Gram- Cocci

Question 1

what are two reasons that a beta lactam antibiotic such as cephalosporin does not work to clear up a chlamydia infection?

Answer 1

1. chlamydia are intracellular pathogens and beta lactams don’t penetrate host cells very well 2. chlamydia does not have peptidoglycan (cephalosporins disrupt the synthesis of the peptidoglycan layer forming the bacterial cell wall)

Question 2

Which of the following statements about Neisseria is FALSE?

A. they have LOS instead of LPS in their outer membrane

B. they are obligate aerobes but prefer a CO2 enriched environment

C. N. gonorrehoeae has the same general characteristics as N. meiningitidis

D. N. gonorrehoeae’s virulence factors include IgA1 protease, opa protein, pili for adhesion to host, endotoxin, and an antiphagocytic capsule

E. N. gonorrehoeae utilizes programmed antigen variation and opacity proteins to evade the immune system

Answer 2

D.

Neisseria gonorrhoeae is unencapsulated.

Question 3

Which of the following is incorrectly matched?

A. Chlamydia trachomatis: STI infections

B. Chlamydia psittaci: eye infections

C. Chlamydia pneumoniae: pneumonia

D. Chlamydia trachomatis: produces glycogen

E. Chlamydia pneumoniae: atherosclerosis

Answer 3

B.

• Chlamydia psittaci*, otherwise known as ornithosis/parrot fever, is transmitted via psittacine birds and causes an influenza-like disease.
• Chlaymydia trachomatis* also causes eye infections and should be treated with a non-penicillin antibiotic, such as azithromycin or doxycycline.

Question 4

chlamydial cells that are not infectious but are metabolically active inside a host cell and grow to form an inclusion

Answer 4

reticulate bodies

Question 5

this mucopurulent chlamydia infection is the leading cause of blindess in under-developed countries and is associated with poverty

Answer 5

ocular trachoma (serotypes A-C)

Question 6

“nongonococcal urethritis” that may lead to PID and sterility in females if left untreated, and is a frequent cause of postgonococcal urethritis

Answer 6

gential trachoma

Question 7

chlamydia infection that is transmitted from mothers to babies through the birth canal and is prevented by placing antibiotics directly in the newborn’s eyes

Answer 7

inclusion conjunctivitis

Question 8

this relatively uncommon but invasive Chlamydia trachomatis infection is characterized by lymphadenitis and small genital papules that may ulcerate

Answer 8

lymphogranuloma venereum

Note: chronically leads to lymphatic obstruction and elephantiasis

Question 9

this syndrome most frequently follows infection by C. trachomatis, and is a collection of symptoms including urethritis, conjunctivitis and arthrits

Answer 9

Reiter’s syndrome. Can’t pee, can’t see, can’t climb a tree. Also called reactive arthritis.

Question 10

Which of the following statements regarding Mycoplsamas is FALSE?

A. They are highly pleomorphic with no organized structure.

B. They lack cell walls.

C. They are spread by aerosols after a 2-3 week incubation period.

D. Include a strain that causes walking pneumonia.

E. They are most effectively treated with penicillin.

Answer 10

E.

Mycoplasmas have no cell walls and therefore are not sensitive to beta-lactam antibiotics like cephalosporin and penicllin. They require treatment with macrolides (azithromycin, erythromycin)

Question 11

Which of the following components of the chlamydia life cycle is incorrect?

A. small, condensed elementary bodies infect epithelial cells

B. elementary bodies adhere to epithelial cells and are endocytosed, where they give rise to an inclusion body

C. after ~ 24 hours, the elementary bodies enlage inside the endosome to become reticulate bodies.

D. after ~30 hours, the reticulate bodies begin to condense into new elementary bodies within the endosome

E. after ~36 hours, the endosome is lysed and the elementary bodies are released

Answer 11

C. This step takes place after about 8 hours.