Acinetobacter, Franciesella, Coxiella, Legionella, and Helicobacter Flashcards
Acinetobacter species generally are generally _______ and only effect __________ patients
Acinetobacter species generally are generally opportunistsand only effect immunocompromised patients
What is the morphology of Acinetobacter sp.?
Gram (-)
rod
May pair or chain
Twitiching motility
- What do colonies of Acinetobacter sp. look like?
- How about their biochemical nature?
- May be large and mucoid or small and non-pigmented.
- Oxidase negative. Obligate aerobes.
Where are Acinetobacter spp. found in nature?
Widespread in soil, water, sewage, feces or colonizing on the skin.
List some predisposing factors that may lead to an individual to be more likely to be susceptible to a Acinetobacter infection
- Immunocompromised humans
- Patients on ventilators
- Prior use of broad-spectrum antibiotics
- Use of a urinary tract catheter
- Prior surgery
Name the important species which we talked about in class belonging to the genus Francisella?
Francisella tularensis
What Dz does Francisella tularensis cause?
Tularemia or “rabbit fever”
What are the three biovars of Francisella tularensis
Biovar tularensis
Biovar palaearctica
Biovar novicida
Where is Francisella tularensis biovar tularensis found?
Only in North America
- Where is Francisella tularensis biovar palaearctica found?
- What is the common name for this biovar?
- distributed widely and is reported primarily from Russia and the Scandinavian countries
- “Beaver strain”
What does Francisella tularensis biovar novicida cause?
Human Dz of tularemia
What is the general morphology of Francisella tularensis.
Gram negative
Short rod
Very small (0.2 X 0.7 μm)
Non-motile
Non-encapsulated
May become pleomorphic.
What nutrient does Francisella tularensis require to grow?
Cysteine
Where would one find Francisella tularensis in nature
Inside ticks, wild rodents and rabbits for biovar tularensis
Inside water rodents and beavers for biovar palaearctica
How is Francisella tularensis spread to humans?
Spread is often by contact with infected rabbits or rodents (skinning of infected rabbits is an important source) and via infected ticks.
Gains entry through skin abrasion, conjunctivae, ingestion, or aerosol.
Why is Francisella tularensis so dangerous to work with even in the laboratory?
Infectious dose is very low
Organism is one of the most highly infectious known
What does the Francisella tularensis Dz cause in rabbits?
Small, necrotic, granulomatous foci in the liver, spleen, and lymph nodes
What does the Francisella tularensis Dz cause in humans?
Site of entry to the lymph nodes and then to the liver, spleen, bone marrow, and lymphoid tissues, forming granulomatous nodules which ulcerate along the way.
(Ouch.)
What are the two forms of Francisella tularensis which you see in humans and how are they contracted?
Pneumonic form - organism is inhaled
Typhoidal form - organism is ingested
True or False
Once infected with Francisella tularensis CMI is activated, however infected individuals can relapse.
True
Infected individuals can relapse because of the intracellular organism nature of F. tularensis
A human infected with Francisella tularensis is commonly treated with what?
Streptomycin but, Gentamicin is also used effectively
To confirm a diagnosis of an animal infected with Francisella tularensis one must?
- Perform an agglutination test on patient serum
- Biopsy specimens of infected soft tissue or lymph nodes and culture
- Blood cultures can be performed if the septicemic form suspected, difficult and dangerous however
- Fluorescent antibody test used to identify the organism itself.
What is the primary species of Coxiella which we covered in class?
Coxiella burnetii
What are some common morphological features of C. burnetii?
- Small
- Pleomorphic
- Gram-negative
- Obligate intracellular organism
- Forms spore-like structures
- It exists in two antigenically distinct phases that are morphologically identical. Phase I and Phase II
What is the common Dz name for which is caused by Coxiella burnetii
Q-fever
What types of Dz does Q-fever (C. burnetii) cause in rumniants?
Abortions and respiratory tract infections
What is the the difference in Phase I vs. Phase II Coxiella burnetii?
Phase I organisms are highly infectious
Phase II organisms are less infectious and arise when cultures are passed repeatedly through eggs or tissue culture
When animals are infected with Coxiella burnetii an antibody to which phase will be made first?
Phase II
What is the primary importance of the Dz C. burnetii?
Infection of humans from contaminated animal products
List some ways to treat a C. burnetii infection?
Tetracycline
If chronic valvular endocarditis occurs then surgical correction is required
What are the signs of Acute Q-fever?
Fever
Myalgia
Headache
Sweating
What is the main complication of a chronic Q-fever?
Vegatative valvular endocarditis
True or False
To prevent Coxiella burnetii infection from occuring an inactivated Phase I product is available as a immunization for at risk populations.
True
However, before the bacterin can be used in humans, they need to be tested for prior infection. Adverse skin reactions were a problem in humans that were already infected.
What is the species name of the Legionella genus which we talked about in class?
Legionella pneumophila
What Dz does Legionella pneumophila cause?
Legionaire’s Dz
Pneumonia like Dz
(If desseminates infected patients may become delirious, confused and develop an encephalopathy)
How does one become infected with Legionella pneumophila?
Airborne droplets or water contamination
(Think small, crowded spaces like a submarine)
List the species of Helicobacter which we covered in class
Helicobacter pylori
In the lecture notes he mentions:
- Helicobacter heilmanni* (humans, cats, dogs)
- Helicobacter mustelae* (ferrets)
What is the general morphology of Helicobacter sp.
Gram-negative
Often assume U-shapes, rods, or a rounded form
Motile via a tuft of polar flagella and via a corkscrew activity in highly viscous material.
List the common Dz caused by Helicobacter pylori. (include species its found in)
Acute gastritis and gastric and duodenal ulcers in humans
What percent of humans are thought to carry Helicobacter pylori
50%
What is responsible for the majority of the tissue damage associated by a Helicobacter sp.
The urease enzyme generating ammonium ions and CO2
How does one diasnose a Helicobacter pylori infection
Histology
Culture
PCR
Stool antigen test
Serologic test
Carbon-labelled urea breath test
