ABSTRACT

This study was carried out to determine the occurrence of Salmonella and Shigella species in broiler chicken carcasses and their antimicrobial susceptibility pattern. A total of 59 Salmonella and Shigella species isolates was isolated from broiler chicken carcasses samples. 28 were from Salmonella species whereas 31 were from Shigella species. The details of these isolates comprises of Salmonella enterica (17), Salmonella enteritidis (11), Shigella flexneri (21), and Shigella sonnel (10). From the findings in this study, it was observed that Shigella flexneri is the most frequently occurring isolate from the chicken carcasses samples with the highest percentage occurrence of (35.7%), followed by Salmonella enterca (28.8%), then Salmonella enteritidis (18.6%) and Shigella sonnel (16.9%). This observation underscores the need for improved carcass handling practices on farm and at slaughter points in order to eliminate/minimize contamination and its subsequent food safety challenges and risks to human health. The total viable bacterial mean counts from chicken carcasses samples ranging from 2.7×104 cfu/g to 8.6×105 cfu/g. Total Salmonella plate count ranges from 6.5×104 cfu/g to 2.9×105 cfu/g, Total Shigella plate count ranges from 2.7×104 cfu/g to 1.2×106 cfu/g. Results of the antibiotic sensitivity tests for isolates indicated that 10 % of the isolates tested (n=59) had at least one or multiple resistance to the antibiotics tested. The use of antibiotics in the local farms must be managed to reduce the incidence of antibiotic resistance. The isolation of Salmonella and Shigella species from broiler chicken carcasses is an indication that chicken carcasses harbors pathogenic organisms and the processing procedures must be evaluated with the objective of identifying critical control points in the production process in order to reduce the rate of contamination of poultry products.

TABLE OF CONTENTS

Title Page   i

Certification ii

Dedication iii

Acknowledgement iv

Table of Contents v

List of Tables vii

Abstract viii

CHAPTER ONE

1.0 Introduction 1

1.1 Aims and Objectives 4

CHAPTER TWO

2.0 Literature Review 5

2.1 Salmonella Sp 6

2.1.1 Incidence of Salmonella sp. Contamination in chicken 6

2.1.2 Epidemiology of Salmonella sp. in Poultry and Poultry Products 8

2.1.3 Prevalence of Salmonella sp. in Poultry Flocks 8

2.1.4 Prevalence of Salmonella sp. in Poultry Products at the Processing Plant 9

2.1.5 Distribution of Salmonella sp. Serotypes 11

2.1.6 Control and Prevention 12

2.2 Shigella 15

2.2.1 Epidemiology 15

2.2.2 Symptoms 16

2.2.3 Control and Prevention of Shigella 16

2.3 Antimicrobial Resistance 17

2.3.1 Antibiotics and Antimicrobials 17

2.3.2 Antibiotic Resistance Strategies 18

2.3.3 Biological versus Clinical Resistance 19

2.3.4 Acquired Resistance 20

2.3.5 Detecting antimicrobial resistance 20

2.3.6 Test Methods in Detecting Antimicrobial Resistance 22

CHAPTER THREE

3.0 Materials and Methods 23

3.2 Collection of Samples 23

3.2.1 Preparation of Samples 23

3.3 Sterilization of Materials 23

3.4 Preparation of Culture Media 23

3.5 Inoculation and Isolation 24

3.6 Purification of Isolates 24

3.7 Identification of the Isolates 24

3.8 Gram Staining 25

3.9 Biochemical Test 25

3.9.1 Catalase Test 25

3.9.2 Indole Test 25

3.9.3 Citrate Utilization Test 26

3.9.4 Hydrogen Sulphide (H2S) Production Test 26

3.9.5 Starch Hydrolysis 26

3.9.6 Motility, Indole, Urease (MIU) 27

3.10 Antibiotic Susceptibility Testing 27

CHAPTER FOUR

4.0 Results 29

CHAPTER FIVE

5.0 Discussion and Conclusion 36

5.1 Discussion 36

5.2 Conclusion 38

5.3 Recommendations 38