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and stores staff were examined bacteriologically and none was found to
be carrying pathogenic organisms. The cause of this outbreak was not
identified, but ensurance that no food still in use was infected and close
attention to kitchen hygiene no doubt were the deciding factors in
bringing this outbreak to an end.
From a bacteriological point of view it is of interest to note how
long the patients continued to excrete the infecting organism. Of the 17,
5 were free in less than 1 week, 4 were free in less than 2 weeks, 5 in less
than 3 weeks, 1 in less than 4 weeks, 1 in less than 6 weeks, and 1 in less
than 7 weeks. A new born baby who contracted the infection from its
mother continued to excrete salmonella for more than 3 months.
The second hospital outbreak was also due to a salmonella, but of the
type known as Typhimurium which is the commonest variety. On the
11th, 12th and 13th of July not less than 16 adults out of some 350 at
risk were taken ill with diarrhoea and abdominal pain.
Bacteriological investigation of the affected individuals revealed
the causal salmonella, but there were no remnants of the infected food
available. Enquiries into the dietary of each case left no doubt, however,
that the vehicle of infection was a chicken fricassee eaten at the evening
meal of the 10th July. Although the responsible meal only gave rise to
16 notified cases directly, the infection unfortunately was transmitted
to a residential infants' nursery established in the hospital premises
and 3 days later on the 16th July, 31 of these children developed
diarrhoea. S. typhimurium was recovered from 25 of them.
The staff was fed from a separate kitchen and bacteriological
investigation of the staff working in the kitchen and of others who
handled food for the staff or the nursery revealed that 19 were excreting
the Salmonella organism. There was evidence that some had had symptoms,
but all were free of symptoms when the first specimens were taken.
Altogether, including the secondary cases, some 77 individuals suffered
from the infection. The illness lasted from 2 to 5 days and all recovered.
The chicken fricassee received considerable manual manipulation
in the process of preparation. The boiled chickens were cooked one day
and stripped manually the next day when a prepared sauce was added,
and served to the staff 5 hours later. The probability is that the sauce
or the meat was infected by a member of the staff who was either suffering
from or carrying Salmonella typhimurium at the time. It should be
noted that 19 members of the staff, mostly in the kitchen, were found
positive on investigation. Most of these were undoubtedly victims of
the outbreak, but it is probable that one or other of them was infected
before the outbreak. Certainly one of the staff who was engaged on
stripping the chickens was found to be positive after the event and she
may have been so before.
It would seem that the average incubation period, i.e., time from
ingestion to onset of illness, was 27 hours. Sufferers continued to excrete
the causal organism for varying periods. Nearly all were free within
a month, most of them in from 14 to 21 days.
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