Cold Water Samples Research Articles

Disparity in disinfection byproducts concentration between hot and cold tap water

The quality of water entering a distribution system may differ substantially from the quality at the point of exposure to the consumer. This study investigated temporal variations in the levels of regulated and non-regulated disinfection byproducts (DBPs) in cold and hot tap water in a home on a medium-sized municipal water system. In addition, samples were collected directly from the water plant with some being held in accordance with a simulated distribution system (SDS) test protocol. The location for this work was a system in western Massachusetts, USA that uses free chlorine as a final disinfectant. Very little short term variability of DBPs at the point of entry (POE) was observed. The concentration of DBPs in the time-variable SDS test was similar to concentrations in the cold water tap. For most DBPs, the concentrations continued to increase as the cold water tap sample was held for the time-variable SDS incubation period. However, the impact of heating on DBP levels was compound specific. For example, the concentrations of trihalomethanes (THMs), dichloroacetic acid (DCAA) and chloropicrin (CP) were substantially higher in the hot water tap than in the cold water time-variable SDS samples. In contrast, the concentration of trichloroacetic acid (TCAA) was lower in the heated hot tap water, but about equal to that observed in the cold tap water. The situation was more pronounced for dichloroacetonitrile (DCAN), bromodichloroacetic acid (BDCAA), bromochloroacetic acid (BCAA) and 1,1,1-trichloropropanone (TCP), which all showed lower concentrations in the hot water then in either of the cold water samples (instantaneous or time-variable SDS). The latter was viewed as a clear indication of thermally-induced decomposition. The ratio of unknown total organic halide (UTOX) to TOX was substantially lower in the hot tap water as the THM to TOX ratio became correspondingly larger. The results of this study show that DBP exposure in the home is not well represented by concentrations measured in cold water taps where most compliance monitoring is done.

Microstructure and Properties of Thermal Sprayed ZrO<sub>2</sub>-NiCr Coatings

NiCr/ZrO2gradated coatings were obtained on C45 carbon steel by high velocity arc spraying and micro-plasma spraying to improve the mechanical and thermal behaviors of the carbon steel. Scanning electronic microscope (SEM) and X-ray diffraction (XRD) were employed to characterize the microstructure of the prepared composite coatings. Mechanical properties including hardness and bonding strength were also evaluated by microhardness tester and electron tensile tester. The thermal shock behaviors were investigated by quenching the coating samples in cold water from 900 °C and 1100 °C, respectively. The oxidation of NiCr/ZrO2gradated coating and C45 carbon steel substrate were carried out for up to 108 hours in air atmosphere at 1100°C. The oxidation behaviors were investigated after detailed examinations by thermal gravimetric analysis. Experimental results indicate that NiCr/ZrO2gradated coating exhibit a much higher hardness and high temperature oxidation behavior than the substrate. The bonding strength and thermal shock behavior of NiCr/ZrO2are superior to pure ZrO2coating, which could be mainly attributed to the NiCr intermediate graded layer due to the microstructure improvement and relaxation of residual stress concentration.

Evaluation of Legionella presence in the water system of a public building by semi-nested polymerase chain reaction as a rapid screening method complementary to plate count

The aim of this study was to apply a fast and efficient protocol for monitoring levels of Legionella contamination in high-risk water systems using molecular techniques and culture methods. Forty-nine water samples from a public building were analyzed by a culture method (BCYE agar) and a specific semi-nested polymerase chain reaction (PCR). The first 30 analyses using plate counts were positive in 28% of hot water and 8% of cold water samples. The analysis by PCR, obtained within 24 h of collection, revealed the presence of DNA in 100 and 54% respectively. Only four PCR results coincided with the cultures. A second survey (19 samples) was performed 1 year later. Semi-nested PCR revealed that 53% of the samples were positive; however, plate counts yielded no positive results. The 16S rRNA sequence comparison between the first and second samplings showed 100% homology. In conclusion, the study of the design of the building's water system, the use of a fast screening semi-nested PCR and a culture method for the detection of Legionella allowed accurate assessment of the contamination, thus contributing to the early implementation of measures to eliminate the presence of the bacteria in water systems and consequently reduce a latent public health risk.

The influence of laser treatment on thermal shock resistance of plasma-sprayed nanostructured yttria stabilized zirconia thermal barrier coatings

Abstract The main goal of this paper was to evaluate the effects of laser glazing on the microstructure and thermal shock resistance of nanostructured thermal barrier coatings (TBCs). To this end, nanostructured yttria stabilized zirconia (YSZ) top coat and NiCrAlY bond coat were deposited on Inconel 738LC substrate by air plasma spraying (APS). The Nd:YAG pulsed laser was used for laser treatment of top coat surface. The thermal shock behavior of plasma-sprayed and laser-glazed coatings was investigated by quenching the samples in cold water from 1000 °C. The microstructure and phase composition of the coatings were characterized by scanning electron microscopy (SEM) and X-ray diffractometry (XRD). Energy dispersive spectroscopy (EDS) was used to analyze the interface diffusion behavior of the bond coat elements. The results of SEM revealed that the laser glazing process reduced the surface roughness, eliminated the porosity of the surface and produced network cracks perpendicular to the surface. XRD results also indicated that both as-sprayed and laser glazed coatings consisted of non-transformable (T′) phase. Thermal shock test results showed that the lifetimes of the plasma-sprayed TBCs were almost doubled by laser glazing. Continuous network of segmented cracks perpendicular to the surface produced by laser glazing improved the strain accommodation and recognized it as the main enhancement mechanism for TBC life extension.

Isolation of nontuberculous mycobacteria from hospital waters in Turkey

Nontuberculous mycobacteria (NTM) are ubiquitous in hot and cold water distribution systems. With molecular typing methods it was shown that water can be the source of colonization and infection with NTM. The aim of our study was the investigation of NTM in hot and cold water samples taken from various departments of two hospitals in Istanbul, Turkey. Totally, 160 water samples were examined. The temperature, pH, and free chlorine levels of water samples were measured between 10-41 °C, 6.78-7.98 and <0.3-0.5 mg/L, respectively. NTM were detected in 33 (20.6%) samples. Totally 20 (60.6%), 10 (30.3%) and 3 (9.1%) isolates were identified as Mycobacterium lentiflavum, Mycobacterium gordonae, and Mycobacterium peregrinum, respectively. M. lentiflavum, which was the most frequently isolated NTM, is characterized by multiple resistance to antimycobacterial drugs. Although no infections with this mycobacterium were reported from our country so far, preventive measures may be considered in patients under immunosuppression. Because no significant correlations were found among the presence of NTM or species distribution and water temperature, pH or free chlorine levels, other factors need to be investigated.

Comparison of thermal shock resistances of plasma-sprayed nanostructured and conventional yttria stabilized zirconia thermal barrier coatings

The main goal of the current study is evaluation and comparison of thermal shock behavior of plasma-sprayed nanostructured and conventional yttria stabilized zirconia (YSZ) thermal barrier coatings (TBCs). To this end, the nanostructured and conventional YSZ coatings were deposited by atmospheric plasma spraying (APS) on NiCoCrAlY-coated Inconel 738LC substrates. The thermal shock test was administered by quenching the samples in cold water of temperature 20–25°C from 950°C. In order to characterize elastic modulus of plasma-sprayed coatings, the Knoop indentation method was employed. Microstructural evaluation, elemental analysis, and phase analysis were performed using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffractometry (XRD) respectively. The results revealed that failures of both nanostructured and conventional TBCs were due to the spallation of ceramic top coat. Thermal stresses caused by mismatch of thermal expansion coefficients between the ceramic top coat and the underlying metallic components were recognized as the major factor of TBC failure. However, the nanostructured TBC, due to bimodal unique microstructure, presented an average thermal cycling lifetime that was approximately 1.5 times higher than that of the conventional TBC.

Isotope and hydrochemical assessment of the Samothraki Island geothermal area, Greece

Thermal and cold water samples were collected from the island of Samothraki, in the northern part of the Aegean Sea. Isotopic (δD, δ18O, δ34SSO4, δ34SS2−, δ18OSO4) and chemical analyses (major ions, Br, B, Li, SiO2) were performed in most of them. The study of ionic and isotopic contents shows that, the thermal waters of Samothraki Island are mainly locally fed groundwater that changes, chemically and isotopically, during its circulation within a major fracture zone reaching great depths. More specifically, the evaluation of the entire dataset indicates that water–rock reactions and mixing with brines are the principal sources of the isotopic and salinity fingerprint of these waters.The isotopic [δ18O (SO42−–H2O)] and chemical geothermometers applied on the waters of the thermal springs, suggest the probable existence of a geothermal reservoir of high enthalpy. The temperature attributed to this deep geothermal field is higher than 220°C.

Contamination of the cold water distribution system of health care facilities by Legionella pneumophila: Do we know the true dimension?

German water guidelines do not recommend routine assessment of cold water for Legionella in healthcare facilities, except if the water temperature at distal sites exceeds 25°C. This study evaluates Legionella contamination in cold and warm water supplies of healthcare facilities in Hesse, Germany, and analyses the relationship between cold water temperature and Legionella contamination. Samples were collected from four facilities, with cases of healthcare-associated Legionnaires' disease or notable contamination of their water supply. Fifty-nine samples were from central lines and 625 from distal sites, comprising 316 cold and 309 warm water samples. Legionella was isolated from central lines in two facilities and from distal sites in four facilities. 17% of all central and 32% of all distal samples were contaminated. At distal sites, cold water samples were more frequently contaminated with Legionella (40% vs 23%, p <0.001) and with higher concentrations of Legionella (≥1,000 colony-forming unit/100 ml) (16% vs 6%, p<0.001) than warm water samples. There was no clear correlation between the cold water temperature at sampling time and the contamination rate. 35% of cold water samples under 20 °C at collection were contaminated. Our data highlight the importance of assessing the cold water supply of healthcare facilities for Legionella in the context of an intensified analysis.

Characterization of aerobic heterotrophic bacteria in cold and nutrient-poor freshwater ecosystems

Aerobic heterotrophic bacteria present in the surface water of three cold and nutrient-poor lakes in the Chilean Patagonia (Alto Reino, Las Dos Torres and Venus) were analysed for genetic similarity and metabolic diversity using 16S ribosomal DNA and the Biolog EcoPlateTM system, respectively. Bacterial fingerprints of water samples in enriched and non-enriched nutrient broth demonstrated a >50% fingerprinting similarity between the lakes. Metabolic activity was also similar. However, the Biolog EcoPlateTM system carbon substrates revealed functional diversity. Lake Las Dos Torres showed the most fingerprinting similarity between enriched and non-enriched cold water samples. The amounts of living and viable bacteria were also higher in this lake’s water sample, suggesting a predominance of facultative oligotrophic groups. DNA sequencing analysis demonstrated the presence of phylum Bacteroidetes in Lake Alto Reino; phyla Bacteroidetes and Gammaproteobacteria in Lake Las Dos Torres; and phyla Bacteroidetes, Alphaproteobacteria, and Gammaproteobacteria in Lake Venus. Although each lake had a unique bacterial community structure, the different bacterial groups may be performing similar metabolic functions, given the similarity in extreme environmental conditions.

Comparison of the isotope hydrogeological features of thermal and cold karstic waters in the Denizli Basin (Turkey) and Buda Thermal Karst (Hungary)

Abstract The isotopic compositions of the Hungarian warm and cold water samples are spread in a wide range along the Global Meteoric Water Line (GMWL), which is a result of the significant change in the climate (mainly temperature) during infiltration (Last Glaciation and Holocene) and of the mixing process along the fault zone. The thermal karst water is isotopically lighter as it was infiltrated in a 7 to 9 °C cooler climate in the Ice Age. However, in the Denizli Basin isotopic composition of all of the thermal, lukewarm and cold waters varies in a relatively narrow range, with the exception of some warm waters whose d18O values have been shifted as a result of water-rock interaction. Isotope data prove that all the waters in the Denizli Basin infiltrated in the Holocene under more or less the same climate, so these waters are young indicating much shorter transit time from the recharge to the discharge areas because of faster flow under the surface or shorter path of the subsurface flow.

Filamentous fungi recovered from the water distribution system of a Belgian university hospital

A study was carried out over a 4-month winter period in order to assess the presence of filamentous fungi in the water distribution system of the University Hospital of Liège. A total of 197 hot and cold water samples were collected from the main water supply lines and from the taps at three different hospital sites. Overall, filamentous fungi were recovered from 55% and 50% of the main water distribution system and tap water samples, respectively, with a mean of 3.5 ± 1.5 colony forming units per 500 ml water. Nine different genera were identified, all belonging to the Hyphomycetes class. Aspergillus spp. were recovered from 6% of the samples of the water distribution system and A. fumigatus was the most frequently recovered species (66.6%). However, this species was not isolated from water taps. Fusarium spp. was predominant at one site, where it was found in 28% of tap water samples. No Aspergillus spp. but some Fusarium spp. isolates were identified in samples collected from high-risk units. Filters were introduced at the point-of-use in the haematology unit after completion of the study. The findings of the present study confirm the need for further documented studies to evaluate the safety of the hospital water system and to define new preventive measures.

Évaluation des risques microbiologiques hydriques associés à Stenotrophomonas maltophilia et Pseudomonas aeruginosa au CHU d’Amiens

Background Pseudomonas aeruginosa (Psa) and Stenotrophomonas maltophilia (Smalto) are major opportunistic waterborne pathogens causing hospital-acquired infections. This study aimed to assess the biocontamination level of cold water used in Amiens’ university hospital wards, from March to June 2008. Methods We cultivated 122 pairs of cold water first jet and taps cotton-swabs on Cetrimide agar for Psa, on Stenotrophomonas maltophilia selective medium with coloured indicator (SM2i) for Smalto, on Mueller Hinton agar used as isolation medium reference for both, 48 h at 30 °C. Data analysed with Épi-Info 6.04dFr were compared with chi 2 test, significant at p < .05. Results Psa and Smalto were isolated in 26.2 and 14.8% of water samples and in 21.3 and 10.7% of swab samples respectively. They were associated in 11.5% of water samples and 5% of swab samples. Psa was alone in 13.1% of water samples and 7.4% of swab samples whereas Smalto was found in 6.6% of water and 2.5% of swabs. Psa and Smalto were isolated from 14.8% of water samples and 8.2% of swab samples of the same tap. Finally, respectively 35.2 and 17.2% of the cold water taps were biocontaminated by Psa and Smalto. In fact, microbiologic water taps contamination risk was two-fold higher for Psa than for Smalto, p < .001, without variation between wards. Conclusion Sm2i and Cetrimide are suited and efficient medium respectively for Smalto and Psa isolation. Cold-water samples are sufficient for waterborne pathogens biocontamination risk appraisal. Our results urged healthcare workers on efficient water fittings microbiologic risk control to prevent healthcare associated waterborne infections, notably due to Psa and Smalto.

Hydrogeochemical characteristics and genetic implications of Edipsos thermal springs, north Euboea, Greece

Abstract Edipsos area, situated in northern Euboea, has been well known since ancient times for the existence of thermal springs. In order to assess the hydrogeochemical conditions, thermal and cold water samples were collected and analyzed by ICP method for major and trace elements. The results revealed the direct impact of seawater, a process which is strongly related to the major tectonic structures of the area. Seawater impact was confirmed by the Cl/Br and Na/Cl ionic ratios, as well as from statistical processing and graphical interpretation of the analytical results, which classified the sampled waters into three groups (two for cold waters and one for the thermal ones). Trace element ranges for thermal waters are: As (44–84 ppb), Pb (23–154 ppb), Ag (1–2 ppb), Mn (31–680 ppb), Cu (61–97 ppb), Cs (66–244 ppb), Se (0–76 ppb), Li (732–3269 ppb), Fe (0–1126 ppb), Sr (14000–34100 ppb), B (4300–9600 ppb). Compared with the chemical composition of other thermal springs from the Hellenic Volcanic Arc, Edipsos thermal waters are enriched in Ca2+, Na+, Cl−, SO4 2−, Li, B and K+, reflecting the influence from seawater. Cold waters are free of heavy metals compared with other natural waters and are characterized by good quality based on the major element chemistry. Finally, several geothermometers were applied in order to assess the reservoir temperatures, but none of them appear to be applicable, mainly due to the impact of seawater on the initial hydrogeochemistry of the geothermal fluids.

Effects of thermal cycling on static bearing strength of pin‐connected carbon/PPS composites

AbstractIn this study, the effects of thermal cycling and water absorption on interlaminar shear strength (ILSS) and static bearing capacity of pin‐connected carbon fiber‐reinforced polyphenilenesulphide (PPS) matrix composites are investigated. Composite samples having [0o/90o]3s stacking sequence were used in the experiments and were exposed to 100 thermal cycles (one thermal cycle is composed of immersing and keeping samples in cold water and then immersing and keeping samples in hot water). ILSS and static bearing strength of pin connections were performed by using Instron 4411. According to the results, there are differences in ILSS values and pin‐connected static bearing capacities between the original samples and samples that are exposed to thermal cycling. Also the geometric parameters of end distance from the hole center (E), width of the plate (W), and pin diameter (D) remarkably affect the load bearing performance of the materials. In addition, according to the fractographic investigations using scanning electron microscope, it is observed that the fracture morphology of the samples is strongly affected by thermal cycling. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers

Comparison of thermal shock behaviors between plasma-sprayed nanostructured and conventional zirconia thermal barrier coatings

NiCoCrAlTaY bond coat was deposited on pure nickel substrate by low pressure plasma spraying(LPPS), and ZrO 2-8%Y 2O 3 (mass fraction) nanostructured and ZrO 2-7%Y 2O 3 (mass fraction) conventional thermal barrier coatings(TBCs) were deposited by air plasma spraying(APS). The thermal shock behaviors of the nanostructured and conventional TBCs were investigated by quenching the coating samples in cold water from 1 150, 1 200 and 1 250 °C, respectively. Scanning electron microscopy(SEM) was used to examine the microstructures of the samples after thermal shock testing. Energy dispersive analysis of X-ray(EDAX) was used to analyze the interface diffusion behavior of the bond coat elements. X-ray diffractometry(XRD) was used to analyze the constituent phases of the samples. Experimental results indicate that the nanostructured TBC is superior to the conventional TBC in thermal shock performance. Both the nanostructured and conventional TBCs fail along the bond coat/substrate interface. The constituent phase of the as-sprayed conventional TBC is diffusionless-transformed tetragonal( t′). However, the constituent phase of the as-sprayed nanostructured TBC is cubic( c). There is a difference in the crystal size at the spalled surfaces of the nanostructured and conventional TBCs. The constituent phases of the spalled surfaces are mainly composed of Ni 2.88Cr 1.12 and oxides of bond coat elements.

Pre-spawning water temperature affects sperm respiration and reactivation parameters in male carps

Concentration, ability to motility, motility during the second activation (reactivation), and endogenous respiration were studied in sperm from two experimental groups of carp males. Group 1 was maintained for 7 days at 15 degrees C (cold water (CW) group), whereas the second group was subjected to a temperature of 20 degrees C (warm water (WW) group) before sperm sampling. Reactivation were achieved after incubation of firstly activated sperm in media with osmotic pressure adjusted up to 300 mOsm*kg(-1) by increasing K(+) concentration. Statistically significant reduction of spermatozoa concentration in CW samples versus WW (from 46.0 +/- 12.5 (15 degrees C) to 59.3 +/- 7 10(9) (20 degrees C) spermatozoa /ml) have been observed. The sperm of the CW group required a significantly longer incubation time (37 min) under isotonic conditions to achieve a maximum percentage of potent motility at repeated activation than the WW group (23 min). After activation of sperm motility, an increase of respiration rate up to maximum level has been found, this level remained the same under condition of recovering the potential to repeated activation. During the sperm movement respiration rate, in CW group (6.1 nmol O(2)/min/10(9)spermatozoa) and WW (3.9 nmol O(2)/min/10(9)spermatozoa), was significant higher compared to nonactivated sperm (2.4 nmol O(2)/min/10(9)spermatozoa for CW and 1.1 nmol O(2) /min/10(9)spermatozoa for WW). And keeping males for 7 days at 15 degrees C increase the respiration rate of sperm.

Legionella species colonization of water distribution systems, pools and air conditioning systems in cruise ships and ferries.

BackgroundLegionnaires' disease continues to be a public health concern in passenger ships. This study was scheduled in order to investigate Legionella spp. colonization of water distribution systems (WDS), recreational pools, and air-conditioning systems on board ferries and cruise ships in an attempt to identify risk factors for Legionella spp. colonization associated with ship water systems and water characteristics.MethodsWater systems of 21 ferries and 10 cruise ships including WDS, air conditioning systems and pools were investigated for the presence of Legionella spp.ResultsThe 133 samples collected from the 10 cruise ships WDS, air conditioning systems and pools were negative for Legionella spp. Of the 21 ferries WDS examined, 14 (66.7%) were legionellae-positive. A total of 276 samples were collected from WDS and air conditioning systems. Legionella spp. was isolated from 37.8% of the hot water samples and 17.5% of the cold water samples. Of the total 96 positive isolates, 87 (90.6%) were L. pneumophila. Legionella spp. colonization was positively associated with ship age. The temperature of the hot water samples was negatively associated with colonization of L. pneumophila serogroup (sg) 1 and that of L. pneumophila sg 2 to 14. Increases in pH ≥7.8 and total plate count ≥400 CFU/L, correlated positively with the counts of L. pneumophila sg 2 to 14 and Legionella spp. respectively. Free chlorine of ≥0.2 mg/L inhibited colonization of Legionella spp.ConclusionWDS of ferries can be heavily colonized by Legionella spp. and may present a risk of Legionnaires' disease for passengers and crew members. Guidelines and advising of Legionnaires' disease prevention regarding ferries are needed, in particular for operators and crew members.

Detection of non-tuberculous mycobacteria in hospital water by culture and molecular methods

Non-tuberculous mycobacteria (NTM) are emerging pathogens in immunocompromised patients. Therefore, it is important for hospitals to consider tap water as a source for these infections. Aim of the study was to establish highly sensitive and specific techniques to detect and identify NTM in hospital drinking water. A Mycobacterium genus-specific 16S rDNA-based real-time LightCycler PCR assay with internal inhibition control and a M. xenopi-specific PCR were developed. Ninety-three water samples from 53 taps from 4 hospitals were investigated. NTM were cultured from 21 of 49 (43%) cold and 32 of 44 (73%) warm water samples. M. chelonae, M. flavescens, M. frederiksbergense, M. gordonae, M. moriokaense, M. mucogenicum, M. vaccae, and M. xenopi were identified with molecular methods. All 93 water samples were positive in the genus-specific PCR. M. xenopi DNA was detected in 40 of 44 (91%) warm and 33 of 49 (67%) cold water samples including 45 of 65 (69%) M. xenopi culture-negative samples. In conclusion, selective culture followed by molecular identification methods enabled detection of rare species of NTM in hospital drinking water and may be used in further studies investigating the epidemiology of NTM in water samples. The real-time PCR assays have a high sensitivity and allow rapid quantification of mycobacterial DNA in water samples.

Surveillance mycologique de l’eau pour la prévention des mycoses invasives dans les établissements de santé: Propositions de standardisation des méthodologies

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.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.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.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.

Mycobacterium avium in a shower linked to pulmonary disease

Mycobacterium avium was isolated from hot and cold water samples and from sediment (biofilm) collected from the showerhead in the home of a woman with M. avium pulmonary disease lacking known M. avium risk factors. IS1245/IS1311 DNA fingerprinting demonstrated that M. avium isolates from the hot and cold water and showerhead sediment demonstrated a clonal relationship with the patient's M. avium isolate. The data provide evidence that showers may serve as sources of infection by waterborne M. avium.