Repeatability and reproducibility of the wzi high resolution melting-based clustering analysis for Klebsiella pneumoniae typing.

High resolution melting (HRM) is a fast closed-tube method for nucleotide variant scanning applicable for bacterial species identification or molecular typing. Recently a novel HRM-based method for Klebsiella pneumoniae typing has been proposed: it consists of an HRM protocol designed on the capsular wzi gene and an HRM-based algorithm of strains clustering. In this study, we evaluated the repeatability and reproducibility of this method by performing the HRM typing of a set of K. pneumoniae strains, on three different instruments and by two different operators. The results showed that operators do not affect melting temperatures while different instruments can. Despite this, we found that strain clustering analysis, performed using MeltingPlot separately on the data from the three instruments, remains almost perfectly consistent. The HRM method under study resulted highly repeatable and thus reliable for large studies, even when several operators are involved. Furthermore, the HRM clusters obtained from the three different instruments were highly conserved, suggesting that this method could be applied in multicenter studies, even if different instruments are used.