Miscellaneous Organisms

Question 1

What are the general characteristics of spirochetes and the genera involved with human infections?

Answer 1

Spiral microbes that can be from 5-20 um in length. They have a flexible cell wall and are motile. They can use several energy sources including carbs., AAs, long chain FA or alcohols. They are gram neg, and are in two families.

Leptospira - Leptospiraceae
Borrelia, and Treponema - Spirochaetaceae

Question 2

What are the species of Treponema that attack humans and their mode of transmission?

Answer 2

Treponema pallidum subsp. pallidum - syphillus (direct sex contact)

T. pallidum subsp. pertenue - yaws (direct contact)

T. carateum - pinta (person to person contact)

T. pallidum subsp. endimicum - endemic syphilis (betel) transmitted by direct contact

Question 3

Differentiate the different phases of syphilis, discuss the non-treponemal and treponemal tests that will appear positive in each phase:

Answer 3

Primary: 10 to 90 days primary lesion/chancre (low sens for both)

Secondary: 2 to 12 weeks after primary lesion (high sens for both)

Tertiary: no longer contagious unless recurrence to secondary phase (high sens in treponemal tests)

Nontreponemal tests

VDRL - venereal disease research lab
Flocculation - cardiolipin antigen
RPR - agglutination bound cardiolipin with a carbon particle

Question 4

What are the characteristics and diseases caused by Leptospira and Borrelia?

Answer 4

Leptospira - Tightly coiled spirochete with a hook on the end, aerobes, cannot grow on artificial media, non specific influence symptoms, Leptospirosis from dog or rat urine

Borrelia - B. recurrentis - relapsing fever, acute infection with febrile episodes that can last weeks
B. burgdorferi - lyme disease

Question 5

What are the vectors involved with the transmission of Leptospira and Borrelia?

Answer 5

Leptospira - Dog or rodent urine

Borrelia recurrentis - treatment tetracyclines
(endemic relapsing fever - louse born)
(epidemic relapsing fever - tick born)

Borrelia burgdorfei - Ixodes tick - early doxycycline or amoxicillin - Late = ceftriaxone

Question 6

Discuss the symptoms and progression of Lyme disease:

Answer 6

1 - Fever, headache, flu like symptoms, ECM (erythema chromium migrans rash)
2 - Disseminated secondary skin lesions, migratory joint and bone pain, neurologic and cardiac pathology
3 - joint, cardiac and neurological systems involved

Question 7

What are the general characteristics of the Chlamydia microbe?

Answer 7

Known as an obligate intracellular parasite, belongs to bacteria, host cells (columnar or transitional epithelial cells)

Question 8

List the two genera found in the Chlamydiaceae family that attack humans, the mode of transmission, the body site usually involved and the treatment:

Answer 8

Chlamydia
C. trachomatis - sexually transmitted, trachoma, lymphogranuloma venereum, sulfa drug sensitive, cell culture is gold standard

Chlamydophila
C. pisttaci - from birds, acute respiratory disease, usually sulfa resistant another antibiotic necessary

C. pneumoniae - human transmission C acute resp. pathogen, otitis media, effusion, pneumoniae, usually sulfa drug resistant

Question 9

Explain the life cycle of the Chlamydia:

Answer 9

0 hours - Elementary body (infectious stage)
8 hrs - organize into reticulate bodies
24 hrs - reorganize into elementary bodies
30 hrs - multiplication stops
35-40 hrs - host cell dies, releasing EBs

Question 10

What are the general characteristics of Mycoplasmas?

Answer 10

No cell wall, fastidious, facultative, and need media with cholesterol and FA for growth

Question 11

Identify the diseases caused, the treatment and ID transmission of Mycoplasma and Ureaplasma:

Answer 11

M. hominis - urogenital infect. sex trans. Vancomycin

Ureaplasma urealyticum - urogenital infect. sex trans. Erythromycin

M. pneumoniae - atypical pneumonia, droplet transmission, Erythromycin

Question 12

What are the general characteristics of Rickettsiae?

Answer 12

Gram neg rods, short, will not grow in cell-free media, arthropod hosts

Question 13

List the genera of the family Rickettsiaceae and Anaplasmataceae:

Answer 13

Rickettsiaceae

• Rickettsia
• Orienta

Anaplasmataceae

• Ehrlichia
• Anaplasma
• Cowdria
• Wolbachia
• Neorickettsia

Question 14

What are the diseases caused by the spotted fever group of rickettsia?

Answer 14

Rocky mountain spotted fever - R. rickettsii
Boutonneuse fever (Mediterranean spotted fever) - R. conorii
Rickettsial pos - R. akari

Question 15

What are the diseases caused by the typhus group of rickettsia?

Answer 15

Epidemic typhus - Arthropod vector - R. prowagekii )Brill - zinsser disease)

Endemic (murine) typhus - Louse vector - R. typhi

Rocky Mountain Spotted Fever - R. rickettsia

Question 16

What is the cause of scrub typhus, trench fever and Q fever?

Answer 16

Scrub typhus - Orient tsutsugamushi

Trench fever - Bartonella quintana

Q fever - Coxiella burnetii

Question 17

Discuss Ehrlichia sp. in regards to: the characteristics of the microbe, the mode of transmission, symptoms, and clinical identification:

Answer 17

Characteristics - Obligate intracellular parasite

Transmission - arthropod borne, gram neg coccobacilli multiply in the phagosomes of host WBCs

Symptom - fever, leukopenic, anemic, and thrombocytopenia

Clinical ID: inclusion in WBC, causes morulae