The Staphylococcus qacH gene product: a new member of the SMR family encoding multidrug resistance.
FEMS Microbiol Lett, 1998/6/01;163(1):49-56.
Heir E[1], Sundheim G, Holck AL
Affiliations
PMID: 9631545
Impact factor: 2.82
Abstract
The prevalence of disinfectant-resistant food-related microorganisms is of concern to the food industry. The Staphylococcus saprophyticus strain ST2H6 isolated from a poultry processing plant contained a 2.4-kb plasmid (p2H6) harbouring qacH, which encodes resistance to disinfectants based on quaternary ammonium compounds. The complete p2H6 nucleotide sequence revealed an open reading frame encoding a putative protein of 107 amino acid residues with strong similarity to members of the small multidrug resistance protein family. QacH also conferred high-level ethidium bromide resistance and low-level proflavine resistance and thus differed phenotypically from the similar proteins Smr and QacG. Fluorimetry indicated that the high-level ethidium bromide resistance was due to improved efflux energised by the proton motive force. Site-directed mutagenesis substituting the Asp-24 residue with Glu-24 had no effect on resistance characteristics. An additional open reading frame on p2H6 encoded a putative protein with similarity to rolling circle replication proteins.
MeSH terms
Amino Acid Sequence; Animals; Antiporters; Bacterial Proteins; Base Sequence; Benzalkonium Compounds; Carrier Proteins; Cloning, Molecular; Disinfectants; Drug Resistance, Multiple; Escherichia coli Proteins; Ethidium; Membrane Proteins; Membrane Transport Proteins; Microbial Sensitivity Tests; Molecular Sequence Data; Mutagenesis, Site-Directed; Norway; Plasmids; Poultry; Proflavine; Sequence Analysis, DNA; Sequence Homology, Amino Acid; Staphylococcus
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