Morimoto Misako, Kato Atsushi, Kojima Hiroe, Akaike Yuta, Nogami Kotoe, Sasakawa Chihiro, Nagai Shinya, To Ho
Nippon Institute for Biological Science, 9-2221-1 Shin-machi, Ome, Tokyo, 198-0024, Japan.
Biomedical Science Association, 2-20-8-3F Kamiosaki, Shinagawa-ku, Tokyo, 141-0021, Japan.
Curr Microbiol. 2021 Jan;78(1):55-66. doi: 10.1007/s00284-020-02254-2. Epub 2020 Nov 3.
Erysipelothrix rhusiopathiae causes swine erysipelas (SE), which results in considerable economic loss on pig farms. During SE outbreaks that occurred sporadically from 2008 to 2011 in Japan, new E. rhusiopathiae strains were isolated with a specific surface protective antigen (Spa)A protein characterized by methionine at position 203 and isoleucine at position 257 (M203/I257 SpaA type). To determine whether strains with the M203/I257 SpaA type are still prevalent in Japan, we collected 79 strains of E. rhusiopathiae from pigs showing various SE symptoms from 2012 to 2019 and classified them based on serovar typing, spaA gene sequence analysis, and lineage typing. We found that the majority of recent E. rhusiopathiae strains (59/79) belonged to the serovar 1a strain, and that the M203/I257 SpaA type (56/59) was predominant continuing from 2008 to 2011. Furthermore, serovar 1a strains with IVb-1 and IVb-2 lineages that had been isolated in specific regions of Japan were no longer local but were found across Japan. The pathogenicity of recent isolates tested in mice was not significantly changed when compared to that of previously isolated strains. Our results suggest that recent SE outbreaks were not due to changes in the SpaA protein or to altered virulence of E. rhusiopathiae but were rather caused by the persistent presence of E. rhusiopathiae with the M203/I257 SpaA type.
猪红斑丹毒丝菌可引发猪丹毒(SE),给养猪场造成巨大经济损失。在2008年至2011年日本零星发生的猪丹毒疫情期间,分离出了新型猪红斑丹毒丝菌菌株,其具有一种特定的表面保护性抗原(Spa)A蛋白,该蛋白在第203位为甲硫氨酸,在第257位为异亮氨酸(M203/I257 SpaA型)。为确定M203/I257 SpaA型菌株在日本是否仍然流行,我们于2012年至2019年从出现各种猪丹毒症状的猪身上收集了79株猪红斑丹毒丝菌,并根据血清型分型、spaA基因序列分析和谱系分型对它们进行了分类。我们发现,近期的大多数猪红斑丹毒丝菌菌株(59/79)属于血清型1a菌株,并且M203/I257 SpaA型(56/59)从2008年到2011年一直占主导地位。此外,在日本特定地区分离出的具有IVb-1和IVb-2谱系的血清型1a菌株不再局限于当地,而是在日本各地都有发现。与先前分离的菌株相比,近期在小鼠身上测试的分离株的致病性没有显著变化。我们的结果表明,近期的猪丹毒疫情并非由于SpaA蛋白的变化或猪红斑丹毒丝菌毒力的改变,而是由具有M203/I257 SpaA型的猪红斑丹毒丝菌持续存在所致。