Spirochetes Flashcards
What does Treponema pallidum gram stain and shape?
-Gram−spirochete
Does Treponema pallidum have LPS?
No
- Gram−spirochete but no LPS
- flagella (3/pole) in an axial filament (between inner &outer membrane)
- fragile (only survive transmission without exposure):sexual and congenital (placental)transmission in body fluids and mucous membranes
Treponema pallidum
What is the main virulence factor of Treponema pallidum?
host response causes disease symptoms
Which sexually tansmitted diease was passed from native american people to settlers? (a new world —> old world disease)
Syphilis
• sexual (human reservoir)
• congenital (spirochete
crosses placenta: late lethality
Transmission of Syphilis
1. local: hard chancre/ulcer at site of infection; infectious 2. disseminated: rash, aches; mucous membrane lesions (“the great imitator”); infectious 3. gummas; damage to blood vessels, eyes, CNS; insanity; not infectious
Stages of Transmission of Syphilis
2-6 weeks; chancre, which heals
spontaneously, giving false sense of relief.
Primary Syphilis
2-24 weeks
Asymptomatic period:
2-6 weeks; 50% of primary
infections go on to secondary; symptoms typically
resolve spontaneously (but recurrence in 25% with 1 yr)
Secondary syphilis
Microbe persists for 2/3 of secondary infections, with 1/2 exhibiting tertiary syphilis
diffuse, chronic inflammation
Tertiary syphillis
These form in tertiary syphilis
granuloma lesion = inflammatory mass which can perforate, e.g. roof of mouth or any other tissues.
gummas
T/f: congenital syphilis is completely preventable by penicillin treatment early in pregnancy!
true
_______ has high lethality in-utero OR when initially born without symptoms: high lethality typical of young children (e.g. 2 yrs old) with facial and dental abnormalities like “Hutchinson’s incisors” and “mulberry molars”.
Syphilis
______ for 1º and 2º syphillis infections, which contain actively growing spirochetes
penicillin
T/F: there is no vaccine for syphillis
true
t/f: borrelia is a gram negative spirochete
true
Lyme disease is caused by _____ ______.
Borrelia burgdorferi
______ ______ ______ life cycle can be traced showing the tranmission of Borrelia burgdorferi.
Ixodes scapularis tick
The tick transmission cycle sustains the bacteria _. _______, that cause lyme disease. Lyme disease risk is greatest in the spring and summer, but can occur during all four seasons. nymphs, which feed in the later spring and the early summer, are responsible for tranmitting the majority of infections to humans.
b. Burgdoferi
_______ _____ is tranmitted through ticks and reservoir (deer/ rodents)
Lyme Disease: Borrelia burgdorferi
Disease:
1. acute, local: fever
- disseminated: nerve
paralysis (with heart
arrhythmia)(2-8 wks) - chronic: arthritis,
CNS paralysis (due
to persistent immune
response)(>6 months)
Lyme Disease: Borrelia burgdorferi
What skin symptom is characteristic of lyme disease?
erythema migrans rash
Is there an effectice vaccine for lyme disease?
no
Virulence Factor:
Relapsing fever due to effective immune response to antigenic variation
Relapsing Fever: Borrelia spp.
Infection: Relasping fever epidemic (louse-bourne)
Reservoir: human
Vector:
body louse
b. recurrentis
Infection:
relasping fever endemic
Reservoir:
rodents, soft shelled ticks
Vector:
soft shelled ticks
b. miyamotoi
Gram -
obligate intracellular parasite
entry into endothelial cells, escape
vascular hemorrhages
(no laboratory culture)
Transmission of this zoonosis: • wood tick (including transovarian transmission from adult ticks into tick eggs) • reservoir: wild rodents
Rickettsia
Disease:
• rash of extremities, then trunk
• hemorrhagic lesions (with disseminated vascular CTL lysis of endothelial cells) ► spots
• dissemination to heart, kidneys, etc ► shock, death No vaccination (mortality = 20-40% if no treatment)
Rocky Mountain spotted fever
Agent of chlamydia
Chlamydia trachomatis
The most frequent sexually transmitted infection (followed by
gonorrhea, AIDS and syphilis)
Chlamydia
Obligate intracellular parasite (no laboratory culture; “AT P ”-parasite)
Chlamydia
No “peptidoglycan” synthesis (although the bacterial cell wall looks ‘normal G−’
Inflammatory cytokines released from infected cells cause disease manifestations: damaging cell-mediated immune response in various
tissues.
Chlamydia trachomatis
EB: epithelial cell adhesion to microvilli ► RB in phagosomes (no fusion with
lysosomes) ► replication and division ► EB ► cell lysis / exocytosis
Tranmission of Chlamydia trachomatis
EB = elementary body
stable, infectious
Chlamydia trachomatis
RB = reticulate body
(replicating, fragile,
non-infectious)
Chlamydia trachomatis
8 serotypes: gonorrheal-like sexual disease
• Mucopurulent urethritis, cervicitis, salpingitis (fallopian tube
infection)
• mobility by adhesion to sperm (► epididymitis prostatitis in men) • PID (pelvic inflammatory disease) ► scarring ► ectopic pregnancy
+ decreased fertility
3 serotypes: lymphogranuloma venereum
4 serotypes: trachoma (endemic chronic eye infection: blindness)
ophthalmia neonatorum with conjunctivitis and pneumonia
Chlamydial diseases caused by CMI responses
- no immune protection
-reinfection: stronger CMI
C.pneumoniae strain causes “walking pneumonia”
Chlamydial diseases caused by CMI responses
non-Gram staining (no rigid cell wall: no effect of
penicillin or lysozyme); strong membrane (due to sterols) no sterilization by filtration (0.45μm) Mycoplasma species are smallest prokaryote (M.
genitalium 580,070 bp – 475 genes) strict aerobe (preference for bronchial mucosa)
Disease:
no vaccination; fading protective immunity after recovery
• atypical, mild pneumonia, the leading cause in schools, students, and military: aerosol transmission in crowded conditions
Mycoplasma pneumoniae
capsular vaccine is available
pneumococcal pneumonia
no vaccine available
klbsiella pneumonia
mycoplasmal pneumonia
t/f: Mycoplasma pneumonia is also known as “walking pneumonia” because it is typically mild and without the
need for hospitalization.
true
