ABSTRACT

Bacillus species was isolated from soil samples using spread plate method on nutrient agar while peptone water was used as the production medium. The production of bacitracin was authenticated by antimicrobial activity against Klebsiella pneumoniae, Escherichia coli, Streptococcus pyogenes, Staphylococcus aureus and Pseudomonas aeruginosa. This was done using agar well diffusion method. After the production of bacitracin by Bacillus species, the minimum bactericidal concentration of the produced bacitracin was evaluated, using 70%, 60%, 50%, 30% and 20% each of the diluted bacitracin aliquot on Klebsiella pneumoniae, Escherichia coli, Streptococcus pyogenes, Staphylococcus aureus and Pseudomonas aeruginosa. The zone diameter against the respective was calculated in duplicates and the mean diameter was obtained. Highest zone inhibition diameter was observed against Streptococcus pyogenes with a mean inhibition diameter of 10mm. Next in line was Staphylococcus aureus with a mean inhibition diameter of 9mm. After this came Escherichia coli with a mean inhibition diameter of 8mm, Klebsiella pneumoniae with a mean inhibition diameter of 7mm and lastly, Pseudomonas aeruginosa with a mean inhibition diameter of 6mm.  For Escherichia coli, the MIC was at 50% and minimum bactericidal concentration was at 50%. For Pseudomonas aeruginosa MIC was at 60% and minimum bactericidal concentration percentage was at 60%. For Staphylococcus aureus MIC was at 30% and MBC was at 30%. For Klebsiella pneumoniae, MIC was at 60% while MBC was at 60%. For Streptococcus pyogenes, MIC was at 30% while MBC was at 30%. Bacitracin is very effective against Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Streptococcus pyogenes and Escherichia coli and as such can be used effectively in the treatment of diseases caused by these organisms.

TABLE OF CONTENTS

Certification ii

Dedication iii

Acknowledgements iv

Table of Contents v

List of Tables viii

Abstract                                                                                                                                 ix

Chapter One

1.0        Introduction…………………………………………………………………..1

1.1 Aim …………………………………………………………………………..2

1.2 Objectives………………………………………………………………….2

Chapter Two

2.0        Literature review……………………………………………………………3

2.1 Bacitracin…………………………………………………………………….3

2.1.1 History 3

2.1.2 Synthesis 3

2.1.3 Composition 4

2.1.4 Spectrum of activity and susceptibility data 4

2.1.5 Mechanism of action 4

2.1.6 Clinical use 5

2.2 Bacillus subtilis 9

2.2.1 Habitat 9

2.2.2 Reproduction 10

2.2.3 Chromosomal replication 10

2.2.4 Genome 11

2.2.5 Transformation 12

2.2.6 Uses 14

2.2.7 Safety 15

2.2.7.1 In humans 16

2.2.7.2 In animals 17

Chapter Three

3.0 Materials and methods 17

3.1 Source of material and collection 17

3.2 Preparation of culture media 17

3.3 Sterilization of materials 17

3.4. Isolation of bacillus specie 18

3.5. Identification of the isolate 18

3.5.1 Morphological appearance 18

3.5.2 Gram reaction 18

3.5.3 Endospore stain 19

3.5.4 Biochemical characteristics 20

3.5.5    Growth at 550C 20

3.6. Screening for crude bacitracin production by Bacillus specie 20

3.6.1. Antimicrobial testing of bacitracin produced by Bacillus specie 20

3.7. Minimum bactericidal concentration 21

Chapter Four

4.0. Results 30

Chapter Five

5.1. Discussion 31

5.2. Conclusion 32

References 34

Appendix