Gram positive

•  Unreliable against Staphylococci - develop resistance during therapy

• Bacillus anthracis

Gram negative

•  Pseudomonas

•  Enterobacteriaceae

•  Neisseria

•  Haemophilus

•  Moraxella

•  Pasteurella

Other

•  Atypicals including Legionella

Anaerobes

• Not reliable

Does not cover

•  Most gram positives

•  Streptococci

•  Enterococci

•  Stenotrophomonas

•  Anaerobes