1. Draw and describe the possible result that may be observed on an agar plate that utilized a 4- streak quadrant method for isolation WITHOUT the conduct of proper aseptic techniques Source of inoculum: Tap water Characteristic of colony: Yellow, circular colony with entire margin and convex elevation Answer: 2. Using your fingers, you are asked to aseptically touch the surface of a sterile agar plate. Illustrate the possible result from this step if your fingers are (a) unwashed – touched various things prior to placing on agar surface, and (b) washed with soap or disinfected with 70% alcohol. Describe the relative abundance of microbial growth observed on the plates. Unwashed Washed Answer. 3. List and draw the possible characteristics of an isolated bacterial colony that can be observed based on type of (a) margin, (b) elevation, (C) texture, and (d) optical property.

1. Draw and describe the possible result that may be observed on an agar plate that utilized a 4- streak quadrant method for isolation WITHOUT the conduct of proper aseptic techniques Source of inoculum: Tap water Characteristic of colony: Yellow, circular colony with entire margin and convex elevation Answer: 2. Using your fingers, you are asked to aseptically touch the surface of a sterile agar plate. Illustrate the possible result from this step if your fingers are (a) unwashed – touched various things prior to placing on agar surface, and (b) washed with soap or disinfected with 70% alcohol. Describe the relative abundance of microbial growth observed on the plates. Unwashed Washed Answer. 3. List and draw the possible characteristics of an isolated bacterial colony that can be observed based on type of (a) margin, (b) elevation, (C) texture, and (d) optical property.

Microbiology for Surgical Technologists (MindTap Course List)

2nd Edition

ISBN:9781111306663

Author:Margaret Rodriguez, Paul Price

Publisher:Margaret Rodriguez, Paul Price

Chapter4: The Prokaryotes

Section: Chapter Questions

Problem 5UTM

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1. Draw and describe the possible result that may be observed on an agar plate that utilized a 4-streak quadrant method for isolation WITHOUT the conduct of proper aseptic techniques Source of inoculum: Tap water Characteristic of colony: Yellow, circular colony with entire margin and convex elevation Answer: 2. Using your fingers, you are asked to aseptically touch the surface of a sterile agar plate. Illustrate the possible result from this step if your fingers are (a) unwashed – touched various things prior to placing on agar surface, and (b) washed with soap or disinfected with 70% alcohol. Describe the relative abundance of microbial growth observed on the plates. Unwashed Washed
answer the following questions with book reference. 1. What is meant by a bacterial “colony” or colony-forming unit? 2. Why are colonies that develop on a heavily seeded plate smaller than those that appear on a sparely seeded plate? 3. What are some of the uses and advantages of the ff.:a. Agar plateb. Agar slantc. Broth culture 4. What are the advantages and limitations of studying bacteria by means of the Culture method? 5. Why is it desirable that most cultures be inspected after 15 to 18 hours of incubation? 6. Why should culture media after inoculation be incubated at an optimal temperature immediately? 7. Describe other types of aerobic jars and anaerobic methods.
Human error is a factor in the Kirby-Bauer procedure that often contributes to variation in zone size. Circle the effect on the zone size if the following occurred: ● ● Overinoculating the agar with bacteria: Waiting too long to place disks after inoculation: Using a culture that is less than 0.5 MacFarland: False increase False increase False increase False decrease False decrease False decrease
1. Describe the three different type of hemolysis that are observed on blood agar.2. What is a selective medium?3. What is a differential medium?4. Which media can be used to isolate E. coli samples from contaminated lettuce?5. Which two media would be used to identify a sample taken from a patient with suspected gonorrhea?6. Would you be able to grow a sample obtained from a patient's wound (suspected to be infected with MRSA) on EMB? Explain.7. What is the color or TSI for Salmonella?8. What is a fastidious organism?
Determine what percentage of the culture was living (viable) and what percentage was dead (mortality). Plates Plate Dilution Volume plated No.of colonies Avg No Concentration of diluted sample Cd(cells/mL) Concentration of original sample Cu(cells/mL) 1 10^-3 10ul R1=130,R2= 110,R3=210 150 150mL 1.50*10^6 Volume of cells(mL) Volume of diluent(mL) Total dilution(D) Hemocytometer count Avg cells in 1 mm^2 area Concentration of diluted sample Cd(cells/mL) Concentration of original sample Cu(cells/mL) 4.3 0.5 0.1 grid 1= 171 , grid2 = 185 178 1.78*10^5 1.78*10^6
A. Microscopic Observation of Cells Wet Mounts, Gram stain and spore stain 1 Describe the microscopic morphology and behavior of each species observed with a wet mount (A. serpens and E. gracilis). 2 Describe the microscopic morphology of each sample observed with a Gram stain (S. aureus, P. aeruginosa, B. subtilis and dental plaque). Indicate the Gram reaction of each. 3Describe the microscopic morphology of each sample observed with the spore stain (P. aeruginosa and B. subtilis). In which of the sample can you see spores?
Diagram illustrating Miles & Misra technique for determining viable counts: 10ul 10-5 106 104 10-7 3. Set up controls of the donor and recipient cultures as follows: • Spread plate 0.1 ml of the donor culture over the surface of each of the 3 different selective media (i.e. nutrient agar + Ap; nutrient agar + Sm; nutrient agar + Rif) • Similarly spread plate 0.1 ml of the recipient culture over the surface of each of the 3 selective media • What is the purpose of this step?
a. Explain whether or not any of the methods in fi gure 2.9 could beused to determine the total number of cells present in a patient’s specimen.b. After performing the streak plate method on a bacterial specimen, theculture was incubated for 48 hours at 37°C. Upon viewing the plate, therewas heavy growth (with no isolated colonies) in the fi rst quadrant, but nogrowth was apparent in the remaining quadrants. Please discuss errors in the procedure that could have produced this result.
A surgical technologist working in the Central Sterile Processing Department is asked to run the steam sterilizer (autoclave) with a biological monitor for the first load of the day without any instrument trays or items. What must be done with the bacterial sample after it is processed in the sterilizer?
On Aseptic Techniques: What is/are the instances/situations that each method of inoculation is to be used?
1. how does colony appearance and location with respect to the agar differ on the spread and pour plate? 2. list two additional factors that contribute to error in the spread plate method:
Assuming that serial dilution was carried out in a laboratory experiment in 6 tubes with 9 ml of saline in each tube and 0.1ml of the stock solution was used for initial dilution, pour plate method of inoculation was performed after the dilution process using 1ml of the culture from the samples from the test tubes. It was found out that on the 6th Petri dish after incubation, there was a total of 16 individual colonies counted. Compute the total number of microorganisms present in tube one, assuming that there was no human error in the transferring proces.