Table 2. Antibiotic resistance of the 157 ST398-MRSA isolates from the three groups of pigs.

	Total	Group 1 [2] [Farm B; 2016; AMX+COL]a	Group 2 [Farm B; 2018; AMX]a	Group 3 [Farm C; 2018; none]a
Total collection	157	58	48	51
FOX	157 (100%)	58 (100%)	48 (100%)	51 (100%)
ERY	106 (68%)	58 (100%)*	46 (96%)*	2 (4%)*
CLIN	155 (99%)	58 (100%)	48 (100%)	49 (96%)
CIP	67 (43%)	22 (38%)	42 (88%)*	3 (6%)*
TET	157 (100%)	58 (100%)	48 (100%)	51 (100%)
SXT	114 (73%)	31 (53%)*	44 (92%)*	39 (76%)
GEN	54 (34%)	29 (50%)	2 (4%)*	23 (45%)
QD	156 (99%)	58 (100%)	48 (100%)	50 (98%)
CHL	52 (33%)	51 (88%)*	1 (2%)*	0*
spa t011	108	22	38	48
FOX	108 (100%)	22 (100%)	38 (100%)	48 (100%)
ERY	60 (56%)	22 (100%)*	36 (95%)*	2 (4%)*
CLIN	106 (98%)	22 (100%)	38 (100%)	46 (96%)
CIP	63 (58%)	22 (100%)*	38 (100%)*	3 (6%)*
TET	108 (100%)	22 (100%)	38 (100%)	48 (100%)
SXT	99 (92%)	22 (100%)	38 (100%)	39 (81%)*
GEN	22 (20%)	0*	0*	22 (46%)
QD	107 (99%)	22 (100%)	38 (100%)	47 (98%)
CHL	15 (14%)	15 (68%)*	0*	0*
spa t108	45	36	6	3
FOX	45 (100%)	36 (100%)	6 (100%)	3 (100%)
ERY	41 (91%)	36 (100%)*	5 (83%)	0*
CLIN	45 (100%)	36 (100%)	6 (100%)	3 (100%)
CIP	0 (0%)	0*	0*	0*
TET	45 (100%)	36 (100%)	6 (100%)	3 (100%)
SXT	11 (24%)	9 (25%)	2 (33%)	0*
GEN	32 (71%)	29 (81%)*	2 (33%)	1 (33%)
QD	45 (100%)	36 (100%)*	6 (100%)	3 (100%)
CHL	37 (82%)	36 (100%)*	1 (17%)*	0*

FOX–Cefoxitin; ERY–Erythromycin; CLIN–Clindamycin; CIP–Ciprofloxacin; TET–Tetracycline; SXT–Trimethoprim-sulfamethoxazole; GEN–Gentamicin; QD–Quinupristin-dalfopristin; CHL–Chloramphenicol.

^aAntibiotics included in the feed regimen. AMX–Amoxicillin; COL–Colistin.

*Significant difference (p<0.01).

Numbers in bold indicate that ≥50% of the isolates are resistant to the antibiotic.