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Case Study 1: Peanut Butter is Tainted

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Case Study 1: Peanut Butter is Tainted

  1. 1. Case Study 1: Peanut Butter is Tainted<br />Suma and Kathryn<br />
  2. 2. Background Information<br />425 people from 44 states were ill <br />Diarrhea, fever, abdominal cramps<br />Illness usually lasted 4-7 days, some cases of diarrhea were so severe patient needed to be hospitalized<br />Out of 351, 71 (20%) were hospitalized<br />No deaths<br />Onset dates ranged from August 1st to February 16th, and 67% of cases occurred after December 1st<br />
  3. 3. Affected System<br />Digestive system<br />
  4. 4. Parts that could be affected<br /><ul><li> Stomach
  5. 5. Small intestine
  6. 6. Large intestine</li></li></ul><li>Patient PB<br />Stomach cramping<br />Diarrhea<br />Moderately high temperature<br />16 hours prior to onset, peanut butter sandwich had been consumed<br />Escherichia coli<br />Pseudomonas aeuroginosa<br />Salmonella enetrica<br />Staphylococcus aureus<br />Streptococcus pyogenes<br />Haemophilusinfluenzae<br />Symptoms and History<br />Possible Culprits<br />
  7. 7. Gram stain<br />Procedure<br />Add bacteria sample, E.coli(negative control), and S. aureus (positive control)to individual drops of water<br />Let dry<br />Heat fix slide<br />Cover smears with crystal violet dye for one minute, then rinse with DI water<br />Repeat with Gram’s iodine, but rinse with decolorizer acetone alcohol<br />Repeat with safranin, rinse with DI water<br />Blot dry, view using oil immersion<br />
  8. 8. Results (Gram stain)<br />Expected results<br />What do these results mean?<br />Pink- Gram negative<br />Purple- Gram positive<br />Eliminate S. aureus and S. pyogenus<br />Patient sample (1000x)<br />E. Coli (1000x)<br />S. aureus(1000x)<br />
  9. 9. Selective/differential plate<br />Procedure<br />Use MacConkey Agar because patient sample is gram negative<br />Spread E. coli (positive control), S. aureus (negative control), and patient sample in a V-formation on the plate<br />Incubate<br />
  10. 10. Results (selective/differential)<br />Expected Results<br />Reddish pink- lacpositve, gram negative<br />Whitish clear- lac negative, gram negative<br />No growth- gram positive<br />E. coli- pinkish red<br />S. aureus – no growth<br />Patient- whitish clear<br />What do these results mean?<br /><ul><li>eliminate E. coli</li></li></ul><li>Antimicrobial Susceptibility Test<br />Coat a plate with a thin film of bacteria, making sure not to miss any spots<br />Place six antibiotic discs around the edges of the plate, evenly spaced apart<br />Tetracyclin<br />Penicillin<br />Streptomycin<br />Vancomycin<br />Gentamicin<br />Chloramphenicol<br />Procedure<br />Allow bacteria to incubate<br />Measure zone of no growth<br />Compare to known values to find sensitivity/resistance<br />
  11. 11. Results (Antimicrobial Susceptibility)<br />Tetracyclin = 20 mm (S)<br />Penicillin = 16 mm (R)<br />Streptomycin = 14 mm (I)<br />Vancomycin = NA (R)<br />Gentamicin = 14 mm (I)<br />Chloramphenicol= 22 (S)<br />What do these results mean?<br />Patient sample is:<br />Resistant to penicillin, vancomycin<br />Intermediate to streptomycin, gentamicin<br />Sensitive to tetracyclin, chloramphenicol<br />Eliminate P. aeuroginosa<br />Resistant to chloramphenicol<br />Eliminate H. influenzae<br />Different symptoms (meningitis)<br />
  12. 12. Salmonella enterica<br />A rod shaped, flagellated, Gram negative bacteria<br />
  13. 13. Salmonella enterica<br />Arranged in a cluster- tetrad form<br />Anaerobic- can live with low oxygen conditions<br />Affects gastrointestinal region, through the fecal oral route<br />Injects a protein called SipA to enter cell<br />Disturbs the membrane, causes levels of free calcium to rise and disorganizes cytoplasm<br />
  14. 14. Epidemiology<br />Causes diarrhea, fever, vomiting, abdominal cramps<br />Can spread from intestine to blood stream, cause bacteremia<br />raw meat, eggs (can be found on any food surface)<br />Normal bacterial flora in reptiles and amphibians<br />contaminated water or soil<br />Salmonellosis can be prevented by<br />Cooking food thoroughly<br />Washing hands and cooking surfaces<br />refrigeration<br />Single most common cause of food poisoning in the US<br />Salmonellosis<br />

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