Department of Equine and Small Animal Medicine, Faculty of Veterinary Medicine, University of Helsinki, P.O. Box 57, 00014, Helsinki, Finland.
Department of Virology, Faculty of Medicine, University of Helsinki, P.O. Box 21, 00014, Helsinki, Finland.
Acta Vet Scand. 2020 Jun 3;62(1):26. doi: 10.1186/s13028-020-00525-3.
Streptococcus halichoeri infections have been reported in grey seals, a European badger, a Stellar sea lion and humans, but its presence in companion and fur animals is unknown. Since 2010, S. halichoeri-like bacteria (SHL) have been isolated from fur animals and dogs in Finland. Our aim was to retrospectively investigate laboratory records for SHL from canine and fur animal infections, characterize the isolates and compare their genetic relatedness in relation to three reference strains: CCUG 48324, originating from a grey seal, and strains 67100 and 61265, originally isolated from humans.
A total of 138 and 36 SHLs from canine and fur animal infections, respectively, were identified in the laboratory records. SHL was commonly associated with skin infections, but rarely as the only species. A set of 49 canine and 23 fur animal SHLs were further characterized. MALDI-TOF confirmed them as being S. halichoeri. The growth characteristics were consistent with the original findings, but isolates were catalase positive. In total, 17 distinct API 20 Strep patterns were recorded among all 75 isolates tested, of which pattern 5563100 was the most common (n = 30). Antimicrobial resistance to erythromycin and clindamycin was common in canine isolates, but rare in fur animal isolates. Three clusters were observed by PFGE, and 16S rRNA sequencing revealed 98.1-100% similarities with the human strains and 98.1-99.5% with the seal strain. A phylogenetic tree of concatenated 16S rRNA and rpoB revealed closely related isolates with two clades. Fifteen canine isolates were identical to the human strains based on concatenated 16S rRNA and rpoB sequencing.
Streptococcus halichoeri appears to be quite a common bacterial species in the skin of dogs and fur animals. The clinical significance of S. halichoeri is uncertain, as it was rarely isolated as a monoculture. No apparent temporal or spatial clustering was detected, but isolates from different sources were genetically very similar. Because many canine isolates were genetically similar to the human reference strains, transmission between dogs and humans may be possible. WGS sequencing of strains from different sources is needed to further investigate the epidemiology and virulence of S. halichoeri.
海氏链球菌感染已在灰海豹、欧洲獾、北方海狮和人类中报告，但在伴侣动物和毛皮动物中的存在情况尚不清楚。自 2010 年以来，海氏链球菌样细菌（SHL）已从芬兰的毛皮动物和犬中分离出来。我们的目的是回顾性调查犬和毛皮动物感染的 SHL 的实验室记录，对分离株进行特征描述，并将其遗传相关性与三个参考菌株进行比较：CCUG 48324，源自灰海豹，以及最初从人类分离的菌株 67100 和 61265。
实验室记录中共鉴定出 138 株来自犬的 SHL 和 36 株来自毛皮动物的 SHL。SHL 通常与皮肤感染有关，但很少作为唯一的物种存在。进一步对 49 株犬和 23 株毛皮动物 SHL 进行了特征描述。MALDI-TOF 鉴定证实它们为海氏链球菌。生长特征与最初的发现一致，但分离株为过氧化氢酶阳性。在所有测试的 75 株分离株中，共记录了 17 种不同的 API 20 链球菌模式，其中模式 5563100 最为常见（n=30）。犬分离株对红霉素和克林霉素的耐药性很常见，但在毛皮动物分离株中很少见。PFGE 观察到 3 个聚类，16S rRNA 测序显示与人类菌株的相似度为 98.1-100%，与海豹菌株的相似度为 98.1-99.5%。串联 16S rRNA 和 rpoB 的系统发育树显示密切相关的分离株有两个分支。根据串联 16S rRNA 和 rpoB 测序，15 株犬分离株与人类菌株相同。
海氏链球菌似乎是犬和毛皮动物皮肤中相当常见的细菌物种。由于很少作为单一培养物分离出来，因此海氏链球菌的临床意义尚不确定。未检测到明显的时间或空间聚类，但来自不同来源的分离株在遗传上非常相似。由于许多犬分离株在遗传上与人类参考菌株相似，因此犬与人类之间可能存在传播。需要对来自不同来源的菌株进行 WGS 测序，以进一步研究海氏链球菌的流行病学和毒力。
