lOMoARcPSD|11700591
Antimicrobials-
Used to treat infectious diseases
190 million doses of antibiotics are given in hospitals each day
Modern antimicrobials: 1930s and 1940s
Significantly reduced morbidity and mortality from infection
Basic Principles of Antimicrobial Therapy
Antibiotic
o Strictly speaking, a chemical produced by one microbe that can harm other
microbes
Antimicrobial agent
o Any agent that can kill or suppress microorganisms
Selective Toxicity-
Toxic to microbes but harmless to host
Differences in the cellular chemistry of mammals and microbes
Disruption of bacterial protein synthesis and cell wall
Inhibition of an enzyme unique to bacteria
Classification of Antimicrobial Drugs-
Various classification systems
The two used for this textbook:
o Classification by susceptible organism
o Classification by mechanism of action
Prophylactic Use of Antimicrobials-
Agents are given to prevent infection rather than to treat an established infection:
o Surgery
o Bacterial endocarditis
o Neutropenia
o Other indications
Misuses of Antimicrobial Drugs
Attempted treatment of viral infections
Treatment of fever of unknown origin
Improper dosage
Treatment in the absence of adequate bacteriologic information
Omission of surgical drainage
Monitoring of Antimicrobial Therapy
Monitor clinical responses and laboratory results
Frequency of monitoring should increase with severity of infection
Clinical indicators of success
, lOMoARcPSD|11700591
o Reduction of fever, resolution of signs/symptoms related to the affected organ
Serum drug levels for toxicity
Classification of Antibiotics-
Drugs work on:
Cell wall synthesis
Cell membrane permeability
Protein synthesis (lethal)
Nonlethal inhibitors of protein synthesis
Synthesis of nucleic acids
Antimetabolites
Viral enzyme inhibitors
Classification of Antibiotics (Cont.)-
Bacteriocidal
Drugs are directly lethal to bacteria at clinically achievable concentrations
Bacteriostatic
Drugs can slow bacterial growth but do not cause cell death
Dosage Size and Duration-
Antibiotic must be present:
o At the site of infection
o For a sufficient length of time
Antibiotics must not be discontinued prematurely
Teach patients to complete full prescription
Antibiotic Combinations-
Antimicrobial effects of antibiotic combinations
o Additive, potentiative, antagonistic
Indications
o Mixed infections, prevention of resistance, decreased toxicity, enhanced
bacterial action
Disadvantages of combinations
Penicillins (Cont.)
Action- Weaken the call wall of bacteria.
Resistance- Is determined by inability to reach the target, inactivation by bacterial
enzymes and production of penicillin binding proteins that have a low affinity for it.
Active against a variety of bacteria
Direct toxicity: Low
Principal adverse effect: Allergic reaction
Structure includes a beta-lactam ring
Antimicrobials-
Used to treat infectious diseases
190 million doses of antibiotics are given in hospitals each day
Modern antimicrobials: 1930s and 1940s
Significantly reduced morbidity and mortality from infection
Basic Principles of Antimicrobial Therapy
Antibiotic
o Strictly speaking, a chemical produced by one microbe that can harm other
microbes
Antimicrobial agent
o Any agent that can kill or suppress microorganisms
Selective Toxicity-
Toxic to microbes but harmless to host
Differences in the cellular chemistry of mammals and microbes
Disruption of bacterial protein synthesis and cell wall
Inhibition of an enzyme unique to bacteria
Classification of Antimicrobial Drugs-
Various classification systems
The two used for this textbook:
o Classification by susceptible organism
o Classification by mechanism of action
Prophylactic Use of Antimicrobials-
Agents are given to prevent infection rather than to treat an established infection:
o Surgery
o Bacterial endocarditis
o Neutropenia
o Other indications
Misuses of Antimicrobial Drugs
Attempted treatment of viral infections
Treatment of fever of unknown origin
Improper dosage
Treatment in the absence of adequate bacteriologic information
Omission of surgical drainage
Monitoring of Antimicrobial Therapy
Monitor clinical responses and laboratory results
Frequency of monitoring should increase with severity of infection
Clinical indicators of success
, lOMoARcPSD|11700591
o Reduction of fever, resolution of signs/symptoms related to the affected organ
Serum drug levels for toxicity
Classification of Antibiotics-
Drugs work on:
Cell wall synthesis
Cell membrane permeability
Protein synthesis (lethal)
Nonlethal inhibitors of protein synthesis
Synthesis of nucleic acids
Antimetabolites
Viral enzyme inhibitors
Classification of Antibiotics (Cont.)-
Bacteriocidal
Drugs are directly lethal to bacteria at clinically achievable concentrations
Bacteriostatic
Drugs can slow bacterial growth but do not cause cell death
Dosage Size and Duration-
Antibiotic must be present:
o At the site of infection
o For a sufficient length of time
Antibiotics must not be discontinued prematurely
Teach patients to complete full prescription
Antibiotic Combinations-
Antimicrobial effects of antibiotic combinations
o Additive, potentiative, antagonistic
Indications
o Mixed infections, prevention of resistance, decreased toxicity, enhanced
bacterial action
Disadvantages of combinations
Penicillins (Cont.)
Action- Weaken the call wall of bacteria.
Resistance- Is determined by inability to reach the target, inactivation by bacterial
enzymes and production of penicillin binding proteins that have a low affinity for it.
Active against a variety of bacteria
Direct toxicity: Low
Principal adverse effect: Allergic reaction
Structure includes a beta-lactam ring
