The hospital water supply as a source of nosocomial infections: a plea for action

The occurrence and prevention of foodborne disease in vulnerable people

In developed countries, such as the United Kingdom and the United States, between 15% and 20% of the population show greater susceptibility than the general population to foodborne disease. This proportion includes people with primary immunodeficiency, patients treated with radiation or with immunosuppressive drugs for cancer and diseases of the immune system, those with acquired immune-deficiency syndrome and diabetics, people suffering from liver or kidney disease or with excessive iron in the blood, pregnant women, infants, and the elderly. Malnutrition and use of antacids, particularly proton-pump inhibitors, also increase susceptibility. We review the occurrence of infection by foodborne pathogens in these groups of people and measures to prevent infection. The nature and use of low microbial diets to reduce the risk of foodborne disease in immunocompromised patients are very variable. Diets for vulnerable people in care should exclude higher-risk foods, and vulnerable people in the community should receive clear advice about food safety, in particular avoidance of higher-risk foods and substitution of safer, nutritious foods.

Effects of systematic oral care in critically ill patients: a multicenter study

BACKGROUND

No standard oral assessment tools are available for determining frequency of oral care in critical care patients, and the method of providing oral care is controversial.

OBJECTIVES

To examine the effects of a systematic program of oral care on oral assessment scores in critically ill intubated and nonintubated, patients.

METHODS

Clinical data were collected 3 times during critical care admissions before and after institution of a systematic program of oral care in 3 different medical centers. The oral care education program consisted of instruction from a dentist or dental hygienist and a clear procedure outlining systematic oral care. The Beck Oral Assessment Scale and the mucosal-plaque score were used to assess the oral cavity. Data were analyzed by using linear mixed modeling with controls for severity of illness.

RESULTS

Scores on the Beck Scale differed significantly (F = 4.79, P = .01) in the pattern of scores across the 3 days and between the control group (before oral education) and the systematic oral care group. Unlike the control group, the treatment group had decreasing scores on the Beck Scale from day 1 to day 5. The mucosal-plaque score and the Beck Scale scores had strong correlations throughout the study; the highest correlation was on day 5 (r = 0.798, P < .001, n = 43).

CONCLUSIONS

Oral assessment scores improved after nurses implemented a protocol for systematic oral care. Use of the Beck Scale and the mucosal-plaque score could standardize oral assessment and guide nurses in providing oral interventions.

Spread of Pseudomonas fluorescens due to contaminated drinking water in a bone marrow transplant unit

Pseudomonas infections are an important cause of morbidity and mortality in immunocompromised patients. We present here data for the spread of Pseudomonas fluorescens caused by a contaminated drinking water dispenser in a bone marrow transplant unit. Over a 1-month period we observed a sharp increase in the isolation of P. fluorescens from weekly pharyngeal surveillance swabs. Environmental samples were taken from a variety of water sources throughout the unit. These samples were cultured on cetrimide agar medium, and isolates were epidemiologically characterized by antibiotic susceptibility patterns and molecular typing methods. Nine patients became colonized with P. fluorescens, and six out of the nine developed febrile neutropenia. P. fluorescens was cultured after the filtration of 100 ml of drinking water from one of two stand-alone chiller units supplying cooled bottled water to the bone marrow transplant unit. All other environmental samples were negative. There were no further cases of P. fluorescens colonization after the contaminated dispenser was removed. Molecular typing showed that all P. fluorescens isolates were identical by both random amplification of polymorphic DNA PCR and pulsed-field gel electrophoresis. We recommend that such bottled water supplies not be used in high-risk areas or be subject to regular microbiological monitoring.

Microbial biofilm control within the dental clinic: reducing multiple risks

This short review focuses on biofilms in the dental clinic environment. Microbial biofilms are potentially a significant source of cross-contamination and cross-infection in the dental clinic. Biofilms in dental chair unit waterlines (DUWLs), suction hoses and fittings pose the most significant risk as these may come into contact with the patient during treatment. These can be managed effectively by regular disinfection using chemical disinfectants and procedures that have proven efficacy. As dental chair units (DCUs) are classified as medical devices, there is a requirement for DCU manufacturers to provide detailed guidance for their decontamination. Planned routine preventive maintenance of the dental clinic water network and good quality water will considerably minimise infection risks from microorganisms in tap water and has benefits for the operation of other clinic equipment. Regular and effective cleaning and disinfection of taps, sinks and splash-backs will help to minimise reservoirs and disseminators of potentially pathogenic bacteria from these areas.

Detection of Helicobacter pylori in biofilms by real-time PCR

Helicobacter pylori is a cause of peptic ulcer disease and a causative agent of gastric cancer. Currently, a possible waterborne route of transmission or a possible survival in drinking water biofilms is discussed. H. pylori, like many other bacterial strains, has the ability to enter the viable but nonculturable state (vbnc) in case of unfavorable conditions. Therefore it is necessary to develop new analysis tools for vbnc bacteria. We established a fast and reliable method to detect H. pylori in drinking water biofilms by quantitative real-time PCR which makes it redundant to use difficult cultivation methods for nonculturable bacteria. With this method it was possible to identify water biofilms as a niche for H. pylori. The real-time PCR analysis targets the ureA subunit of the Helicobacter pylori urea gene which showed high specificity and sensitivity. The quantitative real-time PCR was used to detect H. pylori in biofilms of different age, unspiked and spiked with predetermined levels of cells. The drinking water biofilms were generated in a silicone-tube model. The DNA-sequences for probe and primers showed no cross-homologies to other related bacteria and it was possible to detect less than 10 genomic units of H. pylori. This novel method is a useful tool for a fast screening of drinking water biofilms for H. pylori. The results suggest that drinking water biofilms may act as a reservoir for H. pylori which raises new concerns about the role of biofilms as vectors for pathogens like Helicobacter pylori.

Preventive efficacy and cost-effectiveness of point-of-use water filtration in a subacute care unit

Infections with Pseudomonas aeruginosa and other waterborne pathogens (WBPs) are major contributors to serious morbidity and mortality in hospitals. We sought to determine whether point-of-use (POU) water filtration might result in decreased risk of infection in the subacute care unit (SACU) of a 208-bed medical center. Our findings indicate that POU water filtration can significantly and cost-effectively reduce colonization of and infection with WBPs, including ventilator-associated pneumonia, in an SACU.

Efficacy of copper-silver ionization in controlling biofilm- and plankton-associated waterborne pathogens

The study was to determine the efficacy of copper-silver ionization against the formation of Pseudomonas aeruginosa, Stenotrophomonas maltophilia, and Acinetobacter baumannii in biofilms and planktonic phases. At concentrations below the EPA limits, ionization has potential to control the three waterborne pathogens, in addition to Legionella, in hospital water systems for nosocomial infection control.

Association between contaminated faucets and colonization or infection by nonfermenting gram-negative bacteria in intensive care units in Taiwan

This study was designed to determine the strength of the association between the isolation of nonfermentative gram-negative bacilli (NFGNB) from tap water faucet aerators and the prevalence of colonization or infection of patients in intensive care units (ICUs). Surveillance cultures were obtained during a 4-month period from 162 faucet aerators located in seven different ICUs. The prevalence of colonization or infection of ICU patients with NFGNB was determined by prospective surveillance during the same period. Fifty four (33%) of the faucet aerators contained NFGNB. Among the 66 NFGNB isolated from faucet aerators, the most frequently encountered ones were Sphingomonas paucimobili (26 isolates), Pseudomonas aeruginosa (14 isolates), Chryseobacterium meningosepticum (13 isolates), Achromobacter xylosoxidans (6 isolates), Burkholderia cepacia (4 isolates), and Stenotrophomonas maltophilia (3 isolates). Acinetobacter baumannii was not recovered. The most common NFGNB isolated from ICU patients were P. aeruginosa and A. baumannii. There was a significant correlation between the overall prevalence of NFGNB in faucet aerators and their prevalence in exposed ICU patients (Spearman r = 0.821, P = 0.02). There was also a significant correlation between the prevalence of C. meningosepticum in faucet aerators and its prevalence among ICU patients (Spearman r = 0.847, P = 0.016). The electrokaryotypes of four clinical isolates of C. meningosepticum were similar to those of faucet isolates. Measures directed at making the water supply safe may prevent infection by C. meningosepticum and other waterborne pathogens.

Potentially pathogenic bacteria in shower water and air of a stem cell transplant unit

Potential pathogens from shower water and aerosolized shower mist (i.e., shower aerosol) have been suggested as an environmental source of infection for immunocompromised patients. To quantify the microbial load in shower water and aerosol samples, we used culture, microscopic, and quantitative PCR methods to investigate four shower stalls in a stem cell transplant unit at Barnes-Jewish Hospital in St. Louis, MO. We also tested membrane-integrated showerheads as a possible mitigation strategy. In addition to quantification, a 16S rRNA gene sequencing survey was used to characterize the abundant bacterial populations within shower water and aerosols. The average total bacterial counts were 2.2 x 10(7) cells/liter in shower water and 3.4 x 10(4) cells/m(3) in shower aerosol, and these counts were reduced to 6.3 x 10(4) cells/liter (99.6% efficiency) and 8.9 x 10(3) cells/m(3) (82.4% efficiency), respectively, after membrane-integrated showerheads were installed. Potentially pathogenic organisms were found in both water and aerosol samples from the conventional showers. Most notable was the presence of Mycobacterium mucogenicum (99.5% identity) in the water and Pseudomonas aeruginosa (99.3% identity) in the aerosol samples. Membrane-integrated showerheads may protect immunocompromised patients from waterborne infections in a stem cell transplant unit because of efficient capture of vast numbers of potentially pathogenic bacteria from hospital water. However, an in-depth epidemiological study is necessary to investigate whether membrane-integrated showerheads reduce hospital-acquired infections. The microbial load in shower aerosols with conventional showerheads was elevated compared to the load in HEPA-filtered background air in the stem cell unit, but it was considerably lower than typical indoor air. Thus, in shower environments without HEPA filtration, the increase in microbial load due to shower water aerosolization would not have been distinguishable from anticipated variations in background levels.

Intestinal obstruction associated with chronic peritonitis caused by Sphingomonas paucimobilis

We describe a very rare case of chronic peritonitis with secondary adhesive intestinal obstruction caused by Sphingomonas paucimobilis in a healthy 28-year-old Chinese man. This bacillus has not been described as a cause of spontaneous peritonitis in healthy people. It was an asymptomatic, generalized, and slow-growing peritonitis causing peritoneal adherens and at the end intestinal occlusion that needed surgical adhesiolysis.

Risk assessment of Pseudomonas aeruginosa in water

P. aeruginosa is part of a large group of free-living bacteria that are ubiquitous in the environment. This organism is often found in natural waters such as lakes and rivers in concentrations of 10/100 mL to >1,000/100 mL. However, it is not often found in drinking water. Usually it is found in 2% of samples, or less, and at concentrations up to 2,300 mL(-1) (Allen and Geldreich 1975) or more often at 3-4 CFU/mL. Its occurrence in drinking water is probably related more to its ability to colonize biofilms in plumbing fixtures (i.e., faucets, showerheads, etc.) than its presence in the distribution system or treated drinking water. P. aeruginosa can survive in deionized or distilled water (van der Jooij et al. 1982; Warburton et al. 1994). Hence, it may be found in low nutrient or oligotrophic environments, as well as in high nutrient environments such as in sewage and in the human body. P. aeruginosa can cause a wide range of infections, and is a leading cause of illness in immunocompromised individuals. In particular, it can be a serious pathogen in hospitals (Dembry et al. 1998). It can cause endocarditis, osteomyelitis, pneumonia, urinary tract infections, gastrointestinal infections, and meningitis, and is a leading cause of septicemia. P. aeruginosa is also a major cause of folliculitis and ear infections acquired by exposure to recreational waters containing the bacterium. In addition, it has been recognized as a serious cause of keratitis, especially in patients wearing contact lenses. P. aeruginosa is also a major pathogen in burn and cystic fibrosis (CF) patients and causes a high mortality rate in both populations (MOlina et al. 1991; Pollack 1995). P. aeruginosa is frequently found in whirlpools and hot tubs, sometimes in 94-100% of those tested at concenrations of <1 to 2,400 CFU/mL. The high concentrations found probably result from the relatively high temperatures of whirlpools, which favor the growth of P. aeruginosa, and the aeration which also enhances its growth. The organism is usually found in whirlpools when the chlorine concentrations are low, but it has been isolated even in the presence of 3.00 ppm residual free chlorine (Price and Ahearn 1988). Many outbreaks of folliculitis and ear infections have been reportedly associated with the use of whirlpools and hot tubs that contain P. aeruginosa (Ratnam et al. 1986). Outbreaks have also been reported from exposure to P. aeruginosa in swimming pools and water slides. Although P. aeruginosa has a reputation for being resistant to disinfection, most studies show that it does not exhibit any marked resistance to the disinfectants used to treat drinking water such as chlorine, chloramines, ozone, or iodine. One author, however, did find it to be slightly more resistant to UV disinfection than most other bacteria (Wolfe 1990). Although much has been written about biofilms in the drinking water industry, very little has been reported regarding the role of P. aeruginosa in biofilms. Tap water appears to be a significant route of transmission in hospitals, from colonization of plumbing fixtures. It is still not clear if the colonization results from the water in the distribution system, or personnel use within the hospital. Infections and colonization can be significantly reduced by placement of filters on the water taps. The oral dose of P. aeruginosa required to establish colonization in a healthy subject is high (George et al. 1989a). During dose-response studies, even when subjects (mice or humans) were colonized via ingestion, there was no evidence of disease. P. aeruginosa administered by the aerosol route at levels of 10(7) cells did cause disease symptoms in mice, and was lethal in aerosolized doses of 10(9) cells. Aerosol dose-response studies have not been undertaken with human subjects. Human health risks associated with exposure to P. aeruginosa via drinking water ingestion were estimated using a four-step risk assessment approach. The risk of colonization from ingesting P. aeruginosa in drinking water is low. The risk is slightly higher if the subject is taking an antibiotic resisted by P. aeruginosa. The fact that individuals on ampicillin are more susceptible to Pseudomonas gastrointestinal infection probably results from suppression of normal intestinal flora, which would allow Pseudomonas to colonize. The process of estimating risk was significantly constrained because of the absence of specific (quantitative) occurrence data for Pseudomonas. Sensitivity analysis shows that the greatest source of variability/uncertainty in the risk assessment is from the density distribution in the exposure rather than the dose-response or water consumption distributions. In summary, two routes appear to carry the greatest health risks from contacting water contaminated with P. aeruginosa (1) skin exposure in hot tubs and (2) lung exposure from inhaling aerosols.

Patients' bath basins as potential sources of infection: a multicenter sampling study

BACKGROUND

Nosocomial infections are a marked burden on the US health care system and are linked to a high number of patient deaths.

OBJECTIVE

To identify and quantify bacteria in patients' bath basins and evaluate the basins as a possible reservoir for bacterial colonization and a risk factor for subsequent hospital-acquired infection.

METHODS

In a prospective study at 3 acute care hospitals, 92 bath basins, including basins from 3 intensive care units, were evaluated. Sterile culture sponges were used to obtain samples from the basins. The culture sponges were sent to an outside laboratory, and qualitative and quantitative microbial tests were conducted and the results reported.

RESULTS

Some form of bacteria grew in 98% of the samples (90 sponges), either by plating or on enrichment (95% confidence interval, 92%-99.7%). The organisms with the highest positive rates of growth on enrichment were enterococci (54%), gram-negative organisms (32%), Staphylococcus aureus (23%), vancomycin-resistant enterococci (13%), methicillin-resistant S aureus (8%), Pseudomonas aeruginosa (5%), Candida albicans (3%), and Escherichia coli (2%). Mean plate counts, in colony-forming units, were 10 187 for gram-negative organisms, 99 for E coli, 30 for P aeruginosa, 86 for S aureus, 207 for enterococci, and 31 for vancomycin-resistant enterococci.

CONCLUSIONS

Bath basins are a reservoir for bacteria and may be a source of transmission of hospital-acquired infections. Increased awareness of bath basins as a possible source of transmission of hospital-acquired infections is needed, particularly for high-risk patients.

Targeting the rpoB gene using nested PCR-restriction fragment length polymorphism for identification of nontuberculous mycobacteria in hospital tap water

Nontuberculous mycobacteria (NTM) are ubiquitous in the environment and can cause nosocomial infections in immunocompromised patients. Recently the presence of NTM in public drinking water and hospital water distribution systems has been reported. Their ability to form biofilms and their resistance to chlorine both contribute to their survival and colonization in water distribution systems. Here we analyzed thirty-two hospital tap water samples that were collected from different locations in three hospitals so as to evaluate the prevalence of NTM species. The water samples were concentrated by membrane filtration and then eluted with sterilized water following sonication. Two-step direct PCR targeting the rpoB gene, restriction fragment length polymorphism (RFLP) using the MspI restriction enzyme, and sequence analysis were performed for identification of NTM to the species level. The sequences of each PCR product were analyzed using BLASTN. Seven samples (7/32, 21.9%) were positive for NTM as determined by nested-PCR. The PCR-RFLP results indicated five different patterns among the seven positive PCR samples. The water-born NTM were identified, including M. peregrinum, M. chelonae (2 cases), M. abscessus, M. gordonae (2 cases), and Mycobacterium sp. JLS. The direct two-step PCR-RFLP method targeting the rpoB gene was effective for the detection and the differentiation of NTM species from hospital tap water.

The study of fungi in drinking water

The occurrence of fungi in drinking water has received increased attention in the last decades, and fungi are now generally accepted as drinking water contaminants. The knowledge about the occurrence and diversity of fungi in water has increased considerably from a low knowledge base. However, the relevance of waterborne fungi for water quality and human health is poorly understood and still conflicting. Scientific reports on effective treatment against fungi in water are also few. This article presents a review of the literature on fungal water studies, including some general results, and considerations of significance, limits, contradictions, precautions, and practical consequences.

Disinfection of Burkholderia cepacia complex from non-touch taps in a neonatal nursery

Burkholderia cepacia complex (Bcc) comprises nine closely related species or genomovars. It is an important causative agent of opportunistic infections and waterborne nosocomial infections. B. cepacia (formerly genomovar I) was identified from the blood culture of a baby in our neonatal unit (NU) in March 2005. B. cepacia was isolated four times from clinical specimens since the introduction of non-touch taps in the NU from 2000 to 2005 and only once from 1994 to 2000. Environmental samples were collected from the NU, including tap water from non-touch taps. Clinical and environmental isolates of Bcc were characterized using molecular identification and strain typing. A literature review was undertaken to delineate a method for eradication of Bcc. Several variations for hot water eradication of the organism from the taps were attempted. Genotyping and molecular analysis revealed that tap water isolates were B. cenocepacia which was a different species from the B. cepacia isolated from blood cultures of the neonate. However, B. cenocepacia has been known to cause nosocomial outbreaks and it was eventually eradicated from the NU by using repeated thermal shock (hot water at 65 degrees C for 10 min), changing taps and decolonizing sinks with hypochlorite. Molecular typing is useful in assisting the investigation of Bcc nosocomial infections.

Prevention of hospital-acquired infections: review of non-pharmacological interventions

Hospital-acquired (nosocomial) infections (HAIs) increase morbidity, mortality and medical costs. In the USA alone, nosocomial infections cause about 1.7 million infections and 99 000 deaths per year. HAIs are spread by numerous routes including surfaces (especially hands), air, water, intravenous routes, oral routes and through surgery. Interventions such as proper hand and surface cleaning, better nutrition, sufficient numbers of nurses, better ventilator management, use of coated urinary and central venous catheters and use of high-efficiency particulate air (HEPA) filters have all been associated with significantly lower nosocomial infection rates. Multiple infection control techniques and strategies simultaneously ('bundling') may offer the best opportunity to reduce the morbidity and mortality toll of HAIs. Most of these infection control strategies will more than pay for themselves by saving the medical costs associated with nosocomial infections. Many non-pharmacological interventions to prevent many HAIs will also reduce the need for long or multiple-drug antibiotic courses for patients. Lower antibiotic drug usage will reduce risk of antibiotic-resistant organisms and should improve efficacy of antibiotics given to patients who do acquire infections.

A Review of the Research Literature on Evidence-Based Healthcare Design

Objective:

This report surveys and evaluates the scientific research on evidence-based healthcare design and extracts its implications for designing better and safer hospitals.

Background:

It builds on a literature review conducted by researchers in 2004.

Methods:

Research teams conducted a new and more exhaustive search for rigorous empirical studies that link the design of hospital physical environments with healthcare outcomes. The review followed a two-step process, including an extensive search for existing literature and a screening of each identified study for the relevance and quality of evidence.

Results:

This review found a growing body of rigorous studies to guide healthcare design, especially with respect to reducing the frequency of hospital-acquired infections. Results are organized according to three general types of outcomes: patient safety, other patient outcomes, and staff outcomes. The findings further support the importance of improving outcomes for a range of design characteristics or interventions, including single-bed rooms rather than multibed rooms, effective ventilation systems, a good acoustic environment, nature distractions and daylight, appropriate lighting, better ergonomic design, acuity-adaptable rooms, and improved floor layouts and work settings. Directions for future research are also identified.

Conclusions:

The state of knowledge of evidence-based healthcare design has grown rapidly in recent years. The evidence indicates that well-designed physical settings play an important role in making hospitals safer and more healing for patients, and better places for staff to work.

[Prevention of fungal infections related to the water supply in French hospitals: proposal for standardization of methods]

OBJECTIVES

The aims of this study were to assess the risk of fungal infections related to the water supply in several hospitals and to clarify the appropriate methodology in order to standardize the technical conditions of the controls and develop guidelines. It was conducted in 10 university hospital centers across the country from February 2004 through March 2005.

METHOD

A preliminary study allowed us to optimize the mycological analysis. The study was conducted under the same conditions as for bacteriological controls: water filtration through a cellulose acetate membrane cultured on agar. Departments with the highest patient risk were selected, including hematology, organ transplantation, and burn units. We selected 98 sites and sampled both water and water-related surfaces at each: three one-liter water samples (the first flow, cold and hot water) and two or three surface samples (inside the tap, pommel of the shower and siphon). At each site, a form was filled to specify its location in the unit, any water treatment (chlorine or other), filtering, and temperature. Water from taps equipped with sterilized filtration was sampled without the filter.

RESULTS

There was a significant difference (p=0.039) in the number of positive cultures between the three types of water sampled: hot water (>50 degrees C) was colonized less often than first flow or cold water. Only 4% of the hot-water samples had positive cultures, compared to the 52% of the cold-water samples. Except in two hospitals with generalized contamination of the water pipes (one with Exophiala spp and the other with Fusarium spp), colonization was usually slight. Cold water was more colonized than hot water, but 79% of the samples yielded fewer than 5CFU/L. Dematiaceous hyphomycetes were isolated; Aspergillus spp were rare. The number of CFU in surface samples (that is, biofilms) was higher (mean=15 CFU per sample) but surfaces were positive less often than water (13% compared with 43% of all water samples). Sampling from siphons was productive more often than from taps (23%), but the molds isolated differed from those in the related water. Relations to bacterial flora and P. aeruginosa were also studied, together with the effects of chemical treatment.

CONCLUSION

Current regulations require only bacteriological survey. The absence of knowledge about the threshold of contamination at which there is a risk of nosocomial invasive fungal infections makes it difficult to impose routine monitoring. Mycological surveys of water are required during hospital renovation, plumbing work, pipe maintenance and when air samples are negative during nosocomial infection investigations.

Systematic Literature Review of Oral Hygiene Practices for Intensive Care Patients Receiving Mechanical Ventilation

Background Oropharyngeal colonization with pathogenic organisms contributes to the development of ventilator-associated pneumonia in intensive care units. Although considered basic and potentially nonessential nursing care, oral hygiene has been proposed as a key intervention for reducing ventilator-associated pneumonia. Nevertheless, evidence from randomized controlled trials that could inform best practice is limited.

Objective To appraise the peer-reviewed literature to determine the best available evidence for providing oral care to intensive care patients receiving mechanical ventilation and to document a research agenda for this important activity in optimizing patients’ outcomes.

Methods Articles published from 1985 to 2006 in English and indexed in the CINAHL, MEDLINE, Joanna Briggs Institute, Cochrane Library, EMBASE, and DARE databases were searched by using the key terms oral hygiene, oral hygiene practices, oral care, mouth care, mouth hygiene, intubated, mechanically ventilated, intensive care, and critical care. Reference lists of retrieved journal articles were searched for publications missed during the primary search. Finally, the Google search engine was used to do a comprehensive search of the World Wide Web to ensure completeness of the search. The search strategy was verified by a health librarian.

Results The search yielded 55 articles: 11 prospective controlled trials, 20 observational studies, and 24 descriptive reports. Methodological issues and the heterogeneity of samples precluded meta-analysis.

Conclusions Despite the importance of providing oral hygiene to intensive care patients receiving mechanical ventilation, high-level evidence from rigorous randomized controlled trials or high-quality systematic reviews that could inform clinical practice is scarce.

Contribution of tap water to patient colonisation with Pseudomonas aeruginosa in a medical intensive care unit

This study examined tap water as a source of Pseudomonas aeruginosa in a medical intensive care setting. We prospectively screened specimens of patients, tap water and hands of healthcare workers (HCWs) over a six-month period in a 16-bed medical intensive care unit. Molecular relatedness of P. aeruginosa strains was investigated by pulsed-field gel electrophoresis. A total of 657 tap water samples were collected from 39 faucets and 127 hands of HCWs were sampled. P. aeruginosa was found in 11.4% of 484 tap water samples taken from patients' rooms and in 5.3% of 189 other tap water samples (P<0.01). P. aeruginosa was isolated from 38 patients. Typing of 73 non-replicate isolates (water samples, hands of HCWs and patients) revealed 32 major DNA patterns. Eleven (52.4%) of the 21 faucets were contaminated with a patient strain, found before isolation from tap water in the corresponding room in nine cases, or from the neighbouring room in two cases. Among seven P. aeruginosa strains isolated from HCW hands, the genotype obtained was the same as that from the last patient they had touched in six cases, and in the seventh with the last tap water sample used. More than half of P. aeruginosa carriage in patients was acquired via tap water or cross-transmission. Carriage of P. aeruginosa by patients was both the source and the consequence of tap water colonisation. These results emphasise the need for studies on how to control tap water contamination.

Impact of Copper and Silver Ionization on Fungal Colonization of the Water Supply in Health Care Centers: Implications for Immunocompromised Patients

Copper and silver ionization is a well-recognized disinfection method to control Legionella species in water distribution systems in hospitals. These systems may also serve as a potential indoor reservoir for fungi. The prevalence of fungi was significantly lower in ionized than in nonionized water samples from health care facilities. The clinical consequences of this finding require further investigation.

Infection Control Practice in Cystic Fibrosis Centers

In this article, the authors outline some of the major historical events that signaled the need to better understand mechanisms of infection in cystic fibrosis (CF). The authors discuss general principles of infection control, focusing on issues of particular importance to patients who have CF. The authors also describe the major pathogens associated with the CF airway, provide a review of findings from inpatient and outpatient studies of infection control, and provide an outline of future directions for investigation.

Hygienic safety of reusable tap water filters (Germlyser) with an operating time of 4 or 8 weeks in a haematological oncology transplantation unit

Background

Microbial safe tap water is crucial for the safety of immunosuppressed patients.

Methods

To evaluate the suitability of new, reusable point-of-use filters (Germlyser^®, Aquafree GmbH, Hamburg, Germany), three variations of a reusable filter with the same filter principle but with different outlets (with and without silver) and inner surface coating of the filter encasements (with and without nano-crystalline silver) were tested. The filter efficacy was monitored over 1, 4 and 8 weeks operating time in a haematological oncology transplantation unit equipped with 18 water outlets (12 taps, 6 showers).

Results

The filtered water fulfilled the requirements of absence of pathogens over time. From 348 samples, 8 samples (2.3%) exceeded 100 cfu/ml (no sample ≥ 500 cfu/ml). As no reprocessed filter exhibited 100% filter efficacy in the final quality control after each reprocessing, these contaminations could be explained by retrograde contamination during use.

Conclusion

As a consequence of the study, the manufacturer recommends changing filters after 4 weeks in high risk areas and after 8 weeks in moderate infectious risk areas, together with routine weekly alcohol-based surface disinfection and additionally in case of visible contamination. The filter efficacy of the 3 filters types did not differ significantly regarding total bacterial counts. Manual reprocessing proved to be insufficient. Using a validated reprocessing in a washer/disinfector with alkaline, acid treatment and thermic disinfection, the filters were effectively reprocessable and now provide tap water meeting the German drinking water regulations as well as the WHO guidelines, including absence of pathogens.