Food Safety NewsLetter - FoodHACCP.com
12/11/2002
Issue 32

Sponsors


IGEN

Sponsors
Q/A

 

To receive
Free Newsletter,
apply Free
Membership

Contact Us

 

For Main Site
Click here

 

 

Researchers uncover methods to eliminate Listeria bacteria
USDA-funded study effective in reducing harm in cold hot dogs

source from: Tristan Hinderliter Kansas State Collegian
http://www.kstatecollegian.com/
It's time to warn your roommate who likes to eat hot dogs directly out of the package -- by not reheating hot dogs, he could be exposing himself to deadly bacteria.
Researchers at the K-State Food Science Institute have discovered an effective way of reheating hot dogs to eliminate any such harmful bacteria. Heating a hot dog wrapped in a paper towel in the microwave for 60 seconds is an effective way to eliminate Listeria monocytogenes, said Curtis Kastner, director of the K-State Food Science Institute. "Listeria outbreaks are fairly low, but the reason it's so significant is because the percentage of deaths that result from that organism are the highest," Kastner said. "So if you get it, it's a pretty lethal thing." Listeria causes 2,500 serious illnesses and 500 deaths each year. It primarily affects pregnant women, older adults and persons with weakened immune systems, according to a USDA news release. Teresa Ortega, a doctoral graduate student, carried out the experiment. She took already-packaged hot dogs from a grocery store and put Listeria on them in a laboratory to see which reheating process would most effectively kill the bacteria. "Listeria is around us -- it can get on the product," Kastner said. "It could be a contaminant just because you've taken it out of its casing and it's exposed to the environment and Listeria gets on it." Ortega compared Listeria reductions of seven ways to reheat a hot dog, including common household practices such as boiling the frank in water for 30 seconds, boiling it for 60 seconds, cooking it in an electric oven for 2 minutes, cooking it in an electric oven for 5 minutes, microwaving it for 60 seconds and microwaving it in water for 60 seconds. However, she found that microwaving the hot dog for 60 seconds wrapped in a paper towel was the most effective way of the seven ways she tried for eliminating Listeria. "The way a microwave heats, it causes the surface of that product to get warm, and then it begins to emit steam. If you wrap something around that, that steam that comes off is concentrated right at the surface and you can get an additional effect," Kastner said. Hot dog manufacturers may use a process like a steam-pasteurizer to kill any possible Listeria on hot dogs after they are packaged, Kastner said, but you can do the same thing at home. "You don't have to have Oscar Mayer run the package through this steam-pasteurizer -- they might want to -- but then, when you've got it home, you can take it and heat it in hot water or cook it in the microwave to kill the bacteria yourself," he said. Heating hot dogs to kill any bacteria that could have gotten on the surface is safer than eating them right out of the package, Kastner said. The USDA funded K-State's hot dog experiment. The USDA Food Safety and Inspection Service has issued a "zero tolerance" for Listeria monocytogenes in ready-to-eat meat and poultry products. Results of the study could be used on product labels, advising consumers how to best reheat products to eliminate possible bacteria. However, Kastner said results would most likely be disseminated through the K-State Research and Extension service. The research took place between July 2001 and June 2002. Kastner said this experiment is the most up-to-date project concerning elimination of Listeria on hot dogs.
Other principle researchers on the project were Harshavardhan Thippareddi, Randall Phebus and James Marsden, all of the K-State Food Science Institute.

FIRST WORLD CONGRESS ON FOOD IRRADIATION
December 7, 2002
http://www.foodsafe.msu.edu/congress.html
Meeting the Challenges of Food Safety and Trade
Organized by the National Food Safety & Toxicology Center (NFSTC), in co-operation with: Grocery Manufacturers of America (GMA) Food Marketing Institute (FMI) Institute of Food Technologists (IFT) International Union of Food Science and Technology (IUFoST) Financial contributors also include:
MDS Nordion SureBeam Inc. Steris Inc. Minnesota Beef Council
Taking note of these and other issues and developments, the First World Congress on Food Irradiation: Meeting the Challenge of International Trade will attempt to examine and assess the future of food irradiation through a comprehensive programme examining:
Global situation and outlook on the use of irradiation as a sanitary and phytosanitary treatment Major markets and market trends
Technological developments: irradiation facilities, new products, value addition, quality assurance Investment opportunities
Visit to a commercial food irradiator Buyer-seller meet (business session) and technical session. VENUE: Chicago, 5-7 May 2003
CURRENT TRENDS AND FUTURE OUTLOOK Food irradiation is increasingly accepted and applied as a sanitary and phytosanitary treatment for many types of food products. With pending further regulatory approvals of major food trading nations such as the USA,
Australia/New Zealand and the European Union, trade in commodities such as irradiated fresh fruits and vegetables, spices and dried vegetable seasonings, meat and poultry, seafood, etc. should increase significantly in the near future. Several Asian, Africa and Latin American countries have already strengthened
their regulatory infrastructure and are in a position to implement
international trade in some irradiated food commodities immediately. Urgent actions are required to inform various national/regional and international food regulatory agencies, trade associations and their members of the benefits which they can expect from irradiation. At the same time, it is important to invite potential importers of irradiated food products to meet with the exporters to plan future activities under the guidance of world leaders and experts in food irradiation. The best place for them to converge is at the First World Congress on Food Irradiation.
WHO SHOULD ATTEND
Growers, food producers/processors, shippers/packers, distributors,
wholesalers, retailers, importers, exporters, food service, regulatory
authorities related to sanitary and phytosanitary treatment for food,
irradiation providers/equipment manufacturers, scientists, consumer
organizations.
WHAT ARE IN-STORE? AT THIS WORLD CONGRESS
International Trade Conference: Get the latest and fresh idea from
national/international experts on food irradiation on the benefits which irradiation can bring to implement its use as a food safety and trade measure, expand business and enter new markets, and to develop new ideas. Witness how food irradiation merges into the fast lane and prepare your business for the future with new and ever-exciting information you need. Make high-speed networking with others who can expand your business and productivity.
Irradiated Food Exposition: The top companies in the business of food irradiation including irradiation service providers, irradiated food
producers, food processors and companies which already marketed their irradiated food, retailers, will be invited to bring new ideas and solutions through an exposition. Find the best and innovative ideas in marketing your products through irradiation. Networking with your current contacts and connect with new ones to expand the trade of your commodities. Tour of a Commercial Food Irradiator: Join other colleagues to visit a commercial food irradiator in operation to see how a simple and effective technology can add value to your products - Seeing is believing! Take the idea home to put it into action in your business. Supermarket Tour: How many people have seen irradiated food being sold at retail? Hit the road during the Congress to see how this is done and how well it is accepted by consumers in a local supermarket. Develop a strategy how to market irradiated products in your country or to export them
overseas.
HOTEL INFORMATION-
To reserve a hotel room, contact the Congress Plaza Hotel, 520 South Michigan Ave., Chicago, IL 60605. Participants can call anytime to make their hotel reservations (They must give the NFSTC symbol) to receive the room prices of $120 single and $140 double. Call 1-800-635-1666, or please go to www.congressplazahotel.com.
Blocks are also reserved at The Hyatt Regency Chicago (newly renovated) and Sheraton Chicago. Rooms at the Hyatt are $176 and rooms at the Sheraton are $190. Those rooms will be available to reserve online through FMI after Jan. 1, 2003. Please check back then.

Food Safety General News
12/10. FSIS NOTICES
12/10. RECALL PUBLIC MEETING THIS WEEK
12/10. UNDERFUNDED CAROLINA FOOD INSPECTIONS FALL WELL SHORT OF FDA -
12/10. THE ABCS OF X-RAY FOOD: AS HEALTH CANADA POLLS THE NATION AB
12/10. STUDY ON BACTERIA IN MINNESOTA-RAISED POULTRY AT ODDS WITH
12/10. NMA COMMENTS ON E. COLI O157:H7
12/10. RECALLS
12/10. PRESS' PALATE FOR LM
12/10. EU agrees on traceability, labelling of food containing GMOs
12/10. BABY'S DEATH LEADS TO LISTERIA WARNING
12/10. BSE case found in Northern Ireland
12/10. BUTCHERS PROVE THEY ARE UP TO THE JOB
12/10. Food Standards Agency reports specified risk material found
12/10. MEAT HYGIENE SERVICE AUDITED
12/10. Canadian HorticulturaL Council Meets to Further On-Farm Food Safety Initiatives
12/10. Focus on Risk is Appropriate in USDA Directive on Listeria
12/10. Local chicken and turkey products contain antibiotic resista
12/09. VICTORIA COURT ISSUES $4,000 IN FINES FOR DETENTION VIOLATIO
12/09. SALE OF MAPLE SYRUP CONTAINING PARAFORMALDEHYDE RESIDUES - S
12/09. HUTTERIAN BRETHREN OF PINCHER CREEK FINED FOR ILLEGAL MEAT S
12/09. ASK THE HEALTH INSPECTOR?
12/09. MORE THAN HALF SURVIVORS FEEL AFTEREFFECTS OF CURRY POISONIN
12/09. FIRST WORLD CONGRESS ON FOOD IRRADIATION
12/09. HOW TO KEEP PRODUCE KICKING AFTER THE CLOCK STARTS TICKING
12/09. SHELLFISH HARVEST CLOSURES ON THE PACIFIC COAST INTENDED TO
12/09. NORWALK VIRUS AND STEPS TO PROTECT AGAINST ILLNESS
12/09. USDA to re-inspect shuttered IBP/Tyson's Lakeside beef plant
12/09. 10-minute consultation: food allergy
12/08. USDA revises Bio-Rad test permit
12/08. Irradiated burgers to appear at local Dairy Queens
12/08. FOOD SURVEY SHOWS DROP IN PAHS
12/08. FSIS DIRECTIVE OFFERS NEW INSTRUCTIONS FOR AMR SAMPLING
12/08. Trouble with ephedra
12/07. Denver restaurant inspectors check out eateries
12/07. How Dietz & Watson relies on cleaning to prevent meat recall
12/07. Perspective by Editor of Meat Processing North American Edit -
12/07. GM expert warns of cancer risk from crops
12/07. FSIS ISSUES NOTICE ON MICROBIAL PATHOGEN COMPUTER MODELING I


Reported Shigella cases have increased
By Travis Morse, The Journal-Standard December 10, 2002 http://www.zwire.com/
Spread of the bacterial infection can be slowed with proper hand washing FREEPORT - At least 25 residents of the Stephenson County area have been diagnosed with the bacterial disease Shigella in recent weeks, according to County Health Administrator Jeff Todd. Although no one is reported to have been hospitalized for this condition, Todd said the number of cases is unusually high for this area and is emphasizing prevention measures to stop the spread of the disease.As of yet, Health Department officials have not been able to pinpoint a specific cause for the unusually high number of Shigella cases in the area. Shigella is an acute bacterial disease usually spread through food or person-to-person contact that can cause sudden and severe diarrhea in humans. The local outbreak is not connected to any specific food establishment or other common link, Todd said, and the cases are spread out in the area."This seems to be very disjointed, fragmented throughout the community," Todd said. "We don't have a source. Over two dozen cases have been reported from the medical community, but we have not been able to identify any common link among the families."Todd said those afflicted with this disease generally get over their symptoms in a few days. Symptoms can include diarrhea, vomiting and stomach pain. The illness is generally only life threatening to the elderly, infants, those who are already ill, or those with weakened immune systems. Hospitalization may result if there is severe dehydration.Without a source, it is hard to say what caused the outbreak. Todd said the disease is usually spread through fecal/oral transmission from one person to another. This can be caused by people with the illness not washing thoroughly after using the bathroom and then having personal contact with another person or preparing food ingested by others. In other areas, outbreaks of this kind have also been caused by water contamination. This contamination would consist of sewage or fecal matter."These are organisms that are probably always present in the environment," Todd said. "Why they happen to strike out at a particular time is not known. Without finding a single source, the best we can do is treat each case. ... Our guess is this is the obvious result of poor hand-washing technique." Dr. Robert Geller, vice president and medical director of the Freeport Health Network, said he has not been made aware of any individuals who have become seriously ill from the disease. He said the Health Network has reported 21 positive cases, most of them children. So far, Geller said he has not been consulted about any life-threatening cases related to Shigella. "It tells me that all the physicians were quite comfortable taking care of patients," Geller said. Since there is no specific source for the outbreak, local health officials are treating the illness on a case-by-case basis and spreading the word on the importance of good hygiene.Peter Flynn, superintendent of District 145, said last week, he did have letters sent home to parents of children in one classroom at the Jones-Farrar Early Learning Center emphasizing the importance of hand-washing and taking children with symptoms to a doctor. The letters were sent home through this classroom, consisting of 18 to 20 children, because a few of the students in that class had been out sick for a few days with symptoms similar to those associated with Shigella."We did talk to some parents about the importance of hand-washing," Flynn said. "We advised in the letter that if you're child has some of these symptoms, take them to a doctor."Todd said those people in sensitive occupations who have contracted the disease have been put into a suspended work position, which means they are not to return to work until they can show the disease has been properly treated and there is no longer the risk of spreading the illness. Sensitive occupations include hospital workers, day care workers, nursing home workers and food preparation workers.In addition to suspending work, the Health Department is also getting the word out to restaurants and residents about the importance of thorough hand-washing. This is especially important this time of year when there are a lot of family get-togethers where a good deal of food is prepared, Todd said. Todd said he considers thorough hand-washing to include at least 60 seconds of washing with soap and water. This includes cleaning under fingernails.
"We've redoubled our techniques to tell restaurants about the need for hand-washing," Todd said. "Extensive hand-washing can prevent this illness, influenza and other infectious organisms. Proper sanitation is important at home and in food facilities."The Jo Daviess County and Ogle County Health Departments have reported no recent cases of Shigella.According to the Centers for Disease Control and Prevention, there are around 18,000 cases of shigellosis reported in the United States each year. Because a lot of milder cases are not diagnosed or reported, the actual number of infections may be much higher.

ON-Line Slides

Preharvest water and Food Safety
obtained from UC Davis (UCgaps) - http://ucgaps.ucdavis.edu (Trevor V. Suslow, Ph.D.)
Click here to see the slides (PDF file)

Food Safety and Sanitation for Fruit Packers workshop
obtained from PSU Food Safety website - http://foodsafety.cas.psu.edu
Presentations:
Introduction
Microorganisms of Concern in Agriculture
Food Safety Systems
Water
Cross Contamination
Handwashing Facilities, etc.
Postharvest Diseases
Federal-State Inspection Service

Mushroom Sanitation Workshop Review
obtained from PSU Food Safety website
- http://foodsafety.cas.psu.edu
Presentations:
Cold Storage Sanitation - Trevor Suslow, UCDavis
Hand Sanitation - Trevor Suslow, UCDavis
ORP Basics Mushroom Workshop - Trevor Suslow, UCDavis
Basic Microbiology - Linda Harris, UCDavis
Pathogen Testing - Linda Harris, UCDavis
Food Safety Systems - Luke LaBorde, Penn State
Key Sanitation Areas - Luke LaBorde, Penn State
1. Safety of Water
2. Cleaning and Sanitizing Food Contact Surfaces
3. Cross-Contamination
4. Maintenance of Handwashing, Hand Sanitizing, and Toilet Facilities
5. Protection from Adulterants
6. Proper Labeling, Storage, and Use of Toxic Compounds
7. Employee Health Conditions
8. Pest Control

- Biosecurity Challenges: An Industry Perspective
obtained from Meatscience.org

- Prevalence of Escherichia coli O157:H7 in Cattle and During Processing
obtained from Meatscience.org

- HACCP for Food Service Employees

- HACCP Video

- Sanitation Control Procedure Course


OUTBREAK NEWS
12/10. Reported Shigella cases have increased
12/09. Four salmonella cases reported in Boise
12/08. E. COLI O157:H7: PRINCE EDWARD ISLAND (UPDATE)

Sponsors Section
IGEN
The PATHIGEN¢ē Tests are intended for the detection and presumptive identification of E.coli O157, Salmonella, Listeria, and Campylobacter in food and environmental samples. The revolutionary tests utilize the proprietary ORIGEN¢ē Technology to establish a rapid and highly sensitive test for the specific pathogen.

remel
NEW BioSys
The Remel BioSys is an automated bioburden test system that reduces QC testing times by providing rapid, accurate results.

Recall News
12/10. Undeclared sulphites in HAI PEACH, RASPBERRY, APRICOT, and ORANGE JAM
12/10. Publix Grocery Store Ground Beef Products Recall
12/10. Florida Firm Has Recalled Ground Beef Dec 10
12/09. Potential presence of cherry pits in DOLE¢ē LOTS-O-CHERRIES¢ā products
12/09. Marigold Foods Has Recalled Kemps Old Fashioned Chocolate Chip Ice Cream Dec 6
12/09. Campbell's Soup Company Has Recalled Condensed Cream of Mushroom Soup Dec 6
12/09. Frito Lay Has Recalled Potato Chips Dec 6
12/08. Recall Update: Abe Franczoz Bakery Recall is Complete Dec 6
12/08. Recall Update: Polonica Inc MIESZKO Recall is Complete Dec
12/08. Recall Update: Bengal Seafood Peanut and Noodle Snack Mix Recall is Complete Dec 6
12/07. Sutton Place Gourmet Balducci's brand GOLDEN RAISINS Recall is Complete
12/07. Kellogg Has Recalled Kellogg's¢ē Pop-Tarts¢ē Frosted Brown Sugar Cinnamon Dec 6


USDA/FDA News
FSIS Constituent Update/Alert: Updated December 9, 2002
Improving the Recall Process
Improving the Recall Process: Related Documents
Microbial Sampling of RTE Products for FSIS Verification Testing Programs
Microbial Sampling of Ready to Eat (RTE) Products for the FSIS Verification Testing Program
OPPD (Policy) What's New Page: Updated December 9, 2002

New Method

Title: Reagent for the detection of Staphylococcus aureus by agglutination

http://www.pharmcast.com/Patents/Yr2002/
United States Patent: 6,482,602
Issued: November 19, 2002
Inventors: Fournier; Jean-Michel (Paris, FR); Boutonnier; Alain (Paris, FR)
Assignee: Institut Pasteur (Paris, FR)
Appl. No.: 634838
Filed: August 8, 2000
Abstract
Reagents and methods for the detection of Staphylococcus aureus are provided. The reagents contain an antibody that binds to a capsular polysaccharide of type 5 of Staphylococcus aureus, and can be used in methods for detection of oxacillin resistant Staphylococcus aureus that escapes detection by agglutination in the presence of fibrinogen and antibodies directed against protein A of Staphylococcus.
Description of the Invention
The present invention relates to a reagent for the detection of Staphylococcus aureus by agglutination. Various reagents are already known for the detection of Staphylococcus aureus. These reagents are based on the search for either protein A of Staphylococcus or the affinity factor for fibrinogen, or both simultaneously. Protein A is an antigen of protein nature, an external component of the wall of the majority of the strains of Staphylococcus aureus of human origin (85 to 95). By a non-immunological process, protein A binds the Fc fragment of the immunoglobulins, leaving the Fab part free. If strains of Staphylococcus aureus possessing protein A and sheep red blood cells or latex particles sensitized, for example, with rabbit anti-sheep red blood cells serum are placed together, an agglutination visible to the naked eye is observed within a few minutes. The affinity factor for fibrinogen which is attached to the surface of Staphylococcus aureus reacts directly with fibrinogen. This affinity factor for fibrinogen can be determined within a few seconds by placing 7 in contact the strain under study and sheep red blood cells (passive hemagglutination) or latex particles, one or other being coated with fibrinogen. Various published studies show that a certain number of strains of Staphylococcus aureus are not identified by these reagents. Their percentage varies from 1 to 5% when these studies are carried out on all of the Staphylococci aureus isolated. But this percentage of failure is larger when only the strains resistant to oxacillin (or meticillin, are taken into consideration and this percentage attains 25% in a recent study carried out with 73 strains of Staphylococcus aureus resistant to oxacillin (see P. J. Ruane et al., J. Clin. Microbiol. 24, 490, 1986). In a study carried out under the direction of one of the inventors on 183 strains of Staphylococcus aureus isolated from patients in 5 hospitals in Paris and the Paris region, it has been found that 7 strains (4%) are not agglutinated by any of the three reagents used (Staphyslide.RTM., Staphaurex.RTM. and Pastorex.RTM. Staph). If only the 50 strains resistant to oxacillin are considered, it is found that 6 strains (12%) are falsely negative with the commercial reagents. Hence, these results are in agreement with those described in the literature. Two hypotheses may be envisaged to explain the fact that some strains of Staphylococcus aureus are not agglutinated by the commercial reagents:
1) These strains produce protein A in an amount too small for there to be a reaction between this protein and the latex particles adequate to lead to bacterial agglutination.
2) Protein A is produced in normal amounts, but this antigen as well as the affinity factor for fibrinogen are masked by one or more other antigens and are thus inaccessible to the latex particles. In a study carried out under the direction of one of the inventors, it has been shown that the strains non-agglutinated by the latex particles produce as much protein A as the other strains. This result thus makes it possible to eliminate the first hypothesis. It was then shown, by determining the capsular polysaccharide by means of an immunoenzymatic reaction utilizing monoclonal antibodies, that all of the strains non-agglutinated by the latex particles sensitized by fibrinogen and against protein A possess the capsular polysaccharide. Finally, the antigens exposed at the surface of the staphylococcus and, consequently, capable of reacting with the latex particles were studied by immunofluorescence. This study focused, on the one hand, on protein A by utilizing the Fc fragment of human immunoglobulin and pepsinized F(ab')2 fragments of anti-human Fc sheep immunoglobulins labelled with fluorescein) and, on the other, on the capsular polysaccharide (by utilizing mouse monoclonal antibodies of the M isotype specific for the capsular polysaccharide and F(ab')2 fragments of anti-mouse M immunoglobulin goat immunoglobulins labelled with rhodamine. This study clearly showed that protein A is not exposed or then only in very small amount at the surface of the bacteria which are not agglutinated by the latex, and that the surface of these bacteria is, on the other hand, totally masked by the capsular polysaccharide. As a control, it was verified that the strains which are agglutinated by the latex particles do indeed display protein A at their surface.
Thus, this study shows that the capsular polysaccharide synthesized by some strains of Staphylococcus aureus masks all of the bacterium, masks the antigens capable of being recognized by the commercial reagents and thus prevents the identification of these strains as belonging to the Staphylococcus aureus species by the fact of their agglutination by the commercial reagents.
The result of this study and, in particular the fact that the strains of Staphylococcus aureus which do not exhibit protein A at the surface are capsulated strains, the capsular polysaccharides of which mask the protein A has made it possible to design a reagent for the detection of the strains of Staphylococcus aureus which possesses a greater reliability than the known reagents.
A subject of the present invention is thus a reagent for the detection by agglutination of Staphylococcus aureus of the type comprising particles in suspension to which are bound fibrinogen and antibodies recognized by affinity by the protein A of staphylococcus, characterized in that it contains particles in suspension to which are bound at least one antibody recognizing specifically a capsular polysaccharide of Staphylococcus aureus.
Another subject of the present invention is a procedure for the detection by agglutination of Staphylococcus aureus in a sample, which consists of mixing the sample with a reagent according to the invention and of observing whether an agglutination occurs. At present 11 types of capsular polysaccharides have been identified by essentially immunological methods. See in this connection: W. W. Karakawa et al., Capsular polysaccharides of Staphylococcus aureus p. 285-293. In J. B. Robbins, J. C. Hill, and J. C. Sadoff (ed.) Seminars in infectious disease. vol. 4. Bacterial vaccines. Thieme Stratton. Inc. New York; W. W. Karakawa et al. J. Clin. Microbiol. 22: 445-447, 1985; Sompolinsky et al., J. Clin. Microbiol. 22: 828-834, 1985. The purification and the biochemical and immunological characterization of the capsular polysaccharide of type 8 were carried out in 1984 (J. M. Fournier et al., Infect. Immun. 45: 87-93) and those of type 5 in 1987 (J. M. Fournier et al., Ann. Inst. Pasteur/Microbiol. 138: 561-567).
Specific monoclonal antibodies of the capsular polysaccharides 5 and 8 have been described (H. K. Hochkeppel et al., J. Clin. Microbiol. 25: 526-530, 1987, and M. J. Nelles et al., Infect. Immun. 49: 14-10, 1985). Furthermore, epidemiological studies carried out on a large number of strains of Staphylococcus aureus isolated from patients have shown that 70 to 80% of these strains possess one or other of the capsular polysaccharides 5 and 8 (for example R. D. Arbeit et al., Diagn. Miticrobiol. Infect. Dis. 2: 85-91, 1984). Also in the present invention the antibodies recognizing a capsular polysaccharide of Staphylococcus aureus are advantageously constituted by at least antibodies recognizing a capsular polysaccharide of type 5 or 8 and preferably simultaneously by antibodies recognizing a capsular polysaccharide of type 5 and antibodies recognizing a capsular polysaccharide of type 8. But it is obvious that the most reliable diagnostic reagent contains a set of antibodies recognizing the different types of capsular polysaccharides. In the reagent according to the invention, the different antibodies and fibrinogen may be bound to only one suspension of particles or be bound to different suspensions of particles (in a proportion of one or lore types of component per suspension of particles) which are then mixed to constitute the reagent. The particles in suspension used in the reagent according to the invention are in particular latex particles such as polystyrene beads or similar particles, having preferably a size less than 2 micrometers. As an example mention may be made of ESTAPOR particles marketed by the Rhone-Poulenc Company such as particles of polystyrene K 109, having a diameter of 0.8 micrometer, particles of polystyrene having carboxyl groups, PSI 480, having a diameter of 0.8 micrometer. Magnetic gels may also be used such as gels of polyacrylamide and/or agarose containing magnetic particles which are described in FR-A-2 334 106. Gels such as Ultrogel.RTM. and Magnogel.RTM. from the IBF Company may also be used. The antibodies used in the present invention may be animal or human antibodies, polyclonal or monoclonal. The antibodies recognized by affinity by protein A of staphylococcus are, in particular, antibodies of the IgG class. They may be replaced by Fc fragments of these immunoglobulins.In the case of polyclonal antibodies, a human or animal plasma, normal or immunized, containing these antibodies or antibodies purified according to standard methods may be used for the preparation of the reagent. In the case of monoclonal antibodies, a supernatant of a hybridoma culture or ascites fluid prepared in mice, or antibodies in the purified state may be used. In order to bind fibrinogen, a human or animal plasma, normal or hyperimmunized, or fibrinogen purified according to standard methods may be used. The binding of these molecules to the particles in suspension, usually latex, may be accomplished in various ways: the binding may be spontaneous during the course of incubation of the latex particles in a solution containing these molecules, for example an incubation of 30 minutes at 56oC. is often sufficient. this binding can also be carried out by creating a covalent linkage between the antibodies and the carboxylic groups present on some of the latex particles (ESTAPOR PSI 480). It is possible to use, for example, a carbodiimide to establish the covalent linkage.
The concentration of the molecules to be bound to the latex particles, which must be determined for each molecule according to known methods, is usually lower than 200 micrograms per mg of latex. In the case of the use of molecules as components of plasma, a dilution of this plasma to 1/1000 may be used.
Claim 1 of 20 Claims
What is claimed is:
1. A diagnostic kit for the detection by agglutination of Staphylococcus aureus comprising particles in suspension to which are bound:
(A) fibrinogen
(B) antibodies or Fc fragments thereof that have affinity for protein A of Staphylococcus, and
(C) at least one antibody that binds to a capsular polysaccharide of type 5 of Staphylococcus aureus,
wherein said kit can detect oxacillin resistant Staphylococcus aureus that is not detected by said kit in the absence of the antibody that binds to the capsular polysaccharide.

Contact us Click here
Sponsorship Click here
New Membership Application (FREE) Click here

Copyright 2000-2002. (C)FoodHACCP.com
All rights reserved.