Examination 4: Part II: Electric Boogaloo (Mycobacterium / Spirochetes) Flashcards
Do Mycobacteria spp. form spores?
Why is nutrient uptake more difficult for Mycobacteria?
What are mycolic acids?
No
because of the high lipid content of the cell walls
long fatty acids
Staining characteristics for Mycobacteria
- Slender G+/v rods
- Acid fast
The following organisms are all a part of the _____.
- M. tuberculosis
- M. bovis and M. bovis BCG
- M. africanum
- M. caprae
- M. canettii
- M. microti
- M. pinnipedii
Mycobacterium tuberculosis complex
5 Runyon Groups are
- Photochromogens
- Scotochromogens
- Nonphotochromogens
- Rapid Growers
- Non-cultivatable
Photochromagens _____.
Scotochromogens _____.
require light to form pigment. Incubate in dark initially, then expose to light
produce pigment in dark or light conditions
Nonphotochromagens are _____.
non-pigmented
M. xenopi found in
M. xenopi infections include
hot water taps in hospitals
pulmonary and disseminated disease
2 organisms in MAC
- M. avium
- M. cellulare
Describe M. leprae
- Obligate intracellular bacteria
- Naturally found in armadillos and mice & causes leprosy
What are the safety standards for Mycobacteria?
BSL 3
Appropriate specimens for Mycobacteria
any tissue or organ (sputum, tissue/granuloma, urine, bone, CSF, blood, GI, stool)
What is the purpose of digestion and decontamination followed by neutralization and concentration
- Kill normal flora bacteria that outgrow TB
- Release TB from cells and/or mucin
Agents for digestion and decontamination include
- Trisodium phosphate (TSP)
- Zephiran
- 6% NaOH
- 5% Oxalic acid
- NALC NaOH method
Specimen Processing steps (first three)
- Digestion
- Decontamination
- Neutralization
Hot Staining method, aka
Cold staining method, aka
Ziehl Neelsen
Kinyon
To report a slide as negative for Acid-Fast
must scan at least 300 oil immersion fields
To report a slide as negative for Fluorochrome
must scan at least 30 400X fields
What solid media are recommended? (2)
1 Agar based (Middlebrook 7H10 non-selective)
1 Egg-Potato based (Lowenstein-Jensis, Petragnani)
What liquid media are available?
Middlebrook 7H9 broth
BACTEC 12B medium
What does the secondary stage of syphilis consist of?
- Diffuse lesions
- 2-10 wks flu-like symptoms
- POSSIBLY continues into:
- Latency period, wherein the disease becomes asymptomatic and subclinical
What does Treponema pallidum subsp. pertenue
cause and how does it spread?
How is T pallidum identified
- Yaws in children
- Person-to-person via breaks in skin
- PCR, molecular techniques
- Serodiagnosis (Reagin)
- direct detection
What are the morphological characteristics of spirochetes? How is Treponema pallidum usually treated?
Long, slender, coiled gram negative rods with flagella-like fibrils (providing motility) and an outer sheath. Penicillins.
Describe the pathogenesis of Yaws.
- Skin lesions
- Disfigurement of nose/bones,
- Thickening, cracking of palms of hands, soles of the feet making walking painful
What are the two causative agents of lyme disease?
What is the first stage of Lyme disease?
- B. burgdorferi sensu stricto
- Borrelia mayonii
- Specific: Erythema chronicum migrans (bulls eye lesion)
- Nonspecific: Headaches,fatigue, chills 3-30 days following exposure
What are the second and third stages of Lyme disease?
- Joint and muscle pain, cardiac arrhythmias, carditis
- Can occur weeks after after initial bite
- Chronic arthritis, possibly neurologic involvement
- 2-3 years after bite
Two major spp. of Leptospira include…?
Leptospira interrogans (cause of human leptospirosis) Leptospira biflexa (environmental strains)
Mycobacterium tuberculosis and kansasii are positive for
Niacin
Specimen Processing steps (second three)
- Concentration
- Set up Smears
- Set up cultures
What is the treatment for Borrellia
- Doxycycline in adults
- Doxycycline is contraindicated in children under 8-10 years of age, treatment is 14 day course of amoxicillin. No protocol for prophylaxis exists for children.
What species are part of the rickettsia spotted fever group?
- R. conorii (Israeli spotted fever) Europe, Middle east
- R. rickettsii (Rocky mountain spotted fever) U.S.
Treponema pallidum subsp endemicum causes _____ which is spread _____.
- Nonvenereal syphilis
- mouth to mouth via utensils
The primary stage of syphilis includes…
- Chancres, skin lesions at site of bacterial penetration (10-90d after the initial infections)
- Bacteria proliferate and enter blood, lymphatics.
Treatment for Yaws
C trachomatis is responsible for _____ and _____.
One course of azithromycin
PID, ectopic pregnancy
Chlamydia characteristics
- Obligate intracellular bacteria (previously considered a virus)
- Cannot be grown on cell-free media.
- Life cycle is similar to parasites
- Intracellular form termed a reticulate body
- Extracellular, inert form (elementary body) The EB cannot survive for long outside of a host cell.
What spp are part of the Rickettsia typhus group?
- R. prowazekii (epidemic typhus)
- R. typhi (murine ((endemic)) typhus(
- fever
- headache
- rash
- doxycycline is curative
Which spp are obligate intracellular bacteria?
- Chlamydia
- Anaplasma
- Rickettsia
- Ehrlichia
Erlichia signs/symptoms and treatment
- Fever, headache, chills, vomiting, confusion, joint pain
- 7-10 day course of doxycycline (tetracycline)
How is Erlichia transmitted?
- E. chaffeensis is transmitted by
- Lone Star Tick (Amblyomma americanum).
- Believed to be different than STARI
- Southern Tick Associated Rash Illness
- Tick needs to be attached to human skin for 24 hours to transmit the bacteria.
- Dogs, cats may serve as reservoirs
- Merck Manual
Cell wall deficient bacterial spp.
- Mycoplasma and Ureaplasma
- Smallest of known free-living bacteria (0.3 to 0.8 microns)
- Can be normal flora of the mouth, upper respiratory and genitourinary tract.
- Fastidious
Aerobic actinomyces (3)
Nocardia, Streptomyces, Rhodococcus
How is Borrellia identified?
- Serology is preferred method
- Cultivation is possible, numbers may be low
- Often can be seen in peripheral blood smears with the Wright’s stain before infection is clinically detected.
Reticulate body, elementary body
Intracellular, extracellular (Chlamydia)
