Mycoplasmas

Question 1

Do the bacteria in the family Mollicutes have a cell wall?

Answer 1

No

Question 2

What is the mycoplasma cell morphology?

Answer 2

• pleomorphic: round, flask-like and filamentous forms
• plastic
• filterable (0.45 um)

Question 3

Mycoplasma is one of the ______

Answer 3

Smallest self-replicating prokaryotes and living organisms

Question 4

What is the first mycoplasma found in history? Which animal species was this pathogen first found? What was the impact of this mycoplasma on the agricultural development?

Answer 4

M. mycoides subsp. mycoides

• bovine, is the etiologic agent of contagious bovine pleuropneumonia
• spread in the US lead to development of Bureau of Animal Industry of USDA in 1884
• is completely eradicated from the US

Question 5

Are mycoplasmas parasites? Are mycoplasmas viruses?

Answer 5

They are not parasites, but do have a parasitically or commensal life style

• do not replicate in the environment
• rely on host for nutrients
• colonies have a fried egg appearance

Question 6

Fastidious growth requirements

Answer 6

• sterols needed for growth
• can be cultured in embryonated eggs, cell-culture systems, right medium
• aerobic, capnophilic, microaerophilic

Question 7

What was the first mycoplasm species to have the full genome sequenced?

Answer 7

M. genitalium

• genome size is 580 kb, 482 genes
• low G+C content
• UGA codes Trp

Question 8

Minimal genome project

Answer 8

Hamilton Smith, Crag Venter

- M. laboratorium, 382 genes

Question 9

Are mycoplasmas easy to be cultured?

Answer 9

Yes

Question 10

What does mycoplasma colony look like?

Answer 10

Fried egg

Question 11

What are the most important bovine mycoplasmas?

Answer 11

• M. mycoides subsp. mycoide
• M. bovis
• M. californicum
• M. bovoculi

Question 12

What are the important avial mycoplasmas?

Answer 12

• M. gallisepticum
• M. synoviae
• M. meleogridis
• M. iowae

Question 13

Mycoplasmas are one of the top 5 diseases threatening US ______

Answer 13

Poultry

Question 14

What are the most important swine mycoplasmas?

Answer 14

• M. hyopneumoniae
• M. hyorhinis
• M. hyosynoviae

Question 15

What are the most important goats/sheep mycoplasmas?

Answer 15

• M. aglatiae
• M. cariocolum subsp. Capripneumoniae
• M. cariocolum subsp. Capricolum
• M. mycoides subsp. America, mycoides
• M. mycoides subsp. Capri

Question 16

How to diagnose mycoplasma?

Answer 16

Based on bacterial culture, serology, and PCR

• specimens should be collected early and delivered to lab within 48 hrs
• serology includes specific antibody detection, rapid serum agglutination/latex agglutination, hemagglutination inhibition, ELISA

Question 17

Are there any myoplasma vaccines available?

Answer 17

Yes, for MG, MS, M. hyopneumoniae, M. bovis

- each state’s vaccine policy is different

Question 18

Impact of co-infections of mycoplasmas with other pathogens?

Answer 18

Occurs in M. bovis

- co-infection with other respiratory pathogens (BVDV, pasteruella, and M. hemolytica) occurs frequently

Question 19

What are the common infected tissues/organs?

Answer 19

Mucosal locations

• lungs
• synovial joints
• urogenital tract (vertical transmission)
• mastitis

Question 20

Which mycoplasmas cause mastitis in bovine?

Answer 20

• M. bovis

- M. californicum

Question 21

Which mycoplasmas cause respiratory diseases in chicken and turkey? Bovine? Swine?

Answer 21

Poultry: M. gallisepticum, M. meleagridis
Bovine: M. mycoides, M. bovis
Swine: M. hypopneumoniae

Question 22

Which mycoplasmas cause arthritis in avian? Swine? Bovine?

Answer 22

Avian: M. gallisepticum, M. synoviae, M. meleagridis
Swine: M. hyosynoviae
Bovine: M. bovis

Question 23

How are mycoplasmas transmitted?

Answer 23

• inhalation
• man’s intervention (ex: AI)
• spread thru egg
• venereal disease (M. meleagridis, iowae)

Question 24

How should mycoplasmas be controlled?

Answer 24

• stress reduction
• good management
• quarantine new animals in the herd
• sanitation of milking equipment
• monitor/removal of reactor flocks
• periodic examination of culled lungs

Question 25

How should mycoplasmas be treated?

Answer 25

• M. bovis: antibiotics are usually unsuccessful, positive animals should be removed
• M. hypopneumoniae: continual or pulse-dosing antimicrobial therapy

Question 26

How do mycoplasmas reach target tissues?

Answer 26

Epithelial surfaces

- respiratory, urogenital, joints, mastitis

Question 27

How are mycoplasmas motile?

Answer 27

Gliding motility
- may assist the mycoplasma to reach its target and to breach certain physical defenses such as ciliary activity and the mucin layer in the respiratory tract

Question 28

How to mycoplasma adhere to host tissue?

Answer 28

Adhesin and adhesin-like protiens

• some have a terminal structure, flask-like shape
• cytoskeleton structure could function in localizing adhesins, adjusting cell shape, and gliding motility

Question 29

How do mycoplasmas evade host defense?

Answer 29

• high frequency of antigenic variation
• variable surface proteins is used to achieve extensive antigenic variation
• adherence to neutrophils and macrophages impairs phagocytic activities –> polysaccharide capsule of M. mycoides and M. diopar prevents phagocytosis
• molecular mimicry: antigens share sequence homology to host protein
• induce cytokine production to trigger anti-self antibody production

Question 30

U. diversum infects bovine genitourinary tract leading to ______, ______, ______

Answer 30

Vulvitis, infertility, abortion