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Table 2 Frequency of antimicrobial resistance among APEC isolates from broiler chickens by disc diffusion method

From: Identification of Escherichia coli from broiler chickens in Jordan, their antimicrobial resistance, gene characterization and the associated risk factors

Antimicrobials (abbreviation) Disc content (μg) Disc diffusion interpretive criteriaa (mm) E. coli (n =  269)
R S Number ( % )of resistant isolates
β – lactams
 Amoxicillin (AX) 25 <14 ≥14 251 (93.3%)
 Azetronem (ATM) 30 ≤21 ≥26 15 (5.6%)
 Imipenem (IPM) 10 ≤16 ≥22 0 (0%)
β – lactamase inhibitors
 amoxicillin – clavulanic acid (AML) 20/10 <19 ≥19 190 (70.6%)
 Tetracyclines
 Doxycycline (DO) 30 ≤10 ≥ 14 248 (92.2%)
 Oxytetracyclin (OT) 30 ≤11 ≥15 148 (55%)
 Chlortetracycline (CHL) 10 ≤13 ≥17 201 (74.7%)
Sulfonamides
 Sulphamethoxazole-trimethoprim (SXT) 23.75/1.25 ≤11 ≥14 257 (95.5%)
Fluoroquinolones
 Enrofloxacin (ENR) 5 ≤15 ≥21 227 (84.4%)
 Ciprofloxacin (CIP) 5 ≤24 ≥26 172 (63.9%)
Aminoglycosides
 Spectinomycin (SH) 25 ≤11 ≥15 248 (92.2%)
 Gentamicin (CN) 10 ≤14 ≥17 154 (57.2%)
 Apramycin (APR) 15 ≤12 ≥15 147 (54.6%)
Cephalosporin
 Cephalexin (CL) 30 <14 ≥14 236 (87.7%)
 Ceftazidime (CZC) 30 ≤19 ≥22 20 (7.4%)
 Ceftriaxone (CRO) 30 ≤22 ≥25 13 (4.8%)
 Cefepime (FEP) 30 ≤24 ≥27 9 (3.3%)
Phosphoric acid derivatives
 Fosfomycin (FOS) 50 <24 ≥24 80 (30%)
Phenicol
 Florfenicol (FFC) 30 ≤10 ≥21 252 (93.7%)
  1. aInterpretive criteria: depends on reference strain E. coli ATCC 25922, demonstrated in CLSI 2012, supplement M100-S22, Vol.32, No.3, Table 2A