Objectives Fast and adequate detection of extended-spectrum ß-lactamases (ESBLs) is crucial for infection control measures and the choice of antimicrobial therapy. The aim of this study was to develop and evaluate a novel ESBL assay using ligation-mediated amplification combined with microarray analysis to detect the most prevalent ESBLs in Enterobacteriaceae: TEM, SHV and CTX-M. Methods Analysis of the Lahey database revealed that the vast majority of TEM and SHV ESBLs differ from non-ESBL variants in three amino acid positions. TEM ESBLs have at least one of the following amino acid substitutions: R164S/H/C, G238D/N/S and E104K. In SHV ESBLs, one or more of the following substitutions is observed: D179A/N/G, G238S/A and E240K. Oligonucleotide probes were designed to detect these substitutions, covering 95% of ESBL TEM variants and 77% of ESBL SHV variants. In addition, probes were designed to distinguish between CTX-M groups 1, 2, 9 and 8/25. For evaluation of the assay, 212 Enterobacteriaceae isolates with various ß-lactamases were included (n¿=¿106 ESBL positive). Results The sensitivity of the microarray was 101/106 (95%; 95% CI 89%–98%), and the specificity 100% (95% CI 97%–100%) using molecular characterization of ESBLs by PCR and sequencing as reference. Assay performance time was 8 h for 36 isolates. Conclusions This novel commercially available DNA microarray system may offer an attractive option for rapid and accurate detection of CTX-M, TEM and SHV ESBL genes in Enterobacteriaceae in the clinical laboratory.
Cohen Stuart, J., Dierikx, C. M., Al Naiemi, N., Karczmarek, A., Hoek, A., Vos, P., Fluit, A. C., Scharringa, J., Duim, B., Mevius, D. J., & Leverstein-van Hall, M. A. (2010). Rapid detection of TEM, SHV and CTX-M extended-spectrum ß-lactamases in Enterobacteriaceae using ligation-mediated amplification with microarray analysis. Journal of Antimicrobial Chemotherapy, 65(7), 1377-1381. https://doi.org/10.1093/jac/dkq146