. 2020 Jul 15;8(7):1048. doi: 10.3390/microorganisms8071048

Table 2.

AMR (antimicrobial resistance) profiles among 241 E. coli isolates by animal food category.

Antimicrobial Class	Antimicrobial Agent	Resistant Breakpoint (μg/mL)	No. (%) of Resistant Isolates
Antimicrobial Class	Antimicrobial Agent	Resistant Breakpoint (μg/mL)	All (n = 241)	Animal Feed (n = 200)	Pet Food (n = 41)
Aminoglycosides	Amikacin	≥ 64	0 (0)	0 (0)	0 (0)
	Gentamicin	≥ 16	0 (0)	0 (0)	0 (0)
	Kanamycin	≥ 64	2 (0.8)	1 (0.5)^A	1 (2.4)^A
	Streptomycin	≥ 64	11 (4.6)	7 (3.5)^A	4 (9.8)^A
Β-Lactam/β-Lactamase Inhibitor Combinations	Amoxicillin-Clavulanic Acid	≥ 32/16	1 (0.4)	0 (0)^B	1 (2.4)^A
Cephems	Cefoxitin	≥ 32	1 (0.4)	0 (0)^B	1 (2.4)^A
	Ceftiofur	≥ 8	0 (0)	0 (0)	0 (0)
	Ceftriaxone	≥ 4	0 (0)	0 (0)	0 (0)
Folate Pathway Inhibitors	Sulfisoxazole	≥ 512	7 (2.9)	6 (3)^A	1 (2.4)^A
Folate Pathway Inhibitors	Trimethoprim-Sulfamethoxazole	≥ 4/76	2 (0.8)	2 (1)^A	0 (0)^A
Penicillins	Ampicillin	≥ 32	7 (2.9)	6 (3)^A	1 (2.4)^A
Phenicols	Chloramphenicol	≥ 32	0 (0)	0 (0)	0 (0)
Quinolones	Ciprofloxacin	≥ 1	2 (0.8)	2 (1)^A	0 (0)^A
Quinolones	Nalidixic Acid	≥ 32	2 (0.8)	2 (1)^A	0 (0)^A
Tetracyclines	Tetracycline	≥ 16	27 (11.2)	23 (11.5)^A	4 (9.8)^A

NARMS breakpoints for ceftiofur and streptomycin were used. In each row, percentages followed by different uppercase letters (A or B) were significantly different (p < 0.05) in resistance rate between isolates recovered from animal feed and pet food.