Mycobacterium Flashcards
Genus Mycobacteria
Ubiquitous, rod shaped, non motile, non spore forming
Non capsulated and resist decolorization
Cell walls have mycolic acid and acid-fast bacilli
What does mycolic acid do?
Inhibits uptake of nutrients into bacterial cell
Causes cell to clump
The generation or doubling time for M tuberculosis is __________
18-24 hours
Mycobacterium growth
Löwenstein-Jensen medium
Readily killed by heat (pasteurization)
Resistant to chemical change and drying
Most mycobacteria are _________
Non pathogenic (soil and water organisms)
M. Tuberculosis transmission
Humans tuberculosis (TB)
From milk without proper pasteurization, human to human (resp. aerosols)
M. Tuberculosis Epidemiology
1/3 world pop carries (not infections but (TB+)
8 mill cases / year
3 mill deaths/ year
M. Tuberculosis Pathogenesis
Chronic infectious disease
Inhaling droplet with tubercle bacilli
Resist macrophages and multiply intracellularly
Tubercle bacilli size significance
Because they’re small, they’re airborne for long periods of time —> ingestion
Mycobacterium Bovis
Live attenuated bovine strain
Media is Bacille-Calmette-Guerin
Used to immunize humans
How does M. Bovis affect cattle?
Affects respiratory tract + adjacent LNs
Hematogenous dissemination with liver and kidneys
Uterus= fetal infection
Abortion (less than 2%)
Clinical signs of M. Bovis
Lesion in lung
Infection of udder
Contaminated milk
Coughing and sneezing
M. Bovis spread
Contaminated feed, aerosol form other cattle
M. avium spp. avium
Poultry infections via alimentary canal, disseminate to liver and spleen
Psittacine resistant but susceptible
Dogs and cats with mycobacteria
Infected with M. Bovis
Dogs susceptible to M. Tuberculosis
Horses with mycobacterium
Rarely infected but more with M. Avium ssp. Hominissuis
Primates infected with My bacterium
Susceptible to M. Tuberculosis than M. Bovis. Resistant to M. Avium
Diagnosis of mycobacterium
Ziehl- Neelsen/ acid-fast stain
Smear with red stain carbon-fuschin
Counter stain with methylene blue
Cold stain modification for mycobacterium diagnosis
The carbol-fuschin first dissolved in detergent
TB skin test (Mantoux tuberculin test)
Intradermal injection Of Ags
Human: Purified protein derivative
Cattle: comparative Intradermal tuberculin
Tuberculin testing sites
Human: inner arm
Bovine: skin of caudal folds
Swine: skin of ear
Avian: wattles (swelling +)
Treatment for Mycobacteria
First-line and second-line drugs
Prophylactic treatment with isoniazid for pets
Mycobacteria control/ prevention in cattle
ID and elimination of infected
No BCG vx in low prevalent situations
Distinguish infected from vaccinated
M. Avium spp. paratuberculosis (MAP)
Broad host range, high degree of tropism
Causes chorionic enteritis and chronic granulomatous disease
Paratuberculosis
Chronic inflammation of intestine caused by M . Paratuberculosis
Chron’s disease in humans
Johne’s disease of ruminants
Where is M. Avium spp. paratuberculosis (MAP) found?
Isolated from gut/ feces
In milk, feces, and meat of infected cattle
In water supplies with infected cattle feces
What is MAP resistant to?
Standard food processing techniques (pasteurization and cooking)
Standard water treatment methods
Clincal symptoms of MAP
Emaciation
Unresponsive to dewormers and antibiotics
Profuse water diarrhea (cattle)
Intermandibular edema
Differential diagnosis of paratuberculosis
Intestinal parasitism, chronic malnutrition, caseous lymphadentitis, ovine progressive pneumonia, environmental toxins, cancer
Johne’s disease public health
Most serious disease affecting cattle industry
Difficult to recognize, control and treat
Increased milk contamination
Diagnostic tests for MAP
Culture of feces
8-24 weeks incubation
Blood tests, ELISA, acid-fast staining of intestinal mucosa
PCR
Leprosy
M. Leprae (human)
M. Lepraemurium (rodent)
More common in tropical countries
Not highly contagious
How is leprosy transmitted
When exudate of mucous membrane lesions and skin ulcers reach broken skin
Young children and males susceptible
