5.11 Lab Mycoplasma spp.

Question 1

mycoplasma cell shape

Answer 1

Variable cell shape!
* ‘pear shaped’
* Cocci
* Some filamentous

Question 2

mycoplasma colony shape

Answer 2

• Colonies form fried egg shape

Question 3

mycoplasma cell structure

Answer 3

• Smallest free-living organism
• Lack a cell wall; only have cell membrane

Question 4

mycoplasma living conditions/habitat

Answer 4

• Extremely fastidious
• Obligate parasites (extracellular)

Question 5

mycoplasma evolution

Answer 5

Mycoplasmas evolved from Gram positives

Question 6

where does mycoplasma get most of its nutrients

Answer 6

• Requires most nutrients from host

Question 7

how to replicate mycoplasma in the lab

Answer 7

• Agar and broth with many many ingredients
• Mycoplasmas grow slowly in vitro
• Penicillin inhibits growth of most other bacteria

Question 8

Why is diagnosis of mycoplasma difficult

Answer 8

• Polymicrobial infections often present but can also cause disease on their own.
• Many spp. are commensal
• Conventional culture-based diagnostic methods don’t work for
  Mycoplasma spp.
• PCR identification not offered in routine PCR panels (AHL)
• Antimicrobial susceptibility testing (AST) does not exist for some species e.g., M. cynos, M. felis
• Hemotropic mycoplasmas uncultivable

Question 9

how do we diagnose mycoplasma in the lab

Answer 9

• Culture – PPLO, SP4, Hayflick, many ‘in-house’ recipes
• PCR/qPCR + Sanger sequencing
• MALDI-TOF?
  > Mycoplasma bovis (Bokma et al 2020)
  > Avian mycoplasmas (Baudler et al 2019)
• Fluorescent antibody testing (FAT)
• Sometimes AST is available for the more common species (eg M. bovis)

Question 10

Why is mycoplasma treatment difficult?

Answer 10

• Polymicrobial infections are often present
• Lack of comprehensive treatment guidelines for small animals
• Intrinsically resistant to beta-lactams, Trimethoprim and Sulfamethoxazole