Chlorine disinfection promotes the exchange of antibiotic resistant genes (ARGs) across bacterial...

1. Inter-Genus exchange

1.1. Mechanism?

1.1.1. ARGs are transferred between different genera of bacteria

1.2. Examples of bacterial genera involved?

1.2.1. Escherichia coli, Salmonella aberdeen, Pseudomonas aeruginosa, and Enterococcus faecalis

1.3. Consequences for bacterial evolution?

1.3.1. The main consequence of bacterial evolution is the emergence of new strains of bacteria that have enhanced antiobiotic-resistant capabilities

2. Chlorine-injured pathogens

2.1. Definition?

2.1.1. Chlorine-injured pathogens are bacteria that survive chlorine disinfection but are stressed and damaged

2.2. Behavior and survival?

2.2.1. Chlorine-injured pathogens may enter a viable but non-culturable state, making them harder to detect

2.3. Role in promoting ARG exchange?

2.3.1. Chlorine stress can make bacteria more likely to take up and incorporate ARGs

2.4. Survival mechanisms?

2.4.1. Bacteria that survive chlorine disinfection rely on signal proteins to activate repair mechanisms and adapt to the stress conditions. These proteins are critical for the repair of damaged DNA and membranes (Chapter 4)

2.5. Membrane damage?

2.5.1. Chlorine can injure bacteria, which can lead to compromised cell membranes. These stressed cells may have an increased permeability, making them more likely to take up ARGs through transformation (Chapter 11)

3. Public health implications

3.1. Risk of antiobioic-resistant infections?

3.1.1. There is an increased prevalence of resistant bacteria, which leads to harder-to-treat infections

3.2. Impacts on water treatment policies?

3.2.1. This leads to a need for improved methods when it comes to water treatment, in order to prevent the spread of ARGs

3.3. Need for alternative disinfection methods?

3.3.1. With chlorine disinfection treatments promoting the exchange of ARGs, there is now a need for exploration of other disinfection techniques to minimize the spread of ARGs.

4. Chlorine Disinfection

4.1. Purpose?

4.1.1. Chlorine disingection is used in water treatments to eliminate harmful pathogens and to ensure water safety and qualitity

4.2. Mechanism?

4.2.1. Chlorine forms hypochlorous acid in water, which penetrates bacterial cells and disrupts their membranes

4.3. Effects of bacterial cells?

4.3.1. Chlorine disinfection kills bacteria by damaging cell membranes and denaturing proteins. This process can release bacterial DNA and ARGs into the environment

4.3.1.1. When chlorine disrupts bacterial cell membranes, it induces catabolic reactions as the cell's components are broken down (Chapter 3- Catabolic reactions)

4.4. Stress response?

4.4.1. Chlorine-induced damage to bacterial cells triggers stress response pathways.

4.4.1.1. Signal proteins help bacteria detect and respond to oxidative stress, which is crucial for survival and adaptation (Chapter 4- Signal proteins)

4.5. Target of chlorine?

4.5.1. Chlorine damages cell membranes, leading to bacterial cell death by disrupting membrane integrity and causing leakage of cellular contents, including DNA and ARGs (Chapter 11)

5. Antibiotic Resistant Genes (ARGs)

5.1. Types of ARGs?

5.1.1. Some types of ARGs incluce genes that provide resistance to antibiotics like betalactams, tetracyclines, etc...

5.2. Spread of ARGs?

5.2.1. ARGs can spread through horizontal gene transfer mechanisms such as transformation, conjugation, and transduction

5.3. Impact on public health?

5.3.1. The spread of ARGs leads to the emergence of antiobiotic-resistant bacteria, complicating the treatment of infections

5.4. Immune response?

5.4.1. B cells produce antibodies that target and neutralize pathogens, including antibiotic-resistant bacteria. They play a crucial role in the body's defense against infections (Chapter 4)

5.5. Memory B cell?

5.5.1. Memroy B cells are cells that are able to remember specific pathogens, allowing for a quicker and more effective immune response if the same pathogen is encountered again (Chapter 4)

6. Natural transformation

6.1. Defintion?

6.1.1. Natural transformation is a process where bacteria takes up free DNA from their envrionment

6.2. Process?

6.2.1. Competent bacterial cells bind and incorporate DNA fragments into their genome

6.3. Role in horizontal gene transfer?

6.3.1. Natural transformation facilitates the spread of ARGs among bacterial populations

6.3.1.1. When bacteria takes up and incorporates ARGs into their genome, they undergo anabolic reactions to synthesize new proteins based on the acquired genes (Chapter 3- Anabolic reactions)

6.4. Competence development?

6.4.1. Signal proteins are involved in the development of bacterial competence, a state in which bacteria can take up external DNA (Chapter 4)

6.4.1.1. This process is regulated by a complex network of signaling pathways

6.5. DNA uptake?

6.5.1. In regards to natural transformation, bacteria needs an intact cell membrane to take up DNA from the environment. The cell membrane's permeability and receptor proteins facilitate the uptake of external DNA (Chapters 4 and 11)

7. Horizontal gene transfer

7.1. Definition?

7.1.1. Horizontal gene transfer can be defined as the movement of genetic material between organisms other than vertical transmission

7.2. Methods of horizontal gene transfer?

7.2.1. Transformation

7.2.1.1. This is the uptake of free DNA from the environment

7.2.2. Conjugation

7.2.2.1. This is the transfer of DNA through direct cell-to-cell contact

7.2.3. Transduction

7.2.3.1. This is the transfer of DNA by bacteriophages

7.3. Implications for antiobiotic resistance?

7.3.1. This implies that horizontal gene transfer promotes genetic diversity and adaptation, further enhancing the spread of antibiotic resistance

7.4. Regulation and facilitation?

7.4.1. Signal proteins can regulate the machinery involved in gene transfer. They ensure the appropriate conditions are met for processes like conjugation and transformation to occur efficiently (Chapter 4)

7.4.2. The cell membrane acts as a barrier to gene transfer, but it also contains proteins that facilitate processes like transformation and conjugation, which are crucial for horizontal gene transfer (Chapter 11)

8. Plasmids

8.1. Structure?

8.1.1. Plasmids are small, circular DNA molecules separate from chromosomal DNA

8.2. Role in carrying ARGs?

8.2.1. Plasmids can carry multiple ARGs, making them mobile genetic elements

8.3. Transfer mechanisms?

8.3.1. Plasmids can be transferred between bacteria via conjugation or transformation