Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
31 Cards in this Set
- Front
- Back
|
What do you call a bacteria without a cell wall?
With no cell wall, what kind of shape are they? |
Mollicutes...or mycoplasma
They are sort of like slugs. They are pleiomorphic |
|
|
What are the three major genera of mycoplasma? In which group are most of the pathogens?
Are they host-specific? |
Mycoplasma, Ureaplasma,
Acholeplasma- most pathogens are in Mycoplasma • Very diverse group- many hosts, many diseases. |
|
|
Of the free-living bacteria, which have the smallest genomes?
Where do these guys inhabit? |
Mollicutes
Smallest genomes of all living organisms- thus fastidious growth requirements. Requires complex medium- sterols, nucleotide source, ADP, particular pH range • Found on all mucosal surfaces - can go systemic. |
|
|
What are the smallest prokaryotic cells?
Why does this make many scientists hate them? |
Mollicutes
mollicutes are infamous for contaminating _cell cultures_. |
|
|
Can you treat mycoplasma with penicillin?
|
No, you can't treat them with anything that targets the cell wall, because they don't have one.
No _peptidoglycan_, no outer membrane, no LPS- most closely related to Gram pos. (Clostridia and Bacillus) |
|
|
Do mollicutes have peptidoglycan? What does this mean?
Do they have LPS? |
no
antibiotics targeting cell walls don't work (like penicillin) LPS- most closely related to Gram pos. (Clostridia and Bacillus) |
|
|
What gram stain are mollicutes? They are obligate what? Facultative what?
|
LPS- most closely related to Gram pos.
(Clostridia and Bacillus) Obligate parasites- do not live in any environment not associated with a host Facultative anaerobes, like higher CO2 |
|
|
Which mollicute produces urease?
Which are sensitive to digitonin? |
• Digitonin targets membranes that have cholesterol
• Disk sensitivity assay- like Kirby-Bauer • Mycoplasma/Ureaplasma sensitive to Dig. • Other Mollicutes are not. Sensitivity to digitonin Urease production • Ureaplasma yes, others, no. |
|
|
What are the mycoplasma virulence factors?
|
• _Ciliastasis_- intimate contact by mycoplasma with ciliated epithelial cells leads to stasis of cilia.
– Likely a function of peroxide production • Capsule- does not appear to have same functions as other capsules, but is directly toxic if injected. • Superantigen enhances arthritic potential of M. arthritidis • _Adherance_ is very important in disease. Many different adhesins. |
|
|
What is a very common sequelae of Mycoplasma infections?
|
Arthritis, because the bacteria get into the joint and there is an immune response. In some cases there are immune modulators that enhance the arthritic properties of other bacteria.
|
|
|
What group of genes are very important to mycoplasma?
What |
Attachment and antigenic variation (cell envelope).
|
|
|
What is phase variation? What group of bacteria rely heavily on this technique?
|
Upregulating or downregulating gene expression.
Mycoplasma uses this a lot - in fact it can't help itself, because it's ability to use this variability is about all that it has. It will do it even when it shouldn't. |
|
|
What is an attachment organelle?
|
Mycoplasma motility- driven by the attachment organelle. Kinda like dogs towing a sled.
Several species have an attachment organelle that houses specific adhesins They move along inchworm style. |
|
|
How do mollicutes function as ciliastatics?
|
They colonize between the cilia and inhibit their ability to be cilia.
|
|
|
What are the two types of clinical conditions of mycoplasma?
|
• Invasive disease
– Septicemia – Arthritis – Hemolytic anemia • Mucosal disease – Pneumonia – Reproductive tract disease – Mastitis – Some gill disease in fish Aggressive _host respone_ is important in many mycoplasma diseases |
|
|
How are mycoplasmas transmitted?
|
As a general rule:
• All mycoplasmas are transmitted through direct contact or via droplets containing mucosal secretions. • Pathogens are typically introduced into a setting via introduction of clinically healthy _carrier animals_. |
|
|
Is there a vaccine for mycoplasma bovis?
|
• Aggressive pathogen- participates in BRDC with Mannheimia, etc.
• In mastitis, M. bovis should be considered upon elimination of other common causes. Other mycoplasma can also cause mastitis. • Antigenic variation in the species- vaccines can be designed for specific farms. |
|
|
Is mycoplasma bovis a primary disease or a predisposing agent…?
|
• Mycoplasma bovis can, by itself, cause respiratory
disease. • Often occurs when an initial stressor causes calves to develop traditional Bovine Respiratory Disease Complex (BRDC or shipping fever), and Mycoplasmosis develops seven to 14 days later. • Other cases where the pathogen is thought to predispose the host to infection by other resp. pathogens. |
|
|
What is the link between Mycoplasma bovis and mastitis?
|
• A major concern of local large animal vets is Mycoplasma mastitis in cattle.
• Source unclear, but animals who develop mastitis are culled. • Can be transmitted to nursing calves- leads to serious otitis |
|
|
What respiratory condition does Mycoplasma cause in bovids? What is the name of it?
|
Contagious bovine pleuropneumonia
• M. mycoides subsp. mycoides- isolated in 1898 – Member of a group of related strains- mycoides group- that infects different species. – Present in Asia, Africa, Middle East- eradicated from western countries (USA in 1890’s). – Aerosol transmission from infected animals- either diseased or asymptomatically infected – Sudden onset of high fever, respiratory distress, extended head and neck…mortality high- surviving animals become carriers. – Important to keep pathogen out of nonendemic regions. ** High priority pathogen for the World Org. for Animal Health- slaughter recommended/ required in nonendemic areas. Vaccines available, antibiotics can lead to carrier animals… |
|
|
What is the strain of mycoplasma that causes pneumonia in pigs?
|
Enzootic pneumonia of pigs
• M. hyopneumoniae- worldwide occurrence, pigs of all ages • high percentage of pigs can be affected, low mortality • Coughing, poor growth rates, respiratory distress • Antibiotics in feed can control outbreaks in a herd • Controlled by management- keep the pathogen out • Bacterin vaccines available. M. hyorhinis, M. hyosynoviae also cause diseases in pigs- arthritis, systemic inflammation. |
|
|
What pathology does mycoplasma cause in poultry?
|
• M. gallisepticum- respiratory disease in poultry
• Aerosol transmission- also vertical transmission: hen to chick via the egg (bacteria transmitted sexually). • Vaccines are available- controlled primarily through management. • Eggs can be dipped in antibiotic to eliminate the mycoplasma. (Other Mycoplasma also infect poultry) |
|
|
How does mycoplasma cause mycoplasma?
|
• Mycoplasma arthritidis-
produces superantigen. Leads to inflammation • Other mycoplasma can be cultured from joints- 20% of infected pigs can have mycoplasma in joint tissue. • Presence of pathogen leads to immune response, inflammation, arthritis. In chickens: Interaction with respiratory viruses may exacerbate pathol. |
|
|
What do you call parasites that colonze the surface of red blood cells?
How are these parasites usually transmitted. |
Erythrocytic parasites.
Transmission likely involves insect vectors. Hemotrophic mycoplasmas- hemoplasmas Historically from genera Haemobartonella, Eperythrozoon |
|
|
What causes a 1/4 of all anemias in cats?
|
Cats- 1/4 of all anemias are associated with Mycoplasma
haemofelis. Anemia results from host processing of infected cells. |
|
|
Can you culture hemoplasmas?
|
Hemotrophic mycoplasmas- hemoplasmas
Historically from genera Haemobartonella, Eperythrozoon Erythrocytic parasites- colonize the surface of red blood cells. Transmission likely involves insect vectors. Not cultivatable in vitro- transient bacteremias/anemias in vivo. Cats- 1/4 of all anemias are associated with Mycoplasma haemofelis. Anemia results from host processing of infected cells. |
|
|
How do you diagnose mycoplasma?
|
• Culture (if possible) can take 2 weeks- specific growth conditions (moist environment, high CO2, 37°C, rich medium plus serum for sterols)
• Sample prep can be tedious- all samples should be refrigerated • PCR, immunodiagnostics important Antibody assays/PCR can be used to distinguish among strains • Homologous (species-specific) antisera can be used in another assay similar to a Kirby-Bauer. • Fluorescent antibody can also be used • Latex agglutination |
|
|
What does mycoplasma cause in camelids?
What pathology does it cause? How can you diagnose it? |
Mycoplasma haemolamae- camelid hemotrophic mycoplasma
Mild to marked anemia in alpacas, etc. PCR assay developed at OSU- sensitive, specific. |
|
|
Can you vaccinate against Mycoplasma spp.?
|
There are vaccines available for many diseases caused
by Mycoplasma spp. Prevention of disease generally involves avoidance of pathogen, culling, vaccination. Antibiotics are useful in some cases. |
|
|
How do you treat Mycoplasma?
|
Mycoplasma is very difficult to treat because many
commonly used antibiotics do not work well. Antibiotics that target cell wall synthesis are ineffective- no cell wall… Effective antibiotic therapy is commonly lengthy. Relapses common, can lead to more severe disease. |
|
|
Is ureaplasma a commensal?
What pathologies does it cause? |
Commensal/parasite: Role in diseases often not
clear. U. diversum causes granular vulvitis of cattle Other species may be associated with diseases of the genital tract. Humans too. Require urea for growth. |
