PCR typing of genetic determinants for metallo-beta-lactamases and integrases carried by gram-negative bacteria isolated in Japan, with focus on the class 3 integron.
From January 2001 to December 2002, 587 strains of gram-negative bacterial isolates demonstrating resistance to ceftazidime and a combination of sulbactam and cefoperazone were subjected to a disk diffusion screening test using sodium mercaptoacetic acid; 431 strains (73.4%) appeared to produce metallo-beta-lactamase (MBL). Of these 431 strains, 357 were found by PCR to carry genes for IMP-1 type MBL (bla(IMP-1)), while only 7 and 67 strains carried the IMP-2 gene (bla(IMP-2)) and the VIM-2 gene (bla(VIM-2)), respectively. Neither VIM-1 nor SPM-1 type MBL genes were found among the strains tested. Of 431 strains, 427 carried the intI1 gene, and 4 strains carrying both the intI1 and intI3 genes were reidentified as Pseudomonas putida harboring bla(IMP-1). Of these four P. putida strains, three strains and one strain, respectively, were separately isolated from two hospitals located in the same prefecture, and the three strains showed very similar pulsed-field gel electrophoresis patterns. Of 357 bla(IMP-1) carriers, 116, 53, 51, 47, and 30 strains were identified as Pseudomonas aeruginosa, Alcaligenes xylosoxidans, P. putida/fluorescens, Serratia marcescens, and Acinetobacter baumannii, respectively. Four strains carrying bla(IMP-2) were reidentified as P. putida. Sixty-three P. aeruginosa strains and four P. putida strains carried bla(VIM-2). Of 427 intI1-positive strains, 180, 53, 51, 47, and 35 were identified as P. aeruginosa, A. xylosoxidans, P. putida/fluorescens, S. marcescens, and A. baumannii, respectively. In the present study, it was confirmed that strains carrying bla(IMP-1) with a class 1 integron are the most prevalent type in Japan, although several intI3 carriers have also been identified sporadically in this country.
Shibata
Naohiro
N
Department of Bacterial Pathogenesis and Infection Control, National Institute of Infectious Diseases, Tokyo, Japan. nsbt@nih.go.jp
Doi
Yohei
Y
Yamane
Kunikazu
K
Yagi
Tetsuya
T
Kurokawa
Hiroshi
H
Shibayama
Keigo
K
Kato
Haru
H
Kai
Kumiko
K
Arakawa
Yoshichika
Y
D000368:Aged; D001483:Base Sequence; D002544:Cerebral Infarction / Q000382:microbiology; D017931:DNA Primers; D016521:Electrophoresis, Gel, Pulsed-Field; D005260:Female; D006090:Gram-Negative Bacteria / Q000145:classification / Q000201:enzymology / Q000235:genetics* / Q000302:isolation & purification; D016905:Gram-Negative Bacterial Infections / Q000382:microbiology; D006801:Humans; D019426:Integrases / Q000235:genetics*; D007564:Japan; D008297:Male; D016133:Polymerase Chain Reaction / Q000379:methods*; D011471:Prostatic Neoplasms / Q000382:microbiology; D016958:Pseudomonas putida / Q000201:enzymology / Q000235:genetics; D001618:beta-Lactamases / Q000235:genetics*
D017931:DNA Primers; D019426:Integrases; D001618:beta-Lactamases