Mycology/Mycobacteriology Flashcards
What 3 components are typical of fungal cell wall?
1-Mannan
2-Glucan
3-Chitin
Single cells that grow in a creamy mucoid colony and are facultative anaerobes are what?
Yeast
Multicellular filamentous (hyphae and mycelium) fuzzy colonies that are obligate aerobes are likely what?
Mold
Ture hyphae or germ tubes are __________ whereas pseudohyphea are ________ tubes.
continuous, segmented
Hyphae with dark lines delineating each segment are called?
Septate hypha (aspergillus sp.)
What are the two kinds of reproduction?
- Asexual/anamorph (budding or conidia)
- Sexual/teleomorph (spores possible)
Fungi that are a mold at one temp (25-30 C) and yeast at another (35-37 C) are called what?
Dimorphic fungi
What are the 3 main groups of pathogenic fungi?
1-Dimorphic
2-opportunistic
3-cutaneous
What are two important opportunistic fungi?
- Candida Spp
- Rhizopus Spp
What are 5 risk factors for fungal infections?
1-Immunocompromised
2-Premature infants
3-Critically ill/hospitalized
4-Travelers and residents of endemic areas
5-Direct contact with animals/infected materials
What are the 3 common methods for direct specimen diagnostic testing?
1-Direct microscopy
2-Culture
3-Histopathology
What are the advantages and disadvantages of Direct microscopy diagnosis?
- Fast and cheap
- Insensitive
What are the advantages and disadvantages of Culture diagnosis?
- Gold standard from sterile body site
- Allows genus/species level of ID
- Delayed results
- Difficult to obtain
- insensitive
What are the advantages and disadvantages for histopathology diagnosis?
-Gold standard for invasive disease
- Difficult to obtain
- not species specific
What are two current methods for identification starting with a pure culture?
1-Proteomic identification (MALDI)
2-Targeted gene sequencing
What are the two most common Candida species?
C. Albicans
C. Glabrata
What are three most common species that cause mucormycosis?
1-Mucor
2-Rhizopus
3-Rhizomucor
*Thrive in high glucose and acidic environment
Bacilli that are obligate aerobes with mycolic acid in their cell wall are called what?
Mycobacteria
*cell wall is high lipid and is waxy
What is the most common/important mycolic acid in mycobacteria?
lipoarabinomannan
What stain involves binding carbol fuchsin dye that is resistant to decolorization by acid?
Acid Fast Bacilli (AFB)
*M. Tuberculosis
What are the three most common mycobacteria?
1-M. Tuberculosis
2-M. Bovis
3-M Bovis Baville calmette-Guerin (BCG)
What is an example of a special grower? One that cannot be grown in lab?
M. Leprae (leprosy)
Rapid growers take how long to grow?
3-5 days
What is a common way for Mycobacterium tuberculosis to be transmitted?
respiratory route through aerosolized particles (Sneezing, coughing, breathing)
What are the 3 types of MTB infections?
- Primary
- Latent
- Reactivated
What are the two categories of those at high risk for developing TB?
1-Increased exposure to TB disease (Health care, prisons, drug users, immigrants)
2-Clinical conditions increasing risk of progression (AIDS, transplant,
Two step TB testing is done why?
To take advantage of the booster effect. First test may just “prime” immune system to respond the second second time if previous exposed
Blood test to check for TB measure what?
Interferon-Gamma release in samples exposed to antigen
What are 3 main clinical features of tuberculosis?
1-Cough with sputum
2-Shortness of breathe (dypsnea)
3-Fever/weight loss (action of IL-1 and TNF-a)
What are three common ways of collecting a specimen for diagnosis?
1-Respiratory sample (morning sputa, gastric aspirate)
2-Sterile tissue/body fluid (CSF, Bone, Pleural fluid)
3-Urine if Urinary tract disease signs
What are 4 methods to identify tuberculosis in the specimen?
1-AFB stain
2-PCR
3-Broth-based culture
4-Agar-based culture
What are the four Runyon groups of non tuberculosis mycobacteria (NTM)?
1-Photochromogens
2-Scotochromogens
3-Nonchromogenic
4-Rapid Growers
What characterizes a photochromogen?
- slow growth
- yellow-orange pigment in light
- M. Kansasii, M. Marinum (fish tank pathogen)
What characterizes a Scotochromogen?
- slow growth
- Yellow-orange pigment in light or dark
- M Scrofulacium (swamp water)
What characterizes a Nonchromogenic
- slow growth
- no pigment
- M. Avium-intracellulare
What characterizes a rapid grower?
- colony in 5 days
- no pigment
- M. Fortuitum, M. Chelonae-abscessus
Rapid growers are common of what type of infection?
Skin and soft tissue such as in cystic fibrosis or lung transplant
Lepromatous leprosy is ________ whereas tuberculoid leprosy is ______________
Widespread, well demarcated lesions
MTB and leprosy are spread _______ to _________ whereas NTM are contracted due to __________ exposure
Person, person, environmental
