Multistate Outbreak of Multidrug-Resistant Salmonella I 4,[5],12:i:- and Salmonella Infantis Infections Linked to Pork (Final Update)
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Posted December 2, 2015 1:30 PM ET
This outbreak appears to be over. However, Salmonella is an important cause of human illness in the United States. For more information about Salmonella and steps that people can take to reduce their risk of infection, visit CDC’s Salmonella webpage.
Highlights
- Read the Recall & Advice to Consumers, Restaurants, and Retailers »
- This outbreak appears to be over. However, Salmonella is an important cause of human illness in the United States. For more information about Salmonella and steps that people can take to reduce their risk of infection, visit CDC’s Salmonella webpage.
- Epidemiologic, laboratory, and traceback findings identified pork produced by Kapowsin Meats as the likely source of this outbreak of Salmonella I 4,[5],12:i:- and Salmonella Infantis infections.
- 192 people infected with the outbreak strains of Salmonella I 4,[5],12:i:- (188) and Salmonella Infantis (4) were reported from five states.
- Most ill people were reported from Washington.
- 30 ill people were hospitalized, and no deaths were reported.
- CDC’s National Antimicrobial Resistance Monitoring System (NARMS) laboratory conducted antibiotic-resistance testing on clinical isolates collected from 10 ill people infected with one of the outbreak strains of Salmonella I 4,[5],12:i:-.
- All 10 isolates (100%) were multidrug resistant. This included resistance to ampicillin, streptomycin, sulfisoxazole, and tetracycline.
- Antibiotic resistance may be associated with increased risk of hospitalization, development of a bloodstream infection, or treatment failure in patients.
- On August 27, 2015, Kapowsin Meats issued an expanded recall of approximately 523,380 pounds of pork products that might be contaminated with Salmonella I 4,[5],12:i:-.
- Consumers should check their homes and freezers for the recalled pork products and should not cook or eat them. Retailers should not sell these products and restaurants should not serve them.
Outbreak Summary
Introduction
The Washington State Department of Health (DOH), Public Health—Seattle & King County (PHSKC), several states, CDC, and the U.S. Department of Agriculture’s Food Safety and Inspection Service (USDA-FSIS) investigated an outbreak of Salmonella I 4,[5],12:i:- and Salmonella Infantis infections linked to pork.
Public health investigators used the PulseNet system to identify illnesses that may be part of this outbreak. CDC coordinates PulseNet, the national subtyping network of public health and food regulatory agency laboratories. DNA “fingerprinting” is performed on Salmonella bacteria isolated from ill people using techniques called pulsed-field gel electrophoresis (PFGE) and whole genome sequencing (WGS). WGS gives a more detailed DNA fingerprint than PFGE. PulseNet manages a national database of these DNA fingerprints to identify possible outbreaks of enteric illness. Six DNA fingerprints (outbreak strains) were included in this outbreak investigation. The six strains are rare in Washington but more common in other U.S. states. WGS was performed on clinical isolates from ill people in other states who were suspected to be part of the outbreak. Some of these isolates were found to be closely genetically related to clinical isolates from Washington. This close association provided additional evidence that illnesses that occurred in other states were related to the illnesses in Washington.
A total of 192 ill people infected with the outbreak strains of Salmonella I 4,[5],12:i:- (188) and Salmonella Infantis (4) were reported from five states. The number of ill people reported from each state was as follows: Alaska (1), California (2), Idaho (2), Oregon (3), and Washington (184). Most of the ill people infected in states other than Washington traveled to Washington in the week before their illness started.
Among people for whom information was available, illnesses started on dates ranging from April 25, 2015, to September 25, 2015. Ill people ranged in age from less than 1 year to 90, with a median age of 35. Fifty-one percent of ill people were female. Among 180 ill people with available information, 30 (17%) were hospitalized, and no deaths were reported.
Investigation of the Outbreak
Epidemiologic, laboratory, and traceback findings identified pork produced by Kapowsin Meats as the likely source of this outbreak of Salmonella I 4,[5],12:i:- and Salmonella Infantis infections.
In interviews, ill people answered questions about foods eaten and other exposures in the week before they became ill. Of 123 people for whom information was available, 94 (76%) reported eating pork in the week before becoming ill. This proportion was significantly higher than results from a survey [PDF – 29 pages] of healthy people in which 43% reported eating pork in the week before they were interviewed.
In addition, numerous ill people were identified as part of illness clusters following events such as pig roasts. An illness cluster is defined as two or more people who do not live in the same household who report eating at the same restaurant location, attending a common event, or shopping at the same location of a grocery store in the week before becoming ill. Investigating illness clusters can provide critical clues about the source of an outbreak. If several unrelated ill persons ate or shopped at the same location of a restaurant or store within several days of each other, it suggests that the contaminated food item was served or sold there.
Laboratory testing confirmed the outbreak strains in environmental samples collected by Washington State DOH from the Kapowsin Meats facility. On August 13, 2015, Kapowsin Meats voluntarily recalled approximately 116,262 pounds of whole pigs that might be contaminated with Salmonella I 4,[5],12:i:-. The product was shipped to individuals, retail locations, institutions, and distributors in Alaska, Oregon, and Washington.
While Kapowsin Meats took steps to address sanitary conditions at their facility after the original recall on August 13, 2015, USDA-FSIS conducted intensified sampling. The intensified sampling identified Salmonella I 4,[5],12:i:- and Salmonella Infantis on whole pigs for barbeque, on associated pork products, and throughout the facility. Kapowsin Meats voluntarily suspended operations and on August 27, 2015, expanded its recall to include approximately 523,380 pounds of pork products that might be contaminated with Salmonella I 4,[5],12:i:-. Recalled pork products included whole pigs for barbeque, various pork offal products, pork blood, and pork trim. The products were shipped to individuals, retail locations, institutions, and distributors in Alaska, Oregon, and Washington. A review of the PulseNet database identified 4 people infected with the same DNA fingerprint of Salmonella Infantis, and these ill people were included in the outbreak case count. Interviews were conducted with 3 of the 4 ill people; all 3 people reported eating pork in the week before their illness started.
The National Antimicrobial Resistance Monitoring System (NARMS) is a U.S. public health surveillance system that tracks antibiotic resistance in foodborne and other enteric bacteria found in people, raw meat and poultry, and food-producing animals. NARMS is a partnership among the CDC, the U.S. Food and Drug Administration (FDA), USDA, and state and local health departments.
The NARMS human surveillance program at CDC monitors antibiotic resistance in Salmonella and other bacteria isolated from clinical specimens submitted to NARMS by public health laboratories. CDC’s NARMS laboratory conducted antibiotic resistance testing on clinical isolates collected from 10 ill people infected with one of the outbreak strains of Salmonella I 4,[5],12:i:-. Of the 10 isolates tested, all (100%) were multidrug resistant. This included resistance to ampicillin, streptomycin, sulfisoxazole, and tetracycline. Antibiotic resistance may be associated with increased risk of hospitalization, development of a bloodstream infection, or treatment failure in patients.
December 2, 2015
Final Case Count Update
Since the last update on August 28, 2015, 40 more ill people were reported, including 32 people from Washington and 8 people from Alaska (1), California (2), Idaho (2), and Oregon (3).
A total of 192 ill people infected with the outbreak strains of Salmonella I 4,[5],12:i:- (188) and Salmonella Infantis (4) were reported from five states. The number of ill people reported from each state was as follows: Alaska (1), California (2), Idaho (2), Oregon (3), and Washington (184).
Among people for whom information was available, illnesses started on dates ranging from April 25, 2015, to September 25, 2015. Ill people ranged in age from less than 1 year to 90, with a median age of 35. Fifty-one percent of ill people were female. Among 180 ill people with available information, 30 (17%) were hospitalized, and no deaths were reported.
August 28, 2015
Case Count Update
As of August 27, 2015, 152 ill people infected with the outbreak strains of Salmonella I 4,[5],12:i:- have been reported from Washington. Since the last update on August 14, 18 more ill people have been reported.
Among people for whom information is available, illnesses started on dates ranging from April 25, 2015 to August 12, 2015. Ill people range in age from 1 to 90 years, with a median age of 35. Forty-seven percent of ill people are female. Among 144 ill people with available information, 24 (17%) report being hospitalized. No deaths have been reported.
Illnesses that occurred after August 13, 2015 might not be reported yet due to the time it takes between when a person becomes ill and when the illness is reported. This takes an average of 2 to 4 weeks. Please see the Timeline for Reporting Cases of Salmonella Infection for more details.
Investigation Update
Epidemiologic, laboratory, and traceback findings identified pork produced by Kapowsin Meats as a likely source of this outbreak of Salmonella I 4,[5],12:i:- infections. This investigation is ongoing.
In ongoing interviews, ill people answered questions about foods eaten and other exposures in the week before they became ill. Of 89 people for whom information is available, 65 (73%) reported eating pork in the week before becoming ill. This proportion was significantly higher than results from a survey of healthy people in which 43% reported eating pork in the week before they were interviewed.
USDA-FSIS has been conducting intensified sampling at Kapowsin Meats while this establishment took steps to address sanitary conditions at their facility after the original recall on August 13, 2015. Sampling revealed positive results for Salmonella I 4,[5],12:i:- on whole pigs for barbeque, associated pork products, and throughout the establishment. Kapowsin Meats has voluntarily suspended operations. As a result of the ongoing investigation, on August 27, 2015, Kapowsin Meats issued an expanded recall of approximately 523,380 pounds of pork products that may be contaminated with Salmonella I 4,[5],12:i:-. Recalled pork products include whole pigs for barbeque and fabricated pork products including various pork offal products, pork blood, and pork trim. The products subject to recall bear the establishment number “Est. 1628” inside the USDA mark of inspection and were produced on several dates between April 18, 2015 and August 26, 2015. The products were shipped to various individuals, retail locations, institutions, and distributors in Alaska, Oregon, and Washington.
CDC’s NARMS laboratory conducted antibiotic resistance testing on clinical isolates collected from 10 ill people infected with one of the outbreak strains. Of the 10 isolates tested, all (100%) were multidrug resistant. This included resistance to ampicillin, streptomycin, sulfisoxazole, and tetracycline. Antibiotic resistance may be associated with increased risk of hospitalization, development of a bloodstream infection, or treatment failure in patients. CDC’s NARMS laboratory continues to test additional isolates. Results will be reported when they become available.
CDC and state and local public health partners are continuing laboratory surveillance through PulseNet to identify additional ill people and to interview them. Updates will be provided when more information is available.
Initial Announcement
August 14, 2015
The Washington State Department of Health (DOH) and Public Health—Seattle & King County (SKC), with CDC and the U.S. Department of Agriculture’s Food Safety and Inspection Service (USDA-FSIS), are investigating an outbreak of Salmonella I 4,[5],12:i:- infections linked to pork.
Public health investigators are using the PulseNet system to identify illnesses that may be part of this outbreak. PulseNet, the national subtyping network of public health and food regulatory agency laboratories, is coordinated by CDC. DNA “fingerprinting” is performed on Salmonella bacteria isolated from ill people by using a technique called pulsed-field gel electrophoresis, or PFGE. PulseNet manages a national database of these DNA “fingerprints” to identify possible outbreaks. Five DNA “fingerprints” (outbreak strains) are included in this outbreak investigation. The five strains are rare in Washington.
A total of 134 ill people infected with the outbreak strains of Salmonella I 4,[5],12:i:- have been reported from Washington.
Among people for whom information is available, illnesses started on dates ranging from April 25, 2015 to August 1, 2015. Ill people range in age from 1 year to 90, with a median age of 35. Forty-six percent of ill people are female. Among 111 ill people with available information, 16 (14%) report being hospitalized. No deaths have been reported.
This outbreak can be illustrated with a chart showing the number of people who became ill each day. This chart is called an epidemic curve or epi curve. Illnesses that occurred after July 27, 2015 might not be reported yet due to the time it takes between when a person becomes ill and when the illness is reported. This takes an average of 2 to 4 weeks. Please see the Timeline for Reporting Cases of Salmonella Infection for more details.
Investigation of the Outbreak
CDC is assisting DOH and SKC with the epidemiologic investigation. A CDC Epi-Aid team arrived in Seattle, Washington on August 3, 2015.
Epidemiologic, laboratory, and traceback findings identified pork produced by Kapowsin Meats as a likely source of this outbreak of Salmonella I 4,[5],12:i:- infections. This investigation is ongoing.
In ongoing interviews, ill people answered questions about foods eaten and other exposures in the week before they became ill. Of 55 people for whom information is available, 37 (67%) reported eating pork in the week before becoming ill. This proportion was significantly higher than results from a survey [PDF – 29 pages] of healthy people in which 43% reported eating pork in the week before they were interviewed. In addition, numerous ill people were identified as part of illness clusters following events such as whole hog roasts. An illness cluster is defined as two or more people who do not live in the same household who report eating at the same restaurant location, attending a common event, or shopping at the same location of a grocery store in the week before becoming ill. Investigating illness clusters can provide critical clues about the source of an outbreak. If several unrelated ill persons ate or shopped at the same location of a restaurant or store within several days of each other, it suggests that the contaminated food item was served or sold there.
On July 31, 2015, USDA-FSIS issued a public health alert due to concerns about illnesses caused by Salmonella I 4,[5],12:i:- that may be associated with pork products, specifically whole pigs used for roasts. USDA-FSIS advises all consumers to safely prepare raw meat products and only consume pork products that have been cooked to an internal temperature of 145°F with 3 minutes of rest time.
Laboratory testing of environmental samples collected from Kapowsin Meats by DOH confirmed the outbreak strain was present in the facility. The business, which is regulated by USDA-FSIS, has cooperated with the investigation.
As a result of this investigation, on August 13, 2015, Kapowsin Meats voluntarily recalled approximately 116,262 pounds of whole pigs that may be contaminated with Salmonella I 4,[5],12:i:-. The product subject to recall bears the establishment number “est. 1628” inside the USDA mark of inspection and was produced on various dates between April 18, 2015 and July 27, 2015. The product was shipped to various individuals, retail locations, institutions, and distributors in Alaska and Washington.
The National Antimicrobial Resistance Monitoring System (NARMS) is a U.S. public health surveillance system that tracks antibiotic resistance in foodborne and other enteric bacteria found in people, raw meat and poultry, and food-producing animals. NARMS is a partnership among the CDC, the U.S. Food and Drug Administration (FDA), USDA, and state and local health departments.
The NARMS human surveillance program at CDC monitors antibiotic resistance in Salmonella and other bacteria isolated from clinical specimens submitted to NARMS by public health laboratories. CDC’s NARMS laboratory conducted antibiotic resistance testing on clinical isolates collected from three ill people infected with one of the outbreak strains. Of the three isolates tested, all (100%) were multidrug resistant. This included resistance to ampicillin, streptomycin, sulfisoxazole, and tetracycline. Antibiotic resistance may be associated with increased risk of hospitalization, development of a bloodstream infection, or treatment failure in patients. CDC’s NARMS laboratory continues to conduct antibiotic resistance testing on additional clinical isolates collected from ill persons infected with the outbreak strains. Results will be reported when they become available.
CDC and state and local public health partners are continuing laboratory surveillance through PulseNet to identify additional ill people and to interview them. Updates will be provided when more information is available.