Deck 43: Cell Walldeficient Bacteria: Mycoplasma and Ureaplasma

Question 1

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 1

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 2

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.

Answer 2

D
Both M.genitalium and M.hominis are negative for urease activity;therefore they are poor choices to test the validity of the agar.Either one of these organisms,along with U.urealyticum,should have been used;they are both negative and positive for urease activity,respectively.

Question 3

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.

Answer 3

A
Mycoplasmas are part of the microbial flora of humans and are found mainly in the oropharynx,upper respiratory tract,and genitourinary tract.Besides those that are considered primarily as commensals,considerable evidence indicates the pathogenicity of some mycoplasmas;for others,a role in a particular disease is less clearly delineated.

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

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

A)U.urealyticum
B)M.pneumoniae
C)M.hominis
D)M.genitalium

Question 6

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.

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

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

Question 9

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)Mycoplasma fermentans

Question 10

Which group of drugs is effective against M.pneumoniae infections?

A)b-Lactams
B)Sulfonamides
C)Cephalosporins
D)Fluoroquinolones