6. Antimicrobial Drugs and Resistance Flashcards
How do vaccines work?
they prime the immune system by stimulating primary immune responses (in the graph it’s the first hump)
Vaccine goals
- It shouldn’t cause disease
- the goal is the production of memory cells that can be activated if ever the pathogenic material is encountered at a later time.
How are vaccines beneficial
- protect against viral infections
- since viruses can’t be eliminated with chemotherapy, prevention makes the most sense
Are vaccines equal in risk
no
Categories of vaccines
- live attenuated
- whole agent inactivated
- subunit vaccines
- toxoid vaccines
- conjugated vaccines
Live attenauted vaccines - what, safeness, stimulates
- WHAT: live virus thats weak
- accomplished by key mutation
- still maintains many of the properties of the wild-type pathogen (virus can still ADSORB and penetrate but cannot replicate)
- STIMULATES: Stimulates both antibody and cell mediated immunity
- SAFENESS: can spontaneously mutate back to wild-type (potential to cause disease)
Examples of live attenauted vaccines
Sabin vaccine against Poliovirus, Rotavirus vaccine,
MMRV vaccine (Measles, Mumps, Rubella, Varicella), some Rabies
vaccines, vaccine against Mycobacterium tuberculosis
Whole agent inactivated vaccines - what, safeness, stimulates
- WHAT: not alive (inactivated virus)
- incapable of adsorption or penetration (can’t get in)
- SAFNESS: no risk of causing disease
- STIMULATES: only stimulates antibody mediated immunity - so you need boosters
Example of whole agent inactivate vaccines
Hepatitis B vaccination, the flu
shot, Rabies vaccine used in humans, Salk vaccine
for Poliovirus
Subunit vaccines - what, safeness, stimulates
- WHAT: include purified proteins (antigens) taken from pathogenic bacteria and virus
- SAFENESS: doesn’t contain ANY infectious material - very safe
- STIMULATES: only stimulates antibody mediated immunity
Example of subunit vaccines
Hepatitis A vaccination, Human Papilloma Virus Vaccine,
pneumoshot (contains purified capsule from Streptococcus pneumoniae),
meningococcal vaccine (contains purified capsule from Neisseria
meningitidis)
Toxoid vaccines - what, safeness, stimulates
- WHAT: inactivate toxin that consists of bacterial toxins that have been modifies
- maintain the same properties of the actual toxin
- SAFENESS: toxoid is incapable of causing the same effects as the toxin - very safe
- STIMULATES: only stimulate antibody mediated immunity, often provide short-lived protection so you need booster shots
Example of toxoid vaccines
DTaP vaccine against diptheria toxin, tetanus toxin,
and pertussis toxin
conjugates vaccines
- WHAT: antigens that have been conjugated together
- increases the overall size of the antigen
- addresses limitations of naive adaptive immune system in children
- increases immunogenicity = better protection
Examples of conjugated vaccines
polysaccharide vaccine against
capsule of Haemophilus influenzae conjugated to
protein
antimicrobial drugs - what is it and when do we use it
drugs that are effective against microorganisms
- used when immunization has not occurred and the immune system has difficulty to eliminate infection
- useful against bacterial infection , very few antivirals are available
- these are compounds that kill or control the growth of microorganisms in the host (these drugs must display selective toxicity or they will cause damage to the host)
3 categories of antimicrobial drugs
- synthetic or natural - large number of naturally occuring antibiotics with no clinical use - produced by bacteria and fungi
- bacteriostatic or bactericidal
- broad or narrow spectrum
Example of antibiotic targets
cell wall synthesis, DNA gyrase, RNA elongation, DNA-directed RNA polymeras, protein synthesis (50S or 30S inhibitors, RNA), lipid biosynthesis, cytoplasmic membrane structure and function, folic acid metabolism
beta lactam antibiotics - where, what, cons
WHERE: naturally occurring produced by penicillium and cephalosporium fungi
WHAT: can be modified in the lab to produce semi-synthetic drugs that have a modified spectrum of activity
CONS: susceptible to beta-lactamases (enzyme produced by some bugs to cut and inactivate beta-lactams
Penicillins - call wall antimicrobial drugs - spectrum, structure, defining ft
- narrow spectrum
- five membered ring attached to the beta-lactam component
- target transpeptidation in gram positive bacteria
- cannot penetrate outer membrane of gram negative bacteria (semi-synthetic penicillin are modified to provide some activity against gram negative bugs - ampicillin)
Cephalosporins - cell wall antimicrobial drugs - spectrum, structure, defining ft
- broader spectrum
- six membered ring attached to beta-lactam component
- target transpeptidation in peptidogylcan
- semi-synthetic
- better resistance against beta lactamases
- grouped into generations (1st gen, 2nd gen)
sulfa drugs
- ex) sulfanilamide
- inhibit growth of bacteria by inhibiting folic acid synthesis and nucleic acid synthesis
- often used in combination with another analog - trimethoprim (combination therapy minimizes the likelihood of resistance)
nucleic acid synthesis inhibitors types
- quinolones
- rifampin
- actinomycin
aminoglycosides - spectrum, bind, defining features
- BIND: 30s subunit of 70 ribosomes
- SPECTRUM: narrow - useful against gram negativebugs
- WHAT: block translation
- often used as a last resort
- damaging to kidneys and ears
tetracycline - spectrum, bind, defining ft
SPECTRUM: broad
BIND: 30s subunit
WHAT: consist of both natural and modified semisynthetic drugs
- binds to calcium damaging teeth and bone - shouldn’t be used by children and pregnant women
- used in vet med to promote animal growth
macrolides - binding, spectrum, defining ft
SPECTRUM: broad
BIND: 50s ribosomal subinit
WHAT:
- only inhibits translation of some proteins
- some proteins are preferential translated and others are not
- creates a detrimental protein imbalance inside of the cell
- useful to treat infection in patients with allergies to beta lactam antibiotics
ways of antibiotic resistance
patterns of antibiotic/antimicrobial resistance
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