Table 3.

Inhibition zone diameters and MICs for P. mirabilis isolates with different β-lactamase resistance phenotypes

β-Lactam phenotype (no. of isolates)AmoxicillinAmoxicillin + clavulanic acid (2 μg/ml)TicarcillinTicarcillin + clavulanic acid (2 μg/ml)Cephalothin
Mean zone diam (mm) ± SDMIC range (μg/ml)MIC90 (μg/ml)Mean zone diam (mm) ± SDMIC range (μg/ml)MIC90 (μg/ml)Mean zone diam (mm) ± SDMIC range (μg/ml)MIC90(μg/ml)Mean zone diam (mm) ± SDMIC range (μg/ml)MIC90 (μg/ml)Mean zone diam (mm) ± SDMIC range (μg/ml)MIC90 (μg/ml)
PL (23)12.5 ± 2.116–646429.0 ± 1.9≤2≤224.2 ± 3.1≤8–16≤234.8 ± 1.9≤2≤225.6 ± 2.0≤2–84
PI (28)6.0 ± 032–1,02451226.7 ± 2.0≤2–4415.3 ± 5.8≤8–128431.2 ± 2.6≤2≤222.9 ± 2.4≤2–84
PH (53)6.0 ± 0512–>2,048>2,04821.1 ± 3.2≤2–128326.3 ± 0128–1,0243228.4 ± 3.0≤2–16818.7 ± 2.4≤2–1616
ESBL (74)6.0 ± 0256–>2,0481,02426.3 ± 2.3≤2–8≤27.3 ± 1.8128–>1,024≤230.5 ± 1.7≤2–8≤213.9 ± 2.88–12864
IRT/OXA (39)6.1 ± 0.6128–2,0481,02410.9 ± 3.232–1,02425621.2 ± 5.9≤8–6425628.1 ± 2.2≤2–321624.1 ± 1.6≤2–84