly+mmum+Orf2+,4 is to mrp-ef+gdh+sly mmum+Orf2-,one strain to mrp efgdh+sly mmum+Orf2+and another strain to mrp+ef+gdh+slymmum+Orf2+.The drug susceptibility testing showed that 8 strains were not strongly resistant as they were moderately sensitive to spectinomycin,enrofloxacin,amikacin,ampicillin and ceftriaxone.In addition,fluoroquinolone resistance gene was detected in all 8 strains.Tetracycline,macrolide and sulfonamide resistance genes were found in 7 strains but not in JXNC1906.Other drug resistance genes such as β-lactam blaTEM and aminoglycoside Aph3'were found in JXNC1906 while van A,vanD,strA,strB,floR genes and multiple drug resistance genes optrA and Lsa(E)were detected in other strains.These results indicated that S.suis strains isolated from dead pigs were different in pathogenicity and even more diverse in drug resistance gene and virulence gene phenotypes.The results of this experiment laid a solid foundation for further study of pathogenesis and effective prevention and control S.treptococcus suis infection.
万方数据
维普
