scholarly journals Diversity and Seasonal Impact ofAcanthamoebaSpecies in a Subtropical Rivershed

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Po-Min Kao ◽  
Ming-Yuan Chou ◽  
Chi-Wei Tao ◽  
Wen-Chien Huang ◽  
Bing-Mu Hsu ◽  
...  
Keyword(s):  
Water Samples ◽  
Enrichment Culture ◽  
Human Health Risk ◽  
Culture Method ◽  
Acanthamoeba Keratitis ◽  
Four Seasons ◽  
Seasonal Impact ◽  
Subtropical Monsoon Climate ◽  
The Relationship ◽  
Risk Potential

This study evaluated the presence ofAcanthamoebaspecies in the Puzih River watershed, which features typical subtropical monsoon climate and is located just above the Tropic of Cancer in Taiwan. The relationship between the seasonal and geographical distributions ofAcanthamoebaspecies in this rivershed was also investigated.Acanthamoebaspecies were detected in water samples using the amoebal enrichment culture method and confirmed by PCR. A total of 136 water samples were included in this study, 16 (11.7%) of which containedAcanthamoebaspecies. Samples with the highest percentage ofAcanthamoeba(32.4%) were obtained during the summer season, mainly from upstream areas. The identified species in the four seasons includedAcanthamoeba palestinensis(T2),Acanthamoebasp. IS2/T4 (T4),Acanthamoeba lenticulata(T5),Acanthamoeba hatchetti(T11),Acanthamoeba healyi(T12), andAcanthamoeba jacobsi(T15). The most frequently identifiedAcanthamoebagenotype was T4 (68.7%).Acanthamoebagenotype T4 is responsible forAcanthamoeba keratitisand should be considered for associated human health risk potential in the rivershed.

Comparison of Cell Culture and a Poliovirus Gene Probe Assay for the Detection of Enteroviruses in Environmental Water Samples

1993 ◽  
Vol 27 (3-4) ◽  
pp. 311-314 ◽  
Author(s):  
Aaron B. Margolin ◽  
Charles P. Gerba ◽  
Kenneth J. Richardson ◽  
Jaime E. Naranjo
Keyword(s):  
Cell Culture ◽  
Activated Sludge ◽  
Water Samples ◽  
Cdna Probe ◽  
Culture Method ◽  
Tidal River ◽  
Nucleic Acid Hybridization ◽  
Treated Wastewater ◽  
Gene Probe ◽  
Naturally Occurring

Nucleic acid hybridization provides a rapid non-cell culture method for the detection of enteric viruses in water. The purpose of this work was to compare the detection of naturally occurring enteroviruses by cell culture with their detection by a poliovirus gene probe in various types of water samples. Samples of activated sludge effluent, tertiary treated wastewater (activated sludge, filtration and passage through reverse osmosis), ground water, surface water and tidal river water were processed through 1 MDS Virozorb filters to concentrate any naturally occurring virus. Viruses were eluted from the filters with pH 9.5 beef extract and reduced in volume by flocculation to 20-30 ml. These concentrates were then assayed in the BGM cell line by the cytopathogenic effects (CPE) method and by a poliovirus cDNA probe (base pairs 115-7440) labeled with 32P. A total of 233 samples were assayed in this manner. In slightly more than 93% of the samples gene probe and cell culture yielded the same results. Of these samples 36 were positive by gene probe and 28 by cell culture assay. Positive samples for gene probe were confirmed by treatment with NaOH or RNAse and then reprobed. Samples demonstrating CPE upon primary passage were confirmed positive by subsequent passage of cell lysate on a new monolayer of BGM cells. Ten samples were positive by gene probe and negative by cell culture, and 4 samples were negative by gene probe and positive by cell culture.

scholarly journals Comparing the Yield of Staphylococcus aureus Recovery with Static versus Agitated Broth Incubation

2018 ◽  
Vol 2018 ◽  
pp. 1-3
Author(s):  
Carol E. Muenks ◽  
Patrick G. Hogan ◽  
Carey-Ann D. Burnham ◽  
Stephanie A. Fritz
Keyword(s):  
Staphylococcus Aureus ◽  
Enrichment Culture ◽  
Culture Method ◽  
Ambient Air ◽  
Built Environments ◽  
Culture Methods ◽  
Semiquantitative Assessment ◽  
Direct Plating ◽  
Static Conditions ◽  
Broth Enrichment

Given the lack of standardization of methodologies for microbial recovery from built environments, we sought to compare the yield of Staphylococcus aureus with a broth enrichment method when incubated in agitated versus static conditions. Five unique strains of S. aureus at five different concentrations were cultured to compare direct plating, agitated broth enrichment, and static broth enrichment culture methods. All samples were incubated at 35° in ambient air. The lowest concentration recovered across three replicates and five strains did not differ between culture methods (Fisher’s exact test, p=0.50); notably, recovery of S. aureus was equivalent between static and agitated broth incubation. When broth enrichment was used (both static and agitated), the burden of S. aureus growth was higher (by semiquantitative assessment of 4-quadrant streaking) compared to the direct plating culture method. Optimizing strategies for microbial recovery is essential, particularly in areas of lower biomass, given the paucity of research concerning microbial communities of built environments. The results of this study, in conjunction with other experiments investigating microbiomes of built environments, can help inform protocols for standardizing culturing methods within built environments.

Effects of pH and alkalinity on sulfur-denitrification in a biological granular filter

1996 ◽  
Vol 34 (1-2) ◽  
pp. 355-362 ◽  
Author(s):  
Hiroaki Furumai ◽  
Hideki Tagui ◽  
Kenji Fujita
Keyword(s):  
Enrichment Culture ◽  
Nitrite Reduction ◽  
The Other ◽  
Nitrite Accumulation ◽  
Ph Dependency ◽  
Effects Of Ph ◽  
Rapid Removal ◽  
Nitrate And Nitrite ◽  
The Relationship ◽  
Biological Filters

Two laboratory-scale biological filters were operated to investigate the effects of alkalinity and pH on removal of nitrate and nitrite in sulfur denitrification filter processes. The concentration of sodium bicarbonate in the feed media was changed from 120 to 240 mg/l during about 3 months in a filter (Run A). The other filter was initially fed with 300 mg/l and then with 240 mg/l (Run B). The performance of the filter was monitored by measuring pH, nitrate, nitrite, sulfate, alkalinity, and thiosulfate. Nitrate concentration in effluent rapidly decreased to lower levels within several days for both filters after inoculation of enrichment culture of sulfur denitrifiers. However there was a large difference in removal of nitrite. When rapid removal of nitrate took place, nitrite accumulation was observed and remained while the bicarbonate concentration was 120 and 150 mg/l. On the other hand the nitrite accumulation disappeared when more bicarbonate (240 and 300 mg/l) was supplied. The experimental results indicated that the nitrite accumulation was closely related to pH condition and alkalinity level in the filter. The stable data of effluent water quality for 5 cases were collected and the relationship discussed between nitrite concentration and pH in effluents. The relationship indicated a strong pH dependency on nitrite accumulation below pH of 7.4. The pH condition around 7 is not so inhibitory to biological activity. Therefore, the pH within the biofilm would be low enough to suppress the nitrite reduction by sulfur denitrifiers, while the pH in effluent was not in the inhibitory range. It was recommended to keep the pH higher than 7.4 to prevent nitrite accumulation in the sulfur denitrification filter.

scholarly journals Performance of Legiolert Test vs. ISO 11731 to Confirm Legionella pneumophila Contamination in Potable Water Samples

Pathogens ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 690 ◽  
Author(s):  
Maria Scaturro ◽  
Matteo Buffoni ◽  
Antonietta Girolamo ◽  
Sandra Cristino ◽  
Luna Girolamini ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Legionella Pneumophila ◽  
Water Samples ◽  
Gold Standard ◽  
Liquid Culture ◽  
Potable Water ◽  
Culture Method ◽  
Alternative Methods ◽  
Significant Difference

Detection and enumeration of Legionella in water samples is of great importance for risk assessment analysis. The plate culture method is the gold standard, but has received several well-known criticisms, which have induced researchers to develop alternative methods. The purpose of this study was to compare Legionella counts obtained by the analysis of potable water samples through the plate culture method and through the IDEXX liquid culture Legiolert method. Legionella plate culture, according to ISO 11731:1998, was performed using 1 L of water. Legiolert was performed using both the 10 mL and 100 mL Legiolert protocols. Overall, 123 potable water samples were analyzed. Thirty-seven (30%) of them, positive for L. pneumophila, serogroups 1 or 2–14 by plate culture, were used for comparison with the Legiolert results. The Legiolert 10 mL test detected 34 positive samples (27.6%) and the Legiolert 100 mL test detected 37 positive samples, 27.6% and 30% respectively, out of the total samples analyzed. No significant difference was found between either the Legiolert 10 mL and Legiolert 100 mL vs. the plate culture (p = 0.9 and p = 0.3, respectively) or between the Legiolert 10 mL and Legiolert 100 mL tests (p = 0.83). This study confirms the reliability of the IDEXX Legiolert test for Legionella pneumophila detection and enumeration, as already shown in similar studies. Like the plate culture method, the Legiolert assay is also suitable for obtaining isolates for typing purposes, relevant for epidemiological investigations.

scholarly journals The relationship between environmental sources and the susceptibility of Acanthamoeba keratitis in the United Kingdom

PLoS ONE ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. e0229681 ◽  
Author(s):  
Nicole A. Carnt ◽  
Dinesh Subedi ◽  
Sophie Connor ◽  
Simon Kilvington
Keyword(s):  
United Kingdom ◽  
Acanthamoeba Keratitis ◽  
The United Kingdom ◽  
The Relationship

scholarly journals Multicenter Diagnostic Accuracy Evaluation of the Luminex Aries Real-Time PCR Assay for Group B Streptococcus Detection in Lim Broth-Enriched Samples

2018 ◽  
Vol 56 (8) ◽  
Author(s):  
D. R. Hernandez ◽  
D. M. Wolk ◽  
K. L. Walker ◽  
S. Young ◽  
R. Dunn ◽  
...  
Keyword(s):  
Clinical Performance ◽  
Enrichment Culture ◽  
Culture Method ◽  
Nucleic Acid Amplification ◽  
Accuracy Evaluation ◽  
Culture Methods ◽  
Assay Sensitivity ◽  
Content Type ◽  
Group B ◽  
Positive Agreement

ABSTRACT The vertical transmission of group B Streptococcus (GBS) strains causing neonatal sepsis is one of the leading reasons for neonatal mortality worldwide. The gold standard for GBS detection is enriched culture with or without the aid of chromogenic agars. Given the high risk for morbidity and mortality in this population, high assay sensitivity is required to prevent the personal and economic costs of GBS disease. Nucleic acid amplification tests (NAATs) allow for objective determination of GBS colonization with a sensitivity and a specificity higher than those of traditional culture methods. In this study, we determined the analytical and clinical performance of the Aries GBS assay compared to those of the enrichment culture method, biochemical identification, and the NAATs used at the study sites. Remnant Lim broth samples were used to perform the Aries assay and reference testing. Upon first testing using enriched culture as the reference standard, the Aries GBS assay identified GBS with a 96.1% sensitivity (95% confidence interval [CI], 91.2 to 98.7%) and a 91.4% specificity (95% CI, 88.8 to 93.6%). The test performed with 100% positive agreement (95% CI, 83.2 to 100%) compared to the results of the BD Max GBS assay and 98.0% positive agreement (95% CI, 89.2 to 99.9%) compared to the results of the Cepheid Xpert GBS LB test. Repeatability and reproducibility were maintained in intra- and interlaboratory testing, regardless of the instrument, module, or user who performed the test. The Aries GBS assay can be set up in less than 5 min and produces results in 2 h. The easy setup, with minimal hands-on time, and high assay sensitivity and specificity make this a useful testing option for GBS screening in prepartum women.

Temperature effect on compression property of multiaxial warp-knitted composites

2019 ◽  
Vol 32 (4) ◽  
pp. 469-479
Author(s):  
Xiaori Yang ◽  
Cong Wang ◽  
Xiaoping Gao ◽  
Lvtao Zhu ◽  
Yonggui Li
Keyword(s):  
Failure Strain ◽  
Turbine Blades ◽  
Effect Of Temperature ◽  
Wind Turbine Blades ◽  
Electron Microscopic ◽  
Compression Property ◽  
Compression Performance ◽  
Four Seasons ◽  
Scanning Electron Microscopic ◽  
The Relationship

The wind turbine blades are exposed to various environments all the year round, especially temperature variations during the four seasons. To study the influences of temperatures on the mechanical properties of composite materials, the compression property in the 0°, 45°, and 90° directions of the multiaxial (triaxial and quadaxial) glass fiber warp-knitted composites at −30°C, 0°C, 20°C, and 40°C was analyzed, respectively. The stress–strain curves, strength, modulus, failure strain, and the relationship between strength and temperature were obtained. The results indicated that the compression performance decreased with the increase of temperature, and the effect of temperature on quadaxial composite was more significant than that of the triaxial composite. In addition, the failure mechanisms were also analyzed according to the fracture modes and scanning electron microscopic morphologies of composites.

Analysis of the Temporal-Spatial Characteristics of Cloud Parameters and the Relationship with the Precipitation over Qilian Mountains Area in Northwest China

2020 ◽  
Author(s):  
Wu Zhang ◽  
Ying Wang ◽  
Qingyun Zhao ◽  
Chen Pu ◽  
Yan Chen
Keyword(s):  
Water Resources ◽  
Water Resource ◽  
Northwest China ◽  
Cloud Water ◽  
Qilian Mountains ◽  
Physical Parameters ◽  
Cloud Parameters ◽  
Four Seasons ◽  
Cloud Parameter ◽  
The Relationship

<p>Qilian mountains, located in the arid and semi-arid region of Northwest China, has more amount of natural precipitation than that on both north and south sides, with unique geographical environment and abundant water vapor supply. It is a very important water resource for the surrounding areas. To deeper understand the features of cloud over the areas is significant for the utilization of cloud water resources and sustainable development in this region. In this article, based on MOD08-M3 data, grid ground precipitation data and FY-2 series satellite cloud parameter inversion products, the spatial and temporal features of cloud macro/micro physical parameters, such as Cloud Amount（CA）, Cloud Water Path（CWP）, Cloud Top Temperature（CTT）, Cloud Top Pressure（CTP）, Cloud Optical Depth（COD） and Cloud Particle Effective Radius (CPER) over Qilian Mountains area were analyzed, as well as the relationship between the precipitation and cloud parameters. The results are as follows:</p><ul><li>(1) The regional average values of CA, CWP, CTP, COD and CPER in Qilian Mountains area are 55.50 %, 148.95 g/m², -21.13 ℃, 456.56 hPa, 12.64 and 21.04 μm, respectively. From 2006 to 2015, CA, CWP, COD and CPER decreased by 2.3 %, 21 g/m², 0.68 and 0.51 μm, respectively. CTT and CTP increased by 1.9 ℃ and 65.2 hPa, respectively. Cloud water resources over the area are abundant.</li> <li>(2) There is the richest cloud water resource over the main area of Qilian Mountains, and the cloud parameter condition in Wushaoling area is the best for precipitation. The high value areas of CA in four seasons are distributed in Xining and surroundings, main and south part of mountain range, and Lenghu area, respectively. The high value areas of CWP in four seasons are located in the northeast, north-middle the main part of mountain area and the eastern side of Subei, respectively. The high value areas of COD are located in the east of Subei in winter and in the southeast of the study area in other seasons. The high value areas of CPER in spring are located in the region except Hexi Corridor. In other seasons they are located between Lenghu and Subei, Subei and Tuole, and in the northeast of range, respectively.</li> <li>(3) The monthly precipitation is positively correlated with CA , CWP, COD, but negatively correlated with CTT and CTP. The relationship between CPERs and precipitation is positive in January, April, July, November and December, but negative in other months. CA and CPERs are most correlated with precipitation in May and September, respectively. while the correlation between other cloud parameters and precipitation are the highest in January.</li> <li>(4) When the values of COD and CPER are too small or too large, the actual precipitation will be limited.</li> </ul><p><strong>Key words: </strong>Cloud physical parameters; Precipitation; Water resource; Qilian Mountains</p>

scholarly journals Microbial source tracking and spatial analysis of E. coli contaminated private well waters in southeastern Ontario

2013 ◽  
Vol 12 (2) ◽  
pp. 348-357 ◽  
Author(s):  
Julia Krolik ◽  
Gerald Evans ◽  
Paul Belanger ◽  
Allison Maier ◽  
Geoffrey Hall ◽  
...  
Keyword(s):  
Rural Communities ◽  
Water Samples ◽  
Human Health Risk ◽  
Primary Source ◽  
Developed Countries ◽  
Microbial Source Tracking ◽  
Source Tracking ◽  
Future Research ◽  
Well Water ◽  
Specific Marker

Private water supplies, which are the primary source of drinking water for rural communities in developed countries, are at risk of becoming fecally contaminated. It is important to identify the source of contamination in order to better understand and address this human health risk. Microbial source tracking methods using human, bovine and general Bacteroidales markers were performed on 716 well water samples from southeastern Ontario, which had previously tested positive for Escherichia coli. The results were then geospatially analyzed in order to elucidate contamination patterns. Markers for human feces were found in nearly half (49%) of all samples tested, and a statistically significant spatial cluster was observed. A quarter of the samples tested positive for only general Bacteroidales markers (25.7%) and relatively few bovine specific marker positives (12.6%) were found. These findings are fundamental to the understanding of pathogen dynamics and risk in the context of drinking well water and will inform future research regarding host-specific pathogens in private well water samples.

scholarly journals Limitations of Using Propidium Monoazide with qPCR to Discriminate between Live and Dead Legionella in Biofilm Samples

2014 ◽  
Vol 7 ◽  
pp. MBI.S17723 ◽  
Author(s):  
Michael J. Taylor ◽  
Richard H. Bentham ◽  
Kirstin E. Ross
Keyword(s):  
Public Health ◽  
Real Time ◽  
Real Time Pcr ◽  
Culture Method ◽  
Propidium Monoazide ◽  
Factors Affecting ◽  
Conventional Culture ◽  
Target Dna ◽  
The Relationship ◽  
Conventional Culture Method

Accurately quantifying Legionella for regulatory purposes to protect public health is essential. Real-time PCR (qPCR) has been proposed as a better method for detecting and enumerating Legionella in samples than conventional culture method. However, since qPCR amplifies any target DNA in the sample, the technique's inability to discriminate between live and dead cells means that counts are generally significantly overestimated. Propidium monoazide (PMA) has been used successfully in qPCR to aid live/dead discrimination. We tested PMA use as a method to count only live Legionella cells in samples collected from a modified chemostat that generates environmentally comparable samples. Counts from PMA-treated samples that were pretreated with either heat or three types of disinfectants (to kill the cells) were highly variable, with the only consistent trend being the relationship between biofilm mass and numbers of Legionella cells. Two possibilities explain this result: 1. PMA treatment worked and the subsequent muted response of Legionella to disinfection treatment is a factor of biofilm/microbiological effects; although this does not account for the relationship between the amount of biofilm sampled and the viable Legionella count as determined by PMA-qPCR; or 2. PMA treatment did not work, and any measured decrease or increase in detectable Legionella is because of other factors affecting the method. This is the most likely explanation for our results, suggesting that higher concentrations of PMA might be needed to compensate for the presence of other compounds in an environmental sample or that lower amounts of biofilm need to be sampled. As PMA becomes increasingly toxic at higher concentrations and is very expensive, augmenting the method to include higher PMA concentrations is both counterproductive and cost prohibitive. Conversely, if smaller volumes of biofilm are used, the reproducibility of the method is reduced. Our results suggest that using PMA is not an appropriate method for discriminating between live and dead cells to enumerate Legionella for regulatory purposes.

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