ABSTRACT

Methicillin-resistant Staphylococcus aureus (MRSA) has evolved as a major health care-acquired pathogen worldwide into one that can be found in the community. This study was carried out to determine the carriage rate of MRSA in the nostrils of students of Michael Okpara University of Agriculture, Umudike. Of the 100 samples analysed, 65(65 of 100) were positive for S. aureus, Some of the S. aureus isolates that showed resistance to many antimicrobial agents were found to be methicillin-resistant. The prevalence of MRSA nasal carriage was 9.2% (6 of 65) detected by oxacillin disk diffusion methods. MRSA was identified in 3.1% (2 of 65) of males and 6.1% (4 of 65) of females. All the MRSA isolates showed multi-drug resistance to at least four antibiotics tested. However, MRSA strains were highly sensitive to Levofloxacin. The highest rates of resistance were observed for Amoxicillin and Ampicillin.

TABLE OF CONTENTS

Title Page i

Certification ii

Dedication iii

Acknowledgements iv

Table of Contents v

List of Tables and Figures viii

Abstract ix

CHAPTER ONE

Introduction

1.1 Introduction 1

1.2 Aim and Objectives 3

CHAPTER TWO

Literature review

2.1 Staphylococcus aureus 4

2.1.1 Pathogenesis of S. aureus 4

2.1.2 Mode of transmission of S. aureus 5

2.1.3 The role of nasal carriage of S.aureus in Staphylococcus aureus

Infections 6

2.1.4 Virulence factors in S. aureus 6

2.1.5 Mode of reproduction of S. aureus 8

2.1.6 Antibiotic susceptibility and resistance of S. aureus 9

2.2 Methicillin-resistant Staphylococcus aureus 10

2.2.1 Hospital-acquired and Community-Acquired MRSA 11

2.2.2 Clinical implications of MRSA 12

2.2.3 Mechanism of methicillin resistance 12

2.2.4 Mode of transmission 13

2.2.5 Risk factors for CA-MRSA 13

2.2.6 Prevention and control of CA-MRSA 15

CHAPTER THREE

Materials and methods

3.1 Study Location and design 16\

3.2 Sample collection 16

3.3 Sterilization of materials 16

3.4 Preparation of culture media 17

3.5 Inoculation of the nasal sample 17

3.6 Identification of Staphylococcus aureus 17

3.7 Preparation of turbidity standard equivalent to McFarland 0.5 18

3.8 Antibiotic Susceptibility test 19

3.9 Detection of methicillin resistance 19

CHAPTER FOUR

Results 20

CHAPTER FIVE

Discussion, Conclusion and Recommendation

5.1 Discussion 29

5.2 Conclusion 30

5.3 Recommendation 31

REFERENCES

APPENDIX

LIST OF TABLES AND FIGURES

Table Title Page

1 Characterization and identification of S. aureus 21

2 Incidence of S. aureus among the sampled population 22

3 Sex distribution and antibiotic susceptibility profile of the Staphylococcus aureus isolates 23

4 Antimicrobial susceptibility profile of Staphylococcus aureus from the nasal passages of students 25

5 Sex distribution and diameter zone of inhibition of oxacillin 26

6 Percentage of isolates resistant to oxacillin 27

Figure Title Page

1 Susceptibility pattern of identified MRSA 28