Mycobacterium

Question 1

Habitat

Answer 1

• Infected host; obligate pathogens

- Environment; facultative pathogens, saprophytes. Quite good resistance, shed by host. Soil, water, surface of plants

Question 2

Morphology

Answer 2

Gram+
Rods, coccoid, branching filaments - variable morphology
Cell structure; cell wall, 3D network formed, mycolic acid -> resistance, lipids, waxes, surface proteins: virulence factors
Species differences

Question 3

Staining

Answer 3

• Gram positive (composition of cell wall makes it hard for staining to diffuse into bacteria)
• Ziehl-Neelsen positive; fuchsin binds to lipids, acid and alcohol fast (resistant)
• Fluorescence dyes - used in human medicine
• Fuchsin as primary stain - can bind to the lipids
• Heat to melt the lipids -> stain can diffuse in

Question 4

Special feature of M. avium subspecies paratuberculosis (Z-N)?

Answer 4

Can be found within the cells of host

Question 5

Culture

Answer 5

• Quite unique
• Obligate aerobic
• Broth: different media, Henley Sauton; produce antigen extract, cord formation, synthetic media, non-natural components
• Solid: egg (kertai, Dorset, Petragnani), serum agar, glycerine potato
• Selective: Petragnani (malachite green), Inoculation after acid or alkaline treatment (slow bacteria replicating, 15min needed - several weeks for culture, usually faster propagation with other bacteria -> use selective media to prevent overgrowth of other bacteria)
• Animal trial (guinea pig, rabbit, pigeon)
• Incubation time, growth characteristics used in diagnostics (species diff.)

Question 6

Culture; M. avium subsp. paratuberculosis

Answer 6

Needs mycobactin -> some genes are missing for cell wall production

Question 7

Cultural differences; incubation time

Answer 7

M. tuberculosis: 3-6 weeks
M. bovis: 4-8 weeks
M. avium subsp. avium: 2-3 weeks
M. avium subsp. paratuberculosis: 6-12 weeks

Question 8

Cultural differences; shape

Answer 8

M. tuberculosis: slender rods
M. bovis: short rods
M. avium subsp. avium: polymorph
M. avium subsp. paratuberculosis: short rods

Question 9

Cultural differences; solid medium

Answer 9

M. tuberculosis: dru colonies
M. bovis: wet colonies
M. avium subsp. avium: cream-like colonies
M. avium subsp. paratuberculosis: wet colonies

Question 10

Cultural differences; broth

Answer 10

M. tuberculosis: thin film
M. bovis: islands
M. avium subsp. avium: thick film, sediment
M. avium subsp. paratuberculosis: thin film

Question 11

Biochemistry

Answer 11

Catalase -

not examined in diagnostic work, molecular methods

Question 12

Antigens

Answer 12

• Complex cell structure
• Glycolipids, lipoproteins -> close relationship of antigens, several shared antigens, cross reactions, immuno-electrophoresis, immunodiffusion
• Tuberculin; old tuberculin filtering the proteins, contained diff antigens, broth culture, boiled, filtered, concentrated. PPD (purified protein derivate); trichloroacetic acid precipitation, proteins ppt -> antigens diagnostic

Question 13

Resistance

Answer 13

Excellent, most resistant among non-spore forming bacteria

Question 14

Pathogenicity

Answer 14

• Obligate pathogens; tuberculosis, paratuberculosis (ruminants)
• Facultative pathogens; mycobacteriosis, mainly disease free
• Saprophytes

Question 15

Which species? see what

Answer 15

• Allocation into species; problems because slow growth, morphology, biochem, genome structure; 16S rRNA examined, pathogenicity
• Genogroups (complexes); 3 main groups, obligate pathogenic. M. tuberculosis-complex, M. acium-complex, M. leprae, M. lepramurium

Question 16

M. tuberculosis complex; M. tuberculosis affecting who

Answer 16

Human, swine, dog, cat, parrot, cattle

Question 17

M. tuberculosis complex; M. africanum

Answer 17

Human, cattle, swine

Question 18

M. tuberculosis complex; M. bovis

Answer 18

Cattle, ruminants, swine, dog, cat, human, BCG - strain used for vaccination in humans

Question 19

M. tuberculosis complex; M. caprae

Answer 19

Cattle, ruminants, swine, dog, cat, human

Question 20

M. tuberculosis complex; M. microti

Answer 20

Rodents, can also affect other spp

Question 21

M. tuberculosis complex; M. pinnipedii

Answer 21

Seal

Question 22

Pathogenic mycobacteria; M. avium subsp. avium

Answer 22

Birds (tuberculosis)

Question 23

Pathogenic mycobacteria; M. avium subsp. paratuberculosis

Answer 23

Cattle, ruminants. Not tuberculosis -> chronic enteritis

Question 24

Pathogenic mycobacteria; M. avium subsp. silvaticum

Answer 24

Birds (tuberculosis), ruminants (paratuberculosis) both birds and Ru

Question 25

Pathogenic mycobacteria; M. avium subsp. hominissus

Answer 25

Swine, human (atypical tuberculosis) -> lesions

Question 26

M. laprae, M. lepramurium;

Answer 26

M. laprae: human (leprosy)

M. lepramurium: mouse, rat, cat, dog (leprosy

Question 27

Facultative pathogens (atypical); swine, cattle

Answer 27

Replicate in the lymphnodes, local lesions, tuberculin reaction (generalized tuberculosis), seldom severe illness

Question 28

Facultative pathogens (atypical); tuberculosis in fishes, reptiles

Answer 28

M. fortuitum, M. marinum.

Cold blooded animals, real tuberculosis

Question 29

Facultative pathogens (atypical); Groups; Photochromogens

Answer 29

• Light is needed for pigment production

- M. kansasii, M. marinum

Question 30

Facultative pathogens (atypical);Groups; Scotochromogens

Answer 30

• Light is not needed for pigment production

- M. scrofulaceum, M gordonae

Question 31

Facultative pathogens (atypical);Groups; Non-chromogenes

Answer 31

• M. intracellulare, M. terrae

Question 32

Facultative pathogens (atypical);Groups; Rapid growers

Answer 32

• Growth within a week (the others approx. 3 weeks)

- M. phlei, M. fortunitum