Neisseria

Question 1

What are the symptoms of gonorrhoeae in men

Answer 1

•dysuria
•urethral discharge

Question 2

How does gonorrhoeae manifest in men

Answer 2

•colonises urethra
•incubation of 1-7 days
•transmitted by sexual contact
•95% show acute infection symptoms

Question 3

What are complications of gonorrhoeae in men

Answer 3

•epididymitis
•urethral stricture- narrowing of urethra
•prostatitis

Question 4

Treatment of gonorrhoeae in men

Answer 4

•antibiotics
•must notify close contacts

Question 5

How does gonorrhoeae manifest in women

Answer 5

•colonises endocervix
•20-80% asymptomatic

Question 6

What are gonorrhoeae symptoms in women

Answer 6

•burning or increased frequency of urination
•vaginal discharge
•abdominal pain
•bleeding
•fever

Question 7

Gonorrhoeae complications in women

Answer 7

•pelvic inflammatory disease (PID)
•ascending infection into fallopian tube tubes -> sterility and ectopic pregnancy
•perihepatitis- scar tissue around liver due to chronic inflammation

Question 8

Therapy to treat gonorrhoeae in women

Answer 8

•antibiotics
•cant prevent PID

Question 9

Disseminated gonococcal disease

Answer 9

Acute form
•fever, chills, malaise, intermittent bacteremia, skin lesions
•progresses to septic joint

Gonococcal arthritis
•chronic immune response to disseminated gonococcal bacteremia

Question 10

Gonorrhoeae in children

Answer 10

•ophthalmia neonatorum (eye infection)
•occurs during vaginal delivery
•infection preventable with eye drops (erythromycin or silver nitrate)

Question 11

Extragenital infections

Answer 11

•pharyngitis
•anorectal infection
•30-60% of women with genital infection also have anorectal
•also gay men

Question 12

Specimens to diagnose gonorrhoeae

Answer 12

•swabs from genitals- urethra in men, endocervix in women
•swabs from anus, pharynx, eye, blood, joints

Question 13

Media for gonorrhoeae

Answer 13

•transport media: transgrow, JEMBEC, Amies medium

Thayer Martin (MTM) agar
•chocolate agar (lysed blood)
•vancomycin (inhibits gram pos)
•colistan (inhibits other gram neg)
•nystatin (inhibit fungi)

•small, grey, translucent raised colonies

Question 14

Morphology of gonorrhoeae

Answer 14

•gram negative
•kidney bean shaped diplococci
•verify with penicillin disk test

Question 15

Multi drug resistance (MDR)

Answer 15

•resistance to 1 recommended drug
(cephalosporin OR azithromycin)
•PLUS resistance to 2 other drugs
(penicillin, tetracycline, erythromycin, ciprofloxacin)

Question 16

Extreme drug resistance (XDR)

Answer 16

•resistance to 2 recommended drugs
(cephalosporin AND azithromycin)
•PLUS resistance to 2 other drugs

Question 17

How is antibiotic resistance caused in gonorrhoeae

Answer 17

•point mutation on chromosome
•acquisition of resistance markers by natural transformation for commensal Neisseria species

•not many horizontally acquired elements (plasmids or transposons)

Question 18

Sulphonamides for gonorrhoeae

Answer 18

•over synthesis of para-aminobenzoic acid

•chromosomal mutation in dihydropteroate synthetase- prevents binding by sulphonamides

•no plasmid mediated resistance

Question 19

Quinolones for gonorrhoeae

Answer 19

•chr mutation in gyrA and parC (DNA replication)
•no plasmid mediated resistance

•recommended in areas where 95% of isolates are susceptible

Question 20

Macrolides for gonorrhoeae

Answer 20

•chr mutation in 23S rRNA rrl to prevent antibiotic binding to ribosome

•chr expression of ermB, ermC and ermF methylase encoding genes
•methylate target 23S rRNA to prevent binding by antibiotic

•mutations in mtrR increase efflux from MtrCDE pump

Question 21

MtrR

Answer 21

•repressor of transcription of multidrug efflux pump, MtrCDE
•mutation results in high constitutive expression of pump thus, increased drug resistance

Question 22

MtrCDE

Answer 22

•ABC transporter for removal of drugs
•Pmtr= promoter of MtrCDE which is repressed by MtrR in absence of drugs
•mutation of promoter of MtrR itself relieves repression and results in high constitutive expression of pump

Question 23

Penicillin and cephalosporin are both

Answer 23

Beta lactams

Question 24

Tetracyclines for gonorrhoeae

Answer 24

•chr mutations in rpsJ (30S ribosomal protein S19) exclude binding to ribosome
•penB to exclude antibiotic
•mtrR promoter and gene efflux antibiotic
•plasmid mediated production of TetM protein

Question 25

Spectinomycin for gonorrhoeae

Answer 25

•chr mutations in spc locus (rRNA genes) •plasmid mediated resistance is rare •not recommended as first line due to ease of resistance •2nd or 3rd line agent

Question 26

Aminoglycosides for gonorrhoeae

Answer 26

•chr mutation in kan gene •no plasmid mediated resistance •not recommended as first line

Question 27

Vaccines against Neisseria are difficult to design

Answer 27

•gonorrhoeae is naturally transformable •antigenic variation •genetic drift of immunogenic strains results in strain-specific immunity •gonorrhoeae suppresses B and T cell response

Question 28

Other options against gonorrhoeae

Answer 28

•early intervention to prevent transmission •pre-exposure prophylaxis (PreP)

Question 29

Rational drug design

Answer 29

•identify drug targets •target should be essential for bacterial replication and host survival •examine whether virulence determinant is unique to bacterium or enables selective inhibitors •solve crystal structure of protein and look for inhibitors

Question 30

Phosphoethanolamine (PEA) transferases (Ept)

Answer 30

•EptA adds phosphoethanolamine to lipid A •adds it to the headgroup in periplasm of gram neg EptA required for: •resistance to cationic antimicrobial peptides (CAMPs) •resistance to complement mediated lysis •attachment to host cells

Question 31

What are some examples of CAMPs

Answer 31

•cathelcidins •human beta-defensins •theyre both positively charged and bind to negative charges on bacteria

Question 32

How does EptA help bacteria

Answer 32

•removes negative charges on the membrane •CAMPs can no longer bind and work •bacteria resistant to killing, establish infection

Question 33

Which immune cells first respond to gonococcal attachment

Answer 33

•Th-17 neutrophils