During 2014, 722 culture-confirmed cases of Salmonella infection (13.3 per 100,000 population) were reported. This is similar to the median annual number of cases reported from 2004 to 2013 (median, 706; range, 578 to 810). Of the 69 serotypes identified in 2014, 6 serotypes, S. Enteritidis (211), S. Typhimurium (91), S. I 4,,12:i:-(53), S. Newport (34), S. Infantis (22), and S. Heidelberg (20) accounted for 60% of cases. Salmonella was isolated from stool in 618 (86%), urine in 49 (7%), and blood in 43 (6%) cases. Other specimen sources included cerebrospinal fluid, pleural fluid, abdominal fluid, gallbladder fluid, knee aspirate, tracheostomy tube, tissue, and wound.
One hundred ninety-three (27%) cases were hospitalized. Three culture-confirmed cases of Salmonella infection died in 2014: a 68 year-old case died of “natural causes” 16 days after Salmonella was isolated from a urine specimen; a 51 year-old case died of cardiac arrest, ascites, liver failure, and metastatic pancreatic adenocarcinoma 12 days after Salmonella was isolated from a wound; and, a 60 year-old case died of respiratory failure, end stage renal disease, liver cirrhosis, and encephalopathy 4 months after Salmonella was isolated from abdominal fluid during a continuous hospitalization.
Of the 623 cases asked about travel, 86 (14%) had traveled internationally during the week prior to their illness onset. There were 6 cases of S. Typhi infection in 2014; 3 had traveled to India, 1 to Vietnam and Laos, 1 to China and the Philippines, and 1 did not travel in the 30 days prior to illness onset but had travelled to Kenya shortly before that. There were 3 cases of S. Paratyphi A infection; 1 had traveled to India, 1 to India and the United Arab Emirates, and 1 had unknown travel history.
Sixty-eight cases were part of 14 Salmonella outbreaks identified in 2014, including 3 cases that were part of 2 outbreaks in other states. Seven of the outbreaks involved foodborne transmission, four outbreaks were due to animal contact, and the mode of transmission was not conclusive for three outbreaks. Five of the outbreaks, including the two outbreaks in other states, involved cases in multiple states. The 14 outbreaks resulted in a median of 4 culture-confirmed cases per outbreak (range, 1 to 15 cases).
During January-February, 36 cases of S. Enteritidis infection, including 15 laboratory-confirmed cases, were part of an outbreak at a buffet restaurant. Dinner rolls that were brushed with an artificial butter product after baking were the implicated outbreak vehicle, and the suspected source of contamination was raw chicken that was also brushed with butter product at the restaurant.
In January, S. I 4,,12:i:-was isolated from one Minnesota traveler who was part of an outbreak at a restaurant in Hawaii.
In April, 1 S. Typhimurium case was included in a multi-state outbreak that was associated with frozen feeder rodents purchased at a chain pet store. The Minnesota case’s isolate was indistinguishable from the outbreak strain by PFGE, but the case denied contact with feeder rodents or reptiles.
From May through November, 11 S. Adelaide cases were likely associated with consumption of pork. Ninety-one percent of the cases were Asian or Hispanic, and 64% were <5 years old. Most had purchased the pork at a local ethnic store or a live animal market. Cases in other states, including California, were identified during the same time period, but a common source of pork was not identified.
In June, 6 S. Typhimurium cases were associated with an outbreak in central Minnesota that was likely associated with a graduation party or a chain restaurant, but the vehicle was not determined. Reported onset dates were more consistent with the chain restaurant as the source of illness. All of the cases also shopped at the same grocery store chain, and an unidentified food item from the grocery chain was also a possible vehicle.
In May and June, 2 S. Enteritidis cases were part of an outbreak associated with live feeder mice. The outbreak was identified by whole genome sequencing (WGS); the PFGE patterns of the 2 case isolates were one band different by both enzymes but had no single nucleotide polymorphism (SNP) differences by hqSNP analysis. Feeder mice purchased by both cases were sourced from the same distributor in Illinois.
In June, 2 cases of S. I 4,5,12:i:-infection in Minnesota travelers were part of an outbreak associated with a North Dakota pig roast.
From July through September, 2 S. Infantis cases and 1 S. Hadar case were part of a multi-state outbreak of 363 total cases infected with S. Infantis, S. Hadar, or S. Newport from 43 states and Puerto Rico. Transmission was through contact with live poultry sourced from a single hatchery that had also been implicated in national outbreaks in 2012 and 2013.
In July and August, 7 cases of S. Miami infection were part of an outbreak at two locations of a Mexican-style chain restaurant. The outbreak vehicle was not confirmed, but a small focal contamination event affecting lettuce in the field was the most plausible explanation for the outbreak.
In July, 20 cases of S. Javiana infection, including 4 laboratory-confirmed cases, were associated with cooked, shredded turkey prepared by a meat market for a catered event. In 2012, the meat market had been implicated in a S. Javiana outbreak associated with turkey jerky, and the market ceased processing turkeys after the 2014 outbreak.
From August through October, 4 laboratory-confirmed S. I 4,5,12:i:-cases and 8 additional cases were associated with an outbreak among employees of a turkey hatchery. Handling turkey poults and exposure to an environment contaminated by turkey poults were associated with illness.
In August, 8 cases of S. Enteritidis infection were associated with consumption of frozen commercial Chicken Kiev. WGS allowed rapid differentiation of isolates and focus of the investigation. A press release and recall were issued, and positive products were found at retail and in consumers’ homes.
In August, 2 cases of S. Enteritidis infection were associated with a family reunion. The case isolates also had no SNP differences by WGS. The cases had contact with a live goat at the reunion and consumed potluck-style food. The vehicle and route of transmission were not determined.
In August-September, 2 S. Infantis cases were linked to chickens purchased from a live animal market.
Isolates from the January Hawaii outbreak, June North Dakota outbreak, and August-October turkey hatchery outbreak were all serotype 4,5,12:i:-with PFGE pattern TM918 (CDC pattern designation JPXX01.1314). This pattern has undergone a clonal expansion in the last several years, and has been increasingly identified among sporadic case isolates and outbreaks.
- For up to date information see>> Salmonellosis (Salmonella)
- Full issue>> Annual Summary of Communicable Diseases Reported to the Minnesota Department of Health, 2014