16 Questions
What type of pathogens is benzylpenicillin effective against?
Gram-positive
What is the main advantage of using ampicillin and amoxycillin?
They are absorbed orally or may be given parenterally
What is the purpose of combining clavulanic acid with amoxycillin?
To protect amoxycillin from beta-lactamase-producing bacteria
What is the advantage of using flucloxacillin and methicillin?
They are beta-lactamase-resistant penicillins
What is the main use of cephalosporins in surgical practice?
To treat skin and soft tissue infections
What type of bacteria are cephalosporins active against?
Enterobacteria and S. aureus
What is the main indication for using benzylpenicillin?
To treat actinomycosis
What is the dosage of benzylpenicillin required for treating serious infections?
1.2 g 4-hourly
Which bacteria are not sensitive to any of the cephalosporins?
E. faecalis and E. faecium
What is the primary purpose of combining cephalosporins with an aminoglycoside or an imidazole?
To provide guaranteed anaerobic coverage
Which of the following aminoglycosides is effective against many strains of Pseudomonas?
Gentamicin
Why is it important to monitor serum levels of aminoglycosides?
To minimize the risk of ototoxicity and nephrotoxicity
What is the primary indication for using vancomycin?
Multi-resistant staphylococcal infections
What is metronidazole primarily used to treat?
Anaerobic infections
What is a benefit of using metronidazole?
It is particularly safe and can be administered orally, rectally, or intravenously
What is the benefit of using a single large dose of an aminoglycoside?
It may be safer and more effective due to the post-antibiotic effect
Study Notes
Penicillins
- Benzylpenicillin is effective against Gram-positive pathogens, including streptococci, clostridia, and some staphylococci.
- It is used to treat actinomycosis, spreading streptococcal infections, and can be used in combination with other antibiotics for mixed infections.
- High-dose intravenous benzylpenicillin (1.2g 4-hourly) is required for serious infections like gas gangrene.
Ampicillin and Amoxycillin
- These beta-lactam penicillins are absorbed orally or can be given parenterally.
- Amoxycillin is pharmacodynamically superior and effective against enterobacteriaceae, E. faecalis, and group D streptococci.
- Clavulanic acid is available combined with amoxycillin to protect against beta-lactamase-producing bacteria.
Flucloxacillin and Methicillin
- These beta-lactamase-resistant penicillins are used to treat staphylococcal beta-lactamase-producing organisms.
- Flucloxacillin has poor activity against other pathogens.
Cephalosporins
- Cefuroxime, cefotaxime, and ceftazidime are used in surgical practice.
- Cefuroxime and cefotaxime are effective against intra-abdominal skin and soft tissue infections, active against S. aureus and most enterobacteria.
- Ceftazidime is effective against P. aeruginosa and Gram-negative organisms.
Aminoglycosides
- Gentamicin and tobramycin are effective against Gram-negative enterobacteriaceae and Pseudomonas.
- Gentamicin is effective against many strains of Pseudomonas, but resistance develops rapidly.
- Aminoglycosides are inactive against anaerobes and streptococci.
- Monitoring of serum levels is necessary to avoid ototoxicity and nephrotoxicity.
Vancomycin
- Vancomycin is effective against Gram-positive bacteria, particularly multi-resistant staphylococcal infections.
- It is ototoxic and nephrotoxic, and serum levels should be monitored.
Metronidazole
- Metronidazole is active against all anaerobic bacteria and is safe for oral, rectal, or intravenous administration.
- It is effective against anaerobic cocci, Bacteroides, and Clostridia, and reduces anaerobic infections after abdominal and pelvic surgery.
This quiz covers the effectiveness of penicillin against Gram-positive pathogens, including streptococci, clostridia, and staphylococci. It also discusses the treatment of various infections, such as actinomycosis and gas gangrene.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
