Podcast
Questions and Answers
What is the primary reason for initiating empiric therapy in critically ill patients?
What is the primary reason for initiating empiric therapy in critically ill patients?
Which type of antimicrobial drug kills bacteria rather than inhibiting their growth?
Which type of antimicrobial drug kills bacteria rather than inhibiting their growth?
Which characteristic defines broad-spectrum antimicrobial drugs?
Which characteristic defines broad-spectrum antimicrobial drugs?
Which factor may accelerate antibiotic resistance according to the content?
Which factor may accelerate antibiotic resistance according to the content?
Signup and view all the answers
What does drug resistance refer to in microbiology?
What does drug resistance refer to in microbiology?
Signup and view all the answers
What method of genetic transfer involves direct contact between bacteria?
What method of genetic transfer involves direct contact between bacteria?
Signup and view all the answers
What is an example of a broad-spectrum antibiotic?
What is an example of a broad-spectrum antibiotic?
Signup and view all the answers
Which of the following is NOT a mechanism through which drug resistance can be acquired?
Which of the following is NOT a mechanism through which drug resistance can be acquired?
Signup and view all the answers
What method involves the uptake of free DNA by a bacterium?
What method involves the uptake of free DNA by a bacterium?
Signup and view all the answers
Which mechanism decreases drug accumulation in bacteria?
Which mechanism decreases drug accumulation in bacteria?
Signup and view all the answers
Which of the following enzymes is known for cleaving the beta-lactam ring?
Which of the following enzymes is known for cleaving the beta-lactam ring?
Signup and view all the answers
Why is it not advisable to use antibiotics prophylactically?
Why is it not advisable to use antibiotics prophylactically?
Signup and view all the answers
Which of the following is a method of gene transfer between bacteria?
Which of the following is a method of gene transfer between bacteria?
Signup and view all the answers
How do alterations of drug-sensitive binding sites contribute to drug resistance?
How do alterations of drug-sensitive binding sites contribute to drug resistance?
Signup and view all the answers
What is one of the biochemical mechanisms of antimicrobial resistance?
What is one of the biochemical mechanisms of antimicrobial resistance?
Signup and view all the answers
Which antibiotic mechanism is associated with aminoglycosides?
Which antibiotic mechanism is associated with aminoglycosides?
Signup and view all the answers
What does the concept of selective toxicity refer to?
What does the concept of selective toxicity refer to?
Signup and view all the answers
What is empiric therapy?
What is empiric therapy?
Signup and view all the answers
What is meant by the chemotherapeutic spectrum of an antibiotic?
What is meant by the chemotherapeutic spectrum of an antibiotic?
Signup and view all the answers
Which is a distinguishing feature between bacteriostatic and bactericidal antibiotics?
Which is a distinguishing feature between bacteriostatic and bactericidal antibiotics?
Signup and view all the answers
Which of the following is a common mechanism of antibiotic resistance?
Which of the following is a common mechanism of antibiotic resistance?
Signup and view all the answers
What are the potential consequences of using antibiotic combinations?
What are the potential consequences of using antibiotic combinations?
Signup and view all the answers
What is the primary goal when selecting an antimicrobial drug for treatment?
What is the primary goal when selecting an antimicrobial drug for treatment?
Signup and view all the answers
Why is monitoring drug concentration crucial in antimicrobial therapy?
Why is monitoring drug concentration crucial in antimicrobial therapy?
Signup and view all the answers
In what situation is the use of antibiotic combinations deemed necessary?
In what situation is the use of antibiotic combinations deemed necessary?
Signup and view all the answers
What is an example of a situation wherein prophylactic antibiotics are utilized?
What is an example of a situation wherein prophylactic antibiotics are utilized?
Signup and view all the answers
Which complication can arise from therapy with broad spectrum antibiotics?
Which complication can arise from therapy with broad spectrum antibiotics?
Signup and view all the answers
Which of the following correctly defines bactericidal antibiotics?
Which of the following correctly defines bactericidal antibiotics?
Signup and view all the answers
Which statement regarding bacterial resistance is true?
Which statement regarding bacterial resistance is true?
Signup and view all the answers
What is the purpose of empiric therapy in antibiotic treatment?
What is the purpose of empiric therapy in antibiotic treatment?
Signup and view all the answers
What is one potential direct toxicity observed with aminoglycosides?
What is one potential direct toxicity observed with aminoglycosides?
Signup and view all the answers
What is the concept of selective toxicity in antimicrobial agents?
What is the concept of selective toxicity in antimicrobial agents?
Signup and view all the answers
Study Notes
Chemotherapy of Infections
- The term chemotherapy was developed by Ehrlich at the beginning of the 20th century to describe using chemicals to treat diseases
- Antibiotics are substances produced naturally by microorganisms or synthetically that kill or inhibit the growth of other microorganisms
Selective Toxicity
- Chemotherapeutic drugs should be toxic to invading organisms and innocuous to the host
- This is based on biochemical differences between pathogens and the host
- Drug concentration must be carefully controlled to prevent damage to the host
Empiric Therapy
- When a patient requires urgent therapy, empiric therapy is used
- Empiric therapy involves choosing a drug in the absence of sensitivity data, influenced by the site of infection and patient history
- Therapy should be initiated after specimens for laboratory analysis are taken and before culture results are available
Antimicrobial Drugs
- Bacteriostatic Drugs: inhibit bacterial growth
- Bactericidal Drugs: kill bacteria
Chemotherapeutic Spectra
- Narrow Spectrum: affects a single or limited group of microorganisms, e.g., Isoniazid against mycobacteria only
- Extended Spectrum: affects gram + and a significant number of gram - bacteria, e.g. Ampicillin
- Broad Spectrum: affects a wide variety of microbial species, e.g., Tetracyclines and Chloramphenicol
Drug Resistance
- Drug resistance is the ability of a microorganism to withstand an antibiotic to which they were once sensitive
- Resistance can be accelerated by a variety of factors, including human practices
Mechanism of Drug Resistance
- Mutations: changes in the DNA sequence of the bacteria
- Gene Amplifications: an increase in the number of copies of a gene, which leads to increased expression of the gene product
- Plasmids: extrachromosomal DNA that can transfer resistance genes
- Transposons: mobile DNA elements that can insert into the bacterial chromosome and transfer resistance genes
- Gene Cassettes and Integrons: provide a mechanism for the acquisition and expression of multiple resistance genes
- Conjugation: transfer of genetic material between bacteria through direct contact
- Transductions: transfer of genetic material between bacteria through a bacteriophage
- Transformation: uptake of free DNA by a bacterium
Biochemical Mechanisms of Resistance
- Alteration of drug-sensitive binding site: The target for the antibiotic can be altered, preventing the antibiotic from binding
- Production of enzymes that inactivate the drug: Bacteria can produce enzymes that break down or inactivate the antibiotic
- Decreased drug accumulation in bacteria: Bacteria can decrease the uptake of the antibiotic or increase the efflux of the antibiotic
- Alteration of enzyme pathways: The antibiotic can be prevented from working by altering the pathway that the antibiotic targets
Antimicrobial Combinations and Prophylaxis
- It is therapeutically advisable to treat patients with one agent specific for the infecting microorganism
- Using antibiotics prophylactically is generally unadvisable
- Antibiotic combinations are necessary in some situations:
- Mixed infections
- Life-threatening conditions
- When there is a risk of developing resistant microorganisms
Prophylactic Antibiotics
- Prophylactic antibiotics are used to prevention of infections in certain situations:
- Prevention of streptococcal infections in patients with rheumatic heart disease
- Pretreatment of patients undergoing dental extractions who have implanted prosthetic devices
- Prevention of TB or Meningitis in individuals in close contact with infected patients
- Treatment prior to certain surgical procedures
Complications of Antibiotic Therapy
- Direct Toxicity: can be a side effect of the antibiotic, e.g., Aminoglycoside ototoxicity
- Hypersensitivity: allergic reactions can occur, ranging from urticaria to anaphylactic shock
- Superinfection: can occur with broad-spectrum antibiotics, allowing opportunistic organisms to overgrow
Classification of Antimicrobial Agents
- Antibiotics are classified by their mechanism of action which defines their target
- Classes include:
- Beta-lactam antibiotics
- Macrolide antibiotics
- Aminoglycoside antibiotics
- Fluoroquinolones
- Tetracyclines
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
Test your knowledge on the principles of chemotherapy as it relates to infections. This quiz covers topics such as selective toxicity, empiric therapy, and the role of antimicrobial drugs. Understand how these concepts are crucial in treating infectious diseases effectively.
