Differential regulation of L1 and L2 β-lactamase expression in Stenotrophomonas maltophilia

• Published in: Journal of antimicrobial chemotherapy 2002-02, Vol.49 (2), p.387-389
• Main Authors: Avison, Matthew B., Higgins, Catherine S., Ford, Peter J., von Heldreich, Charlotte J., Walsh, Timothy R., Bennett, Peter M.
• Format: Article
• Language: English
• Subjects: Antibacterial agents; Antibiotics. Antiinfectious agents. Antiparasitic agents; Bacteriology; beta-Lactamases - biosynthesis; beta-Lactamases - genetics; Biological and medical sciences; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Enzymologic - genetics; Genetics; Humans; Medical sciences; Metabolism. Enzymes; Microbiology; Mutation; Pharmacology. Drug treatments; Stenotrophomonas maltophilia - enzymology; Stenotrophomonas maltophilia - genetics; Stenotrophomonas maltophilia - isolation & purification
• ISSN: 0305-7453; 1460-2091; 1460-2091
• DOI: 10.1093/jac/49.2.387

It has been reported that Stenotrophomonas maltophilia L1 and L2 β-lactamase expression is coordinated. We have isolated S. maltophilia mutants where (i) L1 is constitutively hyper-expressed and L2 is inducible; (ii) L2 is hyper-expressed and L1 is inducible; and (iii) L1 and L2 are constitutively hyper-expressed. The frequency of isolating type 1 and 2 mutants is c. 10−7, indicating that promoter mutations are probably not involved and providing strong evidence that L1 and L2 expression is not, after all, coordinated. The frequency of isolating type 3 mutants is c. 10−9, however, implying that there is a significant overlap between the regulatory mechanisms.