Plural infection by Salmonella O7 group that hospital infection was doubted

: In Aug, 2002 (heisei 14), a 74-year-old male inpatient had been complaining of fever and diarrhea. A feces culture test was done and a few colonies were discovered and were suspected to be Salmonella O7 and were later confirmed to be as such. A further investigation and interviewing of patients was undertaken. As a result we suspected an internal infection, and did feces culture tests with 7 out of 15 inpatients who had recently had a stomachache or diarrhea and were able to be tested, and 2 discharged patients. Salmonella O7 was detected by direct fulguration in 4 of them and by enrichment in 2, for a total of 6 out of 9 patients. We considered the source to be food poisoning originating in hospital meals and in adherence to the Food Hygiene Law, turned to the proper authorities, which was the Nagaoka Board of Health, for administrative guidance. To search for the cause of this infection, environmental inspections of the patients' rooms and hospital kitchen were undertaken. Further interviews with the patients were also done but they cleared neither the infection source nor the infection route. Even without a genic test, the biotypes were all the same as 53525040. This was discovered by an Autoscan 4 (DADE BEHRING) and the result gave a strong suspicion of an internal infection. The Nagaoka Board of Health was of the opinion that there was a low possibility of the hospital meals being a source of the infection. The reasons were because the diarrhea did not present at the same time among all the patients, there were a distinct few cases of diarrhea among the hospital meal fed patients, and there were no contamination factors found by their investigation of the staff or the system for preparing the meals. Three patients were given an antimicrobic and the measures for training and educating the staff, maintaining a clean environment and fighting infection were re-examined. The case was brought to its conclusion after about 40 days.