Chuck Czuprynski, Ph.D.

Transcription

1 Chuck Czuprynski, Ph.D.

2 Food Safety 1952 Staphylococcus aureus Enterotoxins 79 outbreaks, 3803 cases Clostridium botulinum Botulinum toxins 2 outbreaks, 5 cases Salmonella 42 outbreaks, 1491 cases (includes S. typhi)

3 Food Safety 2013 Estimated 48 million cases per year 9,400,000 by known agents (Scallan et al., 2011) 128,000 hospitalizations, 3036 deaths Viruses Norovirus, Rotavirus 5.5 million cases, usually environmental (e.g. cruise ships) Protozoa Toxoplasma 87,000 cases

4 Food Safety 2013 Bacteria Salmonella 1 million cases, 19,000 hospitalized, 378 deaths Campylobacter 845,000 cases, 8,400 hospitalized, 76 deaths, potential for Guillain-Barre Syndrome (0.1% cases) E. coli STEC (0157 and others) 176,000 cases, 2400 hospitalized, 20 deaths Listeria 1600 cases, 1450 hospitalized, 255 deaths S. aureus enterotoxemia 241,000 cases, 1064 hospitalized, 6 deaths

5 So what has changed in the past 50 years? Less cooking from scratch in the home Busy life-style, people want ready to eat meals, microwave More adventuresome palates desire for different foods Expectation of favorite foods all year long Far better diagnostic tools Computer networks identify outbreaks Pulse-Net implicate food as source of agent

6 Pulsed-field gel electrophoresis (PFGE) High resolution separation of very large DNA fragments (ca Kb) through periodic reorientation of an electric field. 6

7 Human fingerprint Bacterial genomic fingerprint 7

8 Use of PFGE pattern to implicate source of outbreak

9 PulseNet connects similar cases of foodborne illness together, quickly finding outbreaks, and linking these illnesses across states and countries.

10 Human pathogens, cattle and dairy products Salmonella Campylobacter E. coli Listeria Staphylococcus aureus

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12 Human Salmonellosis Estimated 1 million cases/year, 120,000 hospitalizations, 378 deaths Many serotypes Many food types, sources of infection Dramatic foodborne outbreaks (milk- Chicago 1986; peppers/tomatoes 2008; peanut paste 2009) Estimated prevalence of 1.5 to 11% in bulk tank milk

13 Salmonella: Diarrhea in an Adult Holstein Splat too big

14 Invasion cell death hemorrhage & necrosis SEM from Gyles & Thoen, 2 nd edition TEM intracellular Salmonella Normal villi Villus tip Salmonella-affected villi

15 Salmonella in Milk Hill Farms Dairy Chicago (1985) Over 6000 cases over 50%< 10 yr Illinois, Indiana, Iowa, Michigan, Wisconsin Only 2% milk, not other products Post pasteurization contamination cause never determined Recent Raw milk Salmonella outbreaks MN queso fresco

16 Salmonella ice cream outbreak 1994 MN ice cream outbreak Estimated 200,000 cases of S. enteriditis, attack rate of 6.6% Media age 13 yr, 62% male Premix carried in tanker that had carried non-pasteurized eggs Isolated from 3% of products in plant, not isolated from plant environment or tanker

17 Campylobacter Prevalent on chicken carcasses. C. jejuni causes: 1,000,000 infections / year. 8,500 hospitalizations / year. 76 deaths / year. Estimated prevalence of 2 to 9% in bulk tank milk. 1 in 1,000 cases leads to Guillain-Barre Syndrome: Neurologic condition: mild to severe weakness or paralysis.

18 Campylobacter Greatest risk poultry Freezing decreases bacterial survival Recent outbreaks raw milk in PA, AK Racine County raw milk brought to school

19 Coliforms, fecal coliforms, E. coli, pathogenic E. coli Coliform bacteria: rod-shaped Gram-negative oxidase negative non-spore forming bacteria that ferment lactose with the production of acid and gas at C Fecal Coliforms: same as above plus resistant to bile salts and ferment lactose with the production of acid and gas when incubated at 44 C E. coli: are indole positive fecal coliforms in the gut microflora of all animal species. Pathogenic E. coli cause disease by their ability to attach to or invade cells, or elaborate various toxins

20 Escherichia coli Named for Austrian doctor Theodor von Escherich ( ) EHEC; Enterohemorrhagic E. coli (0157 and others) ETEC; Enterotoxigenic E. coli EPEC; Enteropathogenic E. coli EAEC; Enteroaggregative E. coli UPEC; Uropathogenic E. coli With permission:

21 Human E. coli infections Estimated 176,000 cases STEC (0157 and others), 2400 hospitalizations, 20 deaths Estimated 18,000 cases, ETEC and other types, 12 hospitalizations, no deaths Estimated STEC prevalence of 0 to 4% for bulk tank milk

22 E. coli Diarrhea 5-day-old Holstein calf Watery yellow diarrhea No fever Depressed Lethargic White-yellow, not bloody, no flecks of mucosa.

23 Scanning EM Calf Gut Gyles & Thoen, 2 nd edition, 1993 Normal jejunum Higher magnification Infected with ETEC

24 Attachment & Effacement Gyles & Thoen, 2 nd edition, 1993 Scanning EM E. coli attached to calf gut Transmission EM Microvilli being destroyed

25 Shiga-like toxin (SLT) = Verotoxin Several E. coli serotypes have stx2 gene E. coli O157 most commonly involved in patients. Focus in meat on Big 6 non 0157 serotypes

26 Listeria There are several species in the genus Listeria These are environmental bacteria that have the ability to survive and multiply under a wide array of conditions Nearly all cases of listeriosis are caused by Listeria monocytogenes The latter produces a number of components that allow it to invade and multiply within mammalian cells Isolation of Listeria species is an indicator for the possible presence of L. monocytogenes

27 Food Safety - Listeriosis Estimated 1600 cases, 255 deaths, per year in the U.S., 94% hospitalization rate, 16% death rate Has been declining for decade or more Responsible for 7% of the 3037 estimated foodborne disease deaths in U.S. each year. Legal limit of < 1 CFU per 25 g of readyto-eat meat product ( zero tolerance ) Many recalls - very costly (est. $2.3 billion/yr, ERS/USDA)

28 Listeria as an animal pathogen Environmental soil, water, vegetation Silage can multiply if ph greater than 5.0 Predilection for ruminants

29 Listeria monocytogenes Ruminants circling disease, abortion Intracellular pathogen Very responsive to environment Growth temp. - 4 to 45 C Salt tolerant Bile salt tolerance

30 Listeriosis Food Outbreaks Listeria species- can colonize niche in food plant (e.g. drain, rollers Difficult to eradicate even with proper hygiene Environmental vs. pathogenic strains Almost all outbreaks serotype 4b Sporadic cases all serotypes Estimated prevalence of 3 to 7% in bulk tank milk

31 Risk Factors for Listeriosis Pregnancy (fetus) Increasing age (>65 years) Malignancy (especially hematological) Immunosuppression (e.g. HIV, chemotherapy, anti-tnf, steroids) Reduction in gastric acid Alcoholism Renal or liver disease Can lead to meningitis or meningoencephalitis

32 Past Outbreaks 1981 Nova Scotia 41 cases 18 deaths contaminated coleslaw California 142 cases 48 deaths Mexican style cheese (raw milk)

33 Past Outbreaks multiple states Hot dogs 108 cases 14 deaths 2000 and 2002 multiple states Deli turkey meat 30 cases (2000) 54 (2002) 7 deaths (2000) 8 (2002)

34 Human abortion storms North Carolina Homemade Mexican-style cheese (raw milk) 13 cases - 11 of which perinatal 8 deaths Other maternofetal outbreaks California 1985 Switzerland France 1993

35 2011 Jensen Farms cantaloupe 146 cases, 28 states 142 hospitalized Median age 77 years 30 deaths average age 82 years

36 Staphylococcus aureus Present on the skin of people and animals

37 Staph. aureus Enterotoxins S. aureus causes a food intoxication other agents we discussed mostly food infections S. aureus grows well in high protein foods. Salt resistant Growth and toxin production down to a w of % of Staph aureus strains produce enterotoxin Need approx CFU/g for enterotoxin production Results in release of signals from S. aureus cells that triggers enterotoxin

38 Staph aureus enterotoxins Heat-stable protein Survives moderate cooking temperatures. Resistant to proteolytic enzymes Induces nausea, vomiting, diarrhea. Two bucket disease Superantigen intense inflammation Humans more susceptible to toxin than animals.

39 Old School Food Safety Research I wish you could see the enthusiasm with which the group is taking hold of the work. I happened.. to take 25 cc of filtrate I was surprised to find the violent reaction which could occur so quickly I guess I looked like a ghost. The prostration was very marked and the pulse was so thready.i feel that it is a bit dangerous to carry out human experiments because we might endanger the life of the individual. Gail Dack, MD January 28,1930

40 S. aureus enterotoxemia U.S. Estimated 241,000 foodborne cases/year 1064 hospitalizations 6 deaths Estimated 27 to 41% prevalence of S. aureus in bulk tank milk Organism killed by pasteurization Organism dies off in raw milk cheese; enterotoxin could remain Conditions to prevent growth and toxin production in foods

41 Staphylococcus aureus intoxication reworked milk Japan 14,000 people sick 98 hospitalized Diarrhea Vomiting Associated with drinking low-fat milk Some complained of strange smell in milk Workers at dairy plant recycling products returned by large-lot customers. Cartons were opened manually with bare hands and poured into a storage vat for recycling.

42 FDA Compliance Policy Guide (Sec Dairy Products Dec. 2009) Dairy products may be considered adulterated if Salmonella, Campylobacter, or E. coli 0157 is present, or if S. aureus enterotoxin is present Dairy products may be considered adulterated if S. aureus cells present at 10 4 CFU/g or greater Presence of E. coli in cheese from raw milk at greater than 100 MPN/g indicates insanitary conditions. Same for non-cheese raw milk product with greater than 10 MPN/g. If greater than 10 MPN/g in dairy product from pasteurized milk, indication of post-pasteurization contamination.

43 Acknowledgments Mike Collins Chuck Kaspar Suzanne Gibbons-Burgener

44 For more information contact: Chuck Czuprynski, Director Or Kathy Glass, Associate Director