Genetic analysis of <i>Streptococcus equi</i> subsp. <i>equi</i> isolated from horses imported into Japan

Abstract

Strangles is a commonly diagnosed and important infectious disease of equids worldwide, caused by Streptococcus equi subsp. equi . We determined the SeM genotypes of S. equi isolated from imported horses at the Japanese border within the past 8 years, which allowed us to classify 12 strains isolated from these horses from each exporter into four allelic groups. These alleles were different from the alleles of past isolates found in Japan. Furthermore, four strains classified into the same allele were isolated from horses from one exporter over several years. In this study, S. equi isolates from different exporters had different SeM alleles. Attention to the hygiene status of farms will be necessary to prevent the incursion of strangles.

Molecular Features and Antimicrobial Susceptibilities of Streptococcus equi ssp. equi Isolates from Strangles Cases in Indonesia

“…In accordance with this observation, all S. equi equi isolates from this study displayed a mucoid colony morphotype on BAP, indicating that they produced a capsule and could be considered virulent. Virulent strains of S. equi equi almost always have a hyaluronic acid capsule, whereas less virulent strains are non-encapsulated [ 19 , 52 ].…”

“…SeM allele 166 has also been detected in two isolates recovered from horses in the Netherlands in 2013 and Poland in 2017, respectively, which both belonged to ST179 and BAPS-2 as well [ 2 ]. Discrimination of S. equi equi isolates by seM typing has been used to trace strangles outbreaks in Europe [ 21 , 22 , 27 , 53 ], North America [ 23 , 34 ], South America [ 54 ], and Asia [ 52 , 55 ]. Associations between certain seM alleles, geography, and history of horse movements can help to enlighten chains of S. equi equi infection [ 27 , 52 ].…”

“…Discrimination of S. equi equi isolates by seM typing has been used to trace strangles outbreaks in Europe [ 21 , 22 , 27 , 53 ], North America [ 23 , 34 ], South America [ 54 ], and Asia [ 52 , 55 ]. Associations between certain seM alleles, geography, and history of horse movements can help to enlighten chains of S. equi equi infection [ 27 , 52 ]. The number of recognized seM alleles is large and still growing.…”

“…Strangles has been observed in Asian countries before [ 2 ], for example, in United Arab Emirates [ 2 ], India [ 57 ], China [ 55 ], and Japan [ 52 ]. Particularly in South East Asia, strangles outbreaks have been reported occasionally from Thailand [ 58 ], the Philippines [ 59 ], Malaysia [ 60 ], and Indonesia [ 28 , 29 ].…”

SDS-PAGE Profile Analysis of SeM-like Protein of Streptococcus equi subspecies equi.

“…Streptococcus equi subspecies equi is the causative agent of an important, frequently diagnosed infectious disease in equine, which is known as strangles (Kasuya et al, 2019). Although Jordanus Ruffus reported strangles disease in 1251 for the first time, it is still considered as one of the most frequently detected diseases in horses in the world (Ikhuoso et al, 2019).…”