Discriminatory Detection of Inhibitor-Resistant β-Lactamases in Escherichia coli by Single-Strand Conformation Polymorphism-PCR

作者：Valérie Speldooren, Béate Heym, Roger Labia, Marie-Hélène Nicolas-Chanoine · 发表于：Antimicrobial Agents and Chemotherapy · 年份：1998 · DOI：10.1128/aac.42.4.879 · 被引用次数：72 · 研究领域：Antibiotic Resistance in Bacteria、Pharmaceutical and Antibiotic Environmental Impacts、Enterobacteriaceae and Cronobacter Research

Plasmid-mediated mechanisms, comprising TEM hyperproduction, TEM derivative production, and OXA production, lead to amoxicillin-clavulanic acid resistance in enterobacteria. The ability of the single-strand conformation polymorphism (SSCP)-PCR method to differentiate the genes encoding inhibitor-resistant beta-lactamases was evaluated with three bla(TEM) primer pairs. The bla(TEM) genes, which were known to be different on the basis of their nucleotide sequences (bla[TEM-1A], bla[TEM-1B], bla[TEM-2], bla[TEM-30], bla[TEM-32], and bla[TEM-35]), were identified as different by their electrophoretic mobilities. The bla(TEM-33), bla(TEM-34), bla(TEM-36), bla(TEM-37), bla(TEM-38), and bla(TEM-39) genes, whose sequence differences have been established by oligotyping, displayed different SSCP profiles for different fragments, suggesting genetic differences in addition to those defined by oligotyping. Confirmed by sequencing, these additional genetic events concerned silent mutations at certain positions and, notably, a G-->T transversion at position 1 of the -10 consensus sequence in bla(TEM-34), bla(TEM-36), bla(TEM-37), and bla(TEM-39). Applied to eight clinical isolates of Escherichia coli resistant to amoxicillin-clavulanic acid, the SSCP method detected TEM-1 in three strains and TEM-30, TEM-32, and TEM-35 in three other strains, respectively. A novel TEM derivative (TEM-58) was detected in another strain, and the deduced amino acid sequence showed two substitutions: Arg244Ser...