Table 2.

Zone diameter breakpoints (mm) used for S. pneumoniae and H. influenzae isolates

	S. pneumoniae						H. influenzae
	CLSI			EUCAST			CLSI			EUCAST
Antimicrobial agent	R	I	S	R	I	S	R	I	S	R	I	S
Chloramphenicol	≤20	—	≥21	≤20	—	≥21	≤25	26–28	≥29	≤27	—	≥28
Clindamycin	≤15	16–18	≥19	≤18	—	≥19	NT	NT	NT	NT	NT	NT
Erythromycin	≤15	16–20	≥21	≤18	19–21	≥22	NT	NT	NT	NT	NT	NT
Tetracycline	≤24	25–27	≥28	≤21	22–24	≥25	≤25	26–28	≥29	≤21	22–24	≥25
SXT	≤15	16–18	≥19	≤14	15–17	≥18	≤10	11–15	≥16	≤19	20–22	≥23

SXT, trimethoprim/sulfamethoxazole; NT, not tested.