These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Emergence of oxacillinase-mediated resistance to imipenem in Klebsiella pneumoniae.
    Author: Poirel L, Héritier C, Tolün V, Nordmann P.
    Journal: Antimicrob Agents Chemother; 2004 Jan; 48(1):15-22. PubMed ID: 14693513.
    Abstract:
    Klebsiella pneumoniae strain 11978 was isolated in Turkey in 2001 and was found to be resistant to all beta-lactams, including carbapenems. Cloning and expression in Escherichia coli identified five beta-lactamases, including two novel oxacillinases. The beta-lactamase OXA-48 hydrolyzed imipenem at a high level and was remotely related (less than 46% amino acid identity) to the other oxacillinases. It hydrolyzed penicillins and imipenem but not expanded-spectrum cephalosporins. The bla(OXA-48) gene was plasmid encoded and not associated with an integron, in contrast to most of the oxacillinase genes. An insertion sequence, IS1999, was found immediately upstream of bla(OXA-48). Another plasmid that encoded a second oxacillinase gene, bla(OXA-47), located inside a class 1 integron was identified in K. pneumoniae 11978. OXA-47 had a narrow spectrum of hydrolysis activity and did not hydrolyze ceftazidime or imipenem, as is found for the beta-lactamase (OXA-1) to which it is related. In addition, beta-lactamases TEM-1 and SHV-2a were expressed from the same K. pneumoniae isolate. Analysis of the outer membrane proteins of this isolate revealed that it lacked a porin of ca. 36 kDa. Thus, the high-level resistance to beta-lactams of this clinical isolate resulted from peculiar beta-lactamases and modification of outer membrane proteins.
    [Abstract] [Full Text] [Related] [New Search]