LABORATORY

Question 1

Specimens
• Throat swabs
• Nasopharyngeal swabs
• Throat washings
• Sputum
• Tracheal and transtracheal aspirate
• Bronchoscopy, BAL, and lung tissue specimens

Answer 1

Mycoplasma pneumoniae

Question 2

In the early stages of [?], diagnosis is made on clinical grounds. However, as the infection progresses several laboratory tests are available.

Answer 2

M. pneumoniae infection

Question 3

Gram staining in not useful in the detection of M. pneumoniae because of the absence of the [?]. It is of value only to eliminate other possible
pathogens.

Answer 3

cell wall

Question 4

is used as a fluorescent staining method used to detect mycoplasma.

Answer 4

Acridine Orange (AO) staining

Question 5

is a fluorochrome dye that binds nucleic acid. At a low pH under UV light, bacterial and fungal nucleic acid fluoresces orange whereas background mammalian nucleic acid fluoresces green

Answer 5

Acridine orange

Question 6

Mycoplasmas are very susceptible to adverse environmental conditions, so specimens should be placed into appropriate [?] as soon after collection as possible

Answer 6

transport or growth media

Question 7

are supplemented with Mycoplasma Supplement because Mycoplasma spp. are fastidious in their growth requirements

Answer 7

base media (PPLO agar and PPLO broth)

Question 8

Media for the isolation of M. pneumoniae are buffered at an initial pH of about

Answer 8

7.8

Question 9

, or both can be added to the base medium at the time of use to make it
selective against gram-positive and gram-negative bacteria that usually accompany mycoplasmas in
clinical materials

Answer 9

Thallium acetate or penicillin

Question 10

The base media may be supplemented with

Answer 10

glucose and phenol red indicator

Question 11

Inoculation and incubation of Mycoplasma pneumoniae

Inoculate the

Answer 11

complete medium (agar or broth)

Question 12

Inoculation and incubation of Mycoplasma pneumoniae

Incubate plates at 35 ± 2°C in a moist aerobic (or containing [?]) atmosphere

Answer 12

5% carbon dioxide

Question 13

Inoculation and incubation of Mycoplasma pneumoniae

Inspect the cultures daily for subtle changes because the organisms die rapidly once growth occurs and the substrates are utilized. If a potentially positive broth culture is detected visually, it is subcultured onto a [?] medium

Answer 13

solid agar

Question 14

Inoculation and incubation of Mycoplasma pneumoniae

It may take 2 -3 weeks to get a positive identification. Media for isolation of M. pneumoniae should be incubated for up to [?] before a final culture report is made

Answer 14

4 weeks

Question 15

M. pneumoniae colonies are round with a
dense center and a less dense periphery,
giving a [?] appearance on PPLO
(Mycoplasma) Agar. Vacuoles, large bodies characteristic of Mycoplasma spp., are seen in the periphery

Answer 15

“fried egg”

Question 16

In a medium containing glucose and phenol red, M. pneumoniae grows and produces acid, causing the color
of the medium to change from [?].

Answer 16

purple to yellow

Question 17

Culture of M. pneumoniae is a highly specialized test and is almost never done to diagnose mycoplasma infection. It is of little use to the clinician because recovery by culture and identification of the mycoplasmas take several weeks. Clinical diagnosis confirmed by

Answer 17

serology or PCR

Question 18

consists of examining serum samples for antibodies

Answer 18

Serodiagnosis

Question 19

autoantibodies agglutinating red blood cells at 4 oC; may be present in about 65% of patients after 1 to 2 weeks, with the maximum reached in the third or fourth week after onset. Titers greater
than 1:32 (i.e., titer of 1:54 or higher) are generally considered positive for M. pneumoniae; not specific because they are also seen in chronic lymphocytic leukemia (CLL), and infectious mononucleosis caused by Epstein-Barr virus.

Answer 19

Cold agglutinins

Question 20

There is a rise in specific antibodies to M. pneumoniae that is demonstrable by CF tests; acute and convalescent phase sera are necessary to demonstrate a fourfold rise in the CF antibodies. CF test for antibodies to M. pneumoniae is more specific.

Answer 20

Complement fixation (CF) test

Question 21

this test to detect IgM and IgG can be highly sensitive and specific and are considered more sensitive than CF tests

Answer 21

Enzyme-linked immunoassay (EIA)

Question 22

Several molecular methods, including PCR assay, have been developed since for the detection of M. pneumoniae in a variety of specimen type.

Answer 22

Molecular diagnosis

Question 23

Mucopurulent cervicitis

Answer 23

Endocervical swab, urine

Question 24

Acute urethral syndrome (women)

Answer 24

Urethral swab, urine

Question 25

Acute endometritis

Answer 25

Endometrial aspirate

Question 26

Acute salpingitis

Answer 26

Fallopian tube biopsy

Question 27

Nongonococcal urethritis (men)

Answer 27

Urethral swab, urine

Question 28

Inclusion conjunctivitis

Answer 28

Conjunctival scrapings/swab

Question 29

Trachoma

Answer 29

Conjunctival scrapings/swab

Question 30

Lymphogranuloma venereum

Answer 30

Lymph node aspirate, biopsy of ulcerated lesion, serum

Question 31

Pneumonitis (infants)

Answer 31

Serum, tracheobronchial aspirate, nasopharyngeal swab

Question 32

is the standard | method for demonstrating cytoplasmic inclusions.

Answer 32

Giemsa staining technique

Question 33

[?], which contains carbolfuchsin, is preferred because the inclusions are colored well, but the Giemsa stain is more generally available.

Answer 33

Gimenez stain

Question 34

are round and vacuolar, found in the cytoplasm | of epithelial cell, and often have a perinuclear location.

Answer 34

C. trachomatis inclusions

Question 35

Chlamydiae were named for the word [?], the ancient Greek term for the short cloak worn by Greek military men draped around their upper shoulders and secured with a brooch on the right shoulder.

Answer 35

chlamys

Question 36

The cytoplasmic inclusion of C. trachomatis was named [?] when they were discovered in the conjunctiva of the infected eye in an experiment conducted by German dermatologist and radiologist Ludwig Halberstädter and Austrian bacteriologist Stanislaus von Prowazek in 1907.

Answer 36

‘Halberstädter-Prowazek bodies’

Question 37

It is believed that the chlamydiae were named thus because the [?] formed by this agent inside host cells cluster around (are ‘draped’ around) the nucleus of the cell.

Answer 37

intracytoplasmic inclusions

Question 38

are commercially available for diagnosis.

Answer 38

Direct fluorescent antibody (DFA) and enzyme-linked immunoassay (EIA) kits

Question 39

uses monoclonal antibodies directed against a species-specific antigen on the chlamydial MOMP.

Answer 39

Direct fluorescent antibody (DFA)

Question 40

detects the presence of genus-specific LPS antigens extracted from EBs in the specimen. To be positive, the clinical specimen must contain a brightly fluorescing mass, in general morphology similar to Giemsa-stained inclusions, in the cytoplasm of epithelial cell, preferably adjacent to the nucleus.

Answer 40

enzyme-linked immunoassay (EIA)

Question 41

Specimens are added to cultures of susceptible cells, most often McCoy cells treated with cycloheximide to inhibit metabolism and enhance sensitivity. After incubation for 48-72 hours, the monolayers of infected cells are stained with iodine and examined for the presence of brown inclusions. Iodine stains glycogen in the inclusions. The presence of iodine-staining inclusions is specific for C. trachomatis since the inclusions of the other species of chlamydia do not contain glycogen.

Answer 41

Chlamydia trachomatis

Question 42

``` from infected humans are used to detect anti-Chlamydia antibodies by the complement fixation or microimmunofluorescence tests (an indirect fluorescent antibody technique). ```

Answer 42

Sera and tears

Question 43

for diagnosis are of limited value in adults, since the tests do not distinguish between current and past infections.

Answer 43

Serological tests

Question 44

Detection of [?] is indicative of a recent infection. Detection of IgM antibodies in neonatal infection is useful.

Answer 44

high titer IgM antibodies

Question 45

are the tests of choice for the diagnosis of C trachomatis infections because they have increased sensitivity compared to other test methods.

Answer 45

Nucleic acid amplification tests—NAATs

Question 46

The most commonly used molecular tests at present use

Answer 46

PCR, strand displacement, and transcription-mediated amplification (TMA)