儿科病房无乳链球菌感染的临床特点和病原菌基因多态性

The genotype of pathogen and clinical symptoms of Streptococcus agalactiae infection in newborns and infants

目的研究儿科病房无乳链球菌感染的临床表现,并对分离的无乳链球菌进行基因多态性分析。方法收集台州市中心医院新生儿室和儿科病房2017年1月至2017年12月无乳链球菌侵袭性感染病例,分析临床表现特点。采用多位点序列分型技术,对分离的无乳链球菌7个管家基因进行PCR扩增及测序,并与BLAST数据库中的序列进行比对分析,明确菌株序列性(ST)。结果本次研究共纳入7例患儿,分离到7株无乳链球菌。7株无乳链球菌基因型中2株病原菌基因型为ST12,2株ST249,1株ST23,1株ST1076及未知型1株。小儿无乳链球菌感染临床表现为败血症的有4例,其中2例病原菌基因型为ST12,2例为ST249。临床表现为脑膜炎的1例,基因型为ST249。结论该院小儿无乳链球菌感染的基因型以ST12和ST249为主;临床表现以败血症和化脓性脑膜炎为主,预后不佳。

Objective To study the clinical symptoms of Streptococcus agalactiae infection and the genotype of the pathogen. Methods Newborn and infant infected with Streptococcus agalactiae in our hospital from Jan 2017 to Apr 2018 were recruited as the subjects. Multilocus sequence typing technique was used to identify the sequences of 7 house keeping genes. The results were analyzed and compared with the sequence information in BLAST database to confirm the sequence types(ST) of the strains. Results 7 strains of Streptococcus agalactiae were isolated, including two strains of ST12 type, two strains of ST249 type, one strain of ST23, one strain of ST1076, and one strain of NT type. There were 4 cases with clinical manifestation of sepsis, in which ST12 accounted for 28.2%(2/7 cases). There was 1 case with clinical manifestation of purulent meningitis, accounting for 14.2%(1/7 cases). Conclusion The major genotypes of pathogens in newborns and infants infected by Streptococcus agalactiae are ST12 and ST249. The clinical manifestations are mainly sepsis and purulent meningitis, with a poor prognosis.