宁波地区志贺菌血清分型、耐药性和毒力分析

Serotyping, drug resistance and virulence analysis of Shigella in Ningbo area

目的 了解志贺菌血清型动态、耐药性和毒力情况,为防控和治疗提供依据。方法 志贺菌检测和鉴定采用国家标准方法,药敏试验采用改良K-B法,耐药和毒力基因采用PCR法。结果 254株志贺菌分B、D和C共3个血清群,分别为170株、83株和1株,占66.93%、32.68%和0.39%。B群又分为10个亚型,其中福氏c亚型(1c、2c和4c)最多,占54.12%(92/170)。ipaH、set1A、set1B、sen、ial和virA毒力基因中,菌株检出率分别为100.00%、88.04%、88.04%、80.43%、93.48%和88.04%,菌株携带毒力基因最多5种,最少2种。药敏检测显示2株B群志贺菌对检测抗生素全部敏感,其余菌株耐药在4种~13种,未检出耐碳青霉烯类抗生素的志贺菌。结论 随着福氏c亚型志贺菌传入本市,其流行株血清型发生了变迁,Fc亚型志贺菌成为新的流行株,且ESBLs株最高,携带毒力基因最多,使其更容易逃避宿主的免疫杀伤,增加临床抗生素治疗难度。

Objective This paper aims to understand the serotype dynamics change, drug resistance and virulence of Shigella and provide basis for the prevention, control and treatment of the disease caused by Shigella. Methods The detection and identification of Shigella were conducted using the national standard method. The drug sensitivity test was done according to the modified K-B method, and the drug resistance genes and the virulence genes were determined by PCR method. Results A total of 254 Shigella strains were divided into serogroup B(170 strains), serogroup D(83 strains) and serogroup C(1 strain), respectively accounting for 66.93%, 32.68% and 0.39%. Group B was subdivided into 10 subtypes, among which Shigella flexneri c subtypes(1c, 2c and 4c) occupied the dominance, accounting for 54.12%(92/170). Among the virulence genes of ipaH, set1A, set1B, sen, ial, and virA, the detection rates of the strains were 100.00%, 88.04%, 88.04%, 80.43%, 93.48% and 88.04%. The most 5 virulence genes and the least 2 virulence genes were carried among the strains. Drug susceptibility testing showed that the two Shigella group B strains were both sensitive to antibiotics, and the remaining strains were resistant from 4 to 13 species, and the Shigella strain resistant to carbapenem antibiotics was not detected. Conclusion With the epidemic of Shigella flexneri subtype c in Ningbo City, the serotype of its epidemic strains has changed. Fc subtype of Shigella has become a new epidemic strain, and the number of ESBLs strains is the highest and they carry the most virulence genes. It is prone to escape the host’s immune capture, which increases the difficulty of clinical antibiotic treatment.