TABLE 1.

Antimicrobial resistance phenotypes of Salmonella Newport isolates from different animal and food types

Antimicrobial agentResistance breakpointa% Resistant isolates (n)
Human (n = 20)Cattle (n = 20)Swine (n = 13)Chicken (n = 10)Turkey (n = 8)Ground turkey (n = 7)Pork chop (n = 3)Total (n = 81)
Ampicillin≥3250 (10)80 (16)54 (7)40 (4)13 (1)14 (1)100 (3)52
Amoxicillin/clavulanic acid≥3250 (10)80 (16)54 (7)30 (3)014 (1)100 (3)49
Cefoxitin≥3250 (10)80 (16)54 (7)30 (3)014 (1)100 (3)49
Cephalothin≥3250 (10)80 (16)54 (7)40 (4)014 (1)100 (3)51
Ceftiofur≥850 (10)80 (16)54 (7)30 (3)014 (1)100 (3)49
Ceftriaxone≥645 (1)5 (1)000003
Chloramphenicol≥3250 (10)85 (17)46 (6)40 (4)014 (1)100 (3)51
Tetracycline≥1650 (10)95 (19)62 (8)40 (4)014 (1)100 (3)56
Amikacin≥3200000000
Kanamycin≥645 (1)40 (8)23 (3)20 (2)13 (1)0019
Gentamicin≥16020 (4)15 (2)10 (1)13 (1)14 (1)011
Streptomycinb≥6450 (10)90 (18)62 (8)40 (4)014 (1)100 (3)56
Sulfamethoxazole≥51250 (10)90 (18)62 (8)40 (4)13 (1)29 (2)100 (3)57
Trimethoprim/sulfamethoxazole≥430 (6)15 (3)15 (2)0014 (1)67 (2)17
Nalidixic acid≥3200000000
Ciprofloxacin≥400000000
  • a MIC (μg/ml) determined via broth microdilution methods in accordance with CLSI standards (37, 38).

  • b Interpretive criteria have not been established by the CLSI.