Table 4.

Distribution of minimum inhibitory concentrations among Mycoplasma bovis isolates (n = 211 animals and 226 samples; lung samples = 194, nasal swabs = 23, laryngeal swabs = 1, pleural fluid = 1, heart = 2, joint fluid = 3, peritoneum = 1, abscess = 1).

					Distribution (%) of MICs (µg/mL)
Class	Categorya	Antimicrobial	MIC 50	%Rb	≤0.12	0.25	0.5	1	2	4	8	16	32	64
Aminoglycoside	II	GEN	16	58				1.3	1.3	8	31.4	58
	II	NEO	32	97.7						1.3	0.9	0.4	97.3
	III	SPE	8	0.9							88.9	8.8	0.9	64 = 0.4 >64 = 0.9
Fluorquinolone	I	ENRO	0.25	8	44.2	41.6	40	2.2	8
	I	DANO	0.25	17.7	15.5	42.5	24.3	17.7
Macrolide	II	TYLT	32	97.7			0.9			0.4	0.9	0.4	97.3
	II	TUL	64	92				0.4	0.9	0.4	0.9	3.5	1.8	92
	II	TIL	64	98.2						1.3		0.4		98.2
B lactams	I	XNL	8	98.2		1.8					98.2
	II	PEN	8	98.6	0.13	0.4				0.4	98.2
	II	AMP	16	98.6		0.9	0.4				0.4	98.2
Lincosamides	II	CLIN	16	73c		8.4	7.1	6.2	4.0	1.3	3.1	69.9
Phenicol	III	FFN	4	25.7		1.3	1.3	5.8	19.9	46	25.7
Tetracycline	III	OXY	8	80.1			1.3	0.9	8	9.7	80.1
	III	CTET	8	69.5			2.2	2.2	7.1	19	69.5
Pleuromutilin		TIA	1	2.2c			42	27.9	11.5	5.3	8.4	2.7	2.2

Trimethoprim sulpha (Category II): <2/38 = 2.2%, >2/38 = 97.8%.

Sulphahdimethoxine (Category III): <256 = 40.3%, >256 = 59.7%.

GEN, gentamycin/NEO, neomycin/SPE, spectinomycin; DAN, danofloxacin/ENRO, enrofloxacin; TYLT, tylosin/TUL, tulathromycin/TIL, tilmicosin; PEN, penicillin/AMP, ampicillin/XNL, ceftiofur; CLI, clindamycin; FFN, florfenicol; SXT, trimethoprim sulpha/SDM, sulphadimethoxine; OXY, oxytetracycline; CTET, chlortetracycline; TIA, tiamulin.

^aCategorization of Antimicrobial Drugs Based on Importance in Human Medicine—Veterinary Drug Directorate.

^bPathogen minimum inhibitory concentration breakpoints from CLSI standards.

^cNo CLSI breakpoint for this bovine respiratory disease pathogen/antimicrobial combination, simply notes susceptibility.

Values in red indicate resistant proportion of samples.

Shaded areas indicate concentrations not tested.