Table 3

Detection of IMP in CNS-NFGNR by three different methods

Strain groupIMP typeSpeciesNo. testedMIC (μg/ml) of:No. (%) of isolates with positive resultNo. (%) of indeterminate tests for Etest
IPMMEM
RangeNo. (%) of:RangeNo. (%) of:
Isolates of >4Isolates of >1Isolates of >4Isolates of >1IC assayDDSTEtest
IMP-producing NFGNRIMP-1P. aeruginosa244 to >6420 (83)24 (100)8 to >6424 (100)24 (100)24 (100)23 (96)20 (83)1 (4)
Acinetobacter spp.a1216 to >6412 (100)12 (100)8 to >6412 (100)12 (100)12 (100)12 (100)10 (83)2 (16)
Pseudomonas spp.b816 to >648 (100)8 (100)>648 (100)8 (100)8 (100)8 (100)8 (100)0 (0)
A. xylosoxidans416 to >644 (100)4 (100)32 to >644 (100)4 (100)4 (100)4 (100)3 (75)0 (0)
IMP-1 total484 to >6444 (91)48 (100)8 to >6448 (100)48 (100)48 (100)47 (97)41 (85)3 (6)
IMP-7P. aeruginosa564 to >645 (100)5 (100)>645 (100)5 (100)5 (100)5 (100)5 (100)0 (0)
IMP-10P. aeruginosa716 to >647 (100)7 (100)32 to >647 (100)7 (100)7 (100)7 (100)7 (100)0 (0)
A. xylosoxidans1>641 (100)1 (100)>641 (100)1 (100)1 (100)1 (100)1 (100)0 (0)
IMP-10 total816 to >648 (100)8 (100)32 to >648 (100)8 (100)8 (100)8 (100)8 (100)0 (0)
IMP-11P. aeruginosa1161 (100)1 (100)161 (100)1 (100)1 (100)1 (100)0 (0)1 (100)
Pseudomonas spp.1321 (100)1 (100)>641 (100)1 (100)1 (100)1 (100)1 (100)0 (0)
Acinetobacter genomospecies 131161 (100)1 (100)161 (100)1 (100)1 (100)1 (100)0 (0)0 (0)
IMP-11 total316 to 323 (100)3 (100)16 to >643 (100)3 (100)3 (100)3 (100)1 (33)1 (33)
IMP-19A. pittii232 to 642 (100)2 (100)8 to 162 (100)2 (100)2 (100)2 (100)2 (100)0 (0)
IMP-20P. aeruginosa3>643 (100)3 (100)>643 (100)3 (100)3 (100)3 (100)3 (100)0 (0)
IMP-40P. aeruginosa2>642 (100)2 (100)>642 (100)2 (100)2 (100)2 (100)2 (100)0 (0)
IMP-41P. aeruginosa1>641 (100)1 (100)>641 (100)1 (100)1 (100)1 (100)1 (100)0 (0)
IMP-42A. soli28 to 162 (100)2 (100)322 (100)2 (100)2 (100)2 (100)2 (100)0 (0)
IMP total744 to >6470 (94)74 (100)8 to >6474 (100)74 (100)74 (100)73 (98)65 (87)4 (5)
Non-IMP producing NFGNRNoneP. aeruginosa184 to 3217 (94)18 (100)4 to 6417 (94)18 (100)0 (0)1 (5)1 (5)0 (0)
Pseudomonas spp.240 (0)2 (100)322 (100)2 (100)0 (0)0 (0)0 (0)1 (50)
A. baumannii104 to 329 (90)10 (100)4 to 649 (90)10 (100)0 (0)0 (0)0 (0)0 (0)
A. xylosoxidans38 to 643 (100)3 (100)8 to 643 (100)3 (100)0 (0)0 (0)0 (0)0 (0)
Non-IMP total334 to 6430 (88)33 (100)4 to 6431 (93)34 (100)0 (0)1 (3)1 (3)1 (3)
Sensitivity (%)9410010010010098NAb
Specificity (%)1206010096NA
  • a Eight A. pittii strains, 2 Acinetobacter genomospecies 13 strains, 1 A. soli strain, and 1 A. johnsonii strain.

  • b NA, not applicable because data included indeterminate results.