TABLE 3.

Susceptibilities to beta-lactams distributed by species and ESBL gene typea

Species and ESBL typeNo. of isolatesMIC50/MIC90 of beta-lactam (μg/ml)
PiperacillinCephalothinCeftriaxoneCefotaximeCeftazidimeCefepimeCefoxitinAztreonamImipenem
P. mirabilis
    TEM+127>256/>256>256/>2564/88/164/164/164/80.5/21/2
P. stuartii
 TEM+22>256/>256>256/>2564/328/1632/>2562/>322/1284/161/2
K. pneumoniae
    TEM+32>256/>256>256/>2564/324/32>256/>2562/82/1632/>2560.25/0.5
    SHV+104>256/>256>256/>2568/328/32>256/>2562/162/16>256/>2560.25/0.5
    TEM+ and SHV+34>256/>256>256/>2568/328/32>256/>2562/162/16>256/>2560.25/0.25
    Non-TEM/non-SHV18>256/>256>256/>2568/>2568/32>256/>2562/84/16>256/>2560.25/0.5
E. coli
    TEM+11>256/>256>256/>2564/328/1616/1284/162/44/80.25/0.25
    SHV+28>256/>256>256/>2564/324/3232/>2561/82/416/>2560.25/0.25
E. aerogenes
    TEM+11>256/>256>256/>2568/168/16>256/>2561/2>256/>25616/320.25/0.25
    SHV+14>256/>256>256/>25616/6416/32>256/>2562/16>256/>25664/>2560.25/0.5
  • a MICs were measured by the quantitative E-test assay. Values are not reported when fewer than 10 isolates were available.