Outbreak of Legionnaires' disease in Glasgow Royal Infirmary: microbiological aspects

SUMMARYAn outbreak of legionellosis associated with a hotel in Sydney, Australia, and the subsequent epidemiological and environmental investigations are described. Four cases of Legionnaires' disease were notified to the Public Health Unit. A cross-sectional study of 184 people who attended a seminar at the hotel was carried out. Serological and questionnaire data were obtained for 152 (83 %) of these. Twenty-eight (18 %) respondents reported symptoms compatible with legionellosis. Thirty-three subjects (22 %) had indirect fluorescent antibody (IFA) titres to Legionella pneumophila serogroup 1 (Lp-1) of 128 or higher. The only site which those with symptoms of legionellosis and IFA titre > 128 were more likely to have visited than controls was the hotel car park (adjusted odds ratio [OR] 14 7, 95 % confidence interval [CI]: 1 8-123 1). Those with symptoms compatible with legionellosis, but whose IFA titres were < 128 were also more likely to have visited the hotel car park (adjusted OR 4-4, 95 % CI: 1 5-12 9). Seroprevalence of Lp-I antibodies was higher in those who attended the seminar than in a population sample of similar age. Findings suggested that the 4 cases represented a small fraction of all those infected, and highlighted difficulties in defining illness caused by Lp-1 and in interpreting serology.

Section: Introductionmentioning

confidence: 99%

Legionellosis linked with a hotel car park – how many were infected?

Bell

Jorm²,

Williamson³

et al. 1996

“…Domestic hotwater systems in large buildings such as hotels and hospitals have been shown to be important sources [14], but at the time of the Gloucester outbreak water cooling towers had been implicated in three outbreaks in England and Wales [15][16][17] and two in Scotland [18,19].…”

Section: Discussionmentioning

confidence: 99%

An outbreak of Legionnaires' disease in Gloucester

Hunt¹,

Cartwright²,

Smith³

et al. 1991

SUMMARYFourteen people living in or near the city of Gloucester fell ill with Legionnaires' disease caused by Legionella pneumophila serogroup (SG) 1 between 27 August and 27 October 1986. Another patient had fallen ill on 30 May. Nine of the 15 were diagnosed retrospectively during a case finding exercise. There were three deaths. Three cases of Pontiac fever were also diagnosed.The source was probably one or more wet cooling towers. Nineteen premises in the city with such towers were identified, and three just outside Gloucester. Samples from 11 of the 22 premises grew Legionella spp.; from nine of these L. pneumophila SG 1 (Pontiac) was isolated. The efficacy of regular addition of biocide in addition to hypochlorite added at the time of disinfection in inhibiting the growth of Legionella spp. was demonstrated.A survey of patients' movements during their likely incubation period showed that there was no single building that all patients had visited, but there were two areas of the city which nearly all had visited or passed through by car. A case-control study demonstrated an association with one of these areas.Cooling towers near both areas may have been sources but the evidence is insufficient to incriminate any single one. The unexpected finding of L. pneumophila SG 1 (Pontiac) in nine towers supports the hypothesis that there may have been multiple sources. Cooling towers may have been contaminated by mains water or by drift from other towers.

“…In a recent survey legionellae were grown from 52 % of cooling towers (2). Cooling towers have been the source of many outbreaks both worldwide (4) and in Britain (5)(6)(7)(8). Good maintenance of cooling towers is associated with a lower frequency of contamination with legionellae (3).…”

Section: Introductionmentioning

confidence: 99%

“…Follo-wing an outbreak of Legionnaires' disease in 1984 in Glasgow (5) the need to know the addresses of premises with cooling towers became clear, and the Environmental Health Department of the Glasgow District Council started a register. In 1985 a nosocomial outbreak in Glasgow was linked to a cooling tower (7). Circumstantial evidence emerged that sporadic cases of Legionnaires' disease in Glasgow might be associated with cooling towers (17).…”

Section: Introductionmentioning

confidence: 99%

Maintenance of cooling towers following two outbreaks of Legionnaires' disease in a city

Bhopal

Barr

1990

SUMMARYThis survey assessed the maintenance of evaporative cooling towers in Glasgow, following two Legionnaires' disease outbreaks. Information was obtained from 76 of 81 premises and a maintenance score was calculated for each of 174 towers. The quality of maintenance was extremely varied (range of maintenance scores, 8-30; mean, 22 (S.D., 5.0); median, 23; maximum possible, 33) and some towers were neglected. Breaches of maintenance principles were mainly structural and organizational, e.g. inadequate drift control, rather than failure to use chemicals. Low maintenance scores were associated with no log book, no guidelines, no change in procedures in last 5 years, solitary cooling towers, and towers on industrial premises. Despite intense publicity the standard of cooling tower maintenance in Glasgow remained a concern. Information campaigns directed at those responsible for cooling-tower maintenance are necessary.