Effects of simulated solar disinfection of water on infectivity of Salmonella typhimurium

Smith, Rebecca J.; Kehoe, S.C.; McGuigan, Kevin G.; Barer, Michael R.

doi:10.1046/j.1472-765x.2000.00815.x

Cited by 69 publications

(47 citation statements)

References 20 publications

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“…Some authors reported the existence of viable but non-culturable (VBNC) bacteria in environmental samples (Kjelleberg et al, 1993;Knight et al, 1990;Pommepuy et al, 1996 andRoszak andColwell, 1987), which would not be enriched in a pre-cultivation step and thus may escape detection. Medema et al (1992), Caro et al (1999) and Smith et al (2000) reported a loss of pathogenicity associated with non-culturability of S. typhimurium when subjected to seawater stress, solar and ultraviolet-C irradiation. Although the cultivation step excludes the detection of VBNC Salmonella, such bacteria most probably pose no significant threat to humans because of the minimum infectious dose of Salmonella (10 5 / 10 9 for S. typhi/ S. typhimurium respectively) required to initiate a disease (Le Minor, 1981).…”

Section: Discussionmentioning

confidence: 99%

Optimisation of the PCR-invA primers for the detection of Salmonella in drinking and surface waters following a pre-cultivation step

Moganedi¹,

Goyvaerts²,

Venter³

et al. 2009

WSA

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A polymerase chain reaction (PCR)-based method for the detection of Salmonella species in water samples was optimised and evaluated for speed, specificity and sensitivity. Optimisation of Mg 2+ and primer concentrations and cycling parameters increased the sensitivity and limit of detection of PCR to 2.6 x 10 4 cfu/mℓ. A 6h non-selective pre-enrichment step further increased the limit of detection to 26 cfu/mℓ. Out of 14 different Salmonella strains tested, only two, Salmonella arizonae and Salmonella pullorum, did not give positive amplification results with primers homologous to a conserved region of the invA gene. When environmental and drinking waters were assessed, a non-selective pre-enrichment step was included to increase the detection efficiency of PCR. The PCR method demonstrated specificity in the presence of other competing micro-organisms as confirmed by the conventional culture method. No false positives or negatives were observed when household and environmental water samples were tested by invA-PCR analysis parallel to the culture method.

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Section: Discussionmentioning

confidence: 99%

Optimisation of the PCR-invA primers for the detection of Salmonella in drinking and surface waters following a pre-cultivation step

Moganedi¹,

Goyvaerts²,

Venter³

et al. 2009

WSA

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“…Solar disinfection (SODIS) involves storing contaminated drinking water in transparent containers that are placed in direct sunlight for periods of up to 8 h before consumption (3,16). This technique is highly effective against a broad range of pathogens (4,8,9,15,17). Previous studies report reductions in the incidence of diarrhea in children who used SODIS compared with children who did not (3, 4).…”

mentioning

confidence: 99%

“…This technique is highly effective against a broad range of pathogens (4,8,9,15,17). Previous studies report reductions in the incidence of diarrhea in children who used SODIS compared with children who did not (3,4).…”

mentioning

confidence: 99%

Effect of Batch-Process Solar Disinfection on Survival of Cryptosporidium parvum Oocysts in Drinking Water

Méndez-Hermida

Castro‐Hermida

Ares-Mazás

et al. 2005

Appl Environ Microbiol

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The results of batch-process solar disinfection (SODIS) of Cryptosporidium parvum oocysts in water are reported. Oocyst suspensions were exposed to simulated sunlight (830 W m ؊2 ) at 40°C. Viability assays (4,6-diamidino-2-phenylindole [DAPI]/propidium iodide and excystation) and infectivity tests (Swiss CD-1 suckling mice) were performed. SODIS exposures of 6 and 12 h reduced oocyst infectivity from 100% to 7.5% (standard deviation ‫؍‬ 2.3) and 0% (standard deviation ‫؍‬ 0.0), respectively. Solar disinfection (SODIS) involves storing contaminated drinking water in transparent containers that are placed in direct sunlight for periods of up to 8 h before consumption (3,16). This technique is highly effective against a broad range of pathogens (4,8,9,15,17). Previous studies report reductions in the incidence of diarrhea in children who used SODIS compared with children who did not (3, 4). The biocidal effect of sunlight is due to optical and thermal processes, and a strong synergistic effect occurs at temperatures exceeding 45°C (11,12). The aim of our research was to test if inactivation of Cryptosporidium parvum oocysts could be achieved by batchprocess SODIS. Viability reduction after SODIS was tested by fluorogenic dyes and excystation techniques, while oocyst infectivity was determined in neonatal Swiss CD-1 mice. Ten coccidian-free litters of mice weighing from 2.5 to 3.0 g were used for this study. Each exposure time was assayed in duplicate with from 13 to 22 mice.C. parvum was collected from naturally infected calves by rectal sampling. Storage, concentration, and purification from feces were performed as reported previously (10). Oocysts were classified as of the bovine genotype (1). Suspensions of 10 7 purified oocysts were resuspended in 10 ml of distilled water in transparent polystyrene six-well microtiter containers with lids (IWAKI 3810-006; Tokyo, Japan) and irradiated with 830 W of simulated sunlight m Ϫ2 at a temperature of 40°C, using the system described previously (9). Viability and infectivity assays were performed after SODIS durations of 0, 6, and 12 h. Unexposed control samples were wrapped in aluminum and kept at room temperature or at 40°C in the water bath beside the test samples, as required. The viability and infectivity assays have been described by Freire et al. (5) and Lorenzo et al. (10). The data obtained in the studies were analyzed by a test of comparison of proportions and analysis of variance (ANOVA) (Sigmastat for Windows, version 1.0, 1994). Differences in infection intensities were compared by pair-wise multiple-comparison procedures (Student-Newman-Keuls method) and one-way ANOVA.Results are displayed in Table 1. Viability assays. Assays with the C. parvum isolate used for the experiments shows 93% of the oocysts excysted and 98% of oocysts were potentially viable by the fluorogenic dye test. The viability test using fluorogenic dyes showed that the oocysts stored at 40°C in the absence of optical irradiation remained relatively constant over 12 h at 89% (standard dev...

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“…However, 16 h of natural sunlight required for 1.3 log reduction of Bacillus subtilis endospores [10,15,28,39,[47][48][49][50].…”

Section: Inactivation Of Microorganismsmentioning

confidence: 99%

Drinking Water Disinfection by Solar Radiation

Teksoy¹,

Eleren²

2017

eer

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A primary concern of developing countries throughout the world is that of obtaining safe drinking water. Waterborne diseases are still common in developing countries since drinking water sources are contaminated and the conventional rural water treatment plants are often inefficient to produce safe drinking water. This situation in developing countries is a major problem in terms of preventing public health. It is estimated that diarrhea accounted for 99% of the 69 million deaths among children before the age of five. Inadequate operation and maintenance after installations caused by a lack of trained operators, by a treacherous supply of chemicals and spare parts, and by financial problems lead to produce unhealthy drinking water. Since major urban water supplies are also not always capable of maintaining a regular supply of qualitatively good water, the distributed water is often considered unsafe for direct consumption. Treatment of water at the household level (etc. boiling) or purchasing of mineral water for consumption is more real than an exception in urban areas of developing countries. Recently, another small-scale approach using the lethal effect of sunlight has gained importance to sanitary contaminated water. Solar disinfection (SODIS) is one of the simplest methods for providing acceptable quality drinking water and consists of filling transparent containers (plastic bags, plastic bottles or glass bottles) with water and exposing the containers to sunlight for approximately 6 hours. Because of the low cost and easy usage, solar disinfection is commonly used in developing countries in Asia, Africa and South America. The aim of this literature review is to give information about solar disinfection mechanism, to compare the efficiency of solar disinfection on different microorganisms based on the past studies, and to discuss the several applications of solar disinfection in the world.

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Effects of simulated solar disinfection of water on infectivity of Salmonella typhimurium

Cited by 69 publications

References 20 publications

Optimisation of the PCR-invA primers for the detection of Salmonella in drinking and surface waters following a pre-cultivation step

Optimisation of the PCR-invA primers for the detection of Salmonella in drinking and surface waters following a pre-cultivation step

Effect of Batch-Process Solar Disinfection on Survival of Cryptosporidium parvum Oocysts in Drinking Water

Drinking Water Disinfection by Solar Radiation

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