Table 2.

Antibiotic breakpoints for anaerobes from Clinical and Laboratory Standards Institute guidelines (CLSI, 2008)

Antibiotics	Susceptible (μg ml−1)	Resistant (μg ml−1)
Clindamycin	⩽2	⩾8
Chloramphenicol	⩽8	⩾32
Tetracycline	⩽8	⩾32
Moxifloxacin	⩽2	⩾8
Levofloxacin*	⩽2	⩾8
Gatifloxacin	⩽2	⩾8

^*Levofloxacin breakpoints could be ⩽2 μg ml⁻¹ (susceptible) and ⩾8 μg ml⁻¹ (resistant) and erythromycin breakpoints could be ⩽0.5 μg ml⁻¹ (susceptible) and ⩾32 μg ml⁻¹ (resistant), as no standard has been defined by the CLSI for anaerobes.