Mycoplasma

• What type of bacteria are mycoplasmas classified as?

  Gram positive bacteria
• Why do gram-positive bacteria not retain crystal violet stain?

  Because the crystal violet is not stuck in the peptidoglycan
• What are the two main categories of gram-positive bacteria?

  • Non-spore forming bacteria
  • Lactic acid bacteria: Streptococcus, Lactobacillus, Staphylococcus, Listeria, Mycoplasma
  • Spore forming bacteria: Clostridium, Bacillus
• What is the GC content characteristic of firmicutes?

  Low GC gram positive bacteria
• Which group of bacteria is known for having a high GC content?

  Actinobacteria
• What is unique about mycoplasma in terms of cell structure?

  They completely lack a cell wall
• How are mycoplasmas related to gram-positive bacteria despite lacking a cell wall?

  Gene sequencing shows they are related
• What is the effect of osmotic lysis on mycoplasmas?

  They are sensitive to osmotic lysis
• What strengthens the plasma membrane of mycoplasmas?

  The inclusion of sterols
• What are lipoglycans in mycoplasmas involved in?

  They help avoid the immune response
• What is the size range of concord cells?

  0.12 µm to 0.25 µm in diameter
• Why are mycoplasmas considered pleomorphic?

  Because they come in different shapes
• What is the significance of mycoplasmas being non-motile?

  Most are non-motile, except some human and animal pathogens
• What type of organisms do mycoplasmas primarily parasitize?

  Eukaryotes
• What are the growth factor requirements for mycoplasmas?

  They have complex growth factor requirements due to limited biosynthetic capabilities
• Which mycoplasmas do not require sterols for growth?

  Acholeplasma, Asteroleplasma, and Mesoplasma
• How do mycoplasmas appear when grown on solid agar?

  They form a fried egg-shaped colony
• What is the GC content range for mycoplasmas?

  Approximately 25-35%
• Which mycoplasma has the smallest known genome?

  Mycoplasma genitalium
• What is the size of the genome of Mycoplasma genitalium?

  580 kbp
• How does the genome size of Mycoplasma pneumoniae compare to that of E. coli?

  Mycoplasma pneumoniae has a genome of 816 kbp, while E. coli has 5440 kbp
• What evolutionary trend has occurred in the genome of mycoplasmas?

  Multiple reductions in genome size have occurred
• What are the characteristics of mycoplasmas?

  • Require cholesterol
  • Parasites of animal mucous membranes
  • Facultative anaerobes
  • Over 60 species recognized
• What is the role of urease in mycoplasmas?

  It converts urea to ammonia and CO2
• What is a common cause of non-gonococcal urethritis (NGU)?

  Mycoplasma genitalium
• How is Mycoplasma genitalium transmitted?

  By direct venereal contact
• What is the significance of mycoplasmas in the pharmaceutical industry?

  They are difficult to sterilize in liquids and are common contaminants
• What is the treatment for Mycoplasma pneumoniae infections?

  Erythromycin, doxycycline, azithromycin, or levofloxacin
• What complications can arise from Mycoplasma genitalium infections in women?

  Associated with cervicitis and endometriosis
• What is the recommended treatment for Mycoplasma genitalium in the UK?

  Doxycycline pretreatment followed by azithromycin or moxifloxacin
• What are the symptoms of Mycoplasma pneumoniae infection?

  • Mild flu-like symptoms: headache, sore throat, cough
  • Severe pneumonia: fever, chills, malaise
  • Protracted course with gradual resolution
• How is Mycoplasma pneumoniae diagnosed?

  Through clinical symptoms, X-ray, and PCR tests
• Why are serological tests not commonly used for diagnosing Mycoplasma pneumoniae?

  They are considered old-fashioned and not useful
• What is the challenge in culturing Mycoplasma pneumoniae?

  Culturing is slow and not very useful
• Why is accurate diagnosis of Mycoplasma pneumoniae important?

  Because it is resistant to antibiotics that act on the cell wall
• What antibiotics are ineffective against Mycoplasma pneumoniae?

  Penicillins and cephalosporins
• What is the role of hydrogen peroxide produced by Mycoplasma pneumoniae?

  It is thought to be responsible for initial cell disruption in the respiratory tract
• What is the significance of the polar time organelles in Mycoplasma pneumoniae?

  They are involved in specific adhesion to respiratory epithelium cells
• What is the common age range for individuals affected by Mycoplasma pneumoniae?

  Individuals aged 5-20 years old
• What type of pneumonia does Mycoplasma pneumoniae cause?

  Primary atypical pneumonia (walking pneumonia)