14 Neisseria gonorrhea & Chlamydia Flashcards
What disease is the second most commonly reported infectious disease in the US with >330,000 cases in 2012?
Neisseria gonorrhea
What disease is the first most commonly reported infectious disease in the US with 1.4 million cases in 2012?
Chlamydia
What is the mode of transmission for N. gonorrhea? Environmental Human-human Insect-borne Animal-human
Human-human ONLY
What are the hallmark signs of N. gonorrhea?
Inflammation and purulent discharge from a mucosal surface
What mucosal surfaces can be involved in a N gonorrhea infection?
throat, anal, eyes of infants, male urethra, female cervix mucosa
What are the sx of gonorrhea urethritis in males?
Does the male seek treatment?
extensive urethral discharge
dysuria
rare complications
Yes, infected male seeks treatment 2-5 days after the sexual encounter
What are the sx of gonorrhea infection in females (gonorrheal cervicitis)?
generally none - if symptoms, variable Possibly: abdominal pain cervical discharge dysuria intermenstrual bleeding
What is the chance of an uninfected female engaging in genital sex with an infected male becoming infected?
50-73%
What is the chance of an uninfected male engaging in genital sex with an infected female becoming infected?
20%
Which portion(s) of the female reproductive tract are initially infected with N. gonorrhea?
Only the cervix (columnar epithelial cells)
Not the vaginal mucosa
What is the danger of untreated gonorrhea & Chlamydia in females?
Gonorrhea: What percentage of infected, untreated females have complications?
It ascends into the uterus and fallopian tubes (salpingitis)
PID (pelvic inflammatory disease), possibly causing fallopian tube scarring and/or persistent pelvic pain
10-20%
Define salpingitis:
inflammation of the fallopian tubes
What are the potential complications of damaged fallopian tubes?
infertility & ectopic pregnancy
What can happen if N. gonorrhea enters the blood stream? (systemic infection complications)
septic arthritis - fever, migratory arthralgiaas, reddened pustular lesions on extremities, petechiae
gonococcal meningitis
endocarditis
What is the most common cause of infectious arthritis in sexually active adults?
Septic arthritis caused by N. gonorrhea
Who is more susceptible to systemic complications of N. gonorrhea?
females
patients with late complement protein deficiencies
Define ophthalmia neonaturum:
When does it develop?
Purulent conjunctivitis leading to blindness if untreated
Develops 5 days after vaginal birth to a gonococcal-infected mother
What is the prophylaxis treatment for ophthalmia neonaturum?
When is it given?
Eye drops of erythromycin/neomycin administered within minutes after birth
What is happening during much of the incubation period for N. gonorrhea? How is it getting into the body? Where does it replicate?
Pili and other proteins allow them to adhere to non-ciliated epithelium
They trick epithelial cells to take them up into intracellular vesicles and then exit out the basolateral surface
Bacteria replicate in the sub-epithelial space
Bacteria replicating in the sub-epithelial space elicit what response? To what part of the bacterium?
They elicit a characteristically exuberant PMN response in response to LOS
What 5 virulence factors does N. gonorrhea use to survive PMN killin?
- Opa (opacity protein) mediates firm attachment to epithelial cells and invasion into cells
- Outer membrane porin (Por) prevents phagolysosome fusion following phagocytosis -> promoting intracellular survival
- Rmp is an outer membrane protein that blocks bactericidal antibodies directed against Por and LOS
- Other surface features block or cleave antibodies
- Iron binding systems steal iron from lactoferrin, transferrin, and hemoglobin to overcome host’s nutritional immunity
If untreated, how long will N. gonorrhea infections persist?
months even after antibody titers reach high levels
How can N. gonorrhea persist for months even with high antibody titers?
Antigenic diversity: has numerous strategies for hypervariability of surface proteins (e.g. 1 in 100-10,000 bacteria make a novel pilin variant -> keeps gc ahead of immune system)
How is gonorrhea diagnosed in symptomatic males?
G- dipplococci observed in purulent discharge from the urethra (Gram stain)
can plate on chocolate agar for culture
How is gonorrhea diagnosed in females?
Because of complex vaginal flora, requires more than Gram stain
Streak cervical specimen onto Thayer-Martin agar (chocolate agar + antibiotics that select against normal vaginal flora) & plain chocolate agar
Diagnosis made by culture of bacteria on selective media
What is the alternative lab procedure for diagnosis of gonorrhea in males or females?
PCR assay that identifies gc-specific DNA
What are the pros/cons of PCR DNA assay over culture for gonorrhea diagnosis?
DNA assay faster than culture
DNA assay less invasive because can be conducted from urine specimen
DNA assay able to avoid fragile gc dying during specimen transport
Downside: DNA assay has no antibiotic sensitivity determinations; culture does
Gonorrhea treatment?
Penicillin no longer effective because of beta-lactamase prevalence in last 30 years
Cephalosporins (ceftriaxone - 3rd gen broad spectrum) is effective
If gonorrhea is diagnosed and removed but the symptoms remain, what is likely the problem?
there was an underlying Chlamydia problem that goes undiagnosed until the gonorrhea is removed. If not treated quickly, complications can arise
What is the antibiotic treatment of a Chalmydia infection?
If Chlamydia trachomatis has not been ruled out, azithromycin or doxyxycyclin is also used
What are 4 options for gonorrhea prevention?
No vaccine - hypermutable surface antigens
Barrier contraception - condoms + nonoxynol-9 containing spermicide
Abstinence
Wholly monogamous relationships
What are the lab characteristics of Chlamydia?
obligate intracellular parasite
non-motile G- bacteria
Being an intracellular parasite, Chlamydia relies on host machinery for what metabolism?
Rely on host enzymes to provide many amino acids and other building blocks
STEAL ATP from the host cell
What is present on the outer membrane of human-specific Chlamydia?
LPS and lipid A but very little to no peptidoglycan
What is the name for the active replicating form in the Chlamydia life cycle?
Reticulate body (RB)
What is the name for the inactive, non-replicating infectious form of Chlamydia?
Elementary body (EB)
Does Chlamydia cause acute or chronic infections?
both :)
Which is resistant to harsh conditions?
reticulate body
elementary body
elementary body
Which of these species are in the genus Chlamydia and which are in Chlamydophilia?
C. trachomatis
C. psittaci
C. pneumoniae
Chlamydia trachomatis
Chlamydophilia psittaci
Chlamydophilia pneumoniae
Which is responsible for STDs, conjunctivitis, lymphogranuloma venereum, trachoma, infant pneumonia?
C. trachomatis
C. psittaci
C. pneumoniae
C. trachomatis
Which is responsible for bronchitis, sinusitis, and primary atypical pneumonia syndrome while also being linked to atherosclerosis?
C. trachomatis
C. psittaci
C. pneumoniae
C. pneumoniae
Which is responsible for severe influenza-like disease from psittacine birds (ornithosis or parrot fever)?
C. trachomatis
C. psittaci
C. pneumoniae
C. psittaci
What is the most common bacterial sexually transmitted infection in the US and the most common cause of preventable blindness in the world?
C. trachomatis
What infections are at peak incidence at ages 18-24?
gonorrhea & Chlamydia trachomatis
What Chlamydia trachomatis serovars cause STDs?
D-K
What is the diagnosis of nongonococcal urethritis in men? How often is it asymptomatic?
lack of pink diplococcic in Gram stain of exudate
Asymptomatic in at least 1/3 of males
How does postgonococcal urethritis develop? When?
In men who are treated with antibiotics for diagnosed gonorrheal urethritis
2-3 weeks post-treatment of gonorrhea, Chlamydia becomes evident
What signs/symptoms are present in mucopurulent cervicitis?
What is the complication if left unchecked?
No obvious symptoms
Careful speculum exam shows yellow mucopurulent discharge in 30-50% cases
Can progress to PID
What bacterium can cause urethral infections in sexually active women, epididymitis, Reiter’s syndrome?
Chlamydia trachomatis
What is epididymitis?
Unilateral scrotal pain, fever, epididymal tenderness or swelling
Most common local complication of Chlamydia trachomatis infection
What is Reiter’s syndrome?
immune mediated disease: 3 combined conditions:
- urethritis
- arthritis
- conjunctivitis
What infection is found in newborns delivered vaginally by C. trachomatis-infected mothers?
conjunctivitis or TRIC (trachoma inclusion conjunctivitis) - profuse mucopurulent discharge
followed by neonatal afebrile pneumonia
How is adult inclusion conjunctivitis contracted by adults? Severity?
transmitted thru hand-to-eye spread of infected genital secretions (Chlamydia trachomatis)
rarely leads to blindness (milder than trachoma)
Define lymphogranuloma venereum:
rare disease in US
transient, painless papule or vesicle on any part of genitals; may rarely ulcerate. painful, multiocular suppurative lymphadenopathy, fever, headaches, conjunctivitis, skin rashes, nausea vomiting
What is the treatment for Chlamydia trachomatis infection?
little protective immunity
no acquired antibiotic resistance
most infections treated with tetracycline/doxycycline or macrolides (erythromycin for neonatal infections or azithromycin)
What are the recommendations on intercourse while treating C. trachomatis?
treatment of sexual partner key
abstain from intercourse for 7 days after therapy has begun
What is the SAFE strategy?
Surgery for deformed eyelids, Azithromycin; Face washing and Environmental improvements
Blindness prevention public health effort
Chlamydophila pneumonia diagnosis:
treatment?
difficult, tissue culture not routinely used
retrospective diagnosis
treatment: tetracycline or erythromycin
Who are most at risk for a C. psittaci infection?
Mode of transmission
people who work with birds or at a poultry slaughter house
Generally acquired from birds via respiratory route
Psittacosis is:
pneumonia with systemic manifestations (fever, headache, etc); spread to liver, spleen, heart, kidney
