Takayama Yoko, Matsui Hidehito, Adachi Yuzuru, Nihonyanagi Shin, Wada Tatsuhiko, Mochizuki Junko, Unno Nobuya, Hanaki Hideaki
Department of Infection Control and Infectious Diseases, Research and Development Center for New Medical Frontiers, Kitasato University School of Medicine, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0374, Japan; Department of Infection Control and Prevention, Kitasato University Hospital, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0375, Japan.
Infection Control Research Center, Kitasato Institute for Life Sciences, Kitasato University, 5-9-1 Shirokane, Minato-Ku, Tokyo, 108-8642, Japan.
J Infect Chemother. 2017 Oct;23(10):678-682. doi: 10.1016/j.jiac.2017.07.001. Epub 2017 Aug 2.
Infection with Streptococcus agalactiae (Group B streptococcus: GBS) is a significant cause of morbidity and mortality in neonates. Screening for GBS is mainly done by culture-based methods, but a reliable result may take several days to obtain and culture is difficult to perform at institutions without a laboratory. We evaluated an immunochromatography method for rapid detection of GBS-specific surface immunogenic protein (Sip) using anti-Sip monoclonal antibodies.
A total of 377 cervical and vaginal swabs collected during weeks 35-37 of gestation were inoculated into GBS medium F and incubated. Growth of microorganisms and production of red/orange pigment were assessed by observation. Then culture extracts were subjected to immunochromatography and were also inoculated onto chromID Strepto B (STRB) medium, after which isolates were serotyped and characterized by PCR.
Of the 377 samples, 54 (14.3%) were positive for GBS by immunochromatography after incubation in GBS medium F. On the other hand, GBS was isolated from 58 (15.4%) of the 377 samples by culture with GBS medium F and STRB medium. Ten of the 58 isolates were non-pigmented and 4 of these were not detected by immunochromatography. The sensitivity, specificity, positive predictive value, and negative predictive value of immunochromatography were 93.1% (54/58), 100% (319/319), 100% (54/54), and 98.8% (319/323), respectively.
Immunochromatography was comparable to culture on STRB medium for detecting GBS, indicating that this method could be used clinically for GBS screening in pregnant women even at small institutions.
无乳链球菌（B组链球菌：GBS）感染是新生儿发病和死亡的重要原因。GBS筛查主要通过基于培养的方法进行，但可靠结果可能需要数天才能获得，并且在没有实验室的机构中难以进行培养。我们评估了一种使用抗Sip单克隆抗体快速检测GBS特异性表面免疫原性蛋白（Sip）的免疫层析方法。
将妊娠35 - 37周期间收集的377份宫颈和阴道拭子接种到GBS培养基F中并进行培养。通过观察评估微生物的生长和红色/橙色色素的产生。然后将培养提取物进行免疫层析，并且也接种到chromID B族链球菌（STRB）培养基上，之后对分离株进行血清分型并通过PCR进行鉴定。
在GBS培养基F中培养后，377份样本中有54份（14.3%）通过免疫层析检测GBS呈阳性。另一方面，通过GBS培养基F和STRB培养基培养，从377份样本中的58份（15.4%）分离出GBS。58株分离株中有10株无色素，其中4株未通过免疫层析检测到。免疫层析的敏感性、特异性、阳性预测值和阴性预测值分别为93.1%（54/58）、100%（319/319）、100%（54/54）和98.8%（319/323）。
免疫层析在检测GBS方面与STRB培养基培养相当，表明该方法即使在小型机构中也可临床用于孕妇GBS筛查。
