If 5% w/v concentration of a bactericide of dilution coefficient of 3 takes 25 minutes to effect killing, what will be the time of kill when it is diluted 8 times A sanitizer with dilution coefficient of 0.5 takes 3 minutes to effect killing. If it takes 18 minutes to kill when it is diluted 5times, what is the initial concentration? An unknown concentration of ‘LD’ disinfectant killed 106 viable cells of Sporotrichum schenkii within a certain time. When the concentration was increased 2-fold the extinction time decreased a 103-fold. Determine the concentration exponent of this disinfectant

If 5% w/v concentration of a bactericide of dilution coefficient of 3 takes 25 minutes to effect killing, what will be the time of kill when it is diluted 8 times A sanitizer with dilution coefficient of 0.5 takes 3 minutes to effect killing. If it takes 18 minutes to kill when it is diluted 5times, what is the initial concentration? An unknown concentration of ‘LD’ disinfectant killed 106 viable cells of Sporotrichum schenkii within a certain time. When the concentration was increased 2-fold the extinction time decreased a 103-fold. Determine the concentration exponent of this disinfectant

Body Structures & Functions Updated

13th Edition

ISBN:9780357191606

Author:Scott

Publisher:Scott

Chapter16: Infection Control And Standard Precautions

Section: Chapter Questions

Problem 10FITB

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of 1 stion s page 30- F2 Which of the following terms is associated with the probability of a preparation not being sterile after it has been exposed to a sterilization process? Select one: Oa. Particulate Matter level Qb. Sterility Assurance level О с. Pyrogen Load level O d. Optimal Sterilization level F3 F4 F5 Ol پیار Q Search F6 F7 F8 F9 === 8 9 F10 Time left 22:34:03 F11 Next page
Special Media for Isolating Bacteria OBJECTIVES Because multiple methods and multiple media exist, you must be able to match the correct procedure to the desired microbe. For example, if bacterium B is salt-tolerant, a high concentration (>5%) of salt could be added to the culture medium. Physical conditions can also be used to select for a bacterium. If bacteri- After completing this exercise, you should be able to: 1. Differentiate selective from differential media. 2. Provide an application for enrichment and selec- tive media. um B is heat-resistant, the specimen could be heated before isolation. Dyes such as phenol red, eosin, or methylene blue are sometimes ineluded in differential BACKGROUND media. Products of bacterial metabolism can react with One of the major limitations of dilution techniques used to isolate bacteria is that organisms present in limited amounts may be diluted out on plates filled with dominant bacteria. For example, if the culture to be isolated has 1…
This is how a hanging-drop slide is prepared. Figure from Macedo, Wikimedia Commons, 2016. 2 3 4 slide cover slip vaseline concavity drop of microbiological culture CA inoculation loop 11. Which slide gives you more information, the hanging drop or the stained slide? Why do you say so? 12. Why might it be valuable to know whether a bacterium is motile?
Examine the given sets of table below. Which disinfectant is the MOST recommended? Support and Justify your answer. Table 2. Phenol Coefficient of Test Disinfectant Name of disinfectant Growth after 5 minutes Dettol Phenol Name of disinfectant Z-germicSide Phenol Name of disinfectant Jik Phenol KEY:- = No growth, + = Growth Dilution 1:100 1:125 1:150 1:175 1:200 1:95 1:100 1:105 1:110 1:115 Dilution 1:100 1:125 1:150 1:175 1:200 1:95 1:100 1:105 1:110 1:115 Dilution 1:100 1:125 1:150 1:175 1:200 1:95 1:100 1:105 1:110 1:115 + + + + + + + + Growth after 5 mins + + + + + + + Growth after 5 mins + + + + + + Growth after 10 minutes + + + + + Growth after 10 minutes + + + + + Growth after 10 mins + - + + + + + + Growth after 15 minutes + + + + + + Growth after 15 mins - + + + + + Growth after 15 mins + + + + - + + + +
1 ml from main culture 5 ml LB 1 ml 1ml 1ml 5 ml LB I ? 5ml LB 1 ml 5 ml LB 5 ml LB You took 250 µl of the last dilution and planted it on solid medium. 50 colonies were counted A total of 10 ml of microbial culture (liquid LB+ e.coli) was brought to your laboratory in a container. This sample contains the bacteria Escherichia coli. The person who brought in wants to know how many colonies (cfu) there are in the culture. You have started the experiment by taking 1 ml from the culture and then added into the first tube which contain 5 ml of LB. After that, you diluted the sample with a dilution rate of 1/6 with 4 times (take 1 ml in 5 ml of LB medium (so total 6 ml)). You took 250 μl of the last dilution and planted it on solid medium and when counted after incubation, 50 colonies were counted. How many cfu/ ml bacteria are there in the sample (main stock) in total? (please show all your calculations and steps). Attach File
When a disinfectant or antiseptic's effectiveness is expressed as a phenol coefficient, a number ____ 1.0 means the chemical agent is more effective than phenol. less than greater than equal to
Why 10% bleach disinfectant are most against probiotic?
What appropriate method should be used in controlling microbial growth in each of the following? 1. Chicken serum 2. Fresh goat milk 3. Nutrient broth 4. Paracetamol 5. Inoculation loob
1 H 2 176 old culture Smear too BOTERC Losk like? + b. Failure to apply the decolorizer. + ne c. Failure to apply the safranin. Determine whether bacteria are motle or non-motle by looking at the growth in semi-solid medium What is the concentration of agar in (a) typical solid medium (b) semi sold motility medium? Arawer Q1 on Page 357. 7. Orygen Requirement: + d. Reversal of crystal violet and safranin stains. A questions 1.2 and 3 o Pg 83-84 Refer to the power point Questions 1 Predict the effect of the following "mistakes" made when performing a Gram stain. Your answer needs to address the predicted effect on both Gram-positive and Gram-negative cells. Consider each mistake independently. a. Failure to add the iodine. 414 gait to fer. 2 Both crystal violet and safranin are basic stains and may be used to do simple stains on Gram-positive and Gram-negative cells. This being the case, explain how they stain different cell types in the Gram stain. why? a cell wall. patem in…
A serial dilution of a bacterial culture yields the following number of colonies. Which plate(s) should be used to determine the original cell density? Plate A Plate B Plate C Plate D Plate E Dilution Factor 10-5 10-6 10-7 10-8 10-9 # of Colonies Too many to count 850 456 80 14 Group of answer choices All of these choices A & B D & E E None of these choices A B & C D B C & D C
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
Do you think UVC disinfection of N95 face masks is effective? Give two important considerations for UVC disinfection of N95 face masks to be effective?