Analysis of the impact of a new electro-chemical activation system for potable water disinfection on the Legionella pneumophila isolation rate in a Spanish hospital

Abstract

In a field study comparing isolation rates pre- and post-installation of an electro-chemical activation system for Legionella pneumophila disinfection of potable hot water in a Spanish hospital, a total of 250 tap samples pre-installation and 113 post-installation were collected. Chlorine levels were higher (p < 0.001) post-installation (0.55 ± 0.41 vs. 1.19 ± 0.44 ppm). Of 38.0% (138/363) samples positive for L. pneumophila, 111 (80.4%) were serogroups 2—14. Post-installation, the isolation rate was lower (46.8% vs. 18.6%; p < 0.001, odds ratio (OR) 0.26, 95% confidence interval (CI) 0.15—0.44) due to significant (p < 0.001; OR 0.25, 95% CI 0.14—0.45) reduction in L. pneumophila serogroups 2—14 from 38.4% to 13.3%. Post-installation, isolation rates were lower in spring (44.4% vs. 0.0%; p < 0.001), summer (80.0% vs. 25.0%; p = 0.003) and autumn (72.0% vs. 28.9%; p = 0.018), but not in winter (18.5% vs. 11.8%; p = 0.688). The seasonal wave constructed with pre-installation data significantly decreased post-installation by decreasing isolation rates in summer and autumn to rates similar to those found in winter pre-installation.

Keywords

Electro-chemical activation system hospital potable water supply Legionella water disinfection

Get full access to this article

View all access options for this article.

References

F ranzin L. , Cabodi D. , Bonfrate N. , Tortorelli F. , Bernini L. , Giorgione N. ( 2008) Evaluation of two disinfection systems for Legionella eradication from a hospital water supply. Abstracts of the 23rd European Working Group for Legionella Infections, 11-13 May 2008, Madrid, Spain, Abstract P8.03.

Hosein IK , Hill DW , Tan TY , Butchart EG , Wilson K. , Finlay G. , Burge S. , Ribeiro CD ( 2005) Point-of-care controls for nosocomial legionellosis combined with chlorine dioxide potable water decontamination: a two-year survey at a Welsh teaching hospital. Journal of Hospital Infection 61: 100-6.

Johnson JT , Yu VL , Best MG , Vickers RM , Goetz A. , Wagner R. , Wicker H. , Woo A. ( 1985) Nosocomial legionellosis in surgical patients with head-and-neck cancer: implications for epidemiological reservoir and mode of transmission . Lancet 2: 298-300.

Katz SM , Hammel JM ( 1987) The effect of drying, heat, and pH on the survival of Legionella pneumophila. Annals of Clinical and Laboratory Science 17: 150-6.

Kool JL , Bergmire-Sweat D. , Butler JC , Brown EW , Peabody DJ , Massi DS , Carpenter JC , Pruckler JM , Benson RF , Fields BS ( 1999) Hospital characteristics associated with colonization of water systems by Legionella and risk of nosocomial legionnaires' disease: a cohort study of 15 hospitals Infection Control and Hospital Epidemiology 20:798-805.

Mouchtouri V. , Velonakis E. , Tsakalof A. , Kapoula C. , Goutziana G. , Vatopoulos A. , Kremastinou J. , Hadjichristodoulou C. ( 2007) Risk factors for contamination of hotel water distribution systems by Legionella species. Applied and Environmental Microbiology 73: 1489-92.

O’Neill E. , Humphreys H. ( 2005) Surveillance of hospital water and primary prevention of nosocomial legionellosis: what is the evidence? Journal of Hospital Infection 59: 273-9.

Rivera JM , Aguilar L. , Granizo JJ , Vos-Arenilla A. , Giménez MJ , Aguiar JM , Prieto J. ( 2007) Isolation of Legionella species/serogroups from water cooling systems compared with potable water systems in Spanish healthcare facilities. Journal of Hospital Infection 67: 360-6.

Rivera JM , Granizo JJ , Aguilar L. , Giménez MJ , Aguiar JM , Prieto J.

(2009) Is there a relationship between monthly rainfall and Legionella isolation in potable water systems in Spanish health-care facilities?

Infection Control and Hospital Epidemiology 30: 306-8.

10.

Sabrià M. , Mòdol JM , Garcia-Nuñez M. , Reynaga E. , Pedro-Botet ML , Sopena N. , Rey-Joly C. ( 2004) Environmental cultures and hospital-acquired Legionnaires’ disease: a 5-year prospective study in 20 hospitals in Catalonia, Spain. Infection Control and Hospital Epidemiology 25: 1072-6.

11.

Sabrià M. , Yu VL ( 2002) Hospital-acquired legionellosis: solutions for a preventable infection. Lancet Infectious Diseases 2: 368-73.

12.

Stout JE , Yu VL ( 2001) Legionella in the hospital water supply: a plea for decision making based on evidence-based medicine. Infection Control and Hospital Epidemiology 22: 670-2.

13.

Vonberg RP , Eckmanns T. , Bruderek J. , Ruden H. , Gastmeier P. ( 2005) Use of terminal tap water filter systems for prevention of nosocomial legionellosis. Journal of Hospital Infection 60: 159-62.

14.

World Intellectual Property Organization ( 2007) Water disinfecting apparatus and method WO/2007/057940 . See: www.wipo.int/pctdb/en/wo.jsp?WO=2007057940 . (accessed 23 March 2009).