Multilocus Sequence Typing Of Salmonella Isolates And Establishment And Evaluation Of MultiLocus Variable Numbers Tandem Repeats Analysis Of Salmonella Paratyphi A Isolates

The Serotype of Salmonlla is complex and the Multilocus Sequence Typing of Salmonella was performed to study the discriminability of MLST among different and same serotype of Salmonella isolates,and evaluate if the MLST is appropriate to predict the serotype of Salmonella or at least could afford valuable reference for the conformation of Salmonella serotype. We chose the 7 housekeeping genes MLST which was established by Attman of University College Cork and the housekeepings are aroC, dnaN, hemD, hisD, purE, sucA, thrA. This study involved 201 isolates of 2006-2007 in 5 regions that joined the Global Salmonella Surveillance(GSS) in China, and all the serotypes of isolates were identified for the second time and the PFGE was complemented when there were isolates that lacked PFGE results. In the end we got 46 STs(Sequence Types) and 45 serotypes in the study. The STs of Salmonella was in high accordance with the serotype and the combination of the two methods could afford more detailed background of samonella isolates for the epidemiological investigation and could be the complementarity of PFGE, In addition we foud that the human- and animal-associated Samonella isolates represented distinct and overlapping populations.The Samonella paratyphi A is common in the Southeast Asia and in China, when the PFGE was used to study Samonella paratyphi A the discrimination power was deficient, the Multiplocus Variable Numbers Tandem Repeats Analysis (MLVA) was used to study many pathogenic bacterias, so we tried to establish the of Salmonella paratyphi A and evaluate the value to application. The variable numbers tandem repeats (VNTRs) was affirmed in the genome of ATCC9150, and we utilized the polymorphic locations in the Salmonella paratyphi A isolates that different in region, time and PFGE bands as the panel to filter the VNTRs of MLVA, then we chose 97 Salmonella paratyphi A isolates of 1998-2008 in 9 regions in China to carry out MLVA and PFGE(SpeI) experiments and to compare their results to appraise the discriminability of MLVA ofSalmoneolla paratyphi A.We foud that the discriminatory power of MLVA is lower than PFGE(SpeI),but it still could reflect the epidemiological differences and relationship of S.paratyphi A, and when combined with PFGE the MLVA could supply more discriminatory power,so it could be used as a supplement of PFGE.