week 3

• What is the significance of the term "Firmicutes" in relation to Mycoplasmas?


  Firmicutes refers to low GC gram-positive bacteria, which includes Mycoplasmas.
• Which bacteria are classified as non-spore forming low GC gram-positive bacteria?


  Streptococcus, Lactobacillus, Staphylococcus, Listeria, Mycoplasma
• Which bacteria are classified as spore-forming bacteria?

  Clostridium and Bacillus
• What is a key characteristic of Mycoplasmas regarding their cell structure?


  Mycoplasmas completely lack a cell wall and only have a plasma membrane.
• Why do Mycoplasmas stain gram-negative despite being phylogenetically related to low GC gram positives?


  They lack a cell wall, which is why they stain gram-negative.
• What is the size range of coccoid Mycoplasma cells?


  0.12µm - 0.25µm in diameter
• What does the term "pleomorphic" refer to in Mycoplasmas?


  Pleomorphic refers to their ability to take on various shapes and sizes.
• What is the primary growth requirement for Mycoplasmas?


  All require sterols except Acholeplasma, Asteroleplasma, and Mesoplasma.
• What type of growth factors do Mycoplasmas require?


  They require vitamins, fatty acids, amino acids, purines, and pyrimidines.
• How do Mycoplasmas appear when grown on solid agar?


  They form a fried egg-shaped colony and embed into the media.
• What is the genome size of Mycoplasma pneumoniae?


  816 kbp
• What is significant about Mycoplasma genitalium's genome?


  It has the smallest known genome of any self-replicating organism at 580 kbp.
• How does the genome size of Mycoplasma pneumoniae compare to Escherichia coli?


  Mycoplasma pneumoniae has a genome of 816 kbp, while Escherichia coli has 5440 kbp.
• What evolutionary trend has been observed in Mycoplasmas regarding their genome size?


  Multiple reductions in genome size have occurred during their evolution.
• What type of environment do Mycoplasmas typically inhabit?


  They are parasites of animal mucous membranes.
• What is the oxygen requirement for Ureaplasma (T-Strain Mycoplasmas)?


  They are microaerophilic and require cholesterol and urea for growth.
• What is the primary function of urease in Ureaplasma?


  Urease converts urea into ammonia and CO2.
• How are Ureaplasma infections transmitted?


  They are transmitted by sexual contact and can be vertically transmitted from mother to offspring.
• What is the treatment for Ureaplasma infections in the UK?


  Doxycycline pretreatment followed by azithromycin or moxifloxacin.
• What is the significance of antibiotic resistance in Mycoplasma genitalium?


  Antibiotic resistance is high, making treatment challenging.
• What are the main genera of lactic acid bacteria?

  Streptococcus, Lactobacillus, Staphylococcus, Listeria, Mycoplasma
• What do lactic acid bacteria produce as a product of fermentation?


  Lactic acid
• How do lactic acid bacteria obtain energy?


  They obtain energy by substrate level phosphorylation, not by oxidative phosphorylation.
• What is the fermentation pattern of homofermentative lactic acid bacteria?


  They produce a single fermentation product, lactic acid.
• What is the fermentation pattern of heterofermentative lactic acid bacteria?


  They produce lactic acid, ethanol, and carbon dioxide.
• What are the main functions and products of key lactic acid bacteria species?

  • Lactobacillus bulgaricus: Bulgarian buttermilk, yogurt, kefir
  • Lactobacillus acidophilus: Acidophilus buttermilk
  • Streptococcus thermophilus: Emmental, Cheddar, and Italian cheeses, yogurt
  • Streptococcus diacetilactis: Sour cream, butter, cheese
  • Streptococcus lactis: Cultured buttermilk, cottage cheese
• What are the characteristics of lactic acid bacteria?


  • Non-spore forming
  • Non-motile
  • Aerotolerant anaerobes
  • Limited biosynthetic capability
  • Tolerant of acid
• What is the significance of lactic acid production in lactic acid bacteria?


  • Eliminates competition
  • Used in selective media
  • Important for food preservation
• What are the fermentation pathways used by lactic acid bacteria?


  • Embden-Meyerhof pathway for homofermentative
  • Pentose phosphate pathway for heterofermentative
• What are the growth conditions for lactic acid bacteria?


  • Grown on media containing yeast, peptone, and fermentable carbohydrates
  • Growth not affected by air presence
• What are the characteristics of Mycoplasma pneumoniae?


  • Causes primary atypical pneumonia
  • Symptoms range from mild flu-like to severe pneumonia
  • Communicated through respiratory droplets
• What are the diagnostic methods for Mycoplasma pneumoniae?


  • Clinical symptoms and X-Ray
  • Serological tests (e.g., ELISAs)
  • DNA test (PCR) for definitive diagnosis
• What are the treatment options for Mycoplasma pneumoniae infections?


  • Erythromycin, doxycycline, azithromycin, levofloxacin
  • Erythromycin is effective against legionella
• What are the implications of Mycoplasma genitalium infections?


  • Causes non-gonococcal urethritis
  • Associated with infertility in men and women
  • Transmitted through direct contact and vertically during delivery
• What are the challenges in detecting Mycoplasma genitalium?


  • Detection relies on molecular techniques (PCR)
  • Difficulty in culturing the organism
• What is the significance of antibiotic resistance in Mycoplasma genitalium?


  • High antibiotic resistance complicates treatment
  • Resistance to macrolides and fluoroquinolones
• What are the main fermentation products of lactic acid bacteria?


  Glucose, lactic acid, ethanol, and carbon dioxide
• What is the difference between homofermentative and heterofermentative lactic acid bacteria?


  • Homofermentative: Produces a single fermentation product (lactic acid).
  • Heterofermentative: Produces lactic acid and other products (mainly CO2 and ethanol) using the pentose phosphate pathway.
• What is the Embden-Meyerhof pathway associated with?


  It is associated with glycolysis.
• Which species is known for producing Bulgarian buttermilk and yogurt?

  Lactobacillus bulgaricus