Analysis of serotype distribution and genomic characteristics of dominant strains of streptococcus pneumoniae
Objective To understand the serotype distribution and genomic characteristics of dominant strains of streptococcus pneumoniae,and provide technical support for prevention and control of infectious diseases caused by Sp.Methods The Sp strains isolated from clinical pneumonia cases were collected in sentinel hospitals from 2021 to 2023.The drug sensitivity test,multiple PCR serotyping,PFGE molecular typing and whole genome sequencing were carried out after re-identification.The multi-site sequence typing(MLST),core genome multi-site sequence typing(cgMLST),drug resistance genes and virulence genes were obtained.The phylogenetic tree was constructed by FastTree as the genome-wide single nucleotide polymorphism(wgSNP)sequence.Results Totally 76 Sp strains were sensitive to moxifloxacin,linezolid,vancomycin,levofloxacin,teicoranin,chloramphenicol and cefepime,but resistant to erythromycin,tetracycline and clindamycin,with resistance rates of 98.68％,93.42％and 90.79％.There were 17 drug resistant spectrum,of which,cefotaxime-erythromycin-tetracycline-penicillin-sulfamethoxazole-clindamycin was the dominant drug resistant spectrum type,accounting for 34.21％.There were 12 serotypes after multiplex PCR,and the top 3 serotypes were 19F(48.68％),6B(14.47％),14(5.26％),and the 19F was the dominant serotype.The type of PFGE band of 64 Sp strains showed overall diversity.There were 35 strains of 19F type showed 15 PFGE band types,and the spn004 was the dominant PFGE band type with homology.The analysis of genome-wide of 27 strains of Sp showed that there were 5 MLST and 12 cgMLST.The dominant type was ST271,accounting for 81.50％in MLST types,and was cgST3308,accounting for 33.34％in cgMLST types.There were 14 drug resistance genes and 35 virulence genes detected in 27 strains of Sp.The genome-wide SNP phylogenetic analysis showed that there were three evolutionary branches,C1 branch was the dominant branch,with the closest genetic distance and the relatively long from C2 and C3.Conclusions From 2021 to 2023,the dominant serotype of Sp was 19F in sentinel hospitals,with genetic relationship among the dominant branch strains.The situation of drug resistance is serious.
万方数据
维普
