Yoko Takayama1, Hidehito Matsui2, Yuzuru Adachi3, Shin Nihonyanagi4, Tatsuhiko Wada5, Junko Mochizuki6, Nobuya Unno7, Hideaki Hanaki8. 1. 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. Electronic address: yoko@med.kitasato-u.ac.jp. 2. Infection Control Research Center, Kitasato Institute for Life Sciences, Kitasato University, 5-9-1 Shirokane, Minato-Ku, Tokyo, 108-8642, Japan. Electronic address: matsui-h@insti.kitasato-u.ac.jp. 3. Laboratory Department, Kitasato University Hospital, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0375, Japan. Electronic address: y.adachi@kitasato-u.ac.jp. 4. Department of Infection Control and Prevention, Kitasato University Hospital, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0375, Japan. Electronic address: shin0225@kitasato-u.ac.jp. 5. Department of Infection Control and Prevention, Kitasato University Hospital, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0375, Japan. Electronic address: wadatatu@med.kitasato-u.ac.jp. 6. Department of Obstetrics and Gynecology, Kitasato University School of Medicine, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0374, Japan. Electronic address: motizuki@med.kitasato-u.ac.jp. 7. Department of Obstetrics and Gynecology, Kitasato University School of Medicine, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0374, Japan. Electronic address: unno-tky@umin.ac.jp. 8. Infection Control Research Center, Kitasato Institute for Life Sciences, Kitasato University, 5-9-1 Shirokane, Minato-Ku, Tokyo, 108-8642, Japan. Electronic address: hanaki@insti.kitasato-u.ac.jp.
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.
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.
Authors: Ameneh Khatami; Tara M Randis; Anna Chamby; Thomas A Hooven; Margaret Gegick; Evan Suzman; Brady A'Hearn-Thomas; Andrew P Steenhoff; Adam J Ratner Journal: Open Forum Infect Dis Date: 2018-07-07 Impact factor: 3.835