SAS 2

• Thick-walled Organisms

  • Free-living
  • Non-free living
• Free-living Thick-walled Organisms

  • Gram-Positive
  • Gram-Negative
  • Acid Fast
• Thin-walled Organisms

  • Spirochetes
• Wall-less Organisms

  • Mycoplasma

  
• Bacteria


  Singular - bacterium<|>Are single-cell and unicellular organisms<|>Most are PATHOGENIC<|>Gram positive and Gram negative<|>Three general shapes: cocci, bacilli and spiral

  
• Terms to Define

  • DOC
  • MOA
  • MOT
  • Causative agent
  • Reservoir
  • Vector
  • Spores
  • Lactose fermenting organisms
  • Virulence
  • Facultative
  • Obligate
• Streptococci

  Spherical, gram-positive bacteria that typically appears in chain and is encapsulated<|>Alpha, Beta and Gamma hemolysis (most are hemolytic)<|>(-) Coagulase test ; (-)Catalase test

  
• Alpha-hemolysis

  • Streptococcus pneumoniae
  • Streptococcus viridians
  • Streptococcus mutans
• Beta-hemolysis

  • Streptococcus pyogenes
  • Streptococcus agalactiae
• Gamma-hemolysis


  • Streptococcus bovis
  • Enterococci
• Lancefield Grouping

  • Group A Streptococcus
  • Group B Streptococci
  • Group C Streptococci
  • Group D Streptococci
  • Unclassified Streptococci
• Group A Streptococcus

  Suppurative: Respiratory Tract, Skin<|>Non-suppurative: Exotoxin A, M Protein
• Group B Streptococcus

  Normal flora of vagina<|>Causes neonatal sepsis and meningitis<|>Treatment: Ampicillin + Gentamicin
• Group D Streptococcus

  • Enterococci
  • Streptococcus bovis
• Unclassified Streptococcus

  Streptococcus viridians<|>Streptococcus mutans
• Streptococcus pneumoniae

  Pneumococcus<|>Lancet-shaped diplococci<|>Virulence Factor: Capsule (Quellung reaction)<|>Prevention: PCV
• Staphylococcus aureus

  Grapelike clusters; smooth round, yellow colonies<|>Grow at temp 15-45°C and at NaCl conc. As high as 15%<|>Positive Coagulase; Positive Catalase and is Beta-hemolytic<|>Primary cause of nosocomial infections<|>Associated with tampon use
• Staphylococcus aureus Virulence Factors

  Lipase: causes boils, furuncle, carbuncle<|>Exfloliatin: causes Staphylococcal scalded skin syndrome<|>Enterotoxin B: causes food poisoning, toxic shock syndrome<|>β-lactamase/ penicillinase: antibiotic resistance
• Staphylococcus epidermidis


  Part of the normal human flora, typically the skin flora<|>Facultative anaerobic bacteria
• Staphylococcus saprophyticus

  Second cause of UTI in sexually active women<|>Coagulase negative
• Gram-Negative Bacteria

  • Enterobacteriaceae
  • Vibrionaceae
  • Bacilli
  • Cocci
  • Anaerobic organisms
  • Aerobic organism
• Gram-Negative Bacteria

  • All are facultative anaerobes, oxidase negative
  • All are motile, EXCEPT Shigella, Klebsiella, Yersinia
  • Ferment glucose with acid production
  • Reduce nitrates into nitrites
  • Oxidase negative; Catalase positive
  • They grow on peptone or meat extract media: Mac Conkey's Agar
• Escherichia coli


  Colon bacillus<|>Most abundant aerobic flora of the colon<|>Most common flora of the colon: anaerobes<|>Common indicator of fecal contamination of water<|>Presentation: most common cause of UTI<|>Treatment: Nitrofurantoin, Fosfomycin, Fluroquinolones
• Klebsiella pneumoniae

  Capsulated, non-motile, non-spore former<|>Lactose fermenting; Facultative anaerobe<|>Present in respiratory tract and feces of about 5% of normal individuals<|>Second most common cause of Gram negative sepsis, Pneumonia (HAP)
• Encapsulated Bacteria

  • Streptococcus pneumoniae
  • Klebsiella pneumoniae
  • Haemophilus influenzae
  • Pseudomonas aeruginosa
  • Neisseria meningitidis
  • Cryptococcus neoformans (fungi)
• ESKAPE Bacteria

  • Enterococcus faecium
  • Staphylococcus aureus
  • Klebsiella pneumoniae
  • Acinetobacter baumanii
  • Psedomonas aeruginosa
  • Enterobacter spp.
• Salmonella Typhi

  Reservoir: poultry and dairy products<|>Diagnosis: Widal test, Typhidot