American foulbrood is the most destructive honeybee bacterial disease. The etiological agent, Paenibacillus larvae, has been classified into four genotypes by a repetitive-element PCR (ERIC I-IV) and 21 sequence types by multilocus sequence typing (ST1-21). In this study, we genotyped Japanese P. larvae isolates for the first time and revealed the presence of three genotypes (ERIC I-ST2, ERIC I-ST15 and ERIC II-ST10) in the western region of Aichi prefecture. ERIC I-ST15 and ERIC II-ST10 are globally distributed types, whereas the ERIC I-ST2 isolate was the first isolate of this genotype identified outside the native range of the European honeybee. The ERIC I and II isolates differed in phenotypes including cell morphology, and these may be useful for predicting ERIC types.

A 14-month-old Japanese black beef steer presented with severe chronic diarrhea and emaciation and was euthanized. Postmortem examination showed thickened and corrugated intestinal mucosa and enlarged granulomatous mesenteric lymph nodes with caseating necrosis. Numerous epithelioid cells and multinucleated giant cells infiltrated in the lamina propria and the submucosal tissue of the intestines. These cells were also observed in the systemic organs. Many acid-fast bacilli were detected in the cytoplasm of these cells and were identified as ‘Mycobacterium avium subsp. hominissuis’ (Mah) on the basis of the results of molecular examinations and immunohistochemistry. These findings indicate that Mah can cause systemic mycobacteriosis, and this unique infection needs to be distinguished from Johne’s disease and tuberculosis in cattle.

A 7-day-old calf died following development of mild respiratory symptoms. Postmortem examination revealed the kidneys were inflamed, and Gram-negative bacteria was detected in the kidneys, supporting the diagnosis of suppurative pyelonephritis. Mannheimia varigena antigen was found in the lesions and the cytoplasm of macrophages and neutrophils in the renal cortex. The Gram-negative bacilli from the kidney were identified as M. varigena by sequencing the 16S rDNA. Although M. varigena is known to cause bovine respiratory disease syndrome, shipping fever, and meningitis, it was unknown that it could also cause suppurative pyelonephritis. Our study provides the first evidence of suppurative pyelonephritis caused by M. varigena in cattle and information that would improve our understanding, diagnosis, and treatment for M. varigena infections.

Five-day-old neonatal piglets presented with debilitation and ananastasia. At the necropsy of one piglet, the apex of the tongue was found to be discolored dark red, and disseminated white foci were found on the cut surface. Many white foci were also found in the lungs and on the serosa of the liver and spleen. Histopathological findings revealed multifocal necrotic glossitis and pneumonia with Gram-negative bacilli. The bacilli were identified as Actinobacillus suis through immunohistochemical, biochemical, and genetic tests, including 16S rRNA gene sequencing. Although A. suis usually causes inflammation in thoracic and abdominal organs, lesions were also found in the tongue in the present case. This study is the first report of glossitis caused by A. suis .

A 5-month-old crossbred beef steer died after exhibiting astasia. A postmortem examination revealed verrucous endocarditis and numerous renal hemorrhages. Gram-positive bacteria were identified in the necrotic lesions of the verruca and mitral valve via histopathological analysis. Multifocal necrosis and hemorrhage were detected in the renal cortex. Gram-positive cocci isolated from the verruca were identified via biochemical tests and 16S rRNA gene sequence analysis as Streptococcus suis. Serotyping indicated that the S. suis isolates were untypable, following which these isolates were classified as a new sequence type (ST1000) via multi-locus sequence typing. S. suis is an important pathogen of pigs. However, clinical cases in cattle are rare. This report is intended to provide information that may be useful in the diagnosis of streptococcal disease in cattle.

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