Mycobacteria Flashcards
Vertical transmission
transmission of organism from mother to fetus
TORCH
Toxoplasma gondii
Cytomegalovirus
Human papillomavirus HPV
Mycobacteria general info
Slender, non motile, non spore forming, obligate aerobes
resist gram staining because of lipids in their cell wall that prevent penetration of crystal violet and safranin
referred to as acid fast bacilli (AFB)
Mycobacteria staining
Ziehl neelsen
Kinyoun
Fluorochrome
Ziehl neelson stain
requires heating during staining
Kinyoun stain
does not require heating
Fluorochrome stain
with auramine/rhodamine staining as the primary stain
2% NaOH
used for decontamination
NALC
mucolytic agentthat liquefies mucus in respiratory specimens, releasing the mycobacteria
LJ media
agar based and contains egg components for growth and malachite green to inhibit growth of normal flora
Middlebrook agar
contains 2% glycerol to support better growth of some species
Photochromogens
produce non pigmented colonies when grown in the dark and pigmented colonies after exposure to light
Scotochromogens
produce deep yellow to orange pigmented colonies when grown in either light or dark
Nonchromogens
non pigmented in both light and dark
Mycobacterium tuberculosis test
skin test
TB skin test
injected intradermally and examined 24 hours later for redness and swelling
(+) indicates previous exposure but not necessarily active
M. TB first line drugs
Isoniazid
Rifampin
Ethambutol
Pyrazinamide
Isoniazid drug
inhibits synthesis of mycolic acid
Rifampin drug
inhibits RNA synthesis by inhibiting RNA polymerase
Ethambutol drug
inhibits cell wall synthesis
Pyrazinamide drug
inhibits multiple targets such as energy production and translation of mRNA
Multidrug (R) M. TB
simultaneous (R) to both isoniazid and rifampin
extremely drug (R) M. TB
(R) to isoniazid and rifampin, plus (R) to any fluoroquinolone, and at least one of the 3 second line drugs (capreomycin, kanamycin, amikacin)
Mycobacterium bovis
causes TB in warm blooded animals
human disease is zoonosis
Mycobacterium kansasii info
isolated from tap water
no person to person spread
rarely disseminates
Mycobacterium marinum info
fresh and saltwater
typical infections involve skin
usually presents as single nodular lesion confined to one extremity
fish tank or swimming pool granuloma
Mycobacterium gordonae info
freshwater (tap water)
rarely pathogenic - isolated as contaminant in labs
can lead to pseudo outbreaks
Mycobacterium marinum
fish tank or swimming pool granuloma
Mycobacterium scrofulaceum info
environmental water source
causes scrofula in children
Mycobacterium xenopi info
hot water systems
causes primary pulmonary disease
nosocomial and pseudo infection from water storage tanks in hospitals
Mycobacterium avium complex info
important pathogens of poultry and swine
most common environmental causing disease in humans
isolated in up to 20% cystic fibrosis patients
M avium antimicrobial therapy
Clarithromycin
Rifampin
Ethambutol
Rifabutin
Clarithromycin drug
protein synthesis inhibitor
Rifabutin drug
inhibits RNA synthesis
Mycobacterium haemophilum info
multiple painful subcutaneous nodules commonly involving extremities
eyebrow and tattoo procedures
ferric ammonium citrate or hemin is growth requirement
Mycobacterium ulcerans info
stagnant water
causes painless lump under skin - shallow non healing ulcer
M ulcerans - Africa
Buruli ulcer
M ulcerans - Australia
Bairnsdale ulcer
Mycobacterium fortuitum info
post traumatic wound infections, osteomyelitis, joint infections and infections of the eye
Mycobacterium chelonae info
disseminated cutaneous disease
outbreaks occurred after acupuncture therapy
Mycobacterium abscessus info
pulmonary infections (cystic fibrosis patients) chronic otitis media (associated with ear tube placement)
Mycobacterium leprae info
humans reservoir with shedding from nose (armadillo)
causes leprosy (Hansens disease)
cannot be cultured using agar or liquid based culture media
M. tuberculosis ID
optimal growth 37C
niacin (+)
nitrate (+)
growth on T2H (+)
M. bovis ID
optimal growth 37C
M. kansasii ID
optimal growth 37C photochromogen nitrate (+) semiquantx catalase >45 68C catalase (+) growth on T2H (+)
M. marinum ID
optimal growth 30C
photochromogen
growth on T2H (+)
M. gordonae ID
optimal growth 37C scotochromogen semiquant catalase >45 68C catalase (+) growth on T2H (+)
M. scrofulaceum ID
optimal growth 37C scotochromogen semiquant catalase >45 68C catalase (+) growth on T2H (+)
M. xenopi ID
optimal growth 42C
scotochromogen
68C catalase (+)
growth on T2H (+)
M. avium ID
optimal growth 37C
growth on T2H (+)
M. haemophilum ID
optimal growth 30C
growth on T2H (+)
M. ulcerans ID
optimal growth 30C
68C catalase (+)
growth on T2H (+)
M. fortuitum ID
optimal growth 30C growth rate <=7 days nitrate (+) semiquant catalase >45 68C catalase (+) growth on T2H (+) growth on MAC (+) iron uptake (+)
M. abscessus ID
optimal growth 30C growth rate <=7 days semiquant catalase >45 68C catalase (+) growth on T2H (+) growth on MAC (+)
M. chelonae ID
optimal growth 30C growth rate <=7 days niacin (+/-) semiquant catalase >45 68C catalase (+) growth on T2H (+)
