AFB

What are the 4 general characteristics of acid fast bacteria?

strictly aerobes, slow growers, grow better w/ CO₂, high lipid content that resist decolorization w/ acid ethanol

What is M. tuberculosis transmitted?

by airborne droplets nuclei

What does m. tuberculosis cause to tissue?

caseation: tissue necrosis → soft crumbly cheese-like appearance

What are the 2 modes of transmission for m. leprae?

tuberculoid leprosy and lepromatus leprosy (most life threatening)C

Can M. leprae be cultured in vitro?

no

Where are NTM’s normally found? How are they transmitted?

in soil & water

opportunistic pathogen not normally transmitted human to human

What are the 3 most commonly isolated NTM?

avium, kansasii, ulcerans

Which NTM mimics symptoms of TB?

kansasii

What are the 4 photochromogenic species of NTM?

kansasii, marinum, simiae, szulgai

What are the 2 conventional staining methods? Which is heat/cold method? What is the primary stain & counterstain used?

Ziehl-Neelsen: heat, carbol fuchsin

Kinyoun method: cold, phenol added w/ carbol fuchsin

methelene blue counterstain

What is the primary stain, decolorizer, and counterstain for fluorochrome staining?

primary: auramine-rhodamine

decolorizer: weak form of HCl

counterstain: potassium permanganate

What is the advantage/disadvantage of fluorochrome staining?

most sensitive, but lots of insignificant bacteria

What is used as a decolorizer for modified acid-fast staining?

1% sulfuric acid instead of 3% HCl

What are the 3 solid medias used to incubate AFB?

LJ slant, Middlebrook 7H10,7H11, chocolate agar