An outbreak of Salmonella muenchen infection in a specialist paediatric hospital

A nosocomial outbreak of Salmonella enteritidis associated with lyophilized enteral nutrition

Outbreaks of Salmonella spp. gastro-enteritis in hospitals are of concern because of the increased susceptibility of patients and associated high morbidity. This study is a report of a nosocomial outbreak of Salmonella enteritidis associated with enteral nutrition. In December 1999, one sample of enteral feed tested positive for S. enteritidis. During the subsequent 6 weeks, eight cases of nosocomial salmonellosis occurred. Patients involved in the outbreak were aged 19-79 years (median = 36.5), and salmonella was isolated from the blood of two patients. All patients were receiving enteral nutrition at the time and all had diarrhoea. Three patients died. All 13 employees of the Nutrition Department were asymptomatic and their stool samples were negative. Environmental and water samples were also negative. The diet, however, contained lyophilized egg albumin. Molecular typing showed that the isolates of seven patients were indistinguishable from the one obtained from the enteral diet. It was thought that the nosocomial salmonellosis probably occurred due to the use of a commercial lyophilized diet. Another method of processing diets may be necessary to ensure patient safety.

Outbreaks of salmonellosis in hospitals in England and Wales: 1992-1994

Data from the surveillance scheme of general outbreaks of infectious intestinal disease in England and Wales were used to describe the epidemiology of outbreaks of salmonellosis in hospitals from 1992-1994. Outbreaks of infectious intestinal disease in hospitals accounted for 15% (189/1275) of all outbreaks. A salmonella was the implicated pathogen in 12% (22/189). The mode of transmission was described as mainly person to person in 12 outbreaks, mainly foodborne in eight and equal or unknown proportions of foodborne and person to person in two. The most common strain involved was Salmonella enteritidis PT4 (11 outbreaks). The mean duration of outbreaks was 16 days. The mean attack rate in patients was 25% but varied from 2-67%. Illness was reported in 260 patients, of whom 130 had a laboratory confirmed infection. Eight hundred and twenty-six asymptomatic patients were tested, 31 of whom were positive. The salmonella infection was believed to have contributed to the deaths of five patients. Ill staff (115) were tested and 68 were positive; 1508 well staff were tested and 33 were positive. Outbreaks of salmonellosis in hospitals are preventable. Attack rates can be high and outbreaks are often prolonged, with high morbidity and associated disruption of hospital services. There is need for effective infection control policies, appropriate training of staff, simple surveillance systems and readily available expert advice to ensure outbreaks are rapidly controlled.

Use of ciprofloxacin to control a Salmonella outbreak in a long-stay psychiatric hospital

An outbreak of diarrhoea due to Salmonella virchow phage type 8 occurred in a major block of a large psychiatric hospital. The two other major blocks of the hospital remained unaffected. No source of infection was identified and the epidemiological investigations pointed to cross-infection as the mode of transmission. Infection control measures were implemented at an early stage but a total of 55 patients and four members of staff were affected. The disease was self-limiting and of short duration. During the course of the outbreak, Salmonella typhimurium phage type 66 also emerged as a pathogen and was isolated from the stools of symptomatic cases with diarrhoea. Owing to the size of the hospital, the lack of facilities for infection control, the nature of the patients' illnesses and an increasing number of affected patients, it was decided to treat all symptomatic and asymptomatic patients with oral ciprofloxacin 500 mg twice daily for 7 days. A quantitative stool culture for salmonellae was undertaken on days 3, 7, 10, 30, 60 and 90 from the start of treatment. All patients' and staff's stool cultures became negative on day 7 and remained negative for a period of 6 months during follow-up. We conclude that cross-infection outbreaks due to Salmonella spp. in psychiatric and geriatric hospitals can be controlled by isolation in a designated ward and supportive therapy, together with ciprofloxacin treatment.

Food-borne disease in hospitals: prevention in a changing food service environment

The results of an investigation into an outbreak of food-borne disease at a hospital in Los Angeles County are reported. The outbreak occurred at a luncheon buffet for nonpatient visitors attending an event at the hospital, which was catered by the hospital. The food source and etiologic agent(s) responsible for the outbreak were not identified by our investigation. However, several issues relating to the changing character of hospital food provision and their implications for prevention of food-borne disease in hospitals were conspicuous. Two trends apparent in hospital food service are toward increased use of foodstuffs prepared by wholesale food manufacturers and more frequent invitation to community groups to meet within hospital facilities and use hospital catering services. We found that (1) hospital kitchens in Los Angeles County are undersurveyed with respect to frequency of sanitary inspections; (2) hospitals have no mechanism whereby to assess the sanitary inspection record of wholesale food manufacturers from whom they purchase foodstuffs; and (3) crossover of food items prepared for nonpatient hospital visitors, including catered foods, to the inpatient menu occurs. The potential risks for a food-borne disease outbreak among compromised inpatients resulting from these factors are discussed, and measures to reduce such risk are proposed.

An outbreak of Salmonella typhimurium gastroenteritis in a psychiatric hospital

An outbreak of Salmonella typhimurium (phage type 12) infection involving 11 patients and 12 members of staff occurred in a psychiatric hospital in Merseyside during a 3-week period in September and October 1984. Bacteraemia did not occur in any patients, those affected having a mild self-limiting diarrhoea. The source of the organism remained unknown but the most probable means of transmission was by person to person contact. The outbreak was controlled by transferring affected patients to an isolation ward. Staff were encouraged to report gastrointestinal symptoms and remain off work until symptom free or until the results of cultures were known. The problems of managing the outbreak are discussed.

Investigation of outbreaks of salmonella in hospitals

In a two year prospective survey of outbreaks of salmonella infection in hospitals in England and Wales 55 outbreaks were identified. Reports of investigation of these outbreaks were reviewed for evidence of food borne infection and cross infection. Food borne infection probably accounted for only six outbreaks, but these made up 40% of the 15 outbreaks in which there were more than five patients and staff with symptoms. Person to person transmission was the probable mode of spread in most outbreaks. It is recommended that in addition to bacteriological investigations clinical and epidemiological data should be collected to implicate food or other possible common vehicles of infection. Bacteriological screening of patients and staff who do not have symptoms may be unrewarding in the absence of epidemiological data to define groups at risk of infection.