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. 2005 Apr;49(4):1572–1575. doi: 10.1128/AAC.49.4.1572-1575.2005

TABLE 2.

Phenotypic and genotypic characterization of 41 isolates carrying the blaCTX-M gene

Species Strain Hospitala CTX-M group pI(s)b Other β-lactamase gene product(s) MICc (μg/ml)
Antimicrobial resistance patternd
CTX CAZ ATM FEP FOX
C. freundii 03K892 K CTX-M-3 5.4, 7.4, 8.4, 8.7 TEM-1, OXA-30, AmpC 256 8 32 64 512 AMP AMK GEN KAN CHL TET STR SXT TMP
E. coli EC25 D CTX-M-3 5.4, 8.4 TEM-1 128 2 16 16 8 AMP AMK GEN KAN TET STR SXT TMP
E. coli 03K681 K CTX-M-3 5.4, 8.4 TEM-1 512 8 32 128 256 AMP AMK GEN KAN CHL TET STR SXT TMP
E. coli 03K203 K CTX-M-3 7.4, 8.0, 8.4 OXA-30, CMY-1 128 128 256 256 ≥512 AMP AMK GEN KAN STR SXT
K. pneumoniaee KP2 D CTX-M-3 7.4, 7.8, 8.4 OXA-30, DHA-1 256 128 256 32 256 AMP AMK KAN CHL STR SXT
K. pneumoniae KP7 D CTX-M-3 8.4 256 8 32 128 16 AMP AMK GEN KAN SXT TMP
K. pneumoniae KP9 D CTX-M-3 8.4 256 8 32 128 8 AMP AMK GEN KAN SXT TMP
K. pneumoniae 03K839 K CTX-M-3 5.4, 7.4, 7.8, 8.4 TEM-1, OXA-30, DHA-1 ≥512 256 512 256 ≥512 AMP AMK GEN KAN CHL STR SXT TMP
S. marcescens 03K188 K CTX-M-3 7.4, 8.4, 8.7 OXA-30, AmpC ≥512 128 256 512 ≥512 AMP AMK GEN KAN STR SXT
S. marcescens 03K196 K CTX-M-3 7.4, 8.4, 8.7 OXA-30, AmpC ≥512 128 128 512 ≥512 AMP AMK GEN KAN STR SXT
S. marcescens 03K201 K CTX-M-3 7.4, 8.4, 8.7 OXA-30, AmpC ≥512 64 128 512 ≥512 AMP AMK GEN KAN STR SXT
S. marcescens 03K205 K CTX-M-3 7.4, 8.4, 8.7 OXA-30, AmpC ≥512 128 128 512 ≥512 AMP AMK GEN KAN STR SXT
S. marcescens 03K168 K CTX-M-3 7.4, 8.4, 8.7 OXA-30, AmpC ≥512 64 128 >512 ≥512 AMP AMK GEN KAN STR SXT
S. marcescens 03K921 K CTX-M-3 8.4, 8.7 AmpC ≥512 32 128 512 256 AMP AMK GEN KAN STR SXT
S. marcescens 03K980 K CTX-M-3 8.4, 8.7 AmpC ≥512 64 256 512 ≥512 AMP AMK GEN KAN STR SXT
S. marcescens SM 16 D CTX-M-3 8.4 64 ≥1 32 32 8 AMP AMK GEN KAN STR SXT TMP
S. marcescens SM 3 D CTX-M-3 8.4 512 4 64 64 16 AMP AMK GEN KAN STR SXT TMP
Enterobacter aerogenes EA11 D CTX-M-15 5.4, 7.4, 7.6, 8.6 TEM-1, OXA-30, SHV-1 512 128 128 256 4 AMP STR SXT TMP
Enterobacter aerogenes EA6 D CTX-M-15 5.4, 7.4, 7.6, 8.6 TEM-1, OXA-30, SHV-1 512 128 128 256 4 AMP TET STR SXT TMP
Enterobacter aerogenes EA7 D CTX-M-15 5.4, 7.4, 7.6, 8.6 TEM-1, OXA-30, SHV-1 512 64 128 256 4 AMP TET STR SXT TMP
E. coli 03K969 K CTX-M-15 5.4, 7.4, 8.6 TEM-1, OXA-30 256 16 32 16 4 AMP GEN TET STR SXT TMP
E. coli 03K865 K CTX-M-15 5.4, 7.4, 8.6 TEM-54, OXA-30 256 8 16 4 2 AMP GEN KAN TET
E. coli 03K582 K CTX-M-15 5.4, 7.4, 8.6 TEM-54, OXA-30 256 32 64 128 8 TET
E. coli J133 E CTX-M-15 5.4, 7.4, 8.6 TEM-54, OXA-30 256 32 64 128 8 AMP GEN KAN STR SXT TMP
E. coli J144 E CTX-M-15 5.4, 7.4, 8.6 TEM-1, OXA-30 512 128 256 256 128 AMP GEN KAN TET SXT TMP
E. coli J158 E CTX-M-15 5.4, 7.4, 8.6 TEM-1, OXA-30 512 128 256 256 16 AMP GEN KAN TET
E. coli J159 E CTX-M-15 5.4, 8.6 TEM-1 512 64 256 256 32 AMP GEN TET SXT TMP
E. coli EC35 D CTX-M-15 5.4, 7.4, 8.6 TEM-1, OXA-30 ≥512 128 256 128 16 AMP GEN KAN TET
E. cloacae J187 E CTX-M-9 8.0, 8.5 AmpC 32 4 4 4 ≥512 AMP KAN CHL TET STR SXT TMP
E. cloacae 03K42 K CTX-M-9 8.0, 8.2, 8.5 SHV-12, AmpC 32 64 128 4 512 AMP KAN CHL TET SXT TMP
E. coli 03K380 K CTX-M-9 8.0, 8.2, 8.5 SHV-12, AmpC 8 32 32 <1 128 AMP KAN CHL TET STR SXT TMP
E. coli 03K776 K CTX-M-9 8.0, 8.5 AmpC 8 ≤1 1 <1 256 AMP KAN TET STR SXT TMP
E. coli EC27 D CTX-M-14 8.0 128 2 8 64 8 AMPTET
E. coli ECS D CTX-M-14 5.4, 8.0 TEM-1 512 8 32 64 32 AMP GEN KAN CHL TET STR SXT
E. coli J167 E CTX-M-14 5.4, 8.0 TEM-1 128 2 16 8 8 AMP GEN TET STR SXT TMP
E. coli 03K319 K CTX-M-14 5.4, 8.0, 8.5 TEM-1 32 ≤1 8 4 4 TET STR SXT
K. pneumoniae 03K930 K CTX-M-14 8.0 512 8 32 128 32 AMP KAN STR SXT
K. pneumoniae J22 E CTX-M-14 6.2,f8.0, 8.2 OXA, SHV-12 256 8 32 64 32 AMP KAN STR
K. pneumoniae J64 E CTX-M-14 6.2,f8.0, 8.2 OXA, SHV-12 256 8 512 64 8 AMP KAN STR
K. pneumoniae J1 E CTX-M-14 6.2,f8.0, 8.2 OXA, SHV-12 128 256 512 16 8 AMP KAN STR
K. pneumoniae J112 E CTX-M-14 6.2,f8.0, 8.2 OXA, SHV-12 256 512 512 32 8 AMP KAN STR
a

Hospital K is located in the city of Daegu, hospital D is in Cheonan, and hospital E is in Daejun in Korea.

b

The pI of β-lactamase as determined by IEF; underlined pIs correspond to the CTX-M enzymes.

c

MIC as determined by the agar dilution method. Abbreviations: CTX, cefotaxime; CAZ, ceftazidime; ATM, aztreonam; FEP, cefepime; FOX, cefoxitin.

d

Abbreviations: AMP, ampicillin; CHL, chloramphenicol; TET, tetracycline; STR, streptomycin; SXT, sulfisoxazole; TMP, trimethoprim; KAN, kanamycin; GEN, gentamicin; AMK, amikacin.

e

All K. pneumoniae isolates were positive for the PCR with the SHV primer sets, and further sequence determination revealed that these isolates have SHV-11, the β-lactamase located on the chromosome of K. pneumoniae, although the β-lactamase with a pI of 7.6 corresponding to the SHV-11 was not detected by the IEF analysis.

f

The β-lactamase with a pI of 6.2 was not inhibited by either 0.3 mM clavulanic acid or 0.3 mM cloxacillin, indicating an OXA-type β-lactamase. We did not perform further characterization of this β-lactamase.