Lab 16 Normal Flora and Hand Washing Exercise

Objectives

1.      Evaluate the advantages of normal flora.

2.      Identify body locations associated with normal flora and those locations that should be sterile.

3.      Describe the factors involved in effective hand washing.

4.      Differentiate between residential and transient bacteria.

5.      Chart and interpret the data from the handwashing experiment.

6.      Analyze factors affecting hand washing with regards to residential and transient bacteria.

7.      Integrate information from the hand washing experiment and the importance of normal flora with patient care.

Normal Flora

Symbiotic relationships with our normal flora are vital to our health, the bacteria receive benefits from the ecosystem our body represents for them (moisture, food, warmth) and we often receive either direct (production of folic acid by E.coli in our gut or indirect benefits (microbial competition and inhibition of pathogens).

Hand Washing

The transmission of organisms as a result of hand contact is well documented. State regulations mandate signs directing handwashing in all public restrooms. Food & Health care workers must be exceedingly careful to prevent inadvertently transferring pathogenic bacteria from infectious materials or people to others. 

Many microorganisms belong to the normal flora of our skin and represent no threat to a healthy individual; these are called resident flora. Residential flora can cause serious infections in immunocompromised patients. Inadvertent inoculation of skin organisms into susceptible areas (such as those introduced into the bladder with a urinary catheter or the blood with an I.V. catheter) may represent life threatening conditions. Organisms that are present for a short period of time, as a result of contact, are termed transient flora. These organisms, if pathogenic in nature, represent a real threat if introduced into a patient treatment. Removal of these organisms requires dedicated handwashing techniques. Transient flora tends to be more susceptible to antiseptic washes and easily removed with thorough scrubbing. Residential flora is more difficult to detach. A layer of oil, hair, and dead skin obstruct removal of these organisms. They are usually more resistant to soaps and antiseptics, but generally less pathogenic.

Hospital procedures require personnel to wash their hands before and after patient contact and with each glove change. Follow the protocol below and determine the effectiveness of handwashing with regards to

                  scrub time

                  soap type

                  use of antiseptics

                  transient flora versus resident organisms

                  water temperature

 Materials:

3 Nutrient Agar Plates per group

gloves

Soap (liquid)

Antiseptic - prepared fresh for each lab

Culture of E. coli or yeast for simulation

Sterilized Scrub brushes wrapped in foil (one per person)


 

Read the lab. Then write a hypothesis, a prediction, about the outcome of this experiment.

Hypothesis

 

Methods:

Lab partner # 1

 

1. Each person in the group will inoculate one plate. The plates are divided into 4 sections and are called quad plates. Notice that the quadrants are numbered I, II, III, IV. You may want to number them with the sharpie so the sections are more easily visible.

2. The first person in the group will label a plate "No Soap" and will touch area #1 with 3 fingers and the fingertips before washing. This represents a control.

3. Person number one continues as a partner aseptically unwraps a scrub brush and turns on the water. Without using soap scrub your hands for 15 seconds. Shake off excess water, allowing your hands to drip dry. While they are still damp, inoculate section #2 as above with the same three fingers and finger tips.

4. Continue by vigorously scrubbing with scrub brush & water only for an additional 15 seconds on fingers, palm, and back of hand and inoculate section #3 as above.

5. Finally dip your hands in the antiseptic wash; shake off excess water and antiseptic. Allow your hands to drip dry and while still damp inoculate section #4 as above.

Lab partner # 2

6.         The second person will label a plate " liquid soap" and then touch area #1 with 3 fingers and the fingertips before washing. This represents a control.

7.         Person number two continues as a partner aseptically unwraps a scrub brush, turns on the water, and helps to apply liquid soap onto their hands.  Scrub with the brush for 15 seconds. Rinse and shake off excess water, allowing your hands to drip dry. While still damp inoculate section #2 as above with the same three fingers and finger tips.

8.         Continue by vigorously scrubbing with liquid soap, brush & water for an additional 15 seconds. Inoculate section #3 as above.

9.         Finally rinse with the antiseptic wash, shake off excess water and antiseptic. Allow your hands to drip dry & while still damp inoculate section #4.

Lab Partner # 3

 10.       The third person will label a plate "transient bacteria". The instructor will apply bacteria or yeast to your hand as a simulation of transient flora contact.

 

11.       Person number three will then touch area #1 with 3 fingers and the fingertips before washing. This represents a control.

 12.       Person number three continues as a partner aseptically unwraps a scrub brush, turns on the water, and helps to apply liquid soap onto their hands.  Scrub with the brush for 15 seconds. Rinse and shake off excess water, allowing your hands to drip dry. While still damp inoculate section #2 as above with the same three fingers and finger tips.

13.       Continue by vigorously scrubbing with liquid soap & water for an additional 15 seconds and inoculate section #3 as above.

 14.       Finally dip your hands in antiseptic wash, shake off excess water and antiseptic. Allow your hands to drip dry & while still damp inoculate section #4.

 15.             Place all four labeled plates in the 36C incubator for 24 hours.

 Alternate lab partner #3 can use just the waterless hand cleaner like Purell

 Lab Session #2

 Read the plates and count the colonies. Record the data on the table.

 The unwashed hand serves as a control between the four individuals.

 Record the relative growth using:

 (0) = No growth    (+) = Very little growth (5 colonies or less)    (2+)= moderate growth (6-20 colonies)    (3+) for heavy growth (20 - 50 colonies)

 (4+) for confluent growth; uncountable

_______________________________________________________________________________________ 

Lab 16 Normal Flora and Hand Washing Exercise   Name______________

 

1.      How and when do humans get normal flora?

 

 

2.      Fill in the below on Normal Flora

Location

Common Species

Notes

Skin (eyes and ears)

 

 

 

 

 

Upper Respiratory Tract

(down to the epiglottis)

 

 

 

 

 

Lower Respiratory Tract

(epiglottis south)

 

 

 

Upper Gastrointestinal Tract (GI) (to the stomach)

 

 

 

 

Lower GI Tract Intestines to rectum

 

 

 

Lower Urinary and Reproductive Tract (south of the bladder, urethra and/or vagina)

 

Females

Males

 

Upper Urinary and Reproductive Tract (north of the bladder & cervix)

Females

Males

 

Blood, Heart, Internal Organs

 

 

 

Peritoneal, Pericardial, Thoracic Cavities

 

 

 

Joints

 

 

 

Brain and Spinal Cord

 

 

 

Placenta, Fetus

 

 

 

3.      What was your hypothesis concerning the hand washing experiment?

 

 

DATA:

 

Lab Partner

 

 

unwashed hand

 

15 second scrub

 

vigorous scrub

 

 antiseptic

 

#1 no soap

 

 

 

 

 

 

 

 

 

 

 

 

#2 liquid             soap

 

 

 

 

 

 

 

 

 

 

 

#3 transient        bacteria

 

 

 

 

 

 

 

 

 

 

 

Look at the class data.

Class Results for Handwashing

 

 

 

Lab Partner

 

No Wash

 

15 sec. scrub

 

vigorous wash

 

antiseptic

 

 No Soap

 

 

No Soap

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Liquid Soap

 

 Liquid

Soap

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Transient Flora

 Transient Flora

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

4.      Was your hypothesis supported? Why or Why not?

 

 

 

5.      On a separate sheet of graph paper, make a graph that displays the results of this data.

 

 

 

6.      Compare the effectiveness of initial scrub with the vigorous scrub.

 

 

 

7.      What was the effect of the antiseptic wash?

 

 

 

8.      What might explain differences amongst class results as far as the number of colonies that grew?

 

 

 

 

7. Discuss the effect of hand washing on transient versus residential bacteria.

 

 

  

 

 

8. How do these data impact healthcare practices? Find an article on the web about hand washing. Summarize the results and attach the article to this exercise.

 

 

 

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Bakersfield College | Kern Community College District | Dr. Janet Fulks
1801 Panorama Dr. - Bakersfield, CA 93305 - (661)395-4381
Date last updated 09/11/2010
Janet Fulks