title: Development of a colloidal gold immunochromatographic strip for rapid detection of Streptococcus agalactiae in tilapia.
abstract: A colloidal gold immunochromatographic strip was developed for rapid detection of Streptococcus agalactiae (S. agalactiae) infection in tilapia. The monoclonal antibodies (mAb) 4C12 and 3A9 were used to target S. agalactiae as colloidal gold-mAb conjugate and captured antibody, respectively. The colloidal gold immunochromatographic strip was assembled via routine procedures. Optimal pH and minimum antibody levels in the reaction system for gold colloidal-mAb 4C12 conjugation were pH 7.4 and 18μg/mL, respectively. Optimal concentrations of the captured antibody 3A9 and goat anti-mouse antibody were 0.6mg/mL and 2mg/mL, respectively. The sensitivity of the strip for detecting S. agalactiae was 1.5×105colony forming units (CFU). No cross-reaction was observed with other commonly encountered bacteria, including Pseudomonas fluorescens, Aeromonas hydrophila, Vibrio anguillarum and Streptococcus iniae. The assay time for S. agalactiae was less than 15min. Tilapia samples artificially infected with S. agalactiae were tested using the newly developed strip. The results indicated that blood, brain, kidney, spleen, metanephros and intestine specimens of infected fish can be used for S. agalactiae detection. The validity of the strip was maintained for 6 months at 4°C. These findings suggested that the immunochromatographic strip was effective for spot and rapid detection of S. agalactiae infected tilapia.
authors.affiliation: Animal Science and Technology College, Guangxi University, 100 Daxue Road, Xixiangtang District, Nanning, Guangxi 530005, China.
authors.forename: Wu
authors.initials: W
authors.lastname: Wen-de
authors.affiliation: Guangxi Key Laboratory of Aqua tic Genetic Breeding and Healthy Aquaculture，Guangxi Academy of Fishery Science, 8 Qingshan Road, Nanning, Guangxi 530021 China.
authors.forename: Li
authors.initials: L
authors.lastname: Min
authors.affiliation: Guangxi Key Laboratory of Aqua tic Genetic Breeding and Healthy Aquaculture，Guangxi Academy of Fishery Science, 8 Qingshan Road, Nanning, Guangxi 530021 China.
authors.forename: Chen
authors.initials: C
authors.lastname: Ming
authors.affiliation: Guangxi Key Laboratory of Aqua tic Genetic Breeding and Healthy Aquaculture，Guangxi Academy of Fishery Science, 8 Qingshan Road, Nanning, Guangxi 530021 China.
authors.forename: Li
authors.initials: L
authors.lastname: Li-Ping
authors.affiliation: Guangxi Key Laboratory of Aqua tic Genetic Breeding and Healthy Aquaculture，Guangxi Academy of Fishery Science, 8 Qingshan Road, Nanning, Guangxi 530021 China.
authors.forename: Wang
authors.initials: W
authors.lastname: Rui
authors.affiliation: Animal Science and Technology College, Guangxi University, 100 Daxue Road, Xixiangtang District, Nanning, Guangxi 530005, China.
authors.forename: Chen
authors.initials: C
authors.lastname: Hai-Lan
authors.affiliation: Guangxi Key Laboratory of Aqua tic Genetic Breeding and Healthy Aquaculture，Guangxi Academy of Fishery Science, 8 Qingshan Road, Nanning, Guangxi 530021 China.
authors.forename: Chen
authors.initials: C
authors.lastname: Fu-Yan
authors.affiliation: Guangxi Aquaculture and Animal Husbandry School, 7 Qingshan Road, Nanning, Guangxi 530021, China.
authors.forename: Mi
authors.initials: M
authors.lastname: Qiang
authors.affiliation: Guangxi Key Laboratory of Aqua tic Genetic Breeding and Healthy Aquaculture，Guangxi Academy of Fishery Science, 8 Qingshan Road, Nanning, Guangxi 530021 China. Electronic address: nnlww@126.com.
authors.forename: Liang
authors.initials: L
authors.lastname: Wan-Wen
authors.affiliation: Animal Science and Technology College, Guangxi University, 100 Daxue Road, Xixiangtang District, Nanning, Guangxi 530005, China. Electronic address: chenhanz211@163.com.
authors.forename: Chen
authors.initials: C
authors.lastname: Han-Zhong
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000737:chemistry; D000911:Antibodies, Monoclonal / Q000737:chemistry; D015374:Biosensing Techniques / Q000295:instrumentation; D002846:Chromatography, Affinity / Q000295:instrumentation*; D004867:Equipment Design; D005260:Female; D005393:Fish Diseases / Q000175:diagnosis* / Q000382:microbiology*; D017979:Gold Colloid / Q000737:chemistry; D018796:Immunoconjugates / Q000737:chemistry; D051379:Mice; D008807:Mice, Inbred BALB C; D011934:Reagent Strips / Q000032:analysis*; D012680:Sensitivity and Specificity; D013290:Streptococcal Infections / Q000175:diagnosis / Q000382:microbiology / Q000662:veterinary*; D013292:Streptococcus agalactiae / Q000302:isolation & purification*; D017210:Tilapia / Q000382:microbiology*
chemical_list: D000907:Antibodies, Bacterial; D000911:Antibodies, Monoclonal; D017979:Gold Colloid; D018796:Immunoconjugates; D011934:Reagent Strips
keywords: Colloidal gold; Immunochromatographic strip; Monoclonal antibody; Streptococcus agalactiae; Tilapia