A comparative Study on differential identification of Citrobacter freundii complex between molecular biological identification method and matrix assisted laser desorption ionization-time-of-flight mass spectrometry
10.11816/cn.ni.2025-241715
- VernacularTitle:弗劳地柠檬酸杆菌复合群分子生物学和基质辅助激光解析电离飞行时间质谱鉴定方法比较
- Author:
Huanhuan YAN
1
;
Guangcun ZHANG
;
Qiang ZHAO
;
Kun YE
;
Jiyong YANG
;
Liyan YE
Author Information
1. 中国人民解放军医学院,北京 100039;中国人民解放军总医院第一医学中心检验科,北京 100853
- Publication Type:Journal Article
- Keywords:
Citrobacter freundii complex;
Molecular biological identification;
Average nucleotide identity;
Phyloge-netic analysis;
Matrix assisted laser desorption ionization-time-of-flight mass spectrometry
- From:
Chinese Journal of Nosocomiology
2025;35(9):1281-1286
- CountryChina
- Language:Chinese
-
Abstract:
OBJECTIVE To evaluate the performance of commonly used molecular biological identification methods in differential identification of Citrobacter freundii complex(Cfc)and find out the differences in the mass spectra among the prevalent species of Cfc so as to facilitate the rapid and accurate identification.METHODS Totally 150 clinical strains were isolated from The First Medical Center of Chinese PLA General Hospital from 2015 to 2020 and were identified as Cfc by means of matrix assisted laser desorption ionization-time-of-flight mass spectrometry(MALDI-TOF MS),the genome data were obtained by the next generation sequencing and were compared with reference genome of Citrobacter species from National Center of Biotechnology Information(NCBI)based on aver-age nucleotide identity(ANI),phylogenetic analyses of rec N gene,concatenated alignments of four housekeeping genes(fusA,pyrG,leuS and rpoB as well as gyrB,rplB,fusA and leuS),core genome single nucleotide poly-morphism(coreSNP)and whole genome(WG),digital DNA-DNA hybridization(dDDH)analysis,ribosomal multilocus sequence typing(rMLST)and typical(strain)genome service(TYGS)analysis.ANI was set as the'gold standard' for the identification of the Cfc strains,and the capabilities of the various methods were evaluated.A certain number of strains of Citrobacter freundii(Cfr),Citrobacter braakii(Cbr)and Citrobacter portucalen-sis(Cpo)were randomly selected to obtain and compare the mass spectra so as to find out the differences in the mass spectra.RESULTS The identification capability of the Cfc strains is limited based on the available database for MALDI-TOF MS,Cpo was prone to be misidentified as Cfr or Cbr.The mass spectrum between Cpo and Cfr ranged between 2600 and 2660 m/z,the mass spectrum between Cpo and Cbr ranged between 5200 and 5300 m/z,showing significant difference.The concatenated alignments of four housekeeping genes gyrB,rplB,fusA and leuS,CoreSNP and WG phylogenetic analysis had high accurate rate of identification.CONCLUSIONS The meth-ods have certain limitations in identification of Cfc.The joint application of ANI with the methods such as WG phylogenetic analysis,update of mass spectrum database and timely establishment of database can achieve the ac-curate identification of the species of Cfc.
