Woychik - Mycoplasma, Spirochetes, Chlamydia, Lyme, Ricketssia, And Others Flashcards
Why are mycoplasma difficult/impossible to gram stain?
They do not have a cell wall. Rather, they have a 3 layered cell membrane.
- therefore they are resistant to penicillin.
Mycoplasmas morphology
Have unusual colonies on agar plates.
- M. Pnemonia - has mulberry shaped colonies but can also be spherical
- the other three types of mycoplasmas generally have a fried egg appearance.
Nutritional requirements for growth of mycoplasmas
They require cholesterol or a cholesterol source because they need it for their cell membranes. So, this is added to their medium.
- very slow growing bacteria.
How is mycoplasma pneumonia transmitted?
It is transmitted from person to person through respiratory secretions.
What populations are more likely to get pneumonia??
Populations in closed quarters such as military or college
How does Mycoplasma pneumonia cause respiratory pathogenicity?
It has a high affinity for respiratory epithelial cells. It attaches at the base of the cilia, which causes loss of ciliary action, followed by loss of cilia, then sloughing of the cell into the lumen, which produces the cough.
How long is the incubation period of mycoplasma pneumonia?
2-3 weeks
Typical symptoms of mycoplasma pneumonia
Gradual onset of fever, malaise, headache, and cough.
How does the age of the patient affect what kind of symptoms they present with?
3 or less - upper respiratory
5-20 - bronchitis and pneumonia
Older - pneumonia
Laboratory diagnosis for mycoplasma pneumonia
Cold agglutination - obsolete
PCR - most specific and rapid
- usually just go undiagnosed so they treat with standard drugs for community acquired pneumonia, which won’t work because they are usually beta-lactams
What does mycoplasma pneumonia cause?
Walking (atypical) pneumonia
What are the spirochetes?
BLT
- borrelia Burgdorferi and borrelia recurrentis
- leptospira Interrogans
- treponema Pallidum
What is the name of the tick that caries Lyme disease???
Ixodes
What animals are reservoir for Lyme disease?
White footed mouse and deer
Why are confections common with Lyme disease?
Ixodes tic is a vector for other pathogens as well.
For how many hours does the tic need to be attached to get Lyme disease?
24 hours
What is the prophylactic treatment for Lyme disease?
Doxycycline
What did the Lyme disease vaccine target?
The surface lipoproteins, OspA-F, which are the virulence factors.
OspA-F
Virulence factors for Lyme disease that cause attachment to mammalian cells.
Stage 1 Of Lyme Disease
- Erythema migrans
- feverish symptoms
Stage 2 of Lyme Disease
Days to weeks after tick bite - flue like symptoms
Weeks to months after tick bite - musculoskeletal pain in joints and bones, cardiac disease, and Bell’s palsy.
Stage 3 of Lyme Disease
Months to years after tick bite - chronic nervous system and joint involvement. Causes Lyme arthritis in large joints such as the knee.
Laboratory diagnosis of Lyme Disease
Usually you just treat if you see the erythema migrans. If it isn’t there, you do a two tiered approach of ELISA and then Westerb Blot.
When doing a Wester Blot, how many lanes have to be positive to make a diagnosis of Lyme Disease?
IgG - 5 out of 10
IgM - 2 out of 3
What is the name of the disease caused by borrelia recurrentis?
Relapsing fever
How does one get endemic relapsing fever?
Tick bite - but not same tick as Lyme disease.
- reservoir is small animals and rodents
What area of the country is relapsing fever most common?
Western US
In what area of the US is Lyme disease most common?
Northeastern US
Clinical Characteristics of Relapsing Fever (Borellia recurrentis)
Fever, malaise, for 3-6 days. Then relapse every 7-10 days until you clear the infection.
- Basically what is happening is that a different set of antigens are put out and then the body clears it. But eventually no more antigens can be put out and the infection can be cleared permanently.
What disease is associated with leptospira Interrogans?
Leptospirosis
How does one get leptospirosis?
Usually from ingestion of contaminated water or food, swimming or bathing in contaminated water.
- What can happen is that a wild animal like a raccoon can urinate, the dog might drink it, and then you might come into contact with the dogs urine or saliva.
In what area is leptospirosis most common?
Hawaii
Symptoms of leptospirosis
Flu like symptoms at first
- Later on the disease affects the whole body including the kidneys and liver.
What disease is associated with treponema Pallidum?
Syphillis
How is Treponema/Syphillis transmitted?
Most often through sex
- can also be through placenta during birth, kissing, transfusion, other sexual contact.
Stages of Syphillis.
Primary: usually see a lesion occurring at inoculation site.
Secondary: “disseminated stage” where there are lesions in many places on the body.
Latent/Late/Gummatous: slow progressing inflammatory disease affecting any organ in the body.
- could cause neurosyphillis and cardiovascular Syphillis.
- in the Gummatous stage there is sometimes lesions in the skin and bone.
Congenital Syphillis
If the mother has Syphillis, it could result in fetal death/miscarriage. Looks like congenital abnormalities:
- notched teeth
- saber shins
- saddle nose
What group of people are particularly at risk for Syphillis?
Homosexual men
Laboratory diagnosis of Syphillis
Dark-field microscopy - take some exudate from a primary, secondary, and congenital lesions
Measure either nonspecific nontreponemal or antitreponemal antibodies.
Nontreponemal tests
They use cardiolipin as the antigen. Then they add lecithin and cholesterol to sensitize the cardiolipin. Then they add the patients serum, which has reagin in it from the Syphillis and you see hemagluttination.
There are two types of nontreponemal tests that test for the presence of reagin. What are they?
1) Flocculation tests - VDRL, RPR
2) Complement-fixation - reagin in the serum can fix complement in the presence of cardiolipin.
What are some advantages and disadvantages of nontreponemal tests for Syphillis?
A: cheap, easy
D: reagin are in other diseases other than Syphillis.
Specific treponema like tests
They detect Treponema Pallidum antibodies in the patients serum, which remain for life.
Names of specific treponemal Ab tests
FTA-ABS - uses indirect immuno fluorescence
TPHA - RBCs treated to absorb T. Pallidum on surface and then they clump with antitreponemal Abs.
How is the Ricketssia organisms spread?
Fleas, lice, mites, ticks and other arthropod vectors.
How is coxiella burnetii spread?
Sheep, goats, and cattle.
COmmon symptoms of Rickettsia and Orientia
Fever, headac, rash
What species of the rickettsia group is in the Spotted Fever Group?
Rickettsia rickettsii, which causes Rocky Mountain Spotted Fever
Rickettsia akari, which cause Rickettsialpox
When does the hallmark rash of Rocky Mountain spotted fever take place?
2-4 days after onset of illness.
What are the virulence factors of Rickettsia rickettsii?
OmpA and OmpB, which aid in the attachment to host vascular endothelial cells outer membrane. They then induce phagocytosis. Once they are in the phagosome, they escape into the host cytosol and proliferate. This causes cell damage leading to increased vascular permeability. Then they spread to adjacent cells though host cell actin-mediated propulsion. This causes the classic petechial rash.
What is a diagnostic feature of Rocky Mountain spotted fever? Wait is another disease that could cause this
Petechial rash on the hands and feet.
- Syphillis could also cause rash on the hands and feet.
What disease is associated with Rickettsia akari?
Rickettsialpox
What are the clinical characteristics of Rickettsialpox?
At the site of the mouse mite bite there will be a primary papule that forms, ulcerated, and forms a dark Eschar. As infection progresses, a fever comes about with an accompanying 20-40 eschars.
Which strains of rickettsia/Orientia are members of the typhus group?
Rickettsia prowazekii
Rickettsia typhi
Orientia tsutsugamushi
What causes rickettsia prowazekii outbreaks?
Usually parallels times of war, natural disaster, lack of changing clothing, infrequent washing.
What disease is associated with Rickettsia prowazekii?
Louse-borne typhus
What is the vector for rickettsia prowazekii?
Body louse
What animal in the US have been shown to be a good reservoir for Rickettsia prowazekii?
Flying squirrel
What disease is associated with Ehrlichia chaffeensis?
Human Monocytic Ehrlichiosis
What are the distinguishing features of Human Monocytic Ehrlichiosis?
Leukopenia and thombocytopenia
What disease is associated with Anaplasma phagocytophilum?
Human Granulocytic Anaplasmosis (HGA)
What disease is associated with Coxiella burnetti
Q Fever
What is the most common reservoir for coxiella burnetti?
Sheep, goats, cattle
- they shed the organism in the urine, feces, milk, and placenta.
WHat are the symptoms of Rickettsia prowazekii
Arthralgias, myalgias, pneumonia, rash that spares the hands, feet, and head.
Transmission of Coxiella burnetti
It becomes aerosolized and breathed in.
Symptoms of Q fever
Fever, headache, pneumonia, hepatitis
- NO RASH
