BLAI AND BLAR1 REGULATE BETA-LACTAMASE AND PBP 2A PRODUCTION IN METHICILLIN-RESISTANT STAPHYLOCOCCUS-AUREUS

被引:121
作者
HACKBARTH, CJ
CHAMBERS, HF
机构
[1] UNIV CALIF SAN FRANCISCO, SAN FRANCISCO, CA 94143 USA
[2] SAN FRANCISCO GEN HOSP, SAN FRANCISCO, CA 94110 USA
关键词
D O I
10.1128/AAC.37.5.1144
中图分类号
Q93 [微生物学];
学科分类号
071005 ; 100705 ;
摘要
For Staphylococcus aureus, it is hypothesized that two genes located upstream of the beta-lactamase gene, blaZ, are required for the inducible expression of beta-lactamase. blaR1 is predicted to encode a signal-transducing membrane protein, and blaI is predicted to encode a repressor protein. These same two genes may also regulate the production of penicillin-binding protein 2a (PBP 2a), a protein essential for expression of methicillin resistance. To confirm that these two genes encode products that can control both beta-lactamase and PBP 2a production, blaI, blaR1, and blaZ with a 150-nucleotide deletion at the 3' end were subcloned from a 30-kb staphylococcal beta-lactamase plasmid and three beta-lactamase-negative strains of methicillin-resistant S. aureus were transformed with the recombinant plasmid containing that insert. The production of PBP 2a and a nonfunctional beta-lactamase was detected by fluorography and by immunoblots with polyclonal antisera directed against each of the proteins. Whereas the parent strains did not produce beta-lactamase and constitutively produced PBP 2a, PBP 2a and a truncated beta-lactamase were now inducible in the transformants. Therefore, two plasmid-derived genes regulate the production of both PBP 2a and beta-lactamase.
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页码:1144 / 1149
页数:6
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