ZIWR Weekly SEMINAR
Wednesday, June 13th, 2018 at 13:15
Seminar room, old administration building
Whole Genome Sequence (WGS) Analysis of Legionella pneumophila (Lp) for Investigation of Legionnaires' Disease (LD)
Prof. Jacob Moran-Gilad
School of Public Health, Faculty of Health Sciences, BGU;
& Public Health Services, Ministry of Health, Jerusalem, Israel
Sequence-based typing (SBT) has dramatically improved LD investigation. We have recently shown the diversity of Lp in Israel and that ST1 is the leading molecular type locally implicated in LD. Microbial WGS is a promising modality for cluster investigations but analysis methods are neither standardised, nor agreed. We studied WGS applicability for LD investigation by calling differences in core genome alleles (extended MLST approach). We devised a 1,521 core genome loci-based typing scheme. Analysis of published outbreak strains generated a nearly identical strain clustering as compared to SNP mapping. When applied to cases of paediatric LD in Israel as well as analysis of a large LD outbreak in Germany, phylogenetic analysis was able to differentiate between epidemiologically related and unrelated strains and even provided evidence for concurrent infection with multiple ST1 strains. Thus, cgMLST analysis was readily achievable, identified clustered strains and differentiated those from unrelated strains within the same clonal complex. The cgMLST methods is now being refined by an international Working Group and is expected to be adopted as the global standardised scheme for Lp typing.