Evaluation of pulsed-field gel electrophoresis for Legionella subtyping

Objective To evaluate the capability of pulsed-field gel electrophoresis (PFGE) for the subtyping of Legionella. Methods A total of 117 Legionella reference strains and environmental strains were analyzed by PFGE with Asc Ⅰ. Combined with the number and distributions of bands in the PFGE patterns, capability of subtyping, distinguishability of patterns and epidemiological information, we evaluated the capability of Asc Ⅰ-PFGE for Legionella subtyping. Results All Legionella pneumophila serotypes strains and 17 non-L. pneumophila strains showed high qualitative PFGE patterns; however, for other 13 non-L. pneumophila serotypes strains, most of the PFGE bands were distributed with small weight. Asc Ⅰ-PFGE could cluster the isolates from each water system into the same or very similar patterns and distinguish the strains with different sources. By Asc Ⅰ-PFGE, L. pneumophila subtyping had a high degree of consistency with epidemiological data of strains. Conclusion Asc Ⅰ-PFGE could be used in the subtyping of L. pneumophila and 17 non-L. pneumophila strains, and be applied in the epidemiological investigation of L. pneumophila disease.