Exam #6: STDs I Flashcards
What are the most common bacterial STDs in the US?
1) Chlamydia
2) Gonorrhea
What is an important distinction between bacterial & viral STDs?
Bacterial can be “cured” with medications; viral cannot–they can only be treated
What patient population traditionally have the highest & lowest incidence of STIs?
MSM= men who have sex with men have the HIGHEST
WSM= women who have sex with women–LOWEST
How does Chlamydia differ from other bacteria?
1) Lack peptidoglycan
2) Replicates within cells (obligate intracellular parasite)
*Unable to make its own ATP.
What types of infections can chlamydia cause?
Genital infections
Conjunctivitis
List the characteristics of the Chlamydiaceae family.
- Gram (-) like envelope BUT does NOT stain well
- NO peptidyglycan
- LPS with weak endotoxin activity
Describe the lifecycle of the Chlamydiaceae family
Elementary Body=”Enfectious”
Reticulate Body= Replicative form
Elementary body infects the cell & converts to the metabotically active reticulate body in roughly 12 hours. These form “inclusions” and revert to elementary bodies. Elementary bodies escape from the cell within ~72 hours.
List the characteristics of C. trachomatis.
Human is the only known host
Two biovars: Trachoma & LGV
Multiple serovars
What infections does C. trachomatis cause?
Eye infections
Urogenital infections
What are the two C. trachomatis biovars? What is the difference between the two?
LGV= more invasive Trachoma= less invasive
What are the different C. trachomatis serovars? What are serovars?
Different Major Outer Membrane Protein (MOMPs), lead to different immune responses that can be detected by serologic analysis.
Trachoma= A, B, Ba, C D-K= Urogenital tract disease LGV= L1, L2, L2a, L2b, & L3
What does C. trachomatis have a trophism for?
Nonciliated, columnar, cuboidal, & transitional epithelial cells of the:
- Urethra
- Endocervix
- Endometrium
- Fallopian tubes
- Anorectum
- Respiratory Tract
- Conjunctivae
How does C. trachomatis cause infection (pathophysiolgy)?
- Reticulate bodies cause destruction of the cell & cause:
- Pro-inflammatory reactions that when prolonged, leads to fibrosis & potentially infertility
What is trachoma?
A chronic inflammatory granulomatous process of the eye, leading to corneal ulceration, scarring, pannus formation, & blindness
“Leading cause of preventable blindness in the world” caused by C. trachomatis infection
What is adult inclusion conjunctivitis? What is neonatal conjunctivitis?
“Acute conjunctivitis in sexually active adults”
What are the symptoms of adult inclusion conjunctivitis?
Mucopurulent discharge
Dermatitis
Corneal infiltrates
Corneal vascularization in chronic disease
What are the symptoms of Chlamydia, or C. trachomatis urogenital infections?
Men
- Dysuria
- Thin mucopurulent discharge
Women
- Mostly ASYMPTOMATIC (80%, which has important implications for disease spread)
- PID
What complications can be seen from C. trachomatis urogenital infection in men?
Epididymitis
Prostatitis
Reiter Syndrome
What is Reiter Syndrome?
1) Uretheritis
2) Conjuncitivitis
3) Polyarthritis
4) Mucocutaneous lesions
What are the symptoms if PID?
Pelvic inflammatory disease
- Inflammation of the uterus, fallopian tubes, & other reproductive organs
- Abdominal pain, adnexal tenderness, & cervical motion tenderness (CMT)
- Can cause scarring & sterility, or ectopic pregnancy
What patient population is at risk for LGV?
Sexually active individuals that travel to Africa, Asia, & South America
What are the symptoms of LGV?
- Small, painless ulcers on genitals that become swollen
- Painful inguinal lymph nodes that ulcerate
How is C. trachomatis diagnosed?
Need a SCRAPING of the location
- Giemsa stain with cytoplasmic inclusions
- Iodine that stains reticulate bodies
- Immunoflouresecence (ELISA) of EBs
NAAT or PCR is the most common diagnostic test
How is C. trachomatis prevented?
1) Safe sex, early detection, & treatment of symptomatic pateints
2) Control of re-infection; infection does NOT confer immunity
How is C. trachomatis treated?
Doxycycline
Macrolide (Azithromycin)
50S ribosome inhibitors–> disrupt protein synthesis
What is the mechanism of action of Doxycycline & the Macrolides?
Inhibition of protein synthesis (via inhibtion of the 50S subunit)
List the characteristics of Neisseria gonorrhoeae.
Gram (-) diplococci
Maltose (-)
vs. Meningitidis that is Maltose (+)
What virulence factors are associated surface of N. gonorrhoeae?
Pilin= attachment & anti-phagocytic
Por protein= promotes intracellular survival
Opa protein= attachment to eukaryotic cells
LOS= Lipid A & core oligosaccharide without O-antigen–>endotoxin
*all undergo antigenic variation to avoid immune response
IgA protease
B-lactamase
How does N. gonorrhoeae antigenically vary?
Neisseria LOS, Pilin, porin, & Opa protein can be antigenically altered; thus, the immune response is generated does not prevent reinfection
Describe the pathophysiology of N. gonorrhoeae?
- Gonococci attach to mucosal cells (Pili, PorB, Opa mediated)
- Penetrate into cells & multiply (primary site is cervix in women)
- LOS stimulates inflammation; TNFa & chemokines are responsible for symptoms
Who is most at risk for N. gonorrhoeae infection?
Africa American 15-24 year-olds Southeastern US Multiple sex partners Late complement (MAC C5-C9) mutations
What are the symptoms of N. gonorrhoeae infection?
Mucopurulent discharge
Dysuria
*Most men have symptomatic infection; 1/2 of women
What are the complications of N. gonorrhoeae infection?
Men:
- epididymidis
- prostatitis
- periuretheral abscess
Women:
- salpingitis
- tubovarian abscess
- PID
How does disseminated N. gonorrhoeae present?
Septicemia Skin infection Joint infection Suppurative arthritis Pustular rash
*Note that disseminated N. gonorrhoeae is the leading cause of purulent arthritis in adults
What is purulent conjunctivitis?
Purulent ocular infection in newborns infected during vaginal delivery
Note that this is also called “Opthalmia Neonatorum”
How is N. gonorrhoeae diagnosed?
1) Direct smear= Gram (-), bean-shaped diplococcus in neutrophils
2) Culture & growth of uretheral (men) or cervical (women) scrapings
3) NAAT
What type of agar needs to be used for culture of N. gonorrhoeae?
Chocolate
How is N. gonorrhoeae treated?
Ceftriaxone (N. gonorrheae)
Doxycycline or azithromycin*
*To treat chlamydia (prophylactically)
How is opthalmia neonatrorum prevented & treated?
- Prophylaxis with erythomycin ointment
- Ceftriaxone for opthalmia neonatorum
