title: Optimization of Salmonella Typhi biofilm assay on polypropylene microtiter plates using response surface methodology.
abstract: The objective of this study was to develop an optimized assay for Salmonella Typhi biofilm that mimics the environment of the gallbladder as an experimental model for chronic typhoid fever. Multi-factorial assays are difficult to optimize using traditional one-factor-at-a-time optimization methods. Response surface methodology (RSM) was used to optimize six key variables involved in S. Typhi biofilm formation on cholesterol-coated polypropylene 96-well microtiter plates. The results showed that bile (1.22%), glucose (2%), cholesterol (0.05%) and potassium chloride (0.25%) were critical factors affecting the amount of biofilm produced, but agitation (275 rpm) and sodium chloride (0.5%) had antagonistic effects on each other. Under these optimum conditions the maximum OD reading for biofilm formation was 3.4 (λ600 nm), and the coefficients of variation for intra-plate and inter-plate assays were 3% (n = 20) and 5% (n = 8), respectively. These results showed that RSM is an effective approach for biofilm assay optimization.
authors.affiliation: a Ecobiomaterial Research Laboratory, School of Biological Sciences , Universiti Sains Malaysia , Penang , Malaysia.|b Enteric Diseases Research Cluster, Institute for Research in Molecular Medicine (INFORMM) , Universiti Sains Malaysia , Penang , Malaysia.
authors.forename: M
authors.initials: M
authors.lastname: Ganjali Dashti
authors.affiliation: c Department of Bioprocess Engineering, Faculty of Chemical Engineering , Universiti Teknologi Malaysia, UTM , Skudai , Johor , Malaysia.
authors.forename: P
authors.initials: P
authors.lastname: Abdeshahian
authors.affiliation: a Ecobiomaterial Research Laboratory, School of Biological Sciences , Universiti Sains Malaysia , Penang , Malaysia.
authors.forename: K
authors.initials: K
authors.lastname: Sudesh
authors.affiliation: b Enteric Diseases Research Cluster, Institute for Research in Molecular Medicine (INFORMM) , Universiti Sains Malaysia , Penang , Malaysia.
authors.forename: K K
authors.initials: KK
authors.lastname: Phua
mesh_terms: D018441:Biofilms / Q000187:drug effects / Q000254:growth & development; D005704:Gallbladder; D006801:Humans; D008828:Microbiological Techniques / Q000379:methods / Q000592:standards; D008954:Models, Biological; D011126:Polypropylenes / Q000737:chemistry*; D058996:Quality Improvement; D012485:Salmonella typhi / Q000187:drug effects / Q000502:physiology; D013499:Surface Properties; D014435:Typhoid Fever / Q000175:diagnosis*
chemical_list: D011126:Polypropylenes
keywords: Salmonella Typhi; biofilm assay; in vitro model; optimization; response surface methodology; typhoid fever