Gram -ve

• What are intrinsic host factors that prevent microbial colonization on oral surfaces?

  Mucosal barrier, salivary flow, tongue movements

  
• How does the mucosal barrier prevent microbial colonization?

  It dislodges attached organisms through desquamation
• What role does salivary flow play in microbial colonization?

  It creates dynamic patterns in oral niches
• How do tongue and cheek movements affect biofilms?

  They physically dislodge biofilms from surfaces
• What are the defense factors found in saliva?

  Non-specific and specific factors like IgA
• What is meant by 'colonization resistance' in microbial flora?

  It prevents invading organisms from establishing
• What host resources do oral bacteria utilize for nutrition?

  • Remnants of host diet (sucrose, starch)
  • Salivary constituents (glycoproteins, minerals, vitamins)
  • Gingival crevicular fluid (proteins)
  • Gaseous environment (low oxygen levels)
• What microbial resources do oral bacteria utilize for nutrition?

  • Extracellular products from neighboring bacteria
  • Intracellular food storage (glycogen granules)
• What is the plaque biofilm?

  A microbial community in an extracellular matrix
• What does quorum sensing allow bacteria to do?

  Share information about cell density and adjust genes

  
• What are quorum-sensing molecules?

  Chemicals that maintain population composition in biofilms

  
• What is the role of specific gene activation in biofilms?

  It can produce virulence factors or reduce metabolism
• Where is Pseudomonas aeruginosa commonly found?

  In moist environments in hospitals
• What are the morphological characteristics of Pseudomonas aeruginosa?

  Oxidase positive, motile, rod-shaped
• What pigments does Pseudomonas aeruginosa produce?

  Pyocyanin and pyoverdine
• What is the role of LPS in Pseudomonas aeruginosa?

  It aids in antibiotic tolerance and biofilm formation
• How do pili contribute to the pathogenicity of Pseudomonas aeruginosa?

  They allow attachment to host epithelial cells
• What is the function of exotoxin A produced by Pseudomonas aeruginosa?

  It causes tissue necrosis
• What are the exoenzymes produced by Pseudomonas aeruginosa and their functions?

  • Exoenzyme S: Inhibits phagocytosis
  • Exoenzyme T: Impairs wound healing
  • Exoenzyme U: Destroys host cell membranes
  • Exoenzyme Y: Disrupts cellular signaling
• At what temperature does Pseudomonas aeruginosa grow?

  42°C
• What do colonies of Pseudomonas aeruginosa look like on nutrient agar?

  Surrounded by bluish-green coloration

  
• What is the appearance of Pseudomonas aeruginosa on blood agar?

  Greyish and hemolytic colonies

  
• What do pale yellow colonies on MacConkey agar indicate?

  Presence of Pseudomonas aeruginosa

  
• What infections is Pseudomonas aeruginosa associated with?

  • Catheter-associated urinary tract infections (CAUTI)
  • Biofilms in cystic fibrosis patients
  • Wound and burn infections
  • Folliculitis from hot tubs
  • Respiratory infections (pneumonia)
  • Green nail syndrome
  • Eye infections
  • Ear infections
  • Hemorrhagic necrosis in sepsis
• How does Pseudomonas aeruginosa develop resistance to antibiotics?

  It rapidly develops resistance with single drug use
• What is the primary therapy for Pseudomonas aeruginosa infections?

  Ceftazidime with an aminoglycoside
• Where is Burkholderia pseudomallei commonly found?

  In soil, fresh water, and rice paddies
• What are the characteristics of Burkholderia pseudomallei?

  Motile, oxidase-positive, non-lactose fermenter
• What is the appearance of Burkholderia pseudomallei colonies?

  Mucoid, smooth to rough, cream to orange

  
• What disease does Burkholderia pseudomallei cause?

  Melioidosis (Whitmore’s disease)
• What is the initial therapy for melioidosis?

  10–14 days with ceftazidime or imipenem
• What is the eradication therapy for melioidosis?

  Sulfamethoxazole–trimethoprim or doxycycline
• What is the natural habitat of Neisseria gonorrhoeae?

  Humans are the only natural host
• What disease does Neisseria gonorrhoeae cause?

  Gonorrhea, a sexually transmitted infection
• What are the characteristics of Neisseria gonorrhoeae?

  Diplococcus, non-spore-forming, oxidase positive
• How do gonococci evade the immune system?

  By producing IgA proteases that inactivate IgA
• What is the treatment for gonorrhea?

  β-lactamase-stable cephalosporins like Ceftriaxone
• What is the main reservoir for Neisseria meningitidis?

  The nasopharynx in healthy individuals
• How is Neisseria meningitidis transmitted?

  Through droplet spread from close contact
• What are the characteristics of Neisseria meningitidis?

  Capsulated, ferments glucose and maltose