ISOLATION AND CHARACTERIZATION OF Aeromonas spp FROM POND WATER AND FISHES IN ILE-IFE OSUN STATE, NIGERIA.

ABSTRACT

The study was carried out to isolate, characterize and investigate the antibiotic susceptibility pattern of Aeromonas species isolated from pond water and fish samples at Sabo and Iloro pond sites in Ile-Ife, Osun State. 

Physicochemical parameters of the water samples such as pH, temperature, total dissolved solid (TDS), dissolved oxygen (DO) and biochemical oxygen demand (BOD) were determined using standard methods. Aeromonas species was isolated by the spread plate technique for both water and fish intestine samples using Inositol Brilliant Green Bile agar. Antibiotics susceptibility pattern of the isolates was carried out on using the disc diffusion method. 

The physicochemical parameters results showed that the mean TDS values ranging between 238±23.23 and 422±23.23, highest mean pH value of 7.90±0.05 was observed at sabo (pond 2), the result for mean temperature fell within the range of 24˚C and 30˚C, DO values was lowest at iloro with a mean value of 0.24±0.38 and mean BOD values had a range within 0.04±0.42 and 3.01±0.42.  A total of 10 Aeromonas spp were isolated and identified, the antibiotics susceptibility test result revealed that the Aeromonas spp were 100% resistant to augumentin, cefuroxime and cefixime while 80% were susceptible to nitrofurantoin, ciprofloxacin and gentamicin. Also, 90% were susceptible to ofloxacin and only 10% to ceftazidime. 

This research study revealed that water and fish samples could serve as reservoir for Aeromonas spp. Moreso, the decrease in the antibiotics susceptibility to the tested antibiotics indicates the need to take effective measures in regulating activities around the ponds.

TABLE OF CONTENTS

Content                                                                                                                           Page

Title page                 i

Certification                  ii

Dedication                 iii

Acknowledgement                 iv

List of tables                             v

List of figures                 vi

Table of content                 vii

Abstract                  xii

CHAPTER ONE                 1

INTRODUCTION AND LITERATURE REVIEW                             1

Introduction                 1

Aim and objectives                 3

Literature review                 5

      1.3.1 Water                 5

1.3.2 Types of water                 5

1.3.3 Importance of water                 6

1.3.4 Water quality                 7

1.3.5 Aquaculture                             8

1.3.6. Water contamination                 9

1.3.7 Health implications of water contamination                 9

1.3.8 Contamination of water by microorganisms                 10

1.3.9 Genus Aeromonas                 11

1.3.10 Pathogenicity of Aeromonas spp                 12

1.3.11 Epidemiology of Aeromonas spp                 13

1.3.12 Antibiotics susceptibility of Aeromonas spp                 14

CHAPTER TWO                 16

MATERIALS AND METHOD                 16

2.1 Materials                 16

      2.1.1 Reagents                 16

      2.1.2 Glass wares                 16

      2.1.3 Culture media                 16

      2.1.4 Equipment’s                 17

2.2 Method                 17

      2.2.1 Sanitary survey/ study area                 17

      2.2.2 Sterilization and preparation of media and materials                 17

      2.2.3 Sample collection                 17

2.3 Physiochemical analysis                 18

      2.3.1 On site physiochemical analysis                 18

      2.3.1.1 Temperature                 18

      2.3.1.2 pH                 18

      2.3.1.3 Turbidity                 18

      2.3.2 Off site parameters                 18

      2.3.2.1 Dissolved oxygen                              18

      2.3.2.2 Biochemical oxygen demand                 19

2.4 Microbiological analysis                 19

      2.4.1 Enrichment                 19

      2.4.2 Serial dilution                 19

      2.4.3 Characterization and identification of bacterial isolates                 19

      2.4.3.1 Macroscopic morphology                 20

      2.4.3.2 Microscopic morphology                 20

2.5 Physiological and biochemical characterization of bacterial isolates                 20

      2.5.1 Oxidase test                 20

      2.5 2 Catalase test                 21

      2.5.3 Sugar fermentation test                 21

      2.5.3.1 Triple sugar ion test                 21

      2.5.3.2 Mannitol fermentation                 21

      2.5.3.3 Maltose fermentation                 22

      2.5.4 Sodium requirement for growth                 22

      2.5.5 Methyl red test                 22

      2.5.6 Voges proskauer test                 22

      2.5.7 Motility test                 23 

      2.5.8 Indole test                 23

      2.5.9 Decarboxylase test                 23

      2.5.9.1 Lysine decarboxylase test                 23

      2.5.9.2 Arginine decarboxylase test                 24

      2.5.9.3 Ornithine decarboxylase test                 24

2.6 Antibiotics sensitivity testing                 24

2.7 Statistical analysis                 25

CHAPTER THREE                 26

RESULTS                 26

3.1 Description of sampling sites                 26

3.2 Physiochemical analysis for the water samples                 26

      3.2.1 Total dissolved solid                 26

      3.2.2 Temperature                 26

      3.2.3 pH                 27

      3.2.4 Dissolved oxygen (DO)                 27

      3.2.5 Biological oxygen demand                 27

3.3 Microbiological analysis                 31

      3.3.1 Percentage occurrence of isolated Aeromonas spp                 31

      3.3.2 Samples collected from Sabo and Iloro ponds                 31

3.4 Comparing physicochemical quality of water samples collected from                  35

      Sabo and Iloro ponds

3.5 Morphological, cultural and biochemical identification of the                  35

      Aeromonas species

3.6 Antibiotic sensitivity testing of Aeromonas species                 37

      3.6.1 Single resistance pattern in Aeromonas spp                 37

      3.6.2 Multiple resistance pattern in Aeromonas spp                 37

CHAPTER FOUR                 39

4.1 DISCUSSION                 39

4.2 CONCLUSION                 43

4.3 RECOMMENDATION     43

REFRENCES                 45