medical microbiology

• What type of bacteria are Mycoplasmas classified as?


  Gram-positive bacteria
• What are the characteristics of Firmicutes?


  They are low GC gram-positive bacteria.
• What are the main genera of lactic acid bacteria?


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

  Clostridium and Bacillus
• What is the defining feature of Mycoplasmas?


  They completely lack a cell wall and only have a plasma membrane.
• Why do Mycoplasmas stain gram-negative?


  Because they lack a cell wall.
• What strengthens the plasma membrane of Mycoplasmas?


  The inclusion of sterols.
• What is the size range of coccoid Mycoplasma cells?


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


  They can take on various shapes and sizes.
• What is the primary growth requirement for Mycoplasmas?


  They require sterols for growth.
• What type of colonies do Mycoplasmas form on solid agar?


  Fried egg-shaped colonies.
• What is the genome size of Mycoplasma pneumoniae?


  816 kbp.
• How does the genome size of Mycoplasma genitalium compare to other organisms?


  It has the smallest known genome of any self-replicating organism at 580 kbp.
• What evolutionary trend has been observed in Mycoplasmas?


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


  They are parasites of animal mucous membranes.
• How are Ureaplasma classified in relation to Mycoplasmas?


  They are a type of T-Strain Mycoplasmas.
• What is the primary metabolic requirement of Ureaplasma?


  They require cholesterol and urea for growth.
• What is the significance of urease in Ureaplasma?


  It converts urea into ammonia and CO2.
• What type of bacteria is Acholeplasma?


  Facultative aerobes that can grow in the absence of sterols.
• What is the habitat of Anaeroplasma?


  They inhabit the bovine or ovine rumen.
• What is the shape and motility of Spiroplasma?


  They are helical and motile.
• 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 does Mycoplasma pneumoniae adhere to respiratory epithelial cells?

  It uses polar tip organelles and specific adhesion proteins.
• What is the role of hydrogen peroxide produced by Mycoplasma pneumoniae?

  It is responsible for initial cell disruption in the respiratory tract.
• How is Mycoplasma pneumoniae transmitted?

  Through close personal contact via respiratory droplets.
• What diagnostic methods are used for Mycoplasma pneumoniae?

  Clinical symptoms, serological tests, and DNA tests (PCR).
• Why is accurate diagnosis important for Mycoplasma pneumoniae infections?

  Because it is resistant to antibiotics that act on the cell wall.
• What antibiotics are commonly used to treat Mycoplasma pneumoniae infections?

  Erythromycin, doxycycline, azithromycin, and levofloxacin.
• What are the characteristics of Mycoplasma genitalium and related species?


  • Causes non-gonococcal urethritis (NGU)
  • Associated with infertility in men and cervicitis in women
  • Transmitted by direct venereal contact
  • Detection relies on molecular techniques (PCR)
• What is the treatment for Mycoplasma genitalium infections?


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


  Antibiotic resistance is high.
• What are the main characteristics of lactic acid bacteria?


  • Produce lactic acid from fermentation
  • Non-spore forming and non-motile
  • Aerotolerant anaerobes
  • Require many vitamins and amino acids
• What is the fermentation product of lactic acid bacteria from glucose?


  Two moles of lactic acid.
• What is the difference between homofermentative and heterofermentative lactic acid bacteria?


  Homofermentative produces only lactic acid, while heterofermentative produces lactic acid, ethanol, and CO2.
• What are the main genera of lactic acid bacteria and their products?

  • Lactobacillus bulgaricus: Bulgarian buttermilk, yogurt
  • Streptococcus thermophilus: Emmental, Cheddar, and Italian cheeses
  • Streptococcus lactis: Cultured buttermilk, cottage cheese
• 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 the glycolytic pathway.
• Which species is known for producing Bulgarian buttermilk and yogurt?

  Lactobacillus bulgaricus
• What is the primary product of Lactobacillus lactis?


  Acid