3rd Lecture: Gonorrhea and Chlamydia Flashcards Preview

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What are the 6 learning objectives of this lecture?

1. Describe gonococcus and Chlamydia transmission and disease
2. Compare/contrast LPS and LOS
3. Discuss appropriate agar media for Neisseria in vitro.
4. Differentiate intracellular from extracellular bacterial infection.
5. Describe Chlamydia's unique life cycle (elementary & reticulate).
6. Cite the common effective measures for treatment and prevention of both these STIs.


What are the 8 characteristics of N. gonorrhoeae (gonococcus)?

1. Gram negative diplococci
2. Human-restricted
3. Oxidase positive
4. Won't grow on blood agar, use chocolate agar or Thayer-Martin as appropriate
5. NOT encapsulated
6. Hundreds of serotypes
7. Very sensitive to dehydration, cold
8. Plasmid-borne Ab resistance more common than in meningococcus, cephalosporin resistance emerging right now


What are the 2 modes of transmission of
N. gonorrhoeae?

It can be transmitted either sexually or via birth


What are the three ways that N. gonorrhoeae use to accomplish it's pathogenesis?

1. Pili
2. IgA protease
3. Opa virulence factors


(Kaplan) What are the roles of Pili?

1. Attachment to mucosal surface
2. Inhibit phagocytic uptake
3. Antigenic (immunogenic) variation: over 1 million variant


(K) What is the role of IgA protease?

Aids in colonization and cellular uptake


(K) What is the role of Opa proteins?

Antigenic variation, adherence


What is the role of porin A and B?

Confer serum resistance in strains that are more likely to disseminate (Disseminated Gonococcal Infection)


In case of male, is N. gonorrhoeae usually symptomatic?

Yes, anterior urethritis


In case of female, is N. gonorrhoeae usually symptomatic?

No, it's often asymptomatic (However, it can cause cervicitis, Type IV pili confer "twitching motlity" --> progression to PID)


In case of neonate, what does N. gonorrhoeae cause?

Purulent conjunctivitis


True or False
Unlike syphilis, the symptoms develop quickly (no latency)



During the exam, what can be observed from a male pt who has N. gonorrhoeae?

1. Urethritis
2. Dysuria
3. Purulent discharge


During the exam, what can be observed from a female pt who has N. gonorrhoeae?

1. Purulent vaginal discharge
2. PID: pain, bleeding, perihepatitis, thick Fallopian tubes or abscess on sonogram


What symptoms are seen from both sex?

Coinfection of pharynxy, rectum, eye may occur


What can disseminated infection cause?

1. Lack of urogenital symptoms
2. Arthritis/dermatitis
3. Septic arthritis
4. Rarely meningitis, endocarditis


What can N. gonorrhoeae cause in neonate?

bilateral conjunctivitis, if untreated permanent blindness


What are the labs you need to do for male pt?

1. First, test urine and exudate for PMNs and intracellular diplococci
2. If needed, obtain urethral swab for Gram stain, culture on Thayer-Martin agar


What are the labs you need to do for female pt?

Obtain endocervical smear, culture on Thayer-Marin


What are the labs you need to do for disseminated gonococcal infection?

1. Gram-stain, culture sample from all affected areas
2. Blood, joint fluid may be cultured on nonselective chocolate agar


When should the treatment for gonococcal infection begin?

Begin antibiotics before labs come back


What are the drugs needed to treat gonococcal infection?

1. Ceftriazone, alternate cefixime, cephalosporin


When treating gonococcal infection what other drugs do you need to add?

Add azithromycin or doxycycline for coinfection with Chlamydia


What is a prevention for neonatal dz due to gonococcal infection?

erythromycin ointment on eyes at birth


What is unique about C. trachomatis?

It has unique life cycle:
1. dense, rugged elementary bodies (EBs) attach to cell, endocytosed, survive, "upack" into reticulate bodies
2. larger, delicare, RBs replicat, metabolise, pack into EBs, escape host cell


What form of C. trachomatis is only infectious?

elementary bodies (reticulate bodies only divide)


How are symptoms of genital Chlamydia trachomatis determined?

by serovar (serotype)


What are the serotypes of C. trachomatis that causes blind?

A, B, Ba, C


serotypes A, B, Ba, C of C. trachomatis cause

1. a leading preventable blindness
2. spread by secretions, fomites
c. endemic to Africa, southern Asia


What serotypes cause lymphogranuloma venereum?

1. L1-L3