Exam 2 Lecture 19 Flashcards
Describe the Gram Stain of Spirochetes
Gram negative, cork-screwed bacteria
Name 2 families in the spirochetes that are free living and non-pathogenic
Spirochaeta, Cristispira
Name the spirochete family responsible for causing syphilis and periodontal disease
Treponema
Where do Spirochaeta live?
Hot springs, marshes
Where do Cristispira live?
Inside mollusks
Name the spirochete family responsible for causing relapsing fever
Borrelia
Name the spirochete family responsible for causing Lyme disease
Borreliella
Name the spirochete family that is free-living but CAN be pathogenic
Leptospira
Name the spirochete family responsible for causing dysentery (bloody diarrhea) in pigs, chicken, and sometimes humans
Brachyspira
Which spirochete has hooked ends?
Leptospira
What is special about the flagella of spirochetes?
It’s under the outer membrane inside the periplasmic space
Of the spirochetes we learned about, which one has the largest genome size?
Leptospira (L. interrogans)
Although most bacteria have a circular chromosome structure, ……. and ….. have linear chromosomes.
B. hermsii, B. burgdorferi
How many circular chromosomes does Leptospira have?
2
While B. hermsii and B. burgdorferi have a linear and circular plasmid, no plasmid has been detected in ….. and …..
Leptospirosis (L interrogans), T. pallidum
True or False: The spirochetes we learned about all have high genetic variability
FALSE - T. pallidum has very low genetic variability
The molecular % of G and C content is highest in which spirochete?
T. pallidum
Which spirochete is difficult to grow in vitro culture?
T. pallidum
Two species of spirochetes can cause relapsing fever, what are they?
B. hermsii (tick-borne) and B. recurrentis (louse-borne)
True or False: B. hermsii is tick-borne
True
Describe the transmission of B. hermsii in ticks
It invades the tissue of ticks and infects their ovaries, so the offspring are also infected w/ B. hermsii
Lab studies have determined that over __ generations of ticks are born with B. hermsii due to transovarial transmission.
9
True or False: In contrast to B. burgdorferi, which requires a long feeding time for infection to occur, B. hermsii requires a short feeding time
True
What is the reservoir for ticks that can cause relapsing fever?
Squirrels, other rodents
What is the reservoir for lice that can cause relapsing fever?
Humans (no known animal reservoir)
True or False: Louse-borne infections by. B. recurrentis can be spread from human to human.
True
True or False: B. recurrentis does not invade louse tissue
True
What is the incubation time for relapsing fever?
7 days
Name the symptoms of relapsing fever (3)
- fever
- headache
- pain (muscles, joints, bones)
Spikes of fever in relapsing fever is associated with ….
High concentration of spirochetes in the blood (10^7 - 10^8 bacteria/mL)
What is the cause behind recurrent fevers?
A new serovar overgrows when the first one is overcome by the immune system
Antibodies are made against ____ ______ _____.
variable membrane proteins
New variants of B. recurrentis or B. hermsii appear in the population at a frequency of …..-…… cell per generation
10^-3 to 10^-4
True or False: New variants have a selective advantage as antibodies appear to earlier variants
True
Variation of variable membrane proteins (VMPs) is a classic example of _____ _______.
antigenic variation
VMPs are placed into 2 categories. What are they?
VSPs and VLPs
variable short proteins) and (variable long proteins
VLP and VSP genes are found on a ______ plasmid in a ____ state, where sequences can be recombined into an ______ site on another plasmid.
linear
silent
expression
True or False: Borrelia are normally not invasive to humans and can be cleared out within weeks
FALSE: borrelia are very invasive to humans and can infect tissues, organ systems (including CNS)
A particular ___ allele has been associated with CNS localization.
vsp
How is relapsing fever diagnosed?
Clinical features, PCR, blood films taken during fever
What is the antibiotic treatment for relapsing fever?
Penicillin & Tetracyclines
__ ________ is the main pathogen that causes Lyme Disease in the United States
B. burgdorferi
What is the main reservoir for B. burgdorferi?
Mice, birds, deer
True or False: Infection by B. burgdorferi from a tick bite is usually accidental
True
Ixodes scapularis is the main vector of Lyme Disease in North Americans, which developmental form of it the one that bites and infects animals/humans?
Nymph
True or False: The % of ticks infected with B. burgdorferi is constant throughout the US
False - NY, Minnesota, and Wisconsin have more infected ticks
Typically, a nymphal tick needs to be feeding on a mammal for at least __ hours for Lyme disease to occur
24
What is special about tick saliva that allows it to feed for a long period of time?
It contains factors that stop the host’s blood from clotting
In order for a tick to infect its host, it needs to have _____. ____ is not enough for infection to occur.
OspC
OspA
What is the first stage of Lyme disease?
ECM (target like lesion forms)
What is the second stage of Lyme disease?
Neurologic and cardiac abnormalities; headache, stiff neck, conjunctivitis, myalgia
What is the third stage of Lyme disease?
Arthritis
How is Lyme disease diagnosed?
Evidence of ECM, biopsy, PCR
True or False: Serologic tests are unreliable and can lead to misdiagnosis of Lyme disease
True
What antibiotics are used to treat Lyme disease?
Tetracyclines, Penicillin, Ceftriaxone
True or False: B. burgdorferi has been found in tissue despite antibiotic treatment
True
Name the organism responsible for syphilis
T. pallidum
True or False: Syphilis needs high amounts of O2 for survival
False, it’s a microaerophilic
T. pallidum relies heavily on host cells for its own ______. It does not synthesize nucleotides, amino acids, or fatty acids. It also does not do ___ or ____ cycle.
metabolism
ETC
Kreb’s cycle
True or False: Similar to with relapsing fever and Lyme disease, Syphilis can disseminate and pass the blood brain barrier
True
Name the characteristics of primary Syphilis infection
genital ulcer, regional lymphadenopathy
Name the characteristics of secondary Syphilis infection
rash all over the body (including palms)
Name the characteristics of tertiary Syphilis infection
gumma, CV syphilis, paralysis, blindness
True or False: Syphilis can cross the placenta to cause congenital syphilis
True
Name the possible consequences of congenital syphilis
premature baby, spontaneous abortion, stillbirth, illness, latent infection
When syphilis is untreated, the primary and secondary lesions are eventually ____, however infection remains ______
cleared
systemically
Some outer membranes for Syphilis bind ……, ……., …….
fibronectin
laminin
fibrinogen
What is TprK?
A surface-exposed protein expressed by T. pallidum
TprK has __ variable regions, but over ___ donor sites
7, 50
How is syphilis diagnosed?
Serologic testing, darkfield microscopy
- *PCR is not available commercial
- *No culture available
What is the first line antibiotic treatment for syphilis?
Penicillin
Name 2 alternative antibiotics used for treating syphilis
Doxycycline, tetracyclines
Syphilis strains have higher levels of resistance against ______
Macrolides
L. interrogans, which causes Leptospirosis, has ____ serovars
300
In contrast to other spirochetes discussed, L. interrogans is ________
free-living
Where is L. interrogans found?
in water
What is the reservoir of L. interrogans?
Wild/domestic animals (raccoons, opossums, skunks)
What is the source of L. interrogans in water?
It is contaminated by infected urine of animals like mice
What age groups are most at risk for Leptospirosis?
Teens, young adults
The bacterial load can reach up to ____/gram of tissue in the kidneys
10^10
Although most individuals who get Leptospirosis are asymptomatic or have non severe symptoms, some people can get diseases such as:
renal failure
jaundice
aseptic meningitis
pulmonary hemorrhage
What is the incubation period of Leptospirosis?
7-10 days
Leptospirosis is particularly dangerous when in the _____ form
icteric
How is Leptospirosis diagnosed?
- PCR
- Culture
- Serology (ONLY IN LATER INFECTION)
Blood, and CSF samples are used in ___ stages of leptospirosis, while _____ samples are used in _____ leptospirosis
early
urine
late
Name the antibiotic treatment used for Leptospirosis
Penicillin, doxycycline, erythromycin
