TABLE 2.

Antimicrobial resistance patterns of study strainsa

Antimicrobial agent% (no.) of resistant strainsb
AmpC producers (n = 232)Non-AmpC producers (n = 183)
Amoxicillin-clavulanate66 (152)43 (79)
Ampicillin96 (223)82 (150)
Cefazolin55 (127)36 (65)
Ceftazidime1.3 (3)1.1 (2)
Ceftriaxone2.1 (5)11 (21)
Piperacillin-tazobactam4.7 (11)2.2 (4)
Cefotetan0 (0)0 (0)
Imipenem0 (0)0 (0)
Ciprofloxacin45 (105)19 (35)
Levofloxacin44 (102)19 (34)
Nitrofurantoin7.3 (17)1.6 (3)
Gentamicin27 (63)25 (45)
Amikacin1.3 (3)2.2 (4)
Tobramycin26 (60)18 (33)
Trimethoprim-sulfamethoxazole51 (118)33 (60)
  • a As determined with Vitek GNS 121 cards.

  • b Cefoxitin MICs were ≥32 μg/ml for AmpC producers and <32 μg/ml for non-AmpC producers, as determined by broth microdilution.