scholarly journals Distribution of Bacillus thuringiensis subsp. israelensis in Soil of a Swiss Wetland Reserve after 22 Years of Mosquito Control

2011 ◽  
Vol 77 (11) ◽  
pp. 3663-3668 ◽  
Author(s):  
Valeria Guidi ◽  
Nicola Patocchi ◽  
Peter Lüthy ◽  
Mauro Tonolla
Keyword(s):  
Spatial Distribution ◽  
Bacillus Thuringiensis ◽  
Confidence Interval ◽  
Quantitative Pcr ◽  
Mosquito Control ◽  
Soil Samples ◽  
Sampling Point ◽  
Content Type ◽  
Large Numbers ◽  
Continuous Accumulation

ABSTRACTRecurrent treatments withBacillus thuringiensissubsp.israelensisare required to control the floodwater mosquitoAedes vexansthat breeds in large numbers in the wetlands of the Bolle di Magadino Reserve in Canton Ticino, Switzerland. Interventions have been carried out since 1988. In the present study, the spatial distribution of restingB. thuringiensissubsp.israelensisspores in the soil was measured. TheB. thuringiensissubsp.israelensisconcentration was determined in soil samples collected along six transects covering different elevations within the periodically flooded zones. A total of 258 samples were processed and analyzed by quantitative PCR that targeted an identical fragment of 159 bp for theB. thuringiensissubsp.israelensis cry4Aaandcry4Bagenes.B. thuringiensissubsp.israelensisspores were found to persist in soils of the wetland reserve at concentrations of up to 6.8 log per gram of soil. Continuous accumulation due to regular treatments could be excluded, as the decrease in spores amounted to 95.8% (95% confidence interval, 93.9 to 97.7%). The distribution of spores was correlated to the number ofB. thuringiensissubsp.israelensistreatments, the elevation of the sampling point, and the duration of the flooding periods. The number ofB. thuringiensissubsp.israelensistreatments was the major factor influencing the distribution of spores in the different topographic zones (P< 0.0001). These findings indicated thatB. thuringiensissubsp.israelensisspores are rather immobile after their introduction into the environment.

scholarly journals Detection of Coxiella burnetii in Complex Matrices by Using Multiplex Quantitative PCR during a Major Q Fever Outbreak in The Netherlands

2011 ◽  
Vol 77 (18) ◽  
pp. 6516-6523 ◽  
Author(s):  
A. de Bruin ◽  
A. de Groot ◽  
L. de Heer ◽  
J. Bok ◽  
P. R. Wielinga ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
The Netherlands ◽  
Quantitative Pcr ◽  
Coxiella Burnetii ◽  
Internal Control ◽  
Q Fever ◽  
Qpcr Assay ◽  
Environmental Matrices ◽  
Content Type ◽  
Control Target

ABSTRACTQ fever, caused byCoxiella burnetii, is a zoonosis with a worldwide distribution. A large rural area in the southeast of the Netherlands was heavily affected by Q fever between 2007 and 2009. This initiated the development of a robust and internally controlled multiplex quantitative PCR (qPCR) assay for the detection ofC. burnetiiDNA in veterinary and environmental matrices on suspected Q fever-affected farms. The qPCR detects threeC. burnetiitargets (icd,com1, and IS1111) and oneBacillus thuringiensisinternal control target (cry1b).Bacillus thuringiensisspores were added to samples to control both DNA extraction and PCR amplification. The performance of the qPCR assay was investigated and showed a high efficiency; a limit of detection of 13.0, 10.6, and 10.4 copies per reaction for the targetsicd,com1, and IS1111, respectively; and no cross-reactivity with the nontarget organisms tested. Screening forC. burnetiiDNA on 29 suspected Q fever-affected farms during the Q fever epidemic in 2008 showed that swabs from dust-accumulating surfaces contained higher levels ofC. burnetiiDNA than vaginal swabs from goats or sheep. PCR inhibition by coextracted substances was observed in some environmental samples, and 10- or 100-fold dilutions of samples were sufficient to obtain interpretable signals for both theC. burnetiitargets and the internal control. The inclusion of an internal control target and threeC. burnetiitargets in one multiplex qPCR assay showed that complex veterinary and environmental matrices can be screened reliably for the presence ofC. burnetiiDNA during an outbreak.

scholarly journals Functional Bacillus thuringiensis Cyt1Aa Is Necessary To Synergize Lysinibacillus sphaericus Binary Toxin (Bin) against Bin-Resistant and -Refractory Mosquito Species

2020 ◽  
Vol 86 (7) ◽  
Author(s):  
Nathaly Alexandre Nascimento ◽  
Mary Carmen Torres-Quintero ◽  
Samira López Molina ◽  
Sabino Pacheco ◽  
Tatiany Patrícia Romão ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Insect Resistance ◽  
Mosquito Control ◽  
Specific Binding ◽  
Mosquito Species ◽  
Binary Toxin ◽  
Binding Interaction ◽  
Data Set ◽  
Lysinibacillus Sphaericus ◽  
Content Type

ABSTRACT The binary (Bin) toxin from Lysinibacillus sphaericus is effective to mosquito larvae, but its utilization is threatened by the development of insect resistance. Bin toxin is composed of the BinB subunit required for binding to midgut receptors and the BinA subunit that causes toxicity after cell internalization, mediated by BinB. Culex quinquefasciatus resistance to this toxin is caused by mutations that prevent expression of Bin toxin receptors in the midgut. Previously, it was shown that the Cyt1Aa toxin from Bacillus thuringiensis subsp. israelensis restores Bin toxicity to Bin-resistant C. quinquefasciatus and to Aedes aegypti larvae, which are naturally devoid of functional Bin receptors. Our goal was to elucidate the mechanism involved in Cyt1Aa synergism with Bin in such larvae. In vivo assays showed that the mixture of Bin toxin, or its BinA subunit, with Cyt1Aa was effective to kill resistant larvae. However, no specific binding interaction between Cyt1Aa and the Bin toxin, or its subunits, was observed. The synergy between Cyt1Aa and Bin toxins is dependent on functional Cyt1Aa, as demonstrated by using the nontoxic Cyt1AaV122E mutant toxin affected in oligomerization and membrane insertion, which was unable to synergize Bin toxicity in resistant larvae. The synergism correlated with the internalization of Bin or BinA into anterior and medium midgut epithelial cells, which occurred only in larvae treated with wild-type Cyt1Aa toxin. This toxin is able to overcome failures in the binding step involving BinB receptor by allowing the internalization of Bin toxin, or its BinA subunit, into the midgut cells. IMPORTANCE One promising management strategy for mosquito control is the utilization of a mixture of L. sphaericus and B. thuringiensis subsp. israelensis insecticidal toxins. From this set, Bin and Cyt1Aa toxins synergize and display toxicity to resistant C. quinquefasciatus and to A. aegypti larvae, whose midgut cells lack Bin toxin receptors. Our data set provides evidence that functional Cyt1Aa is essential for internalization of Bin or its BinA subunit into such cells, but binding interaction between Bin and Cyt1Aa is not observed. Thus, this mechanism contrasts with that for the synergy between Cyt1Aa and the B. thuringiensis subsp. israelensis Cry toxins, where active Cyt1Aa is not necessary but a specific binding between Cry and Cyt1Aa is required. Our study established the initial molecular basis of the synergy between Bin and Cyt1Aa, and these findings enlarge our knowledge of their mode of action, which could help to develop improved strategies to cope with insect resistance.

scholarly journals Fate of Bacillus thuringiensis subsp. israelensis in the Field: Evidence for Spore Recycling and Differential Persistence of Toxins in Leaf Litter

2012 ◽  
Vol 78 (23) ◽  
pp. 8362-8367 ◽  
Author(s):  
Guillaume Tetreau ◽  
Mattia Alessi ◽  
Sylvie Veyrenc ◽  
Sophie Périgon ◽  
Jean-Philippe David ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Leaf Litter ◽  
Mosquito Control ◽  
Crystal Form ◽  
High Concentration ◽  
Content Type ◽  
Breeding Sites ◽  
Commercial Mixture ◽  
Field Evidence ◽  
Larval Toxicity

ABSTRACTBacillus thuringiensissubsp.israelensisis a bioinsecticide increasingly used worldwide for mosquito control. Despite its apparent low level of persistence in the field due to the rapid loss of its insecticidal activity, an increasing number of studies suggested that the recycling ofB. thuringiensissubsp.israelensiscan occur under specific, unknown conditions. Decaying leaf litters sampled in mosquito breeding sites in the French Rhône-Alpes region several months after a treatment were shown to exhibit a high level of larval toxicity and contained large amounts of spores. In the present article, we show that the high concentration of toxins found in these litters is consistent with spore recycling in the field, which gave rise to the production of new crystal toxins. Furthermore, in these toxic leaf litter samples, Cry4Aa and Cry4Ba toxins became the major toxins instead of Cyt1Aa in the commercial mixture. In a microcosm experiment performed in the laboratory, we also demonstrated that the toxins, when added in their crystal form to nontoxic leaf litter, exhibited patterns of differential persistence consistent with the proportions of toxins observed in the field-collected toxic leaf litter samples (Cry4 > Cry11 > Cyt). These results give strong evidence thatB. thuringiensissubsp.israelensisrecycled in specific breeding sites containing leaf litters, and one would be justified in asking whether mosquitoes can become resistant when exposed to field-persistentB. thuringiensissubsp.israelensisfor several generations.

scholarly journals Multitarget Quantitative PCR Improves Detection and Predicts Cultivability of the Pathogen Burkholderia pseudomallei

2017 ◽  
Vol 83 (8) ◽  
Author(s):  
Andre Göhler ◽  
Trinh Thanh Trung ◽  
Verena Hopf ◽  
Christian Kohler ◽  
Jörg Hartleib ◽  
...  
Keyword(s):  
Quantitative Pcr ◽  
Burkholderia Pseudomallei ◽  
Detection Rate ◽  
Soil Samples ◽  
Single Type ◽  
Comparative Genomic ◽  
Environmental Distribution ◽  
Content Type ◽  
The World ◽  
Culture Positive

ABSTRACT Burkholderia pseudomallei is present in the environment in many parts of the world and causes the often-fatal disease melioidosis. The sensitive detection and quantification of B. pseudomallei in the environment are a prerequisite for assessing the risk of infection. We recently reported the direct detection of B. pseudomallei in soil samples using a quantitative PCR (qPCR) targeting a single type three secretion system 1 (TTSS1) gene. Here, we extend the qPCR-based analysis of B. pseudomallei in soil by validating novel qPCR gene targets selected from a comparative genomic analysis. Two hundred soil samples from two rice paddies in northeast Thailand were evaluated, of which 47% (94/200) were B. pseudomallei culture positive. The TTSS1 qPCR and two novel qPCR assays that targeted open reading frames (ORFs) BPSS0087 and BPSS0745 exhibited detection rates of 76.5% (153/200), 34.5% (69/200), and 74.5% (150/200), respectively. The combination of TTSS1 and BPSS0745 qPCR increased the detection rate to 90% (180/200). Combining the results of the three qPCR assays and the BPSS1187 nested PCR previously published, all 200 samples were positive by at least one PCR assay. Samples positive by either TTSS1 (n = 153) or BPSS0745 (n = 150) qPCR were more likely to be direct-culture positive, with odds ratios of 4.0 (95% confidence interval [CI], 1.7 to 9.5; P < 0.001) and 9.0 (95% CI, 3.1 to 26.4; P < 0.001), respectively. High B. pseudomallei genome equivalents correlated with high CFU counts by culture. In conclusion, multitarget qPCR improved the B. pseudomallei detection rate in soil samples and predicted culture positivity. This approach has the potential for use as a sensitive environmental screening method for B. pseudomallei. IMPORTANCE The worldwide environmental distribution of the soil bacterium Burkholderia pseudomallei remains to be determined. So far, most environmental studies have relied on culture-based approaches to detect this pathogen. Since current culture methods are laborious, are time consuming, and have limited sensitivity, culture-independent and more sensitive methods are needed. In this study, we show that a B. pseudomallei-specific qPCR approach can detect significantly higher numbers of B. pseudomallei-positive soil samples from areas where it is endemic compared with that from culture. The use of multiple independent B. pseudomallei-specific qPCR targets further increased the detection rate of B. pseudomallei compared with that from single targets. Samples with a high molecular B. pseudomallei load were more likely to be culture positive. We conclude that our quantitative multitarget approach might be useful in defining areas where there is a risk of B. pseudomallei infections in different parts of the world.

scholarly journals Duplex Quantitative PCR Assay for Detection of Haemophilus influenzae That Distinguishes Fucose- and Protein D-Negative Strains

2016 ◽  
Vol 54 (9) ◽  
pp. 2380-2383 ◽  
Author(s):  
Camilla de Gier ◽  
Janessa L. Pickering ◽  
Peter C. Richmond ◽  
Ruth B. Thornton ◽  
Lea-Ann S. Kirkham
Keyword(s):  
Confidence Interval ◽  
Haemophilus Influenzae ◽  
Quantitative Pcr ◽  
Strong Correlation ◽  
Bacterial Species ◽  
Pcr Assay ◽  
Content Type ◽  
Clinical Specimens ◽  
Quantitative Pcr Assay

We have developed a specificHaemophilus influenzaequantitative PCR (qPCR) that also identifies fucose-negative and protein D-negative strains. Analysis of 100H. influenzaeisolates, 28Haemophilus haemolyticusisolates, and 14 other bacterial species revealed 100% sensitivity (95% confidence interval [CI], 96% to 100%) and 100% specificity (95% CI, 92% to 100%) for this assay. The evaluation of 80 clinical specimens demonstrated a strong correlation between semiquantitative culture and the qPCR (P< 0.001).

scholarly journals Presence and Persistence of Coxiella burnetii in the Environments of Goat Farms Associated with a Q Fever Outbreak

2013 ◽  
Vol 79 (5) ◽  
pp. 1697-1703 ◽  
Author(s):  
Gilbert J. Kersh ◽  
Kelly A. Fitzpatrick ◽  
Joshua S. Self ◽  
Rachael A. Priestley ◽  
Aubree J. Kelly ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Quantitative Pcr ◽  
Coxiella Burnetii ◽  
Q Fever ◽  
Human Movement ◽  
Zoonotic Disease ◽  
Content Type ◽  
Air Samples ◽  
Ruminant Livestock

ABSTRACTQ fever is a zoonotic disease caused by inhalation of the bacteriumCoxiella burnetii. Ruminant livestock are common reservoirs forC. burnetii, and bacteria present in aerosols derived from the waste of infected animals can infect humans. The significance of infection from material deposited in the environment versus transmission directly from infected animals is not known. In 2011, an outbreak of Q fever cases on farms in Washington and Montana was associated with infected goats. A study was undertaken to investigate the quantity and spatial distribution ofC. burnetiiin the environment of these goat farms. Soil, vacuum, and sponge samples collected on seven farms epidemiologically linked to the outbreak were tested for the presence ofC. burnetiiDNA by quantitative PCR. Overall, 70.1% of the samples were positive forC. burnetii. All farms had positive samples, but the quantity ofC. burnetiivaried widely between samples and between farms. High quantities ofC. burnetiiDNA were in goat housing/birthing areas, and only small quantities were found in samples collected more than 50 m from these areas. Follow-up sampling at one of the farms 1 year after the outbreak found small quantities ofC. burnetiiDNA in air samples and large quantities ofC. burnetiipersisting in soil and vacuum samples. The results suggest that the highest concentrations of environmentalC. burnetiiare found in goat birthing areas and that contamination of other areas is mostly associated with human movement.

scholarly journals Complete Genome Sequences of Bacillus Phages DirtyBetty and Kida

2017 ◽  
Vol 5 (10) ◽  
Author(s):  
Kelly Flounlacker ◽  
Rachel Miller ◽  
Diana Marquez ◽  
Allison Johnson
Keyword(s):  
Bacillus Thuringiensis ◽  
Bacillus Cereus ◽  
Complete Genome ◽  
Soil Samples ◽  
Genome Sequences ◽  
Content Type ◽  
Double Stranded Dna

ABSTRACT We report here the genome sequences of two bacteriophages of the Bacillus cereus group, DirtyBetty and Kida. These bacteriophages are double-stranded DNA-containing Myoviridae isolated from soil samples using Bacillus thuringiensis subsp. kurstaki as their host bacteria.

scholarly journals Complete Sequences of Two Plasmids Found in a Brazilian Bacillus thuringiensis Serovar israelensis Strain

2019 ◽  
Vol 8 (9) ◽  
Author(s):  
Fabrício S. Campos ◽  
Fernando B. Cerqueira ◽  
Gil R. Santos ◽  
Eliseu J. G. Pereira ◽  
Roberto F. T. Corrêia ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Crucial Role ◽  
Bacterial Genomes ◽  
Content Type ◽  
Complete Sequences

Plasmids play a crucial role in the evolution of bacterial genomes by mediating horizontal gene transfer. In this work, we sequenced two plasmids found in a Brazilian Bacillus thuringiensis serovar israelensis strain which showed 100% nucleotide identities with Bacillus thuringiensis serovar kurstaki plasmids.

scholarly journals Different Hatching Rates of Floodwater Mosquitoes Aedes sticticus, Aedes rossicus and Aedes cinereus from Different Flooded Environments

Insects ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 279
Author(s):  
Anders Lindström ◽  
Disa Eklöf ◽  
Tobias Lilja
Keyword(s):  
Tap Water ◽  
Soil Samples ◽  
Mosquito Larvae ◽  
Retaining Structures ◽  
Retaining Structure ◽  
Large Numbers ◽  
Random Samples ◽  
Nuisance Species ◽  
Flooding Events ◽  
Hatching Rates

In the lower Dalälven region, floodwater mosquitoes cause recurring problems. The main nuisance species is Aedes (Ochlerotatus) sticticus, but large numbers of Aedes (Aedes) rossicus and Aedes (Aedes) cinereus also hatch during flooding events. To increase understanding of which environments in the area give rise to mosquito nuisance, soil samples were taken from 20 locations from four environmental categories: grazed meadows, mowed meadows, unkept open grassland areas and forest areas. In each location 20 soil samples were taken, 10 from random locations and 10 from moisture retaining structures, such as tussocks, shrubs, piles of leaves, logs, and roots. The soil samples were soaked with tap water in the lab, and mosquito larvae were collected and allowed to develop to adult mosquitoes for species identification. Fewer larvae hatched from mowed areas and more larvae hatched from moisture retaining structure samples than random samples. The results showed that Aedes cinereus mostly hatch from grazed and unkept areas and hatched as much from random samples as from structures, whereas Aedes sticticus and Aedes rossicus hatched from open unkept and forest areas and hatch significantly more from structure samples. When the moisture retaining structures in open unkept areas where Aedes sticticus hatched were identified it was clear that they hatched predominantly from willow shrubs that offered shade. The results suggest that Ae. sticticus and Ae. cinereus favor different flooded environments for oviposition.

scholarly journals Endotoxemia as a Diagnostic Tool for Patients with Suspected Bacteremia Caused by Gram-Negative Organisms: a Meta-Analysis of 4 Decades of Studies

2015 ◽  
Vol 53 (4) ◽  
pp. 1183-1191 ◽  
Author(s):  
James C. Hurley ◽  
Piotr Nowak ◽  
Lars Öhrmalm ◽  
Charalambos Gogos ◽  
Apostolos Armaganidis ◽  
...  
Keyword(s):  
Confidence Interval ◽  
Meta Analysis ◽  
Inclusion Criteria ◽  
Summary Receiver Operating Characteristic ◽  
Detection Rates ◽  
Gram Negative ◽  
Content Type ◽  
E Coli ◽  
Patient Groups ◽  
Gram Negative Organisms

The clinical significance of endotoxin detection in blood has been evaluated for a broad range of patient groups in over 40 studies published over 4 decades. The influences of Gram-negative (GN) bacteremia species type and patient inclusion criteria on endotoxemia detection rates in published studies remain unclear. Studies were identified after a literature search and manual reviews of article bibliographies, together with a direct approach to authors of potentially eligible studies for data clarifications. The concordance between GN bacteremia and endotoxemia expressed as the summary diagnostic odds ratios (DORs) was derived for three GN bacteremia categories across eligible studies by using a hierarchical summary receiver operating characteristic (HSROC) method. Forty-two studies met broad inclusion criteria, with between 2 and 173 GN bacteremias in each study. Among all 42 studies, the DORs (95% confidence interval) were 3.2 (1.7 to 6.0) and 5.8 (2.4 to 13.7) in association with GN bacteremias withEscherichia coliand those withPseudomonas aeruginosa, respectively. Among 12 studies of patients with sepsis, the proportion of endotoxemia positivity (95% confidence interval) among patients withP. aeruginosabacteremia (69% [57 to 79%];P= 0.004) or withProteusbacteremia (76% [51 to 91%];P= 0.04) was significantly higher than that among patients without GN bacteremia (49% [33 to 64%]), but this was not so for patients bacteremic withE. coli(57% [40 to 73%];P= 0.55). Among studies of the sepsis patient group, the concordance of endotoxemia with GN bacteremia was surprisingly weak, especially forE. coliGN bacteremia.

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