Cephalosporins

• beta-lactams
• wider antibacterial specturm than penicillin and are resistant to some beta-lactamases
• broad spectrum
• safe
• don't treat enterobacter with cephalosporin

1st Generation

• e.g. cephalexin, ceftradine, cefaclor

Activity

• broad-spectrum
• Staphylococcus aureus (NOT MRSA), E.coli, Klebsiella, Proteus mirabilis, gram positive cocci (if flucloxacillin sensitive)
  • Staph. aureus produces beta-lactamase which destroys ampicillin
• NOT Pseudomonas, Enterobacter
• MIC ~5µg/ml

Pharmacokinetics

• well absorbed
• half life ~1 hour
• dose BDS/TDS 0.5-1g

Uses

• skin, soft tissue, urinary tract infections - will also have activity in chest infections but not ideal

2nd Generation

• e,g, cefuroxime
• more active - MIC 1µg/ml
  • Haemophilus influenzae, Enterobacter (but don't use for this), Citrobacter, Serratia, Bacteroides fragilis

Use

• chest infections
• usually IV
  • oral preparation, cefuroxine axetil has only 30% bioavailability

3rd Generation

• e.g. cefataxine, ceftazidime
• not good against staphylococcus
• short half-life
• ceftazidime has some activity against Pseudomonas, but check with microbiology department before using
• ceftriaxone - has longer half life for once daily dosing
• cefixime - oral preparation, use only for switching from IV to send home

4th Generation

• exist!
• cefepime, cefpirome
• active against most Enterobacteria and Pseudomonas