Chlamydia, Rickettsia, and Intracellular Obligates Flashcards
What are three obligate intracellular pathogens?
Chlamydia, Rickettsia, and Mycobacterium leprae
What are the cell walls like of intracellular pathogens?
bacteria-like cell walls similar to gram neg bacteria
What is are the host/vectors for Chlamydia?
mammals and birds
NOT arthropods
note: rickettsia uses arthropods
What is the difference between Chlamydia and Chlamydophilia?
They are similar, but officially two different genus
Chlamydia psittacosis and Chlamydia pneumoniae are in the Chlamydophilia genus
Chlamydia Trachomatis is in the Chlamydia genus
Why is Chlamydia an obligate intracellular pathogen?
Chlamydia cannot make ATP
Depends on host ATP
There are two stages of developmental cycle…
What are Elementary Bodies?
What are Initial Bodies aka Reticulate Bodies?
EB: small, non-replicating, has cell wall; responsible for transmission from cell to cell or host to host
IB aka RB: large, replicating, no cell wall; non-infectious
What is the intracellular growth cycle?
See also page N-2 for schema.
EB causes endocytosis.
Changes to IB/RB.
Replicates and forms EB.
EB exits cell.
How many serotypes and what illnesses are caused by…
Chlamydophilia psittaci?
Chlamydophila pneumoniae?
Chlamydia trachomatis?
Chlamydophilia psittaci: one serotype causes psittacosis
Chlamydophila pneumoniae: one serotype causes pneumonia in adults
Chlamydia Trachomatis: many serotypes cause Trachoma, Lymphogranuloma Venereum, Conjunctivitis, Infant Pneumonia, Urethritis
What are the features of psittaci?
Generalized infection.
Headache and fever.
Interstitial pneumonia is most severe sign.
What is the relationship between birds and humans for Chlamydophilia psittaci?
Infection caused by inhaling bird poop, commonly by people exposed to rearing birds (parrots through turkeys)
Causes birds to have “Constant Fecal Excretion”
Why is Chlamydophilia pneumoniae important clinically?
Responsible for 10% of adult pneumonias
may play a role in coronary atherosclerosis
How is Chlamydophilia pneumoniae transmitted?
person to person via respiratory aerosols
No birds involved
What are the four major illnesses caused by Chlamydia trachomatis?
Nongonococcal Urethritis (serotypes D-K) Inclusion Conjunctivitis and Infant Pneumonia (serotypes D-K) Trachoma (serotypes A, B, C) Lymophogranuloma Venereum (serotypes L1, L2, L3)
What is the most common venereal disease?
Nongonococcal Urethritis
Are there differences between male and female Nongonococcal Urethritis infection?
How are couples Tx?
Both are commonly assymptomatic.
Symptomatic males present with purulent urethral discharge and epididumitis
Females have growth on the cervix and fallopian tubes… can result in sterility or ectopic pregnancy
Both partners must be treated regardless of symptoms
What is the relationship between Chlamydia and AIDS?
Chlamydia increases AIDS transmission
When are infants exposed to Chlamydia?
Transmitted by an infected mother, regardless of mother’s symptoms
What illnesses does Chlamydia cause in infants and children?
Inclusion Conjunctivitis
Infant pneumonia
What is Inclusion Conjunctivitis?
In whom is it seen?
How is it transmitted?
Conjunctivitis with inclusion bodies like seen with virus.
Mother to infant.
Children can infect each other at pools.
Adolescents and adults can infect each other as an STD.
What is the limitation of antibiotics to prevent or treat transmission of Chlamydia in infants or young children?
What antibiotics are usually used?
Erythromycin and Sulfonamides do no prevent inclusion conjunctivitis.
They do prevent neonatal gonococcal conjunctivitis
How is Trachoma transmitted?
By touch. Ex…
Finger to eye.
Flies to humans.
Where is Trachoma prevalent?
Tropical arid areas.
What is a sequelae of Trachoma?
Chronic reinfection causes infolding of the eyelashes and can lead to corneal scarring and blindness.
What it the Tx for Trachoma?
Azithromycin aka Zithromax aka Z pack
What are the symptoms of Lymphogranuloma Venereum (LGV)?
Two weeks: painless papule progressing to ulcerating vessicle
Four weeks: painful suppurating disease of regional lymph nodes
What is Dx of Lymphogranuloma Venerium (LGV)?
Delayed hypersensitivity skin test indicates present or prior exposure.
The test is called the FREI Test.
What are Tx for Chlamdydias?
Antibiotics that enter cells are required.
Tetracyclines or Azithromycin
All Chlamydias and Chlamydiaphilias share antigens. How are they distinguished in Dx?
For all, may use acute vs convalescent antibody titers.
Trachomatis comes from urethral or cervical smear.
Immunofluorescent, Enzyme immunoassay, DNA probe can distinguish between additional differences in antigens.
Inclusion bodies can also distinguish
Rickettsia Now
Rickettsia Now
Why are Rickettsia obligate intracellular pathogens?
No good reason. They can take up the nutrients that they need and can make their own ATP.
What is the intracellular growth cycle of Rickettsia?
Rickettsia trigger phagocytosis.
Replicate by binary fission once per day.
Export progeny.
What are the three Rickettsia species in our class?
Rickettsia prowazekii
Rickettsia typhi
Rickettsia ricketsii
Rickettsia akari
Which Rickettsia causes Primary Endemic Typhus?
Which Rickettsia causes Endemic Murine Typhus?
Which Rickettsia causes Rocky Mountain Spotted Fever?
Which Rickettsia causes Rickettsia Pox?
Rickettsia prowazekki
Rickettsia typhi
Rickettsia ricketsii
Rickettsia akari
What is the incubation period and basic symptom timeline for Rickettsia prowazekki aka Primary Endemic Typhus?
10 day incubation in capillaries
Abrupt fever and headache
4 to 7 days later: Rash
Fatal in children
What are the three types of lice that infect humans?
Head lice
Body lice
Crab lice
What is the transmission cycle between humans and lice with Rickettsia prowazekii?
What other animal can be implicated in Rickettsia prowazekii?
Body lice bite human and poop at the same time.
Human scratches bite and pushes poop into bloodstream.
Flying squirrels also carry Rickettsia
What is the Tx for Rickettsia prowazekii?
Tetracyclines
In what human circumstances is Rickettsia prowazekii aka primary endemic typhus common?
poverty, famine, and war
What is prevention of primary endemic typhus?
hygeine and lice control
What is Dx for Rickettsia prowazekii aka primary endemic typhus?
Antibody comparison between acute and convalescent
Liver function is sometimes elevated.
What is Brill-Zinsser disease?
In what demographics is this disease important?
After primary Rickettsia infection is resolved, the pathogen may be latent for decades and later cause Brill-Zinnsser disease.
Remember this if you have Russian or Eastern European patients.
What are the common hosts for Rickettsia typhi aka Endemic Murine Typhus?
Rats, squirrels, and their fleas
Where is Rickettsia typhi endemic?
USA Atlantic and Gulf of Mexico seabord
What is Dx and Tx for Ricketsia typhi?
All Rickettsia have the same Dx and Tx…
Antibody comparison between acute and convalescent
Liver function is sometimes elevated
Tetracyclines
What is the incubation period and basic symptom timeline for Rickettsia ricketsii and Rocky Mountain Spotted Fever?
1 week incubation
Fever, headache, arthritis, abdominal pain
Rash begins on hands and spreads to trunk
Lesions on palms and feet are characteristic
Mortality of 20% for untreated patients
What are the hosts of Rocky Mountain Spotted Fever?
Ticks and Humans
What is the Dx and Tx for Rickettsia Rickettsii?
All Rickettsia have the same Dx and Tx… However… See below.
Antibody comparison between acute and convalescent
Liver function is sometimes elevated
Tetracyclines
For Rocky moutain… flourescent antibody tests on skin biopsy gives immediate Dx
What is prevention for Rocky Mountain Fever?
What ticks are implicated on West coast vs East coast?
Avoid ticks.
West coast is forrest tick.
East coast is dog tick.
What are hosts for Rickettsia akaria aka Rickettsial Pox?
Mammals and mites (an arthropod) are listed. There may be more. It didn’t seem important in the notes.
What is the timeline of symptoms for Rickettsia akari aka Rickettsial Pox?
Mite bite site: primary skin lesion
1 week later: fever, chills, headache, rash that looks like chicken pox
Not life-threatening
What is the usual environmental containment of disease?
outbreaks are usually contained within a single building. Ex: apartment complex
What pathogen causes Q fever?
Coxiella burnetii
What is unique about the transmission of Coxiella burnetii aka Q fever among the obligate intracellular bacteria?
Not transmitted to humans through an arthropod bite.
However, animals themselves are infected by arthropods.
How is Coxiella burnetii transmitted?
What demographic is at risk?
Through animal placental tissue.
Animal husbanders.
What are the disease characteristics?
Interstitial pneumonia, fever, headache, high liver enzymes, sometimes a rash
What is Ehrlichioses?
a new tick-borne disease caused by two different obligate intracellular bacteria.
What is Monocytic Ehrlichiosis?
What is Granulocytic Ehrlichiois?
Mono: infects monocytes and is caused by Ehrlichia Chaffeensis
Granulo: infects granulocytes and is caused by Anaplasma phagocytophilium and is spread by deer ticks like Lyme disease
What are symptoms for Ehrlichiosis?
fever, lymphocytocpenia, elevated liver enzymes
What is Tx for Ehrlichiosis?
Tetracyclines
