MBIO 1220 Lecture Notes - Lecture 5: Disinfectant, Quaternary Ammonium Cation, Ultra-High-Temperature Processing

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brownsnake143

26 Nov 2018

School

University of Manitoba

Department

Microbiology

Course

MBIO 1220

Professor

Silvia Cardona

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Document Summary

The material contained in this unit will be directly relevant to you in your career as a nurse. In a hospital setting, it is very important to use appropriate methods to ensure that microorganisms are removed. Upon completion of this unit you should be able to: define common terms used to describe antimicrobial agents; describe the different methods used to destroy microorganisms; and describe the different treatments that are commonly used to destroy microorganisms. While the learning objectives are brief, there is a large amount of important information contained within this unit. Unit activities: read the following sections in chapter 5 of the textbook. The summaries and/or guidelines provided with the reading list will direct you to the examinable parts of each textbook section: section 5. 1: approaches to control. Define the following terms: sterilization", disinfection", antiseptics", sanitization", and. The decision as to which type of mechanism of microbial control is used should take into consideration the situation.

Related Questions

Answer the following question by determining whether you woulduse a PHYSICAL or CHEMICAL agent to control microbial growth andthen NAME and DESCRIBE which physical or chemical method would bepreferred out of the following:

DRY HEAT, MOIST HEAT,PASTEURIZATION, IONIZING RADIATION, NON-IONIZING RADIATION,FILTRATION, PHENOLICS, HALOGENS, ALCOHOLS, SURFACTANTS, HYDROGENPEROXIDE, HEAVY MEATALS, SOAPS, ALDEHYDES, PERACETIC ACID

( Answer can be used more thanonce)

1/ A liquid drug is heat sensitive

2/ You are camping and have run out of water. You come upon astream. You are not sure how clean the water is. What would besafest method of ensuring the water drinkable

3/ The site of incision before surgery must be free of microbesin order to decreased infection

4/ Your childreb are on a farm and petting the animals. What isthe appropiate way to remove microbes from their hands

5/ Removing mold growing on surfaces in the home

6/ You are inoculating broth tubes with different bacteria eachfrom different streak plates. How would you make sure inoculatingyourbroth with one type of bacteria

7/ Treatment used on milk products to lower microbial counts

8/ Solutions, lines and instrument used during surgery

9/ Prefered treatment usedon food & dairy equipment

10/ A patient has a deep wound that is contaminated withanaerobic microorganisms

11/ Killing microbes onthe surface of meat, fruits andvegetables

harlequinleopard627

. You are interested in continuing the work of Dr Mendes. What is one additional question that you might logically ask about this issue? Justify the question that you propose by logically describing why this is an important question to ask. Design and describe how to run an experiment to test the question you proposed. Be very specific. Make sure that the design is feasible (no growing plants on Jupiter). Include the following: Â· Independent and dependent variables Â· Control variables Â· Equipment and supplies needed Â· Outline the basic protocol to follow. Â· Describe WHY and HOW you will manipulate variables

here is the full question:

Do soil microorganisms protect against crop disease?

The rhizosphere, the soil layer surrounding plant roots, is a complex community in which archaea, bacteria, fungi, and plants interact with one another. After plants are attacked by fungal or bacterial pathogens, soil from the rhizosphere may protect plants from future attacks. Such protective soil is called disease-suppressive.

Researchers investigated whether microorganisms were responsible for the protective effects of disease-suppressive soils. Disease-suppressive soil was obtained from an agricultural field in the Netherlands in which sugar beet crops had previously been attacked by a fungal pathogen, Rhizoctonia solani. Other soil was collected from the margin of the field. The researchers predicted that soil from the margin would not offer protection against pathogens.

The researchers then planted and raised sugar beets in greenhouses, using 5 different soil treatments. Each soil treatment was applied to 4 pots, and each pot contained 8 plants. The pots were inoculated with Rhizoctonia solani and placed in greenhouses kept at 20Â°C with a 16-hour light: 8-hour dark cycle. After 20 days, researchers determined the percentage of infected sugar beet seedlings for each soil treatment. The results of the experiment are shown in the table.

Soil Treatment	Percentage of Seedlings with Fungal Disease
Disease-suppressive soil	3.0
Soil from margin of field	62
Soil from margin of field +10% disease-suppressive soil	39
Disease-suppressive soil heated to 50âC for 1 hour	31
Disease-suppressive soil heated to 80âC for 1 hour	70

(Data from R. Mendes, et al. Deciphering the rhizosphere for disease-suppressive bacteria, Science 332: 1097-1100 (2011)).

Review Questions for Chapter 5: Control of Microbial Growth

1. Consider the following statement: âThorough handwashing with soap and water is the most important step in stopping the spread of many infectious diseasesâ.

a. Explain this statement.

b. Following thorough handwashing with soap, are your hands sterile? Why or why not?

2. If pasteurization does not achieve sterilization, why is pasteurization used to treat food? Why not just heat the food instead?

3. Consider the use of salts and sugars to preserve food.

a. How do salts and sugars preserve foods?

b. Why are these considered physical rather than chemical methods of microbial control?

c. Name one food that is preserved with sugar and one preserved with salt.

d. How do you account for the occasional growth of Penicillium mold in jelly, which is 50% sucrose?

4. Consider dried fruit you can buy at the store (e.g., raisins, pineapples, figs, dates, etc.) Dried fruits date back thousands of years B.C.

a. Why is this such an effective method of preserving food? Suggest several possibilities.

b. Fruit is often dried by being placed outside in the open under the sun in conditions that are not exactly sanitized. Why is this practice generally very safe?

5. There is great concern over healthcare-associated infections.

a. Why are healthcare settings such a âgoodâ place to catch infectious diseases? List several reasons.

b. What are several effective approaches that healthcare settings can take to minimize the spread of infectious disease?

6. Flying on an airplane includes lots of individuals in close quarters for potentially long periods of time.

a. What technology do you think airplanes use to reduce the amount of microbes from the air?

b. Despite this control method, there have been a number of documented cases of individuals infected with tuberculosis infecting other passengers during a flight. Explain how you think this happened. Which patients are at highest risk for infection, and what does this tell you about the effectiveness of microbial control on an airplane?

7. The thermal death time for a suspension of Bacillus subtilis endospores is 20 minutes in dry heat and less than 10 minutes in an autoclave. Which type of heat is more effective? Why?

8. A large hospital washes burn patients in a stainless steel tub. After each patient, the tub is cleaned with a quat. It was noticed that 14 of 20 burn patients acquired Pseudomonas infections

after being bathed. Provide an explanation for this high rate of infection.

9. If youâre on a municipal water supply, the water coming out of your faucet is chlorinated at the water treatment plant.

a. Is the water coming out of your faucet sterile?

b. Does the water still contain chlorine?

c. What are advantages and disadvantages of chlorine compared with other approaches (e.g., UV treatment, treatment with ozone).

10. You are a member of Engineers Without Borders, and your local chapter has been asked by a rural village in Thailand to assist them with improving their water supply, which they suspect of making villagers sick. The village has piping infrastructure that delivers water through a series of pipes to each household. Upon your initial site assessment of the village, you and your team determine that the water has high turbidity (particulate material) as well as a high bacterial count.

a. Design a strategy for treating the water to make it safe to drink that still relies upon the distribution system. Note that you may make some reasonable assumptions about conditions in the village (e.g., availability of electricity if you wish).

b. Identify some possible limitations of your approach.

11. A low technology approach to treating water in rural locations is to fill clear plastic soda bottles with water and leave it out all day in the sun (e.g., up on a roof).

a. What two factors are most likely at work in controlling microbes in these conditions?

b. What impact does each factor have on the microbes? Be specific.

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MBIO 1220 Lecture Notes - Lecture 5: Disinfectant, Quaternary Ammonium Cation, Ultra-High-Temperature Processing

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