bacterial STIs Flashcards
differentiate between STDs and STIs
STI
—- a pathogen that causes infection thru sexual contact
STD
—- a recognizable disease state that has developed from an infection
what are the most common STIs?
HIV, HPV, Hepatitis virus, neisseria gonorrhoeae, chlamydia trachomatis, and treponema pallidum
how long has been syphilis been around? who introduced the term of syphilis?
since 3000 BC – it’s an old disease
aka “the stranger disease” aka venereal pest
term introduced by Girolamo Fracastoro in a poem
who discovered the etiologic agent behind syphilis? when was the first tested for?
schaudinn and hoffman in 1905
the first serologic test for syphilis was conducted in 1910 – called the wasserman test
the first specified test for T. pallidum was conducted in 1949 – called the immobilization test
what bacteria caused syphilis?
treponema pallidum
who discovered the treatment for syphilis? what was it?
Paul Ehlrich discovered compound 606 (salvarsan arsphenamine, a derivative of arsenic) as treatment for syphilis — toxic!!
another treatment was the injection of mercury into the urogenital tract – not used anymore, this was in the past
describe the Tuskegee Syphilis Study
from 1932 to 1972 in Alabama
600 participants
28 died from syphilis
100 died of related complications
black participants were not told what it was – unethical
what causes gonorrhea? when was it first identified? what decreased the incidence of gonorrhea?
neisseria gonorrhoeae
some manuscripts from 1st century BC identified gonorrhoia as an established disease in ancient greece
Albert Neisser discovered the causative agent in 1879
apparition of sulfonamides decreased the incidence of gonorrhea
describe chlamydia’s history
it was a hidden disease under gonorrhea and syphilis infection
in 1930s, appearance of a chronic non-specific venereal disease
in 1972, Eric Dunlop’s work was the first to identify chlamydia trachomatis as the cause of this bacterial genital infection
what causes chlamydia?
chlamydia trachomatis
what’s the most common bacterial STI?
chlamydia trachomatis
since the late 1990s
what does a bacterial STI being an obligate pathogen mean?
the microbes have no other niche than the human body – they require human-human contact for transmission
describe treponema pallidum, what type of bacteria is it? how is it transmitted?
gram-, spirochetes (more spirals than usual spirillum)
transmitted sexually or from mother to child
why is treponema pallidum unculturable?
sensitive to oxygen – dies when experiencing atmospheric oxygen concentrations
does not tolerate desiccation (removal of moisture)
sensitive to high temperatures
what are the stages of syphilis (treponema pallidium) and when do they occur?
stage 1 (3-90 days after exposure)
— sores/ulcers in mouth or genitals
stage 2 (4-10 weeks after exposure)
— body rash, which is easily recognized
— more apparent, more marks over body
stage 3 (3-15 years after exposure)
— affects internal organs with no external signs
— not contagious anymore! considered latent
how many treponema pallidum cells are required to transmit the syphilis disease? what is its virulence factor?
as few as 10 cells
internal flagella which can’t be recognized
outer membrane proteins which allow it to attach to the epithelial cells and extracellular matrix
can evade immune response by changing the TprK protein through antigenic variation
how is treponema diagnosed?
PCR
serologic tests
what’s the treatment for treponema?
no vaccines are available
but there are antibiotic treatments
— penicillin or doxycycline/ceftriaxone
describe neisseria gonorrhoeae, what type of bacteria is it? how is it transmitted?
gram-, diplococci
—– it’s non-motile (can’t move by itself) and an obligate human pathogen
transmitted sexually or from mother to child
unviable to non-physiological changes – sensitive to environments different from what it’s used to – so it needs to be in your body to function
describe the disease of gonorrhea
usually asymptomatic in females and symptomatic in males
males will have discharge from the penis, yellow ish and swollen testicles, inflammed penis, UTI
females could also have abdominal pains, discharge and vaginal bleeding between periods
both will have panful urination
what does neisseria gonorrhea cause?
gonorrhea, a STD
can also cause gonococcal conjunctivitis which is a type of pink eye
describe the cycle neisseria gonorrhoeae takes?
it first adheres to the urogenital tract’s epithelium
it competes with resident microbiota, acquires nutrients, and forms microcolonies – then colonizes and invades the epithelium
releases peptidoglycan, LOS (cell wall antigen), OMVs that activate epithelial cells, macrophages, and DCs
the neutrophil-rich pus facilitates transmission from the urogenital tract -> out
what virulence factors does neisseria gonorrhoeae have?
type IV pili
Opa (opacity proteins)
cell wall antigen (LOS)
PorB (OM porin)
—— can prevent complement activation, opsonization, and bacterial killing
how is neisseria gonorrhoeae diagnosed?
PCR
culture
how is neisseria gonorrhoeae treated?
no vaccine available
lots of antibiotic resistance present (Motor efflux pump, expulsion of antibiotics from intracellular environment of bacteria)
——- urgent need for new therapeutics
last resort: cephalosporin (cefixime)
—- generally not used to avoid creating resistant strains
describe chlamydia trachomatis, what type of bacteria is it? how is it transmitted?
gram- (thin or no peptidoglycan layer)
obligatory intracellular pathogen!
transmitted sexually or from mother to child
describe the symptoms of chlamydia
generally asymptomatic in both women and men – explains its success
for both: inflammation, discharge
in females: infertility or ectopic pregnancy and prolonged menses
describe the life cycle of chlamydia trachomatis (update this)
elementary body
— infectious contagious stage
— can attach and enter as an endosome
— differentiates into initial RB body
reticulate body
- after 12 hours, binary fission and inclusion growth, two options from here
— reticulate body association with inclusion membrane, eventually differentiates to elementary body
— persistent form, reactivates into reticulate body or in some cases, reactivates into elementary body
- after 40-48 hours of elementary body accumulation, the inclusion exocytosis releases elementary bodies
differentiate between elementary and reticulate bodies in regards to chlamydia
elementary body is infectious
reticulate body allows for multiplication
what are the virulence factors of chlamydia trachomatis?
LPS = presumably bind to CFTR (receptor found at surface of genital epithelium)
major outer membrane protein (MOMP)= bind to mannose receptors of human host cells (epithelium)
secretion systems (T3SS,T2SS,T5SS)
—– helps manipulate epithelial cells, allowing bacteria to carry out its life cycle
—– “type 3 secretion system”, etc.
how is chlamydia trachomatis diagnosed?
PCR
culture
how is chlamydia trachomatis treated for?
no vaccine available
antibiotic treatment
— azithromycin (macrolide)
— doxycycline (tetracycline)
