Laboratory Experiments in Microbiology (11th Edition)
11th Edition
ISBN: 9780321994936
Author: Ted R. Johnson, Christine L. Case
Publisher: PEARSON
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Textbook Question
Chapter 26, Problem 1CA
The following data were collected from soaps after 1 week of use at a hospital nurses’ handwashing station. Neither bacteria nor
What conclusions can you draw from these data?
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The number of bacteria in saliva samples was determined by collecting the saliva, making serial dilutions, and inoculating nutrient agar by the pour plate method. The plates were inoculated aerobically for 48 hours at 37°C.
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The following data were obtained from pour plates used to test the effectiveness of a food preservative. Two samples of cottage cheese were inoculated with bacteria; the preservative was added to one sample. After incubation, samples of the cottage cheese (control) and samples treated with the preservative (experimental) were diluted and plated on nutrient agar. Calculate the number of bacteria. Was the preservative effective?
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You must write up your OWN dichotomous key for all the possible unknown organisms listed below. The first step of the key will be the Gram Stain and the second will be Gram negative. Subsequent steps will include biochemical tests only.
Solve the identity of an unknown bacterial specimen by creating a dichotomous key and using the staining, culturing and biochemical identification procedures .
Possible Organisms
Alcaligenes faecalis
Enterobacter aerogenes
Enterococcus faecalis
Escherichia coli
Proteus vulgaris
Pseudomonas aeruginosa
Salmonella arizoniae
Staphylococcus aureus
Staphylococcus epidermidis
Staphylococcus saprophyticus
Streptococcusbovis
Streptococcus pyogenes.
Can you please help me find the dichotomous key .
Thank you !
Chapter 26 Solutions
Laboratory Experiments in Microbiology (11th Edition)
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- Why is a Bunsen burner used in the microbiology lab? (select all that apply) The flame is used to sterilize the inoculating loop. The flame kills microorganisms that float in the air and could contminate samples. To sterilize the lid of the agar plate. To reduce the spread of antibiotic resistance.arrow_forwardYou must find up your OWN dichotomous key for all the possible unknown organisms listed below. The first step of the key will be the Gram Stain. Subsequent steps will include biochemical tests only. Solve the identity of an unknown bacterial specimen by creating a dichotomous key and using the staining, culturing and biochemical identification procedures . Possible Organisms Alcaligenes faecalis Enterobacter aerogenes Enterococcus faecalis Escherichia coli Proteus vulgaris Pseudomonas aeruginosa Salmonella arizoniae Staphylococcus aureus Staphylococcus epidermidis Staphylococcus saprophyticus Streptococcusbovis Streptococcus pyogenes Note : The test must be performed using any of this test Mannitol Salt Agar, DNAse test, Catalase test, coagulase test, Novobiocin Test, BILE ESCULIN AGAR (BEA) TEST, Oxidase test, Bacitracin Sensitivity, Blood Agar . Macconkey, Nitrate Reduction test. Thank you so much in Advance !arrow_forwardFor the following agar media used, list their significant components and explain how they react. Provide one example of a bacterium that will show change to the components (positive), and one example of a bacterium that will not show change or grow on the medium (negative).arrow_forward
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- In a bacterial culture on an agar plate, what is a zone of inhibition? An area where the growth of bacteria is increased compared to the rest of the agar plate An area where the growth of bacteria is prevented or reduced compared to the rest of the agar plate An area where the growth of bacteria is not affected compared to the rest of the agar plate An area where the the agar becomes contaminated with moldarrow_forwardBacteria are not used as probiotic agents. O True O False The growth of bacteria that form endospores can be controlled by boiling. O True False Submit Backarrow_forwardYou must write up your OWN dichotomous key for all the possible unknown organisms listed below . The first step of the key will be the Gram Stain. Subsequent steps will include biochemical tests only. Solve the identity of an unknown bacterial specimen by creating a dichotomous key and using the staining, culturing and biochemical identification procedures . Possible Organisms Alcaligenes faecalis Enterobacter aerogenes Enterococcus faecalis Escherichia coli Proteus vulgaris Pseudomonas aeruginosa Salmonella arizoniae Staphylococcus aureus Staphylococcus epidermidis Staphylococcus saprophyticus Streptococcusbovis Streptococcus pyogenes Imp Note - the test should be performed using any of the following tests stated below. Bile Escalin test, Oxidaze test, Blood Agar , Catalese Test, Mannitol salt agar . Thank you !arrow_forward
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