120. Actinomycoses, nocardioses.

Question 1

Actinomycoses, Nocardiosis Info?

Answer 1

• Diseases caused by Gr+ branching filaments
• Actinomyces & Dermatophilus = fastidious, need blood agar & anaerobic environment to culture
• Nocardia & Rhodococcus = non-fastidious, normal nutrient agar to culture

Question 2

Actinomyces Info?

Answer 2

Diseases caused by Actinomyces spp.

General features of Actinomyces

• Fastidious: cannot propagate themselves in the environment
• Live on surface MMs
• Gr + branching filaments, no spore, no flagella (non-motile), non-acid-fast (Z-N stain - blue)
• • Obligate anaerobic – cannot tolerate oxygen (A. bovis, A. israelii) or facultative anaerobic – can propagate in
• air but also in anaerobic environment (A. viscosus, A. hordeovulneris)
• Actinomycosis: Chronic, purulent, granulomatous, localised, sporadic infection mainly of cattle, swine & dog (human)

History

• Otto Bollinger (1843-1909)
• German pathologist - 1877 - bovine actinomycosis
• James Adolf Israel (1848 – 1926)
• German surgeon - 1878 – human actinomycosis (A. israelii from his name)

Question 3

Pathogenesis of Actinomycoses?

Answer 3

Pathogenesis

• Lesions on skin or MM → invasion → granuloma formation
• Cattle: trauma, rough feed, tooth eruption
• Swine: skin of udder, teats are damaged → lesions: piglets teeth when suckling, floor
• Dog: barley grass awn

Question 4

Clinical & Pathological findings of Actinomycoses?

Answer 4

Clinical & pathological findings

• Cattle lumpy jaw
• Start slowly as a result of the trauma of oral mucosa (rough feed, tooth eruption)
• → chronic rarefying osteomyelitis (several weeks)
• → painless swelling of the affected bones enlarges over a period of several weeks
• → fistulous tracts discharging purulent exudate distorsion of mandibula or maxilla
• → feed intake disorder
• Swine:
• udder actinomycosis → fistulation:
• viscous pus is excreted (A. bovis)
• Pyogranulomatous lesions in the udder
• (Actinobaculum suis cystitis and pyelonephritis: affects the urinary tract of pregnant sows,
• transmitted at coitus 3-4 weeks after mating: anorexia, arching of the back, dysuria, haematuria)
• Dog (Canine actinomycosis):
• Subcutaneous pyogranulomatous lesions, fistulation in the skin
• Extensive fibrovascular proliferation on the pleural surfaces (pleuritis, peritonitis), pericarditis
• Sanguinopurulent exudate in the thorax (reddish)
• Clinical findings: fever, anorexia, respiratory distress (liquid accumulation in the thorax)
• • Human actinomycosis (A. israelii) – granulomatous lesions of the skin + fistulas etc.

Question 5

Diagnosis of Actinomycoses?

Answer 5

Diagnosis

• Chronic lesions (several weeks-months)
• Pathological findings (lesions in mandible/maxilla OR udder)
• Smear: sulphur granules in the pus which contain Gr + filaments
• Yellowish, pinhead-sized (A. bovis)
• Whitish, soft, grey (A. viscosus)
• Differentiation from cattle actinobacillosis
• Sulphur granules: Gr– filaments
• Soft tissues are affected (bones are affected in Actinomyces)
• Bacteriology (anaerobic – blood agar) – isolate the causative agent to determine the AB susceptibility
• A. hordeovulneris – molar tooth/beer cap shaped colonies on blood agar – very characteristic

Question 6

Treatment of Actinomycoses?

Answer 6

Treatment

• Surgery: when lesions are small and circumscribed
• Local disinfectants (Iodine)
• Prolonged therapy with penicillin (streptomycin), OTC, florphenicol or isoniazid for 30 days (dog/human)
• Cattle usually sent to slaughter b/c BW of cattle high for AB use + milk is not useable,
• difficult to eliminate the bacteria from these lesions

Question 7

Prevention of Actinomycoses?

Answer 7

Prevention

• Prevention of scratches or wounds in the skin (invasiveness of bacteria is poor without wounds present)
• Effective wound management
• Beware dry, spiky feed
• Treatment of udder lesions
• Examination of the limbs of dogs in the period when awn is common.

Question 8

Diseases caused by Nocardia?

Answer 8

Diseases caused by Nocardia

• Granulomatous lesions of dogs and cattle, which are sporadic, and have a worldwide distribution
• Tropical and subtropical region: more frequently
• Soil microorganism – live & propagate in the soil
• Gr + Branching filaments → can break down into cocci
• Non-motile (non-flagellated); obligate aerobic (need oxygen for growth)
• Growth on Sabouraud agar (higher glucose content – preferred by fungi) & Nutrient agar: 3-5 days
• incubation time (non-fastidious)
• Wrinkled, pigmented colonies (produce carotenoid pigments – orange); Slightly acid fast (Z-N stain –
• red/pink)

Question 9

Aetiology of Nocardia?

Answer 9

Aetiology

• N. asteroides – most important
• Dog: cutaneous pyogranulomas; pyogranulomatous pleural lesions and pyothorax; generalised
• nocardiosis (Similar to A. hordeovulneris)
• Cattle: chronic purulent, granulomatosis (skin, subcutaneous tissues); chronic mastitis
• N. asteroides, N. brasiliensis – human

Question 10

Canine Nocardiosis?

Answer 10

Canine nocardiosis

• Infection: by inhalation, through skin wounds, by ingestion
• Thoracic form: - same lesions as Actinomycosis
• Fever, anorexia, respiratory distress
• Pericarditis, pleuritis (fibrovascular proliferative reaction on the pleura)
• Sanguinopurulent fluid accumulate in the thoracic cavity
• Cutaneous form: ulcer; granulomatous swelling with discharging fistulous tracts
• Disseminated form: under 1 year of age; fever, purulent bronchopneumonia, abscesses in parenchymal organs

Question 11

Diagnosis of Nocardia?

Answer 11

Question 12

Treatment of Nocardia?

Answer 12

Treatment

• Surgery (when lesions are small)
• Early antibiotic treatment (amikacin, imipenemcilastatin, cotrimoxazole, SXT, linezolid, cefotaxim,
• ceftriaxon)
• Mastitis: intramammary infusion: SXT, cefalosporin, aminoglikoside (5-7 days)
• Min. 6 weeks (1-6 months), human: 6-12 months (especially in immunocompromised patients – HIV)
• For at least 6 weeks

Question 13

Bovine Nocardiosis?

Answer 13

Bovine nocardiosis

• Chronic mastitis – after trauma (soil contaminated catheters)
• Fibrosis: diffuse or multifocal
• White clots in the milk
• Usually sporadic, affecting 1-2 cows in a herd
• Refractory to chemotherapy
• Bovine farcy: chronic infection of superficial lymphatic vessels and lymph nodes.
• Become thickened and cord-like; ulcerating nodules

Question 14

Public health aspects of Nocardia?

Answer 14

Public health aspects

• Soil, infected milk (non-heat treated); Contact with infected dogs – Zoonosis (but in most cases the bacteria
• are acquired from the soil/common sources)
• Cutaneous nocardiosis commonly occurs in immunocompromised hosts (HIV/AIDS, organ transplant etc.)
• Isolate & identify it then determine the susceptibility for AB treatment