PAB Medical Bacteriology

• Who is most at risk for Acinetobacter infections?

  Immunocompromised individuals
• Which strain of Pseudomonas aeruginosa is highly virulent?

  Strain PA14
• How does Acinetobacter's antimicrobial resistance impact treatment options?

  It limits effective treatment choices
• What type of infections does Acinetobacter primarily cause?

  Healthcare-associated infections
• What type of bacteria is Pseudomonas aeruginosa classified as?

  Opportunistic bacteria
• What are the key features of the microorganisms shown in the image?

  • Rod-shaped
  • Appear to be in clusters or groups
  • Have a smooth, uniform surface
• Which bacteria inhabit the Perineum/Lower Limbs?

  Fecal flora, enterococci, coliforms
• What type of microorganisms are shown in the image?

  Bacteria
• How could these microorganisms be observed in more detail?

  • Use a scanning electron microscope (SEM) to obtain a high-resolution 3D image
  • Stain the microorganisms to enhance contrast and visibility
  • Perform biochemical tests to identify the specific species
• What type of bacteria is Acinetobacter?

  Gram-negative bacteria
• What color are the microorganisms shown in the image?

  Pink
• How does Acinetobacter differ from Pseudomonas?

  Acinetobacter causes mostly healthcare-associated infections
• What are the main mechanisms of antibiotic resistance shown in the image?

  • Decreased porin expression
  • Methylation of 30S rRNA
  • β-lactamase enzymatic inactivation
  • Aminoglycoside modifying enzymes (AMEs)
  • Topoisomerase IV / DNA gyrase mutations
  • Increased efflux pump expression
  • Modification/loss of LPS
• What are the common bacterial types in the Skin?

  1. epidermidis, S. aureus, diphtheroids, yeasts
• Which strain of Pseudomonas aeruginosa is considered to have moderate virulence?

  Strain PAO1
• What is the significance of Pseudomonas aeruginosa in clinical settings?

  • Opportunistic pathogen
  • Affects vulnerable populations
  • Causes infections in wounds and burns
• Who are the most vulnerable individuals affected by Pseudomonas aeruginosa?

  Patients with cystic fibrosis (CF)
• How do the strains PAO1 and PA14 of Pseudomonas aeruginosa differ?

  They show different levels of virulence
• What are common resistance mechanisms in pathogens?

  Decreased antibiotic entry, target modification, enzyme inactivation, increased efflux pumps
• What are the common colonizers found in the large intestine?

  • Fecal flora
  • Bacteroides spp.
  • Clostridia
  • Streptococci
  • 5% coliforms
  • Enterococci
• How does methylation of 30S rRNA contribute to antibiotic resistance?

  Methylation of 30S rRNA decreases antibiotic binding, reducing the effectiveness of antibiotics that target the ribosomal subunit (e.g. aminoglycosides).
• What type of bacteria is Burkholderia?

  Gram-negative bacteria
• Compare Burkholderia pseudomallei with Pseudomonas and Acinetobacter in terms of their common environments and resistance.

  • Pseudomonas: More common in healthcare settings
  • Acinetobacter: Highly resistant to antibiotics
  • Burkholderia pseudomallei: Mostly environmental, shows variable resistance
• What are the common colonizers found in the stomach?

  Virtually sterile, Acid-tolerant lactobacilli
• In which individuals are nosocomial infections particularly common?

  Immunocompromised individuals
• What are common colonizers in the Nose/Throat?

  Oral streptococci, S. pneumoniae, Neisseria spp
• How do aminoglycoside modifying enzymes (AMEs) contribute to antibiotic resistance?

  AMEs decrease affinity for ribosomal subunit (Aminoglycosides)
• What is the role of the type III and VI secretion systems in B. pseudomallei?

  They inject toxins into host cells
• What are the common bacterial types in the Uretra/Vagina?

  1. epidermidis, streptococci, coliforms
• What are the reference strains of Pseudomonas aeruginosa mentioned?

  • Strain PAO1: moderate virulence
  • Strain PA14: highly virulent
• What are the common colonizers found in the perineum and lower limbs?

  Fecal flora, Enterococci, Coliforms, Anaerobes
• Where is Burkholderia pseudomallei commonly found?

  In soil and water in Southeast Asia and northern Australia
• What is the mechanism of antibiotic resistance shown as "Decreased porin expression"?

  Decreased antibiotic entry (β-lactams, chloramphenicol)
• What are colonization sites in the body?

  Specific areas where bacteria normally reside
• What does widespread multidrug resistance require for treatment strategies?

  Complex treatment strategies
• What are the common colonizers found in the nose and throat?

  Oral streptococci, S. pyogenes, S. pneumoniae, Neisseria spp., S. epidermidis, H. influenzae
• What is the community risk level for Pseudomonas?

  Low
• What is the significance of colonization sites?

  They indicate where bacteria normally reside
• How can Pseudomonas aeruginosa enter the body?

  Through wounds and burns
• What are the common colonizers found in the urethra and vagina?

  • S. epidermidis
  • Diphtheroids
  • Streptococci
  • Coliforms
  • Anaerobes