Broad resistance due to plasmid-mediated AmpC beta-lactamases in clinical isolates of Escherichia coli.
Escherichia coli that produce plasmid-mediated AmpC beta-lactamases are rare in the United States. The clinical features associated with infection with these organisms have not been well described. We identified 2 clinical isolates of E. coli that produced the plasmid-mediated AmpC enzyme beta-lactamase CMY-2. These organisms were recovered from urine specimens and were resistant to ceftazidime, ceftriaxone, and cefepime. One isolate was resistant to ertapenem but susceptible to imipenem and meropenem; the other was susceptible to imipenem, meropenem, and ertapenem. One of the 2 infected patients did not require specific therapy; the other required imipenem for cure. The presence of the CMY-2 beta-lactamase was confirmed by DNA sequencing. Hybridization studies confirmed that the bla(CMY-2) gene was on a plasmid in both isolates; in one of them, the probe also hybridized with chromosomal DNA. Infection with plasmid-mediated AmpC beta-lactamases in E. coli in the United States may be associated with treatment failure, and these strains may become a serious nosocomial threat.
Odeh
R
R
University of Illinois, Chicago, IL 60612, USA.
Kelkar
S
S
Hujer
A M
AM
Bonomo
R A
RA
Schreckenberger
P C
PC
Quinn
J P
JP
D000328:Adult; D001426:Bacterial Proteins; D015153:Blotting, Western; D018550:Cephalosporin Resistance / Q000235:genetics; D003227:Conjugation, Genetic / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics* / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000188:drug therapy; D029968:Escherichia coli Proteins / Q000032:analysis / Q000235:genetics / Q000276:immunology; D005260:Female; D005784:Gene Amplification; D006801:Humans; D015378:Imipenem / Q000378:metabolism / Q000627:therapeutic use; D008297:Male; D008826:Microbial Sensitivity Tests; D009693:Nucleic Acid Hybridization; D010957:Plasmids / Q000235:genetics* / Q000378:metabolism; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D018440:beta-Lactam Resistance / Q000235:genetics*; D001618:beta-Lactamases / Q000032:analysis / Q000235:genetics* / Q000276:immunology / Q000378:metabolism*
D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D015378:Imipenem; C103022:beta-lactamase CMY-2; C048795:AmpC beta-lactamases; D001618:beta-Lactamases