Rizek Camila F, Luiz André Machado, Assis Gracilene Ramos de, Costa Silvia Figueiredo, Levin Anna Sara, Lopes Marta Heloisa
University of São Paulo, School of Medicine, Department of Infectious Diseases, Laboratory of Bacteriology (LIM-54). São Paulo, SP, Brazil. E-mails:
University of São Paulo, School of Medicine, Department of Infectious Diseases, São Paulo, SP, Brazil. E-mails:
Rev Inst Med Trop Sao Paulo. 2016 Sep 22;58:60. doi: 10.1590/S1678-9946201658060.
Neisseria meningitidis is a cause of several life-threatening diseases and can be a normal commensal in the upper respiratory tract of healthy carriers. The carrier rate is not well established especially because there is no standard method for the isolation of N. meningitidis. Therefore, the aim of this study was to compare identification methods for the carrier state. Two swabs were collected from 190 volunteers: one was cultured and the other had DNA extracted directly from the sample. The Polymerase Chain Reaction (PCR) was performed to determine species and serogroups and compared the results between the methods. PCR for species determination used two pairs of primers and when there was only one amplicon, it was sequenced. The culture technique was positive in 23 (12.1%) subjects while the direct extraction method was positive in 132 (69.5%), p < 0.001. Among the 135 subjects with positive N. meningitides tests, 88 (65.2%) were serogroup C; 3 (2.2%) serogroup B; 5 (3.7%) were positive for both serogroup B and C, and 39 (28.9%) did not belong to any of the tested serogroups. In this study, PCR from DNA extracted directly from swabs identified more N. meningitidis asymptomatic carriers than the culture technique.
脑膜炎奈瑟菌是多种危及生命疾病的病因，在健康携带者的上呼吸道中也可能是正常共生菌。携带者率尚未明确，尤其是因为目前尚无分离脑膜炎奈瑟菌的标准方法。因此，本研究的目的是比较携带者状态的鉴定方法。从190名志愿者中采集了两支拭子：一支用于培养，另一支直接从样本中提取DNA。进行聚合酶链反应（PCR）以确定菌种和血清群，并比较两种方法的结果。用于菌种鉴定的PCR使用了两对引物，当只有一个扩增子时，对其进行测序。培养技术在23名（12.1%）受试者中呈阳性，而直接提取法在132名（69.5%）受试者中呈阳性，p<0.001。在135名脑膜炎奈瑟菌检测呈阳性的受试者中，88名（65.2%）为C血清群；3名（2.2%）为B血清群；5名（3.7%）B和C血清群均呈阳性，39名（28.9%）不属于任何检测的血清群。在本研究中，直接从拭子中提取DNA进行PCR检测出的无症状脑膜炎奈瑟菌携带者比培养技术更多。
