Imipenem resistance in clinical isolates of Proteus mirabilis associated with alterations in penicillin-binding proteins.
Two strains of Proteus mirabilis, IpR1 and IpR2, resistant to both imipenem and mecillinam, but susceptible to other beta-lactams were isolated from blood cultures of patients who had been treated with imipenem. Strain IpR1 was isolated in the same sample as a P. mirabilis IpS1 which was susceptible to imipenem and mecillinam. Strains IpR1 and IpR2 did not produce a beta-lactamase and their outer membrane protein profiles were similar to those of IpS1 and P. mirabilis ATCC 29906. Electrophoretic profiles of penicillin-binding proteins (PBPs) showed a decrease in PBP 1A of strains IpR1 and IpR2 compared with IpS1 and ATCC 29906. Competition experiments revealed a decrease in affinity of PBP 2 for imipenem from strain IpR1. These findings suggest that imipenem resistance in P. mirabilis might result from altered PBPs, as reported for Acinetobacter baumanii and Pseudomonas aeruginosa.
Laboratoire de Bactériologie, Hôpital Universitaire du Bocage, Dijon, France.
C
C
Neuwirth
E
E
Siébor
J M
JM
Duez
A
A
Péchinot
A
A
Kazmierczak
D000560:Amdinocillin / Q000494:pharmacology; D001425:Bacterial Outer Membrane Proteins / Q000378:metabolism; D001426:Bacterial Proteins; D002352:Carrier Proteins / Q000378:metabolism*; D004352:Drug Resistance, Microbial; D004591:Electrophoresis, Polyacrylamide Gel; D006602:Hexosyltransferases; D006801:Humans; D015378:Imipenem / Q000494:pharmacology*; D007525:Isoelectric Focusing; D002267:Muramoylpentapeptide Carboxypeptidase / Q000378:metabolism*; D010403:Penicillin Resistance; D046915:Penicillin-Binding Proteins; D010406:Penicillins / Q000494:pharmacology; D010458:Peptidyl Transferases; D011512:Proteus Infections / Q000382:microbiology; D011513:Proteus mirabilis / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D013845:Thienamycins / Q000494:pharmacology*; D001618:beta-Lactamases / Q000378:metabolism
D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D002352:Carrier Proteins; D046915:Penicillin-Binding Proteins; D010406:Penicillins; D013845:Thienamycins; D015378:Imipenem; D010458:Peptidyl Transferases; D006602:Hexosyltransferases; D002267:Muramoylpentapeptide Carboxypeptidase; D001618:beta-Lactamases; D000560:Amdinocillin