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Occurrence and fate of antibiotic resistant bacteria in sewage

Contents

Preface
   
Summary and conclusions
  
Sammendrag og konklusioner
  
1. Introduction and project background
1.1 Project structure and objectives
1.2 What are antibiotics?
1.2.1 Classification
1.2.2 Mechanisms of action
1.3 What is antibiotic resistance?
1.3.1 Molecular mechanisms
1.3.2 Natural and acquired resistance
1.3.3 Acquisition by chromosomal mutations
1.3.4 Acquisition by horizontal gene transfer
1.3.5 Intracellular migration of resistance genes
1.3.6 Measurement of resistance in bacterial populations
1.4 The microbial threat
1.4.1 The emergence of resistance in human pathogenic bacteria
1.4.2 The spread of resistance among environmental bacteria
1.5 Spread of antibiotic resistance in sewage
1.5.1 Antibiotic selective pressure
1.5.2 Non-antibiotic selective pressure
1.5.3 Optimal conditions for horizontal gene transfer
    
2. Methodology
2.1 Sampling sites, times and methods
2.1.1 Sampling at sewers
2.1.2 Sampling at sewage treatment plants
2.2 Measurement of antibiotic resistance
2.2.1 Use of Acinetobacter as a bacterial indicator
2.2.2 Antibiotic susceptibility testing of Acinetobacter isolates
2.2.3 Enumeration of resistant coliforms in sewage
2.2.4 Enumeration of resistant acinetobacters in sewage
2.2.5 Enumeration of total culturable resistant bacteria in blue mussels
2.2.6 Enumeration of resistant E. coli in blue mussels
2.2.7 Statistical analysis
2.3 Identification and typing of bacteria and resistance genes
2.3.1 Identification of Acinetobacter at the genus level
2.3.2 Identification of Acinetobacter at the species level
2.3.3 Plasmid profiles
2.3.4 Ribotyping
2.3.5 Typing of tetracycline resistance genes
2.4 Experiments on transfer of tetracycline resistance
2.4.1 Bacterial strains
2.4.2 Mating experiments
2.5 Experiments on survival of multiple-resistant bacteria in natural waters
2.5.1 Bacterial strains
2.5.2 Laboratory seawater microcosms
2.5.3 In situ pond experiment
   
3. Effects of hospital and pharmaceutical waste effluent on the prevalence of resistant Acinetobacter in the recipient sewers
3.1 Effects of hospital waste effluent
3.2 Effects of pharmaceutical waste effluent
3.3 Conclusions
  
4. Effects of sewage treatment on total numbers and percentages of resistant bacteria
4.1 Effects on total numbers of resistant bacteria
4.2 Effects on percentages of resistant bacteria
4.3 Conclusions
   
5. Spread of resistant bacteria and resistance genes by municipal sewage effluents
5.1 Survival in the environment of resistant bacteria originating from sewage
5.1.1 Survival in laboratory seawater microcosms
5.1.2 Survival in a freshwater pond
5.2 Transfer of resistance genes from sewage to aquatic bacteria
5.2.1 Laboratory mating experiments
5.2.2 Distribution of tetracycline resistance genes
5.3 Occurrence of resistant bacteria in blue mussels exposed to treated sewage
5.3.1 Antibiotic resistance of total culturable bacteria in blue mussels
5.3.2 Antibiotic resistance of E. coli in blue mussels
5.4 Conclusions
    
6. Reference List
        
Annex 1. Scientific papers and dissemination of results

 

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