Topic 1-5 (Lecture 5) Flashcards
What has the most impact on bacterial disease prevention?
Sanitation and Education
What are ancient/modern methods of sanitation?
- slightly alcoholic beverages, having settlements near streams
- Using natural preservation methods to keep food good (ex. spices, salt and vinegar, dehydration)
- Getting fresh air
- Dental and hand hygiene
- Quarantine
What is an example of quarantining?
Sanatoriums for disease like TB or Leprosy (isolation of contagious individuals for treatment)
What is the main goal of education (for disease)
Inform the public on behavioral adaptations that can decrease risk/spread of bacteria
Why is education good?
-It’s cost-effective
What are the 2 levels that education can work at?
Personal - ex. teeth-brushing, hand sanitizer use, etc.
Political - building adequate sanitation systems
What are bacteriophages?
Viral agents that recognize and lyse bacterial pathogens
What are pros to using bacterophages?
Chepaer to make than antibiotics
Mutations can be beneficial
What are cons to using bacterophages?
Mutations can be detrimental/make viruses unsuitable for therapy
Research costs are the same in terms of cost when compared to antibiotic research
What are the 2 traits that are desirable in bacterophages?
Specificity - only targets bacteria that is causing problems (shouldn’t disrupt microbiota that much)
Lysis - Viruses that are lytic are desired (can be lytic (killing) or lysogenic (not killing))
What are antiseptics?
Chemical agents that are applied to LIVING tissue to kill or inhibit the growth of microorganisms
What are disinfectants?
Chemical agents used on INANIMATE objects to kill microorganisms
What is the difference between antiseptics and disinfectants?
One is for living tissue (antiseptics), on is for inanimate objects (disinfectants)
What are chemotherapeutic agents?
Chemical agents used to control infectious diseases internally in a body
What are chemotherapeutic agents that work on bacteria called?
Antibiotics
What are the two types of antibiotics?
Bactericidal
Bacteriostatic
What do bactericidal antibiotics do?
KILL bacteria
What do bacteriostatic antibiotics do?
INHIBIT bacterial growth
What is the difference between natural, semi-synthetic and synthetic antibioitics?
Natural - come from natural sources (ex. mold)
Semi-synthetic - chemically modified natural antibiotics (such that it isn’t “natural”)
Synthetic - What it means
What is usually more sensitive to antibiotics: Gram-positive or gram-negative?
Gram positive
What are the two “spectrums” of antibiotics?
Broad and narrow spectrum
What is the difference between broad and narrow spectrum antibiotics?
Broad acts on both gram +ve and gram -ve bacteria, whereas narrow spectrum antibiotics only act on a single group of organisms
What are optimal attributes of chemotherapeutic agents?
Soluble in body fluids w/ good penetration to infection site
A broad spectrum of activity (i.e. activity against broad range of bacteria)
Low frequency of resistance development
Low rate of breakdown in body
Low toicity
Well-tolerated in human body
Non-allergenic
What are some ways how antibiotics work?
1) Interfere w/ bacterial cell wall biosynthesis by inhibiting peptidoglycan (only bacteria have this)
2) Destabilize cell membrane (potentially dangerous/toxic to humans, last resort)
3) interfere w/ protein synthesis by binding to ribosome and inhibiting function (doesn’t affect humans due to difference in eukaryote ribosomes)
4) interfere w/ DNA gyrase activity, disrupting replication (different in bacteria vs eukaryote)
5) interfere w/ DNA-directed RNA polymerase activity (bacterial RNAPol is different enough from humans to be OK)
6) Interfere w/ folic acid metabolism (bacteria-specific metabolic processes)
What is antibiotic resistance?
Acquired ability of microorganisms to resist the effects of an antibiotic which it is normally sensitive to
What is vertical gene transfer?
Transfer of mutations (ex. antibiotic resistance) to offspring during mitosis
What are the three mechanisms of horizontal gene transfer?
Conjugation
Transduction
transformation
What is conjugation (horizontal gene transfer)?
Transfer of plasmid DNA via cell-cell contact
What is transduction (horizontal gene transfer)?
Bacterial virus picks up DNA from resistant bacteria and transfers it to sensitive cell (can be plasmid or chromosomal DNA)
What is transformation (horizontal gene transfer)?
DNA w/ resistance gene taken from environment
Are all resistance traits from mutation?
No, some bacteria is natural resistant (ex. lack the structural target of antibiotic; have natural physiological features such as pumps that diminish antibiotic effects)
Why does exposure to antibiotics can result in resistant bacteria?
Antibiotics apply a population pressure that selects for resistant bacteria to thrive (think ecology). It is NOT exposure that results in resistance
What are problems with antibiotics now?
They are overused
- Antibiotics used for wrong illnesses (incorrect prescription or too acessible)
- People don’t complete antibiotic course -> less-than-lethal exposure promotes antibiotic resistance to develop
- Antibiotic misuse in agriculture (potential for zoonosis)
What are some consequences of antibiotic use?
- One may experience side-effects
- Microbiota may also be affected (could lead to opportunistic pathogens to infect)
*Microbiota usually re-establish itself after finishing antibiotic course
What is the problem with superbugs?
We cannot use antibiotics as effectively against them (the current ones) due to resistance, and developing new antibiotics are expensive
How do biofilms contribute to antimicrobial resistance?
1) EPS matrix impede penetration of anitmicrobial agents
2) O2 and nutrient gradient results in some cells being less metabolically active -> metabolically active bacteria are more affected by antibiotics; thus less metabolically active = less affected by antibiotics
3) Persister cells just stay alive for some reason - hard to kill
Approaches to anti-biofilm therapy?
1) Interfere w/ EPS
2) Interfere w/ biofilms from forming
3) Target autoinducers - no autoinducers, no signal; no signal, no quorum sensing and thus no biofilm formation
How do vaccines prevent disease? *Review
Prevent disease by training a secondary immune response
What materials are used to make vaccines?
- killed virulent bacteria
- avirulent mutants of pathogenic bacteria
- outermost components of microoganisms
- toxoids (toxins that have been deactivated)
What are the 2 forms of immunity? *Review
Active and passive
What is the difference between active and passive immunization? *Review
Active immunization relies on induction of immune response (trained response); passive immunization relies on injecting pre-formed antibodies (cannot train response)
