Atypical multibacterial granulomatous myositis in a horse: First report in Italy

Claudia Rifici, Anna Rita Attili, Davide De Biase, Roselane Gonçalves Dos Santos, Núbia Seyffert, Thiago Luiz De Paula Castro, Henrique Cesar Pereira Figueiredo, Carmelo Scaramozzino, Stefano Reale, Orlando Paciello, Vincenzo Cuteri, Sharon Jane Spier, Vasco Azevedo, Giuseppe Mazzullo

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


Infectious causes of myositis are reported relatively uncommonly in horses. Among them, bacterial causes include Streptococcus equi subsp. zooepidemicus, Actinobacillus equuli, Fusobacterium spp. Staphylococcus spp, and Corynebacterium pseudotuberculosis. Infection can be spread to muscles via haematogenous or extension from skin lesions. Parasitic myositis has also been documented. In this report, a 12 year-old Italian Quarter Horse mare presented with diffuse subcutaneous nodules and masses ranging from 2 × 3 to 5 × 20 cm in size, and adherent to subcutis and muscles that were first macroscopically and cytologically diagnosed as pyogranulomas. Subsequently, histological, molecular, bacteriological, and biochemical investigations were performed. All the data obtained allowed to diagnose a severe and diffuse multibacterial granulomatous myositis caused by Corynebacterium pseudotuberculosis and Corynebacterium amycolatum. Following the therapy and an initial disappearance of most of the lesions together with a general improvement of the mare, the clinical condition deteriorated, and new nodules appeared. Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) and PCR techniques revealed the presence of bacteria as Glutamicibacter creatinolyticus and Dietzia spp. To the authors’ knowledge, this case report represents the first description of multibacterial granulomatous myositis due to Corynebacterium pseudotuberculosis, Corynebacterium amycolatum, Glutamicibacter creatinolyticus, and Dietzia spp. in a horse reared in Italy.

Original languageEnglish (US)
Article number47
Pages (from-to)1-11
Number of pages11
JournalVeterinary Sciences
Issue number2
StatePublished - Jun 2020


  • Bacterial myositis
  • Corynebacterium pseudotuberculosis
  • Dietzia spp
  • Glutamicibacter creatinolyticus
  • Horses

ASJC Scopus subject areas

  • veterinary(all)


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