WHY TO USE POINT-OF-USE FILTERS IN IMMUNE COMPROMISED UNITS

WHY TO USE POINT-OF-USE FILTERS IN IMMUNE COMPROMISED UNITS

Bone Marrow Transplant / Neonates Intensive Care Unit / Intensive Care Unit / Burn Unit

Patients hospitalized in bone marrow transplantation, NICU and other high risk hospital units have zero immune system due to the treatments used for avoiding the reject of the bone marrow transplantation and other immune suppressing environment factors; thus the necessity to protect these patients from environmental contamination is accepted worldwide. For years, diverse ventilation systems and air treatment processes are dedicated to insure a specific air quality both in the corridors and in the patient’s rooms but the necessity to control the water quality has appeared only more recently.

One of the first papers mentioning the contamination of water for hematological patients has been published a few years after the discovery of Legionella pneumophila by Helms et al in 1983 with a cluster of 24 nosocomial cases of Legionnaire’s disease in an Iowa hospital. Thus appeared the possibility of transplanted patients to be infected with water bacteria. Then were described some patients infected with Gram- bacteria with a hydric tropism like Pseudomonas aeruginosa, able to grow inside biofilms and resistant to numerous biocides and antibiotics. This allows Pseudomonas to colonize water distribution networks, fittings, siphons and every humid environment (surfaces, linen, medical devices, etc…) ; thus this bacterium is a formidable adversary for immunosuppressed patients.

Burkholderia  complex cepacia and Stenotrophomonas maltophilia, were also described as able to infect transplanted patients as they are more are involved  during infections in Intensive Care Units (ICUs) which also houses immunocompromised patients.

The results of the routine analyses of drinking water public networks indicate a low percentage of positive samples for Pseudomonas aeruginosa or Legionella pneumophila at very low concentrations. Thus the hospital networks may be seeded with these bacteria which will find here perfect conditions for their growth, excepting in case of adequate preventive measures.

A first approach for limiting the risk of contamination of transplanted patients in an US hospital seems to have been reported by Matulonis et al. in 1993 for diminishing the incidence rate of Legionella pneumonia among transplanted patients. With the technical solutions available at this time (central filtration, UV treatment, heating and chlorination) they used a combined approach to « decontamination » of water supply in a hematological unit in the Western Pennsylvania Cancer Institute in Pittsburgh. The results were significant with only 3 cases of Legionella pneumonia among 201 patients undergoing transplantation in a new Bone Marrow Transplantation (BMT) unit. In contrast 33 cases (!!) of Legionella health care associated infections were detected from approximately 150 patients treated in general medical floors during the same period.

This underlines the importance of a high water quality during the patient’s grooming in BMT, NICU units or for rinsing all medical devices for these immunosuppressed patients with a very high risk of pneumonia, bacteria and septicemia.

Then appeared the description of the risk to acquire mold infections even the perfect quality of the air. This has been published both for Aspergillus species and Fusarium species by Anaissie et al. (2001 and 2003) The incidence of mold infections in patients with hematologic malignancies continued to increase despite the widespread use of air filtration systems, suggesting the presence of other hospital sources for these molds. In the study published in 2003, molds were recovered in 70% of 398 water samples.

During the same period numerous epidemiological studies have been dedicated to the health care associated infections due to Pseudomonas aeruginosa in ICUs and resuscitation room. An excellent synthesis may be found in the articles of Vincent et al 1995 and Richards et al 1999. This bacterium is the second one in term of infection’s incidence, behind Staphylococcus aureus, with a prevalence of around 30%. The epidemiological situation is quite variable according to the hospitals and their control measures, but it is possible to assume that, globally speaking, half of these infections in ICUs are endogeneous, linked to an original carriage by the patient. The second half of these infections is due to cross-contamination due to a transmission to the patient of a human or environmental strain; in this case the water inside the ICU is often the reservoir of this strain (Bertrand et al. 2001). It is acceptable to think the situation is not very different in BMT units.

Thus it appeared necessary to secure the faucets in these hospital wards for avoiding waterborne infections. It seems that the first team which used Point of Use Filters (PoUFs) in a hematological ward was Italian, with a presentation of Ricci and Vianelli during a congress in 2004.  Trautmann was the first one to publish in 2001 and to demonstrate the efficacy of PoUFs in ICU. In his study the use of filters produced bacteria free water at all points of use and a progressive diminution of the number of colonizations/infections from 5 to 10 at the beginning to 0 or 1 each month at the end of the study. Some researchers pinpointed the lack of statistical power of this study, thus this group, after a longer observation’s period, published in 2008 new results clearly evidencing the efficacy of the PoUFs.

The same demonstration has been published in a hematological ward by Vianelli et al in 2006 after installing filters at all point of use (taps and showers).

Since this initial period, more and more wards in Europe began to use PoUFs for the reduction of the bacterial and fungal content of water used for cares and for being in accordance with the quality criteria requested in the French water guidelines (Guide de l’Eau 2005) for the water called «Bacteriologically Controlled Water» (BCW). Warris at al. pinpointed also in 2010 the excellent results of PoUFs for the retention of fungi.

For BMT units, this is a national standard of care in most of the European countries. The absence of control of water inside the room of an immunosuppressed patient would be considered as a fault in case of healthcare acquired infection and the hospital would be considered as guilty by any expert and court.

The increased surveillance and water quality control in wards hosting patients at both risk and high risk are in the framework of the global step called by WHO « Water Safety Plan ». Its application inside the health care settings is absolutely essential and the terminal filtration of water inside BMT units, where  the most fragile hospitalized patients in term of immune suppression,  is an undisputable progress of the last decades.

 

LITERATURE

ANAISSIE E.J., KUCHAR R.T., REX J.H. et al Fusarioris associated with pathogenic Fusarium species colonization of a hospital water system. A new paradigm for the epidemiology of opportunistic mold infections. Clin. Inf. Dis. 2001;33(12);1871-1878.

ANAISSIE E.J., STRATTON S.L., DIGNANI M.C. et al. Pathogenic molds (including Aspergillus species) in hospital water distribution systems : a 3-year prospective study and clinical implications for patients with hematologic malignancies. Blood. 2003;101;2542-2546.

BERTRAND X., THOUVEREZ M., TALON D. et al. Endemicity, molecular diversity and colonisation routes of Pseudomonas aeruginosa in intensive care units. Intensive Care Med. 2001;27;503-12.

HELMS C.M., MASSANARI R.M., ZEITLER R. et al. Legionnaire’s disease associated with a hospital water system : a cluster of 24 nosocomial cases. Ann. Intern. Med. 1983;99(2);172-178.

MATULONIS U., ROSENFELD C.S. & SHUDDUCK R.K. Prevention of Legionella infections in a bone marrow transplant unit : multifaceted approach to decontamiantion of a water system. Infect. Contr. Hosp. Epidemiol. 1993;14(10);571-575.

RICHARDS M.J., EDWARDS J.R., CULVER D.H. et al. Nosocomial infection in medical intensive care units in the United States. Critical Care Med. 1999;27(5);887-92.

TRAUTMANN M., MICHALSKY T., WIEDECK H.et al. Tap water colonization with Pseudomonas aeruginosa in a surgical intensive care unit (ICU) and relation to Pseudomonas infections of ICU patients. Infect. Control Hosp. Epidemiol. 2001;22(1);49-52.

TRAUTMANN M., HALDER S., HOEGEL J. et al. Point of use water filtration reduces endemic Pseudomonas aeruginosa infections on a surgical intensive care unit. Amer. J. Infect. Control. 2008;36;421-9.

VIANELLI N., GIANNINI M.B., QUARTI C. et al. Resolution of a Pseudomonas aeruginosa outbreak in a hematology unit with the use of disposable sterile water filters. Hematologica.2006;91(7);983-5.

VINCENT J.L., BIHARI D.J., SUTER P.M. et al. The prevalence of nosocomial infection in intensive care units in Europe : results of the European Prevalence study of Infection in Intensive Care (EPIC study). J.A.M.A.1995;27(5);887-92.

WARRIS A., ONKEN P., GAUSTAD P. et al. Point of use filtration method for the prevention of fungal contamination of hospital water. J. Hosp. Inf.2010;26;56-59.

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