J. Modol, L. Mateu, M. García-Núñez, M.
Pedro-Botet, N. Sopena, S. Ragull, C. Rey-Joly, M. Sabria; Hospital
Germans Trias i Pujol, Badalona (Barcelona), SPAIN.
Background: Since 1983 HUGTiP has had an endemic
situation of legionellosis. Hyperchlorination and superheating
have not been effective in eradicating this microorganism from
the water supply or decreasing the number of cases of hospital-acquired
Legionella disease (HALD). In September 1999 a Cu/Ag ionization
system was implemented. However some cases of HALD were still
observed in the following years. In May 2003, the dosification
of the ionization system was increased. The aim of the study was
to evaluate the efficacy of the cupper-silver ionization system
on environmental colonization by Legionella and HALD.
Methods: 1. Periods: Period A: 1/1/1998 to 9/30/1999
(21 months); disinfection methods (DM): superheating and hyperchlorination;
HALD surveillance: medical and microbiology lab reports. Period
B: 10/1/1999 to 5/31/2003 (44 months); DM: Cu/Ag ionization in
hot water system, 0.1-0.2 Cu ppm; HALD surveillance: active daily
surveillance. Period C: 6/1/2003 to 12/31/2004 (19 months). DM:
Cu/Ag ionization in hot water system, 0.3- 0.4 Cu ppm; HALD surveillance:
active daily surveillance. 2. Environmental studies: 407 water
samples from distal points were seeded in selective MWY-BCYE-a
agar. 3. Legionella tests: sputum culture, Legionella urinary
antigen and serology. 4. Cu/Ag measurement: atomic absorption
spectroscopy monthly (copper ions were also tested with a daily
sampling kit provided by the manufacturer).
Results: Period A (3 environmental studies):
51/89 (57.3%) of samples were positive for Legionella. Mean number
of CFU/L: 11,972. HALD: 81 cases. Period B (21 environmental studies):
48/230 (20.9%) of samples were positive. Mean number of CFU/L:
758 CFU/L. HALD: 20 cases (9 esporadic cases and 11 associated
with 2 small outbreaks. In both outbreaks Cu/Ag ion levels were
close to 0 due to technical problems). Period C (3 environmental
studies): 14/88 (15.9%) of samples positive. Mean number of CFU/L:
42,982. HALD: 0 cases.
Conclusions: Cu/Ag ionization of hot water systems
decreased environmental contamination by Legionella and reduced
the number of cases of HALD in a hospital with an endemic situation
of legionellosis. The appearance of cases was usually related
to decreases in ion levels. Increasing ion levels may avoid the
appearance of cases of HALD.