ABSTRACT

Ethanol, Bleach and phenolic are three kinds of disinfectants which have been widely used in common laboratories. In this study, the minimum inhibitory concentration (MIC) experiment on these three disinfectants efficiency was conducted against Staphylococcus aureus using agar hold diffusion method. Different concentrations of bleach (1%, 2% 3%, 4% and 5%) were used on Staphylococcus aureus. Also (50%, 60%, 70%, 85% and 95%) of ethanol as well as (5%, 10%, 20%, 25%, and 30%) phenolic were used. Differences in concentrations tested was because, the original concentrations of the disinfectants differs. After 24 hours of incubation at 370c, the results showed that all the disinfectants inhibited the growth of the test organism in their concentrated forms. The diameter of zone of inhibitions was measured around each well by using a ruler in millimeters, using different concentrations, their efficacies varied. The results showed that 30% phenolic had the best efficiency against the test organism (Staphylococcus aureus) and showed the (MIC) value at 5%, and 5% bleach had a better effect on the test organism than ethanol and showed the MIC value at 4%, ethanol showed  least sensitivity. 70% concentration of ethanol gave the highest effect on the test organism, while at 60%conc. of ethanol showed the minimum inhibitory concentration (MIC).

TABLE OF CONTENTS

Title page i

Certification ii

Dedication iii

Acknowledgements iv

Table of Contents v

List of Table                                    vi

List of Figures vii

Abstract viii

CHAPTER ONE: INTRODUCTION

1.1 Background of study 1

1.2 Objectives of the Study 3

1.3 Statement of Problem 4

1.4 Justification 4

CHAPTER TWO: LITERATURE REVIEW

2.1 General Concept 5

2.1 History of Disinfections 6

2.2 About Disinfectants 7

2.3 Types of Disinfectants 7

2.4 Properties of a Disinfectant 13

2.5 General Features of Disinfectants 14

2.6 General Features of the Test Organism 15

2.7 Mechanism of Actions of Disinfectants against Bacteria 15

2.8 Resistant Action of Bacteria 16

2.9 Advantages and Disadvantages of Disinfectants 17

CHAPTER THREE: MATERIAL AND METHOD

3.1 Collection of Materials and Sample 21

3.2 Preparation of Media 22

3.3 Identification of Isolates 23

3.4 Biochemical Test 24

3.5 Antibacterial Activity Testing 26

3.5.1 Preparation of Disinfectants 26

3.5.2 Antimicrobial Susceptibility Testing (Using Kirby Bauer Diffusion Assay Well Method. 

3.6 Determination of MinimumInhibitory Concentration (MIC) Using the Broth Dilution Method 28

CHAPTER FOUR

4.0 RESULTS 30

CHAPTER FIVE

5.0 Discussion 34

5.1 Recommendations 37

5.2 Conclusion 37

REFERENCE

APPENDIX 1

APPENDIX I

APPENDIX III