Evaluation and use of a low nutrient medium and reduced incubation temperature to study bacterial contamination in the water supply of dental units

1994 ◽  
Vol 40 (2) ◽  
pp. 127-131 ◽  
Author(s):  
H. N. Williams ◽  
H. Quinby ◽  
E. Romberg
Keyword(s):  
Water Supply ◽  
Nutrient Medium ◽  
Bacterial Contamination ◽  
Bacterial Population ◽  
Incubation Temperature ◽  
Stagnant Water ◽  
Bacterial Colony ◽  
Colony Forming Units ◽  
Peptone Medium ◽  
Incubation Temperatures

A low nutrient medium, dilute peptone, and reduced incubation temperatures (25 or 30 °C) were used to recover bacteria from dental unit water supply. Significantly greater numbers of bacterial colony-forming units were recovered on the dilute peptone medium than on the enriched media, blood agar or trypticase soy agar. Lower incubation temperatures yielded greater numbers of colony-forming units on all media. The bacterial population in dental unit water supply following stagnation in the supply lines and flushing of the lines was studied using dilute peptone incubated at 25 °C. No significant differences in the numbers of colony-forming units were found in stagnant water versus fresh water. Flushing the water lines for 10 min did not significantly reduce the numbers of colony-forming units.Key words: dental unit water, water contamination, bacterial contamination.

Sensitivity to hypoxia and microbial activity are instrumental in pericarp-imposed dormancy expression in sunflower (Helianthus annuus L.)

2019 ◽  
Vol 29 (2) ◽  
pp. 85-96 ◽  
Author(s):  
Constanza P. Dominguez ◽  
María V. Rodríguez ◽  
Diego Batlla ◽  
Inés E. García de Salamone ◽  
Anita I. Mantese ◽  
...  
Keyword(s):  
Microbial Activity ◽  
Incubation Temperature ◽  
Bacterial Load ◽  
Bacterial Colony ◽  
Aba Metabolism ◽  
Increased Sensitivity ◽  
Bacteria And Fungi ◽  
Incubation Temperatures ◽  
Aba Content

AbstractWe used two sunflower genotypes displaying pericarp-imposed dormancy at high incubation temperatures (i.e. 30°C) to investigate the role of the pericarp as a limitation to oxygen availability to the embryo (hypoxia), and its impact on embryo abscisic acid (ABA) content and sensitivity to ABA. Results showed that both genotypes displayed very different oxygen threshold values for inhibition of embryo germination when incubation was performed at 30°C. Expression of dormancy in one genotype was therefore related to exacerbated embryo sensitivity to hypoxia, whereas in the other genotype, the pericarp appeared to act as a more severe restraint to oxygen entry. Increased sensitivity to hypoxia was, in part, related to increased sensitivity to ABA, but not to alterations in ABA metabolism. The activity of pericarp-microbial communities (bacteria and fungi) at high temperatures was also assessed as a potential determinant of hypoxia to the embryo. Oxygen consumption in pericarps incubated at 30°C was attenuated with antibiotics, which concomitantly promoted achene germination. In agreement with the observed more severe oxygen deprivation to the embryo exerted by the pericarp, the bacterial load in the pericarp was significantly higher in the commercial hybrid than in the inbred line; however, the application of antibiotics strongly reduced the bacterial colony counts for each genotype. Different bacterial and fungal communities, assessed through their profiles of carbon-source utilization, were determined between genotypes and after treatment with antibiotics. This work highlights the relationship between enhancement of sensitivity to hypoxia with incubation temperature and seed dormancy expression, and suggests that microbial activity might be part of the mechanism through which hypoxia is imposed.

ВПЛИВ ДЖЕРЕЛ АЗОТНОГО ЖИВЛЕННЯ НА СИНТЕЗ КАРОТИНОЇДІВ ДЕЯКИМИ ШТАМАМИ БАЗИДІОМІЦЕТІВ

2014 ◽  
Vol 4 (01) ◽  
pp. 22
Author(s):  
A. K. Veligodska ◽  
O. V. Fedotov ◽  
A. S. Petreeva
Keyword(s):  
Culture Filtrate ◽  
Nutrient Medium ◽  
Culture Fluid ◽  
Carotenoid Content ◽  
Nitrogen Compounds ◽  
Total Carotenoid ◽  
Carotenoid Accumulation ◽  
Total Carotenoid Content ◽  
Peptone Medium ◽  
Acetone Extracts

<p>The influence of certain nitrogen compounds - components of glucose-peptone medium (GPM) on the accumulation of carotenoids by some strains was investigated by surface cultivating basidiomycetes. The total carotenoid content was set in acetone extracts of mycological material spectrophotometrically and calculated using the Vetshteyn formula.</p> <p>As the nitrogen-containing components used GPM with 9 compounds, such as peptone, DL-valine, L-asparagine, DL-serine, DL-tyrosine, L-proline, L-alanine, urea, NaNO<sub>3</sub>. The effect on the accumulation of specific compounds both in the mycelium and in the culture fluid of carotenoids by culturing certain strains of Basidiomycetes was identified.</p> <p>Adding to standard glucose-peptone medium peptone at 5 g/l causes an increase of carotenoid accumulation by strain <em>L. sulphureus</em> Ls-08, and in a concentration of 4 g/l by strains of <em>F. hepatica </em>Fh-18 and <em>F. fomentarius</em> Ff-1201.</p> <p>In order to increase the accumulation of carotenoids in the mycelium  we suggested to make a standard glucose-peptone medium with proline or valine for cultivating of <em>L. sulphureus</em> Ls- 08 strain; alanine for <em>F. fomentarius</em> Ff-1201 strain; proline, asparagine and serine - for strain Fh-18 of <em>F. hepatica</em>. The results can be implemented in further optimization of the composition of the nutrient medium for culturing strains of Basidiomycetes wich producing carotenoids.</p> <p><em>Keywords: nitrogen-containing substances, Basidiomycetes, mycelium</em><em>,</em><em> culture filtrate, carotenoids</em></p>

Phytotoxic Effect of Decaying Quackgrass (Agropyron repens) Residues

Weed Science ◽  
1979 ◽  
Vol 27 (6) ◽  
pp. 595-598 ◽  
Author(s):  
T. V. Toai ◽  
D. L. Linscott
Keyword(s):  
Incubation Temperature ◽  
Soil Surface ◽  
Water Soluble ◽  
Water Extracts ◽  
Phytotoxic Activity ◽  
Phytotoxic Effect ◽  
Effects Of Temperature ◽  
Incubation Temperatures ◽  
Toxin Formation ◽  
Agropyron Repens

We studied the effects of temperature (5, 10, 20, and 30 C) on the phytotoxic activity of decaying quackgrass [Agropyron repens (L.) Beauv.] leaves and rhizomes that were incubated in soils for 0, 1, 2, 4, and 6 weeks. Alfalfa (Medicago sativa L.) seeds were grown for 96 h in water, water extracts of control soils, and water extracts of soil with quackgrass rhizomes or leaves. Dried quackgrass rhizomes and leaves contained water-soluble toxins that inhibited alfalfa seedling development and growth. There was a strong interaction between incubation time and temperature on the development of additional toxins by decomposing quackgrass. High incubation temperature (30 C) accelerated toxin formation and ultimate decay. Intermediate temperature (20 C) delayed toxin formation and decay. Low incubation temperatures (5 C and 10 C) prevented formation of additional toxin. In all extracts of quackgrass and soil that had been incubated for 6 weeks, normal alfalfa seedling number equaled that in water. However, seedling growth varied with incubation temperatures.Treatment of quackgrass with glyphosate [N-(phosphonomethyl) glycine] in the greenhouse did not influence the toxicity of decaying quackgrass leaves. The highest toxic effect was noted after 1 week of decay on the soil surface.

scholarly journals Differences in susceptibility of marine bacterial communities to metal pyrithiones, their degradation compounds and organotin antifouling biocides

2019 ◽  
Vol 99 (5) ◽  
pp. 1033-1039
Author(s):  
Madoka Ohji ◽  
Hiroya Harino ◽  
William John Langston
Keyword(s):  
Life History ◽  
Degradation Product ◽  
Bacterial Communities ◽  
Degradation Products ◽  
High Susceptibility ◽  
Zinc Pyrithione ◽  
Bacterial Colony ◽  
Indigenous Bacteria ◽  
Antifouling Biocides ◽  
Colony Forming Units

AbstractThe susceptibility of marine bacterial communities to copper pyrithione (CuPT2), zinc pyrithione (ZnPT2) and their degradation product is described and toxicities of these relatively new antifouling biocides compared with those of their harmful organotin (OT) predecessors, tributyltin (TBT) and triphenyltin (TPT). These biocides were added to agar at concentrations of 0, 0.01, 0.1, 1 and 10 mg l−1and coastal seawater including indigenous bacteria added to each batch of agar solution. The number of bacterial colony forming units (CFU) was measured after 7 days culture. Relative CFU (as a percentage of control) was more than 80% at a concentration of 0.01 mg l−1of each compound, except for TBT. Relative CFU decreased as a function of dose of each biocide, although concentration-dependent changes in rate of CFU were relatively low during exposure to degradation products of CuPT2and ZnPT2, pyridineN-oxide (PO) and pyridine-2-sulphonic acid (PSA). Based on comparisons of EC50, TBT was the most bacterio-toxic of the tested compounds (0.2 mg l−1), marginally more so than CuPT2(0.3 mg l−1). Interestingly, EC50values of degradation products of CuPT2and ZnPT2, 2-mercaptopyridineN-oxide (HPT) and 2,2′-dithio-bispyridineN-oxide (PT2) were 0.8 and 0.5 mg l−1, respectively, lower than that of the parent chemical, ZnPT2(1.4 mg l−1). The EC50of PT2was also lower than that of TPT (0.7 mg l−1), implying higher toxicity. Given the overlapping toxicity ranges, these results suggest that marine bacterial communities experience comparably high susceptibility to metal PTs and OTs during their life history.

Temperature studies of iron-oxidizing autotrophs and acidophilic heterotrophs isolated from uranium mines

1993 ◽  
Vol 39 (4) ◽  
pp. 384-388 ◽  
Author(s):  
Deborah Berthelot ◽  
L. G. Leduc ◽  
G. D. Ferroni
Keyword(s):  
Water Samples ◽  
Mine Water ◽  
Thiobacillus Ferrooxidans ◽  
Incubation Temperature ◽  
Temperature Growth ◽  
Temperature Range ◽  
Uranium Mines ◽  
Iron Oxidizing Bacteria ◽  
Colony Forming Units ◽  
Growth Profiles

Iron-oxidizing autotrophs and acidophilic heterotrophs were quantified at an incubation temperature of 18 °C in several samples obtained from the bioleaching areas of two uranium mines in Ontario, Canada. All samples were mine-water samples with temperatures in the range 13–18 °C. Iron-oxidizing autotrophs ranged from 2683 ± 377 to 245 000 ± 20 205 colony-forming units∙mL−1 and were always numerically superior to acidophilic heterotrophs, which ranged from 40 ± 8 to 9650 ± 161 colony-forming units∙mL−1. For each sample, approximately 20 isolates of each nutritional group were examined for the ability to grow at temperatures of 4, 18, 21, and 37 °C, respectively; overall, 559 isolates of iron-oxidizing bacteria (predominantly Thiobacillus ferrooxidans) and 252 acidophilic heterotrophic isolates were examined and categorized as 'broader temperature range psychrotrophs,' 'narrower temperature range psychrotrophs,' 'intermediates,' or mesophiles. Although psychrotrophic representatives of both groups were abundant, no psychrophiles were recovered from any of the samples. For the iron oxidizers, the temperature growth profiles of the isolates were similar from sample to sample. For the acidophilic heterotrophs, the temperature growth profiles varied considerably among samples.Key words: psychrotrophs; Thiobacillus ferrooxidans; uranium mines.

scholarly journals Automated Counting of Bacterial Colony Forming Units on Agar Plates

PLoS ONE ◽  
2012 ◽  
Vol 7 (3) ◽  
pp. e33695 ◽  
Author(s):  
Silvio D. Brugger ◽  
Christian Baumberger ◽  
Marcel Jost ◽  
Werner Jenni ◽  
Urs Brugger ◽  
...  
Keyword(s):  
Bacterial Colony ◽  
Colony Forming Units

Thermal and water source effects upon the stability of enteroviruses in surface freshwaters

1989 ◽  
Vol 35 (4) ◽  
pp. 474-480 ◽  
Author(s):  
Christon J. Hurst ◽  
William H. Benton ◽  
Kim A. McClellan
Keyword(s):  
Bacterial Growth ◽  
Incubation Temperature ◽  
Water Source ◽  
Inactivation Rate ◽  
Human Enterovirus ◽  
Strongly Correlated ◽  
Artificial Lake ◽  
Viral Inactivation ◽  
Term Survival ◽  
Incubation Temperatures

The long-term survival of three human enterovirus serotypes, Coxsackievirus B3, echovirus 7, and poliovirus 1 was examined in samples of surface freshwater collected from five sites of physically different character. These were an artificial lake created by damming a creek, a small groundwater outlet pond, both a large- and a medium-sized river, and a small suburban creek. Survival was studied at temperatures of −20, 1, and 22 °C. The average amount of viral inactivation was 6.50–7.0 log10 units over 8 weeks at 22 °C, 4–5 log10 units over 12 weeks at 1 °C, and 0.4–0.8 log10 units over 12 weeks at −20 °C. The effect of incubation temperature upon viral inactivation rate was statistically significant (p < 0.00001). As determined by pairing tests, survival was also significantly related to both viral serotype and water source at each of the three incubation temperatures (p ≤ 0.05). Efforts were made to determine whether the rate of viral inactivation observed at the different incubation temperatures was related to characteristics inherent to the water that was collected from the different locations. The characteristics examined included physical and chemical parameters, indigenous bacterial counts, and the amount of bacterial growth that the waters would support (measured as the maximum number of generations which seeded bacteria could undergo after being placed into either pasteurized or sterile-filtered water samples). Analysis of viral inactivation rate versus these characteristics revealed three apparent effectors of viral persistence. These were (i) hardness and conductivity, both of which strongly correlated with one another; (ii) turbidity and suspended solids content, both of which strongly correlated with one another; and (iii) the number of generations of bacterial growth that a sample was capable of supporting, which also correlated with hardness and conductivity.Key words: virus, survival, inactivation rate, water.

Nest temperature´s influence on morphology of Dermochelys coriacea hatchlings incubated in hatcheries in Oaxaca, Mexico

2021 ◽  
Author(s):  
Jesús García-Grajales ◽  
Juan Francisco Meraz ◽  
José Luis Arcos García ◽  
Eustacio Ramírez Méndez
Keyword(s):  
Incubation Temperature ◽  
Carapace Width ◽  
Principal Component ◽  
Dermochelys Coriacea ◽  
Egg Mass ◽  
Natural Environments ◽  
Data Logger ◽  
Geometric Morphometric ◽  
Low Weight ◽  
Incubation Temperatures

The influence of nest incubation temperatures on the carapace shape and morphological traits of Dermochelys coriacea (Vandelli 1761) hatchlings incubated in two hatcheries of Oaxaca, Mexico was evaluated. This study was carried out from October 2016 through May 2017. On each beach, there are community groups consisting of volunteers without association with universities, that protect and relocate the nests to increase hatching success. In each translocated nest, a data logger was placed in the centre of the egg mass. Hatchlings were collected as they emerged from each nest. The carapaces of the hatchlings were photographed and subjected to geometric morphometric analysis; later, hatchlings were weighed and their bodies were measured. The mean temperature of 12 nests in each hatchery were recorded, with no significant differences between hatcheries. The principal component analysis (PCA) revealed an overlapping of the carapace shape under different duration of temperature. Temperature had a significant influence on hatchling morphology. Higher mean incubation temperatures produced hatchlings with low weight, smaller appendage; narrower carapace width and shorter flippers length. Lower mean incubation temperatures produced hatchlings that had greater weight, greater appendage width, wider carapace width and longer flipper length. Results indicate that the D. coriacea hatchlings incubated in hatcheries demonstrate morphology that varies in relation to nest incubation temperature in a similar way to hatchlings produced in natural environments.

Effectiveness of antimicrobial hospital curtains on reducing bacterial contamination—A multicenter study

2018 ◽  
Vol 40 (2) ◽  
pp. 164-170 ◽  
Author(s):  
Shik Luk ◽  
Viola Chi Ying Chow ◽  
Kelvin Chung Ho Yu ◽  
Enoch Know Hsu ◽  
Ngai Chong Tsang ◽  
...  
Keyword(s):  
Multicenter Study ◽  
Bacterial Contamination ◽  
Indirect Costs ◽  
Multidrug Resistant ◽  
Clinical Settings ◽  
Carbapenem Resistant ◽  
Colony Forming Units ◽  
Multidrug Resistant Organisms ◽  
Bed Days

AbstractObjectiveTo determine the efficacy of 2 types of antimicrobial privacy curtains in clinical settings and the costs involved in replacing standard curtains with antimicrobial curtains.DesignA prospective, open-labeled, multicenter study with a follow-up duration of 6 months.SettingThis study included 12 rooms of patients with multidrug-resistant organisms (MDROs) (668 patient bed days) and 10 cubicles (8,839 patient bed days) in the medical, surgical, neurosurgical, orthopedics, and rehabilitation units of 10 hospitals.MethodCulture samples were collected from curtain surfaces twice a week for 2 weeks, followed by weekly intervals.ResultsWith a median hanging time of 173 days, antimicrobial curtain B (quaternary ammonium chlorides [QAC] plus polyorganosiloxane) was highly effective in reducing the bioburden (colony-forming units/100 cm2, 1 vs 57; P < .001) compared with the standard curtain. The percentages of MDRO contamination were also significantly lower on antimicrobial curtain B than the standard curtain: methicillin-resistant Staphylococcus aureus, 0.5% vs 24% (P < .001); carbapenem-resistant Acinetobacter spp, 0.2% vs 22.1% (P < .001); multidrug-resistant Acinetobacter spp, 0% vs 13.2% (P < .001). Notably, the median time to first contamination by MDROs was 27.6 times longer for antimicrobial curtain B than for the standard curtain (138 days vs 5 days; P = .001).ConclusionsAntimicrobial curtain B (QAC plus polyorganosiloxane) but not antimicrobial curtain A (built-in silver) effectively reduced the microbial burden and MDRO contamination compared with the standard curtain, even after extended use in an active clinical setting. The antimicrobial curtain provided an opportunity to avert indirect costs related to curtain changing and laundering in addition to improving patient safety.

scholarly journals The impact of bacterial contamination of the ejaculate and extender on the quality of swine semen doses

2017 ◽  
Vol 38 (5) ◽  
pp. 3095 ◽  
Author(s):  
Ana Maria Groehs Goldberg ◽  
Marisa Cardoso ◽  
Mari Lourdes Bernardi ◽  
Ivo Wentz ◽  
Fernando Pandolfo Bortolozzo
Keyword(s):  
Bacterial Contamination ◽  
Sperm Morphology ◽  
No Reduction ◽  
Degree Of Contamination ◽  
Colony Forming Units ◽  
Semen Processing ◽  
Semen Extender ◽  
Contamination Levels ◽  
The Impact

The aim of this study was to verify the influence of the degree of bacterial contamination of boar ejaculate and semen extender on the quality of semen doses. The experiment was conducted in four boar studs, from which raw semen and two semen doses from each ejaculate were collected to evaluate the number of colony-forming units (CFU), pH, sperm morphology and motility. Extender samples were also evaluated for CFU. Ejaculates that had higher levels of contamination ( > 220 CFU mL-1) resulted in semen doses with a greater degree of bacterial contamination but with no reduction in motility or alteration in pH. When the semen doses were classified according to the degree of contamination of the extender, a decrease in motility was observed after 108 and 168 h of storage (P < 0.05) in the group whose extender had ? 14,000 CFU mL-1 versus the group whose extender had ? 330 CFU mL-1. The pH remained stable during 168 h of storage in semen doses with extender that had lower contamination levels, but decreased from 7.2 to 6.0 between 24 and 168 h of storage (P < 0.05) in the group with extender that had higher levels of contamination. A higher number of abnormal acrosomes (P < 0.05) were observed after 168 h of storage in the semen doses whose extender was highly contaminated. The production of semen doses with low bacterial contamination and high sperm cell viability will only be possible with a strict hygienic control in semen processing, primarily with respect to the extender, combined with minimal contamination during collection.

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