Salmonellosis, 2010

During 2010, 695 culture-confirmed cases of Salmonella infection (13.2 per 100,000 population) were reported. This represents an 11% increase from the median annual number of cases reported from 2000 to 2009 (median, 628 cases; range, 576 to 755) (Figure 2). Of the 84 serotypes identified in 2010, 5 serotypes, S. Enteritidis (188), S. Typhimurium (102), S. Newport (50), S. I 4,5,12:I:- (31), and S. Heidelberg (19) accounted for 56% of cases. Salmonella was isolated from stool in 615 (88%), urine in 41 (6%), and blood in 30 (4%) cases. Other specimen sources included wounds, an abscess, gall bladder, and bone. There were 8 cases of S. Typhi infection. Among the 7 S. Typhi cases reached for interview, 4 had travelled internationally (India, Lebanon, Pakistan, and Bangladesh) and 1 was an international student from Bangladesh. There was 1 case of S. Paratyphi B infection with unknown travel history.

Of the 629 cases interviewed about travel history, 82 (13%) traveled internationally during the week prior to their illness onset. Four cases died: a 58-year-old case died of acute renal failure associated with hepatocarcinoma 17 days after Salmonella was isolated from a peritoneal fluid sample; a 1-year-old case died of anoxic brain injuries and cardio-pulmonary arrest secondary to acute methadone toxicity 11 days after Salmonella was isolated from a stool sample; a 12-year-old case died of a stroke associated with an underlying blood condition 19 days after Salmonella was isolated from a blood specimen; and Salmonella was isolated at autopsy from the spleen of an 18-year-old case with sudden death.

Fifty-five cases were part of 14 Salmonella outbreaks identified in 2010. Five outbreaks involved cases in multiple states. Thirteen of the outbreaks involved foodborne transmission. One outbreak involved laboratory-acquired infections. The 14 outbreaks resulted in a median of 4 culture-confirmed cases per outbreak (range, 2 to 6 cases).

In April, 2 cases of S. Typhimurium infection were associated with food consumed at a Hmong funeral, including raw cow’s stomach and pudding with raw egg. A specific vehicle was not implicated.

In May, 4 cases of S. Typhimurium infection were associated with a multi-state outbreak that involved 3 other cases in 3 states. A specific variety of commercially distributed prepackaged salad mix was implicated as the vehicle.

In May, 5 cases of S. Enteritidis infection were part of an outbreak at a Mexican-style restaurant. Chile rellenos were implicated as a vehicle and were likely cross-contaminated from raw shell eggs used during the preparation process.

From May to June, 3 cases of S. Chester infection were part of a multi-state outbreak that resulted in 45 cases in 18 states. A commercially distributed cheesy chicken and rice frozen entrée was implicated as the vehicle. A recall of the implicated product was issued.

In June, 3 cases of S. Enteritidis infection were associated with an outbreak at a Chinese-style buffet restaurant. Several food items were significantly associated with illness, including hard boiled eggs. Sanitation violations at the restaurant indicated that cross-contamination of ready-to-eat foods from raw shell eggs in the kitchen was likely.

In June, 4 cases of S. Muenchen infection were associated with a graduation party catered by an unlicensed caterer. No specific food item was implicated.

From June through July, 5 cases of S. Baildon infection were associated with a multi-state outbreak that resulted in 50 cases in 15 states. Consumption of food from a Mexican-style chain restaurant was implicated as the source of some of the infections. A commercial food product was the likely vehicle, as some of the cases had not eaten at that restaurant chain.

In July, 3 cases of S. Enteritidis infection were part of an outbreak at a small bistro restaurant. Eggs and Hollandaise sauce made with unpasteurized shell eggs were implicated as the vehicles.

In July, 5 cases of S. Enteritidis infection were associated with an outbreak at a Mexican-style restaurant. No specific food item was implicated. The infections were likely caused by cross-contamination of ready-to-eat foods from raw chicken.

In August, 6 cases of S. Newport infection were part of an outbreak in which commercially distributed blueberries were implicated as the vehicle.

In August, 4 cases of S. Infantis infection were associated with a church potluck event where macaroni salad was implicated as the vehicle. Cross-contamination of the salad from raw chicken in the preparer’s kitchen was the likely mechanism of contamination.

In September, 2 cases of S. Enteritidis infection were part of an outbreak at a group home where residents were served multiple egg dishes in the week prior to illness onset. The group home had purchased eggs that were part of a nationwide egg recall and were the likely source of infections.

In September, 4 cases of S. Enteritidis infection were associated with two different wedding receptions catered by the same unlicensed caterer on consecutive days. A specific food item was not implicated for either reception.

From August 2010 to April 2011, 5 cases of S. Typhimurium infection in laboratory workers were associated with an ongoing multi-state outbreak that resulted in 73 cases in 35 states. The outbreak strain of S. Typhimurium is used as a quality control strain in clinical and teaching laboratories. Three of the Minnesota cases occurred in 2010.

The May, June, and July restaurant outbreaks and the September group home outbreak that were associated with shell eggs were part of a larger multi-state outbreak that resulted in an estimated 1,939 cases in multiple states. This outbreak resulted in recalls of over 500 million shell eggs from two Iowa producers.

Updated Monday, 28-Nov-2011 14:10:34 CST