Volume 14, Number 7—July 2008
Letter
Klebsiella pneumoniae Carbapenemase–2, Buenos Aires, Argentina
Table
Antibiotic susceptibility, isolectric focusing of β-lactamases and PCR of antimicrobial resistance determinants in Klebsiella pneumoniae, Citrobacter freundii clinical isolates, Salmonella transconjugants, and recipient and control strains*
Type of testing | Clinical isolates |
Transconjugants and recipient strains |
Control strains |
||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
K.p. M9171 | C.f. M9169 | Salmonella M9204† | Salmonella M9190‡ | Salmonella M1744 | K.p. D5/07§ | K.p. C2¶ | E. coli ATCC 25922 | ||||
MICs (µg/mL) | |||||||||||
Antimicrobial agent | |||||||||||
Imipenem | 32 | 1.0 | 1.0 | 1.0 | 0.12 | 2.0 | 0.12 | 0.25 | |||
Impenem/clavulanate | 32 | 0.25 | 0.25 | 0.25 | 0.12 | 0.5 | 0.12 | 0.25 | |||
Impenem/APB | 2.0 | 0.12 | 0.25 | 0.12 | 0.12 | 0.12 | 0.12 | 0.25 | |||
Imipenem/EDTA# | 32 | 0.25 | 1.0 | 1.0 | 0.12 | 2.0 | 0.12 | 0.12 | |||
Meropenem | 32 | 1.0 | 0.5 | 1.0 | 0.015 | 2.0 | 0.03 | 0.03 | |||
Meropenem/clavulanate | 32 | 0.12 | 0.03 | 0.06 | 0.015 | 1.0 | 0.03 | 0.03 | |||
Meropenem/APB | 1.0 | 0.06 | 0.03 | 0.03 | 0.015 | 0.12 | 0.03 | 0.03 | |||
Meropenem/EDTA# | 32 | 1.0 | 0.5 | 1.0 | 0.015 | 2.0 | 0.03 | 0.03 | |||
Ertapenem | 128 | 2.0 | 1.0 | 1.0 | 0.008 | 16 | 0.06 | 0.015 | |||
Ertapenem/clavulanate | 128 | 0.25 | 0.03 | 0.06 | 0.008 | 16 | 0.06 | 0.008 | |||
Ertapenem/APB | 8.0 | 0.008 | 0.015 | 0.03 | 0.008 | 0.5 | 0.03 | 0.008 | |||
Cefoxitin | 64 | 64 | 4.0 | 8.0 | 2.0 | ND | ND | 4 | |||
Ceftazidime | 256 | 16 | 16 | 32 | 0.06 | ND | ND | 0.25 | |||
Ceftazidime/clavulante | 16 | 32 | 0.5 | 0.5 | 0.06 | ND | ND | ND | |||
Cefepime | 32 | 4.0 | 16 | 16 | 0.03 | ND | ND | 0.03 | |||
Cefepime/clavulanate | 16 | 0.25 | 0.5 | 0.25 | 0.03 | ND | ND | ND | |||
Tigecycline** |
1.0 |
0.25 |
ND |
ND |
ND |
ND |
ND |
0.25 |
|||
Isolectric focusing results | |||||||||||
pI band†† |
5.4 + 6.7 + 7.6 |
5.4 + 6.7 + >9.0 |
6.7 |
6.7 |
None |
ND |
ND |
None |
|||
PCR results | |||||||||||
Β-lactamase | |||||||||||
blaKPC | + | + | + | + | – | + | – | ND | |||
blaampC | – | + CIT/ CMY | – | – | – | – | + CIT/ CMY | ND | |||
blaPER-2 | + | – | – | – | – | ND | ND | ND | |||
blaSHV | + | – | – | – | – | ND | ND | ND | |||
blaTEM-1 | + | + | – | – | – | ND | ND | ND |
*K.p., Klebsiella pneumoniae; C.f., Citrobacter freundii; E. coli, Escherichia coli; APB, 3-aminophenylboronic acid; IEF, isoelectric focusing; pI, isoelectric point; ND, not determined; +, positive; –, negative.
†M9204 transconjugant derived from K. pneumoniae M9171.
‡M9190 transconjugant derived from C. freundii M9169.
§Control strain producing KPC-2.
¶Control strain producing CMY-2.
#EDTA 0.4 mmol/L.
**Microdilution (JustOne, Trek Diagnostic Systems, Cleveland, OH, USA). Breakpoints according to US Food and Drug Administration (susceptible <2 μg/mL).
††Underlined pI bands indicated activity against third-generation cephalosporins