0930 oliver revin hort congress 1-17-20121/19/12 3 foodborne%infecbons%caused%by% salmonella!!...
TRANSCRIPT
1/19/12
1
Foodborne Pathogens
Haley Oliver Assistant Professor
Department of Food Science Purdue University
Foodborne Disease Disease resulBng from the consumpBon of
food contaminated with:
– Pathogenic protozoa – Bacteria – Fungi (yeasts and molds) – Toxins – Pathogenic viruses
2
Types of Microorganisms in foods • Food producBon • Food spoilage • Pathogenic
• Food producBon • Food spoilage • Pathogenic
• Pathogenic
Mold
Fig. 2.1, Ray and Bhunia
Bacteria
www.cdc.gov
Virus
Yeast
3
• Food producBon • Food spoilage • Pathogenic • Pathogenic
• Bacterial pathogens • Food producBon
Protozoa
hOp://en.academic.ru/dic.nsf/enwiki/136995
hOp://www.bio.davidson.edu/Courses/Molbio/MolStudents/spring2003/Keogh/plasmids.html
Bacteriophage
Requirements for Foodborne Disease Occurrence
• Microorganism or toxin (the eBological agent) must contaminate the food
• EBological agent must be present in high enough number to cause an illness (depends on the agent)
• Consumer must be suscepBble to the agent
• Sufficient quanBBes of affected food must be consumed
4
Types of Foodborne Disease
• Intoxica@on – ConsumpBon of toxin that is pre-‐formed in food
• Infec@on-‐ IngesBon of M/O in food that colonize intesBnal tract and cause a negaBve health reacBon
5
Sources of Microorganisms (M/O) in Foods
• M/O are everywhere. – Human/mammalian body: Microbial cells outnumber human cells by 10:1
– Food (e.g.) • Raw milk, pasteurized milk • Raw ground beef • Raw spinach • Peanuts
• So how do M/O get into foods? – “Farm-‐to-‐fork” contaminaBon events
– Natural and external sources of microorganisms
6
1/19/12
2
Food ProducBon: Farm-‐to-‐Fork Where can contamina-on happen?
7
Farm Product Distribu@on
Food Manufacturing Plant
Retail Consumer
Foodborne Pathogens = Transmission and Cross-‐contamina@on Challenges
Wild animals
Food animals
Environment soil, water
Food products meat, produce
Humans
Newest Es@mates of Foodborne Disease • 31 major pathogens caused:
– 9.4 million episodes of foodborne illness – 55,961 hospitalizaBons – 1,351 deaths
• Most (58%) illnesses are caused by norovirus, followed by: – Nontyphoidal Salmonella spp. (11%) – Clostridium perfringens (10%) – Campylobacter spp. (9%)
• Leading causes of death: – Nontyphoidal Salmonella spp. (28%) – Toxoplasma gondii (24%) – Listeria monocytogenes (19%) – Norovirus (11%).
EsBmated annual human health burden of selected known foodborne diseases, United States
Pathogen Illnesses Deaths Case-‐fatality Campylobacter 1,322,137 119 0.1%
Salmonella 1,229,007 452 0.5% E. coli O157:H7 96,534 31 0.5% Listeria (LM) 1662 266 15.9%
Scallan, et al., Emerging Infectious Diseases, 2011
Who is Responsible for Food Safety?
Farm Product Distribu@on
Food Manufacturing Plant
Retail Consumer
FoodNet -‐-‐ Foodborne Diseases Ac@ve Surveillance Network
• Determine the burden of foodborne illness in U.S. • Monitor trends of specific foodborne illness over Bme • IdenBfy specific foods and sehngs causing disease • Disseminate informaBon that can lead to improvements in public health and development of intervenBons to reduce foodborne illnesses
• Laboratory tesBng of samples from paBents for: Campylobacter, Cryptosporidium, Cyclospora, Listeria, Salmonella,
Shiga toxin-‐producing Escherichia coli (STEC) O157 and non-‐O157, Shigella, Vibrio, and Yersinia
1/19/12
3
Foodborne InfecBons caused by Salmonella
Leading cause of foodborne disease-‐
related death in the U.S.
13
• All Salmonella enterica – IntesBnes of mammals, especially poultry
• Food associaBon – Poultry, beef, pork, lamb, raw milk and dairy products, eggs, produce – Presence in meat/poultry products and produce – fecal contaminaBon – Presence in eggs – usually a different story – Produce
• Most common culprits
– S. Typhimurium – poultry/meat, some produce – S. EnteridiBs – eggs – Others – S. Tennesee, S. Dublin, etc….. New outbreaks with produce,
peanut, nuts and some meat/poultry
14
Natural Habitat and Presence of Salmonella in Food
• Salmonellosis • Onset: 8-‐24h aker consumpBon of contaminated food • Dura@on of illness: 2-‐3 days
• Infec@ve dose > 105 cells • Target popula@on: Everyone, but higher in YOPIs • Primary symptoms: GastroenteriBs
– Nausea , VomiBng, abdominal cramping, diarrhea (someBmes bloody), fever
• Secondary symptoms: chills, aches • Mortality rate:
– 0.0078 for nontyphodial serotypes
15
Disease caused by Salmonella Salmonella -‐ Pathogenesis Overview
16
PrevenBon of Salmonellosis
• On farm: Reducing animal carriage of Salmonella – SanitaBon – SubtherapeuBc anBbioBcs, – ProbioBcs, reducBon of stress
• At home:
– Thoroughly cook poultry products – Proper cooling – AVOID CROSS CONTAMINATION
17
Campylobacter • Genus Campylobacter
– 18 species and 6 subspecies
• C. jejuni and C. coli are most common cause of human diarrheal disease worldwide – First recognized in 1979 – 5-‐14% of all
• Gram-‐negaBve, moBle, nonsporulaBng, spiral rod-‐shaped bacterium
• Microaerophilic • Fragile cells
18
1/19/12
4
• Enteric M/O • Skin/feathers
– Presence of Campy: 105 cfu/carcass rinse – EffecBveness of saniBzer or hot-‐water dips:
• Ovarian follicules (15%) • ReproducBve tract (42-‐48%) • Eggs (30%)
19
Natural Habitat of Campylobacter-‐-‐Poultry • Campylobacteriosis
• Onset: 2-‐5 days aker consumpBon of contaminated food
• DuraBon: 1-‐10 days • InfecBve dose: Very low – 500 cells
• Target populaBon: Everyone • Primary symptoms: Abdominal cramps, profuse diarrhea,
nausea, vomiBng and fever – occasional bloody diarrhea
• Secondary symptoms: fever, headache, and chills
• Rarely fatal
20
Disease caused by Campylobacter
Campylobacter – Mechanism of Pathogenesis
21
Flagella
CDT toxins
Inflamma@on, Cell damage, Diarrhea
Campylobacter
Chemotaxis and
mo@lity
Invasion and entrapment inside the vacuole
Loss of absorp@ve microvilli
Fig 25.5, Ray and Bhunia
E. coli • Gram-‐negaBve rod • FacultaBve anaerobe • MoBle • Non-‐sporeforming • Normal inhabitant of intesBnal tract of humans and warm-‐blooded animals and birds
22
E. coli: Pathogens vs Non-‐Pathogens
• Most E. coli are nonpathogenic – Nonpathogenic E. coli may be beneficial in intesBne
• Use of E. coli as indicator microorganism
• E. coli as a model organism – Used to study many cellular processes due to its rapid growth rate and simple nutriBonal requirements
23
Shiga-‐Toxin Producing E. coli STECS
24
• “Emerging” pathogens – Common serovars: O157:H7 – O26, O111, O103, O121, O45 and O145 (i.e., non-‐O157:H7) – Produce Shiga-‐like toxins (Stx)
• Disease symptoms: (Enterohemorrhagic coliBs) – Bloody diarrhea – Some vomiBng – Severe abdominal cramping – Occasional fever – HemolyBc Uremic Syndrom
1/19/12
5
STECs
• InfecBve dose: 10-‐100 cells
• Onset: 3-‐9 d
• DuraBon: 4-‐10 d
• Severity: 1-‐2% mortality rate
• Food industry response: Zero tolerance for O157:H7 • non-‐O157:H7 in ground beef and beef trim March 2012
25
PrevenBon of Foodborne E. coli InfecBon • On-‐farm
– PrevenBon of E.coli contaminaBon of water/soil – PrevenBon/limitaBon of STEC in animals
• Hygiene • SubtherapeuBc anBbioBcs, probioBcs
• Food industry – Processing steps – SanitaBon – RouBne tesBng of products and plant environment
• Food retail/at home – Avoid contaminaBon by human handlers – hygiene – Proper cooking – RefrigeraBon – Avoid cross contaminaBon
26
E. coli O1O4:H4
– May 21 – July 26 2011, Germany, largest documented outbreak – IniBally the outbreak was associated with consumpBon of cucumbers
– Subsequent invesBgaBons: consumpBon of fresh sprouted seeds from a single sprouted seed producer in Germany.
– Contaminated seeds used for the sprout producBon were the most likely source.
– STEC isolates responsible for the outbreaks in France and Germany were found to be indisBnguishable. It was therefore concluded that there was a common source for both outbreaks.
– One consignment (lot) of fenugreek seeds imported from Egypt was the most likely link between the outbreaks
– STEC O104 is a very rare serogroup in humans – A total of 3911 cases were reported to the ECDC and WHO – 773 cases of HUS
27
• Foods – can be a natural contaminant of many foods
– Raw products • Produce • Raw meat • Raw milk/dairy products
– Ready-‐to-‐Eat (RTE) products • Because it is present everywhere in the environment, Listeria contaminates food processing plants.
• Psychrotrophic nature allows it to survive/thrive in cold storage areas, drains, etc
• Deli meat • Soa cheeses • Smoked, refrigerated fish • Refrigerated, cooked shrimp • Hotdogs
28
Listeria monocytogenes in Food
• Target Popula@on – YOPIs • Two types of disease:
– Febrile gastroenteriBs – healthy adults – Listeriosis – YOPIs; serious, systemic disease
• Infec@ve Dose-‐ – YOPIs: 100-‐1000 cells – Healthy adults: 106 – 1010 cells
• Onset: – GastroenteriBs – 1-‐7 days – Listeriosis – A few days to two months
• Dura@on of illness: – GastroenteriBs – 2-‐5 days – Listeriosis
29
Disease caused by Listeria Symptoms of Listeria infecBon • Febrile Gastroenteri@s
– Mild flu-‐like symptoms with fever – Abdominal cramps – Diarrhea – Self-‐limiBng
• Systemic Listeriosis – Primarily affects pregnant women, unborn fetuses, infants, the elderly, immunocompromised individuals or cancer paBents taking high doses of steroids or chemotherapy – Fever, headache – MeningiBs, encephaliBs – Spontaneous aborBon or sBllbirth in pregnant women – EndocardiBs – Liver abcesses
30
1/19/12
6
Successive Steps of Human Listeriosis
31
Lecuit, 2007 Listeria can cross three Bght barriers in the human host
T. gondii and foods
• Source: – Cat feces – Foods: Pork, poultry, muOon
• InacBvaBon in foods: – Proper cooking is effecBve – Microwaving not always effecBve – Freezing <-‐10°C for several days is effecBve
32
Toxoplasma gondii
• Intracellular protozoan parasite
• Infect warm-‐blooded animals and birds
• Complicated life cycle with mulBple hosts (including domesBc cats, food animals and humans)
• In humans – muscle cysts – ComplicaBons in pregnant women
• 60 million carriers in the U.S. • Neglected Infec@on of Poverty (NIP) • 2nd leading cause of foodborne death
33
T. gondii infecBon cycle
34
Disease cause by T. gondii • Toxoplasmosis • Onset: 3-‐20 days • DuraBon: a few weeks • Symptoms
– Flu-‐like: ExhausBon, fever, rash, swollen lymph nodes – Pregnant women – complicaBons, miscarriage – Rare complicaBons: cysts in muscle/nervous Bssue
• Target populaBon: Everyone , but especially YOPIs
• Mortality <1% for healthy adults; up to 30% in YOPIs
35
T. gondii and foods
• Source: – Cat feces – Foods: Pork, poultry, muOon
• InacBvaBon in foods: – Proper cooking is effecBve – Microwaving not always effecBve – Freezing <-‐10°C for several days is effecBve
36