Open AccessSensitive and Rapid Detection of the New Delhi Metallo-Beta-Lactamase Gene by Loop-Mediated Isothermal Amplification
Author(s) -
Wei Liu,
Dayang Zou,
Yan Li,
Xuesong Wang,
Xiaoqing He,
Xiao Wei,
ChangLun Shao,
Xuelian Li,
Wei Shang,
Kaitao Yu,
Dawei Liu,
Yunmei Li,
Jing Guo,
Zhitao Yin,
Jing Yuan
Publication year - 2012
Publication title -
journal of clinical microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.349
H-Index - 255
eISSN - 1070-633X
pISSN - 0095-1137
DOI - 10.1128/jcm.06647-11
Subject(s) - loop mediated isothermal amplification , sputum , detection limit , biology , microbiology and biotechnology , plasmid , polymerase chain reaction , dna , chemistry , chromatography , gene , medicine , genetics , tuberculosis , pathology
New Delhi metallo-β-lactamase 1 (NDM-1), which is associated with resistance to carbapenem, was first reported in 2008. A sensitive and rapid molecular assay to detect the plasmidbla NDM-1 in clinical isolates is needed to control its spread. We describe a loop-mediated isothermal amplification (LAMP) assay for the rapid detection ofbla NDM-1 from pure culture and sputum, urine, and fecal samples. Eight sets of primers were designed to recognize six or eight distinct sequences on targetbla NDM-1 , and one set was selected as the most appropriate set of primers for its rapid detection. The specificity and sensitivity of the primers in the LAMP reactions forbla NDM-1 detection were determined. The sensitivity of the LAMP assay forbla NDM-1 detection in sputum, urine, and fecal samples was also tested. Two methods, namely, monitoring of turbidity and addition of calcein to the reaction tube, were used to determine negative and positive results. The results showed that target DNA was amplified and visualized by the two detection methods within 70 min at an isothermal temperature of 65°C. The sensitivity of LAMP, with a detection limit of 10.70 pg/μl DNA, was 100-fold greater than that of PCR. Thirteen infection bacterial strains withoutbla NDM-1 were selected for testing of specificity, and the results of the amplification were negative, which showed that the primers had good levels of specificity. The LAMP method reported here is demonstrated to be a potentially valuable means for the detection ofbla NDM-1 and rapid clinical diagnosis, being fast, simple, and low in cost.