Deck 44: Cell Walldeficient Bacteria: Mycoplasma and Ureaplasma

Question 1

Which of the following Mycoplasma species is associated with individuals who are positive for human immunodeficiency virus (HIV), is capable of invading human cells, and can modulate the immune system?

A) M. pneumoniae
B) M. genitalium
C) M. hominis
D) M. fermentans

Answer 1

D
The mycoplasmas associated with patients with HIV (M.fermentans, M.penetrans, M.pirum)are all capable of invading human cells and can modulate the immune system.Based on these findings, some investigators have proposed that these mycoplasmas might play a role in certain disease processes in these patients.

Question 2

Media that can be used for the isolation of Mycoplasma include:

A) Thayer-Martin agar with vitamin K.
B) 5% sheep blood and IsoVitaleX.
C) beef or soybean protein with serum and fresh yeast extract.
D) hemin and nicotinamide adenine dinucleotide (NAD) supplements.

Answer 2

C
In general, the medium for Mycoplasma isolation contains a beef or soybean protein with serum, fresh yeast extract, and other factors.Because these organisms grow more slowly than most other bacteria, the media must be selective to prevent the overgrowth of faster-growing organisms that may be present in a clinical sample.

Question 3

Caution should be taken when culturing blood in suspected cases of Mycoplasma infections since the organism is inhibited by which anticoagulant commonly found in commercial blood culture media?

A) Ethylenediaminetetraacetic acid (EDTA)
B) Sodium polyanethol sulfonate (SPS)
C) Heparin
D) Sodium citrate

Answer 3

B
Blood for culture of genital mycoplasmas should be collected without anticoagulants and immediately inoculated into an appropriate broth culture medium.SPS, the anticoagulant typically found in commercial blood culture media, inhibits Mycoplasmas.

Question 4

Which of the following agents lacks a cell wall and is the smallest known free-living form?

A) Chlamydia
B) Mycoplasma
C) Rickettsia
D) Coxiella

Question 5

Quality control is set up to test urea agar.M.genitalium and M.hominis are used; however, both organisms are negative for urease activity.Which one of the following statements explains these findings?

A) The urea agar is most likely expired.
B) The incubation time is most likely abbreviated.
C) A technical error has occurred.
D) These two organisms are poor choices for quality control of urea agar.

Question 6

The natural habitat of Mycoplasma spp., which causes infectious disease in humans, can best be described as the:

A) mucous membranes of humans.
B) aquatic environment.
C) natural environment.
D) genitourinary tract of animals.

Question 7

The laboratory method of choice to identify Mycoplasma and Ureaplasma infections is:

A) enzyme-linked immunosorbent assay (ELISA).
B) direct fluorescent antibody (DFA).
C) latex agglutination.
D) real-time polymerase chain reaction (PCR).

Question 8

Incorporation of urea into media is used to enhance the detection of which organism?

A) Ureaplasma urealyticum
B) Mycoplasma pneumonia
C) M. hominis
D) M. genitalium

Question 9

Which group of drugs is effective against Mycoplasma pneumoniae infections?

A) Beta-lactams
B) Sulfonamides
C) Cephalosporins
D) Fluoroquinolones

Question 10

The definitive identification of which of the following organisms is accomplished by hemadsorption techniques?

A) Chlamydia trachomatis
B) Mycoplasma hominis
C) Mycoplasma pneumoniae
D) Mycoplasma genitalium