Fate,Abundance and Characterization of Tetracycline Resistant Bacteria in a Wastewater Treatment Plant

声明

ACKNOWLEDGEMENTS

ABSTRACT

摘要

LIST OF ABBREVIATIONS

TABLE OF CONTENTS

LIST OF TABLES

LIST OF FIGURES

Chapter 1 Literature Review

1．1 Introduction to Antibiotic Resistance

1．1．1 Mechanism of Action of Antibiotic Drugs

1．1．2 Mechanisms of Bacteria Resistance to Antibiotic Drugs

1．2 Tetracyclines

1．2．1 Structure of Tetracyclines

1．2．2 Mode of Action

1．2．3 Function and Use of Tetracyclines

1．3 Tetracycline Resistant Bacteria

1．3．1 Mechanism of Bacteria Resistance to Tetracycline

1．4 Wastewater Treatment Plants

1．4．1 Antibiotics and Antibiotic Resistant Bacteria in Wastewater Treatment Plants

1．4．2 Tetracycline Resistance in Aquatic Environment

1．4．3 The Role of WWTPs in the Proliferation of Antibiotic Resistant Bacteria／Genes

1．5 Aim and Significance of the Study

1．5．1 Problem Statement

1．5．2 Hypothesis

1．5．3 Research Objectives

Chapter 2 Materials and Methods

2．1 Reagents and Instruments

2．1．1 Chemicals and Reagents

2．1．2 Instruments

2．2 Experimental Design and Procedure

2．2．1 Wastewater Sampling

2．2．2 Tetracycline Solution

2．2．3 Media Preparation

2．3 Isolation and Viable Count of Tetracycline Resistant Bacteria

2．3．1 Isolation of TRB

2．3．2 Cultivation Conditions

2．3．3 Counting Bacteria

2．4 Tetracycline Resistance Rates

2．5 Bacterial Removal Rate

2．6 Bacteria Characterization

2．7 Molecular Identification of Tetracycline Resistant Bacteria

2．7．1 DNA Extraction from Isolated Culture

2．7．2 16S rDNA Analysis of Isolated Cultivable Bacteria

2．7．3 Sequencing and Phylogenetic Analysis of Isolates

2．8 Growth Study of the Selected Bacteria Strains

2．8．1 Optimization of Growth Conditions

2．8．2 Determination of Bacterial Cell Growth

2．8．3 Calculations

Chapter 3 Results and Discussion

3．1 Enumeration of Cultivable Bacteria by Viable Plate Count

3．2 Abundance of TRB in WWTP

3．3 Fate of TRB in WWTP

3．3．1 Effect of Different Operational Units on TRB Number

3．3．2 Effect of Different Operational Units on TRB Removal Rate

3．3．3 Effect of Different Operational Units on TRB Resistance Rate

3．3．4 Role of Wastewater Disinfection on TC Resistance Prevalence

3．4 Impact of TC Concentrations on TRB

3．5 Characterization of TRB from WWTP

3．5．1 Phenotypic Characterization of the Isolates

3．5．2 Phylogenetic Affiliation of the Isolates

3．5．3 Gram Staining of the Isolates

3．5．4 Growth Studies of Bacteria Isolates

3．5．5 Molecular Analysis of TRB from WWTP

Chapter 4 Conclusions and Future Study

4．1 Conclusion

4．2 Future Study

References

Appendix