تجربة 4 Flashcards
What are the different routes of administration for antibacterial drugs?
Topical, Oral, Intramuscular, Intravenous
What is the difference between narrow-spectrum and broad-spectrum antibiotics?
Narrow-spectrum works on a narrow range of organisms, while broad-spectrum works on a broad range of organisms but may disrupt normal flora
What are some examples of Gram-positive bacteria?
Staphylococci, Listeria
How do fluoroquinolones inhibit DNA/RNA synthesis?
They inhibit enzymes maintaining the supercoiling of DNA
What is the mechanism of action of penicillins and cephalosporins?
They irreversibly inhibit enzymes involved in the final steps of Gram-positive cell wall synthesis
What are some toxic effects that antibacterial drugs can cause?
Toxicity at high concentrations or adverse effects
How does the suppression of normal flora by antibiotics contribute to opportunistic infections?
When normal flora is killed, other pathogens may grow in high numbers
What are some examples of Gram-negative bacteria?
E.coli, Salmonella
In what situations are synergistic drug combinations used in treating infections?
When the action of one drug enhances the activity of another
What are some considerations when using tetracyclines?
Avoid in children under 8/12 years, during pregnancy, liver diseases, kidney insufficiency; avoid with certain supplements or medications
How do tetracyclines inhibit protein synthesis in bacteria?
They reversibly bind to the 30S subunit of ribosomes, blocking tRNA attachment
What is the difference between bacteriostatic and bactericidal drugs?
Bacteriostatic drugs rely on host immunity to eliminate pathogens, while bactericidal drugs are useful when host defenses cannot control the pathogen
How can bacteria develop resistance to antibiotics?
Inherent resistance, spontaneous mutations, acquisition of new genes
What are some potential allergic reactions to antibacterial drugs?
Hypersensitivities
What are the features of antibacterial/antimicrobial drugs?
Highly selective toxicity, low tendency for resistance development, rapid tissue distribution, no interactions with other drugs, relatively inexpensive
How do rifamycins work in inhibiting bacterial RNA synthesis?
They block prokaryotic RNA polymerase from initiating transcription
What is the role of beta-lactamase in antibiotic resistance?
Beta-lactamase breaks the critical beta-lactam ring, leading to resistance
Why is the use of broad-spectrum antibiotics a concern?
They can disrupt the normal flora of the body
How do sulfonamides inhibit folic acid metabolism in bacteria?
They mimic PABA and act as competitive inhibitors of dihydropteroate synthase
Why are sulfonamides considered bacteriostatic?
In the absence of folic acid, bacteria cannot grow or divide
Which class of drugs inhibits enzymes involved in the final steps of Gram-positive cell wall synthesis? a) Tetracyclines b) Penicillins c) Quinolones d) Sulfonamides
Answer: b) Penicillins ; Penicillins irreversibly inhibit enzymes involved in the final steps of Gram-positive cell wall synthesis, making them effective against Gram-positive bacteria.
What is the primary mechanism of action of rifamycins? a) Inhibition of protein synthesis b) Inhibition of cell wall synthesis c) Inhibition of folic acid metabolism d) Inhibition of RNA polymerase
Answer: d) Inhibition of RNA polymeras ;Rifamycins primarily inhibit prokaryotic RNA polymerase from initiating transcription, which disrupts bacterial RNA synthesis and inhibits bacterial growth.
What condition is a contraindication for the use of tetracyclines? a) Hypertension b) Pregnancy c) Diabetes d)
Answer: b) Pregnancy ;Tetracyclines are contraindicated in pregnancy due to their potential to cause adverse effects on fetal development, such as discoloration of teeth and inhibition of bone growth.
Asthma Which drug is known for causing hypoplasia of dental enamel and disorder of teeth formation? a) Quinolones b) Sulfonamides c) Aminoglycosides d) Vancomycin
Answer: b) Sulfonamides ;Sulfonamides are known for causing hypoplasia of dental enamel and disorder of teeth formation, especially when used in children or during pregnancy.
What is the spectrum of activity of broad-spectrum antibacterial drugs? a) They work only on Gram-positive organisms b) They work only on Gram-negative organisms c) They work on both Gram-positive and Gram-negative organisms, but may disrupt normal flora d) They work on both Gram-positive and Gram-negative organisms, without disrupting normal flora
Answer: c) They work on both Gram-positive and Gram-negative organisms, but may disrupt normal flora ;Broad-spectrum antibacterial drugs have a wide range of activity, targeting both Gram-positive and Gram-negative bacteria. However, their use may disrupt the normal microbial flora, leading to overgrowth of other pathogens.
