L24 antibiotics and resistance
Page 3: Keanumycins
Discovery of new NRLPs (Natural Resistant-Like Peptides) that are highly effective against various microbial species.
Named "keanumycins" in honor of actor Keanu Reeves for his roles as iconic killers in films.
Newly discovered compounds have potential applications in agriculture and medicine, particularly as anti-fungal agents.
The discovery is reported by Götze et al. (2023) in the Journal of the American Chemical Society.
Page 4: Antibiotics, Selection, and Resistance
Effects of Antibiotics
Good: Help reduce bacterial infections.
Bad: Promote resistance leading to more resistant infections.
Good Bacterial Flora:
Bifidobacteria: Regulate gut bacteria, immune response, and vitamin production.
Escherichia coli: Some strains are beneficial for vitamin K production, but pathogenic strains can cause illness.
Lactobacilli: Help in immunity and nutrient production, protecting against carcinogens.
Pathogenic Bacteria:
Campylobacter: Causes foodborne illness.
Enterococcus faecalis: Associated with post-surgical infections.
Clostridium difficile: Can proliferate after antibiotic treatment.
Page 5: Common Bacterial Infections
Common infections include strep throat, pneumonia, food poisoning (salmonella, E. coli), sexually transmitted diseases (chlamydia, syphilis), skin infections (staphylococcus), and ear infections.
Page 6: Historical Bacterial Infections
Historical evidence shows individuals like Ötzi had bacteria causing Lyme disease and stomach ulcers.
Indications that bacterial infections have afflicted humans for over 5300 years.
Page 7: Evolution of Bacterial Infections
Evidence of brucella bacteria in ancient skeletons, indicating bacterial infections date back 1.5 to 2.5 million years.
Page 8: Dangers of Bacterial Infections
Plague (~1350 AD): Killed 30-60% of Europe’s population.
Infection risk data from 1935 shows much higher mortality rates due to bacterial infections in the past.
Page 9: Improvement in Survival
Significant improvements in survival rates due to the introduction of antibiotics in the 1940s, alongside vaccines and hygiene practices.
Page 10: Introduction of Penicillin
Discovered in 1928 by Alexander Fleming and widely used from the 1940s, marking the beginning of the antibiotic era.
Known as a “miracle drug” for its effectiveness in killing bacteria.
Page 11: The Golden Age of Antibiotic Discovery
Following penicillin, numerous new antibiotics were discovered from 1920 to 2020:
1920s: Glycopeptides
1930s: Ansamycins
1940s: Tetracyclines
1950s: Macrolides
1960s: Aminoglycosides
2000s onward: New synthetic and natural antibiotics like Oxazolidinones, which target various strains.
Page 12: From Awareness to Fear
Shift in perception regarding bacterial infections from awareness to fear, emphasizing the sophistication of microbial threats.
Page 13: Antimicrobial Products
Overview of antimicrobial products including the equivalent of Softsoap, which contains antibacterial agents effective in reducing germs.
Trends in mortality rates from infectious diseases over the years illustrated through data.
Page 14: Widespread Use of Antibiotics
Discussing the implications and realities of the widespread use of antibiotics in healthcare.
Page 15: Consequences of Antibiotic Overuse
Exploration of negative effects resulting from the overprescription and overuse of antibiotics in treating infections.
Page 16: Frontline on Antibiotic Resistance
Reference to a PBS documentary on antibiotic resistance, showcasing the dangers posed by resistant strains of bacteria.
Page 17: Antibiotic Resistance vs. Cancer Resistance
Comparison of the mechanisms behind antibiotic resistance in bacteria versus resistance mechanisms in cancer treatments and chemotherapy.
Page 18: Understanding Antibiotic Resistance
An overview of what antibiotic resistance entails and its rising significance in public health.
Page 19: MRSA (Methicillin-resistant Staphylococcus aureus)
Introduction to MRSA and its implications for infection control and treatment.
Page 20: Characteristics of Staphylococcus aureus
Commonly carried by 30% of humans, found on skin/nasal area.
Not always harmful, yet certain strains lead to severe infections.
Page 21: Warnings from Alexander Fleming
Quote from Alexander Fleming about the dangers of under-dosing antibiotics and the resulting resistance.
Page 22: The Rise of Methicillin Resistance
Initially, penicillin was curative until 40% of strains became resistant by the 1950s.
Methicillin was introduced in 1960, but MRSA prevalence surged in the 1990s.
Page 23: The Race Against Bacterial Resistance
Tracking antibiotic drugs approved by the FDA over time and the timeline showing introduced bacteria that have become resistant.
Page 24: Mechanisms of Antibiotic Resistance
Overview of how antibiotics work and how bacteria develop resistance.
Specific structures and essential components targeted by antibiotics include the cell wall and ribosomes.
Page 25: Penicillin Mode of Action
Explanation of how penicillin disrupts bacterial cell wall synthesis, leading to cell death due to osmotic pressure.
Page 26: Measuring Antibiotic Resistance
Methodology for determining bacterial resistance by assessing growth (halo) around antibiotic disc sources.
Page 27: Resistant vs. Sensitive Strains
Comparison of sensitivity and resistance in bacterial strains when exposed to various antibiotics.
Page 28: Mechanisms of Antibiotic Resistance
Various strategies bacteria employ to resist antibiotics include pumping drugs out, modifying targets, or inactivating the drug.
Page 29: Antibiotic Resistance in Bacterial Populations
Resistance mechanisms exist due to rapid reproduction, large populations, and existing mutations.
Horizontal gene transfer allows shared resistance traits among different bacterial species.
Page 30: Understanding Natural Selection in Bacteria
Natural selection illustrates how certain traits become prevalent in a population over time; variations are crucial.
Page 31: The Process of Natural Selection
Explanation of natural selection's components: variation within a population, inheritance of traits, differential reproduction, and gradual accumulation of successful traits.
Page 32: Practical Example of Natural Selection
Example illustrating the selection process with the shift in moth color due to environmental changes.
Page 33: Standing Variation in Populations
Natural selection acts upon existing variations in populations affecting survival and reproduction rates over generations.
Page 34: Phenotype Concentrations in Populations
Discussion around how various traits are represented in populations and how non-random survival can alter frequency.
Page 35: Cases of Directional Selection
Dark- vs. light-colored moths in response to environmental pollution as a case of directional selection.
Page 36: Understanding Stabilizing Selection
Describes stabilizing selection as seen in human births where certain weight ranges are favored for survival.
Page 37: Gene Pool Dynamics
Definition of gene pool and allele frequencies contributing to phenotype frequencies in a population.
Page 38: Evolution and Selection Relationships
Summary of how selection drives evolutionary processes across species, contrasting with bacterial resistance mechanisms.
Page 39: Mechanisms of Bacterial Resistance Development
Describes the processes through which bacteria can deal with antibiotics, notably through genetic exchanges and mutation.
Page 40: Plasmids and Resistance Genes
Explanation of plasmids as mechanisms for antibiotic resistance transmission among bacteria, highlighting their replicative functions.
Page 41: Bacterial Mating and Plasmid Transfer
Overview of how plasmids can be transferred via bacterial mating, emphasizing their roles in resistance.
Page 42: Antibiotic Evolution and Resistance Dynamics
Discusses the complexity of resistance development in bacteria through natural antibiotic production and gene transfer.
Page 43: Environmental Factors in Resistance Spread
Overview of how human activity and environmental bacteria can propagate resistance genes across populations.
Page 44: Biological Costs of Resistance
Comparison of how environmental factors influence resistance in both pathogens and commensals.
Page 45: Impact of Pollution on Resistance
Reflection on how pollution from human activity can enhance resistance gene spreading among bacteria.