Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Microbiology > Mycobacteria > Flashcards

Mycobacteria Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q
  • slender, slightly curved or straight rods
  • non-motile, non-spore-forming
  • cell wall has high lipid content (mycolic acid)
  • acid-fast (resist gram stain)
  • aerobic
  • require complex media
  • slow growers (2-6 weeks)
A

Mycobacteria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Mycobacteria media

A

complex media that supresses normal flora and pathogens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Two major Mycobacteria groups

A
  • M. tuberculosis complex

- Nontuberculous mycobacteria (NTMs) or MOTT (Mycobacteria other than tubercle bacillus)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Mycobacterium tuberculosis Complex

A
  • US pathogens: M. tuberculosis, M. bovis

- Other: M. africanum, M. canettii, M. microti, M. leprae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Primary tuberculosis

A
  • transmitted by airborne droplet
  • infect deep lung (alveoli)
  • bacteria phagocytosed and multiply intracellularly
  • T cells sensitize after 4-6 weeks
  • Regression and healing of primary lesion
  • Positive tuberculin skin test
  • Kids: nonproductive cough
  • Adults: small % develop progressive pulmonary disease
  • reactivation can occur
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Reactivation TB

A
  • alteration or suppression of cellular immune system
  • fever, shortness of breath, night sweats, chills, fatigue, etc.
  • 20% asymptomatic
  • eventually productive cough, chest pain
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

M. tuberculosis Complex (clinical diseases)

A
  • Primary tuberculosis
  • Reactivation TB
  • Chronic disease
  • Extrapulmonary TB
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Chronic M. tuberculosis complex disease

A
  • fibrosis
  • calcifications
  • complications (empyema, pleural fibrosis, etc.)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Extrapulmonary TB

A
  • miliary TB (lungs to bloodstream to other organs)
  • mostly in kids and HIV patients
  • Pleural (cough, fever, chest pain)
  • Lymphadenitis
  • Gastrointestinal
  • Skeletal TB of the spine (Pott’s disease)
  • Meningeal (meningitis)
  • Peritoneal
  • Genitourinary TB
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q
  • slow growing
  • raised, dry, rough colonies
  • nonpigmented
  • cord factor
  • grow best at 35-37C
  • positive niacin accumulation
  • reduces nitrate
  • nucleic acid probe available
A

M. tuberculosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Cord factor

A
  • toxic to our cells

- inhibits PMN migration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

TB treatment

A
  • 9 month course of therapy
  • isoniazid and rifampin
  • maybe streptomycin or ethambutol
  • drug combo if resistant
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Mutlidrug-resistant TB

A

second-generation aminoglycosides and fluoroquinolones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Extensively drug-resistant TB

A

drug combos

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

M. bovis

A
  • cattle and humans
  • transmitted via ingestion of contaminated milk or airborne
  • closely resembles TB
  • low rate in US
  • very slow growing
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

NTMs

A
  • soil and water sources
  • opportunistic (lung disease, ICPs)
  • resembles TB, some may be cutaneous
  • no person-to-person transmission
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

M. avium complex (MAC complex)

A
  • M. avium and M. intracellulare
  • most common NTM causing TB in the US
  • slow growing, nonpigmented
  • soil and water sources
  • disease in swine and poultry
  • large increase in number of isolates due to HIV patients developing AIDS (most common systemic disease)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

M. avium complex (biochemical tests)

A
  • inactive in most tests
  • produce heat-stable catalase
  • grow in media containing T2H
  • Nucleic acid probes available to identify
  • treatment based on empiric data, not susceptibility/ID
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Other Slow-growing species

A 
M. paratuberculosis
M. kansasii
M. genavense
M. haemophilum
M. malmoense
M. marinum
M. scrofulaceum
M. simiae
M. szulgai
M. ulcerans
M. xenopi
M. gordonae
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

M. paratuberculosis

A
  • Johne’s disease

- niacin -, nitrate -, tween 80 -

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

M. kansasii

A
  • 2nd most common NTM causing lung disease in US
  • CHRONIC PULMONARY DISEASE
  • occasionally extrapulmonary
  • photochromogenic
  • catalase +, Tween 80 +
  • reduces nitrate
  • pyrazinamidase production
  • nucleic acid probe available
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Slow growing ID

A
  • slow growth with smooth to rough colonies
  • wavy edges and dark centers
  • photoreactivity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Photochromogens

A
  • photoreactivity

- carotene pigment upon exposure to light

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Scotochromogens

A
  • photoreactivity

- produce a pale yellow to orange color in dark or light

25
Q

Non chromogenic

A
  • photoreactivity

- buff or lack of color

26
Q

M. genavense

A
  • disseminated AIDS infection
  • enteritis, genital, soft tissue
  • SQ and heat-stable catalase +, pyrazinamidase +, urease +
27
Q

M. haemophilum

A
  • ICPs
  • submandibular lymphadenitis, subcutaneous nodules, painful swellings, ulcers, abscesses, draining fistulas
  • requires hemoglobin or hemin
28
Q

M. malmoense

A
  • chronic pulmonary disease

- cervical lymphadenitis

29
Q

M. marinum

A
  • cutaneous infections
  • due to contact with saltwater or inadequately chlorinated freshwater
  • “swimming pool granuloma”
30
Q

M. scrofulaceum

A
  • cervical lymphadenitis in kids
  • smooth colonies with dense centers
  • light yellow to deep orange pigment
  • Tween 80 -, don’t reduce nitrate
  • urease +, high SQ catalase
31
Q

M. simiae

A
  • pulmonary disease
  • phochromogenic
  • niacin +
32
Q

M. szulgai

A
  • pulmonary disease
  • similar to TB
  • photochromogenic
  • Tween 80 +, reduces nitrate
  • inhibited by NaCl
33
Q

M. ulcerans

A
  • nodule developing into a severe shallow ulcer
  • nonchromogenic buff colonies
  • heat-stable catalase
34
Q

M. xenopi

A
  • hot and cold-water taps, birds
  • pulmonary infection in patients with predisposing condition
  • scotochromogenic
  • niacin - , reduce nitrate
35
Q

M. gordonae

A
  • tap water and soil sources
  • “tap water” bacillus
  • nucleic acid probe available
36
Q

Rapidly Growing Species

A

M. chelonae
M. fortuitum
M. smegmatis

37
Q

M. chelonae

A
  • M. abscessus group
  • opportunistic
  • more drug resistance than M. fortuitum
  • positive 3-day arylsulfatase test
  • growth on Mac without crystal violet
  • doesn’t reduce nitrate
38
Q

M. fortuitum

A
  • localized infections of skin and soft tissues
  • positive 3-day arylsulfatase test
  • reduces nitrate
39
Q

M. smegmatis

A
  • rare cases of pulmonary, skin, soft tissue and bone infections
  • nonpigmented colonies
  • negative arylsulfatase test
  • reduces nitrate
  • grows on Mac w/o crystal violet
40
Q

M. leprae

A
  • Hansen’s disease (leprosy)
  • Tuberculoid leprosy and Lepromatous leprosy
  • person-to-person transmission
  • low infection rate
  • can’t be cultured in vitro
  • armadillos and foot pads of white mice
41
Q

Tuberculoid leprosy

A
  • skin lesions and nerve involvement

- spontaneous recovery

42
Q

Lepromatous leprosy

A
  • skin lesions

- progressive nerve damage

43
Q

Safety when working with Mycobacteria

A
  • ventilation separate from rest of lab
  • biological safety cabinet
  • disinfectants
  • PPE
44
Q

Mycobacteria specimen collection

A
  • Respiratory specimens
  • sputum (expectorated or induced)
  • early morning specimen on 3 consecutive days (2 out of 3 positive is confirmatory)
  • gastric aspirate, urine, stool, blood, body fluids, tissue
45
Q

Digestion/decontamination of specimens

A
  • liquefy sample through digestion of proteinaceous material
  • allow chemical decontaminating agent to contact and kill the non-mycobacterial organisms
  • mycobacteria survive chemical treatment because of high lipid content in cell walls
  • liquefying mucin allows mycobacteria to utilize nutrients
46
Q

Specimens that need digestion and decontamination

A

sputum, gastric washing, BAL, bronchial washings, transtracheal aspirate

47
Q

Specimens that only need decontamination

A

urine, autopsy tissue, fluids

48
Q

specimens that don’t need digestion and decontamination

A

CSF, pleural fluid, joint fluid

49
Q

Digestion and decontamination agents

A
  • Sodium hydroxide

- N-acetyl-L-cysteine

50
Q

Mycobacteria staining

A
  • irregular uptake of gram stain because of high lipid content
  • light gram-positive if anything
  • ACID-FAST STAINING
  • Auramine-rhodamine fluorochrome stain
51
Q

Acid-fast staining

A
  • Ziehl-Neelsen (uses heat)

- Kinyoun (no heating)

52
Q

Auramine-rhodamine fluorochrome stain

A
  • bright yellow-orange bacilli
  • more sensitive
  • may miss rapid-growers
53
Q

Mycobacteria culture media

A
  • Lowenstein-Jensen (LJ) media (also called ATS): eggs, salts, glycerol, potato flour
  • Middlebrook media
  • all media contain malachite green (suppress gram-positive)
54
Q

BACTEC system

A

amount of labeled CO2 liberated is detected by instrument and is interpreted as “growth index”

55
Q

Mycobacteria Growth Indicator Tube (MGIT)

A

O2 consumption by organism present in the medium are detected as an increase in fluorescence

56
Q

Septi-Chek AFB system

A
  • growth is detected by observing paddle

- detection times shorter than conventional media, longer than BACTEC

57
Q

Mycobacterium ID

A
  • acid fast organism
  • colony morphology (smooth and soft or rough)
  • growth rates: rapid growers (7 days)
  • growth temperature
  • photoreactivity
  • niacin accumulation (most +)
  • nitrate test (M. kansasii and tuberculosis +)
  • catalase (M. tb, bovis are -)
  • Tween 80 hydrolysis
  • iron uptake
  • arylsulfatase test
  • pyrazinamidase (distinguishes M. marinum (+) from kansasii and M. bovis from tb (+))
  • Tellurite reduction (MAC +)
  • urease (M. scrofulaceum (+) and gordonae)
58
Q

Inhibitory tests

A
  • NAP (inhibits M. tb complex)
  • T2H (bovis (S) from tb (R))
  • NaCl tolerance (M. flavescens and M. triviale grow)
  • Growth on MAC agar (M. fortuitum-chelonae complex grow on MAC w/o crystal violet)
59
Q

M. tuberculosis (Identification)

A

MTB is only non-pigmented producer that is nitrate + and niacin + in culture media

Microbiology (26 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions