Bacteriology- Nocardia, Actinomyces, Mycobacterium Flashcards
Motility of listeria
Tumbling at 25 C
Non motile at 37 C
Listeria
1. Flagella
2. Hemolysis shown
3. Infection via?
4. Characteristics
5. Diagnosis
- Peritrichous flagella
- Beta
- Cold contaminated food, dairy. Causes diarrhoea
- Catalase +, Camp +, Cold enrichment at 4 C
- ELISA
Neonatal infection of Listeria is called
Granulomatosis infanti septicum
Treatment of Listeria infection
Ampicillin
Gentamicin
Virulence of M. tb
Cord factor
What is the reason behind acid fastness of M. tb
Mycolic acid
What is the function of LAM in cell wall of M. tb?
It inhibits phagolysosome formation.
LAM can be tested in urine in cases of HIV with TB
Ghon’s focus vs Ghon’s complex vs Ranke’s complex
Ghon’s focus– Lung lesion
Ghon’s complex– Lung + Lymph node
Ranke’s complex– calcified Ghon’s complex
Simon’s focus
Apex involvement of TB
Simmond’s focus
Liver involvement of TB
Assman’s focus
Infraclavicular involvement of TB
Puhl’s
Supraclavicular involvement of TB
Weighert’s focus
Blood vessel involvement of TB
Rich’s focus
Brain involvement of TB
M. TB vs M. bovis
M. Tb is catalase, Niacin, Nitrate reduction positive. M. bovis is negative for all three
M.tb colonies are rough, buff and tough. M. bovis colonies are smooth, white and breaks easily
Sputum sample of M. tb is taken via
Modified Petroff method with 4% NaOH or further modified to NALC with 2% NaOH
ZN stain sensitivity
Lowenstein Jensen Media sensitivity for AFB
ZN: 10^4 AFB/ml
LJ media: 10-100 AFB/ml
Composition of LJ media
Malachite green
Egg
Salt
Asparagine
Newer automated methods for TB detectiom
- Bactec MGIT- Mycobacterium Growth Indicator Tube
It is fluorescent based- uses middlebrook 7H9 broth - BacT/ alert- colorimetry based
- Versatrek- detects pressure changes
Molecular typing methods for TB:
- RFLP using 1S6110 strain
- CBNAAT/ GeneXpert- within 2 hrs. Can detect 131 organism/ ml min
It can also detect resistance (rpoB gene) - Line probe assay
Tests to detect latent TB
- Mantoux: 0.1 ml PPD
- Interferon Gamma Release Assay
IF gamma is needed for granuloma formation. If T lymphocyte sample is exposed to CFP10, TB7.7, ESAT 6–> releases IF gamma which is measured by ELISA
False + Mantoux test
False - Mantoux test
- BCG vaccine, non TB mycobacterium
- HIV, Immunodeficiency
Classification for non TB mycobacteria
Runyon’s classification
Photochromogens
Scotochromogens
Non photochromogens
Rapid growers
Photochromogens Examples
M. marinum
M. kansasii
Scotochromogens examples
M. scrofulaceum
M. gordonae
M. szulgai
Non photochromogens examples
M. avium
M. xenopi
M. ulcerans
‘AUX’
Rapid growers examples in Runyon classification
M. chelonae
M. fortuitum
They grow within 7 days
Which organism causes swimming pool granuloma/ fish tank granuloma?
M. marinum
p/w warty skin lesions
Which are the tap water scotochromogens?
M. gordonae
Which atypical mycobacteria causes Buruli ulcer?
M. ulcerans
M. ulcerans produces an exotoxin called?
Mycolactone exotoxin
What constitutes MAC?
M. avium, M. intracellulare
Lady Windermere syndrome is caused by?
MAC
Which atypical mycobacterium causes post surgery abscess?
M. chelonae
Hansen’s bacillus is
M. leprae
Features of M. leprae
Obligate anerobe
Obligate intracellular- on foot pad of mice or armadillo
MC site of infection of nocardia vs actinomyces
Nocardia- lung. LN absent
Actinomyces- jaw. LN present
MC extrapulmonary site of Nocardia infection
Brain
Molar tooth appearance on solid media is shown by
Actinomyces
Culture of Nocardia is done by
Paraffin bait technique
Tx of Nocardia
Sulfonamides
Tx of Actinomyces
Penicillin
Splendore Hoeppli phenomenon is seen in
Actinomyces
Sporothrix fungi
Which species of Actinomyces is a/w IUD users/ PID?
Actinomyces israellii