Brandt Claudia M, Spellerberg Barbara
Institute of Medical Microbiology and Hospital Hygiene, University Hospital Frankfurt am Main, Johann Wolfgang Goethe University, Frankfurt am Main, Germany.
Clin Infect Dis. 2009 Sep 1;49(5):766-72. doi: 10.1086/605085.
Human streptococci that belong to Streptococcus dysgalactiae subspecies equisimilis (SDSE) have long been known under the name of beta-hemolytic groups C and G streptococci. Extensive taxonomic studies during the past years have distinguished most of the veterinary pathogens belonging to Lancefield groups C and G from those of human origin. After being considered nonpathogenic for many years, SDSE is now recognized as an important bacterial pathogen. The clinical spectrum of diseases caused by this species closely resembles Streptococcus pyogenes infections, including the occurrence of poststreptococcal sequelae. In accordance with these observations, many of the virulence factors present in S. pyogenes can also be found in SDSE strains. High nucleotide-sequence identities in virulence genes and the association of these genes with mobile genetic elements support the hypothesis of extensive horizontal gene-transfer events among streptococcal species of the pyogenic group. Recent epidemiological studies have shown increasing numbers of invasive SDSE infections, often among immunocompromised patients, and suggest that this species will probably gain even more clinical importance in the near future. For a better understanding of the changing epidemiology and pathogenicity of SDSE, an increased awareness of these microorganisms as human pathogens and proper identification are mandatory.
长期以来，属于马链球菌兽疫亚种（SDSE）的人类链球菌一直以β溶血性C组和G组链球菌之名为人所知。在过去几年中，广泛的分类学研究已将大多数属于兰斯菲尔德C组和G组的兽医病原体与人类源病原体区分开来。在被认为多年无致病性之后，SDSE现在被公认为一种重要的细菌病原体。该物种引起的疾病临床谱与化脓性链球菌感染非常相似，包括链球菌感染后后遗症的发生。根据这些观察结果，化脓性链球菌中存在的许多毒力因子在SDSE菌株中也能找到。毒力基因中的高核苷酸序列同一性以及这些基因与可移动遗传元件的关联支持了化脓性菌群链球菌物种间广泛水平基因转移事件的假说。最近的流行病学研究表明，侵袭性SDSE感染的数量不断增加，通常发生在免疫功能低下的患者中，并表明该物种在不久的将来可能会变得更加具有临床重要性。为了更好地了解SDSE不断变化的流行病学和致病性，必须提高对这些作为人类病原体的微生物的认识并进行正确鉴定。
