Methods: The LAMP-based assay was evaluated using reference strains having each of six ß-lactamase genes; including Klebsiella pneumoniae, Escherichia coli, P. aeruginosa, and Acinetobacter bereziniae. A collection of 47 clinical P. aeruginosa isolates, previously fully characterized by next-generation sequencing (NGS) were used for evaluation of our new LAMP method. The results were compared with those obtained using the conventional PCR method (J Antimicrob Chemother 2012).
Results: The LAMP assay was able to detect as few as 10 copies of the gene in a sample, which was comparable to the conventional PCR method. The LAMP assay correctly detected ß-lactamase genes in all collected clinical isolates (47/47). In contrast, PCR did not detect four IMP ß-lactamase genes (IMP-4, 13, 15 and 18) in the clinical isolates (43/47). Among those PCR failed to detect, one isolate was susceptible to carbapenem and three were carbapenem-resistant isolates. Compared to the NGS results; the sensitivity and specificity of the IMP ß-lactamase genes LAMP assay were 100% (4/4) and 100% (43/43), whereas those of the conventional PCR were 0% (0/4) and 100% (43/43).
Conclusion: The established LAMP assay proved to be an appropriate tool for the detection of six different ß-lactamase genes. The test demonstrated higher sensitivity and similar specificity compared with conventional PCR. The LAMP needs the minimum technology for the assay. The test would be useful for routine simple confirmation of ß-lactamase producing P. aeruginosa.
Kaneka Co. Ltd:
P. Kilgore, None
D. W. Kim, None
T. Adachi, Kaneka Co. Ltd: Employee , Salary
R. Mclaughlin, Astrazeneca: Employee , Salary
H. Gardner, Astrazeneca: Employee , Salary
A. Salim, None
S. Hayakawa, Kaneka Co. Ltd: Collaborator , Research grant
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