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Table 2 Antibiotic resistances of Listeria monocytogenes isolates from raw fresh vegetable samples

From: Genetic characteristics and virulence of Listeria monocytogenes isolated from fresh vegetables in China

Antimicrobial class Antimicrobial agent (disk content, μg or U) Critical value (mm) Sample number(%)
S I R S I R
Aminoglycosides Kanamycin(30) ≥18 14–17 ≤13 26 (86.7) 2 (6.7) 2 (6.7)
Gentamicin(10) ≥15 13–14 ≤12 28 (93.3) 0 2 (6.7)
Streptomycin(10) ≥15 12–14 ≤11 19 (63.3) 9 (30) 2 (6.7)
Fluoroquinolones Levofloxacin(5) ≥19 16–18 ≤15 28 (93.3) 2 (6.7) 0
Ciprofloxacin(5) ≥21 16–20 ≤15 22 (73.3) 7 (23.3) 1 (3.3)
Folate pathway inhibitors Sulfamethoxazole /trimethoprim (23.75/1.25) ≥16 11–15 ≤10 30 (100) 0 0
β-lactam group Sulbactam/ampicilin(10/10) ≥15 12–14 ≤11 29 (96.7) 1 (3.3) 0
Macrolides Erythromycin(15) ≥23 14–22 ≤13 27 (90) 2 (6.7) 1 (3.3)
Ansamycins Rifampin(5) ≥20 17–19 ≤16 22 (73.3) 6 (20) 2 (6.7)
Lincosamides Clindamycin(2) ≥21 15–20 ≤14 4 (13.3) 7 (23.3) 19 (63.3)
Tetracyclines Tetracycline(30) ≥19 15–18 ≤14 29 (96.7) 0 1 (3.3)
Doxycycline(30) ≥16 13–15 ≤12 29 (96.7) 0 1 (3.3)
Glycopeptides Vancomycina(30) ≥17 15–16 ≤14 25 (83.3) 3 (10) 2 (6.7)
Phenicols Chloramphenicol (30) ≥18 13–17 ≤12 28 (93.3) 2 (6.7) 0
β-Lactam Ampicillin <2 μg/mL ≥2 μg/mL 30 (100.0) 0 (0) 0 (0)
β-Lactam Penicillin <2 μg/mL ≥2 μg/mL 30 (100.0) 0 (0) 0 (0)
  1. a: The critical values of Enterococcus; the critical values of Staphylococcus; S susceptible, I intermediate, R resistant