Establishment and application of PFGE database on <I>Salmonella enterica</I> serotype Paratyphi A in Yuxi, Yunnan

ObjectiveTo establish the PFGE database on Salmonella enterica serotype Paratyphi A (SPA) in Yuxi and to identify the distribution of SPA of varying subtypes in Yuxi, providing scientific basis for surveillance and emergency response of SPA in the city. MethodsThe chromosomes of 194 SPA strains isolated from seven counties in Yuxi were digested with restriction endonuclease Xba I and Spe I. PFGE typing and cluster analysis was employed to determine the distribution of SPA. ResultsThere were seven XbaI subtypes out of 194 SPA strains, including Xba I01, Xba I02, Xba I06, Xba I07, Xba I09, Xba I10 and Xba I19, of which Xba I01 predominated with the proportion of 93.81％(182/194). There were ten Spe I subtypes (Spe I01-10) out of 194 strains, Spe I01 and Spe I02 being prevalent with the proportion of 46.39%（90/194） and 43.30%（84/194）, respectively. Comparison between Xba I and Spe I band patterns suggested greater amount of band patterns of Xba I digestion than that of Spe I digestion, which was due to more Spe I patterns derived from Xba I01 and Xba I02 in contrast with Spe I01 and Spe I02 patterns originated solely from Xba I01. However, different Xba I patterns were found to generate the same Spe I band. ConclusionThe PFGE database featuring highly-consistent SpeI and Xba I digestion datasets was established. Although SpeI01 and SpeI02 (or XbaI01) constituted the major prevalent clones, other detrmental subtypes must not be ignored in Yuxi.