Examination 4: Part II: Electric Boogaloo (Mycobacterium / Spirochetes)

Question 1

Do Mycobacteria spp. form spores?

Why is nutrient uptake more difficult for Mycobacteria?

What are mycolic acids?

Answer 1

No

because of the high lipid content of the cell walls

long fatty acids

Question 2

Staining characteristics for Mycobacteria

Answer 2

• Slender G+/v rods
• Acid fast

Question 3

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

Answer 3

Mycobacterium tuberculosis complex

Question 4

5 Runyon Groups are

Answer 4

• 1. Photochromogens
• 2. Scotochromogens
• 3. Nonphotochromogens
• 4. Rapid Growers
• 5. Non-cultivatable

Question 5

Photochromagens _____.

Scotochromogens _____.

Answer 5

require light to form pigment. Incubate in dark initially, then expose to light

produce pigment in dark or light conditions

Question 6

Nonphotochromagens are _____.

Answer 6

non-pigmented

Question 7

M. xenopi found in

M. xenopi infections include

Answer 7

hot water taps in hospitals

pulmonary and disseminated disease

Question 8

2 organisms in MAC

Answer 8

• M. avium
• M. cellulare

Question 9

Describe M. leprae

Answer 9

• Obligate intracellular bacteria
• Naturally found in armadillos and mice & causes leprosy

Question 10

What are the safety standards for Mycobacteria?

Answer 10

BSL 3

Question 11

Appropriate specimens for Mycobacteria

Answer 11

any tissue or organ (sputum, tissue/granuloma, urine, bone, CSF, blood, GI, stool)

Question 12

What is the purpose of digestion and decontamination followed by neutralization and concentration

Answer 12

• Kill normal flora bacteria that outgrow TB
• Release TB from cells and/or mucin

Question 13

Agents for digestion and decontamination include

Answer 13

• Trisodium phosphate (TSP)
• Zephiran
• 6% NaOH
• 5% Oxalic acid
• NALC NaOH method

Question 14

Specimen Processing steps (first three)

Answer 14

• Digestion
• Decontamination
• Neutralization

Question 15

Hot Staining method, aka

Cold staining method, aka

Answer 15

Ziehl Neelsen

Kinyon

Question 16

To report a slide as negative for Acid-Fast

Answer 16

must scan at least 300 oil immersion fields

Question 17

To report a slide as negative for Fluorochrome

Answer 17

must scan at least 30 400X fields

Question 18

What solid media are recommended? (2)

Answer 18

1 Agar based (Middlebrook 7H10 non-selective)

1 Egg-Potato based (Lowenstein-Jensis, Petragnani)

Question 19

What liquid media are available?

Answer 19

Middlebrook 7H9 broth

BACTEC 12B medium

Question 20

What does the secondary stage of syphilis consist of?

Answer 20

• Diffuse lesions
• 2-10 wks flu-like symptoms
• POSSIBLY continues into:
  
  • Latency period, wherein the disease becomes asymptomatic and subclinical

Question 21

What does Treponema pallidum subsp. pertenue
cause and how does it spread?

How is T pallidum identified

Answer 21

• Yaws in children
• Person-to-person via breaks in skin
• PCR, molecular techniques
• Serodiagnosis (Reagin)
• direct detection

Question 22

What are the morphological characteristics of spirochetes? How is Treponema pallidum usually treated?

Answer 22

Long, slender, coiled gram negative rods with flagella-like fibrils (providing motility) and an outer sheath. Penicillins.

Question 23

Describe the pathogenesis of Yaws.

Answer 23

• Skin lesions
• Disfigurement of nose/bones,
• Thickening, cracking of palms of hands, soles of the feet making walking painful

Question 24

What are the two causative agents of lyme disease?

What is the first stage of Lyme disease?

Answer 24

1. B. burgdorferi sensu stricto
2. Borrelia mayonii

• Specific: Erythema chronicum migrans (bulls eye lesion)
• Nonspecific: Headaches,fatigue, chills 3-30 days following exposure

Question 25

What are the second and third stages of Lyme disease?

Answer 25

* Joint and muscle pain, cardiac arrhythmias, carditis * Can occur weeks after after initial bite * Chronic arthritis, possibly neurologic involvement * 2-3 years after bite

Question 26

Two major spp. of Leptospira include...?

Answer 26

``` Leptospira interrogans (cause of human leptospirosis) Leptospira biflexa (environmental strains) ```

Question 27

Mycobacterium tuberculosis and kansasii are positive for

Answer 27

Niacin

Question 28

Specimen Processing steps (second three)

Answer 28

* Concentration * Set up Smears * Set up cultures

Question 29

What is the treatment for Borrellia

Answer 29

* 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.

Question 30

What species are part of the rickettsia spotted fever group?

Answer 30

* R. conorii (Israeli spotted fever) Europe, Middle east * R. rickettsii (Rocky mountain spotted fever) U.S.

Question 31

Treponema pallidum subsp endemicum causes _____ which is spread \_\_\_\_\_.

Answer 31

* Nonvenereal syphilis * mouth to mouth via utensils

Question 32

The primary stage of syphilis includes...

Answer 32

* Chancres, skin lesions at site of bacterial penetration (10-90d after the initial infections) * Bacteria proliferate and enter blood, lymphatics.

Question 33

Treatment for Yaws C trachomatis is responsible for _____ and \_\_\_\_\_.

Answer 33

One course of azithromycin PID, ectopic pregnancy

Question 34

Chlamydia characteristics

Answer 34

* 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.

Question 35

What spp are part of the Rickettsia typhus group?

Answer 35

* R. prowazekii (epidemic typhus) * R. typhi (murine ((endemic)) typhus( * fever * headache * rash * doxycycline is curative

Question 36

Which spp are obligate **intracellular** bacteria?

Answer 36

* Chlamydia * Anaplasma * Rickettsia * Ehrlichia

Question 37

**Erlichia signs/symptoms and treatment**

Answer 37

* Fever, headache, chills, vomiting, confusion, joint pain * 7-10 day course of doxycycline (tetracycline)

Question 38

How is Erlichia transmitted?

Answer 38

* 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

Question 39

Cell wall deficient bacterial spp.

Answer 39

* 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

Question 40

Aerobic actinomyces (3)

Answer 40

Nocardia, Streptomyces, Rhodococcus

Question 41

How is Borrellia identified?

Answer 41

* 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.

Question 42

Reticulate body, elementary body

Answer 42

Intracellular, extracellular (Chlamydia)