(c).

Number of isolates (n = 13) at a MIC (mg/l) (Magnetic Island)
Antibiotic agent	≤0.002	0.004	0.008	0.015	0.031	0.062	0.125	0.25		0.5		1	2		4		8		16		32	64	128	256	>256	% res
Amoxi./clav.								1		1		1	1		1		1	|	1		2	1	3			53.8
Ampicillin										1		1	2			|	1		1		2	5				69.2
Ceftiofur						1	3	1		1				|	1		3		3							53.8
Chloramphenicol										1		2	1		1		5		3	|						0
Doxycycline										1		2	1		1		5	|	3							23
Enrofloxacin							2	1	|	2		3			2		3									77
Erythromycin					1		2			1		4		|							5					38.5
Trim./sulf.				4	5	3	1				|															0