IMP-1 and a Novel Metallo-β-Lactamase, VIM-6, in Fluorescent Pseudomonads Isolated in Singapore

Abstract

Four carbapenem-resistant Pseudomonas spp. were isolated from patients in Singapore. One Pseudomonas putida isolate contained a bla IMP-1 identical to that first described in Japan. The sequence of a variant bla IMP-1 in Pseudomonas fluorescens contained four silent mutations compared with the original sequence. The remaining P. putida isolates contained bla VIM-6 , a novel VIM gene variant.

Metallo-β-Lactamases: the Quiet before the Storm?

“…These isolates were highly resistant to ␤-lactams, with MICs of Ͼ32 g/ml for imipenem and meropenem, Ͼ256 g/ml for ceftazidime, and 128 g/ml for aztreonam. VIM-6 differs from VIM-2 by two amino acid changes (glutamine/arginine at position 59 and asparagine/serine at position 165) and from VIM-3 by only one amino acid (75).…”

“…The P. aeruginosa isolate in which bla VIM-5 has been identified was resistant to all ␤-lactams, including aztreonam. ␤-Lactamase VIM-6 was identified from two P. putida isolates from Singapore (75). These isolates were highly resistant to ␤-lactams, with MICs of Ͼ32 g/ml for imipenem and meropenem, Ͼ256 g/ml for ceftazidime, and 128 g/ml for aztreonam.…”

Clonal Spread of IMP-1-Producing Pseudomonas aeruginosa in Two Hospitals in Singapore

“…pore (4). The immediate flanking regions of bla IMP-1 in strains DU8622/00, DM14158/00, DU10114/00, and DU32495/00 were identical to that of an integron sequence containing bla IMP-1 in GenBank (accession number AB104852.1), showing that these genetic elements are probably important in the spread of bla IMP-1 .…”

Molecular Characterization of a β-Lactamase Gene, bla GIM-1 , Encoding a New Subclass of Metallo-β-Lactamase

“…For many years, the occurrence of IMP-1-producing bacteria was confined to Japan. More recently, however, IMP-1 and IMP-variant enzymes have been reported from many other countries and across four continents (6,9,12,13,24,27). Since the emergence of IMP-1, two other subclasses of clinically relevant M␤Ls have been described: the VIM series (15) and SPM-1 (29).…”

“…Since the emergence of IMP-1, two other subclasses of clinically relevant M␤Ls have been described: the VIM series (15) and SPM-1 (29). VIM variants are now found throughout the world as well (2,13,17,20,21,30,32,34,35), whereas SPM-1 thus far seems to be restricted to Brazil.We characterize here a novel subclass of Ambler class B enzyme, GIM-1, which is encoded by a gene cassette located in the first position of a class 1 integron. The carbapenem-resistant P. aeruginosa clinical isolates that produce GIM-1 were recovered in Germany and were detected by The SENTRY Antimicrobial Surveillance Program in 2002.…”