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Problem based Learning Case ASPH education academic public

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					 CHAPTER 7: SAFE FOODS

Problem-Based Learning Module:
   The Case of Jimmy Culbert

   Undergraduate Education
                                                           TABLE OF CONTENTS

I.    OVERVIEW OF THE CASE .................................................................................................. 3

II. OVERVIEW OF THE LEARNING OBJECTIVES ............................................................... 4

III. OVERVIEW OF THE TWO SESSIONS ................................................................................ 5

IV. FACILITATOR’S GUIDE ...................................................................................................... 6

V. HANDOUT 1 ........................................................................................................................ 11

VI. HANDOUT 2 ........................................................................................................................ 12




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I.     OVERVIEW OF THE CASE

During the first session, the students will be presented with the case of Jimmy Culbert, a young boy who is
taken to a local pediatric emergency room with severe diarrhea and dehydration. He is admitted to the hospital
and diagnosed with Salmonella infection. He responds well to supportive treatment and antibiotics and is able
to return home after several days.

A cluster of similar cases turn out to be due to the same Salmonella infection (as determined by DNA-
fingerprinting methodology). Epidemiological investigation by the local public health department traces the
infections to several restaurants in the area that all received shipments of eggs from the same local distributor.
Health department inspection of the restaurants, the egg distributor, and the original producer identifies a
number of inadequate processes in the chain of production, distribution, storage, and preparation of the eggs.




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II.   OVERVIEW OF THE LEARNING OBJECTIVES

      A.   Identify common biological agents frequently implicated in food-borne illness outbreaks.

      B.   Explain the current epidemiology of Salmonella infections in the United States.

      C.   Explain the process by which bacteria can be “fingerprinted” using modern genetic testing
           methods.

      D.   Identify the various authorities responsible for the investigation of food-borne illnesses and how
           they can implement improved food safety processes.

      E.   Describe safe preparation and handling techniques for food at home, in restaurants, and food
           processors/distributors.




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III.   OVERVIEW OF THE TWO SESSIONS

SESSION 1:

At the beginning of session 1, you should divide the class into small groups of 6-8 students. One student in each
group should be identified as the group facilitator for the case (alternatively, you may have teaching assistants or
other faculty serving as group facilitators). That student should be given the “Facilitator’s Guide” and enough
copies of the two handouts for each member of the group. The facilitator will identify one group member, a
“scribe,” to track progress in covering the learning objectives before distributing Handout 1 (describing Jimmy
Culbert’s presentation at a local pediatric emergency facility and his subsequent hospital course). The group
should begin the process of reviewing the learning objectives and related questions. After initial discussion of
the case, students should be given Handout 2 that describes the investigation that leads to the identification of
local restaurants implicated in the outbreak and their common source of eggs. The students may be assigned
additional research on the topic to take place prior to the next session.

SESSION 2:

Session 2 will be used to complete the discussion of learning objectives from session 1. There are two options
for the management of this session:

A. Students can meet again in their small groups and discuss the results of their research amongst themselves.
The group facilitator ensures that all objectives are reviewed and that information is accurate. The instructor
can then ask if any of the groups have residual questions about which they remain uncertain.

B. The instructor can lead the entire class in a discussion by collecting responses to the learning objectives from
each group facilitator and identifying students to review their research with the class as a whole. The instructor
ensures that all objectives are reviewed and that information is accurate.




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IV.    FACILITATOR’S GUIDE

As the group facilitator, you will have a detailed overview of the learning objectives, suggested lines of inquiry
to lead the group, and background information on the case and the learning objectives. Your role is not to tell
the students the answers, but to facilitate their ability to identify the key issues in the case. The questions under
each learning objective form the basis for student research between this class session and the next class session
when responses to the questions will be presented and reviewed. Appropriate comprehension of the answers to
the questions enable the facilitator to assure the learners have achieved the learning objectives for the PBL
module.

SESSION 1: MANAGING THE DISCUSSION

TO DO: Have the group assign a "scribe" to keep track of the discussion and the learning objectives as they are
covered. Distribute Handout 1 and initiate discussion of the case, identifying issues and learning objectives, per
below. After exploring the case, distribute Handout 2 and review the investigation and results.

1.     Opening the Discussion

The first step in dealing with this case should be one of problem identification, that is, what problems do the
students perceive as relevant to the situation? A suggested opening line of inquiry follows: “How did this
happen and what could have been done to prevent it?”

2.     Investigating Learning Objectives

       A. Identify common biological agents frequently implicated in food-borne illness outbreaks.

               How did Jimmy acquire this infection?

               What other infections are acquired in this way?

       B. Explain the current epidemiology of Salmonella infections in the United States.

               How common are Salmonella infections in the United States and how do individuals get infected
               with this bacterium?

       C. Explain the process by which bacteria can be “fingerprinted” using modern genetic testing methods.

              How are bacteria tested to determine whether or not similar cases are related to one another?
       D. Identify the various authorities responsible for the investigation of food-borne illnesses and how
       they can implement improved food safety processes.

               What kind of investigation is undertaken when a possible outbreak of food-borne disease is
               suspected?

               Who undertakes such an investigation?


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       E. Describe safe preparation and handling techniques for food at home, in restaurants, and food
       processors/distributors.

               What sorts of factors in the chain of food preparation and handling may lead to contamination of
               food?

BACKGROUND INFORMATION REGARDING THE LEARNING OBJECTIVES

Salmonellosis is an enteric bacterial infection caused by one of numerous strains of Salmonella. Salmonella is
acquired by ingestion of small quantities of living Salmonella bacteria, usually from contaminated food. The
most commonly contaminated foods include animal products such as meat, milk, poultry, and eggs. However,
other foods can be contaminated with Salmonella as well, particularly if raw animal products are not carefully
separated from other foods, or the same kitchen utensils are used for both without careful cleaning. Some
people can be “carriers” of salmonella bacteria and can contaminate foods if they do not carefully wash their
hands before handling food products. Salmonella is killed by adequate cooking of food products. Salmonella is
also harbored by most reptiles including snakes and turtles. Infection can occur after handling such animals.

Salmonellosis is a diarrheal illness with an incubation period of 12-72 hours after ingestion. Infected
individuals usually develop systemic symptoms such as fever, headache, and fatigue, along with vomiting (less
common), diarrhea, and abdominal cramping. The illness usually lasts 4-7 days and is self-limited in the
majority of patients, meaning that it gets better without specific treatment. Treatment for more severe infections
where dehydration develops may include intravenous fluids. Generally, treatment with anti-diarrheal drugs or
antibiotics is discouraged in most patients. In some cases, particularly in very young children or adults with
other diseases (such as HIV infection), the disease can be more severe. Treatment with antibiotics, as well as
intravenous fluids and support, may be necessary. Many Salmonella strains have developed extensive anti-
microbial resistance patterns (commonly resistant to as many as four antibiotics and sometimes resistant to as
many as seven) requiring careful laboratory testing to ascertain an appropriate antibiotic treatment regimen.

There are a variety of other food-borne infections that are similar to Salmonella and need to be distinguished by
appropriate cultures or other laboratory tests. These include other bacteria or their toxins including Shigella,
Campylobacter, Yersinia, Vibrio Cholera, Clostridia, toxigenic E. Coli such as O157:H7, and Listeria. Other
non-bacterial pathogens such as Cryptosporidium or Cyclospora can also cause food-borne illnesses.

Because of the high incidence of viral gastroenteritis in adults and children, it can be difficult to distinguish
individuals with food-borne infections from those with viral infections. Factors that suggest a food-borne
illness include high fever, severe abdominal pain, prolonged diarrhea (more than 3 days), bloody diarrhea, and
severe weight loss and dehydration. In these cases, appropriate stool testing should be done to isolate potential
food-borne pathogens.

When Salmonella species are isolated from stool testing, they should be reported to the local public health
authorities. Per the Centers for Disease Control and Prevention (CDC): “Although disease reporting is
mandated by legislation or regulation at the state and local levels, state reporting to CDC is voluntary. Reporting
completeness of notifiable diseases is highly variable.” The Public Health Laboratory Information System
(PHLIS) is the public health laboratory-based, national surveillance system for Salmonella, Shigella,


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Campylobacter, and Shiga toxin-producing E. coli isolates. The Salmonella annual reports can be found at
http://www.cdc.gov/ncidod/dbmd/phlisdata/salmonella.htm.

In the case of Salmonella, the National Salmonella Surveillance System collects reports of isolates from states
via PHLIS, which are then forwarded to Enteric Diseases Epidemiology Branch of the Division of Foodborne,
Waterborne, and Environmental Diseases at the National Center for Emerging and Zoonotic Infectious Diseases
of the CDC. Genetic and biochemical testing of Salmonella Species is undertaken via the PulseNet system that
links to state and regional public health agencies. The combination of serotyping and subtyping undertaken by
PulseNet allows detailed “fingerprinting” of Salmonella species. CDC officials use this data to identify possible
clusters of infection that may be linked to common source outbreaks.

Over the past 10 years, the reported incidence of Salmonella infections has declined about 10%. A number of
agencies together regulate the safety of food products and preparation in efforts to decrease Salmonella
infection. The Food and Drug Administration (FDA) and the United States Department of Agriculture (USDA)
regulate the safety of the food supply through inspections, food safety regulations, and food testing. The USDA
manages meat, poultry, and processed egg products, while the FDA manages all non-meat products. At the
local level, food safety is usually managed by state, county, or city health departments that regulate the food
preparation industry, conduct local inspections, and report diseases through to the national agencies.

Salmonella is a ubiquitous organism that contaminates most animal feces and poultry products. It can easily
contaminate meat, poultry, and eggs or egg products at various stages in the slaughter or packaging of such
products at the original producer or at distributors. Contaminated products can cause disease if they are not
properly handled and cooked either at restaurants or in the home. In addition, failure to avoid contamination of
other foods or food preparation surfaces after handling contaminated meat, poultry, or eggs can lead to
contamination of non-meat/animal products with Salmonella.




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Resources
   1. Centers for Disease Control and Prevention. Bacterial Foodborne and Diarrheal Disease National Case
       Surveillance. Annual Report, 2005. Atlanta: U.S. Department of Health and Human Services, Centers
       for Disease Control and Prevention; 2007.
   2. Centers for Disease Control and Prevention. Diagnosis and Management of Foodborne Illnesses: A
       Primer for Physicians and Other Health Care Professionals. MMWR. 2004;53(RR04):1-33.
   3. Centers for Disease Control and Prevention. (2010). National Center for Zoonotic, Vector-Borne, and
       Enteric Diseases: Division of Foodborne, Bacterial and Mycotic Diseases. Retrieved from
       http://www.cdc.gov/nczved/dfbmd.
   4. Centers for Disease Control and Prevention. (2010). National Center for Zoonotic, Vector-Borne, and
       Enteric Diseases: Division of Foodborne, Bacterial and Mycotic Diseases: Salmonellosis. Retrieved
       from http://www.cdc.gov/nczved/divisions/dfbmd/diseases/salmonellosis/.
   5. Centers for Disease Control and Prevention. (2010). OutbreakNet Team: Data and surveillance.
       Retrieved from http://www.cdc.gov/outbreaknet/surveillance_data.html.
   6. Centers for Disease Control and Prevention. (2010). OutbreakNet Team: Outbreak Retrieved from
       http://www.cdc.gov/outbreaknet/outbreaks.html.
   7. Centers for Disease Control and Prevention. (2010). OutbreakNet Team. Retrieved from
       http://www.cdc.gov/foodborneoutbreaks/reporting_professionals.htm.
   8. Centers for Disease Control and Prevention. (2010). PHLIS Surveillance Data Salmonella Annual
       Summaries: Annual Summary, 2005. Atlanta, Georgia: US Department of Health and Human Services,
       CDC, 2007. Retrieved from http://www.cdc.gov/ncidod/dbmd/phlisdata/salmonella.htm.
   9. Centers for Disease Control and Prevention.). Preliminary FoodNet Data on the Incidence of Infection
       with Pathogens Transmitted Commonly Through Food—10 States, 2006. MMWR. 2007;56(14):336-
       339.
   10. Centers for Disease Control and Prevention. (2010). Public Health Laboratory Information System
       (PHLIS). Retrieved from http://www.cdc.gov/ncidod/dbmd/phlisdata/default.htm.
   11. Centers for Disease Control and Prevention. (n.d.). Salmonella. Retrieved from
       http://www.cdc.gov/salmonella.
   12. FoodSafety.gov web site. (2010). Retrieved from http://www.foodsafety.gov.
   13. Trust for America's Health. (2008). Fixing Food Safety: Protecting America's Food Supply from Farm-
       to-Fork. Retrieved from http://www.healthyamericans.org/reports/foodsafety08.
   14. United States Department of Agriculture. (2010). U.S. Safety and Inspection Service (FSIS).Retrieved
       from http://www.fsis.usda.gov.
   15. U.S. Food and Drug Administration. (2010). Food. Retrieved from
       http://www.fda.gov/Food/default.htm.




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SESSION 2: MANAGING THE DISCUSSION

TO DO: Summarize the learning objectives identified at the last session and agree on an order for addressing
them, then appoint a new scribe to keep track of the discussion and new or unresolved questions that arise.
Next, identify students to discuss their research findings related to the learning objectives, and facilitate
discussion among the group.




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V.     HANDOUT 1

Jimmy Culbert is a four-year-old boy previously in good health. He was brought to the pediatric emergency
room late one evening. His parents report that he developed a low grade fever 2 days ago, which was followed
by severe watery diarrhea as frequently as every 1-2 hours for the past 24 hours. He was complaining of a
headache and abdominal pain. He had not vomited, but he had a poor appetite and had not been able to drink
very much during this time. His temperature during the day had risen to 102.3º by oral thermometer. His
parents have given him some acetaminophen for his fever and attempted to push liquids aggressively. No one
else in the home has been ill.

Jimmy has no other medical illnesses. He takes no medications and has no known allergies. He has never been
hospitalized. He has a normal development milestone history. He attends a daycare program at a local church
three full days per week. He is an only child.

Emergency Room Evaluation

Jimmy was evaluated in the Emergency Department. He was found to have fever. He was dehydrated and
required intravenous fluids. His white blood cell count was elevated, suggesting a bacterial infection. Jimmy
was admitted to the hospital for continued intravenous fluids and further evaluation and treatment.




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VI.    HANDOUT 2

Jimmy was given intravenous fluids and an antibiotic call ciprofloxacin by mouth. On his second hospital day,
cultures of his stool grew out Salmonella enteriditis that was resistant to the ciprofloxacin. He was changed to
another antibiotic. He improved over the next two days and was sent home on oral antibiotics.

Several other patients were admitted to the hospital after Jimmy with similar symptoms. They also were found
to be infected with Salmonella. Investigation showed that it was the same subspecies that infected Jimmy. The
cases were all reported to the local health department, which investigated the outbreak. It was determined that
Jimmy and others ate egg products at a local restaurant chain. Salmonella was isolated from some of the eggs at
one of the restaurants. All restaurants in the chain received eggs from a single distributor. Multiple potential
inadequacies in the chain of food preparation, storage, shipping, and production were identified in the outbreak
investigation.




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