Evaluation of susceptibility of polymer and rubber materials intended into contact with drinking water on biofilm formation

Background: Plumbing materials in water distribution networks and indoor installations are constantly evolving. The application of new, more economical solutions with plastic materials eliminates the corrosion problems, however, do not fully protect the consumer against secondary microbial contamination of water intended for human consumption caused by the presence of a biofilm on the inner surface of materials applied. National Institute of Public Health - National Institute of Hygiene conducts research aimed at a comprehensive assessment of this type of materials, resulting their further marketing authorization in Poland. Objectives: Evaluation and comparison of polymer and rubber materials intended to contact with water for the susceptibility to biofilm formation. Materials and Methods: Plastic materials (polyethylene, polypropylene, polyvinyl chloride) and rubber compounds (EPDM, NBR), from different manufacturers were evaluated. The study was carried out on 37 samples, which were divided into groups according to the material of which they were made. The testing was conducted according to the method based on conditions of dynamic flow of tap water. The level of bioluminescence in swabs taken from the surface of the tested materials was investigated with a luminometer. Results: Evaluation of plastic materials does not show major objections in terms of hygienic assessment. All materials met the evaluation criteria established for methodology used. In case of rubber compounds, a substantial part clearly exceeded the limit values, which resulted in their negative assessment and elimination of these materials from domestic market. Conclusions: High susceptibility to the formation of biofilm in the group of products made of rubber compounds has been demonstrated. Examined plastic materials, except for several cases, do not revealed susceptibility to biofilm formation, but application of plastics for distribution of water intended for human consumption does not fully protect water from secondary, microbiological contamination. Complete verification of plumbing materials including biofilm formation test before their introduction into the domestic market should be continued.

[Occurrence of Legionella in technological water and studies of the total number of bacteria and fungi in indoor air at workplaces where water aerosol is generated]. / Wystepowanie bakterii z rodzaju Legionella w wodzie technologicznej oraz badania ogólnej liczby bakterii i grzybów powietrzu na stanowiskach pracy, na których generowany jest aerozol wodny.

BACKGROUND: The aim of the study was to confirm the fact that technological water is a significant carrier of Legionella, a potential serious threat to the health of operators of mechanical devices generating contaminated water aerosol. MATERIAL AND METHODS: Microbiological analyses of water and indoor air were conducted in 8 different production facilities involved in mechanical processing of glass. The study covered 81 samples of water collected from technical water systems. Isolation of Legionella and the determination of total number of microorganisms were processed according to PN-EN ISO 11731-2:2008E and PN-EN ISO 6222:2004P, respectively. Air samples were collected using air samplers and total numbers of bacteria and fungi were determined. RESULTS: The studies of process water, indicated the presence of Legionella in 27.2% of collected samples. These bacteria were present in both closed and open process water reservoirs at 10 cfu/100 ml to 2.9 x 10(4) cfu/100 ml. The count of other associated bacteria exceeded 10(3) cfu/ml. All strains isolated from Legionella-positive samples were identified as L. pneumophila SG 2-14. In 5 of 8 studied production facilities an increased total number of aerial bacteria and fungi was observed in samples collected in close vicinity of aerosol source. CONCLUSIONS: To reduce the number of microorganisms in water it is required to introduce technological water quality monitoring and procedures for the cleaning and disinfecting of mechanical devices generating water aerosol.

[Respiratory symptoms among industrial workers exposed to water aerosol. A pilot study of process water and air microbial quality]. / Analiza wystepowania dolegliwosci i objawów ze strony ukladu oddechowego u osób zatrudnionych w przemysle na stanowiskach pracy generujacych aerozol wodny. Badania pilotazowe jakosci mikrobiologicznej powietrza i wody technologicznej.

BACKGROUND: The frequency of respiratory symptoms in workers exposed to water aerosol was evaluated along with the preliminary assessment of microbiological contamination of air and water used in glass processing plants. MATERIAL AND METHODS: A questionnaire survey was conducted in 131 workers from 9 glass processing plants. Questions focused on working conditions, respiratory symptoms and smoking habits. A pilot study of air and water microbiological contamination in one glass processing plant was performed. Water samples were tested for Legionella in accordance with EN ISO 11731-2:2008 and for total colony count according to PN-EN ISO 6222:2004. Air samples were tested for total numbers of molds and mildews. RESULTS: During the year preceding the survey acute respiratory symptoms occurred in 28.2% of participants, while chronic symptoms were reported by 29% of respondents. Increased risks of cough and acute symptoms suggestive of pneumonia were found among the respondents working at a distance up to 20 m from the source of water aerosol compared to other workers (OR = 2.7), with no difference in the frequency of other symptoms. A microbiological analysis of water samples from selected glass plant revealed the presence of L. pneumophila, exceeding 1000 cfu/100 ml. The number of bacteria and fungi detected in air samples (above 1000 cfu/m3) suggested that water aerosol at workplaces can be one of the sources of the air microbial contamination. CONCLUSIONS: The questionnaire survey revealed an increased risk of cough and acute symptoms suggestive of pneumonia in the group working at a shortest distance form the source of water aerosol.

[Optimization of Cryptosporidium and Giardia detection in water environment using automatic elution station Filta-Max xpress]. / Optymalizacja metody wykrywania pierwotniaków pasozytniczych Cryptosporidium i Giardia w srodowisku wodnym przy zastosowaniu automatycznej stacji pluczacej Filta-Max xpress.

BACKGROUND: The presence of parasitic protozoa in drinking water is mostly a result of improperly maintened the water treatment process. Currently, in Poland the testing of Cryptosporidium and Giardia in water as a part of routine monitoring of water is not perform. OBJECTIVE: The aim of this study was the optimization of the method of Cryptosporidium and Giardia detection in water according to the main principles of standard ISO 15553:2006 and using Filta-Max xpress automatic elution station. MATERIAL AND METHOD: Preliminary tests were performed on the samples contaminated with oocysts and cysts of reference strains of both parasitic protozoa. Further studies were carried out on environmental samples of surface water sampled directly from the intakes of water (21 samples from Vistula River and 8 samples from Zegrzynski Lake). Filtration process and samples volume reducing were performed using an automatic elution system Filta-Max xpress. Next, samples were purified during immunomagnetic separation process (IMS). Isolated cysts and oocysts were stained with FITC and DAPI and than the microscopic observation using an epifluorescence microscope was carried out. RESULTS: Recovery of parasite protozoa in all contaminated water samples after 9-cycles elution process applied was mean 60.6% for Cryptosporidium oocysts and 36.1% for Giardia cysts. Studies on the environmental surface water samples showed the presence of both parasitic protozoa. Number of detected Giardia cysts ranged from 1.0/10 L up to 4.5/10 L in samples from Zegrzynski Lake and from 1.0/10 L up to 38.9/10 L in samples from Vistula River. Cryptosporidium oocysts were present in 50% of samples from the Zegrzynski Lake and in 47.6% of samples from the Vistula River, and their number in both cases was similar and ranged from 0.5 up to 2.5 oocyst/10 L. The results show that applied procedure is appropriate for detection the presence of parasitic protosoan in water, but when water contains much amount of inorganic matter and suspended solids test method have to be modified like subsamples preparation and filtration process speed reduction. CONCLUSIONS: The applied method with the modification using Filta-Max xpress system can be useful for the routine monitoring of water. Detection of Cryptosporidium and Giardia in all samples of water taken from the intakes of surface water shows the possibility oftransfering of the protozoan cysts into the water intended for the consumption, therefore the testing of Cryptosporidium and Giardia should be included into the monitoring of water.

[Microbiological quality of hospital indoor air. Determinant factors for microbial concentration in air of operating theatres]. / Czystosc mikrobiologiczna powietrza w szpitalu. Czynniki wplywajace na stezenie mikroorganizmów w powietrzu sal operacyjnych.

Foregoing research presents results of total number of bacteria and fungi assays carried out in air of operating theatres before, during and directly after planned surgical procedure. Basing on the results obtained in winter and summer the assessment of bacteria and fungi concentration in atmospheric air impact on microbial quality of air inside of operating theatre was elaborated. Investigation of the reason of high concentration of bacteria in air inside of operating rooms was conducted simultaneously. Presented results of microbial air purity collected from atmospheric air in parallel with indoor air demonstrated that air filters applied in air-conditioning system worked correctly and bacterial contamination of air had different reasons.

[Microbiological quality of indoor air in dentist's offices]. / Czystosc mikrobiologiczna powietrza w gabinetach dentystycznych.

It's a well-known fact that water-air aerosol can be a result of some dentist's activity during regular dental surgery and can contain broad range of microorganisms from dental plaque, saliva and pus. Assessment of dentist's activity impact on bacteria concentration in air of dentist surgery was a main purpose of this assay. Presented data contains results of four total number of bacteria and fungi in air assays made with fifty minutes intervals. Air samples was taken in dentist's office during regular dental surgery of patients afflicted with oral cavity infection with pus. Due to defective ventilation system, bacteria's concentration in air samples increased from less than thousand cfu/m3 to almost three thousands cfu/m3. Obtained results demonstrated that aerosol containing bacteria is released during regular dental surgery so the concentration of potentially infectious bacteria around patient and dentist can increase up to three thousands cfu/m3.

[Microbial air purity in hospitals. Operating theatres with air conditioning system]. / Czystosc mikrobiologiczna powietrza w szpitalach. Sale operacyjne klimatyzowane.

The aim of this study was to show the influence of air conditioning control for microbial contamination of air inside the operating theatres equipped with correctly working air-conditioning system. This work was based on the results of bacteria and fungi concentration in hospital air obtained since 2001. Assays of microbial air purity conducted on atmospheric air in parallel with indoor air demonstrated that air filters applied in air-conditioning systems worked correctly in every case. To show the problem of fluctuation of bacteria concentration more precisely, every sequences of single results from successive measure series were examined independently.

Assessment of microbial growth on the surface of materials in contact with water intended for human consumption using ATP method.

Elaboration of an assessment method for plumbing materials contacting drinking water was the main purpose of this study. The investigation was conducted in 8 week cycles in dynamic conditions using a continuous flow reactor. Microbial growth was measured indirectly by a bioluminescence technique (ATP assay). Every week swabs from the surface of tested materials (polypropylene and different types of polyethylene), from the domestic market were collected and the level of bioluminescence was examined. The results obtained from the surface of tested materials were repeatable and clearly approximated those obtained from the surface of a negative control (stainless steel, low susceptibility for microbial growth). The level of bioluminescence (ATP) on the surface of positive control (paraffin, high susceptibility for microbial growth) was many times higher than that observed on other materials. The presented investigation was the main part of a validation process, which in short time will serve to initiate a complete assessment system for organic materials contacting drinking water.

[Investigation of susceptibility of materials contacting with drinking water for microbial growth]. / Badania podatnosci materialów kontaktujacych sie z woda przeznaczona do spozycia na powstawanie obrostów mikrobiologicznych.

Main purpose of this paper was to confirm of results obtained by new method based on bioluminescence technique for determination of susceptibility of materials contacting with drinking water were repeatable. Investigation was conducted during 8 weeks in dynamic conditions using continuous flow reactor UPE. Every week swabbes from tested materials were collected and level of ATP was examined. The results obtained from the surface of tested materials were repeatable and clearly approximate to those obtained from the surface of negative control material (stainless steel, low susceptibility for microbial growth). The level of the ATP on the surface of positive control material (paraffin, large susceptibility for microbial growth) was fifty times higher than that observed on other materials. Presented investigation was the main part of validation process, which in short time will serve to initiate system of complete assessment for materials contacting with drinking water according to Council Directives 89/106/EEC and 98/83/EC requirements.

[Elaboration of the method for assessment of susceptibility to microbial growth of materials contacting with drinking water]. / Opracowanie metody oceny podatnosci materialów kontaktujacych sie z woda przeznaczona do spozycia na powstawanie obrostów mikrobiologicznych.

Initial methodological study was conducted to determine the susceptibility to microbial growth of different materials applied in contact with drinking water. The purpose of this assay was to elaborate the method for determining the ability of different materials contacting with drinking water to promote microbial growth and to determine possible correlation of results obtained by two analytic methods: inoculation of microorganisms swabbed from materials surface into a medium and ATP level examination. The assay was conducted during 16 weeks in dynamic conditions using continuous flow reactor. Every two weeks swabbes from examinated materials were collected and the total number of microorganisms was determined after incubation in 22 degrees C for 72 hours and in 37 degrees C for 48 hours respectively. Determination of microorganisms number and ATP level were both examinated in water inlet. Difference in susceptibility to microbial growth of different materials used in contact with drinking water was observed. This was confirmed by both analytic methods. Microbial growth on the surface of negative control materials (glass, poliethylene and stainless steel) was several time less intensive than on positive control material (floor finish not destined for contact with drinking water). Correlation between the quantity of microorganisms and ATP level on the surface of the same kind of materials was confirmed. Usefulness of continous flow reactor was confirmed.

[Biofilm--short characteristic of microbial growth related to drinking water distribution systems]. / Biofilm--krótka charakterystyka obrostów mikrobiologicznych zwiazanych z instalacjami wody przeznaczonej do spozycia przez ludzi.

General information about drinking water biofilms containing few steps biofilm forming process, microorganisms' short characterization and potential risk related to microbial presence in water installations has been presented. A part of review concerns European Acceptance Scheme (EAS) basis and current methods applied for assessment of susceptibility of materials contacting with drinking water to microbial growth.