Micro Lab Test 3 9 -12

Front 1

In the carbohydrate fermentation test what is the function of phenol red and the small inverted burham tube and what process does this indicate?

Back 1

Phenol red is a pH indicator that detects acid production while the durham tube detects gas production. both of these products acid and gas are due to fermentation of sugars in the media

Front 2

In the citrate utilization test what pH indicator is used to detect citrate use and what color does this indicator become in alkaline conditions a positive result?

Back 2

The pH indicator promot bromothymol blue turns from green to blue in an alkaline environment

Front 3

In the amino acid decarboxylase test what pH indicator is used to detect decarboxylase activity and what color does the indicator become in alkaline conditions a positive result?

Back 3

The pH indicator chrome cresol purple turns from yellow to purple in alkaline environment

Front 4

In the urea hydrolysis test what pH indicator is used to detect you urease activity and what color does it indicator become an alkaline conditions a positive result

Back 4

PH indicator phenol red turns from orange to bright pink in alkaline environment

Front 5

In the sim test what do the three letters represent S I M and how does each positive result appear

Back 5

Sulfide indole and motility.

Sulfide- hydrogen sulfide a by product resulting from the breakdown of cysteine combines with ferrous ions in the growth media to yield the black precipitate

Indole - by product resulting from the breakdown of tryptophan reacts with Kovacs reagent too yield red solution.

Motility - Motile bacteria will reproduce a diffuse cloud of growth extended from a stab in the semi soild agar.

Front 6

Antisepsis

Back 6

Inhibition or killing of microorganisms on the skin or living tissue by use of a chemical antiseptic

Front 7

Antiseptic

Back 7

Chemical used to inhibit or kill microorganisms on skin or living tissue

Front 8

Aseptic

Back 8

Characteristic of an environment or procedure that is free of pathogenic contaminants

Front 9

Aseptic technique

Back 9

Methods of handling microbial cultures patient specimens and other sources of microbes in a way that prevents infection of the handler and others who may be exposed

Front 10

Bacteriocidal

Back 10

A process or agent that kills bacteria

Front 11

Bactereostatic

Back 11

A process or agent that inhibits bacterial growth

Front 12

Degerming

Back 12

Removal of microbes by mechanical means

Front 13

Disinfectant

Back 13

Physical or chemical agent used to inhibit or destroy most microorganisms and viruses on in inanimate objects

Front 14

Disinfection

Back 14

The use of a physical or chemical agents to inhibit or destroy microorganism on inanimate objects

Front 15

sanitization

Back 15

The process of disinfecting surfaces and utensils used by the public

Front 16

Sterilization

Back 16

Any process that completely remove the destroyed all viable micro organisms including bacterial spores and viruses from an object or habitat

Front 17

Sterile

Back 17

Free of microbial contamination including bacterial spores and viruses

Front 18

How would you tell if the action of antibiotic is bactericidal or bacteriostatic?

Back 18

A sample from the zone inhibition can be inculcated into nutrient broth if bacteria grow in the broth the action of the antibiotic was bacteriostatic not bacteriocidal

Front 19

Why are Bacillus and clostridium species considered more potentially resistant to disinfectants and antiseptics septics

Back 19

Both species form highly resistant spores

Front 20

What is it about hydrogen peroxide that makes it effective in controlling the growth of vegetative anaerobes?

Back 20

Hydrogen peroxide breaks down to form water and oxygen . oxygen is toxic in anaerobes

Front 21

What would a chemical agent have to destroy in order to be called a sterilizer?

Back 21

Bacterial spores

Front 22

Why are biochemical lab tests so important to microbiologists?

Back 22

microscopic and macroscopic characteristics provide important identification criteria there can be many similarities and inconsistency between micro organism. by determining which enzymes are present unknown microorganism can be differentiated and identified through the presence or absence of specific biochemical reactions

Front 23

Coliform

Back 23

Gram-negative bacteria that ferment lactose to produce gas found in the intestinal tract of animals and humans

Front 24

Fermentation

Back 24

The extraction of energy through anaerobic degradation of substrates into simpler reduced metabolites

Front 25

Presumptive test

Back 25

A series of phenol red lactose broths are inculated with water samples. After incubation for 24 to 48 hours. If acid and gas are produced it is presumed that coliforms are present in the water sample

Front 26

Confirmed test

Back 26

Positive tubes from the highest delution of sample from the presumptive test are streaked onto eosin methanol blue EMB agar. the presence of coliform like colonies small metallic green colonies with dark centers confirms the presence of lactose fermenting gram-negative a bacterium

Front 27

Completed test

Back 27

Dark colonies from EMB with a green metallic sheen are transferred to a lactose broth tube and nutrient agar slant. If acid and gas are produced in the lactose broth to within 24 hours and a Gram stain to test a gram negative rod this is considered a positive completed test. The water is considered contaminated with coliforms and unsafe to drink

Front 28

Lactose

Back 28

Carbohydrate commonly found in milk

Front 29

Selective media

Back 29

Favors growth of specific microorganisms and inhibits growth of unwanted ones

Front 30

Differential media

Back 30

Distinguishes between groups of microorganisms is based on different chemical reactions and appearances

Front 31

MPN

Back 31

Abbreviation for most probable number this coliform test is used to detect the concentration of contaminants in water

Front 32

Which bacteria are considered the index of fecal contamination?

Back 32

Escherichia coli and enterobacter species

Front 33

What characteristic distinguishes coliforms from non coliforms?

Back 33

Coliforms ferment lactose to produce acid and gas within 48 hours while non coliforms do not ferment lactose

Front 34

Trypticase soy agar

Back 34

This medium contains just a basic elemental requirements. It is used for savings. Cultures as well as growing organisms for various testing procedures it is a general-purpose growth media

Front 35

Eosin methanol blue agar

Back 35

A selective and differential medium used to isolate fecal coliforms. Escherichia coli will most often produce dark colonies which have a green metallic sheen while other coliforms will produce a pink or purple colonies with a mucoid appearance

Front 36

Enterotoxin

Back 36

Chemical secreted by microorganisms that affect cells lining the intestinal tract

Front 37

How does refrigeration affect the microorganisms found in milk and food?

Back 37

Lower temperatures have bacteriostatic effects on many microorganisms. Refrigeration can slow down, but not necessarily inhibit, microbial growth

Front 38

If improperly treated canned foods are vacuum sealed, what kind of bacterium can survive to cause food poisoning

Back 38

Microorganisms that can grow under anaerobic conditions, such as chlostridium botulinum can grow and thrive under vacuum sealed conditions and releases toxins back was food poisoning

Front 39

Trypticase soy agar

Back 39

This medium contains just a basic element requirements. It is used for saving stock cultures as well as growing organisms for various testing procedures, it is a general-purpose growth medium

Front 40

Eosin methanol blue agar

Back 40

A selective and differential media used to isolate fecal coliforms

Front 41

Mannitol salt agar

Back 41

The addition of high amounts of salts make this medium highly selective for the halophiles preferring organisms such as genus Staphyloccus it is also differential for mannitol fermentation . halopiles that ferment mannitol will appear yellow for example Staphylococcus arias will ferment mannitol to producing yellow colonies surrounded by yellow zone, Wall Staphylococcus epidermidis will not ferment mannitol growing as white colonies with no yellow zones

Front 42

Phenylethyl alcohol agar

Back 42

Gram-negative organisms are partially inhabitated by the addition of alcohol, making the medium selected for the growth of gram-positive organisms. streptococcus species such as streptococcus enterococciI produce small, pinpoint, white colonies

Front 43

Salmonella - Shigella agar

Back 43

Used to isolate Salmonella and Shigella coliforms are inhibited. Species of the genus Salmonella will produced are colonies. Species of the genus shegella are inhibited or produced green or brown as colonies

Front 44

Hekteon enteric agar

Back 44

A selective and differential medium designed to isolate and differentiate species of Salmonella and Shigella from other Enterobacteriaceae. Bile salts and the dyes bromthymol blue and acid fuchsin inhibit the growth of most gram positive organisms. Salmonella and shingella species produced bluest / green colonies. Coliforms such as a Escherichia coli produced salmon too orange coloured colonies