Legionnaires' disease (LD) is a significant public health threat in community and hospital settings, caused by Legionella pneumphila (Lp). Control of LD involves routine inspection of drinking water and application of preventive measures to decrease risk. The accurate detection, identification and typing of Lp are crucial but remains a challenge in many settings. A molecular epidemiology laboratory for Lp has recently been established at the MOH to support efforts coordinated by a nominated national programme for LD control. The successfully applied methods were developed in collaboration with international partners and include: (1) regulation of Lp strain referral; (2) a national strain repository; (3) mip based molecular Lp speciation; (4) multiplex qPCR assay for clinical and environmental detection of Lp; (5) a sequence-based typing (SBT) scheme in collaboration with ESGLI; (6) direct typing capabilities applied on clinical material; and (7) application of whole genome sequencing for deep analysis of Lp. During 2013, molecular epidemiology studies have supported the investigation of 20 LD cases in Israel by typing of clinical and/or environmental strains. Analysis of a sample of 202 environmental strains recovered from healthcare, community and recreational settings revealed sg.1/ST1 as the most common phenon (44%), followed by sg.3/ST338 (11%) and sg.3/ST87 (11%). Notably, novel STs were detected in 6% of cases and deposited in international database. The establishment of molecular Lp analysis and introduction of sequence-based and genomic approaches has shed light on local Lp strain diversity and greatly enhanced public health tools for LD control in Israel.
