Agents of Foodborne Zoonoses • Illnesses caused by – Campylobacter spp. – Escherichia coli O157:H7 – Salmonella • 80-95% cases from these bacteria estimated to be foodborne; probably of animal origin • FoodNet data (repeat) – PulseNet: Molecular epidemiology • Outbreaks and investigations • Carriage by food animals and food • Risk
60
Embed
Agents of Foodborne Zoonoses Illnesses caused by –Campylobacter spp. –Escherichia coli O157:H7 –Salmonella 80-95% cases from these bacteria estimated to.
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
• 80-95% cases from these bacteria estimated to be foodborne; probably of animal origin
• FoodNet data (repeat)– PulseNet: Molecular epidemiology
• Outbreaks and investigations• Carriage by food animals and food• Risk
Foodborne Diseases Active Surveillance Network (FoodNet)
• Principal foodborne disease component of CDC's Emerging Infections Program
• Active surveillance for foodborne diseases and related epidemiologic studies (PulseNet) to better understand the epidemiology of foodborne diseases in the United States.
• “Active” surveillance system, meaning public health officials frequently contact laboratory directors to find new cases of foodborne diseases and report these cases electronically to CDC.
• ID cases likely to be part of an outbreak• Eliminate sporadic cases (background noise)• Difficult to select appropriate method
– Tenover et al. (1997)
• Salmonella– Bender et al (2001)– McQuiston et al (2004)
• E. coli O157:H7– Samadpour (1995)
• Campylobacter– Manning et al (2003)
Some Methods Used for Typing E. coli O157:H7 Strains
Toxin gene screening Thomas et al., 1996; Ostroff et al., 1989
Plasmid profiling Ostroff et al., 1989; Paros et al., 1993; Meng et al., 1995; Radu et al., 2001
Phage typing Ahmed et al., 1987; Khakhria et al., 1990; Barrett et al., 1994
Antibiotic susceptibility testing Kim et al., 1994; Farina et al., 1996; Radu et al., 2001;
Restriction fragment length polymorphism with phage λ (λ -RFLP)
Paros et al., 1993;Samadpour et al., 1993
Ribotyping Martin et al., 1996; Roberts et al., 2001
Pulsed-field gel electrophoresis (PFGE) Bohm and Karch, 1992;Barrett et al., 1994;Meng et al., 1995;Radu et al., 2001
PCR using randomly amplified polymorphic DNA (RAPD) sequences
Swaminathan and Barrett,1995; Radu et al., 2001
PCR using highly repetitive sequences (rep-PCR)
None specific for E. coli-O157:H7; Johnson and O’Bryan, 2000
Amplified fragment length polymorphism analysis (AFLP)
Iyoda et al., 1999; Zhao et al., 2000
How Does PulseNet Work?
1. PFGE
2. Pattern electronic database at local, state or federal level
3. Uploaded to national database at CDC
4. CDC searches for clusters of patterns
5. Local cluster searches
6. Clusters posted to Listserve.
Changes in Outbreaks
• Food consumption and practices in US have changed during the past 20 years
• Shift from the typical point source, or “church supper” outbreak, which is relatively easy to detect to the more diffuse, widespread outbreaks that occur over many communities with only a few illnesses in each community.
Changes in OutbreaksContinued• Large food producing facilities that disseminate
products throughout the country• Some few outbreaks that some low level
contamination of food products• Products are distributed among many states• Only a few illnesses occur in each community, • New laboratory and statistical tools, such as
PulseNet and the surveillance outbreak detection algorithm (SODA), impact ability to identify and investigate these new types of outbreaks
How does subtyping help in epidemiologic investigations?
• Identifies cases within an outbreak • Distinguishes outbreak cases from concurrent
– Cases may be too widely dispersed to detect– Organism too common to notice small increase– Identifies related cases and separates them from unrelated
ones
• DNA “fingerprinting” methods have greatly increased sensitivity of subtyping
Increases sensitivity of outbreak detection
Rangel, J.M. et al. Emerg. Infect. Dis. 11: 603-609 (2005)
Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep
Pe
rce
nt
Po
sit
ive
Sa
mp
les
0.0
0.5
1.0
1.5
2.0
2.5
3.0
log
CF
U/C
arc
as
s
Prevelance
CFU/carcass
Stern and Pretanik (2006)
Risk Factors
• Mostly exposure to food
• Exposure to animals
Risk Factors S. enterica serotype Enteritidis (FoodNet 02-03)
Marcus et al. (2006)
Friedman et al (2004)
Transfer of Campylobacter
Luber et al. (2006)
E. coli O157:H7 Risk Factors(FoodNet 1999-2000)
Voetsch et al (2006)
Peanut Outbreak – 2008-09
FDA Press ReleaseJanuary 12, 2009
• Salmonella recovered from King Nut peanut butter• Minnesota Dept. Agriculture lab results• Genetic match to national cases• Strain associated with 30 illnesses in MN
– About 500 cases nationwide• Distributed to 7 states• Distributed in MN to:
• Produced by Peanut Corporation of America (PCA), a small, family-owned and operated business. HQ in Lynchberg, VA.
• Plant positive for Salmonella in Blakely, GA. <50 employees• No longer producing any products• Expanded recall to include all peanut butter and peanut
paste produced at this plant since July 1, 2008. • Peanut butter and peanut butter paste was not sold directly
to consumers– Distributed to institutions, food service providers, food manufacturers
and distributors in many states, Canada, Korea, and Haiti. – Peanut butter and peanut paste is commonly used in many products,
including cookies, crackers, cereal, candy, ice cream and others.