Identification of a newly reported Francisella species by average nucleotide identity based on high-throughput whole genome sequencing technology / 临床检验杂志

ABSTRACT

Objectives To identify the Francisella strain isolated from blood of a patient with drowning-associated pneumonia.Methods The whole genome of the strain,designated Wenzhou1,was sequenced using the high throughput sequencing technology by 2000/miSeq system of Illumina platform,and the obtained genome draft was assembled by MicrobeTrakr Plus software.The phylogenetic neighbors of Wenzhou1 were obtained by NCBI BLAST analysis from GenBank database for the gene sequences of 16S rRNA,malate dehydrogenase(mdh),DNA-directed RNA polymerase subunit beta (rpoB) and succinate dehydrogenase subunit alpha (sdhA).The average nucleotide identity(ANI) between Wenzhou1 and its phylogenetic neighbors was analyzed by the software OrthoANI using NCBI BLAST search under the Java Runtime Environment Version 8.Results The genome size of Wenzhou1 was 1.96 × 106 bp,containing 74 contigs.The genomic G + C mol％ of Wenzhou1 was 32.1％,which was similar to the other species of genus Francisella and Allofranicella.Based on the analysis of NCBI BLAST of GenBank for the similarities of 16S rRNA gene,mdh gene,rpoB gene and sdbA gene sequences,Wenzhou1 was most closely related to F.hispaniensis FSC454 and Francisella cf.novicida 3523.The ANI of Wenzhou1 was 97.8％ to F.hispaniensis FSC454,97.5％ to 97.6％ to Francisella cf.novicida 3523,but only 91.3％ to 91.5％ to the four subspecies of F.tularensis.Conclusion ANI analysis based on whole genome sequence should be an accurate,effective method for bacterial identification.Wenzhou1 could be identified as F.hispaniensis by ANI with high-throughput whole genome sequencing technology.