Table 1.

Interpretive criteria for inhibition zone diameter [20,21].

Antimicrobial Agent	Disc Conc.	Diameter of Inhibition Zone (mm)
		R	I	S
Pen	10 units	28 or less	-	29 or more
Amo-Cla	10–20 µg	19 or less	-	20 or more
Amp-Sul	10 µg	11or less	12–14	15 or more
Tet	30 µg	14 or less	15–18	19 or more
Ceft	30 µg	14 or less	15–22	23 or more
Cef	30 µg	≤21 mm	-	-
Ery	15 µg	13 or less	14–17	18 or more

R: Resistant, I: Intermediate, S: Sensitive. According to the National Committee for Clinical Laboratory standards. Cefoxitin (Cef); Penicillin (Pen); Ampicillin-sulbactam (Amp-Sul); Amoxicillin-clavulanic acid (Amo-Cla); Tetracycline (Tet); Cefotaxime (Ceft); Erythromycine (Ery).