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Nosocomial acquisition of Salmonella enteritidis among healthy adults
Journal
of Hospital
Infection
(1990)
15, 393-397
Letters
to the Editor
Sir,
Nosocomial
acquisition
of
Salmonella adults
enterifidis
among
healthy
The incidence of salmonella infections has seemingly increased in recent years in European countries. From 1982-1987 notifiable cases have doubled in the UK (Editorial, 19SS), and have tripled in Denmark in the same period-perhaps as a consequence of insufficiently processed and preserved food (Scheibel, 1989). Hospitalized patients appear to be unusually susceptible to salmonellosis (Baine et al., 1973). Person-to-person spread has previously been reported in nosocomial as a possible-perhaps even a characteristic-route salmonellosis among patients (Steere et al., 1975). However, healthy adults are believed to require a larger infecting dose (lo’-10’ organisms) to produce illness. Person-to-person spread of infection is more likely when small numbers of microorganisms can cause illness and it has previously been demonstrated that outbreaks caused by Salmonella eastbourne in chocolate and Salmonella cubana in carmine dye have resulted from the ingestion of small doses, of the order of lo*-lo3 organisms (Craven et al., 1975; Lang et al., 1967). Clinical evidence for person-to-person spread with S. typhimurium phage type 10 in healthy adults has previously been published (Palmer et al., 1981). We report an outbreak of nosocomial acquisition of Salmonella enteritidis among healthy adults, which had epidemiological features consistent with person-to-person spread. In winter 1986 a 69-year-old single woman (patient 1) was admitted to hospital with S. enteritidis infection. A subsequent survey revealed eight healthy adults in contact with patient 1 (Table I), who showed symptoms of gastroenteritis and from whom S. enteritidis was isolated-among these were five nurses from the hospital staff. The organism was not isolated from any hospital patients and no symptomless excretors were discovered. Patients 1, 3 and 4 were hospitalized, but were all discharged in good health after 10, 11 and 18 days respectively. Three months after their illness patients 1, 3 and 4 were still culture-positive for S. enteritidis; the seven other subjects were not. The primary source of infection in patient 1 was not found. None of the individuals involved in the outbreak had exchanged food articles or had any food source in common, so that a food source, as a cause for the spread of 019.5-6701
~9nmo393
c’, ,990 The Hospml
+os $03 OO.‘l~
393
Infecnon
Socwt>
Letters
394 Table
I. Time
Patient
and person
relationship Relationship
to the Editor
between to patient
Daughter Neighbour Nurse Nurse Nurse Nurse Nurse Grandaughter
patient 1
1 and subsequent
cases in outbreak
Timelapse from illness of patient to illness of subsequent cases
1
34 days 10 days 10 days 13 days 13 days 13 days 13 days 1 month
this infection is unlikely. Family members related to the five nurses were all negative for S. enteritidis. No other hospital staff developed symptoms of gastroenteritis. The outbreak involved only relatively few people over a sustained period of time. The only factor in common was contact with patient 1. These findings are consistent with person-to-person spread of S. enteritidis. References Editorial (1988). Salmonella infection and food hygiene. Lancet 2, 860. Baine, W. B., Gangarosa, E. J. Bennett, J. V. & Barker, W. H. (1973). Institutional salmonellosis. Journal of Infectious Diseases 128, 357-359. Craven, P. C., Mackel, D. C., Baine, W. B., Barker, W. H. & Gangarosa, E. J. (1975). International outbreak of Salmonella eastbourne infection traced to contaminated chocolate. Lancet 1, 788-793. Lang, D. J., Kunz, L. J., Martin, A. R., Schroeder, S. A. & Thomson, L. A. (1967). Carmine as a source of nosocomial salmonellosis. New EnglandJournal of Medicine 276,829-832. Palmer, S. R., Jephcott, A. E., Rowland, A. J. & Sylvester, D. G. H. (1981). Person-to-person spread of Salmonella typhimurium phage type 10 after a common-source outbreak. Lancet 1, 881-884. Scheibel, J. (1989). Too many cases of bacterial gastroenteritis? Ugeskrift for Laeger 151, 751. Steere, A. C., Craven, P. J., Hall, W. J., Leostakis, N., Wells, J. G., Farmer, J. J. & Gangarosa, E. J. (1975). Person-to-person spread of Salmonella typhimurium after a hospital common-source outbreak. Lancet 1, 319-322.
L. A. Msller T. Ravn T. Grodum
Department of Microbiology, Ssnderborg Hospital, 6400 Senderborg, Denmark
of Hospital
Infection
(1990)
15, 393-397
Letters
to the Editor
Sir,
Nosocomial
acquisition
of
Salmonella adults
enterifidis
among
healthy
The incidence of salmonella infections has seemingly increased in recent years in European countries. From 1982-1987 notifiable cases have doubled in the UK (Editorial, 19SS), and have tripled in Denmark in the same period-perhaps as a consequence of insufficiently processed and preserved food (Scheibel, 1989). Hospitalized patients appear to be unusually susceptible to salmonellosis (Baine et al., 1973). Person-to-person spread has previously been reported in nosocomial as a possible-perhaps even a characteristic-route salmonellosis among patients (Steere et al., 1975). However, healthy adults are believed to require a larger infecting dose (lo’-10’ organisms) to produce illness. Person-to-person spread of infection is more likely when small numbers of microorganisms can cause illness and it has previously been demonstrated that outbreaks caused by Salmonella eastbourne in chocolate and Salmonella cubana in carmine dye have resulted from the ingestion of small doses, of the order of lo*-lo3 organisms (Craven et al., 1975; Lang et al., 1967). Clinical evidence for person-to-person spread with S. typhimurium phage type 10 in healthy adults has previously been published (Palmer et al., 1981). We report an outbreak of nosocomial acquisition of Salmonella enteritidis among healthy adults, which had epidemiological features consistent with person-to-person spread. In winter 1986 a 69-year-old single woman (patient 1) was admitted to hospital with S. enteritidis infection. A subsequent survey revealed eight healthy adults in contact with patient 1 (Table I), who showed symptoms of gastroenteritis and from whom S. enteritidis was isolated-among these were five nurses from the hospital staff. The organism was not isolated from any hospital patients and no symptomless excretors were discovered. Patients 1, 3 and 4 were hospitalized, but were all discharged in good health after 10, 11 and 18 days respectively. Three months after their illness patients 1, 3 and 4 were still culture-positive for S. enteritidis; the seven other subjects were not. The primary source of infection in patient 1 was not found. None of the individuals involved in the outbreak had exchanged food articles or had any food source in common, so that a food source, as a cause for the spread of 019.5-6701
~9nmo393
c’, ,990 The Hospml
+os $03 OO.‘l~
393
Infecnon
Socwt>
Letters
394 Table
I. Time
Patient
and person
relationship Relationship
to the Editor
between to patient
Daughter Neighbour Nurse Nurse Nurse Nurse Nurse Grandaughter
patient 1
1 and subsequent
cases in outbreak
Timelapse from illness of patient to illness of subsequent cases
1
34 days 10 days 10 days 13 days 13 days 13 days 13 days 1 month
this infection is unlikely. Family members related to the five nurses were all negative for S. enteritidis. No other hospital staff developed symptoms of gastroenteritis. The outbreak involved only relatively few people over a sustained period of time. The only factor in common was contact with patient 1. These findings are consistent with person-to-person spread of S. enteritidis. References Editorial (1988). Salmonella infection and food hygiene. Lancet 2, 860. Baine, W. B., Gangarosa, E. J. Bennett, J. V. & Barker, W. H. (1973). Institutional salmonellosis. Journal of Infectious Diseases 128, 357-359. Craven, P. C., Mackel, D. C., Baine, W. B., Barker, W. H. & Gangarosa, E. J. (1975). International outbreak of Salmonella eastbourne infection traced to contaminated chocolate. Lancet 1, 788-793. Lang, D. J., Kunz, L. J., Martin, A. R., Schroeder, S. A. & Thomson, L. A. (1967). Carmine as a source of nosocomial salmonellosis. New EnglandJournal of Medicine 276,829-832. Palmer, S. R., Jephcott, A. E., Rowland, A. J. & Sylvester, D. G. H. (1981). Person-to-person spread of Salmonella typhimurium phage type 10 after a common-source outbreak. Lancet 1, 881-884. Scheibel, J. (1989). Too many cases of bacterial gastroenteritis? Ugeskrift for Laeger 151, 751. Steere, A. C., Craven, P. J., Hall, W. J., Leostakis, N., Wells, J. G., Farmer, J. J. & Gangarosa, E. J. (1975). Person-to-person spread of Salmonella typhimurium after a hospital common-source outbreak. Lancet 1, 319-322.
L. A. Msller T. Ravn T. Grodum
Department of Microbiology, Ssnderborg Hospital, 6400 Senderborg, Denmark