2022 Salmonella Outbreak Linked to Fish – Investigation Details
Posted December 14, 2022
This outbreak is over. Learn what you can do to protect yourself from getting sick from Salmonella.
CDC, public health and regulatory officials in several states, and the U.S. Food and Drug Administration (FDA) investigated a multistate outbreak of Salmonella Litchfield infections.
Epidemiologic, laboratory, and traceback data showed that fresh fish sold to restaurants by Mariscos Bahia, Inc. made people sick.
As of December 14, 2022, this outbreak is over.
Epidemiologic and Traceback Data
A total of 39 people infected with the outbreak strain of Salmonella Litchfield were reported from 4 states (see map).
Illnesses started on dates ranging from June 14, 2022, to October 23, 2022 (see timeline). Sick people ranged in age from 1 to 80 years, with a median age of 33, and 66% were female. Of 32 people with information available, 15 were hospitalized. No deaths were reported.
The true number of sick people in this outbreak is likely much higher than the number reported, and this outbreak may not have been limited to the states with known illnesses. This is because many people recover without medical care and are not tested for Salmonella.
State and local public health officials interviewed people about the foods they ate in the week before they got sick. Of the 18 people interviewed, 13 (72%) reported eating raw fish, sushi, or poke. This percentage was significantly higher than the 7.9% of respondents who reported eating raw fish in the FoodNet Population Survey—a survey that helps estimate how often people eat various foods linked to diarrheal illness. This comparison suggests that people in this outbreak got sick from eating raw fish. Of 12 people who remembered details of their meal, 10 (83%) reported raw salmon. Several sick people in the outbreak were identified as a part of three illness clusters at restaurants. An illness cluster is defined as two or more people who do not live in the same household who report eating food from the same retail location before getting sick. If several unrelated sick people ate food from the same retail location, it suggests that the contaminated food item was served or sold there.
FDA’s investigation traced the source of fresh, raw salmon eaten by sick people in the illness clusters back to Mariscos Bahia, Inc.
Laboratory Data
Public health investigators used the PulseNet system to identify illnesses that were part of this outbreak. CDC PulseNet manages a national database of DNA fingerprints of bacteria that cause foodborne illnesses. DNA fingerprinting is performed on bacteria using a method called whole genome sequencing (WGS).
WGS showed that bacteria from sick people’s samples were closely related genetically. This suggests that people in this outbreak got sick from the same food.
FDA collected an environmental sample that included multiple swabs at Mariscos Bahia, Inc., in Pico Rivera, California. Salmonella was identified from multiple environmental swabs collected at the facility. WGS indicated that Salmonella detected in at least one of the swabs from the facility was the outbreak strain.
WGS analysis of bacteria from 38 people’s samples and 4 environmental samples did not predict resistance to any antibiotics; analysis of bacteria from one person’s sample predicted resistance to ciprofloxacin. Most people with Salmonella illness recover without antibiotics. However, if antibiotics are needed, this resistance is unlikely to affect the choice of antibiotic used to treat most people. Standard antibiotic susceptibility testing by CDC’s National Antimicrobial Resistance Monitoring System (NARMS) laboratory is currently underway.
Public Health Actions
On October 20, 2022, Mariscos Bahia, Inc. voluntarily recalled the following list of fresh (not frozen) fish: fresh salmon fillet, fresh deep skin salmon fillet, fresh salmon portions, Chilean seabass (fillet and portions), halibut (fillet and portions), tuna (fillet and portions), and swordfish (loin, fillet, and wheel). The firm shipped recalled product between June 14, 2022-October 17,2022. Businesses should not sell or serve recalled fish.
Public Health Actions
On October 20, 2022, Mariscos Bahia, Inc. voluntarily recalled the following list of fresh (not frozen) fish: fresh salmon fillet, fresh deep skin salmon fillet, fresh salmon portions, Chilean seabass (fillet and portions), halibut (fillet and portions), tuna (fillet and portions), swordfish (loin, fillet, and wheel). The firm began shipping recalled product on June 14, 2022. Businesses should not sell or serve recalled fish.
CDC, public health and regulatory officials in several states, and the U.S. Food and Drug Administration (FDA) are collecting different types of data to investigate a multistate outbreak of Salmonella Litchfield infections.
Epidemiologic, laboratory, and traceback data show that fresh fish sold to restaurants by Mariscos Bahia, Inc., may be contaminated with Salmonella and may be making people sick.
Epidemiologic and Traceback Data
As of October 19, 2022, a total of 33 people infected with the outbreak strain of Salmonella Litchfield have been reported from 3 states (see map). Illnesses started on dates ranging from June 14, 2022, to September 18, 2022 (see timeline).
Sick people range in age from 1 to 67 years, with a median age of 32, and 59% are female. Of 26 people with information available, 13 have been hospitalized. No deaths have been reported.
The true number of sick people in this outbreak is likely much higher than the number reported, and the outbreak may not be limited to the states with known illnesses. This is because many people recover without medical care and are not tested for Salmonella. In addition, recent illnesses may not yet be reported as it usually takes 3 to 4 weeks to determine if a sick person is part of an outbreak.
State and local public health officials are interviewing people about the foods they ate in the week before they got sick. Of the 16 people interviewed, 12 (75%) reported eating raw fish, sushi, or poke. This percentage was significantly higher than the 7.9% of respondents who reported eating raw fish in the FoodNet Population Survey—a survey that helps estimate how often people eat various foods linked to diarrheal illness. This difference suggests that people in this outbreak got sick from eating raw fish. Of 11 people who remembered details of their meal, 9 (82%) reported raw salmon. Several sick people in the outbreak were identified as a part of three illness clusters at restaurants. An illness cluster is defined as two or more people who do not live in the same household who report eating food from the same retail location before getting sick. If several unrelated sick people ate food from the same retail location, it suggests that the contaminated food item was served or sold there. FDA’s investigation traced the source of fresh, raw salmon eaten by sick people in these illness clusters back to Mariscos Bahia, Inc.
Laboratory Data
Public health investigators are using the PulseNet system to identify illnesses that may be part of this outbreak. CDC PulseNet manages a national database of DNA fingerprints of bacteria that cause foodborne illnesses. DNA fingerprinting is performed on bacteria using a method called whole genome sequencing (WGS).
WGS showed that bacteria from sick people’s samples are closely related genetically. This suggests that people in this outbreak got sick from the same food.
FDA collected an environmental sample that included multiple swabs at Mariscos Bahia, Inc., in Pico Rivera, California. Salmonella was identified from multiple environmental swabs collected at the facility and WGS analysis is ongoing. WGS completed to date indicates that Salmonella detected in at least one of the swabs from the facility is the outbreak strain.
WGS of bacteria from one person’s sample predicted resistance to ciprofloxacin; analysis of bacteria from 32 samples did not predict resistance to any antibiotics. Most people with Salmonella illness recover without antibiotics. However, if antibiotics are needed, this resistance is unlikely to affect the choice of antibiotic used to treat most people. Standard antibiotic susceptibility testing by CDC’s National Antimicrobial Resistance Monitoring System (NARMS) laboratory is currently underway.
Public Health Actions
CDC is advising restaurants not to sell or serve salmon, tuna, Chilean sea bass, swordfish, or halibut received on or after June 14, 2022, from Mariscos Bahia, Inc. The fish was distributed to restaurants fresh, not frozen. Fish distributed from Mariscos Bahia’s locations in Pico Rivera, California, and Phoenix, Arizona, are included.
