Atypical Bacteria

Question 1

What are the three species of the genus Chlamydia?

Answer 1

C. psittaci, C. pneumoniae, C. trachomatis

These species are significant in the context of atypical bacterial infections.

Question 2

What type of parasites are Chlamydia species?

Answer 2

Obligate intracellular parasites

They lack independent energy-producing metabolic pathways.

Question 3

What is the first step in the reproductive cycle of Chlamydia?

Answer 3

Uptake into host cell by energy requiring phagocytosis

Involves small elementary bodies (EB).

Question 4

What is the most common sexually transmitted bacterial pathogen in the US?

Answer 4

C. trachomatis

Responsible for 4-10 million new cases per year.

Question 5

What are common infections caused by C. trachomatis in males?

Answer 5

Non-gonococcal urethritis, epididymitis, prostatitis

These conditions are part of the spectrum of STDs.

Question 6

What are common infections caused by C. trachomatis in females?

Answer 6

Urethritis, follicular cervicitis, endometritis, proctitis, salpingitis, PID

These infections can lead to serious reproductive health issues.

Question 7

How can newborns become infected with Chlamydia?

Answer 7

By passage through an infected birth canal

Can lead to conjunctivitis, nasopharyngeal infections, and pneumonia.

Question 8

What is the most commonly used method for direct microscopic examination of Chlamydia?

Answer 8

Direct fluorescent antibody testing

Used for detection in endocervical scrapings.

Question 9

What cell lines are used for culturing Chlamydia?

Answer 9

McCoy, HeLa 229, BHK-21, Buffalo Green Monkey kidney cells

These cultures help in laboratory diagnosis.

Question 10

What is the technique most commonly used for rapid detection of C. trachomatis antigen?

Answer 10

Enzyme Immunoassay

Positive results should be verified due to potential false positives.

Question 11

What is a common clinical manifestation of C. pneumoniae infection?

Answer 11

Pneumonia, pharyngitis, and acute respiratory disease

Associated with a biphasic clinical course.

Question 12

What is psittacosis and what causes it?

Answer 12

A pneumonia-type respiratory infection caused by C. psittaci

Typically associated with exposure to psittacine birds.

Question 13

How is psittacosis diagnosed?

Answer 13

Based on history of exposure to psittacine birds and a fourfold rise in antibody to chlamydial group LPS antigen

Diagnosis often requires serological testing.

Question 14

What type of bacteria are Rickettsia spp.?

Answer 14

Obligate intracellular bacteria

Question 15

What are the primary vectors for Rickettsia spp. infections?

Answer 15

• Ticks
• Mites
• Fleas
• Lice
• Chiggers

Question 16

What is the generation time for Rickettsia spp. inside eukaryotic cells?

Answer 16

8-10 hours

Question 17

Can Rickettsia spp. be grown on artificial laboratory media?

Answer 17

No

Question 18

What is the most important and common rickettsiosis in the US?

Answer 18

Rocky Mountain Spotted Fever

Question 19

Which organism causes Rocky Mountain Spotted Fever?

Answer 19

Rickettsia rickettsii

Question 20

How are R. rickettsii transmitted to humans?

Answer 20

Via a tick bite

Question 21

What conditions are associated with epidemic typhus?

Answer 21

• Low socioeconomic conditions
• Poverty
• Crowding
• Unsanitary conditions

Question 22

What causes murine typhus (endemic typhus)?

Answer 22

Rickettsia typhi

Question 23

What are the transmission methods for Q fever?

Answer 23

Via aerosols

Question 24

What antibiotics are used to treat rickettsial infections?

Answer 24

• Doxycycline
• Tetracycline
• Chloramphenicol
• Fluoroquinolones

Question 25

What are the general characteristics of Mycoplasma?

Answer 25

Pleomorphic, no cell wall, slow growing, highly fastidious, facultative anaerobes ## Footnote M. pneumoniae and M. hominis are strictly aerobic exceptions

Question 26

What respiratory disease is caused by Mycoplasma pneumoniae?

Answer 26

Primary atypical pneumonia (walking pneumonia) ## Footnote Causes 20% of pneumonia cases in school-age children and young adults

Question 27

What diseases can Mycoplasma hominis cause?

Answer 27

Infections of the upper genitourinary tract, including salpingitis, pyelonephritis, PID, and postpartum fevers ## Footnote Can also be part of normal flora in some individuals

Question 28

What is the primary laboratory diagnosis method for Mycoplasma pneumoniae?

Answer 28

Serology ## Footnote A fourfold rise in acute and convalescent serum is used as diagnostic criteria

Question 29

What is the common morphology of Mycoplasma colonies?

Answer 29

Fried egg appearance ## Footnote Typical for M. hominis colonies

Question 30

True or False: Mycoplasma pneumoniae is part of the normal flora.

Answer 30

False ## Footnote M. pneumoniae is not part of the normal flora

Question 31

What specimens can be collected for Mycoplasma diagnosis?

Answer 31

Body fluids such as blood, synovial fluid, CSF, wound aspirates, and respiratory secretions ## Footnote Tissue samples may also be submitted

Question 32

Fill in the blank: Mycoplasma hominis and Ureaplasma urealyticum can be transmitted to the fetus at delivery causing _______.

Answer 32

Meningitis and disseminated disease

Question 33

What is a common laboratory challenge in diagnosing Mycoplasma?

Answer 33

Culture is rarely attempted due to technical difficulties ## Footnote Mycoplasmas are hard to grow in laboratory settings

Question 34

What is the significance of U9B medium in Ureaplasma identification?

Answer 34

Used to test urease activity directly on solid medium ## Footnote Urease positive colonies appear dark golden brown

Question 35

What type of microscopy is required to view Ureaplasma colonies?

Answer 35

Stereoscopic microscope ## Footnote Ureaplasma colonies are extremely small

Question 36

What techniques are now available for the detection of serum antibodies for M. pneumoniae?

Answer 36

Enzyme immunoassay and microimmunofluorescence ## Footnote These techniques can detect both IgM and IgG antibodies.