Transferable class C beta-lactamases in Escherichia coli strains isolated in Greek hospitals and characterization of two enzyme variants (LAT-3 and LAT-4) closely related to Citrobacter freundii AmpC beta-lactamase.
Among 2133 isolates of Escherichia coli obtained during 1996 from 10 Greek hospitals, 63 (3%) were resistant to cefoxitin. Typing by ERIC2-PCR indicated that the cefoxitin-resistant (FOXr) isolates were distinct. beta-Lactamase studies and hybridization experiments showed that most strains produced beta-lactamases related to the AmpC chromosomal cephalosporinase of Citrobacter freundii. The enzymes were encoded by similar non-self-transmissible plasmids. The bla genes encoding two beta-lactamases (LAT-3 and LAT-4) with isoelectric points 8.9 and 9.4, respectively, were cloned and sequenced. The deduced amino acid sequences displayed a high degree of homology (>95%) with the AmpC beta-lactamase of C. freundii. The patterns of resistance to beta-lactams of the FOXr E. coli depended on the quantity of class C enzymes and the simultaneous expression of other beta-lactamases. In a few isolates a 36 kDa outer-membrane protein, presumably a porin, was not expressed at detectable quantities. These isolates were resistant to cefoxitin, and their susceptibility to the other beta-lactams tested was not significantly decreased.
Gazouli
M
M
Department of Bacteriology, Hellenic Pasteur Institute, Athens, Greece.
Tzouvelekis
L S
LS
Vatopoulos
A C
AC
Tzelepi
E
E
D000595:Amino Acid Sequence; D001425:Bacterial Outer Membrane Proteins / Q000378:metabolism; D001426:Bacterial Proteins; D001483:Base Sequence; D002440:Cefoxitin / Q000627:therapeutic use; D002513:Cephamycins / Q000627:therapeutic use; D016971:Citrobacter freundii / Q000201:enzymology* / Q000235:genetics; D003001:Cloning, Molecular; D004352:Drug Resistance, Microbial; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D029968:Escherichia coli Proteins; D018014:Gene Transfer Techniques; D006115:Greece; D006801:Humans; D006868:Hydrolysis; D007525:Isoelectric Focusing; D007527:Isoenzymes / Q000378:metabolism; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D010957:Plasmids; D001618:beta-Lactamases / Q000235:genetics / Q000378:metabolism*
D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D002513:Cephamycins; D029968:Escherichia coli Proteins; D007527:Isoenzymes; D002440:Cefoxitin; C117095:beta-lactamase LAT-3 protein, E coli; C117096:beta-lactamase LAT-4 protein, E coli; C048795:AmpC beta-lactamases; D001618:beta-Lactamases