Antimycotic agents Flashcards
What is the different protein that makes up part of the cell wall in mycobacteria?
Mycolic acid
What is the classic culture result for mycobacterium?
Acid-fast
What does mycobacterium avium complex cause?
Pulmonary and disseminated infections
What does mycobacterium lepra cause?
leprosy
What is mycolic acid?
Lipid in the cell wall of TB
What is the gram stain of mycobacterium? Why?
gram stain poorly or not at all due to mycolic acid structure
Where does TB like to replicate?
macrophages
How fast does TB grow?
Slowly
What is the morphology of TB?
Rod
What infection is closely correlated with TB infection?
HIV
How is TB transmitted?
Respiratory droplets
True or false: most patient infected with TB show some type of symptoms
false-90% are asymptomatic
What are the classic symptoms for TB infection?
Night sweats
Weight loss
Hemoptysis
Fever/chills
In latent TB infection, what are the ssx? CXR results? Sputum smears/cultures? Are they infectious?
Nothing will show positive, except for blood tests (IFN-gamma release)
They are not infectious
What are the diagnostic criteria for active TB?
Positive blood tests
CXR abnormal
sputum
What is the IFN-gamma test for TB?
Expose WBCs of a pt to TB antigen, and see if they produce IFN-gamma. If they do, then positive for infection
What are the obstacles of treating TB?
Slow growing
Toxicity of TB drugs
Resistance
Why are patient not compliant with TB drugs?
Really toxic
Why do you always treat TB with 3-4 different drugs?
Resistance
What is the MOA of rifamycin? Is it bactericidal or bacteriostatic? Why is this drug particularly useful for treating TB?
Inhibits RNA synthesis by targeting bacterial RNA polymerase
Bactericidal
Goes into macrophages
What is the MOA of streptomycin?
Inhibits protein synthesis by targeting the 30s subunit
What is the MOA of isoniazid? Is this bactericidal or bacteriostatic? Why is this drug particularly useful for treating TB?
Inhibit mycolic acid synthesis by forming covalent bond with two proteins
Bactericidal
Can go into macrophages
What is the MOA of Ethambutol?
Inhibit arabinosyl which inhibits cell wall synthesis
What is the MOA of pyrazinamide? This is a synthetic analog to what compound?
Inhibits cell membrane synthesis (somehow?)
Synthetic analog to nicotinamide
What are the bacteria that are a part of the mycobacterium avium complex?
M. Avium
M. intracellulare
What are the ssx of MAC infection? In whom does each type of infection occur?
Pulmonary disease in immunocompetent individuals and disseminated disease in AIDS pts
How are the MAC bacteria acquired?
ingestion of contaminated food and water
What is the preferred regimen for active TB infection? (4 drugs, how long?)
Daily INH, Rifampin, pyrazinamide, and ethionamide x8 weeks