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1
Q

What are the transmission methods of spirochetes?

A

Sexual - syphilis
Vector - Lyme Disease
Environmental - Leptospirosis

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2
Q

Describe spirochete’s virulence factors?

A

Mainly to evade the immune system

They are not very antigenic so we are not able to make vaccines

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3
Q

Argylll Robertson Pupil

A

Pupil won’t constrict with light, but will constrict when attempting to focus on a nearby object

This is a sign of neurosyphilis

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4
Q

Jarisch-Herxheimer reaction

A

Flu-like symptoms 24 hours after treatment with antibiotics

This can be used to identify infection with spirochetes

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5
Q

Stages of Syphilis

A
  1. Chancre
  2. variable rash with flu-like symptoms
  3. Latency or dangerous cardiac or CNS involvement –> Gummas
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6
Q

Which type of bacteria can cross into the blood/brain barrier?

A

Spirochetes

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7
Q

Treatment for spirochetes?

A

Treatment is very simple as long as it is diagnosed early.

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8
Q

Which bacteria causes syphillis and which causes Lyme disease

A
  1. Treponema Pallidum

2. Borrelia Burgorferi

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9
Q

Which type of bacteria can easily cross into the bloodstream?

A

Spirochetes

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10
Q

How long does it take for a tick to transmit lyme disease?

A

24 hours

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11
Q

If Lyme disease is suspected in a prevalent area, what treatment should be taken?

A

doxycycline prophylaxis

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12
Q

Lyme Disease Phases

A
  1. Skin infection - Bull’s eye rash
  2. Immune or neurological issues
  3. Chronic - more severe neurological issues, fibromyalgia
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13
Q

Treatment for Lyme Disease

A

Doxycycline or amoxycillin for a month - no more

Jarisch-herxheimer reaction may occur, which will confirm diagnosis

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14
Q

What type of cell do spirochetes mostly infect?

A

endothelium

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15
Q

What two physical features define Vibrios?

A
  1. Curved

2. Gram (-) rods

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16
Q

Most vibrio pathogens are?

A
  • Ocean-dwelling

- several are halophiles - lives in high salt concentrations

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17
Q

What are the transmission methods of vibrios?

A
  1. Mostly fecal-oral –>gastroenteritis
  2. infect wounds contaminated by seawater or ocean debris
  3. H. Pylori causes peptic ulcers
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18
Q

Why are vibrios able to infect the GI tract, and cause peptic ulcers?

A

-Special virulence factors

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19
Q

What is an o1 genetic marker and where are they found?

A
  • marker of colonization by lysogenetic bacteriophage, which carries virulence markers
  • They are found on V. Cholera
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20
Q

Describe the transmission of v. Cholerae

A
  • transmitted to humans by the fecal-oral route
  • usually killed by stomach acid
  • if it survives it secretes mucinase to attach to and colonize the intestine
  • after colonizing it secretes an enterotoxin
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21
Q

What is choleragen?

A
  • an A-B subunit enterotoxin
  • interferes with signal transduction to cause massive watery diarrhea
  • This results in dehydration and electrolyte imbalance
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22
Q

How does H.pylori survive in the stomach?

A

-It produces urease which converts urea to ammonia
-ammonia neutralizes stomach acid, which irritates the stomach lining and allows bacteria to reproduce
-irritation and induction of apoptosis by pathogen causes ulcers which predispose to cancer
-

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23
Q

Urea breath test

A
  • used to diagnose H. Pylori

- patients who swallow radio-labeled urea and are infected with H. Pyloria - they will exhale radiolabeled CO2

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24
Q

Treatment of H.Pylori

A

10-14 course of three antibiotics (trio) with peptobismol and proton pump inhibitors

reinfection can occur

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25
Name four foodborne enterobacteria
1. Shigella 2. salmonella 3. E. Coli 4. yersinia
26
What are the two groups of enterobacteria opportunistic pathogens?
1. Klebsiella / enterobacter/ serratia | 2. Proteus/ providencia / morganella
27
List at least 3 defining characteristics of enterobacteria?
1. gram negative 2. nonsporulating 3. straight rods 4. facultative aerobes 5. catalase + 6. Oxidase - 7. Glucose fermenters
28
What is special about enterobacteria?
They are promiscuous to incorporating foreign DNA and acquiring virulence factors: This is a problem for risk of extreme antibiotic resistance for the entire group
29
Enterobacteria Antimicrobial sensitivity testing
1. Smear an agar plate with liquid culture of the patient isolate 2. place disks of various antibiotics on plate before overnight incubation 3. If successful plating-> lawns of bacteria are interrupted by zones of clearing 4. measure zones and compare to a table
30
Enterobacteria gut virulence factors
``` Gut virulence acquired factors: 1. Pili for adhesion 2. Type 3 secretion systems adhesion subversion of gut macrophage enterotoxin ```
31
Foodborne Enterobacteria pathogenesis
allow themselves to be sampled by M cells in peyers patches, where they alter local macrophages for bacterial survival and spread to the exterior surface of the gut (T3SS)
32
Which bacteria further use macrophages as trojan horses for passage into lymph nodes?
1. Local - Y. enterocolita - false appendicitis | 2. System wide - S . Typhi - Typhoid fever
33
Hemolytic Uremic Syndrome (HUS) is caused by which two bacteria?
- Shigella and EHEC
34
What causes HUS? What age group does it primarily affect?
- Release of shiga toxin into the bloodstream | - Pediatric patients
35
Reactive arthritis is caused by which five types of bacteria?
- Shigella - Salmonella - Yersinia - Campylobacter - Chlamydia
36
What is the transmission method of foodborne enterobacteria?
-Fecal oral
37
Who is especially susceptive to Reactive arthritis?
-Patients positive for HLA-B27
38
What are the symptoms of reactive arthritis?
- Conjunctivitis, urethritis, arthritis | - Can't see, can't pee, can't climb a tree
39
What type of pathogens are ICU bugs?
Opportunistic enterobacteria infections of noncomosial origin (from hospitals)
40
What are obligate anaerobes?
- They derive their ATP from fermentation pathways | - Most lack enzymes necessary to grow in the presence of oxygen -superoxide dismutase and oxidase
41
What is fermentation?
An energy-inefficient process that produces organic acids, alcohols, or even solvents as waste products
42
Anaerobic pathogens are either (2)
1. normal flora that escape their proper compartment --> form an abscess at new site 2. Soil organisms that enter the body either through wounds or through consumption of vacuum-packed food
43
Culturing of anaerobes -3 steps
1. Liquid media can be treated with reducing agents and tightly stoppered in a FULLY-filled container 2. agar plates must be incubated in anaerobic culture jar 3. Very sensitive anaerobes - glovebox
44
How to identify unknown anaerobes (3)
1. Gram stain 2. Biochemical tests 3. Gas chromatographic analysis of their fermentation products
45
Gram + anaerobes (2)
1. clostridia 2. actinomyces (All anaerobes except GNAB)
46
Anaerobes of normal flora (3)
1. GNAB 2. Actinomyces 3. C. Difficile
47
Anaerobes from the soil
The other clostridia (C. Tetani, C. botulinum, C. perfringens) These form spores which can enter through wounds or vacuum packed food
48
Anaerobic virulence
Exotoxin expression
49
Tetanus and botulism produce
neurotoxins
50
Anaerobic bacteria with tissue-degrading enzymes produce:
Gas gangrene and abscesses
51
Treatment of anaerobic infections
- concludes with antibiotics - abscess treatment - surgical care - draining and debriding - Toxigenic - antitoxin
52
GNAB
Gram Negative Anerobic bacilli | -Bacteroides and Prevotella , also includes Fusobacter
53
Why is TB such a successful pathogen?
It has been a major human disease for 5000 years and has consummately adapted to infect humans
54
Eradication of which type of bacteria seemed possible until AIDS?
M. Tuberculosis
55
Why is TB a public health nightmare?
MDR and XDR strains
56
Name 3 characteristics of mycobacteria
1. gram stain poorly 2. acid fast 3. very slow growing
57
Acid Fast staining procedure
1. carbolfuschin stain 2. Acid/alcohol decolorization 3. Methylene blue counterstain acid-fast +s hold carbolfuschin during decolorization --Mycobacterium - pink cords
58
Transmission of M. Tuberculosis
- Almost always to lung by inhalation - to lymph nodes, kidney, bones - CNS by hematogenous spread - GI by swallowing infected sputum
59
Immunocompetent response to TB
- Strong CMI - Can hold infection latent for decades - immunosenescence or suppression reactivates
60
Which bacteria is capable of hematogenous spread by intracellular infection of naive macrophages?
-TB
61
Describe the CMI response to TB
-CD8 cells kill infected macrophages and establish caseating granulomas in which the infection is contained
62
Why cytokine response is important to the granulomatous response to TB? and how is this proven?
- TNF alpha | - remicade - anti TNFalpha causes susceptibility to reactivation
63
What are the symptoms of classic TB?
Pulmonary: Cough, weight loss - consumption, fever, night sweats, hemoptysis - blood in sputum, chest pain
64
If you suspect someone has TB what should you do?
-check sputum and x-ray
65
What are some extrapulmonary manifestations of TB?
- scrofula- neck - GU tract - Meningitis or abscess -- CNS - Skeletal - long bone or vertebral - Miliary - GI - very rare for now
66
In a pediatric patient with TB what should you assume and do?
- must have been recently acquired - trace source! | - watch for miliary and meningitis
67
How do you determine exposure to TB? what else should you do?
- TST and or IGRA - 2 weeks | - perform antibiotic resistance testing as soon as cultures grow - another 3 weeks
68
Treatment of TB
- directly observed therapy with 4+ drugs featuring isoniazid - isolate patient for first two weeks
69
Vaccine for TB
- BCG - live attenuated M bovis - used abroad but not cost affective here - important because it can create weak-moderate false positive TST
70
What are the most helpful factors for reducing incidence of TB?
-Good diet and housing
71
Latent cases of which disease are NOT contagious?
TB
72
Atypical mycobacteria
-environmentally-acquired infections that cause neither TB or leprosy
73
Atypical mycobacteria infection in an: 1. immunocompetent adult 2. child 3. immunosuppressed
1. cutaneous 2. scrofula 3. systemic symptoms particularly from m kanasii or MAI/C
74
Which infections are especially difficult to treat once established?
Atypical mycobacteria - require multiple antibiotics
75
Is M. Leprae able to be cultured?
No! It is the slowest growing human pathogen and prefers 30-37 degrees
76
Describe the transmission of M. Leprae?
- extremely long incubation period - doesn't transmit easily - only 5-10% of humans susceptible
77
What are the two forms of Hansen's disease, what is the immune response to them, and what is their PPD status?
1. Tuberculoid - paucibacillary - -vigorous CMI - contains infection and damages nerves - -PPD+ 2. Lepromatous -multibacillary - -Weak MI - extensive cutaneous symptoms - -PPD-
78
What does lepromin PPD test ?
Immunocompetence NOT exposure
79
How would you treat an infection with M. Leprae?
Two years of dapsone + rifampin

Microbio Section 2 (1 decks)

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