Presence: The microorganism must be found in abundance in all suffering organisms but not in healthy ones. Isolation: The microorganism must be isolated from a diseased organism and grown in a pure culture. Inoculation: The cultured microorganism should cause disease when introduced into a healthy organism. Re-isolation: The microorganism must be re-isolated from the experimental host and identified as identical to the original agent

Does not account for asymptomatic hosts. Not all organisms can be grown in pure culture (e.g., viruses). Does not account for mutations.

Water is easily contaminated, and E. coli is used as an indicator organism for fecal contamination

It is a coliform: it ferments lactose into acid and gas. It is the most common enteric, easy to grow/identify, and lives long in water. Its presence suggests other pathogens may be present.

Removal of Solid Waste (coagulation) Sedimentation Filtration: Non-potable water stops here. Disinfection: Required for potable (drinking) water.

Presumptive: Inoculate lactose broth with varying water volumes (10mL,1mL,.1mL). Determines relative abundance of coliforms based on gas production.

Confirmation Streak positive (gassing) broth onto EMB agar. Rules out non-coliforms (like Clostridium) that also ferment lactose.

Completed Inoculate Brilliant Green Bile Broth and a Nutrient Agar streak. Identifies if the isolated colonies can

Final Gram stain colonies from the positive Brilliant Green Bile broth. Final confirmation of Gram-negative coliforms.

A pH indicator used in the presumptive test; it turns yellow when acid is produced from lactose fermentation.

Selective for Gram-negative bacteria; identifies lactose fermentation through color changes.

Brillant Greene Bile Broth

A highly selective medium used to confirm that the bacteria can survive the harsh environment of the intestinal tract (bile).

dental test yellow-more acid production and more dental problems green - less acid production and less problems

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micr lab week 13

Question	Answer
KOCHS POSTULATES	Presence: The microorganism must be found in abundance in all suffering organisms but not in healthy ones. Isolation: The microorganism must be isolated from a diseased organism and grown in a pure culture. Inoculation: The cultured microorganism should cause disease when introduced into a healthy organism. Re-isolation: The microorganism must be re-isolated from the experimental host and identified as identical to the original agent
Kochs limitations	Does not account for asymptomatic hosts. Not all organisms can be grown in pure culture (e.g., viruses). Does not account for mutations.
Water contamination	Water is easily contaminated, and E. coli is used as an indicator organism for fecal contamination
Why e. coli?	It is a coliform: it ferments lactose into acid and gas. It is the most common enteric, easy to grow/identify, and lives long in water. Its presence suggests other pathogens may be present.
water treatment	Removal of Solid Waste (coagulation) Sedimentation Filtration: Non-potable water stops here. Disinfection: Required for potable (drinking) water.
Day 1	Presumptive: Inoculate lactose broth with varying water volumes (10mL,1mL,.1mL). Determines relative abundance of coliforms based on gas production.
Day 2	Confirmation Streak positive (gassing) broth onto EMB agar. Rules out non-coliforms (like Clostridium) that also ferment lactose.
Day 3	Completed Inoculate Brilliant Green Bile Broth and a Nutrient Agar streak. Identifies if the isolated colonies can
Day 4	Final Gram stain colonies from the positive Brilliant Green Bile broth. Final confirmation of Gram-negative coliforms.
Bromothymol Blue	A pH indicator used in the presumptive test; it turns yellow when acid is produced from lactose fermentation.
EMB	Selective for Gram-negative bacteria; identifies lactose fermentation through color changes.
Brillant Greene Bile Broth	A highly selective medium used to confirm that the bacteria can survive the harsh environment of the intestinal tract (bile).
Snyders test	dental test yellow-more acid production and more dental problems green - less acid production and less problems

Created by: agk236

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