Table 1.

Antibiotics and spectrum of activity.

	Staphylococcus aureus, MSSA	Staphylococcus aureus, MRSA	Streptococcus pneumoniae	Enterococci	Coliforms	Coliforms, ESBL	Haemophilus influenzae	Pseudomonas	Acinetobacter	Anaerobes (Gram positive)	Anaerobes (Gram negative)	Mycoplasma	Site of action
Aminoglycosides	+	+	0	0	+	+	0	+	+	0	0	0	Ribosome
Carbapenems	++	0	++	0	++	++	++	+	+	+	++	0	Cell wall
Cephalosporins (3rd generation)	+	0	++	0	±	0	++	+	±	+	0	0	Cell wall
Fluoroquinolones	+	±	±	±	+	+	++	+	+	0	0	+	Nucleic acid
Glycopeptides	+	+	+	+	0	0	0	0	0	±	0	0	Cell wall
Lincosamides	+	±	±	0	0	0	0	0	0	+	±	0	Ribosome
Macrolides	+	±	±	0	0	0	±	0	0	±	0	+	Ribosome
Metronidazole	0	0	0	0	0	0	0	0	0	±	++	0	Nucleic acid
Monobactams	0	0	0	0	+	0	+	+	0	0	0	0	Cell wall
Nitrofurans	0	0	0	+	+	+	0	0	0	0	0	0	Nucleic acid
Penicillins	++	0	+	±	±	–	±	0	0	++	0	0	Cell wall
Penicillin plus β-lactamase inhibitors	+	0	+	±	+	±	+	+	±	++	++	0	Cell wall
Sulphonamides/folic acid inhibitors	+	+	±	±	+	+	+	0	±	0	0	0	Folate synthesis
Tetracyclines	+	+	±	0	±	±	+	0	±	+	±	+	Ribosome

Where activity varies within an antibiotic group, the most active commercially available agent is assumed.

0, Limited useful activity as monotherapy; ±, Variable activity. Efficacy often limited by resistance; +, Active. Likely to be clinically effective, but resistance may occur; ++, Highly active. Agent highly potent and resistance unusual.