Legionella isolation was performed by cultural method, but different molecular techniques were implemented to identify Legionella strains in order to undertake the epidemiological investigation and establish the link with the source of infection. Our study was focused on a genotypic approach to evaluate Legionella contamination of a hospital hot water network (HWN) in association with the ISO11731-1998. The phylogenetic relationship between strains permitted to elaborate an environmental risk map. Materials/Methods: From October 2013 to July 2016, 547 hot water samples were analyzed to detect and enumerate Legionella in a HWN treated by a new disinfectant (WTP828) based on hydrogen peroxide (H2O2 ) + silver salts (Ag+ ). Isolates were serotyped using agglutination test and genotyped by mip gene sequencing and Sequence- Based Typing (SBT). Phylogenetic analysis was performed on the Phylogeny.fr platform and the tree was reconstructed by the maximum likelihood method. Results: Culture method permitted to identify 37% of positive samples belonging to L. pneumophila SG1 (60%) and L. species (40%). SBT assigned ST1 and ST104 to 123 samples of L. pneumophila. The mip gene sequencing identified inner L. species, L. anisa and L. rubrilucens in 82 positive samples. Phylogenetic analysis performed on strains of L. rubrilucens 1 / 2 inserimenti and L. anisa confirmed the presence of two separate clusters. The 100% of homology in 7 genes investigated in L. pneumophila strains did not permit to elaborate phylogenetic correlation. Conclusion: The genotypic approach used during environmental monitoring in a HWN under disinfection treatment might support the study of Legionella colonization. The elaboration of a phylogenetic map of isolates can help to correlatestrains in response to the disinfection treatment. These knowledges might support the HealthAuthority to rapidly undertake the epidemiological investigation and preventives measures.
Mancini B., I.M. (2017). Genotyping approach on environmental monitoring of Legionella spp. in a Hospital hot water network.
Genotyping approach on environmental monitoring of Legionella spp. in a Hospital hot water network
Cristino S.
Writing – Original Draft Preparation
2017
Abstract
Legionella isolation was performed by cultural method, but different molecular techniques were implemented to identify Legionella strains in order to undertake the epidemiological investigation and establish the link with the source of infection. Our study was focused on a genotypic approach to evaluate Legionella contamination of a hospital hot water network (HWN) in association with the ISO11731-1998. The phylogenetic relationship between strains permitted to elaborate an environmental risk map. Materials/Methods: From October 2013 to July 2016, 547 hot water samples were analyzed to detect and enumerate Legionella in a HWN treated by a new disinfectant (WTP828) based on hydrogen peroxide (H2O2 ) + silver salts (Ag+ ). Isolates were serotyped using agglutination test and genotyped by mip gene sequencing and Sequence- Based Typing (SBT). Phylogenetic analysis was performed on the Phylogeny.fr platform and the tree was reconstructed by the maximum likelihood method. Results: Culture method permitted to identify 37% of positive samples belonging to L. pneumophila SG1 (60%) and L. species (40%). SBT assigned ST1 and ST104 to 123 samples of L. pneumophila. The mip gene sequencing identified inner L. species, L. anisa and L. rubrilucens in 82 positive samples. Phylogenetic analysis performed on strains of L. rubrilucens 1 / 2 inserimenti and L. anisa confirmed the presence of two separate clusters. The 100% of homology in 7 genes investigated in L. pneumophila strains did not permit to elaborate phylogenetic correlation. Conclusion: The genotypic approach used during environmental monitoring in a HWN under disinfection treatment might support the study of Legionella colonization. The elaboration of a phylogenetic map of isolates can help to correlatestrains in response to the disinfection treatment. These knowledges might support the HealthAuthority to rapidly undertake the epidemiological investigation and preventives measures.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
