title: Light-scattering sensor for real-time identification of Vibrio parahaemolyticus, Vibrio vulnificus and Vibrio cholerae colonies on solid agar plate.
abstract: The three most common pathogenic species of Vibrio, Vibrio cholerae, Vibrio parahaemolyticus and Vibrio vulnificus, are of major concerns due to increased incidence of water- and seafood-related outbreaks and illness worldwide. Current methods are lengthy and require biochemical and molecular confirmation. A novel label-free forward light-scattering sensor was developed to detect and identify colonies of these three pathogens in real time in the presence of other vibrios in food or water samples. Vibrio colonies grown on agar plates were illuminated by a 635 nm laser beam and scatter-image signatures were acquired using a CCD (charge-coupled device) camera in an automated BARDOT (BActerial Rapid Detection using Optical light-scattering Technology) system. Although a limited number of Vibrio species was tested, each produced a unique light-scattering signature that is consistent from colony to colony. Subsequently a pattern recognition system analysing the collected light-scatter information provided classification in 1-2 min with an accuracy of 99%. The light-scattering signatures were unaffected by subjecting the bacteria to physiological stressors: osmotic imbalance, acid, heat and recovery from a viable but non-culturable state. Furthermore, employing a standard sample enrichment in alkaline peptone water for 6 h followed by plating on selective thiosulphate citrate bile salts sucrose agar at 30°C for ∼ 12 h, the light-scattering sensor successfully detected V. cholerae, V. parahaemolyticus and V. vulnificus present in oyster or water samples in 18 h even in the presence of other vibrios or other bacteria, indicating the suitability of the sensor as a powerful screening tool for pathogens on agar plates.
authors.affiliation: Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, IN, USA.
authors.forename: Karleigh
authors.initials: K
authors.lastname: Huff
authors.forename: Amornrat
authors.initials: A
authors.lastname: Aroonnual
authors.forename: Amy E Fleishman
authors.initials: AE
authors.lastname: Littlejohn
authors.forename: Bartek
authors.initials: B
authors.lastname: Rajwa
authors.forename: Euiwon
authors.initials: E
authors.lastname: Bae
authors.forename: Padmapriya P
authors.initials: PP
authors.lastname: Banada
authors.forename: Valery
authors.initials: V
authors.lastname: Patsekin
authors.forename: E Daniel
authors.initials: ED
authors.lastname: Hirleman
authors.forename: J Paul
authors.initials: JP
authors.lastname: Robinson
authors.forename: Gary P
authors.initials: GP
authors.lastname: Richards
authors.forename: Arun K
authors.initials: AK
authors.lastname: Bhunia
mesh_terms: D000362:Agar; D001431:Bacteriological Techniques / Q000379:methods*; D003470:Culture Media / Q000737:chemistry; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D005516:Food Microbiology; D008027:Light; D008969:Molecular Sequence Data; D012680:Sensitivity and Specificity; D017422:Sequence Analysis, DNA; D013997:Time Factors; D014734:Vibrio cholerae / Q000302:isolation & purification*; D014736:Vibrio parahaemolyticus / Q000302:isolation & purification*; D041261:Vibrio vulnificus / Q000302:isolation & purification*; D014871:Water Microbiology
chemical_list: D003470:Culture Media; D004269:DNA, Bacterial; D000362:Agar