Application of Sequence Based Typing (SBT) Technique to Typing Strains of Legionella spp.: Development of an Environmental Risk Map

The main purpose of my PhD is the assessment of the environmental prevalence of Legionella spp. in artificial aquatic environments, considered a habitat at major risk of proliferation, in order to elaborate a risk map. The water distribution system for its characteristics: material of pipelines, aging of network, and absence of adequate maintenance procedures, become an habitat where the microorganism can survive protect by biofilm. During the course of 3 years I had the opportunity to study and evaluate the different habitats correlated to Legionella growth and dissemination; in particular, I have studied the ability of Legionella to colonize these aquatic environments in which, as reported by the WHO, there are suitable conditions for their survival and multiplication, creating a risk to public health. The focus of my research is the hot water network of an hospital, and at the same time I could assess the presence of the microorganism in other conditions as the water lines circuit of the dental unit and a cooling towers, recently correlated to single case and epidemic events. The techniques used for detection and enumeration of Legionella are recognized and approved by the national and international scientific community: they are the traditional culture method (considered the gold standard) and molecular techniques (in particular PCR and sequencing multilocus), a main topic of my PhD activity. As suggested by Italian Guidelines for the Control and Prevention of Legionellosis published in May 2015, molecular techniques have been applied alongside the culture technique, according to the official or experimental protocols.