Hospital Water Supply Research Articles

Going with the Flow: Legionellosis Risk in Toronto, Canada Is Strongly Associated with Local Watershed Hydrology

Legionella species are increasingly recognized as a cause of both healthcare- and community-acquired pneumonia (so-called "Legionnaire's disease"). These pathogens are ubiquitous in the environment, but environmental factors in the occurrence of sporadic legionellosis remain poorly understood. We analyzed all legionellosis cases identified in the Greater Toronto Area of Ontario from 1978 to 2006, and evaluated seasonal and environmental patterns in legionellosis case occurrence by using both negative binomial models and case-crossover analysis. A total of 837 cases were reported during the study period. After adjusting for seasonal effects, changes in the local watershed, rather than weather, were the strongest contributors to legionellosis risk. A 3.6-fold increase (95% confidence interval (CI), 2.4-5.3) in odds of disease was identified with decreasing watershed levels approximately 4 weeks before case-occurrence. We also found a 33% increase (95% CI, 8-64%) in odds of disease with decreasing lake temperature during the same period and a 34% increase (95% CI, 14-57%) with increasing humidity 5 weeks before case-occurrence. We conclude that local watershed ecology influences the risk of legionellosis, notwithstanding the availability of advanced water treatment capacity in Toronto. Enhancement of risk might occur through direct contamination of water sources or via introduction of micronutrients or commensal organisms into residential and hospital water supplies. These observations suggest testable hypotheses for future empiric studies.

Relaxing the Protected Environment Has Not Adversely Impacted Early Outcome of Older Patients (≥ 50 years) with AML and HR- MDS Receiving Induction Therapy

Background: As part of our standard of care, patients (pts) with acute myelogenous leukemia (AML) and high risk myelodysplastic syndrome (HR-MDS) older than 50 years undergoing induction remission therapy (IC) are offered to be admitted to rooms in the “Protected Environment” (PE) unit during their therapy. The objective of this measure is to decrease the incidence of infections. Since Nov 2007 several changes were made to the PE rooms due to construction at our institution:Old PE unit (OPE)New PE unit (NPE)Use of shoe coversShoe covers should be used at the entrance of the unit and should be kept on until leaving the unit.Shoe covers should be used upon entrance to the unit and changed when entering each room.VisitationsVisitors are not allowed in the room. Visitors use a separate room for visitation.Visitors are allowed inside the room and must use gown, gloves and mask.Water filtrationWater supply for OPE was independent from main hospital water supply. Special filtration x3 was plumbed into the unit. The ice machine was plumbed with filtered water.Water from main hospital lines. Ice machine/water from main hospital lines and plumbed with a filtration system.Window BlindsSingle blind built inside the windows with an electronic switch for patient operation.Double shades inside the room operated by the patient.Both units (OPE and NPE) continue with the same HEPA filtration system with air exchanged 15 times per hour.Objective: To evaluate the impact of these changes in the incidence of infections and mortality of pts admitted to the NPE.Methods: Admission to the NPE became effective Nov 2007. We retrospectively reviewed medical records of pts who were admitted to the OPE from May 2007 to October 2007 and compared to the pts who were admitted to the NPE from Nov 2007 to May 2008.Results: 42 patients were admitted to the OPE, and 32 to the NPE. No differences were found in baseline characteristics between the 2 groups. The majority had AML [OPE=90% and NPE=84%, p=0.430] and Zubrod performance status ≥ 2 [83% and 91 %, OPE and NPE respectively, p= 0.363]. Median age was 64 yo (r: 31–89) for OPE pts and 60 (r: 18–79) for NPE. Ninety-five percent of the pts in OPE and 97% of the pts in the NPE received chemotherapy with cytarabine containing regimens; 43% and 47% of the pts had ANC <500 at start of IC (p=0.734). All pts received antifungal and antibacterial prophylaxis. There were no differences in the incidence or type of infections between the 2 groups (Table 1).OPE N= 42NPE N= 32No. pts infected, (%)35 (83)26 (81)No. infectious episodes4232Type of infections, (%)Bacteremia8 (19)3 (9)Pneumonia8 (19)7 (22)FUO23 (55)17 (53)Others3 (7)5 (16)Organisms isolated, n (%)Bacteria11 (26)7 (22)Fungi1 (2)1 (3)Virus01 (2)Clinically documented infections (%)30 (71)23 (72)At 4 weeks there was no difference in mortality between the two groups (1/42 and 0/32 for OPE and NPE, respectively, p=0.379).Conclusions: Although the NPE is less restrictive in protective measures against infections, it provides similar protection compared to the OPE. Induction remission mortality has not been adversely affected.

Comparison of two molecular methods used for subtyping of Legionella pneumophila 1 strains isolated from a hospital water supply

The results of the pulsed-field gel electrophoresis and the sequence-based typing (using the loci flaA, pilE, asd, mip, mompS and proA) were compared for subtyping of Legionella pneumophila 1 strains isolated from a hospital water supply. Molecular typing was carried out on 61 isolates (38% of the positive samples) selected on space and temporal criteria in order to follow the evolution of the water-system colonization. For all the 61 isolates, the sequence of the amplified mip gene fragment identified Legionella pneumophila strain Wadsworth. Genotype testing by PFGE analysis showed three different patterns, correspondent to three SBT types according to the allelic profiles. Both PFGE and SBT indicated the circulation and the persistence in the hospital potable water-system of three types randomly distributed in space and time. The two molecular methods adopted showed a 100% concordance, although a low degree of genetic heterogeneity characterized the isolates. The electrophoretic patterns were sufficiently unambiguous to consider PFGE a highly discriminatory typing method, but the SBT technique besides accurately characterizing isolates, was able to identify Legionella strains through analysis of the mip gene. A typing method with this level of discriminatory power has great potential for assisting in epidemiological studies.

Chronic Disseminated Mycobacterium xenopi Infection in a Cat with Idiopathic CD4+ T Lymphocytopenia

A 3-year-old castrated male domestic shorthair cat was referred for examination in August 2000 with a 3-week history of poor appetite, vomiting, and weight loss. One week before referral, evaluation by the referring veterinarian identified anemia (PCV 21% [reference range 29–48%]) and moderate renal insufficiency (BUN 55mg/dL [reference range 14–36mg/dL], serum creatinine 4.2mg/dL [reference range 0.6–2.4mg/dL], urine specific gravity 1.015) with an inflammatory urine sediment (proteinuria, white blood cells, bacteria) on a voided sample. The results of enzyme-linked immunosorbent assays for feline leukemia virus (FeLV) antigen and feline immunodeficiency virus (FIV) antibodies were negative. Radiographs disclosed bilateral renomegaly and microcardia. Abdominal ultrasound examination identified a thin cortex in the left kidney and both kidneys were hyperechoic. The cat was treated with lactated Ringer’s solution IV and enrofloxacin 6mg/kg/d IV for 3 days. Upon examination at the referral hospital, the cat was quiet and responsive. Physical examination abnormalities were limited to bilaterally enlarged kidneys that appeared to be painful on palpation and a body condition score of 3/9. Body weight was 3.6 kg. On CBC there was a severe nonregenerative macrocytic normochromic anemia (PCV 17% [reference range 30–47%], MCV 55 fL [reference range 41–51 fL], MCHC 31 g/dL [reference range 31–35 g/dL], aggregate reticulocytes 20,880/mL) in the presence of normal serum erythropoietin concentration (17mU/mL [reference range 10–30mU/mL]). The WBC count (10,200/mL [reference range 5,500–19,500/ mL]), differential cell count (segmented neutrophils 7,040/mL [reference range 2,500–12,500/mL], lymphocytes 2,860/mL [reference range 1,500–7,000/mL], monocytes 260/mL [reference range 0–800/mL], eosinophils 50/mL [reference range 0–1,500/mL]), and platelet count (485,000/mL [reference range 300,000–800,000/ mL]) were normal. Serum chemistry results indicated moderate azotemia (BUN 36mg/dL [reference range 16–34mg/dL], serum creatinine 3.5mg/dL [reference range 0.7–2.3mg/dL]), increased AST activity (173U/L [reference range 5–30U/L]), and hypoalbuminemia (1.8 g/dL [reference range 2.0–3.1 g/dL]). Results of urinalysis collected by cystocentesis indicated isosthenuria (USG 1.011), proteinuria, and bacteruria. Aerobic urine culture was negative, and plasma prothrombin and partial thromboplastin times were within normal limits. Ultrasonographic examination of the abdomen identified moderate bilateral renomegaly with pyelectasia, mesenteric lymphadenopathy, and an enlarged hypoechoic pancreas. By means of ultrasound guidance, fineneedle tissue aspirates were collected from kidney, mesenteric lymph node, and pancreas, and slides were prepared for cytologic evaluation using Wright-Giemsa stain. Preparations obtained from the kidney were very cellular, consisting primarily of large, epitheliod macrophages arranged in sheets and individually. The cytoplasm of many of the macrophages contained long, thin, negatively staining, rod-shaped inclusions consistent withMycobacteria spp. (Fig 1). Renal epithelial cells were also observed in the preparation.Macrophages containing similar negatively staining rods were observed in tissue aspirate preparations from the pancreas and a mesenteric lymph node, along with pancreatic epithelium and lym-

Detection of Legionella in Hospital Water Supply using Mip Based Primers

Detection of Legionella in Hospital Water Supply using Mip Based Primers

Interaction of Legionellae and Free-Living Amoebae Within Hospital Water Supplies

Interaction of Legionellae and Free-Living Amoebae Within Hospital Water Supplies

Isolation and identification of amoeba‐resisting bacteria from water in human environment by using an Acanthamoeba polyphaga co‐culture procedure

Amoeba-resisting bacteria (ARB) such as Legionella spp. are currently regarded as potential human pathogens living in the environment. To detect ARB from both human and environmental samples, co-culture with amoebae has been demonstrated as an efficient tool. However, using this procedure, mostly water from cooling towers and hospital water supplies have been investigated as the possible reservoir of ARB. In the present study, we studied ARB population in 77 environmental water samples including rivers, fountains, lakes and domestic wells in the south of France. As a result, a total of 244 isolates corresponding to 89 different species of ARB, but not Legionella spp., were identified. Ability to grow within and/or to be lytic for amoebae was revealed for the first time for several human pathogens. Six isolates are likely to be the members of a new or uncharacterized genus/species. An anaerobic bacterium, Clostridium frigidicarnis was demonstrated to be lytic for amoebae. This preliminary work demonstrates that the water environment in the vicinity of humans is a reservoir of ARB, including well-known pathogens for which amoebae and/or water was not recognized earlier as a possible reservoir.

P2-16 Identification of Legionella in the hot water supply of a general hospital in Isfahan

P2-16 Identification of Legionella in the hot water supply of a general hospital in Isfahan

Serratia Marcescens: An Outbreak Report from Neonatal Ward

Introduction: Serratia marcescens is a serious death-causing factor especially for premature and low birth weighted neonates, and has become an important cause of nosocomial infection over the last years. It is a motile, non-sporulating gram-negative bacillus classified in the family enterobacteriacea. This group of bacteria affect on immune system mainly in newborns. In this report, we describe the course of the outbreak we had experienced and the measures taken to control it. Materials & Methods: All of the medical records and other associated variables of patients suffered from serratia marcescens infection were studied. . Also certain procedures including cell cultures of medical equipments, water supply, sanitation of medical personels and patients, were done to find sources of the outbreak in neonatal ward (Kermanshah – Iran). Results: 565 hospitalized patients from September 2000 till March 2001 was studied.33 patients showed positive infection results with Serration Marcescens and confirmed using blood culture (68.8%), in cerebro-spinal fluid culture (23.2%) and both methods (6.8). 13 out of 33 (39.4%) patients have died. Finally it was found that the source of infection could derive from hospital water supply since after taking preventive steps such as controlling consumed water no cases were found with Serration marcescens. Conclusion: This study showed that outbreak of serratia marcescens would lead to serious in the newborn infants. Marcessence infection in newborn wards is difficult to manage and may temporarily need closure of units to new admissions and care should be exercised to control the spread. Awareness of the danger for the presence of this organism in a newborn unit and controlling its spread will be necessary to prevent life threatening infection in the high risk newborn in the future

Prospective Sampling of Patient Bath Basins in an Acute Care Setting: Qualitative Evaluation of Bacterial Colonization

BACKGROUND/OBJECTIVES: Hospital–acquired infections (HAIs) occur in 5% to 10% of patients annually and are the fifth leading cause of death in acute-care hospitals, with annual costs exceeding $6.5 billion. Potential sources of infection during patient bathing include hospital water supplies and skin of patients. Because mechanical friction during bathing releases skin flora into water, including potentially harmful pathogens, patient bath basins may be a potential etiology for HAIs. This nonrandomized, blinded, prospective study identified pathogens in patient bath basins to determine if they can be a source of bacterial colonization and increase patient risk for HAIs.

Opportunistic Aspergillus pathogens measured in home and hospital tap water by quantitative PCR (QPCR)

Opportunistic fungal pathogens are a concern because of the increasing number of immunocompromised patients. The goal of this research was to test a simple extraction method and rapid quantitative PCR (QPCR) measurement of the occurrence of potential pathogens, Aspergillus fumigatus, A. flavus, A. terreus and A. niger, in home tap water and a hospital water supply. Water samples were taken from the kitchen tap in the homes of 60 patients who were diagnosed with legionellosis. Water samples were also taken from three locations in a hospital that generated all of its hot water by flash heating. Opportunistic infectious agents Aspergillus fumigatus, A. flavus, A. terreus and A. niger were measured using QPCR. Aspergillus terreus DNA was found in 16.7% and A. fumigatus DNA in 1.7% of the samples taken from the kitchen tap. None of the Aspergillus species were found in any of the hospital water samples.The development of a simple DNA extraction method along with QPCR analysis is suitable for rapid screening of tap water for opportunistic fungal pathogens. This simple method can be used to obtain pathogen occurrence results in about 3 h, instead of waiting days to weeks for culture data. Obtaining pathogen occurrence data in a timely manner could promote the elimination of the pathogens from the water supply of immunocompromised patients.

P1867 Detection of fungi in hospital water supplies using molecular beacons

P1867 Detection of fungi in hospital water supplies using molecular beacons

Legionella pneumophila aortitis in a heart transplant recipient

We describe the case of a patient with a culture-proven infection of the ascending aorta caused by Legionella pneumophila 16 months after cardiac transplantation. Serology follow-up and surveillance culture of the hospital water supply suggested a nosocomial acquisition of the infection during the post-transplantation period. The diagnosis was made after 5 months of recurrent unexplained febrile episodes. A Teflon ring implanted around the aortic suture line during the intervention may have contributed to the unusual localization of the infection. The patient was successfully treated with antibiotics and aortic reconstruction.

Interactions between Mycobacterium xenopi, amoeba and human cells

Outbreaks due to Mycobacterium xenopi have been linked with contaminated water. M. xenopi has been shown to interact with the biofilm formed in water distribution systems and to be hosted by free-living Acanthamoeba. The present study investigated the interaction between M. xenopi and A. polyphaga amoeba, and between M. xenopi and human fibroblast HEL cells. Examination using the light microscopy together with electronic and confocal microscopy demonstrated that M. xenopi was located within the amoeba and in HEL cells. The Light Cycler measurement of the M. xenopi:A. polyphaga DNA ratio and the M. xenopi:HEL cell DNA ratio demonstrated intra-amoebal and intracellular growth of M. xenopi with doubling-times of five-days and 10 days, respectively. Intra-amoebal M. xenopi survived protozoan encystment and germination. These data demonstrate that M. xenopi is a facultative intra-amoebal and intracellular pathogen. Testing intra-amoebal M. xenopi might be necessary to properly evaluate decontamination procedures for hospital water supply systems in order to achieve eradication.

Are clinical isolates of Pseudomonas aeruginosa more virulent than hospital environmental isolates in amebal co-culture test?

Pseudomonas aeruginosa is an important opportunistic pathogen in hospital-acquired infections. As an environmental bacterium, it colonizes soil and water as well as hospital water supply and shares its natural habitat with free-living amebae. It has been shown previously that an ameba host system can be used to analyze the virulence of P. aeruginosa strains. In this study we have developed a simple amebal co-culture test with Acanthamoeba polyphaga to compare the virulence of P. aeruginosa between human and environmental isolates. Experimental study. The four state hospitals Intensive of Marseille. Eighty-one environmental strains isolated from the hospital water and 69 clinical isolates of P. aeruginosa (52 from blood cultures and 17 from bronchoalveolar lavage) were tested in the amebal co-culture test. The results show that compared with environmental isolates, the isolates of P. aeruginosa from blood cultures were significantly more virulent in the ameba assay (37% vs. 62%, p=.006). These data suggest that clinical infections due to Pseudomonas aeruginosa are due, at least in part, to bacterial virulence. Furthermore, even within the constraints of small sample size, virulence of respiratory isolates is significantly correlated with the occurrence of P. aeruginosa bacteremia. Our results, as those published previously, suggest that at the strain level, acquisition of antimicrobial resistance is correlated with the diminution of virulence. However, at the population level, clinical isolates are more virulent as well as more frequently resistant to antibiotics, presumably due to acquisition of strains mostly through cross-contaminations.

Clinical and environmental distribution of Legionella pneumophila in a university hospital in Italy: efficacy of ultraviolet disinfection

The molecular epidemiology of Legionella pneumophila in the 'V. Monaldi' University Hospital was studied. Seven cases of nosocomial Legionnaires' disease were diagnosed between 1999 and 2003. Two clinical legionella strains obtained from two patients in the adult cardiac surgery unit (CSU) and 30 environmental legionella strains from the paediatric and adult CSUs, neonatal intensive care unit (NICU) and the cardiorespiratory intensive care unit (CR-ICU) were serotyped and genotyped. L. pneumophila serogroup 1/Philadelphia with an identical pulsed-field gel electrophoresis (PFGE) profile A was isolated from two patients in the adult CSU, and from three and one water samples taken in the adult CSU and the paediatric CSU, respectively, from 2001 to 2002. Furthermore, L. pneumophila serogroup 3 with an identical PFGE profile B was identified in 20 environmental strains from all wards, L. pneumophila serogroup 3 with PFGE profile C was identified in a single environmental strain from the CR-ICU, and non-pneumophila Legionella with identical PFGE profile D was identified in five environmental strains from the adult CSU, paediatric CSU and NICU. Ultraviolet irradiation was effective in disinfection of the hospital water supplies in the adult and paediatric CSUs contaminated by L. pneumophila clone associated with nosocomial Legionnaires' disease. In conclusion, these data demonstrate that two cases of nosocomial legionellosis were caused by the persistence of a single clone of L. pneumophila serogroup 1/Philadelphia in the hospital environment, and that disinfection by ultraviolet irradiation may represent an effective measure to prevent nosocomial Legionnaires' disease.

P9.10 Legionella Control in a Hospital Water Supply System: Missing Sieves in Thermostatic Mixers Causing a Persisting Problem

P9.10 Legionella Control in a Hospital Water Supply System: Missing Sieves in Thermostatic Mixers Causing a Persisting Problem

Nature of bacteria found on some wards in Sultan Qaboos University Hospital, Oman

This study aims to determine what objects lying in the hospital environment or brought in from outside contribute to the introduction of bacteria associated with nosocomial infections. One hundred swab specimens collected from children’s toys, sinks, door handles, telephone handsets and flowers brought into the hospital were plated on different culture media. Colonial growth on the media was purified and identified subsequently using standard bacteriological methods. Of the 100 samples cultured, 61 (61%) grew a range of bacteria including Pseudomonas aeruginosa (n=14, 23.0%), Acinetobacter spp. (n=13, 21.3%), Serratia spp. (n=9, 14.7%), Staphylococcus epidermidis (n=9, 14.7%), Stenotrophomonas maltophilia (n=4, 6.6%), Staphylococcus aureus (n=4, 6.6%), Enterobacter cloacae (n=3, 4.9%), Pantoea sp. (n=2, 3.3%), Chryseobacterium sp. (n=2, 3.3%) and Klebsiella pneumoniae (n=1, 1.6%). Although all the Serratia, Enterobacter, Klebsiella and Pantoea species isolates showed varying degrees of resistance to gentamicin, ceftriaxone, cefuroxime and cefotaxime, all were resistant to ampicillin. Chryseobacterium and Stenotrophomonas species isolates were resistant to amikacin, imipenem, gentamicin and ceftazidime, to which only three isolates of Pseudomonas species were resistant. All the staphylococcal isolates were susceptible to methicillin. Although there has been no major outbreak of a nosocomial infection in the hospital, it is strongly recommended that effective control measures (e.g., sampling the hospital water supply, disinfecting children’s toys, use of appropriate hand washing and checking some of the disinfectants for presence of bacteria) are needed. These measures are necessary to ensure that the antibiotic-resistant strains identified in this study are not allowed to spread in the hospital.

Abbreviated duration of superheat-and-flush and disinfection of taps for Legionella disinfection: Lessons learned from failure

One medical center in southern Taiwan faced an outbreak of nosocomial Legionnaires' disease; a total of 81 suspected cases were detected during an 8-month period. Baseline environmental surveillance showed that 80% of the distal sites in intensive care units (ICUs) were positive for Legionella pneumophila. Superheat-and-flush was selected for hospital water supply disinfection because it required no special equipment, and it can be initiated expeditiously. We conducted 2 episodes of superheat-and-flush based on the published recommendations from the Department of Health, Taiwan; US Centers for Disease Control and Prevention; and American Society of Heating, Refrigerating, and Air-Conditioning Engineers. Both flushes failed to control colonization of Legionella in the hospital water supply. The rate of distal sites positive for Legionella in wards and ICUs was 14% and 66%, respectively, 10 days after the second flush. The effect of replacement of faucets and showerheads in ICUs appeared to be insignificant in colonization of Legionella. The application of superheat-and-flush for flush duration of 5 minutes was ineffective. Superheat-and-flush may not be economic for a large medical center because it could be costly and labor intensive.

Point-of-care controls for nosocomial legionellosis combined with chlorine dioxide potable water decontamination: a two-year survey at a Welsh teaching hospital

This study reports a two-year programme of attempted eradication of Legionella colonization in the potable water supply of a 1000-bed tertiary care teaching hospital in Wales. There was a simultaneous, point-of-care, sterile-water-only policy for all intensive care units (ICU) and bone marrow and renal transplant units in order to prevent acquisition of nosocomial Legionnaires' disease. The programme was initiated following a case of nosocomial pneumonia caused by Legionella pneumophila serogroup 1-Bellingham-like genotype A on the cardiac ICU. The case occurred 14 days after mitral and aortic valve replacement surgery. Clinical and epidemiological investigations implicated aspiration of hospital potable water as the mechanism of infection. Despite interventions with chlorine dioxide costing over 25000 UK pounds per annum, Legionella has remained persistently present in significant numbers (up to 20000 colony forming units/L) and with little reduction in the number of positive sites. Two further cases of nosocomial disease occurred over the following two-year period; in one case, aspiration of tap water was implicated again, and in the other case, instillation of contaminated water into the right main bronchus via a misplaced nasogastric tube was implicated. These cases arose because of inadvertent non-compliance with the sterile-water-only policy in high-risk locations. Enhanced clinical surveillance over the same two-year period detected no other cases of nosocomial disease. This study suggests that attempts at eradication of Legionella spp. from complex water systems may not be a cost-effective measure for prevention of nosocomial infections, and to the best of our knowledge is the first study from the UK to suggest that the introduction of a sterile-water-only policy for ICUs and other high-risk units may be a more cost-effective approach.