Mycobacterium Flashcards
are mycobacterium aerobic or anaerobic
aerobic
are mycobacterium intracellular or extracellular
facultative intracellular
do mycobacterium form spores
no
what morphology are mycobacterium
rods
are mycobacterium gram positive or negative
positive
have thick peptidoglycan layer and no cell membrane
- does have mycomembrane
are mycobacterium acid-fast positive or negative
positive - have mycotic acid in cell wall
mycobacterium cell wall
lipids, glycolipids, peptidoglycans, mycolic acid
allows for survival within macrophages
increases susceptibility to bacteriophages
how do mycobacterium differ in growth patterns
- speed: slow, rapid, or unable to grow in media
- pigment
- temperature requirement
how do mycobacterium cause disease
tuberculosis, paratuberculosis, granulomatous diseases
can be tuberculous or non-tuberculous
can cause focal or disseminated disease
tuberculosis
chronic granulomatous disease caused by a M. tuberculosis complex
- usually M. tuberculosis and M. bovis
reservoir of tuberculosis
tuberculous individuals
(humans, cattle, wild mammals, chickens, birds)
transmission of tuberculosis
respiratory and ingestion
highest incidence in high density areas
pathogenesis of tuberculosis
- enters through respiratory or oral tract
- replicates locally
- gets taken up by macrophages
- survives and replicates in macrophages
- forms granulomas from cell-mediated immune response
what happens if there fails to be a cell-mediated response
disseminating inflammatory disease throughout the body
need cell response to wall off the mycobacterium in a granuloma
clinical signs of tuberculosis
- rapid progressing but NOT an acute presentation (chronic disease)
- debilitating illness from cytokine release
emaciation, erratic appetite, irregular low fever, enlarged LNs, cough, diarrhea
immunization for tuberculosis
live attenuated vaccine
- induces stronger cell mediated immune response
should be avoided in animals in areas trying to eradicate TB because can cause false positive mycobacterium tests
diagnosis for tuberculosis
sample collection: tracheobronchial or gastric lavage, LN aspirates, urine/feces
- will be acid-fast positive
type IV hypersensitivity test: delayed response to tuberculin injection SQ, conjunctival, or intradermal
- positive test indicates past or present infection
what strain of mycobacterium most commonly causes tuberculosis in ruminants
M. bovis
what strain of mycobacterium most commonly causes tuberculosis in dogs/cats
M. bovis
M. tuberculosis can be anthropozoonotic
what strain of mycobacterium most commonly causes tuberculosis in primates
M tuberculosis: from respiration
M bovis: from ingestion
what strain of mycobacterium most commonly causes tuberculosis in birds
M. avium
Johne’s disease
chronic, irreversible wasting disease in ruminants
caused by M. avium subspecies paratuberculosis
is Johne’s disease reportable
yes
reservoir for Johne’s disease
ruminants and rabbits
symptomatic and asymptomatic, wild and domestic
transmission of Johne’s disease
ingestion or contact with contaminated feces
in utero infection from colostrum or milk
clinical signs of Johne’s disease
chronic weight loss and diarrhea with normal appetite and temperature
progresses to fatality
lesions of Johne’s disease
permanent transverse corrugation of intestinal mucosa
- granulomatous inflammation within lamina propria and submucosa
enlarged LNs
immunization for Johne’s disease
reduces losses but antibodies are not protective
diagnosis of Johne’s disease
sample collection: ileocecal area
- acid-fast positive
- slow growing
molecular diagnosis
- PCR
- faster
atypical mycobacteriosis
chronic wasting condition caused by nontuberculous mycobacteria
mammals, fish, frogs, snakes, turtles
zoonotic - “fish handler’s disease”
