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Sample records for premilking teat disinfectant

  1. Effect of disinfecting teats post-milking or pre- and post-milking on intramammary infection and somatic cell count.

    Science.gov (United States)

    Williamson, J H; Lacy-Hulbert, S J

    2013-09-01

    To determine the effects of (a) post-milking teat disinfection compared with no disinfection and (b) pre- and post-milking teat disinfection compared with post-milking disinfection alone, on the incidence of new intramammary infection (IMI), somatic cell count (SCC) and teat skin abnormalities in dairy cows. In Experiment 1, dairy cows in five dairy herds were randomly allocated to a post-milking teat disinfection group (n=230), that was sprayed with an iodine-based disinfectant (TeatguardPlus) for a complete lactation, or to a non-disinfected group (n=239). In Experiment 2, cows were randomly allocated to post-milking teat disinfection (n=239) or both pre- and post-milking teat disinfection (n=235), using a chloramine-T-based disinfectant (Teatsweet) for both treatments, from calving to 118-127 days in milk. The incidence of new IMI was determined by aseptic sampling of all quarters at calving, during lactation, and at trial end or at drying-off, with clinical mastitis cases sampled on detection. SCC and teat skin abnormalities were measured at 2-monthly intervals during lactation. In both experiments, disinfectant was applied by spray application. Cows that received post-milking teat disinfection had a lower incidence of new IMI caused by Staphylococcus aureus, Streptococcus uberis, Corynebacterium spp and coagulase negative staphylococci, had lower bulk milk SCC during lactation, and had fewer teat skin abnormalities compared with the non-disinfected cows (p disinfection, in addition to post-milking teat disinfection, did not reduce the incidence of new IMI for any pathogens and did not reduce SCC (p> 0.05). Post-milking teat disinfection applied as a spray is a key component in mastitis control in New Zealand. There was no benefit from the addition of pre-milking disinfection. This study confirms previous findings of the effectiveness of post-milking teat disinfection in reducing the incidence of IMI caused by the common mastitis-causing pathogens in New

  2. Anatomical characteristics of teats and premilking bacterial counts of teat skin swabs of primiparous cows exposed to different types of bedding.

    Science.gov (United States)

    Guarín, J F; Baumberger, C; Ruegg, P L

    2017-02-01

    Bacterial populations of teat skin are associated with risk of intramammary infection and may be influenced by anatomical characteristics of teats. The objective of this study was to evaluate associations of selected anatomical characteristics of teats with bacterial counts of teat skin of cows exposed to different types of bedding. Primarily primiparous Holstein cows (n = 128) were randomly allocated to 4 pens within a single barn. Each pen contained 1 type of bedding [new sand (NES), recycled sand (RS), deep-bedded manure solids (DBMS), and shallow-bedded manure solids over foam core mattresses (SBMS)]. During a single farm visit udders (n = 112) were scored for hygiene and 1 front (n = 112) and 1 rear teat (n = 111) of each enrolled cow were scored for hyperkeratosis (HK). Teat length, teat barrel diameter, and teat apex diameter were measured and teat skin swabs were systematically collected for microbiological analysis. Linear type evaluation data for udders of each cow were retrieved for each cow. Teat position (front or rear) was associated with occurrence of clinical mastitis during the 12 mo before the farm visit and more cases occurred in front quarters. The proportion of udders that were classified as clean (score 1 or 2) was 68, 82, 54, and 95% for cows housed in pens containing NES, RS, SBMS, and DBMS, respectively. No association was found between HK score and teat position and no association was found between HK score and teat skin bacterial count. Bacterial counts of teat skin swabs from front teats of cows in pens containing RS and SBMS were significantly less than those of rear teats of cows in pens containing DBMS or NES. Teat skin bacterial counts were significantly greater for swabs obtained from teats of cows with udder hygiene scores of 3 and 4 as compared with swabs obtained from cows with cleaner udders. Of all udder conformation traits evaluated, only narrower rear teat placement was positively associated with bacterial counts on teat skin

  3. A Novel Lactobacilli-Based Teat Disinfectant for Improving Bacterial Communities in the Milks of Cow Teats with Subclinical Mastitis

    Directory of Open Access Journals (Sweden)

    Jie Yu

    2017-09-01

    Full Text Available Teat disinfection pre- and post-milking is important for the overall health and hygiene of dairy cows. The objective of this study was to evaluate the efficacy of a novel probiotic lactobacilli-based teat disinfectant based on changes in somatic cell count (SCC and profiling of the bacterial community. A total of 69 raw milk samples were obtained from eleven Holstein-Friesian dairy cows over 12 days of teat dipping in China. Single molecule, real-time sequencing technology (SMRT was employed to profile changes in the bacterial community during the cleaning protocol and to compare the efficacy of probiotic lactic acid bacteria (LAB and commercial teat disinfectants. The SCC gradually decreased following the cleaning protocol and the SCC of the LAB group was slightly lower than that of the commercial disinfectant (CD group. Our SMRT sequencing results indicate that raw milk from both the LAB and CD groups contained diverse microbial populations that changed over the course of the cleaning protocol. The relative abundances of some species were significantly changed during the cleaning process, which may explain the observed bacterial community differences. Collectively, these results suggest that the LAB disinfectant could reduce mastitis-associated bacteria and improve the microbial environment of the cow teat. It could be used as an alternative to chemical pre- and post-milking teat disinfectants to maintain healthy teats and udders. In addition, the Pacific Biosciences SMRT sequencing with the full-length 16S ribosomal RNA gene was shown to be a powerful tool for monitoring changes in the bacterial population during the cleaning protocol.

  4. Iodide Residues in Milk Vary between Iodine-Based Teat Disinfectants

    NARCIS (Netherlands)

    French, Elizabeth A; Mukai, Motoko; Zurakowski, Michael; Rauch, Bradley; Gioia, Gloria; Hillebrandt, Joseph R; Henderson, Mark; Schukken, Ynte H; Hemling, Thomas C

    Majority of iodine found in dairy milk comes from the diet and teat disinfection products used during milking process. The objective of this study was to evaluate the effects of 4 iodine-based teat dips on milk iodide concentrations varying in iodine level (0.25% vs. 0.5%, w/w), normal low viscosity

  5. Defining standardized protocols for determining the efficacy of a postmilking teat disinfectant following experimental exposure of teats to mastitis pathogens.

    Science.gov (United States)

    Schukken, Y H; Rauch, B J; Morelli, J

    2013-04-01

    The objective of this paper was to define standardized protocols for determining the efficacy of a postmilking teat disinfectant following experimental exposure of teats to both Staphylococcus aureus and Streptococcus agalactiae. The standardized protocols describe the selection of cows and herds and define the critical points in performing experimental exposure, performing bacterial culture, evaluating the culture results, and finally performing statistical analyses and reporting of the results. The protocols define both negative control and positive control trials. For negative control trials, the protocol states that an efficacy of reducing new intramammary infections (IMI) of at least 40% is required for a teat disinfectant to be considered effective. For positive control trials, noninferiority to a control disinfectant with a published efficacy of reducing new IMI of at least 70% is required. Sample sizes for both negative and positive control trials are calculated. Positive control trials are expected to require a large trial size. Statistical analysis methods are defined and, in the proposed methods, the rate of IMI may be analyzed using generalized linear mixed models. The efficacy of the test product can be evaluated while controlling for important covariates and confounders in the trial. Finally, standards for reporting are defined and reporting considerations are discussed. The use of the defined protocol is shown through presentation of the results of a recent trial of a test product against a negative control. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  6. Reduction of teat skin mastitis pathogen loads: differences between strains, dips, and contact times.

    Science.gov (United States)

    Enger, B D; Fox, L K; Gay, J M; Johnson, K A

    2015-02-01

    The purpose of these experiments was to (1) assess differences in mastitis pathogen strain sensitivities to teat disinfectants (teat dips), and (2) determine the optimum time for premilking teat dips to remain in contact with teat skin to reduce pathogen loads on teat skin. Two experiments were conducted using the excised teat model. In experiment 1, the differences in mastitis pathogen strain sensitivities to 4 commercially available dips (dip A: 1% H2O2; dip B: 1% chlorine dioxide; dip C: 1% iodophor; and dip D: 0.5% iodophor) were evaluated. Four strains of 11 common mastitis pathogens (Staphylococcus aureus, Streptococcus agalactiae, Mycoplasma bovis, Streptococcus dysgalactiae, Streptococcus uberis, Escherichia coli, Staphylococcus chromogenes, Staphylococcus epidermidis, Staphylococcus hyicus, Staphylococcus xylosus, and Staphylococcus haemolyticus) were tested. In experiment 2, the percentage log reduction of mastitis pathogens (Escherichia coli, Streptococcus uberis, Streptococcus dysgalactiae, Klebsiella species, Staphylococcus chromogenes, Staphylococcus haemolyticus, Staphylococcus xylosus, and Staphylococcus epidermidis) on teat skin with 3 commercially available teat dips: dip A; dip D; and dip E: 0.25% iodophor, using dip contact times of 15, 30, and 45 s, was evaluated. Experiment 1 results indicated significant differences in strain sensitivities to dips within pathogen species: Staphylococcus aureus, Staphylococcus chromogenes, and Streptococcus uberis. Species differences were also found where Mycoplasma bovis (97.9% log reduction) was the most sensitive to tested teat dips and Staphylococcus haemolyticus (71.4% log reduction) the most resistant. Experiment 2 results indicated that contact times of 30 and 45 s were equally effective in reducing recovered bacteria for dips D and E and were also significantly more effective than a 15-s contact time. No differences were seen in recovered bacteria between tested contact times after treatment with dip

  7. Efficacy of a high free iodine barrier teat disinfectant for the prevention of naturally occurring new intramammary infections and clinical mastitis in dairy cows.

    Science.gov (United States)

    Martins, C M M R; Pinheiro, E S C; Gentilini, M; Benavides, M Lopez; Santos, M V

    2017-05-01

    Using a natural exposure trial design, the goal of our study was to evaluate the clinical efficacy of an iodine teat disinfectant with barrier properties and a high level of free iodine relative to a conventional iodine teat disinfectant with no barrier properties and low levels of free iodine. During the 18 wk of the trial, quarter milk samples were collected every 2 wk from 385 dairy cows from 2 herds. Cows on both farms were assigned in a balanced way according to milk yield, number of lactation, days in milk, somatic cell count (SCC) and microbiology culture pretrial into one of following groups: nonbarrier post milking teat disinfectant (NBAR; n = 195 cows; 747 quarters) or barrier postmilking teat disinfectant (BAR; n = 190 cows; 728 quarters). Afterward, at each scoring date every 2 wk, milk SCC was quantified in samples from all mammary quarters and microbiologic culture was only performed on milk samples with SCC >200,000 cells/mL for multiparous cows and SCC >100,000 cells/mL for primiparous cows. A new intramammary infection (NIMI) was defined when a quarter had milk SCC 200,000 cells/mL for multiparous cows and >100,000 cells/mL for primiparous cows, and positive microorganism isolation. A quarter could have several NIMI, but only 1 case per specific pathogen was considered. The most frequently isolated microorganism group on both farms was Streptococcus spp. (6.25% of total mammary quarters), followed by coagulase-negative staphylococci (3.6%) and Corynebacterium spp. (1.5%). In the present study, an interaction occurred between treatment and week of trial on the incidence risk of NIMI. Quarters disinfected with BAR had 54 and 37% lower odds of NIMI than quarters disinfected with NBAR at 8 and 16 wk of the trial, respectively; whereas at other weeks of the study both products had similar incidence risks of NIMI. Overall, teats disinfected with BAR had 46% lower odds of acquiring a clinical mastitis than those disinfected with NBAR. We concluded that

  8. An observational study investigating the association of ultrasonographically assessed machine milking-induced changes in teat condition and teat-end shape in dairy cows.

    Science.gov (United States)

    Wieland, M; Virkler, P D; Borkowski, A H; Älveby, N; Wood, P; Nydam, D V

    2018-06-21

    Mechanical forces during machine milking induce changes in teat condition which can be differentiated into short-term and long-term changes. Machine milking-induced short-term changes in teat condition (STC) are defined as tissue responses to a single milking and have been associated with the risk of new intramammary infection. Albeit, their association with teat characteristics, such as teat-end shape, has not been investigated by rigorous methods. The primary objective was to determine the association of STC, as measured by ultrasonography, with teat-end shape. The second objective was to describe possible differences in the recovery time of teat tissue after machine milking among teats with different teat-end shapes. Holstein cows (n=128) were enrolled in an observational study, housed in free-stall pens with sand bedding and milked three times a day. Ultrasonography of the left front and right hind teat was performed after teat preparation before milking (t-1), immediately after milking (t 0) and 1, 3, 5 and 7 h after milking (t 1, t 3, t 5, t 7). The teat tissue parameters measured from ultrasound scans were teat canal length, teat-end diameter, teat-end diameter at the midpoint between the distal and proximal end of the teat canal, teat wall thickness, and teat cistern width. Teat-end shape was assessed visually and classified into three categories: pointed, flat and round. Multivariable linear regression analyses showed differences in the relative change of teat tissue parameters (compared with t-1) at t 0 among teats with different teat-end shapes, with most parameters showing the largest change for round teats. The premilking values were reached (recovery time) after 7 h in teats with a pointed teat-end shape, whereas recovery time was greater than 7 h in teats with flat and round teat-end shapes. Under the same liner and milking machine conditions, teats with a round teat-end shape had the most severe short-term changes. The results of this observational

  9. Teat condition in dairy cows

    NARCIS (Netherlands)

    Neijenhuis, Francesca

    2004-01-01

    The dairy cow's teat is the first line of defence against mastitis pathogens. The milking process may affect the teat's condition, increasing the risk of mastitis. It is well-proven that teat-ends with severe erosions or broken skin will have an increased risk of mastitis. However, more common

  10. Teat Condition in Dairy Cows

    NARCIS (Netherlands)

    Neijenhuis, F.

    2004-01-01

    The dairy cow's teat is the first line of defence against mastitis pathogens. The milking process may affect the teat's condition, increasing the risk of mastitis. It is well-proven that teat-ends with severe erosions or broken skin will have an increased risk of mastitis. However, more common

  11. Disinfectant effect of Methylated Ethanol against Listeria species

    OpenAIRE

    Y Yakubu; M D Salihu; O O Faleke; M B Abubakar; A A Magaji,A U Junaidu

    2012-01-01

    This study was carried out in order to determine the disinfectant effect of Methylated spirit® (95% methanol and 5% ethanol) as a teat dip against Listeria species. Hand milking was employed to collect 576 (288 x 2) raw milk samples from different lactating cows within Sokoto metropolis (Nigeria). 288 samples were collected before disinfecting the udder teats with Methylated spirit®, while the other 288 were collected after disinfection with Methylated spirit®. The ...

  12. Disinfectant effect of Methylated Ethanol against Listeria species

    Directory of Open Access Journals (Sweden)

    Y Yakubu

    2012-04-01

    Full Text Available This study was carried out in order to determine the disinfectant effect of Methylated spirit® (95% methanol and 5% ethanol as a teat dip against Listeria species. Hand milking was employed to collect 576 (288 x 2 raw milk samples from different lactating cows within Sokoto metropolis (Nigeria. 288 samples were collected before disinfecting the udder teats with Methylated spirit®, while the other 288 were collected after disinfection with Methylated spirit®. The samples were analyzed using selective culture and isolation technique in which the 288 samples collected before disinfection, 114 (39.6% were positive for Listeria species. Among the positive samples 44 (38.6% were Listeria innocua, 16 (14.0% Listeria ivanovii, 36 (31.6% Listeria monocytogenes, 11 (9.6% Listeria welshimeri and 7 (6.1% Listeria seeligeri, while none of the 288 samples collected after disinfection was positive. The study has shown high prevalence of Listeria species in milk collected without washing/disinfecting the teats and has also established the sensitivity of Listeria species to methylated ethanol which can be used as dip for disinfecting udder teats before milking in order to prevent contamination with Listeria species and other methylated spirit-sensitive organisms. This study is essential to educate Fulani herdsmen and other milk handlers on the importance of disinfecting udder teats before milking. [Vet. World 2012; 5(2.000: 91-93

  13. Teat order affects postweaning behaviour in piglets

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    Roberta Sommavilla

    2015-09-01

    Full Text Available The objective of this study was to investigate if piglets that suck anterior teats differ from the others in the litter in birth weight, if they have higher growth rate during lactation, and if this affects behaviour and post-weaning weight gain, when piglets change to a solid diet. For this, the teat order of 24 litters was determined during suckling. Piglets were weaned on the 28thday of age, and 24 groups were formed, composed of one piglet that sucked on the first two pairs of teats (AT and three piglets that sucked on the other teats (OT. Even though weight at birth did not vary according to teat order, weight gain at weaning differed between the groups (AT: 6.64, S.E. 0.20kg, OT: 5.73, S.E. 0.13kg; P

  14. Effect of presampling procedures on real-time PCR used for diagnosis of intramammary infections with Staphylococcus aureus in dairy cows at routine milk recordings

    DEFF Research Database (Denmark)

    Mahmmod, Yasser; Klaas, Ilka Christine; Nielsen, Søren Saxmose

    2013-01-01

    the farmers' routine premilking preparations, 624 cows of the 1,199 cows were randomly selected for bacterial culture preceded by presampling procedures. These procedures were: cleaning of udder teats, removing the first streams of milk, and 70% alcohol teat disinfection. Data on parity, somatic cell counts...

  15. Teated

    Index Scriptorium Estoniae

    2008-01-01

    Kontserdid TÜ aulas: Tartu Ülikooli kammerkoori kevadkontsert 16. märtsil, pianist Peep Lassmann 18. märtsil (kavas: Sumera "Pala aastast 1981", Liszt-Rossini "Stabat Mater", Liszt-Verdi "Rigoletto parafraas", Liszt "Tuisk" ja "Hispaania rapsoodia"), saksofonikvartett Sax-Est 19. märtsil, kontsert "Richard Ritsing - 105" 28. märtsil

  16. In vitro efficacy of teat antiseptics against Staphylococcus aureus strains isolated from bovine mastitis

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    Renata Paoli Santos

    2016-08-01

    Full Text Available The process of teat disinfection is a widely accepted component of successful mastitis control programs by reducing the number of bacteria on the teat skin and healing teat lesions. For contagious pathogens such as Staphylococcus aureus, post-milking teat disinfection remains a simple, effective and economical practice for prevention of new intramammary infections (IMIs of lactating dairy cows. Despite the universal acceptance of teat dipping as a method of mastitis control, variations in the susceptibility and resistance profile of mastitis pathogens among antiseptics have been described. Thus, here we sought to explore the in vitro efficacy of the followings antiseptics against S. aureus isolated from IMIs: chlorhexidine (2.0%, chlorine (2.5%, quarternary ammonium (4.0%, lactic acid (2.0% and iodine (0.6%. We used 50 S. aureus strains isolated from bovine IMIs from 50 dairy herds located at Minas Gerais, São Paulo, Paraná and Rio Grande do Sul States (Brazil. The antiseptics were evaluated at four different specific intervals (15, 30, 60 and 300 s. We found a higher activity for quarternary ammonium and chlorhexidine against S. aureus at all time-points, followed by iodine and then chlorine. Lactic acid treatment produced the worst results for all time-points and strains. Due to variations in the sensitivity and resistance profile of antiseptics against S. aureus isolated from IMIs, the effectiveness of the antiseptics against the major mastitis pathogens should be periodically evaluated in dairy farms in an attempt to reduce the rate of new IMIs in the herd.

  17. Estimating teat canal cross-sectional area to determine the effects of teat-end and mouthpiece chamber vacuum on teat congestion.

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    Penry, J F; Upton, J; Mein, G A; Rasmussen, M D; Ohnstad, I; Thompson, P D; Reinemann, D J

    2017-01-01

    The primary objective of this experiment was to assess the effect of mouthpiece chamber vacuum on teat-end congestion. The secondary objective was to assess the interactive effects of mouthpiece chamber vacuum with teat-end vacuum and pulsation setting on teat-end congestion. The influence of system vacuum, pulsation settings, mouthpiece chamber vacuum, and teat-end vacuum on teat-end congestion were tested in a 2×2 factorial design. The low-risk conditions for teat-end congestion (TEL) were 40 kPa system vacuum (Vs) and 400-ms pulsation b-phase. The high-risk conditions for teat-end congestion (TEH) were 49 kPa Vs and 700-ms b-phase. The low-risk condition for teat-barrel congestion (TBL) was created by venting the liner mouthpiece chamber to atmosphere. In the high-risk condition for teat-barrel congestion (TBH) the mouthpiece chamber was connected to short milk tube vacuum. Eight cows (32 quarters) were used in the experiment conducted during 0400 h milkings. All cows received all treatments over the entire experimental period. Teatcups were removed after 150 s for all treatments to standardize the exposure period. Calculated teat canal cross-sectional area (CA) was used to assess congestion of teat tissue. The main effect of the teat-end treatment was a reduction in CA of 9.9% between TEL and TEH conditions, for both levels of teat-barrel congestion risk. The main effect of the teat-barrel treatment was remarkably similar, with a decrease of 9.7% in CA between TBL and TBH conditions for both levels of teat-end congestion risk. No interaction between treatments was detected, hence the main effects are additive. The most aggressive of the 4 treatment combinations (TEH plus TBH) had a CA estimate 20% smaller than for the most gentle treatment combination (TEL plus TBL). The conditions designed to impair circulation in the teat barrel also had a deleterious effect on circulation at the teat end. This experiment highlights the importance of elevated mouthpiece

  18. Bacterial counts on teat skin and in new sand, recycled sand, and recycled manure solids used as bedding in freestalls.

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    Rowbotham, R F; Ruegg, P L

    2016-08-01

    On modern dairy farms, environmental mastitis pathogens are usually the predominant cause of mastitis, and bedding often serves as a point of exposure to these organisms. The objective of this longitudinal study was to determine bacterial populations of 4 different bedding types [deep-bedded new sand (NES), deep-bedded recycled sand (RS), deep-bedded manure solids (DBMS), and shallow-bedded manure solids over foam core mattresses (SBMS)] and of teat skin swabs of primarily primiparous cows housed in a single facility over all 4 seasons. Samples of bedding were collected weekly (n=49wk) from pens that each contained 32 lactating dairy cows. Throughout the length of the same period, composite swabs of teat skin were collected weekly from all cows before and after premilking teat sanitation. Median numbers of streptococci and streptococci-like organisms (SSLO) were >8.6×10(6) cfu/g and >6.9×10(3) cfu/teat swab for all bedding types and teat swabs, respectively. Numbers of SSLO were greatest in samples of SBMS (2.1×10(8) cfu/g) and least in samples of NES (8.6×10(6) cfu/g), RS (1.3×10(7) cfu/g), and DBMS (1.7×10(7) cfu/g). Numbers of gram-negative bacteria in bedding (5.5×10(4) to 1.2×10(7) cfu/g) were fewer than numbers of SSLO (8.6×10(6) to 2.1×10(8) cfu/g). Numbers of coliform bacteria were greatest in samples of DBMS (2.2×10(6) cfu/g) and least in samples of NES (3.6×10(3) cfu/g). In general, the relative number of bacteria on teat skin corresponded to exposure in bedding. Numbers of gram-negative bacteria recovered from prepreparation teat swabs were greatest for cows bedded with DBMS (1.0×10(4) cfu/swab) and RS (2.5×10(3) cfu/swab) and least for cows bedded with NES (5.8×10(2) cfu/swab). Median numbers of coliform and Klebsiella spp. recovered from prepreparation teat swabs were below the limit of detection for all cows except those bedded with DBMS. Numbers of SSLO recovered from prepreparation teat swabs were least for cows bedded with DBMS (6.9

  19. Congenital Absence of a Teat in a Japanese Black Heifer

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    Mohamed Elshabrawy Ghanem

    2011-01-01

    Full Text Available A case of Japanese Black heifer with a congenital absence of teat (athelia was observed at Highashi-Hiroshima Agricultural High School, Hiroshima Prefecture, Japan. The heifer was born after transfer of embryo from Japanese Black cattle. The sire of the heifer was a proven Japanese Black. The birth weight of the heifer was 27 kg. On physical examination of the heifer at 21 months after birth, the teat at fore left was absent and the remaining three teats were normal in shape without any physical abnormalities. Per rectal palpation of the genital organs revealed the normal cervix and uterine horns. It was difficult to palpate the ovaries due to the fat around the organs. Blood samples were taken for cytogenetic and DNA testing. The heifer had normal chromosomal set. The heifer was culled due to its mammary abnormality. This might be the first to report a case of congenital absence of a teat in Japanese Black heifers.

  20. Milk production in sows from a teat in second parity is influenced by whether it was suckled in first parity

    DEFF Research Database (Denmark)

    Farmer, Chantal; Palin, M-F; Theil, Peter Kappel

    2012-01-01

    ) different teats suckled in 2 subsequent lactations (treated, TRT; n = 25). In the first lactation, over half of the teats (Teats 1, 2, 5, 6, and 7 from 1 side of the udder, and Teats 3, 4, and 7 from the other side) were sealed with tape so that they were nonfunctional. During the next lactation, the CTL...... group had the same teats sealed as in the first lactation, whereas the opposite teats were sealed for the TRT group. In both parities, litters were standardized to 7 piglets around birth and to 6 piglets (1 piglet per available teat) at 48 h postpartum. During the second lactation, piglets were weighed...

  1. The association between bedding material and the bacterial counts of Staphylococcus aureus, Streptococcus uberis and coliform bacteria on teat skin and in teat canals in lactating dairy cattle.

    Science.gov (United States)

    Paduch, Jan-Hendrik; Mohr, Elmar; Krömker, Volker

    2013-05-01

    Several mastitis-causing pathogens are able to colonize the bovine teat canal. The objective of this study was to investigate the association between the treatment of sawdust bedding with a commercial alkaline conditioner and the bacterial counts on teat skin and in the teat canal. The study used a crossover design. Ten lactating Holstein cows that were free of udder infections and mastitis were included in the study. The animals were bedded on either untreated sawdust or sawdust that had been treated with a hydrated lime-based conditioner. Once a day, fresh bedding material was added. After 3 weeks, the bedding material was removed from the cubicles, fresh bedding material was provided, and the cows were rotated between the two bedding material groups. Teat skin and teat canals were sampled using the wet and dry swab technique after weeks 1, 2, 3, 4, 5 and 6. Staphylococcus aureus, Streptococcus uberis, Escherichia coli and other coliform bacteria were detected in the resulting agar plate cultures. The treatment of the bedding material was associated with the teat skin bacterial counts of Str. uberis, Esch. coli and other coliform bacteria. An association was also found between the bedding material and the teat canal bacterial counts of coliform bacteria other than Esch. coli. For Staph. aureus, no associations with the bedding material were found. In general, the addition of a hydrated lime-based conditioner to sawdust reduces the population sizes of environmental pathogens on teat skin and in teat canals.

  2. APPLICATION OF CHLORINE DIOXIDE FOR PRE-MILKING TREATMENT OF COW UDDER AND DEVELOPMENT OF MEDICATION FOR POST-MILKING TREATMENT OF DUGS OF COW UDDER

    OpenAIRE

    Komarov V. Y.

    2015-01-01

    In the present article the main research results of investigation of the means of pre-milking and postmilking treatment of cow udder and dugs are presented. The treatment of cow udder dugs produces great effect on the milk quality, the incidence level of mastitis of cows in the herd, extension and pathogenic agents transmission from sick to healthy animals; and also udder treatment provides hygienic protection of udder dugs. Tree concentrations of detergent of chloride dioxide were tested. Wh...

  3. Effect of different heat treatments and disinfectants on the survival of Prototheca zopfii.

    Science.gov (United States)

    Lassa, Henryka; Jagielski, Tomasz; Malinowski, Edward

    2011-03-01

    Bovine mastitis caused by the yeast-like alga Prototheca zopfii represents a serious veterinary problem and may result in heavy economic losses to particular dairy farms. The purpose of this study was to evaluate the survival of 50 isolates of P. zopfii in milk subjected to different heat treatments and the survival of further 106 P. zopfii isolates after exposure to three classes of teat disinfectants: iodine (Dipal), quaternary ammonium compounds (Teat), and dodecylbenzenesulphonic acid (Blu-gard). Of the 50 isolates tested for thermal tolerance, 29 (58%) survived heat treatment at 62 °C for 30 s and 13 (26% of all isolates) of those survived after heat treatment at 72 °C for 15 s. None of the 106 isolates were able to withstand the in-use concentrations of the three disinfectants tested. The highest disinfectant concentrations that permitted survival of at least one isolate were dilutions: 1:1,000 for Dipal (survival rate of 52.8-57.5%), 1:100 for Teat (88.7-90.6%), and 1:10 for Blu-gard (100%). No differences in the survival rates of P. zopfii were observed with respect to the duration of exposure to disinfectant. The results of this study support the previous findings that P. zopfii may resist high-temperature treatments, including that applied in the high-temperature, short-time (HTST) pasteurization process. The obtained data also demonstrate the efficacy of the three classes of teat disinfectants against P. zopfii, with the efficacy of iodine being most pronounced. The study emphasizes the necessity of using higher temperatures in the pasteurization of raw milk to kill the Prototheca algae, as well as the particular suitability of the iodine for the control procedures of protothecal mastitis.

  4. Relationship between teat-end callosity and occurrence of clinical mastitis

    NARCIS (Netherlands)

    Neijenhuis, F.; Barkema, H.W.; Hogeveen, H.

    2001-01-01

    A longitudinal study in 15 herds, with a total of 2157 cows, was conducted to examine the relationship between teat-end callosity (TEC) and the incidence of clinical mastitis. During the 1.5-yr study period, clinical mastitis was diagnosed by the farmers based on clinical signs. Teat-end callosity

  5. The effect of post milking test dip and suckling on teat skin condition, bacterial colonisation, and udder health

    DEFF Research Database (Denmark)

    Rasmussen, M.D.; Larsen, H.D.

    1998-01-01

    The teat skin of cows was scored (1 : smooth as silk; 2: smooth; 3: slightly rough; 4: rough; 5: cracked; and 6: sores) by trained technicians who moved their fingers down the barrel of the teat with a light touch. Technicians ranked the same population of teats in the same rank order, but their ...

  6. A main factors affecting average number of teats in pigs

    Directory of Open Access Journals (Sweden)

    Emil Krupa

    2016-09-01

    Full Text Available The influence of factors (breed, year and season of farrowing, herd, parity order, sire of litter, total number of born piglets - TNB, number of piglets born alive - NBA, number of weaned piglets - NW, and linear and quadratic regression on the number of teats, found for all piglets in the litter till ten days after born, expressed as arithmetic mean for each litter as sum of all teats number of each piglet in appropriate litter divided by number of piglets in this litter at first litter (ANT1 and second and subsequent litters (ANT2+ were analysed. The coefficient of determination was 0.46 and 0.33 for ANT1 and ANT2+, respectively. The statistically high influence (P<0.001 on ANT1 and ANT2+ was determined for year and season of farrowing, herd, parity order (only for ANT2+ and sire of litter effects. Impact of breed was found only on ANT2+ (P<0.001. The rest of factors have negligible of no impact on traits. Based on the data available for analyses, obtained results will serve as a relevant set-up in developing the model for genetic evaluation for these traits.

  7. Genetic relatedness and virulence factors of bovine Staphylococcus aureus isolated from teat skin and milk.

    Science.gov (United States)

    da Costa, L B; Rajala-Schultz, P J; Hoet, A; Seo, K S; Fogt, K; Moon, B S

    2014-11-01

    The objective of this study was to assess the role of teat skin colonization in Staphylococcus aureus intramammary infections (IMI) by evaluating genetic relatedness of Staph. aureus isolates from milk and teat skin of dairy cows using pulsed-field gel electrophoresis and characterizing the isolates based on the carriage of virulence genes. Cows in 4 known Staph. aureus-positive herds were sampled and Staph. aureus was detected in 43 quarters of 20 cows, with 10 quarters positive in both milk and skin (20 isolates), 18 positive only in milk, and 15 only on teat skin. Quarters with teat skin colonized with Staph. aureus were 4.5 times more likely to be diagnosed with Staph. aureus IMI than quarters not colonized on teat skin. Three main clusters were identified by pulsed-field gel electrophoresis using a cutoff of 80% similarity. All 3 clusters included both milk and skin isolates. The majority of isolates (72%) belonged to one predominant cluster (B), with 60% of isolates in the cluster originating from milk and 40% from teat skin. Genotypic variability was observed within 10 pairs (formed by isolates originating from milk and teat skin of the same quarter), where isolates in 5 out of the 10 pairs belonged to the same cluster. Forty-two virulence factors were screened using PCR. Some virulence factors were carried more frequently by teat skin isolates than by milk isolates or isolates from quarters with high somatic cell counts. Isolates in the predominant cluster B carried virulence factors clfA and clfB significantly more often than isolates in the minor clusters, which may have assisted them in becoming predominant in the herds. The present findings suggest that teat skin colonization with Staph. aureus can be an important factor involved in Staph. aureus IMI. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  8. The pore of the leaf cavity of Azolla species: teat cell differentiation and cell wall projections.

    Science.gov (United States)

    Veys, P; Lejeune, A; Van Hove, C

    2002-02-01

    The differentiation of the specialized secretory teat cells of the leaf cavity pore of Azolla species was investigated at the ultrastructural level with emphasis on their peculiar cell wall projections. The results indicated that the projections are formed as soon as the teat cells complete their differentiation and that their production is principally associated with changes in endoplasmic reticulum profiles. The number of projections increases with the teat cell age and is stimulated under salt and P deficiency stresses. Salt stress also promotes their emergence on Azolla species that under normal conditions do not produce projections. Cytochemical tests on different Azolla species showed that the projection composition is almost identical: proteins, acidic polysaccharides, and pectin are always detected. This study revealed that Azolla teat cell projections differ fundamentally from other types of hitherto described cell wall projections that are considered as remnant structures from cell separation. In contrast, in Azolla teat cells projections are actively produced and compounds are excreted by an exocytotic mechanism. The possible role of the projections in the symbiosis of Azolla spp. with Anabaena azollae is discussed.

  9. Growth of Cinta Senese piglets as affected by location of the suckled teat

    Directory of Open Access Journals (Sweden)

    Martina Bianchi

    2010-01-01

    Full Text Available The experimental animals were 18 Cinta Senese sows (7 primiparous and 11 multiparous and relative purebred off-  spring. Individual weight of piglets was recorded at birth (or shortly afterwards to the nearest 50 g and subsequently  every 3-5 days up to weaning. At each recording, piglets were ranked in decreasing order according to weight within their  respective litters. The behavior of a subsample of 8 sows and litters was observed during suckling, by recording the  teat–piglet coupling. The sows had 12 functional teats, equally distributed in the two symmetric rows, that were num-  bered as pairs in the antero-posterior direction.  Starting from the third week, piglets of multiparous sows showed a faster growth rate than those of the primiparous ones.  Repeatability of the piglets’ weight during the suckling period was high (r = 0.56 and repeatability of rank was even  higher, but decreased up to weaning. Anterior teats were the most occupied and showed the highest suckling fidelity  (consistency of suckling position. Various statistical analyses about the dependence of piglet weight (or weight rank with-  in litter on teat order indicated the highest milk productivity of the first teats and the lowest of the 5th & 6th teat pairs.

  10. Dry cow therapy with a non-antibiotic intramammary teat seal - a review

    Directory of Open Access Journals (Sweden)

    Crispie Fiona

    2004-07-01

    Full Text Available Dry cow antibiotic therapy is used to eliminate existing intramammary infections and to prevent new infections in the dry period. It is implemented as part of a total management system known as the 'Five-Point Plan' for mastitis control. Recent public concerns over the widespread prophylactic use of antibiotics, coupled with an increasing interest in organic farming, have lead to a re-evaluation of the treatment of cows at drying-off. As a result, attention has focussed on the use of novel alternatives to antibiotic therapy at the end of lactation. One such therapy involves the application of a non-antibiotic bismuth-based intramammary teat seal designed for use in cows with low cell counts at the end of lactation. Like the keratin plug that forms naturally in teats of cows that have been dried-off, teat seal forms a physical barrier to invading pathogens. To date, a number of independent studies have shown that teat seal is as effective as traditional dry cow antibiotic products in preventing the occurrence of new infection during the dry period in cows with somatic cell counts of ≤200,000 cells ml-1 at drying-off. This paper reviews the efficacy of teat seal in preventing dry period mastitis in both conventional and organic dairying systems.

  11. Prepartum teat apex colonization with Staphylococcus chromogenes in dairy heifers is associated with low somatic cell count in early lactation.

    Science.gov (United States)

    De Vliegher, S; Laevens, H; Devriese, L A; Opsomer, G; Leroy, J L M; Barkema, H W; de Kruif, A

    2003-04-02

    A high number of dairy heifers freshen with udder health problems. The prevalence of teat apex colonization (TAC) with Staphylococcus chromogenes, one of the most widespread coagulase-negative staphylococci (CNS) in milk samples from freshly calved dairy heifers, was measured cross-sectionally in non-lactating heifers on eight commercial dairy farms in Belgium. The influence of age on this prevalence, and the association between teat apex colonization with S. chromogenes prepartum and quarter milk somatic cell count (SCC) in early lactation were studied. In total, 492 teat apices were sampled from 123 heifers. The age of the heifers varied from 8 to 34 months. Overall, 20% of the heifers had at least one teat apex colonized with S. chromogenes. Of all teats sampled, 10% were colonized with S. chromogenes. The chance of having at least one teat apex colonized with S. chromogenes increased with age of the heifer. The presence of prepartum teat apex colonization with S. chromogenes was not associated with intramammary infection (IMI) early postpartum with the same bacterium. On the contrary, teat apex colonization with S. chromogenes prepartum appeared to protect quarters in the first few days of lactation from having somatic cell count >or=200000cells/ml milk, commonly accepted as the threshold for intramammary infection.

  12. Teat apex colonization with coagulase-negative Staphylococcus species before parturition: Distribution and species-specific risk factors.

    Science.gov (United States)

    De Visscher, A; Piepers, S; Haesebrouck, F; De Vliegher, S

    2016-02-01

    Coagulase-negative staphylococci (CNS) are the main cause of bovine intramammary infections and are also abundantly present in extramammary habitats such as teat apices. Teat apex colonization (TAC) with CNS has already been explored in lactating dairy cows at the species level, whereas this is not true for dry cows and end-term heifers. Therefore, the aim of this observational study was to describe CNS TAC in nonlactating dairy cows and end-term heifers in Flemish dairy herds and to identify associated risk factors at the herd, cow, and quarter level. All CNS were molecularly identified to the species level using transfer RNA intergenic spacer PCR (tDNA-PCR) and sequencing of the 16S rRNA gene, allowing for species-specific statistical analyses using multivariable, multilevel logistic regression. Staphylococcus devriesei, Staphylococcus chromogenes, Staphylococcus haemolyticus, and Staphylococcus equorum were the most frequently isolated species. Staphylococcus chromogenes was the sole species colonizing teat apices of cows and heifers in all herds, whereas large between-herd differences were observed for the other species. Teat apices of red and white Holstein Friesians, of quarters dried off without an internal teat sealer, and swabbed in months with lower precipitation and higher ambient temperature were significantly more likely to be colonized by S. devriesei. Slightly dirty teat apices and teat apices swabbed in months with lower precipitation had higher odds of being colonized by S. chromogenes, whereas teat apices sampled in months with lower precipitation and higher ambient temperature were more likely to be colonized by S. haemolyticus. Dirty teat apices and teat apices swabbed in months with lower ambient temperature in combination with low precipitation had higher odds of being colonized by S. equorum. Diverse factors explaining CNS TAC, yet mostly related to humidity, ambient temperature, and hygiene, substantiate differences in epidemiological

  13. Cane molasses and NaOH teated bagacillo diets for lambs | Chicco ...

    African Journals Online (AJOL)

    Cane molasses and NaOH teated bagacillo diets for lambs. C.F. Chicco, G Garcia, C Fernandez, C.R. Prays. Abstract. The eftect of alkali-treated bag acillo in diets varying in proportion of bagacillo and mollasses was studied in lambs. The bagacillo was treated with a concentration solution of NaOH in a horizontald rum-type ...

  14. Effect of Modified Pre-Milking Sanitizing Approaches on Raw Milk Quality Obtained from the Dairy Farmers of Tawau Area, Sabah

    Directory of Open Access Journals (Sweden)

    Sim Kheng Yuen

    2016-01-01

    Full Text Available The aim of the study was to investigate the raw milk hygiene and quality among the small holder dairy farmers in Tawau area. A total of 216 samples were collected from the respective dairy farmers and milk collecting centre located at Mile 15, Tawau. Preliminary results indicated that the quality of the raw milks obtained at farm level contained were inferior with high bacteria load (> than 107 CFU/ml. The total coliform (2.9-3.8 CFU/mL and Staphylococcus count (2.3-3.6 CFU/mL were relatively high in certain samples. However, none of the food borne pathogens was found. Trace back study revealed that the causes of contamination were attributed by poor hygienic handling among the dairy farmers and insufficient for immediate chilling of raw milk. A significant reduction in bacteria load was observed if the raw milk chilled immediately at farm. The implementation of modified pre-milking sanitizing practices improved the microbiology quality of the raw milks obtained from respective dairy farms. Future study will focus more on the effect of prolong storage towards the microbiological quality of raw milk.

  15. Subclinical and clinical mastitis in heifers following the use of a teat sealant precalving.

    Science.gov (United States)

    Parker, K I; Compton, C; Anniss, F M; Weir, A; Heuer, C; McDougall, S

    2007-01-01

    This study investigated the effect in heifers of infusion of a bismuth subnitrate teat-canal sealant and bacterial intramammary infection (IMI) precalving on prevalence of postcalving IMI and incidence of clinical mastitis in the first 2 wk postcalving. Glands (n = 1,020) from heifers (n = 255) in 5 seasonally calving, pasture-fed dairy herds were randomly assigned within heifer to 1 of 4 treatment groups (no treatment; mammary gland secretion collection; infusion of a teat sealant; or sample collection with infusion of teat sealant). Heifers within a herd were enrolled on one calendar day, 31 d on average before the planned start of the seasonal calving period. Duplicate milk samples were collected from each gland within 4 d after calving for bacterial culture. Herd owners collected duplicate milk samples, before treatment, for bacterial culture from glands they defined as having clinical mastitis. The gland prevalence of IMI precalving was 15.5% and did not differ between herds. Bacteria isolated precalving included coagulase-negative staphylococci (76.9% of all bacteriologically positive samples), Streptococcus uberis (14.1%), Staphylococcus aureus (5.1%), Corynebacterium spp. (3.8%), and others (0.1%). The presence of an IMI precalving increased the risk of an IMI postcalving 3.6-fold and the risk of clinical mastitis 4-fold, relative to no IMI precalving. Infusion of the teat sealant reduced the risk of postcalving IMI due to Strep. uberis by 84%, and of clinical mastitis by 68%. Sampling the glands precalving had no effect on postcalving IMI or on clinical mastitis incidence. Use of an internal teat canal sealant in heifers precalving may be a useful tool for reducing the risk of subclinical and clinical mastitis in heifers.

  16. Communications of Staphylococcus aureus and non-aureus Staphylococcus species from bovine intramammary infections and teat apex colonization.

    Science.gov (United States)

    Mahmmod, Yasser S; Klaas, Ilka Christine; Svennesen, Line; Pedersen, Karl; Ingmer, Hanne

    2018-05-16

    The role of non-aureus staphylococci (NAS) in the risk of acquisition of intramammary infections with Staphylococcus aureus is vague and still under debate. The objectives of this study were to (1) investigate the distribution patterns of NAS species from milk and teat skin in dairy herds with automatic milking systems, and (2) examine if the isolated NAS influences the expression of S. aureus virulence factors controlled by the accessory gene regulator (agr) quorum sensing system. In 8 herds, 14 to 20 cows with elevated somatic cell count were randomly selected for teat skin swabbing and aseptic quarter foremilk samples from right hind and left front quarters. Teat skin swabs were collected using the modified wet-dry method and milk samples were taken aseptically for bacterial culture. Colonies from quarters with suspicion of having NAS in milk or teat skin samples (or both) were subjected to MALDI-TOF assay for species identification. To investigate the interaction between S. aureus and NAS, 81 isolates NAS were subjected to a qualitative β-galactosidase reporter plate assay. In total, 373 NAS isolates were identified representing 105 from milk and 268 from teat skin of 284 quarters (= 142 cows). Sixteen different NAS species were identified, 15 species from teat skin and 10 species from milk. The most prevalent NAS species identified from milk were Staphylococcus epidermidis (50%), Staphylococcus haemolyticus (15%), and Staphylococcus chromogenes (11%), accounting for 76%. Meanwhile, the most prevalent NAS species from teat skin were Staphylococcus equorum (43%), S. haemolyticus (16%), and Staphylococcus cohnii (14%), accounting for 73%. Using reporter gene fusions monitoring transcriptional activity of key virulence factors and regulators, we found that out of 81 supernatants of NAS isolates, 77% reduced expression of hla, encoding a-hemolysin, 70% reduced expression of RNAIII, the key effector molecule of agr, and 61% reduced expression of spa encoding

  17. In vitro growth inhibition of major mastitis pathogens by Staphylococcus chromogenes originating from teat apices of dairy heifers.

    Science.gov (United States)

    De Vliegher, S; Opsomer, G; Vanrolleghem, A; Devriese, L A; Sampimon, O C; Sol, J; Barkema, H W; Haesebrouck, F; de Kruif, A

    2004-07-14

    Earlier field observations suggest that teat apex colonization by Staphylococcus chromogenes pre-partum in dairy heifers protects udder quarters against elevated somatic cell counts early post-partum. To explain these findings, the in vitro inhibitory capability of S. chromogenes from teat apices of heifers towards some major mastitis pathogens was tested using a modified cross-streaking method. Two out of 10 S. chromogenes isolates, both originating from two different teats from the same heifer, consistently inhibited growth of all Staphylococcus aureus, Streptococcus dysgalactiae, and Streptococcus uberis strains, but none of the Escherichia coli strains. The present study, therefore, supports the protective effect of teat apex colonization by S. chromogenes by in vitro production of inhibitory substances.

  18. Spiral-shaped disinfection reactors

    KAUST Repository

    Ghaffour, Noreddine

    2015-08-20

    This disclosure includes disinfection reactors and processes for the disinfection of water. Some disinfection reactors include a body that defines an inlet, an outlet, and a spiral flow path between the inlet and the outlet, in which the body is configured to receive water and a disinfectant at the inlet such that the water is exposed to the disinfectant as the water flows through the spiral flow path. Also disclosed are processes for disinfecting water in such disinfection reactors.

  19. Spiral-shaped disinfection reactors

    KAUST Repository

    Ghaffour, NorEddine; Ait-Djoudi, Fariza; Naceur, Wahib Mohamed; Soukane, Sofiane

    2015-01-01

    This disclosure includes disinfection reactors and processes for the disinfection of water. Some disinfection reactors include a body that defines an inlet, an outlet, and a spiral flow path between the inlet and the outlet, in which the body

  20. Cross-sectional study to identify staphylococcal species isolated from teat and inguinal skin of different-aged dairy heifers.

    Science.gov (United States)

    Adkins, P R F; Dufour, S; Spain, J N; Calcutt, M J; Reilly, T J; Stewart, G C; Middleton, J R

    2018-04-01

    The purpose of this study was to describe the prevalence and distribution of staphylococcal species on the teat and inguinal skin of dairy heifers across the various stages of the heifer life cycle. The cross-sectional study included 106 Holstein heifers with an age range of 0 d to 27 mo that were selected from 11 different groups, based on housing type and age, on a single dairy operation. A composite swabbing sample including all 4 teats and a second composite sample including both inguinal regions of each heifer were collected using gas-sterilized electrostatic dusters (Swiffers; Procter and Gamble, Cincinnati, OH). Swabbing samples were mixed with 10 mL of sterile saline, agitated, and cultured on mannitol salt agar plates. At 24 h, plates were read and up to 10 staphylococcal colonies were saved for further analysis. Staphylococcal isolates were speciated using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry or PCR amplification and partial sequencing of rpoB or tuf. The prevalence of staphylococci was compared between the inguinal and teat regions using the chi-squared or Fisher's exact test, as applicable. Logistic regression models were used to investigate the relationship between a heifer's age (treated as a quantitative continuous variable) and the probability of isolating a given staphylococcal species from a given body site (inguinal region or teats). Overall, the most common species identified were Staphylococcus haemolyticus followed by Staphylococcus chromogenes, Staphylococcus xylosus, Staphylococcus devriesei, and Staphylococcus sciuri. Staphylococcus aureus was more prevalent on the teat than in the inguinal region, whereas Staphylococcus arlettae was more prevalent in the inguinal region than on the teat. All other staphylococcal species were as likely to be found on the teat skin as the inguinal region skin. Isolation from the inguinal and teat skin was associated with age for Staphylococcus agnetis, S. chromogenes

  1. Applications of Photocatalytic Disinfection

    Directory of Open Access Journals (Sweden)

    Joanne Gamage

    2010-01-01

    Full Text Available Due to the superior ability of photocatalysis to inactivate a wide range of harmful microorganisms, it is being examined as a viable alternative to traditional disinfection methods such as chlorination, which can produce harmful byproducts. Photocatalysis is a versatile and effective process that can be adapted for use in many applications for disinfection in both air and water matrices. Additionally, photocatalytic surfaces are being developed and tested for use in the context of “self-disinfecting” materials. Studies on the photocatalytic technique for disinfection demonstrate this process to have potential for widespread applications in indoor air and environmental health, biological, and medical applications, laboratory and hospital applications, pharmaceutical and food industry, plant protection applications, wastewater and effluents treatment, and drinking water disinfection. Studies on photocatalytic disinfection using a variety of techniques and test organisms are reviewed, with an emphasis on the end-use application of developed technologies and methods.

  2. Safety of food contact silicone rubber: Liberation of volatile compounds from soothers and teats

    DEFF Research Database (Denmark)

    Lund, Kirsten H.; Petersen, Jens Højslev

    2002-01-01

    The release of volatile compounds from soothers and teats made from silicone rubber has been investigated. Firstly, measurements of the total release of volatiles were performed according to the method in the draft European standard (CEN). Weight losses of 0.17-0.80% after four hours at 200 degrees......C were observed using gravimetric measurements. One product had a weight loss above the proposed CEN limit of 0.5%. Secondly, the volatile compounds were identified using a thermal desorption/cold trap injector on a gas chromatograph equipped with infrared spectroscopic (IR) and mass spectrometric (MS...

  3. Humidifier disinfectants, unfinished stories

    Directory of Open Access Journals (Sweden)

    Yeyong Choi

    2016-02-01

    Full Text Available Once released into the air, humidifier disinfectants became tiny nano-size particles, and resulted in chemical bronchoalveolitis. Families had lost their most beloved members, and even some of them became broken. Based on an estimate of two million potential victims who had experienced adverse effects from the use of humidifier disinfectants, we can say that what we have observed was only the tip of the iceberg. Problems of entire airways, as well as other systemic effects, should be examined, as we know these nano-size particles can irritate cell membranes and migrate into systemic circulation. The story of humidifier disinfectant is not finished yet.

  4. Environmental cleaning and disinfection.

    Science.gov (United States)

    Traverse, Michelle; Aceto, Helen

    2015-03-01

    The guidelines in this article provide veterinarians, veterinary technicians, and veterinary health care workers with an overview of evidence-based recommendations for the best practices associated with environmental cleaning and disinfection of a veterinary clinic that deals with small animals. Hospital-associated infections and the control and prevention programs necessary to alleviate them are addressed from an environmental perspective. Measures of hospital cleaning and disinfection include understanding mechanisms and types of contamination in veterinary settings, recognizing areas of potential concern, addressing appropriate decontamination techniques and selection of disinfectants, the management of potentially contaminated equipment, laundry, and waste management, and environmental surveillance strategies. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. The influence of milking procedures on cow’s teat tissue, milk yield and milking time

    Directory of Open Access Journals (Sweden)

    Saša Špoljar

    2004-04-01

    Full Text Available The aim of this study was to evaluate the effect of two different milking procedures on teat length and diameter, milk yield and milking time. During the first milking procedure the milker decides when to remove the milking cluster from the udder, while in the second an automatic cluster removal, when milk flow was lower than 200 g/min, was performed. Measurements were made on two commercial farms B and A on 15 randomly chosen cows without any clinical sign of mastitis. There were no significant differencesbetween those farms in teat length and diameter differences before and after the milking. Average milking time on farm A was 6 min and 58 s, while on farm B was 5 min and 3 s. Average milk yield was 12.9 kg on farm B and 13.4 kg on farm A. Milking time was considerably shorter on farm B compared to farm A, while milk yield was almost equal on both farms. Automatic cluster weighting 2 kg removal was performed when milk flow was lower than 200 g/min in order to shorten the time needed to milk the cow, ensuring good udder health.

  6. Disinfection of drinking water

    International Nuclear Information System (INIS)

    Ensenauer, P.

    1977-01-01

    Some methods for disinfecting drinking water are described, e.g. UV irradiation (optimal wavelength 210-250mm) with the advantage of constant water composition and the resulting danger of re-infection. (AJ) [de

  7. Disinfection of drinking water

    Energy Technology Data Exchange (ETDEWEB)

    Ensenauer, P

    1977-01-01

    Some methods for disinfecting drinking water are described, e.g. UV irradiation (optimal wavelength 210-250mm) with the advantage of constant water composition and the resulting danger of re-infection.

  8. Unraveling the microbiota of teat apices of clinically healthy lactating dairy cows, with special emphasis on coagulase-negative staphylococci.

    Science.gov (United States)

    Braem, G; De Vliegher, S; Verbist, B; Piessens, V; Van Coillie, E; De Vuyst, L; Leroy, F

    2013-03-01

    Swab samples (n=72) obtained from the teat apex of lactating dairy cows without visual signs of inflammation (n=18) were gathered on 2 well-managed Flemish dairy herds (herds 1 and 2) during the same month to assess the bacterial diversity of teat apices before milking. A combination of both culture-dependent [plating and (GTG)(5)-PCR fingerprinting of the colonies] and culture-independent [denaturing gradient gel electrophoresis (PCR-DGGE)] techniques indicated that the teat apices contain a wide diversity of bacterial genera. Despite a low bacterial load, 20 bacterial genera of 3 phyla (Actinobacteria, Firmicutes, and Proteobacteria) were present. The most prevalent bacteria were the coagulase-negative staphylococci (CNS), encompassing a total of 15 species, which were identified to the species level using a combination of (GTG)(5)-PCR fingerprinting, gene sequencing (16S ribosomal RNA and rpoB genes), and a novel PCR-DGGE technique based on the tuf-PCR amplicon. Overall bacterial diversity did not differ significantly between the herds or between noninfected and subclinically infected quarters in herd 1. In herd 1, borderline significant lower CNS species diversity was found on teat apices of noninfected quarters compared with subclinically infected quarters. The most prevalent CNS species were Staphylococcus haemolyticus and Staphylococcus equorum in both herds and Staphylococcus carnosus in herd 2. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  9. Communications of Staphylococcus aureus and non-aureus Staphylococcus species from bovine intramammary infections and teat apex colonization

    DEFF Research Database (Denmark)

    Mahmmod, Yasser S.; Klaas, Ilka Christine; Svennesen, Line

    2018-01-01

    The role of non-aureus staphylococci (NAS) in the risk of acquisition of intramammary infections with Staphylococcus aureus is vague and still under debate. The objectives of this study were to (1) investigate the distribution patterns of NAS species from milk and teat skin in dairy herds with au...

  10. Distribution of CNS Species on Teat Skin and in Milk Samples from Dairy Cows in Automatic Milking Systems

    DEFF Research Database (Denmark)

    Mahmmod, Yasser; Svennesen, Line; Pedersen, Karl

    identified in milk samples. Staphylococcus chromogenes was detected in both milk (n= 2) and teat skin (n= 1) samples. Data collection will be finished in April 2017. The final results will give new insights into herd specific CNS species patterns and the microbial ecology and epidemiology of common CNS...

  11. Short communication: quantification of the transmission of microorganisms to milk via dirt attached to the exterior of teats

    NARCIS (Netherlands)

    Vissers, M.M.M.; Driehuis, F.; Giffel, M.C.T.; Jong, de P.; Lankveld, J.M.G.

    2007-01-01

    Pathogens and spoilage microorganisms can be transmitted to milk via dirt (e.g., feces, bedding material, soil, or a combination of these) attached to the exterior of the cows¿ teats. To determine the relevance of this pathway and to perform quantitative microbial risk analysis of the microbial

  12. Effect of liner design, pulsator setting, and vacuum level on bovine teat tissue changes and milking characteristics as measured by ultrasonography

    Directory of Open Access Journals (Sweden)

    Gleeson David E

    2004-05-01

    Full Text Available Friesian-type dairy cows were milked with different machine settings to determine the effect of these settings on teat tissue reaction and on milking characteristics. Three teat-cup liner designs were used with varying upper barrel dimensions (wide-bore WB = 31.6 mm; narrow-bore NB = 21.0 mm; narrow-bore NB1 = 25.0 mm. These liners were tested with alternate and simultaneous pulsation patterns, pulsator ratios (60:40 and 67:33 and three system vacuum levels (40, 44 and 50 kPa. Teat tissue was measured using ultrasonography, before milking and directly after milking. The measurements recorded were teat canal length (TCL, teat diameter (TD, cistern diameter (CD and teat wall thickness (TWT. Teat tissue changes were similar with a system vacuum level of either 50 kPa (mid-level or 40 kPa (low-level. Widening the liner upper barrel bore dimension from 21.0 mm (P

  13. Emergency Disinfection of Drinking Water

    Science.gov (United States)

    How to boil and disinfect water to kill most disease-causing microorganisms during emergency situations where regular water service has been interrupted and local authorities recommend using only bottled water, boiled water, or disinfected water.

  14. Pengaruh teat dipping menggunakan dekok daun kersen (Muntingia calabura L. terhadap tingkat kejadian mastitis

    Directory of Open Access Journals (Sweden)

    Indra Kurniawan

    2014-02-01

    Full Text Available ABSTRACT: The study was carried out in Sidomulyo Village, Jabung, Malang Regen-cy from April 6th to May 6th, 2013. The objective of the study was to evaluate the influ-ence of Kersen leaf (Muntingia calabura L extract to reduce mastitis incidents. The materials used in this study were 15 Friesian Holstein crossbreed lactating dairy cows, chemical antiseptic, and Kersen leaf extract. The study used experiment Randomized Block Design with 3 treatments and 5 replications. The result shows that Kersen leaf extract was significantly (p>0.05 able to reduce mastitis incidents particularly 20% of Kersen leaf extract composition. The study suggests that Kersen leaf extract can be used as an effective substance in dipping solution for dairy cows Mastitis control program. Keywords: Kersen leaf extract, mastitis, teat dipping, dairy cows

  15. Disinfection by electrohydraulic treatment.

    Science.gov (United States)

    Allen, M; Soike, K

    1967-04-28

    Electrohydraulic treatment was applied to suspensions of Escherichia coli, spores of Bacillus subtilis var. niger, Saccharomyces cerevisiae, and bacteriophage T2 at an input energy that, in most cases, was below the energy required to sterilize. The input energy was held relatively constant for each of these microorganisms, but the capacitance and voltage were varied. Data are presented which show the degree of disinfection as a function of capacitance and voltage. In all cases, the degree of disinfection for a given input energy increases as both capacitance and voltage are lowered.

  16. UV disinfection of water

    International Nuclear Information System (INIS)

    Skipperud, E.; Johansen; Myhrstad, J.A.

    1978-01-01

    UV radiation has been found to have advantages over chloration for the disinfection of water. New regulations for dietary conditions on Norwegian ships introduced in 1974 led to increased use of UV disinfection, and this has in the following years spread to waterworks. The present article is based on a study to determine possible limitation. The nature of the injuries to the microorganisms is first discussed, together with repair mechanisms. A table is given showing the energy required for 90 and 100 percent inactivation of a number of microorganisms. Some other factors affecting UV inactivation are briefly mentioned. (JIW)

  17. DISTRIBUTION OF COAGULASE-NEGATIVE STAPHYLOCOCCI SPECIES ON TEAT SKIN AND IN MILK SAMPLES FROM DAIRY COWS IN AUTOMATIC MILKING SYSTEMS

    DEFF Research Database (Denmark)

    Mahmmod, Yasser Saadeldien Ibrahim; Svennesen, Line; Pedersen, Karl

    ) to identify the predisposing cow level risk factors for specific CNS IMI and teat colonization.In each herd, 30- 40 cows with somatic cell counts > 200,000 cells/ml in the previous milk recording are randomly selected and teat skin swabs and aseptic quarter foremilk samples are taken. Teat skin swabs...... are collected using a modified wet-dry method. First a wet swab immersed in ¼ Ringer’s solution followed by a dry swab are rotated 360° around the teat canal orifice and both swab tips transferred into one tube with 2 ml of ¼ Ringer’s solution. Samples are transported on ice for culturing in the laboratory...

  18. Benefits of automated acclimatization during the pre-milking phase of lactating girolando cows Benefícios da climatização automatizada na pré-ordenha de vacas girolando em lactação

    Directory of Open Access Journals (Sweden)

    Irenilson M. da Silva

    2011-10-01

    Full Text Available The aim of this paper was to evaluate the automated acclimatization effects during pre-milking of cows on thermal conditioning, physiology, milk production and cost-benefit of the automated adiabatic evaporative cooling system (AECS. The treatments 20; 30; 40 min and control consisted of exposure time of pre-milking cows to the automated AECS. Sixteen cows were used with an average daily milk yield of 19 kg, distributed in a 4 x 4 Latin square design. The Tukey's test (PObjetivou-se com esta pesquisa avaliar os efeitos da climatização na pré-ordenha sobre o acondicionamento térmico, fisiologia, produção de leite e relação custo/benefício do sistema de resfriamento adiabático evaporativo (SRAE automatizado. Os tratamentos adotados foram os tempos de exposição dos animais ao SRAE no curral de espera, 20; 30; 40 min e o tratamento-controle. Utilizaram-se 16 vacas com produção de 19 kg de leite dia-1, adotando-se delineamento em quadrado latino 4 x 4 e comparação entre as médias pelo teste de Tukey (P<0,05. Foram registradas as variáveis ambientais temperatura de bulbo seco (Tbs e umidade relativa (UR a cada minuto, o que permitiu determinar a eficiência do sistema por meio do índice de temperatura e umidade (ITU. A frequência respiratória (FR, temperatura retal (TR e temperatura de pelame (TP foram medidas antes e depois da climatização. O tratamento 40 min permitiu manter as variáveis ambientais e os índices de conforto entre os limites recomendados. As variáveis fisiológicas (FR, TR e TP mostraram valores inferiores no tratamento 40 min, com aumento de 3,66% na produção de leite, quando comparado com o controle. O investimento promoveu acréscimo na receita mensal de R$ 1.992,67 com tempo de retorno do capital de 43 dias.

  19. Disinfection of sewage

    International Nuclear Information System (INIS)

    Arenas, J.

    1984-01-01

    Laboratory studies at IPEN and SEDAPAL have shown the effectiveness disinfection of sewage by means of ionizing radiations. A dose of 1 Kilo Gray reduces the coliforms and salmonella under the permissible levels. This method should allow to use again the liquids in the agriculture or its disposal like sea nutrient

  20. Update on the development of a novel dry cow therapy using a bismuth-based intramammary teat seal in combination with the bacteriocin lacticin 3147

    Directory of Open Access Journals (Sweden)

    Crispie Fiona

    2004-11-01

    Full Text Available Public concerns over the widespread prophylactic use of antibiotics have led to a search for alternatives to dry cow therapy for the prevention of intramammary infections. A popular alternative is to infuse a teat seal at drying-off. The teat seal is a viscous non-antibiotic formulation and when it is infused into the teat canal and the teat sinus it forms an internal seal that provides a physical barrier to invasion by mastitis-causing pathogens. Enhancement of teat seal formulations may be achieved using non-antibiotic additives such as bacteriocins, potent proteins produced by some bacteria that have the ability to kill other microorganisms. This paper traces the history of investigations at Moorepark Research Centre into the efficacy of teat seal plus lacticin 3147, a bacteriocin produced by Lactococcus lactis DPC3147, in the prevention of intramammary infections in dry cows. Indications from on-going investigations are that a dry cow formulation combining the two products has considerable potential as a non-antibiotic prophylactic product.

  1. [Correlations between the vitality of newborn piglets, teat order, mortality, and live weight development up to weaning].

    Science.gov (United States)

    Hoy, S; Lutter, C; Puppe, B; Wähner, M

    1995-06-01

    Investigations with 693 piglets have shown, that suckling piglets with preference of cranial teat pairs were significantly superior to their littermates in all parameters of early postnatal vitality: they stood up and took in first colostrum earlier and showed a lower postnatal drop in rectal temperature in comparison with their siblings. Piglets in cranial teat position had the highest daily gain (205 g, p vitality of piglets post natum on live weight development and mortality up to 28th day of age were shown. The faster piglets took in colostrum after birth and the lower postnatal drop in rectal temperature was, the higher was the obtained daily gain during suckling period. Piglets which died within the first 7 or 28 days of age had needed a significantly longer time till first postnatal colostrum intake and a more pronounced drop in rectal temperature in comparison with their littermates.

  2. Water disinfection agents and disinfection by-products

    Science.gov (United States)

    Ilavský, J.; Barloková, D.; Kapusta, O.; Kunštek, M.

    2017-10-01

    The aim of this work is to describe factors of water quality change in the distribution network and legislative requirements in Slovakia for disinfectants and disinfection byproducts (DBPs). In the experimental part, the time dependence of the application of the chlorine dioxide and sodium hypochlorite on the formation of some by-products of disinfection for drinking water from WTP Hriňová is studied. We monitored trihalomethanes, free chlorine, chlorine dioxide and chlorites.

  3. Sewage sludges disinfection

    International Nuclear Information System (INIS)

    Alexandre, D.

    1977-01-01

    There is an hygienic risk in using biological sewage sludges for agriculture. Systematic analysis carried out on sludges samples obtained from purification plants in East and South part of France, show the almost uniform presence of pathogenic microorganisms. Some of it survive more than 9 months after soil application. Conventional process for disinfection: liming and heat are not suitable for agricultural use. On the other hand, irradiation involves no modification in structure and composition of sludges. Radiation doses required for disinfection vary according to microorganisms. If some of them are eliminated with rather light doses (200 krad) mycobacteria, viruses and eggs of worms resist to more important doses. Security dose is estimated around 1000 krad

  4. Sewage sludges disinfection

    International Nuclear Information System (INIS)

    Alexandre, D.; Gevaudan, P.P.

    1977-01-01

    There is a hygienic risk in using biological sewage sludges for agriculture. Systematic analyses carried out on sludge samples obtained from purification plants in the Eastern and Southern part of France, show the almost uniform presence of pathogenic microorganisms. Some of them survive more than nine months after application to the soil. Conventional processes for disinfection, liming and heat, make the sludge unsuitable for agricultural use. On the other hand, irradiation involves no modification of structure and composition of sludges. Radiation doses required for disinfection vary according to the type of microorganism. Some of them are eliminated at rather low doses (200 krad), but mycobacteria, viruses and eggs of worms resist to more important doses. The security dose is estimated to be approx. 1000 krad

  5. Spiral-shaped reactor for water disinfection

    KAUST Repository

    Soukane, Sofiane; Ait-Djoudi, Fariza; Naceur, Wahib M.; Ghaffour, NorEddine

    2016-01-01

    Chlorine-based processes are still widely used for water disinfection. The disinfection process for municipal water consumption is usually carried out in large tanks, specifically designed to verify several hydraulic and disinfection criteria

  6. A review on wastewater disinfection

    Directory of Open Access Journals (Sweden)

    Mohammad Mehdi Amin

    2013-01-01

    Full Text Available Changes in regulations and development of new technologies have affected the selection of alternative for treated wastewater disinfection. Disinfection is the last barrier of wastewater reclamation process to protect ecosystem safety and human health. Driving forces include water scarcity and drinking water supply, irrigation, rapid industrialization, using reclaimed water, source protection, overpopulation, and environmental protection. The safe operation of water reuse depends on effluent disinfection. Understanding the differences in inactivation mechanisms is critical to identify rate-limiting steps involved in the inactivation process as well as to develop more effective disinfection strategies. Disinfection byproducts discharged from wastewater treatment plants may impair aquatic ecosystems and downstream drinking-water quality. Numerous inorganic and organic micropollutants can undergo reactions with disinfectants. Therefore, to mitigate the adverse effects and also to enhance that efficiency, the use of alternative oxidation/disinfection systems should be evaluated as possible alternative to chlorine. This review gives a summary of the traditional, innovative, and combined disinfection alternatives and also disinfection byproducts for effluent of municipal wastewater treatment plants.

  7. Effect of dry period length on the effect of an intramammary teat sealant on the risk of mastitis in cattle treated with antibiotics at drying off.

    Science.gov (United States)

    Laven, R A; Balcomb, C C; Tulley, W T; Lawrence, K E

    2014-07-01

    The aim of this study was to evaluate, under farm conditions, the use of a teat sealant in addition to whole herd dry cow antibiotic therapy on the risk of clinical mastitis in dairy cattle at pasture, and to evaluate the impact of dry period length on that risk and the impact of the teat sealant on that risk. Dairy cows in three herds which used routine whole herd antibiotic therapy were randomly assigned to receive either treatment with an internal teat sealant (n=322) or no additional treatment (n=313) at drying-off between March and May 2010. All clinical mastitis cases during the dry period and to the end of the subsequent lactation were recorded by farm staff; factors affecting risk of clinical mastitis were then analysed using a Cox proportional hazards model. Median duration of the dry period was 112 days with >25% of cows having a dry period >130 days. The incidence risk of mastitis during lactation for cows treated with teat sealant was 9.9 (95% CI=6.9-13.7) cases per 100 cows compared with 17.9 (95% CI=13.8-22.6) cases per 100 cows for cows treated with antibiotic alone. The addition of a teat sealant to dry cow antibiotic therapy decreased the risk of clinical mastitis only in the first 33 days after calving (Hazard risk 0.24 (95% CI=0.12-0.48)). Length of dry period did not significantly affect the risk of clinical mastitis, or the effect of adding teat sealant to dry cow antibiotic therapy on the risk of clinical mastitis. In these herds where, based on the mastitis history, whole herd antibiotic therapy had been recommended, the use of a teat sealant significantly reduced the risk of clinical mastitis. This effect was limited to the first 33 days after calving; subsequently there was no significant effect of treatment. There was no effect of dry period length on risk of clinical mastitis, nor any significant interaction with treatment. Combination therapy with teat sealant and antibiotic was effective under New Zealand conditions in herds using whole

  8. Sanitizers and Disinfectants Guide. Revised

    Science.gov (United States)

    Healthy Schools Network, Inc., 2012

    2012-01-01

    Sanitizers and disinfectants can play an important role in protecting public health. They are designed to kill "pests," including infectious germs and other microorganisms such as bacteria, viruses, and fungi. Unfortunately, sanitizers and disinfectants also contain chemicals that are "pesticides." Exposure to persistent toxic…

  9. USE OF HYDROALCOHOLIC EXTRACT OF Schinus terebinthifolius Raddi IN PRE- AND POST-MILKING ANTISEPSIS OF THE TEAT IN DAIRY COWS

    Directory of Open Access Journals (Sweden)

    Ângela Faccin

    2016-01-01

    Full Text Available Medicinal plants have been used for centuries as an alternative treatment for health problems. Schinus terebinthifolius Raddi is a median tree that belongs to the Anacardiaceae family. The antibacterial effect of leaves extract of this plant has already been demonstrated. The objective of this study was to test a substance derived from this plant to be used in pre- and post-milking teat antisepsis. The hydroalcoholic extract of Brazilian pepper tree was used in opposite quarters for twelve consecutive weeks, and commercial iodine was used as control. None of the indices analyzed – black background mug, CMT, intramammary infections, skin health, and teat health – showed a statistical difference between the treatments, suggesting that the plant extract can be used in pre- and post-milking teat antisepsis, as a substitute for conventional products for herds in an agroecological production system.

  10. 40 CFR 141.72 - Disinfection.

    Science.gov (United States)

    2010-07-01

    ... PRIMARY DRINKING WATER REGULATIONS Filtration and Disinfection § 141.72 Disinfection. A public water... the direct influence of surface water and provides filtration treatment must provide disinfection...) Disinfection requirements for public water systems which provide filtration. Each public water system that...

  11. Ultraviolet disinfection of potable water

    Energy Technology Data Exchange (ETDEWEB)

    Wolfe, R. L. [Metropolitan Water District of Southern California, Los Angeles, CA (United States)

    1990-06-15

    Because of upcoming surface and groundwater regulations regarding the control of microbiological and chemical contaminants, there is a need to evaluate the feasibility and effectiveness of ultraviolet (UV) radiation for primary disinfection of potable water supplies. Data is presented on microbicidal wavelengths of UV and distribution of energy output for low and medium-pressure arc lamps. Both systems were found to perform equally well for inactivating microorganisms, but each had distinct advantages in different applications. Approximate dosages for 90% inactivation of selected microorganisms by UV is presented in a table. Cost analysis for disinfection is presented in two tables as well as the advantages and disadvantages of UV disinfection.

  12. Ultraviolet disinfection of potable water

    International Nuclear Information System (INIS)

    Wolfe, R.L.

    1990-01-01

    Because of upcoming surface and groundwater regulations regarding the control of microbiological and chemical contaminants, there is a need to evaluate the feasibility and effectiveness of ultraviolet (UV) radiation for primary disinfection of potable water supplies. Data is presented on microbicidal wavelengths of UV and distribution of energy output for low and medium-pressure arc lamps. Both systems were found to perform equally well for inactivating microorganisms, but each had distinct advantages in different applications. Approximate dosages for 90% inactivation of selected microorganisms by UV is presented in a table. Cost analysis for disinfection is presented in two tables as well as the advantages and disadvantages of UV disinfection

  13. A review on wastewater disinfection

    OpenAIRE

    Mohammad Mehdi Amin; Hassan Hashemi; Amir Mohammadi Bovini; Yung Tse Hung

    2013-01-01

    Changes in regulations and development of new technologies have affected the selection of alternative for treated wastewater disinfection. Disinfection is the last barrier of wastewater reclamation process to protect ecosystem safety and human health. Driving forces include water scarcity and drinking water supply, irrigation, rapid industrialization, using reclaimed water, source protection, overpopulation, and environmental protection. The safe operation of water reuse depends on effluent d...

  14. Efficacy of an internal teat seal associated with a dry cow intramammary antibiotic for prevention of intramammary infections in dairy cows during the dry and early lactation periods

    Directory of Open Access Journals (Sweden)

    Lívio R. Molina

    Full Text Available ABSTRACT: The present study aimed to evaluate the use of an internal dry period teat seal containing bismuth subnitrate (Teatseal®, Zoetis®, Florham Park, Nova Jersey, USA associated with a long-acting cloxacilin preparation (Orbenin® Extra dry cow, Zoetis®, Florham Park, Nova Jersey, USA, in preventing new infections during the dry-off and early postpartum period. A total of 150 Holstein cows (average production of 9,000 kg of milk per lactation, with four functional udder quarters without clinical mastitis was included in the study. All animals were dried-off 60 days before the expected calving date. Two teats positioned diagonal-contralaterally received only dry cow antibiotic, control group C (n=300 and the other two teats, treatment group T (n=300 received dry cow antibiotic and infusion with an internal teat seal. Data from SCC variable were transformed by log base-10 transformation. Duncan’s test was used accepting 5% as the level of statistical significance. The occurrence of intramammary infection (IMI and chronicity rate, and frequency of microorganisms isolated at drying and immediately postpartum in teats of group C and group T were evaluated using a non-parametric Chi-square Test, accepting 10% as the statistical significance level. There was a decrease in the occurrence of new infections in the early postpartum in cows which the sealant was used (C=19.6%, T=11.4%. In the postpartum period, Gram-negative bacteria were isolated from 16 teats in C and seven in T. The greatest reduction was observed for Escherichia coli (8 vs 1 in group T. There was no effect using the internal sealant on the frequency of isolation of environmental Streptococus. The use of sealant reduced the prevalence of subclinical mastitis cows between drying-off and the early postpartum period (C=51% versus T=42% and resulted in a lower somatic cell count (SCC in the treatment group when compared with the control group (T=1,073x103, C=1,793x103. The use of

  15. Low cost driver device for microclimate maintenance in the pre-milking of dairy cattle Dispositivo controlador de baixo custo para a manutenção do microclima na pré-ordenha de bovinos leiteiros

    Directory of Open Access Journals (Sweden)

    Irenilson M. da Silva

    2013-02-01

    Full Text Available Due to the importance of the environment on animal production and thus environmental control, the study aims to build a system for monitoring and control the meteorological variables, temperature and relative humidity, low cost, which can be associated with an evaporative cooling system (ECS. The system development included all the stages of assembly, test and laboratory calibration, and later the validation of the equipment carried in the field. The validation step showed results which allowed concluding that the system can be safely used in the monitoring of these variables. The controller was efficient in management of the microclimate in the waiting corral and allowed the maintenance of the air temperature within the comfort range for dairy cattle in pre-milking with averaged 25.09 ºC during the afternoon. The equipment showed the lower cost (R$ 325.76 when compared to other middle market (R$ 450.00.Devido à importância do ambiente na produção animal e, portanto, do controle ambiental adequado, objetivou-se com este trabalho a construção de um sistema de monitoramento e controle das variáveis meteorológicas, temperatura e umidade relativa do ar, de baixo custo, associado a um sistema de resfriamento adiabático evaporativo (SRAE. O desenvolvimento do sistema controlador compreendeu as etapas de montagem, teste e aferição em laboratório e, posteriormente, a etapa de validação do equipamento realizada a campo. A etapa de validação apresentou resultados que permitiram concluir que o sistema pode ser utilizado com segurança no monitoramento e controle dessas variáveis por meio dos atuadores. O controlador mostrou-se eficiente no manejo do microclima no curral de espera e permitiu a manutenção da temperatura do ar dentro da faixa de conforto para bovinos leiteiros na pré-ordenha, apresentando média de 25,09 ºC durante o turno da tarde. O equipamento apresentou custo inferior (R$ 325,76 quando comparado à média de outros

  16. Environmentally friendly disinfectant: Production, disinfectant action and efficiency

    Directory of Open Access Journals (Sweden)

    Čekerevac Milan I.

    2006-01-01

    Full Text Available Silver is a known disinfectant from ancient times, and it has been widely used for various purposes: for food and water disinfection, curing of wounds and as a universal antibiotic for a wide spectrum of diseases - until the Second World War and the discovery of penicillin. Until recently, it was assumed that silver, being a heavy metal, was toxic for humans and living beings. However, the newest research provides facts that the usage of silver, even for drinking water disinfection, is benign if it is added in small concentrations (in parts per billion. It has been shown in the newer scientific and technical literature that silver in colloidal form is a powerful (secondary disinfectant for drinking water, that it can be effectively used for the disinfection of water containers including swimming pools, installations in food industry, medicine, etc. Particularly, it has been shown that colloidal silver combined with hydrogen peroxide shows synergism having strong bactericidal and antiviral effects. The combination can be successfully used as a disinfectant in agriculture, food production and medicine. The original electrochemical process of production, the mechanism of physical-chemical reactions in that process and the mechanism of the antiseptic affect of the environmentally friendly disinfectant, based on the synergism of colloidal silver and hydrogen peroxide and the activity of electrochemically activated water, is shown. The starting solution was anolyte, obtained in electrochemical activation by water electrolysis of a highly diluted solution of K-tartarate in demineralized water (5.5-1CT4 M. The problem of electrolysis of very dilute aqueous solutions in membrane cells was particularly treated. It was shown that the efficiency of the electrolysis depends on the competition between the two processes: the rates of the processes of hydrogen and oxygen generation at the electrodes and the process of diffusion of hydrogen and hydroxyl ions

  17. [DESIDENT CaviCide a new disinfectant].

    Science.gov (United States)

    Severa, J; Klaban, V

    2009-01-01

    The properties of the new disinfection agent DESIDENT CaviCide, such as characteristics, disinfection efficiency, biological degradability and ecotoxicity are described. Also areas and forms of usage this biocidal agent are mentioned.

  18. Associations of soft flooring materials in free stalls with milk yield, clinical mastitis, teat lesions, and removal of dairy cows.

    Science.gov (United States)

    Ruud, L E; Bøe, K E; Osterås, O

    2010-04-01

    The objective was to test if there was an association between free-stall base softness and milk yield, incidence of clinical mastitis (CM), teat lesions, and removal of cows. In a questionnaire sent to 1,923 dairy farms presumed to be using free-stall housing, farmers were asked for information regarding housing and stall base; for example, the year of installation and the product name or brand of their mats or mattresses. This information was merged with data for milk yield, CM, teat lesions, and removal of cows extracted from the Norwegian Dairy Herd Recording System for the years after installation of mats or mattresses. After exclusion of invalid contributions, the data set consisted of 29,326 lactations for milk yield distributed over 363 free-stalled herds in Norway. The farms were stratified into 5 categories according to the softness of the stall surface measured as millimeter impact of a sphere with a diameter of 120 mm at 2-kN load: 1=concrete, softness of 0mm; 2=rubber, softness of 1 to 8mm; 3=soft mats, softness of 9 to 16 mm; 4=multilayer mats, softness of 17 to 24 mm; and 5=mattresses, softness over 24 mm. Lactation curves were estimated as modified Wood's lactation curves using test-day data and mixed models with repeated measurements, adjusting for days in milk, parity, and softness of free-stall flooring. Herds on concrete free-stall bases yielded 6,727+/-146 kg of milk from 5 to 305 days in milk. In comparison, herds showed a decrease of 0.3% on rubber, an increase of 2.4% on soft mats, an increase of 4.5% on multilayer mats, and an increase of 3.9% on mattresses. Compared with concrete, the hazard ratio (HR) of CM was less on rubber, multilayer mats, and mattresses [HR=0.89 (0.79-0.99), 0.85 (0.73-0.996), and 0.80 (0.73-0.88), respectively]. Compared with concrete, the HR of teat lesions was less on rubber, soft mats, multilayer mats, and mattresses [HR=0.41 (0.26-0.65), 0.33 (0.24-0.44), 0.12 (0.04-0.38), and 0.47 (0.33-0.67), respectively]. The

  19. Estimating retrospective exposure of household humidifier disinfectants.

    Science.gov (United States)

    Park, D U; Friesen, M C; Roh, H S; Choi, Y Y; Ahn, J J; Lim, H K; Kim, S K; Koh, D H; Jung, H J; Lee, J H; Cheong, H K; Lim, S Y; Leem, J H; Kim, Y H; Paek, D M

    2015-12-01

    We conducted a comprehensive humidifier disinfectant exposure characterization for 374 subjects with lung disease who presumed their disease was related to humidifier disinfectant use (patient group) and for 303 of their family members (family group) for an ongoing epidemiological study. We visited the homes of the registered patients to investigate disinfectant use characteristics. Probability of exposure to disinfectants was determined from the questionnaire and supporting evidence from photographs demonstrating the use of humidifier disinfectant, disinfectant purchase receipts, any residual disinfectant, and the consistency of their statements. Exposure duration was estimated as cumulative disinfectant use hours from the questionnaire. Airborne disinfectant exposure intensity (μg/m(3)) was estimated based on the disinfectant volume (ml) and frequency added to the humidifier per day, disinfectant bulk level (μg/ml), the volume of the room (m(3)) with humidifier disinfectant, and the degree of ventilation. Overall, the distribution patterns of the intensity, duration, and cumulative exposure to humidifier disinfectants for the patient group were higher than those of the family group, especially for pregnant women and patients ≤6 years old. Further study is underway to evaluate the association between the disinfectant exposures estimated here with clinically diagnosed lung disease. Retrospective exposure to household humidifier disinfectant as estimated here can be used to evaluate associations with clinically diagnosed lung disease due to the use of humidifier disinfectant in Korea. The framework, with modifications to account for dispersion and use patterns, can also be potentially adapted to assessment of other household chemical exposures. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  20. Microbiological Efficacy Test Methods of Disinfectants

    OpenAIRE

    Şahiner, Aslı

    2015-01-01

    Disinfection process is required in every area where microbiological contamination and infection risk is present, especially in medical sector, food, veterinary and general common living areas hence many disinfectants and antiseptics are being produced for different purposes. Disinfectants are made up a large group of biocidal products. Depending on the chemical properties of active substances, targeted microorganisms may differ While some disinfectants are effective in a large spectrum, othe...

  1. UV disinfection in drinking water supplies.

    Science.gov (United States)

    Hoyer, O

    2000-01-01

    UV disinfection has become a practical and safely validatable disinfection procedure by specifying the requirements for testing and monitoring in DVGW standard W 294. A standardized biodosimetric testing procedure and monitoring with standardized UV sensors is introduced and successfully applied. On-line monitoring of irradiance can be counterchecked with handheld reference sensors and makes it possible that UV systems can be used for drinking water disinfection with the same level of confidence and safety as is conventional chemical disinfection.

  2. Can pulsed xenon ultraviolet light systems disinfect aerobic bacteria in the absence of manual disinfection?

    Science.gov (United States)

    Jinadatha, Chetan; Villamaria, Frank C; Ganachari-Mallappa, Nagaraja; Brown, Donna S; Liao, I-Chia; Stock, Eileen M; Copeland, Laurel A; Zeber, John E

    2015-04-01

    Whereas pulsed xenon-based ultraviolet light no-touch disinfection systems are being increasingly used for room disinfection after patient discharge with manual cleaning, their effectiveness in the absence of manual disinfection has not been previously evaluated. Our study indicates that pulsed xenon-based ultraviolet light systems effectively reduce aerobic bacteria in the absence of manual disinfection. These data are important for hospitals planning to adopt this technology as adjunct to routine manual disinfection. Published by Elsevier Inc.

  3. USE OF HYDROALCOHOLIC EXTRACT OF Schinus terebinthifolius Raddi IN PRE- AND POST-MILKING ANTISEPSIS OF THE TEAT IN DAIRY COWS

    OpenAIRE

    Faccin, Ângela; Schuch, Luiz Filipe Damé; Schiavon, Diane Bender Almeida; Gonçalves, Carolina Lambrecht; Mota, Fernanda Voight; Lessa, Lisiane Ferreira

    2016-01-01

    Abstract Medicinal plants have been used for centuries as an alternative treatment for health problems. Schinus terebinthifolius Raddi is a median tree that belongs to the Anacardiaceae family. The antibacterial effect of leaves extract of this plant has already been demonstrated. The objective of this study was to test a substance derived from this plant to be used in pre- and post-milking teat antisepsis. The hydroalcoholic extract of Brazilian pepper tree was used in opposite quarters for ...

  4. Antibacterial activities of coagulase-negative staphylococci from bovine teat apex skin and their inhibitory effect on mastitis-related pathogens.

    Science.gov (United States)

    Braem, G; Stijlemans, B; Van Haken, W; De Vliegher, S; De Vuyst, L; Leroy, F

    2014-05-01

    To explore antibacterial activities of coagulase-negative staphylococci (CoNS) from teat apices of dairy cows towards mastitis-causing pathogens. Of 254 CoNS, 38 displayed bacteriocin-like activity after a first screening. Seven of these strains displayed activity against at least one mastitis-related pathogen (Streptococcus uberis, Streptococcus dysgalactiae and Staphylococcus aureus). Staphylococcus chromogenes L217 displayed the strongest inhibitory effect, being active against all tested mastitis-related pathogens and most tested CoNS. Based on cation exchange and reversed-phase chromatography, in addition to N-terminal Edman degradation and PCR, the antibacterial peptide was identified as a nukacin-type bacteriocin and named nukacin L217. Although staphylococcal bacteriocins are generally found in the cell-free supernatants of liquid cultures, Staph. chromogenes L217 only led to detectable activity when grown on agar medium. Bacteriocin-like activities are not uncommon among CoNS from teat apices and may inhibit mastitis-causing pathogens, as found for nukacin L217 production by Staph. chromogenes L217. Nukacin L217 is the first identified bacteriocin of the species Staph. chromogenes and displays unusual production kinetics, that is, requiring surface growth of its producer. The fact that nukacins are produced by different CoNS species suggests a role in the teat skin ecosystem. © 2014 The Society for Applied Microbiology.

  5. Improving stethoscope disinfection at a children's hospital.

    Science.gov (United States)

    Zaghi, Justin; Zhou, Jing; Graham, Dionne A; Potter-Bynoe, Gail; Sandora, Thomas J

    2013-11-01

    Stethoscopes are contaminated with pathogenic bacteria and pose a risk for transmission of infections, but few clinicians disinfect their stethoscope after every use. We sought to improve stethoscope disinfection rates among pediatric healthcare providers by providing access to disinfection materials and visual reminders to disinfect stethoscopes. Prospective intervention study. Inpatient units and emergency department of a major pediatric hospital. Physicians and nurses with high anticipated stethoscope use. Baskets filled with alcohol prep pads and a sticker reminding providers to regularly disinfect stethoscopes were installed outside of patient rooms. Healthcare providers' stethoscope disinfection behaviors were directly observed before and after the intervention. Multivariable logistic regression models were created to identify independent predictors of stethoscope disinfection. Two hundred twenty-six observations were made in the preintervention period and 261 in the postintervention period (83% were of physicians). Stethoscope disinfection compliance increased significantly from a baseline of 34% to 59% postintervention (P stethoscope disinfection supplies and visible reminders outside of patient rooms significantly increased stethoscope disinfection rates among physicians and nurses at a children's hospital. This simple intervention could be replicated at other healthcare facilities. Future research should assess the impact on patient infections.

  6. An observational cohort study on persistency of internal teat sealant residues in milk after calving in dairy cows.

    Science.gov (United States)

    Kabera, Fidèle; Dufour, Simon; Keefe, Greg; Roy, Jean-Philippe

    2018-04-04

    Our objectives were to evaluate the prevalence of quarters with an observable internal teat sealant (ITS) plug at first milking following calving and investigate persistency of ITS residues in milk after calving. An observational cohort study was carried out on 557 quarters of 156 cows treated with ITS in 6 farms in Quebec, Canada. The presence of an ITS plug at first milking and ITS residues in milk at each milking were observed by producers. The effects of various factors on the odds of observing an ITS plug and persistency of ITS residues in milk were studied using generalized logistic mixed and generalized negative binomial mixed models, respectively. Milk samples were taken on the day before dry-off and on 2 occasions after calving for bacterial identification to detect intramammary infection (IMI) using bacteriological culture followed by MALDI-TOF identification. The association between the absence of an ITS plug and the presence of new IMI was assessed using a mixed logistic regression model. Internal teat sealant plugs after calving were more often observed in rear quarters and in quarters receiving ITS alone at drying-off versus antimicrobial and ITS. We observed an average (standard deviation) persistency of 4.0 d (2.3 d). When an ITS plug was still present at first milking (83% of quarters), the elimination of ITS residues in milk after calving was significantly longer (4.5 d, on average) compared with 1.2 d when an ITS plug was absent. In cows with an ITS plug at calving, we observed a higher number of days of excretion in older cows. When a plug could not be observed, rear quarters, older cows, and cows with a long dry period duration excreted ITS residues for a significantly longer period. The lack of a significant association between the absence of a plug and the odds of new IMI at calving suggests that despite the loss of the plug, cows were still protected against new IMI. Although we were able to highlight some statistically significant risk

  7. DISINFECTION BY-PRODUCT FORMATION BY ALTERNATIVE DISINFECTANTS AND REMOVAL BY GRANULAR ACTIVATED CARBON

    Science.gov (United States)

    The effects of the use of the alternative disinfectants on the formation of halogenated disinfection by–products (DBPs) including total organic halide, trihalomethanes, haloacetic acids, haloacetonitriles, haloketones, chloral hydrate, and chloropicrin, were examined along ...

  8. Zinc oxide nanoparticles for water disinfection

    Directory of Open Access Journals (Sweden)

    Emelita Asuncion S. Dimapilis

    2018-03-01

    Full Text Available The world faces a growing challenge for adequate clean water due to threats coming from increasing demand and decreasing supply. Although there are existing technologies for water disinfection, their limitations, particularly the formation of disinfection-by-products, have led to researches on alternative methods. Zinc oxide, an essential chemical in the rubber and pharmaceutical industries, has attracted interest as antimicrobial agent. In nanoscale, zinc oxide has shown antimicrobial properties which make its potential great for various applications. This review discusses the synthesis of zinc oxide with focus on precipitation method, its antimicrobial property and the factors affecting it, disinfection mechanisms, and the potential application to water disinfection.

  9. An environmental disinfection odyssey: evaluation of sequential interventions to improve disinfection of Clostridium difficile isolation rooms.

    Science.gov (United States)

    Sitzlar, Brett; Deshpande, Abhishek; Fertelli, Dennis; Kundrapu, Sirisha; Sethi, Ajay K; Donskey, Curtis J

    2013-05-01

    OBJECTIVE. Effective disinfection of hospital rooms after discharge of patients with Clostridium difficile infection (CDI) is necessary to prevent transmission. We evaluated the impact of sequential cleaning and disinfection interventions by culturing high-touch surfaces in CDI rooms after cleaning. DESIGN. Prospective intervention. SETTING. A Veterans Affairs hospital. INTERVENTIONS. During a 21-month period, 3 sequential tiered interventions were implemented: (1) fluorescent markers to provide monitoring and feedback on thoroughness of cleaning facility-wide, (2) addition of an automated ultraviolet radiation device for adjunctive disinfection of CDI rooms, and (3) enhanced standard disinfection of CDI rooms, including a dedicated daily disinfection team and implementation of a process requiring supervisory assessment and clearance of terminally cleaned CDI rooms. To determine the impact of the interventions, cultures were obtained from CDI rooms after cleaning and disinfection. RESULTS. The fluorescent marker intervention improved the thoroughness of cleaning of high-touch surfaces (from 47% to 81% marker removal; P disinfection, whereas during interventions periods 1, 2, and 3 the percentages of CDI rooms with positive cultures after disinfection were reduced to 57%, 35%, and 7%, respectively. CONCLUSIONS. An intervention that included formation of a dedicated daily disinfection team and implementation of a standardized process for clearing CDI rooms achieved consistent CDI room disinfection. Culturing of CDI rooms provides a valuable tool to drive improvements in environmental disinfection.

  10. Anaerobic effluent disinfection using ozone: Byproducts formation

    NARCIS (Netherlands)

    Silva, G.H.R.; Daniel, L.A.; Bruning, H.; Rulkens, W.H.

    2010-01-01

    This research was aimed at studying oxidation processes, coliform inactivation effectiveness and disinfection byproducts (DBPs) associated with the disinfection of anaerobic sanitary wastewater effluent with ozone applied at doses of 5.0, 8.0 and 10.0mg O(3)L(-1) for contact times of 5, 10 and 15

  11. Ultraviolet (UV) Disinfection for Drinking Water Systems

    Science.gov (United States)

    UV disinfection is an effective process for inactivating many microbial pathogens in water with potential to serve as stand-alone treatment or in combination with other disinfectants. USEPA provided guidance on the validation of UV reactors nearly a decade ago. Since then, lesson...

  12. Silver disinfection in water distribution systems

    Science.gov (United States)

    Silvestry Rodriguez, Nadia

    Silver was evaluated as disinfectant to maintain water quality in water distribution system. It was used to inhibit growth of two opportunistic bacteria in planktonik form and in biofilm formation in Robbins devices with stainless steel and PVC surfaces. The results of this work show that silver is a potential secondary disinfectant to be used in water distribution systems.

  13. Chemical disinfection of combined sewer overflows

    DEFF Research Database (Denmark)

    Chhetri, Ravi Kumar

    of the residual disinfectants PFA, PAA and chlorine dioxide (ClO2), and their degradation products hydrogen peroxide and chlorite, in relation to organisms in the aquatic ecosystem was studied. With the help of ecotoxicity data, a preliminary environmental risk assessment of PFA, PAA and ClO2 for CSO disinfection...

  14. Adaptive Mechanisms Underlying Microbial Resistance to Disinfectants

    Science.gov (United States)

    2016-02-01

    11775]). E.coli is a gram-negative, facultative anaerobic, and rod-shaped bacteria commonly found in warm-blooded animals . 2.1.2 Disinfectants...Nisbet, D.J. Disinfectant and Antibiotic Susceptibility Profiles of Escherichia coli O157:H7 Strains from Cattle Carcasses , Feces, and Hides and

  15. Effects of alternative deep bedding options on dairy cow preference, lying behavior, cleanliness, and teat end contamination.

    Science.gov (United States)

    Wolfe, T; Vasseur, E; DeVries, T J; Bergeron, R

    2018-01-01

    Cows spend more time lying down when stalls are soft and dry, and bedding plays a key role in the comfort of the lying surface. The first objective of this study (experiment 1) was to compare cow preference for 2 types of alternative deep-bedding materials, switchgrass and switchgrass-lime, using wheat straw on a rubber mat as a control. Nine Holstein lactating cows were submitted in trios to a 3-choice preference test over 14 d (2 d of adaptation, 3 d of restriction to each stall, and 3 d of free access to all 3 stalls). Cows were housed individually in pens containing 3 stalls with different lying surfaces: (1) rubber mat with chopped wheat straw (WS); (2) deep-bedded switchgrass (SG); and (3) deep-bedded switchgrass, water, and lime mixture (SGL). The second objective (experiment 2) was to test, in freestall housing, the effects of these 3 types of bedding on lying behavior, cow cleanliness, and teat end bacterial contamination. Bedding treatments were compared in a 3 × 3 Latin square design using 24 cows split into groups of 8, with bedding materials being switched every 4 wk. Lying behavior was measured with data loggers in both studies. During experiment 1, cows chose to spend more time lying and had more frequent lying bouts on SG (9.4 h/d; 8.2 bouts/d) than on SGL (1.0 h/d; 0.9 bouts/d). They also spent more time standing and stood more frequently in stalls with SG (2.0 h/d; 10.1 bouts/d) than in those with SGL (0.6 h/d; 2.6 bouts/d), and stood longer in stalls with SG than with WS (0.6 h/d). In experiment 2, the total lying time, frequency of lying bouts, and mean lying bout duration were, on average, 9.7 ± 1.03 h/d, 8.2 ± 0.93 bouts/d, and 1.2 ± 0.06 h/bout, respectively, and did not differ between treatments. No treatment effects were found for cow cleanliness scores. Bedding dry matter was highest for SG (74.1%), lowest for SGL (63.5%), and intermediate for WS (68.6%) [standard error of the mean (SEM) = 1.57%]. This may explain the higher teat end

  16. Análise espacial das condições térmicas do ambiente pré-ordenha de bovinos leiteiros sob regimes de climatização Spatial analysis of thermal conditions of the pre-milking dairy cattle under climatization regimes

    Directory of Open Access Journals (Sweden)

    Irenilson M. da Silva

    2012-08-01

    Full Text Available Propõe-se, com este trabalho, caracterizar a variabilidade espacial da temperatura do ar na sala de pré-ordenha a partir de diferentes tempos de operação do sistema de resfriamento adiabático evaporativo automatizado. A variável temperatura do ar foi registrada em 35 pontos equidistantes 1 m, na forma de malha, para o estudo da variabilidade espacial e a construção de mapas por krigagem. Foram considerados diferentes tempos de exposição dos animais a climatização no curral de espera, 20, 30, 40 min e controle (0 min. Por meio dos resultados obtidos foi possível verificar que o uso da geoestatística possibilitou definir áreas com diferentes variabilidades espaciais para temperatura do ar, definindo áreas específicas na sala de pré-ordenha que apresentaram valores acima do recomendado para o conforto térmico animal. O sistema de climatização garantiu melhor acondicionamento térmico no tempo de exposição de 40 min, obtendo temperatura média dentro da condição de conforto térmico para vacas em lactação.The objective of this study was to characterize the spatial variability of air temperature in pre-milking room for different operation times of the automated adiabatic evaporative cooling system. The air temperature was monitored at 35 points, in regular intervals of 1 m, as a grid, to study the spatial variability and construction of kriging maps. Different times of exposure of the animals to the cooling system in the waiting room (20, 30, 40 min and control - 0 min were considered. Through the results, it was observed that use of geostatistics enabled to define areas with different spatial variability for temperature, identifying specific areas in the pre-milking room that showed values above the recommended levels for the thermal comfort. The cooling system ensured the better thermal condition with the 40 min exposure, obtaining on average temperature within the thermal comfort condition for lactating cows.

  17. Cleaning and Disinfection of Bacillus cereus Biofilm.

    Science.gov (United States)

    Deal, Amanda; Klein, Dan; Lopolito, Paul; Schwarz, John Spencer

    2016-01-01

    Methodology has been evolving for the testing of disinfectants against bacterial single-species biofilms, as the difficulty of biofilm remediation continues to gain much-needed attention. Bacterial single-species biofilm contamination presents a real risk to good manufacturing practice-regulated industries. However, mixed-species biofilms and biofilms containing bacterial spores remain an even greater challenge for cleaning and disinfection. Among spore-forming microorganisms frequently encountered in pharmaceutical manufacturing areas, the spores of Bacillus cereus are often determined to be the hardest to disinfect and eradicate. One of the reasons for the low degree of susceptibility to disinfection is the ability of these spores to be encapsulated within an exopolysachharide biofilm matrix. In this series of experiments, we evaluated the disinfectant susceptibility of B. cereus biofilms relative to disassociated B. cereus spores and biofilm from a non-spore-forming species. Further, we assessed the impact that pre-cleaning has on increasing that susceptibility. Methodology has been evolving for the testing of disinfectants against bacterial single-species biofilms, as the difficulty of biofilm remediation continues to gain much-needed attention. Bacterial single-species biofilm contamination presents a real risk to good manufacturing practice-regulated industries. However, mixed-species biofilms and biofilms containing bacterial spores remain an even greater challenge for cleaning and disinfection. Among spore-forming microorganisms frequently encountered in pharmaceutical manufacturing areas, the spores of Bacillus cereus are often determined to be the hardest to disinfect and eradicate. One of the reasons for the low degree of susceptibility to disinfection is the ability of these spores to be encapsulated within an exopolysachharide biofilm matrix. In this series of experiments, we evaluated the disinfectant susceptibility of B. cereus biofilms relative to

  18. 9 CFR 166.14 - Cleaning and disinfecting.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Cleaning and disinfecting. 166.14... AGRICULTURE SWINE HEALTH PROTECTION SWINE HEALTH PROTECTION General Provisions § 166.14 Cleaning and disinfecting. (a) Disinfectants to be used. Disinfection required under the regulations in this Part shall be...

  19. 9 CFR 83.7 - Shipping containers; cleaning and disinfection.

    Science.gov (United States)

    2010-01-01

    ... HEMORRHAGIC SEPTICEMIA § 83.7 Shipping containers; cleaning and disinfection. (a) All live fish that are to be... been cleaned and disinfected. (1) Cleaning and disinfection of shipping containers must be monitored by... who issues the ICI. (2) Cleaning and disinfection must be sufficient to neutralize any VHS virus to...

  20. Surface Disinfections: Present and Future

    Directory of Open Access Journals (Sweden)

    Matteo Saccucci

    2018-01-01

    Full Text Available The propagation of antibiotic resistance increases the chances of major infections for patients during hospitalization and the spread of health related diseases. Therefore finding new and effective solutions to prevent the proliferation of pathogenic microorganisms is critical, in order to protect hospital environment, such as the surfaces of biomedical devices. Modern nanotechnology has proven to be an effective countermeasure to tackle the threat of infections. On this note, recent scientific breakthroughs have demonstrated that antimicrobial nanomaterials are effective in preventing pathogens from developing resistance. Despite the ability to destroy a great deal of bacteria and control the outbreak of infections, nanomaterials present many other advantages. Moreover, it is unlikely for nanomaterials to develop resistance due to their multiple and simultaneous bactericidal mechanisms. In recent years, science has explored more complex antimicrobial coatings and nanomaterials based on graphene have shown great potential in antibacterial treatment. The purpose of this article is to deepen the discussion on the threat of infections related to surface disinfection and to assess the state of the art and potential solutions, with specific focus on disinfection procedures using nanomaterials.

  1. Sonochemical disinfection of municipal wastewater

    International Nuclear Information System (INIS)

    Antoniadis, Apostolos; Poulios, Ioannis; Nikolakaki, Eleni; Mantzavinos, Dionissios

    2007-01-01

    The application of high intensity, low frequency ultrasound for the disinfection of simulated and septic tank wastewaters is evaluated in this work. Laboratory scale experiments were conducted at 24 and 80 kHz ultrasound frequency with horn-type sonicators capable of operating in continuous and pulsed irradiation modes at nominal ultrasound intensities up to 450 W. For the experiments with simulated wastewaters, Escherichia coli were used as biological indicator of disinfection efficiency, while for the experiments with septic tank wastewaters, the total microbiological load was used. Complete elimination of E. coli could be achieved within 20-30 min of irradiation at 24 kHz and 450 W with the efficiency decreasing with decreasing intensity and frequency. Moreover, continuous irradiation was more effective than intermittent treatment based on a common energy input. Irradiation of the septic tank effluent prior to biological treatment at 24 kHz and 450 W for 30 min resulted in a three-log total microbiological load reduction, and this was nearly equal to the reduction that could be achieved during biological treatment. Bacterial cell elimination upon irradiation was irreversible as no reappearance of the microorganisms occurred after 24 h

  2. Ultraviolet disinfection of treated municipal wastewaters

    Energy Technology Data Exchange (ETDEWEB)

    Vander Laan, H; Cairns, B

    1993-12-31

    A wastewater disinfection system developed by a Canadian company, Trojan Technologies Inc., was discussed. Disinfection for pathogen reduction prior to discharge of treated municipal wastewater back into rivers and lakes has been either ignored or treated by the use of chemicals. In 1979 the first pilot ultraviolet (UV) wastewater disinfection system was established. Since then, over 500 municipal UV installations have been commissioned. The largest installation can process 212 million gallons of water per day. The advantages of UV as a disinfectant are: (1) It is more effective than chlorine. (2) There are no mutagenic/carcinogenic byproducts formed with UV. (3) No toxic chemical residuals are discharged. (4) UV is safe to both the operators and the public. (5) It is cost effective. Europe has not been as active in wastewater disinfection as has North America. One result of the absence of wastewater disinfection in Europe is that the Rhine River, for example, carries 50 million salmonella per second. Disinfection of wastewater effluents is, of course, indispensable in protecting our drinking water supply. 2 figs.

  3. Effectiveness of Dry Cow Therapy Comprising Antibiotic Treatment, Internal Teat Sealant, and α-Tocopherol Against New Intramammary Infections in Cows

    Directory of Open Access Journals (Sweden)

    Cengiz Mehmet

    2015-04-01

    Full Text Available The aim of this study was to evaluate the preventive effectiveness of dry cow therapy based on antibiotic, internal teat sealant, and α-tocopherol administered separately or in various combinations at drying-off The study was performed on 322 uninfected quarters of 95 cows originating from three dairy herds. The new intramammary infection rates after calving were measured to evaluate the effectiveness. The quarters were divided into six groups differing in treatment, namely: control group (group C, n = 40 and five treatment groups. Treatment groups were arranged as follows: group A (antibiotic alone, n = 81, group AS (antibiotic + sealant, n = 40, group AST (antibiotic + sealant + α-tocopherol, n = 40, group T (α-tocopherol alone, n = 40, group S (sealant alone, n = 81. New infection rate amounted to 47.5% in group C. The treatment in group AST significantly prevented from the occurrence of new intramammary infections (12.5%, P 0.05, although the use of the sealant alone (group S decreased the risk of new infection (24.7%, P 0.05. Increased α-tocopherol level (P < 0.05 was detected after calving in the quarters from cows that received α-tocopherol injections. In conclusion, the combination of antibiotic, internal teat sealant, and α-tocopherol used in dry cow therapy showed a significantly better preventive effect against new intramammary infections, than the therapeutics administered separately.

  4. Copper disinfection ban causes storm.

    Science.gov (United States)

    Lester, Alan

    2013-05-01

    Since 1 February this year, under the EU's Biocidal Products Directive, it has been illegal to sell or use water treatment systems that use elemental copper, a practice employed historically by a significant number of UK healthcare facilities to combat Legionella. Alan Lester, managing director of specialist supplier of 'environmentally-friendly' water treatment systems, Advanced Hydro, says the ban has caused 'a storm of giant proportion,' with advocates of copper ion-based treatment systems arguing that this disinfection method dates back 3,000 years to Egyptian times, making it an 'undoubtedly proven' technology. Here he explains why the ban came into force, considers why the UK's Health and Safety Executive (HSE) is seeking a derogation, looks at the ban's likely impact, and gives a personal viewpoint on the 'pros and cons' of some of the alternative treatment technologies, including a titanium dioxide-based system marketed by Advanced Hydro itself in the UK.

  5. Herd characteristics and management practices associated with bulk tank milk quality of dairy herds in southeastern Brazil.

    Science.gov (United States)

    Cortinhas, Cristina Simões; Botaro, Bruno Garcia; de Macedo, Susana Nori; Dos Santos, Marcos Veiga

    2018-04-30

    This study identified the association of management practices and herd characteristics with milk quality of bulk tanks in southeastern, Brazil. Milk samples were collected weekly during 8 weeks from 63 dairy herds. Bulk tanks were evaluated for total bacteria (TBC), preliminary incubation (PIC), pasteurization (PC), coliform (CC), and somatic cell counts (SCC). Associations found were type of milking system utilized in the farm with TBC, PIC, and SCC; the use of gloves for milking with TBC and PIC; sanitation of milking equipment prior to milking with PC and CC; strip cup testing of cows with PC; teat washing prior to milking with SCC; pre-milking teat disinfection with TBC and CC; post-dipping with TBC and SCC; and the alkaline-acid washing procedure of milking equipment with PIC and PC. The regression analysis explained the variation of bulk tank PC (- 0.47 log cfu/mL) due to the adoption of strip cup test (P = 0.036) and, by 0.366 log cfu/mL due to alkaline and acid washing of milking equipment (P = 0.036). Herringbone milking systems adopted on farms represented a change of - 0.11 log cfu/mL on the log SCC (P = 0.048). Findings may provide a guideline to prioritize efforts aimed at improving milk quality at the farm level in Brazil.

  6. ASSESSMENT OF THE EFFICIENCY OF DISINFECTION METHOD ...

    African Journals Online (AJOL)

    eobe

    ABSTRACT. The efficiencies of three disinfection methods namely boiling, water guard and pur purifier were assessed. ... Water is an indispensable resource for supporting life systems [2- ...... developing country context: improving decisions.

  7. Enhancement of ultraviolet water disinfection process

    African Journals Online (AJOL)

    grabi-1

    2013-05-15

    May 15, 2013 ... disinfected water distribution systems, including. Legionella .... soft agar, mixed, incubated at room temperature for 2 min and poured onto the ... The determination of a log increase methodology was employed to quantify the ...

  8. PROBIOTIC CLEANING PREPARATIONS VERSUS CHEMICAL DISINFECTANTS

    Directory of Open Access Journals (Sweden)

    W. Luepcke

    2017-12-01

    Full Text Available Probiotic detergents are increasingly used and are a real alternative for limiting the use of chemical cleaners, chemical disinfectants and antibiotics. They therefore have a great future because they contribute to animal health, to the hygienic production of food products of animal origin and to their harmlessness and to consumer health and environmental protection where they even have a beneficial effect on the microflora apart from chemical disinfectants that have a negative impact and destroy the beneficial microflora.

  9. Predictors of stethoscope disinfection among pediatric health care providers.

    Science.gov (United States)

    Muniz, Jeanette; Sethi, Rosh K V; Zaghi, Justin; Ziniel, Sonja I; Sandora, Thomas J

    2012-12-01

    Stethoscopes are contaminated with bacteria, but predictors of stethoscope disinfection frequency are unknown. We sought to describe health care provider stethoscope disinfection attitudes and practices and determine predictors of frequent disinfection. We used an anonymous online survey of nurses, nurse practitioners, and physicians at a pediatric hospital. We assessed frequency and methods of disinfection, perceptions of contamination, and barriers to disinfection. Multivariate logistic regression models were used to identify independent predictors of disinfecting after every use. One thousand four hundred one respondents completed the survey: 76% believed that infection transmission occurs via stethoscopes, but only 24% reported disinfecting after every use. In multivariate analyses, belief that infection transmission occurs via stethoscopes significantly increased the odds of disinfection after every use (odds ratio [OR], 2.06 [95% confidence interval (CI): 1.38-3.06]). The odds of disinfection after every use were significantly decreased in those who perceived the following barriers: lack of time (OR, 0.31 [95% CI: 0.18-0.54]), lack of access to disinfection material (OR, 0.41 [95% CI: 0.29-0.57]), or lack of visual reminders to disinfect (OR, 0.22 [95% CI: 0.14-0.34]). Only a minority of pediatric health care providers reported disinfecting their stethoscopes after every use. Increasing access to disinfection materials and visual reminders in health care facilities may improve stethoscope disinfection practices. Copyright © 2012 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.

  10. Loengud. Kontsert. Koorid. Teated

    Index Scriptorium Estoniae

    2006-01-01

    Loengust "Muusikaesseistika I" 19. sept. Lai t 34 aud 72. Kontsertidest: Tartu raekojas 22. sept. esineb hispaania ansambel Zarabanda, TÜ aulas 20. sept. esinevad "Meistrite akadeemia" sarjas Pille Lille Muusikute Toetusfondi laureaat Anna-Liisa Bezrodnõi viiulil ja Thea Nestor klaveril. TÜ Kammerkoor ja Tartu Akadeemiline Meeskoor võtavad vastu uusi liikmeid (info: www.ut.ee/TYKK ja www.tam.eu). Tartu Ülikooli rahvakunstiansambel ootab uusi tantsijaid (info: www.ut.ee)

  11. In vivo studies on lysosubtilin. 3. Efficacy for treatment of mastitis and superficial lesions of the udder and teats in cows.

    Science.gov (United States)

    Biziulevichius, G A; Lukauskas, K

    1998-01-01

    Lysosubtilin is a broad-spectrum preparation of lytic enzymes from Bacillus subtilis designed for veterinary medicine. This study demonstrates its efficacy for the treatment of reproductive system diseases (mastitis, superficial lesions of the udder and teats) in cows. Prior to determination of optimal therapeutic doses, samples taken from the milk and udder skin of sick animals were examined microbiologically. The examinations revealed a high incidence of polymicrobial infections (26.9 and 84.9% for mastitis and superficial udder lesions, respectively) caused by various mixtures of bacteria (both Gram-positive and Gram-negative) and fungi/yeasts. Dose determination studies involved 115 cows with clinical signs of mastitis. The optimal dose for mastitis treatment was found to be 3.5 x 10(6) U lysosubtilin dissolved in 100 mL of distilled water, which was then administered into the mammary gland via the teat canal once daily until recovery. Such a dose yielded statistically significant decreases (P < 0.05) both in the length of time before clinical recovery (2 d versus 4 and 4.5 d with either of the two antibiotic-based traditional drugs) and in the percentage of animals who suffered relapses within a 2-month period following treatment (5% versus 60%, with one of the two drugs). A field experiment involving 106 cows was designed to compare the efficacy of 1% lysosubtilin water-glycerin solution (1:9 v/v) and other traditional medications for the topical treatment of superficial lesions of the udder and teats as well as its potential for mastitis prevention. All drugs used yielded a 100% cure rate, but lysosubtilin application made it possible to achieve a statistically significant decrease (P < 0.05) in the duration of the recovery period (2.5 d versus 4.5 to 5.5 d) when compared with any of the four other drugs tested. Its efficacy for mastitis prevention was at least 3.4 times higher than the efficacy of the other medications used (statistically significant, P < 0

  12. Hospital disinfection: efficacy and safety issues.

    Science.gov (United States)

    Dettenkofer, Markus; Block, Colin

    2005-08-01

    To review recent publications relevant to hospital disinfection (and cleaning) including the reprocessing of medical instruments. The key question as to whether the use of disinfectants on environmental surfaces rather than cleaning with detergents only reduces nosocomial infection rates still awaits conclusive studies. New disinfectants, mainly peroxygen compounds, show good sporicidal properties and will probably replace more problematical substances such as chlorine-releasing agents. The safe reprocessing of medical devices requires a well-coordinated approach, starting with proper cleaning. New methods and substances show promising activity for preventing the transmission of prions. Different aspects of virus inactivation have been studied, and the transmissibility, e.g. of norovirus, shows the need for sound data on how different disinfectant classes perform. Biofilms or other forms of surface-adherent organisms pose an extraordinary challenge to decontamination. Although resistance to biocides is generally not judged to be as critical as antibiotic resistance, scientific data support the need for proper use, i.e. the avoidance of widespread application, especially in low concentrations and in consumer products. Chemical disinfection of heat-sensitive instruments and targeted disinfection of environmental surfaces are established components of hospital infection control. To avoid danger to staff, patients and the environment, prudent use as well as established safety precautions are required. New technologies and products should be evaluated with sound methods. As emerging resistant pathogens will challenge healthcare facilities in the future even more than at present, there is a need for well-designed studies addressing the role of disinfection in hospital infection control.

  13. Inactivation of an enterovirus by airborne disinfectants

    Science.gov (United States)

    2013-01-01

    Background The activity of airborne disinfectants on bacteria, fungi and spores has been reported. However, the issue of the virucidal effect of disinfectants spread by fogging has not been studied thoroughly. Methods A procedure has been developed to determine the virucidal activity of peracetic acid-based airborne disinfectants on a resistant non-enveloped virus poliovirus type 1. This virus was laid on a stainless carrier. The products were spread into the room by hot fogging at 55°C for 30 minutes at a concentration of 7.5 mL.m-3. Poliovirus inoculum, supplemented with 5%, heat inactivated non fat dry organic milk, were applied into the middle of the stainless steel disc and were dried under the air flow of a class II biological safety cabinet at room temperature. The Viral preparations were recovered by using flocked swabs and were titered on Vero cells using the classical Spearman-Kärber CPE reading method, the results were expressed as TCID50.ml-1. Results The infectious titer of dried poliovirus inocula was kept at 105 TCID50.mL-1 up to 150 minutes at room temperature. Dried inocula exposed to airborne peracetic acid containing disinfectants were recovered at 60 and 120 minutes post-exposition and suspended in culture medium again. The cytotoxicity of disinfectant containing medium was eliminated through gel filtration columns. A 4 log reduction of infectious titer of dried poliovirus inocula exposed to peracetic-based airborne disinfectant was obtained. Conclusion This study demonstrates that the virucidal activity of airborne disinfectants can be tested on dried poliovirus. PMID:23587047

  14. A practical evaluation of detergent and disinfectant solutions on ...

    African Journals Online (AJOL)

    Student01

    2012-01-06

    Jan 6, 2012 ... Nine sanitation chemical solutions: benzalkonium chloride, sodium hypochlorite, nitric ... cleaning and disinfection in reducing selected bacteria levels as required by ..... bacteria targeted during disinfection are attached to a.

  15. Basic Information about Chloramines and Drinking Water Disinfection

    Science.gov (United States)

    Chloramines are disinfectants used to treat drinking water. Chloramines are most commonly formed when ammonia is added to chlorine to treat drinking water. Chloramines provide longer-lasting disinfection as the water moves through pipes to consumers.

  16. Study and application of herbal disinfectants in China.

    Science.gov (United States)

    Chen, Zhao-Bin

    2004-12-01

    Disinfection means killing or removing pathogenic microorganisms in media to realize a harmless process. A disinfectant, which is also referred to as a disinfection medicine in relevant regulations, is the medicine used to kill microorganisms for the purpose of disinfection. The disinfectants prepared from plants (including traditional Chinese herbal medicines) and the extracts thereof are called herbal disinfectants. China has a long history of using herbal disinfectants. As early as in 533 A.D., the use of Cornel to sterilize well water was recorded in Necessary Techniques for Qi People by Jia Enxie of the Beiwei Dynasty. During the Dragon Boat Festival, people often use fumigants made of traditional Chinese herbal medicines like Chinese Atractylodes, Argy Wormwood Leaf and Red Arsenic Sulfide to smoke their houses, so as to ward off plagues and drive away evils. In fact this is now a kind of disinfection practice.

  17. [Experimental evaluation of the spraying disinfection efficiency on dental models].

    Science.gov (United States)

    Zhang, Yi; Fu, Yuan-fei; Xu, Kan

    2013-08-01

    To evaluate the disinfect effect after spraying a new kind of disinfectant on the dental plaster models. The germ-free plaster samples, which were smeared with bacteria compound including Staphylococcus aureus, Escherichia coli, Saccharomyces albicans, Streptococcus mutans and Actinomyces viscosus were sprayed with disinfectants (CaviCide) and glutaraldehyde individually. In one group(5 minutes later) and another group(15 minutes later), the colonies were counted for statistical analysis after sampling, inoculating, and culturing which were used for evaluation of disinfecting efficiency. ANOVA was performed using SPSS12.0 software package. All sample bacteria were eradicated after spraying disinfectants(CaviCide) within 5 minutes and effective bacteria control was retained after 15 minutes. There was significant difference between the disinfecting efficiency of CaviCide and glutaraldehyde. The effect of disinfection with spraying disinfectants (CaviCide) on dental models is quick and effective.

  18. Disinfection for small water supplies: a technical guide

    CSIR Research Space (South Africa)

    Solsona, F

    1990-01-01

    Full Text Available This guide will present some disinfection systems, which will be useful in supporting disinfection programmes. The description of the different systems will provide a guideline for the selection of equipment base on balancing the simplicity...

  19. OPTIMAL SCHEDULING OF BOOSTER DISINFECTION IN WATER DISTRIBUTION SYSTEMS

    Science.gov (United States)

    Booster disinfection is the addition of disinfectant at locations distributed throughout a water distribution system. Such a strategy can reduce the mass of disinfectant required to maintain a detectable residual at points of consumption in the distribution system, which may lea...

  20. Studies on Disinfection By-Products and Drinking Water

    Science.gov (United States)

    Rostad, Colleen E.

    2007-01-01

    Drinking water is disinfected with chemicals to remove pathogens, such as Giardia and Cryptosproridium, and prevent waterborne diseases such as cholera and typhoid. During disinfection, by-products are formed at trace concentrations. Because some of these by-products are suspected carcinogens, drinking water utilities must maintain the effectiveness of the disinfection process while minimizing the formation of by-products.

  1. Chemical aspects of peracetic acid based wastewater disinfection ...

    African Journals Online (AJOL)

    Peracetic acid (PAA) has been studied for wastewater disinfection applications for some 30 years and has been shown to be an effective disinfectant against many indicator microbes, including bacteria, viruses, and protozoa. One of the key advantages compared to, e.g., chlorine is the lack of harmful disinfection ...

  2. 40 CFR 141.172 - Disinfection profiling and benchmarking.

    Science.gov (United States)

    2010-07-01

    ... benchmarking. 141.172 Section 141.172 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Disinfection-Systems Serving 10,000 or More People § 141.172 Disinfection profiling and benchmarking. (a... sanitary surveys conducted by the State. (c) Disinfection benchmarking. (1) Any system required to develop...

  3. Effects of some antiseptics and disinfectants on Staphylococcus ...

    African Journals Online (AJOL)

    A total of 6 antiseptics and disinfectants at varying concentrations (20% - 100%) and contact time (10-60 minutes) were tested for the efficacy in the reduction of Staphylococcus aureus isolated from the hands of volunteers. Disinfectant 1 was the most effective disinfectant being bactericidal to S. aureus at 100% ...

  4. 9 CFR 91.41 - Cleaning and disinfecting of aircraft.

    Science.gov (United States)

    2010-01-01

    ... of this chapter. The time at which the cleaning and disinfection is performed must be approved by the inspector, who will give approval only if he or she determines that the cleaning and disinfection will be... time, the inspector shall determine whether further cleaning and disinfection are necessary. The...

  5. Technical considerations during disinfection by UV

    International Nuclear Information System (INIS)

    Ekhtiarzadeh, Z.; Sadeghpur, H.

    2002-01-01

    The use of new methods for treatment of water and wastewater in the country is one the rise and therefore the theoretical and practical knowledge of the industry's engineers should increase simultaneously. Ultraviolet is one of the new technologies used both for treatment of water as well as wastewater. The UV disinfection system consists of different components such as the lamp, ballast and the lamp fixtures. Each has a specification, which should be taken into account prior to design, order and purchase. The subject of price is also among the important considerations. The article presents figures cost comparison in various sections. It does not try to either approve or reject other disinfection systems such as chlorination, but the writer believes that any method should find its own practice and conditions of use, and the disinfection system designers should opt for the best system suited to their plans and avoid limiting themselves to a single one

  6. Intracellular mechanisms of solar water disinfection

    Science.gov (United States)

    Castro-Alférez, María; Polo-López, María Inmaculada; Fernández-Ibáñez, Pilar

    2016-12-01

    Solar water disinfection (SODIS) is a zero-cost intervention measure to disinfect drinking water in areas of poor access to improved water sources, used by more than 6 million people in the world. The bactericidal action of solar radiation in water has been widely proven, nevertheless the causes for this remain still unclear. Scientific literature points out that generation of reactive oxygen species (ROS) inside microorganisms promoted by solar light absorption is the main reason. For the first time, this work reports on the experimental measurement of accumulated intracellular ROS in E. coli during solar irradiation. For this experimental achievement, a modified protocol based on the fluorescent probe dichlorodihydrofluorescein diacetate (DCFH-DA), widely used for oxidative stress in eukaryotic cells, has been tested and validated for E. coli. Our results demonstrate that ROS and their accumulated oxidative damages at intracellular level are key in solar water disinfection.

  7. Activity and action screening of selected disinfectants

    Directory of Open Access Journals (Sweden)

    Kateřina Balharová

    2006-01-01

    Full Text Available This research work is aimed to monitoring of selected disinfectants´activity in operational conditions. Hereby there have been monitored two acidic disinfectants Despon K and Mikasan D, which have had-by their producer-stated different recommended concentration. These solutions were monitored in viewpoint of their activity at different temperature, time of circulation, pH and water hardness. In this work there were measured pH of solutions in unloaded medium to be compared with pH of solutions in loaded medium and this measuring was carried out regularly each week within a one month period. During this period there was also monitored total plate count (TPC, which was stated in the dairy, where samples were taken two-times monthly. It has been found, that the disinfectants Mikasan D and Mikal 94D are effective even by high water hardness.

  8. Photoreactivation Study of Wastewater Treatment Effluent Disinfected by UV-disinfection for Water Reuse

    International Nuclear Information System (INIS)

    Yoon, C.G.; Jung, K.W.; Ham, J.H.; Jeon, J.H.

    2003-01-01

    Photoreactivation of microorganism following UV-disinfection is one of the research topics of interest in assessing the UV-disinfection performance. Apparent photoreactivation was examined under fluorescent lamp and solar radiation as well as in darkness. Total coliform, fecal coliform, and Escherichia coli were used as indicator microorganisms, and their concentration of 10~30 MPN/100mL increased to the level of 100 MPN/100mL after 24 hours, which implied that part of damaged microorganisms by UV-disinfection might be repairable with time

  9. Ultraviolet air disinfection for protection against influenza

    International Nuclear Information System (INIS)

    Riley, R.L.

    1977-01-01

    Three converging lines of evidence support the belief that it may be possible, under appropriate circumstances, to interrupt the airborne transmission of influenza by ultraviolet (UV) air disinfection. These lines of evidence are: (a) that influenza is airborne; (b) that UV irradiation of the upper air of a room can provide safe and effective disinfection of air in the lower part of the room; and (c) that epidemic spread of airborne viral infections in humans can be prevented if the population under consideration remains in the UV-protected environment

  10. Drinking water contamination and it's disinfection

    International Nuclear Information System (INIS)

    Shah, P.M.J.

    2005-01-01

    High quality water is necessary for the survival of human life. In this paper, an effort has been made to highlight the various causes of water contamination. Some of the most common impurities present in water are pathogenic microorganisms along with organize and in organize pollutants. Different treatment methods are adopted to ensure the potability of water. They include physical, chemical and ultra viable treatment along with solar disinfection etc. The adoption of a particular disinfection strategy depends on the level of treatment required and the resources available to carry out such a treatment. (author)

  11. Sensitivity to disinfection of bacterial indicator organisms for monitoring the Salmonella Enteritidis status of layer farms after cleaning and disinfection.

    Science.gov (United States)

    Dewaele, I; Ducatelle, R; Herman, L; Heyndrickx, M; De Reu, K

    2011-06-01

    The present study evaluated Escherichia coli, Enterococcus faecalis, and Enterococcus hirae as potential indicator organisms for the possible Salmonella Enteritidis (SE) presence in layer farms after cleaning and disinfection by comparing their susceptibility to disinfection. A quantitative suspension disinfection test according to European Standard EN1656 was performed using disinfection products CID20 and Virocid (both from CID Lines, Ieper, Belgium). In a preliminary test, the sensitivity to both disinfection products was compared between ATCC strains of SE, E. coli, En. faecalis, and En. hirae. The sensitivity of SE to disinfection was most comparable to that of E. coli. A second disinfection test compared the elimination of E. coli to SE ATCC strains as well as field strains. Results showed no significant effect regarding the strain (P > 0.05 for CID20 and Virocid), meaning that no difference was detected in sensitivity toward disinfection. When comparing the sensitivity in general at species level for all concentrations of disinfectant used, no significant difference was found between E. coli and SE in sensitivity to Virocid (P > 0.05). In conclusion, because of its similar response to disinfection in a suspension disinfection test, E. coli could be used as an indicator for possible Salmonella presence after cleaning and disinfection.

  12. A bacteriological study of hospital beds before and after disinfection with phenolic disinfectant

    OpenAIRE

    Denise de Andrade; Emília L. S. Angerami; Carlos Roberto Padovani

    2000-01-01

    In hospitals, one of the ways to control microbial contamination is by disinfecting the furniture used by patients. This study's main objective was to evaluate the microbiological condition of hospital mattresses before and after such disinfection, in order to identify bacteria that are epidemiologically important in nosocomial infection, such as Staphylococcus aureus and Pseudomonas aeruginosa. RODAC plates with two different culture media were used to collect specimens. Patient beds were se...

  13. A bacteriological study of hospital beds before and after disinfection with phenolic disinfectant

    Directory of Open Access Journals (Sweden)

    Andrade Denise de

    2000-01-01

    Full Text Available In hospitals, one of the ways to control microbial contamination is by disinfecting the furniture used by patients. This study's main objective was to evaluate the microbiological condition of hospital mattresses before and after such disinfection, in order to identify bacteria that are epidemiologically important in nosocomial infection, such as Staphylococcus aureus and Pseudomonas aeruginosa. RODAC plates with two different culture media were used to collect specimens. Patient beds were selected according to previously established criteria, and surface areas on the mattresses were chosen at random. From the total of 1 040 plate cultures from 52 mattresses, positive results were obtained from 500 of them (48.1%, 263 before disinfection and 237 after disinfection. Considering the selectivity of the culture media, the positivity rate was high. There were high prevalences of S. aureus both before and after mattress disinfection. The study results suggest that the usual disinfection procedures, instead of diminishing the number of microbes, merely displace them from one part of the mattress to another, and the number of microorganisms remains the same.

  14. A bacteriological study of hospital beds before and after disinfection with phenolic disinfectant

    Directory of Open Access Journals (Sweden)

    Denise de Andrade

    2000-03-01

    Full Text Available In hospitals, one of the ways to control microbial contamination is by disinfecting the furniture used by patients. This study's main objective was to evaluate the microbiological condition of hospital mattresses before and after such disinfection, in order to identify bacteria that are epidemiologically important in nosocomial infection, such as Staphylococcus aureus and Pseudomonas aeruginosa. RODAC plates with two different culture media were used to collect specimens. Patient beds were selected according to previously established criteria, and surface areas on the mattresses were chosen at random. From the total of 1 040 plate cultures from 52 mattresses, positive results were obtained from 500 of them (48.1%, 263 before disinfection and 237 after disinfection. Considering the selectivity of the culture media, the positivity rate was high. There were high prevalences of S. aureus both before and after mattress disinfection. The study results suggest that the usual disinfection procedures, instead of diminishing the number of microbes, merely displace them from one part of the mattress to another, and the number of microorganisms remains the same.

  15. Carbon nanoparticles for solar disinfection of water.

    Science.gov (United States)

    Maddigpu, Pratap Reddy; Sawant, Bhairavi; Wanjari, Snehal; Goel, M D; Vione, Davide; Dhodapkar, Rita S; Rayalu, S

    2018-02-05

    The present manuscript deals with the application of carbon nano particles (CNP) and chitosan (CHIT) in the form of CHIT-CNP composite for the disinfection of water. The CHIT-CNP composite was prepared by the solution casting method and characterized by TEM, XRD and elemental analysis. In the present investigation we study the disinfection efficiency towards E. coli bacteria of both CNP and CHIT-CNP, under sunlight (SODIS) in identical experimental conditions. Both CNP and CHIT-CNP enhanced disinfection as compared to SODIS alone, and comparable performance was achieved when the same dose of CNP in the two materials was applied. However, the CHIT-CNP composite is in the form of a fabric and it is easier to use and handle as compared to the CNP powder, especially in rural and resource-constrained areas. Moreover the SODIS-CHIT-CNP setup, when used in a compound parabolic collector (CPC) reactor showed high bactericidal efficiency compared to SODIS alone, which is promising for practical applications. The disinfection potential of the CNP powder was compared with that of the well-known material TiO 2 Degussa P25 (DP 25 ): DP 25 gave 6-log kill of bacteria in 180min, whereas CNP produced 6-log kill in 150min. Copyright © 2017. Published by Elsevier B.V.

  16. essential oil as hatching egg disinfectant

    African Journals Online (AJOL)

    STORAGESEVER

    2010-04-26

    Apr 26, 2010 ... disinfectant for hatching egg obtained from broiler breeder flock. Oregano essential ... contamination rate, hatchability of fertile egg, body weight at 21 and 42 days, body weight gain and total feed ... successful healthy hatchlings. Several ...... Insecticidal properties of essential plant oils against the mosquito.

  17. STERILIZATION AND DISINFECTION IN A PRIVATE CLINIC

    African Journals Online (AJOL)

    Oral examination is done with a mirror and probe. The mirror is then washed under the tap water and disinfected in 'V3 sterilizing' fluid concentrate. The probe is placed in a tray with ... Protective glasses are worn additionally to the gloves and facemask, when cavity preparation. is being performed. The handpiece is wiped.

  18. USE OF FENTON'S REAGENT AS A DISINFECTANT

    Science.gov (United States)

    Combined sewage samples obtained from a wastewater treatment facility were disinfected by the Fenton's Reagent of several different compositions. The pre-settled samples contained both suspended solids (SS) and dissolved organic carbon (DOC) at concentrations of 28 and 290 mg/L,...

  19. Disinfection of dental impressions - compliance to accepted standards.

    Science.gov (United States)

    Almortadi, N; Chadwick, R G

    2010-12-18

    The responsibility of ensuring impressions have been cleaned and disinfected before dispatch to the dental laboratory lies solely with the dentist. Uncertainty of impression disinfection risks both the health of the receiving dental technician and potential repeat disinfection of an already disinfected impression with detrimental consequences for its dimensions. To ascertain, from the perspectives of dentists and dental technicians, current impression decontamination and disinfection practices with, in the case of the technicians, an estimate of the relative prevalence of contaminated voids within apparently disinfected impressions. Anonymous postal questionnaire. Dentist (n = 200) and dental technician (n = 200) potential participants, selected at random from the registers held by the General Dental Council, were invited to complete an anonymous postal questionnaire that sought to establish current practices and perceived effectiveness of impression disinfection. Questionnaire return rates of 42.1% and 31.2% were recorded for dentists and dental technicians respectively. A wide range of solutions, at different dilutions of the same product, was used by the dentists to disinfect dental impressions. 37.2% rinsed the impressions with water, and 2.6% always brushed debris away, before disinfection. 24.7% of dentists did not inform the laboratory of disinfection. Irrespective of the disinfection status of the received impressions, 50% of the responding dental technicians disinfected all impressions. 95% of them had received blood-contaminated impressions. 15% had encountered blood-filled voids upon trimming back the peripheries of impressions. 64.7% were confident that the impressions received by them had been disinfected by the dentists. Compliance with good practice is less than ideal and education in impression disinfection for both dentists and dental technicians is required to address this.

  20. A comparison of the effect of short-acting and long-acting cloxacillin-based dry-cow therapy on somatic cell counts after calving in cows also given internal teat sealants.

    Science.gov (United States)

    Whitfield, L K; Laven, R A

    2018-01-01

    To compare, in cows treated with an internal teat sealant, the effect of short-acting and long-acting cloxacillin-based dry-cow therapy on somatic cell counts (SCC) after calving. Cows from a spring-calving, pasture-based dairy farm in the Manawatu-Whanganui region of New Zealand were randomly allocated to receive either a short-acting cloxacillin and ampicillin dry-cow therapy and internal teat sealant (n=291) or a long-acting cloxacillin and ampicillin dry-cow therapy and internal teat sealant (n=288) at the end of lactation. Cows were managed on-farm with routine husbandry procedures through the dry period and following calving. A multivariable logistic regression model was used to determine the association between length of action of dry-cow therapy and the proportion of cows with a SCC >150,000 cells/mL at the first herd test after calving. Age of cow, mean SCC for the preceding season and interval from calving to the first post-calving herd test were all associated with the proportion of cows with an individual SCC >150,000 cells/mL at the first herd test (pcow therapy was not associated with decreased odds of cows having a SCC >150,000 cells/mL at the first herd test compared with treatment with long-acting dry-cow therapy (OR=0.724; 95% CI=0.40-1.30). In this herd, which routinely used internal teat sealants, the use of short-acting cloxacillin-based dry-cow therapy did not result in an increased proportion of cows with elevated SSC post-calving. This was a single farm, single year study but indicates that in this herd, changing from a long-acting to a short-acting antimicrobial may have no impact on the prevalence of subclinical mastitis.

  1. Comparison of cephalonium alone and in combination with an internal teat sealant for dry cow therapy in seasonally calving dairy cows.

    Science.gov (United States)

    Bates, A J; Chambers, G; Laven, R A

    2016-03-01

    To assess the effect of combining an internal teat sealant (ITS) and a long-acting cephalonium-based dry cow therapy (DCT) on the prevalence of cows with a somatic cell count (SCC) >150,000 cells/mL 60-80 days after calving, and the incidence of clinical mastitis diagnosed by farm staff in the first 100 days after calving. Cows from a spring-calving, pasture-based, dairy farm in the South Canterbury region of New Zealand were randomly allocated to receive cephalonium DCT (n=289) or cephalonium and internal teat sealant (n=304) at the end of lactation. Cows were inspected twice daily by farm staff during the dry period and following calving for signs of mastitis. Individual SCC were determined from herd tests conducted in the previous lactation and following calving. Logistic regression models were used to determine relationships with the prevalence of cows with a SCC >150,000 cells/mL after calving, and survival analysis was used to model time to the first case of clinical mastitis following calving at the cow and quarter level. The OR for a cow with a SCC >150,000 cells/mL after calving, including age and individual SCC in the preceding lactation in the model, was 0.53 (95% CI=0.32-0.89) for cows treated with combination therapy compared to cows receiving cephalonium (p=0.017). At the cow level, including age and preceding SCC in the model, the hazard ratio for diagnosis of clinical mastitis by farm staff in the first 100 days of lactation was 0.60 (95% CI=0.39-0.98) for cows treated with combination therapy compared to cows receiving cephalonium (p=0.04). At the quarter level, the hazard ratio for diagnosis of clinical mastitis, with age included in the model, was 0.41 (95% CI=0.23-0.74) for the combination therapy compared to cephalonium alone (pmastitis diagnosed by farm staff in the 100 days after calving, and the prevalence of cows with a SCC >150,000 cells/mL 60-80 days after calving. This study adds to the evidence that the prevention of intra mammary

  2. Bovine teat microbiome analysis revealed reduced alpha diversity and significant changes in taxonomic profiles in quarters with a history of mastitis

    Directory of Open Access Journals (Sweden)

    Helene eFalentin

    2016-04-01

    Full Text Available Mastitis is a mammary gland inflammatory disease often due to bacterial infections. Like many other infections, it used to be considered as a host-pathogen interaction driven by host and bacterial determinants. Until now, the involvement of the bovine mammary gland microbiota in the host-pathogen interaction has been poorly investigated, and mainly during the infectious episode. In this study, the bovine teat microbiome was investigated in 31 quarters corresponding to 27 animals, which were all free of inflammation at sampling time but which had different histories regarding mastitis: from no episode of mastitis on all the previous lactations (Healthy quarter, Hq to one or several clinical mastitis events (Mastitic quarter, Mq. Several quarters whose status was unclear (possible history of subclinical mastitis were classified as NDq. Total bacterial DNA was extracted from foremilk samples and swab samples of the teat canal. Taxonomic profiles were determined by pyrosequencing on 16s amplicons of the V3-4 region. Hq quarters showed a higher diversity compared to Mq ones (Shannon index: ~8 and 6, respectively. Clustering of the quarters based on their bacterial composition made it possible to separate Mq and Hq quarters into two separate clusters (C1 and C2, respectively. Discriminant analysis of taxonomic profiles between these clusters revealed several differences and allowed the identification of taxonomic markers in relation to mastitis history. C2 quarters were associated with a higher proportion of the Clostridia class (including genera such as Ruminococcus, Oscillospira, Roseburia, Dorea, etc., the Bacteroidetes phylum (Prevotella, Bacteroides, Paludibacter, etc., and the Bifidobacteriales order (Bifidobacterium, whereas C1 quarters showed a higher proportion of the Bacilli class (Staphylococcus and Chlamydiia class. These results indicate that microbiota is altered in udders which have already developed mastitis, even far from the

  3. Peracetic Acid as a Green Disinfectant for Combined Sewer ...

    Science.gov (United States)

    This cooperative research and development agreement between U.S. EPA, Solvay, MSDGC, and CB&I is evaluating the potential of PAA for disinfection of Muddy Creek CSO wastewater and comparing that with sodium hypochlorite disinfection. This presentation will document the effectiveness of sodium hypochlorite and PAA for the inactivation of E. coli in CSO wastewater using laboratory bench-scale jar tests and Muddy Creek field site studies based on the following items:•Storage, shelf life, and application of the disinfectants.•Effectiveness of the disinfectants in the inactivation of E. coli.•Formation of harmful byproducts by the disinfectants.•Operation and maintenance costs, including the cost of the disinfectant, its storage, application, and neutralizing agent for the disinfectant to maintain the Ohio EPA guideline for residual disinfectant at the discharge point. Like many cities in the USA, Cincinnati, Ohio is attempting to find the best way to meet state and federal requirements concerning combined sewer overflow (CSO) wastewater. The Muddy Creek CSO treatment facility was constructed to provide treatment for CSO Numbers 198 and 216 from the Westwood Trunk sewer. The Metropolitan Sewer District of Greater Cincinnati (MSDGC) is currently using sodium hypochlorite for disinfection in this treatment facility. Because of degradation of hypochlorite during storage and the formation of chlorinated disinfection byproducts (DBPs), MSDGC is evaluating alternat

  4. Peracetic acid for secondary effluent disinfection: a comprehensive performance assessment.

    Science.gov (United States)

    Antonelli, M; Turolla, A; Mezzanotte, V; Nurizzo, C

    2013-01-01

    The paper is a review of previous research on secondary effluent disinfection by peracetic acid (PAA) integrated with new data about the effect of a preliminary flash-mixing step. The process was studied at bench and pilot scale to assess its performance for discharge in surface water and agricultural reuse (target microorganisms: Escherichia coli and faecal coliform bacteria). The purposes of the research were: (1) determining PAA decay and disinfection kinetics as a function of operating parameters, (2) evaluating PAA suitability as a disinfectant, (3) assessing long-term disinfection efficiency, (4) investigating disinfected effluent biological toxicity on some aquatic indicator organisms (Vibrio fischeri, Daphnia magna and Selenastrum capricornutum), (5) comparing PAA with conventional disinfectants (sodium hypochlorite, UV irradiation). PAA disinfection was capable of complying with Italian regulations on reuse (10 CFU/100 mL for E. coli) and was competitive with benchmarks. No regrowth phenomena were observed, as long as needed for agricultural reuse (29 h after disinfection), even at negligible concentrations of residual disinfectant. The toxic effect of PAA on the aquatic environment was due to the residual disinfectant in the water, rather than to chemical modification of the effluent.

  5. [Control of disinfection in buildings used for poultry raising].

    Science.gov (United States)

    Maris, P

    1989-01-01

    During a 2-year survey in turkey breeding farms, it was possible to compare six disinfection procedures by monitoring 14 first disinfections following the breeding house cleaning and 14 second disinfections prior to animal return. By swabbing all the germs from asbestos concrete surfaces, we noted that in the case of first disinfection the chloramine T-based product was more effective than phenol or quaternary ammonium-aldehyde-based products. For the second disinfection, it was demonstrated that a minimal dose of 15 kg of formaldehyde was necessary for disinfection to be satisfactory; 12 to 15 kg paraformaldehyde was as effective as 40 to 60 liters of 30-35% formol for buildings, the ground surface of which covered between 1,000 and 1,300 m2.

  6. Application and study of conjunctival sac disinfectants in ophthalmic surgeries

    Directory of Open Access Journals (Sweden)

    Yan-Fei Luo

    2016-01-01

    Full Text Available Postoperative endophthalmitis is the most serious complications of ophthalmic surgeries. Conjunctival sac disinfection is currently recognized as an effectively important way to reduce the risk of endophthalmitis. At present, there are some disinfectants has been used in clinic or in the researches:mercury agent, gentamicin, povidone iodine and acid electrolytic water. All kinds of disinfectants play the role of disinfection by different ways. Povidone iodine is the most widely used conjunctival sac disinfectant. Mercurial and gentamicin have been rarely used because they pollute the environment, are easy to cause drug resistant bacteria, localized side reactions and so on. The acid electrolyte water is not used in clinic at present. With the popularization and development of the ophthalmic surgeries, the ophthalmologists have become more and more concerned about the postoperative eye comfort, the research and application of conjunctival sac disinfectant in the future will continue to be updated and developed.

  7. Mode of action and in vitro susceptibility of mastitis pathogens to macedocin ST91KM and preparation of a teat seal containing the bacteriocin

    Directory of Open Access Journals (Sweden)

    Renee Pieterse

    2010-03-01

    Full Text Available Mastitis is considered to be the most economically costly disease affecting the dairy industry. Regular dosage of animals with antibiotics, including use of prophylactic concentrations, may select for resistant strains. The purpose of this study was to determine the mode of action of a new bacteriocin (macedocin ST91KM, to evaluate the antimicrobial resistance of mastitis pathogens to antibiotics commonly used in treatment remedies, and to introduce the possible use of an alternative antimicrobial agent. The bacteriocin macedocin ST91KM, produced by Streptococcus gallolyticus subsp. macedonicus ST91KM, is bactericidal to Streptococcus agalactiae, Streptococcus dysgalactiae, Streptococcus uberis and Staphylococcus aureus associated with mastitis infections, including strains resistant to methicillin and oxacillin. Sensitive cells were deformed and secreted nucleotides, K+ and β-galactosidase when exposed to macedocin ST91KM. Adsorption of the peptide to target cells decreased in the presence of solvents, suggesting that receptors on the cell surfaces have lipid moieties. No adsorption was recorded in the presence of MgCl2, KI and Na2CO3, suggesting that ionic strength plays an important role. A teat seal preparation containing macedocin ST91KM effectively released the peptide and inhibited the growth of S. agalactiae. Macedocin ST91KM could form the basis for alternative dry cow therapy to prevent mastitis infections in dairy cows as it is effective against pathogens that display resistance to conventional antibiotic therapy.

  8. Design and characterisation of a polyethylene oxide matrix with the potential use as a teat insert for prevention/treatment of bovine mastitis.

    Science.gov (United States)

    Bhattarai, Sushila; Alany, Raid G; Bunt, Craig R; Abdelkader, Hamdy; Rathbone, Michael J

    2015-01-01

    This manuscript reports (for the first time) on antibiotic-free polymeric inserts for the prevention and/or treatment of bovine mastitis. Polyethylene oxide (PEO)-based inserts were prepared using different concentrations of various hydrophilic polymers and water-soluble and water-insoluble drug-release-modifying excipients. A simple and scalable melt-extrusion method was employed to prepare the inserts. The prepared inserts were characterised for their dimension, rheological and mechanical properties. The in vitro release of a model bacteriostatic drug (salicylic acid) from the prepared inserts was studied to demonstrate the effectiveness and reproducibility of the melt-extrusion manufacturing method. Further, the in vitro stability of the inserts was evaluated using gel permeation chromatography (GPC) to monitor any change in molecular weight under real-time and accelerated storage conditions. The investigated inserts were stable at accelerated storage conditions over a period of 6 months. PEO inserts have the potential to serve a dual purpose, act as a physical barrier against pathogens invading the teat canal of cows and possibly control the release of a drug.

  9. Is free halogen necessary for disinfection?

    Science.gov (United States)

    Williams, D E; Elder, E D; Worley, S D

    1988-10-01

    The principle of Le Chatelier was used in demonstrating that 3-chloro-4,4-dimethyl-2-oxazolidinone (compound 1) itself kills Staphylococcus aureus rather than the very small amount of free chlorine in hydrolysis equilibrium with compound 1. On the other hand, when the N-bromo analog of compound 1 (compound 1B) was used as the disinfectant, the mixture of combined compound 1B and free bromine formed in the hydrolysis equilibrium provided disinfection. When the hydrolysis equilibrium for 1B was suppressed to the level at which a negligible amount of free bromine remained in solution, combined compound 1B was much more efficacious than combined compound 1 at killing S. aureus.

  10. Ultraviolet light - nature's own disinfection process

    Energy Technology Data Exchange (ETDEWEB)

    Munkeberg, T [Thorolf Gregersen a/s, Oslo (Norway)

    1978-05-18

    Ultraviolet radiation from the sun is the means by which natural pollution products, as well as much of the smaller amount of pollution products produced by man, are converted and returned to the cycle of nature. Artificial ultraviolet radiation offers an optimum method for the disinfection of drinking water and can be used in the long term without undesireable effects on man or the enviromment. There is no evidence that ultraviolet irradiation leads to radiation resistant mutations of bacteria. The geometrical arrangement of ultraviolet disinfection units is described and the capacities of typical units is mentioned as being 600-800 m/sup 3/ /hr, though there is no reason why this should not be increased.

  11. Ultraviolet light - nature's own disinfection process

    International Nuclear Information System (INIS)

    Munkeberg, T.

    1978-01-01

    Ultraviolet radiation from the sun is the means by which natural pollution products, as well as much of the smaller amount of pollution products produced by man, are converted and returned to the cycle of nature. Artificial ultraviolet radiation offers an optimum method for the disinfection of drinking water and can be used in the long term without undesireable effects on man or the enviromment. There is no evidence that ultraviolet irradiation leads to radiation resistant mutations of bacteria. The geometrical arrangement of ultraviolet disinfection units is described and the capacities of typical units is mentioned as being 600-800 m 3 /hr, though there is no reason why this should not be increased. (JIW)

  12. Assessment of photoreactivation following ultraviolet light disinfection

    International Nuclear Information System (INIS)

    Kashimada, K.; Kamiko, N.; Yamamoto, K.; Ohgaki, S.

    1996-01-01

    Photoreactivation of microorganisms following UV disinfection is one of the research topics of interest in assessing the performance of UV disinfection, because there is little consensus on how the visible light intensity relates to the photoreactivation rate and the maximum survival in wastewater treatment processes. Apparent photoreactivation by a fluorescent lamp was observed in case of indicator bacteria (heterotrophic bacteria, coliform bacteria, fecal coliforms) in raw sewage, but not E. coli B and E. coli K12 A/λ(F+). Inactivation of fecal coliform was observed simultaneously during photoreactivation process by sunlight. Dose rate at 360 nm wave length as visible light intensity showed that it was a useful indicator for assessing the photoreactivation rate and the maximum survival when photoreactivation took place by both fluorescent lamp and sunlight. The model for photoreactivation was developed. The photoreactivation rate increased with increasing visible light intensity at 360 nm. However, the maximum survival value may not be affected by visible light intensity. (author)

  13. UV DISINFECTION GUIDANCE MANUAL FOR THE ...

    Science.gov (United States)

    Provides technical information on selection, design and operation of UV systems; provides regulatory agencies with guidance and the necessary tools to assess UV systems at the design, start-up, and routine operation phase; provides manufacturers with the testing and performance standards for UV components and systems for treating drinking water. Provide guidance to water systems, regulators and manufacturers on UV disinfection of drinking water.

  14. Role of disinfection in the Infection Prevention Multibarrier System

    OpenAIRE

    Kramer, Axel

    2007-01-01

    The role of disinfection in infection prevention has been analyzed over the past 50 years both in the form of benefit-risk evaluations as well as in an epidemiological sense. This has served as the basis for not only national and international guidelines and recommendations, but has also created the legal and normative framework for regulation of infection control (and hence of disinfection) in numerous and acts and ordinances. Likewise, today the efficacy of disinfection measures, user safet...

  15. Efficacy of a variety of disinfectants against Listeria spp.

    OpenAIRE

    Best, M; Kennedy, M E; Coates, F

    1990-01-01

    The efficacy of 14 disinfectants against Listeria innocua and two strains of Listeria monocytogenes in the presence of organic matter was studied. Quantitative efficacy tests were used. Many of the disinfectants tested were not as effective on Listeria spp. when the test organisms were dried onto the surface of steel disks (carrier tests) as they were when the organisms were placed in suspension (suspension test). The presence of whole serum and milk (2% fat) further reduced the disinfectant ...

  16. Bacterial Spores Survive Treatment with Commercial Sterilants and Disinfectants

    OpenAIRE

    Sagripanti, Jose-Luis; Bonifacino, Aylin

    1999-01-01

    This study compared the activity of commercial liquid sterilants and disinfectants on Bacillus subtilis spores deposited on three types of devices made of noncorrodible, corrodible, or polymeric material. Products like Renalin, Exspor, Wavicide-01, Cidexplus, and cupric ascorbate were tested under conditions specified for liquid sterilization. These products, at the shorter times indicated for disinfection, and popular disinfectants, like Clorox, Cavicide, and Lysol were also studied. Data ob...

  17. Development of the electrical discharge method for water disinfection

    International Nuclear Information System (INIS)

    Vojtenko, L.M.; Kononov, O.V.; Starchik, P.D.; Samojlenko, L.S.; Stavs'ka, S.S.

    1995-01-01

    Studies of processes of bacterially polluted water disinfection by the method of pulse electrical discharge in water are presented. The studies was performed to improve the disinfection technology. Main attention was concentrated to clear up effect of discharge instability on the disinfection. An influence of the shape and sizes of electrodes on repeatability of discharges was also investigated. It was found that salts solved in water greatly influence ultraviolet radiation absorption coefficients

  18. Spiral-shaped reactor for water disinfection

    KAUST Repository

    Soukane, Sofiane

    2016-04-20

    Chlorine-based processes are still widely used for water disinfection. The disinfection process for municipal water consumption is usually carried out in large tanks, specifically designed to verify several hydraulic and disinfection criteria. The hydrodynamic behavior of contact tanks of different shapes, each with an approximate total volume of 50,000 m3, was analyzed by solving turbulent momentum transport equations with a computational fluid dynamics code, namely ANSYS fluent. Numerical experiments of a tracer pulse were performed for each design to generate flow through curves and investigate species residence time distribution for different inlet flow rates, ranging from 3 to 12 m3 s−1. A new nature-inspired Conch tank design whose shape follows an Archimedean spiral was then developed. The spiral design is shown to strongly outperform the other tanks’ designs for all the selected plug flow criteria with an enhancement in efficiency, less short circuiting, and an order of magnitude improvement in mixing and dispersion. Moreover, following the intensification philosophy, after 50% reduction in its size, the new design retains its properties and still gives far better results than the classical shapes.

  19. Biological Treatment of Water Disinfection Byproducts using ...

    Science.gov (United States)

    Major disinfection by-products (DBPs) from the chlorination process of drinking water include trihalomethanes (THMs) and haloacetic acides (HAA5). THMs mainly consist of chloroform, and other harsh chemicals. Prolonged consumptions of drinking water containing high levels of THMs has been linked with diseases of the liver, kidneys, bladder, or central nervous system and may increase likelihood of cancer. A risk also exists for THMs exposure via inhalation while showering, bathing or washing clothes and dishes. Due to these risks, the U.S. EPA regulate THMs content in drinking water. This research investigates biological degradation of THM using chloroform as a model compound. The study aims to decrease possible risks of THMs through filtration. Throughout this year’s presentations, there is a common theme of health and safety concerns. UC researchers are working hard to clean water ways of naturally occurring contaminates as well as man-made toxins found in our waterways. The significance of these presentations translates into the promise of safer environments, and more importantly saved lives, as UC’s faculty continues to produce real-world solutions to problems threatening the world around us. A biotech process has been developed and demonstrated that effectively remove and treat volatile disinfection by-products from drinking water. The process strips low concentration disinfection by-products, such as trihalomethanes, that are formed during the chlori

  20. Evaluation of toothbrush disinfection via different methods

    Directory of Open Access Journals (Sweden)

    Adil BASMAN

    2016-01-01

    Full Text Available The aim of this study was to compare the efficacy of using a dishwasher or different chemical agents, including 0.12% chlorhexidine gluconate, 2% sodium hypochlorite (NaOCl, a mouthrinse containing essential oils and alcohol, and 50% white vinegar, for toothbrush disinfection. Sixty volunteers were divided into five experimental groups and one control group (n = 10. Participants brushed their teeth using toothbrushes with standard bristles, and they disinfected the toothbrushes according to instructed methods. Bacterial contamination of the toothbrushes was compared between the experimental groups and the control group. Data were analyzed by Kruskal–Wallis and Duncan's multiple range tests, with 95% confidence intervals for multiple comparisons. Bacterial contamination of toothbrushes from individuals in the experimental groups differed from those in the control group (p < 0.05. The most effective method for elimination of all tested bacterial species was 50% white vinegar, followed in order by 2% NaOCl, mouthrinse containing essential oils and alcohol, 0.12% chlorhexidine gluconate, dishwasher use, and tap water (control. The results of this study show that the most effective method for disinfecting toothbrushes was submersion in 50% white vinegar, which is cost-effective, easy to access, and appropriate for household use.

  1. Bacterial spores survive treatment with commercial sterilants and disinfectants.

    Science.gov (United States)

    Sagripanti, J L; Bonifacino, A

    1999-09-01

    This study compared the activity of commercial liquid sterilants and disinfectants on Bacillus subtilis spores deposited on three types of devices made of noncorrodible, corrodible, or polymeric material. Products like Renalin, Exspor, Wavicide-01, Cidexplus, and cupric ascorbate were tested under conditions specified for liquid sterilization. These products, at the shorter times indicated for disinfection, and popular disinfectants, like Clorox, Cavicide, and Lysol were also studied. Data obtained with a sensitive and quantitative test suggest that commercial liquid sterilants and disinfectants are less effective on contaminated surfaces than generally acknowledged.

  2. Less skin irritation from alcohol-based disinfectant than from detergent used for hand disinfection

    DEFF Research Database (Denmark)

    Pedersen, L K; Held, E; Johansen, J D

    2005-01-01

    and forearms of 17 healthy volunteers. A control area was included. After 4 weeks an SLS patch was applied to each area. Irritant reactions were quantified with a visual score recording and measurements of transepidermal water loss (TEWL) and skin colour were performed on days 1, 5, 11, 38 and 40. RESULTS...... was found on the disinfectant-treated area compared with the control area and detergent area, and a similar trend was found for TEWL, although it was not statistically significant. CONCLUSION: Alcohol-based disinfectant caused less visible skin irritation and less skin barrier disruption than the use...

  3. MUTAGENICITY AND DISINFECTION BY-PRODUCTS IN SURFACE DRINKING WATER DISINFECTED WITH PERACETIC ACID

    Science.gov (United States)

    The aims of this research were to study the influence of peracetic acid (PAA) on the formation of mutagens in surface waters used for human consumption and to assess its potential application for the disinfection of drinking water. The results obtained using PAA were compared to ...

  4. 21 CFR 880.6890 - General purpose disinfectants.

    Science.gov (United States)

    2010-04-01

    ... (CONTINUED) MEDICAL DEVICES GENERAL HOSPITAL AND PERSONAL USE DEVICES General Hospital and Personal Use... disinfectant is a germicide intended to process noncritical medical devices and equipment surfaces. A general... prior to terminal sterilization or high level disinfection. Noncritical medical devices make only...

  5. [Scanning electron microscope study of chemically disinfected endodontic files].

    Science.gov (United States)

    Navarro, G; Mateos, M; Navarro, J L; Canalda, C

    1991-01-01

    Forty stainless steel endodontic files were observed at scanning electron microscopy after being subjected to ten disinfection cycles of 10 minutes each one, immersed in different chemical disinfectants. Corrosion was not observed on the surface of the files in circumstances that this study was made.

  6. Ozone reactions with indoor materials during building disinfection

    DEFF Research Database (Denmark)

    Poppendieck, D.; Hubbard, H.; Ward, M.

    2007-01-01

    , and particularly after several hours of disinfection, surface reaction resistance dominated the overall resistance to ozone deposition for nearly all materials. Total building disinfection by-products (all carbonyls) were quantified per unit area of each material for the experimental period. Paper, office...... partition, and medium density fiberboard each released greater than 38 mg m(-2) of by-products....

  7. The antimicrobial activities of some commonly used disinfectants on ...

    African Journals Online (AJOL)

    The disinfectants; SavlonR, JikR, Methylated spirit and kerosene were observed for their inhibitory activities on Bacillus subtilis, Pseudomonas aeruginosa and Candida albicans. This was done by measuring the zone of inhibition of the disinfectants on the tested organisms. The results showed that Savlon was very effective ...

  8. Microbial contamination of disinfectant solutions in some health care ...

    African Journals Online (AJOL)

    Commonly used disinfectants in some health institutions in three major towns of northern Nigeria were examined for presence of bacteria contamination. For each disinfectant, stock, freshly diluted and left-over of used diluted samples were analyzed. All the stock samples were free of bacteria contaminants while 52.17% of ...

  9. HIGH-RATE DISINFECTION TECHNIQUES FOR COMBIND SEWER OVERFLOW

    Science.gov (United States)

    This paper presents high-rate disinfection technologies for combined sewer overflow (CSO). The high-rate disinfection technologies of interest are: chlorination/dechlorination, ultraviolet light irradiation (UV), chlorine dioxide (ClO2 ), ozone (O3), peracetic acid (CH3COOOH )...

  10. Peracetic Acid as a Green Disinfectant for Combined Sewer Overflows

    Science.gov (United States)

    This cooperative research and development agreement between U.S. EPA, Solvay, MSDGC, and CB&I is evaluating the potential of PAA for disinfection of Muddy Creek CSO wastewater and comparing that with sodium hypochlorite disinfection. This presentation will document the effectiven...

  11. Evaluation of hospital disinfection as a means of controlling endemic ...

    African Journals Online (AJOL)

    Evaluation of hospital environment disinfection as a means of controlling endemic nosocomial pathogens in a University Teaching Hospital in Nigeria was evaluated. Disinfectant used in the Hospital was collected from the Infection Control unit and prepared in different concentrations. The isolated bacterial species from the ...

  12. Nanomaterial Case Study: Nanoscale Silver in Disinfectant Spray (Final Report)

    Science.gov (United States)

    EPA announced the release of the final report, Nanomaterial Case Study: Nanoscale Silver in Disinfectant Spray. This report represents a case study of engineered nanoscale silver (nano-Ag), focusing on the specific example of nano-Ag as possibly used in disinfectant spr...

  13. Disinfection studies of Nahar (Mesua ferrea) seed kernel oil using ...

    African Journals Online (AJOL)

    GREGORY

    2011-12-16

    Dec 16, 2011 ... with a k value of -0.040. Key words: Nahar (Mesua ferrea) seed kernel oil, extraction, gum Arabic, disinfection, kinetics. INTRODUCTION. Disinfection plays a key role in the reclamation and reuse of wastewater for eliminating infectious diseases, this, in part, augments domestic water supply and decreases ...

  14. Candida auris: Disinfectants and Implications for Infection Control.

    Science.gov (United States)

    Ku, Tsun S N; Walraven, Carla J; Lee, Samuel A

    2018-01-01

    Candida auris is a rapidly emerging pathogen and is able to cause severe infections with high mortality rates. It is frequently misidentified in most clinical laboratories, thus requiring more specialized identification techniques. Furthermore, several clinical isolates have been found to be multidrug resistant and there is evidence of nosocomial transmission in outbreak fashion. Appropriate infection control measures will play a major role in controlling the management and spread of this pathogen. Unfortunately, there are very few data available on the effectiveness of disinfectants against C. auris . Chlorine-based products appear to be the most effective for environmental surface disinfection. Other disinfectants, although less effective than chlorine-based products, may have a role as adjunctive disinfectants. A cleaning protocol will also need to be established as the use of disinfectants alone may not be sufficient for maximal decontamination of patient care areas. Furthermore, there are fewer data on the effectiveness of antiseptics against C. auris for patient decolonization and hand hygiene for healthcare personnel. Chlorhexidine gluconate has shown some efficacy in in vitro studies but there are reports of patients with persistent colonization despite twice daily body washes with this disinfectant. Hand hygiene using soap and water, with or without chlorhexidine gluconate, may require the subsequent use of alcohol-based hand sanitizer for maximal disinfection. Further studies will be needed to validate the currently studied disinfectants for use in real-world settings.

  15. Candida auris: Disinfectants and Implications for Infection Control

    Directory of Open Access Journals (Sweden)

    Tsun S. N. Ku

    2018-04-01

    Full Text Available Candida auris is a rapidly emerging pathogen and is able to cause severe infections with high mortality rates. It is frequently misidentified in most clinical laboratories, thus requiring more specialized identification techniques. Furthermore, several clinical isolates have been found to be multidrug resistant and there is evidence of nosocomial transmission in outbreak fashion. Appropriate infection control measures will play a major role in controlling the management and spread of this pathogen. Unfortunately, there are very few data available on the effectiveness of disinfectants against C. auris. Chlorine-based products appear to be the most effective for environmental surface disinfection. Other disinfectants, although less effective than chlorine-based products, may have a role as adjunctive disinfectants. A cleaning protocol will also need to be established as the use of disinfectants alone may not be sufficient for maximal decontamination of patient care areas. Furthermore, there are fewer data on the effectiveness of antiseptics against C. auris for patient decolonization and hand hygiene for healthcare personnel. Chlorhexidine gluconate has shown some efficacy in in vitro studies but there are reports of patients with persistent colonization despite twice daily body washes with this disinfectant. Hand hygiene using soap and water, with or without chlorhexidine gluconate, may require the subsequent use of alcohol-based hand sanitizer for maximal disinfection. Further studies will be needed to validate the currently studied disinfectants for use in real-world settings.

  16. Sewage disinfection towards protection of drinking water resources.

    Science.gov (United States)

    Kolch, A

    2000-01-01

    Wastewater applied in agriculture for irrigation could replace the use of natural drinking-water resources. With respect to high concentrations of human pathogens wastewater has to be disinfected prior to use. This paper introduces disinfection methods with emphasis on UV irradiation.

  17. Endoscope disinfection and its pitfalls - requirement for retrograde surveillance cultures

    NARCIS (Netherlands)

    Buss, A. J.; Been, M. H.; Borgers, R. P.; Stokroos, I.; Melchers, W. J. G.; Peters, F. T. M.; Limburg, A. J.; Degener, J. E.

    Background and study aims: Several endoscopy-related outbreaks of infection have been reported in recent years. For early recognition of inadequate disinfection of endoscopes we designed a microbiological surveillance system to evaluate the efficacy of the cleaning and disinfection procedure, and to

  18. Disinfection of contaminated water by using solar irradiation.

    Science.gov (United States)

    Caslake, Laurie F; Connolly, Daniel J; Menon, Vilas; Duncanson, Catriona M; Rojas, Ricardo; Tavakoli, Javad

    2004-02-01

    Contaminated water causes an estimated 6 to 60 billion cases of gastrointestinal illness annually. The majority of these cases occur in rural areas of developing nations where the water supply remains polluted and adequate sanitation is unavailable. A portable, low-cost, and low-maintenance solar unit to disinfect unpotable water has been designed and tested. The solar disinfection unit was tested with both river water and partially processed water from two wastewater treatment plants. In less than 30 min in midday sunlight, the unit eradicated more than 4 log10 U (99.99%) of bacteria contained in highly contaminated water samples. The solar disinfection unit has been field tested by Centro Panamericano de Ingenieria Sanitaria y Ciencias del Ambiente in Lima, Peru. At moderate light intensity, the solar disinfection unit was capable of reducing the bacterial load in a controlled contaminated water sample by 4 log10 U and disinfected approximately 1 liter of water in 30 min.

  19. Recent advances in drinking water disinfection: successes and challenges.

    Science.gov (United States)

    Ngwenya, Nonhlanhla; Ncube, Esper J; Parsons, James

    2013-01-01

    Drinking water is the most important single source of human exposure to gastroenteric diseases, mainly as a result of the ingestion of microbial contaminated water. Waterborne microbial agents that pose a health risk to humans include enteropathogenic bacteria, viruses, and protozoa. Therefore, properly assessing whether these hazardous agents enter drinking water supplies, and if they do, whether they are disinfected adequately, are undoubtedly aspects critical to protecting public health. As new pathogens emerge, monitoring for relevant indicator microorganisms (e.g., process microbial indicators, fecal indicators, and index and model organisms) is crucial to ensuring drinking water safety. Another crucially important step to maintaining public health is implementing Water Safety Plans (WSPs), as is recommended by the current WHO Guidelines for Drinking Water Quality. Good WSPs include creating health-based targets that aim to reduce microbial risks and adverse health effects to which a population is exposed through drinking water. The use of disinfectants to inactivate microbial pathogens in drinking water has played a central role in reducing the incidence of waterborne diseases and is considered to be among the most successful interventions for preserving and promoting public health. Chlorine-based disinfectants are the most commonly used disinfectants and are cheap and easy to use. Free chlorine is an effective disinfectant for bacteria and viruses; however, it is not always effective against C. parvum and G. lamblia. Another limitation of using chlorination is that it produces disinfection by-products (DBPs), which pose potential health risks of their own. Currently, most drinking water regulations aggressively address DBP problems in public water distribution systems. The DBPs of most concern include the trihalomethanes (THMs), the haloacetic acids (HAAs), bromate, and chlorite. However, in the latest edition of the WHO Guidelines for Drinking Water Quality

  20. Impact of disinfection on drinking water biofilm bacterial community.

    Science.gov (United States)

    Mi, Zilong; Dai, Yu; Xie, Shuguang; Chen, Chao; Zhang, Xiaojian

    2015-11-01

    Disinfectants are commonly applied to control the growth of microorganisms in drinking water distribution systems. However, the effect of disinfection on drinking water microbial community remains poorly understood. The present study investigated the impacts of different disinfectants (chlorine and chloramine) and dosages on biofilm bacterial community in bench-scale pipe section reactors. Illumina MiSeq sequencing illustrated that disinfection strategy could affect both bacterial diversity and community structure of drinking water biofilm. Proteobacteria tended to predominate in chloraminated drinking water biofilms, while Firmicutes in chlorinated and unchlorinated biofilms. The major proteobacterial groups were influenced by both disinfectant type and dosage. In addition, chloramination had a more profound impact on bacterial community than chlorination. Copyright © 2015. Published by Elsevier B.V.

  1. Characterization of coagulase-negative staphylococcus species from cows' milk and environment based on bap, icaA, and mecA genes and phenotypic susceptibility to antimicrobials and teat dips.

    Science.gov (United States)

    Piessens, V; De Vliegher, S; Verbist, B; Braem, G; Van Nuffel, A; De Vuyst, L; Heyndrickx, M; Van Coillie, E

    2012-12-01

    The aim of this study was to investigate whether the main coagulase-negative staphylococci (CNS) species involved in bovine intramammary infections (IMI) possess specific characteristics that promote colonization of the udder. Virulence markers associated with biofilm formation, antimicrobial resistance, and biocide tolerance were compared between typically contagious CNS species (Staphylococcus chromogenes, Staphylococcus epidermidis, Staphylococcus haemolyticus, and Staphylococcus simulans) and those rarely causing IMI (Staphylococcus sciuri, Staphylococcus equorum, and others) to find possible associations with pathogenicity. Coagulase-negative staphylococci isolates (n=366) belonging to 22 different species were analyzed by PCR for the presence of the biofilm-associated genes bap and icaA, and the methicillin resistance gene mecA. A selection of 82 isolates was additionally tested for their susceptibility to 5 antibiotics and 2 commercial teat dip products. Minimum inhibitory concentrations of antimicrobials were determined by Etest (AB bioMérieux, Marcy l'Etoile, France), and a microdilution method was optimized to determine minimum biocidal concentrations of teat dips. The bap, icaA, and mecA genes were detected significantly more in isolates from CNS species typically living in the cows' environment than in isolates from IMI-causing species. Antimicrobial resistance was mainly against erythromycin (23%) or oxacillin (16%), and was detected more often in the environmental species. The isolates least susceptible to the teat dips belonged to the IMI-causing species Staph. chromogenes and Staph. simulans. We concluded that carriage of biofilm genes and antimicrobial resistance were not associated with the ability to colonize the mammary gland because free-living CNS species constituted a more significant reservoir of biofilm and resistance determinants than did IMI-causing species. In contrast, increased tolerance to biocides may favor the establishment of

  2. Disinfection of drinking water by ultraviolet light

    International Nuclear Information System (INIS)

    Anon.

    1977-01-01

    It is no longer mandatory that a given residue of chlorine is present in drinking water and this has led to interest in the use of ultraviolet radiation for disinfection of water in large public waterworks. After a brief discussion of the effect of ultraviolet radiation related to wavelength, the most usual type of irradiation equipment is briefly described. Practioal considerations regarding the installation, such as attenuation of the radiation due to water quality and deposits are presented. The requirements as to dose and residence time are also discussed and finally it is pointed out that hydraulic imperfections can reduce the effectiveness drastically. (JIW)Ψ

  3. The role of surface disinfection in infection prevention

    Science.gov (United States)

    Gebel, Jürgen; Exner, Martin; French, Gary; Chartier, Yves; Christiansen, Bärbel; Gemein, Stefanie; Goroncy-Bermes, Peter; Hartemann, Philippe; Heudorf, Ursel; Kramer, Axel; Maillard, Jean-Yves; Oltmanns, Peter; Rotter, Manfred; Sonntag, Hans-Günther

    2013-01-01

    Background: The Rudolf Schuelke Foundation addresses topics related to hygiene, infection prevention and public health. In this context a panel of scientists from various European countries discussed “The Role of Surface Disinfection in Infection Prevention”. The most important findings and conclusions of this meeting are summarised in the present consensus paper. Aim: Although the relevance of surface disinfection is increasingly being accepted, there are still a number of issues which remain controversial. In particular, the following topics were addressed: Transferral of microbes from surface to patients as a cause of infection, requirements for surface disinfectants, biocidal resistance and toxicity, future challenges. Methods and findings: After discussion and review of current scientific literature the authors agreed that contaminated surfaces contribute to the transmission of pathogens and may thus pose an infection hazard. Targeted surface disinfection based on a risk profile is seen as an indispensable constituent in a multibarrier approach of universal infection control precautions. Resistance and cross-resistance depend on the disinfectant agent as well as on the microbial species. Prudent implementation of surface disinfection regimens tested to be effective can prevent or minimize adverse effects. Conclusions: Disinfection must be viewed as a holistic process. There is a need for defining standard principles for cleaning and disinfection, for ensuring compliance with these principles by measures such as written standard operating procedures, adequate training and suitable audit systems. Also, test procedures must be set up in order to demonstrate the efficacy of disinfectants including new application methods such as pre-soaked wipes for surface disinfection. PMID:23967396

  4. A pilot solar water disinfecting system: performance analysis and testing

    Energy Technology Data Exchange (ETDEWEB)

    Saitoh, T.S.; El-Ghetany, H.H. [Tohoku University, Sendai (Japan). Dept. of Aeronautics and Space Engineering

    2002-07-01

    In most countries, contaminated water is the major cause of most water-borne diseases. Disinfection of water may be accomplished by a number of different physical-chemical treatments including direct application of thermal energy, chemical and filtration techniques. Solar energy also can be used effectively in this field because inactivation of microorganisms is done either by heating water to a disinfecting temperature or by exposing it to ultraviolet solar radiation. A pilot solar system for disinfecting contaminated water is designed, constructed and tested. Investigations are carried out to evaluate the performance of a wooden hot box solar facility as a solar disinfectant. Experimental data show that solar energy is viable for the disinfection process. A solar radiation model is presented and compared with the experimental data. A mathematical model of the solar disinfectant is also presented. The governing equations are solved numerically via the fourth-order Runge-Kutta method. The effects of environmental conditions (ambient temperature, wind speed, solar radiation, etc.) on the performance of the solar disinfectant are examined. Results showed that the system is affected by ambient temperature, wind speed, ultraviolet solar radiation intensity, the turbidity of the water, the quantity of water exposed, the contact area between the transparent water container in the solar disinfectant and the absorber plate as well as the geometrical parameters of the system. It is pointed out that for partially cloudy conditions with a low ambient temperature and high wind speeds, the thermal efficiency of the solar disinfectant is at a minimum. The use of solar energy for the disinfection process will increase the productivity of the system while completely eliminating the coliform group bacteria at the same time. (author)

  5. The role of surface disinfection in infection prevention

    Directory of Open Access Journals (Sweden)

    Gebel, Jürgen

    2013-04-01

    Full Text Available [english] Background: The Rudolf Schuelke Foundation addresses topics related to hygiene, infection prevention and public health. In this context a panel of scientists from various European countries discussed “The Role of Surface Disinfection in Infection Prevention”. The most important findings and conclusions of this meeting are summarised in the present consensus paper.Aim: Although the relevance of surface disinfection is increasingly being accepted, there are still a number of issues which remain controversial. In particular, the following topics were addressed: Transferral of microbes from surface to patients as a cause of infection, requirements for surface disinfectants, biocidal resistance and toxicity, future challenges.Methods and findings: After discussion and review of current scientific literature the authors agreed that contaminated surfaces contribute to the transmission of pathogens and may thus pose an infection hazard. Targeted surface disinfection based on a risk profile is seen as an indispensable constituent in a multibarrier approach of universal infection control precautions. Resistance and cross-resistance depend on the disinfectant agent as well as on the microbial species. Prudent implementation of surface disinfection regimens tested to be effective can prevent or minimize adverse effects.Conclusions: Disinfection must be viewed as a holistic process. There is a need for defining standard principles for cleaning and disinfection, for ensuring compliance with these principles by measures such as written standard operating procedures, adequate training and suitable audit systems. Also, test procedures must be set up in order to demonstrate the efficacy of disinfectants including new application methods such as pre-soaked wipes for surface disinfection.

  6. 9 CFR 52.7 - Disinfection of premises, conveyances, and materials.

    Science.gov (United States)

    2010-01-01

    ... cleaning and disinfection, unless an official pseudorabies epidemiologist determines that a shorter or... and disinfection, except for cleaning and disinfection of the conveyances used to transport the swine... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Disinfection of premises, conveyances...

  7. 9 CFR 55.4 - Disinfection of premises, conveyances, and materials.

    Science.gov (United States)

    2010-01-01

    ... paid will be responsible for expenses incurred in connection with the cleaning and disinfection, except that APHIS or a State will pay for cleaning and disinfection of the conveyances used to transport the... disinfecting premises when the procedures needed to conduct effective cleaning and disinfection are unusually...

  8. Fine Sprays for Disinfection within Healthcare

    Directory of Open Access Journals (Sweden)

    G Nasr

    2016-09-01

    Full Text Available Problems exist worldwide with Hospital Acquired Infections (HAI's. The Spray Research Group (SRG have been working with relevant industries in developing a product which can provide a delivery system for treatment chemicals for surfaces, including the design and testing of a novel Spill-Return Atomiser (SRA for this purpose. A comprehensive description of this atomiser has already been given. This paper reports on a new application of this atomiser and discusses the problem of spray coating for disinfection that has been considered very little in previous work. The related spray coating performance tests in developing the product are thus provided. The experimental work includes determining the required spray duration and the coverage area produced by different sprays, including the analysis of the effects of atomiser positions, configurations, and the required number of atomisers. Comparison is made with the efficacy of an ultrasonic gas atomiser that is currently used for this purpose. The investigation has found that the utilisation of fine sprays (10μm>D32>25μm at high liquid pressure (<12MPa and low flow rates (<0.3 l/min is suitable for surface disinfection in healthcare applications (i.e. MRSA, VRSA etc.

  9. Cleansing and Disinfection in the Food Industry

    Directory of Open Access Journals (Sweden)

    Ruhtan Baskaya

    2009-02-01

    Full Text Available In the applications of industrial hygiene, it is of utmost importance to define the potential risk factors in the business enterprise in question, to pay sufficient consideration to those factors, and to spend every effort for their checking and elimination. In that sense, cleansing and disinfection applications have a basic importance. Food hygiene covers all the efforts spent in order to ensure the proper conditions for the production of healthy food at every stage of the production process, extending from the farm to the table. Cleansing is the removal of the dirt or food leftovers found on the tools and equipment contacting food, and preventing their conversion into a convenient millieu for the reproduction of microorganisms. Cleansing is the process of removing not only the visible dirts and leftovers, but also a large part of the visible microorganisms. Disinfection is applied after cleansing; it is the process of disintegration of microorganisms which can cause contamination, or reduction of those microorganisms to minimum levels so that they can not create any harmful effects. [TAF Prev Med Bull 2009; 8(1.000: 93-106

  10. Wastewater disinfection with peracetic acid and UV

    International Nuclear Information System (INIS)

    Caretti, C.; Lubello, C.

    2001-01-01

    Was investigated the synergy between UV and peracetic acid (PAA) through a five months on-site experimental study in a pilot plant fed by the secondary effluent of the central wastewater treatment plant of Pistoia, Italy. This experiment is a part of a larger research project on advanced treatment for municipal wastewater reuse in agriculture. Because of Italy's strict limits on unrestricted wastewater reuse in agriculture (2 CFU total coliform/100 ml), a very high degree of disinfection is necessary. In the investigated experimental conditions, it has been impossible to meet such values through an exclusive use of UV irradiation (the UV unit reaches at most 4 Log inactivation). Low levels of PAA greatly enhance the decline of indicator levels, but higher unsustainable doses are required to hit the Italian limit. Through a poor amount of information on the subject was available in literature, it was tried to find out how the disinfection efficiency could improve by simultaneously using UV and PAA. It was found out that a combined treatment is satisfactory and that it is more advantage of the hydroxyl radicals formation due to the PAA photo lysis. The application of 2 ppm of PAA with an UV dose of 192 mWscm - 2 is enough to meet the Italian limit [it

  11. Quality control of disinfection in ultrasonic baths

    Energy Technology Data Exchange (ETDEWEB)

    Schoene, H. [Technical University Dresden (Germany). Faculty of Mechanical Engineering; Jatzwauk, L. [University Hospital of the Technical University Dresden (Germany). Abt. Krankenhaushygiene

    2002-07-01

    Numerous investigations under laboratory conditions confirmed the microbicidal efficacy of ultrasonication. Morphological destruction was shown on bacteria and fungi as well as on different virus species. Ultrasonic treatment seems to increase the effect of different antibiotics and disinfectants. Reasons for this synergism are largely unknown and uninvestigated, but the active principle seems to bee the dispersing effect of ultrasonication in combination with the destruction of cell wall or cell membrane. Unfortunately no validation of test conditions exists for most of these investigations, regarding intensity and frequency of ultrasonic waves, temperature of liquid medium and measurement of cavitation which is an essential part of physical and chemical effects in ultrasonic baths. In contrast to most laboratory experiments sound density of ultrasound for treatment of medical instruments is below 1 W/cm{sup 2} because instruments will be destroyed under stronger ultrasonic conditions. The frequency is below 50 KHz. This paper describes bactericidal and fungicidal effects of low- intensity-ultrasonication and its synergistical support to chemical disinfection. (orig.)

  12. Effects of disinfecting alginate impressions on the scratch hardness of stone models.

    Science.gov (United States)

    Hiraguchi, Hisako; Nakagawa, Hisami; Wakashima, Mitsuru; Miyanaga, Kohichi; Saigo, Masataka; Nishiyama, Minoru

    2006-03-01

    This study investigated the effects of disinfecting alginate impressions on the scratch depth of resultant stone models. Eleven brands of alginate impression material and two disinfectants, 1% sodium hypochlorite and 2% glutaraldehyde, were used. Impressions were immersed in disinfectant solutions or stored in sealed bags after spraying with disinfectants, and then poured with a type V dental stone. The scratch depth of the stone model obtained from disinfected impression was measured. The storage of alginate impressions after spraying with disinfectants did not increase the scratch depth of resultant stone models. However, the effect of immersion in disinfectants on scratch depth varied with the brand of the alginate impression material.

  13. Inactivation model for disinfection of biofilms in drinking water

    International Nuclear Information System (INIS)

    Karlicki, A.; O'Leary, K.C.; Gagnon, G.A.

    2002-01-01

    The purpose of the project was to investigate experimentally the effects of free chlorine, monochloramine and chlorine dioxide on the removal of biofilm growth in water as it applies to drinking water in distribution systems. In particular, biofilm kill for a particular dosage of disinfectant was measured as a function of time for each disinfectant over a range of disinfectant concentrations. These results were used to formulate concentration-time (Ct) inactivation values for each disinfectant to compare the efficacy of the three disinfectants for biofilm control. The biofilm reactor system consisted of a 125 mL columns, each containing tightly packed 3 mm glass beads on which heterotrophic bacterial biofilm is established. Following an initial biofilm inoculation period, the glass beads were removed from the columns and placed into glass jars for disinfection with free chlorine, monochloramine and chlorine dioxide. Cell counts were determined on a time series basis with the goal of achieving a Ct inactivation model that is similar to models presently used for inactivation of suspended cells. Ultimately this research could be used to develop a rationale method for setting regulatory values for secondary disinfection in drinking water distribution systems, which presently in only a few states and provinces. (author)

  14. ASSESSMENT OF ACTION OF DISINFECTANTS AGAINST LISTERIA MONOCYTOGENES BIOFILMS

    Directory of Open Access Journals (Sweden)

    T. K. CABEÇA

    2008-12-01

    Full Text Available

    The purpose of this study was to assess the action of various disinfectants used in food industry against biofilm cells of Listeria monocytogenes formed on stainless steel surfaces during 24, 72 and 120 hours. Numbers of viable biofilm cells decreased after treatment with all the tested disinfectants (iodine, biguanide, quaternary ammonium compounds, peracetic acid and sodium hypochlorite. Sodium hypochlorite was the most effective disinfectant against the biofilm cells, while biguanide and iodine were the least. Scanning electron microscopy observations demonstrated attached cells on stainless steel surfaces after treatment with all the disinfectants. These observations showed that microorganisms were not completely removed from stainless steel surfaces after treatment with the disinfectants, however, the attachment did not means the viability of remaining cells. The biofilm age in hours (24, 72 and 120 had no apparent influence on resistance of microbiological cells to the disinfectants under study. In conclusion biofilm cells of L. monocytogenes can withstand disinfectants action.

  15. Wettability changes in polyether impression materials subjected to immersion disinfection.

    Science.gov (United States)

    Shetty, Shweta; Kamat, Giridhar; Shetty, Rajesh

    2013-07-01

    Disinfection of impression materials prevents cross-contamination; however, the disinfectants may alter the wettability property. The purpose of this investigation was to evaluate the wettability changes of polyether impression material after immersing in four different chemical disinfectant solutions for a period of 10 min and 30 min, respectively. A total of 45 samples of polyether dental impression material (Impregum soft, 3MESPE, St. Paul, MN, USA) were randomly divided into nine groups with five specimens each. Each specimen was disc shaped, flat of 32 mm diameter and 3 mm thickness. The samples were immersed in four disinfectant solutions: 2% Glutaraldehyde, 5% sodium hypochlorite, 0.05% iodophor, and 5.25% phenol for 10 min and 30 min, respectively. The control was without disinfection. Wettability of the samples was assessed by measuring the contact angle by using the Telescopic Goniometer. Data were subjected to analysis of variance (Fisher's test) and Tukey's post hoc test for multiple comparisons at 5% level of significance. The contact angle of 20.21° ± 0.22° were recorded in the control samples. After 10 min, the samples that were immersed in 5% sodium hypochlorite and 5.25% phenol showed significant statistical increase in the contact angle as compared to the control (P polyether material. Within the limitations of the study, 2% glutaraldehyde proved safe for 10 min of immersion disinfection while 0.05% iodophor holds promise as an effective disinfectant without affecting the wettability of the material.

  16. Efficacy of a variety of disinfectants against Listeria spp.

    Science.gov (United States)

    Best, M; Kennedy, M E; Coates, F

    1990-02-01

    The efficacy of 14 disinfectants against Listeria innocua and two strains of Listeria monocytogenes in the presence of organic matter was studied. Quantitative efficacy tests were used. Many of the disinfectants tested were not as effective on Listeria spp. when the test organisms were dried onto the surface of steel disks (carrier tests) as they were when the organisms were placed in suspension (suspension test). The presence of whole serum and milk (2% fat) further reduced the disinfectant capacities of most of the formulations studied. Only three disinfectants (povidone-iodine, chlorhexidine gluconate, and glutaraldehyde) were effective in the carrier test in the presence of serum; however, all three were ineffective when challenged with milk (2% fat). Only one solution, sodium dichloroisocyanurate, was effective in the presence of milk. All but four formulations (chloramine-T, phosphoric acid, an iodophor, and formaldehyde) were effective in the suspension tests, regardless of the organic load. L. monocytogenes was observed to be slightly more resistant to disinfection than L. innocua was. There was no difference in disinfectant susceptibility between the two strains of L. monocytogenes. These findings emphasize the need for caution in selecting an appropriate disinfectant for use on contaminated surfaces, particularly in the presence of organic material.

  17. Drinking Water Supply without Use of a Disinfectant

    Science.gov (United States)

    Rajnochova, Marketa; Tuhovcak, Ladislav; Rucka, Jan

    2018-02-01

    The paper focuses on the issue of drinking water supply without use of any disinfectants. Before the public water supply network operator begins to consider switching to operation without use of chemical disinfection, initial assessment should be made, whether or not the water supply system in question is suitable for this type of operation. The assessment is performed by applying the decision algorithm. The initial assessment is followed by another decision algorithm which serves for managing and controlling the process of switching to drinking water supply without use of a disinfectant. The paper also summarizes previous experience and knowledge of this way operated public water supply systems in the Czech Republic.

  18. Sterilization, high-level disinfection, and environmental cleaning.

    Science.gov (United States)

    Rutala, William A; Weber, David J

    2011-03-01

    Failure to perform proper disinfection and sterilization of medical devices may lead to introduction of pathogens, resulting in infection. New techniques have been developed for achieving high-level disinfection and adequate environmental cleanliness. This article examines new technologies for sterilization and high-level disinfection of critical and semicritical items, respectively, and because semicritical items carry the greatest risk of infection, the authors discuss reprocessing semicritical items such as endoscopes and automated endoscope reprocessors, endocavitary probes, prostate biopsy probes, tonometers, laryngoscopes, and infrared coagulation devices. In addition, current issues and practices associated with environmental cleaning are reviewed. Copyright © 2011. Published by Elsevier Inc.

  19. Enhanced photocatalytic disinfection of indoor air

    Energy Technology Data Exchange (ETDEWEB)

    Vohra, Amit; Goswami, D.Y.; Deshpande, D.A.; Block, S.S. [Solar Energy and Energy Conversion Laboratory, Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, FL 32611 (United States)

    2006-04-18

    A silver ion doped TiO{sub 2} based photocatalyst, with improved destruction of airborne microbes, has been developed. The performance of the silver ion doped photocatalyst is demonstrated using a catalyst coated filter in a recirculating air experimental facility. Bacillus cereus, Staphylococcus aureus, Escherichia coli, Aspergillus niger, and MS2 Bacteriophage have been used as indexes to demonstrate the high disinfection efficiency of the enhanced photocatalysis process. The microbial destruction performance of the enhanced photocatalyst is found to be an order of magnitude higher than that of a conventional TiO{sub 2} photocatalyst. The process of enhanced photocatalysis can thus be used effectively against high concentrations of airborne microorganisms, making it an attractive option as a defense against bio-terrorism. (author)

  20. Antimicrobial-Coated Granules for Disinfecting Water

    Science.gov (United States)

    Akse, James R.; Holtsnider, John T.; Kliestik, Helen

    2011-01-01

    Methods of preparing antimicrobialcoated granules for disinfecting flowing potable water have been developed. Like the methods reported in the immediately preceding article, these methods involve chemical preparation of substrate surfaces (in this case, the surfaces of granules) to enable attachment of antimicrobial molecules to the surfaces via covalent bonds. A variety of granular materials have been coated with a variety of antimicrobial agents that include antibiotics, bacteriocins, enzymes, bactericides, and fungicides. When employed in packed beds in flowing water, these antimicrobial-coated granules have been proven effective against gram-positive bacteria, gram-negative bacteria, fungi, and viruses. Composite beds, consisting of multiple layers containing different granular antimicrobial media, have proven particularly effective against a broad spectrum of microorganisms. These media have also proven effective in enhancing or potentiating the biocidal effects of in-line iodinated resins and of very low levels of dissolved elemental iodine.

  1. Effects of different cavity‑disinfectants and potassium titanyl ...

    African Journals Online (AJOL)

    disinfectants and potassium titanyl phosphate (KTP) laser on microtensile bond strength to primary dentin. Chlorhexidine (CHX), propolis (PRO), ozonated water (OW), gaseous ozone (OG) and KTP laser were used for this purpose. Methodology: ...

  2. Drinking water disinfection by means of ultraviolet radiation

    International Nuclear Information System (INIS)

    Gelzhaeuser, P.; Bewig, F.; Holm, K.; Kryschi, R.; Reich, G.; Steuer, W.

    1985-01-01

    The book presents all lectures held during a course at Technical Academy Esslingen, on September 10, 1985, on the subject of 'Drinking water disinfection by means of ultraviolet radiation'. The methods hitherto used for disinfection are no longer suitable because of the increasing amounts of organic pollutants found in the untreated water, and because of the necessity to make drinking water disinfection less expensive, non-polluting and thus environmentally compatible. U.V. irradiation is a method allowing technically simple and safe disinfection of the water, and also does not have any effect on the natural taste of the drinking water. The lectures presented discuss all aspects of the method, the equipment, and the performance of irradiation systems in practice. (orig./PW) [de

  3. Waterline ATS B. globigii spore water disinfection data

    Data.gov (United States)

    U.S. Environmental Protection Agency — Disinfection of B. globigii spores (a non-pathogenic surrogate for B. anthracis) in clean and dirty water using the ATS-Waterline system, which uses ultraviolet...

  4. Effect of ultrasonic pretreatment on purified water disinfection

    International Nuclear Information System (INIS)

    Simon Andreu, P.; Lardin Mifsut, C.; Vergara Romero, L.; Polo Canas, P. M.; Perez Sanchez, P.; Rancano Perez, A.

    2009-01-01

    Due to the importance of a suitable water disinfection in order to insure a pollutant effect minimization against environment, this work has been carried out to determine how can affect an ultrasonic pre-treatment upon disinfection step. It has been confirmed the ultrasonic disintegration of bacterial cells in treated water and disinfectant power of treatment by itself, which is not enough to be used as a single method in water disinfection. It has also been proved that from a technical and economical point of view the combination of UV and ultrasound improves the UV treatment performance. Finally, it has been detected that an ultrasonic pre-treatment increases chlorination effectiveness, however the high cost in this combination makes it unfeasible of industrial scale. (Author) 6 refs

  5. Effect of hydrodynamic cavitation on zooplankton: A tool for disinfection

    Digital Repository Service at National Institute of Oceanography (India)

    Sawant, S.S.; Anil, A.C.; Venkat, K.; Gaonkar, C.; Kolwalkar, J.; Khandeparker, L.; Desai, D.V.; Mahulkar, A.V.; Ranade, V.V.; Pandit, A.B.

    by individual oscillating cavity, cell wall strength and geometrical and operating parameters of cavitation device. Theoretical model for quantifying the cavitationally generated turbulent shear and extent of microbial disinfection has been developed...

  6. Assessment of apparent effectiveness of chemical egg disinfectants ...

    African Journals Online (AJOL)

    Aquaculture holds the potential to supplement catches as well as produce seed ... re-circulating incubation system at the National Aquaculture Center, Domasi, Malawi. ... Key words: Egg, disinfectants, incubation, recirculation, hatchability, egg ...

  7. development of an automated batch-process solar water disinfection

    African Journals Online (AJOL)

    user

    This work presents the development of an automated batch-process water disinfection system ... Locally sourced materials in addition to an Arduinomicro processor were used to control ..... As already mentioned in section 3.1.1, a statistical.

  8. IDENTIFICATION OF TI02/UV DISINFECTION BYPRODUCTS IN DRINKING WATER

    Science.gov (United States)

    Due to concern over the presence of trihalomethanes (THMs) and other chlorinated byproducts in chlorinated drinking water, alternative disinfection methods are being explored. One of the alternative treatment methods currently being evaluated for potential use with small systems ...

  9. Selecting a Sustainable Disinfection Technique for Wastewater Reuse Projects

    Directory of Open Access Journals (Sweden)

    Jorge Curiel-Esparza

    2014-09-01

    Full Text Available This paper presents an application of the Analytical Hierarchy Process (AHP by integrating a Delphi process for selecting the best sustainable disinfection technique for wastewater reuse projects. The proposed methodology provides project managers a tool to evaluate problems with multiple criteria and multiple alternatives which involve non-commeasurable decision criteria, with expert opinions playing a major role in the selection of these treatment technologies. Five disinfection techniques for wastewater reuse have been evaluated for each of the nine criteria weighted according to the opinions of consulted experts. Finally, the VIKOR method has been applied to determine a compromise solution, and to establish the stability of the results. Therefore, the expert system proposed to select the optimal disinfection alternative is a hybrid method combining the AHP with the Delphi method and the VIKOR technique, which is shown to be appropriate in realistic scenarios where multiple stakeholders are involved in the selection of a sustainable disinfection technique for wastewater reuse projects.

  10. Mimicking disinfection and drying of biofilms in contaminated endoscopes

    NARCIS (Netherlands)

    Kovaleva, J.; Degener, J. E.; van der Mei, H. C.

    2010-01-01

    The effects of peracetic acid-based (PAA) disinfectant with, and without, additional drying on Candida albicans, Candida parapsilosis, Pseudomonas aeruginosa and Stenotrophomonas maltophilia, isolated from contaminated flexible endoscopes, in single-and dual-species biofilms were studied. Biofilms

  11. Selection Criteria for Water Disinfection Techniques in Agricultural Practices

    OpenAIRE

    Haute, Sam van; Sampers, Imca; Jacxsens, Liesbeth; Uyttendaele, Mieke

    2013-01-01

    This paper comprises a selection tool for water disinfection methods for fresh produce pre- and postharvest practices. A variety of water disinfection technologies is available on the market and no single technology is the best choice for all applications. It can be difficult for end users to choose the technology that is best fit for a specific application. Therefore, the different technologies were characterized in order to identify criteria that influence the suitability of a technology fo...

  12. Methodological approaches to disinfection of human hepatitis B virus.

    OpenAIRE

    Prince, D L; Prince, H N; Thraenhart, O; Muchmore, E; Bonder, E; Pugh, J

    1993-01-01

    Three commercial disinfectants (two quaternary formulations and one phenolic) were tested against human hepatitis B virus (HHBV). The treated virus was assayed for infectivity by the chimpanzee assay and for morphological alteration by the Morphological Alteration and Disintegration Test. The same agents were tested against duck hepatitis B virus in a duck hepatocyte infectivity assay. It is apparent that human and duck hepatitis viruses were relatively susceptible to disinfection, becoming n...

  13. Composting of gamma-radiation disinfected sewage sludge

    International Nuclear Information System (INIS)

    Kawakami, W.; Hashimoto, S.; Watanabe, H.; Nishimura, K.; Watanabe, H.; Ito, H.; Takehisa, M.

    1981-01-01

    The composting of radiation disinfected sewage sludge has been studied since 1978, aiming to present a new process of sludge composting for agricultural uses. This process is composed of two steps: irradiation step to disinfect sludge, and composting step to remove odor and easily decomposable organics in sludge. In this paper, the gamma-irradiation effect on sludge cake and composting condition of irradiated sludge are discussed. (author)

  14. A Review of Heterogeneous Photocatalysis for Water and Surface Disinfection

    Directory of Open Access Journals (Sweden)

    John Anthony Byrne

    2015-03-01

    Full Text Available Photo-excitation of certain semiconductors can lead to the production of reactive oxygen species that can inactivate microorganisms. The mechanisms involved are reviewed, along with two important applications. The first is the use of photocatalysis to enhance the solar disinfection of water. It is estimated that 750 million people do not have accessed to an improved source for drinking and many more rely on sources that are not safe. If one can utilize photocatalysis to enhance the solar disinfection of water and provide an inexpensive, simple method of water disinfection, then it could help reduce the risk of waterborne disease. The second application is the use of photocatalytic coatings to combat healthcare associated infections. Two challenges are considered, i.e., the use of photocatalytic coatings to give “self-disinfecting” surfaces to reduce the risk of transmission of infection via environmental surfaces, and the use of photocatalytic coatings for the decontamination and disinfection of medical devices. In the final section, the development of novel photocatalytic materials for use in disinfection applications is reviewed, taking account of materials, developed for other photocatalytic applications, but which may be transferable for disinfection purposes.

  15. Efficiency of hydrogen peroxide in improving disinfection of ICU rooms.

    Science.gov (United States)

    Blazejewski, Caroline; Wallet, Frédéric; Rouzé, Anahita; Le Guern, Rémi; Ponthieux, Sylvie; Salleron, Julia; Nseir, Saad

    2015-02-02

    The primary objective of this study was to determine the efficiency of hydrogen peroxide (H₂O₂) techniques in disinfection of ICU rooms contaminated with multidrug-resistant organisms (MDRO) after patient discharge. Secondary objectives included comparison of the efficiency of a vaporizator (HPV, Bioquell) and an aerosolizer using H₂O₂, and peracetic acid (aHPP, Anios) in MDRO environmental disinfection, and assessment of toxicity of these techniques. This prospective cross-over study was conducted in five medical and surgical ICUs located in one University hospital, during a 12-week period. Routine terminal cleaning was followed by H₂O₂ disinfection. A total of 24 environmental bacteriological samplings were collected per room, from eight frequently touched surfaces, at three time-points: after patient discharge (T0), after terminal cleaning (T1) and after H₂O₂ disinfection (T2). In total 182 rooms were studied, including 89 (49%) disinfected with aHPP and 93 (51%) with HPV. At T0, 15/182 (8%) rooms were contaminated with at least 1 MDRO (extended spectrum β-lactamase-producing Gram-negative bacilli 50%, imipenem resistant Acinetobacter baumannii 29%, methicillin-resistant Staphylococcus aureus 17%, and Pseudomonas aeruginosa resistant to ceftazidime or imipenem 4%). Routine terminal cleaning reduced environmental bacterial load (P disinfection efficiency.

  16. Radiation disinfection of sewage sludge and composting of the irradiated sludge

    International Nuclear Information System (INIS)

    Hashimoto, Shoji; Nishimura, Koichi; Watanabe, Hiromasa; Kawakami, Waichiro

    1985-01-01

    In the radiation disinfected sewage sludge, its stabilization is necessary with the composting. In this disinfected sludge, there is no need of keeping it at high temperature at the cost of fermentation velocity. The fermentation velocity can thus be set to obtain its maximum value. In sewage sludge utilization of farm land, to prevent the contamination with pathogenic bacteria and the secondary pollution, the radiation disinfection of dehydrated sludge and the composting of the disinfected sludge have been studied. The disinfection effect when an electron accelerator is used for the radiation source is described. Then, the composting of the disinfected sludge is described in chemical kinetics of the microorganisms. (Mori, K.)

  17. Theoretical model for the UV disinfection system in the operating ward of PZU 'Filip Vtori'

    International Nuclear Information System (INIS)

    Ilkov, Marjan

    2010-01-01

    Here we investigate the theoretical modeling of an UV disinfection system for the operating ward in PZU 'FILIP VTORI'. As nocosomial infections pose a serious threat to patients everywhere in the world, here the disinfection of the air and the surfaces is modeled and discussed. The surfaces are disinfected with direct illumination of open UV after hours system, UV curtains, overhead disinfection, floor disinfection and disinfection of the incoming air through the ventilation/air-condition system. From the results it can be seen that the concentrations of bacteria, fungi and viruses drop significantly which in turn should give a significant drop in a number of hospital acquired infections.(Author)

  18. In vitro study on the disinfectability of two split-septum needle-free connection devices using different disinfection procedures

    Directory of Open Access Journals (Sweden)

    Engelhart, Steffen

    2015-12-01

    Full Text Available This in vitro study investigated the external disinfection of two needle-free connection devices (NFC using Octeniderm (spraying and wiping technique vs. Descoderm pads (wiping technique. The split-septum membrane of the NFC was contaminated with >10 CFU . The efficacy of the disinfection at 30 sec. exposure time was controlled by taking a swab sample and by flushing the NFC with sterile 0.9% sodium chloride solution. Disinfection with octenidine dihydrochloride 0.1 g, 1-Propanol 30.0 g, and 2-Propanol 45.0 g in solution was highly effective (CFU reduction ≥4 log against both microorganisms, whereas the use of 63.1 g 2-Propanol in 100 ml solution led to residual contamination with . Our investigation underlines that (i in clinical practice disinfection of NFCs before use is mandatory, and that (ii details of disinfection technique are of utmost importance regarding their efficacy. Our investigation revealed no significant differences between both split-septum NFC types. Clinical studies are needed to confirm a possible superiority of disinfectants with long-lasting residual antimicrobial activity.

  19. Effects of antibiotic dry-cow therapy and internal teat sealant on milk somatic cell counts and clinical and subclinical mastitis in early lactation.

    Science.gov (United States)

    Golder, H M; Hodge, A; Lean, I J

    2016-09-01

    The objective of this study was to determine the efficacy of an internal teat sealant (TS; Teatseal; Zoetis Australia, Silverwater, NSW, Australia), when used in combination with antibiotic dry-cow therapy (ADCT) administered at dry-off, on milk individual somatic cell count (ISCC), milk production and components, and the incidence of clinical and subclinical mastitis in dairy cows up to 60 d after calving, when compared with ADCT only. Multiparous Holstein, Jersey, or Holstein cross cows (n=2,200) from 8 farms in southern and eastern Australia were randomly assigned to treatment of all 4 quarters with ADCT alone or with ADCT plus TS (ADCT + TS) at dry-off in this randomized, multisite clinical trial. Individual milk yield, fat and protein percentages, and ISCC were measured at intervals of 14±3 d after calving for the first 60 d of lactation. The first measurement occurred between 10 and 24 d after calving. Clinical mastitis and health events were recorded from dry-off to 60 d of lactation. Milk samples were collected from first cases of clinical mastitis and subjected to bacteriology. Treatment and the interaction of treatment by time did not affect milk yield, ISCC weighted by milk yield, or fat and protein percentages. Treatment with ADCT + TS decreased geometric mean ISCC compared with treatment with ADCT alone over the first 60 d of lactation. Geometric mean ISCC (×10(3) cells/mL) was 32.0 [95% confidence interval (CI): 26.8 to 38.3] and 43.5 (95% CI: 36.2 to 52.1) for ADCT + TS and ADCT alone, respectively. The odds of at least 1 case of subclinical mastitis (ISCC ≥250,000 cells/mL) were 1.9 times higher (95% CI: 1.4 to 2.6) with ADCT alone in the first 60 d of lactation compared with ADCT + TS. Use of ADCT + TS reduced the estimated incidence of at least 1 case of subclinical mastitis on all 8 farms, compared with use of ADCT alone. Only 4 cows that calved 40 to 100 d after dry-off had a first case of clinical mastitis in the dry period. Five percent of

  20. The use of an internal teat sealant in combination with cloxacillin dry cow therapy for the prevention of clinical and subclinical mastitis in seasonal calving dairy cows.

    Science.gov (United States)

    Runciman, D J; Malmo, J; Deighton, M

    2010-10-01

    Cows (n=2,053) from 6 seasonally calving dairy herds were enrolled in a trial to compare the efficacy of 2 dry cow treatments. Cows received either a combination dry cow therapy of 600 mg of cloxacillin (CL) followed by an internal teat sealant (ITS) containing 2.6 g of bismuth subnitrate in all 4 quarters immediately following their final milking for the season, or only an intramammary infusion of 600 mg of CL. All cases of clinical mastitis were recorded and cultured during the first 150 d of lactation in each herd, and cow somatic cell count (SCC) was measured between 7 and 50 d postcalving. A large difference was found between treatment groups in the rate at which cows were diagnosed with clinical mastitis over the first 21 d of lactation, after which time the rate at which cows were diagnosed with clinical mastitis was similar between treatment groups. Analysis of the relative proportions of cows with clinical mastitis was performed at both the gland and cow levels. The relative risk (RR) of clinical mastitis diagnosed within 21, 30, and 100 d of calving in a gland treated with the ITS-CL combination was, respectively, 0.30 [95% confidence interval (CI)=0.21-0.44], 0.39 (0.28-0.53), and 0.58 (0.46-0.75) that of the CL group. An interaction between treatment and previous SCC was found when clinical mastitis was analyzed at the cow level. In a subset of cows that had low SCC in their previous lactation, the RR of mastitis in cows with the ITS-CL combination within 21, 30, and 100 d of calving was, respectively, 0.54 (95% CI=0.33-0.87), 0.57 (0.37-0.88), and 0.69 (0.50-0.99) that of cows that received only CL at drying off. In the subset of cows that had at least 1 high SCC in the previous lactation, the RR of mastitis in the ITS-CL combination group within 21, 30, and 100 d of calving was, respectively, 0.26 (95% CI=0.16-0.44), 0.37 (0.24-0.57), and 0.72 (0.55-0.96) that of the CL-only group. The ITS-CL combination of dry cow treatments was associated with a

  1. Overcoming the problem of residual microbial contamination in dental suction units left by conventional disinfection using novel single component suction handpieces in combination with automated flood disinfection.

    Science.gov (United States)

    Boyle, M A; O'Donnell, M J; Russell, R J; Galvin, N; Swan, J; Coleman, D C

    2015-10-01

    Decontaminating dental chair unit (DCU) suction systems in a convenient, safe and effective manner is problematic. This study aimed to identify and quantify the extent of the problems using 25 DCUs, methodically eliminate these problems and develop an efficient approach for reliable, effective, automated disinfection. DCU suction system residual contamination by environmental and human-derived bacteria was evaluated by microbiological culture following standard aspiration disinfection with a quaternary ammonium disinfectant or alternatively, a novel flooding approach to disinfection. Disinfection of multicomponent suction handpieces, assembled and disassembled, was also studied. A prototype manual and a novel automated Suction Tube Cleaning System (STCS) were developed and tested, as were novel single component suction handpieces. Standard aspiration disinfection consistently failed to decontaminate DCU suction systems effectively. Semi-confluent bacterial growth (101-500 colony forming units (CFU) per culture plate) was recovered from up to 60% of suction filter housings and from up to 19% of high and 37% of low volume suction hoses. Manual and automated flood disinfection of DCU suction systems reduced this dramatically (ranges for filter cage and high and low volume hoses of 0-22, 0-16 and 0-14CFU/plate, respectively) (P<0.0001). Multicomponent suction handpieces could not be adequately disinfected without prior removal and disassembly. Novel single component handpieces, allowed their effective disinfection in situ using the STCS, which virtually eliminated contamination from the entire suction system. Flood disinfection of DCU suction systems and single component handpieces radically improves disinfection efficacy and considerably reduces potential cross-infection and cross-contamination risks. DCU suction systems become heavily contaminated during use. Conventional disinfection does not adequately control this. Furthermore, multicomponent suction handpieces

  2. Enhanced composting of radiation disinfected sewage sludge

    International Nuclear Information System (INIS)

    Kawakami, W.; Hashimoto, S.

    1984-01-01

    Studies on isothermal composting of radiation disinfected sewage sludge and liquid chromatography of water extracts of the products were carried out. The optimum temperature and pH were around 50 deg C and 7 to 8, respectively. The repeated use of products as seeds increased the rate of CO 2 evolution. The rate reached a maximum within 10 hours and decreased rapidly, and the CO 2 evolution ceased after about 3 days. The conversion of organic carbon to carbon dioxide attained to about 40% for the repeated use of products as seeds at the optimum conditions. As long as seeds as available were used, no remarkable difference was found in the composting of unirradiated and irradiated sludges. The composting process using radiation, however, can be carried out at the optimum conditions and is expected to shorten the composting period, because it is not necessary to keep fermentation temperature higher to reduce pathogen in sludge. Liquid chromatographic studies of the products showed that low molecular components decreased and higher molecular ones increased with fermentation. An index expressing the degree of reduction of easily decomposable organics was presented. The index also showed that the optimum temperature for fermentation was 50 deg C. (author)

  3. Electron beam disinfection of sewage sludge

    International Nuclear Information System (INIS)

    Hashimoto, Shoji

    1992-01-01

    Electron beam treatment of dehydrated sewage sludge for safe reutilization was performed. Ranges of total bacterial counts and total coliforms in the sludge were from 1.5 x 10 8 to 1.6 x 10 9 and from 2.2 x 10 7 to 1.5 x 10 8 per wet gram, respectively. Total bacterial counts decreased about 5 log cycles after irradiating 5 kGy and irradiation with 2 kGy was enough to kill all coliforms in sewage sludge. The survival curves of total bacteria, obtained by irradiation in oxygen atmosphere, approached to that in nitrogen atmosphere with the increase of sludge thickness. No effects of dose rate and electron energy were found when the sludge layers were thin enough. Continuous disinfection of sewage sludge cake, with the maximum feed rate of 300 kg-sludge/hr, was successfully performed with a Cockcroft-Walton type electron accelerator, a sludge pump and a flat nozzle. (J.P.N.)

  4. Designing plasmas for chronic wound disinfection

    International Nuclear Information System (INIS)

    Nosenko, T; Shimizu, T; Morfill, G E

    2009-01-01

    Irradiation with low-temperature atmospheric-pressure plasma provides a promising method for chronic wound disinfection. To be efficient for this purpose, plasma should meet the following criteria: it should significantly reduce bacterial density in the wounded area, cause a long-term post-irradiation inhibition of bacterial growth, yet without causing any negative effect on human cells. In order to design plasmas that would satisfy these requirements, we assessed the relative contribution of different components with respect to bactericidal properties due to irradiation with argon plasma. We demonstrate that plasma-generated UV radiation is the main short-term sterilizing factor of argon plasma. On the other hand, plasma-generated reactive nitrogen species (RNS) and reactive oxygen species (ROS) cause a long-term 'after-irradiation' inhibition of bacterial growth and, therefore, are important for preventing wound recolonization with bacteria between two treatments. We also demonstrate that at certain concentrations plasma-generated RNS and ROS cause significant reduction of bacterial density, but have no adverse effect on human skin cells. Possible mechanisms of the different effects of plasma-generated reactive species on bacteria and human cells are discussed. The results of this study suggest that argon plasma for therapeutic purposes should be optimized in the direction of reducing the intensity of plasma-generated UV radiation and increasing the density of non-UV plasma products.

  5. Designing plasmas for chronic wound disinfection

    Energy Technology Data Exchange (ETDEWEB)

    Nosenko, T; Shimizu, T; Morfill, G E [Max-Planck Institute for Extraterrestrial Physics, Garching (Germany)], E-mail: tnosenko@mpe.mpg.de

    2009-11-15

    Irradiation with low-temperature atmospheric-pressure plasma provides a promising method for chronic wound disinfection. To be efficient for this purpose, plasma should meet the following criteria: it should significantly reduce bacterial density in the wounded area, cause a long-term post-irradiation inhibition of bacterial growth, yet without causing any negative effect on human cells. In order to design plasmas that would satisfy these requirements, we assessed the relative contribution of different components with respect to bactericidal properties due to irradiation with argon plasma. We demonstrate that plasma-generated UV radiation is the main short-term sterilizing factor of argon plasma. On the other hand, plasma-generated reactive nitrogen species (RNS) and reactive oxygen species (ROS) cause a long-term 'after-irradiation' inhibition of bacterial growth and, therefore, are important for preventing wound recolonization with bacteria between two treatments. We also demonstrate that at certain concentrations plasma-generated RNS and ROS cause significant reduction of bacterial density, but have no adverse effect on human skin cells. Possible mechanisms of the different effects of plasma-generated reactive species on bacteria and human cells are discussed. The results of this study suggest that argon plasma for therapeutic purposes should be optimized in the direction of reducing the intensity of plasma-generated UV radiation and increasing the density of non-UV plasma products.

  6. Sterilization and disinfection: the prevailing indifference

    International Nuclear Information System (INIS)

    Mirza, I.

    2007-01-01

    To evaluate the knowledge and attitude of health care professionals towards the process of sterilization and disinfection, and to check the adequacy of the reading material accessible to them. The study comprised of three components. In the first part, sections devoted to this subject in the popular books read by the students of operation theatre assistant course and students of diploma in general nursing were examined for adequacy and authenticity of information. In the second part, standard operating procedures were examined regarding sterilization of textile, rubber tubes of suction units and diathermy hand pieces of 20 operation theatres of three teaching hospital attached to undergraduate medical college of Punjab. In the third part of the study, working knowledge of 64 practicing operation theatre assistants and 57 practicing nurses was assessed through a questionnaire. It was found that popular books either did not contain the required information or the information provided was misleading or incorrect. Standard operating procedures for sterilization of selected items of all the operation theatres studied fell much below the standard of practice desired in the light of current knowledge and contemporary practices. Finally the working knowledge of the professionals studied was much below the bare minimum expected by the profession. There is a dire need for upgrading the knowledge and attitude of health care professionals regarding sterilization, besides improving the operation theatres sterilization procedures. (author)

  7. The Occurrence and Comparative Toxicity of Haloacetaldehyde Disinfection Byproducts in Drinking Water

    Science.gov (United States)

    The introduction of drinking water disinfection greatly reduced the incidence of waterborne diseases. However, the reaction between disinfectants and natural organic matter in the source water can lead to an unintended consequence, which is the formation of drinking water disinfe...

  8. Disinfection of stabilization pond effluent by peracetic acid and sodium hypochlorite

    Directory of Open Access Journals (Sweden)

    Negar Rezania

    2013-01-01

    Conclusions: The study demonstrated that application of combined PAA and NaOCl in disinfecting the effluent of the stabilization pond will promote the efficiency of disinfection process in inactivating the coliform group bacteria and fecal streptococci.

  9. Residual viral and bacterial contamination of surfaces after cleaning and disinfection

    NARCIS (Netherlands)

    Tuladhar, E.; Hazeleger, W.C.; Koopmans, M.; Zwietering, M.H.; Beumer, R.R.; Duizer, E.

    2012-01-01

    Environmental surfaces contaminated with pathogens can be sources of indirect transmission, and cleaning and disinfection are common interventions focused on reducing contamination levels. We determined the efficacy of cleaning and disinfection procedures for reducing contamination by noroviruses,

  10. Integrated Disinfection By-Products Mixtures Research: Concentration by Reverse Osmosis Membrane Techniques of Disinfection By-Products from Water Disinfected by Chlorination and Ozonation/Postchlorination

    Science.gov (United States)

    To conduct the health-effect studies described in subsequent articles in this series, concentrated aqueous mixtures of disinfection by-products were required for the two water treatment trains described in the preceding article (Miltner et al., 2008). To accomplish this, the fini...

  11. Clinical and cost effectiveness of eight disinfection methods for terminal disinfection of hospital isolation rooms contaminated with Clostridium difficile 027.

    Science.gov (United States)

    Doan, L; Forrest, H; Fakis, A; Craig, J; Claxton, L; Khare, M

    2012-10-01

    Clostridium difficile spores can survive in the environment for months or years, and contaminated environmental surfaces are important sources of nosocomial C. difficile transmission. To compare the clinical and cost effectiveness of eight C. difficile environmental disinfection methods for the terminal cleaning of hospital rooms contaminated with C. difficile spores. This was a novel randomized prospective study undertaken in three phases. Each empty hospital room was disinfected, then contaminated with C. difficile spores and disinfected with one of eight disinfection products: hydrogen peroxide vapour (HPV; Bioquell Q10) 350-700 parts per million (ppm); dry ozone at 25 ppm (Meditrox); 1000 ppm chlorine-releasing agent (Actichlor Plus); microfibre cloths (Vermop) used in combination with and without a chlorine-releasing agent; high temperature over heated dry atomized steam cleaning (Polti steam) in combination with a sanitizing solution (HPMed); steam cleaning (Osprey steam); and peracetic acid wipes (Clinell). Swabs were inoculated on to C. difficile-selective agar and colony counts were performed pre and post disinfection for each method. A cost-effectiveness analysis was also undertaken comparing all methods to the current method of 1000 ppm chlorine-releasing agent (Actichlor Plus). Products were ranked according to the log(10) reduction in colony count from contamination phase to disinfection. The three statistically significant most effective products were hydrogen peroxide (2.303); 1000 ppm chlorine-releasing agent (2.223) and peracetic acid wipes (2.134). The cheaper traditional method of using a chlorine-releasing agent for disinfection was as effective as modern methods. Copyright © 2012 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

  12. Selection criteria for water disinfection techniques in agricultural practices.

    Science.gov (United States)

    Haute, Sam van; Sampers, Imca; Jacxsens, Liesbeth; Uyttendaele, Mieke

    2015-01-01

    This paper comprises a selection tool for water disinfection methods for fresh produce pre- and postharvest practices. A variety of water disinfection technologies is available on the market and no single technology is the best choice for all applications. It can be difficult for end users to choose the technology that is best fit for a specific application. Therefore, the different technologies were characterized in order to identify criteria that influence the suitability of a technology for pre- or postharvest applications. Introduced criteria were divided into three principal components: (i) criteria related to the technology and which relate to the disinfection efficiency, (ii) attention points for the management and proper operation, and (iii) necessities in order to sustain the operation with respect to the environment. The selection criteria may help the end user of the water disinfection technology to obtain a systematic insight into all relevant aspects to be considered for preliminary decision making on which technologies should be put to feasibility testing for water disinfection in pre- and postharvest practices of the fresh produce chain.

  13. Microbiological evaluation of ultrasonic nebulization for disinfecting dental impressions.

    Science.gov (United States)

    Mendonca, Marcio Jose; Rafael, Renata Santos; Camilotti, Veridiana; Menolli, Rafael Andrade; Sicoli, Eliseu Augusto; Teixeira, Nancielli; Sinhoreti, Mario Alexandre Coelho

    2013-07-01

    Disinfecting dental impressions is necessary to decrease the risk of cross-contamination in dental offices. Ultrasonic nebulization has been mentioned as a microbicidal technique that can be used to disinfect contaminated dental impressions. This study compared the microbicidal effect of 2% glutaraldehyde and 0.2% peracetic acid for the disinfection of dental impressions made with vinyl polysiloxane, using 2 disinfection methods: immersion and ultrasonic nebulization. Bactericial efficacy was examined using Staphylococcus aureus and Bacillus atrophaeus as indicators. Thirty impressions were obtained and distributed randomly in 5 groups (n = 6). Group 1 was immersed in 2% glutaraldehyde immersion for 10 minutes, Group 2 was immersed in 0.2% peracetic acid for 10 minutes, Group 3 underwent ultrasonic nebulization for 10 minutes in 2% glutaraldehyde solution, Group 4 underwent ultrasonic nebulization for 10 minutes in 0.2% peracetic acid solution, and Group 5 was a control group that received no disinfectant. Both solutions experienced a 100% reduction in microorganisms following ultrasonic nebulization, as did peracetic acid following immersion; however, immersion in glutaraldehyde demonstrated lower values of reduction in B atrophaeus group, with a statistically significant difference compared with the other experimental groups.

  14. Ultraviolet (UV) disinfection of grey water: particle size effects.

    Science.gov (United States)

    Winward, G P; Avery, L M; Stephenson, T; Jefferson, B

    2008-02-01

    The impact of water quality on the ultraviolet (UV) disinfection of grey water was investigated with reference to urban water reuse. Direct UV disinfection of grey water did not meet the stringent California State Title 22 criteria for unrestricted urban water reuse due to the presence of particulate material ranging from or = 2000 microm in size. Grey water was manipulated by settling to produce fractions of varying particle size distributions and blending was employed post-disinfection to extract particle-associated coliforms (PACs). The efficacy of UV disinfection was found to be linked to the particle size of the grey water fractions. The larger particle size fractions with a mean particle size of 262 microm and above were observed to shield more coliforms from UV light than did the smaller particles with a mean particle size below 119 microm. Up to 70% of total coliforms in the larger particle size fractions were particle-associated following a UV dose (fluence) of 260 mJ.cm(-2) and would remain undetected by standard coliform enumeration techniques. Implications for urban water reuse are discussed and recommendations made for grey water treatment to ensure removal of particle-associated indicator bacteria and pathogens prior to UV disinfection.

  15. Fresh water disinfection by pulsed low electric field

    International Nuclear Information System (INIS)

    Zheng, C; Xu, Y; Liu, Z; Yan, K

    2013-01-01

    In this paper, we describe a pulsed low electric field process for water disinfection. Electric intensity of 0.6–1.7 kV cm −1 is applied. Experiments are performed with a 1.2 L axis-cylinder reactor. A bipolar pulsed power source with pulsed width of 25 μs and frequency of 100–3000 Hz is used. Water conductivity of 3–200 μs cm −1 is investigated, which can significantly affect pulsed voltage-current waveforms and injected energy. Energy per pulse rises with increased water conductivity. The initial E. Coli density and water conductivity are two major factors influencing the disinfection. No disinfection effect is performed with deionized water of 3 μs cm −1 . When water conductivity is 25 μs cm −1 and bacteria density is 10 4 –10 6 cfu ml −1 , significant disinfection effect is observed. More than 99% of the cells can be disinfected with an energy density of less than 70 J ml −1 , while water temperature is below 30 °C.

  16. [Decontamination of dental unit waterlines using disinfectants and filters].

    Science.gov (United States)

    Monarca, S; Garusi, G; Gigola, P; Spampinato, L; Zani, C; Sapelli, P L

    2002-10-01

    Bacterial contamination of the dental unit water system can become a health problem for patients, particularly if they are immunodepressed. The present study has had the purpose of evaluating the effectiveness of methods of chemical decontamination using different disinfectants (peracetic acid, hydrogen peroxide, silver salts, chloramine T, glutaraldehyde T4) and methods of physical decontamination using synthetic membranes for the filtration of water. A preliminary removal procedure of the biofilm present in the waterline has been followed in a dental unit prepared on purpose for the research; subsequently different 2-week long maintenance procedures were applied using disinfectants injected by a pump and finally the bacterial contamination of the water flowing from the waterline was evaluated. The physical decontamination was performed using 0.22 mm membrane filters, which have been installed also in another dental unit, and the filtered water was analyzed to detect bacterial contamination. The preliminary procedure of biofilm removal succeeded obtaining germ-free water. Among the disinfectants used for the maintenance of the water quality only glutaraldehyde T4 was able to reduce the bacterial contamination under the limit suggested by the ADA. The membrane filter system was not able to purify the water, but when a disinfectant (peracetic acid) was used in the last part of the waterline good results were obtained. At present no decontamination system of dental waterline is available, and glutaraldehyde T4 seems to be the best disinfectant only if integrated with periodic biofilm removal for the maintenance of the water quality.

  17. Effectiveness of Four Disinfectants against Ebola Virus on Different Materials

    Directory of Open Access Journals (Sweden)

    Sophie Smither

    2016-07-01

    Full Text Available The West Africa Ebola virus (EBOV outbreak has highlighted the need for effective disinfectants capable of reducing viral load in a range of sample types, equipment and settings. Although chlorine-based products are widely used, they can also be damaging to equipment or apparatus that needs continuous use such as aircraft use for transportation of infected people. Two aircraft cleaning solutions were assessed alongside two common laboratory disinfectants in a contact kill assay with EBOV on two aircraft relevant materials representative of a porous and non-porous surface. A decimal log reduction of viral titre of 4 is required for a disinfectant to be deemed effective and two of the disinfectants fulfilled this criteria under the conditions tested. One product, Ardrox 6092, was found to perform similarly to sodium hypochlorite, but as it does not have the corrosive properties of sodium hypochlorite, it could be an alternative disinfectant solution to be used for decontamination of EBOV on sensitive apparatus.

  18. UV disinfection for reuse applications in North America.

    Science.gov (United States)

    Sakamoto, G; Schwartzel, D; Tomowich, D

    2001-01-01

    In an effort to conserve and protect limited water resources, the States of Florida and California have actively promoted wastewater reclamation and have implemented comprehensive regulations covering a range of reuse applications. Florida has a semi-tropical climate with heavy summer rains that are lost due to run off and evaporation. Much of California is arid and suffers periodic droughts, low annual rainfall and depleted ground water supplies. The high population density combined with heavy irrigation demands has depleted ground water supplies resulting in salt-water intrusion. During the past decade, Florida reuse sites have increased dramatically from 118 to 444 plants representing a total flow capacity of 826 MGD. California presently has over 250 plants producing 1 BGD with a projected increase of 160 sites over the next 20 years. To prevent the transmission of waterborne diseases, disinfection of reclaimed water is controlled by stringent regulations. Many states regulate wastewater treatment processes, nutrient removal, final effluent quality and disinfection criteria based upon the specific reuse application. As a rule, the resulting effluents have low turbidity and suspended solids. For such effluents, UV technology can economically achieve the most stringent disinfection targets that are required by the States of California and Florida for restricted and unrestricted reuse. This paper compares UV disinfection for wastewater reuse sites in California and Florida and discusses the effect of effluent quality on UV disinfection.

  19. Cleaning, disinfection and sterilization of surface prion contamination.

    Science.gov (United States)

    McDonnell, G; Dehen, C; Perrin, A; Thomas, V; Igel-Egalon, A; Burke, P A; Deslys, J P; Comoy, E

    2013-12-01

    Prion contamination is a risk during device reprocessing, being difficult to remove and inactivate. Little is known of the combined effects of cleaning, disinfection and sterilization during a typical reprocessing cycle in clinical practice. To investigate the combination of cleaning, disinfection and/or sterilization on reducing the risk of surface prion contamination. In vivo test methods were used to study the impact of cleaning alone and cleaning combined with thermal disinfection and high- or low-temperature sterilization processes. A standardized test method, based on contamination of stainless steel wires with high titres of scrapie-infected brain homogenates, was used to determine infectivity reduction. Traditional chemical methods of surface decontamination against prions were confirmed to be effective, but extended steam sterilization was more variable. Steam sterilization alone reduced the risk of prion contamination under normal or extended exposure conditions, but did show significant variation. Thermal disinfection had no impact in these studies. Cleaning with certain defined formulations in combination with steam sterilization can be an effective prion decontamination process, in particular with alkaline formulations. Low-temperature, gaseous hydrogen peroxide sterilization was also confirmed to reduce infectivity in the presence and absence of cleaning. Prion decontamination is affected by the full reprocessing cycle used on contaminated surfaces. The correct use of defined cleaning, disinfection and sterilization methods as tested in this report in the scrapie infectivity assay can provide a standard precaution against prion contamination. Copyright © 2013 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

  20. Evaluation of 5 Cleaning and Disinfection Methods for Nets Used to Collect Zebrafish (Danio rerio)

    OpenAIRE

    Collymore, Chereen; Porelli, Gina; Lieggi, Christine; Lipman, Neil S

    2014-01-01

    Few standardized methods of cleaning and disinfecting equipment in zebrafish facilities have been published, even though the effectiveness of these procedures is vital to preventing the transmission of pathogenic organisms. Four chemical disinfectants and rinsing with municipal tap water were evaluated for their ability to disinfect nets used to capture zebrafish. The disinfectants included benzalkonium chloride+methylene blue, sodium hypochlorite, chlorine dioxide, and potassium peroxymonosu...

  1. Effect of alginate chemical disinfection on bacterial count over gypsum cast

    OpenAIRE

    Haralur, Satheesh B.; Al-Dowah, Omir S.; Gana, Naif S.; Al-Hytham, Abdullah

    2012-01-01

    PURPOSE To evaluate the efficacy of sodium hypochlorite (1 : 10) and iodophor disinfectants on alginate impressions along with their effect on the survived bacterium count on the gypsum cast. MATERIALS AND METHODS Four alginate impression on each dentate patients were made, of which Group I were not washed or disinfected, Group II impressions were merely washed with water, Group III were disinfected by spraying with sodium hypochlorite (1 : 10), Group IV were disinfected with iodophor (1 : 21...

  2. Conventional and Alternative Disinfection Methods of Legionella in Water Distribution Systems – Review

    Directory of Open Access Journals (Sweden)

    Pūle Daina

    2016-12-01

    Full Text Available Prevalence of Legionella in drinking water distribution systems is a widespread problem. Outbreaks of Legionella caused diseases occur despite various disinfectants are used in order to control Legionella. Conventional methods like thermal disinfection, silver/copper ionization, ultraviolet irradiation or chlorine-based disinfection have not been effective in the long term for control of biofilm bacteria. Therefore, research to develop more effective disinfection methods is still necessary.

  3. 40 CFR 141.709 - Developing the disinfection profile and benchmark.

    Science.gov (United States)

    2010-07-01

    ... Cryptosporidium Disinfection Profiling and Benchmarking Requirements § 141.709 Developing the disinfection profile...) of the water before or at the first customer and prior to each additional point of disinfectant...) before or at the first customer during peak hourly flow. (ii) Determine successive CTcalc/CT99.9 values...

  4. 9 CFR 51.8 - Disinfection of premises, conveyances, and materials.

    Science.gov (United States)

    2010-01-01

    ... facilities, conveyances, or other materials on the premises that would require such cleaning and disinfection... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Disinfection of premises, conveyances... ANIMALS DESTROYED BECAUSE OF BRUCELLOSIS Indemnity for Cattle, Bison, and Swine § 51.8 Disinfection of...

  5. 9 CFR 91.18 - Cleaning and disinfection of transport carriers for export.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Cleaning and disinfection of transport....18 Cleaning and disinfection of transport carriers for export. All fittings, utensils and equipment... port. Such disinfection of halters, ropes, and similar equipment used in handling and tying of animals...

  6. 9 CFR 77.19 - Cleaning and disinfection of premises, conveyances, and materials.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Cleaning and disinfection of premises... PRODUCTS TUBERCULOSIS Cattle and Bison § 77.19 Cleaning and disinfection of premises, conveyances, and... health officials. Cleaning and disinfection must be completed before the premises, conveyances, or...

  7. 9 CFR 53.7 - Disinfection of premises, conveyances, and materials.

    Science.gov (United States)

    2010-01-01

    ... least 7 days following such cleaning and disinfection, unless the Administrator determines that a... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Disinfection of premises, conveyances... LIVESTOCK OR POULTRY § 53.7 Disinfection of premises, conveyances, and materials. All premises, including...

  8. 9 CFR 77.41 - Cleaning and disinfection of premises, conveyances, and materials.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Cleaning and disinfection of premises... PRODUCTS TUBERCULOSIS Captive Cervids § 77.41 Cleaning and disinfection of premises, conveyances, and... health officials. Cleaning and disinfection must be completed before the premises, conveyances, or...

  9. Genotoxicity of the disinfection by-products resulting from peracetic acid- or hypochlorite-disinfected sewage wastewater.

    Science.gov (United States)

    Crebelli, R; Conti, L; Monarca, S; Feretti, D; Zerbini, I; Zani, C; Veschetti, E; Cutilli, D; Ottaviani, M

    2005-03-01

    Wastewater disinfection is routinely carried out to prevent the spread of human pathogens present in wastewater effluents. To this aim, chemical and physical treatments are applied to the effluents before their emission in water bodies. In this study, the influence of two widely used disinfectants, peracetic acid (PAA) and sodium hypochlorite (NaClO), on the formation of mutagenic by-products was investigated. Wastewater samples were collected before and after disinfection, in winter and in summer, at a pilot plant installed in a municipal wastewater-treatment plant. Samples were adsorbed using silica C18 cartridges and the concentrates were tested for mutagenicity in the Salmonella typhimurium reversion test with strains TA98 and TA100. Non-concentrated water samples were tested with two plant genotoxicity assays (the Allium cepa root anaphase aberration test and the Tradescantia/micronucleus test). Mutagenicity assays in bacteria and in Tradescantia showed borderline mutagenicity in some of the wastewater samples, independent of the disinfection procedure applied. Negative results were obtained in the A. cepa anaphase aberration test. These results indicate that, in the conditions applied, wastewater disinfection with PAA and NaClO does not lead to the formation of significant amounts of genotoxic by-products.

  10. Application of neutral electrolyzed water to disinfection of alginate impression.

    Science.gov (United States)

    Nagamatsu, Yuki; Chen, Ker-Kong; Nagamatsu, Hiroshi; Kozono, Yoshio; Shimizu, Hiroshi

    2016-01-01

    Neutral electrolyzed water was developed with new concepts of long-term good durability and minimum corrosiveness to metal in addition to its excellent bactericidal activities similar to acid type of electrolyzed waters. The present study examined the bactericidal effects of the neutral electrolyzed water on disinfection of the alginate impression of a dental arch model contaminated by bacteria. Only 1-min immersion in neutral electrolyzed water could sufficiently disinfect the alginate impression including the metallic tray under ultrasonic with no significant differences from acid electrolyzed waters. No bactericidal effects were found in any electrolyzed water when used as mixing water. Considering the advantages and disadvantages of each electrolyzed water in a comprehensive way, it was suggested that neutral electrolyzed water may be the most appropriate for the disinfection of alginate impression.

  11. Drinking water and biofilm disinfection by Fenton-like reaction.

    Science.gov (United States)

    Gosselin, F; Madeira, L M; Juhna, T; Block, J C

    2013-10-01

    A Fenton-like disinfection process was conducted with Fenton's reagent (H2O2) at pH 3 or 5 on autochthonous drinking water biofilms grown on corroded or non-corroded pipe material. The biofilm disinfection by Fenton-like oxidation was limited by the low content of iron and copper in the biomass grown on non-corroded plumbing. It was slightly improved by spiking the distribution system with some additional iron source (soluble iron II or ferrihydrite particles appeared as interesting candidates). However successful in situ disinfection of biofilms was only achieved in fully corroded cast iron pipes using H2O2 and adjusting the pH to 5. These new results provide additional support for the use of Fenton's processes for cleaning drinking water distribution systems contaminated with biological agents or organics. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. Disinfection of bacteria attached to granular activated carbon.

    Science.gov (United States)

    LeChevallier, M W; Hassenauer, T S; Camper, A K; McFeters, G A

    1984-01-01

    Heterotrophic plate count bacteria, coliform organisms, and pathogenic microorganisms attached to granular activated carbon particles were examined for their susceptibility to chlorine disinfection. When these bacteria were grown on carbon particles and then disinfected with 2.0 mg of chlorine per liter (1.4 to 1.6 mg of free chlorine residual per liter after 1 h) for 1 h, no significant decrease in viable counts was observed. Washed cells attached to the surface of granular activated carbon particles showed similar resistance to chlorine, but a progressive increase in sublethal injury was found. Observations made by scanning electron microscope indicated that granular activated carbon was colonized by bacteria which grow in cracks and crevices and are coated by an extracellular slime layer. These data suggest a possible mechanism by which treatment and disinfection barriers can be penetrated and pathogenic bacteria may enter drinking water supplies. Images PMID:6508306

  13. Solar water disinfecting system using compound parabolic concentrating collector

    Energy Technology Data Exchange (ETDEWEB)

    El-Ghetany, H.H.; Saitoh, T.S. [Tohoku Univ., Sendai (Japan)

    2000-05-31

    Solar water disinfection is an alternative technology using solar radiation and thermal treatment to inactivate and destroy pathogenic microorganisms present in water. The Compound Parabolic Concentrating, (CPC) collector can be used as an efficient key component for solar disinfectanting system. Two types of the CPC collectors are studied, namely the transparent-tube and the Copper-tube CPC collector. It is found that after 30 minutes of exposing the water sample to solar radiation or heating it up to 65 degree C for a few minuets all the coliform bacterial present in the contaminated water sample were completely eliminated. In this article, the effect of water temperature on the disinfecting process was presented. Thermal and micro-biological measurements were also made to evaluate the system performance. (author)

  14. Disinfection procedures for in vitro propagation of Anthurium

    Directory of Open Access Journals (Sweden)

    Silva Jaime A. Teixeira da

    2015-06-01

    Full Text Available Disinfection of plant material is the most important step of the tissue culture protocol. In this process, an attempt is made to eliminate microbial contaminants from the surface and interior of plant material, thus giving the explant a fighting chance at survival in vitro. Initial cultures of Anthurium species and cultivars, which are usually established from ex vitro material grown in a greenhouse, pots or in the field, easily contaminate the in vitro milieu. This review highlights the differences in disinfection protocols that exist for different species or cultivars of Anthurium. The protocol needs to be adjusted based on the material used: spadices, spathes, seeds, leaves, or roots. Regrettably, most of the currently published protocols, derived from a literature that spans over 100 published papers, have numerous weaknesses and flaws in the information provided pertaining to disinfection and infection levels. Advice for future Anthurium researchers should thus be followed cautiously.

  15. Biophysical methods for disinfection and stimulation of wheat seeds

    International Nuclear Information System (INIS)

    Marinkovic, S.; Marinkovic, B.

    2007-01-01

    In this paper we are shown results of applying electron treatment (disinfection of seed by electrons), and RIES method (electromagnetic seed stimulation). Four cultivars of wheat were used in this trial: Renesansa, Durumko, NS-Rana 5 and Sonata. Seed was treated with fast electrons and just before sowing stimulated by ultra low frequency electromagnetic field (from 0 to 100 Hz). For seed disinfection was used chemical treatment as well, as control variant. Control variant for all treatments was seed without any disinfection. The highest number of spikelets per spike was obtained at variant H+RIES. The highest spike length was obtained at variants e sup(-) + RIES and control. At variant H+RIES was achieved the highest grain number. Treatment H had influence on decreasing of grain mass per spike in relation to control variant, for significant value of 0.15 g. The highest grain mass per spike was obtained at variant e sup(-) + RIES

  16. A novel cupping-assisted plasma treatment for skin disinfection

    Science.gov (United States)

    Xiong, Zilan; Graves, David B.

    2017-02-01

    A novel plasma treatment method/plasma source called cupping-assisted plasma treatment/source for skin disinfection is introduced. The idea combines ancient Chinese ‘cupping’ technology with plasma sources to generate active plasma inside an isolated, pressure-controlled chamber attached to the skin. Advantages of lower pressure include reducing the threshold voltage for plasma ignition and improving the spatial uniformity of the plasma treatment. In addition, with reduced pressure inside the cup, skin pore permeability might be increased and it improves attachment of the plasma device to the skin. Moreover, at a given pressure, plasma-generated active species are restricted inside the cup, raising local reactive species concentration and enhancing the measured surface disinfection rate. A surface micro-discharge (SMD) device is used as an example of a working plasma source. We report discharge characteristics and disinfection efficiency as a function of pressure and applied voltage.

  17. [Disinfectants for the skin of premature].

    Science.gov (United States)

    Cucurachi, G; Tuoto, M G

    2010-06-01

    Nosocomial infections are among the leading causes of mortality and morbidity in neonatal intensive care units. Prevention of healthcare-associated infections is based on strategies that aim to limit susceptibility to infections by enhancing host defences, interrupting trasmission of organisms by healthcare workers and by promoting the judicious use of antimicrobials. Strategies for the prevention of nosocomial infections include hand hygiene practices, prevention of central venous (cvc)-related bloodstream infections, judicious use of antimicrobials for therapy, enhancement of host defences, skin care and early enteral feeding with human milk. Major concerns about the use of alcoholic chlorhexidine are for the high risk of skin burns in extremely premature infants during the first days of life, when the skin is thin and not fully keratinesed. Aqueous chlorhexidine could be less irritant when used in very low birthweigth infants and thus could represent a good option. A recent prospective trial of adult patients showed similar effectiveness of alcoholic and aqueos solutions of chlorexidine. However, to date no study evaluated whether the aqueos formulation is less harmful and as effective as the alcoholic formulation in neonatal infants. The lack of evidence for neonatal patients prompts urgent need for large randomised controlled trials comparing effectiveness and safety of different skin disinfectants before CVC placement in neonates and particulary in very low birth-weight infants. Nosocomial infections are still of the most serious problems for the neonatal intensive care unit. Therefore every effort must be implemented to reduce the incidence of these infections, can not be considered a toll required hospitalization, as it may not be acceptable for a place of shelter and care as the hospital may itself be a source of disease.

  18. Generation of ozone foam and its application for disinfection

    Science.gov (United States)

    Hiragaki, Keisuke; Ishimaru, Tomiya; Nakanishi, Masaru; Muraki, Ryouji; Nieda, Masanori; Yamabe, Chobei

    2015-07-01

    Generated ozone foam was applied to the disinfection of Pseudomonas fluorescens. The effect of disinfection has been confirmed experimentally and new equipment for the disinfection of hands using this ozone foam has been put on the market for the practical use. The ozone foam was produced in the foam generator after mixing the water including surfactant (30 mL/min) and air including ozone (1000 ppm = 2.14 g/m3 ~ 1600 ppm = 3.4 g/m3, 300 mL/min). The liquid-to-gas ratio is 100 L/m3. The concentration of dissolved ozone in the thin liquid films of the bubbles was about 3 mg/L which was measured by the chemical method of the KI absorption and titration of sodium thiosulfate solution. The disinfection test samples were prepared using the PET disk on which Pseudomonas fluorescens of its number of more than 108 were attached. Test sample was inserted into ozone foam set on the glass plate for one to 6 min. The survival rate log (N/N0 decreased with time and its value of about-2.6 (i.e., ~1/400) was obtained at 6 min (2 min × 3 times repeated). It was also confirmed that the ozone foam was useful for the disinfection of hands. For more effective disinfection (in case of taking a long time for foam melting), the ozone foam was broken by force and changed into ozone water by which the survival rate decreased ×4 (i.e., N/N0 = 1/10 000) at 4 ~ 6 min. Contribution to the topical issue "The 14th International Symposium on High Pressure Low Temperature Plasma Chemistry (HAKONE XIV)", edited by Nicolas Gherardi, Ronny Brandenburg and Lars Stollenwark

  19. Effect of new disinfectant substances on pseudomonas aeruginosa

    International Nuclear Information System (INIS)

    Majtan, V.

    1998-01-01

    The anti-bacterial effect of 13 new commercially manufactured disinfectant substances on P. aeruginosa strain was studied. The substances tested represent 9 quaternary ammonium salts QAT and 4 combined QAT with other ingredients. The antimicrobial efficacy was characterised by influencing the growth and reproduction of bacterial cells expressed either by MIC and ED 50 as well as and ED 50 , as well as by the inhibition of incorporation rate of incorporation rate of [ 14 C] adenine and [ 14 C] leucine. The method of inhibition of [ 14 C] precursors is suitable as one from possible evaluation criterion on anti-bacterial efficacy of synthetic disinfectant substances. (authors)

  20. [Control of disinfection in the buildings of pig farms].

    Science.gov (United States)

    Maris, P

    1990-01-01

    A survey carried out in pig farms was undertaken in order to compare 4 disinfectants used in 13 disinfecting operations, during the vacation period. It was immediately noticeable that after swabbing and counting the staphylococci, the chloramine T-based preparation was more effective than the quaternary ammonium-aldehyde association, phenolic acid derivatives or the quaternary ammonium preparations. We then observed that although the number of organisms decreased by 99.8%, their number on slatted floors still ranged between 0.02 x 10(4) and 3 x 10(4) per cm2.

  1. Monitoring and improving the effectiveness of surface cleaning and disinfection.

    Science.gov (United States)

    Rutala, William A; Weber, David J

    2016-05-02

    Disinfection of noncritical environmental surfaces and equipment is an essential component of an infection prevention program. Noncritical environmental surfaces and noncritical medical equipment surfaces may become contaminated with infectious agents and may contribute to cross-transmission by acquisition of transient hand carriage by health care personnel. Disinfection should render surfaces and equipment free of pathogens in sufficient numbers to prevent human disease (ie, hygienically clean). Copyright © 2016 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

  2. [Experiments on disinfection of vaccinia virus embedded in scabs and/or at the hand].

    Science.gov (United States)

    Schümann, K; Grossgebauer, K

    1977-01-01

    Vaccinia viruses embedded in rabbit dermal scabs were subjected to physical and chemical disinfection procedures. Scabs were suspended in vitro without saline or in physiological saline, and left for 1 hour at 70 to 90 degrees C. A complete inactivation was achived only in those scab samples which had been incubated at 90 degrees C for 1 hour and suspended in physiological saline. Scabs which had been placed in a disinfecting apparatus (Vacudes 4000) filled with mattrasses consistently proved to be free of infectious vaccinia viruses in each of the chosen programs. In addition scabs were subjected to disinfection by means of chemical disinfecting agents. The scabs had been placed in a chemical disinfecting suspension and left there for 90 minutes. Complete disinfection was obtained with glutaraldehyde 2%, formaldehyde 2%, Lysoformin 2% or 3%, phenol 5% and chloramine T 2%. Complete disinfection was likewise achieved after 3 hours treatment with some alchohols (ethylalcohol 80%, isopropylalcohol 7%, n-propylalcohol 60%), Amocid 5% and formaldehyde 1%.0.5% formaldehyde caused complete disinfection when applied for 6 hours. The only exception was a Quat which did not disinfect fully even after 18 hours application. Concerning the tests to disinfect the hands complete disinfection occurs when using chloramine T (1.5%) or isopropylalcohol (70%) in 2 to 5 minutes. Further tests were performed with scabs which were placed in sick rooms that were terminally disinfected with formaline vapor. It could be confirmed that the usual terminal disinfection with formaldehyde vapor was unable to completely disinfect the scabs. It is necessary to double the amount of formaldehyde (10 g formaldehyde per cubic metre of space) and prolong the period of treatment to 24 hours to achieve a greater degree of disinfection rate.

  3. Application of a high-level peracetic acid disinfection protocol to re-process antibiotic disinfected skin allografts.

    Science.gov (United States)

    Lomas, R J; Huang, Q; Pegg, D E; Kearney, J N

    2004-01-01

    Skin allografts, derived from cadaveric donors, are widely used for the treatment of burns and ulcers. Prior to use in clinical situations, these allografts are disinfected using a cocktail of antibiotics and then cryopreserved. Unfortunately, this antibiotic disinfection procedure fails to decontaminate a significant proportion and these contaminated grafts can not be used clinically. We have investigated whether it is possible to apply a second, more potent disinfection procedure to these contaminated grafts and effectively to re-process them for clinical use. Cadaveric skin grafts, treated with antibiotics and cryopreserved, were thawed and a peracetic acid (PAA) disinfection protocol applied. The grafts were then preserved in a high concentration of glycerol or propylene glycol, and properties thought to be essential for successful clinical performance assessed. The cytotoxicity of the grafts was assessed using both extract and contact assays; damage to the skin collagen was assessed using a collagenase susceptibility assay and the capacity of the grafts to elicit an inflammatory response in vitro was assessed by quantifying the production of the pro-inflammatory cytokine TNF-alpha by human peripheral blood mononuclear phagocytes. PAA disinfection, in conjunction with either glycerol or propylene glycol preservation, did not render the grafts cytotoxic, pro-inflammatory, or increase their susceptibility to collagenase digestion. The rates of penetration of glycerol and propylene glycol into the re-processed skin were comparable to those of fresh skin. This study has demonstrated that PAA disinfection combined with immersion in high concentrations of either glycerol or propylene glycol was an effective method for re-processing contaminated skin allografts, and may justify their clinical use.

  4. Disinfection ultraviolet radiation bulk food products

    OpenAIRE

    Семенов, А. А.

    2014-01-01

    В работе представлены результаты обеззараживания сыпучих пищевых продуктов ультрафиолетовым излучением. Предложена технология бактерицидного обеззараживания сыпучих продуктов с размером частиц до 50 мкм. Проведены необходимые расчеты, связанные с дозой облучения, с временем пребывания частиц в зоне облучения и необходимой дозой инактивации в зависимости от вида бактерий. Considered the results of bulk food products disinfection by ultraviolet radiation. The technology bactericidal disinfec...

  5. Does disinfection of environmental surfaces influence nosocomial infection rates? A systematic review.

    Science.gov (United States)

    Dettenkofer, Markus; Wenzler, Sibylle; Amthor, Susanne; Antes, Gerd; Motschall, Edith; Daschner, Franz D

    2004-04-01

    To review the evidence on the effects of disinfection of environmental surfaces in hospitals (as compared with cleaning without use of disinfectants) on the occurrence of nosocomial infections. Systematic review of experimental and nonexperimental intervention studies dealing with environmental disinfection or cleaning in different health care settings. A total of 236 scientific articles were identified. None described a meta-analysis, systematic review, or randomized controlled trial. Only 4 articles described completed cohort studies matching the inclusion criteria. None of these studies showed lower infection rates associated with routine disinfection of surfaces (mainly floors) versus cleaning with detergent only. Disinfectants may pose a danger to staff, patients, and the environment and require special safety precautions. However, targeted disinfection of certain environmental surfaces is in certain instances an established component of hospital infection control. Given the complex, multifactorial nature of nosocomial infections, well-designed studies that systematically investigate the role of surface disinfection are required.

  6. One plunge or two?--hand disinfection with alcohol gel.

    Science.gov (United States)

    Macdonald, Duncan J M; Mckillop, Elisabeth C A; Trotter, Sylvia; Gray, Alastair J R

    2006-04-01

    To compare health care workers' hand surface coverage using two different volumes of alcohol gel for hand disinfection. and methods. A total of 84 members of staff in our hospital were studied. Subjects were asked to disinfect their hands with alcohol gel containing a clear fluorescent substance. Performance was assessed by using UV light to identify areas which had been missed, and the total surface area missed was calculated. A total of 42 subjects received 3.5 ml of alcohol gel, and 42 age-, sex-, and job-matched subjects received 1.75 ml of alcohol gel. Significantly less area was missed when hand disinfecting with double the volume of alcohol gel; 1.23 versus 6.35% surface area was missed (P disinfection significantly improves the efficiency of coverage of the hands with alcohol gel. This may result in lower bacterial count on the hands and may reduce the spread of nosocomial infections including that of methicillin-resistant Staphylococcus aureus.

  7. Surface dielectric barrier discharge jet for skin disinfection

    NARCIS (Netherlands)

    Creyghton, Y.; Meijer, R.; Verweij, P.; Zanden, F. van der; Leenders, P.

    2012-01-01

    A consortium consisting of the research institute TNO, the medical -university and hospital St Radboud and two industrial enterprises is working on a non-thermal plasma treatment method for hand disinfection. The group is seeking for cooperation, in particular in the field of validation methods and

  8. Control of house-dust mites with home disinfectants

    NARCIS (Netherlands)

    Schober, G.; Wetter, G.; Bischoff, E.; Bronswijk, van J.E.M.H.; Kniest, F.M.

    1987-01-01

    Chemical disinfectants and biocidal preparations used in households were tested in the laboratory for their ability to kill the house-dust miteDermatophagoides farinae. Batches of ten specimens were soaked in aqueous solutions or suspensions containing 0.0, 0.1, 0.3, 1.0, 3.0 and 10.0% (by volume)

  9. 9 CFR 53.6 - Disinfection of animals.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Disinfection of animals. 53.6 Section 53.6 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF... of animals. Animals of species not susceptible to the disease for which a quarantine has been...

  10. A parametrical study of disinfection with hydrodynamic cavitation.

    Science.gov (United States)

    Arrojo, S; Benito, Y; Tarifa, A Martínez

    2008-07-01

    The physical and chemical conditions generated by cavitation bubbles can be used to destroy microorganisms and disinfect wastewater. The effect of different cavitation chamber designs and diverse operational parameters on the inactivation rate of Escherichia coli have been studied and used to understand the mechanisms involved in cell disruption.

  11. Disinfection Alternatives for Small Communities in Puerto Rico

    Science.gov (United States)

    Disinfection Alternatives for Small Communities in Puerto Rico Craig Patterson1, Graciela Ramirez Toro2, Harvey Minnigh2, Cristina Maldonado3, and Rajib Sinha4 1U.S. EPA Office of Research and Development, 2Centro de Educación, Conservación e Interpretación Ambiental (CECIA),...

  12. A biocoagulant slow sand filtration for disinfection of Toxoplasma ...

    African Journals Online (AJOL)

    An integrated low-tech biocoagulant-sand filter drum for disinfection of oocysts of Toxoplasma gondii targeted for developing countries was evaluated. Dirty and turbid water (130.3 NTU) from Mezam River and leachates from dump sites and stagnant water in Bamenda, Cameroon, was analyzed microscopically after ...

  13. Assessment of peracetic acid disinfected effluents by microbiotests.

    Science.gov (United States)

    Antonelli, M; Mezzanotte, V; Panouillères, M

    2009-09-01

    Bioassays were performed by commercially available kits on peracetic acid (PAA) solutions, at different concentrations, and on secondary effluents (from two different wastewater treatment plants) after disinfection at bench-scale, considering both samples containing residual active PAA and the same samples where residual PAA was quenched. Four indicator organisms were used: Vibrio fischeri, Thamnocephalus platyurus, Daphnia magna, and Selenastrum capricornutum. The experiments lead to conclude that Thamnocephalus platyurus is a very sensitive organism, probably not adequate to perform a reliable toxicity assessment of effluents for monitoring purposes. The presence of specific organic compounds deriving from human metabolism and urban pollution, even at very low concentrations, can affect the results of bioassays, especially those performed on Vibrio fischeri. PAA is toxic for bacteria and crustaceans even at concentrations lower than the ones commonly used in wastewater disinfection (2-5 mg/L), while its effect on algae is smaller. The toxic effect on bacteria was expected, as PAA is used for disinfection, but its possible influence on biological processes in the receiving aquatic environment should be considered. Toxicity on crustaceans would confirm the fact that discharging disinfected effluents could raise some environmental problems.

  14. Wastewater disinfection alternatives: chlorine, ozone, peracetic acid, and UV light.

    Science.gov (United States)

    Mezzanotte, V; Antonelli, M; Citterio, S; Nurizzo, C

    2007-11-01

    Disinfection tests were carried out at pilot scale to compare the disinfection efficiency of ozone, sodium hypochlorite (NaOCl), peracetic acid (PAA), and UV irradiation. Total coliforms, fecal coliforms, and Escherichia coli were monitored as reference microorganisms. Total heterotrophic bacteria (THB) were also enumerated by cytometry. At similar doses, NaOCl was more effective than PAA, and its action was less affected by contact time. The results obtained by ozonation were comparable for total coliforms, fecal coliforms, and E. coli. On the contrary, some differences among the three indicators were observed for NaOCl, PAA, and UV. Differences increased with increasing values of the disinfectant concentration times contact time (C x t) and were probably the result of different initial counts, as total coliforms include fecal coliforms, which include E. coli. The UV irradiation lead to complete E. coli removals, even at low doses (10 to 20 mJ/cm2). Total heterotrophic bacteria appeared to be too wide a group to be a good disinfection indicator; no correlation was found among THB inactivation, dose, and contact time.

  15. 7 CFR 301.89-12 - Cleaning, disinfection, and disposal.

    Science.gov (United States)

    2010-01-01

    ... indica must be cleaned and disinfected in accordance with § 301.89-13 prior to being used in the conditioning of seed that has tested negative for the spores of Tilletia indica or to being moved from a... move bunted-kernel-positive host crops, including trucks, railroad cars, and other containers, that...

  16. A prototype catheter designed for ultraviolet C disinfection

    DEFF Research Database (Denmark)

    Bak, Jimmy; Begovic, Tanja

    2013-01-01

    UVC light exposure, sampling and plate counting. Findings Two minutes of UVC exposure was sufficient to obtain 4 log10 disinfection for the full-length prototype catheter. This exposure corresponds to ∼40 mJ/cm2 at the catheter tip and indicates that even shorter exposure times can be achieved...

  17. The Effect of Various Brands of Chloroxylenol disinfectants on Some ...

    African Journals Online (AJOL)

    Suspension and surface viability tests were carried out to determine the effects of various brands of chloroxylenol disinfectants on clinically important nosocomial gram negative and gram-positive organisms. Dettol and morigard brands of chloroxylenol inhibited gram-positive organisms at a dilution of 1 in 50. Tiscol brand of ...

  18. UASB reactor effluent disinfection by ozone and chlorine

    NARCIS (Netherlands)

    Ribeiro da Silvia, G.H.; Bruning, H.; Gerrity, D.; Daniel, L.A.

    2015-01-01

    This research studied the sequential ozone and chlorine process with respect to, the inactivation of indicator bacteria and the formation of ozone disinfection byproducts in sanitary wastewater effluent. The applied ozone doses were 5, 8 and 10 mg.O3.L-1, followed by chlorine doses of 10, 20 and 30

  19. A practical evaluation of detergent and disinfectant solutions on ...

    African Journals Online (AJOL)

    Student01

    2012-01-06

    Jan 6, 2012 ... inactivation efficacy and effect on material corrosion ... Cleaning and disinfection agents were evaluated against selected bacteria on ... bacteria strains: Escherichia coli K12, E. coli DSM 682, Salmonella ... in terms of the lifespan of the equipment, and also ..... Individual descriptions of the observed basis.

  20. The effect of various disinfectants on dental shade guides.

    Science.gov (United States)

    Huang, Peterson Y; Masri, Radi; Romberg, Elaine; Driscoll, Carl F

    2014-09-01

    Dental shade guides are used to evaluate tooth color before prosthodontic procedures and are subjected to disinfection after use. The effect of disinfection on shade guides has not been thoroughly investigated. The purpose of this study was to evaluate the effect of disinfectants on the color of shade tabs. Changes in the color (ΔE) of VITA Classical Shade Guide tabs were measured with a VITA Easyshade spectrophotometer in the CIELAB system and calculated after being subjected to Cavicide, Asepticare TB, Sporicidin, and distilled water (control) over a simulated period of 2 years. Statistical analysis was accomplished by a 2-way analysis of variance followed by the Tukey honestly significant difference (HSD) test (α=.05). A significant difference was noted in the degree of shade tab color change, depending on the type of disinfectant used (F=153.2, PCavicide (ΔE=1.198). The average total CIELAB color difference for 50% human perceptibility is approximately 1 unit (under standardized laboratory conditions). In the oral cavity, however, an average change of 3.7 ΔE units could still allow teeth to be perceived as having the same color. Therefore, although the results are statistically significant, they may not be clinically important. Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  1. [The effect of disinfectant soaking on dental gypsum model size].

    Science.gov (United States)

    Zhu, Cao-yun; Xu, Yun-wen; Xu, Kan

    2012-12-01

    To study the influence of disinfectant soaking on the dimensional stability of three kinds of dental gypsum model. Three commonly used gypsums ( type III,IV,Vtype) in clinic were used to make 24 specimens for 50 mm×15 mm×10 mm in size. One hour after release, the specimens were placed for 24 h. A digital caliper was used to measure the size of the gypsum model. Distilled water immersion was as used control, glutaraldehyde disinfectant and Metrix CaviCide disinfectant soaking were used for the experimental group. After soaking for 0.5h, the gypsum models were removed and placed for 0.5 h, 1 h, 2 h, 24 h. The size of the models was measured again using the same method. The data was analyzed with SPSS10.0 software package. The initial gypsum model length was (50.07±0.017) mm, (50.048±0.015) mm and (50.027±0.015) mm. After soaking for different times, the size of the model changed little, and the dimensions changed less than 0.01%. The results show that disinfectant soaking has no significant effect on dental model dimensions.

  2. Effects of Ozone and Photo‑Activated Disinfection against ...

    African Journals Online (AJOL)

    Objectives: The purpose of this study was to compare the antibacterial effects of gaseous ozone (O3) and photo‑activated disinfection (PAD) methods against Enterococcus faecalis (E. faecalis) biofilms. Materials and Methods: Sixty‑five human mandibular premolars with straight root canals were selected. After root canal ...

  3. Moist Heat Disinfection and Revisiting the A0 Concept.

    Science.gov (United States)

    McCormick, Patrick J; Schoene, Michael J; Dehmler, Matthew A; McDonnell, Gerald

    2016-04-02

    Moist heat is employed in the medical device, pharmaceutical, and food processing industries to render products and goods safe for use and human consumption. Applications include its use to pasteurize a broad range of foods and beverages, the control of microbial contamination of blood products, and treatment of bone tissue transplants and vaccines. In the pharmaceutical industry, water heated to 65°C to 80°C is used to sanitize high-purity water systems. In healthcare, it has been employed for decades to disinfect patient care items ranging from bedpans to anesthesia equipment. There is a good understanding of the conditions necessary to achieve disinfection of microorganisms at temperatures ranging from 65°C to 100°C. Based on this information, the efficacy of moist heat processes at a range of exposure times and temperatures can be quantified based on mathematical models such as the A0 calculation. While the A0 concept is recognized within the European healthcare community, it has yet to be widely adopted within the United States. This article provides information regarding the A0 concept, a brief overview of the classification of thermal disinfection for use with healthcare applications within the United States, and recent data on reinvestigating the thermal disinfection of a selected panel of microorganisms and a mixed culture biofilm.

  4. Disinfection Pilot Trial for Little Miami WWTP | Science ...

    Science.gov (United States)

    There is a serious interest growing nationally towards the use of PAA at various stages of public waste water treatment facilities; one of such use is secondary waste water treatment. MSDGC is currently interested in improving efficiency and economic aspects of waste water treatment. MSDGC requested for ORD’s support to evaluate alternative cost-effective disinfectants. This report herein is based on the data generated from the field pilot test conducted at the Little Miami Wastewater Treatment Plant. Chlorine assisted disinfection of wastewaters created the concern regarding the formation of high levels of toxic halogenated disinfection byproducts (DBPs) detrimental to aquatic life and public health. Peracetic acid is emerging as a green alternative to chlorine and claimed to have economic and social benefits. In addition, it is a relatively simple retrofit to the existing chlorine treated wastewater treatment facilities. PAA is appealed to possess a much lower aquatic toxicity profile than chlorine and decays rapidly in the environment, even if overdosed. As a result, PAA generally does not need a quenching step, such as dechlorination, reducing process complexity, sodium pollution and cost. PAA treatment does not result in the formation of chlorinated disinfection by-products such as trihalomethanes (THMs), haloacetic acids and other byproducts such as cyanide and n-Nitrosodimethylamine (NDMA).

  5. Disinfection of wastewater with peracetic acid: a review.

    Science.gov (United States)

    Kitis, Mehmet

    2004-03-01

    Peracetic acid is a strong disinfectant with a wide spectrum of antimicrobial activity. Due to its bactericidal, virucidal, fungicidal, and sporicidal effectiveness as demonstrated in various industries, the use of peracetic acid as a disinfectant for wastewater effluents has been drawing more attention in recent years. The desirable attributes of peracetic acid for wastewater disinfection are the ease of implementing treatment (without the need for expensive capital investment), broad spectrum of activity even in the presence of heterogeneous organic matter, absence of persistent toxic or mutagenic residuals or by-products, no quenching requirement (i.e., no dechlorination), small dependence on pH, short contact time, and effectiveness for primary and secondary effluents. Major disadvantages associated with peracetic acid disinfection are the increases of organic content in the effluent due to acetic acid (AA) and thus in the potential microbial regrowth (acetic acid is already present in the mixture and is also formed after peracetic acid decomposition). Another drawback to the use of peracetic acid is its high cost, which is partly due to limited production capacity worldwide. However, if the demand for peracetic acid increases, especially from the wastewater industry, the future mass production capacity might also be increased, thus lowering the cost. In such a case, in addition to having environmental advantages, peracetic acid may also become cost-competitive with chlorine.

  6. [The principle of registration, evaluation and testing of disinfecting preparations].

    Science.gov (United States)

    Röhm-Rodowald, Ewa; Jakimiak, Bozenna; Podgórska, Marta

    2008-01-01

    Disinfectants are used to produce a state in which the number of living micro-organisms has been reduced to a level which is appropriate to the practical situation. For any products which are included in the Biocidal Directive 98/8/EC, for which specific activity is claimed, test data has to be approved by the regulatory authority and a product license obtained before the product can be offered for sale. Disinfectants can be recorded as biocidal products or medical devices. Presently, it is possible to measure the activity of a product on defined micro-organisms in specified experimental conditions. Efficacy is the result of the use of a product according to a defined application. To allow different requirements in different areas of application, separate tests and pass criteria have been or will be prepared for each of following three areas of application: medical, veterinary and group comprising food, industrial, domestic and institutional areas. The laboratory methods to be used for testing the activity of chemical disinfectants meets the European standards. The tests are categorised on a modular basis as follows: phase 1 tests, phase 2 step 1 tests, phase 2 step 2 tests and phase 3 tests. In order to claim that a product has disinfectant properties, suitable for use in the medical area, the product shall be tested according to European standards: phase 2 step 1 tests, phase 2 step 2 tests. Phase 1 tests are not required to support claims for chemical disinfectants used in human medicine. Only phase 1 tests are required to support claims for active substances for which no particular area of application is specified. Medical devices are subjects to the European Directive 93/42/EEC which requires that a product must carry a CE mark. Disinfectants which are intended specifically by its manufacturer to be used on medical devices are themselves medical devices and so these products, as well as conforming to the instrument disinfection European standards as specified

  7. Disinfecting the iPad: evaluating effective methods.

    Science.gov (United States)

    Howell, V; Thoppil, A; Mariyaselvam, M; Jones, R; Young, H; Sharma, S; Blunt, M; Young, P

    2014-06-01

    Tablet computers are increasingly used in healthcare, but they may carry nosocomial pathogens. There are few data available on how to clean an iPad effectively for use in the clinical setting. We aimed to identify the most effective method of decontaminating the Apple iPad, without causing damage, and establish the duration of any residual effect. Following contamination with a microbial broth (meticillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococcus (VRE) and Clostridium difficile), we examined efficacy of iPad disinfection in the laboratory using six different disinfectant wipes: Sani-Cloth CHG 2% (chlorhexidine 2%/alcohol 70%), Clorox, Tristel, Trigene, soap and water, and plain cloth. Following cleaning, iPads were recontaminated to examine residual activity. After 480 Sani-Cloth CHG 2% disinfecting episodes, functional and visual analysis of iPads was performed by blinded subjects. With the exception of Clostridium difficile, Sani-Cloth CHG 2% and Clorox wipes were most effective against MRSA and VRE, and they were significantly better than the Apple-recommended plain cloth (P ≤ 0.001). A substantial residual antimicrobial effect was seen for >6h after wiping the iPad with Sani-Cloth CHG 2% despite repeated recontamination and without further disinfection. The functionality or visual appearance of the iPad was not damaged by repeated use of Sani-Cloth CHG 2% wipes. Sani-Cloth CHG 2% wipes effectively disinfect the iPad against MRSA and VRE, with a residual antibacterial effect and without causing damage. Copyright © 2014 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

  8. Dimensional Stability of Color-Changing Irreversible Hydrocolloids after Disinfection

    Directory of Open Access Journals (Sweden)

    Khaledi AAR

    2015-03-01

    Full Text Available Statement of Problem: Disinfection of dental impressions is a weak point in the dental hygiene chain. In addition, dental office personnel and dental technicians are endangered by cross-contamination. Objectives: This study aimed to investigate the dimensional stability of two color-changing irreversible hydrocolloid materials (IH after disinfection with glutaraldehyde. Materials and Methods: In this in vitro study, impressions were made of a master maxillary arch containing three reference inserts on the occlucal surface of the left and right maxillary second molars and in the incisal surface of the maxillary central incisors. Two types of color-changing irreversible hydrocolloid (tetrachrom, cavex were used. Glutaraldehyde 2% was used in two methods of spraying and immersion to disinfect the impressions. The control group was not disinfected. Casts were made of type IV gypsum. The linear dimensional change of the stone casts was measured with a profile projector. For statistical analysis, Kruskall-Wallis and Mann-Witney tests were used (α=0.05. Results: By immersion method, the casts fabricated from tetrachrom were 0.36% larger in the anteroposterior (AP and 0.05% smaller in cross arch (CA dimensions; however, the casts prepared after spraying of tetrachrom were 0.44% larger in the AP and 0.10% smaller in CA dimensions. The casts made from Cavex were 0.05% smaller in the AP and 0.02% smaller in CA dimensions after spraying and 0.01% smaller in the AP and 0.003% smaller in CA dimensions after immersion. Generally there were not significant differences in AP and CA dimensions of the experimental groups compared to the control (p > 0.05. Conclusions: Disinfection of the tested color-changing irreversible hydrocolloids by glutaraldahyde 2% did not compromise the accuracy of the obtained casts.

  9. Disinfectant choices in veterinary practices, shelters and households : ABCD guidelines on safe and effective disinfection for feline environments

    NARCIS (Netherlands)

    Addie, Diane D; Boucraut-Baralon, Corine; Egberink, Herman; Frymus, Tadeusz; Gruffydd-Jones, Tim; Hartmann, Katrin; Horzinek, Marian C; Hosie, Margaret J; Lloret, Albert; Lutz, Hans; Marsilio, Fulvio; Pennisi, Maria Grazia; Radford, Alan D; Thiry, Etienne; Truyen, Uwe; Möstl, Karin

    OVERVIEW: Regardless of whether a pathogen is viral, bacterial, parasitic, fungal or an emerging unknown, the mainstay of infectious disease control is hygiene, and the cornerstone of good hygiene is effective disinfection. CHALLENGES AND CURRENT CHOICES: Certain pathogens present a challenge to

  10. Disinfection aboard cruise liners and naval units: formation of disinfection by-products using chlorine dioxide in different qualities of drinking water.

    Science.gov (United States)

    Ufermann, Petra; Petersen, Hauke; Exner, Martin

    2011-12-01

    The world-wide deployment of cruise liners and naval units has caused an increased need for the disinfection of drinking water. The main cause for this is the unknown quality of drinking water in foreign harbours--besides the formation of bio-films due to the climatically disadvantageous conditions in the operational area. Water conduits on board are currently disinfected with calcium hypochlorite in case of microbiological contamination. Chemical and physical analyses after disinfection with calcium hypochlorite have shown that organic by-products consisting of trihalomethanes develop in considerable amounts during disinfection. Furthermore, the method is susceptible to handling errors and thus often leads to insufficient disinfection results. Hitherto, the use of other disinfection methods allowed by government regulations, especially chlorine dioxide, is not widely spread. Unlike disinfection with calcium hypochlorite, chlorine dioxide does not lead to the formation of trihalomethanes. Typical disinfection by-products (DBP) are the anions chlorite and chlorate, which are formed in oxidative processes. The formation conditions of these anions have not yet been elucidated. For this reason, the probability of the generation of inorganic by-products after disinfection with chlorine dioxide has been determined, and their occurrence in drinking water on board has been examined with respect to a possible correlation between water quality and the formation of chlorate and chlorite. Therefore, a chromatographic method was developed and validated in order to determine the periodical development of chlorate and chlorite from chorine dioxide in purified water at different pH-values as well as in actual drinking water samples from water conduits on board. The formation of the by-products chlorite and chlorate after disinfection with chlorine dioxide is influenced neither by pH-value nor by chemical properties of the disinfected water. Considering the examined conditions

  11. The Effect of Disinfection by Spray Atomization on Dimensional Accuracy of Condensation Silicone Impressions

    Directory of Open Access Journals (Sweden)

    Fariba Saleh Saber

    2010-12-01

    Full Text Available Background and aims. The condensation silicone impression materials are available, but there is little knowledge of their accuracy after disinfection. The objective of this study was to evaluate the effect of the disinfection by spray atomization on dimensional accuracy of condensation silicone impressions. Materials and methods. Impressions were made on a stainless steel master model containing a simulated two complete crown preparation with an edentulous space interposed using Spidex® and Rapid® impression materials. 44 impressions were made with each material, of which 16 were disinfected with 5.25% sodium hypochlorite, 16 were disinfected with 10% iodophor and 12 were not disinfected. Three dimensional measurements of working casts, including interpreparation distance, height, and diameter, were calculated using a measuring microscope graduated at 0.001 mm. Dimensional changes (mm between the disinfected and non-disinfected working casts were compared. One-way analysis of variance (ANOVA was employed to analyze the data (α=0.05. Results. Disinfection of each condensation silicone material by spraying atomization with two different disinfectant material resulted in significant change in interpreparation distance (p<0.05. Changes in height and diameter were only significant in Spidex® impressions (p<0.05. Conclusion. Significant changes in the mean dimensions were seen as a result of disinfection by spraying; however, the dimensional changes do not seem great enough to cause critical positional distortion of teeth when fixed partial denture restorations are made.

  12. Resistance to disinfection of a polymicrobial association contaminating the surface of elastomeric dental impressions.

    Science.gov (United States)

    Giammanco, Giovanni M; Melilli, Dario; Rallo, Antonio; Pecorella, Sonia; Mammina, Caterina; Pizzo, Giuseppe

    2009-04-01

    The aim of this study was to evaluate the ability to resist disinfection of a polymicrobial association contaminating the surface of dental impressions obtained with two different elastomers: a polyether (Impregum) and an addition-polymerized silicone (Elite). Impressions were contaminated with a mixture of three biofilm-forming microorganisms (Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans) and disinfected immediately after contamination, or after microbial layers were allowed to develop during a six-hour storage. Two commercial disinfectants were tested: MD 520 containing 0.5% glutaraldehyde and Sterigum Powder without glutaraldehyde. Residual contamination was recovered by mechanical rinsing immediately after disinfection and after a six-hour storage of disinfected impressions, and assessed by colony counting. Both disinfectants tested were shown to be effective in reducing the microbial presence on the impression materials, achieving at least a 102 reduction of microbial counts compared to water rinsing. However, Sterigum was generally less effective on the Elite elastomer and could not grant disinfection on six-hour aged P. aeruginosa and C. albicans microbial layers. The results of this study suggest that the materials used for the impressions influence the efficacy of disinfection. Disinfectants should be tested according to conditions encountered in everyday clinical practice and the need for immediate disinfection of impressions should be clearly indicated by manufacturers.

  13. In-Use Evaluation of Peracetic Acid for High-Level Disinfection of Endoscopes.

    Science.gov (United States)

    Chenjiao, Wu; Hongyan, Zhang; Qing, Gu; Xiaoqi, Zhong; Liying, Gu; Ying, Fang

    2016-01-01

    Many high-level disinfectants have been used for disinfection of endoscopes such as 2% glutaraldehyde (GA), 0.55% ortho-phthalaldehyde (OPA), and peracetic acid (PAA). Both GA and OPA are widely used in disinfection of endoscopes and have been previously discussed, but there is little research on the practical use of PAA as an endoscope disinfectant. An experimental model of a flexible gastrointestinal endoscope being contaminated with 9 strains of microorganism was designed. After the cleaning and disinfecting procedure was completed, we evaluated the biocidal activity (850 ppm PAA, 2% GA, and 0.55% OPA) on our flexible gastrointestinal endoscope model. We also evaluated sterilization effectiveness of PAA on other bacteria, including some antibiotic-resistant bacteria (methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus, and Clostridium difficile). The residual bacterial colony count number of the PAA-disinfected endoscope was significantly lower than that of the GA- and OPA-disinfected endoscopes. The biocidal effect and efficiency of the endoscope disinfection by PAA appeared to be better than either the GA- or OPA-disinfected endoscope. PAA has demonstrated a good sterilization effect on other bacterial species; of particular note are common antibiotic-resistant bacteria such as methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus, and Clostridium difficile. The results of this study demonstrate that PAA is a fast and effective high-level disinfectant for use in the reprocessing of flexible endoscopes.

  14. Toxic impact of bromide and iodide on drinking water disinfected with chlorine or chloramines.

    Science.gov (United States)

    Yang, Yang; Komaki, Yukako; Kimura, Susana Y; Hu, Hong-Ying; Wagner, Elizabeth D; Mariñas, Benito J; Plewa, Michael J

    2014-10-21

    Disinfectants inactivate pathogens in source water; however, they also react with organic matter and bromide/iodide to form disinfection byproducts (DBPs). Although only a few DBP classes have been systematically analyzed for toxicity, iodinated and brominated DBPs tend to be the most toxic. The objectives of this research were (1) to determine if monochloramine (NH2Cl) disinfection generated drinking water with less toxicity than water disinfected with free chlorine (HOCl) and (2) to determine the impact of added bromide and iodide in conjunction with HOCl or NH2Cl disinfection on mammalian cell cytotoxicity and genomic DNA damage induction. Water disinfected with chlorine was less cytotoxic but more genotoxic than water disinfected with chloramine. For both disinfectants, the addition of Br(-) and I(-) increased cytotoxicity and genotoxicity with a greater response observed with NH2Cl disinfection. Both cytotoxicity and genotoxicity were highly correlated with TOBr and TOI. However, toxicity was weakly and inversely correlated with TOCl. Thus, the forcing agents for cytotoxicity and genotoxicity were the generation of brominated and iodinated DBPs rather than the formation of chlorinated DBPs. Disinfection practices need careful consideration especially when using source waters containing elevated bromide and iodide.

  15. Observations on Salmonella contamination of commercial duck farms before and after cleaning and disinfection.

    Science.gov (United States)

    Martelli, Francesca; Gosling, Rebecca J; Callaby, Rebecca; Davies, Rob

    2017-04-01

    In the European Union, statutory control of Salmonella is in place in the chicken and turkey sectors, but not in the duck sector. In this study, 14 Salmonella-positive duck farms were sampled before and after cleaning and disinfection, and once the houses had been restocked with a new flock. The cleaning and disinfection programmes used were subdivided into two main categories: ones in which a final formaldehyde disinfection step was included (1) and ones in which it was not included (2). Several types of samples were collected during the study, and faecal samples were those more frequently positive (62% of faecal samples were positive for Salmonella in comparison to 2-23% of samples from all the other sample categories) (P cleaning and disinfection programme used, there was a statistically significant (P cleaning and disinfection (41.1%) and after cleaning and disinfection (3.1%). After restocking, the number of Salmonella-positive samples increased significantly (P disinfection programme 1 was used were 5.34 times less likely to have samples positive for Salmonella after cleaning and disinfection than farms which implemented programme 2. Formaldehyde acts effectively against Salmonella even in the presence of some residual organic matter. Limited residual contamination on farms after cleaning and disinfection represents a risk of infection for young ducklings, and thorough cleaning and disinfection procedures should be implemented to reduce the carry-over of infection between flocks.

  16. Resistance of Pseudomonas aeruginosa isolates to hydrogel contact lens disinfection correlates with cytotoxic activity.

    Science.gov (United States)

    Lakkis, C; Fleiszig, S M

    2001-04-01

    One of the most common pathogens in infection of hydrogel contact lens wearers is Pseudomonas aeruginosa, which can gain access to the eye via contamination of the lens, lens case, and lens care solutions. Only one strain per species is used in current regulatory testing for the marketing of chemical contact lens disinfectants. The aim of this study was to determine whether P. aeruginosa strains vary in their susceptibility to hydrogel contact lens disinfectants. A method for rapidly screening bacterial susceptibility to contact lens disinfectants was developed, based on measurement of the MIC. The susceptibility of 35 P. aeruginosa isolates to two chemical disinfectants was found to vary among strains. MICs ranged from 6.25 to 100% for both disinfectants at 37 degrees C, and a number of strains were not inhibited by a 100% disinfectant concentration in the lens case environment at room temperature (22 degrees C). Resistance to disinfection appeared to be an inherent rather than acquired trait, since some resistant strains had been isolated prior to the introduction of the disinfectants and some susceptible P. aeruginosa strains could not be made more resistant by repeated disinfectant exposure. A number of P. aeruginosa strains which were comparatively more resistant to short-term disinfectant exposure also demonstrated the ability to grow to levels above the initial inoculum in one chemical disinfectant after long-term (24 to 48 h) disinfectant exposure. Resistance was correlated with acute cytotoxic activity toward corneal epithelial cells and with exsA, which encodes a protein that regulates cytotoxicity via a complex type III secretion system. These results suggest that chemical disinfection solutions may select for contamination with cytotoxic strains. Further investigation of the mechanisms and factors responsible for resistance may also lead to strategies for reducing adverse responses to contact lens wear.

  17. Study on a New Ultraviolet Sterilizer to the Surface Disinfection of the Ultrasound Probe.

    Science.gov (United States)

    Chen, Gui Qiu; Chen, Yu Hao; Yi, Liang; Yin, Jin; Gao, Qiong; Song, Jiang Nan; Li, Shi Kang; Chen, Pei Hou; Guo, Gui Ping

    2018-02-01

    We studied the disinfection effect of a new ultraviolet (UV) sterilizer and its utilization on ultrasound probe surfaces. Carrier quantitative germicidal tests, simulated on-the-spot trials, and organic substance influence tests were used to carry out experimental observation. Artificially infected probes were disinfected using the sterilizer or a germicidal lamp for comparison. The total number and types of bacteria were determined and identified. Our results demonstrated the sterilizer had the best disinfection effect among three different disinfection methods in hospital. The sterilizer has been used in a hospital setting for 2 years with no notable damage to the ultrasound probe instrument. It has the advantages of fast disinfection, high disinfection effect, and good compatibility with the ultrasound instrument, worthy of being a promoted application in medical institutions. Copyright © 2018 The Editorial Board of Biomedical and Environmental Sciences. Published by China CDC. All rights reserved.

  18. Activity of disinfectants against foodborne pathogens in suspension and adhered to stainless steel surfaces

    Directory of Open Access Journals (Sweden)

    Tatiane Karen Cabeça

    2012-09-01

    Full Text Available The purpose of this study was to investigate and compare the efficacy of various disinfectants on planktonic cells and biofilm cells of Listeria monocytogenes, Staphylococcus aureus and Escherichia coli. Numbers of viable biofilm cells decreased after treatment with all tested disinfectants (iodine, biguanide, quaternary ammonium compounds, peracetic acid and sodium hypochlorite. Sodium hypochlorite was the most effective disinfectant against biofilm cells, while biguanide was the least effective. Scanning electron microscopy observations revealed that cells adhered on stainless steel surface after treatment with the disinfectants. No viable planktonic cells were observed after treatment with the same disinfectants. Based on our findings, we concluded that biofilm cells might be more resistant to disinfectants than plancktonic cells.

  19. Thermal disinfection of hotels, hospitals, and athletic venues hot water distribution systems contaminated by Legionella species.

    Science.gov (United States)

    Mouchtouri, Varvara; Velonakis, Emmanuel; Hadjichristodoulou, Christos

    2007-11-01

    Legionella spp. (> or = 500 cfu liter(-1)) were detected in 92 of 497 water distribution systems (WDS) examined. Thermal disinfection was applied at 33 WDS. After the first and second application of the disinfection procedure, 15 (45.4%) and 3 (9%) positive for remedial actions WDS were found, respectively. Legionella pneumophila was more resistant to thermal disinfection than Legionella non-pneumophila spp. (relative risk [RR]=5.4, 95% confidence intervals [CI]=1-35). WDS of hotels with oil heater were more easily disinfected than those with electrical or solar heater (RR=0.4 95% CI=0.2-0.8). Thermal disinfection seems not to be efficient enough to eliminate legionellae, unless repeatedly applied and in combination with extended heat flushing, and faucets chlorine disinfection.

  20. Chemical surface disinfection of eggs of Baltic cod, Gadus morhua L

    DEFF Research Database (Denmark)

    Overton, J L; Bruun, Morten Sichlau; Dalsgaard, Inger

    2010-01-01

    The effect of two disinfectants on eggs and larvae of Baltic cod, Gadus morhua, was investigated. The eggs were disinfected for 10 min using various concentrations of either glutaraldehyde (100, 200, 400, 600 and 800 mg L−1) or iodophor (10, 50, 100 and 150 mg L−1), 1–4-days post......-fertilization. Bactericidal effect of disinfection, survival to hatching, hatching success and larval abnormalities were assessed. Larval survival was recorded at 5-, 10- and 15-days post-hatch (dph). Although Baltic cod eggs have an unusually thin chorion, they could tolerate surface disinfection. A reduction in bacterial...... growth was observed with increased concentrations of disinfectant (3.0 × 107–1.6 × 101 CFU mL−1). Abnormalities in newly hatched larvae were not related to disinfection. Survival of the yolk sac larvae was significantly better for eggs treated with 400 mg L−1 glutaraldehyde for 10 min at 10 and 15 dph...

  1. Laboratory and field investigation of chemical disinfection of combined sewer overflow in Copenhagen area

    DEFF Research Database (Denmark)

    Chhetri, Ravi Kumar; Thornberg, Dines; Berner, Jesper

    We investigated the possibility to apply performic acid (PFA) and peracetic acid (PAA) for disinfection of combined sewer overflow (CSO) in existing CSO management infrastructures. The disinfection power of PFA and PAA to Escherichia coli (E. coli) and enterococcus were studied in batch scale...... and pre-field experiment. In batch scale experiment 2.5 mg·L -1 PAA removed around 4 log unit of E. coli and enterococcus from CSO with long contact time. Removal of E. coli and enterococcus from CSO were always around or above 3 log unit using 2-4 mg·L -1 PFA with short contact time in batch scale...... and pre-field experiment. There were no toxicological effect measured by Vibrio fischeri when CSO was disinfected with PFA, slight toxicological effect was observed on CSO disinfected with PAA. When the design for PFA based disinfection was applied to CSO collected from an authentic event. Disinfection...

  2. Microbial electrolytic disinfection process for highly efficient Escherichia coli inactivation

    DEFF Research Database (Denmark)

    Zhou, Shaofeng; Huang, Shaobin; Li, Xiaohu

    2018-01-01

    extensively studied for recalcitrant organics removal, its application potential towards water disinfection (e.g., inactivation of pathogens) is still unknown. This study investigated the inactivation of Escherichia coli in a microbial electrolysis cell based bio-electro-Fenton system (renamed as microbial......Water quality deterioration caused by a wide variety of recalcitrant organics and pathogenic microorganisms has become a serious concern worldwide. Bio-electro-Fenton systems have been considered as cost-effective and highly efficient water treatment platform technology. While it has been......]OH was identified as one potential mechanism for disinfection. This study successfully demonstrated the feasibility of bio-electro-Fenton process for pathogens inactivation, which offers insight for the future development of sustainable, efficient, and cost-effective biological water treatment technology....

  3. Surface Dielectric Barrier Discharge Jet for Skin Disinfection

    Science.gov (United States)

    Creyghton, Yves; Meijer, Rogier; Verweij, Paul; van der Zanden, Frank; Leenders, Paul

    A consortium consisting of the research institute TNO, the medical ­university and hospital St Radboud and two industrial enterprises is working on a non-thermal plasma treatment method for hand disinfection. The group is seeking for cooperation, in particular in the field of validation methods and potential ­standardization for plasma based disinfection procedures. The present paper describes technical progress in plasma source development together with initial microbiological data. Particular properties of the sheet shaped plasma volume are the possibility of treating large irregular surfaces in a short period of time, effective plasma produced species transfer to the surface together with high controllability of the nature of plasma species by means of temperature conditioning.

  4. Chlorine dioxine DBPs (disinfection by-products in drinking water

    Directory of Open Access Journals (Sweden)

    C. Lasagna

    2013-01-01

    Full Text Available Since the 1970s it has been well known that, though water for human consumption is generally disinfected before being distributed along the network, the use of chemicals results in the formation of many different Disinfection By-Products (DBPs. In the case of chlorine dioxide, the most important and represented DBPs are chlorite and chlorate: after an introduction concerning the current Italian regulation on this subject, in the experimental part the results of a 7-year minitoring campaign, concerning water of different origin collected from taps in various Italian regions, are shown. The analytical technique used for the determination of chlorite and chlorate was Ion Chromatography. The result obtained are finally discussed.

  5. Disinfection of treated sewage. [Ultra-violet irradiation

    Energy Technology Data Exchange (ETDEWEB)

    From, J O

    1976-09-02

    The release of treated sewage in the vicinity of bathing places, drinking water sources or fish and shellfish culture plants is undesirable due to high bacterial content. Disinfection by chlorine would be relatively expensive and the toxicity would result in a local dead zone. The formation of small, but measurable, amounts of persistent chlorated hydrocarbons could also lead to long-term biological effects. Disinfection by ozone or gamma radiation would involve investments unacceptable in small plants. Ultraviolet radiation with wavelength 2500-2600 A has a powerful bacteriocidal effect and has been demonstrated to give bacterial mortality of 99.96 to 99.997 %. A standard plant produced in USA with a capacity of 11.3 m/sup 3//h is illustrated. UV radiation has no effect on the chemical composition of the water and the operating costs are low.

  6. Dose requirements for UVC disinfection of catheter biofilms

    DEFF Research Database (Denmark)

    Bak, Jimmy; Ladefoged, Søren D.; Tvede, Michael

    2009-01-01

    Bacterial biofilms on permanent catheters are the major sources of infection. Exposure to ultraviolet-C (UVC) light has been proposed as a method for disinfecting the inner surface of catheters. Specification of a UVC-based device for in vivo disinfection is based on the knowledge of the required...... doses to kill catheter biofilm. Given these doses and the power of available UVC light sources, calculation of the necessary treatment times is then possible. To determine the required doses, contaminated urinary catheters were used as test samples and UVC treated in vitro. Patient catheters (n = 67......) were collected and cut into segments of equal size and treated with various UVC doses. After treatment, the biofilm was removed by scraping and quantified by counting colony forming units. Percentage killing rates were determined by calculating ratios between UVC-treated samples and controls (no UVC...

  7. Sludge disinfection by combined treatment of bleaching powder and irradiation

    International Nuclear Information System (INIS)

    Harsoyo

    1987-01-01

    Sludge disinfection by combined treatment of bleaching powder and irradiation. Disinfection of sludge by combined treatment of bleaching powder and irradiation has been investigated. Sludge were obtained from water and waste sanitation department (Dinas Kebersihan) DKI located at Kebon Nanas, Jakarta. Sludge were mixed with bleaching powder at the concentration of 0, 10 and 20 mg/l and then irradiated in multipurpose panoramic batch irradiator (PANBIT) with doses of 2, 4, 6, 8, and 10 kGy and a dose rate 9 kGy/h. The reducing colony form unit caused by the combined treatment depend on type bacteria observed in sludge. Pathogenic bacteria as Clostridium still survive at a dose of 10 kGy on sludge containing 20 mg/l bleaching powder, but Salmonella, Shigella, and Vibrio were not detected in this experiment, neither in the control nor in the irradiated samples. (author). 14 refs.; 4 figs

  8. Solar disinfection of drinking water and oral rehydration solutions

    Energy Technology Data Exchange (ETDEWEB)

    Acra, A; Raffoul, Z; Karahagopian, Y

    1984-01-01

    This document provides concise information on oral rehydration therapy for the control of diarrheal diseases in developing countries; however, the main emphasis has been placed on the disinfection of oral rehydration solutions, or the water used in their preparation, as achieved by exposure to sunlight in transparent containers. The fundamental principles of solar energy are presented as well as studies which demonstrate the efficacy of the method. 2 figures, 6 tables.

  9. Inactivation Effect of Antibiotic-Resistant Gene Using Chlorine Disinfection

    Directory of Open Access Journals (Sweden)

    Takashi Furukawa

    2017-07-01

    Full Text Available The aim of this study was to elucidate the inactivation effects on the antibiotic-resistance gene (vanA of vancomycin-resistant enterococci (VRE using chlorination, a disinfection method widely used in various water treatment facilities. Suspensions of VRE were prepared by adding VRE to phosphate-buffered saline, or the sterilized secondary effluent of a wastewater treatment plant. The inactivation experiments were carried out at several chlorine concentrations and stirring time. Enterococci concentration and presence of vanA were determined. The enterococci concentration decreased as chlorine concentrations and stirring times increased, with more than 7.0 log reduction occurring under the following conditions: 40 min stirring at 0.5 mg Cl2/L, 20 min stirring at 1.0 mg Cl2/L, and 3 min stirring at 3.0 mg Cl2/L. In the inactivation experiment using VRE suspended in secondary effluent, the culturable enterococci required much higher chlorine concentration and longer treatment time for complete disinfection than the cases of suspension of VRE. However, vanA was detected in all chlorinated suspensions of VRE, even in samples where no enterococcal colonies were present on the medium agar plate. The chlorine disinfection was not able to destroy antibiotic-resistance genes, though it can inactivate and decrease bacterial counts of antibiotic-resistant bacteria (ARB. Therefore, it was suggested that remaining ARB and/or antibiotic-resistance gene in inactivated bacterial cells after chlorine disinfection tank could be discharged into water environments.

  10. Iodine Disinfection in the Use of Individual Water Purification Devices

    Science.gov (United States)

    2006-03-01

    Effect of Resin Disinfectants-I3 and –I5 on Giardia muris and Giardia lamblia. Applied and Environmental Microbiology, 46(5), 965-969. 24. AWWA... Giardia or Cryptosporidium). Iodine-using IWPDs meeting these standards are considered effective against disease causing bacteria, viruses, and...CT = 65 mg-min/L) for a 2-log inactivation of E. histolytica cysts (references 9 and 10). Another study using Giardia cysts showed CT’s up to 3

  11. Automation of air disinfection and lighting in agricultural buildings

    Directory of Open Access Journals (Sweden)

    L. Yu. Yuferev

    2017-01-01

    Full Text Available The article describes the urgency of this problem and modern ways of its solving. Modern disinfection and lighting systems are not developed enough. The authors proposed to automate the system of disinfection, dust removal and lighting in the farm building. We developed algorithm on the basis of which the universal program in the programming language C ++ was written. Assembled the microprocessor set ARDUINO. The program is included in the microprocessor ATMEGA, which is part of ARDUINO. As a basis for the disinfection system, a two-component ARUF device was used, which includes two decontaminating components: an ultraviolet lamp and an aerosol dispenser. Each of the algorithms (lighting and disinfection consists of 3 parts: data collection and analysis, control, data output to the display. The sequence of 3 parts is 1 cycle, then it repeated. In the first part on the basis of indications of sensors assignment to variables of some values was carried out. In the second part, based on the values of the variables, the decontamination and lighting devices are controlled. In the third part due to changing the screen number, variable, it is possible to switch the display and view the status of the installation and external parameters. The program, written on the basis of algorithms, is universal and suitable for almost any poultry and livestock buildings. All parameters (the time of the beginning and completion of the ARUV operation within 24 hours, the daily time of the illumination of a certain cycle, the maximum and minimum humidity, the duration of each cycle used for control and management are variables. Operator can set the items using the display in the menu.

  12. Suitability of electrolyzed oxidizing water for the disinfection of hard surfaces and equipment in radiology

    OpenAIRE

    Pintaric, Robert; Matela, Joze; Pintaric, Stefan

    2015-01-01

    Background Hospitals are faced with increasingly resistant strains of micro-organisms. When it comes to disinfection, individual parts of electronic equipment of angiology diagnostics such as patient couches of computer tomography (CT) and magnetic resonance imaging (MRI) scanners prove to be very hard to disinfect. Disinfectants of choice are therefore expected to possess properties such as rapid, residue-free action without any damaging effect on the sensitive electronic equipment. This pap...

  13. Exposure characteristics of familial cases of lung injury associated with the use of humidifier disinfectants

    OpenAIRE

    Park, Donguk; Leem, Jonghan; Lee, Kyoungmu; Lim, Heungkyu; Choi, Yeyong; Ahn, Jong-Ju; Lim, Sinye; Park, Jeongim; Choi, Kyungho; Lee, Naroo; Jung, Hyejung; Ha, Jongsik; Paek, Domyung

    2014-01-01

    Background This study describes 17 families with 38 lung injury patients (14 males, 24 females; 22 preschool-age children less than six years of age and 16 individuals of 13–50 years) who used disinfectant added to humidifiers in the home. Methods Clinical examination and humidifier disinfectant-use histories were taken, and a thorough home investigation was performed to assess exposure to humidifier disinfectant. Results Nine of the patients (three pregnant females, six preschool-age childre...

  14. Association of high-level humidifier disinfectant exposure with lung injury in preschool children.

    Science.gov (United States)

    Park, Dong-Uk; Ryu, Seung-Hun; Roh, Hyun-Suk; Lee, Eun; Cho, Hyun-Ju; Yoon, Jisun; Lee, So-Yeon; Cho, Young Ah; Do, Kyung-Hyun; Hong, Soo-Jong

    2018-03-01

    Children aged ≤6years reportedly account for 52% of victims of humidifier disinfectant-associated lung injuries. To evaluate the association of humidifier disinfectants with lung injury risk among children aged ≤6years. Patients with humidifier disinfectant-associated lung injuries (n=214) who were clinically evaluated to have a definite (n=108), probable (n=49), or possible (n=57) association with humidifier disinfectants as well as control patients (n=123) with lung injury deemed unlikely to be associated with humidifier disinfectant use were evaluated to determine factors associated with increased risk of humidifier disinfectant-associated lung injury using unconditional multiple logistic regression analysis. For estimated airborne humidifier disinfectant concentrations, risk of humidifier disinfectant-associated lung injury increased ≥two-fold in a dose-dependent manner in the highest quartile (Q4, 135-1443μg/m 3 ) compared with that in the lowest quartile (Q1, ≤33μg/m 3 ). Registered patients using more than two humidifier disinfectant brands were at an increased risk of humidifier disinfectant-associated lung injury (adjusted OR, 2.2; 95% confidence interval, 1.3-3.8) compared with those using only one brand. With respect to the duration of humidifier disinfectant use, risk of humidifier disinfectant-associated lung injury increased ≥two-fold in the lowest quartile (≤5months) compared with that in the highest quartile (≥14months; adjusted OR 0.3; 95% confidence interval, 0.2-0.6). Younger children are more vulnerable to HDLI when exposed to HD chemicals within short period in early life. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Antiviral activity of a novel composition of peracetic acid disinfectant on parvoviruses

    Science.gov (United States)

    Dagher, Fadi; Jiang, Jun; Tijssen, Peter; Laliberté, Jean-François

    2017-01-01

    Porcine parvoviruses (PPV) are known to be particularly resistant to many disinfectants used to control other non-enveloped viruses. However, effective disinfectants used against PPV are harsh and corrosive to animal health facilities and the environment. We propose a noncorrosive “green” disinfectant that generates peracetic acid in-situ and is capable of inactivating PPV completely at a 1% concentration for a 10-minute contact time. PMID:28154460

  16. Antifungal efficacy of hydrogen peroxide in dental unit waterline disinfection.

    Science.gov (United States)

    Szymańska, Jolanta

    2006-01-01

    The concentration and composition of fungal flora in dental unit waterlines (DUWL) were evaluated. For this purpose, water samples from unit reservoirs and high-speed handpieces, and biofilm samples from the waterline walls from units were collected. Subsequently, analogous samples from DUWL were taken before and after disinfection using agent containing hydrogen peroxide. In the examined samples, the yeast-like fungi Candida albicans and Candida curvata were found. The following species of mould were also identified: Aspergillus amstelodami, Aspergillus fumigatus, Aspergillus glaucus group, Aspergillus (=Eurotium herbariorum) repens, Citromyces spp., Geotrichum candidum, Penicillium (glabrum) frequentans, Penicillium pusillum, Penicillium turolense and Sclerotium sclerotiorum (Sclerotinia sclerotiorum). Before disinfection, Candida curvata and Candida albicans constituted the greatest proportion of the total fungi in the reservoirs water; in the water of handpieces--Candida albicans and Aspergillus glaucus group; and in the biofilm samples--Aspergillus glaucus group and Candida albicans. After disinfection, in all 3 kinds of samples, Candida albicans prevailed, constituting from 31.2-85.7 % of the total fungi. The application of agent containing hydrogen peroxide caused a significant decrease both in the number of total fungi and individual fungal species, which confirms the product effectiveness in fungal decontamination of DUWL.

  17. Sludge disinfection using gamma radiation: a sound option for Albuquerque

    International Nuclear Information System (INIS)

    Noland, P.D.; Khera, A.K.

    1980-01-01

    The City of Albuquerque has disposed of its anaerobically digested dried sludge cake on City and county parks for many years. If the City is to continue such beneficial use of sludge, it must now provide a supplementary disinfection process in order to meet the recent EPA regulations governing land application of sewage sludges. In light of these recent regulations and soaring costs of electrical energy, the City of Albuquerque recently completed a comprehensive sludge management study. This study is intended to supplement the areawide facilities plan completed in 1976. Among the various alternatives evaluated, the most feasible was the continued use of dried sludge cake on City parks and sale of excess sludge cake as an unlimited use soil conditioner and fertilizer. This sludge would be disinfected by gamma irradiation. The proposed solids management system would consist of two-stage anaerobic digestion and pipeline transfer to dewatering, disinfection, and stockpiling facilities at a remote tract approximately 5 miles from the treatment plant

  18. Thermodynamic properties of an emerging chemical disinfectant, peracetic acid.

    Science.gov (United States)

    Zhang, Chiqian; Brown, Pamela J B; Hu, Zhiqiang

    2018-04-15

    Peracetic acid (PAA or CH 3 COOOH) is an emerging disinfectant with a low potential to form carcinogenic disinfection by-products (DBPs). Basic thermodynamic properties of PAA are, however, absent or inconsistently reported in the literature. This review aimed to summarize important thermodynamic properties of PAA, including standard Gibbs energy of formation and oxidation-reduction (redox) potential. The standard Gibbs energies of formation of CH 3 COOOH (aq) , CH 3 COOOH (g) , CH 3 COOOH (l) , and CH 3 COOO (aq) - are -299.41kJ·mol -1 , -283.02kJ·mol -1 , -276.10kJ·mol -1 , and -252.60kJ·mol -1 , respectively. The standard redox potentials of PAA are 1.748V and 1.005V vs. standard hydrogen electrode (SHE) at pH 0 and pH 14, respectively. Under biochemical standard state conditions (pH 7, 25°C, 101,325Pa), PAA has a redox potential of 1.385V vs. SHE, higher than many disinfectants. Finally, the environmental implications of the thermodynamic properties of PAA were systematically discussed. Those properties can be used to predict the physicochemical and biological behavior of aquatic systems exposed to PAA. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Wastewater disinfection by combination of ultrasound and ultraviolet irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Naddeo, V., E-mail: vnaddeo@unisa.it [Department of Civil Engineering, University of Salerno, Via Ponte don Melillo, 1, 84084 Fisciano (Italy); Landi, M.; Belgiorno, V. [Department of Civil Engineering, University of Salerno, Via Ponte don Melillo, 1, 84084 Fisciano (Italy); Napoli, R.M.A. [Department of Environmental Science, University of Napoli Parthenope, Via Amm. F. Acton, 38, 80133 Napoli (Italy)

    2009-09-15

    Reclamation and reuse of wastewater is one of the most effective ways to alleviate water resource scarcity. In many countries very stringent limit for chlorination by-products such as trihalomethanes has been set for wastewater reuse. Accordingly, the use of alternative oxidation/disinfection systems should be evaluated as possible alternative to chlorine. Recently ultrasound (US) was found to be effective as pre-treatment for wastewater disinfection by UV irradiation. The aim of this work is to investigate the wastewater advanced treatment by simultaneous combination of UV and US in terms of bacteria inactivation (Total coliform and Escherichia coli) at pilot-scale. The pilot plant was composed of two reactors: US-UV reactor and UV reactor. The influence of different reaction times, respective US and UV dose and synergistic effect was tested and discussed for two different kinds of municipal wastewater. An important enhancement of UV disinfection ability has been observed in presence of US, especially with wastewater characterized by low transmittance. In particular the inactivation was greater for T. coliform than for E. coli. Furthermore, the results obtained showed also that the fouling formation on the lamps was slower in US-UV reactor than in UV reactor both with and without solar radiation.

  20. Wastewater disinfection by combination of ultrasound and ultraviolet irradiation

    International Nuclear Information System (INIS)

    Naddeo, V.; Landi, M.; Belgiorno, V.; Napoli, R.M.A.

    2009-01-01

    Reclamation and reuse of wastewater is one of the most effective ways to alleviate water resource scarcity. In many countries very stringent limit for chlorination by-products such as trihalomethanes has been set for wastewater reuse. Accordingly, the use of alternative oxidation/disinfection systems should be evaluated as possible alternative to chlorine. Recently ultrasound (US) was found to be effective as pre-treatment for wastewater disinfection by UV irradiation. The aim of this work is to investigate the wastewater advanced treatment by simultaneous combination of UV and US in terms of bacteria inactivation (Total coliform and Escherichia coli) at pilot-scale. The pilot plant was composed of two reactors: US-UV reactor and UV reactor. The influence of different reaction times, respective US and UV dose and synergistic effect was tested and discussed for two different kinds of municipal wastewater. An important enhancement of UV disinfection ability has been observed in presence of US, especially with wastewater characterized by low transmittance. In particular the inactivation was greater for T. coliform than for E. coli. Furthermore, the results obtained showed also that the fouling formation on the lamps was slower in US-UV reactor than in UV reactor both with and without solar radiation.

  1. Formation of trihalomethanes as disinfection byproducts in herbal spa pools.

    Science.gov (United States)

    Fakour, Hoda; Lo, Shang-Lien

    2018-04-09

    Herbal spa treatments are favorite recreational activities throughout the world. The water in spas is often disinfected to control pathogenic microorganisms and guarantee hygiene. However, chlorinated water may cause the formation of disinfection byproducts (DBPs). Although there have been many studies on DBP formation in swimming pools, the role of organic matter derived from herbal medicines applied in herbal spa water has been largely neglected. Accordingly, the present study investigated the effect of herbal medicines on the formation of trihalomethanes (THMs) in simulated herbal spa water. Water samples were collected from a spa pool, and then, disinfection and herbal addition experiments were performed in a laboratory. The results showed that the organic molecules introduced by the herbal medicines are significant precursors to the formation of THMs in spa pool water. Since at least 50% of THMs were produced within the first six hours of the reaction time, the presence of herbal medicines in spa water could present a parallel route for THM exposure. Therefore, despite the undeniable benefits of herbal spas, the effect of applied herbs on DBP formation in chlorinated water should be considered to improve the water quality and health benefits of spa facilities.

  2. Disinfection of bore well water with chlorine dioxide/sodium hypochlorite and hydrodynamic cavitation.

    Science.gov (United States)

    Wang, Yifei; Jia, Aiyin; Wu, Yue; Wu, Chunde; Chen, Lijun

    2015-01-01

    The effect of hydrodynamic cavitation (HC) on potable water disinfection of chemicals was investigated. The bore well water was introduced into HC set-up to examine the effect of HC alone and combination of HC and chemicals such as chlorine dioxide and sodium hypochlorite. The effect of inlet pressure and geometrical parameters on disinfection was studied using HC alone and the results showed that increasing inlet pressure and using more and bigger holes of orifice plates can result in a higher disinfection rates. When HC was combined with chemicals, HC can reduce the doses of the chemicals and shorten the time of disinfection. It was also found that the decrease in bacteria concentration followed a first-order kinetic model. As for the experiment of combination of HC and sodium hypochlorite for disinfection, HC not only improves the disinfection rate but also degrades natural organic matter and chloroform. Compared with only sodium hypochlorite disinfection, combined processes get higher disinfection rate and lower production of chloroform, particularly the pretreatment with HC enhances the disinfection rate by 32% and there is a simultaneous reduction in production of chloroform by 39%.

  3. TiO{sub 2}-based photocatalytic disinfection of microbes in aqueous media: A review

    Energy Technology Data Exchange (ETDEWEB)

    Laxma Reddy, P.Venkata [Program in Environmental Science and Engineering, University of Texas El Paso, El Paso, TX 799038 (United States); Kavitha, Beluri [Department of Pharmacology, Kamineni Institute of Medical Sciences, Dr. NTRUHS, Vijayawada, Andhra Pradesh 520008 (India); Kumar Reddy, Police Anil [School of Chemical Engineering, Yeungnam University, Gyeongsan, Gyeongbuk 38541 (Korea, Republic of); Kim, Ki-Hyun, E-mail: kkim61@hanyang.ac.kr [Department of Civil & Environmental Engineering, Hanyang University, 222 Wangsimni-Ro, Seoul 04763 (Korea, Republic of)

    2017-04-15

    The TiO{sub 2} based photocatalyst has great potential for the disinfection/inactivation of harmful pathogens (such as E.coli in aqueous media) along with its well-known usefulness on various chemical pollutants. The disinfection property of TiO{sub 2} is primarily attributed to surface generation of reactive oxygen species (ROS) as well as free metal ions formation. Furthermore, its disinfection capacity and overall performance can be significantly improved through modifications of the TiO{sub 2} material. In this review, we provide a brief survey on the effect of various TiO{sub 2} materials in the disinfection of a wide range of environmentally harmful microbial pathogens (e.g., bacteria, fungi, algae, and viruses) in aqueous media. The influencing factors (such as reactor design, water chemistry, and TiO{sub 2} modifications) of such processes are discussed along with the mechanisms of such disinfection. It is believed that the combined application of disinfection and decontamination will greatly enhance the utilization of TiO{sub 2} photocatalyst as a potential alternative to conventional methods of water purification. - Highlights: • The advent of industrialization jeopardized the quality of drinking water. • TiO{sub 2} photocatalysis holds promise both in the degradation of pollutants and for disinfection. • The applicability of TiO{sub 2}-based decontamination is explored for microbial disinfection. • Here we provide a comprehensive review on titania-based photocatalysts for disinfection.

  4. In Vitro Evaluation of Dimensional Stability of Alginate Impressions after Disinfection by Spray and Immersion Methods

    Directory of Open Access Journals (Sweden)

    Fahimeh Hamedi Rad

    2010-12-01

    Full Text Available Background and aims. The most common method for alginate impression disinfection is spraying it with disinfecting agents, but some studies have shown that these impressions can be immersed, too. The aim of this study was to evaluate the dimensional stability of alginate impressions following disinfecting by spray and immersion methods. Materials and methods. Four common disinfecting agents (Sodium Hypochlorite, Micro 10, Glutaraldehyde and Deconex were selected and the impressions (n=108 were divided into four groups (n=24 and eight subgroups (n=12 for disinfecting by any of the four above-mentioned agents by spray or immersion methods. The control group (n=12 was not disinfected. Then the impressions were poured by type III Dental Stone Plaster in a standard method. The results were analyzed by descriptive methods (mean and standard deviation, t-test, two-way analysis of variance (ANOVA and Duncan test, using SPSS 14.0 software for windows. Results. The mean changes of length and height were significant between the various groups and disinfecting methods. Regarding the length, the greatest and the least amounts were related to Deconex and Micro 10 in the immersion method, respectively. Regarding height, the greatest and the least amounts were related to Glutaraldehyde and Deconex in the immersion method, respectively. Conclusion. Disinfecting alginate impressions by Sodium Hypochlorite, Deconex and Glutaraldehyde by immersion method is not recommended and it is better to disinfect alginate impressions by spraying of Micro 10, Sodium Hypochlorite, Glutaraldehyde and immersion in Micro 10.

  5. Chlorine disinfection of grey water for reuse: effect of organics and particles.

    Science.gov (United States)

    Winward, Gideon P; Avery, Lisa M; Stephenson, Tom; Jefferson, Bruce

    2008-01-01

    Adequate disinfection of grey water prior to reuse is important to prevent the potential transmission of disease-causing microorganisms. Chlorine is a widely utilised disinfectant and as such is a leading contender for disinfection of grey water intended for reuse. This study examined the impact of organics and particles on chlorine disinfection of grey water, measured by total coliform inactivation. The efficacy of disinfection was most closely linked with particle size. Larger particles shielded total coliforms from inactivation and disinfection efficacy decreased with increasing particle size. Blending to extract particle-associated coliforms (PACs) following chlorine disinfection revealed that up to 91% of total coliforms in chlorinated grey water were particle associated. The organic concentration of grey water affected chlorine demand but did not influence the disinfection resistance of total coliforms when a free chlorine residual was maintained. Implications for urban water reuse are discussed and it is recommended that grey water treatment systems target suspended solids removal to ensure removal of PACs prior to disinfection.

  6. Practical considerations in the use of UV light for drinking water disinfection

    International Nuclear Information System (INIS)

    Jeyanayagam, S.; Cotton, C.

    2002-01-01

    Ultraviolet (UV) light was discovered approximately 150 years ago. The first commercial UV lamp was made in the early 1900s soon followed by the manufacture of the quartz sleeve. These technological advances allowed the first application of UV light for water disinfection in 1907 in France. In the mid 1980s, UV disinfection was named as a Best available technology (BAT) for wastewater disinfection in the United States. Fueled by the recent findings that UV disinfection can inactivate key pathogens at cost effective UV doses, the drinking water industry in North America is closely investigating its application in large installations. (author)

  7. The efficiency of water treatment and disinfection by means of ultraviolet radiation

    International Nuclear Information System (INIS)

    Sobotka, J.

    1993-01-01

    Advantages and disadvantages of various water disinfection methods are discussed. The report examines the effectiveness of combined chlorine treatment and UV irradiation method of water disinfection and describes methods of determining UV radiation intensity, α absorption coefficient and radiation dose by means of measuring equipment constructed by the author. The α absorption coefficient dependence on the colour and turbidity of water exposed to radiation is defined. Enchytraeus albidus was applied as bioindicator in UV radiation intensity and disinfection effects measurements. The influence of UV radiation on microbiological, physical, chemical, and toxicological properties of water was determined. Prototype devices for water disinfection with UV radiation were made. (author)

  8. The efficiency of water treatment and disinfection by means of ultraviolet radiation

    Energy Technology Data Exchange (ETDEWEB)

    Sobotka, J [Medical Academy, Warsaw (Poland). Inst. of Social Medicine

    1993-01-01

    Advantages and disadvantages of various water disinfection methods are discussed. The report examines the effectiveness of combined chlorine treatment and UV irradiation method of water disinfection and describes methods of determining UV radiation intensity, [alpha] absorption coefficient and radiation dose by means of measuring equipment constructed by the author. The [alpha] absorption coefficient dependence on the colour and turbidity of water exposed to radiation is defined. Enchytraeus albidus was applied as bioindicator in UV radiation intensity and disinfection effects measurements. The influence of UV radiation on microbiological, physical, chemical, and toxicological properties of water was determined. Prototype devices for water disinfection with UV radiation were made. (author).

  9. Decontamination of B. globigii spores from drinking water infrastructure using disinfectants

    Data.gov (United States)

    U.S. Environmental Protection Agency — Decontamination of Bacillus spores adhered to common drinking water infrastructure surfaces was evaluated using a variety of disinfectants. Corroded iron and...

  10. Impact of universal disinfectant cap implementation on central line-associated bloodstream infections.

    Science.gov (United States)

    Merrill, Katreena Collette; Sumner, Sharon; Linford, Lorraine; Taylor, Carrie; Macintosh, Christopher

    2014-12-01

    Central line-associated bloodstream infections (CLABSIs) result in increased length of stay, cost, and patient morbidity and mortality. One CLABSI prevention method is disinfection of intravenous access points. The literature suggests that placing disinfectant caps over needleless connectors decreases CLABSI risk. A quasi-experimental intervention study was conducted in a >430-bed trauma I center. In addition to an existing standard central line bundle, a new intervention consisting of a luer-lock disinfectant cap with 70% alcohol was implemented in all intravenous (IV) needleless connectors on patients with peripheral and central lines. Compliance to the disinfectant cap was monitored weekly. A generalized linear model using a Poisson distribution was fit to determine if there were significant relationships between CLABSIs and disinfectant cap use. Impacts on costs were also examined. The rate of CLABSI decreased following implementation of the disinfectant cap. The incidence rate ratios (.577, P = .004) for implementing the disinfectant caps was statistically significant, indicating that the rate of patient infections decreased by >40%. Increased compliance rates were associated with lower infection rates. Disinfectant cap use was associated with an estimated savings of almost $300,000 per year in the hospital studied. Use of a disinfectant cap on IV needleless connectors in addition to an existing standard central line bundle was associated with decreased CLABSI and costs. Copyright © 2014 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

  11. Evaluation of disinfectants in the domestic environment under 'in use' conditions.

    Science.gov (United States)

    Scott, E.; Bloomfield, S. F.; Barlow, C. G.

    1984-01-01

    An 'in use' test was developed to investigate effectiveness of disinfectant application and of detergent of hot water cleaning at kitchen, bathroom and toilet sites in the domestic environment. Detergent and hot water cleaning produced no observable reduction in microbial contamination. Single and daily application tests demonstrated that hypochlorite and phenolic disinfectants can be used to produce substantial reductions in bacterial contamination in the home. Results indicate that maximum protection afforded by disinfection is relatively brief; 3-6 h after disinfection, contamination levels were only marginally less than those observed at pretreatment. Some suggestions are made for improvements in home hygiene. PMID:6323576

  12. Resistance of bacterial biofilms formed on stainless steel surface to disinfecting agent.

    Science.gov (United States)

    Królasik, Joanna; Zakowska, Zofia; Krepska, Milena; Klimek, Leszek

    2010-01-01

    The natural ability of microorganisms for adhesion and biofilm formation on various surfaces is one of the factors causing the inefficiency of a disinfection agent, despite its proven activity in vitro. The aim of the study was to determine the effectiveness of disinfecting substances on bacterial biofilms formed on stainless steel surface. A universally applied disinfecting agent was used in the tests. Bacterial strains: Listeria innocua, Pseudomonas putida, Micrococcus luteus, Staphylococcus hominis strains, were isolated from food contact surfaces, after a cleaning and disinfection process. The disinfecting agent was a commercially available acid specimen based on hydrogen peroxide and peroxyacetic acid, the substance that was designed for food industry usage. Model tests were carried out on biofilm formed on stainless steel (type 304, no 4 finish). Biofilms were recorded by electron scanning microscope. The disinfecting agent in usable concentration, 0.5% and during 10 minutes was ineffective for biofilms. The reduction of cells in biofilms was only 1-2 logarithmic cycles. The use of the agent in higher concentration--1% for 30 minutes caused reduction of cell number by around 5 logarithmic cycles only in the case of one microorganism, M. luteus. For other types: L. innocua, P. putida, S. hominis, the requirements placed on disinfecting agents were not fulfilled. The results of experiments proved that bacterial biofilms are resistant to the disinfectant applied in its operational parameters. Disinfecting effectiveness was achieved after twofold increase of the agent's concentration.

  13. Effective reprocessing of reusable dispensers for surface disinfection tissues – the devil is in the details

    Science.gov (United States)

    Kampf, Günter; Degenhardt, Stina; Lackner, Sibylle; Ostermeyer, Christiane

    2014-01-01

    Background: It has recently been reported that reusable dispensers for surface disinfection tissues may be contaminated, especially with adapted Achromobacter species 3, when products based on surface-active ingredients are used. Fresh solution may quickly become recontaminated if dispensers are not processed adequately. Methods: We evaluated the abilities of six manual and three automatic processes for processing contaminated dispensers to prevent recolonisation of a freshly-prepared disinfectant solution (Mikrobac forte 0.5%). Dispensers were left at room temperature for 28 days. Samples of the disinfectant solution were taken every 7 days and assessed quantitatively for bacterial contamination. Results: All automatic procedures prevented recolonisation of the disinfectant solution when a temperature of 60–70°C was ensured for at least 5 min, with or without the addition of chemical cleaning agents. Manual procedures prevented recontamination of the disinfectant solution when rinsing with hot water or a thorough cleaning step was performed before treating all surfaces with an alcohol-based disinfectant or an oxygen-releaser. Other cleaning and disinfection procedures, including the use of an alcohol-based disinfectant, did not prevent recolonisation. Conclusions: These results indicate that not all processes are effective for processing reusable dispensers for surface-disinfectant tissues, and that a high temperature during the cleaning step or use of a biofilm-active cleaning agent are essential. PMID:24653973

  14. Effective reprocessing of reusable dispensers for surface disinfection tissues – the devil is in the details

    Directory of Open Access Journals (Sweden)

    Kampf, Günter

    2014-03-01

    Full Text Available [english] Background: It has recently been reported that reusable dispensers for surface disinfection tissues may be contaminated, especially with adapted , when products based on surface-active ingredients are used. Fresh solution may quickly become recontaminated if dispensers are not processed adequately. Methods: We evaluated the abilities of six manual and three automatic processes for processing contaminated dispensers to prevent recolonisation of a freshly-prepared disinfectant solution (Mikrobac forte 0.5%. Dispensers were left at room temperature for 28 days. Samples of the disinfectant solution were taken every 7 days and assessed quantitatively for bacterial contamination. Results: All automatic procedures prevented recolonisation of the disinfectant solution when a temperature of 60–70°C was ensured for at least 5 min, with or without the addition of chemical cleaning agents. Manual procedures prevented recontamination of the disinfectant solution when rinsing with hot water or a thorough cleaning step was performed before treating all surfaces with an alcohol-based disinfectant or an oxygen-releaser. Other cleaning and disinfection procedures, including the use of an alcohol-based disinfectant, did not prevent recolonisation.Conclusions: These results indicate that not all processes are effective for processing reusable dispensers for surface-disinfectant tissues, and that a high temperature during the cleaning step or use of a biofilm-active cleaning agent are essential.

  15. Herd-Level Mastitis-Associated Costs on Canadian Dairy Farms

    Directory of Open Access Journals (Sweden)

    Mahjoob Aghamohammadi

    2018-05-01

    Full Text Available Mastitis imposes considerable and recurring economic losses on the dairy industry worldwide. The main objective of this study was to estimate herd-level costs incurred by expenditures and production losses associated with mastitis on Canadian dairy farms in 2015, based on producer reports. Previously, published mastitis economic frameworks were used to develop an economic model with the most important cost components. Components investigated were divided between clinical mastitis (CM, subclinical mastitis (SCM, and other costs components (i.e., preventive measures and product quality. A questionnaire was mailed to 374 dairy producers randomly selected from the (Canadian National Dairy Study 2015 to collect data on these costs components, and 145 dairy producers returned a completed questionnaire. For each herd, costs due to the different mastitis-related components were computed by applying the values reported by the dairy producer to the developed economic model. Then, for each herd, a proportion of the costs attributable to a specific component was computed by dividing absolute costs for this component by total herd mastitis-related costs. Median self-reported CM incidence was 19 cases/100 cow-year and mean self-reported bulk milk somatic cell count was 184,000 cells/mL. Most producers reported using post-milking teat disinfection (97% and dry cow therapy (93%, and a substantial proportion of producers reported using pre-milking teat disinfection (79% and wearing gloves during milking (77%. Mastitis costs were substantial (662 CAD per milking cow per year for a typical Canadian dairy farm, with a large portion of the costs (48% being attributed to SCM, and 34 and 15% due to CM and implementation of preventive measures, respectively. For SCM, the two most important cost components were the subsequent milk yield reduction and culling (72 and 25% of SCM costs, respectively. For CM, first, second, and third most important cost components were

  16. Herd-Level Mastitis-Associated Costs on Canadian Dairy Farms

    Science.gov (United States)

    Aghamohammadi, Mahjoob; Haine, Denis; Kelton, David F.; Barkema, Herman W.; Hogeveen, Henk; Keefe, Gregory P.; Dufour, Simon

    2018-01-01

    Mastitis imposes considerable and recurring economic losses on the dairy industry worldwide. The main objective of this study was to estimate herd-level costs incurred by expenditures and production losses associated with mastitis on Canadian dairy farms in 2015, based on producer reports. Previously, published mastitis economic frameworks were used to develop an economic model with the most important cost components. Components investigated were divided between clinical mastitis (CM), subclinical mastitis (SCM), and other costs components (i.e., preventive measures and product quality). A questionnaire was mailed to 374 dairy producers randomly selected from the (Canadian National Dairy Study 2015) to collect data on these costs components, and 145 dairy producers returned a completed questionnaire. For each herd, costs due to the different mastitis-related components were computed by applying the values reported by the dairy producer to the developed economic model. Then, for each herd, a proportion of the costs attributable to a specific component was computed by dividing absolute costs for this component by total herd mastitis-related costs. Median self-reported CM incidence was 19 cases/100 cow-year and mean self-reported bulk milk somatic cell count was 184,000 cells/mL. Most producers reported using post-milking teat disinfection (97%) and dry cow therapy (93%), and a substantial proportion of producers reported using pre-milking teat disinfection (79%) and wearing gloves during milking (77%). Mastitis costs were substantial (662 CAD per milking cow per year for a typical Canadian dairy farm), with a large portion of the costs (48%) being attributed to SCM, and 34 and 15% due to CM and implementation of preventive measures, respectively. For SCM, the two most important cost components were the subsequent milk yield reduction and culling (72 and 25% of SCM costs, respectively). For CM, first, second, and third most important cost components were culling (48

  17. Fibrous Catalyst-Enhanced Acanthamoeba Disinfection by Hydrogen Peroxide.

    Science.gov (United States)

    Kilvington, Simon; Winterton, Lynn

    2017-11-01

    Hydrogen peroxide (H2O2) disinfection systems are contact-lens-patient problem solvers. The current one-step, criterion-standard version has been widely used since the mid-1980s, without any significant improvement. This work identifies a potential next-generation, one-step H2O2, not based on the solution formulation but rather on a case-based peroxide catalyst. One-step H2O2 systems are widely used for contact lens disinfection. However, antimicrobial efficacy can be limited because of the rapid neutralization of the peroxide from the catalytic component of the systems. We studied whether the addition of an iron-containing catalyst bound to a nonfunctional propylene:polyacryonitrile fabric matrix could enhance the antimicrobial efficacy of these one-step H2O2 systems. Bausch + Lomb PeroxiClear and AOSept Plus (both based on 3% H2O2 with a platinum-neutralizing disc) were the test systems. These were tested with and without the presence of the catalyst fabric using Acanthamoeba cysts as the challenge organism. After 6 hours' disinfection, the number of viable cysts was determined. In other studies, the experiments were also conducted with biofilm formed by Stenotrophomonas maltophilia and Elizabethkingia meningoseptica bacteria. Both control systems gave approximately 1-log10 kill of Acanthamoeba cysts compared with 3.0-log10 kill in the presence of the catalyst (P catalyst compared with ≥3.0-log10 kill when it was omitted. In 30 rounds' recurrent usage, the experiments, in which the AOSept Plus system was subjected to 30 rounds of H2O2 neutralization with or without the presence of catalytic fabric, showed no loss in enhanced biocidal efficacy of the material. The catalytic fabric was also shown to not retard or increase the rate of H2O2 neutralization. We have demonstrated the catalyst significantly increases the efficacy of one-step H2O2 disinfection systems using highly resistant Acanthamoeba cysts and bacterial biofilm. Incorporating the catalyst into the

  18. Calcium hypochlorite as a disinfecting additive for dental stone.

    Science.gov (United States)

    Twomey, Jonathan O; Abdelaziz, Khalid M; Combe, Edward C; Anderson, Dwight L

    2003-09-01

    Dental casts come into direct contact with impression materials and other items that are contaminated by saliva and blood from a patient's mouth, leaving the casts susceptible to cross-contamination. Topical methods of disinfecting casts are difficult to control, while immersion methods are potentially destructive. Thus, an additional method to control cross-contamination between patients and laboratory personnel is needed. This study was undertaken in an attempt to develop a dental stone with disinfecting properties and adequate compressive and tensile strengths. Calcium hypochlorite [Ca(OCl)(2)] in aqueous solution in concentrations from 0 to 1.5% was tested as a disinfecting additive to type V dental stone. The compressive and tensile strength properties of the modified stone were measured (MPa) using a universal testing machine at a consistency similar to unmodified stone. Strength data were analyzed by 1-way ANOVA and post hoc Tukey-Kramer procedure (alpha CaviCide, and 3 impressions rinsed in water served as controls. In general, the effect of adding the disinfectant to the stone was a decrease in strength. Exceptions were the dry compressive strength, for which there was a significant increase in strength (P=.048) at 0.5%, and the wet compressive and wet tensile strength, which showed no significant difference between the 1.5% and the control. When Ca(OCl)(2) was added at the concentration 0.5% (2765 ppm available chlorine), the gypsum had acceptable mechanical properties; dry compressive strength was 78.86 +/- 4.12 MPa, and dry tensile strength was 10.64 +/- 1.27 MPa, compared to control values of 67.85 +/- 6.28 and 13.41 +/- 1.24 MPa, respectively. At concentrations of 0.3% and higher (36 1650 ppm of available chlorine), calcium hypochlorite was able to completely inactivate phi29. It is possible to prepare a type V dental stone that contains a disinfectant, has adequate mechanical properties, and will reduce numbers of residual microorganisms. For example

  19. Disinfection efficacy of contact lens care solutions against ocular pathogens.

    Science.gov (United States)

    Miller, M J; Callahan, D E; McGrath, D; Manchester, R; Norton, S E

    2001-01-01

    Three commercially available products labeled as multi-purpose contact lens solutions, one multi-purpose disinfecting solution, and a hydrogen peroxide system were evaluated for antimicrobial activity according to the current International Organization for Standardization (ISO) and the U.S. Food and Drug Administration (FDA) stand-alone procedure for disinfecting products. One multi-purpose solution was selected to assess its antimicrobial activity against two human corneal isolates of Pseudomonas aeruginosa. Products were challenged with bacteria and fungi, and following a specified period, aliquots of inoculated test solution were neutralized and plated on validated recovery media. After incubation the number of viable microorganisms was enumerated and mean log reductions determined. ReNu MultiPlus (Bausch & Lomb, Rochester, NY), AOSEPT (CIBA Vision Corporation, Duluth, GA), and Opti-Free Express with Aldox (Alcon Laboratories, Ft. Worth, TX) were the only lens care products that met the stand-alone criteria for all required microorganisms within their minimum recommended disinfection time. Of these, ReNu MultiPlus provided the greatest overall antimicrobial activity. ReNu MultiPlus demonstrated a significantly higher mean log reduction of Staphylococcus aureus and Serratia marcescens than Opti-Free Express. ReNu MultiPlus also gave a higher mean log reduction of S. aureus and S. marcescens than AOSEPT, and a higher mean log reduction of Candida albicans and Fusarium solani than AOSEPT, Complete Comfort Plus (Allergan, Irivine, CA), and Solo-Care (CIBA Vision Corp.) (at 4 hours). Both Complete Comfort Plus and Solo-Care (at 4 hours) met the primary acceptance criteria for bacteria; however, neither product possessed enough antimicrobial activity to meet the minimum criteria for yeast or mold. ReNu Multiplus was effective against corneal isolates of P. aeruginosa. ReNu MultiPlus, AOSEPT, and Opti-Free Express met the requirements of the stand-alone primary

  20. Genotoxicity of drinking water treated with different disinfectants and effects of disinfection conditions detected by umu-test.

    Science.gov (United States)

    Nie, Xuebiao; Liu, Wenjun; Zhang, Liping; Liu, Qing

    2017-06-01

    The genotoxicity of drinking water treated with 6 disinfection methods and the effects of disinfection conditions were investigated using the umu-test. The pretreatment procedure of samples for the umu-test was optimized for drinking water analysis. The results of the umu-test were in good correlation with those of the Ames-test. The genotoxicity and production of haloacetic acids (HAAs) were the highest for chlorinated samples. UV+chloramination is the safest disinfection method from the aspects of genotoxicity, HAA production and inactivation effects. For chloramination, the effects of the mass ratio of Cl 2 to N of chloramine on genotoxicity were also studied. The changes of genotoxicity were different from those of HAA production, which implied that HAA production cannot represent the genotoxic potential of water. The genotoxicity per chlorine decay of chlorination and chloramination had similar trends, indicating that the reaction of organic matters and chlorine made a great contribution to the genotoxicity. The results of this study are of engineering significance for optimizing the operation of waterworks. Copyright © 2016. Published by Elsevier B.V.

  1. Peracetic acid (PAA) disinfection of primary, secondary and tertiary treated municipal wastewaters.

    Science.gov (United States)

    Koivunen, J; Heinonen-Tanski, H

    2005-11-01

    The efficiency of peracetic acid (PAA) disinfection against enteric bacteria and viruses in municipal wastewaters was studied in pilot-scale. Disinfection pilot-plant was fed with the primary or secondary effluent of Kuopio municipal wastewater treatment plant or tertiary effluent from the pilot-scale dissolved air flotation (DAF) unit. Disinfectant doses ranged from 2 to 7 mg/l PAA in the secondary and tertiary effluents, and from 5 to 15 mg/l PAA in the primary effluents. Disinfection contact times were 4-27 min. Disinfection of secondary and tertiary effluents with 2-7 mg/l PAA and 27 min contact time achieved around 3 log reductions of total coliforms (TC) and enterococci (EC). PAA disinfection also significantly improved the hygienic quality of the primary effluents: 10-15 mg/l PAA achieved 3-4 log reductions of TC and EC, 5 mg/l PAA resulting in below 2 log reductions. F-RNA coliphages were more resistant against the PAA disinfection and around 1 log reductions of these enteric viruses were typically achieved in the disinfection treatments of the primary, secondary and tertiary effluents. Most of the microbial reductions occurred during the first 4-18 min of contact time, depending on the PAA dose and microorganism. The PAA disinfection efficiency remained relatively constant in the secondary and tertiary effluents, despite of small changes of wastewater quality (COD, SS, turbidity, 253.7 nm transmittance) or temperature. The disinfection efficiency clearly decreased in the primary effluents with substantially higher microbial, organic matter and suspended solids concentrations. The results demonstrated that PAA could be a good alternative disinfection method for elimination of enteric microbes from different wastewaters.

  2. Modern technologies for improving cleaning and disinfection of environmental surfaces in hospitals.

    Science.gov (United States)

    Boyce, John M

    2016-01-01

    Experts agree that careful cleaning and disinfection of environmental surfaces are essential elements of effective infection prevention programs. However, traditional manual cleaning and disinfection practices in hospitals are often suboptimal. This is often due in part to a variety of personnel issues that many Environmental Services departments encounter. Failure to follow manufacturer's recommendations for disinfectant use and lack of antimicrobial activity of some disinfectants against healthcare-associated pathogens may also affect the efficacy of disinfection practices. Improved hydrogen peroxide-based liquid surface disinfectants and a combination product containing peracetic acid and hydrogen peroxide are effective alternatives to disinfectants currently in widespread use, and electrolyzed water (hypochlorous acid) and cold atmospheric pressure plasma show potential for use in hospitals. Creating "self-disinfecting" surfaces by coating medical equipment with metals such as copper or silver, or applying liquid compounds that have persistent antimicrobial activity surfaces are additional strategies that require further investigation. Newer "no-touch" (automated) decontamination technologies include aerosol and vaporized hydrogen peroxide, mobile devices that emit continuous ultraviolet (UV-C) light, a pulsed-xenon UV light system, and use of high-intensity narrow-spectrum (405 nm) light. These "no-touch" technologies have been shown to reduce bacterial contamination of surfaces. A micro-condensation hydrogen peroxide system has been associated in multiple studies with reductions in healthcare-associated colonization or infection, while there is more limited evidence of infection reduction by the pulsed-xenon system. A recently completed prospective, randomized controlled trial of continuous UV-C light should help determine the extent to which this technology can reduce healthcare-associated colonization and infections. In conclusion, continued efforts to

  3. Evaluation of possible use of disinfectant based on chlorine dioxide in dairy plant

    Directory of Open Access Journals (Sweden)

    Rakić-Martinez Mira

    2009-01-01

    Full Text Available Poor sanitation of food contact surfaces has been a contributing factor in food borne disease outbreaks, especially those involving Listeria monocytogenes, Salmonella spp., Escherichia coli, Staphylococcus aureus etc. The objectives of this study were therefore to: 1. Determine the efficiency of a disinfectant based on chlorine dioxide in suspension in a closed system in a dairy plant. 2. Evaluate the possibility of disinfection of working surfaces with a disinfectant based on chlorine dioxide. In order to determine the germicidal effect of the disinfectant based on chlorine dioxide by suspension test (BSEN 1276:1997; the following test organisms were used: Listeria monocytogenes, Proteus mirabilis, Escherichia coli, Bacillus cereus, Staphylococcus aureus and Pseudomonas aeruginosa clinical isolate. The corrosive properties of the disinfectant based on chlorine dioxide were tested by IDF 077:1977 standard. The efficacy of this disinfectant was investigated in a closed system in a dairy plant. Results indicated a 100% reduction of >108 cfu/ml L. monocytogenes, E. coli, Proteus mirabilis, Pseudomonas aeruginosa, S. aureus, viable count after 1 minute of exposure to 100 ppm of the disinfectant based on chlorine dioxide and 400 ppm for Bacillus cereus. In the presence of 2% skim milk and 4 % skim milk concentrations of 200 and 250 ppm resulted in 100% reduction in numbers of the five of six test microorganisms, respectively. The spore former, Bacillus cereus is less susceptible to the disinfectant. Therefore, the efficient concentration for 100% reduction in viable count after 1 minute exposure was 500 ppm. The corrosive properties of the disinfectant were not determined. In the case of closed system disinfection in a dairy plant, reduction in viable count after 15 minute exposure to 100 ppm of disinfectant based on chlorine dioxide ranged from 80 to 100%.

  4. Efficacy of computer-based endoscope cleaning and disinfection using a hospital management information system.

    Science.gov (United States)

    Wang, Caixia; Chen, Yuanyuan; Yang, Feng; Ren, Jie; Yu, Xin; Wang, Jiani; Sun, Siyu

    2016-08-01

    The present study aimed to assess the efficacy of computer-based endoscope cleaning and disinfection using a hospital management information system (HMIS). A total of 2,674 gastroscopes were eligible for inclusion in this study. For the processes of disinfection management, the gastroscopes were randomly divided into 2 groups: gastroscope disinfection HMIS (GD-HMIS) group and manual group. In the GD-HMIS group, an integrated circuit card (IC card) chip was installed to monitor and record endoscope cleaning and disinfection automatically and in real time, whereas the endoscope cleaning and disinfection in the manual group was recorded manually. The overall disinfection progresses for both groups were recorded, and the total operational time was calculated. For the GD-HMIS group, endoscope disinfection HMIS software was successfully developed. The time to complete a single session of cleaning and disinfecting on a gastroscope was 15.6 minutes (range, 14.3-17.2 minutes) for the GD-HMIS group and 21.3 minutes (range, 20.2-23.9 minutes) for the manual group. Failure to record information, such as the identification number of the endoscope, occasionally occurred in the manual group, which affected the accuracy and reliability of manual recording. Computer-based gastroscope cleaning and disinfection using a hospital management information system could monitor the process of gastroscope cleaning and disinfection in real time and improve the accuracy and reliability, thereby ensuring the quality of gastroscope cleaning and disinfection. Copyright © 2016 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

  5. Effectiveness of various cleaning and disinfectant products on Clostridium difficile spores of PCR ribotypes 010, 014 and 027

    NARCIS (Netherlands)

    Kenters, N.; Huijskens, E.G.; Wit, S.C.J. de; Sanders, I.; Rosmalen, J. van; Kuijper, E.J.; Voss, A.

    2017-01-01

    BACKGROUND: In healthcare facilities, Clostridium difficile infections spread by transmission of bacterial spores. Appropriate sporicidal disinfectants are needed to prevent development of clusters and outbreaks. In this study different cleaning/disinfecting wipes and sprays were tested for their

  6. Effectiveness of various cleaning and disinfectant products on Clostridium difficile spores of PCR ribotypes 010, 014 and 027

    NARCIS (Netherlands)

    Kenters, N.; E. Huijskens (Elisabeth); de Wit, S.C.J.; Sanders, I.G.J.M.; J.M. van Rosmalen (Joost); E. Kuijper; Voss, A.

    2017-01-01

    textabstractBackground: In healthcare facilities, Clostridium difficile infections spread by transmission of bacterial spores. Appropriate sporicidal disinfectants are needed to prevent development of clusters and outbreaks. In this study different cleaning/disinfecting wipes and sprays were tested

  7. Comparing peracetic acid and hypochlorite for disinfection of combined sewer overflows: Effects of suspended-solids and pH.

    Science.gov (United States)

    McFadden, M; Loconsole, J; Schockling, A J; Nerenberg, R; Pavissich, J P

    2017-12-01

    Peracetic acid (PAA) is an alternative disinfectant that may be effective for combined sewer overflow (CSO) disinfection, but little is known about the effect of particle size on PAA disinfection efficiency. In this work, PAA and hypochlorite were compared as disinfectants, with a focus on the effect of wastewater particles. Inactivation experiments were conducted on suspended cultures of Escherichia coli and wastewater suspended solids. Tested size fractions included particle diameters disinfection efficiency decreased with increasing solids size. However, solids size had little effect on PAA disinfection. The PAA disinfection efficiency decreased at pH values above 7.5. Live/dead staining revealed that PAA disinfection leaves most cells in a viable but non-culturable condition. Fourier transform infrared spectroscopy (FTIR) analyses suggests that PAA and hypochlorite may inactivate E. coli bacteria by similar mechanisms. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. The efficacy of potassium ferrate as a chemical disinfectant on E. coli, Vibrio cholera, human adenovirus, and Giardia lamblia

    Science.gov (United States)

    Introduction: Drinking water and wastewater go through numerous treatments to remove microorganisms and other contaminants one of many processes along the treatment train is disinfection. There are different ways to disinfect these waters, however to date the most common disinf...

  9. The efficacy of potassium ferrate as a chemical disinfectant on E. coli, Vibrio cholera, human adenovirus, and Giardia lamblia - Abstract

    Science.gov (United States)

    Introduction: Drinking water and wastewater effluents go through numerous treatments to remove microorganisms and other contaminants in the United States. One of many processes along the treatment train is disinfection, and to date the most common disinfectants still remain chemi...

  10. Poorly processed reusable surface disinfection tissue dispensers may be a source of infection.

    Science.gov (United States)

    Kampf, Günter; Degenhardt, Stina; Lackner, Sibylle; Jesse, Katrin; von Baum, Heike; Ostermeyer, Christiane

    2014-01-21

    Reusable surface disinfectant tissue dispensers are used in hospitals in many countries because they allow immediate access to pre-soaked tissues for targeted surface decontamination. On the other hand disinfectant solutions with some active ingredients may get contaminated and cause outbreaks. We determined the frequency of contaminated surface disinfectant solutions in reusable dispensers and the ability of isolates to multiply in different formulations. Reusable tissue dispensers with different surface disinfectants were randomly collected from healthcare facilities. Solutions were investigated for bacterial contamination. The efficacy of two surface disinfectants was determined in suspension tests against two isolated species directly from a contaminated solution or after 5 passages without selection pressure in triplicate. Freshly prepared use solutions were contaminated to determine survival of isolates. 66 dispensers containing disinfectant solutions with surface-active ingredients were collected in 15 healthcare facilities. 28 dispensers from nine healthcare facilities were contaminated with approximately 107 cells per mL of Achromobacter species 3 (9 hospitals), Achromobacter xylosoxidans or Serratia marcescens (1 hospital each). In none of the hospitals dispenser processing had been adequately performed. Isolates regained susceptibility to the disinfectants after five passages without selection pressure but were still able to multiply in different formulations from different manufacturers at room temperature within 7 days. Neglecting adequate processing of surface disinfectant dispensers has contributed to frequent and heavy contamination of use-solutions based on surface active ingredients. Tissue dispenser processing should be taken seriously in clinical practice.

  11. Photocatalytic disinfection of spoilage bacteria Pseudomonas fluorescens and Macrococcus caseolyticus by nano-TiO2

    Science.gov (United States)

    Photocatalytic disinfection of spoilage bacteria gram-negative (G-) P. fluorescens and gram-positive (G+) M. caseolyticus by nano-TiO2 under different experimental conditions and the disinfection mechanism were investigated. The experimental conditions included the initial bacterial populations, nan...

  12. Irradiation as an alternative for disinfection of domestic waste in the Canadian Arctic

    International Nuclear Information System (INIS)

    1981-01-01

    This study evaluated the technical and economic feasibility of various methods for disinfecting wastewater in the Canadian Arctic with specific reference to gamma radiation. More conventional disinfection practices, such as chlorination, chlorination-dechlorination, and ozonation were compared to gamma radiation along with ultraviolet irradiation and lime disinfection. The quality of lagoon effluent, highly diluted (weak) sewage, holding tank wastes and honey-bag wastes, which are the typical waste types found in northern communities, was established from data available in the literature. Further literature reviews were undertaken to establish a data base for design and effectiveness of disinfection systems operated in cold climates. Capital and operating costs for all technically feasible disinfection process alternates were estimated based on historical cost data adjusted to 1977 for the construction and instalation of similar systems in the north. The costs of equipment, chemicals, fuel and electrical power were obtained from suppliers. The environmental impact of each of the disinfection processes was reviewed with emphasis on gamma irradiation. Safety and health aspects were also considered. The study concluded that gamma irradiation was capable of providing safe, reliable disinfection for concentrated honey-bag and holding wastes. Pilot-scale testing was recommended prior to construction of full-scale disinfection facilities. For lagoon effluents and weak sewage, gamma irradiation was not cost competitive with other alternates; rather chlorination-dechlorination was found to be the most cost-effective and environmentally acceptable alternative

  13. Fungicidal effect of 15 disinfectants against 24 fungal contaminants commonly found in bread and cheese manufacturing

    DEFF Research Database (Denmark)

    Bundgaard-Nielsen, Kirsten; Nielsen, Per Væggemose

    1996-01-01

    Resistance of 19 mold- and 6 yeast- species against 15 commercial disinfectants was investigated by a suspension-method in which the fungicidal effect and germination time were determined at 20 °C. Disinfectants containing 0.5 % dodecyldiethylentriaminacetic acid, 10 g/l chloramine-T, 2.0 % forma...

  14. Determining Exposure Factors of Anti-Fogging, Dye, Disinfectant, Repellent, and Preservative Products in Korea.

    Science.gov (United States)

    Lee, Daeyeop; Kim, Joo-Hyon; Kim, Taksoo; Yoon, Hyojung; Jo, Areum; Lee, Byeongwoo; Lim, Hyunwoo; Kim, Pilje; Seo, Jungkwan

    2018-01-30

    Reliable exposure factors are essential to determine health risks posed by chemicals in consumer products. We analyzed five risk-concerned product categories (anti-fogging, dye, disinfectant, repellent, and preservative products) for 13 products (three car anti-fogging products, a lens anti-fogging product, two car dye products, two drain disinfectants, an air conditioner disinfectant, a chlorine-based disinfectant, a fabric repellent, an insect repellent for food, and a wood preservative) considered to be of high risk in order to determine exposure factors via web surveys and estimation of amount of product. Among the 3000 participants (1482 (49%) men) aged ≥19 years, drain disinfectants were used most frequently (38.2%); the rate of usage of the other products ranged between 1.1-24.0%. The usage rates for the consumer products differed by sex, age, income, and education. Some consumer products such as car and lens anti-fogging products, chlorine-based disinfectants, fabric repellents, and drain disinfectants were regularly used more than once a month, while car dye products, air conditioner disinfectants, insect repellents for food, and wood preservatives were not regularly used owing to the specific product purposes and seasonal needs. Our results could be used for managing or controlling chemical substances in consumer products and conducting accurate exposure assessments.

  15. Chloraminated Concentrated Drinking Water for Disinfection Byproduct Mixtures Research: Evaluating Free Chlorine Contact Times

    Science.gov (United States)

    Complex mixtures of disinfection by-products (DBPs) are formed when the disinfectant oxidizes constituents (e.g., natural organic matter (NOM) and organic pollutants) present in the source water. Since 1974, over 600 DBPs have been identified in drinking water, yet a large portio...

  16. Chloramination of Concentrated Drinking Water for Disinfection Byproduct Mixtures Creation- Indianapolis

    Science.gov (United States)

    Complex mixtures of disinfection by-products (DBPs) are formed when the disinfectant oxidizes constituents (e.g., natural organic matter (NOM) and organic pollutants) found in the source water. Since 1974, over 600 DBPs have been identified in drinking water. Despite intense iden...

  17. Chloramination of Concentrated Drinking Water: Evaluation of Disinfection Byproduct Formation and Dosing Scenarios - Portland

    Science.gov (United States)

    Complex mixtures of disinfection by-products (DBPs) are formed when the disinfectant oxidizes constituents (e.g., natural organic matter (NOM) and organic pollutants) found in the source water. Since 1974, over 600 DBPs have been identified in drinking water. Despite intense iden...

  18. Innovative Approach to Validation of Ultraviolet (UV) Reactors for Disinfection in Drinking Water Systems - presentation

    Science.gov (United States)

    UV disinfection is an effective process for inactivating many microbial pathogens found in source waters with the potential as stand-alone treatment or in combination with other disinfectants. For surface and groundwater sourced drinking water applications, the U.S. Environmental...

  19. Two-Center Evaluation of Disinfectant Efficacy against Ebola Virus in Clinical and Laboratory Matrices

    Science.gov (United States)

    Smither, Sophie J.; Eastaugh, Lin; Filone, Claire Marie; Freeburger, Denise; Herzog, Artemas; Lever, M. Stephen; Miller, David M.; Mitzel, Dana; Noah, James W.; Reddick-Elick, Mary S.; Reese, Amy; Schuit, Michael; Wlazlowski, Carly B.; Hevey, Michael

    2018-01-01

    Ebola virus (EBOV) in body fluids poses risk for virus transmission. However, there are limited experimental data for such matrices on the disinfectant efficacy against EBOV. We evaluated the effectiveness of disinfectants against EBOV in blood on surfaces. Only 5% peracetic acid consistently reduced EBOV titers in dried blood to the assay limit of quantification. PMID:29261093

  20. Comparing Peracetic Acid with Sodium Hypochlorite for Disinfection of Combined Sewer Overflows

    Science.gov (United States)

    This cooperative research and development agreement between U.S. EPA, Solvay, MSDGC, and CB&I is evaluating the potential of PAA for disinfection of Muddy Creek CSO wastewater and comparing that with sodium hypochlorite disinfection. This presentation will document the effective...

  1. Bench-Scale Evaluation of Peracetic Acid and Twin Oxide ™ as Disinfectants in Drinking Water

    Science.gov (United States)

    Chlorine is widely used as an inexpensive and potent disinfectant in the United States for drinking water. However, chlorine has the potential for forming carcinogenic and mutagenic disinfection by-products (DBPs). In this study, bench scale experiments were conducted at the U.S...

  2. High-Rate Disinfection Techniques for Combined Sewer Overflow (Proceedings Paper)

    Science.gov (United States)

    This paper presents high-rate disinfection technologies for combined sewer overflow (CSO). The high-rate disinfection technologies of interest are: chlorination/dechlorination, ultraviolet light irradiation (UV), chlorine dioxide (ClO2 ), ozone (O3), peracetic acid (CH3COOOH ), a...

  3. Experience of using heat citric acid disinfection method in central dialysis fluid delivery system.

    Science.gov (United States)

    Sakuma, Koji; Uchiumi, Nobuko; Sato, Sumihiko; Aida, Nobuhiko; Ishimatsu, Taketo; Igoshi, Tadaaki; Kodama, Yoshihiro; Hotta, Hiroyuki

    2010-09-01

    We applied the heat citric acid disinfection method in the main part of the central dialysis fluid delivery system (MPCDDS), which consists of a multiple-patient dialysis fluid supply unit, dialysis console units, and dialysis fluid piping. This disinfection method has been used for single-patient dialysis machines, but this is the first trial in the MPCDDS. We examined, by points of safety and disinfection effect, whether this disinfection method is comparable to conventional disinfection methods in Japan. The conventional disinfection method is a combination of two disinfectants, sodium hypochlorite and acetic acid, used separately for protein removal and decalcification. Consequently, total microbial counts and endotoxin concentrations fully satisfied the microbiological requirements for standard dialysis fluid of ISO 11663. From our results and discussion, this heat citric acid disinfection method is proved to be safe and reliable for MPCDDS. However, to satisfy the microbiological requirements for ultrapure dialysis fluid, further consideration for this method in MPCDDS including the reverse osmosis device composition and piping is necessary.

  4. Comparative transcriptome and phenotype analysis of Bacillus cereus in response to disinfectant treatments

    NARCIS (Netherlands)

    Ceragioli, Mara; Mols, J.M.; Moezelaar, Roy; Ghelardi, Emilia; Senesi, Sonia; Abee, Tjakko

    2010-01-01

    Antimicrobial chemicals are widely applied to clean and disinfect food-contacting surfaces. However, the cellular response of bacteria, such as Bacillus cereus, to various disinfectants is unclear. In this study, the physiological and genome-wide transcriptional responses of B. cereus ATCC 14579

  5. Comparative transcriptomic and phenotypic analysis of the responses of Bacillus cereus to various disinfectant treatments

    NARCIS (Netherlands)

    Ceragioli, M.; Mols, J.M.; Moezelaar, R.; Ghelardi, E.; Senesi, S.; Abee, T.

    2010-01-01

    Antimicrobial chemicals are widely applied to clean and disinfect food-contacting surfaces. However, the cellular response of bacteria to various disinfectants is unclear. In this study, the physiological and genome-wide transcriptional responses of Bacillus cereus ATCC 14579 exposed to four

  6. A microbiological evaluation of level of disinfection for flexible cystoscopes protected by disposable endosheaths

    DEFF Research Database (Denmark)

    Jørgensen, Peter Hjorth; Slotsbjerg, Torsten; Westh, Henrik

    2013-01-01

    Flexible cystoscopy is used in urological outpatient departments for diagnostic cystoscopy of bladder cancer and requires a high-level disinfection between each patient. The purpose of this study was to make a microbiological post disinfection efficacy assessment of flexible cystoscopes (FC) using...

  7. Industrial disinfectants do not select for resistance in Listeria monocytogenes following long term exposure

    DEFF Research Database (Denmark)

    Kastbjerg, Vicky Gaedt; Gram, Lone

    2012-01-01

    or tolerance would evolve in L. monocytogenes under continued selection in three industrial disinfectants. L. monocytogenes EGD was exposed to Desinfect CL (hypochlorite) and Incimaxx DES (peracedic acid and hydrogen peroxide) for several hundred generations. This caused no increase in the minimal inhibitory......, and that the disinfectants are still efficient for controlling microorganisms such as L. monocytogenes....

  8. Development of a Standard Test to Assess the Resistance of Staphylococcus aureus Biofilm Cells to Disinfectants

    NARCIS (Netherlands)

    Luppens, S.B.I.; Reij, M.W.; Heijden, van der R.W.; Rombouts, F.M.; Abee, T.

    2002-01-01

    A standardized disinfectant test for Staphylococcus aureus cells in biofilms was developed. Two disinfectants, the membrane-active compound benzalkonium chloride (BAC) and the oxidizing agent sodium hypochlorite, were used to evaluate the biofilm test. S. aureus formed biofilms on glass, stainless

  9. CONTROL OF MICROBIAL CONTAMINANTS AND DISINFECTION BY-PRODUCTS (DBPS): COST AND PERFORMANCE

    Science.gov (United States)

    The USEPA is in the process of developing a sophisticated regulatory strategy in an attempt to balance the complex trade-offs in risks associated with controlling disinfectants and disinfection by-products (D/DBPs) in drinking water. EPA first attempted to control DBPs in 1974, w...

  10. 76 FR 39092 - Agency Information Collection Activities; Proposed Collection; Comment Request; Disinfectants...

    Science.gov (United States)

    2011-07-05

    ... Office of Management and Budget (OMB). The ICRs scheduled to expire are Disinfectants/Disinfection...) enhance the quality, utility, and clarity of the information to be collected; and (iv) minimize the burden...-community water systems such as restaurants and campgrounds. What should I consider when I prepare my...

  11. Reducing viral contamination from finger pads: handwashing is more effective than alcohol-based hand disinfectants

    NARCIS (Netherlands)

    Tuladhar, E.; Hazeleger, W.C.; Koopmans, M.; Zwietering, M.H.; Duizer, E.

    2015-01-01

    Background - Hand hygiene is important for interrupting transmission of viruses through hands. Effectiveness of alcohol-based hand disinfectant has been shown for bacteria but their effectiveness in reducing transmission of viruses is ambiguous. Aim - To test efficacy of alcohol hand disinfectant

  12. 9 CFR 71.12 - Sodium orthophenylphenate as permitted disinfectant for premises infected with tuberculosis.

    Science.gov (United States)

    2010-01-01

    ... disinfectant for premises infected with tuberculosis. 71.12 Section 71.12 Animals and Animal Products ANIMAL... disinfectant for premises infected with tuberculosis. (a) A permitted brand of sodium orthophenylphenate in a proportion of at least one pound to 12 gallons of water is permitted in tuberculosis eradication work for...

  13. Does improving surface cleaning and disinfection reduce health care-associated infections?

    Science.gov (United States)

    Donskey, Curtis J

    2013-05-01

    Contaminated environmental surfaces provide an important potential source for transmission of health care-associated pathogens. In recent years, a variety of interventions have been shown to be effective in improving cleaning and disinfection of surfaces. This review examines the evidence that improving environmental disinfection can reduce health care-associated infections. Published by Mosby, Inc.

  14. Evaluation of 5 cleaning and disinfection methods for nets used to collect zebrafish (Danio rerio).

    Science.gov (United States)

    Collymore, Chereen; Porelli, Gina; Lieggi, Christine; Lipman, Neil S

    2014-11-01

    Few standardized methods of cleaning and disinfecting equipment in zebrafish facilities have been published, even though the effectiveness of these procedures is vital to preventing the transmission of pathogenic organisms. Four chemical disinfectants and rinsing with municipal tap water were evaluated for their ability to disinfect nets used to capture zebrafish. The disinfectants included benzalkonium chloride+methylene blue, sodium hypochlorite, chlorine dioxide, and potassium peroxymonosulfate+sodium chloride for a soak time of 5 or 30 min. Disinfection effectiveness was evaluated by using an ATP-based system that measured the reduction in absolute number and percentage of relative light units. In addition, nets were cultured aerobically on blood and MacConkey agar plates to determine the number of bacteria remaining after disinfection procedures. Soaking nets in sodium hypochlorite for 30 min and in potassium peroxymonosulfate+sodium chloride for 5 or 30 min were effective means of disinfection, according to at least 90% reduction in the number of relative light units and no bacterial growth after cleaning. These results will aid facility managers, veterinarians and investigators in selecting net cleaning and disinfection protocols.

  15. Endoscope disinfection and its pitfalls--requirement for retrograde surveillance cultures.

    NARCIS (Netherlands)

    Buss, A.J.; Been, M.H.; Borgers, R.P.; Stokroos, I.; Melchers, W.J.G.; Peters, F.T.; Limburg, A.J.; Degener, J.E.

    2008-01-01

    BACKGROUND AND STUDY AIMS: Several endoscopy-related outbreaks of infection have been reported in recent years. For early recognition of inadequate disinfection of endoscopes we designed a microbiological surveillance system to evaluate the efficacy of the cleaning and disinfection procedure, and to

  16. Some factors influencing the effective use of disinfectants and cleaning agents

    Directory of Open Access Journals (Sweden)

    W.P. Kortenbout

    1982-09-01

    Full Text Available Disinfection means the freeing of an article from some or all of its burden of live pathogenic microorganisms which might cause infection during its use. The term is a relative one and disinfection may be described as being partially or highly effective according to the proportion of pathogenic organisms killed or removed.

  17. Microbial quality of swimming pool water with treatment without disinfection, with ultrafiltration, with UV-based treatment and with chlorination

    NARCIS (Netherlands)

    Keuten, M.G.A.; Peters, M.C.F.M.; van Dijk, J.C.; van Loosdrecht, Mark C.M.; Rietveld, L.C.

    2017-01-01

    Swimming pools are traditionally disinfected with a residual disinfectant such as sodium hypochlorite. Nowadays, swimming water without a residual disinfectant is increasingly popular, as can be seen by the growing number of (natural) swimming ponds (Weilandt 2015), but health risks for bathers do

  18. 9 CFR 309.7 - Livestock affected with anthrax; cleaning and disinfection of infected livestock pens and driveways.

    Science.gov (United States)

    2010-01-01

    ...; cleaning and disinfection of infected livestock pens and driveways. 309.7 Section 309.7 Animals and Animal... INSPECTION § 309.7 Livestock affected with anthrax; cleaning and disinfection of infected livestock pens and... followed immediately by a thorough disinfection of the exposed premises by soaking the ground, fences...

  19. Comparison of electrochemical method with ozonation, chlorination and monochloramination in drinking water disinfection

    Energy Technology Data Exchange (ETDEWEB)

    Li Hongna, E-mail: lihongna@gmail.com [Department of Environmental Engineering, Peking University, Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing 100871 (China); Zhu Xiuping [Department of Environmental Engineering, Peking University, Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing 100871 (China); Ni Jinren, E-mail: nijinren@iee.pku.edu.cn [Department of Environmental Engineering, Peking University, Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing 100871 (China)

    2011-11-30

    Highlights: > Electrochemical, O{sub 3}, NaClO and NH{sub 2}Cl were compared at respective optimal condition. > Disinfection efficacy was similar for different bacteria in electrolysis. > Harsh Bacillus was inactivated more difficult in O{sub 3}, NaClO and NH{sub 2}Cl system. > Efficient disinfection of electrolysis was attributed to nonselectivity of {center_dot}OH. > Cell surface damage was more obvious in electrochemical process than the others. - Abstract: Electrochemical process in chloride-free electrolytes was proved to be powerful in disinfection due to the strong oxidants produced in the electrolysis and no formation of disinfection byproducts (DBPs). In this study, disinfection experiments were conducted by electrochemical treatment compared with ordinary and advanced methods (ozonation, chlorination and monochloramination), with Escherichia coli (E. coli) K-12, Staphylococcus aureus (S. aureus) A106, Bacillus subtilis (BST) and an isolated Bacillus as the representative microorganisms. Firstly, factor tests were performed on E. coli to obtain the optimal conditions of the four disinfection procedures. At their respective optimal condition, CT (concentration of disinfectant x contact time) value of a 4-log E. coli inactivation was 33.5, 1440, 1575, 1674 mg min L{sup -1} for electrochemical process, ozonation, chlorination and monochloramination, respectively. It was demonstrated that the disinfection availability was in the following order: electrochemical process > ozonation > chlorination > monochloramination, which could be attributed to the hydroxyl radical generated in the electrolysis, with strong oxidizing ability and non-selectivity compared with the other three disinfectants. Moreover, the disinfection efficacy of the four disinfection procedures was compared for four different bacteria. It was found that the disinfection efficacy was similar for the selected four bacteria in electrochemical process, while in the other three treatments

  20. Comparison of electrochemical method with ozonation, chlorination and monochloramination in drinking water disinfection

    International Nuclear Information System (INIS)

    Li Hongna; Zhu Xiuping; Ni Jinren

    2011-01-01

    Highlights: → Electrochemical, O 3 , NaClO and NH 2 Cl were compared at respective optimal condition. → Disinfection efficacy was similar for different bacteria in electrolysis. → Harsh Bacillus was inactivated more difficult in O 3 , NaClO and NH 2 Cl system. → Efficient disinfection of electrolysis was attributed to nonselectivity of ·OH. → Cell surface damage was more obvious in electrochemical process than the others. - Abstract: Electrochemical process in chloride-free electrolytes was proved to be powerful in disinfection due to the strong oxidants produced in the electrolysis and no formation of disinfection byproducts (DBPs). In this study, disinfection experiments were conducted by electrochemical treatment compared with ordinary and advanced methods (ozonation, chlorination and monochloramination), with Escherichia coli (E. coli) K-12, Staphylococcus aureus (S. aureus) A106, Bacillus subtilis (BST) and an isolated Bacillus as the representative microorganisms. Firstly, factor tests were performed on E. coli to obtain the optimal conditions of the four disinfection procedures. At their respective optimal condition, CT (concentration of disinfectant x contact time) value of a 4-log E. coli inactivation was 33.5, 1440, 1575, 1674 mg min L -1 for electrochemical process, ozonation, chlorination and monochloramination, respectively. It was demonstrated that the disinfection availability was in the following order: electrochemical process > ozonation > chlorination > monochloramination, which could be attributed to the hydroxyl radical generated in the electrolysis, with strong oxidizing ability and non-selectivity compared with the other three disinfectants. Moreover, the disinfection efficacy of the four disinfection procedures was compared for four different bacteria. It was found that the disinfection efficacy was similar for the selected four bacteria in electrochemical process, while in the other three treatments inactivation of the two

  1. Peracetic acid disinfection: a feasible alternative to wastewater chlorination.

    Science.gov (United States)

    Rossi, S; Antonelli, M; Mezzanotte, V; Nurizzo, C

    2007-04-01

    The paper summarizes the results of a bench-scale study to evaluate the feasibility of using peracetic acid (PAA) as a substitute for sodium hypochlorite both for discharge into surface water and for agricultural reuse. Trials were carried out with increasing doses (1, 2, 3, 5, 10, and 15 mg/L) and contact times (6, 12, 18, 36, 42, and 54 minutes) to study disinfectant decay and bacterial removal and regrowth, using fecal coliform and Escherichia coli (E. coli) as process efficiency indicators. Peracetic acid decay kinetics was evaluated in tap water and wastewater; in both cases, PAA decays according to first-order kinetics with respect to time, and a correlation was found between PAA oxidative initial consumption and wastewater characteristics. The PAA disinfection efficiency was correlated with operating parameters (active concentration and contact time), testing different kinetic models. Two data groups displaying a different behavior on the basis of initial active concentration ranges (1 to 2 mg/L and 5 to 15 mg/L, respectively) can be outlined. Both groups had a "tailing-off" inactivation curve with respect to time, but the second one showed a greater inactivation rate. Moreover, the effect of contact time was greater at the lower doses. Hom's model, used separately for the two data groups, was found to best fit experimental data, and the disinfectant active concentration appears to be the main factor affecting log-survival ratios. Moreover, the S-model better explains the initial resistance of E. coli, especially at low active concentrations (< 2 mg/L) and short contact times (< 12 minutes). Microbial counts, performed by both traditional methods and flow cytometry, immediately and 5 hours after sample collection (both with or without residual PAA inactivation), showed that no appreciable regrowth took place after 5 hours, neither for coliform group bacteria, nor for total heterotrophic bacteria.

  2. Enhancing blood donor skin disinfection using natural oils.

    Science.gov (United States)

    Alabdullatif, Meshari; Boujezza, Imen; Mekni, Mohamed; Taha, Mariam; Kumaran, Dilini; Yi, Qi-Long; Landoulsi, Ahmed; Ramirez-Arcos, Sandra

    2017-12-01

    Effective donor skin disinfection is essential in preventing bacterial contamination of blood components with skin flora bacteria like Staphylococcus epidermidis. Cell aggregates of S. epidermidis (biofilms) are found on the skin and are resistant to the commonly used donor skin disinfectants chlorhexidine-gluconate and isopropyl alcohol. It has been demonstrated that essential oils synergistically enhance the antibacterial activity of chlorhexidine-gluconate. The objective of this study was to test plant-extracted essential oils in combination with chlorhexidine-gluconate or chlorhexidine-gluconate plus isopropyl alcohol for their ability to eliminate S. epidermidis biofilms. The composition of oils extracted from Artemisia herba-alba, Lavandula multifida, Origanum marjoram, Rosmarinus officinalis, and Thymus capitatus was analyzed using gas chromatography-mass spectrometry. A rabbit model was used to assess skin irritation caused by the oils. In addition, the anti-biofilm activity of the oils used alone or in combination with chlorhexidine-gluconate or chlorhexidine-gluconate plus isopropyl alcohol was tested against S. epidermidis biofilms. Essential oil concentrations 10%, 20%, and 30% were chosen for anti-biofilm assays, because skin irritation was observed at concentrations greater than 30%. All oils except for O. marjoram had anti-biofilm activity at these three concentrations. L. multifida synergistically enhanced the anti-biofilm activity of chlorhexidine-gluconate and resulted in the highest anti-biofilm activity observed when combined with chlorhexidine-gluconate plus isopropyl alcohol. Gas chromatography-mass spectrometry revealed that the main component contributing to the activity of L. multifida oil was a natural terpene alcohol called linalool. The anti-biofilm activity of chlorhexidine-gluconate plus isopropyl alcohol can be greatly enhanced by L. multifida oil or linalool. Therefore, these components could potentially be used to improve blood

  3. Activity of disinfectants and biofilm production of Corynebacterium pseudotuberculosis

    Directory of Open Access Journals (Sweden)

    Maria da C.A. Sá

    2013-11-01

    Full Text Available To verify the occurrence of caseous lymphadenitis in sheep and goats on farms of Pernambuco, Brazil, and in animals slaughtered in two Brazilian cities (Petrolina/PE and Juazeiro/BA, and to characterize the susceptibility profile of Corynebacterium pseudotuberculosis to disinfectants and antimicrobials, and its relationship with biofilm production were the objectives of this study. 398 samples were tested for sensitivity to antimicrobial drugs, disinfectants, and biofilm production. Among the 108 samples collected on the properties, 75% were positive for C. pseudotuberculosis. Slaughterhouse samples indicated an occurrence of caseous lymphadenitis in 15.66% and 6.31% for animals slaughtered in Petrolina and Juazeiro respectively. With respect to antimicrobials, the sensitivity obtained was 100% for florfenicol and tetracycline; 99.25% for enrofloxacin, ciprofloxacin and lincomycin; 98.99% for cephalothin; 98.74% for norfloxacin and sulfazotrim; 97.74% for gentamicin; 94.22% for ampicillin; 91.71% for amoxicillin; 91.21% for penicillin G; 89.19% for neomycin and 0% for novobiocin. In analyzes with disinfectants, the efficiency for chlorhexidine was 100%, 97.20% for quaternary ammonium, 87.40% for chlorine and 84.40% for iodine. 75% of the isolates were weak or non-biofilm producers. For the consolidated biofilm, found that iodine decreased biofilm formation in 13 isolates and quaternary ammonia in 11 isolates. The reduction of the biofilm formation was observed for iodine and quaternary ammonium in consolidated biofilm formation in 33% and 28% of the isolates, respectively. The results of this study highlight the importance of establishing measures to prevent and control the disease.

  4. Is pomegranate peels infusion effective for disinfection of toothbrushes?

    Directory of Open Access Journals (Sweden)

    Priscila Lima de Luna FREIRE

    Full Text Available Abstract Introduction Methods of decontamination or sanitization of toothbrushes have been questioned. Objective This study assessed the effectiveness of pomegranate peels infusion as a disinfectant of toothbrushes against Streptococcus mutans. Material and method A sample of 16 schoolchildren aged between 7 and 9 years performed brushing 5 days/week, with a careful brushing once a day. After each day of brushing, the toothbrushes were washed and sprayed with one disinfectant solution. This procedure was repeated for 4 weeks using one of the different solutions per week: distilled water (G1; negative control, pomegranate (Punica granatum Linn peels infusion (G2, 1% sodium hypochlorite (G3 and 0.12% chlorhexidine digluconate (G4. After the fifth day, toothbrushes were collected for laboratory analysis. Toothbrushes heads were subjected to agitation in saline dilution of 10–1, 10–2,10–3, and 25 μL of each dilution were seeded in mitis salivarius agar culture medium for S. mutans colony-forming unit (CFU counting. One calibrated examiner (Kappa = 0.91 performed the CFU (mL–1 × 104 counts. Kruskal-Wallis and Dunn Multiple Comparison tests were used at a significance level of 5%. Result G1 presented the highest number of CFU (3.9 ± 8.4, followed by G2 (3.2 ± 4.0. No S. mutans growth was observed in G3 and G4. There was no statistically significant difference between G1 and G2 and between G3 and G4 (p>0.05. Conclusion Pomegranate infusion was completely ineffective for the disinfection of toothbrushes against S. mutans when compared with 1% sodium hypochlorite and 0.12% chlorhexidine digluconate solutions.

  5. Efficacy and toxicity of iodine disinfection of Atlantic salmon eggs

    Science.gov (United States)

    Chalupnicki, M.A.; Ketola, H.G.; Starliper, C.E.; Gallagher, D.

    2011-01-01

    Recent interest in the restoration of Atlantic salmon Salmo salar in the Great Lakes has given rise to new culture techniques and management programs designed to reduce pathogen transmission while stabilizing and enhancing wild populations. We examined the toxicity of iodine to Atlantic salmon eggs and its effectiveness as a disinfectant against bacteria on egg surfaces. We spawned and fertilized eight gravid Atlantic salmon from Cayuga Lake, New York, and exposed their eggs to 10 concentrations of iodine (5, 10, 50, 75, 100, 500, 750, 1,000, 5,000, and 7,500 mg/L) for 30 min during water hardening. An additional subsample of unfertilized eggs was also exposed to some of the same concentrations of iodine (5, 10, 50, 75, and 100 mg/L) to determine the efficiency of disinfection. Viable eggs were only obtained from four females. Survival of eggs to the eyed stage and hatch tended to be reduced at iodine concentrations of 50 and 75 mg/L and was significantly reduced at concentrations of 100 mg/L iodine or more. We calculated the concentrations of iodine that killed 50% of the Atlantic salmon eggs at eye-up and hatch to be 175 and 85 mg/L, respectively. Aeromonas veronii, A. schubertii, A. hydrophila, A. caviae, Plesiomonas shiggeloides, and Citrobacter spp. were the predominant bacteria present on the surface of green eggs and were significantly reduced by an iodine immersion. The use of iodine as a disinfectant on Atlantic salmon eggs was effective at low concentrations (50–75 mg/L), for which toxicity to Atlantic salmon was minimal.

  6. [Surface disinfection in the context of infection prevention in intensive care units].

    Science.gov (United States)

    Kossow, A; Schaber, S; Kipp, F

    2013-03-01

    The highest proportion of nosocomial infections occurs on intensive care units (ICU) and infections with multiresistant pathogens are an ever increasing problem. Preventative measures should consist of a bundle of different measures including measures that address a specific problem and standard hygiene measures that are relevant in all areas. Specific measures in ICUs primarily aim at the prevention of ventilator associated pneumonia, blood vessel catheter associated infections and nosocomial urinary tract infections. Surface disinfection belongs to the standard hygiene measures and plays an inferior role compared to hand hygiene; however, surfaces come into focus in outbreak situations. The Commission on Hospital Hygiene (KRINKO) at the Robert Koch Institute (the German health protection agency) published recommendations regarding the cleaning and disinfection of surfaces. The frequency with which cleaning and/or disinfection is required varies according to defined areas of risk. The frequency and the disinfection agents used are documented in the disinfection plan.

  7. Impact of egg disinfection of hatching eggs on the eggshell microbiome and bacterial load

    DEFF Research Database (Denmark)

    Olsen, R.; Kudirkiene, E.; Thofner, I.

    2017-01-01

    Disinfection of hatching eggs is essential to ensure high quality production of broilers. Different protocols are followed in different hatcheries; however, only limited scientific evidence on how the disinfection procedures impact the microbiome is available. The aim of the present study...... was to characterize the microbiome and aerobic bacterial load of hatching eggs before disinfection and during the subsequent disinfection steps. The study included a group of visibly clean and a group of visibly dirty eggs. For dirty eggs, an initial wash in chlorine was performed, hereafter all eggs were submitted...... to two times fumigation and finally spray disinfection. The eggshell microbiome was characterized by sequencing of the total amount of 16S rRNA extracted from each sample, consisting of shell surface swabs of five eggs from the same group. In addition, the number of colony forming units (cfu) under...

  8. Peracetic acid in the disinfection of a hospital water system contaminated with Legionella species.

    Science.gov (United States)

    Ditommaso, Savina; Biasin, Cinzia; Giacomuzzi, Monica; Zotti, Carla Maria; Cavanna, Alberto; Ruggenini Moiraghi, Angela

    2005-05-01

    To assess the efficacy of an alternative disinfection method for hospital water distribution systems contaminated with Legionella. Disinfection with peracetic acid was performed in a small hospital contaminated with L. pneumophila serotype 1. The disinfectant was used at concentrations of 50 ppm (first three surveillance phases) and 1,000 ppm (fourth surveillance phase) for 30 minutes. Environmental monitoring revealed that disinfection was maintained 1 week after treatment; however, levels of recontamination surpassing baseline values were detected after approximately 1 month. Comparison of water temperatures measured at the distal outlets showed a statistically significant association between temperature and bacterial load. The circulating water temperature was found to be lower in the two wards farthest away from the hot water production plant than in other wards. It was thought that the lower water temperature in the two wards promoted the bacterial growth even after disinfection. Peracetic acid may be useful in emergency situations, but does not provide definitive protection even if used monthly.

  9. Resistance of Pseudomonas aeruginosa to liquid disinfectants on contaminated surfaces before formation of biofilms.

    Science.gov (United States)

    Sagripanti, J L; Bonifacino, A

    2000-01-01

    A comparison was made of the effectiveness of popular disinfectants (Cavicide, Cidexplus, Clorox, Exspor, Lysol, Renalin, and Wavicide) under conditions prescribed for disinfection in the respective product labels on Pseudomonas aeruginosa either in suspension or deposited onto surfaces of metallic or polymeric plastic devices. The testing also included 7 nonformulated germicidal agents (glutaraldehyde, formaldehyde, peracetic acid, hydrogen peroxide, sodium hypochlorite, phenol, and cupric ascorbate) commonly used in disinfection and decontamination. Results showed that P. aeruginosa is on average 300-fold more resistant when present on contaminated surfaces than in suspension. This increase in resistance agrees with results reported in studies of biofilms, but unexpectedly, it precedes biofilm formation. The surface to which bacteria are attached can influence the effectiveness of disinfectants. Viable bacteria attached to devices may require dislodging through more than a one-step method for detection. The data, obtained with a sensitive and quantitative test, suggest that disinfectants are less effective on contaminated surfaces than generally acknowledged.

  10. Chemical disinfection of combined sewer overflow waters using performic acid or peracetic acids

    DEFF Research Database (Denmark)

    Chhetri, Ravi Kumar; Thornberg, Dines; Berner, Jesper

    2014-01-01

    We investigated the possibility of applying performic acid (PFA) and peracetic acid (PAA) for disinfection of combined sewer overflow (CSO) in existing CSO management infrastructures. The disinfection power of PFA and PAA towards Escherichia coli (E. coli) and Enterococcus was studied in batch......-scale and pre-field experiments. In the batch-scale experiment, 2.5 mg L− 1 PAA removed approximately 4 log unit of E. coli and Enterococcus from CSO with a 360 min contact time. The removal of E. coli and Enterococcus from CSO was always around or above 3 log units using 2–4 mg L− 1 PFA; with a 20 min contact...... time in both batch-scale and pre-field experiments. There was no toxicological effect measured by Vibrio fischeri when CSO was disinfected with PFA; a slight toxic effect was observed on CSO disinfected with PAA. When the design for PFA based disinfection was applied to CSO collected from an authentic...

  11. Effectiveness of disinfection with alcohol 70% (w/v of contaminated surfaces not previously cleaned

    Directory of Open Access Journals (Sweden)

    Maurício Uchikawa Graziano

    2013-04-01

    Full Text Available OBJECTIVE: To evaluate the disinfectant effectiveness of alcohol 70% (w/v using friction, without previous cleaning, on work surfaces, as a concurrent disinfecting procedure in Health Services. METHOD: An experimental, randomized and single-blinded laboratory study was undertaken. The samples were enamelled surfaces, intentionally contaminated with Serratia marcescens microorganisms ATCC 14756 106 CFU/mL with 10% of human saliva added, and were submitted to the procedure of disinfection WITHOUT previous cleaning. The results were compared to disinfection preceded by cleaning. RESULTS: There was a reduction of six logarithms of the initial microbial population, equal in the groups WITH and WITHOUT previous cleaning (p=0.440 and a residual microbial load ≤ 102 CFU. CONCLUSION: The research demonstrated the acceptability of the practice evaluated, bringing an important response to the area of health, in particular to Nursing, which most undertakes procedures of concurrent cleaning /disinfecting of these work surfaces.

  12. Effectiveness of disinfection with alcohol 70% (w/v of contaminated surfaces not previously cleaned

    Directory of Open Access Journals (Sweden)

    Maurício Uchikawa Graziano

    Full Text Available OBJECTIVE: To evaluate the disinfectant effectiveness of alcohol 70% (w/v using friction, without previous cleaning, on work surfaces, as a concurrent disinfecting procedure in Health Services. METHOD: An experimental, randomized and single-blinded laboratory study was undertaken. The samples were enamelled surfaces, intentionally contaminated with Serratia marcescens microorganisms ATCC 14756 106 CFU/mL with 10% of human saliva added, and were submitted to the procedure of disinfection WITHOUT previous cleaning. The results were compared to disinfection preceded by cleaning. RESULTS: There was a reduction of six logarithms of the initial microbial population, equal in the groups WITH and WITHOUT previous cleaning (p=0.440 and a residual microbial load ≤ 102 CFU. CONCLUSION: The research demonstrated the acceptability of the practice evaluated, bringing an important response to the area of health, in particular to Nursing, which most undertakes procedures of concurrent cleaning /disinfecting of these work surfaces.

  13. Ultraviolet light-emitting diodes in water disinfection.

    Science.gov (United States)

    Vilhunen, Sari; Särkkä, Heikki; Sillanpää, Mika

    2009-06-01

    The novel system of ultraviolet light-emitting diodes (UV LEDs) was studied in water disinfection. Conventional UV lamps, like mercury vapor lamp, consume much energy and are considered to be problem waste after use. UV LEDs are energy efficient and free of toxicants. This study showed the suitability of LEDs in disinfection and provided information of the effect of two emitted wavelengths and different test mediums to Escherichia coli destruction. Common laboratory strain of E. coli (K12) was used and the effects of two emitted wavelengths (269 and 276 nm) were investigated with two photolytic batch reactors both including ten LEDs. The effects of test medium were examined with ultrapure water, nutrient and water, and nutrient and water with humic acids. Efficiency of reactors was almost the same even though the one emitting higher wavelength had doubled optical power compared to the other. Therefore, the effect of wavelength was evident and the radiation emitted at 269 nm was more powerful. Also, the impact of background was studied and noticed to have only slight deteriorating effect. In the 5-min experiment, the bacterial reduction of three to four log colony-forming units (CFU) per cubic centimeter was achieved, in all cases. When turbidity of the test medium was greater, part of the UV radiation was spent on the absorption and reactions with extra substances on liquid. Humic acids can also coat the bacteria reducing the sensitivity of the cells to UV light. The lower wavelength was distinctly more efficient when the optical power is considered, even though the difference of wavelengths was small. The reason presumably is the greater absorption of DNA causing more efficient bacterial breakage. UV LEDs were efficient in E. coli destruction, even if LEDs were considered to have rather low optical power. The effect of wavelengths was noticeable but the test medium did not have much impact. This study found UV LEDs to be an optimal method for bacterial

  14. Disinfection of Biofilms in Tubes with Ultraviolet Light

    DEFF Research Database (Denmark)

    Bak, Jimmy; Begovic, Tanja

    2009-01-01

    Bacterial biofilms on long-term catheters are a major source of infection. We demonstrate here the potential of UVC light emitting diodes (LED) for disinfection purposes in catheter like tubes contaminated with biofilm. We show that UVC Light propagation is possible through teflon tubes using...... to a flow system and biofilms were produced during a three day period. Tubes in lengths of 10 cm (FEP teflon) were contaminated. Tubes for control and for UVC treatment were contaminated in parallel. The control and UVC treated tubes were both filled with a 20 % NaCl solution during the UVC treatment time...

  15. Ultraviolet radiation as disinfection for fish surgical tools

    Energy Technology Data Exchange (ETDEWEB)

    Walker, Ricardo W.; Markillie, Lye Meng; Colotelo, Alison HA; Geist, David R.; Gay, Marybeth E.; Woodley, Christa M.; Eppard, M. B.; Brown, Richard S.

    2013-04-04

    Telemetry is frequently used to examine the behavior of fish, and the transmitters used are normally surgically implanted into the coelomic cavity of fish. Implantation requires the use of surgical tools such as scalpels, forceps, needle holders, and sutures. When fish are implanted consecutively, as in large telemetry studies, it is common for surgical tools to be sterilized or, at minimum, disinfected between each use so that pathogens that may be present are not spread among fish. To determine the efficacy for this application, ultraviolet (UV) radiation was used to disinfect surgical tools exposed to one of four aquatic organisms that typically lead to negative health issues for salmonids. These organisms included Aeromonas salmonicida, Flavobacterium psychrophilum, Renibacterium salmoninarum, and Saprolegnia parasitica, causative agents of furunculosis, coldwater disease, bacterial kidney disease, and saprolegniasis (water mold), respectively. Four experiments were conducted to address the question of UV efficacy. In the first experiment, forceps were exposed to the three bacteria at three varying concentrations. After exposure to the bacterial culture, tools were placed into a mobile Millipore UV sterilization apparatus. The tools were then exposed for three different time periods – 2, 5, or 15 min. UV radiation exposures at all durations were effective at killing all three bacteria on forceps at the highest bacteria concentrations. In the second experiment, stab scalpels, sutures, and needle holders were exposed to A. salmonicida using the same methodology as used in Experiment 1. UV radiation exposure at 5 and 15 min was effective at killing A. salmonicida on stab scalpels and sutures but not needle holders. In the third experiment, S. parasitica, a water mold, was tested using an agar plate method and forceps-pinch method. UV radiation was effective at killing the water mold at all three exposure durations. Collectively, this study shows that UV

  16. Interaction between some disinfectants and Tcsup(99m)-radiopharmaceuticals

    International Nuclear Information System (INIS)

    Verbruggen, A.; Cleynhens, B.; Hoogmartens, M.; De Roo, M.

    1985-01-01

    Contamination of Tcsup(99m) sulphur colloid with small amounts of iodinated antiseptics has been described to result in the formation of free pertechnetate and excessive blood-pool activity upon injection. As far as we know similar or other interactions have not been reported for disinfectants that are effective by another mechanism than oxidizing activity. The present study has been set up to investigate the effect of small amounts of a wide variety of commonly available antiseptics on the radiochemical and biological behaviour of different Tcsup(99m) labelled radiopharmaceuticals. (Auth.)

  17. Effectiveness of Disinfectants on Antimicrobial and Physical Properties of Dental Impression Materials.

    Science.gov (United States)

    Demajo, Jean Karl; Cassar, Valter; Farrugia, Cher; Millan-Sango, David; Sammut, Charles; Valdramidis, Vasilis; Camilleri, Josette

    2016-01-01

    The aim of this study was to assess the antimicrobial activity of chemical disinfectants on alginate and silicone impression materials. The effect of chemical disinfectants on the dimensional stability of the impression materials was also assessed. For the microbiologic assessment, impressions of the maxillary arch were taken from 14 participants, 7 using alginate and 7 using an addition silicone. The impressions were divided into three sections. Each section was subjected to spraying with MD 520 or Minuten or no disinfection (control), respectively. Antimicrobial action of the chemical disinfectants was assessed by measuring microbial counts in trypticase soy agar (TSA) media and expressing the results in colony-forming units/cm2. The surface area of the dental impressions was calculated by scanning a stone cast using computer-aided design/computer-assisted manufacture and analyzing the data using a custom computer program. The dimensional stability of the impression materials after immersion in disinfectants was assessed by measuring the linear displacement of horizontally restrained materials using a traveling microscope. The percent change in length over 3 hours was thus determined. Alginate exhibited a higher microbial count than silicone. MD 520 eliminated all microbes as opposed to Minuten. The bacterial growth after Minuten disinfection was almost twice as much for alginate than for addition silicone impressions. The chemical disinfectants affected the alginate dimensional stability. Minuten reduced the shrinkage sustained by alginate during the first hour of storage. Alginate harbors three times more microorganisms than silicone impression material. Chemical disinfection by glutaraldehyde-based disinfectant was effective in eliminating all microbial forms for both alginate and silicone without modifying the dimensional stability. Alcohol-based disinfectants, however, reduced the alginate shrinkage during the first 90 minutes of setting. The current studies

  18. Disinfection and regrowth potential of bacillus subtilis spores by ozone, ultraviolet rays and gamma irradiation

    International Nuclear Information System (INIS)

    Kim, Hae Yeon; Lee, O Mi; Kim, Tae Hun; Lee, Myun Joo; Yu, Seung Ho

    2009-01-01

    Chlorination has been the most commonly adopted disinfection process for the treatment of drinking water. However, Cryptosporidium parvum oocysts and Giardia lamblia cysts were not treated effectively by the common chlorine-based disinfectants. Additionally the regrowth of pathogenic microorganisms is associated with hygienic and aesthetic problems for the consumers of drinking water. Study on alternative disinfection processes such as ozone, UV-C, VUV and gamma irradiation were conducted. Bacillus subtilis spores have been used as a surrogate microorganism for Cryptosporidium parvum oocysts and Giardia lamblia cyst. Inactivation efficiency by ozone was from 30% to 96% within the range of 5 min to 120 min exposures. Inactivation efficiencies by UV-C and VUV were 95.18%, 95.07% at 30 sec, respectively. Inactivation efficiency at gamma irradiation dose of 2 kGy was 99.4%. Microbial regrowths after ozone, UV-C, VUV and gamma irradiation disinfections were also evaluated for 4 days. Bacillus subtilis spores after ozone treatment for 120 min exposure at the rate of 1.68 mg · min -1 showed 96.02% disinfection efficiency and significant microbial regrowth. Bacillus subtilis spores after UV-C (99.25% disinfection efficiency) and VUV (99.67% disinfection efficiency) treatments for 5 min showed gradual regrowth. However, inactivation efficiency of gamma irradiation at dose of 1 kGy was 98.8% and the disinfected sample showed no microbial regrowth for 4 days. Therefore, gamma irradiation is the most effective process for the disinfection of pathogenic microorganisms such as oocysts of protozoan parasites among four disinfection process

  19. Modern technologies for improving cleaning and disinfection of environmental surfaces in hospitals

    Directory of Open Access Journals (Sweden)

    John M. Boyce

    2016-04-01

    Full Text Available Abstract Experts agree that careful cleaning and disinfection of environmental surfaces are essential elements of effective infection prevention programs. However, traditional manual cleaning and disinfection practices in hospitals are often suboptimal. This is often due in part to a variety of personnel issues that many Environmental Services departments encounter. Failure to follow manufacturer’s recommendations for disinfectant use and lack of antimicrobial activity of some disinfectants against healthcare-associated pathogens may also affect the efficacy of disinfection practices. Improved hydrogen peroxide-based liquid surface disinfectants and a combination product containing peracetic acid and hydrogen peroxide are effective alternatives to disinfectants currently in widespread use, and electrolyzed water (hypochlorous acid and cold atmospheric pressure plasma show potential for use in hospitals. Creating “self-disinfecting” surfaces by coating medical equipment with metals such as copper or silver, or applying liquid compounds that have persistent antimicrobial activity surfaces are additional strategies that require further investigation. Newer “no-touch” (automated decontamination technologies include aerosol and vaporized hydrogen peroxide, mobile devices that emit continuous ultraviolet (UV-C light, a pulsed-xenon UV light system, and use of high-intensity narrow-spectrum (405 nm light. These “no-touch” technologies have been shown to reduce bacterial contamination of surfaces. A micro-condensation hydrogen peroxide system has been associated in multiple studies with reductions in healthcare-associated colonization or infection, while there is more limited evidence of infection reduction by the pulsed-xenon system. A recently completed prospective, randomized controlled trial of continuous UV-C light should help determine the extent to which this technology can reduce healthcare-associated colonization and infections

  20. Disinfection and regrowth potential of bacillus subtilis spores by ozone, ultraviolet rays and gamma irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hae Yeon; Lee, O Mi; Kim, Tae Hun; Lee, Myun Joo; Yu, Seung Ho [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of)

    2009-06-15

    Chlorination has been the most commonly adopted disinfection process for the treatment of drinking water. However, Cryptosporidium parvum oocysts and Giardia lamblia cysts were not treated effectively by the common chlorine-based disinfectants. Additionally the regrowth of pathogenic microorganisms is associated with hygienic and aesthetic problems for the consumers of drinking water. Study on alternative disinfection processes such as ozone, UV-C, VUV and gamma irradiation were conducted. Bacillus subtilis spores have been used as a surrogate microorganism for Cryptosporidium parvum oocysts and Giardia lamblia cyst. Inactivation efficiency by ozone was from 30% to 96% within the range of 5 min to 120 min exposures. Inactivation efficiencies by UV-C and VUV were 95.18%, 95.07% at 30 sec, respectively. Inactivation efficiency at gamma irradiation dose of 2 kGy was 99.4%. Microbial regrowths after ozone, UV-C, VUV and gamma irradiation disinfections were also evaluated for 4 days. Bacillus subtilis spores after ozone treatment for 120 min exposure at the rate of 1.68 mg {center_dot} min{sup -1} showed 96.02% disinfection efficiency and significant microbial regrowth. Bacillus subtilis spores after UV-C (99.25% disinfection efficiency) and VUV (99.67% disinfection efficiency) treatments for 5 min showed gradual regrowth. However, inactivation efficiency of gamma irradiation at dose of 1 kGy was 98.8% and the disinfected sample showed no microbial regrowth for 4 days. Therefore, gamma irradiation is the most effective process for the disinfection of pathogenic microorganisms such as oocysts of protozoan parasites among four disinfection process.

  1. Disinfection of herbal spa pool using combined chlorine dioxide and sodium hypochlorite treatment.

    Science.gov (United States)

    Hsu, Ching-Shan; Huang, Da-Ji

    2015-02-01

    The presence of pathogenic microorganisms in public spa pools poses a serious threat to human health. The problem is particularly acute in herbal spas, in which the herbs and microorganisms may interact and produce undesirable consequences. Accordingly, the present study investigated the effectiveness of a combined disinfectant containing chlorine dioxide and sodium hypochlorite in improving the water quality of a public herbal spa in Taiwan. Water samples were collected from the spa pool and laboratory tests were then performed to measure the variation over time of the microorganism content (total CFU and total coliforms) and residual disinfectant content given a single disinfection mode (SDM) with disinfectant concentrations of 5.2 × 10, 6.29 × 10, 7.4 × 10, and 11.4 × 10(-5) N, respectively. Utilizing the experience gained from the laboratory tests, a further series of on-site investigations was performed using three different disinfection modes, namely SDM, 3DM (once every 3 h disinfection mode), and 2DM (once every 2 h disinfection mode). The laboratory results showed that for all four disinfectant concentrations, the CFU concentration reduced for the first 6 h following SDM treatment, but then increased. Moreover, the ANOVA results showed that the sample treated with the highest disinfectant concentration (11.4 × 10(-5) N) exhibited the lowest rate of increase in the CFU concentration. In addition, the on-site test results showed that 3DM and 2DM treatments with disinfectant concentrations in excess of 9.3 × 10 and 5.5 × 10(-5) N, respectively, provided an effective reduction in the total CFU concentration. In conclusion, the experimental results presented in this study provide a useful source of reference for spa businesses seeking to improve the water quality of their spa pools.

  2. Synergistic effect of ultrasonic pre-treatment combined with UV irradiation for secondary effluent disinfection.

    Science.gov (United States)

    Jin, Xin; Li, Zifu; Xie, Lanlan; Zhao, Yuan; Wang, Tingting

    2013-11-01

    The ultraviolet (UV) disinfection efficiency is often affected by suspended solids (SS). Given their high concentration or large particle size, SS can scatter UV light and provide shielding for bacteria. Thus, ultrasound is often employed as a pre-treatment process to improve UV disinfection. This work investigated the synergistic effect of ultrasound combined with UV for secondary effluent disinfection. Bench-scale experiments were conducted in using samples obtained from secondary sedimentation tanks. These tanks belonged to three wastewater treatment plants in Beijing that use different kinds of biological treatment methods. Several parameters may contribute to the changes in the efficiency of ultrasound and UV disinfection. Thus, the frequency and energy density of ultrasound, as well as the SS, were investigated. Results demonstrated that samples which have relatively higher SS concentrations or higher percentages of larger particles have less disinfection efficiency using UV disinfection alone. However, the presence of ultrasound could improve the disinfection efficiency because it has synergistic effect. Changes in the particle size distribution and SS concentration notably affected the efficiency of UV disinfection. The efficiency of Escherichia coli elimination can be decreased by 1.2 log units as the SS concentration increases from 16.9 mg/l to 25.4 mg/l at a UV energy density of 40 mJ/cm(2). UV disinfection alone reduced the E. coli population by 3.4 log units. However, the synergistic disinfection of ultrasound and UV could reach 5.4 log units during the reduction of E. coli at a 40 kHz frequency and an energy density of 2.64 kJ/l. The additional synergistic effect is 1.1 log units. Copyright © 2013 Elsevier B.V. All rights reserved.

  3. Surface disinfection tests with Salmonella and a putative indicator bacterium, mimicking worst-case scenarios in poultry houses

    DEFF Research Database (Denmark)

    Gradel, K.O.; Sayers, A.R.; Davies, R.H.

    2004-01-01

    Surface disinfection studies mimicking worst-case scenarios in badly cleaned poultry houses were made with 3 bacterial isolates (Salmonella enteritidis, Salmonella senftenberg, and Enterococcus faecalis), and 3 1% disinfectant solutions, formaldehyde (F; 24.5% vol/vol), glutaraldehyde...... hard water, except when feed chain links with fats were disinfected using 30degreesC before and after disinfection, for which the peroxygen compound seemed more effective. Enterococcus faecalis was equally or less susceptible than S. enteritidis and S. senftenberg, indicating its suitability...... as an indicator bacterium. For the peroxygen compound, S. senftenberg was more susceptible than S. enteritidis in spite of higher minimum inhibitory concentrations to this disinfectant for the former....

  4. Disinfection of Ebola Virus in Sterilized Municipal Wastewater.

    Directory of Open Access Journals (Sweden)

    Kyle Bibby

    2017-02-01

    Full Text Available Concerns have been raised regarding handling of Ebola virus contaminated wastewater, as well as the adequacy of proposed disinfection approaches. In the current study, we investigate the inactivation of Ebola virus in sterilized domestic wastewater utilizing sodium hypochlorite addition and pH adjustment. No viral inactivation was observed in the one-hour tests without sodium hypochlorite addition or pH adjustment. No virus was recovered after 20 seconds (i.e. 4.2 log10 unit inactivation to detection limit following the addition of 5 and 10 mg L-1 sodium hypochlorite, which resulted in immediate free chlorine residuals of 0.52 and 1.11 mg L-1, respectively. The addition of 1 mg L-1 sodium hypochlorite resulted in an immediate free chlorine residual of 0.16 mg L-1, which inactivated 3.5 log10 units of Ebola virus in 20 seconds. Further inactivation was not evident due to the rapid consumption of the chlorine residual. Elevating the pH to 11.2 was found to significantly increase viral decay over ambient conditions. These results indicate the high susceptibility of the enveloped Ebola virus to disinfection in the presence of free chlorine in municipal wastewater; however, we caution that extension to more complex matrices (e.g. bodily fluids will require additional verification.

  5. Use of ultraviolet-disinfected nutrient solutions in greenhouses

    International Nuclear Information System (INIS)

    Acher, A.; Heuer, B.; Rubinskaya, E.; Fischer, E.

    1997-01-01

    Environmental concerns and economics require the recycling of plant nutrient solutions (PNS) used in soilless cultures in greenhouses. To avoid possible outbreaks of plant diseases, disinfection of the recycled PNS might be necessary. This paper describes a case study on the stability of Fe 3+ -chelates, present in PNS and exposed to ultraviolet radiation (UV 254 nm) for disinfection, and the effect on plant growth. Three Fe-chelates, each containing 2 mg Fe 3+ l -1 , in PNS were: i, Fe-EDDHA (Fe-ethylene-diamine-dihydroxyphenyl acetic acid); ii, Fe-Na-EDTA (Fe-ethylene-diamine-tetraacetic acid); and iii, Fe-DTPA (Fe-diethylene-triamine-pentaacetic acid). Seedlings of sorghum, corn and tomatoes were grown hydroponically for four weeks in continuously aerated PNS, which had been exposed previously for 0, 2.5 and 130 s to a UV radiation fluence of 80 mW s -1 cm -2 . The accumulation of plant fresh weight (APFW) differed from non-treated controls, depending on chelating agent and on exposure time to UV. The greatest APFW was observed in sorghum (128, 178 and 98%) at 2.5 s UV-exposure for PNS containing i, ii and iii, respectively. For corn and tomato, the respective results were: 108, 139 and 96%, and 129, 91 and 89% for tomatoes, respectively. The stability of i, ii and iii upon exposure to UV radiation is discussed. (author)

  6. Disinfection Methods for Swimming Pool Water: Byproduct Formation and Control

    Directory of Open Access Journals (Sweden)

    Huma Ilyas

    2018-06-01

    Full Text Available This paper presents a comprehensive and critical comparison of 10 disinfection methods of swimming pool water: chlorination, electrochemically generated mixed oxidants (EGMO, ultraviolet (UV irradiation, UV/chlorine, UV/hydrogen peroxide (H2O2, UV/H2O2/chlorine, ozone (O3/chlorine, O3/H2O2/chlorine, O3/UV and O3/UV/chlorine for the formation, control and elimination of potentially toxic disinfection byproducts (DBPs: trihalomethanes (THMs, haloacetic acids (HAAs, haloacetonitriles (HANs, trihaloacetaldehydes (THAs and chloramines (CAMs. The statistical comparison is carried out using data on 32 swimming pools accumulated from the reviewed studies. The results indicate that O3/UV and O3/UV/chlorine are the most promising methods, as the concentration of the studied DBPs (THMs and HANs with these methods was reduced considerably compared with chlorination, EGMO, UV irradiation, UV/chlorine and O3/chlorine. However, the concentration of the studied DBPs including HAAs and CAMs remained much higher with O3/chlorine compared with the limits set by the WHO for drinking water quality. Moreover, the enhancement in the formation of THMs, HANs and CH with UV/chlorine compared with UV irradiation and the increase in the level of HANs with O3/UV/chlorine compared with O3/UV indicate the complexity of the combined processes, which should be optimized to control the toxicity and improve the quality of swimming pool water.

  7. Industrial Cooling Tower Disinfection Treatment to Prevent Legionella spp.

    Science.gov (United States)

    Iervolino, Matteo; Mancini, Benedetta; Cristino, Sandra

    2017-09-26

    The contamination of industrial cooling towers has been identified as one cause of legionellosis, but the real risk has been underestimated. Two different disinfection treatments were tested on Legionella colonization in an industrial Cooling Tower System (CTS). Environmental monitoring of Legionella , P. aeruginosa , and a heterotrophic plate count (HPC) at 36 °C was performed from June to October 2016. The disinfection procedures adopted were based on hydrogen peroxide (H₂O₂) and silver salts (Ag⁺), in addition to an anti-algal treatment, then using hyperclorination as a shock, and then continuous treatment by sodium hypochlorite (NaClO). L . pneumophila serogroup 8 was found at a concentration of 5.06 Log cfu/L after the CTS filling; a shock treatment performed by H₂O₂/Ag⁺ produced a rapid increase in contamination up to 6.14 Log cfu/L. The CTS activity was stopped and two subsequent shock treatments were performed using NaClO, followed by continuous hyperclorination. These procedures showed a significant decrease ( p Legionella concentration (1.77 Log cfu/L). The same trend was observed for P . aeruginosa (0.55 Log cfu/100 mL) and HPC (1.95 Log cfu/mL) at 36 °C. Environmental monitoring and the adoption of maintenance procedures, including anti-scale treatment, and physical, chemical, and microbiological control, ensure the good performance of a CTS, reducing the Legionella risk for public health.

  8. High energy electron disinfection of sewage wastewater in flow systems

    Energy Technology Data Exchange (ETDEWEB)

    Miyata, T; Arai, H; Hosono, M; Tokunaga, O; Machi, S [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment; Kondoh, M; Minemura, T; Nakao, A; Seike, Y [Sumitomo Heavy Industries Ltd., Tokyo (Japan)

    1990-01-01

    The disinfection of effluent municipal wastewaters by high-energy electrons in flow systems was studied using an experimental apparatus which has the maximum treatment capacity of 10.8 m{sup 3}/h. An electron accelerator with an accelerating voltage of 2 MV was used. The electron beam current was controlled to deliver the desired doses ranging from 0.05 to 1 kGy. Treatment times were in the range from 0.0022 to 0.051 s. Preliminary experiments with batch system using Petri dish of 100 ml showed that the effectiveness of electron irradiation on inactivation of coliforms was not influenced significantly by factors such as pH, SS, COD, DO and irradiation temperature. The dose required to produce 99.9% kill in the total population presented in wastewater were markedly affected by the thickness of water exposure to electron irradiation; that is, 0.39, 0.4 and 0.44 kGy for the depth of 5, 6 and 7 mm, respectively. The data obtained after a suitable correction for the doses due to the depth dose distribution showed no deviation from an experimental survival curve. Experiments with flow system indicated no measureable effect of the flow rate of wastewaters on the efficiency of disinfection in the range from 0.5 to 3.5 m/s. (author).

  9. Dynamics of cholera epidemics with impulsive vaccination and disinfection.

    Science.gov (United States)

    Sisodiya, Omprakash Singh; Misra, O P; Dhar, Joydip

    2018-04-01

    Waterborne diseases have a tremendous influence on human life. The contaminated drinking water causes water-borne disease like cholera. Pulse vaccination is an important and effective strategy for the elimination of infectious diseases. A waterborne disease like cholera can also be controlled by using impulse technique. In this paper, we have proposed a delayed SEIRB epidemic model with impulsive vaccination and disinfection. We have studied the pulse vaccination strategy and sanitation to control the cholera disease. The existence and stability of the disease-free and endemic periodic solution are investigated both analytically and numerically. It is shown that there exists an infection-free periodic solution, using the impulsive dynamical system defined by the stroboscopic map. It is observed that the infection-free periodic solution is globally attractive when the impulse period is less than some critical value. From the analysis of the model, we have obtained a sufficient condition for the permanence of the epidemic with pulse vaccination. The main highlight of this paper is to introduce impulse technique along with latent period into the SEIRB epidemic model to investigate the role of pulse vaccination and disinfection on the dynamics of the cholera epidemics. Copyright © 2018 Elsevier Inc. All rights reserved.

  10. Applying a uniform layer of disinfectant by wiping.

    Science.gov (United States)

    Cooper, D W

    2000-01-01

    Disinfection or sterilization often requires applying a film of liquid to a surface, frequently done by using a wiper as the applicator. The wiper must not only hold a convenient amount of liquid, it must deposit it readily and uniformly. Contact time is critical to disinfection efficacy. Evaporation can limit the contact time. To lengthen the contact time, thickly applied layers are generally preferred. The thickness of such layers can be determined by using dyes or other tracers, as long as the tracers do not significantly affect the liquid's surface tension and viscosity and thus do not affect the thickness of the applied layer. Alternatively, as done here, the thickness of the layer can be inferred from the weight loss of the wiper. Results are reported of experiments on thickness of the layers applied under various conditions. Near saturation, hydrophilic polyurethane foam wipers gave layers roughly 10 microns thick, somewhat less than expected from hydrodynamic theory, but more than knitted polyester or woven cotton. Wipers with large liquid holding capacity, refilled often, should produce more nearly uniform layers. Higher pressures increase saturation in the wiper, tending to thicken the layer, but higher pressures also force liquid from the interface, tending to thin the layer, so the net result could be thicker or thinner layers, and there is likely to be an optimal pressure.

  11. Disinfection of Ebola Virus in Sterilized Municipal Wastewater.

    Science.gov (United States)

    Bibby, Kyle; Fischer, Robert J; Casson, Leonard W; de Carvalho, Nathalia Aquino; Haas, Charles N; Munster, Vincent J

    2017-02-01

    Concerns have been raised regarding handling of Ebola virus contaminated wastewater, as well as the adequacy of proposed disinfection approaches. In the current study, we investigate the inactivation of Ebola virus in sterilized domestic wastewater utilizing sodium hypochlorite addition and pH adjustment. No viral inactivation was observed in the one-hour tests without sodium hypochlorite addition or pH adjustment. No virus was recovered after 20 seconds (i.e. 4.2 log10 unit inactivation to detection limit) following the addition of 5 and 10 mg L-1 sodium hypochlorite, which resulted in immediate free chlorine residuals of 0.52 and 1.11 mg L-1, respectively. The addition of 1 mg L-1 sodium hypochlorite resulted in an immediate free chlorine residual of 0.16 mg L-1, which inactivated 3.5 log10 units of Ebola virus in 20 seconds. Further inactivation was not evident due to the rapid consumption of the chlorine residual. Elevating the pH to 11.2 was found to significantly increase viral decay over ambient conditions. These results indicate the high susceptibility of the enveloped Ebola virus to disinfection in the presence of free chlorine in municipal wastewater; however, we caution that extension to more complex matrices (e.g. bodily fluids) will require additional verification.

  12. [Surveillance cultures after high-level disinfection of flexible endoscopes in a general hospital].

    Science.gov (United States)

    Robles, Christian; Turín, Christie; Villar, Alicia; Huerta-Mercado, Jorge; Samalvides, Frine

    2014-04-01

    Flexible endoscopes are instruments with a complex structure which are used in invasive gastroenterological procedures, therefore high-level disinfection (HLD) is recommended as an appropriate reprocessing method. However, most hospitals do not perform a quality control to assess the compliance and results of the disinfection process. To evaluate the effectiveness of the flexible endoscopes’ decontamination after high-level disinfection by surveillance cultures and to assess the compliance with the reprocessing guidelines. Descriptive study conducted in January 2013 in the Gastroenterological Unit of a tertiary hospital. 30 endoscopic procedures were randomly selected. Compliance with guidelines was evaluated and surveillance cultures for common bacteria were performed after the disinfection process. On the observational assessment, compliance with the guidelines was as follows: pre-cleaning 9 (30%), cleaning 5 (16.7%), rinse 3 (10%), first drying 30 (100%), disinfection 30 (100%), final rinse 0 (0%) and final drying 30 (100%), demonstrating that only 3 of 7 stages of the disinfection process were optimally performed. In the microbiological evaluation, 2 (6.7%) of the 30 procedures had a positive culture obtained from the surface of the endoscope. Furthermore, 1 (4.2%) of the 24 biopsy forcepsgave a positive culture. The organisms isolated were different Pseudomonas species. High-level disinfection procedures were not optimally performed, finding in 6.7% positive cultures of Pseudomonas species.

  13. Effect of alginate chemical disinfection on bacterial count over gypsum cast.

    Science.gov (United States)

    Haralur, Satheesh B; Al-Dowah, Omir S; Gana, Naif S; Al-Hytham, Abdullah

    2012-05-01

    To evaluate the efficacy of sodium hypochlorite (1 : 10) and iodophor disinfectants on alginate impressions along with their effect on the survived bacterium count on the gypsum cast. Four alginate impression on each dentate patients were made, of which Group I were not washed or disinfected, Group II impressions were merely washed with water, Group III were disinfected by spraying with sodium hypochlorite (1 : 10), Group IV were disinfected with iodophor (1 : 213). Gypsum cast (type III) were made from all the impression. Impressions and gypsum cast were swabbed in mid palatal region for bacterial culture. Bacterial colony counting done after 3 days of incubation at 37℃ in blood agar media. The data obtained was analyzed by one way ANOVA test at a significant difference level of 0.05. Group I and Group II showed significantly more bacteria compared to Group III and Group IV. Bacterial colonies on the alginate impression and gypsum cast in group disinfected with Sodium hypochlorite (1 : 10) were 0.18, 0.82 respectively compared to group treated with iodophor (1 : 213). There was an increase in bacterial count on dental cast compared to source alginate impressions. Sodium hypochlorite (1 : 10) was found to be better disinfectant for alginate impression. There was an indication of increase in number of bacteria from alginate impression to making of dental cast. Additional gypsum cast disinfectant procedures need to be encouraged to completely eliminate cross infection to dental laboratory.

  14. Life Cycle Environmental Impacts of Disinfection Technologies Used in Small Drinking Water Systems.

    Science.gov (United States)

    Jones, Christopher H; Shilling, Elizabeth G; Linden, Karl G; Cook, Sherri M

    2018-03-06

    Small drinking water systems serve a fifth of the U.S. population and rely heavily on disinfection. While chlorine disinfection is common, there is interest in minimizing chemical addition, especially due to carcinogenic disinfection byproducts and chlorine-resistant pathogens, by using ultraviolet technologies; however, the relative, broader environmental impacts of these technologies are not well established, especially in the context of small (environmental trade-offs between chlorine and ultraviolet disinfection via comparative life cycle assessment. The functional unit was the production of 1 m 3 of drinking water to U.S. Treatment included cartridge filtration followed by either chlorine disinfection or ultraviolet disinfection with chlorine residual addition. Environmental performance was evaluated for various chlorine contact zone materials (plastic, concrete, steel), ultraviolet validation factors (1.2 to 4.4), and electricity sources (renewable; U.S. average, high, and low impact grids). Performance was also evaluated when filtration and chlorine residual were not required. From a life cycle assessment perspective, replacing chlorine with UV was preferred only in a limited number of cases (i.e., high pumping pressure but filtration is not required). In all others, chlorine was environmentally preferred, although some contact zone materials and energy sources had an impact on the comparison. Utilities can use these data to inform their disinfection technology selection and operation to minimize environmental and human health impacts.

  15. [Hydrogen peroxide, chloramine T and chlorhexidrine in the disinfection of acrylic resin].

    Science.gov (United States)

    Czerwińska, W; Kedzia, A; Kałowski, M

    1978-01-01

    The effectiveness of 3% h drogen peroxide, 5% chloramine T and 0,5% chlorhexidine gluconate solutions in disinfection of acrylic resine plates massively infected with oral flora was analysed. The acrylic resine plates used for investigations, were infected in vitro with mixed salivary flora characterized by small numbers of yeast-like fungi (1st group), or great number of these microorganisms (2nd group). Infected plates were exposed to solutions of analysed disinfectants during various time periods. After rinsing or inactivation of disinfectant residues, acrylic plates were put into bacteriological medium and incubated during 7 days period in 37 degrees C. The results of this study indicated the effectiveness of acrylic plates disinfection to be dependent on used disinfectant, time of exposition, and microorganisms present on the surface of acrylic resine. The solutions of disinfectants were less active in the cases of plates infected with material containing great numbers of yeast-like microorganisms. Among analysed disinfectants 0,5% solution of chlorhexidine was characterized by most effective and rapid activity, whereas 3% solution of hydrogen peroxide was found to be the least effective.

  16. Cross-Resistance of UV- or Chlorine Dioxide-Resistant Echovirus 11 to Other Disinfectants

    Directory of Open Access Journals (Sweden)

    Qingxia Zhong

    2017-10-01

    Full Text Available The emergence of waterborne viruses with resistance to disinfection has been demonstrated in the laboratory and in the environment. Yet, the implications of such resistance for virus control remain obscure. In this study we investigate if viruses with resistance to a given disinfection method exhibit cross-resistance to other disinfectants. Chlorine dioxide (ClO2- or UV-resistant populations of echovirus 11 were exposed to five inactivating treatments (free chlorine, ClO2, UV radiation, sunlight, and heat, and the extent of cross-resistance was determined. The ClO2-resistant population exhibited cross-resistance to free chlorine, but to none of the other inactivating treatments tested. We furthermore demonstrated that ClO2 and free chlorine act by a similar mechanism, in that they mainly inhibit the binding of echovirus 11 to its host cell. As such, viruses with host binding mechanisms that can withstand ClO2 treatment were also better able to withstand oxidation by free chlorine. Conversely, the UV-resistant population was not significantly cross-resistant to any other disinfection treatment. Overall, our results indicate that viruses with resistance to multiple disinfectants exist, but that they can be controlled by inactivating methods that operate by a distinctly different mechanism. We therefore suggest to utilize two disinfection barriers that act by different mechanisms in order to control disinfection-resistant viruses.

  17. Efficacy of cleaning and disinfection procedures in a zebrafish (Danio rerio) facility.

    Science.gov (United States)

    Garcia, Rachel L; Sanders, George E

    2011-11-01

    Appropriate cleaning and disinfection procedures in zebrafish (Danio rerio) laboratories are crucial in preventing the spread of aquatic animal pathogens and minimizing the build-up of waste products and biologic matter. The procedures selected should accomplish these goals and incorporate the individual needs of various laboratories. In this study of a single zebrafish facility, we assessed the efficacy of 2 different cleaning and disinfection procedures for nets, tanks, and lids. ATP levels were used as a surrogate biomarker for microbial burden. We measured the number of relative light units (RLU), as an expression of the amount of ATP present, on items before and after disinfection and calculated the percentage reduction. We compared daily replacement of a commercial net disinfection product in J lab with weekly replacement in H lab and found a 96.6% reduction in RLU in H lab and a 91.2% reduction in J lab. These results indicate that either replacement schedule is effective. Evaluation of tanks and lids soaked in a bleach disinfection bath for 30 or 60 min revealed a 99.7% reduction in RLU at 30 min compared with 97.1% at 60 min. Therefore a 30-min soak in a bleach bath achieved a similar level of disinfection as did a 60-min soak. The current results demonstrate that these cleaning and disinfection methods are efficacious.

  18. Demonstration of disinfection procedure for the development of accurate blood glucose meters in accordance with ISO 15197:2013

    Science.gov (United States)

    Lin, Wen-Ye; Chang, Jung-Tzu; Chu, Chun-Feng

    2017-01-01

    Despite measures to reduce disease transmission, a risk can occur when blood glucose meters (BGMs) are used on multiple individuals or by caregivers assisting a patient. The laboratory and in-clinic performance of a BGM system before and after disinfection should be demonstrated to guarantee accurate readings and reliable control of blood glucose (BG) for patients. In this study, an effective disinfection procedure, conducting wiping 10 times to assure a one minute contact time of the disinfectant on contaminated surface, was first demonstrated using test samples of the meter housing materials, including acrylonitrile butadiene styrene (ABS), polymethyl methacrylate (PMMA), and polycarbonate (PC), in accordance with ISO 15197:2013. After bench studies comprising 10,000 disinfection cycles, the elemental compositions of the disinfected ABS, PMMA, and PC samples were almost the same as in the original samples, as indicated by electron spectroscopy for chemical analysis. Subsequently, the validated disinfection procedure was then directly applied to disinfect 5 commercial BGM systems composed of ABS, PMMA, or PC to observe the effect of the validated disinfection procedure on meter accuracy. The results of HBsAg values after treatment with HBV sera and disinfectant wipes for each material were less than the LoD of each material of 0.020 IU/mL. Before and after the multiple disinfection cycles, 900 of 900 samples (100%) were within the system accuracy requirements of ISO 15197:2013. All of the systems showed high performance before and after the series of disinfection cycles and met the ISO 15197:2013 requirements. In addition, our results demonstrated multiple cleaning and disinfection cycles that represented normal use over the lifetime of a meter of 3–5 years. Our validated cleaning and disinfection procedure can be directly applied to other registered disinfectants for cleaning commercial BGM products in the future. PMID:28683148

  19. [Assessment of disinfection and sterilization processes in dental practice as an important factors in prevention of infections].

    Science.gov (United States)

    Podgórska, Marta; Jakimiak, Bozenna; Röhm-Rodowald, Ewa; Chojecka, Agnieszka

    2009-01-01

    The dental health-care settings is an environment where disease transmission occurs easily. Prevention of cross infection is therefore a crucial aspect of dental practice and dental clinic stuffmust adopt certain basic routines while practicing. Infections may be transmitted in the dental operatory through direct contact with blood, oral fluids or other secretions; via indirect contact with contaminated instruments, equipment or environmental surfaces; or by contact with airborne contaminants present in either droplet splatter or aerosols of oral and respiratory fluids. Strategies to prevent dental patient infections have focused on disinfection and sterilization. This study evaluates basic routines in prevention of cross-infection in the dentistry. The sample comprised 100 dentists, who completed questionnaires. Based on inquires the conditions for disinfection and sterilization of medical devices were assessed. The following issues were taken into consideration: the way of disinfection and preparation of the disinfectants, the localization of disinfection, preparing to disinfection, washing and packing of dental devices, the frequency of disinfection, methods of sterilization and the monitoring system, type of sterilizers and the available cycles. The dental practices are well equiped to proceed the steam sterilization, but 33% of dentists don't know the available cycles in their autoclaves. Only 35% of them made sterilization process protocols. Very common are three failures of instruments disinfections: multiple use of disinfectant, adding of disinfectant, adding new instruments. There is still need for improvement in disinfection and sterilization in dental practice, especially including: monitoring and documentation of sterilization process, proper use of disinfectants according to manufactures instructions, frequent disinfection of surfaces which contact with patients. Dental stuff should take part in advanced training courses about disinfection and

  20. In situ disinfection of sewage contaminated shallow groundwater: a feasibility study.

    Science.gov (United States)

    Bailey, Morgan M; Cooper, William J; Grant, Stanley B

    2011-11-01

    Sewage-contaminated shallow groundwater is a potential cause of beach closures and water quality impairment in marine coastal communities. In this study we set out to evaluate the feasibility of several strategies for disinfecting sewage-contaminated shallow groundwater before it reaches the coastline. The disinfection rates of Escherichia coli (EC) and enterococci bacteria (ENT) were measured in mixtures of raw sewage and brackish shallow groundwater collected from a coastal community in southern California. Different disinfection strategies were explored, ranging from benign (aeration alone, and aeration with addition of brine) to aggressive (chemical disinfectants peracetic acid (PAA) or peroxymonosulfate (Oxone)). Aeration alone and aeration with brine did not significantly reduce the concentration of EC and ENT after 6 h of exposure, while 4-5 mg L(-1) of PAA or Oxone achieved >3 log reduction after 15 min of exposure. Oxone disinfection was more rapid at higher salinities, most likely due to the formation of secondary oxidants (e.g., bromine and chlorine) that make this disinfectant inappropriate for marine applications. Using a Lagrangian modeling framework, we identify several factors that could influence the performance of in-situ disinfection with PAA, including the potential for bacterial regrowth, and the non-linear dependence of disinfection rate upon the residence time of water in the shallow groundwater. The data and analysis presented in this paper provide a framework for evaluating the feasibility of in-situ disinfection of shallow groundwater, and elucidate several topics that warrant further investigation. Copyright © 2011 Elsevier Ltd. All rights reserved.

  1. Efficacy of detergent and water versus bleach for disinfection of direct contact ophthalmic lenses.

    Science.gov (United States)

    Abbey, Ashkan M; Gregori, Ninel Z; Surapaneni, Krishna; Miller, Darlene

    2014-06-01

    Although manufacturers recommend cleaning ophthalmic lenses with detergent and water and then with a specific disinfectant, disinfectants are rarely used in ophthalmic practices. The aim of this pilot study was to evaluate the efficacy of detergent and water versus that of bleach, a recommended disinfectant, to eliminate common ocular bacteria and viruses from ophthalmic lenses. Three bacterial strains (Staphylococcus epidermidis, Corynebacterium straitum, and methicillin-resistant Staphylococcus aureus and 2 viral strains (adenovirus and herpes simplex virus [HSV] type-1) were individually inoculated onto 20 gonioscopy and laser lenses. The lenses were washed with detergent and water and then disinfected with 10% bleach. All the lenses were cultured after inoculation, after washing with detergent and water, and after disinfecting with the bleach. Bacterial cultures in thioglycollate broth were observed for 3 weeks, and viral cultures were observed for 2 weeks. The presence of viruses was also detected by multiplex polymerase chain reaction (PCR). All 20 lenses inoculated with S. epidermidis, C. straitum, adenovirus, and HSV-1 showed growth after inoculation but no growth after washing with detergent/water and after disinfecting with the bleach. All lenses showed positive HSV and adenovirus PCR results after inoculation and negative PCR results after washing with detergent/water and after disinfecting with bleach. All methicillin-resistant S. aureus-contaminated lenses showed growth after inoculation and no growth after washing with detergent and water. However, 1 lens showed positive growth after disinfecting with bleach. Cleaning with detergent and water seemed to effectively eliminate bacteria and viruses from the surface of contaminated ophthalmic lenses. Further studies are warranted to design practical disinfection protocols that minimize lens damage.

  2. Evaluation of different sterilization and disinfection methods on commercially made preformed crowns.

    Science.gov (United States)

    Yilmaz, Y; Guler, C

    2008-12-01

    The aim of this study was to evaluate the changes caused by different sterilization or disinfection methods on the vestibular surface of four commercially made preformed crowns using stereomicroscopy and scanning electron microscopy (SEM). Preformed crowns (NuSmile Primary Anterior Crown (NSC), Kinder Krowns (KK), Pedo Pearls (PP) and polycarbonate crowns (PC)) were sterilized and/or disinfected by one of the following techniques: no sterilization or disinfection (G1 control group); steam autoclaving at 134 degrees C (30 psi) for 4 min (G2); steam autoclaving at 134 degrees C (30 psi) for 12 min (G3); steam autoclaving at 121 degrees C (15 psi) for 30 min (G4); and ultrasonication in a bath containing 4% Lysetol AF for 5 min at room temperature (chemical disinfection) (G5). Scanning electron micrographs of the crowns were taken before and after their sterilization or disinfection. The changes on the vestibular surface were then scored for the presence or absence of crazing, contour alteration, fracturing, and vestibular surface changes. The data were analyzed statistically using the chi-square test. No changes were observed before and after sterilization or disinfection in the stereomicroscopic evaluation of the vestibular surface of the crowns. However, all methods in which steam autoclaving was used to sterilize the crowns caused significant (P < 0.05) crazing and contour alterations of the vestibular surface of the crowns when they were examined by SEM. Chemical disinfection using an aldehyde-free disinfectant is the preferred method of disinfection for crowns that have been used previously in other dental patients.

  3. Disinfection of indoor air microorganisms in stack room of university library using gaseous chlorine dioxide.

    Science.gov (United States)

    Hsu, Ching-Shan; Lu, Ming-Chun; Huang, Da-Ji

    2015-02-01

    As with all indoor public spaces in Taiwan, the stack rooms in public libraries should meet the air quality guidelines laid down by the Taiwan Environmental Protection Administration. Accordingly, utilizing a university library in Taiwan for experimental purposes, this study investigates the efficiency of gaseous chlorine dioxide (ClO2) as a disinfection agent when applied using three different treatment modes, namely a single-daily disinfection mode (SIM), a twice-daily disinfection mode (TWM), and a triple-daily disinfection mode (TRM). For each treatment mode, the ClO2 is applied using an ultrasonic aerosol device and is performed both under natural lighting conditions and under artificial lighting conditions. The indoor air quality is evaluated before and after each treatment session by measuring the bioaerosol levels of bacteria and fungi. The results show that for all three disinfection modes, the application of ClO2 reduces the indoor bacteria and fungi concentrations to levels lower than those specified by the Taiwan EPA (i.e., bacteria <1500 CFU/m(3), fungi <1000 CFU/m(3)), irrespective of the lighting conditions under which the disinfection process is performed. For each disinfection mode, a better disinfection efficiency is obtained under natural lighting conditions since ClO2 readily decomposes under strong luminance levels. Among the three treatment modes, the disinfection efficiencies of the TWM and TRM modes are very similar under natural lighting conditions and are significantly better than that of the SIM mode. Thus, overall, the results suggest that the TWM treatment protocol represents the most cost-effective and efficient method for meeting the indoor air quality requirements of the Taiwan EPA.

  4. [Complex technology for water and wastewater disinfection and its industrial realization in prototype unit].

    Science.gov (United States)

    Arakcheev, E N; Brunman, V E; Brunman, M V; Konyashin, A V; Dyachenko, V A; Petkova, A P

    Usage of complex automated electrolysis unit for drinking water disinfection and wastewater oxidation and coagulation is scoped, its ecological and energy efficiency is shown. Properties of technological process of anolyte production using membrane electrolysis of brine for water disinfection in municipal pipelines and potassium ferrate production using electrochemical dissolution of iron anode in NaOH solution for usage in purification plants are listed. Construction of modules of industrial prototype for anolyte and ferrate production and applied aspects of automation of complex electrolysis unit are proved. Results of approbation of electrolytic potassium ferrate for drinking water disinfection and wastewater, rain water and environmental water oxidation and coagulation are shown.

  5. The placing of the disinfection stage in a reclamation plant to reduce haloform formation

    Energy Technology Data Exchange (ETDEWEB)

    Hart, O O

    1979-10-01

    Chlorination of water containing organic matter leads to the formation of various volatile halogenated hydrocarbons (VHH). Various process configurations of a water reclamation plant were studied to determine the best position of the primary disinfection stage in the plant to achieve the greatest possible reduction of haloform concentration in the water distribution system. The pros and cons of ozone and chlorine as disinfectants were also investigated. Experiment methodology is explained. Results indicate that breakpoint chlorination ahead of two active carbon adsorption stages is the preferred process sequence and disinfectant to assure the lowest possible VHH production in the distribution system. (3 diagrams, 1 drawing, 8 graphs, 54 references, 2 tables)

  6. New Water Disinfection Technology for Earth and Space Applications as Part of the NPP Fellowship Research

    Science.gov (United States)

    SilvestryRodriquez, Nadia

    2010-01-01

    There is the need for a safe, low energy consuming and compact water disinfection technology to maintain water quality for human consumption. The design of the reactor should present no overheating and a constant temperature, with good electrical and optical performance for a UV water treatment system. The study assessed the use of UVA-LEDs to disinfectant water for MS2 Bacteriophage. The log reduction was sufficient to meet US EPA standards as a secondary disinfectant for maintaining water quality control. The study also explored possible inactivation of Pseudomonas aeruginosa and E. coli.

  7. Combined Sewer Overflow pretreatment with chemical coagulation and a particle settler for improved peracetic acid disinfection

    DEFF Research Database (Denmark)

    Chhetri, Ravi Kumar; Bonnerup, Arne; Andersen, Henrik Rasmus

    2016-01-01

    Full scale disinfection by peracetic acid (PAA) was achieved on Combined Sewer Overflow (CSO) water, which was pre-treated physically by a fast settling-filtration unit. Disinfection of untreated CSO water using PAA was compared to treatment using a particle separator (Hydro......Separator®) and additional coagulation with poly-aluminum-chloride. Disinfection for Enterococcus increased with the applied dose of PAA and additional improvement was achieved when it was preceded by chemical coagulation with 5 mg L−1 poly-aluminum-chloride. When Enterococcus was reduced by treatment in the Hydro...

  8. Influence of sublethal concentrations of common disinfectants on expression of virulence genes in Listeria monocytogenes

    DEFF Research Database (Denmark)

    Kastbjerg, Vicky Gaedt; Larsen, M. H.; Gram, Lone

    2010-01-01

    Listeria monocytogenes is a food-borne human pathogen that causes listeriosis, a relatively rare infection with a high fatality rate. The regulation of virulence gene expression is influenced by several environmental factors, and the aim of the present study was to determine how disinfectants use......, such as antibiotic resistance....... by Northern blot analysis. Eleven disinfectants representing four different groups of active components were evaluated in this study. Disinfectants with the same active ingredients had a similar effect on gene expression. Peroxy and chlorine compounds reduced the expression of the virulence genes...

  9. Biofilms and Oxidizing Biocides; Evaluation of Disinfection and Removal Effects by Using Established Microbial Systems.

    Science.gov (United States)

    Tachikawa, Mariko

    2017-01-01

    The formation of bacterial biofilms and their disinfection and removal have been important subjects in the maintenance of water quality in areas such as public spas, swimming pools, food processing lines, industrial water systems, and in the hygienic control of medical devices, hospital procedures, etc. Presented here is an outline of biofilm formation, as well as studies on the disinfection and removal of biofilms by oxidizing biocides using established biofilms. These studies using established biofilms may increase the understanding of the variable response of biofilms to planktonic bacteria, and the unique aspects of oxidizing biocides in the disinfection and removal of biofilms.

  10. Chemical cleaning/disinfection and ageing of organic UF membranes: a review.

    Science.gov (United States)

    Regula, C; Carretier, E; Wyart, Y; Gésan-Guiziou, G; Vincent, A; Boudot, D; Moulin, P

    2014-06-01

    Membrane separation processes have become a basic unit operation for process design and product development. These processes are used in a variety of separation and concentration steps, but in all cases, the membranes must be cleaned regularly to remove both organic and inorganic material deposited on the surface and/or into the membrane bulk. Cleaning/disinfection is a vital step in maintaining the permeability and selectivity of the membrane in order to get the plant to its original capacity, to minimize risks of bacteriological contamination, and to make acceptable products. For this purpose, a large number of chemical cleaning/disinfection agents are commercially available. In general, these cleaning/disinfection agents have to improve the membrane flux to a certain extent. However, they can also cause irreversible damages in membrane properties and performances over the long term. Until now, there is considerably less literature dedicated to membrane ageing than to cleaning/disinfection. The knowledge in cleaning/disinfection efficiency has recently been improved. But in order to develop optimized cleaning/disinfection protocols there still remains a challenge to better understand membrane ageing. In order to compensate for the lack of correlated cleaning/disinfection and ageing data from the literature, this paper investigates cleaning/disinfection efficiencies and ageing damages of organic ultrafiltration membranes. The final aim is to provide less detrimental cleaning/disinfection procedures and to propose some guidelines which should have been taken into consideration in term of membrane ageing studies. To carry out this study, this article will detail the background of cleaning/disinfection and aging membrane topics in a first introductive part. In a second part, key factors and endpoints of cleaning/disinfection and aging membranes will be discussed deeply: the membrane role and the cleaning parameters roles, such as water quality, storing conditions

  11. What must be done to prevent another humidifier disinfectant disaster?

    Directory of Open Access Journals (Sweden)

    Jong-Hyeon Lee

    2016-11-01

    Full Text Available The humidifier disinfectant disaster (HDD was not a simple poisoning accident by biocides, but a singular disaster in history created by chemicals in household products. This disaster was a result of the failure of a system for the management of chemical and product safety. Since the management authority for chemical usage safety is different from those for chemical safety in products, many blind areas for chemical safety management in products still remain. The ‘Act on the Registration and Evaluation, etc. of Chemical Substances (ARECS’ or the new ‘Biocidal Product Act’ must not only address the blind areas in the management system for chemical and product safety, but also prevent a second HDD. To prevent another HDD, an integrated registration, evaluation, and management system for chemicals and consumer products must be incorporated into the ‘ARECS’ as an essential part for chemical safety in consumer products.

  12. Use of peracetic acid in disinfection of wastewater: a review

    Directory of Open Access Journals (Sweden)

    Grasiele Soares Cavallini

    2012-04-01

    Full Text Available The use of peracetic acid (PAA to disinfect the wastewater has been researched for diverse authors, mainly in European countries, where the microbiological standards to release the effluents in water bodies are more severe and the moderation to use chlorine, due to the raising of trihalometanos is recommended. In this perspective, this work presents a compilation of researches applied directly to environmental sanitation, as well as the researches related to chemical characteristics of PAA and its reaction mechanisms. The combination of this information gives a theoretical and practical view of the use of this oxidant, which contributes to continue the researches in this area, aiming to benefit the environment, economy and public health system.

  13. Pulsed high voltage electric discharge disinfection of microbially contaminated liquids.

    Science.gov (United States)

    Anpilov, A M; Barkhudarov, E M; Christofi, N; Kop'ev, V A; Kossyi, I A; Taktakishvili, M I; Zadiraka, Y

    2002-01-01

    To examine the use of a novel multielectrode slipping surface discharge (SSD) treatment system, capable of pulsed plasma discharge directly in water, in killing micro-organisms. Potable water containing Escherichia coli and somatic coliphages was treated with pulsed electric discharges generated by the SSD. The SSD system was highly efficient in the microbial disinfection of water with a low energy utilization (eta approximately 10-4 kW h l-1). The SSD treatment was effective in the destruction of E. coli and its coliphages through the generation of u.v. radiation, ozone and free radicals. The non-thermal treatment method can be used for the eradication of micro-organisms in a range of contaminated liquids, including milk, negating the use of pasteurization. The method utilizes multipoint electric discharges capable of treating large volumes of liquid under static and flowing regimes.

  14. Disinfection Effect of Film Cassettes by Ultraviolet Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Kweon, Dae Cheol; Park, Peom [Ajou Univ., Suwon (Korea, Republic of)

    2001-12-15

    A bacteria infection on film cassette contact surface was examined at the diagnostic radiology department. Studies have demonstrated a bactericidal effect of ultraviolet irradiation, and to assess the contamination level on film cassette contact surface as a predictor of patient prevent from nosocomial infection. The study showed that the laboratory result was identified non-pathologic and pathologic bacterial in the five different cassette size of the contact surface. Film cassettes were exposed to ultraviolet light for 1, 2 and 3 minutes. Ultraviolet light disinfection practices suitable for bacteria. The study concludes that presence of a bacterial infection will prevent a using antiseptic technique on film cassette contact surface. In conclusion, ultraviolet irradiate on film cassette over the surface more than 2 minutes. Ultraviolet dose of 1565 {mu}W {center_dot} s/cm{sup 2}Win in 30 second relative to ultraviolet dose in time.

  15. Disinfection Effect of Film Cassettes by Ultraviolet Irradiation

    International Nuclear Information System (INIS)

    Kweon, Dae Cheol; Park, Peom

    2001-01-01

    A bacteria infection on film cassette contact surface was examined at the diagnostic radiology department. Studies have demonstrated a bactericidal effect of ultraviolet irradiation, and to assess the contamination level on film cassette contact surface as a predictor of patient prevent from nosocomial infection. The study showed that the laboratory result was identified non-pathologic and pathologic bacterial in the five different cassette size of the contact surface. Film cassettes were exposed to ultraviolet light for 1, 2 and 3 minutes. Ultraviolet light disinfection practices suitable for bacteria. The study concludes that presence of a bacterial infection will prevent a using antiseptic technique on film cassette contact surface. In conclusion, ultraviolet irradiate on film cassette over the surface more than 2 minutes. Ultraviolet dose of 1565 μW · s/cm 2 Win in 30 second relative to ultraviolet dose in time

  16. Ultraviolet light in the use of water disinfection

    International Nuclear Information System (INIS)

    Dabbagh, R.

    1999-01-01

    Ultraviolet light is an effective method in the use of water disinfection for swimming pools, potable water and industry required water. For many reasons Ultraviolet light and Ultraviolet compounded with chlorine (Ultraviolet/chlorine) has been brought to attention ed in resent years. In this research, a swimming pool water disinfection was carried out by means of a system with the use of a reactor which was made of stainless steel (SS-304) and with many another standards required. Operation of system was carried out at first in the pilot plant and then installation in essential water treatment integrated. Inactivation of pollution index, E. Coli or Total coliform and Pseudomonas aeroginosa studies with 6000,16000 and 30000 μW.s/cm 2 Ultraviolet dose and then in presence of 0.3,0.6,0.9 and 1.2 mg/1 free chlorine (Ultraviolet/chlorine). In swimming pools minimum free chlorine residual usually is 1.5 mg/1. Optimum Ultraviolet dose was 16000 μW.s/cm 2 attention to 50 percent Ultraviolet absorption ca sued to TSS,TDS and turbidity. In the Ultraviolet/chlorine system suitable rate was 16000μW.s/cm 2 Ultraviolet dose/0.6 mg/1 chlorine in the 2.4 * 10 5 CFU/100 ml for Total coliform and 3600 CFU/100 ml for Pseudomonas aeroginosa. Most probable number (MPN) estimated multiple tube fermentation technique. In this way the flow rate for system indicated about 240 cm 3 /s or 0.9 m 3 /h. The samples polluted for secondary pollution with 54000 CFU/100 ml for E. Coli and 1800 CFU/100ml Pseudomonas aeroginosa. The number of microbes decreased to zero duration after 45 minutes contact time in presence of free chlorine residual in samples. In practical conditions which that disinfectant system was installed in essential water treatment circuit under 1.4 atm hydraulic pressure no growth was seen for pollution index in disinfected water with Ultraviolet in microbial density about 840 CFU/100 ml for Total coliform and 12 CFU/100 ml for pseudomonas aeroginosa. Attention to lower

  17. Ultraviolet light in the use of water disinfection

    International Nuclear Information System (INIS)

    Dabbagh, R.

    1999-01-01

    Ultraviolet light is an effective method in the use of water disinfection for swimming pools, potable water and industry required water. For many reasons UV light and UV compounded with chlorine (UV/chlorine) has been brought to attention in resent years. In this research, a swimming pool water disinfection was carried out by means of a system with the use of a reactor which was made of stainless steel (SS-304) and with many another standards required. Operation of system was carried out at first in the pilot plant and then installation in essential water treatment integrated. Inactivation of pollution index, E. Coli or Total coliform and Pseudomonas aeroginosa studied with 6000,16000 and 30000 μW.s/cm 2 UV dose and then in presence of 0.3,0.6,0.9 and 1.2 mg/1 free chlorine (UV/chlorine). In swimming pools minimum free chlorine residual usually is 1.5 mg/1. Optimum UV dose was 16000 μW.s/cm 2 attention to 50 percent UV absorption caused to TSS,TDS and turbidity. In the UV/chlorine system suitable rate was 16000μW.s/cm 2 UV dose /0.6 mg/1 chlorine in the 2.4 * 10 5 CFU/100 ml for Total coliform and 3600CFU/100 ml for Pseudomonas aeroginosa. Most probable number(MPN) estimated multiple tube fermentation technique. In this way the flow rate for system indicated about 240 cm 3 /s or 0.9 m 3 /h. The samples polluted for secondary pollution with 54000 CFU/100 ml for E.Coli and 1800 CFU/100ml Pseudomonas aeroginosa. The number of microbes decreased to zero duration after 45 minutes contact time in presence of free chlorine residual in samples. In practical conditions which that disinfectant system was installed in essential water treatment circuit under 1.4 atm hydraulic pressure no growth was seen for pollution index in disinfected water with UV in microbial density about 840 CFU/100 ml for Total coliform and 12CFU/100 ml for Pseudomonas aeroginosa. Attention to lower turbidity, TSS and TDS in tap water, higher flow rate about 560 cm 3 /s or 2 m 3 /h acessesed

  18. Ozone Technology for Pathogenic Bacteria of Shrimp (Vibrio sp.) Disinfection

    Science.gov (United States)

    Wulansarie, Ria; Dyah Pita Rengga, Wara; Rustamadji

    2018-03-01

    One of important marine commodities in Indonesia, shrimps are susceptible with Vibrio sp bacteria infection. That infection must be cleared. One of the technologies for disinfecting Vibrio sp. is ozone technology. In this research, Vibrio sp. is a pathogenic bacterium which infects Penaeus vannamei. Ozone technology is applied for threatening Vibrio sp. In this research, ozonation was performed in different pH. Those are neutral, acid (pH=4), and base (pH=9). The sample was water from shrimp embankment from Balai Besar Perikanan Budidaya Air Payau (BBPBAP) located in Jepara. That water was the habitat of Penaeus vannamei shrimp. The brand of ozonator used in this research was “AQUATIC”. The used ozonator in this research had 0,0325 g/hour concentration. The flow rate of sample used in this research was 2 L/minute. The ozonation process was performed in continuous system. A tank, pipe, pump, which was connected with microfilter, flowmeter and ozone generator were the main tools in this research. It used flowmeter and valve to set the flow rate scalable as desired. The first step was the insert of 5 L sample into the receptacle. Then, by using a pump, a sample supplied to the microfilter to be filtered and passed into the flow meter. The flow rate was set to 2 LPM. Furthermore, gas from ozonator passed to the flow for the disinfection of bacteria and then was recycled to the tank and the process run continuously. Samples of the results of ozonation were taken periodically from time 0, 3, 7, 12, 18, 24 to 30 minutes. The samples of the research were analyzed using Total Plate Count (TPC) test in BBPBAP Jepara to determine the number of Vibrio sp. bacteria. The result of this research was the optimal condition for pathogenic bacteria of shrimp (Vibrio sp.) ozonation was in neutral condition.

  19. Industrial Cooling Tower Disinfection Treatment to Prevent Legionella spp.

    Directory of Open Access Journals (Sweden)

    Matteo Iervolino

    2017-09-01

    Full Text Available The contamination of industrial cooling towers has been identified as one cause of legionellosis, but the real risk has been underestimated. Two different disinfection treatments were tested on Legionella colonization in an industrial Cooling Tower System (CTS. Environmental monitoring of Legionella, P. aeruginosa, and a heterotrophic plate count (HPC at 36 °C was performed from June to October 2016. The disinfection procedures adopted were based on hydrogen peroxide (H2O2 and silver salts (Ag+, in addition to an anti-algal treatment, then using hyperclorination as a shock, and then continuous treatment by sodium hypochlorite (NaClO. L. pneumophila serogroup 8 was found at a concentration of 5.06 Log cfu/L after the CTS filling; a shock treatment performed by H2O2/Ag+ produced a rapid increase in contamination up to 6.14 Log cfu/L. The CTS activity was stopped and two subsequent shock treatments were performed using NaClO, followed by continuous hyperclorination. These procedures showed a significant decrease (p < 0.05 in Legionella concentration (1.77 Log cfu/L. The same trend was observed for P. aeruginosa (0.55 Log cfu/100 mL and HPC (1.95 Log cfu/mL at 36 °C. Environmental monitoring and the adoption of maintenance procedures, including anti-scale treatment, and physical, chemical, and microbiological control, ensure the good performance of a CTS, reducing the Legionella risk for public health.

  20. A new silver based composite material for SPA water disinfection.

    Science.gov (United States)

    Tartanson, M A; Soussan, L; Rivallin, M; Chis, C; Penaranda, D; Lapergue, R; Calmels, P; Faur, C

    2014-10-15

    A new composite material based on alumina (Al2O3) modified by two surface nanocoatings - titanium dioxide (TiO2) and silver (Ag) - was studied for spa water disinfection. Regarding the most common microorganisms in bathing waters, two non-pathogenic bacteria Escherichia coli (Gram-negative) and Staphylococcus epidermidis (Gram positive) were selected as surrogates for bacterial contamination. The bactericidal properties of the Al2O3-TiO2-Ag material were demonstrated under various operating conditions encountered in spa water (temperature: 22-37 °C, presence of salt: CaCO3 or CaCl2, high oxygen content, etc.). Total removal of 10(8) CFU mL(-1) of bacteria was obtained in less than 10 min with 16 g L(-1) of material. Best results were observed for both conditions: a temperature of 37 °C and under aerobic condition; this latest favouring Reactive Oxygen Species (ROS) generation. The CaCO3 salt had no impact on the bactericidal activity of the composite material and CaCl2 considerably stabilized the silver desorption from the material surface thanks to the formation of AgCl precipitate. Preliminary tests of the Al2O3-TiO2-Ag bactericidal behaviour in a continuous water flow confirmed that 2 g L(-1) of material eliminated more than 90% of a 2.0 × 10(8) CFU mL(-1) bacterial mixture after one water treatment recycle and reached the disinfection standard recommended by EPA (coliform removal = 6 log) within 22 h. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Ozone Disinfection of Vibrio vulnificus in Shrimp Pond Water

    Science.gov (United States)

    Dyah Pita Rengga, Wara; Cahya Julyta Putri, Echa; Wulansarie, Ria; Suryanto, Agus

    2018-03-01

    One variety of shrimp, L.Vanamei, often uses brackish water during the operation in the shrimp pond. Chlorination and ultraviolet are usually used for disinfection of brackish water. However, it is ineffective and forms sediment in the water distribution. It can be a negative impact on the water quality cause a contamination on the shrimp, so the farmers might have loss of profit because Vibrio vulnificus causes infection and dead on the shrimp. It affects the safety of consumers and should be minimized. The purpose of this study is to reduce the number of V. vulnificus bacteria in the pond water. The water was put in the storage tanks then pumped to filter out the impurities of the water. Furthermore, the water set the flow rate in 1 LPM, 2 LPM, and 3 LPM. After that, the ozone was injected to the water flow to sterilize the V. vulnificus bacteria. Finally, the water was returned to the original tank. The water from the tank was taken through a valve and analyzed in 0, 3, 7, 12, 18, 24, 30 minutes. The sample was analyzed immediately using a Total Plate Count method to determine the number of V. vulnificus bacteria in the shrimp pond water. The flow rate shows that the longer time of ozone made a lower amount of Vibrio v. bacteria. In 2 LPM water, it shows the optimum results of V. vulnificus. bacteria reduction for 88.1% compared to the flow rate of 1 LPM and 3 LPM with the bacteria reduction of 68,8% and 70.6%. This study shows that the ozone with a flow rate of 2 LPM circulation is the most effective method to help reducing the number of V. vulnificus in brackish water distribution system in the shrimp environment and potentially as a disinfectant.

  2. Quantification of air plasma chemistry for surface disinfection

    International Nuclear Information System (INIS)

    Pavlovich, Matthew J; Clark, Douglas S; Graves, David B

    2014-01-01

    Atmospheric-pressure air plasmas, created by a variety of discharges, are promising sources of reactive species for the emerging field of plasma biotechnology because of their convenience and ability to operate at ambient conditions. One biological application of ambient-air plasma is microbial disinfection, and the ability of air plasmas to decontaminate both solid surfaces and liquid volumes has been thoroughly established in the literature. However, the mechanism of disinfection and which reactive species most strongly correlate with antimicrobial effects are still not well understood. We describe quantitative gas-phase measurements of plasma chemistry via infrared spectroscopy in confined volumes, focusing on air plasma generated via surface micro-discharge (SMD). Previously, it has been shown that gaseous chemistry is highly sensitive to operating conditions, and the measurements we describe here extend those findings. We quantify the gaseous concentrations of ozone (O 3 ) and nitrogen oxides (NO and NO 2 , or NO x ) throughout the established ‘regimes’ for SMD air plasma chemistry: the low-power, ozone-dominated mode; the high-power, nitrogen oxides-dominated mode; and the intermediate, unstable transition region. The results presented here are in good agreement with previously published experimental studies of aqueous chemistry and parameterized models of gaseous chemistry. The principal finding of the present study is the correlation of bacterial inactivation on dry surfaces with gaseous chemistry across these time and power regimes. Bacterial decontamination is most effective in ‘NO x mode’ and less effective in ‘ozone mode’, with the weakest antibacterial effects in the transition region. Our results underscore the dynamic nature of air plasma chemistry and the importance of careful chemical characterization of plasma devices intended for biological applications. (paper)

  3. Quantification of air plasma chemistry for surface disinfection

    Science.gov (United States)

    Pavlovich, Matthew J.; Clark, Douglas S.; Graves, David B.

    2014-12-01

    Atmospheric-pressure air plasmas, created by a variety of discharges, are promising sources of reactive species for the emerging field of plasma biotechnology because of their convenience and ability to operate at ambient conditions. One biological application of ambient-air plasma is microbial disinfection, and the ability of air plasmas to decontaminate both solid surfaces and liquid volumes has been thoroughly established in the literature. However, the mechanism of disinfection and which reactive species most strongly correlate with antimicrobial effects are still not well understood. We describe quantitative gas-phase measurements of plasma chemistry via infrared spectroscopy in confined volumes, focusing on air plasma generated via surface micro-discharge (SMD). Previously, it has been shown that gaseous chemistry is highly sensitive to operating conditions, and the measurements we describe here extend those findings. We quantify the gaseous concentrations of ozone (O3) and nitrogen oxides (NO and NO2, or NOx) throughout the established ‘regimes’ for SMD air plasma chemistry: the low-power, ozone-dominated mode; the high-power, nitrogen oxides-dominated mode; and the intermediate, unstable transition region. The results presented here are in good agreement with previously published experimental studies of aqueous chemistry and parameterized models of gaseous chemistry. The principal finding of the present study is the correlation of bacterial inactivation on dry surfaces with gaseous chemistry across these time and power regimes. Bacterial decontamination is most effective in ‘NOx mode’ and less effective in ‘ozone mode’, with the weakest antibacterial effects in the transition region. Our results underscore the dynamic nature of air plasma chemistry and the importance of careful chemical characterization of plasma devices intended for biological applications.

  4. Radiation disinfection of manure for animal feed supplement

    International Nuclear Information System (INIS)

    Harsojo; Andini, S.; Nazly, H.; Suwirma, S.; Danius, J.

    1989-01-01

    Radiation disinfection of manure for animal feed supplement. Radiation treatment for disinfection of manure have been investigated on manure collected during the dry and rainy seasons. Total bacterial counts of non-irradiated dewatered manure with water content of around 13.44% were found to be 1.0x10 6 up to 1.4x10 8 per g during the dry season, and 2.0x10 5 up to 1.7x10 7 per g during the rainy season, while coliforms, enterobecteriacease, staphylococcus, streptococcus, and pseudomonas were found to be 1.0x10 6 up to 1.4x10 8 per g, 1.0x10 4 up to 1.2x10 6 per g, 4.0x10 5 up to 2.2x10 7 per g, 1.8x10 3 per g, and 1.0x10 2 up to 5.4x10 3 per g, respectively. About 30% of the total coliforms were found to be escherichia coli. Irradiation dose of 4 kGy eliminated salmonella from all samples observed. No. Shigella Vibrio, and parasites were detected in the samples. Total nitrogen of the dewatered manure ranged between 1.87 and 2.33%, phosphorus between 1.25 and 4.38%, and potassium between 0.66 and 2.18%. Heavy metal elements were found only in very small amounts, hence the dewatered manure could be applied as animal feed or soil conditioner. A combination of irradiation at 4 kGy and storage for 3 months was synergistically effective to eliminate coliform, E. coli, and salmonella in the dewatered manure. From nutritional point of view, the manure is still acceptable for animal feed supplement. (author). 13 refs

  5. Effect of Different Disinfection Protocols on Microbial and Biofilm Contamination of Dental Unit Waterlines in Community Dental Practices

    Directory of Open Access Journals (Sweden)

    Laura Dallolio

    2014-02-01

    Full Text Available Output water from dental unit waterlines (DUWLs may be a potential source of infection for both dental healthcare staff and patients. This study compared the efficacy of different disinfection methods with regard to the water quality and the presence of biofilm in DUWLs. Five dental units operating in a public dental health care setting were selected. The control dental unit had no disinfection system; two were disinfected intermittently with peracetic acid/hydrogen peroxide 0.26% and two underwent continuous disinfection with hydrogen peroxide/silver ions (0.02% and stabilized chlorine dioxide (0.22%, respectively. After three months of applying the disinfection protocols, continuous disinfection systems were more effective than intermittent systems in reducing the microbial contamination of the water, allowing compliance with the CDC guidelines and the European Council regulatory thresholds for drinking water. P. aeruginosa, Legionella spp, sulphite-reducing Clostridium spores, S. aureus and β-haemolytic streptococci were also absent from units treated with continuous disinfection. The biofilm covering the DUWLs was more extensive, thicker and more friable in the intermittent disinfection dental units than in those with continuous disinfection. Overall, the findings showed that the products used for continuous disinfection of dental unit waterlines showed statistically better results than the intermittent treatment products under the study conditions.

  6. Effect of different disinfection protocols on microbial and biofilm contamination of dental unit waterlines in community dental practices.

    Science.gov (United States)

    Dallolio, Laura; Scuderi, Amalia; Rini, Maria S; Valente, Sabrina; Farruggia, Patrizia; Sabattini, Maria A Bucci; Pasquinelli, Gianandrea; Acacci, Anna; Roncarati, Greta; Leoni, Erica

    2014-02-18

    Output water from dental unit waterlines (DUWLs) may be a potential source of infection for both dental healthcare staff and patients. This study compared the efficacy of different disinfection methods with regard to the water quality and the presence of biofilm in DUWLs. Five dental units operating in a public dental health care setting were selected. The control dental unit had no disinfection system; two were disinfected intermittently with peracetic acid/hydrogen peroxide 0.26% and two underwent continuous disinfection with hydrogen peroxide/silver ions (0.02%) and stabilized chlorine dioxide (0.22%), respectively. After three months of applying the disinfection protocols, continuous disinfection systems were more effective than intermittent systems in reducing the microbial contamination of the water, allowing compliance with the CDC guidelines and the European Council regulatory thresholds for drinking water. P. aeruginosa, Legionella spp, sulphite-reducing Clostridium spores, S. aureus and β-haemolytic streptococci were also absent from units treated with continuous disinfection. The biofilm covering the DUWLs was more extensive, thicker and more friable in the intermittent disinfection dental units than in those with continuous disinfection. Overall, the findings showed that the products used for continuous disinfection of dental unit waterlines showed statistically better results than the intermittent treatment products under the study conditions.

  7. Combined effects of coagulation and adsorption on ultrafiltration membrane fouling control and subsequent disinfection in drinking water treatment.

    Science.gov (United States)

    Xing, Jiajian; Liang, Heng; Cheng, Xiaoxiang; Yang, Haiyan; Xu, Daliang; Gan, Zhendong; Luo, Xinsheng; Zhu, Xuewu; Li, Guibai

    2018-06-02

    This study investigated the combined effects of coagulation and powdered activated carbon (PAC) adsorption on ultrafiltration (UF) membrane fouling control and subsequent disinfection efficiency through filtration performance, dissolved organic carbon (DOC) removal, fluorescence excitation-emission matrix (EEM) spectroscopy, and disinfectant curve. The fouling behavior of UF membrane was comprehensively analyzed especially in terms of pollutant removal and fouling reversibility to understand the mechanism of fouling accumulation and disinfectant dose reduction. Pre-coagulation with or without adsorption both achieved remarkable effect of fouling mitigation and disinfection dose reduction. The two pretreatments were effective in total fouling control and pre-coagulation combined with PAC adsorption even decreased hydraulically irreversible fouling notably. Besides, pre-coagulation decreased residual disinfectant decline due to the removal of hydrophobic components of natural organic matters (NOM). Pre-coagulation combined with adsorption had a synergistic effect on further disinfectant decline rate reduction and decreased total disinfectant consumption due to additional removal of hydrophilic NOM by PAC adsorption. The disinfectant demand was further reduced after membrane. These results show that membrane fouling and disinfectant dose can be reduced in UF coupled with pretreatment, which could lead to the avoidance of excessive operation cost disinfectant dose for drinking water supply.

  8. Solar disinfection of water for low income communities; Desinfeccao solar de agua para comunidades de baixa renda

    Energy Technology Data Exchange (ETDEWEB)

    Felix, Lorna Falcao

    2010-03-15

    The use of solar energy for water disinfection, and is accessible to disadvantaged communities because of its low cost, has the advantage of using disposable materials such as bottles of polyethylene terephthalate (PET). We present a study that used two methods of disinfection: the methodology proposed by the project Solar Water Disinfection (SODIS), which consisted of water disinfection by solar radiation and temperature and the methodology which the temperature of the water for disinfection. In both, we seek to eliminate microorganisms that cause serious diseases such as dysentery, typhoid, cholera, etc. Water samples were collected in the community of Bass, where the population has low income and the incidence of waterborne diseases is high. The experiments were divided into two stages. In step 1 we studied the feasibility of disinfection and in step 2 the feasibility of the pilot plant to obtain adequate levels of disinfection temperatures desired. The results showed the efficiency of the disinfection process, reaching an average of 80 to 100% death of microorganisms, but regrowth was observed in some samples. Finally on the good results of stage 1, is designed and built and tested in an experimental pilot plant, which has shown to be feasible to promote water disinfection through the use of solar energy. The water after treatment is in accordance with the limits established by Brazilian legislation for clean water, maintaining a positive performance for the disinfection and acceptable levels of bacterial regrowth. (author)

  9. Monitoring and control of UV and UV-TiO2 disinfections for municipal wastewater reclamation using artificial neural networks

    International Nuclear Information System (INIS)

    Lin, Chuang-Hung; Yu, Ruey-Fang; Cheng, Wen-Po; Liu, Chun-Ru

    2012-01-01

    Highlights: ► ANN models can effectively control both UV and UV-TiO 2 disinfections for wastewater reuse. ► Comparing to UV disinfection, UV-TiO 2 disinfection can save 13.2–15.7% of UV dosage and capacity. ► SS decreases disinfection efficiency when UV doses were 2 . - Abstract: The use of ultraviolet (UV) irradiation as a physical wastewater disinfection has increased in recent years, especially for wastewater reuse. The UV-TiO 2 can generate OH radicals, which is highly effective to inactivate microorganisms in wastewater disinfection. However, both UV and UV-TiO 2 disinfections create multiple physical, chemical, and bio-chemical phenomena that affect their germicidal efficiency. It is difficult to build a precise control model using existing mathematic models. This study applies artificial neural network (ANN) models to control UV and UV-TiO 2 disinfections. Experimental results indicate that the ANN models, which precisely generate relationships among multiple monitored parameters, total coliform counts in influent and effluent, and UV doses, can be used as control models for UV and UV-TiO 2 disinfections. A novel ANN control strategy is applied to control UV and UV-TiO 2 disinfection processes to meet three total coliform count limits for three wastewater reuse purposes. The proposed controlled strategy effectively controls UV and UV-TiO 2 disinfection, resulting in acceptable total coliform counts in effluent for the three wastewater reuse purposes. The required UV doses for UV-TiO 2 disinfection were lower than those for UV disinfection, resulting in energy saving and capacity reduction of 13.2–15.7%.

  10. ANALYTICAL METHODS FOR WATER DISINFECTION BY-PRODUCTS IN FOODS AND BEVERAGES

    Science.gov (United States)

    The determination of exposure to drinking water disinfection byproducts (DBPs) requires an understanding of how drinking waters come into contact with the human through multiple pathways. The most significant pathway is the ingestion of drinking water. However, ingestion can oc...

  11. Selective Photocatalytic Disinfection by Coupling StrepMiniSog to the Antibody Catalyzed Water Oxidation Pathway.

    Science.gov (United States)

    Wurtzler, Elizabeth M; Wendell, David

    2016-01-01

    For several decades reactive oxygen species have been applied to water quality engineering and efficient disinfection strategies; however, these methods are limited by disinfection byproduct and catalyst-derived toxicity concerns which could be improved by selectively targeting contaminants of interest. Here we present a targeted photocatalytic system based on the fusion protein StrepMiniSOG that uses light within the visible spectrum to produce reactive oxygen species at a greater efficiency than current photosensitizers, allowing for shorter irradiation times from a fully biodegradable photocatalyst. The StrepMiniSOG photodisinfection system is unable to cross cell membranes and like other consumed proteins, can be degraded by endogenous digestive enzymes in the human gut, thereby reducing the consumption risks typically associated with other disinfection agents. We demonstrate specific, multi-log removal of Listeria monocytogenes from a mixed population of bacteria, establishing the StrepMiniSOG disinfection system as a valuable tool for targeted pathogen removal, while maintaining existing microbial biodiversity.

  12. The effect of disinfectant agents on dimensional stability and surface roughness of a tissue conditioner material

    Directory of Open Access Journals (Sweden)

    Amiralireza Khaledi

    2011-01-01

    Conclusion: The results showed that the disinfectant solutions used in this study did not have a significant effect on the surface quality and dimensional accuracy of Visco-gel as a functional impression material.

  13. Evaluation of properties of irreversible hydrocolloid impression materials mixed with disinfectant liquids

    Directory of Open Access Journals (Sweden)

    Arul Amalan

    2013-01-01

    Conclusion: Chlorhexidine solution can be used to mix irreversible hydrocolloid impression materials in regular dental practice as it did not significantly alter the properties. This may ensure effective disinfection of impressions.

  14. Effects of disinfection of combined agar/alginate impressions on the dimensional accuracy of stone casts.

    Science.gov (United States)

    Hiraguchi, Hisako; Nakagawa, Hisami; Kaketani, Masahiro; Hirose, Hideharu; Nishiyama, Minoru

    2007-05-01

    This study investigated the effects of disinfection of combined agar/alginate impressions on the dimensional accuracy of resultant stone casts. Impressions of a master cast designed to simulate an abutment tooth were prepared by combining each of two brands of cartridge-form agar impression materials with an alginate impression material. The impressions were immersed in 1% sodium hypochlorite for 10 minutes or 2% glutaraldehyde for 30 minutes. The remaining impressions were sprayed with these two disinfectants and then stored in sealed bags for 10, 30, 60, and 120 minutes. Stone casts obtained from the non-disinfected impressions were also prepared as control. Changes in diameter of the stone casts were then measured. Results indicated that storage for 10 minutes after spraying with 1% sodium hypochlorite was an appropriate disinfection method for combined agar/alginate impressions, as well as immersion in 1% sodium hypochlorite for 10 minutes.

  15. Baby bottle steam sterilizers for disinfecting home nebulizers inoculated with non-tuberculous mycobacteria.

    Science.gov (United States)

    Towle, D; Callan, D A; Lamprea, C; Murray, T S

    2016-03-01

    Non-tuberculous mycobacteria (NTMb), present in environmental water sources, can contribute to respiratory infection in patients with chronic pulmonary disease. Contaminated nebulizers are a potential source of respiratory infection. Treatment with baby bottle steam sterilizers disinfects home nebulizers inoculated with bacterial pathogens but whether this method works for disinfection of NTMb is unclear. Baby bottle steam sterilization was compared with vigorous water washing for disinfecting home nebulizers inoculated with NTMb mixed with cystic fibrosis sputum. No NTMb was recovered from any nebulizers after steam treatment whereas viable NTMb grew after water washing, demonstrating that steam sterilization effectively disinfects NTMb-inoculated nebulizers. Copyright © 2015 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

  16. Baby bottle steam sterilizers disinfect home nebulizers inoculated with bacterial respiratory pathogens.

    Science.gov (United States)

    Towle, Dana; Callan, Deborah A; Farrel, Patricia A; Egan, Marie E; Murray, Thomas S

    2013-09-01

    Contaminated nebulizers are a potential source of bacterial infection but no single method is universally accepted for disinfection. We hypothesized that baby-bottle steam sterilizers effectively disinfect home nebulizers. Home nebulizers were inoculated with the common CF respiratory pathogens methicillin resistant Staphylococcus aureus, Burkholderia cepacia, Haemophilus influenzae, mucoid and non mucoid Pseudomonas aeruginosa, and Stenotrophomonas maltophilia. The nebulizers were swabbed for bacterial growth, treated with either the AVENT (Philips), the NUK Quick & Ready (Gerber) or DRY-POD (Camera Baby) baby bottle steam sterilizer and reswabbed for bacterial growth. All steam sterilizers were effective at disinfecting all home nebulizers. Viable bacteria were not recovered from any inoculated site after steam treatment, under any conditions tested. Steam treatment is an effective disinfection method. Additional studies are needed to confirm whether these results are applicable to the clinical setting. Copyright © 2012 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.

  17. UV disinfection of injection and drinking water - an accepted method on offshore oil platforms

    International Nuclear Information System (INIS)

    Brunner, H.; Klein, H.P.

    1985-01-01

    Ultraviolet disinfection packages have been developed for the treatment of drinking water and injection water on offshore oil platforms. Large-scale tests with sulphate reducing bacteria out outlined. (Auth.)

  18. Drinking water disinfection by means of ultraviolet radiation. Desinfektion von Trinkwasser durch UV-Bestrahlung

    Energy Technology Data Exchange (ETDEWEB)

    Gelzhaeuser, P; Bewig, F; Holm, K; Kryschi, R; Reich, G; Steuer, W

    1985-01-01

    The book presents all lectures held during a course at Technical Academy Esslingen, on September 10, 1985, on the subject of 'Drinking water disinfection by means of ultraviolet radiation'. The methods hitherto used for disinfection are no longer suitable because of the increasing amounts of organic pollutants found in the untreated water, and because of the necessity to make drinking water disinfection less expensive, non-polluting and thus environmentally compatible. U.V. irradiation is a method allowing technically simple and safe disinfection of the water, and also does not have any effect on the natural taste of the drinking water. The lectures presented discuss all aspects of the method, the equipment, and the performance of irradiation systems in practice.

  19. Peracetic acid as an alternative disinfection technology for wet weather flows.

    Science.gov (United States)

    Coyle, Elizabeth E; Ormsbee, Lindell E; Brion, Gail M

    2014-08-01

    Rain-induced wet weather flows (WWFs) consist of combined sewer overflows, sanitary sewer overflows, and stormwater, all of which introduce pathogens to surface waters when discharged. When people come into contact with the contaminated surface water, these pathogens can be transmitted resulting in severe health problems. As such, WWFs should be disinfected. Traditional disinfection technologies are typically cost-prohibitive, can yield toxic byproducts, and space for facilities is often limited, if available. More cost-effective alternative technologies, requiring less space and producing less harmful byproducts are currently being explored. Peracetic acid (PAA) was investigated as one such alternative and this research has confirmed the feasibility and applicability of using PAA as a disinfectant for WWFs. Peracetic acid doses ranging from 5 mg/L to 15 mg/L over contact times of 2 to 10 minutes were shown to be effective and directly applicable to WWF disinfection.

  20. Wastewater disinfection by peracetic acid: assessment of models for tracking residual measurements and inactivation.

    Science.gov (United States)

    Santoro, Domenico; Gehr, Ronald; Bartrand, Timothy A; Liberti, Lorenzo; Notarnicola, Michele; Dell'Erba, Adele; Falsanisi, Dario; Haas, Charles N

    2007-07-01

    With its potential for low (if any) disinfection byproduct formation and easy retrofit for chlorine contactors, peracetic acid (PAA) or use of PAA in combination with other disinfectant technologies may be an attractive alternative to chlorine-based disinfection. Examples of systems that might benefit from use of PAA are water reuse schemes or plants discharging to sensitive receiving water bodies. Though PAA is in use in numerous wastewater treatment plants in Europe, its chemical kinetics, microbial inactivation rates, and mode of action against microorganisms are not thoroughly understood. This paper presents results from experimental studies of PAA demand, PAA decay, and microbial inactivation, with a complementary modeling analysis. Model results are used to evaluate techniques for measurement of PAA concentration and to develop hypotheses regarding the mode of action of PAA in bacterial inactivation. Kinetic and microbial inactivation rate data were collected for typical wastewaters and may be useful for engineers in evaluating whether to convert from chlorine to PAA disinfection.

  1. Use of Disinfectants and Sanitizers in Heating, Ventilation, Air Conditioning, and Refrigeration Systems

    Science.gov (United States)

    This letter is to brings attention several concerns that the Agency has regarding the use of sanitizer and/or disinfectant products, and other types of antimicrobial products, to treat the surfaces of heating, ventilation

  2. Study of sequential disinfection for the inactivation of protozoa and indicator microorganisms in wastewater

    Directory of Open Access Journals (Sweden)

    Raphael Corrêa Medeiros

    2015-05-01

    Full Text Available Sewage disinfection has the primary objective of inactivating pathogenic organisms to prevent the dissemination of waterborne diseases. This study analyzed individual disinfection, with chlorine and ultraviolet radiation, and sequential disinfection (chlorine-UV radiation. The tests were conducted with anaerobic effluent in batch, in laboratory scale, with two dosages of chlorine (10 and 20 mg L-1 and UV (2.5 and 6.1 Wh m-3. In addition, to guarantee the presence of cysts in the tests, 104 cysts per liter of Giardia spp. were inoculated. The resistance order was as follows: E. coli = Total Coliforms < Clostridium perfringens < Giardia spp.. Furthermore, synergistic effects reached 0.06 to 1.42 log of inactivation in sequential disinfection for both the most resistant microorganisms.

  3. [Survey of synthetic disinfectants in grapefruit seed extract and its compounded products].

    Science.gov (United States)

    Sugimoto, Naoki; Tada, Atsuko; Kuroyanagi, Masanori; Yoneda, Yuko; Yun, Young Sook; Kunugi, Akira; Sato, Kyoko; Yamazaki, Takeshi; Tanamoto, Ken-Ichi

    2008-02-01

    Grapefruit seed extract (GSE), derived from the seeds of grapefruit (Citrus paradisi MCAF.), is listed as a natural food additive in Japan. Products containing GSE are used as disinfectants made from only natural sources, especially after Japanese researchers found that GSE prevents the growth of norovirus. On the other hand, recent overseas studies indicated that synthetic disinfectants, such as benzalkonium and benzethonium chlorides, were present in some commercial GSE products. To confirm the quality of commercial GSE products available in Japanese markets, we carried out comprehensive research to identify the major constituents of commercial GSE products which are used as food additives (13 products from 6 manufacturers), dietary supplements (5 products from 4 manufacturers), cosmetic materials (16 products from 10 manufacturers) and disinfectant or deodorant sprays (7 products from 7 manufacturers). By means of NMR and LC/MS analysis, synthetic disinfectants such as benzethonium or benzalkonium salts were detected in most of the commercial GSE products.

  4. Antimicrobial Products Registered for Disinfection Use against Avian Influenza on Poultry Farms and Other Facilities

    Science.gov (United States)

    EPA registers disinfectants against Avian Influenza A. Although there are no antimicrobial products registered for the H5N2 subtype of Avian Influenza A virus, based on available scientific information these products will work against other HPAI strains.

  5. Characterization of a stirred tank electrochemical cell for water disinfection processes

    International Nuclear Information System (INIS)

    Polcaro, A.M.; Vacca, A.; Mascia, M.; Palmas, S.; Pompei, R.; Laconi, S.

    2007-01-01

    Laboratory experiments were performed to characterize the behaviour of an electrochemical cell equipped with boron-doped diamond anodes and to verify its effectiveness in water disinfection. The hydrodynamic regime was determined when the cell worked either in batch or in continuous mode. Galvanostatic electrolyses of aqueous 1 mM Na 2 SO 4 solutions were performed to investigate on the oxidant production in different experimental conditions. The same solutions contaminated by E. coli, enterococci and coliforms were used as test media to verify the effectiveness of the system in the disinfection process. Experimental results indicated that the major inactivation mechanism of bacteria in the electrochemical cell is a disinfection by electrochemically generated oxidants, however a cooperative effect of superficial reaction has to be taken into account. The great capability of BDD anode to produce reactive oxygen species (ROS) and other oxidizing species during the electrolysis allows to establish a chlorine-free disinfection process

  6. Electrochemically activated water as an alternative to chlorine for decentralized disinfection

    KAUST Repository

    Ghebremichael, Kebreab A.; Muchelemba, E.; Petruševski, Branislav; Amy, Gary L.

    2011-01-01

    Electrochemically activated (ECA) water is being extensively studied and considered as an alternative to chlorine for disinfection. Some researchers claim that ECA is by and large a chlorine solution, while others claim the presence of reactive

  7. Chlorine dioxide as a disinfectant for Ralstonia solanacearum control in water, storage and equipment

    Directory of Open Access Journals (Sweden)

    Popović Tatjana

    2016-01-01

    Full Text Available Brown rot or bacterial wilt caused by bacterium Ralstonia solanacearum is the main limiting factor in potato production. Quarantine measures are necessary to avoid spread of disease to disease-free areas. R. solanacearum has been shown to contaminate watercourses from which crop irrigation is then prohibited causing further potential losses in yield and quality. The bacteria also spread via surfaces that diseased seed potatoes come into contact with. This study showed bactericidal activity of chlorine dioxide (CIO2 on R. solanacearum for disinfection of water, surface and equipment. The results showed that CIO2 solution at concentration of 2 ppm at 30 minutes of exposure time had bactericidal effect for disinfection of water. For surface and equipment disinfection, concentration of 50 ppm showed total efficacy at 30 min and 5 sec exposure time, respectively. Results suggest that use of CIO2 as a disinfectant has a potential for control of brown rot pathogen in water, storage and equipment.

  8. Risk of viral acute gastrointestinal illness from non-disinfected drinking water distribution systems

    Science.gov (United States)

    Acute gastrointestinal illness (AGI) resulting from pathogens directly entering the piping of drinking water distribution systems is insufficiently understood. Here, we estimate AGI incidence attributable to virus intrusions into non-disinfecting municipal distribution systems. Viruses were enumerat...

  9. 9 CFR 96.10 - Uncertified casings; transportation for disinfection; original shipping containers; disposition...

    Science.gov (United States)

    2010-01-01

    ... United States without certification may be forwarded in customs custody to a USDA-approved facility for disinfection under APHIS supervision and release by the United States Customs authorities, provided that...

  10. Characterization of engineered nanoparticles in commercially available spray disinfectant products advertised to contain colloidal silver

    Science.gov (United States)

    Given the potential for human exposure to silver nanoparticles from spray disinfectants and dietary supplements, we characterized the silver-containing nanoparticles in 22 commercial products that advertised the use of silver or colloidal silver as the active ingredient. Characte...

  11. Role of ultraviolet (UV) disinfection in infection control and environmental cleaning.

    Science.gov (United States)

    Qureshi, Zubair; Yassin, Mohamed H

    2013-06-01

    Ultraviolet (UV) radiation is capable of disinfecting surfaces, water and air. The UV technology was used for many years. However, safer and more effective delivery systems of UV radiation, make it a very useful option for disinfection. Effective disinfection of environmental surfaces is a key step in the prevention of spread of infectious agents. The traditional manual cleaning is essential in assuring adequate elimination of contamination. However, terminal cleaning is frequently suboptimal or unpredictable in many circumstances. UV-C radiation is an adjunctive disinfectant new technology that could kill a wide array of microorganisms including both vegetative and spore forming pathogens. The technology is getting more affordable and has produced consistent reproducible significant reduction of bacterial contamination.

  12. An overview of water disinfection in developing countries and the potential for solar thermal water pasteurization

    Energy Technology Data Exchange (ETDEWEB)

    Burch, J.; Thomas, K.E.

    1998-01-01

    This study originated within the Solar Buildings Program at the U.S. Department of Energy. Its goal is to assess the potential for solar thermal water disinfection in developing countries. In order to assess solar thermal potential, the alternatives must be clearly understood and compared. The objectives of the study are to: (a) characterize the developing world disinfection needs and market; (b) identify competing technologies, both traditional and emerging; (c) analyze and characterize solar thermal pasteurization; (d) compare technologies on cost-effectiveness and appropriateness; and (e) identify research opportunities. Natural consequences of the study beyond these objectives include a broad knowledge of water disinfection problems and technologies, introduction of solar thermal pasteurization technologies to a broad audience, and general identification of disinfection opportunities for renewable technologies.

  13. Divergent opinions on surface disinfection: myths or prevention? A review of the literature

    OpenAIRE

    Exner, Martin

    2007-01-01

    Virtually no prevention strategy in hospital hygiene has been the focus of such frequent controversial discussions as the role of surface disinfection. Set against that background, the Commission for Hospital Hygiene and Infection Prevention at the Robert Koch Institute founded a working group comprising members with divergent views of risk evaluation as regards the role of disinfection. This working group produced a most carefully drafted guideline on how to deal with various risk areas and ...

  14. Determination of Decimal Reduction Time of Peracetic Acid Used in Brewery Industry for Disinfection Purposes

    OpenAIRE

    , N. Lajçi; , X. Lajçi; , B. Baruti

    2016-01-01

    Disinfection operation is of great importance within the beer processing industry for beer safety reasons. Microbiological risk management is essential in the production of high-quality beer since quality defects may lead to substantial economic losses. The objective of this research was to investigate the effect of commercial peracetic acid (PAA) concentration for disinfection and the resistance of microorganisms in beer based on the decimal reduction time (D-value), and reduction 6-log10 of...

  15. Disinfection Contact Time study plan (100-N Area tracer protocol). Revision 1

    International Nuclear Information System (INIS)

    Kretzschmar, S.P.; Bedi, G.S.; Martinez, P.; Ervin, K.

    1996-07-01

    Bechtel Hanford, Inc. will prepare an Engineering Tracer Study Protocol for the determination of contact time for the disinfection process at Group A Non-transient Non-community water treatment plant for the 100-N Water Plant at the Hanford Site in Richland, Washington. Included in this report are the results of a study that determine the actual detention time within the plant clearwell, and thus the disinfection contact time at several clearwell effluent flow rates

  16. Improving safety of personnel exposed to disinfectants by introducing an Endoscopy Quality Assurance Program

    OpenAIRE

    Ahmed Gado; Basel Ebeid; Aida Abdelmohsen; Anthony Axon

    2014-01-01

    Background: Chemical disinfection is the most commonly used method in gastrointestinal endoscopy reprocessing. The main problem with chemical disinfection is that it is potentially harmful to humans. Risk assessment of employees using toxic substances is recommended and the control of exposure to these substances is required. In 2003, an endoscopy quality-assurance program was instituted in a secondary care governmental hospital in Egypt. Aim: The aim of the study was to assess the risk to...

  17. Vitality of Enterococcus faecalis inside dentinal tubules after five root canal disinfection methods

    OpenAIRE

    Vatkar, Niranjan Ashok; Hegde, Vivek; Sathe, Sucheta

    2016-01-01

    Aim: To compare the vitality of Enterococcus faecalis within dentinal tubules after subjected to five root canal disinfection methods. Materials and Methods: Dentin blocks (n = 60) were colonized with E. faecalis. After 4 weeks of incubation, the dentin blocks were divided into one control and five test groups (n = 10 each). The root canals of test groups were subjected to one of the disinfection methods, namely, normal saline (NS), sodium hypochlorite (NaOCl), chlorhexidine digluconate (C...

  18. A practical demonstration of water disinfection using TiO2 films and sunlight.

    Science.gov (United States)

    Gelover, Silvia; Gómez, Luis A; Reyes, Karina; Teresa Leal, Ma

    2006-10-01

    The scope of this study is the assessment of the efficiency of solar disinfection by heterogeneous photocatalysis with sol-gel immobilized (titanium dioxide) TiO2 films over glass cylinders. The solar disinfection process known as SODIS was considered as a reference. Spring water naturally polluted with coliform bacteria was exposed to sunlight in plastic bottles with and without TiO2 over simple solar collectors and the disinfection effectiveness was measured. Total and fecal coliforms quantification was performed by means of the chromogenic substrate method in order to obtain the efficiency of each disinfection treatment. The disinfection with TiO2 was more efficient than the SODIS process, inactivating total coliforms as well as fecal coliforms. On a sunny day (more than 1000 W m(-2) irradiance), it took the disinfection with immobilized TiO2 15 min of irradiation to inactivate the fecal coliforms to make them undetectable. For inactivation of total coliforms, 30 min was required, so that in less than half the time it takes SODIS, the treated water complies with the microbial standards for drinking water in Mexico. Another important part of this study has been to determine the bacterial regrowth in water after the disinfection processes were tested. After SODIS, bacterial regrowth of coliforms was observed. In contrast, when using the TiO2 catalyst, coliforms regrowth was not detected, neither for total nor for fecal coliforms. The disinfection process using TiO2 kept treated water free of coliforms at least for seven days after sun irradiation. This demonstration opens the possibility of application of this simple method in rural areas of developing countries.

  19. Efficacy of chemical disinfectants for the containment of the salamander chytrid fungus Batrachochytrium salamandrivorans

    OpenAIRE

    Van Rooij, Pascale; Pasmans, Frank; Coen, Yanaïka; Martel, An

    2017-01-01

    The recently emerged chytrid fungus Batrachochytrium salamandrivorans (Bsal) causes European salamander declines. Proper hygiene protocols including disinfection procedures are crucial to prevent disease transmission. Here, the efficacy of chemical disinfectants in killing Bsal was evaluated. At all tested conditions, Biocidal (R), Chloramine-T (R), Dettol medical (R), Disolol (R), ethanol, F10 (R), Hibiscrub (R), potassium permanganate, Safe4 (R), sodium hypochlorite, and Virkon S (R), were ...

  20. Chemical disinfection of non-porous inanimate surfaces experimentally contaminated with four human pathogenic viruses.

    OpenAIRE

    Sattar, S. A.; Springthorpe, V. S.; Karim, Y.; Loro, P.

    1989-01-01

    The chemical disinfection of virus-contaminated non-porous inanimate surfaces was investigated using coxsackievirus B3, adenovirus type 5, parainfluenza virus type 3 and coronavirus 229E as representatives of important nosocomial viral pathogens. A 10 microliter amount of the test virus, suspended in either faeces or mucin, was placed onto each stainless steel disk (about 1 cm in diameter) and the inoculum allowed to dry for 1 h under ambient conditions. Sixteen disinfectant formulations were...

  1. Comparative Study of Antibacterial and Antifungal Effects of Rigid Gas Permeable Contact Lens Disinfecting Solutions

    OpenAIRE

    Kuzman, Tomislav; Barišić Kutija, Marija; Kordić, Rajko; Popović Suić, Smiljka; Jandroković, Sonja; Škegro, Ivan; Pokupec, Rajko

    2013-01-01

    The aim of this study was to compare antimicrobial efficacy of rigid contact lens disinfecting solutions. We tested five commercially available solutions: Unique pH (Alcon Laboratories), Boston Advance (Polymer Technology Corp.), Nitilens Conditioner GP (Avizor), Total Care (AMO), Boston Simplus (Bausch&Lomb). Their efficacy to disinfect saline solution experimentally contaminated with American Type Culture Collection (ATCC): Staphylococcus aureus (ATCC 25923), Escherichia coli (ATCC 25922...

  2. Effectiveness of Surface Cleaning and Disinfection in a Brazilian Healthcare Facility

    Science.gov (United States)

    Santos-Junior, Aires G.; Ferreira, Adriano M.; Frota, Oleci P.; Rigotti, Marcelo A.; Barcelos, Larissa da S.; Lopes de Sousa, Alvaro Francisco; de Andrade, Denise; Guerra, Odanir G.; R. Furlan, Mara C.

    2018-01-01

    Background: Failures in the processes of cleaning and disinfecting health service surfaces may result in the spread and transfer of pathogens that are often associated with healthcare-related infections and outbreaks. Aims: To assess the effectiveness of environmental surface cleaning and disinfection in a hospital clinic. Method: The study was conducted in a nursing ward with 45 beds. A total of 80 samples from five high-touch surfaces were evaluated before and after cleaning and disinfection, using the following methods: visual inspection, adenosine triphosphate bioluminescence assay, aerobic colony count, Staphylococcus aureus colony count, and evaluation of resistance to methicillin. The data analysis used nonparametric comparative and correlative tests to observe any differences in the pre- and post- cleaning and disinfection results for the surfaces assessed. Results: Effective cleaning and disinfection had a significant effect on only two surfaces when measured for the presence of adenosine triphosphate, the inner bathroom door handle (p=0.007) and the toilet bowl (p=0.01). When evaluated for Staphylococcus aureus colony count, the toilet flush handle also demonstrated a significant effect (p=0.04). Conclusion: The effectiveness of cleaning and disinfection of the surfaces tested was not satisfactory. An educational intervention is recommended for the cleaning and disinfection staff and the nursing team at the healthcare facility. Relevance to Clinical Practice: The data in the study revealed that daily hospital cleaning and disinfection in the sampled sites are not sufficient in medical and surgical wards. Hospital cleanliness must be reevaluated from the point of view of materials, such as an adequate supply of clean cloths, in addition to establishing more precise cleanliness protocols and accurate monitoring systems. PMID:29643951

  3. Efficacy of Cleaning and Disinfection Procedures in a Zebrafish (Danio rerio) Facility

    OpenAIRE

    Garcia, Rachel L; Sanders, George E

    2011-01-01

    Appropriate cleaning and disinfection procedures in zebrafish (Danio rerio) laboratories are crucial in preventing the spread of aquatic animal pathogens and minimizing the build-up of waste products and biologic matter. The procedures selected should accomplish these goals and incorporate the individual needs of various laboratories. In this study of a single zebrafish facility, we assessed the efficacy of 2 different cleaning and disinfection procedures for nets, tanks, and lids. ATP levels...

  4. Effectiveness of Surface Cleaning and Disinfection in a Brazilian Healthcare Facility.

    Science.gov (United States)

    Santos-Junior, Aires G; Ferreira, Adriano M; Frota, Oleci P; Rigotti, Marcelo A; Barcelos, Larissa da S; Lopes de Sousa, Alvaro Francisco; de Andrade, Denise; Guerra, Odanir G; R Furlan, Mara C

    2018-01-01

    Failures in the processes of cleaning and disinfecting health service surfaces may result in the spread and transfer of pathogens that are often associated with healthcare-related infections and outbreaks. To assess the effectiveness of environmental surface cleaning and disinfection in a hospital clinic. The study was conducted in a nursing ward with 45 beds. A total of 80 samples from five high-touch surfaces were evaluated before and after cleaning and disinfection, using the following methods: visual inspection, adenosine triphosphate bioluminescence assay, aerobic colony count, Staphylococcus aureus colony count, and evaluation of resistance to methicillin. The data analysis used nonparametric comparative and correlative tests to observe any differences in the pre- and post- cleaning and disinfection results for the surfaces assessed. Effective cleaning and disinfection had a significant effect on only two surfaces when measured for the presence of adenosine triphosphate, the inner bathroom door handle ( p =0.007) and the toilet bowl ( p =0.01). When evaluated for Staphylococcus aureus colony count, the toilet flush handle also demonstrated a significant effect ( p =0.04). The effectiveness of cleaning and disinfection of the surfaces tested was not satisfactory. An educational intervention is recommended for the cleaning and disinfection staff and the nursing team at the healthcare facility. The data in the study revealed that daily hospital cleaning and disinfection in the sampled sites are not sufficient in medical and surgical wards. Hospital cleanliness must be reevaluated from the point of view of materials, such as an adequate supply of clean cloths, in addition to establishing more precise cleanliness protocols and accurate monitoring systems.

  5. Comparative evaluation of dimensional stability of impression materials from developing countries and developed countries after disinfection with different immersion disinfectant systems and ultraviolet chamber

    Directory of Open Access Journals (Sweden)

    Rupandeep Kaur Samra

    2018-04-01

    Full Text Available Objectives: It was to analyse and compare the effect of different disinfectant systems on the dimensional stability of commonly used irreversible hydrocolloid and addition silicone impression materials from developing countries as compared to materials from developed countries. Material and methods: Disinfectant systems used were glutaraldehyde, sodium hypochlorite and ultraviolet chamber. The stability after disinfection of commonly used alginate and addition silicone of native origin (Algin-Gum & Ad-Sil was compared with similar impression materials from developed countries (Vignette and Aquasil and results compared. A CAD/CAM manufactured stainless steel die simulating maxilla with four metal studs at canine and molar region was used. Impressions were made and disinfected after rinsing and drying and casts poured. The cross arch distance, interabutment distance and the occluso-gingival length of the studs was measured under traveling microscope and observations were recorded and compared. ANOVA test and Bonferroni test was applied. Results: An increase in the interabutment and cross arch distance and decrease in occluso-gingival height was seen in the casts obtained. Glutaraldehyde immersion showed variation in the interabutment and cross arch distance for all materials studied. Ultraviolet chamber and sodium hypochlorite produced best results. Dimensional stability of impression materials like Vignette, Algin-Gum & Aquasil was found to within clinically acceptable limits after disinfection while maximum deviation was seen with Algin-Gum. Conclusion: Evaluated materials can be safely disinfected with sodium hypochlorite and ultraviolet chamber. Addition silicone of native origin is at par with impression materials from developed countries but same cannot be said about alginate. Keywords: Dimensional stability, Immersion systems, Ultraviolet chamber, Addition silicone, Alginate, Sodium hypochlorite, Glutaraldehyde

  6. Comparative susceptibility of Salmonella Typhimurium biofilms of different ages to disinfectants.

    Science.gov (United States)

    Wong, Hui San; Townsend, Kirsty M; Fenwick, Stan G; Maker, Garth; Trengove, Robert D; O'Handley, Ryan M

    2010-10-01

    There is a general consensus that with increasing age a biofilm shows increased resistance to antimicrobials. In this study the susceptibility of 3-, 5- and 7-day-old Salmonella enterica serovar Typhimurium biofilms to disinfectants was evaluated. It was hypothesized that 7-day-old biofilms would be more resistant to disinfectants compared to 3- and 5-day-old biofilms. Biofilms were formed using the MBEC™ system and treated with six chemical disinfectants for 1 and 5 min. Four disinfectants at the highest concentration available showed 100% reduction in viable cells from all ages of biofilms after exposure for 5 min, and ethanol at 70% v/v was the least effective against biofilms, followed by chlorhexidine gluconate (CG). At the recommended user concentrations, only sodium hypochlorite showed 100% reduction in viable cells from all ages of biofilms. Benzalkonium chloride and CG were the least effective against biofilms, followed by quaternary ammonium compound which only showed 100% reduction in viable cells from 5-day-old biofilms. Overall, the results from this study do not display enhanced resistance in 7-day-old biofilms compared to 3- and 5-day-old biofilms. It is concluded that under the conditions of this study, the age of biofilm did not contribute to resistance towards disinfectants. Rather, the concentration of disinfectant and an increased contact time were both shown to play a role in successful sanitization.

  7. Disinfection of a probe used in ultrasound-guided prostate biopsy.

    Science.gov (United States)

    Rutala, William A; Gergen, Maria F; Weber, David J

    2007-08-01

    Transrectal ultrasound (TRUS)-guided prostate biopsies are among the most common outpatient diagnostic procedures in urology clinics and carry the risk of introducing pathogens that may lead to infection. To investigate the effectiveness of procedures for disinfecting a probe used in ultrasound-guided prostate biopsy. The effectiveness of disinfection was determined by inoculating 10(7) colony forming units (cfu) of Pseudomonas aeruginosa at the following 3 sites on the probe: the interior lumen of the biopsy needle guide, the outside surface of the biopsy needle guide, and the interior lumen of the ultrasound probe where the needle guide passes through the transducer. Each site was investigated separately. After inoculation, the probe was immersed in 2% glutaraldehyde for 20 minutes and then assessed for the level of microbial contamination. The results demonstrated that disinfection (ie, a reduction in bacterial load of greater than 7 log(10) cfu) could be achieved if the needle guide was removed from the probe. However, if the needle guide was left in the probe channel during immersion in 2% glutaraldehyde, disinfection was not achieved (ie, the reduction was approximately 1 log(10) cfu). Recommendations for probe disinfection are provided and include disassembling the device and immersing the probe and the needle guide separately in a high-level disinfectant.

  8. Color stability of maxillofacial silicone with nanoparticle pigment and opacifier submitted to disinfection and artificial aging.

    Science.gov (United States)

    Filié Haddad, Marcela; Coelho Goiato, Marcelo; Micheline Dos Santos, Daniela; Moreno, Amália; Filipe D'almeida, Nuno; Alves Pesqueira, Aldiéris

    2011-09-01

    The purpose of this study was to evaluate the color stability of a maxillofacial elastomer with the addition of a nanoparticle pigment and∕or an opacifier submitted to chemical disinfection and artificial aging. Specimens were divided into four groups (n = 30): group I: silicone without pigment or opacifier, group II: ceramic powder pigment, group III: Barium sulfate (BaSO(4)) opacifier, and group IV: ceramic powder and BaSO(4) opacifier. Specimens of each group (n = 10) were disinfected with effervescent tablets, neutral soap, or 4% chlorhexidine gluconate. Disinfection was done three times a week during two months. Afterward, specimens were submitted to different periods of artificial aging. Color evaluation was initially done, after 60 days (disinfection period) and after 252, 504, and 1008 h of artificial aging with aid of a reflection spectrophotometer. Data were analyzed by three-way ANOVA and Tukey test (α = 0.05). The isolated factor disinfection did not statistically influence the values of color stability among groups. The association between pigment and BaSO(4) opacifier (GIV) was more stable in relationship to color change (△E). All values of △E obtained, independent of the disinfectant and the period of artificial aging, were considered acceptable in agreement with the norms presented in literature.

  9. Determination of several common disinfection by-products in frozen foods.

    Science.gov (United States)

    Cardador, Maria Jose; Gallego, Mercedes

    2018-01-01

    Disinfected water and/or disinfectants are commonly used by the freezing industry in such processes as sanitising, washing, blanching, cooling and transporting the final product. For this reason, disinfection by-products (DBPs) can be expected in frozen foods. This study focused on the presence of DBPs in a wide variety of frozen vegetables, meats and fish. For this purpose, the 14 halogenated DBPs more prevalent in disinfected water were selected (four trihalomethanes, seven haloacetic acids, two haloacetonitriles and trichloronitromethane). Up to seven DBPs were found in vegetables, whereas only four DBPs were present in meats and fish, and at lower concentrations, since their contact with disinfected water is lower than in frozen vegetables. It is important to emphasise that trichloronitromethane (the most abundant nitrogenous DBP in disinfected water) was found for the first time in foods. Finally, it was concluded that the freezing process can keep the compounds stable longer than other preservation processes (viz. sanitising, canning) and, therefore, frozen foods present higher DBP concentrations than other food categories (minimally processed vegetables, or canned vegetables and meats).

  10. Comparison of different techniques for disinfection of teeth internal space in preclinical teaching

    Directory of Open Access Journals (Sweden)

    Tabrizizadeh M.

    2009-12-01

    Full Text Available "nBackground and Aim: Extracted teeth used in preclinic should be disinfected. The aim of this study was to evaluate the effects of some disinfectants on microorganisms cultured from pulp chamber of extracted teeth."nMaterials and Methods: In this experimental study 54 intact human teeth were collected. After access cavity preparation, 10 8 B. streothermophillus endospors were inoculated into pulp chamber. Then cavities were sealed with a temporary restorative material. Teeth were divided into 5 groups of 10 each. The teeth were then stored in these disinfectants: 5.25% hypochlorite sodium, 5% Microten, 5% Deconex, 2% Glutaraldehyd, and 10% Formalin for 48 hours. Two teeth were autoclaved as negative controls and two were stored in normal saline as positive controls. The teeth were then sectioned in cervical area and cultured in Trypticase Soy Broth. After three days turbidity in tubes was evaluated. Statistical analysis was done by Fisher's exact test."nResults: None of these solutions were able to prevent microorganism growth in all samples; however, Formalin was better in six cases than that of other disinfectants. Differences between these five groups were not statistically significant (P=0.384."nConclusion: Sterilization of the teeth with autoclave is the only absolute method for disinfecting the root canals of extracted teeth and disinfectants are not reliable for this purpose.

  11. Influence of disinfectant solutions on test materials used for the determination of masticatory performance

    Directory of Open Access Journals (Sweden)

    Simone Silvério Campos

    2013-06-01

    Full Text Available Masticatory function can be evaluated objectively as the capacity of an individual to fragment solid food after a fixed number of chewing cycles, the so-called masticatory performance (MP. The objective of this study was to evaluate the reliability of four different test materials (Optosil, Optocal, Zetapuls, and Perfil and five disinfection protocols by aspersion and immersion (no disinfection, 2% glutaraldehyde, 2% chlorhexidine, 5.25% sodium hypochlorite, and 70% alcohol on the MP, determined at three moments (24 hours, 15 and 60 days after storing the fragmented blocks. MP was evaluated by calculating X50 through the sieving technique and the Rosim-Ramler equation. The weight and microbiologic count (colony forming units, CFUs of chewed blocks were measured to identify any variations that would make MP determination unfeasible. Differences in MP were observed among the materials (p 0.05. The time and disinfection type had no influence on MP (p > 0.05. The number of CFUs differed between the nondisinfected group and all other disinfection groups at all time points (p < 0.01. No other significant difference in CFU count between disinfection groups was observed. In conclusion, disinfection did not alter the reliability of the test materials for the MP calculation for up to 60 days.

  12. Disinfection protocols for necropsy equipment in rabies laboratories: Safety of personnel and diagnostic outcome.

    Science.gov (United States)

    Aiello, Roberta; Zecchin, Barbara; Tiozzo Caenazzo, Silvia; Cattoli, Giovanni; De Benedictis, Paola

    2016-08-01

    In the last decades, molecular techniques have gradually been adopted for the rapid confirmation of results obtained through gold standard methods. However, international organisations discourage their use in routine laboratory investigations for rabies post-mortem diagnosis, as they may lead to false positive results due to cross-contamination. Cleaning and disinfection are essential to prevent cross-contamination of samples in the laboratory environment. The present study evaluated the efficacy of selected disinfectants on rabies-contaminated necropsy equipment under organic challenge using a carrier-based test. The occurrence of detectable Rabies virus (RABV) antigen, viable virus and RNA was assessed through the gold standard Fluorescent Antibody Test, the Rabies Tissue Culture Infection Test and molecular techniques, respectively. None of the tested disinfectants proved to be effective under label conditions. Off label disinfection protocols were found effective for oxidizing agents and phenolic, only. Biguanide and quaternary ammonium compound were both ineffective under all tested conditions. Overall, discordant results were obtained when different diagnostic tests were compared, which means that in the presence of organic contamination common disinfectants may not be effective enough on viable RABV or RNA. Our results indicate that an effective disinfection protocol should be carefully validated to guarantee staff safety and reliability of results. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  13. Formation of nitrosodimethylamine (NDMA) during chlorine disinfection of wastewater effluents prior to use in irrigation systems.

    Science.gov (United States)

    Pehlivanoglu-Mantas, Elif; Hawley, Elisabeth L; Deeb, Rula A; Sedlak, David L

    2006-01-01

    The probable human carcinogen nitrosodimethylamine (NDMA) is produced when wastewater effluent is disinfected with chlorine. In systems where wastewater effluent is used for landscape or crop irrigation, relatively high chlorine doses (i.e., up to 2,000,mg-min/L) are often used to ensure adequate disinfection and to minimize biofouling in the irrigation system. To assess the formation of NDMA in such systems, samples were collected from several locations in full-scale wastewater treatment systems and their associated irrigation systems. Up to 460 ng/L of NDMA was produced in full-scale systems in which chloramines were formed when wastewater effluent was disinfected with chlorine in the presence of ammonia. Less than 20 ng/L of NDMA was produced in systems that used free chlorine (i.e., HOCl/OCl(-)) for disinfection in the absence of ammonia. The production of NDMA in ammonia-containing systems was correlated with the concentration of NDMA precursors in the wastewater effluent and the overall dose of chlorine applied. Much of the NDMA formation occurred in chlorine contact basins or in storage basins where water that contained chloramines was held after disinfection. When landscape or crop irrigation is practiced with ammonia-containing wastewater effluent, NDMA production can be controlled by use of lower chlorine doses or by application of alternative disinfectants.

  14. Preliminary SEM Observations on the Surface of Elastomeric Impression Materials after Immersion or Ozone Disinfection

    Science.gov (United States)

    Prombonas, Anthony; Yannikakis, Stavros; Karampotsos, Thanasis; Katsarou, Martha-Spyridoula; Drakoulis, Nikolaos

    2016-01-01

    Introduction Surface integrity of dental elastomeric impression materials that are subjected to disinfection is of major importance for the quality of the final prosthetic restorations. Aim The aim of this qualitative Scanning Electronic Microscopy (SEM) study was to reveal the effects of immersion or ozone disinfection on the surface of four dental elastomeric impression materials. Materials and Methods Four dental elastomeric impression material brands were used (two vinyl polysiloxane silicones, one polyether, and one vinyl polyether silicone). Total of 32 specimens were fabricated, eight from each impression material. Specimens were immersion (0.525% sodium hypochlorite solution or 0.3% benzalkonium chloride solution) or ozone disinfected or served as controls and examined with SEM. Results Surface degradation was observed on several speci-mens disinfected with 0.525% sodium hypochlorite solution. Similar wavy-wrinkling surface structures were observed in almost all specimens, when treated either with 0.3% benzalkonium chloride solution or ozone. Conclusion The SEM images obtained from this study revealed that both immersion disinfectants and ozone show similar impression material surface alterations. Ozone seems to be non-inferior as compared to immersion disinfectants, but superior as to environmental protection. PMID:28208993

  15. The effect of chlorine and combined chlorine/UV treatment on coliphages in drinking water disinfection.

    Science.gov (United States)

    Zyara, Alyaa M; Torvinen, Eila; Veijalainen, Anna-Maria; Heinonen-Tanski, Helvi

    2016-08-01

    Chlorine disinfection is a globally used method to ensure the safety of drinking water. However, it has not always been successful against viruses and, therefore, it is important to find new methods to disinfect water. Seventeen different coliphages were isolated from the treated municipal wastewater. These coliphages and MS2 were treated with different dosages of chlorine in drinking water, and a combined chlorine/ultraviolet irradiation treatment for the chlorine-resistant coliphages. Chlorine disinfection with 0.3-0.5 mg/L total chlorine (free Cl-dosage 0.12-0.21 mg/L) for 10 min achieved 2.5-5.7 Log10-reductions for 11 sensitive coliphages. The six most resistant coliphages showed no reduction with these chlorine concentrations. MS2 was intermediate in chlorine resistance, and thus it is not a good indicator for viruses in chlorine disinfection. In the combined treatment total chlorine of 0.05-0.25 mg/L (free Cl-dosage 0.02-0.08 mg/L) and ultraviolet irradiation (14-22 mWs/cm(2)) were more effective than chlorine alone, and 3-5 Log10-reductions were achieved for the chlorine-resistant strains. The chlorination efficiency could be increased by higher dosages and longer contact times, but this could increase the formation of disinfection by-products. Therefore, the combination treatment is a recommended disinfection method.

  16. Effect of Disinfectants on Preventing the Cross-Contamination of Pathogens in Fresh Produce Washing Water

    Science.gov (United States)

    Banach, Jennifer L.; Sampers, Imca; Van Haute, Sam; van der Fels-Klerx, H.J. (Ine)

    2015-01-01

    The potential cross-contamination of pathogens between clean and contaminated produce in the washing tank is highly dependent on the water quality. Process wash water disinfectants are applied to maintain the water quality during processing. The review examines the efficacy of process wash water disinfectants during produce processing with the aim to prevent cross-contamination of pathogens. Process wash water disinfection requires short contact times so microorganisms are rapidly inactivated. Free chlorine, chlorine dioxide, ozone, and peracetic acid were considered suitable disinfectants. A disinfectant’s reactivity with the organic matter will determine the disinfectant residual, which is of paramount importance for microbial inactivation and should be monitored in situ. Furthermore, the chemical and worker safety, and the legislative framework will determine the suitability of a disinfection technique. Current research often focuses on produce decontamination and to a lesser extent on preventing cross-contamination. Further research on a sanitizer’s efficacy in the washing water is recommended at the laboratory scale, in particular with experimental designs reflecting industrial conditions. Validation on the industrial scale is warranted to better understand the overall effects of a sanitizer. PMID:26213953

  17. Chemical disinfection of combined sewer overflow waters using performic acid or peracetic acids.

    Science.gov (United States)

    Chhetri, Ravi Kumar; Thornberg, Dines; Berner, Jesper; Gramstad, Robin; Öjstedt, Ulrik; Sharma, Anitha Kumari; Andersen, Henrik Rasmus

    2014-08-15

    We investigated the possibility of applying performic acid (PFA) and peracetic acid (PAA) for disinfection of combined sewer overflow (CSO) in existing CSO management infrastructures. The disinfection power of PFA and PAA towards Escherichia coli (E. coli) and Enterococcus was studied in batch-scale and pre-field experiments. In the batch-scale experiment, 2.5 mg L(-1) PAA removed approximately 4 log unit of E. coli and Enterococcus from CSO with a 360 min contact time. The removal of E. coli and Enterococcus from CSO was always around or above 3 log units using 2-4 mg L(-1) PFA; with a 20 min contact time in both batch-scale and pre-field experiments. There was no toxicological effect measured by Vibrio fischeri when CSO was disinfected with PFA; a slight toxic effect was observed on CSO disinfected with PAA. When the design for PFA based disinfection was applied to CSO collected from an authentic event, the disinfection efficiencies were confirmed and degradation rates were slightly higher than predicted in simulated CSO. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Alternative disinfection technology for water purification systems; Josui shori ni okeru enso daitai shodoku gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    Aizawa, T. [The Institute of Public Health, Tokyo (Japan)

    1998-09-10

    This paper describes chlorination substituting disinfection technologies used in water purification systems. Chloramine treatment is regarded as effective in reducing trihalomethane (THM). Chlorine is injected in the initial stage in the form of free chlorine to disinfect pathogenic microorganisms in a short time, which is then added with ammonia to convert it into chloramine for further utilization. Chlorine dioxide has not been used in Japan, but introduced in Europe and America to treat THM. Ozone has the strongest oxidizing power, and is used for disinfection, virus inactivation, decomposition of THM precursors, and removal of fungus odor. The ozone treatment will produce aldehyde if an organic matter is present, but aldehyde can be removed by treatment using organismic activated carbon. Ultraviolet ray treatment has an advantage of being difficult of producing byproducts. This system was experimentally compared with free chlorine treatment on disinfection effect, mutagenicity, suppression of producing THM byproducts, and odor removal. In order to assure reliability of microorganismic and chemical safety in tap water supply systems, assurance by considering the entire system is important, not only by operating the disinfection units, but also combining such physical water purifying technologies as coagulation, sedimentation, filtration, and membrane treatment. The use of chlorine substituting disinfectants is also a part of the conception. 6 refs., 8 figs., 5 tabs.

  19. Effect of Disinfectants on Preventing the Cross-Contamination of Pathogens in Fresh Produce Washing Water

    Directory of Open Access Journals (Sweden)

    Jennifer L. Banach

    2015-07-01

    Full Text Available The potential cross-contamination of pathogens between clean and contaminated produce in the washing tank is highly dependent on the water quality. Process wash water disinfectants are applied to maintain the water quality during processing. The review examines the efficacy of process wash water disinfectants during produce processing with the aim to prevent cross-contamination of pathogens. Process wash water disinfection requires short contact times so microorganisms are rapidly inactivated. Free chlorine, chlorine dioxide, ozone, and peracetic acid were considered suitable disinfectants. A disinfectant’s reactivity with the organic matter will determine the disinfectant residual, which is of paramount importance for microbial inactivation and should be monitored in situ. Furthermore, the chemical and worker safety, and the legislative framework will determine the suitability of a disinfection technique. Current research often focuses on produce decontamination and to a lesser extent on preventing cross-contamination. Further research on a sanitizer’s efficacy in the washing water is recommended at the laboratory scale, in particular with experimental designs reflecting industrial conditions. Validation on the industrial scale is warranted to better understand the overall effects of a sanitizer.

  20. Effect of Gamma Radiation sterilization versus Disinfection on Removable Partial Dentures (Microbiological study)

    International Nuclear Information System (INIS)

    Mohammed, M.A.

    2011-01-01

    The aim of the study was to compare between the effectiveness of disinfection, using commercially available Fittydent super cleansing tablets versus sterilization, using gamma radiation on candidal growth in maxillary removable partial dentures. Methods: Fourteen partially edentulous subjects were selected according to specific criteria and divided equally and randomly into two groups; Group I: disinfection group and Group II: sterilization group. Conventional maxillary removable partial dentures were constructed for all subjects. The swab technique was used to collect the samples one month after denture delivery, immediately after disinfection/sterilization, and then one week, two weeks, three weeks, four weeks, and five weeks after disinfection/sterilization respectively. Bacteriological candidal colony count was performed using a manual contact colony counter. Results: Both methods (disinfection and sterilization) led to a noticeable decrease in the candidal count. However this decrease was highly and markedly evident in Group II as compared to Group I. Infact, no candidal growth was recorded for group II immediately after strerilization and was maintained for two more weeks. Statistical analysis revealed highly significant differences between the two groups. Conclusions: Both methods were effective in decreasing the number of Candida albicans adhering to the denture. However, sterilization using Gamma radiation had a more superior immediate, as well as, long term efficiency as compared to disinfection using Fittydent super cleansing tablets.