From May 7 to 9, 1997, six bedridden patients fed by nasogastric tube (NGT) at the Hafr Al-Batin Extended Care Unit (ECU) and three patients at the main public hospital (KKGH) developed watery diarrhea and fever. We conducted an investigation to determine the extent of this outbreak, its possible source and other contributing factors.
Methodology
A gastroenteritis case was defined as any patient or staff member at KKGH or ECU who developed diarrhea or had Salmonella isolated from a stool specimen from May 1 through May 10, 1997. We reviewed the medical records of all NGT patients, the microbiology records for all stool cultures and the employee absenteeism records to find cases. We reviewed ill and well NGT patient records for demographic characteristics, times and type of food eaten, underlying disease and medications. We also reviewed food preparation, cooking, blending, distribution and storage. We recorded environmental temperatures at each point. We cultured raw chicken, utensils and patients' stools and vomitus/gastric aspirates.
Results
Nine patients met the case definition. ECU and KKGH attack rates (AR) were 100% and 19%, respectively. All case-patients had fever and diarrhea, 67% had vomiting and 78% had hypotension. Salmonella Group D (non-typhi) was recovered from the stools of two ECU patients and from nasogastric aspirates of two additional ECU patients. All NGT patients had exactly the same food type, timing and handling. The time intervals between symptoms and meals were two hours for lunch, eight hours for breakfast, 17 hours for dinner, and 22 hours for lunch of the previous day. Chicken thawing was done in hot water and the cutting board was an old plastic one. Contamination of cooked food by raw food was possible. ECU and KKGH foods were exposed to temperatures ranging from 10 to 51°C and 33*C respectively for up to five hours.
Conclusion
Time-temperature abuse facilitated this outbreak and led to the higher AR among the ECU patients. Salmonella grown from patients strongly suggests that incorrectly handled chicken from dinner eaten 17 hours earlier was the cause of the outbreak (incubation period 17-67 hours). Food preparation and storage for NGT patients is complex. The possibilities for cross-contamination and time/temperature abuse are great. To prevent these, hazard analysis critical control point (HACCP) evaluations should be activated in all MOH hospitals.