Table 1.

Antimicrobial agents, suppliers, disk contents, and interpretative criteria used for disk susceptibility testing.

Antimicrobial	Supplier	Supplier code	Disk content (μg)	Zone diameter (mm) breakpointsc
				S	I	R
Amoxicillin/clavulanic Acida	BD	AMC-30	20/10	≥27	n/a	≤26
Ampicillina	BD	AM-10	10	≥27	n/a	n/a
Ceftiofurb	BD	XNL-30	30	≥21	18–20	≤17
Danofloxacinb	Pfizer	DNO	5	≥22	n/a	n/a
Erythromycina	BD	E-15	15	≥27	25–26	≤24
Florfenicolb	BD	FF-30	30	≥19	15–18	≤14
Gentamicinb	BD	GM-10	10	≥15	13–14	≤12
Oxytetracyclinea	BD	T-30	30	≥23	n/a	n/a
Spectinomycinb	BD	SPT-100	100	≥14	11–13	≤10
Sulfamethoxazolea/trimethoprim	BD	SXT	23.75/1.25	≤24	n/a	n/a
Tilmicosinb	BD	TIL-15	15	≥14	11–13	≤10
Tulathromycinb	Pfizer	TUL	30	≥18	15–17	≤14

^aM45-A: Methods for antimicrobial dilution and disk susceptibility testing of infrequently isolated or fastidious bacteria; approved guideline (CLSI, 2008b). Due to the unavailability MIC breakpoints for Mannheimia spp., guidelines for Pasteurella spp. were followed.

^bM31-A3: Performance standard for antimicrobial disk and dilution susceptibility tests for bacteria isolated from animals; approved standard—third edition (CLSI, 2008a)

^cZone diameter value used to indicate susceptible (S), intermediate (I) and resistant (R), n/a, not available.