Chitosan Coagulation to Improve Microbial and Turbidity Removal by Ceramic Water Filtration for Household Drinking Water Treatment.

The use of porous ceramic filters is promoted globally for household water treatment, but these filters are ineffective in removing viruses from water. In order to increase virus removal, we combine a promising natural coagulant, chitosan, as a pretreatment for ceramic water filters (CWFs) and evaluate the performance of this dual barrier water treatment system. Chitosan is a non-toxic and biodegradable organic polymer derived by simple chemical treatments from chitin, a major source of which is the leftover shells of crustacean seafoods, such as shrimp, prawns, crabs, and lobsters. To determine the effectiveness of chitosan, model test water was contaminated with Escherichia coli K011 and coliphage MS2 as a model enteric bacterium and virus, respectively. Kaolinite clay was used to model turbidity. Coagulation effectiveness of three types of modified chitosans was determine at various doses ranging from 5 to 30 mg/L, followed by flocculation and sedimentation. The pre-treated supernatant water was then decanted into the CWF for further treatment by filtration. There were appreciable microbial removals by chitosan HCl, acetate, and lactate pretreatment followed by CWF treatment, with mean reductions (95% CI) between 4.7 (± 1.56) and 7.5 (± 0.02) log10 for Escherichia coli, and between 2.8 (± 0.10) and 4.5 (± 1.04) log10 for MS2. Turbidity reduction with chitosan treatment and filtration consistently resulted in turbidities < 1 NTU, which meet turbidity standards of the US EPA and guidance by the World Health Organization (WHO). According to WHO health-based microbial removal targets for household water treatment technology, chitosan coagulation achieved health protective targets for both viruses and bacteria. Therefore, the results of this study support the use of chitosan to improve household drinking water filtration processes by increasing virus and bacteria reductions.

Human health-related ecosystem services of avian-dense coastal wetlands adjacent to a Western Lake Erie swimming beach.

Wetlands provide many valuable ecosystem services, including water quality improvement to protect downstream aquatic ecosystems such as lakes, rivers, and estuaries. However, their ability to improve water quality to safe levels for direct human exposure while largely surrounded by agricultural lands and hosting large wildlife populations remains unknown. Our aim was to examine the ecosystem service capabilities of an avian-dense coastal wetland surrounded by agricultural lands along the southwestern shore of Lake Erie in Ohio by assessing the quality of water as it flows through the wetland (Ottawa National Wildlife Refuge (ONWR)) and into Lake Erie beach waters. Our study used total phosphorus and fecal indicator (Escherichia coli) concentrations as water quality metrics across the wetland and at an adjacent Lake Erie swimming beach during the 2012 summer swim season. E. coli and total P levels were consistently highest at the site, where water enters the ONWR (mean E. coli = 507 CFU/100 mL; mean total P = 535 µg/L), and steadily decreased as water flowed through the wetland and into the adjacent beach (mean E. coli = 10 CFU/100 mL; mean total P = 41 µg/L). E. coli and total P showed statistically significant (α = 0.01) correlations with phycocyanin, chlorophyll-a, turbidity, specific conductivity, dissolved oxygen, and pH; total P was also significantly correlated with total N. The results suggest that this wetland may be contributing to improving water quality, which is beneficial for human health as well as to downstream ecosystem health (e.g., limiting eutrophication promoting conditions, etc.).

Water quality trends in the last decade for ten watersheds dominated by diffuse pollution in Québec (Canada).

The aim of this work is to evaluate and discuss river water quality trends over the last decade in ten watersheds where diffuse pollution represents more than half of the annual load of phosphorus (P) and nitrogen (N). Trend analyses taking into account flow data indicate a significant reduction of total P in eight rivers, of ammonia N in five rivers, of nitrate + nitrite in four rivers, of total filtered N in three rivers and of suspended solids in two rivers. An increase of turbidity was observed in four rivers and, for fecal coliforms, no trends. P decrease can be explained by reduced mineral P inputs on cropped lands related to means such as agro-environmental fertilization plans and addition of phytase in pig and poultry feed. However, for seven of them, median P concentrations remain at least two times greater than the Québec water quality guideline for protection of rivers against eutrophication. Concentrations of other parameters remain problematic in some rivers too. These results indicate the need to continue the efforts for further diffuse pollution reduction. Future work should better quantify actions taken at the watershed scale to reduce diffuse pollution.

Electrochemical disinfection: an efficient treatment to inactivate Escherichia coli O157:H7 in process wash water containing organic matter.

The efficacy of an electrochemical treatment in water disinfection, using boron-doped diamond electrodes, was studied and its suitability for the fresh-cut produce industry analyzed. Tap water (TW), and tap water supplemented with NaCl (NaClW) containing different levels of organic matter (Chemical Oxygen Demand (COD) around 60, 300, 550 ± 50 and 750 ± 50 mg/L) obtained from lettuce, were inoculated with a cocktail of Escherichia coli O157:H7 at 105 cfu/mL. Changes in levels of E. coli O157:H7, free, combined and total chlorine, pH, oxidation-reduction potential, COD and temperature were monitored during the treatments. In NaClW, free chlorine was produced more rapidly than in TW and, as a consequence, reductions of 5 log units of E. coli O157:H7 were achieved faster (0.17, 4, 15 and 24 min for water with 60, 300, 500 and 750 mg/L of COD, respectively) than in TW alone (0.9, 25, 60 min and 90 min for water with 60, 300, 600 and 800 mg/L of COD, respectively). Nonetheless, the equipment showed potential for water disinfection and organic matter reduction even without adding NaCl. Additionally, different mathematical models were assessed to account for microbial inactivation curves obtained from the electrochemical treatments.

[Nature-like swimming ponds and bathing: public health issues for congruous guidelines]. / Biopiscine e balneazione: considerazioni igienico sanitarie per lo sviluppo di adeguate linee guida.

Nature-like swimming ponds represent an emerging approach to recreational waters. The substitution of traditional disinfection with biodepuration enhances environmental sustainability, but implies relevant public health issues. No European regulations are available while several countries delivered local guidelines. Appropriate microbiological analysis, user education, and correct water management based on HACCP approach, represent key points for the development of future guidelines.

Effect of production variables on microbiological removal in locally-produced ceramic filters for household water treatment.

Diarrhoeal diseases cause an estimated 1.87 million child deaths per year. Point-of-use filtration using locally made ceramic filters improves microbiological quality of stored drinking water and prevents diarrhoeal disease. Scaling-up ceramic filtration is inhibited by lack of universal quality control standards. We investigated filter production variables to determine their affect on microbiological removal during 5-6 weeks of simulated normal use. Decreases in the clay:sawdust ratio and changes in the burnable decreased effectiveness of the filter. Method of silver application and shape of filter did not impact filter effectiveness. A maximum flow rate of 1.7 l(-hr) was established as a potential quality control measure for one particular filter to ensure 99% (2- log(10)) removal of total coliforms. Further research is indicated to determine additional production variables associated with filter effectiveness and develop standardized filter production procedures prior to scaling-up.

Microbiological effectiveness and cost of disinfecting water by boiling in semi-urban India.

Despite shortcomings, boiling is the most common means of treating water at home and the benchmark against which emerging point-of-use water treatment approaches are measured. In a 5-month study, we assessed the microbiological effectiveness and cost of the practice among 218 self-reported boilers relying on unprotected water supplies. Boiling was associated with a 99% reduction in geometric mean fecal coliforms (FCs; P < 0.001). Despite high levels of fecal contamination in source water, 59.6% of stored drinking water samples from self-reported boilers met the World Health Organization standard for safe drinking water (0 FC/100 mL), and 5.7% were between 1 and 10 FC/100 mL. Nevertheless, 40.4% of stored drinking water samples were positive for FCs, with 25.1% exceeding 100 FC/100 mL. The estimated monthly fuel cost for boiling was INR 43.8 (US$0.88) for households using liquid petroleum gas and INR 34.7 (US$0.69) for households using wood.

Surveillance for waterborne disease and outbreaks associated with recreational water use and other aquatic facility-associated health events--United States, 2005-2006.

PROBLEM/CONDITION: Since 1971, CDC, the U.S. Environmental Protection Agency, and the Council of State and Territorial Epidemiologists have collaboratively maintained the Waterborne Disease and Outbreak Surveillance System for collecting and reporting data related to waterborne-disease outbreaks (WBDOs) associated with drinking water. In 1978, WBDOs associated with recreational water (natural and treated water) were added. This system is the primary source of data regarding the scope and effects of disease associated with recreational water in the United States. In addition, data are collected on individual cases of recreational water-associated illnesses and infections and health events occurring at aquatic facilities but not directly related to water exposure. REPORTING PERIOD: Data presented summarize WBDOs and case reports associated with recreational water use that occurred during January 2005--December 2006 and previously unreported disease reports and outbreaks during 1978--2004. DESCRIPTION OF THE SYSTEM: Public health departments in the states, territories, localities, and the Freely Associated States (i.e., the Republic of the Marshall Islands, the Federated States of Micronesia, and the Republic of Palau, formerly parts of the U.S.-administered Trust Territory of the Pacific Islands) have primary responsibility for detecting, investigating, and voluntarily reporting WBDOs to CDC. Although the surveillance system includes data for WBDOs and cases associated with drinking water, recreational water, and water not intended for drinking, only cases and outbreaks associated with recreational water and health events at aquatic facilities are summarized in this report. RESULTS: During 2005--2006, a total of 78 WBDOs associated with recreational water were reported by 31 states. Illness occurred in 4,412 persons, resulting in 116 hospitalizations and five deaths. The median outbreak size was 13 persons (range: 2--2,307 persons). Of the 78 WBDOs, 48 (61.5%) were outbreaks of gastroenteritis that resulted from infectious agents or chemicals; 11 (14.1%) were outbreaks of acute respiratory illness; and 11 (14.1%) were outbreaks of dermatitis or other skin conditions. The remaining eight were outbreaks of leptospirosis (n = two), primary amebic meningoencephalitis (n = one), and mixed or other illnesses (n = five). WBDOs associated with gastroenteritis resulted in 4,015 (91.0%) of 4,412 illnesses. Fifty-eight (74.4%) WBDOs occurred at treated water venues, resulting in 4,167 (94.4%) cases of illness. The etiologic agent was confirmed in 62 (79.5%) of the 78 WBDOs, suspected in 12 (15.4%), and unidentified in four (5.1%). Thirty-four (43.6%) WBDOs had a parasitic etiology; 22 (28.2%), bacterial; four (5.1%), viral; and two (2.6%), chemical or toxin. Among the 48 gastroenteritis outbreaks, Cryptosporidium was confirmed as the causal agent in 31 (64.6%), and all except two of these outbreaks occurred in treated water venues where Cryptosporidium caused 82.9% (29/35) of the gastroenteritis outbreaks. Case reports associated with recreational water exposure that were discussed and analyzed separately from outbreaks include three fatal Naegleria cases and 189 Vibrio illnesses reported to the Cholera and Other Vibrio Illness Surveillance System. For Vibrio reporting, the most commonly reported species were Vibrio vulnificus, V. alginolyticus, and V. parahaemolyticus. V. vulnificus illnesses associated with recreational water exposure had the highest Vibrio illness hospitalization (77.6%) and mortality (22.4%) rates. In addition, 32 aquatic facility-related health events not associated with recreational water use (e.g., pool chemical mixing accidents) that occurred during 1983--2006 were received from New York. These events, which caused illness in 364 persons, are included in this report but analyzed separately. INTERPRETATIONS: The number of WBDOs summarized in this report and the trends in recreational water-associated disease and outbreaks demonstrate a substantial increase in number of reports from previous years. Outbreaks, especially the largest ones, occurred more frequently in the summer at treated water venues and caused gastrointestinal illness. Deficiencies leading to WBDOs included problems with water-quality, venue design, usage, and maintenance. Case reports of illness associated with recreational water use expand our understanding of the scope of waterborne illness by further underscoring the contribution of less well-recognized swimming venues (e.g., oceans) and illness (e.g., nongastrointestinal illness). Aquatic facilities are also a focus for injuries involving chemicals or equipment used routinely in the operation of swimming venues, thus illustrating the lack of training of some aquatics staff. PUBLIC HEALTH ACTIONS: CDC uses WBDO surveillance data to 1) identify the etiologic agents, types of aquatic venues, water-treatment systems, and deficiencies associated with outbreaks and case reports; 2) evaluate the adequacy of efforts (i.e., regulations and public awareness activities) to provide safe recreational water; 3) expand the scope of understanding about waterborne disease and health events associated with swimming and aquatics facilities; and 4) establish public health prevention priorities, data, and messaging that might lead to improved regulations, guidelines, and prevention measures at the local, state, and federal levels.

Assessment of potential aquatic herbicide impacts to California aquatic ecosystems.

A series of legal decisions culminated in 2002 with the California State Water Resources Control Board funding the San Francisco Estuary Institute to develop and implement a 3-year monitoring program to determine the potential environmental impacts of aquatic herbicide applications. The monitoring program was intended to investigate the behavior of all aquatic pesticides in use in California, to determine potential impacts in a wide range of water-body types receiving applications, and to help regulators determine where to direct future resources. A tiered monitoring approach was developed to achieve a balance between program goals and what was practically achievable within the project time and budget constraints. Water, sediment, and biota were collected under "worst-case" scenarios in close association with herbicide applications. Applications of acrolein, copper sulfate, chelated copper, diquat dibromide, glyphosate, fluridone, triclopyr, and 2,4-D were monitored. A range of chemical analyses, toxicity tests, and bioassessments were conducted. At each site, risk quotients were calculated to determine potential impacts. For sediment-partitioning herbicides, sediment quality triad analysis was performed. Worst-case scenario monitoring and special studies showed limited short-term and no long-term toxicity directly attributable to aquatic herbicide applications. Risk quotient calculations called for additional risk characterizations; these included limited assessments for glyphosate and fluridone and more extensive risk assessments for diquat dibromide, chelated copper products, and copper sulfate. Use of surfactants in conjunction with aquatic herbicides was positively associated with greater ecosystem impacts. Results therefore warrant full risk characterization for all adjuvant compounds.

Microbiological quality of indoor and outdoor swimming pools in Greece: investigation of the antibiotic resistance of the bacterial isolates.

During 1997-2005, the microbiological quality and susceptibility of bacterial isolates of swimming pool waters were investigated. A total of 462 water samples were collected from three indoor swimming pools (a teaching pool, a competition public pool, a hydrotherapy pool) and two outdoor swimming pools (a hotel semi-public and a residential private pool) in Northwestern Greece. All water samples were analyzed for the presence of bacteria, protozoa and fungi and susceptibility tests were performed for the bacterial isolates. Sixty-seven percent of the examined water samples conformed to the microbiological standards and 32.9% exceeded at least one of the indicated limits. Out of 107 bacterial isolates, 38 (35.5%) resistant strains were detected. Multi-resistant Pseudomonas alcaligenes, Leuconostoc, and Staphylococcus aureus (isolated from the teaching pool), Staphylococcus wernerii, Chryseobacterium indologenes and Ochrobactrum anthropi (isolated from the competition pool), Pseudomonas aeruginosa, P. fluorescens, Aeromonas hydrophila, Enterobacter cloacae, Klebsiella pneumoniae and S. aureus (isolated from the hydrotherapy pool) and A. hydrophila (isolated from the hotel pool) were detected. The swimming pool with the poorest microbiological quality (THC 500 cfu/ml in 12.1% of the samples, P. aeruginosa counts 1500 cfu/100 ml in 6% of the samples) and the highest prevalence of multi-resistant isolates (73.6%) was the hydrotherapy pool. No Cryptosporidium or Giardia cysts and no Legionella, Mycobacteria and Salmonella were detected, but there were isolations of Candida albicans, Aspergillus spp., Mucor spp., Alternaria spp., Rhizopus spp., Trichophyton spp., and Penicillium spp.

Comparative assessment of antimicrobial efficacy of new potential biocides for treatment of cooling and ballast waters.

The comparative in vitro antibacterial activity of five non-oxidizing biocides was investigated by laboratory standard test procedures. Minimum Inhibitory Concentrations (MIC) of two alkylated naphthoquinone derivative molecules (MNB and MPB) and three commercial biocide formulations (MACROTROL(R)MT200, MICROTREAT AQZ2010 and MICROBIOCIDE 2594) were determined against a total of 23 non-pathogenic bacterial strains. This investigation demonstrated a broad-spectrum bactericidal efficacy of three of the assayed biocides (MT200 and both naphthoquinone derivatives) at low use levels, also against naturally tolerant species, such as Pseudomonas spp. MT200 was the most effective, inhibiting bacterial growth of both Gram-positive (MIC<4 mg/l) and Gram-negative bacteria (MIC<16 mg/l), whereas effectiveness of naphthoquinones was highly variable (MIC ranging from 1 to 64 mg/l). The findings show the ability of the tested products to reduce bacterial populations under laboratory conditions. These products could provide an efficient bacterial growth control, for treatment of both fresh and salt waters used for various industrial purposes.

[Treatment of thermal pool waters]. / Il trattamento delle acque nelle piscine termali.

No laws currently exist regarding the treatment of spa pool water, since it is not completely logical that these should have the same requirements as normal swimming pools. The problem arises especially with regards to the use of chlorine as a disinfectant, which may actually annulate the therapeutic effects of spring waters by altering their physical-chemical characteristics. Possible choices may be represented by frequent replacement of pool water, which may be easily achievable for small pools but more difficult to implement for larger pools, or by alternative disinfection methods such as ozone or ultraviolet rays. The efficacy of these methods must be shown through frequent chemical and microbiological analyses and future, to be hoped-for laws or guidelines, will need to be aimed at defining safety performance standards rather than prescribing analytical intervention and control methods. Beyond the choice of disinfection method, it is extremely important to highlight some relevant hygienic measures that bathers should take and that play a fundamental role in preventing infectious diseases which may be acquired in pools. The most important of these include: showering before entering the pool, wearing slippers around the pool, not urinating in the pool, not bathing if affected by diarrhea, wearing a bathing cap, avoiding the use of contact lenses while bathing and avoiding exchanging towels. Pool managers have the important role of avoiding overcrowding of the facilities and ensuring that all technological systems function properly.

[Monitoring and control of opportunistic bacteria in a spa water used for aerosol hydrotherapy]. / Monitoraggio e controllo della contaminazione da batteri opportunisti in un'acqua termale erogata per aerosol e docce nasali.

A bicarbonate-sulphate-calcic water of a therapeutic spa was monitored for the presence of Legionella, Pseudomonas and Mycobacteria. The water was analysed by taking samples from the well, the feed tank and from the final aerosol generating devices of two different water lines, the former at 21-23 degrees, the second at 36-38 degrees. The bacteria in question were always absent from the well. Legionellae were found in the water of aerosol equipment: Legionella micdadei was isolated from 75% of samples, L. bozemanii from 75% and 50% (respectively 36-38 degrees and 21-22 degrees water lines) and other species of environmental Legionellae from 25% of samples. The water of aerosol equipment presented high total bacterial counts (10(3)-10(4) cfu/ml) and exspecially high concentrations of Pseudomonadaceae (10(2)-10(3) cfu/100 ml). These bacteria, unlike the Legionellae, were also isolated from the feed tank at mean concentrations of about 10(2) cfu/100 ml. Mycobacteria were found in 75 and 50% of samples collected from final devices, respectively from the heated and not heated water lines. The isolates were M. gordonae (85% of isolates) and M. fortuitum (15%), but at concentrations very low. Both treatments with sodium hypochlorite (20 ppm of residual chlorine) and peracetic acid (20 ppm) resulted in the reduction of total bacterial counts and elimination of Pseudomonas from the water in the tank, but not in elimination of Pseudomonas and Legionellae from the nebulizers. The disinfectants were evidently not able to efficiently reach all the points where Pseudomonas and Legionella had settled and grown. In order to obtain total abatement it was necessary to carry out a radical restructuring of the plant, involving the replacement of the old nebulizer benches with new aerosol equipment that could be subjected to a new system of programmed thermal shock.

Surveillance data from public spa inspections--United States, May-September 2002.

Approximately 5 million public and private hot tubs, whirlpools, and spas are used in the United States. Extensive spa use combined with inadequate maintenance contribute to recreational water illnesses (RWIs) caused by pathogens such as Pseudomonas spp., Legionella spp., and Mycobacterium spp. In the United States, local environmental health inspectors periodically inspect public spas to determine their compliance with local or state health regulations. During inspections for regulatory compliance, data pertaining to spa water chemistry, filtration and recirculation, and management and operations are collected. This report summarizes spa inspection data from six sites in the United States during May 1-September 1, 2002. The findings underscore the utility of these data for public health decision-making and the need for increased training and vigilance by operators to ensure high-quality spa water for use by the public.

Evaluation of microbiological and physicochemical indicators for wastewater treatment.

The quality control of wastewater treatments was monitored using selected novel and classical physicochemical and microbiological indicators, and the associations of the treatments with the effluents was analyzed. The microbiological indicators monitored were heterotrophic plate count (HPC), total coliforms (TC), fecal coliforms (FC), fecal streptococci (FS), sulfite-reducing clostridia (SRC), Pseudomonas aeruginosa, and Salmonella spp. The stages of wastewater treatment also were evaluated through determination of ammonia; biological oxygen demand (BOD(5)); chemical oxygen demand (COD); chloride; conductivity; suspended dissolved and total solids; fats; nitrate, nitrite, and total nitrogen; pH; phosphate and total phosphorus. Additional indicators included the Escherichia coli growth inhibition (IGEC) bioassay for assessing whole effluent toxicity, spectral determinations between wavelengths (lambda) 190-650 nm, and total (TP) and soluble (SP) protein contents. Of the more common physicochemical parameters, only BOD(5), COD, suspended and total solids, and fats showed a statistically significant reduction between raw water and effluent; for the microbiological indicators, significant reduction was seen only for HPC, FC, and Ps. aeruginosa. We suggest that determinations of Ps. aeruginosa be commonly used as an indicator of wastewater quality. Spectral analysis--most notably the values of absorbance at 225, 255, and 295 nm-revealed a statistically significant correlation with several physicochemical parameters. Statistical analysis of SP and TP values showed them to be good indicators of contamination. The quantitative study of Salmonella spp. and the results of the IGEC bioassay show the need for close control of infectious and toxic risks in wastewater and effluents.

The development and evaluation of ultrasound for the treatment of bacterial suspensions. A study of frequency, power and sonication time on cultured Bacillus species.

Some species of bacteria produce colonies and spores which agglomerate in spherical clusters (Bacillus subtilis) and this serves as a protection for the organisms inside against biocidal attack. Flocs of fine particles e.g. clay can entrap bacteria which can also protect them against the biocides. It is because of problems such as these that alternative methods of disinfecting water are under active investigation. One such method is the use of power ultrasound, either alone or in combination with other methods. Ultrasound is able to inactivate bacteria and deagglomerate bacterial clusters or flocs through a number of physical, mechanical and chemical effects arising from acoustic cavitation. The aim of this study was to investigate the effect of power ultrasound at different powers and frequencies on Bacillus subtilis. Viable plate count techniques were used as a measure of microbial activity. Results showed a significant increase in percent kill for Bacillus species with increasing duration of exposure and intensity of ultrasound in the low-kilohertz range (20 and 38 kHz). Results obtained at two higher frequencies (512 and 850 kHz) indicated a significant increase in bacteria count suggesting declumping. In assessing the bacterial kill with time under different sonication regimes three types of behaviour were characterized: High power ultrasound (lower frequencies) in low volumes of bacterial suspension results in a continuous reduction in bacterial cell numbers i.e. the kill rate predominates. High power ultrasound (lower frequencies) in larger volumes results in an initial rise in cell numbers suggesting declumping of the bacteria but this initial rise then falls as the declumping finishes and the kill rate becomes more important. Low intensity ultrasound (higher frequencies) gives an initial rise in cell numbers as a result of declumping. The kill rate is low and so there is no significant subsequent decrease in bacterial cell numbers.

Bioremediation of chlorate or perchlorate contaminated water using permeable barriers containing vegetable oil.

A scale model of an in situ permeable barrier, formed by injecting vegetable oil onto laboratory soil columns, was used to remove chlorate and perchlorate from flowing groundwater. The hypothesis that trapped oil would serve as a substrate enabling native microorganisms to reduce chlorate or perchlorate to chloride as water flowed through the oil-rich zone had merit. Approximately 96% of the 0.2 mM chlorate and 99% of the 0.2 mM perchlorate present in the water was removed as water was pumped through columns containing vegetable oil barriers. The product formed was chloride. When nitrate at 1.4 mM was added to the water, both nitrate and chlorate were removed. High concentrations of chlorate or perchlorate can be treated; 24 m M chlorate and 6 mM perchlorate were completely reduced to chloride during microcosm incubations. Microorganisms capable of reducing perchlorate are plentiful in the environment.

Incidence of Pseudomonas aeruginosa in recreational and hydrotherapy pools.

Pseudomonas aeruginosa remains an important agent of opportunistic infection in patients, particularly those with respiratory complications and burns. One natural niche of this organism is water and water-associated facilities, hence the aim of this study was to examine specimens from recreational and hydrotherapy pools in Northern Ireland over a two-year period. Water specimens (n = 3,510) were obtained from three amenity categories, namely, 13 hydrotherapy pools (specimen number [n] = 323), 51 Jacuzzis/spas (n = 1,397) and 68 swimming pools (n = 1,790). Specimens (100 ml) were filtered through a cellulose acetate (0.45 micron pore size) gridded filter and the membrane was placed on Pseudomonas CFC agar (Oxoid CM559 + SR103) and incubated at 37 degrees C for 48 +/- 2 h. Colonies that clearly showed pyocyanin production or met other identification criteria were considered P. aeruginosa. Of the amenities examined 4/13 hydrotherapy pools (30.8%), 37/51 Jacuzzis/spas (72.5%) and 26/68 swimming pools (38.2%) were positive for P. aeruginosa. The most heavily contaminated amenity category was the Jacuzzi/spa, where 34.7% and 12% of private and public sites respectively were positive for P. aeruginosa at a level of greater than 1,000 cfu 100 ml-1. Approximately twice as many samples were positive in private Jacuzzis/spas compared to publicly operated facilities. There was a similar trend with respect to public and private hydrotherapy pools, though bacterial counts did not exceed 1,000 cfu 100 ml-1. Recreational and therapeutic amenities involving the use of water may be a potential source of P. aeruginosa for susceptible patient groups, including patients with cystic fibrosis and bronchiectasis. This may vary depending on amenity type and public/private ownership of such amenities.

Survey of Staphylococcus aureus contamination in a hospital's spa and hydrotherapy pools.

Twenty-seven percent of water samples taken from one spa and two hydrotherapy pools in one Welsh hospital over three months contained Staphylococcus aureus. Four per cent of samples were deemed unacceptable because they contained coliforms, E. coli or Pseudomonas aeruginosa. Aerobic colony counts varied between samples but no counts were > 100 cfu/ml. Disinfection and pH records indicated no significant problems with pool maintenance over the sampling period, and bather loads were generally low. Some samples positive for S. aureus were found after lengthy periods of pool inactivity, indicating persistence of the organism.