Table 2.

Reported antimicrobial use among 50 swine finishing barns located in 5 U.S. states screened for the presence of CTX-M cephalosporinase-producing enteric bacteria^c

Antimicrobial use	All barns (n = 50)		CTX-M (+) barnsa (n = 8)		CTX-M (−) barnsa (n = 42)
	n	Proportion	n	Proportion	n	Proportion
Ceftiofurb	43	0.86	7	0.88	36	0.86
Therapy	24	0.48	6	0.75	18	0.43
Prefinishing	41	0.82	7	0.88	34	0.81
Antimicrobials in feed	43	0.86	7	0.88	37	0.88
Bacitracin	2	0.04	0	0	2	0.05
Carbadox	7	0.14	3	0.38	4	0.10
Lincomycin	13	0.26	2	0.25	0	0.26
Macrolide	11	0.22	0	0	0	0.26
Tetracycline	25	0.5	5	0.63	20	0.48
Tiamulin	9	0.18	3	0.38	6	0.14
Virginiamycin	1	0.02	0	0	1	0.02
Antimicrobials in water	7	0.14	1	0.13	6	0.14
Gentamicin	1	0.02	1	0.13	0	0
Lincomycin	1	0.02	0	0	1	0.02
Penicillin	3	0.06	0	0	3	0.07
Sulfamethazine	1	0.02	0	0	1	0.02
Tetracycline	3	0.06	0	0	3	0.07
Tiamulin	2	0.04	0	0	2	0.05
Parenteral antimicrobialsd	37	0.74	8	1	29	0.69
Florfenicol	1	0.02	0	0	1	0.02
Fluoroquinolone	3	0.06	0	0	3	0.07
Lincomycin	15	0.3	4	0.50	11	0.26
Penicillin	17	0.34	5	0.63	12	0.29
Tetracycline	7	0.14	1	0.13	6	0.14
Tylosin	5	0.1	0	0	5	0.12

^aCTX-M (+) barns, barns in which CTX-M cephalosporinase-producing enteric bacteria were found; CTX-M (−) barns, barns in which CTX-M cephalosporinase-producing enteric bacteria were not found.

^bCeftiofur therapy indicates that one or more individual sick pigs in the finishing barn received ceftiofur therapy. Ceftiofur prefinishing indicates that one or more pigs in the barn had received therapeutic or prophylactic ceftiofur treatment in the farrowing or nursery facility prior to entering the finishing barn.

^cFour rows are shown in boldface type because they present summary values for the categories of antimicrobial use.

^dParenteral antimicrobials indicate treatment of one or more individual pigs in a barn with the antimicrobial drug.