Chlamydia - Bailey Flashcards
Chalmydiae is gram ______ & has ______ outer membrane.
- Negative
- LPS
True or false, Chlamydiae has no peptidoglycan in the cell walls?
True!
What is the size of Chlamydiae?
Small (.25um - .8um)
______ is the leading cause of preventable blindness in the world & the most common agent of sexually transmitted bacterial infections.
Chlamydial infections
How do Chlamydial infections occur? Exposure? Infection? Spread?
Exposure = Droplet or direct contact. Infection = mucosal epithelial cells *Localized usually eyes, lungs & genitalia Spread by the 4 F's: Fingers Flies Fomites Fornication
Chlamydial are “energy parasites” this means they depend on the host for _____.
ATP
Chlamydiae is classified as a _______.
Obligate intracellular pathogen
*Grows only inside or on live tissues (Human, animals, insects..)
What are the 4 species of Chlamydia?
- C. trachomatis
- C. pneumoniae
- C. psittaci
- C. pecorum
* 1 & 2 are primarily human pathogens
* 3 & 4 are primarily animal pathogens but can cause disease in humans
Tell me about C. Trachomatis infections in men and women…
Genital tract infections
Men = prosititis , epididymitis
Women = Cervicitis, PID, premature births, pelvic pain & newborn eye and lung infection.
Both = Urethritis, infertility, proctitis and arthritis.
*Usually asymptomatic in females.
True or false?
C. trachomatis infections are always chronic?
False! They can be acute or chronic.
*During birth infants can contract an infection leading to conductivity and pneumonia if the mother has C. Trachomatis.
Describe how C. Trachomatis enters the cell….
- While still outside the cell it exists in Elementary body transit form (EB)
- The EB’s masquerade as nutrients, growth factor, hormones to bind to specific receptors
- EB’s are then internalized by receptor-mediated endocytosis.
How do EB’s modify the endocytic vesicle?
2 ways!
- maintain pH above 6.2 preventing vesicle from fusion with lysosomes
- Vesicle is also modified with host components (glycolipids) for camouflage.
After infiltration of the cell, infectious EB’s change into what?
Larger intracellular active organisms called (RB’s)
What do RB’s do?
Synthesize molecules using host metabolites and energy
*Divide by binary fission.
How quickly do RB’s develop?
Slowly
2-3 days per cycle
How do RB’s uptake nutrients?
They have tubelike structures that act as straws and allow them to feed on the eukaryotic host cell without leaving the inclusive vacuole. *18-23 hollow tubes per RB.
What is Trachoma?
Ideas caused by strain of C. trachomitis.
- Inflammation of the conductive can cause blindness, scarring of cornea.
- spread by direct contact with eye, nose and throat secretions from affected individuals or indirect contact (Washcloth) .
What is Lymphogranuloma Venerum?
an STD.
-Systemic, invasive infection apparent in the lymph nodes that drain the genital tract. (Not as common is US)
What is quite possibly the most prevalent chlamydial pathogen in the human population?
Chlamydophila pneumoniae
- 50% of people up to age 20 have been infected, 80% of older people have.
_________ can be directly observed in 40-100% of patients with atherosclerotic heart lesions.
Chlamydophlia pneumoniae
What is the treatment for Chlamydia?
Antibiotics must be maintained for a long time because the organisms grow slow.
There are 4 membranes that must be penetrated:
- host cell plasma membrane
- Inclusion membrane
- Chlamydial outer membrane
- Chlamydial cytoplasmic membrane
*Antimicrobial target active RB’s
What are the characteristics of Rickettsiae? (3 things)
- small gram negative rods
- Obligate intracellular bacteria
- *Zoonoses = infections transmitted from animals to humans.
Describe how Rickettsiae obtains “energy”…
- NOT a energy parasite like Chlamydiae
* Can synthesize some of their own ATP and are capable of independent metabolism.
How is Rickettsiae transmitted?
Ticks! aka (Bloodstream)
- Larva ticks feed on rodents and then on large mammals as adults (Where they can become infected with R. Rickettsii)
- They can then infect a human if they bite them.
- Once a tick is infected it is infected for life.
How does Rickettsaie spread and multiply in the bloodstream?
- Attaches to small blood vessels and induces endocytosis
- once inside, they lyse the phagosome and enter the cytosol.
What is the mode of exit for Rickettsaie?
Mode of exit varies…
- R. Prowazekii exists by cell lysis
- R. rickettsia get extruded from the cell through local projections (Filopodia) *actin in the host cell helps push the bacteria through this projection)
- R. tsutsugamushi exits bu budding through the cell membrane (remains enveloped in host cell membrane as it infects other cells.
What does Rickettsiae do to the host?
Lysis of the cells result in leakage of blood which causes a rash (Hemorrhagic spots)
- Organisms can travel to other vessels including brain and heart.
- 75% of patients will clear the infection even before antimicrobial treatment.
What are the 3 Typhus group fevers?
- R. Prowazekii
- R. Typhi
- Orientia tsutsugamushi (scrub typhus)
What causes typhus fever?
R. Prowazekii (Transmitted by human lice) *Reservoir is humans and flying squirrels
What causes murine typhus?
R. Typhi
*transmitted by rats and rat fleas.
What is unique about Scrub typhus?
NO RASH! unlike the others.
- caused by Orientia tsutsugamushi
What is Ehrlichia? Transmission? Infection? Symptoms?
- Its an obligate intracellular bacteria
- Transmitted by Lone Star Tick (This is the Walker Texas Ranger of ticks)
- Infects mostly monocytes and macrophages.
- symptoms include: fever, malaise, headache and myalgia.
- Develops in host cell vacuoles first last reticulate cells and then as dense core cells.
How is Rickettsioses diagnosed? (4 ways)
- antibody filters
- fluorescent antibody assay
- Complement fixation
- Latex agglutination
4 Fun facts about Mycoplasma! GO!
- Smallest organisms capable of growth on cell free media.
- Lack a cell wall (Not sensitive to penicillin!)
- Cell membranes contain sterols
- Found in other mammals and birds.
What are the 4 species of Mycoplasma?
- M. pneumoniae (Primary atypical pneumonia)
- M.genitalium, M. hominis & Ureaplasma urealyticum (These last 3 cause Genitourinary tract infections)
- Some mycoplasmas are part of the normal human flora.
What are the reservoirs of M. Pneumoniae?
Humans only!
What is “walking pneumonia”?
Primary atypical pneumonia, not cleared by penicillin.
How is M.Pneumonia transmitted and where does it infect?
- Transmitted by respiratory droplets.
- Adhere to respiratory epithelium.
The main cells of the inflammatory response associated with M. Pneumonia are ________.
Lymphocytes
True or false, M.Pneumonia is highly destructive to tissues….(body tissues not kleenex)
False! However it does impair ciliary function.
What “other” damage can M.pneumonia do?
- Hemolytic anemia = detectable in 50% of cases.
- Encephalitis
- Erythema multiforme (rash)
_______ is the newest emerging human pathogen.
M. Genitalium (a lot like M. Pneumoniae)
______ & _______ are frequently associated with diseases in newborns (commonly found in the respiratory tract and genitourinary tracts)
M. Hominis & U. Urealyticum
* can be isolated from the spinal fluid of newborns, yet don’t always cause disease.
