Lab Practical 2

In most labs, the effect of antibiotics on bacteria is determined by what test?

Describe the Kirby-Bauer method.

How can the results of the Kirby-Bauer method be used to help treat a bacterial infection?

Mueller-Hinton agar gives ___ results and does not inhibit ___.

Zones that represent areas where bacterial growth was inhibited are known as a ___ of ___.

How is a zone of inhibition measured?

What are the 4 steps in the antibiotic susceptibility test?

The genus ___ includes a broad grp of gram-pos, facultatively anaerobic cocci that form chains of varying length.

What are some common places where species of streptococci are located on human skin?

Why is it that streptococcus must be cultivated on a rich medium such as blood agar?

Streptococci are an important component of the microbiota of the ___ ___ ___.

Streptococci organisms may be cultivated on an enriched medium that contains blood & is incubated in an environment rich in ___ & low in ___.

Streptococci that destroy RBCs completely and form a clear zone around the colonies are known as ___-___ streptococci.

What is an example of a Beta Hemolytic streptococci we encountered?

Streptococci that cause incomplete destruction of blood cells and their colonies are surrounded by an olive green or brown discoloration of the medium are ___-___ streptococci

Two examples of Alpha-hemolytic streptococci that we discussed are what?

Nonhemolytic streptococci cause no ___ of RBCs.  ___ that organism in yogurt is a member of this grp.

A 5% blood agar medium can be prepared with what 2 components?

S. mitis (___-hemolytic) and S. salivarius (___-hemolytic) are dominant species in the microbiota of the ___ ___.

S.mitis and S. salivarius in the oral cavity are found where?

What nonhemolytic species of streptococci ferments sucrose to acid and is an important cause of tooth decay?

A selective medium that contains crystal violet, potassium tellurite and trypan blue, which inhibit most gram-neg bacilli and gram-pos bacteria other than streptococci is known as ___ ___ agar.

___ ___ broth is an enriched medium containing glucose buffers, sodium carbonate & disodium phosphate which favor growth of hemolytic streptococci.

When Streptococcus mitis grows on a mitis salavarius plate the streptococcal colonies look how?

When Streptococcus salivarius grows on a mitis salavarius plate the streptococcal colonies look how?

Mitis salivarius agar inhibits the growth of what bacterial growth? 

When growing streptococcal bacteria in Todd Hewitt broth what do are we looking for to indicate that growth has actually occurred?

A broth used primarily to enrich the growth of pathogenic (beta-hemolytic) streptococci is called what?

Streptococci grown in Todd Hewitt broth grown in what form and look like what when Gram stained.

Members of the genus ____ are Gram pos spherical organisms about 1 micrometer in diameter

Staphylococcus grow in what 3 forms?

What members of the genus Staphylococcus grow on agar media they appear how? 

Staphylococcus bacteria are ___ tolerant and can grow on ordinary bacteriological media or on which selective media?

Certain strains of ___ ___ cause food poisoning, toxic shock syndrome (TSS) or boils and carbuncles.

The species of Staphylococcus that is usually a saprobe of the skin and is rarely involved in human infection is known as ___ ___.

A species of staphylococcus, ___ ___, is an opportunistic species that may cause UTIs in women of child bearing years

An alcohol derivative of the hexose mannose is known as ____. 

___ ___ is a species of staphylococcus that ferments mannose while ___ ___ and ___ ___ do not.

Why would we want to grow bacteria on a differential media?

We used mannitol salt agar, a medium that is both ___ and ___.  The ___ concentration is high and the mannitol is available for ___ to ___.

The indicator ___ ___ is included in mannitol salt agar to detect acid production.

Phenol red will change from ___ to ___ in the presence of acid producing S. aureus.

After obtaining a swab, inoculating mannitol salt agar plates and incubating, what should be seen on the plate if Staphylococcus species are present?

S. aureus produces what type of colonies on mannitol salt agar?

Colonies grown on mannitol salt agar that are surrounded by a yellow halo contain bacteria that did what and probably contain what species?

What do Micrococcus luteus colonies look like on an agar plate?

S. aureus has the ability to produce ____, an enzyme that clots blood plasma and enhances its virulence by providing resistance to ___.

S. aureus produces ___ to digest DNA and is also sensitive to the antibiotic ___.

Some of the bacteria normally found inhabiting the animal or human intestinal tract are Gram neg nonspore-forming rods called ____ ___.
 

What family do enteric bacteria belong too?

Many enteric bacteria species are ___ anaerobic, and certain species cause human diseases such as what? 

How can enteric bacteria species be isolated?

What 2 agars did we use to isolate enteric bacteria?

___ agar is a differential medium containing bile salts to inhibit non-enteric bacteria.

MacConkey agar contains 2 dyes, ___ and ___, which are taken up by lactose fermenting bacteria.

Crystal violet inhibits the growth of what?

When grown on MacConkey agar, enteric bacteria form ___ colonies whereas nonlactose fermenters form ___ colonies

EMB agar is a ___ medium that does not support the growth of Gram-___ bacteria.

On MacConkey agar lactose fermenting bacteria will appear as ___ colonies.

Escherichia coli will usually be ___ ___ colonies while Enterobacter, Kliebsiella and other lactose fermenters will be ___ to ___ with a ___ texture when grown on MacConkey agar.  

On EMB agar, E. coli colonies appear how?

On EMB agar, Enterobacter aerogenes colonies appear how?

Non-lactose fermenters grown on EMB agar look how?

What is another valuable medium for differentiating enteric bacteria?

What is the name given to a growth medium that contains glucose, lactose and sucrose as well as the pH indicator phenol red?

If a bacteria ferments ONLY glucose what will happen in TSI agar?

In bacteria the ferments ONLY glucose grown on TSI agar, what causes the red to return to the slant over time?

If bacteria ferments lactose, sucrose or both, then what will happen on TSI agar?

What will happen on TSI agar if no carbohydrates are fermented?

Gas production from carbohydrates may be determined in TSI agar by noting the presence of what?

Why is it that hydrogen sulfide production can be tested with TSI agar?

Certain bacteria use thiosulfate in their metabolism and release hydrogen sulfide which reacts w/iron yielding iron sulfide which appears how in TSI agar?

What is the primary purpose of the IMViC test?

What are the 4 tests that make up an IMViC series?

The ___ test IDs species that can digest tryptophan to ___ and other products.

The ___ ___ test depends on an organism's ability to ferment glucose and produce acid.

Methyl red indicator, added at the end of an incubation period remains ___ in acid solution but becomes ___ in alkaline or neutral solution.

The ___-___ test uses the digestion of glucose to acetylmethylcarbinol to differentiate between enteric species.

If acetylmethylcarbinol fr the digestion of glucose is present it will react w/alpha napthol & potassium hydroxide to form what?

The ___ test is based on the ability of certain bacteria to use ___, a salt citric acid, as a sole carbon source in growth.

What is the pH indicator in a citrate test?

What happens to pH when a bacteria uses citrate as a sole carbon source in growth?

What happens to bromthymol blue when pH rises?  What happens when pH doesn't change?

What agar is used for the citrate test?

What reagent is used for the indole test?

When doing an indole test what indicates a positive result?

What reagent is used when doing a methyl red test?

Explain the results of the methyl red test.

What are the 2 reagents used for the Vogues-Proskauer test?

What indicates a positive Vogues-Proskauer test?

A ___ color indicates an ability of a bacteria to to use citrate and constitutes a pos test.

What is seen on Simmons citrate agar that indicates a negative for citrate result?

Describe an Enterotube.

What are the 15 tests done utilizing an Enterotube?

What is Bacillus subtilis is used as a source of enzymes in ___.

The agent of anthrax is ___ ___.

The organisms of the Bacillus species are gram-___, sporeforming ___ that produce catalase, are motile and digest ___ & ___.

We isolated Bacillus species from where?

Why did we heat the soil samples prior to taking samples?

What reagent do we use to test for catalase production?

What do we add to colonies in order to test for starch digestion?

What should we observe around a colony if starch has been digested?

What are 4 important human diseases caused by Clostridium?

What do species of Clostridium do in soil?

Clostridium are Gram-___, sporeforming ___that grow under ___ conditions.

Name several places where anaerobic conditions exist and Clostridium can be found.

Thioglycolate medium contains ___ thioglycolate, a reducing agent the removes ____ from the environment.

Describe stormy fermentation.

What does Clostridium do when placed in cooked meat medium?

What is an advantage to using the pour plate technique with brain heart infusion agar?

SPS agar contains ___ ___ which is reduced by certain Clostridia to form sulfide

SPS agar contains ___ & ___ two antimicrobial agents that inhibit organisms other than Clostridium.

Blood in blood agar is ___ by clostridia to form the characteristic ___ zone of ___.

Explain the double zone of hemolysis created by clostridia on blood agar.

What should be observed in a thioglycolate medium inoculated with Clostridium species?

A Gram stain of a Clostridium species should reveal what?

What are 3 eukaryotic organisms in the microbial world?

____ grow as long, tangled filaments of cells.

Each filament of a mold is known as a ___.

A mass of mold filaments is called a ___.

Spores eventually form on the specialized hypha that form reproductive structures called ___ ___.

____ are unicellular microorganisms whose colonies on agar resemble bacterial colonies.

What do yeast colonies look like when grown on agar?

What is the primary mode of reproduction in yeasts?

Explain the process of budding.

___ ___ agar contains acidity & added carbohydrate favored by molds.

Broad spectrum antibiotics

Narrow spectrum antibiotics