Hedegaard L, Christensen H, Chadfield M S, Christensen J P, Bisgaard M
Department of Veterinary Pathobiology, University of Copenhagen, Faculty of Life Sciences, Stigbøjlen 4, Frederiksberg C, Denmark.
Avian Pathol. 2009 Apr;38(2):155-60. doi: 10.1080/03079450902737763.
The genus Streptococcus consists of more than 60 species, but only Streptococcus equi subspecies zooepidemicus, Streptococcus gallolyticus ssp. gallolyticus, Streptococcus gallinaceus, Streptococcus dysgalactiae, Streptococcus mutans and Streptococcus suis have been isolated from poultry. During investigations of the aetiology of increased mortality in broiler parent stock at the end of production, pure cultures of streptococcal-like organisms that could not be classified among these six species were obtained from 24 cases of septicaemia or valvular endocarditis and septicaemia. Phenotypic characterization using the API20 STREP kit identified the isolates as Aerococcus viridans (10), Aerococcus urinae (2), Leuconostoc species (4), Streptococcus salivarius (2), Streptococcus bovis II 3 (1), Enterococcus avium (3), Enterococcus faecium (1) or Gemella morbillorum (1). However, this identification was misleading as subsequent genetic investigations using pulse field gel electrophoresis and sequencing of 16S rRNA genes showed that 19 isolates were classified as Streptococcus pluranimalium, while the remaining isolates were E. avium (3), E. faecium (1) or Lactobacillus species (1). Misidentification by API20 STREP was related to the database provided by the manufacturer, as the phenotypic characteristics could identify these organisms as S. pluranimalium. The isolates of S. pluranimalium belonged to at least three different clones as determined by pulsed field gel electrophoresis of SmaI-digested genomic DNA. The capacity that these isolates had to colonize the valvular endothelium was suggested by the occurrence of valvular endocarditis in 12 of 19 cases. Demonstration of the same clone in all four houses on a farm suggested the pathogenic potential of this organism.
链球菌属由60多个菌种组成，但仅从家禽中分离出了马链球菌兽疫亚种、解没食子酸链球菌解没食子酸亚种、鸡链球菌、停乳链球菌、变形链球菌和猪链球菌。在对产蛋后期肉种鸡死亡率上升的病因进行调查期间，从24例败血症或心内膜炎合并败血症病例中获得了无法归类于这六个菌种的类链球菌纯培养物。使用API20 STREP试剂盒进行表型鉴定，将分离株鉴定为绿色气球菌（10株）、尿液气球菌（2株）、明串珠菌属（4株）、唾液链球菌（2株）、牛链球菌II 3（1株）、鸟肠球菌（3株）、粪肠球菌（1株）或麻疹孪生球菌（1株）。然而，这种鉴定具有误导性，因为随后使用脉冲场凝胶电泳和16S rRNA基因测序进行的基因研究表明，19株分离株被归类为多动物源链球菌，其余分离株为鸟肠球菌（3株）、粪肠球菌（1株）或乳杆菌属（1株）。API20 STREP的错误鉴定与制造商提供的数据库有关，因为表型特征可将这些微生物鉴定为多动物源链球菌。通过对经SmaI消化的基因组DNA进行脉冲场凝胶电泳确定，多动物源链球菌的分离株至少属于三个不同的克隆。19例中有12例发生心内膜炎，提示这些分离株具有定植于瓣膜内皮的能力。在一个养殖场的所有四个鸡舍中都检测到相同的克隆，表明该微生物具有致病潜力。
