ABSTRACT

Staphylococcus aureus is an important human pathogen that causes serious infections both in hospitals and communities globally due to its multi-drug resistance tendency. This study was undertaken to determine the prevalence of Staphylococcus aureus  and antibiotic sensitivity pattern among pigs and pig farmers in Michael Okpara University of Agriculture, Umudike (MOUAU). Sixty (60) swab samples were collected from various sites of the pigs of 2 species (Duroc and Large-white) and from the nostrils of the pig farmers. The samples were subjected to standard microbiological techniques to identify Staphylococcus aureus. Resistance to Methicillin was determined by using Cefoxitin (30µg). A total of 48 isolates of Staphylococcus species were recovered representing 80% (48/60) of total isolates and MRSA carriage of 0% (0/48) was obtained showing no prevalence of MRSA. Large white specie of the pigs had a higher prevalence of 70.83% (34/48) compared with the isolates from Duroc pigs which had a lower prevalence of 29.16% (14/48). The antibiotic susceptibility profiles of the isolates to the commonly used drugs showed high resistance to Ceftazidime (95.83%) followed by Erythromycin (47.90%). All isolates were susceptible to Cefuroxime (100%), Ceftriaxone (100%) and Cefoxitin (100%). The prevalence of Staphylococcus aureus was more in the nasal discharge of the pigs (61.54%) than in the pig farmers (38.46%). This should therefore call for urgent intervention because pigs can serve as reservoir through which infections related to Staphylococcus aureus  can spread to other animals, humans and community at large. Therefore, proper hygiene practices, control of indiscriminate use of antibiotics, and frequent screening of this population for  Staphylococcus aureus  related infections, are hereby recommended both for prevention and control of livestock acquired Staphylococcus aureus infections.

TABLE OF CONTENTS

Title page                        i

Certification                                                                ii  

Dedication                     iii

Acknowledgment                      iv

Table of contents                       v

Abstract                       ix

CHAPTER ONE

1.0 INTRODUCTION 1

1.1    Aims and objectives of the study 3

CHAPTER TWO

2.0 LITERATURE REVIEW 4

2.1 Staphylococcaceae 4

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2.2 Staphylococcus aureus 5

2.3 Morphology and identification of Staphylococcus aureus        5

2.4 Biology and pathogenesis of Staphylococcus aureus 6

2.5 Methicillin Resistant Staphylococcus aureus (MRSA) 7

2.6 Mechanism of resistance of MRSA 9

2.7 Historical Background of Methicillin Resistant Staphylococcus aureus (MRSA) 10

2.8 Epidemiology of MRSA 11

2.9 MRSA and its association with Pigs 12

2.10      Antibiotics 12

2.10.1   Classes of Antibiotics 13

2.10.2 β-Lactam Antibiotics 13

2.11 Penicillin 14

2.12 Methicillin 15

2.13 Mode of action of β-Lactam Antibiotics 16

2.14 Mechanism of resistance of β-Lactam antibiotics 17

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CHAPTER THREE

3.0 MATERIALS AND METHODS 18

3.1.1 Culture media 18

3.1.2     Reagents used 18

3.1.3    Equipment and materials used 18

3.1.4    Antibiotic discs used 18

3.2 Collection of samples 18

3.3 Media preparation 19

3.4 Characterization and identification of the isolates 19

3.4.1 Growth on Mannitol Salt Agar (MSA) 19

3.4.2 Growth on blood agar (Sub-culturing of the isolates) 20

3.4.3 Identification of Staphylococcus aureus 20

3.5 Gram staining 20

3.6 Biochemical characterization of isolates 21

3.6.1 Catalase Test 21

3.6.2 Coagulase Test 21

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3.7 Antibiotic Sensitivity Testing 22

3.8 Detection of MRSA (using disc diffusion method)  22

CHAPTER FOUR

RESULTS 23

CHAPTER FIVE

5.0 DISCUSSION AND CONCLUSION 32

5.1 Discussion 32

5.2 Conclusion 33

References 35