Mycobacterium

Question 1

Mycobacterium description

Answer 1

Aerobic & Acid fast! non spore-forming rods, No flagella or capsules, Gram positive but poor at staining

Question 2

What does it mean to be acid fast?

Answer 2

Can bind phenol based dyes and resist discoloration

Question 3

Mycobacterium Major diseases

Answer 3

Tuberculosis - Paratuberculosis - Granulomatous diseases

Question 4

Mycobacterium Virulence factors

Answer 4

Lipids/glycolipids/peptidoglycolipids - Alkyl hydroperoxidase reductase - Sufolipids, phosphatidyl inosital mannoside, surface mycosides, waxes - Glycolipid Dimycolyl trehalose - Mycobactins & exochelins

Question 5

Mycobacterium virulence factors that aid in intramacrophage survival & account for acid-fastness

Answer 5

Lipids, glycolipids, peptidoglycolipids

Question 6

Mycobacterium virulence factors that are responsible for resistance

Answer 6

Alkyl hydroperoxidase reductase

Question 7

Mycobacterium virulence factor - “cord factor”

Answer 7

Dimycolyl trehalose glycolipid

Question 8

Mycobacterium virulence factor for iron acquisition

Answer 8

Mycobactins & Exochelins

Question 9

Tuberculosis - 3 species responsible

Answer 9

Reportable Disease!!!! - M. tuberculosis, M. bovis, M. avium

Question 10

Tuberculosis - Reservoir species of different Mycobacterium species

Answer 10

Humans (M. tuberculosis) - Cattle & wild mammals (M. bovis) - Birds (M. avium)

Question 11

Tuberculosis- Transmission

Answer 11

Mainly inhalation & ingestion - Transplacental, transovarian - intrauterine also possible

Question 12

Tuberculosis Pathogenesis

Answer 12

• Inhalation–> respiratory tract, adjacent lymph nodes & serous cavities - Hematogenous dissemination to liver & kidney - Rare udder infection (zoonotic!!) - Some transplacental to calves (liver & spleen lesions if not aborted)

Question 13

Tuberculosis Disease patterns

Answer 13

Acute exudative process - Neutrophilic - Large infecting dose favored (inhalation) - High virulence - Predisposition of host - Loose tissue architecture (lungs) - Emaciation - Low grade fever - Enlarged lymph nodes - cough - diarrhea (tissue damage from cytokines, help spread organism)

Question 14

What Tuberculosis signs arise after effective cell-mediated immune response?

Answer 14

Localized arrested pulmonary lesions

Question 15

What Tuberculosis signs arise after ineffective cell-mediated immunie response?

Answer 15

Active pulmonary tuberculosis, generalized tuberculosis

Question 16

Tuberculosis in ruminants - causative species

Answer 16

M. bovis!! sometimes avium/tuberculosis

Question 17

Tuberculosis in ruminants- Disease pattern

Answer 17

Granulomatous lesions all over lungs, serous cavity surfaces! -

Question 18

Tuberculosis in horses

Answer 18

M. avium - Rare - GI infection, pharynx & intestine, maybe lungs, spleen & serous membranes

Question 19

Tuberculosis in pigs

Answer 19

M. bovis & avium - GI, Miliary lesions in liver & spleen

Question 20

Tuberculosis species in Dogs & Cats

Answer 20

Mainly M. bovis

Question 21

When I say Marie’s Disease, you say…

Answer 21

Dog tuberculosis - M. bovis

Question 22

Tuberculosis in dogs

Answer 22

Marie’s Disease - Hypertrophic pulmonary osteoarthropathy

Question 23

Tuberculosis in cats

Answer 23

Intestinal & abdominal localization, ulcerative skin lesions

Question 24

Tuberculosis in birds

Answer 24

M. avium complex - Grows @ higher temp - Alimentary infection–> disseminate to liver & spleen. Transovarian infection to chicks rare

Question 25

Tuberculosis in foals! and DDx for gram positive, aerobic bacteria causing pneumonia

Answer 25

Rare! DDx : Rhodococcus equi

Question 26

Tuberculosis species in primates

Answer 26

M. bovis (mainly) M. tuberculosis, M avium & non-tuberculous mycobacteria in immunosuppressed

Question 27

M. tuberculosis in primates

Answer 27

Airborne route, mostly respiratory tract infections

Question 28

M. bovis in primates

Answer 28

Ingestion, unpasteurized milk!!

Question 29

Case Study - Nasty picture of gross growth on vet surgeons finger

Answer 29

Verrucose lesion of cutaneous tuberculosis

Question 30

Tuberculosis breed resistance

Answer 30

Zebu cattle (with hump) more resistant than other breeds.

Question 31

Tuberculosis vaccine>

Answer 31

Available - Temporary immunity & hypersensitivity in humans - Interferes with interpretation of testing so ONLY for eradicated places

Question 32

Mycobacterium avium subspecies

Answer 32

4 subspecies (avium, paratuberculosis, silvaticum, hominissuis)

Question 33

When I say Johne's disease, you say...

Answer 33

Mycobacterium avium paratuberculosis!

Question 34

When I say transverse corrugation of intestinal mucosa of ruminants, you say...

Answer 34

Johne's Disease! Mycobacterium avium paratuberculosis!

Question 35

M. avium paratuberculosis

Answer 35

Johne's Disease! Chronic, irreversible wasting disease. **REPORTABLE**

Question 36

M. avium paratuberculosis - species affected

Answer 36

Symptomatic/asymptomatic in wild & domestic ruminants, swine & rabbits

Question 37

M. avium paratuberculosis transmission

Answer 37

Ingestion - contact with fecally-contaminated materials (in utero or colostrum ingestion also possible

Question 38

Johne's Disease pathogenesis

Answer 38

Cell mediated immune phenomena (12 mo incubation pd) --> survive & replicate inside M cells** --> macrophages release cytokines--> TH1 recruited (tuberculoid stage) --> IFN-g compromised, fails to eliminate bacteria --> Progressive granulomatous reaction (TH2 recruitment) --> sloughing of mucosal epithelium=lepromatous stage

Question 39

Johne's Disease pathogenesis Lepromatous stage

Answer 39

TH2 recruitement - Sloughing of mucosal epithelium

Question 40

Johne's Disease pathogenesis Tuberculoid stage

Answer 40

TH1 recruitment

Question 41

Johne's Disease in ruminants

Answer 41

Chronic weight loss, diarrhea, permanent transverse corrugation of intestinal mucosa - Enlarged draining lymph nodes w/ macrophages w/bacteria

Question 42

Johne's Disease - breeds especially susceptible

Answer 42

Guernsey, Shorthorn, Jersey

Question 43

Johne's Disease When disease most occurs

Answer 43

In young - Domestication/captivity - Stress, crowding, shipment etc

Question 44

Johne's Disease Dx

Answer 44

Intradermal test - can be messed up with vaccination

Question 45

Feline leprosy - causative agent & description

Answer 45

M. lepraemurium - chronic noduloulcerative nonTB mycobacterial infection of skin - Transmission by rodent bite - Poor prognosis

Question 46

M. lepraemurium description

Answer 46

Acid fast agent, very fastidious (picky about growth medium)

Question 47

Canine Leproid Granuloma Syndrome

Answer 47

Uncultured, saprophytic mycobacterium - Numerous acid-fast organisms - Condition of subcutis & skin of pinnae, face, body extremities

Question 48

Ulcerative dermatitis of cats & dogs - Causative agents

Answer 48

M. fortuitum, M. chelonae, & others

Question 49

Ulcerative dermatitis of cats & dogs - Description

Answer 49

Chronic, non-healing skin lesions, months to years - Pyogranulomatous inflammation - poor-staining organisms

Question 50

Bovine Farcy

Answer 50

Bovine Mycobacterial Ulcerative Lymphangitis - Nodular-ulcerative skin lesions of lower extremitis & ventral trunk - May cause false positive tuberculin reactivity

Question 51

Bovine Farcy causative agents

Answer 51

M. farcinogenes, M. senegalenses (and Nocardia farcinca)

Question 52

Mycobacterium in aquatics

Answer 52

Zoonotic significance - "swimming pool granuloma" or "fish handler's disease"