LOS TACOS Olabade and Urma
May 31, 2015
LOS TACOSOlabade and Urma
Debriefing 67 cases in NJ, NY, PA, DE, and SC
Bloody diarrhea and severe abdominal cramps
of 67, 51 hospitalized and 8 kidney failures (hemolytic-uremic syndrome)
November 20 - December 5
Peak in the last week of November
Had all eaten at a Taco Bell
Chopped yellow onions tested positive for a pathogen; DNA fingerprinting confirms onions were not source of the infection
Possible Culprits Escherichia coli
Pseudomonas aeruginosa
Salmonella enterica
Staphylococcus aureus
Streptococcus pyogenes
Haemophilus influenzae
Gram Stain E. coli = gram –
S. aureus = gram +
Sample = ?
Gram Stain
Gram Stain
Gram Stain
Gram Stain
Gram Stain
Gram Stain
Gram Stain
Gram Stain
Microscopic
S. aureus
E. coli
Sample
First Elimination Escherichia coli (Gram-) Rod Shaped
Pseudomonas aeruginosa (Gram-) Rod Shaped
Salmonella enterica (Gram-) Rod Shaped
Staphylococcus aureus (Gram+) Spherical
Streptococcus pyogenes (Gram+)Spherical
Haemophilus influenzae (Gram-) Rod Shaped
Selective/Differential Media
MacConkey Agar Salt bile is selective aspect
Lactic acid is differential aspect
Grows Gram- bacteria and stains for lactose fermentation
Lac+ CO2, acid, and alcohol agar will become a bright pink/red color when lactose is
fermented because the acid lowers the pH
Lac- cannot ferment the lactose colorless
Gram+ can’t ferment lactose because the bile salts do not allow for them to grow, therefore not allowing them to ferment the lactose
MacConkey Agar
Second Elimination Escherichia coli (Gram-) Rod Shaped (Lac +)
Pseudomonas aeruginosa (Gram-) Rod Shaped
(Lac-)
Salmonella enterica (Gram-) Rod Shaped (Lac-)
Haemophilus influenzae (Gram-) Rod Shaped
(Lac +)
Escherichia coli orHaemophilus influenzae?Escherichia coli
Can cause: Food poisoning
Diarrhea
Gastroenteritis
Urinary Tract Infection
Haemophilus influenzae
Can cause: Bacteremia
Pneumonia
Acute Bacterial Meningitis
Usually in kids
It’s… E. coli!! Gram –
Rod shaped
Generally aerobic
Most strains are opportunistic pathogens
Capsulated and Non-Capsulated
Cell Wall/Shape/Arrangement
Outer membrane of cell wall is lipopolysaccharide that functions as endotoxin can lead to inflammation, high fever, hypotension, capillary
damage, intravascular coagulation, tissue degradation, and irreversible shock
Some pili let bacterium adhere to epithelial cells of the mucous membranes
Some cell wall adhesions let bacterium make more intimate contact with the mucous membranes
Some strains secrete enterotoxins that cause the loss of sodium ions and water from the small intestines watery diarrhea
Some strains secrete a toxin that kills epithelial cells of the large intestines bloody diarrhea
Metabolism Facultative Anaerobe
Metabolizes glucose in both the presence and absence of oxygen
Location in Nature Lower intestine of warm-blooded organisms
Can be found in: Unpasteurized milk and apple cider
Ham, turkey, chicken, roast beef, sandwich meats
Raw vegetables, cheese
Contaminated water
Damaging Human Host
Can severely damage lining of intestines
Resulting in
Epidemiology Consumption of contaminated foods
Hand- mouth
Human-human
Antimicrobial Susceptibility Test
Antimicrobial Susceptibility Test
Antimicrobial Susceptibility Test
E. Coli (mm) Staph (mm)
Gentamycin 21 (S) 10 (R)
Penicillin 0 (R) 27 (R)
Vancomycin 0 (R) 12 (S)
Chloramphenicol 25 (S) 17 (I)
Streptomycin 13 (I) 12 (I)
Tetracycline 22 (S) 19 (S)
Tetracycline Generally used in fighting infections of
urinary tract and intestines
Protein Synthesis Inhibitor
Kills bacterial cells by inhibiting their translation
Binds to 30S ribosomal subunit Prevents tRNA from binding to ribosome
Conclusion Patients ingested raw or undercooked meat
with E. coli from Taco Bell
Caused an infection
Tetracycline is the best antibiotic to give them Will halt the protein synthesis in the E. coli