Swine erysipelas is an infectious disease caused by Erysipelothrix rhusiopathiae, and the live vaccine strain has been suspected of involvement in the onset of chronic cases. Of the 46 E. rhusiopathiae isolates from cases of chronic (arthritis and endocarditis) or subacute (urticaria) swine erysipelas at an abattoir, 32 were found to be vaccine strains and 14 were wild-type strains. Of the 32 vaccine strains, 5 were derived from cases of endocarditis and urticaria. PCR was used to identify the vaccine strains by detecting the single nucleotide polymorphisms (SNPs) of the vaccine strain. The method was found to be simple with easy judgement of positive and negative results. Sequence analysis of the 432 bp hypervariable region of the SpaA (surface protective antigen A) of the 14 wild-type strains identified two Met-203 type strains (serovar 1a), which are currently prevalent in Japan. The analysis also revealed that nine strains (serovar 2) displaying the same SNPs as the strains isolated in other prefectures, which might warrant further research on the epidemiological relationships between the strains.

Campylobacter fetus is recognized as a causative agent of ruminant abortion, and sepsis and meningitis in humans. This study investigated C. fetus infection status and the mode of pathogen transmission in farms in the Tokachi area of Hokkaido. An epidemiological survey was conducted to determine the prevalence of C. fetus in cattle farms. C. fetus-associated abortion in cattle and carriage of C. fetus in preputial cavities were observed in this area from 2014 to 2016. The bacteria were isolated from the feces of a cow that underwent an abortion, bulls, and a cow and bulls from the same stable. Pulsed-field gel electrophoresis patterns of the isolates were similar to those of isolates from aborted fetus and preputial samples, suggesting that feces played an important role in the transmission and persistence of C. fetus in the investigated farms. All 31 C. fetus isolates were identified as C. fetus subsp. fetus based on 1% glycine tolerance, a key feature of this subspecies, and several recently published molecular methods for C. fetus subspecies identification. However, 7 of the isolates were identified as C. fetus subsp. venerealis using an alternative PCR assay targeting the subspecies-specific gene parA. These results indicate that the PCR assay targeting for parA was not suitable for C. fetus subspecies differentiation in this setting.

An 11-year-old, male, intact Shetland sheepdog, weighting 18 kg, presented with lameness and difficulty standing. The dog was recumbent and developed gas gangrene in the right hind leg. Clostridium novyi was identified by broad-range PCR and sequencing. Gas gangrene and clostridial myositis are rare in dogs. Clostridium perfringens and Clostridium septicum have been identified as causative agents, but C. novyi was never reported.

We observed verrucous endocarditis in the aortic valves of two fattened pigs from different farms in Nagasaki Prefecture, Japan, which were slaughtered in May or August of 2018. In both cases, no bacteria was isolated from the vegetation using 5% sheep blood agar, but DNA of Mycoplasma hyorhinis was detected using PCR. Histopathologically, the vegetation consisted of suppurative necrotizing inflammation with cellular debris, and calcification was also observed in some parts of the lesions. Immunohistochemically, positive reactions for the M. hyorhinis antibody was observed in the vegetation. These two cases of verrucous endocarditis were considered to be caused by M. hyorhinis.