OXA-28, an extended-spectrum variant of OXA-10 beta-lactamase from Pseudomonas aeruginosa and its plasmid- and integron-located gene - PubMed (original) (raw)

OXA-28, an extended-spectrum variant of OXA-10 beta-lactamase from Pseudomonas aeruginosa and its plasmid- and integron-located gene

L Poirel et al. Antimicrob Agents Chemother. 2001 Feb.

Abstract

Pseudomonas aeruginosa ED-1, isolated from a pulmonary brush of a patient hospitalized in a suburb of Paris, France, was resistant to ceftazidime and of intermediate susceptibility to ureidopenicillins and to cefotaxime. Cloning and expression of the beta-lactamase gene content of this isolate in Escherichia coli DH10B identified a novel OXA-10 variant, OXA-28, with a pI value of 8.1 and a molecular mass of 29 kDa. It differed from OXA-10 by 10 amino acid changes and from OXA-13 and OXA-19 by 2 amino acid changes, including a glycine instead of tryptophan at position 164, which is likely involved in its resistance to ceftazidime. Like OXA-11, -14, -16, and -19 and as opposed to OXA-17, OXA-28 predominantly compromised ceftazidime and had only marginal effect on the MICs of aztreonam and cefotaxime in P. aeruginosa. Once expressed in E. coli, OXA-28 raised the MIC of ceftazidime to a much higher level than those of amoxicillin, cephalothin, and cefotaxime (128, 16, 8, and 4 microg/ml, respectively). OXA-28 beta-lactamase had a broad spectrum of activity, including ceftazidime. Its activity was partially antagonized by clavulanic acid (50% inhibitory concentration, 10 microM) and NaCl addition. The oxa28 gene cassette was inserted in the variable region of a class 1 integron, In57, immediately downstream of an amino 6'-N-acetyltransferase gene cassette, aac(6')Ib. The structures of the integrons carrying either oxa28, oxa13, or oxa19 gene cassettes were almost identical, suggesting that they may have derived from a common ancestor as a result of the common European origin of the P. aeruginosa isolates. In57 was located on a self-transferable plasmid of ca. 150 kb that was transferred from P. aeruginosa to P. aeruginosa.

PubMed Disclaimer

Figures

FIG. 1

FIG. 1

Nucleotide sequence of 2,254 bp of recombinant plasmid pDG-1 containing the _bla_OXA-28 coding region and part of its integron, In57. The deduced amino acid sequence is designated in single-letter code below the nucleotide sequence. The slash indicates the putative clevage site for the leader peptide for the mature OXA-28 β-lactamase. Underlined amino acid sequences are those conserved for the oxacillinase family and are numbered according to DBL numbering (3). The start codons of intI1, _bla_OXA-28, and aac(6′)Ib are indicated by horizontal arrows, and their stop codons are indicated by asterisks. The −35 and −10 sequences of the promoters Pc, P2, and Pint are underlined. The conserved core and inverse core sites located at the oxa28 and aac(6′)Ib cassette boundaries are boxed and the composite 59-base elements are italicized. The additional base of the 59-base element of the oxa28 gene cassette as compared to the 59-base element of the oxa19 gene cassette is indicated by a square below the 59-base element of the oxa28 gene cassette. The cassette boundaries are indicated by vertical arrows. The left part of the attI1 site is underlined with a dotted line.

Similar articles

Cited by

References

    1. Chen H Y, Yuan M, Livermore D M. Mechanisms of resistance to β-lactam antibiotics amongst Pseudomonas aeruginosa isolates collected in the UK in 1993. J Med Microbiol. 1995;43:300–309. - PubMed
    1. Collis C M, Hall R M. Expression of antibiotic resistance gene in the integrated cassettes of integrons. Antimicrob Agents Chemother. 1995;39:155–162. - PMC - PubMed
    1. Couture F, Lachapelle J, Levesque R C. Phylogeny of LCR-1 and OXA-5 with class A and class D β-lactamases. Mol Microbiol. 1992;6:1693–1705. - PubMed
    1. Dale J W, Godwin D, Mossakowska D, Stephenson P, Wall S. Sequence of the OXA-2 β-lactamase: comparison with other penicillin-reactive enzymes. FEBS Lett. 1985;191:39–44. - PubMed
    1. Danel F, Hall L M C, Duke B, Gur D, Livermore D M. OXA-17, a further extended-spectrum variant of OXA-10 β-lactamase isolated from Pseudomonas aeruginosa. Antimicrob Agents Chemother. 1999;43:1362–1366. - PMC - PubMed

Publication types

MeSH terms

Substances

LinkOut - more resources