Lecture Exam 3 Flashcards
Antibiotics
Antimicrobial agent that kills and interferes with the growth of microbes
Synthetic antibiotic
Not natural: made in the lab
Semi synthetic antibiotics
Natural product that is modified in the lab
Why was cantaloupe used to produce penicillin
It is cheep and easy to grow
- makes lots
Broad spectrum
Antibiotic works against many types of bacteria
Narrow spectrum
Antibiotic works only on a certain bacteria
Specific!!
Superinfection
Bacterial overgrowth
What causes a superinfection?
Disruption of a community
- overgrowth of a certain microbe
Magic bullet idea
Kill the bacteria w/o harking host cells
What is the technical term for “magic bullet”
Selective toxicity
Antimicrobial drugs
Kill or interfere with growth of microbes
Bacteriostatic
Reversibly stops bacteria from growing
- “static” like the tv is stuck
Bactericidal
Kills bacteria
- like suicide - kill oneself
What are the 5 mechanisms of action for Antimicrobial drugs ( inhibit what)
- Inhibit cell wall synthesis
- Inhibit protein synthesis (ribosome)
- Inhibit dna replication
- Injury the plasma membrane
- Inhibit metabolism
Transpeptidase
Enzyme that joins cross bridges on the cell wall
Penicillin
beta lactam ring = consistent part
Side chain = what makes them different (variable)
Competitive inhibitor
It competes w/ substrate to bind to active site
- able to bind to active site making it still a functional enzyme
Non competitive inhibitor
Binds outside of substrate- substrate still able to bind to active site
- makes it nonfunctional due to changing shape
Penicillin is a _______ inhibitor
Competitive
How does penicillin inhibit cell wall synthesis?
It inactivated transpeptidase, weakening the cell wall - resulting in the cell lyses (die)
What type of solution would the cell lyse in the presence of penicillin?
Hypotonic
Penicillinase
Breaks the beta-lactam ring of penicillin making the antibiotic not functional
What are the beta lactams we looked at?
- natural penicillin
Methicillin
Amoxicillin
Penicillin is most effective against
Gram positive : due to having difficult time getting through outer membrane of gram negative
Penicillin is a _______ spectrum
Narrow - work against gram positive only
Two semisynthetic penicillin
Methicillin & amoxicillin
Methicillin
Beta lactamase resistant - resistant against penicillinase
Amoxicillin
Fits through porins of gram negatives - can work against normal g+ / g-
Clavulanic acid
Non competitive penicillinase inhibitor
Amoxicillin with clavulanic acid
Allows it to inhibit cell wall synthesis of normal g+/g- and G+/G- w/ penicillinase present
Inhibitors of cell wall synthesis best kill
Only cells that are growing
Vancomycin
inhibits cell wall by binding to peptide chains & blocking transpeptidase activity
Vancomycin is _____ spectrum
Narrow
Mechanisms of inhibiting the ribosome
- blocks tRNA attachment
- Blocks the ability to form a peptide bond
- blocks translocation
- inhibits small & large subunits from interacting
- change shape of ribosome = change of function
Ribosome
Has large subunit - 50s
Small subunit - 30s w/ e site, p site, a site
What antibiotics target the ribosome
Chloramphenicol
Doxycycline
Streptomycin
Tobramycin
Azithromyosin
Linezolid
Doxyclycline
Long retention in the body
Streptomycin
Sometimes used for tuberculosis
Tobramycin is used for
Cystic fibrosis
Azithromycin is sometimes used for
Chlamydia
Linezolid is sometimes used against
MRSA
Antibiotics that target the ribosome are typically broad or narrow spectrum
Broad
What Antimicrobial drug inhibits rna synthesis
Rifampin
Rifampin is used to treat
Tuberculosis
Rifamycins antibiotic group
Inhibit mRNA synthesis by acting on bacterial rna polymerase
Rifampin directly inhibits…..
Transcription
What Antimicrobial drug inhibits dna synthesis
Fluoroquinolones
Fluoroquinolones antibiotic group
Inhibits bacterial DNA gyrase which can ultimately cause DNA breakage ( relieving tension in dna when dna is unwound during dna replication)
What 2 Antimicrobial drugs injure the plasma membrane
Polymyxin B
Daptomycin
Polymyxin
Inserts into membrane causing increased permeability (leaky cell)
- ## target more electronegative membranes
Polymyxin is effective against
Gram negatives only
Daptomycin
Insert into the membrane creating pores leading to leakiness
Daptomycin is effective against
Gram positive only
Antimicrobial drugs that inhibit metabolism
Sulfonamide
Trimethoprim
Sulfonamides (sulfa drugs)
Inhibits one step of folic acid synthesis
Trimethoprim
Inhibits another step of folic acid synthesis
Synergism
Effectiveness of 2 drugs is greater than one
Sulfonamides & trimethoprim are ______ inhibitors
Competitive
What are the 4 mechanisms of bacteria resistance to antibiotics
- Blocking entry
- Inactivating enzyme
- Altering molecule
- Efflux (kicking out) antibiotic
Superbug
Multi drug resistant bacteria
Example of a superbug
MRSA
What can staphylococcus aureus cause
Pimples
Pneumonia
Food poisoning
Infections caused by staphylococcus aureus
Skin and soft tissue
Breast implant infection
Endocarditis
Mutations that provide antibiotic resistance occur
Spontaneously
Natural selection
Passing down genetics
- surviving and reproducing
Mutations that allow an organism to survive/ reproduce are selected under certain selective pressure
True or False
True
Directional selection
Bacteria that are antibiotic resistance are able to survive and reproduce if treatment was stopped early
Advantageous mutations in bacteria can be passed how
Vertically and horizontally
What are the 3 ways horizontal gene transfer can occur
Transformation
Conjugation
Transduction
What are the 2 ways antibiotic resistant bacteria strains come about?
- overuse of antibiotics
- misuse of antibiotics
Overuse of antibiotics cases the high resistance bacteria to survive
True or False
True: ⬆️ antibiotic use = ⬆️ exposure of bacteria to antibiotic = ⬆️ likelihood antibiotic resistant bacteria will survive/ reproduce
What are some ways a person can misuse antibiotics
- used inappropriately (taking for their infections)
- treatment is not long enough
Treatment is too low of a dose
HAI - Hospital acquired infection
Infection patient gets while in the hospital
Hospital acquired infection is also known as
Nosocomial infection
CAI - community acquired infection
Infection acquired outside a healthcare facility
What three things should you consider with a hAI
Compromised hosts
Chain of transmission
Microbes present in healthcare - antibiotic resistant ones
Compromised hosts
Resistance to infection is impaired by disease, therapy or burns
- have suppressed immune system
What are some routes of transmission
Direct contact
Indirect contact
What a re some ways to prevent antibiotic resistant bacteria from spreading ?
- complete entire antibiotic dose
- do not use left over medication to treat other illness
- try to use narrow spectrum when possible
- don’t take it if it is not necessary
Pathology
The study of a disease and its…
Etiology
Cause of the disease ( the source)
Pathogenesis
How a disease develops ( structurally and functionally)
Epidemiology
Study of when and where diseases occur and how diseases are treated
- on population level
Infection
Body gets invaded by pathogen
Disease
Body (or parts of it)re in a abnormal state where it is incapable of preforming its normal function
Can you have an infection without it causing disease?
Yes!!
Symptoms
Changes that a patient feels or experiences
Ex. Dizziness or nausea
Signs
Changes a physician can physically see/ measure
Ex. Temperature, color,rash
Predisposing factors
A factor that makes an individual more susceptible to the disease and may change the diseases progression
What are the two disease classifications
Incidence & prevalence
Incidence
Number of people in a population that develop a disease during a specific time
- indicates spread of disease (only new cases)
Prevalence
Number of people in a population who have a disease at a specific time
- new/old cases
Sporadic disease
Occurs spontaneously
Endemic disease
Constantly present in a population
Ex, common cold
Epidemic disease
Many people in one area contract the disease in a short period of time
Pandemic disease
Epidemic disease that occurs worldwide
What are the 3 main themes of duration of a disease?
Chronic, substrate, acute
Acute means
It develops quickly
- lasts for a short period of time
Chronic means
It develops slowly
- likely to recur
Subacute means
It’s b/ chronic and acute
Latent disease
Causative agent remains dormant but then becomes active
Ex, chicken pox
What are some reservoirs of disease?
Humans, animals, water soil
Reservoir of infection
A continual source of infection
What are two common non living reservoirs?
Soil & water
Asymptomatic carriers
Harbor pathogen w/o showing signs of illness
Zoonotic disease
Vertebrate animal reservoirs
What are ways a person can contract a zoonotic disease?
By handling in Al waste, eating animal products or animal fur
What is the goal of. Pathogen when it infects a host?
Survive, reproduce and spread to more individuals
What are the 3 main mechanisms of transmission
Contact, vehicle & vector
What a re the 3 ways of contact transmission?
Direct, indirect and droplet
Direct contact
Physical contact b/w a source and susceptible host
Indirect contact
An agent is susceptible host indirectly such as a non living object
Fomite
Non living object that spreads infection
Droplet contact
Pathogen spreads via mucus droplets (droplet nuclei)
How far can pathogen droplets travel?
Less then 1 meter
Vehicle transmission
Transmission of disease agents by a medium
- what we need to survive!!!
What are some vehicle transmissions (think of essential things to live)
Food, water, air
How far can airborne disease travel?
More than 1 meter
What helps determine the distance a pathogen will travel?
Pathogen size/ shape
Vector transmission
Pathogen is carried in vectors usually by an arthropod
Vector
An organism that carries a pathogen from one host to another
What are the two types of vector transmission?
Mechanical & biological
Vector via mechanical transmission
Arthropod carries pathogen accidentally on feet
Ex. Houseflies
Vector biological transmission
Pathogen reproduces in vector and is passed via bitting
Ex. Mosquito
When a MRSA is transmitted on a stethoscope from one patient to the next this is an example of what type of transmission?
Indirect contact transmission
When salmonella is ingested by eating contaminated food, this is an example of what type of transmission?
Vehicle transmission
When plasmodium is transmitted to a human host from a mosquito bite this is an example of what type of transmission?
Vector biological transmission
What’s a diseases impact on a community?
- it impacts the community and the community impacts the spread of a disease, how it develops
Why was it/ is difficult to study a virus?
- they are really small
- they require a host in order to survive
Viruses structure (what they include)
Nuclei acid
DNA/RNA
Protein coat (capsid)
Sometimes: Few proteins
Lipid bilayer - Envelope
Virion
Single, mature, infective final particle
Capsid
Protein coat that surrounds nuclei acid
Capsomere
Protein subunit that makes up capsid
- maybe one/ multiple protein types
What a re the different capsid types
Helical
Polyhedral
Complex
Helical capsid
Hollow rods
-flexible/ rigid
Polyhedral capsid
(Found in animals)
- has many sides
Complex capsid
(Looks like spaceship)
Can have multiple capsids
- variable shape
An envelope
Lipid layer that covers capsids
- can contain proteins/carbohydrates
Glycoprotein spikes purpose
Help attach to host cells
Viruses without a envelope are called
Non enveloped viruses
What are the two main cycle sin bacteriophage replication?
Lyric cycle
Lysogenic cycle
Lyric cycle
Culminates in host cell death
What are the 5 steps of the lyric cycle?
Attachment
Penetration
Biosynthesis
Maturation
Release
Attachment of lytic cycle
Tail fibers help virus to attach to host cell
Penetration of lytic cycle
Drives core through allowing sheath to inject genetic info
Biosynthesis of lytic cycle
DNA replication
RNA created via transcription/ translation
- host dna degraded = virus uses host to replicate
Maturation lytic cycle
DNA & proteins self assemble creating virions
- build up new viruses
Release lytic cycle
Host cell lyses and new viruses released
Lysogenic cycle
Host cell survives
- viral dna being integrated into host
Prophage
Page dna inserted in to genome
What happens during the Lysogenic cycle
Virus attaches releasing dna letting it get integrated (prophage) into host enzyme allowing it to reproduce creating more
Transduction
-type of horizontal gene transfer
Bacterial dna is packaged/ integrated into the virus instead of viral dna
Animal virus replication steps
- Attachment
- Entry
- Uncoating
- Biosynthesis
- Maturation
- Release
Animal virus replication : attachment
Complementary receptor attachment
- host range driven by protein = receptor interacting
Animal virus replication: entry
2 ways ; receptor mediated endocytosis & fusion
Entry via receptor mediated endocytosis
Virus bound to protein on plasma membrane and brought in by membrane folding
Entry via fusion
Viral envelope fuses plasma membrane and releases the capsid into the cells cytoplasm
Animal viruses replication: uncoating
Viral nuclei acid separated from protein coat
Animal viruses replication: biosynthesis
Synthesis of nucleic acids/ proteins
- creates more phage dna using host machinery
Animal virus replication: maturation
Capsid is assembled around genetic info
Animal virus replication: release
Can be either via budding or rupture
Rupture release
Host plasma membrane is broken apart as virus releases
- host cell usually killed
Budding release
Host plasma membrane surrounds virus and pinches off forming an envelope
Plaques means
A clearing in a bacterial lawn resulting from lysis by phages
What are the different phases of disease?
- Incubation period
- Prodromal period
- Period of illness
- Period of decline
- Period of convalescence
Incubation period
Time b/w infection and signs/symptoms
Prodromal period
Mild, general symptoms (1st few days)
Hard to distinguish b/w common cold & other diseases
Period of illness
Most severe signs/symptoms
Where immune system is actively fighting off pathogen
Period of decline
Immune system is ‘wining”
- signs/symptoms decreasing
(Pathogen present = declining)
Period of convalescence
Recovery time, where individual is regaining strength
- body returns to normal
True or False
You can be contagious during all phases of disease
True
Pathogenicity
Ability of a microorganism to cause disease by overcoming the defenses of the host
Virulence
The degree of pathogenicity of a microb
Virulence factor
Specific proteins that help a microbe establish disease
What are some portals of entry for a microorganisms?
Mucus membranes
Skin
Parental route
Why do bacteria have a preferred portal of entry?
Depending on certain entry will either cause disease or no disease
More microbes that invade makes it harder for the immune system to fight
True or False
True
ID50
Infectious dose
- needs to infect 50% of population
LD50
Lethal dose
- needs to kill 50% of the population
Measurements ID50 & LD50 describe
- virulence of bacteria or specific strain
- preferred portal of entry
- # of invading microbes needed to establish disease
Adherence
Microbe attaching to plasma membrane
Are adherence be pathogenic or non pathogenic
Both!
Adhesion (ligand)
Microbial factor that promotes attachment to receptor
What are ways bacteria can hide from the immune system?
Capsule
Extracellular enzyme
- coagulase / igA proteais
Antigenic variation
Type 2 secretion system
A capsule is best described as a _____ glycocalyx
Organized
Capsules
Prevent phagocytic cells from engulfing and killing bacteria
Extracellular enzymes
(Exoenzymes) enzymes that work outside the cell
Coagulase
Converts fibrinogen into fibrin
- binding fibrin making it resist phagocytosis
IgA proteasis
Destroying igA antibodies
- goes in a cuts them
Antigenic variation
Alters surface of an antigen
- LIKE A DISGUISE !
Pathogen changes antigen to be unrecognizable
How are antigens recognized?
Antigens = surface marker on microbe
Antibody = made from host, who recognizes antigen
Influenza virus can have antigenic variation
True or False
True: varies each year
Type two secretion system
(Protein “syringes” found in gram- )
- inject effectors into host to make it easier to infect
Two ways t cause damage to host cells
Siderophores & toxins
Siderophores
Proteins that bind iron (often taken from host)
Toxins
Poisonous substances made by certain microorganisms
What are the 2 types of toxins?
Endotoxin
Exotoxin
Exotoxin
Produced inside bacteria and then released
3 types of an exotoxin
A-b
Membrane disturbing
Superantigen
Endotoxin
Part of pathogen (the cell wall of g-)
Endotoxin a means
Active - effects cells function
Endotoxin B means
Binding part - binds to host receptor allowing toxin into host
Endotoxin membrane disturbing
Disrupts cell membrane & cell lysis occurs
Ex. Lipids
What a re some portals of exit for microbes?
Mucus membranes
Skin
Blood
Convolution
The influence of closely associated species on each other in their evaluation