A 45 year old man presents to your hospital with cellulitis of the leg with some small areas of ulceration. He’s had this before, and has always swabbed positive for MRSA (methacillin resistent Staphylococcus aureus). Sure enough his GP swabbed him 2 days ago and he is growing out MRSA again. His GP also started him on Doxycycline and Clindamycin, which had worked well for him before, but this time his swab results show resistance to all of the tested oral agents.
The patient looks clinically well, and is a good candidate for out patient IV therapy with vancomycin. But, just as you are considering placing an IV you remember an advertisement you saw in one of the throw away journals that grace doctor’s bathroom stalls everywhere. You remember a drug called linezolid (aka: Zyvox, Zyvoxid, Zyvoxam), is this another oral option?
- Gram positive bacteria: Linezolid has broad clinical effect against most gram positive bacteria including Enterococcus (including VRE), Staphylococcus auerus (including MRSA), Streptococcus species, Nocardia, Listeria and Corynebacterium.
- Gram negative bacteria: Linezolid is ineffective against most gram negative bacteria. It has no effect on Pseudomonas or Enterobacter sp. There may be some effect against Moraxella, Pasteurella, Fusobacterium, Legionella, Bordetella, Haemophilus influenza, and Capnocytophaga. It is not a primary drug for gram negative infections.
- Mycobacterium: Linezolid is effective against mycobacteria and has been used as part of multi-drug treatment.
Linezolid is also a weak monoamine oxidase inhibitor.