Chapt 26 Mycobacteria

Question 0

Photochromogenic

Answer 0

Characteristic appearance of Mycobacterium spp. in which exposure to light stimulates pigment production

Question 1

Acid-fastness

Answer 1

Ability of bacteria, such as the Mycobacterium spp., to retain dye when treated with mineral acid or an acid-alcohol solution

Question 2

Scotochromogenic

Answer 2

Mycobacterium spp., produces pigment in either light or dark growth requirements

Question 3

Nonphotochromogen

Answer 3

Mycobacterium spp., such as M. tuberculosis, that don’t produce pigmentation

Question 4

Purified Protein Derivative (PPD)

Answer 4

Diagnostic skin test for tuberculosis

Question 5

Endogenous

Answer 5

Originating from within an organism

Question 6

Leprosy

Answer 6

Infection of the skin, mucous membranes, & peripheral nerves caused by Mycobacterium leprae

Question 7

Lowenstein-Jenson agar

Answer 7

Non-selective media for the isolation of Mycobacteria
Nutrients: eggs, potato, flour, glycerol
Inhibitors: malachite green

Question 8

Middlebrook agar

Answer 8

Non-selective media for the isolation of Mycobacteria
Nutrients: Oleic acid, albumin
Inhibitors: Malachite green

Question 9

Kinyon stain

Answer 9

Procedure often used for acid-fast staining, like Ziehl-Neelson stain, a carbol-fuchsin method; thought does not involve heat application

Question 10

Mycobacterium genus

Answer 10

Branching, filamentous, straight-curved rods, aerobic, DON’T stain w/ Gram stain, Acid Fast Bacilli (AFB), cell walls have high lipid content, needs Acid Fast Stain, ubiquitous (present in soil & water); normal flora, opportunistic, and true pathogens

Question 11

Mycobacteria cultures

Answer 11

Airborne pathogens require BSL3 processing & testing, special enriched/selective media in sealed screw top tubes, separate incubators with lights, and prolonged incubation, generally incubated for 8 wks

Question 12

Slow growers

Answer 12

Visible colonies in >7 days

Question 13

Rapid growers

Answer 13

Visible colonies in <7 days

Question 14

Special growers

Answer 14

Will not grow in vitro

Question 15

Acid Fast Stain

Answer 15

1-Primary Stain 2-Decolorizer 3-Counter Stain

Question 16

MOTT

Answer 16

Mycobacteria Other Than Tuberculosis

Question 17

Mycobacterium tuberculosis

Answer 17

TB…consumption…Koch’s bacillus, slow groweres 3-6 wks for visible colonies, complex nutritional & increased CO2 requirements, dry-buff tan colored colonies, very prolonged chronic, ultimately fatal respiratory infections, weight loss, night sweats, fatigue, bloody sputum, acquired from aerosols & possible dissemination, PMNs+Monocytes phagocytize organism, forming characteristic exudate lesions (tubercles)

Question 18

M. tuberculosis biochemical tests?

Answer 18

Niacin (+) Nitrate (+)

Question 19

M. tuberculosis treatment?

Answer 19

An initial 2-mos phase of four drugs: Isoniazid, Rifampin, Pyrazinamide, & Ethambutol, followed by a 4-mos continuation phase of Isoniazid & Rifampin
Strict adherance to treatment is critical, antibiotic resistance is increasing, MDR-TB (Multi-drug resistant TB)

Question 20

PPD of >5mm

Answer 20

(+) for high risk patients (HIV)

Question 21

PPD of >10mm?

Answer 21

(+) for high risk of progression (healthcare)

Question 22

PPD of >15mm?

Answer 22

(+) for patients with no known risk

Question 23

Mycobacteria leprae

Answer 23

Causative agent of leprosy (Hansen’s Disease), 150 US cases per yr (most acquired over seas), weak pathogen…95% human immune, stains as parallel bundles of organisms of AFB stains, infects skin, mucous membranes, & cartilaginous tissue, effective antibiotic treatment, Armadillo (15%) is the only animal, besides humans that is known to carry leprosy, will not grow in vitro, armadillo food pads used for in vivo cultures

Question 24

M. kansasii

Answer 24

Photochromogen, pulmonary infections in southern US

Question 25

M. gordonae

Answer 25

Scotochromogen, “tap water” usually a contaminant

Question 26

M. marinum

Answer 26

Photochromogen, water related cutaneous infections

Question 27

M. scrofulaceum

Answer 27

Scotochromogen, childhood cervical lymphadenitis

Question 28

M. fortuitum

Answer 28

Rapid grower, localized skin infections

Question 29

M. chelonei

Answer 29

Rapid Grower, disseminated cutaneous infections