Invitro Determination Of Bactericidal Effects Of Garlic On Staphyloccus aureus, Streptococcus spp., Escherichia coli AND Salmonella spp.

ABSTRACT

This study was to determine the bactericidal effects of Garlic (Allium sativum) on Staphylococcus aureus, Streptococcus spp. Escherichia coli and Salmonella spp. The fresh Garlic (Allium sativum), in bulbs forms were obtained from Ahieke Market. The test organisms used in this research consisted of two Gram-positive and two Gram-negative bacteria isolates obtained from stool, sputum samples, and skin swabs. The test organisms used included; Escherichia coli, Staphylococcus aureus, Salmonella species and Streptococcus species. Three (3) solvents (hot water, cold water and methanol) were used to get a comparative result. Agar well diffusion method was used to determine the bactericidal effects of the Garlic (Allium sativum) on the test organisms. The methanolic extract of Garlic (Allium sativum) was found to exhibit high degrees of antibacterial activities against the test isolates. This was shown by the clear zones of inhibition produced by the methanolic extract on the test microorganisms. The highest in-vitro antibacterial activity is 16mm which was exhibited by the methanolic extract at the highest concentration of 200mg/ml against Staphylococcus aureus followed by Salmonella species 14(200mg/ml), while no antibacterial activity (0.0mm) was exhibited by the Methanolic extract at the lowest concentration of 50mg/ml against all the test organisms. It was also observed in this study that the Garlic (Allium sativum) extract had both a bacteristatic and bactericidal activity when tested in vitro using methanolic preparation of garlic extract. Therefore, garlic may be used successfully for treating food poisoning causative agent like Staphylococcus aureus. It may be effective on other microbes on gram positive and gram-negative bacteria, so that further in vivo and in vitro studies are necessary. The standard antibiotics (Ciprofloxacin and Chloramphenicol) used as control inhibited the test bacteria and fungi respectively; it had higher inhibitory activity compared to the Garlic (Allium sativum) extracts. More importantly, there is need for detailed scientific study of traditional medical practices to ensure that valuable therapeutic knowledge of some plants is preserved and also to provide scientific evidence for their efficacies.

TABLE OF CONTENTS

Title Page ﾿   ﾿   i

Certification ﾿ iii

Dedication ﾿ iv

Acknowledgement ﾿ v

Table of Contents ﾿ vi

List of Tables ﾿ vii

Abstract ﾿ ix

CHAPTER ONE

1.0 ﾿ Introduction ﾿ 1

1.1 ﾿ Background of Study ﾿ 1

1.2 ﾿ Aim of Study ﾿ 2

1.3 ﾿ Specific Objectives ﾿ 2

CHAPTER TWO

2.0 ﾿ Literature Review ﾿ 3

2.1 ﾿ Brief Description of Garlic (Allium sativum) ﾿ 3

2.2 ﾿ Brief History of Garlic (Allium sativum) ﾿ 3

2.3 ﾿ Chemical Constituents of Garlic (Allium sativum) ﾿ 4

2.4 ﾿ Medicinal Values of Garlic (Allium sativum) ﾿ 5

2.4.1 ﾿ Treatment Cardiovascular Disease ﾿ 5

2.4.2 ﾿ Reduces High Blood Pressure/Hypertension ﾿ 6

2.4.4 ﾿ Natural Blood Thinner ﾿ 6

2.4.5 ﾿ Prevents Diabetes ﾿ 7

2.5 ﾿ Antimicrobial Properties of Garlic (Allium sativum) ﾿ 7

2.5.1 ﾿ Antiviral Effect ﾿ 8

2.5.2 ﾿ Antibacterial Effect ﾿ 8

2.5.3 ﾿ Adverse Effects of Garlic ﾿ 9

2.6 ﾿ Classification of Phytochemicals ﾿ 9

2.6.1 ﾿ Tannins ﾿ 9

2.6.2 ﾿ Flavonoids ﾿ 10

2.6.3 ﾿ Organic Acids ﾿ 10

2.6.4 ﾿ Phenols ﾿ 10

2.6.5 ﾿ Nitrogenous Compounds ﾿ 10

2.6.6 ﾿ Terpenoids ﾿ 11

2.7 ﾿ Biology and Pathogenecity of Test Organisms ﾿ 11

2.7.1 ﾿ Salmonella ﾿ 11

2.7.2 ﾿ Staphylococcus aureus ﾿ 12

2.7.2.1 ﾿ Source and Transmission of Staphylococcus aureus ﾿ 12

2.7.2.2 ﾿ Diseases Caused by Staphylococcus aureus ﾿ 13

2.7.3 ﾿ Escherichia coli ﾿ 13

2.7.3.1 ﾿ Diseases Caused by Escherichia coli O157: H7 ﾿ 14

2.7.4 ﾿ Streptococcus spp ﾿ 14

2.7.4.1 ﾿ Streptococcus pneumonia ﾿ 15

CHAPTER THREE

3.0 ﾿ Materials and Methods ﾿ 17

3.1 ﾿ Sources of Materials ﾿ 17

3.2 ﾿ Sterilization of Materials ﾿ 17

3.3 ﾿ Media Used ﾿ 17

3.4 ﾿ Preparation of Garlic Extracts ﾿ 17

3.4.1 ﾿ Preparation of Different Concentration of Extract ﾿ 18

3.4.1.1 ﾿ Cold Water Extract ﾿ 18

3.4.1.2 ﾿ Hot Water Extract ﾿ 18

3.4.1.3 ﾿ Methanol Extract ﾿ 18

3.4.3 ﾿ Media Preparation ﾿ 18

3.4.4 ﾿ Agar Well Diffusion Method ﾿ 18

3.5 ﾿ Determination of Antibacterial Activity ﾿ 19

3.6 ﾿ Determination of Minimum Inhibitory Concentration (MIC) ﾿ 19

3.6.1 ﾿ Agar Well Diffusion Method ﾿ 19

3.6.2 ﾿ Disc Diffusion Method ﾿ 20

3.7 ﾿ Determination of Minimum Bactericidal Concentration (MBC) ﾿ 21

CHAPTER FOUR

4.0 Results ﾿ 21

CHAPTER FIVE

5.0 ﾿ Discussion, Conclusion and Recommendation ﾿ 27

5.1 ﾿ Discussion ﾿ 27

5.2 ﾿ Conclusion ﾿ 29

5.3 ﾿ Recommendations ﾿ 30

﾿ References