Unit 1 - Gonorrhea and Chlamydia Flashcards
Neisseria gonorrhoeae bacteriology
G- diplococci with LOS
- human-restricted
- oxidase positive, not encapsulated, needs chocolate agar (not blood agar) as growth inhibited by trace metals and fatty acids
- very sensitive to dehydration, cold
- plasmid-borne Ab resistance is more common than in meningococcus (cephalosporin resistance emerging)
how are N. gonorrhea and N. meningitidis the same and different?
both
- human restricted, G- LOS diplococci
- oxidative positive
- cleared from bloodstream by immune complement
- growth in vitro inhibited by trace metals and FA (need chocolate, not blood, agar)
N. g
- not encapsulated
- hundreds of serotypes
- even more sensitive to dehydration, cold
N. m
-ferment maltose
N. gonorrhea pathogenesis
sexually transmitted or at birth
- genital tract infections most common, anorectal and pharyngeal also occur
- Ab, complement, and neutrophils are restricted to local infection site (vagina, urethra)
- bacteremia occurs in certain strains, predispositions
- extremely contagious sexually (single-exposure transmission)
- symptoms develop quickly (no latency)
what is the usually N. gonorrhea pathogenesis/exam for neonates, males, and females?
neonate: bilateral purulent conjunctivitis; if untreated, permanent blindness
male: usually symptomatic anterior urethritis
female: usually asymptomatic, cervicitis, purulent vaginal discharge, but type IV pili confer “twitching motility” for progression to PID
both: coinfection of pharynx, rectum, eye
virulence factors of N. gonorrhoeae
- IgA protease: clears IgA from mucosal surfaces for colonization
- pili: attach to columnar and transitional epithelium of mucosal surfaces, antiphagocytic
- Opa: opacity-associated proteins enhance cell adherence and entry
- porin A and B channels: in outer membrane, confer serum resistance and enhance cell entry
- LOS: less immunogenic than LOS, but induces local inflammatory response (irritation, discharge, containment)
is N. gonorrhoeae dependent on host for replication?
no, it’s replication-competent, so intracellular penetration is for immune evasion
describe pelvic inflammatory disease
-what is Fitz-Hugh-Curtis syndrome?
spread of cervical infection to fallopian tubes creates pain, risks of infertility, and ectopic pregnancy
- follows from mixing bacteria with refluxed menstrual blood or attachment to sperm (“twitching motility” by pili)
- intermenstrual bleeding, dysurea
- sonogram may show thick fallopian tubes or abscess
- FHCS: bacteria (gonorrhea or chlamydia) jump from tubes to liver capsule to cause acute perihepatis
what happens if bacteremia (dissemination) of N. gonorrhoeae occurs? predisposition?
- lack of urogenital symptoms
- arthritis/dermatitis (joint pain and skin pustules)
- septic asymmetric arthritis (knee common)
- asymmetric tenosynovitis with pain in wrists and akles - rarely meningitis, endocarditis
certain strains are more likely to disseminate
-more common in women, asymptomatic infection, menses, pregnancy, and C6-9 deficiency predispose
how common are gonococcal meningitis and endocarditis? info on them?
both are rare
- meningitis: spinal tap
- endocarditis: EKG, cardio consult (mostly in men)
- -aortic valve more common site
- -subacute onset of fever, chills, sweats, malaise, chest pain, cough
gonorrhea labs for males
urine and exudate testing for PMNs and intracellular diplococci
- if negative: urethral swab for G-, oxidase+, culture on Thayer-Martin agar
- most sensitive and specific method
gonorrhea labs for females
obtain endocervical smear (urethral sample if hysterectomy) but wife exudate off first
-culture on Thayer-Martin
gonorrhea labs for DGI (disseminated gonococcal infection)
- swab, gram stain, culture samples from all affected areas
- blood, joint fluid cultured on nonselective chocolate agar
- immunofluorescence may give better results than G stain or pustule samples
N. gonorrhea treatment
prompt antibiotics, before labs come back
- ceftriaxone, alternate cefixime, cephalosporin
- add azithromycin or doxycycline for coinfection with chlamydia
- aspirate septic joints
- admit if pregnant, PID, DGI, endocarditis, meningitis, purulent joint infection
what is expedited partner treatment?
provides scripts without exam for sexual partners of gonorrhea patients
C. trachomatis bacteriology
elementary bodies: dense, rugged, attach to cell, endocytosed, survive, and “unpack” into reticulate bodies
reticulate bodies: larger, delicate G- membrane, replicate, metabolize, “pack” into EBs, escape host cell
