an antimicrobial that is effective against a limited array of microbial types is called a _____ spectrum drug
narrow spectrum
what is drug resistance
when microbes begin to tolerate an antimicrobial agent at a level which would normally be inhibitory
an enzyme secreted by certain bacteria that cleaves the beta-lactam ring of penicillin and cephalosporin and thus provides for resistance against the antibiotic
- penicillinase
- beta-lactamase
laboratory-modified drug that originated and isolated from a natural source
semisynthetic drug
antimicrobial drug that is chemically synthesized in the lab (produced entirely by chemical reactions)
synthetic drug
particular microorganism produces a substance that kills another microorganism in its environment
antagonism
minimum inhibitory concentration
highest dilution of a drug where it visibly inhibits growth of a particular microorganism
lowest concentration of a drug that visibly inhibits growth
minimum inhibitory concentration (MIC)
VRSA
VRA
CDIFF
vancomycin-resistant staphylococcus aureus- concerning
vancomycin-resistant enterococcus- serious
clostridium difficile- urgent
all inclusive term for any drug used to fight an infection, regardless of its origin
antimicrobial
under which circumstance might a microbe be intrinsically resistant to an antibiotic
- when the microbe produces the antibiotic
- when the microbe does not have the molecular target of the antibiotic
bacteria that slow or stop their metabolism so that they cannot be harmed by an antibiotic are
persisters
when antibiotic resistance is a fixed trait of a microbe it is termed
intrinsic resistance
small RNA that binds a genetic sequence to silence a gene. can provide temporary resistance to the antibiotic
interfering RNA
R factor is a type of ___ that confers antibiotic resistance
plasmid
process of environment placing pressure on organisms to adapt and survive changing conditions
natural selection
post antibiotic era
a situation in which some infections will be untreatable to others
C. diff is an urgent hazard because
it causes disease when patients have been treated with multiple antibiotics
CRISPR has been used to treat antibiotic resistant infections by directing specific gene cuts to
the antibiotic resistance genes
preparations of live microbes used as a preventative or therapeutic measure to displace or compete with potential pathogens
probiotics
nutrients used to stimulate the growth of favorable biota in the intestine
prebiotics
enzyme that hydrolyzes penicillin and is found in penicillin-resistant strains of bacteria
penicillinase
use of chemotheraputic drugs to control infection and diseases caused by many types of microorganisms
antimicrobial chemotherapy
use of a drug to prevent imminent infection of a person at risk
prophylaxis
genus of fungi that is NOT a major source of antibiotics
aspergillus
essential to perform an antimicrobial susceptibility test for all infectious agents
false
antimicrobial (substance) produced by natural metabolic processes of some microorganisms that can inhibit or kill other microorganisms (term used for drugs targeting bacteria and not other types of microbes)
antibiotic
advantage of E test over kirby-bauer testing is that E test
provides the MIC for the drug
drugs that work for viral infections will target the virus in which of the following ways
- do not allow the virus to reproduce inside the cell
- prevents the assembly of new virus particles
- prevents entry if the virus into host cells
three major modes of activation of antiviral drugs
- barring virus penetration into host cells
- blocking virus transcription and translation
- preventing virus maturation
all inclusive term for any drug used tonight an infection, regardless of its origin type
antimicrobial
drugs that are effective against fungi have a strong possibility of being toxic to humans because both organisms are eukaryotes
true
primary sites for action of antimicrobial drugs in bacteria
- cell wall
- ribosomes
- nucleic acids
- cell membrane
drug resistance arises when an organism
- spontaneous mutation occurs in the organisms DNA code
- gains the genetic information for resistance from another organisms (acquisition of new genes)
normal ___ are beneficial or harmless resident bacteria commonly found on and/or in the human body
biota
drug reaction that occurs because the drug stimulates the immune system
allergy
when an infection is caused by an over-growth of a drug resistant microorganism during antimicrobial therapy
superinfection
when an allergic reaction to antigen develops rapidly and can result in shock and death this is referred to as
anaphylaxis
drug that is isolated from natural sources and then modified in the lab
semisynthetic
mechanisms of drug resistance
- new enzymes are synthesized, inactivating the drug (acquisition of new genes)
- permeability into bacteria is decreased (mutation)
- drug is eliminated (acquisition of new genes)
- binding sites are decreased (mutation OR acquisition of new genes)
- metabolic pathway is shut down (mutation)
epigenetic event
reversible mechanism that allows fungi to express certain genes targeted by antibiotics AFTER the antibiotics are no longer present
epimutation
genes are silenced and target of antibiotic is not manufactured by the fungus making it TEMPORARILY resistant to that drug
mechanisms of drug action
- inhibition of cell wall synthesis
- inhibition of nucleic acid (RNA and DNA) structure and function
- inhibition of protein synthesis
- interference with cytoplasmic membrane structure or function
- inhibition of folic acid synthesis
3 factors needed before antimicrobial therapy can begin
- identity of microorganism causing infection
- degree of microorganisms susceptibility to various drugs
- overall medical condition of patient
categories of major drug side effects
- toxic damage to tissue
- allergic reactions
- normal flora disruption
horizontal gene transfers occur through
- conjugation
- transformation
- transduction
antimicrobial drug damage
can be permanent or reversible
drug resistance genes found on ____ usually result from spontaneous random mutation
bacterial chromosome