A. Initial Public Health Response
Active and enhanced passive surveillance were performed to determine the extent of the outbreak. A news release was issued by the Cumberland County Health Department on May 14th. All NC local health departments were notified through the NC Health Alert Network (www.nchan.org) on May 14th, and an Epi-X notification to all US state health departments was released on May 15th. CCHD established a call line to provide a description of the outbreak to the public and collect information about possible cases. CCHD and NC DPH staff established daily conference calls to coordinate public health response and communication. Since several of the initial cases were food workers, CCHD Environmental Health staff immediately organized a training session on food safety for all employees to reinforce elements of the Food Code. Food employees are defined as “an individual working with unpackaged food, food equipment or utensils, or food-contact surfaces” according to the 2009 FDA Food Code, adopted by reference in the Rules Governing the Food Protection and Sanitation of Food Establishments (15A NCAC 18A 2600).
B. Case Finding and Hypothesis
A case was defined as: A person presenting with onset of nausea, vomiting, abdominal cramps and/or diarrhea, within three days of food or beverage consumption at the Holiday Inn Bordeaux and Conference Center on or after 1 May 2013 OR (secondary case) a person who developed these symptoms after being in close contact with a case as defined above.
- Confirmed Case: A clinically compatible case with laboratory confirmed salmonellosis matching PFGE outbreak strain
- Probable Case: A clinically compatible case with no positive laboratory result but epidemiologically linked to the outbreak
- Exclusion Criteria: A clinically compatible case with Salmonella culture of a PFGE pattern different from the outbreak strain
C. Clinical Laboratory Investigation
Stool specimens were requested of all case-patients. Stool culture, Salmonella serotyping and PFGE analysis were conducted on each specimen. Stool cultures were performed at the North Carolina State Laboratory of Public Health (NC SLPH), and the state laboratories in South Carolina and Louisiana where some cases were residents. Serotyping and PFGE were performed at state laboratories of public health. All testing was accomplished in accordance with standard protocol (http://www.cdc.gov/pulsenet/PDF/ecoli-shigella-Salmonella-pfge-protocol-508c.pdf).
D. Environmental Investigation
Four environmental health staff from Cumberland County Health Department began an on-site investigation upon notification of a possible foodborne outbreak on May 13, 2013. The Holiday Inn Bordeaux has a first floor and a second floor kitchen. The first floor kitchen services the All American Grill, a sports bar restaurant serving American food from 5pm – 11pm daily. The first floor kitchen also services the Café Bordeaux breakfast buffet. The second floor kitchen services banquet events and the Café Bordeaux lunch buffet. Salads for the lunch buffet are stored in the first floor kitchen. During the investigation, CCHD environmental health staff was accompanied by the Holiday Inn Bordeaux kitchen manager and the assistant general manager. Food sources, storage, and preparation were assessed. Food, refrigerator, freezer, and water temperatures were monitored. Hand washing stations and supplies were inspected. Food products were not sampled. Subsequent to the initial site visit, multiple repeat visits were made to the facility during the course of the investigation to ensure compliance with outbreak control measures (see Environmental Results below). On May 28, 2013, the North Carolina Department of Agriculture collected twenty environmental samples from various components of a faulty dishwasher that was being stored in the facility basement after being disconnected due to improper water temperatures.
E. Results
Case Patients
One hundred case-patients were identified: 25 confirmed; and 75 probable. Twenty-nine (29%) of the 100 case-patients were staff and 71 (71%) were patrons of the hotel and/or hotel restaurants. One staff person likely became ill as a result of secondary transmission. Of the 29 ill staff, ten (35%) were laboratory confirmed with the outbreak strain, one (3%) tested negative, one (3%) had a final result of unsatisfactory, and 17 (59%) did not submit a stool specimen. Of the 71 patrons, 15 (21%) tested positive for the outbreak strain, 26 (37%) tested negative, one (1%) had a final result of unsatisfactory, and 29 (41%) did not submit a stool specimen. Of the 75 probable cases, 27 persons tested negative for Salmonella, 46 persons did not submit a stool specimen, and two had unsatisfactory samples as a final result.
Illness onset dates for the 100 case-patients ranged from May 1, 2013, to May 17, 2013 (Figure 1 – Epidemiologic Curve). The majority of case-patients were residents of North Carolina (87%); 4/100 (4%) were from Maryland, 2/100 (2%) South Carolina, 2/100 (2%) Alabama, and 1/100 (1%) from Colorado, Illinois, Louisiana, New Jersey, and New York, respectively. All case-patients reported an association with the Holiday Inn Bordeaux. Fifty-seven percent were female.
Laboratory Results
Among 54 people who had specimens submitted for testing, 25 (46%) were positive by culture, 27 (50%) were negative, and two (4%) had a final result of unsatisfactory. Of the 25 positive results, 100% grew Salmonella species on stool culture. Of these, 25/25 (100%) were serotype Typhimurium and 25/25 (100%) were a PFGE match to pattern JPXX01.0038. While this pattern is seen each year in North Carolina, it is not a common pattern. The historical incidence rate for this pattern of Salmonella Typhimurium in North Carolina is <0.5 to 2% per year.
The onset dates of persons testing positive for this outbreak strain ranged from May 2, 2013, to May 16, 2013.
North Carolina’s State Laboratory of Public Health is part of a national surveillance system, PulseNet, which is a database of PFGE patterns for all Salmonella specimens submitted to state laboratories across the US. Other than the previously identified epidemiologically linked patients, there were no reports of the outbreak strain from other state laboratories across the country during the time period of this outbreak.
Environmental Results
Site visits to the Holiday Inn Bordeaux were conducted daily from May 13 through May 24. Interviews with managerial staff and observation of food preparation identified multiple opportunities for Salmonella contamination, including improper water temperatures and the absence of hand washing supplies in some areas. Other potential food safety issues that were identified included bare hand contact with ready to eat foods, temperature violations, and a dishwasher in one kitchen that was not operating effectively as described by staff members. Food Code requirements that were reinforced and control measures recommended by environmental health included exclusion of ill employees, elimination of bare hand contact with ready to eat foods, consistent logging of food temperatures, and discontinued use of the faulty dishwasher.
The following points were noted during the first environmental health inspection:
- A fan obstructing access to the hand wash sink near the dish washing machine.
- This same sink was out of paper towels.
- Although the minimum temperature for a hand wash sink is 100˚F, the temperature reading from the water leaving the faucet for this sink was 75˚F.
- Soap dispensers were empty in the hand wash sink near the kitchen toaster area and in the female bathroom at the Café Bordeaux entrance.
- The booster for the hot water sanitizing dish washing machine was not in compliance with the minimum temperature of 140˚F as required by the manufacturer’s data plate. The temperature was reading 124.4˚F. The booster was being used despite the fact that it had not been functioning properly for the prior three weeks. Staff had been instructed to run the dishes through the dish washing machine twice since it was not reaching the proper temperature. In addition, thermo labels indicated that the surface temperature of dishes did not reach 160˚F, as required by the Food Code. Environmental health staff instructed the kitchen staff to discontinue this practice and use the 3 compartment sink or use a chemical rinse after running dishes through the dish washing machine.
Conclusions
An outbreak of Salmonella Typhimurium gastroenteritis occurred in North Carolina during May 2013. One hundred cases were identified and included residents of North Carolina, Alabama, Colorado, Illinois, Louisiana, Maryland, New Jersey, New York, and South Carolina. All isolates available for PFGE analysis had identical patterns (JPXX01.0038), representing an uncommon but recurring pattern in the national PulseNet database and for the state. The source of the outbreak was the All American Grill within the Holiday Inn Bordeaux. However, a specific food item could not be implicated during the investigation. One likely reason a specific food item was not identified, as the vehicle in this outbreak was cross-contamination of food products or surfaces in the restaurant. Although sanitizing solutions were tested by inspectors and found to be in compliance, inadequate dish machine temperatures and hand washing could contribute to the cross-contamination. Furthermore, during the course of this investigation, it was revealed that seven food service employees, as defined by the North Carolina Food Code Manual, continued to work while ill. Hotel management was notified that food service employees should be excluded from work until they are asymptomatic for at least 24 hours.
Failure to adhere to guidance requiring exclusion of ill food handlers may have played a role in facilitating ongoing contamination in the facility.
Salmonella Typhimurium with the pattern JPXX01.0038 was found to be the cause of this outbreak, and likely caused illness through a variety of mechanisms, including consumption or handling of undercooked food (due to lack of temperature log), consumption of cross contaminated ready to eat foods, and/or contact with contaminated surfaces.
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