Application of OrthoANI combined with MALDI-TOF MS in identification and typing of Campylobacter fetus / 中华检验医学杂志

ABSTRACT

Objective@#Establishing the mass spectrum library of a new Campylobacter- " C.fetus subsp.testudinum" for rapid species identification in clinical microbiology laboratory.@*Methods@#Illumina second generation sequencing platform 2000/miSeq was used to carry out high flux genome sequencing for the strains which were collected to establish mass spectrum library.The analysis oforthologous average nucleotide identity (OrthoANI) between collected strains and reference strains was performed at JAVA 8 operation environment. Then, the mass spectrums ofcollected strains andreference strains were acquired using MALDI-TOF MS. And the mass spectrum library of C. fetus subsp.testudinum. were established and verified.@*Results@#The OrthoANI analysis showed that the OrthoANI value of the collected strains and the reference strain C. fetus subsp.testudinum03-427 was 99.30%-99.96%, while the OrthoANI values of collected strains and C. fetus subsp.venerealisNCTC10354 orC.fetus subsp.fetus82-40 were 91.05%-92.26%. With reference to OrthoANI ≥ 95% as the basis for the determination of the same strain, the strains which collected to establish mass spectrum library was finally identified as " C. fetus subsp.testudinum" . The identification accuracy rate of the mass spectrum library was 100% (consistent with gene sequencing), and the confidence interval was 82.3%-99.9%, identification of the same strain is 100% reproducible.@*Conclusions@#The new" gold standard" based on high throughput sequencing and total genome analysis has provided the ideal reference value for the establishment of mass spectrum library.And the accurate and objective reference spectrum of the" C.fetus subsp.testudinum" provides a new platform for the rapid diagnosis of fetal Campylobacter infection. (Chin J Lab Med, 2018, 41 583-588)