Topic 1-10 (Lecture 10)

Question 1

Where does N. gonorrhoeae adhere to?

Answer 1

Genitourinary tissue (genitals and urinary organ tissues)

Question 2

How do N. gonorrhoeae attach to tissue?

Answer 2

Pili and surface proteins

Question 3

What are pili made of ?

Answer 3

PilE proteins or pilin

Question 4

How does N. gonorrhoeae cause its symptoms?

Answer 4

Attaches to epithelial cell, transcytoses through the cell into subepithelial space where a inflammatory response is induced (and cause the symptoms)

Question 5

What are opacity-associated proteins (Opa proteins) and their function in N. gonorrhoeae?

Answer 5

They are outer membrane proteins thought to be involved in adherence, and potentially aid in the ability of N. gonorrhoeae to invade host cells

Question 6

What is antigenic variation?

Answer 6

Method in which bacteria can rearrange genes in its DNA to change the structure of surface molecules to avoid antibodies

Question 7

What part of the pilin is highly conserved in N. gonorrhoeae?

Answer 7

The N-terminal Region

Question 8

What is pilE? What is pilS?

Answer 8

pilE = "pilin expression locus"
pilS = "silent (non-functional loci" (variant encoding gene)

Question 9

How does antigenic variation occur in N. gonorrhoeae?

Answer 9

pilS gene is transferred, in whole or in small stretches, into the pilE gene through homologous recombination which results in a chimeric pilin (formed from multiple different genes)

Question 10

How many variants of pili can be made using antigenic variation?

Answer 10

~ 1 million different antigenic variants

Question 11

How many copies of pilC genes does N. gonorrhoeae have?

Answer 11

2

Question 12

What is the role of pilC?

Answer 12

Necessary for assembly and maturation of the pili

acts as an adhesin

Question 13

How many copies of Opa genes does N. gonorrhoeae have?

Answer 13

10+

Question 14

What does the different Opa genes allow N. gonorrhoeae to do?

Answer 14

Allows adherence to a variety of cell types

Question 15

What happens if a mutant lacks Opa proteins?

Answer 15

They are unable to be engulfed by neutrophils

Question 16

What is an immunodominant protein? (ex. of such protein is the pili)

Answer 16

A protein that is targeted by antibodies (not all antigenic peptide products produced by a bacteria are targeted; immunodominant proteins are the few proteins that are targeted)

Question 17

How many pilS genes do N. gonorrhoeae have?

Answer 17

10 to 15

Question 18

What is phase variation?

Answer 18

The process of turning on or off the expression of a particular gene product

Question 19

How does N. gonorrhoeae use phase variation to evade host defences?

Answer 19

They vary their expression of pili by varying pilE expression. Opa is also varied as none, one, or several different types of opa proteins can be expressed at a given time

Question 20

What is the full name of N. gonorrhoeae?

Answer 20

Neisseria gonorrhoeae

Question 21

What are the general properties of N. gonorrhoeae?

Answer 21

Non-motile (doesn't move)
Non-sportulating (don't form spores)
Gram-negative (has double membrane & LPS)
Cocci (coccus, round in shape)
Found in pairs (diplococcus, two cocci)

Question 22

How are N. gonorrhoeae transmitted?

Answer 22

Transmission through contact (cannot survive in environment) via mucous membranes of genitourinary tract
Sexually transmitted infection (STI)

Question 23

What are the major virulence factors of N. gonnorhoeae?

Answer 23

Adhesins
Antigenic variation
Resistance to killing action of MAC
Iron acquisition

Question 24

What is the disease caused by N. gonorrhoeae and which specie(s) does it effect?

Answer 24

Gonoorrhea (asymptomatic infection possible)

Affects humans only

Question 25

How does N. gonorrhoeae affect men and when do those symptoms occur?

Answer 25

Cause urethritis (inflammation of the urethra)
Can cause painful/difficult urination, urethral discharge of pus
Appear 1-14 days after infection
Asymptomatic infections are POSSIBLE

Question 26

How does N. gonorrhoeae affect women and when do those symptoms occur?

Answer 26

Infection in the endocervix (mucous membrane lining cerivcal canal), possible urethra as well

Symptoms:
Cervical-vaginal discharge
Painfal/difficult urination
Abnormal/inter-menstrual bleeding
Absnormal/pelvic pain

Appear 7-21 days after infection
Asymptomatic infection possible

Question 27

What are possible complications of gonorrhea?

Answer 27

In women PID (Pelivc inflammatory disease)
-Cause sterility and possibly chronic pelvic pain

Gonococcal arthritis

Question 28

How does N. gonorrhoeae cause disease?

Answer 28

Causing inflammatory response AND avoiding immune response via antigenic variation

Question 29

How is N. gonorrhoeae treated?

Answer 29

Treatment with antibiotics

IF not treated, often clear within 6 months (i.e. self-limiting infection; a disease with a definite and limited course)

Question 30

What is opthalmia neonatorum and how is it prevented?

Answer 30

A disease cause by infection of the eyse of a newborn infant by N. gonorrhoeae transmitted by mothers during birth.

Prevented w/ routine use of antibacterial eye drops

Question 31

What are three techniques used to diagnose gonorrhea?

Answer 31

DNA - Detect presence of bacterial genes in urine samples or cervical swabs

Culture - incubation of the discharge, then perform biochemical tests/study cell and colony morphology to ID

Microscopy - Take discharge sample and stain using gram stain. Presence of gram-negative diplococci indicate gonorrhea typically (gram-negative diplococci are NOT normally present in microbiota)

Question 32

What antibiotics are used to treat N. gonorrhoeae?

Answer 32

Current option is treatment with cephalosporin and azithromycin

Question 33

Why are penicillin and tetracycline not used today to treat gonorrhea?

Answer 33

Bacterial resistance gained by plasmids encoding resistance

Question 34

Is there acquired immunity after N. gonorrhoeae infection?

Answer 34

NO

Question 35

Why is developing a vaccine for N. gonorrhoeae so difficult?

Answer 35

Antigenic varition of pilin

Lack of suitable animal model

Question 36

How is N. gonorrhea infections prevented?

Answer 36

Condom use
Contact tracing (so identifying people with the disease to prevent its continued spread)