pooper boy 2

Coliforms are members of what family?

Enterobacteriaceae

True/False: Coliforms do NOT ferment lactose

FALSE

Non-coliform enterics do NOT ferment lactose but are still part of the enteric flora

Which of the following are characteristics of coliforms?

I- Gram negative

II- Non-spore forming rods

III- lactose fermenting (w/ acid and gas production)

IV - part of normal enteric flora

V- found in the environment

VI- found in feces of warm flood animals

All

The following bacteria are examples of what?

Enterobacter, Klebsiella, Citrobacter, Escherichia

Coliforms

What is the difference between coliforms and non-coliform enterics?

Coliforms are lactose fermenting while non-coliform enterics do NOT ferment lactose

Both are still part of enteric flora

What is used as a bacterial indicator of the sanitary quality of food and water?

Coliforms

What are two reasons why coliforms are used as water quality indicators?

1. Coliforms are associated with sources of pathogens

2. Analysis for coliforms is simple, economical and efficient

What method do we use to measure the total number of coliforms present in a sample?

Multiple Tube Fermentation Method

What three groups of microorganisms are found in soil?

Bacteria, Actinomycetes, and Fungi

Glycerol Yeast Extract Agar (GYEA) isolates what group of microorganisms?

Actinomycetes due to the agar not having enough nutritive value for typical bacteria or fungi

Tryptic Soy Agar (TSA) isolates what group of microorganisms?

Broad range of bacteria but not fungi

Sabouraud Dextrose Agar (SDA) with addition of Ampicillin/Streptomycin isolates what group of microorganisms?

Fungi. Without the addition of Ampicillin/Streptomycin, the media would support the growth of bacteria

What describes ALL microbial agents, both natural and synthetic, used to treat bacterial infections?

Antimicrobials

What are natural antimicrobial agents produced by microorganisms

Antibiotics

Penicillin is produced by the mold _ and is an example of a(n)_.

Penicillium notatum; Antibiotic

Bactericidal:

A. Kills the microbe

B. Stops the growth but does not kill the microbe

A. Kills the microbe

Bacteriostatic:

A. Kills the microbe

B. Stops the growth but does not kill the microbe

B. Stops the growth but does not kill the microbe

What is the standard tool for measuring the effectiveness of antimicrobials against pathogenic microorganisms?

Kirby-Bauer test or disk diffusion test

The size of the "zone of inhibition" depends upon

Sensitivity of the bacteria to the specific microbial agent

If a clear zone appears around the disk, is the organism susceptible or resistant to the antimicrobial?

Susceptible

Brilliant Green Lactose Bile Broth (BGLB) is what type of medium?

Selective and differential

How does Brilliant Green Lactose Bile (BGLB) have selective media characteristics?

The broth contains bile and brilliant green dye which inhibit the growth of gram (+) organisms

How does Brilliant Green Lactose Bile (BGLB) have differential media characteristics?

The broth contains lactose as the main source for fermentation, only organisms that can ferment lactose will grow

What indicates a positive result after inoculation of Brilliant Green Lactose Bile (BGLB)?

Turbidity (cloudiness) in the broth and gas bubbles in the Durham tubes

What is the formula to calculate the original cell density (CFU/mL)?

of colonies / (volume plated * dilution)

What is the largest majority of microbes found in the soil?

Saprophytes

What microorganism can break down organic matter to enrich the soil?

Saprophytes

Which two microbes are responsible for about 2/3rds of the antibiotics used today?

Actinobacteria and fungi

What type of media is Tryptic Soy Agar (TSA)?

Non-selective

Where do fecal coliforms live?

The digestive tract of animals

What are the 4 bacteria that make up the total number of coliforms?

Enterobacter, Klebsiella, Citrobacter, or Escherichia

How can the number of total coliforms in a water sample be determined by statistical estimation?

Most probable number (MPN) test

Why are the number of total coliforms tested by multiple series of Durham fermentation tubes and not a plate count method?

Non-coliform microorganisms in the sample would interfere if a plate count method was used

What is the presumptive test?

One looks for bacteria capable of fermenting lactose with gas production. The MPN can also be estimated during this test

What is the confirmed test?

Positive tubes from the presumptive test are confirmed to contain coliforms through BGLB inoculation (selective and differential for coliforms)

What is the completed test?

Test if growth is present on an EMB or HE plate to further confirm the presence of coliforms

Which bacteria (gram negative/positive) have a harder time being killed by antibiotics?

Gram negative bacteria are harder to kill due to the presence of an outer membrane

What media and bacterial dilution is used to insure the diffusion of the antibiotic is standardized every laboratory use?

Mueller-Hinton Agar and 1x10^8 CFU/mL

Microbial growth at temperatures higher than 45 C

Thermophiles

Microbial growth that will not grow at temperatures less than 40 C

Obligate thermophiles

Microbial growth at temperatures below 40 C

Facultative thermophiles

Microbial growth at temperatures above 80 C

Extreme thermophiles

As hydrogen ions increase, the pH ___

Decreases

Microbial growth below pH 5.5

Acidophiles

Microbial growth between pH 5.5-8.5

Neutrophiles

Microbial growth above pH 8.5

Alkaliphiles

True/False: Regardless of their habitat, bacteria maintain a near-neutral internal environment

True

Describe the effects of culturing in vitro during fermentation and protein metabolism?

Fermentation: Acid is a byproduct which can destroy enzyme integrity

Metabolism: Alkaline is a byproduct which can destroy enzyme integrity

What is the difference between aerobic and anaerobic?

Aerobic: ability to live in the presence of oxygen

Anaerobic: inability to live in the presence of oxygen

Classify the organism: Requires oxygen for respiration

Obligate (strict) aerobe

Classify the organism: Grow in the presence or absence of oxygen

Facultative anaerobe

Classify the organism: small amounts of oxygen are lethal

Obligate (strict) anaerobe

Classify the organism: Doesn't require oxygen and are not adversely affected by it

Aerotolerant

Classify the organism: Survive only in environments containing lower than atmospheric levels of oxygen

Microaerophiles

We can use ___ to determine if an organism is aerobic or anaerobic by observing its growth patterns in the media

Thioglycolate

Thioglycolate broth is a ___ ___ media

Nonselective enriched

Identify the organism: Will grow at the top of the media where oxygen is most plentiful

Obligate (strict) aerobe

Identify the organism: Will grow throughout the medium but will appear denser at the top

Facultative anaerobe

Identify the organism: Will only grow in the lower regions of the medium

Obligate (strict) anaerobes

Identify the organism: Will grow uniformly throughout the medium

Aerotolerant

What is the indicator for the presence of oxygen in Anaerobic jars?

Methylene blue

What components make a gas pack in an Anerobic jar?

NaBH4 (Sodium borohydride), NaHCO3 (Sodium bicarbonate) and palladium (catalyst)

What type of media is Eosin Methylene Blue (EMB) agar?

Selective and differential

How is Eosin Methylene Blue (EMB) agar selective?

It inhibits the growth of gram positive bacteria

How is Eosin Methylene Blue (EMB) agar differential?

Lactose fermenters are colored colonies while non-lactose fermenters are colorless colonies

What type of media is Hektoen Enteric (HE) agar?

Selective and differential

How is Hektoen Enteric (HE) agar selective?

It inhibits the growth of gram positive bacteria

How is Hektoen Enteric (HE) agar differential?

Bacteria that ferment carbohydrates turn yellow and bacteria that undergo hydrogen sulfide reduction produce black precipitate

Formation of metallic green colonies on Eosin Methylene Blue (EMB) agar indicate?

E.coli (lactose fermenters)

Formation of brown centered colonies on Eosin Methylene Blue (EMB) agar indicate?

Enterobacter aerogenes

Formation of black colonies on Hektoen Enteric (HE) agar indicate?

Salmonella (hydrogen sulfide reduction)

Formation of green colonies on Hektoen Enteric (HE) agar indicate?

Shigella

Formation of yellow colonies on Hektoen Enteric (HE) agar indicate?

Fermentation of carbohydrates

What is the process by which competent bacterial cells pick up DNA from the environment and make use of the genes it carries?

Bacterial Transformation

What are closely linked genes that help regulate protein synthesis?

Operons

What is the name of the promoter on arabinose operon?

Pbad

What are the three structural genes in arabinose operon that code for enzymes used to digest arabinose?

araB, araA and araD

What is the binding protein that attaches to the promoter of arabinose operon and acts as an on/off switch?

araC

True/False: RNA polymerase can attach and transcribe genes on arabinose operon with and withOUT the presence of arabinose

FALSE. RNA polymerase can only attach to the promoter through the binding of arabinose to araC

What is added to media to keep the pH range neutral after production of acid and base products?

Buffers

What components make up Thioglycolate broth?

Yeast extract- for nutrients

Sodium thioglycolate- to lower the amount of oxygen in media

Resazurin- color indicator for oxygen that turns pink