chlamydia

Question 1

Chlamydia species

Answer 1

Chlamydia trachomatis, Chlamydia psittaci, and Chlamydia pneumoniae.

Question 2

Chlamydia structure

Answer 2

Gram negative cocci or coccobacilli. Cell wall is atypical (peptidoglycan does not contain N-acetylmuramic acid). Small genome

Question 3

Chlamydia growth characteristics

Answer 3

obligate intracellular bacteria. Cant synthesize ATP or oxidize NADP (they depend on host cell for energy).

Question 4

chlamydia visualization

Answer 4

visualized by staining infected cells with Giemsa’s stain. Individual bacteria are not observed, but characteristic intracellular inclusions forming compact masses can be observed near the nucleus. Lugols iodine stains C. trachomatis inclusions brown b/c glycogen matrix

Question 5

Infectious form of Chlamydia

Answer 5

Elementary bodies are the infectious form- they have a condensed chromosome with electron-dense centers.

Question 6

Vegetative form of chlamydia

Answer 6

Reticulate bodies- multiply intracellularly

Question 7

Describe the life cycle of Chlamydia

Answer 7

Binary fission. Biphasic life cycle. Elementary bodies enter cell by endocytosis > Ebs are sequestered in inclusion > Differentiation into reticulate body > RBs develop in membrane bound vacuole via metabolic changes and reorganization of chromosome > RBs replicate for 24-72 hrs via binary fission > RBs reorganize and condense to form new EBs > host cell ruptures and frees EBs which infect other host cells

Question 8

Chlamydia antigens

Answer 8

LPS is common to all chlamydia. Specific outer membrane proteins (e.g., MOMP, 61 kD, 33 kD, 14 kD) are used to serotype the Chlamydia, and each serotype is associated with a particular disease

Question 9

chlamydia pathogenosis

Answer 9

Adhesins allow for attachment. Inhibit phagolysosome fusion. May cause latent infection

Question 10

Transmission of C. trachomatis

Answer 10

direct personal contact among humans (e.g. sexual transmission)

Question 11

Transmission of C. Psittaci

Answer 11

transmitted to humans by inhalation of bacteria in droplets or dust from birds and fowl

Question 12

Transmission of C. pneumoniae

Answer 12

transmitted by aerosols from person to person

Question 13

Chlamydia toxins

Answer 13

A heat-labile toxin is produced by infectious Chlamydia. The toxin is lethal to mice when injected intravenously. The specific role of the toxin in pathogenesis is unknown. Each serotype of Chlamydia produces a specific toxin

Question 14

Chlamydia latency

Answer 14

C. trachomatis may exist in a latent condition and be reactivated if an individual becomes immunosuppressed

Question 15

List the diseases caused by C. trachomatis and the serovariant

Answer 15

Serovariant A-C: trachoma, conjunctivitis. D-K: STDs, infant conjunctivitis, and pneumonia. L1-L3: lymphogranuloma venereum.

Question 16

List diseases caused by C. psittaci

Answer 16

Psittacosis (acquired from contact with birds)

Question 17

List diseases caused by C. pneumoniae

Answer 17

Pneumonia, upper respiratory disease

Question 18

Clinical manifestations of trachoma

Answer 18

Incubation period of 3-10 days. Conjunctivitis and follicular hypertrophy. Persistence of the infection produces corneal scarring and conjunctival deformity as a result of the severe inflammatory response. Scarring causes the eyelids to turn inward (trichiasis) thereby allowing the eyelashes to continually abrade the cornea.

Question 19

Hows is trachoma acquired

Answer 19

The infection generally is acquired in infancy from the mother or other close contact

Question 20

Trachoma treatment

Answer 20

surgery, antibiotics, facial cleanliness, environmental improvement

Question 21

Clinical manifestations of inclusion conjunctivitis

Answer 21

Mucopurulent conjunctivitis beginning 7-12 days after delivery. Infection may disseminate and cause pneumonia

Question 22

prevention/treatment of inclusion conjunctivitis

Answer 22

Antibiotics to infected pregnant women. Topical erythromycin or tetracycline, sometimes in combination with systemic antibiotics

Question 23

C. trachomatis urogenital tract infection (STD) clinical manifestations- uncomplicated

Answer 23

75% of women and 50% of men have no symptoms. In men, urethritis with dysuria and purulent discharge (PMNs but no bacteria seen on microscope). In women, mucopurulent urethritis, cervicitis and acute urethral syndrome

Question 24

C. trachomatis urogenital tract infection (STD) clinical manifestations of complications

Answer 24

Men: Epididymitis, proctitis, urethral stricture, disseminated infection, reactive arthritis. Women: Pelvic inflammatory disease, tubal infertility, ectopic pregnancy, bartholinitis, perihepatitis

Question 25

What proportion of women with PIC have c. trachomatis and what are the long term outcomes

Answer 25

50% of women with PID are infected with C. trachomatis. Can lead to scarring of fallopian tubes resulting in infertility, ectopic pregnancy, and chronic pelvic pain.

Question 26

which bacteria often co-occurs with c. trachomatis

Answer 26

N. gonorrhea

Question 27

c.trachomatis epidemioogy

Answer 27

Most frequently reported infectious disease in the United States

Question 28

Diagnosis of C. trachomatis

Answer 28

Nucleic acid amplification technology (NAAT) can be done with a urine sample or swab from the cervix or urethra. Tissue culture isolation is less sensitive and takes up to a week (NAAT only takes 4 hrs)

Question 29

Prevention/ treatment of c. trachomatis

Answer 29

Condomes/diaphragms. A single dose of azithromycin or 7 days of doxycycline (twice daily) are the most commonly used treatments. HIV-positive persons with chlamydia should receive the same treatment as those who are HIV negative

Question 30

Clinical manifestations of lymphogranuloma venereum

Answer 30

Begins as a small ulcer on the genitalia. The inguinal lymph nodes become swollen, and in 2 to 6 weeks they may suppurate and form draining sinuses. The initial lesion usually has disappeared by this stage. Lymphogranuloma venereum is one of the few chlamydial infections that can disseminate. The peritoneum may become involved, especially in women. Infection of the lower bowel in homosexual men causes a syndrome of ulcerative colitisBegins as a small ulcer on the genitalia. The inguinal lymph nodes become swollen, and in 2 to 6 weeks they may suppurate and form draining sinuses. The initial lesion usually has disappeared by this stage. Lymphogranuloma venereum is one of the few chlamydial infections that can disseminate. The peritoneum may become involved, especially in women. Infection of the lower bowel in homosexual men causes a syndrome of ulcerative colitis

Question 31

lymphogranuloma venereum epidemiology

Answer 31

It principally occurs in Africa and South America. The disease is rare in North America

Question 32

lymphogranuloma venereum treatment

Answer 32

Sulfonamides and tetracycline are very effective in early stages. Later stages require surgery

Question 33

How are the rates of chlamydia changing over time

Answer 33

They are increasing in men and women