Opportunistic Environmental Yeasts

Question 1

Why is polymorphism important for Candida albicans?

Answer 1

Important virulence determinant. Aids evasion of host defence mechanisms.

Question 2

List 5 clinical conditions in veterinary species which can involve Candida albicans.

Answer 2

Dogs- enteritis, cutaneous lesions
Calves - rumenitis
Mycotic stomatitis- young animals
Gastro-oesophageal ulceration - foals, turkeys, pigs
Buccal, upper GI, crop or cloacal lesions- chicken, gesse, turkeys.

Question 3

What is the ecology of Malassezia pachydermatis?

Answer 3

Inhabit area of skin rich in sebaceous glands. External ear canal, anal region, lips, inter-digital skin. Live on healthy animals - endogenous source. Rarely isolated in environment or on humans.

Question 4

What animals does Malassezia pachydermatis normally live on?

Answer 4

Dogs, cats, ferrets, pigs and rhinos.

Question 5

What is the clinical presentation of Malassezia pachydermatis associated seborrheic dermatitis?

Answer 5

Inflammation and pruritus, greasy matted hair and oily sheen to skin. Marked hyper pigmentation and lichenification (thick and leathery).

Question 6

What is the treatment of Malassezia pachydermatis associated seborrheic dermatitis?

Answer 6

Identify and treat underlying condition if present.
Topical treatment- anti-fungal shampoo.
Systemic treatment if necessary- anti-fungal medications

Question 7

What breeds are predisposed to Malassezia pachydermatis seborrheic dermatitis?

Answer 7

West Highland White Terrier
Shar Pei, Basset Hound, German Shepherd, Cocker Spaniel, Springer Spaniel, Poodle, Australian Silky Terrier, Collies, Shetland Sheepdog, Dachshund.

Question 8

What are the clinical signs of Malassezia pachydermatis associated otis externa?

Answer 8

Dark, pungent discharge from ear, intense pruritis, ear mucosa painful and swollen- they rub ears repeatedly, secondary aural hematomas.

Question 9

What is the treatment of Malassezia pachydermatis associated otis externa?

Answer 9

Identify and treat underlying condition if present. Topical ear preparations containing antifungals. Systemic treatment if necessary- anti-fungal medications.

Chronic cases may require surgery- ablation of ear canal.

Question 10

What is the ecology of Candida albicans?

Answer 10

Normal commensal of the digestive and urogenital tracts in low numbers. Uncommon in the environment.

Question 11

What is the clinical presentation of alimentary and systemic candidiasis?

Answer 11

Cystitis and pyelonephritis, endocarditis, meningitis, septicemia.

Question 12

What is the treatment of alimentary and systemic candidiasis?

Answer 12

Antifungal

Removal if possible of predisposing factors.

Question 13

What is the clinical presentation of Candida associated urogenital conditions?

Answer 13

Genital candidiasis- stallions, bulls
Metritis and vaginitis- mare
Urocystitis- cat
Lower Urinary Tract Infection – Diabetic dogs
Bovine abortion- a rare case or may see reduced fertility.

Question 14

What is the treatment of Candida associated urogenital conditions?

Answer 14

Topical- antifungal antibiotic ointment for oral, genital, mammary.
Clotrimazole infusions for endometritis in mare and cow, bovine mastitis.
Amphotericin B, Flucytosine, Azole Derivatives.

Question 15

What is the clinical presentation of Candida associated bovine mastitis?

Answer 15

Usually a single quarter mastitis.

Question 16

What is the treatment of Candida associated bovine mastitis?

Answer 16

Usually resolves spontaneously. Treatment- intramammary drugs- nystatin, clotrimazole, ketoconazole.

Question 17

What is the cause of Candida associated bovine mastitis?

Answer 17

Contaminated intramammary preparation or heavy environmental contamination.

Question 18

What are Malassezia Pachydermatis?

Answer 18

Commensal, oval, budding yeast, opportunist pathogen.
Lipophilic- predilection for oily areas of sin/ears.
Aerobic and non-fermentative.

Question 19

What are the two main clinical conditions involving Malassezia Pachydermatis?

Answer 19

Seborrhoeic dermatitis and otitis externa.

Question 20

What are three virulence factors of Candida?

Answer 20

1. Surface integrin like molecules- allow binding to matrix proteins and facilitate binding to fibrinogen and complement factors.
2. Proteases and phospholipases- aid tissue invasion.
3. Phenotypic switching and biofilm formation- facilitate evasion of host defenses.

Question 21

What does Amphotericin B antibiotic do?

Answer 21

Affects permeability of cytoplasmic cell membrane.