title: Use of the ligase detection reaction-polymerase chain reaction to identify point mutations in extended-spectrum beta-lactamases.
abstract: The aim of this study was to detect point mutations in extended-spectrum beta-lactamase (ESBL) genes in a background of wild-type (non-ESBL-producing) bacteria using a highly sensitive and specific method developed for this purpose. The ligase detection reaction-polymerase chain reaction (LDR-PCR) method was used to test different ESBL-producing strains and clinical isolates for a specific point mutation in the bla SHV-ESBL gene (glycine to serine mutation at position 238) and was compared with the commercially available E test ESBL (AB Biodisk, Sweden). Nine of the 40 clinical isolates tested were positive for the bla SHV-ESBL point mutation when tested by the LDR-PCR method but negative when tested by the E test. In contrast to the E test or other molecular genetic tests, the LDR-PCR method is able to identify a single bacterium with a point mutation in a background of 100,000 wild-type (non-ESBL-producing) bacteria.
authors.affiliation: Institute of Microbiology, Kantonsspital Aarau, Switzerland. Christoph.Niederhauser@KSA.ch
authors.forename: C
authors.initials: C
authors.lastname: Niederhauser
authors.forename: L
authors.initials: L
authors.lastname: Kaempf
authors.forename: I
authors.initials: I
authors.lastname: Heinzer
mesh_terms: D019943:Amino Acid Substitution; D004755:Enterobacteriaceae / Q000201:enzymology / Q000235:genetics*; D004756:Enterobacteriaceae Infections / Q000382:microbiology; D005798:Genes, Bacterial; D006801:Humans; D022521:Ligase Chain Reaction; D017354:Point Mutation; D016133:Polymerase Chain Reaction; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D001618:beta-Lactamases