finish of fastidious; Spirochetes
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- What is the only contagious acid fast bacilli?
- mycobacterium tuberculosis
- which mycobacterium of them all is most commonly isolated?
- m. tuberculosis
- what bacteria is the leading cause of worldwide death?
- Mycobacterium tuberculosis
- What happens in the course of the disease tuberculosis?
-
1. Macrophages/PMNs trying to rid AFB form tubercle.
2. Tubercle may liquify, form AFB-filled cavity in lungs.
3. Symptoms manifest as chronic cough and low fever. - What are the symptoms of tuberculosis?
-
-Chronic cough
-LOW-grade fever - What is Miliary tb?
-
Tb disseminated beyond lungs due to tubercles rupturing.
-Indicated by positive urine. - 2 types of TB skin tests:
-
-Mantoux
-Tine - What is the preferred TB skin test?
- Mantoux
- Why is Mantoux preferred to Tine for Tb skin test?
- Mantoux is a good deep injection; the Tine uses a disk w/ little needles- less sensitive of test.
- What is done if a TB skin test is +?
- Chest x-ray; to see if tubercle is visible. (lesion) If no lesion is visible it's possible that a vaccine caused the postiive skin test.
- What are the first line oral drugs for treatment of Tb?
-
-Isoniazid INH
-Rifampin RIF
-Pyrazinamide PZA
-Ethambutol EMB - What injectable drug treats Tb?
- Streptomycin
-
What AFB species is found in cows?
Disease it causes? -
Mycobacterium bovis
Disease similar to Tb, but rare in U.S. - What is BCG?
- an attenuated strain of M. bovis that is a vaccine for TB in endemic areas.
- What are the four Runyon groups?
-
-Photochromogens
-Scotochromogens
-Non-photochromogens
-Rapid growers - Distinguish. characteristic of Photochromogens
- Develop a yellow-orange pigment only when exposed to light, after growth.
- 2 species of Photochromogens:
-
Mycobacterium kansasii
M. marinum - What disease does M. kansasii cause, what group is it in?
- photochromogens; causes a chronic disease similar to Tuberculosis
-
What disease does m. marinum cause, what group is it in?
what specimen do you test for it? -
Skin disease from a water source; called swimming pool granuloma.
Skin specimen, incubated at 30 C - Distinguishing feature of Scotochromogens:
- produce a pigment in the DARK - before exposure to light
- 2 species of scotochromogens:
-
M. scrofulaceum
M. gordonae - What does M. scrofulaceum cause?
- scrofula of the neck - lymph node inflammation.
- what is M. gordonae known for?
- being a tap water contaminant; it can show up on a gram stain as a result, so we use distilled H2O.
- What is the distinguishing feature of non-photochromogens?
- they do not produce a pigment in either light nor dark
- what species of runyon group three is a very common isolate in AIDs patients?
- M. avium intracellulare complex
- What disease does M. avium intracel. complex cause?
- Pneumonia, or it disseminates to the skin, intestine, liver, and bone marrow.
- Where are M. ulcerans and M. haemophilum commonly found?
- on skin/in skin ulcerations of AIDS patients
- What is the disting. feature of Runyon group four?
- Rapid growers - they grow within 7 days.
- what is the most frequently isolated species of the rapid growers?
- M. fortuitum
- What does mycobacterium fortuitum cause?
- Soft tissue and bone infections after an injury
- Which of the rapid growers is a questionable pathogen
- M. smegmatis
- 5 methods for identifying Mycobacterium Species:
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1. Biochemical
2. HPLC (hipress. liq. chrom)
3. BActec/ESP/BacTAlert
4. Nucleic acid probe
5. PCR on specimen -
Fast method of Mycobacterium species id:
what is it? -
BacT Alert, Bactec, ESP
-detects the rate of growth of the bug - What bug causes leprosy?
- Mycobacterium leprae
- another name for M. leprae
- Hansen's bacillus
- 2 forms of leprosy:
-
-Lepramatous
-Tuberculoid -
Symptoms of Leprosy
-Lepramatous
-Tuberculoid -
Lep: bacilli are just under the skin surface and cause deformity.
Tub: bacilli infect nerve cells; skin turns to parchment w/ no sensation - How do you diagnose Leprosy?
-
Test for mycobacterium leprae;
-AFB smear
-Grow it - but only In Vivo; in an animal. no labs can grow it.
-By process of elimination - What bacteria is found in Armadillo footpads?
- M. leprae
- What disease is Mycobacterium paratuberculosis possibly associated with?
- Crohn's disease
- How is M. leprae transmitted?
- through EXTENDED, close and direct contact.
- What's a key biochemical trait of M. tuberculosis?
- It's always niacin positive, and the only Mycobact. (fortuitum is -/+)
- What is the distinguishing requirement for a bacteria to be spirochete?
- Bacillus with a minimum of 1 coil
- name of the antigen common to all spirochetes:
- Reiter protein - useful in identification
- What type of microscopic examination do you do for spirochetes?
- Darkfield; reflected light shows the organism as a light area on the slide.
- What fact re: spirochetes makes lab i.d. difficult?
- it can't be grown in lab
- what is the second most commonly isolated mycobacterium species?
- mycobacterium avium intracellulare complex (MAIC)
- what are the 3 genera of spirochetes?
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-Borrelia
-Leptospira
-Syphilis - What disease does Borrelia burgdorferi cause?
- LYMES disease
- Where was lyme's disease discovered?
- Old Lymes, Connecticuit
- How is lyme's disease transferred?
- by a vector - deer ticks; in places with high populations of white-tailed deer
- what are the three stages of symptoms of lyme disease?
-
Stage 1: Skin lesion called erythema chronicum migrans; flu-like symptoms.
Stage 2: Neurologic or cardiac abnormalities.
Stage 3: Arthritis - How is lyme disease diagnosed/detected?
-
-by detection of antibody
-culture (but its not practical)
-PCR (but there arent any specs to test) - Is there a treatment for lymes disease?
- YES -Doxycyline for 14-21 days;
-
What causes fusospirochetal disease?
Another name? -
Vincent's angina;
caused by Borrelia + fusobacterium, they are in a symbiotic relationship. -
What are the symptoms of Vincent's angina?
How do you confirm the diagnosis? -
Gingivits with a pharyngeal membrane.
Confirmed with a direct smear from membrane - you'll see the fused complex. - What are the three diseases caused by Borrelia?
-
-Lyme disease
-Vincent's angina
-Relapsing fever - What is relapsing fever caused by?
- 9 different Borrelia species
-
How is relapsing fever transmitted?
What kind of disease is it?
How is it detected? -
-ticks and lice;
-a Fevrile disease w/ a fever for 3-7 days, goes down, then goes back up.
-seen on a blood smear, so not detected in the microbiology lab, but haematology - What disease is caused by Leptospira, and what is it?
-
Leptospirosis; a zoonotic FEBRILE disease from rodent droppings.
(causes fever) - What is unique about the Leptospira genus compared to Borrelia and Treponoma?
- It can be cultured in lab
- What type of media is used for a Leptospira culture?
- -Fletcher's media.
- Incubation conditions for leptospira:
- Fletcher's media, 30'C, up to 6 weeks.
- What is the primary method of identifying Leptospira?
-
Serological tests for Antibody in the patient; not done in a typical lab, sent off to others.
NOT id'd with culture or stain. - what causes syphilis?
- Treponoma pallidum
- what is the most common species of Treponoma?
- Treponoma pallidum
- How is syphilis transmitted?
-
1. direct sexual contact
2. Congenitally; passes through the placenta during fetal development - What type of symptoms does an infant have when born with congenital syphilis?
-
2ndary symptoms - rash
Maybe Hutchinson's teeth - What do the 4 symptomatic phases of Syphilis consist of?
-
1. Hard chancre
2. rash
3. no symptoms
4. gummas - When are symptoms seen after initial Syphilis infection?
- on avg, 3 weeks; can be 10-90 days
- What happens during Primary Syphilis?
-
Hard chancre on genitalia, in mouth.
Disappears as bug goes into circulation.
A lesion smear is most reliable at this stage. - Problems with doing a lesion smear during primary syphilis:
-
-Other treponomas are normal flora; won't be abnormal to see on slide.
-Must use darkfield microscopy - not used to it, may have error. - Common I.D. method for Primary Syphilis:
- Immunoflourescent stain from a Chancre lesion smear
- What happens in 2ndary Syphilis - Symptoms, timecourse, then what?
-
-Rash appears mainly on trunk
-Represents hematogenous dissemination of the bug
-Appears 2-8 wks after chancre, resolves in 2-10 wks.
Serological identification is very reliable at this point. - When can/can't you do a Serological assay for antibody during Syphilis?
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NOT during primary - 25% of positive patients will test negative! Use FTA-ABS
YES during 2ndary - dissemination, bug is everywhere in blood. - What happens in latent syphilis?
-
-Rash rarely re-appears,
-No symptoms visible. - What happens in Tertiary Syphilis?
-
GUMMAS develop - tissue lesions (CNS, Cardiovasc).
Cause loss of musc. coordination, congenital heart failure, seizures, and you go insane. - How is Syphilis treated?
-
In Primary/Secondary phases, very susceptible to Penicillin, one large dose intramuscularly.
In 3ary, longer treatment necessary.
Gummas are irreversible. - Main way to diagnostically test for Syphilis?
-
(Treponema pallidum)
Serological test on serum/plasma - 2 broad categories of serol. testing:
-
-Non-treponemal tests - for reagin.
-Treponemal Ab tests - for Ab. -
2 types of Non-treponemal tests:
-what is this type of testing?
-Why is it done? What does it show? -
Screening. Shows every possible positive, and then some. Lots of false positives, but no false negatives.
1. VDRL (Venereal dis. research lab)
2. RPR (Rapid plasma reagin) - What is Reagin?
- Produced in response to tissue damage, which occurs in Syphilis - chancre
-
What are 2 Treponomal Ab tests?
What are they for, what do they tell? -
1. FTA-ABS (flouresc. treponemal antibody-absorbed)
2. Hemagglutination (MHATP)
Confirmatory tests, directly for treponema pallidum, no false positive. - Why do screening instead of just confirmatory testing for Syphilis?
- Screening is faster, easier to perform, and there are no false negatives.
-
What Treponema species causes YAWS?
What is YAWS? -
-Treponema pertenue
A skin disease in the tropics that causes hyperplasia - very very gross!! - Where are other Treponemes normal flora?
-
-Mouth
-Vagina
-Intestines - Which Treponeme is never normal flora?
- Treponema pallidum
- Pharyngeal membrane, gingivitis
-
Vincents Angina
Fusobacterium
Borrelia -
SYPHILIS:
(transmission reminder) -
not just an STD; babies get it too
Sex w/ the whole course
Congenital w/ secondary symptoms