Neisseria gonorrhoeae Flashcards

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1
Q

Neisseria gonorrhoeae

A

Neisseria gonorrhoeae

  • _Gram negative diplococcus (kidney-shaped cocci) *_
  • _Oxidase +, catalase + *_
  • _Breaks down only Glucose (Gonococcus) *_
  • Reservoir:
    • _Human genital tract (asymptomatic infected individuals) *_
  • Transmission:
    • Sexual contact
    • Neonates – during birth
  • Causes Gonorrhoea – a sexually transmitted disease (STD)
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2
Q

Gonococcus – Virulence factors *

(Neisseria Gram negative cocci)

A

Gonococcus – Virulence factors *

  • Pili – adherence and colonization *
  • Outer membrane proteins (OMP)
    • Opa and Porin proteins
    • adherence
  • IgA protease – imp. for colonization
  • Lipooligosaccharide (LOS) *
  • _Antigenic and Phase variation *_
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3
Q

Antigenic and Phase variation of Gonococcus *

(Neisseria Gram negative cocci)

A

Antigenic and Phase variation of Gonococcus *

  • Antigenic and Phase variation *
  • Each bacterium has the ability to express numerous different pili, it can change the pili at any time
  • The aminoacid sequences of the pili vary, therefore the pili are antigenically distinct
  • Each different pilus elicits a different antibody
  • During an infection Gonococcus can evade detection by the hosts’ immune system by changing the pili it expresses
  • it can also turn on or off the production of pili (phase variation)
  • Antigenic variation occurs with pili, OMP (outer membrane protein) and LOS (Lipooligosaccharide)
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4
Q

Antigenic variation of Gonococcus accounts for?

(Neisseria Gram negative cocci)

A

Antigenic variation of Gonococcus accounts for:

  • ** chronicity of infections ***
  • ** lack of protection against subsequent gonococcal infections**
  • Reason why both partners must be treated at the same time
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5
Q

Gonococcus – Disease spectrum

(Neisseria Gram negative cocci)

A

Gonococcus – Disease spectrum

  • Gonorrhoea – genito-urinary tract infection
  • In men:
    • _Urethritis *_
    • Epididymitis
    • Prostatitis
  • In women:
    • Urethritis
    • Endocervicitis *
    • Pelvic inflammatory disease (PID)
  • Rectal infections *
  • Pharyngitis *
  • Ophthalmia neonatorum *(neonatal conjunctivitis)
  • Disseminated infection
  • Septic arthritis *
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6
Q

Gonorrhoea – genito-urinary tract infection in men

(Neisseria Gram negative cocci)

A

Gonorrhoea – genito-urinary tract infection in men

  • _Urethritis *_
  • Epididymitis
  • Prostatitis
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7
Q

Gonorrhoea – genito-urinary tract infection in females

(Neisseria Gram negative cocci)

A

Gonorrhoea – genito-urinary tract infection

  • Urethritis
  • Endocervicitis *
  • Pelvic inflammatory disease (PID)
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8
Q

Gonorrhoea – genito-urinary tract infection in neonates

(Neisseria Gram negative cocci)

A

Gonorrhoea – genito-urinary tract infection in neonates

Ophthalmia neonatorum *(neonatal conjunctivitis)

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9
Q

Gonococcus - Urethritis in men

(Neisseria Gram negative cocci)

A

Gonococcus - Urethritis in men

  • Thick, yellow purulent exudate
  • (gram stain shows numerous PMNs (polymorphonuclear leukocytes) +GN diplococci)
  • Frequent, painful urination
  • Complications include epidydimitis and prostatitis
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10
Q

Gonococcus – Endocervicitis, Urethritis in females

(Neisseria Gram negative cocci)

A

Gonococcus – Genito-urinary tract infection in females with Endocervicitis, Urethritis in females

  • Purulent discharge (examine cervix)
  • Frequent, painful urination, lower abdominal pain
  • Approx. 50% cases go undetected
  • Complications include salpinigitis(infection and inflammation in the fallopian tubes. used synonymously with pelvic inflammatory disease (PID)) , Pelvic inflammatory disease (PID) and sterility
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11
Q

Rectal infections caused by Gonorrhoea

(Neisseria Gram negative cocci)

A

Rectal infections caused by Gonorrhoea

  • Prevalent in men who have sex with men (MSM)
  • painful defecation, discharge, constipation, proctitis (Inflammation of the anus and lining of the rectum)
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12
Q

Pharyngitis caused by Gonorrhoea

(Neisseria Gram negative cocci)

A

Pharyngitis caused by Gonorrhoea

  • Due to oral-genital contact
  • Mild to severe infection
  • Purulent exudate
  • Resembles “Strep” throat
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13
Q

Ophthalmia neonatorum

(Neisseria Gram negative cocci)

A

Ophthalmia neonatorum - cause by Gonorrhoea

  • Also known as Neonatal conjunctivitis (inflammation of the surface or covering of the eye).
  • Contracted by newborns during delivery
  • Redness, swelling of eye, purulent discharge
  • Rapidly leads to blindness if not immediately treated
  • Standard procedure in hospitals → administer antibiotic drops/ointment after delivery → Helps prevent eye infection (even if the mother shows no symptoms of infection)
  • _Chlamydia and N.gonorrhea are the most common STDs that cause septic neonatal conjunctivitis******_
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14
Q

The hell this baby got? What it’s caused by?

A

Ophthalmia neonatorum, caused by that younge Gonococcus (Gonorrhoea).

(Neisseria Gram negative cocci)

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15
Q

Gonococcemia

(Neisseria Gram negative cocci)

A

Gonococcemia

  • Disseminated infection - untreated infection which has invaded bloodstream
  • Rarely occurs (as most strains do not multiply in blood)
  • Also produces necrotic skin lesions on a erythematous base
  • Most commonly results in _septic arthritis *_
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16
Q

Septic Arthritis

A

Septic Arthritis (possible component in gonorrhoea infection)

  • Arthritis is inflammation of the joint
  • If caused by a pathogen → septic /infectious arthritis
  • When pathogen is bacterial→ bacterial/suppurative arthritis
  • Could result from hematogenous spread from another site of infection or
  • Direct infection of the joint (wound/penetrating injury)
  • Gonococcus is the most common cause of septic arthritis in the sexually active age group
  • Staph. aureus is the most common cause overall (in adults and children over 2 yrs)

(Neisseria Gram negative cocci)

17
Q

Gonococcus – Diagnosis

(Neisseria Gram negative cocci)

A

Gonococcus – Diagnosis

  • Genital disease
      • In males: urethral discharge
      • In females: endocervical swab
  • Gram stain
    • Of diagnostic value only in male patients *
    • Not useful for endocervial, throat and other specimens * (because some species of Neisseria are normal flora in the oro- and nasopharynx)
  • Culture
    • All specimens must be cultured to establish diagnosis
    • Thayer Martin media (chocolate agar with antibiotics to supress other bacteria – normal flora) *
    • Provide 5-10% CO2 *
  • Gene probes and PCR also available
  • _Patients with gonorrhea should be tested for Chlamydia trachomatis infection also (concurrent infection) *_
18
Q

Gonococcus – Treatment* *

(Neisseria Gram negative cocci)

A

Gonococcus – Treatment* *

  • 20% gonococcal isolates → resistant to penicillin, PPNG (penicillinase-producing N.gonorrhea) *
    • Beta-lactamase production
    • Changes in penicillin-binding proteins
  • Common resistance also to:
    • Tetracyclines, erythromycin and fluoroquinolones
  • Drugs of choice now:
    • Third generation cephalosporins - Ceftriaxone *
  • Due to the many cases of **co-existing infection with C. trachomatis **
    • Doxycycline is added to treatment regime *