山东省首例X群流行性脑脊髓膜炎病例流行病学调查和病原学鉴定

Epidemiological investigation and etiological identif ication of the f irst case of serogroup X meningococcal meningitis in Shandong province

目的对山东省1例X群流行性脑脊髓膜炎(流脑)病例进行流行病学调查和病原学鉴定。方法开展病例流行病学调查,采集病例血液和脑脊液标本及其密切接触者咽拭子标本进行脑膜炎奈瑟菌(Neisseria meningitides,Nm)分离培养和血清群鉴定,对菌株进行外膜蛋白porA、fetA基因分型和多位点序列分型以及抗生素敏感性试验。结果该病例为5岁男童,曾接种A群和A群C群脑膜炎球菌疫苗,无流脑病例接触史。病例及其密切接触者标本均检出X群Nm,属ST-7型和ST-5克隆群;菌株的porA基因VR1区为新基因型,VR2为9型,VR3为35-1型,fetA基因为F3-1型;菌株对环丙沙星、左氧氟沙星和复方新诺明耐药。结论该病例为山东省报告的首例X群流脑病例,菌株外膜蛋白porA基因发生变异且菌株耐药性强;提示X群流脑有流行风险,应加强流脑病原学监测。

Objective To determine the epidemiology and etiology of a serogroup X meningococcal meningitis case in Shandong province. Methods We implemented an epidemiological case investigation;collected blood and cerebrospinal fluid samples from the patient and throat swabs of his close contacts for isolation, culture, and Neisseria meningitidis(Nm) serogroup identification;determined genotypes of outer membrane protein porA and fetA of the isolated strain;and conducted multi-locus sequence typing and antibiotic sensitivity testing. Results The patient was a 5-year-old boy who had received group A and group A/C meningococcal vaccines and did not have a history of contact of anyone with meningococcal meningitis. A strain of serogroup X Nm was detected from the patient and his close contacts, and was identified as type ST-7 and ST-5 clonal complex. The VR1 region of the porA gene of the strain was a previously unknown genotype with the VR2 region being type 9 and the VR3 region being type 35-1. The fetA gene of the strain was type F3-1. The strain was resistant to ciprofloxacin, levofloxacin, and cotrimoxazole. Conclusion This serogroup X Nm case was first reported in Shandong;the strain had a porA gene mutation and strong drug resistance, indicating potential epidemic risk of serogroup X Nm and a need for strengthening pathogen surveillance..