Page 1 of 1: Micro - ? gonococcus?

simv · Credits: 3490 My Scrapbook

A 37-year-old woman presents with 3 days of progressive joint pain in
her ankles, knees, and wrists. She recalls three similar episodes over the
past several years. On examination, she has a temperature of 38.7 C, her
blood pressure is 110/70 mm Hg, and her heart rate is 90/min. She has a
diffuse petechial rash over her trunk and extensor surfaces. Her ankles
and knees are swollen, red, and tender with decreased range of motion,
and there is tenderness over the tendon sheaths of her hands and
forearms. Blood cultures are negative. Aspiration of joint fluid
reveals a white cell count of 22,000/mm3 with no visible organisms,
but culture on chocolate agar is positive. Which of the following
is an attribute of the causative organism that allows it to produce
recurrent infections?

A. It is an intracellular pathogen
B. It is resistant to ceftriaxone
C. It is resistant to complement-mediated lysis
D. Its capsule is not immunogenic
E. Its pili undergo antigenic and phase variation

thanks in advance...

if possible post along with explaination.

siv · Credits: 639 My Scrapbook

Hi simv,

I think the answer is Antigenic variation of outer membrane and pilli.

The organism described in N.Gonorrheae - causing Arthritis. This aspirate doesnt show any organism because it is a "reactive arthritis". The clue ot find the organism is - Arthritis + Chocolate Agar growth.

There is no vaccine for N.gonorrhea due to the fact that it undergoes antigen variation in its outer membrane and pilli.

Penicillin resistant strains are common due to beta lactamase production, hence the preferred drug of choiceis Ceftriaxone.

Hence, i conclude the answer is the variation feature of this organism.

Pls add other informations to this simv.

cheers
vinu

dr4jc · Credits: 4396 My Scrapbook

yes I agree with Siv that the ans is Neisseria gonorrhoea and the antigenic variation> 1 million (pili)variants..It doesnt have a capsule and therefore resistant to complement mediated lysis(which is an important feature in N.meningitidis)

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