bacterial STIs

Question 1

differentiate between STDs and STIs

Answer 1

STI
—- a pathogen that causes infection thru sexual contact

STD
—- a recognizable disease state that has developed from an infection

Question 2

what are the most common STIs?

Answer 2

HIV, HPV, Hepatitis virus, neisseria gonorrhoeae, chlamydia trachomatis, and treponema pallidum

Question 3

how long has been syphilis been around? who introduced the term of syphilis?

Answer 3

since 3000 BC – it’s an old disease

aka “the stranger disease” aka venereal pest

term introduced by Girolamo Fracastoro in a poem

Question 4

who discovered the etiologic agent behind syphilis? when was the first tested for?

Answer 4

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

Question 5

what bacteria caused syphilis?

Answer 5

treponema pallidum

Question 6

who discovered the treatment for syphilis? what was it?

Answer 6

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

Question 7

describe the Tuskegee Syphilis Study

Answer 7

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

Question 8

what causes gonorrhea? when was it first identified? what decreased the incidence of gonorrhea?

Answer 8

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

Question 9

describe chlamydia’s history

Answer 9

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

Question 10

what causes chlamydia?

Answer 10

chlamydia trachomatis

Question 11

what’s the most common bacterial STI?

Answer 11

chlamydia trachomatis

since the late 1990s

Question 12

what does a bacterial STI being an obligate pathogen mean?

Answer 12

the microbes have no other niche than the human body – they require human-human contact for transmission

Question 13

describe treponema pallidum, what type of bacteria is it? how is it transmitted?

Answer 13

gram-, spirochetes (more spirals than usual spirillum)

transmitted sexually or from mother to child

Question 14

why is treponema pallidum unculturable?

Answer 14

sensitive to oxygen – dies when experiencing atmospheric oxygen concentrations

does not tolerate desiccation (removal of moisture)

sensitive to high temperatures

Question 15

what are the stages of syphilis (treponema pallidium) and when do they occur?

Answer 15

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

Question 16

how many treponema pallidum cells are required to transmit the syphilis disease? what is its virulence factor?

Answer 16

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

Question 17

how is treponema diagnosed?

Answer 17

PCR

serologic tests

Question 18

what’s the treatment for treponema?

Answer 18

no vaccines are available

but there are antibiotic treatments
— penicillin or doxycycline/ceftriaxone

Question 19

describe neisseria gonorrhoeae, what type of bacteria is it? how is it transmitted?

Answer 19

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

Question 20

describe the disease of gonorrhea

Answer 20

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

Question 21

what does neisseria gonorrhea cause?

Answer 21

gonorrhea, a STD

can also cause gonococcal conjunctivitis which is a type of pink eye

Question 22

describe the cycle neisseria gonorrhoeae takes?

Answer 22

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

Question 23

what virulence factors does neisseria gonorrhoeae have?

Answer 23

type IV pili

Opa (opacity proteins)

cell wall antigen (LOS)

PorB (OM porin)

—— can prevent complement activation, opsonization, and bacterial killing

Question 24

how is neisseria gonorrhoeae diagnosed?

Answer 24

PCR

culture

Question 25

how is neisseria gonorrhoeae treated?

Answer 25

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

Question 26

describe chlamydia trachomatis, what type of bacteria is it? how is it transmitted?

Answer 26

gram- (thin or no peptidoglycan layer)

obligatory intracellular pathogen!

transmitted sexually or from mother to child

Question 27

describe the symptoms of chlamydia

Answer 27

generally asymptomatic in both women and men – explains its success

for both: inflammation, discharge

in females: infertility or ectopic pregnancy and prolonged menses

Question 28

describe the life cycle of chlamydia trachomatis (update this)

Answer 28

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

Question 29

differentiate between elementary and reticulate bodies in regards to chlamydia

Answer 29

elementary body is infectious

reticulate body allows for multiplication

Question 30

what are the virulence factors of chlamydia trachomatis?

Answer 30

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.

Question 31

how is chlamydia trachomatis diagnosed?

Answer 31

PCR

culture

Question 32

how is chlamydia trachomatis treated for?

Answer 32

no vaccine available

antibiotic treatment
— azithromycin (macrolide)
— doxycycline (tetracycline)