scholarly journals Sensitivity of Vermamoeba (Hartmannella) vermiformis cysts to conventional disinfectants and protease

2014 ◽  
Vol 13 (2) ◽  
pp. 302-310 ◽  
Author(s):  
Emilie Fouque ◽  
Yann Héchard ◽  
Philippe Hartemann ◽  
Philippe Humeau ◽  
Marie-Cécile Trouilhé
Keyword(s):  
Legionella Pneumophila ◽  
Pathogenic Bacteria ◽  
Hot Water ◽  
Water Networks ◽  
Important Health ◽  
Hartmannella Vermiformis ◽  
Important Health Issue ◽  
Few Data ◽  
First Time

Vermamoeba vermiformis is a free-living amoeba (FLA) widely distributed in the environment, known to colonize hot water networks and to be the reservoir of pathogenic bacteria such as Legionella pneumophila. FLA are partly resistant to biocides, especially in their cyst form. The control of V. vermiformis in hot water networks represents an important health issue, but there are very few data on their resistance to disinfection treatments. The sensitivity of cysts of two strains of V. vermiformis to three disinfectants frequently used in hot water networks (chlorine, heat shock, peracetic acid (PAA) mixed with hydrogen peroxide (H2O2)) was investigated. In vitro, several concentrations of biocides, temperatures and exposure times according to the French regulation were tested. Cysts were fully inactivated by the following conditions: 15 mg/L of chlorine for 10 min; 60 °C for 30 min; and 0.5 g/L equivalent H2O2 of PAA mixed with H2O2 for 30 min. For the first time, the strong efficacy of subtilisin (0.625 U/mL for 24 h), a protease, to inactivate the V. vermiformis cysts has been demonstrated. It suggests that novel approaches may be efficient for disinfection processes. Finally, V. vermifomis cysts were sensitive to all the tested treatments and appeared to be more sensitive than Acanthamoeba cysts.

scholarly journals Detection of Protozoan Hosts for Legionella pneumophila in Engineered Water Systems by Using a Biofilm Batch Test

2010 ◽  
Vol 76 (21) ◽  
pp. 7144-7153 ◽  
Author(s):  
Rinske M. Valster ◽  
Bart A. Wullings ◽  
Dick van der Kooij
Keyword(s):  
Legionella Pneumophila ◽  
Biofilm Formation ◽  
18S Rrna Gene ◽  
Rrna Gene ◽  
Batch Test ◽  
Free Living ◽  
Water Types ◽  
Operational Taxonomic Units ◽  
Hartmannella Vermiformis

ABSTRACT Legionella pneumophila proliferates in aquatic habitats within free-living protozoa, 17 species of which have been identified as hosts by using in vitro experiments. The present study aimed at identifying protozoan hosts for L. pneumophila by using a biofilm batch test (BBT). Samples (600 ml) collected from 21 engineered freshwater systems, with added polyethylene cylinders to promote biofilm formation, were inoculated with L. pneumophila and subsequently incubated at 37°C for 20 days. Growth of L. pneumophila was observed in 16 of 18 water types when the host protozoan Hartmannella vermiformis was added. Twelve of the tested water types supported growth of L. pneumophila or indigenous Legionella anisa without added H. vermiformis. In 12 of 19 BBT flasks H. vermiformis was indicated as a host, based on the ratio between maximum concentrations of L. pneumophila and H. vermiformis, determined with quantitative PCR (Q-PCR), and the composition of clone libraries of partial 18S rRNA gene fragments. Analyses of 609 eukaryotic clones from the BBTs revealed that 68 operational taxonomic units (OTUs) showed the highest similarity to free-living protozoa. Forty percent of the sequences clustering with protozoa showed ≥99.5% similarity to H. vermiformis. None of the other protozoa serving as hosts in in vitro studies were detected in the BBTs. In several tests with growth of L. pneumophila, the protozoa Diphylleia rotans, Echinamoeba thermarum, and Neoparamoeba sp. were identified as candidate hosts. In vitro studies are needed to confirm their role as hosts for L. pneumophila. Unidentified protozoa were implicated as hosts for uncultured Legionella spp. grown in BBT flasks at 15°C.

scholarly journals Age- and gender-dependent association of SLC11A1 polymorphisms with tuberculosis susceptibility

2021 ◽  
Author(s):  
Yuhe Wang ◽  
Zhongtao Wang ◽  
Xue He ◽  
Li Wang ◽  
Mei Bai ◽  
...  
Keyword(s):  
Unconditional Logistic Regression ◽  
Age And Gender ◽  
Genotype Frequencies ◽  
Important Health ◽  
And Gender ◽  
Important Health Issue ◽  
Regression Adjustment ◽  
Stratified Analysis ◽  
First Time ◽  
The Relationship

Abstract Background: Tuberculosis (TB) is an important health issue in our world. It is reported that various factors may effect on its pathogenesis. In this current study, we aimed to investigate the association between SLC11A1 polymorphism and the risk of TB among 510 TB patients and 508 healthy controls.Methods: Agena MassARRAY platform was conducted for genotyping. Odds ratios (ORs) and 95% confidence intervals (CIs) were analyzed through unconditional logistic regression adjustment confound factors, such as age and gender.Results: The results suggested that the allele and genotype frequencies of polymorphisms in SLC11A1 were not observed associated with TB risk. Subsequently, stratified analysis by age and gender confirmed that rs7608307 “A/A” and “C/T-T/T” genotypes were related with increased TB risk in age ≤ 41 group (p = 0.021) and males (p = 0.013), respectively. Besides, rs13062 “A/A” genotype was reduced TB risk in age > 41 group (p = 0.043). In addition, we observed that the “C/C” genotype of rs4674301 was noteworthy correlated with increased TB risk in females (p = 0.043). Conclusion: Our results demonstrated the relationship between SLC11A1 polymorphism and TB risk and confirmed for the first time that the correlation was restricted to age and gender in northwest Chinese population.

scholarly journals Heterologous Expression of the Pathogen-Specific LIC11711 Gene in the Saprophyte L. biflexa Increases Bacterial Binding to Laminin and Plasminogen

Pathogens ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 599
Author(s):  
Leandro Toshio Kochi ◽  
Luis Guilherme Virgílio Fernandes ◽  
Ana Lucia Tabet Oller Nascimento
Keyword(s):  
Molecular Biology ◽  
Heterologous Expression ◽  
Pathogenic Bacteria ◽  
Bacterial Pathogenesis ◽  
Bacterial Virulence ◽  
Febrile Disease ◽  
Bacterial Binding ◽  
Etiological Agents ◽  
First Time

Leptospirosis is a febrile disease and the etiological agents are pathogenic bacteria of the genus Leptospira. The leptospiral virulence mechanisms are not fully understood and the application of genetic tools is still limited, despite advances in molecular biology techniques. The leptospiral recombinant protein LIC11711 has shown interaction with several host components, indicating a potential function in virulence. This study describes a system for heterologous expression of the L. interrogans gene lic11711 using the saprophyte L. biflexa serovar Patoc as a surrogate, aiming to investigate its possible activity in bacterial virulence. Heterologous expression of LIC11711 was performed using the pMaOri vector under regulation of the lipL32 promoter. The protein was found mainly on the leptospiral outer surface, confirming its location. The lipL32 promoter enhanced the expression of LIC11711 in L. biflexa compared to the pathogenic strain, indicating that this strategy may be used to overexpress low-copy proteins. The presence of LIC11711 enhanced the capacity of L. biflexa to adhere to laminin (Lam) and plasminogen (Plg)/plasmin (Pla) in vitro, suggesting the involvement of this protein in bacterial pathogenesis. We show for the first time that the expression of LIC11711 protein of L. interrogans confers a virulence-associated phenotype on L. biflexa, pointing out possible mechanisms used by pathogenic leptospires.

scholarly journals Trans Fat Free by 2023—A Building Block of the COVID-19 Response

2021 ◽  
Vol 8 ◽  
Author(s):  
Simone Bösch ◽  
Lucinda Westerman ◽  
Nina Renshaw ◽  
Igor Pravst
Keyword(s):  
Trans Fatty Acids ◽  
Cardiovascular Health ◽  
Trans Fat ◽  
The Public ◽  
Important Health ◽  
Policy Measures ◽  
Important Health Issue ◽  
First Time ◽  
Global Food ◽  
Global Food Supply

COVID-19 has brought to center stage the most important health issue of our era, largely ignored by policymakers and the public to date: non-communicable diseases (NCDs), the cause of 71% of deaths per year worldwide. People living with NCDs, and particularly those living with cardiovascular disease (CVD), are at higher risk of severe symptoms and death from COVID-19. As a result, the urgent need for policy measures to protect cardiovascular health is more apparent than ever. One example of “low-hanging fruit” in the prevention of CVD is the elimination of industrially-produced trans fatty acids (iTFA). Their removal from the global food supply could prevent up to 17 million deaths by 2040 and would be the first time an NCD risk factor has been eliminated.

scholarly journals Viability PCR, a Culture-Independent Method for Rapid and Selective Quantification of Viable Legionella pneumophila Cells in Environmental Water Samples

2009 ◽  
Vol 75 (11) ◽  
pp. 3502-3512 ◽  
Author(s):  
Pilar Delgado-Viscogliosi ◽  
Lydie Solignac ◽  
Jean-Marie Delattre
Keyword(s):  
Legionella Pneumophila ◽  
Water Samples ◽  
Environmental Water ◽  
Hot Water ◽  
Culture Methods ◽  
Culture Techniques ◽  
Viability Assay ◽  
Viable Cells ◽  
Wide Range

ABSTRACT PCR-based methods have been developed to rapidly screen for Legionella pneumophila in water as an alternative to time-consuming culture techniques. However, these methods fail to discriminate between live and dead bacteria. Here, we report a viability assay (viability PCR [v-PCR]) for L. pneumophila that combines ethidium monoazide bromide with quantitative real-time PCR (qPCR). The ability of v-PCR to differentiate viable from nonviable L. pneumophila cells was confirmed with permeabilizing agents, toluene, or isopropanol. v-PCR suppressed more than 99.9% of the L. pneumophila PCR signal in nonviable cultures and was able to discriminate viable cells in mixed samples. A wide range of physiological states, from culturable to dead cells, was observed with 64 domestic hot-water samples after simultaneous quantification of L. pneumophila cells by v-PCR, conventional qPCR, and culture methods. v-PCR counts were equal to or higher than those obtained by culture and lower than or equal to conventional qPCR counts. v-PCR was used to successfully monitor in vitro the disinfection efficacy of heating to 70°C and glutaraldehyde and chlorine curative treatments. The v-PCR method appears to be a promising and rapid technique for enumerating L. pneumophila bacteria in water and, in comparison with conventional qPCR techniques used to monitor Legionella, has the advantage of selectively amplifying only viable cells.

scholarly journals Presence of Legionella spp. in Hot Water Networks of Different Italian Residential Buildings: A Three-Year Survey

2017 ◽  
Author(s):  
Michele Totaro ◽  
Paola Valentini ◽  
Anna Laura Costa ◽  
Lorenzo Frendo ◽  
Alessia Cappello ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Water Samples ◽  
Cold Water ◽  
Residential Buildings ◽  
Hot Water ◽  
Water Production ◽  
Water Networks ◽  
Legionella Species ◽  
Solar Thermal System ◽  
And Control

Although the European reports highlight an increase in community-acquired Legionnaires’ disease cases, the risk of Legionella spp. in private houses is underestimated. In Pisa (Italy) we performed a three-year survey on Legionella presence in 121 buildings with an independent hot water production (IB); 64 buildings with a central hot water production (CB); and 35 buildings with a solar thermal system for hot water production (TB). From all the 220 buildings Legionella spp. was researched in two hot water samples collected either at the recirculation point or at on the first floor and on the last floor, while the potable water quality was analyzed in three cold water samples collected at the inlet from the aqueduct network, at the exit from the autoclave, and at the most remove remote? tap. Legionella pneumophila sg1, Legionella pneumophila sg2-16 and not-pneumophila Legionella species were detected in 26% of the hot water networks, mostly in CB and TB. In these buildings we detected correlations between the presence of Legionella and the total chlorine concentration decrease or/and the increase of the temperature. Cold water resulted free from microbiological hazards, with the exception of Serratia liquefaciens and Enterobacter cloacae isolated at the exit from two different autoclaves. We observed an increase in total microbial counts at 22 and 37°C between the samples collected at the most remote taps compared to the ones collected at the inlet from the aqueduct. The study highlights a condition of potential risk for susceptible categories of population and supports the need for measures of risk assessment and control.

scholarly journals Pathogenicity of bacteria isolated from 'Hua Moa' plantain with bunch abortion symptoms inoculated into other clones of plantain and banana.

1969 ◽  
Vol 91 (1-2) ◽  
pp. 19-30
Author(s):  
Judith Rengifo ◽  
Mildred Zapata ◽  
Manuel Díaz ◽  
Rafael Inglés
Keyword(s):  
Puerto Rico ◽  
Pathogenic Bacteria ◽  
Soft Rot ◽  
Field Studies ◽  
Bacterial Diseases ◽  
Burkholderia Gladioli ◽  
Agar Media ◽  
The Caribbean ◽  
First Time

Plantain production (Musa spp.) in Central and South America and the Caribbean is affected by bacterial diseases. In Puerto Rico, production of the plantain 'Hua Moa' is affected by a condition known as bunch abortion or 'choke neck'. This condition in some cases is accompanied by soft rot symptoms and therefore could be related to phytopathogenic bacteria. The purpose of this study was to identify the bacteria related to the soft rot tissues on plants affected with the bunch abortion symptoms and determine their virulence in other clones of plantain and banana. Bacterial colonies were isolated from pseudostems of Hua Moa at three locations in Puerto Rico, using semi-selective and nutritive agar media. The pathogenicity was determined by using potato and plantain pseudostem discs in humid chambers under in vitro conditions. Pathogenic bacteria were identified by using the BIOLOG® system. Under greenhouse conditions, the virulence of Burkholderia gladioli, Pseudomonas spinosa, Erwinia chrysanthemi and Pseudomonas aeruginosa was confirmed on plantain (Maricongo, FIAH-121, Enano Común, and Hua Moa) and banana (Grand Nain) using a scale from 1 to 9. All clones evaluated under greenhouse conditions were susceptible to E. chrysanthemi, potential causal agent of soft rot in Hua Moa plantain once the bunch abortion appears. Burkholderia gladioli is reported for the first time affecting plantain and banana.This bacterium was more virulent in Hua Moa and Grand Nain clones with severity of 7 and 5, respectively, than in Maricongo, severity 3. Pseudomonas spinosa and P. aeruginosa produced less damage with severity less than 4, than E. chrysanthemi and B. gladioli with severity greater than 4. This research was conducted under in vitro and greenhouse conditions and demonstrates that the most important bacteria causing soft rot in plants with the choke neck condition are E. chrysanthemi and B. gladioli. It is recommended to conduct field studies using plants up to the reproductive stage to determine whether these bacteria are also related as causal agents of the choke neck.

scholarly journals Evaluation of Legionella pneumophila Decrease in Hot Water Network of Four Hospital Buildings after Installation of Electron Time Flow Taps

Water ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 210 ◽  
Author(s):  
Michele Totaro ◽  
Tommaso Mariotti ◽  
Costanza Bisordi ◽  
Erica De Vita ◽  
Paola Valentini ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Cold Water ◽  
Control Measure ◽  
Critical Issue ◽  
Hot Water ◽  
Low Flow ◽  
Water Networks ◽  
Water Network ◽  
Time Flow ◽  
Chemical Disinfection

Legionella spp. control is a critical issue in hospital with old water networks. Chemical disinfection methods are applied as a control measure over prolonged time periods, but Legionella may be resistant to chemical agents in pipeworks with low flow and frequent water stagnation. We evaluated Legionella spp. colonization in the hot water network of Italian hospitals after the installation of time flow taps (TFTs). In the period between 2017 and 2019, TFTs were installed in four hospital water networks. They were programmed in order to obtain a hot water flow of 192 L/day from each TFTs. A continuous chlorination system (chlorine dioxide) and a cold water pre-filtration device were applied in all the buildings. Before and after TFT installation, Legionella spp. was investigated at scheduled times. Before TFT installation, Legionella pneumophila was detected in all the hospitals with counts ranging from 2 × 102 to 1.4 × 105 CFU/L. After TFT installation, a loss in Legionella pneumophila culturability was always achieved in the period between 24 h and 15 days. Total chlorine concentration (Cl2) was detected in the range between 0.23 and 0.36 mg/L while temperature values were from 44.8 to 53.2 °C. TFTs together with chemical disinfection represent a method which improve water quality and disinfectant efficacy, reducing Legionella colonization in dead-end sections.

scholarly journals DNA Microarray for Rapid Detection and Identification of Food and Water Borne Bacteria: From Dry to Wet Lab

2017 ◽  
Vol 11 (1) ◽  
pp. 330-338 ◽  
Author(s):  
Reza Ranjbar ◽  
Payam Behzadi ◽  
Ali Najafi ◽  
Raheleh Roudi
Keyword(s):  
Dna Microarray ◽  
Legionella Pneumophila ◽  
Rapid Detection ◽  
Pathogenic Bacteria ◽  
Microarray Chip ◽  
Dna Labeling ◽  
Detection And Identification ◽  
Oligo Microarray ◽  
Wet Lab

Background:A rapid, accurate, flexible and reliable diagnostic method may significantly decrease the costs of diagnosis and treatment. Designing an appropriate microarray chip reduces noises and probable biases in the final result.Objective:The aim of this study was to design and construct a DNA Microarray Chip for a rapid detection and identification of 10 important bacterial agents.Method:In the present survey, 10 unique genomic regions relating to 10 pathogenic bacterial agents includingEscherichia coli (E.coli), Shigella boydii, Sh.dysenteriae, Sh.flexneri, Sh.sonnei, Salmonella typhi, S.typhimurium, Brucella sp., Legionella pneumophila,andVibrio cholerawere selected for designing specific long oligo microarray probes. For this reason, the in-silico operations including utilization of the NCBI RefSeq database, Servers of PanSeq and Gview, AlleleID 7.7 and Oligo Analyzer 3.1 was done. On the other hand, thein-vitropart of the study comprised stages of robotic microarray chip probe spotting, bacterial DNAs extraction and DNA labeling, hybridization and microarray chip scanning. In wet lab section, different tools and apparatus such as Nexterion® Slide E, Qarrayminispotter, NimbleGen kit, TrayMixTMS4, and Innoscan 710 were used.Results:A DNA microarray chip including 10 long oligo microarray probes was designed and constructed for detection and identification of 10 pathogenic bacteria.Conclusion:The DNA microarray chip was capable to identify all 10 bacterial agents tested simultaneously. The presence of a professional bioinformatician as a probe designer is needed to design appropriate multifunctional microarray probes to increase the accuracy of the outcomes.

Somatic Embryogenesis and In vitro Plant Regeneration in Vigna trilobata (L.) Verd. - A Potential Pasture Legume

1970 ◽  
Vol 19 (1) ◽  
pp. 89-99
Author(s):  
K. Choudhary ◽  
M. Singh ◽  
M. S. Rathore ◽  
N. S. Shekhawat
Keyword(s):  
Somatic Embryogenesis ◽  
Growth Regulators ◽  
Somatic Embryos ◽  
Basal Medium ◽  
Long Term Study ◽  
Continuous Application ◽  
First Time ◽  
Pasture Legume

This long term study demonstrates for the first time that it is possible to propagate embryogenic Vigna trilobata and to subsequently initiate the differentiation of embryos into complete plantlets. Initiation of callus was possible on 2,4-D. Somatic embryos differentiated on modified MS basal nutrient medium with 1.0 mg/l  of 2,4-D and 0.5 mg/l  of Kn. Sustained cell division resulted in globular and heart shape stages of somatic embryos. Transfer of embryos on to a fresh modified MS basal medium with 0.5 mg/l of Kn and 0.5 mg/l of GA3 helped them to attain maturation and germination. However, the propagation of cells, as well as the differentiation of embryos, were inhibited by a continuous application of these growth regulators. For this reason, a long period on medium lacking these growth regulators was necessary before the differentiation of embryos occurred again. The consequences for improving the propagation of embryogenic cultures in Vigna species are discussed. Key words: Pasture  legume, Vigna trilobata, Globular, Heart shape, somatic embryogenesis D.O.I. 10.3329/ptcb.v19i1.4990 Plant Tissue Cult. & Biotech. 19(1): 89-99, 2009 (June)

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