Chemistry Lab Report on the Importance of Hand Washing

Abstract

This lab experiment is centered on the critical need for effective hand washing as a way of reducing the amount of bacteria accrued within the hands of an individual. Hand washing is initially viewed as an efficient technique for inhibition of pathogen transmission. However, it’s not conclusive that this technique coupled with the use of soap is very efficient at the reduction of contamination with pathogens as opposed to using water only. In this lab experiment, 46 students contaminated their hands deliberately. At random, they were then allocated to hand washing with water only as well hand washing with water and soap. The time duration taken during the hand washing exercise was recorded and also the bacteria count determined both for after and pre – washing.

This was duly repeated for each and every student, some with the help of the instructor and some on themselves noting the various observations they made on the presence of the Gram purple bacteria. The students were exposed to the fact that hands harbor microorganisms that potentially leads to bacterial infection as well as diseases. In addition, the pathogens that cohabit the hands lead to the contamination of the lab processes if aseptic techniques are not adhered to for instance, wearing of gloves.

Prior to birth, any individual’s skin is deemed as sterile. As birth occurs and later, the individual’s skin is occupied by pathogens as well as microorganisms, the collection of the microorganisms that stays permanently on the individual’s skin and does not cause potential harm to a healthy living human being is known as the residential flora. This set of pathogens is very difficult and hard to eliminate as they are usually located within the hair follicles and the deeper epidermal layers. The other type of microorganisms known as transient flora is considered to be temporarily present on the skin and it is superficially located. The latter is easy to remove as opposed to the former. The former exists due to a symbiotic relationship with the host. Under competition for resources with the pathogenic microorganisms, it provides benefits to the host.

Keywords: Hygiene, skin, transient and permanent flora, experiment, Gram bacteria

Introduction

Efficient hand washing techniques has the ability of eliminating the transient flora from the surface of the hands as well as diminishes the presence of the permanent flora. Serious risk infections would be experienced if these pathogens were allowed into the body tissues. The objective of hand washing is to eliminate the transient pathogens and to lower the levels of permanent pathogens. The most frequently missed parts of the hand during a washing exercise are the wrists, nails and backs. Caution must be taken to ascertain that the frequently used hand is washed as well as the other.

Antibacterial products are often utilized in disinfecting hands but effective hand washing is normally deemed appropriate. Numerous products are composed of 8%chlorohexadine gluconate which has the merit of residual activity. Other product as 11% povidone iodine is employed in the cases of allergic reactions to the former. The hypothesis being examined in this lab experiment is the null hypothesis. The development and promotion of improved hand hygiene practices has been recognized as a significant public health practice.

However, its unclear how much hand hygiene is needed to interrupt transmission of the micoorganisms. In particular it has not been conclusively shown whether the use of soap is essential to eliminate pathogens from the hands. In recent hygiene promotion campaigns specifically in low income settings it has not been unanimously agreed on the use of soap. Numerous studies have compared distinct hand hygiene methods in hospital settings. In contrast, few studies have been published on the effect of hand hygiene on bacterial contamination of hands in the community. Hoque et al discovered that a greater variety of hand cleansing in poor settings are effective in reducing the contamination with coliform bacteria on hands. In a small randomized trial, the same author reported that soap may be more effective than water in the reduction of the coliform bacteria. Luby et al found that a simple microbiological method with three fingers directly imprinting a MacConkey agar for thermo tolerant coliforms was unable to distinguish between households who were given soap during a large randomized hand washing trial and control households. They concluded that the method was unsuitable for the evaluation of hand washing practices.

Methods

Initially the number of colonies on each agar plate was determined by estimating the size in millimeters and the data recorded. Each and every student then prepared their own Gram stained slides, each time using a pair of forceps to hold the slide for all manipulations involving the dyes. Each student prepared a heat – fixed smear of bacteria by taking a clean slide out of the tub and flaming off any alcohol, the slide was further allowed to cool after which it was labeled with a pencil. Using a sterile loop, a small amount of bacterial colony was taken from the agar plate and placed on the slide, emulsification was then done using a small drop of sterile saline and the liquid spread over an area of about 1 cm square. The air smear was then gently dried over a Bunsen burner flame.

The dried slide was then heat fixed by passing it three times through the hot parts of the Bunsen flame with the smear side facing up after which it was allowed to cool. At the staining rack the smear was covered with a few drops of crystal violet for 60 seconds, pouring off the excess crystal violet and rinsing with a gentle stream of running tap water. The smear was then covered with iodine and left for 45 seconds. The excess iodine was then poured off, washing down both front and back of the slides with alcohol solution and instantly under a gentle stream of running tap water. It was further counterstained with safranin for 30 seconds after which the any excess stain were washed off with water and the slide gently blotted to dry between the sheets of blotting paper. The slide was then viewed keeping in mind which side was facing up and then the Gram stain and morphology of the bacterial cells described.

This experiment was performed in the laboratory with 46 students. With the aid of a pre – determined random sequence, unknown to the students, the instructor asked the students to obtain the bacterial count on their hands before and after washing their hands with soap and water as well as with water only. Each student underwent this procedure within a definite time interval as estimated by the timer and the bacterial colonies recorded. Some students were assisted with the instructor to help identify the presence of the Gram bacteria on their hands whether positive or negative while others were able to do so for themselves. The students were then issued with a paper towel to dry their hands. During the entire experiment, the observations noted by the students were recorded in the comments section.

A total collection of 46 samples were collected for laboratory further analysis. 14 samples contained those students who didn’t use soap during hand washing while 32 samples composed of those students who used soap during the hand washing exercise. At the laboratory the samples were kept into test tubes of 5 ml using aseptic techniques. The samples were incubated for some time at around 40 degrees. All the samples were then streaked onto the MacConkey agar which functions as a selective media to obtain a distinction between coliforms and non – lactose fermenters, whilst inhibiting gram – positive cocci. The existence of bacterial contamination in the two study cases was analysed using logistic regression. Since the same students repeatedly underwent trials, within the objective, the issue of correlation was estimated by the use of generalized equations with strong standard errors.

Results and Discussion

The Gram positive bacteria upon addition of alcohol, the layer of the peptidoglycan was dehydrated which in turn trapped the CVI complex. This caused the Gram positive bacteria to appear as purple in color as the CVI complex was being retained. The addition of alcohol was not more than 15 seconds as it would lead to the breakage of the cell wall of the bacteria, thus resulting in stain to be observed. The slides were washed with water and dried off. The use of safranin to counterstain both smears enabled the Gram negative bacteria to be visualized easily as it was capable of staining pink in color. The Gram positive bacteria doesn’t stain pink on the introduction of safranin because the peptidoglycan layer already contains the CVI complex. The specimen were finally observed using a microscope under oil – immersion objective lenses. This particular lens have more mirrors inside and requires the use of oil to refract light rays towards the center of the lenses.

The most common organism observed was the Gram bacteria which were either positive or negative in most cases. The effect of hand washing with soap compared to hand washing with water only was observed and noted that hand washing with soap reduced the occurrence of bacteria greatly. Hand washing with soap was also found to be very efficient in the reduction of contamination and specifically the Gram bacteria. The statistical support for an earlier assumption that hand washing without soap was effective was observed to be low and other estimates.

The students took an average of 26 seconds (standard deviation 4.5) to wash their hands with water alone and an average of 36 seconds (standard deviation 7.3) to wash their hands with water and soap. Hand washing with soap was observed to be longer than hand washing with water only. It seemed that the large difference contributed immensely to the removal of bacteria with soap having a greater potential. Improved control over the experiment was observed with minimal effects on generalizability since the experiment aimed at the proof of a principle. Majority of the students observed gram positive bacteria while others didn’t observe anything with the least having gram negative bacteria. Therefore it appeared reasonable to assume that hand washing with soap also reduces bacterial load since from the results of the majority of the students it’s clear that the colonies greatly reduced after hand washing with soap as opposed to water only.

Conclusion

From the results it’s possible to conclude that hand washing with soap is highly efficient in the elimination of bacteria from hands as compared to hand washing with water only. The positive connection between hand hygiene method and bacterial hand contamination proves that the occurrence of bacteria indicator levels can also be employed to closely examine alterations in the hygiene behavior of the world population. Hygiene behavior is difficult to measure since individuals tend to change their usual behaviors when under examination. The microbiological method used in this experiment was observed to be cost effective and reliable. It’s also the simplest method one can wish to use.

We can conclude further that gram staining is the efficient method of distinguishing between gram positive and gram negative bacteria. In this experiment, we were provided with some materials to help us for achieving the aim of the experiment such as crystal violet, grams’s iodine, 95% ethyl alcohol, safranin and microscope slides. However, before doing the experiment, we absolutely paid attention to the precautions and aslo to eliminate the errors such as the preparation of the smear from cultures of the microorganisms, heat fixing the smears and so on.