Molecular typing and distribution characteristics of Legionella pneumophila isolated from cooling water of central air conditioning system in Zhongshan, 2012-2018 / 公共卫生与预防医学

ABSTRACT

Objective To analyze the genetic characteristics of Legionella pneumophila isolated from cooling water of central air conditioning system in public places in Zhongshan from 2012 to 2018, and to understand the spatiotemporal distribution of homologous strains, in order to provide evidence for the prevention, control and traceability of Legionella pneumophila infection. Methods Eighty-five Legionella pneumophila strains were isolated for serotype identification, and the molecular typing of the 85 isolates was performed using pulsed field gel electrophoresis (PFGE). The strain location data was converted into latitude and longitude coordinates by GIS geocoding technology. The converted location data was overlaid on the map of Zhongshan City, mapping the molecular typing distribution of clusters using Qgis2.18.11 spatial processing software. Results Eighty-five strains of Legionella pneumophila included 9 serotypes, and the highest proportion was LP1, accounting for 61.18% (52/85). According to the similarity of 100%, 85 strains of Legionella pneumophila were divided into 56 patterns of PFGE bands (T1-T56), with 3 types being dominant. Same serotype of Legionella pneumophila strains showed diverse PFGE patterns. Different serotypes of Legionella pneumophila strains were basically identified as different PFGE patterns, while some were identified as same PFGE pattern. According to over 85% similarity, 8 clusters (A-H) were designated, strains of which were distributed in 12 districts. PFGE clustering clusters did not display obvious temporal and regional distribution differences, nor did they have temporal and regional clustering distributions. Conclusion Strains of Legionella pneumophila isolated from cooling water of central air conditioning system in public places in Zhongshan from 2012 to 2018 showed genetic diversity, and the main serotype was LP1. Isolates of clusters did not exist in different years or regions.