• Share
  • Email
  • Embed
  • Like
  • Save
  • Private Content
Case Study 2: Don't Swim In The Pool (Final)

Case Study 2: Don't Swim In The Pool (Final)






Total Views
Views on SlideShare
Embed Views



1 Embed 4

http://academygenbioii.pbworks.com 4



Upload Details

Uploaded via as Microsoft PowerPoint

Usage Rights

© All Rights Reserved

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
Post Comment
Edit your comment

    Case Study 2: Don't Swim In The Pool (Final) Case Study 2: Don't Swim In The Pool (Final) Presentation Transcript

    • Don’t Swim in the Pool
      Patrick Racine
    • Background
      Several cases of skin rash infections reported at Hotel A in Bangor, Maine
      Feb. 18-27, 2000
      Infections related to low chlorine levels in the pool and hot tub
      >1.0 mg/L, less than state required 1-3 mg/L
      Sample of unknown pathogen taken from draining ear of 6 year old child and the pool filter
    • Patient History
      9 patients infected
      Had rash for 7 days (or less) or an outer ear infection
      All had spent time in either the pool or hot tub
      7 spent time in both
    • Signs and Symptoms
      Skin rash (folliculitis)
      Outer ear infection (otitisexterna)
    • Possible Culprits
      Originally there were 6 potential bacteria that could have caused the infections:
      Escherichia coli
      Pseudomonas aeruginosa
      Salmonella enterica
      Staphylococcus aureus
      Streptococcus pyogenes
    • Gram Stain
      A Gram stain differentiates bacteria based upon properties of their cell walls using a crystal violet stain
      Separated into 2 categories:
      Gram-positive (+) (dark blue/violet)
      Gram-negative (-) (red/pink)
      E. coli and S. aureus were Gram stained along with unknown bacteria for comparative reasons
    • Results of Gram Stain
      Gram stain showed that the unknown bacteria is Gram-negative
      Due to its red/pink color
      This eliminates 2 bacteria from being considered the cause of the outbreak
      Staphylococcus aureus
      Streptococcus pyogenes
      Both are Gram positive
    • Differential/Selective Media
      Two types of growth media used to inhibit or isolate growth of a microorganism
      Differential: Different microorganisms grown on the same media; distinguished by how each organism reacts to specific dyes and chemicals placed on media
      Selective: Allows growth of specific organism, inhibits others
    • Type of Growth Media Used
      Two options:
      MacConkey’s Agar
      Mannitol Salt Agar
      Because the suspect bacteria is Gram-negative, the best option was the MacConkey Agar
      Allows for growth of Gram-negative bacteria and inhibits the growth of most Gram-positive bacteria
    • Determining the Culprit Bacteria
      At this point, there were still four potential culprits remaining:
      Escherichia coli
      Pseudomonas aeruginosa
      Salmonella enterica
      • By using the information from the results of the growth media and research into the 4 potential bacteria, it was concluded that the culprit bacteria is Pseudomonas aeruginosa
    • Pseudomonas aeruginosa
      Aerobic respiration
      Due to production of arginine, undergoes anaerobic respiration as well
      Found in various environments including soil, water and hospitals
      Most abundant organism on Earth
      Rarely infects healthy individuals
      Prefers individuals with unhealthy immune systems
      Resistant to many antibiotics
    • Pseudomonas aeruginosa
    • Reasons for Selecting Culprit Bacteria
      • The infections occurred on the skin and outer ear, so Escherichia coli and Salmonella enterica were immediately eliminated
      • Escherichia coli and Salmonella enterica both cause infection of the digestive system
      • Although Staphylococcus aureusdoes cause various skin infections, including folliculitis, it does not cause the outer ear infection that is also associated with the culprit bacteria
      • This leaves Pseudomonas aeruginosa as the only logical culprit
    • Antimicrobial Susceptibility
      In order to choose a proper antibiotic to treat the infected patients, an antimicrobial test was conducted
      The effectiveness of 6 potential antibiotics were tested on the culprit bacteria
       Based on the results it was determined that the culprit bacteria was most sensitive to Gentamycin, making that antibiotic the best option
    • Antimicrobial Susceptibility Test
      The antibiotic that creates the largest zone of inhibition would be considered the most effective.