Detection of Streptococcus agalactiae by immunochromatography with group B streptococcus-specific surface immunogenic protein in pregnant women. Issue 10 (October 2017)

• Record Type: Journal Article
• Authors: Takayama, Yoko; Matsui, Hidehito; Adachi, Yuzuru; Nihonyanagi, Shin; Wada, Tatsuhiko; Mochizuki, Junko; Unno, Nobuya; Hanaki, Hideaki
• Is Part Of: Journal of infection and chemotherapy. Volume 23:Issue 10(2017:Oct.)
• Page Start: 678
• Page End: 682
• Publication Date: 2017-10
• Subjects: Streptococcus agalactiae -- GBS-specific Sip antigen -- Immunochromatography -- Rapid detection -- Small institutions; Chemotherapy -- Periodicals; Infection -- Periodicals; Communicable diseases -- Chemotherapy -- Periodicals; 615.5805
• DOI: 10.1016/j.jiac.2017.07.001
• Languages: English
• ISSNs: 1341-321X

Abstract

Abstract: Background: 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. Materials and methods: 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. Results: 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. Conclusions: 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.