安徽省阜阳市首例W群流行性脑脊髓膜炎死亡病例病原学分析

Etiological analysis on the first death of meningococcal meningitis caused by Neisseria meningitidis serogroup W in Fuyang, Anhui

  • 摘要:
      目的  对安徽省阜阳市2020年1月某寄宿学校1例疑似流行性脑脊髓膜炎(流脑)死亡病例开展流行病学调查与病原学分析,了解其传播途径和传染源,为及时有效阻止疫情扩散提供科学依据。
      方法  依据WS 295—2019《流行性脑脊髓膜炎诊断》,采集病例血液和密切接触者咽拭子,现场接种,及时保温运送至实验室进行分离培养,同时用聚合酶链式反应方法开展种特异性鉴定,对分离出的菌株进行分群鉴定、采用K-B纸片扩散法和E-test试纸条法进行药敏试验,用脉冲场凝胶电泳(PFGE)技术分析其同源性。
      结果  从病例血液和密切接触者咽拭子中共分离出13株脑膜炎奈瑟菌,均为W群,密切接触者菌株携带率为66.67%(12/18),PFGE分型显示病例和密切接触者菌株高度相似,相似度为92.60%~100.00%。 所有菌株对头孢曲松、头孢噻肟、氯霉素、利福平、美罗培南、阿奇霉素、米诺环素敏感,对青霉素、氨苄西林中介,对环丙沙星、复方新诺明、左氧氟沙星耐药。
      结论  密切接触者和病例均检出W群脑膜炎奈瑟菌,流行病学调查发现,本病例为阜阳市首例W群流脑病例。 密切接触者病原菌携带率较高,W群流脑存在流行趋势,应加强对其监测,及时采取干预措施,同时应注意抗菌药物的合理使用。

     

    Abstract:
      Objective  To understand the etiological characteristics of a death of suspected meningococcal meningitis in a boarding school in Fuyang, Anhui province, in January 2020, identify its transmission route and source of infection, and provide scientific evidence for the timely and effective control of the spread of the epidemic.
      Methods  On the basis of the diagnosis criteria for meningococcal meningitis (WS 295—2019), blood samples of the cases and throat swabs of close contacts were collected, and field inoculation, heat preservation and timely transfer of the samples were conducted for pathogen culture in laboratory, at the same time polymerase chain reaction (PCR) was used for specific identification of serogroup. K-B disk diffusion method and E-test strip method were used for antimicrobial susceptibility test. The homology of the strains was analyzed by pulsed field gel electrophoresis (PFGE).
      Results  A total of 13 strains of Neisseria meningitidis were isolated from the blood samples of cases and throat swabs of close contacts. All the strains belonged to serogroup W. The carriage rate of N. meningitidis W in close contacts was 66.67% (12/18). PFGE showed that the patterns of the strains isolated from the cases and close contacts were highly similar, and the similarity was 92.59%−100.00%. All the strains were sensitive to ceftriaxone, cefotaxime, chloramphenicol, rifampicin, meropenem, azithromycin, minocycline, intermediate to penicillin and ampicillin, and resistant to ciprofloxacin, compound sulfamethoxazole and levofloxacin.
      Conclusion  N. meningitidis W was detected in both the cases and the close contacts. Epidemiological investigation revealed that the death was the first case caused by infection of N. meningitidis W in Fuyang. The pathogen carriage rate in close contacts was high, suggesting the risk of epidemic caused by N. meningitidis W. It is necessary to strengthen the surveillance for N. meningitidis W, take timely intervention measures, and pay attention to the rational use of antibiotics.

     

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