chapter 36 Nocardiosis and Actinomycosis............................
DEFINITION/OVERVIEW
Nocardiaspp. andActinomycesspp.: uncommon pyogranulomatous and suppurative
infection; dogs and cats.
Opportunistic organism; enters body through contamination of wounds, respiratory
inhalation, or ingestion.
ETIOLOGY/PATHOPHYSIOLOGY
Nocardia
Nocardiaspp. are aerobic, filamentous, gram-positive, partially acid-fast, branching
soil saprophytes.
Immunocompromise appears to be a significant predisposing factor for development
ofNocardiainfection.
Causes three syndromes: localized cutaneous/subcutaneous; pulmonary; systemic/
disseminated.
Systems affected: respiratory, skin/exocrine, lymphatic, musculoskeletal, nervous.
Nocardia asteroidescomplex.
N. brasiliensis.
N. nova(main species affecting cats).
N. farcinica.
N. otitidiscaviarum.
Actinomyces
Actinomycesspp. are anaerobic, filamentous, gram-positive, nonacid-fast, branching
commensals in the oral cavity and bowel.
Infection may have a latency period up to 2 years post exposure or trauma.
Most often causes a subcutaneous swelling; less commonly causes osteomyelitis or
pulmonary/pleural infection.
Blackwell’s Five-Minute Veterinary Consult Clinical Companion: Small Animal Dermatology, Third Edition.
Karen Helton Rhodes and Alexander H. Werner.
©2018 John Wiley & Sons, Inc. Published 2018 by John Wiley & Sons, Inc.
535