Antibiotics and Infections

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Questions and Answers

What type of pathogens is benzylpenicillin effective against?

Gram-positive (correct)

Fungi

Viruses

Gram-negative

What is the main advantage of using ampicillin and amoxycillin?

They are effective against fungi

They are absorbed orally or may be given parenterally (correct)

They are effective against Gram-negative bacteria

They are effective against Gram-positive bacteria

What is the purpose of combining clavulanic acid with amoxycillin?

To protect amoxycillin from beta-lactamase-producing bacteria (correct)

To increase the dosage of amoxycillin

To increase the absorption of amoxycillin

To reduce the side effects of amoxycillin

What is the advantage of using flucloxacillin and methicillin?

They are beta-lactamase-resistant penicillins Signup and view all the answers

What is the main use of cephalosporins in surgical practice?

To treat skin and soft tissue infections Signup and view all the answers

What type of bacteria are cephalosporins active against?

Enterobacteria and S. aureus Signup and view all the answers

What is the main indication for using benzylpenicillin?

To treat actinomycosis Signup and view all the answers

What is the dosage of benzylpenicillin required for treating serious infections?

1.2 g 4-hourly Signup and view all the answers

Which bacteria are not sensitive to any of the cephalosporins?

E. faecalis and E. faecium Signup and view all the answers

What is the primary purpose of combining cephalosporins with an aminoglycoside or an imidazole?

To provide guaranteed anaerobic coverage Signup and view all the answers

Which of the following aminoglycosides is effective against many strains of Pseudomonas?

Gentamicin Signup and view all the answers

Why is it important to monitor serum levels of aminoglycosides?

To minimize the risk of ototoxicity and nephrotoxicity Signup and view all the answers

What is the primary indication for using vancomycin?

Multi-resistant staphylococcal infections Signup and view all the answers

What is metronidazole primarily used to treat?

Anaerobic infections Signup and view all the answers

What is a benefit of using metronidazole?

It is particularly safe and can be administered orally, rectally, or intravenously Signup and view all the answers

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 Signup and view all the answers

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.

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Description

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.