24 Questions
All microbes are innately resistant to gentamicin.
False
Antimicrobial resistance can be acquired through changes in the DNA.
True
Enterococci are intrinsically resistant to cephalosporins and amoxycillin.
True
Pseudomonas is intrinsically resistant to gentamicin.
False
Antimicrobial stewardship is only focused on reducing the use of antibiotics.
False
Horizontal gene transfer is the only mechanism of AMR gene transfer.
False
Selection pressure is the primary driver of antibiotic resistance development.
True
The misuse of antimicrobials is a major contributor to the development of antibiotic resistance.
True
The use of antimicrobials as growth promoters in animal husbandry is a factor promoting the emergence of antimicrobial resistance.
True
The altered target binding site is a mechanism of antibiotic modification or inactivation by enzymes.
False
Prolonged illness increases the opportunity for person-to-person spread of antimicrobial resistance.
True
Unregulated over-the-counter sales of antimicrobials are a factor promoting the emergence of antimicrobial resistance.
True
Decreased uptake and/or efflux is a mechanism of antibiotic modification or inactivation by enzymes.
False
Inadequate control of infection in healthcare facilities is a factor promoting the spread of antimicrobial resistance.
True
Antimicrobial stewardship refers to the development of new antimicrobial agents.
False
The misuse of antimicrobials increases the selection of resistant strains.
True
The DNA pieces transferred through transformation are usually long and contain multiple genes.
False
Bacterial viruses called bacteriophages are involved in the process of conjugation.
False
Irrational use of antibiotics in humans and animals helps to decrease drug resistance.
False
A combination of drugs is used to treat tuberculosis because the bacteria are naturally resistant to multiple drugs.
False
Neisseria spp. is an example of bacteria that can take up DNA from the environment through conjugation.
False
Transduction is the process of direct transfer of genetic material between bacteria through physical contact.
False
The acquisition of a novel PBP (PBP2a) by S. aureus is an example of vertical gene transfer.
False
Lysogeny is the process of incorporation of DNA into the bacterial chromosome by recombination.
False
Study Notes
Antibiotic Resistance and Stewardship
- MRSA (Methicillin-resistant Staphylococcus aureus): results from resistance to cloxacillin.
Mechanisms of Antibiotic Resistance
-
Three major methods:
- Antibiotic modification or inactivation by enzymes
- Altered target (binding) site
- Decreased uptake and/or efflux
Factors Promoting Emergence of Antimicrobial Resistance
- Unnecessary use: e.g., use in non-bacterial illnesses, inappropriate prophylaxis
- Inappropriate use: wrong choice of antimicrobial, wrong dose or duration of treatment
- Poor quality drugs
- Unregulated over-the-counter sales
- Self-medication
- Use of antimicrobials as growth promoters in animal husbandry
Factors Promoting Spread of Resistance
- Prolonged illness: increases opportunity for person-to-person spread
- Inadequate control of infection in health care facilities
- Lack of knowledge, training, guidelines for prescribers and patients
- Poor sanitation and overcrowding
- International travel and trade, population movements
Implications of Antimicrobial Resistance
- Complex, multi-factorial problem
- Increasing morbidity and lost productivity
- Increases mortality
- Major cost implications on health care for both drugs and hospitalization
Prevention of Antibiotic Resistance
- Overcome patient demand
- Training and knowledge
- Avoid economic incentives
- Regulation of animal husbandry and pharmaceutical industry
- Develop new drugs and vaccines
- Research to address gaps in international surveillance and policy
Antimicrobial Stewardship (AMS)
- Coordinated efforts to promote optimal use of antimicrobial agents
- Includes drug choice, dosing, route, and duration of administration
Genetic Mechanisms of Antimicrobial Resistance
- Intrinsic resistance: some microbes are innately resistant to particular classes of antimicrobials
- Acquired resistance: all microbes have the potential to acquire resistance due to changes in the DNA through transformation, conjugation, and transduction
Gene Transfer
- Transformation: takes up DNA from the environment, incorporating it into the bacterial chromosome
- Conjugation: direct transfer of a plasmid from donor to recipient cell through pili
- Transduction: transfer of genetic material between bacteria via bacterial viruses (bacteriophages)
Antibiotic Resistance and Clinical Practice
- Multidrug regimens: used to prevent emergence of resistance, e.g., in tuberculosis treatment
- Clinical examples: Klebsiella mutants resistant to cephalosporins, S. aureus acquiring novel PBP (PBP2a)
Learn about the 3 major mechanisms of antibiotic resistance, including modification, altered target sites, and decreased uptake. Understand the multiplier effect and how it contributes to the spread of resistant strains.
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