Gram-weird Flashcards
What organisms do not gram stain well?
"These Microbes May Lack Real Color" Treponema Mycobacteria Mycoplasma Legionella Rickettsia Chlamydia
Why don’t treponema gram stain well?
Too small to be visualized
Why don’t mycobacteria gram stain well?
High lipid content in walls – take up carbolfuschin better (acid-fast)
Why don’t mycoplasma gram stain well?
No cell wall.
Why don’t Legionella gram stain well?
Primarily intracellular - silver stain instead
Why don’t Rickettsia gram stain well?
Primarily intracellular
Why don’t Chlamydia gram stain well?
Primarily intracellular, lacks classic peptidoglycan because of low muramic acid
On what kind of culture does Legionella grow?
Charcoal yeast extract with iron and cysteine.
How can legionella be detected?
Urine antigen
Where is legionella found? How is it transmitted?
Ubiquitous in water environments - air conditioning systems/cooling towers. Transmitted via aerosol. No person to person.
What allows legionella to be a facultative intracellular parasite?
- Dot/Icm type IV secretion system inhibits macrophage phagosome-lysosome fusion.
- Cu-Zn superoxide dismutase and catalase-peroxidase protects bacteria from oxidative burst
What are the clinical manfestations of legionella?
Legionnaires Dz: Severe pneumonia, associated with fever, GI and CNS sx.
Pontiac fever: Mild flu-like syndrome, usually self-limiting w/in 1 week.
How is legionella treated?
Macrolide or quinolone.
What is the reservoir of Chlamydia?
Humans.
How is Chlamydia transmitted?
Direct personal contact.