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Table 1

Susceptibility testing results of 76 intll-positive and 238 intll-negative Proteus mirabilis isolates.

intl1-positive isolates (n = 76) ESBL positive n = 55
intl1-negative isolates (n = 238) ESBL positive n = 24
Antibiotic MIC (μg/ml) (no. of isolates) Resistance MIC (μg/ml) (no. of isolates) Resistance
Amoxicillin-clavulanic acida 16 (4), ≤ 8 (72) 5.2% 16 (2), ≤ 8 (236) 0.1%
Piperacillina ≥ 256 (75), 64 (1) 98.7% ≥ 256 (35), 32 (203) 14.7%
Cefotaximea ≥ 256 (29), 64 (13), 16–32 (12), ≤ 2 (22) 71.1% ≥ 256 (10), 64 (7), 16-32 (7), ≤ 2 (214) 10.1%
Ceftazidime 2(1), ≤ 0.5 (75) 1.3% ≤ 0.5 (238) 0%
Cefepimea 32 (1), 4 (3), ≤ 2 (72) 5.3% 4 (1), ≤ 2 (237) ~0%
Cefoxitina 16–32 (3), ≤ 8 (73) 3.9% 16 (1), ≤ 8 (237) ~0%
Meropenem ≤ 0.5 (76) 0% ≤ 0.5 (238) 0%
Gentamicina ≥ 16 (66), ≤ 2 (10) 86.8% ≥ 16 (21), ≤ 2 (217) 8.8%
Amikacina ≥ 16 (65), ≤ 2 (11) 85.5% ≥ 16 (17), ≤ 2 (221) 7.1%
Ciprofloxacina ≥ 4 (28), ≤ 1 (48) 36.8% ≥ 4 (11), ≤ 1 (227) 4.6%

The chi-square test was employed to compare the antimicrobial resistance rate between intll-positive and intll-negative P. mirabilis isolates. Susceptibility was determined according to the interpretive criteria of the Clinical and Laboratory Standards Institute 2005.

a

p-value is less than 0.05.