Chlamydia, Rickettsia, Mycoplasma, and Similar Organisms

What is a reticulate body?

A more metabolically active body that EB reorganizes into; replicates by binary fission and releases new EBs after another reorganization occurs

What causes lymphogranuloma venereum?

Chlamydia Trachomatis

What are mycoplasmas?

Classified as Mollicutes; smallest free living organisms known; do not have cell wall and are pleomorphic; contain both RNA and DNA; replicate independently of a host; cannot synthesize cell wall components and therefore are resistant to all antibiotics that inhibit cell wall synthesis

What is a morulae?

Cluster of bacteria

Name the species of bacteria associated with the following infection: Q fever

Coxiella burnetti

What is the etiologic agent of ehrlichiosis?

E. chaffeensis--Human monocytic ehrlichiosis E. ewingii--Canine granulocytic ehrlichiosis

List the main types of infections attributed to Chlamydia trachomatis.

Endemic trachoma; nongonococcal urethritis, cervicitis, endometritis, proctitis, epididymitis, pelvic inflammatory disease, neonatal conjunctivitis, infant pneumonia; lymphogranuloma venererum

TRUE/FALSE: Ureaplasma parvum is known as "atypical pneumoniae" in cases of community-acquired pneumoniae.

False

What does the iodine stain show of C. trachomatis?

Glycogen inclusion (cytological method)

Mycoplasma pneumoniae is well-known for causing:

Lung infection; community-acquired pneumonia

Which organism can cause a cold-agglutinin?

Mycoplasma pneumoniae; nonspecific IgM-type antibodies found in ~50% of those infected; agglutinates type O red cells

Can Chlamydiae survive outside of the host cell?

No; they are obligate intracellular parasites

Name the species of bacteria associated with the following infection: Scrub typhus

Orientia tsutsugamushi

Most of the Mollicutes are resistant to which antibiotics?

Penicillin, β-lactams, sulfonamides, and rifampin

Who is likely to get an infection of psittacosis?

Psittacine birds (parrots and parakeets) Poultry and pet-shop workers and owners of avian pets

What is the causative agent of Brill-Zinser disease?

R. prowazekii

Which organism causes Rocky Mountain Spotted Fever?

R. rickettsi

Name the species of bacteria associated with the following infection: Rickettsialpox

Rickettsia akari

Name the species of bacteria associated with the following infection: Epidemic typhus

Rickettsia prowazekii Rickettsia typhi

Name the species of bacteria associated with the following infection: Rocky Mountain Spotted Fever

Rickettsia rickettsii

What does the DFA technique detect for Chlamydia testing?

The MOMP (major outer membrane protein) or LPS (lipopolysaccharide layer)

What is an elementary body?

The infectious particle that attaches to the host cell

Describe the infectious cycle of Rickettsia species.

Transmitted through the bite of an infected arthropod vector and attach to the host by cell surface receptors. Incubates for 3-14 days. Engulfed by endothelial cells of blood vessels and reaches cytoplasm of host cell. After phagocytosis, is multiples within the phagosome and released through cell lysis

Which of the following serotypes are associated with trachoma caused by C. trachomatis infections? a. A, B, Ba, C b. D through K c. L1, L2, L2a, L2b, L3 d. All of these are correct

a. A, B, Ba, C

Which of the following statements correctly describes the genus Chlamydia? a. Classified as viruses b. Do not contain both DNA and RNA c. Obligate intracellular bacteria d. Smallest free-living organisms known

a. Classified as viruses

At this time, the medically important cell wall-deficient bacteria include all of the following, except: a. Ureaplasma urealyticum b. Acholeplasma laidlawii c. Mycoplasma genitalium d. Mycoplasma pneumoniae

b. Acholeplasma laidlawii

Which statement is true regarding cell wall-deficient bacteria? a. Grow readily on routine culture media b. Highly fastidious c. Large in size d. Rapid grower

b. Highly fastidious

Mycoplasma pneumoniae: a. Responds well to penicillin therapy b. Is the etiologic agent of primary atypical pneumonia c. Is most often identified through culture and biochemical reactions d. All of these are correct

b. Is the etiologic agent of primary atypical pneumonia

In pathogenesis - the disease-causing mycoplasmas possess an ability to do all of the following, except: a. Invade human cells b. Remain extracellular c. Cause local cell injury d. Adhere

b. Remain extracellular

Each of the following statements correctly describes the mycoplasmas, EXCEPT: a. They contain both DNA and RNA b. They do not have a cell wall c. They cannot replicate on their own d. They are the smallest free-living organisms known

b. They do not have a cell wall

Regarding the classification of the cell wall-deficient bacteria - select the true statement: a. The genera is Mollicutes. b. The family is Mycoplasma. c. The family Mycoplasmataceae (this is the family that has been identified to colonize or infect humans), contains the genera Mycoplasma and Ureaplasma. d. The class is Ureaplasma.

c. The family Mycoplasmataceae (this is the family that has been identified to colonize or infect humans), contains the genera Mycoplasma and Ureaplasma.

The use of specific media formulations can yield the growth of a cell wall-deficient colony that appears as: a. Raised b. Circular c. Convex d. A fried egg

d. A fried egg These microorganisms cannot be detected using the standard Gram stain and routine culture procedures. The use of specific media formulations can yield growth of typical "fried egg-type" colonies. This appearance is quite different from the raised, circular, convex growth typically seen with many bacterial colonies having cell walls.

Each of the following conditions has been associated with C. trachomatis, EXCEPT: a. Lymphogranuloma venereum b. Nongonococcal urethritis c. Infant pneumonitis d. Atypical pneumonia

d. Atypical pneumonia

The agent in ornithosis is: a. Mycoplasma pneumoniae b. Chlamydophila pneumoniae c. Chlamydia trachomatis d. Chlamydophila psittaci

d. Chlamydophila psittaci

In the Mollicutes, transmission to humans occurs primarily through which of the following? Select the best answer: a. Transmission of respiratory secretions only. b. Direct sexual contact or respiratory secretions only. c. Direct sexual contact only. d. Direct sexual contact, transplanted tissue, in utero/childbirth, or via respiratory secretions.

d. Direct sexual contact, transplanted tissue, in utero/childbirth, or via respiratory secretions.

Cell wall-deficient bacteria are: a. Rapid growers b. Aerobes c. Bacteria that appear rod-like d. Microscopic single-celled organisms (prokaryotes) lacking a cell wall

d. Microscopic single-celled organisms (prokaryotes) lacking a cell wall