PCR detection of metallo-beta-lactamase gene (blaIMP) in gram-negative rods resistant to broad-spectrum beta-lactams.
We applied PCR to the rapid detection of the metallo-beta-lactamase gene, blaIMP, in clinically isolated gram-negative rods. A total of 54 high-level ceftazidime-resistant strains (MICs, > 128 micrograms/ml) were subjected to PCR analyses with the blaIMP-specific primers, since the blaIMP-bearing clinical isolates tested in our previous study always demonstrated high-level resistance to ceftazidime. Twenty-two blaIMP-positive strains including 9 Pseudomonas aeruginosa, 9 Serratia marcescens, 2 Alcaligenes xylosoxidans, 1 Pseudomonas putida, and 1 Klebsiella pneumoniae strains were newly identified from 18 different hospitals in Japan. These strains were mostly isolated from urine samples and showed high-level resistance to almost every cephem, while their levels of resistance to carbapenems were diverse. The PCR analyses with novel integrase gene-specific (intI3) and acc(6')-Ib gene-specific primers suggested that the integron structure found in a large plasmid harbored by S. marcescens AK9373 was also well conserved among blaIMP-positive strains. These results imply that the blaIMP gene cassettes have been dispersing into various gram-negative rods with the help of the newly identified integron element. Thus, the PCR-aided rapid detection will be helpful for the early recognition of emerging blaIMP-positive clinical isolates which demonstrate consistent resistance to beta-lactams.
Senda
K
K
Department of Bacteriology, Nagoya University School of Medicine, Japan.
Arakawa
Y
Y
Ichiyama
S
S
Nakashima
K
K
Ito
H
H
Ohsuka
S
S
Shimokata
K
K
Kato
N
N
Ohta
M
M
D000421:Alcaligenes / Q000187:drug effects / Q000201:enzymology / Q000235:genetics; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins; D001431:Bacteriological Techniques; D001483:Base Sequence; D015780:Carbapenems / Q000494:pharmacology; D002442:Ceftazidime / Q000494:pharmacology; D003428:Cross Infection / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology; D017931:DNA Primers / Q000235:genetics; D004352:Drug Resistance, Microbial / Q000235:genetics; D005798:Genes, Bacterial; D006090:Gram-Negative Bacteria / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics*; D016905:Gram-Negative Bacterial Infections / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology; D006801:Humans; D007564:Japan / Q000453:epidemiology; D007711:Klebsiella pneumoniae / Q000187:drug effects / Q000201:enzymology / Q000235:genetics; D017720:Molecular Epidemiology; D016133:Polymerase Chain Reaction / Q000379:methods*; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000201:enzymology / Q000235:genetics; D016958:Pseudomonas putida / Q000187:drug effects / Q000201:enzymology / Q000235:genetics; D012706:Serratia marcescens / Q000187:drug effects / Q000201:enzymology / Q000235:genetics; D001618:beta-Lactamases / Q000235:genetics*
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D015780:Carbapenems; D017931:DNA Primers; D002442:Ceftazidime; D001618:beta-Lactamases