title: Gold nanoparticle-based immunochromatographic test for identification of Staphylococcus aureus from clinical specimens.
abstract: BACKGROUND
  Staphylococcus aureus is one of the most important human pathogens, causing both nosocomial and community-acquired infections. Therefore, a method for rapidly detecting for S. aureus would be useful. We describe an analytical system of immunochromatographic assay based on gold nanoparticles developed for the detection of S. aureus in patient specimen.
  
  
  METHODS
  The assay was in the sandwich format, using anti-protein A IgG with 2 distinct specificities. One anti-protein A IgG was immobilized in a defined detection zone on a porous nitrocellulose membrane, while the other anti-protein A IgG was conjugated with gold nanoparticles. The mixture was then passed along the porous membrane by capillary action past the anti-protein A IgG in the detection zone, binding the particles that to which surface protein A was already bound to their surface, yielding a red color.
  
  
  RESULTS
  The sensitivity and specificity in the immunochromatographic test were 100% and 94.7-100% for 130 S. aureus strains and 36 non-S. aureus strains, respectively. The results were comparable to the conventional coagulase test and latex agglutination test of different bacteria.
  
  
  CONCLUSIONS
  This method may be useful for analyzing S. aureus in patient specimen. It was quick, easy to perform, and with a long shelf life at room temperature.
authors.affiliation: Department of Biotechnology and Bioinformatics, College of Arts and Sciences, Asia University, No. 500 Lioufeng Rd., Wufeng, Taichung, 41354 Taiwan, ROC. shhuang@asia.edu.tw
authors.forename: Su-Hua
authors.initials: SH
authors.lastname: Huang
mesh_terms: D000906:Antibodies / Q000737:chemistry; D000937:Antigen-Antibody Reactions; D002846:Chromatography, Affinity / Q000379:methods*; D006046:Gold / Q000737:chemistry*; D006801:Humans; D007074:Immunoglobulin G / Q000737:chemistry; D053758:Nanoparticles / Q000737:chemistry*; D012680:Sensitivity and Specificity; D013203:Staphylococcal Infections / Q000175:diagnosis*; D013205:Staphylococcal Protein A / Q000276:immunology; D013211:Staphylococcus aureus / Q000276:immunology / Q000302:isolation & purification*
chemical_list: D000906:Antibodies; D007074:Immunoglobulin G; D013205:Staphylococcal Protein A; D006046:Gold