摘要
在自然感染无乳链球菌(Streptococcus agalactiae)的罗非鱼(Oreochromis niloticus)成鱼、稚鱼和自然携带无乳链球菌的罗非鱼体内分别获得14株、4株和2株无乳链球菌。临床和组织病理学分析显示,罗非鱼成鱼出现无规则游动,脑、眼眶、鳃和鳍条充血,眼球突出、白浊,内脏器官肿大、充血,以肾小管玻璃样变性、脑膜炎和心外膜炎等组织病理学变化为特征;罗非鱼稚鱼体表无明显症状,但部分内脏器官呈现肿大、充血现象,以脾脏血管区出血、肾小管上皮细胞变性、脑组织炎症反应较轻为其主要组织病理学特征。此外,罗非鱼胃固有层内及稚鱼肝脏组织中有大量的嗜酸性粒细胞浸润,可观察到无乳链球菌在成鱼的脑、心脏以及稚鱼肝脏中增殖;自然携带无乳链球菌的罗非鱼临床症状和组织学病变均不明显。PCR检测发现,各无乳链球菌毒力基因谱相同,但自然感染无乳链球菌的罗非鱼成鱼、稚鱼和自然携带无乳链球菌的罗非鱼的病理学损伤差异显著。
We isolated 14, 4 and 2 strains of Streptococcus agalactiae from naturally infected adult and juvenile tilapia as well as tilapia naturally carrying S. agalactiae, respectively. The clinical signs and anatomy changes of adult tilapia were as follows: erratic swimming, congestion of brain, eyeballs, gills and fins, exophthalmia, corneal opacity and swelling of visceral organs, which were characterized by histopathological changes with tubular hyaline degeneration, meningitis and epicarditis. The clinical symptoms of juvenile tilapia were not obvious, but some of the internal organs showed swelling and congestion, characterized by main histopathological features of hemorrhage of spleen vascular area, degenerated renal tubular epithelial cells and milder inflammatory response in brain tissue. In addition, eosinophil infiltration was found in the lamina propria of tilapia and in the liver of juvenile fish. It was observed that S. agalactiae proliferated in the brain and heart of adult fish and in the liver of juvenile tilapia, respectively. The clinical symptoms and histological lesions in tilapia carrying S. agalactiae were not obvious. The results of PCR detection show that all the S. agalactiae strains had the same virulence gene profiles, but there were significant differences in pathological damages among adult fish, juvenile fish and tilapia carrying S. agalactiae.
引文
[1]顾慧敏,胡引.1例分娩期合并无乳链球菌败血症患者的抢救及护理[J].中国实用护理杂志,2014,30(12):56-57.
[2]SANZROJAS P,CABEZAOSORIO L,HERMOSA C,et al.Acute meningitis by Streptococcus agalactiae in a immunocompetent male[J].Rev Esp Quim,2013,26(1):78-79.
[3]JAWA G,HUSSAIN Z,da SILVA O.Recurrent late-onset group B Streptococcus sepsis in a preterm infant acquired by expressed breastmilk transmission:a case report[J].Breastfeed Med,2013,8(1):134-136.
[4]VILLENA R M A,OLALLA S J,de la TORRE L J,et al.Streptococcus agalactiae induced cavitated pneumonia[J].Rev Clin Esp,2009,209(5):252-254.
[5]ELLIOTT J A,FACKLAM R R,RICHTER C B.Whole-cell protein patterns of nonhemolytic group B,type Ib,streptococci isolated from humans,mice,cattle,frogs,and fish[J].J Clin Microbiol,1990,28(3):628-630.
[6]EVANS J J,BOHNSACK J F,KLESIUS P H,et al.Phylogenetic relationships among Streptococcus agalactiae isolated from piscine,dolphin,bovine and human sources:a dolphin and piscine lineage associated with a fish epidemic in Kuwait is also associated with human neonatal infections in Japan[J].J Med Microbiol,2008,57(11):1369-1376.
[7]GENG Y,WANG K Y,HUANG X L,et al.Streptococcus agalactiae,an emerging pathogen for cultured ya-fish,Schizothorax prenanti,in China[J].Transbound Emerg Dis,2012,59(4):369-375.
[8]崔静雯,汪开毓,贺扬,等.无乳链球菌感染尼罗罗非鱼的脑膜炎模型[J].水产学报,2015,39(12):1883-1893.
[9]王瑞,李莉萍,黄婷,等.罗非鱼组织内无乳链球菌实时荧光定量PCR检测方法建立[J].南方水产科学,2015,11(3):41-46.
[10]卢迈新,黎炯,叶星,等.广东与海南养殖罗非鱼无乳链球菌的分离、鉴定与特性分析[J].微生物学通报,2010,37(5):766-774.
[11]HEMáNDEZ E,FIGUEROA J,IREGUI C.Streptococcosis on a red tilapia,Oreochromis sp.,farm:a case study[J].J Fish Dis,2009,32(3):247-252.
[12]祝璟琳,杨弘.鱼源无乳链球菌致病机理研究进展[J].广东海洋大学学报,2013,33(6):92-96.
[13]CHIDEROLI R T,AMOROSO N,MAINARDI R M,et al.Emergence of a new multidrug-resistant and highly virulent serotype of Streptococcus agalactiae in fish farms from Brazil[J].Aquaculture,2017,479:45-51.
[14]韦现色,林勇,杨慧赞,等.广西罗非鱼链球菌病的流行及防治[J].广西畜牧兽医,2013,29(1):57-60.
[15]方伟,梁宇恒,宁丹,等.广东地区感染养殖罗非鱼的无乳链球菌分子分型研究[J].中山大学学报(自然科学版),2016,55(2):97-101.
[16]SU Y L,FENG J,LIU C,et al.Dynamic bacterial colonization and microscopic lesions in multiple organs of tilapia infected with low and high pathogenic Streptococcus agalactiae strains[J].Aquaculture,2017,471:190-203.
[17]PATRAS K A,NIZET V.Group B streptococcal maternal colonization and neonatal disease:molecular mechanisms and preventative approaches[J].Front Pediatr,2018,6:27.
[18]LECLERCQ S Y,SULLIVAN M J,IPE D S,et al.Pathogenesis of Streptococcus urinary tract infection depends on bacterial strain andβ-hemolysin/cytolysin that mediates cytotoxicity,cytokine synthesis,inflammation and virulence[J].Sci Rep-UK,2016,6:29000.
[19]GENDRIN C,LEMBO A,WHIDBEY C,et al.The sensor histidine kinase RgfC affects group B streptococcal virulence factor expression independent of its response regulator RgfA[J].Infect Immun,2015,83(3):1078-1088.
[20]李庆勇,可小丽,卢迈新,等.罗非鱼无乳链球菌C5a肽酶(ScpB)的原核表达及其免疫原性[J].中国水产科学,2014,21(1):169-179.
[21]曾祖聪,可小丽,卢迈新,等.罗非鱼无乳链球菌LrrG-Sip融合蛋白免疫原性研究[J].南方水产科学,2017,13(3):51-57.
[22]ZHANG D,LI A,GUO Y,et al.Molecular characterization of Streptococcus agalactiae in diseased farmed tilapia in China[J].Aquaculture,2013,412(6):64-69.
[23]KANNIKA K,PISUTTHARACHAI D,SRISAPOOME P,et al.Molecular serotyping,virulence gene profiling and pathogenicity of Streptococcus agalactiae isolated from tilapia farms in Thailand by multiplex PCR[J].J Appl Microbiol,2017,122(6):1497-1507.
[24]BERRIDGE B R,BERCOVIER H,FRELIER P F.Streptococcus agalactiae and Streptococcus difficile 16S-23S intergenic rDNA:genetic homogeneity and species-specific PCR[J].Vet Microbiol,2001,78(2):165-173.
[25]PATTERSON H,SARALAHTI A,PARIKKA M,et al.Adult zebrafish model of bacterial meningitis in Streptococcus agalactiae infection[J].Dev Comp Immunol,2012,38(3):447-455.
[26]KAYANSAMRUAJ P,PIRARAT N,KATAGIRI T,et al.Molecular characterization and virulence gene profiling of pathogenic Streptococcus agalactiae populations from tilapia(Oreochromis sp.)farms in Thailand[J].J Vet Diagn Invest,2014,26(4):488.
[27]GODOY D T,CARVALHOCASTRO G A,LEAL C A,et al.Genetic diversity and new genotyping scheme for fish pathogenic Streptococcus agalactiae[J].Lett Appl Microbiol,2013,57(6):476-483.
[28]UDO E E,BOSWIHI S S,ALSWEIH N.Genotypes and virulence genes in group B Streptococcus isolated in the maternity hospital,Kuwait[J].Med Prin Pract,2013,22(5):453-457.
[29]RAJAGOPAL L.Understanding the regulation of group B streptococcal virulence factors[J].Future Microbiol,2009,4(2):201-221.
[30]EVANS J J,PASNIK D J,KLESIUS P H.Differential pathogenicity of five Streptococcus agalactiae isolates of diverse geographic origin in Nile tilapia(Oreochromis niloticus L.)[J].Aquacult Res,2015,46(10):2374-2381.
[31]祝璟琳,邹芝英,李大宇,等.尼罗罗非鱼无乳链球菌病的病理学研究[J].水产学报,2014,38(11):1937-1944.
[32]ABUSELIANA A F,DAUD H H M,AZIZ S A,et al.Pathogenicity of Streptococcus agalactiae isolated from a fish farm in selangor to juvenile red tilapia(Oreochromis sp.)[J].J Anim Vet Adv,2011,10(7):914-919.
[33]姜建强,额尔敦木图,包花尔,等.嗜酸性粒细胞与寄生虫感染免疫的相关性[J].黑龙江畜牧兽医,2016(2):63-67.
[34]REIMERT C M,FITZSIMMONS C M,JOSEPH S,et al.Eosinophil activity in Schistosoma mansoni infections in vivo and in vitro in relation to plasma cytokine profile pre-and posttreatment with praziquantel[J].Clin Vaccine Immunol,2006,13(5):584-593.
[35]DORAN K S,LIU G Y,NIZET V.Group B streptococcalβ-hemolysin/cytolysin activates neutrophil signaling pathways in brain endothelium and contributes to development of meningitis[J].J Clin Invest,2003,112(5):736-744.
[36]RING A,BRAUN J S,POHL J,et al.Group B streptococcalβ-hemolysin induces mortality and liver injury in experimental sepsis[J].J Infect Dis,2002,185(12):1745-1753.
[37]CHENG Q,CARLSON B,PILLAI S,et al.Antibody against surface-bound C5a peptidase is opsonic and initiates macrophage killing of group B Streptococci[J].Infect Immun,2001,69(4):2302-2308.
[38]BOHNSACK J F,WIDJAJA K,GHAZIZADEH S,et al.A role for C5 and C5a-ase in the acute neutrophil response to group Bstreptococcal infections[J].J Infect Dis,1997,175(4):847-855.
[39]胡会杰,张琪,周明旭,等.不同禽源致病性大肠杆菌毒力基因分布规律研究[J].中国家禽,2015,37(10):34-37.
[40]LIN P Y,LAN R,SINTCHENKO V,et al.Computational bacterial genome-wide analysis of phylogenetic profiles reveals potential virulence genes of Streptococcus agalactiae[J].PloS One,2011,6(4):e17964.
[41]WANG Z,GUO C,XU Y,et al.Two novel functions of hyaluronidase from Streptococcus agalactiae are enhanced intracellular survival and inhibition of proinflammatory cytokine expression[J].Infect Immun,2014,82(6):2615.
[42]BACHRACH G,ZLOTKIN A,HURVITZ A,et al.Recovery of Streptococcus iniae from diseased fish previously vaccinated with a Streptococcus vaccine[J].Appl Environ Micro,2001,67(8):3756.
[43]ALHARBI A H.Phenotypic and genotypic characterization of Streptococcus agalactiae isolated from hybrid tilapia(Oreochromis niloticus×O.aureus)[J].Aquaculture,2016,464:515-520.
[44]ELDAR A,BEJERANO Y,LIVOFF A,et al.Experimental streptococcal meningo-encephalitis in cultured fish[J].Vet Microbiol,1995,43(1):33-40.
(1)农业部渔业渔政管理局.中国渔业统计年鉴[M].北京:中国农业出版社,2018.
