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Micro - Neisseria Species (i) (N Gonorrhoeae (the gonococcus) (causes…
Micro - Neisseria Species (i)
intro
most are commensal in upper resp tract (e.g. N mucosa + N subflava)
grow well on blood agar
contribute to immunity against N meningitides (cross-reactive Igs)
some are pathogenic (N gonorrhoeae + N meningitides)
fastidious (esp N gonorrhoeae), require chocolate/NYC agar, dry out + die quickly, prompt transport to lab required
gram -ve diplococci
kidney/coffee bean shaped
intracellular
Aerobic + require CO2
Meningitis B vaccine in Ire for babies since 2016, but no catchup programme
place/white/translucent colonies
N Gonorrhoeae (the gonococcus)
Supergonorrhoea
resistant to 1st line Tx (ceftriaxone)
2nd most common bacterial STI
human only pathogen
readily transmitted by sexual contact (esp in gay men)
direct contact with mucous membranes (either sexual or perinatal)
causes infection of mucous membranes
sexual acquisition
urethral (men)
cervical
15% progress to PID + blockage of fallopian tubes
tubal infertility (esp in developing countries)
increased ectopic pregnancy risk
associated abdominal pain (frequent cause of hospital admissions)
rectal
pharyngeal
disseminated (uncommon)
associated with particular subtypes
more common in those with complement deficiencies + pregnant
BSI, septic arthritis
may be asymptomatic
esp in females
easier to spread
reinfection common due to lack of protective immunity
increased risk in those with complement deficiencies
in Ire affects men (esp 20-30 y/o) more than women
purulent
perinatal acquisition
ophthalmia neonatorum (purulent neonatal conjunctivitis)
presents 2 days after birth (up to 7 days)
disseminated (uncommon)
due to untreated gonorrhoea in pregnancy
also increased risk of chorioamnionitis
male symptoms
urethritis
epididymitis (most likely to occur)
dysuria
purulent discharge
female symptoms
often none
cervicitis
vaginal discharge
virulence factors
pili + fimbriae
resist phagocytosis by producing IgA proteases
outer membrane proteins
LOS
LOS Rs on urethral epithelial cells + sperm cells
Lab Dx
culture based
day 1
swab infected site
depends on patient's sex practices
blood + knee aspirate if disseminated infection suspected
give empiric antibiotics
do gram stain + place on agar plates
day 2
ID grown organism via biochem tests or MALDI-TOF
susceptibility testing
day 3
results of susceptibility tests - alter Tx if needed
PCR
used as test-of-cure
1-2 wks after Tx
can also ID
same day result
if a person has 1 STD they could have more - further testing
advice regarding future prevention Nb (education on condom use)
Tx
empiric
single dose IM ceftriaxone AND single dose oral azithromycin
disseminated infection
initially IV ceftriaxome
narrower spectrum antibiotic for 1 wk once susceptibility test result available
ophthalmia neonatorum
hospitalisation + IV antibiotics
prophylaxis in some countries: eyedrops for all neonates
best = tx affected mum while still pregnant
no vaccine :unamused: