Population genetic analysis o Salmonella entrica serovar Enteritidis isolates collected rom Iranian commercial poultry abattoirs between 2009 and 2011 based on VNTR(MLVA)

Salmonella enterica is recognized as one o the major ood-borne pathogens with more than 2,600 serotypes worldwide. It is a zoonotic disease which can be ound in many sources including animals and environment. Ingesting raw or undercooked ood or cooked ood not kept in proper condition or cross contaminated, would lead to human inection. rom the public health point o view, in case o diagnosis o inection with Salmonella origin, it is required to notiy the national health authorities or territory health departments by the laboratory. Sub-typing o isolates via genotyping is necessary to enhance epidemiological data or the detection o outbreaks and identiication o the inection source. DNA-based strain-typing methods or bacterial pathogens play an important role in tracing inectious-disease transmissions, and have been used widely to identiy Salmonella clinical isolates rom animals' ood-borne disease. Moreover successul molecular typing method could be o great help in precise characterization o strains used or production o vaccines. Salmonella enterica Enteritidis is the most requent etiological agent o salmonellosis in humans and poultry. To analyze the population genomic structure o Salmonella enterica Enteritidis in Iran as the main aim o this study, we examined 81 chicken isolates comprised o 18 broiler arms and ew non-epidemic human isolates rom six geographically distant provinces by multi-locus ٧٧ variable-number tandem repeat analysis (MLVA). Among SE2, SE3, SE5, SE7, SE8, SENTR4, and SENTR7, only SE5 with our and SENTR7 with two alleles, respectively, proved variable giving estimates o locus genetic diversity o 0.58 and 0.15. In all, six closely related MLVA proiles were identiied among which three were commonly represented by human and chicken isolates.This population homogeneity contrasts with the high diversity at these loci reported elsewhere and is likely a consequence o a single clone o S. Enteritidis distributed across Iran, which would be an eective inding regarding the uture prophylactic policies around the country Using polymerase chain reaction, all these selected DNA ragments were ampliied and gone under observatory evaluations by Agarose gel electrophoresis and conirmed by DNA sequencing procedures in both directions, using Nie's index or each locus and Simpson's index or all sevenlocus system, their diversity index was measured. Based on our results ive out o seven VNTR loci showed no diversity and the remainder two including SE5 and SENTR7 showed 0.58 and 0.15 Nei's diversity index respectively. In VNTR, six closely related MLVA proiles were identiied which showed a level o 0.66 Simpson's diversity index. urther to our study's scope based on MLST (Multi Locus Sequence Typing) scheme no diversity was detected among our population which later was veriied through positive and negative controls. As a subsidiary technical inding along with mentioned results, this study succeeded to present " An optimized aordable DNA-extraction method rom Salmonella enterica Enteritidis or PCR experiments " to acilitate our main objectives and research goals achievements. As results showed, treatment o crude cell extracts rom S. Enteritidis with proteinase K oers an inexpensive, ast and eective DNA extraction method suitable or high-throughput laboratories. In conclusion given the act that no Salmonella vaccination strategy has been implemented in Iran, successul identiication o the current circulating Salmonella serotypes gone under precise VNTR and MLST genotyping investigations, which would relect genuine population structure o this microorganism throughout the country, provides a glorious horizon toward representing a novel national poly-valent vaccine.