Flashcards in Microbiology Test 1 Deck (31)
This mycobacteria does not grow in vitro
pigmented only after exposure to light (Runyoun Grp)
Group1 - Photochromogen
pigmented in dark and light (Runyoun Grp)
Group II - scotochromogen
non-pigmented (Runyoun Grp)
Group III - nonphotochromogen
Runyoun Group 4 characteristic
Etiological agent of TB
Many TV organisms are becoming Resistant to antibiotics mostly due to?
Lack of patience compliance. DIRECT OBSERVATION THERAPY(monitor patient ingestion using antibiotics) preferred
[M. fortuitum-chelonae Complex]These three clinically significant species have what key characteristic in common?
Etiologic agent of leprosy
(T/F) M.Tuberculosis is Niacin positive
True, M.Tuberculosis is Niacin positive
What antibiotics are prescribed to treat TB?
9 months with isoniazid & rifampin
once/day for 1st month then 2/per week
if R to isoniazid or rifampin then use
Organisms in the Mycobacterium Avium Complex include?
Primarily disease in poultry, swine
Found in natural waters, house dust
Large increase due to AIDS
pulmonary or disseminated
Both species very similar
M. avium- intracellulare
Common cause of non-TB mycobacterial pulmonary infection
isolated from water
human source unknown
using multidrug regimen to treat
Disease of fish
Cutaneous infections in humans
tender red or red-blue nodules
contact with poorly chlorinated & salt H2O
“swimming pool granuloma”
M. fortuitum-chelonae Complex (RAPID GROWERS) includes these organisms.
“Tap water bacillus”
water taps, soil
rare cause of disease
frequently isolated as transient resident
affects skin, mucus membranes and nerves
rare in US, western Europe
big problem elsewhere
transmission requires prolonged contact with infected person
Hansens Disease (leprosy)
What are the two forms of leprosy?
Tuberculoid and Lepromatous. Lepromatous being the much more malignant of the two.
Newer Mycobacteria Identification Methods
Radiometric culture system (BACTEC)
Nucleic acid probes (rRNA)
Tuberculin skin test at least
(T/F) not all disinfectants are tuberculocidal
sodium hypochlorite (bleach)
is used. Also disposable equipment.
(T/F) You can refrigerate specimens for up to 24 hours
True. You can refrigerate specimens for up to 24 hours
[Specimens] How many positive smears is diagnostic for Mycobacteria?
2 or more smears out of 3 is diagnostic
none or 1 smear positive then
need more specimens
What is the preferred urine sample for Mycobacteria?
first AM midstream preferred (can refrigerate)
Why are mycobacteria so hard to stain?
** high lipid content in cell wall protective
A nonpigmented mycobacteria is isolated that reduces nitrate to nitrite and is niacin-positive. What should you suspect?
This detects a cell-mediated immune response to mycobacterial antigens
Skin test for TB
Group 1 Photochromogen species include
M. Kansasii, M. Marinum, and M simiae