WO1996038729A1 - Pathogen assay method - Google Patents
Pathogen assay method Download PDFInfo
- Publication number
- WO1996038729A1 WO1996038729A1 PCT/SE1996/000721 SE9600721W WO9638729A1 WO 1996038729 A1 WO1996038729 A1 WO 1996038729A1 SE 9600721 W SE9600721 W SE 9600721W WO 9638729 A1 WO9638729 A1 WO 9638729A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- pathogen
- antibody
- sample
- salmonella
- sensor surface
- Prior art date
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/48—Biological material, e.g. blood, urine; Haemocytometers
- G01N33/50—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing
- G01N33/53—Immunoassay; Biospecific binding assay; Materials therefor
- G01N33/569—Immunoassay; Biospecific binding assay; Materials therefor for microorganisms, e.g. protozoa, bacteria, viruses
- G01N33/56911—Bacteria
- G01N33/56916—Enterobacteria, e.g. shigella, salmonella, klebsiella, serratia
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/48—Biological material, e.g. blood, urine; Haemocytometers
- G01N33/50—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing
- G01N33/53—Immunoassay; Biospecific binding assay; Materials therefor
- G01N33/569—Immunoassay; Biospecific binding assay; Materials therefor for microorganisms, e.g. protozoa, bacteria, viruses
Definitions
- the present invention relates to a novel assay method for detecting pathogens, especially in foods.
- the conventional cultural method for the detection of pathogens like Salmonella and Listeria requires at least five days to isolate and identify the organism from a food product.
- Salmonella and Listeria are often present in low numbers, largely outnumbered by competing organisms, and occasionally in a stressed state.
- the method therefore includes an initial non-selective pre-enrichment stage designed to allow the resuscitation and growth of the target pathogen.
- the subsequent selective enrichment stage utilises growth media that are inhibitory to competitor cells whilst still maintaining or allowing the growth of the target organism.
- the selective enrichment process aims to improve the ratio of Salmonella or Listeria to competitor cells. Colonies are then isolated from the enriched culture by plating on to selective and differential agar media. Any presumptive-positive colony is then confirmed biochemically and identified serologically. While cultural techniques for the microbiological examination of foods have high sensitivity (capable of detecting one viable cell) , they are time-consuming and highly labour- and material-intensive.
- the available immunoassays of the enzyme-linked immunosorbent assay (ELISA) type for Salmonella are to be performed on selectively enriched samples (48-h culture) and comprise heat-solubilising Salmonella antigen, adding the antigen-containing broth to antibody-coated wells of a microtitre plate and incubating, adding antibody-enzyme conjugate, and after incubation adding substrate and reading absorbance.
- ELISA enzyme-linked immunosorbent assay
- the object of the present invention is to provide a pathogen assay which together with a rapid assay protocol has a sufficiently low detection limit, such as 10 ⁇ -10 ⁇ cfu/ml, to permit detection of pathogens in contaminated foods without 24-h selective enrichment of the food sample, and therefore within a single working day (less than 24 h) .
- the present invention in a broad aspect provides a method for detecting a pathogen in a sample, comprising the steps of:
- the antibody is preferably added in excess of the amount corresponding to the (expected) maximum amount of pathogen to leave unbound antibody in the reaction mixture.
- pathogen as used herein comprises not only bacteria, but also virus, fungi and protozoa.
- the method may, of course, also be applied to samples of other origin, such as, e.g., samples for clinical assays, e.g., blood, urine, etc.
- Exemplary of common foodborne pathogens are Salmonella and Listeria .
- Adequate pre-enrichment (and optionally 6-h selective enrichment) procedures for food samples to reach a pathogen level of about 10 ⁇ -10 ⁇ cfu/ml as mentioned above are well-known to those skilled in the art.
- the removal of the pathogen from the antibody reaction mixture is preferably performed by filtration or centrifugation. Suitable filters for this purpose are known to a person skilled in the art and will not be described in detail herein.
- the technique chosen for detecting the excess antibody in the pathogen-free solution is not critical per se.
- the solution is contacted with an optical sensor surface having immobilized thereon a receptor, such as an antibody, for the primary antibody, and the change in refractive index at the surface related to binding of primary antibody present in the solution to the sensor surface is measured.
- the contacting of the sample with the surface is performed by passing the sample over the surface utilizing a liquid flow system, i.e. a flow cell.
- further sensitivity in the assay may be obtained by using a secondary reagent capable of binding to the primary antibody bound to the sensor surface.
- a tertiary reagent may be used which binds to the secondary reagent.
- Binding of the receptor, such as an antibody, to the surface may be carried out in conventional ways well-known to those skilled in the art. If, for example, the optical surface has a polymeric organic layer at its surface, the receptor may be directly covalently bound to the surface using known linker reagents. Alternatively, an intermediate ligand, such as an antibody, which binds the receptor may first be covalently bound to the surface before this bound intermediate ligand is exposed to the receptor for the analyte to bind this to the surface. It will be appreciated that covalent and/or affinity bonding may be effective in binding the receptor to the surface. However, when the receptor is bound to the surface, it is important that its ability to bind the ligand, i.e. in this case the primary antibody, should remain unchanged.
- the term antibody as used herein is to be interpreted broadly.
- the antibody may be a fragment thereof, such as an Fab fragment, an Fv fragment, a single chain fragment (scFv) , a single heavy chain or even a peptide (based on the nucleotide sequence of the antibody gene) having binding activity.
- the antibodies which may be used in the invention may be obtained by conventional methods and are many times commercially available. Although polyclonal antibodies may conveniently be used in the method of the invention, monoclonal antibodies may be preferred at least in certain cases for their greater specificity.
- the measurement of the change in refractive index at the surface may advantageously be based on evanescent wave sensing, such as surface plasmon resonance spectroscopy (SPRS) , Brewster angle refractometry, critical angle refractometry, frustrated total reflection (FTR) , evanescent wave ellipsometry, scattered total internal reflection (STIR) , optical wave guide sensors, evanescent wave based imaging, such as critical angle resolved imaging, Brewster angle resolved imaging, SPR angle resolved imaging, etc.
- the measurement is based on surface plasmon resonance. This technique is described, inter alia, in EP-A-0305109, EP-A-0267142 and WO-A- 90/05295.
- the optical surface which is used in the measurement based on surface plasmon resonance preferably comprises a gold film and a hydrogel bound to the gold film, as described in WO 90/05303.
- This type of optical surface may easily be regenerated so that a single surface may be used for many analyses. The overall cost per analysis can therefore be reduced considerably.
- Suitable apparatus incorporating such an optical surface is the BIAcore® system available from Pharmacia Biosensor AB, (Uppsala, Sweden) the methods of operation of which are described in the BIAcore® Methods Manual (Pharmacia Biosensor AB) .
- a flow system passes the sample over a replaceable sensor chip forming one wall of a flow cell.
- the sensor chip supports a gold layer which typically has a thickness of 50 nm.
- a carboxylated dextran is bound to the gold layer via a linker layer. To this dextran layer the receptor for the primary antibody may be bound.
- Fig. 1 is a diagram showing the dose-response curve for S. enteritidis and the response of C. freundii obtained by the method of the invention in the same biosensor flow cell;
- Fig. 2 is diagram showing the dose-response curve for S. typhimurium and the response of C. freundii obtained by the method of the invention in the same biosensor flow cell;
- Fig. 3 is a diagram showing the dose-response curve for S. napoli and the response of 5 non-salmonellae obtained by the method of the invention in the same biosensor flow cell;
- Fig. 4 is a diagram showing the dose-response curve for S. Stanley and the response of 3 non-salmonellae obtained by the method of the invention in the same biosensor flow cell;
- Fig. 5 is a diagram showing the dose-response curve for S. thompson and the response of 4 non-salmonellae obtained by the method of the invention in the same biosensor flow cell
- Fig. 6 is a diagram showing the dose-response curve for S. typhimurium and the response of S. enteri tidis, C. freundii and E. coli obtained by the method of the invention in the same biosensor flow cell and using a monoclonal as primary antibody
- Fig. 7 is a diagram showing the dose-response curves for three Listeria serotypes and the response of three non- listeriae obtained by the method of the invention.
- Fig. 8 is a diagram showing the dose-response curves for five Salmonella serotypes and the response of 10 non- salmonellae obtained using a commercial prior art
- Salmonella ELISA (Salmonella-Tek; Organon) .
- Hepes buffered saline HBS, Pharmacia Biosensor AB
- HBS Hepes buffered saline
- NaCl sodium chloride
- EDTA ethylenediaminetetraacetic acid
- KPL Bactrace anti -Salmonella CSA-1 (Kirkegaard & Perry Laboratories) , below referred to as "KPL Bactrace"
- Pharmacia Biosensor's recommended protocol was used for this purpose and involved the reagents (NHS, EDC and ethanolamine) contained in the amine coupling kit (code no. BR-1000-50, Pharmacia Biosensor AB) .
- the carboxylated dextran surface was initially activated using a 35 ⁇ l (flow rate of 5 ⁇ l/min) injection of N-hydroxysuccinimide (NHS) and N-ethyl- N ⁇ (dimethylaminepropyl) carbodiimide (EDC) in distilled water (0.05 M NHS/0.2 M EDC), across a flow cell surface. This was then followed by an injection (35 ⁇ l) of the antibody in 10 mM sodium acetate buffer, pH 5, and a subsequent injection (35 ⁇ l) of 1 M ethanolamine hydrochloride.
- NHS N-hydroxysuccinimide
- EDC dimethylaminepropyl carbodiimide
- TAB Trypticase Soya Broth
- the cultures were then diluted (serial decimal) in HBS and enumerated by plating 0.1 ml on to Trypticase Soya Agar (TSA) .
- TSA Trypticase Soya Agar
- Regeneration of the sensor surface The regeneration conditions were optimised for each anti- Salmonella and anti-Listeria antibody tested. This was achieved by screening a range of potential regeneration solutions, as specified in the BIAcoreTM user manual, in order to find the best possible solution that completely dissociated the antibody from the sensor surface.
- the capture antibody e.g. RAGF a j-, was immobilised to the sensor surface and the anti-Salmonella antibody, e.g.
- KPL Bactrace was injected using the manual command mode to allow binding to the biosensor surface. Then a weak regeneration solution was injected for 1 in and the degree of regeneration monitored. It was found that for KPL Bactrace, for example, the best regeneration solution was 50 mM NaOH.
- Varying levels of an anti- Salmonella antibody were reacted with a high level (approximately 10 ⁇ cfu/ml) of a Salmonella culture in order to determine the level of primary antibody required to give a minimum relative response in the BIAcore®.
- the mixture was then filtered with a 0.22 ⁇ m Sartorius filter to remove excess primary antibody from antibody bound to the bacterial cells, and 15 ⁇ l of the filtrate containing the separated excess primary antibody were injected over the sensor surface coated with the corresponding capture antibody. The sensor surface was then regenerated. The time to first result was 30 min. The higher the level of
- Figs. 1 to 5 show obtained response curves for S. enteri tidis, S. typhimurium, S. napoli , S. Stanley and S. thompson, respectively, together with the response of various non-salmonellae challenged at approximately 10 ⁇ cfu/ml in the same flow cell.
- a polyclonal antibody KPL Bactrace
- Rabbit anti-goat i Gfak fragment (RAGF a j-,) was used as capture antibody on the sensor surface, and regeneration was performed with 50 mM sodium hydroxide, 2x1 min pulses.
- the detection limit for all five Salmonella serotypes was in the range lO ⁇ -io ⁇ cfu/ml.
- Fig. 6 shows the detection of Salmonella using a monoclonal anti-Salmonella (Serotec) as primary antibody and goat anti-mouse IgGf a k fragment (GAMFaj-,) as capture antibody on the sensor surface.
- Regeneration of the GAMF gj -, sensor surface reacted with the primary antibody was performed using a combination of 1x15 ⁇ l formic acid (1M) , 1x5 ⁇ l NaOH (2.5 mM) and 1x15 ⁇ l formic acid (1M) pulses. It is seen from the dose-response curve for S. typhimurium shown in Fig. 6 that no cross-reaction was observed for C. freundii and E. coli tested at approximately 10 ⁇ cfu/ml. A S. enteri tidis control at approximately 10 ⁇ cfu/ml was also successfully detected.
- EXAMPLE 3 Commercial Salmonella EL SA (comparative) Bacterial cultures were prepared as in Example 1 above, and five Salmonella serotypes and responses of ten non- Salmonella were detected by a commercial Salmonella assay, "Salmonella-Tek ELISA", using the following protocol.
- 100 ⁇ l samples were pipetted into wells of a microtitre plate. The samples were then incubated at 37°C for 30 min. After washing six times with wash solution, 100 ⁇ l conjugate were added and incubated at 37°C for 30 min. The wells were then washed six times, and 100 ⁇ l of substrate were added and incubated at room temperature for 30 min. 100 ⁇ l of stop solution were then added and the absorbance was read at 450 nm. The time to first result was 2 h.
Abstract
Description
Claims
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP8536413A JPH11506002A (en) | 1995-06-02 | 1996-05-31 | Pathogen assay method |
EP96917777A EP0832434A1 (en) | 1995-06-02 | 1996-05-31 | Pathogen assay method |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
SE9502024-4 | 1995-06-02 | ||
SE9502024A SE9502024D0 (en) | 1995-06-02 | 1995-06-02 | Pathogen assay method |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1996038729A1 true WO1996038729A1 (en) | 1996-12-05 |
Family
ID=20398495
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/SE1996/000721 WO1996038729A1 (en) | 1995-06-02 | 1996-05-31 | Pathogen assay method |
Country Status (4)
Country | Link |
---|---|
EP (1) | EP0832434A1 (en) |
JP (1) | JPH11506002A (en) |
SE (1) | SE9502024D0 (en) |
WO (1) | WO1996038729A1 (en) |
Cited By (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2004088318A1 (en) * | 2003-04-04 | 2004-10-14 | Biacore Ab | Method and kit for cell analyte assay |
US6833920B2 (en) | 2000-07-11 | 2004-12-21 | Maven Technologies Llc | Apparatus and method for imaging |
US6859280B2 (en) | 2000-07-11 | 2005-02-22 | Maven Technologies Llc | Imaging apparatus and method |
US7023547B2 (en) | 2000-07-11 | 2006-04-04 | Maven Technologies, Llc | Apparatus including a biochip for imaging of biological samples and method |
US7193711B2 (en) | 2000-07-11 | 2007-03-20 | Maven Technologies, Llc | Imaging method and apparatus |
US7518724B2 (en) | 2000-07-11 | 2009-04-14 | Maven Technologies | Image acquisition, processing, and display |
US7563587B2 (en) * | 2003-04-04 | 2009-07-21 | Ge Healthcare Bio-Sciences Ab | Method and kit for cell analyte assay |
US7799558B1 (en) | 2007-05-22 | 2010-09-21 | Dultz Shane C | Ligand binding assays on microarrays in closed multiwell plates |
US7863037B1 (en) | 2007-04-04 | 2011-01-04 | Maven Technologies, Llc | Ligand binding assays on microarrays in closed multiwell plates |
US7867783B2 (en) | 2007-02-22 | 2011-01-11 | Maven Technologies, Llc | Apparatus and method for performing ligand binding assays on microarrays in multiwell plates |
US7981664B1 (en) | 2008-05-22 | 2011-07-19 | Maven Technologies, Llc | Apparatus and method for performing ligand binding assays on microarrays in multiwell plates |
US8039270B2 (en) | 2008-05-22 | 2011-10-18 | Maven Technologies, Llc | Apparatus and method for performing ligand binding assays on microarrays in multiwell plates |
CN105823876A (en) * | 2016-03-18 | 2016-08-03 | 南昌大学 | Salmonella detection method |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0496345A1 (en) * | 1991-01-22 | 1992-07-29 | NAGASE & COMPANY, LTD. | Method for detecting and quantifying cariogenic bacteria |
-
1995
- 1995-06-02 SE SE9502024A patent/SE9502024D0/en unknown
-
1996
- 1996-05-31 WO PCT/SE1996/000721 patent/WO1996038729A1/en not_active Application Discontinuation
- 1996-05-31 EP EP96917777A patent/EP0832434A1/en not_active Withdrawn
- 1996-05-31 JP JP8536413A patent/JPH11506002A/en active Pending
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0496345A1 (en) * | 1991-01-22 | 1992-07-29 | NAGASE & COMPANY, LTD. | Method for detecting and quantifying cariogenic bacteria |
Non-Patent Citations (2)
Title |
---|
INTERNATIONAL JOURNAL OF FOOD MICROBIOLOGY, Volume 12, 1991, S. NOTERMANS et al., "Immunological Methods for Detection of Foodborne Pathogens and Their Toxins", pages 91-102. * |
JOURNAL OF FOOD PROTECTION, Volume 53, No. 10, October 1990, CELINE MORISSETTE et al., "Simple and Rapid Inhibition Enzyme Immunoassay for the Detection of Staphylococcal Enterotoxin B in Foods", pages 834-840. * |
Cited By (15)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7193711B2 (en) | 2000-07-11 | 2007-03-20 | Maven Technologies, Llc | Imaging method and apparatus |
US7518724B2 (en) | 2000-07-11 | 2009-04-14 | Maven Technologies | Image acquisition, processing, and display |
US6859280B2 (en) | 2000-07-11 | 2005-02-22 | Maven Technologies Llc | Imaging apparatus and method |
US6882420B2 (en) | 2000-07-11 | 2005-04-19 | Maven Technologies, Llc | Apparatus and method for imaging |
US7002686B2 (en) | 2000-07-11 | 2006-02-21 | Maven Technologies Llc | Apparatus and method for imaging |
US7023547B2 (en) | 2000-07-11 | 2006-04-04 | Maven Technologies, Llc | Apparatus including a biochip for imaging of biological samples and method |
US6833920B2 (en) | 2000-07-11 | 2004-12-21 | Maven Technologies Llc | Apparatus and method for imaging |
US7563587B2 (en) * | 2003-04-04 | 2009-07-21 | Ge Healthcare Bio-Sciences Ab | Method and kit for cell analyte assay |
WO2004088318A1 (en) * | 2003-04-04 | 2004-10-14 | Biacore Ab | Method and kit for cell analyte assay |
US7867783B2 (en) | 2007-02-22 | 2011-01-11 | Maven Technologies, Llc | Apparatus and method for performing ligand binding assays on microarrays in multiwell plates |
US7863037B1 (en) | 2007-04-04 | 2011-01-04 | Maven Technologies, Llc | Ligand binding assays on microarrays in closed multiwell plates |
US7799558B1 (en) | 2007-05-22 | 2010-09-21 | Dultz Shane C | Ligand binding assays on microarrays in closed multiwell plates |
US7981664B1 (en) | 2008-05-22 | 2011-07-19 | Maven Technologies, Llc | Apparatus and method for performing ligand binding assays on microarrays in multiwell plates |
US8039270B2 (en) | 2008-05-22 | 2011-10-18 | Maven Technologies, Llc | Apparatus and method for performing ligand binding assays on microarrays in multiwell plates |
CN105823876A (en) * | 2016-03-18 | 2016-08-03 | 南昌大学 | Salmonella detection method |
Also Published As
Publication number | Publication date |
---|---|
JPH11506002A (en) | 1999-06-02 |
EP0832434A1 (en) | 1998-04-01 |
SE9502024D0 (en) | 1995-06-02 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
Balasubramanian et al. | Lytic phage as a specific and selective probe for detection of Staphylococcus aureus—A surface plasmon resonance spectroscopic study | |
Bouguelia et al. | On-chip microbial culture for the specific detection of very low levels of bacteria | |
Dover et al. | Recent advances in peptide probe-based biosensors for detection of infectious agents | |
Waswa et al. | Direct detection of E. coli O157: H7 in selected food systems by a surface plasmon resonance biosensor | |
Waswa et al. | Rapid detection of Salmonella enteritidis and Escherichia coli using surface plasmon resonance biosensor | |
Cho et al. | In-situ immuno-gold nanoparticle network ELISA biosensors for pathogen detection | |
Howe et al. | A comparison of protocols for the optimisation of detection of bacteria using a surface acoustic wave (SAW) biosensor | |
Abdel-Hamid et al. | Highly sensitive flow-injection immunoassay system for rapid detection of bacteria | |
Rasooly | Surface plasmon resonance analysis of staphylococcal enterotoxin B in food | |
Taylor et al. | Comparison of E. coli O157: H7 preparation methods used for detection with surface plasmon resonance sensor | |
Chen et al. | Label-free screening of foodborne Salmonella using surface plasmon resonance imaging | |
Seo et al. | Development of a rapid response biosensor for detection of Salmonella typhimurium | |
Kumar et al. | Recent advances in biosensor based diagnosis of urinary tract infection | |
EP0832434A1 (en) | Pathogen assay method | |
Mazumdar et al. | Surface plasmon resonance (SPR) as a rapid tool for serotyping of Salmonella | |
Yang et al. | Campylobacter spp. detection in the 21st century: A review of the recent achievements in biosensor development | |
WO2014138132A2 (en) | Multi-analyte assay | |
US20100129837A1 (en) | Methods of capturing bacterial whole cells and methods of analyzing samples for bacteria | |
Bilitewski | Peer reviewed: Can affinity sensors be used to detect food contaminants? | |
Wang et al. | Label-free detection of B. anthracis spores using a surface plasmon resonance biosensor | |
Skottrup et al. | Rapid determination of Phytophthora infestans sporangia using a surface plasmon resonance immunosensor | |
Kim et al. | Salmonella detection with a direct-binding optical grating coupler immunosensor | |
Becheva et al. | Rapid immunofluorescence assay for staphylococcal enterotoxin A using magnetic nanoparticles | |
EP2904394A1 (en) | Multi-analyte assay | |
Pohanka et al. | Piezoelectric immunosensor for the direct and rapid detection of Francisella tularensis |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AK | Designated states |
Kind code of ref document: A1 Designated state(s): JP US |
|
AL | Designated countries for regional patents |
Kind code of ref document: A1 Designated state(s): AT BE CH DE DK ES FI FR GB GR IE IT LU MC NL PT SE |
|
DFPE | Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101) | ||
121 | Ep: the epo has been informed by wipo that ep was designated in this application | ||
ENP | Entry into the national phase |
Ref country code: JP Ref document number: 1996 536413 Kind code of ref document: A Format of ref document f/p: F |
|
WWE | Wipo information: entry into national phase |
Ref document number: 1996917777 Country of ref document: EP |
|
WWP | Wipo information: published in national office |
Ref document number: 1996917777 Country of ref document: EP |
|
WWW | Wipo information: withdrawn in national office |
Ref document number: 1996917777 Country of ref document: EP |