scholarly journals Diagnosis and Stratification of Pseudomonas aeruginosa Infected Patients by Immunochemical Quantitative Determination of Pyocyanin From Clinical Bacterial Isolates

2021 ◽  
Vol 11 ◽  
Author(s):  
Barbara Rodriguez-Urretavizcaya ◽  
Nuria Pascual ◽  
Carme Pastells ◽  
Maria Teresa Martin-Gomez ◽  
Lluïsa Vilaplana ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Limit Of Detection ◽  
Release Kinetics ◽  
Clinical Isolates ◽  
Clinical Samples ◽  
Mueller Hinton ◽  
Highly Sensitive ◽  
Kinetics Of ◽  
Selection Of

The development of a highly sensitive, specific, and reliable immunochemical assay to detect pyocyanin (PYO), one of the most important virulence factors (VFs) of Pseudomonas aeruginosa, is here reported. The assay uses a high-affinity monoclonal antibody (mAb; C.9.1.9.1.1.2.2.) raised against 1-hydroxyphenazine (1-OHphz) hapten derivatives (PC1; a 1:1 mixture of 9-hydroxy- and 6-hydroxy-phenazine-2-carobxylic acids). Selective screening using PYO and 1-OHphz on several cloning cycles allowed the selection of a clone able to detect PYO at low concentration levels. The microplate-based ELISA developed is able to achieve a limit of detection (LoD) of 0.07 nM, which is much lower than the concentrations reported to be found in clinical samples (130 μM in sputa and 2.8 μM in ear secretions). The ELISA has allowed the investigation of the release kinetics of PYO and 1-OHphz (the main metabolite of PYO) of clinical isolates obtained from P. aeruginosa-infected patients and cultured in Mueller–Hinton medium. Significant differences have been found between clinical isolates obtained from patients with an acute or a chronic infection (~6,000 nM vs. ~8 nM of PYO content, respectively) corroborated by the analysis of PYO/1-OHphz levels released by 37 clinical isolates obtained from infected patients at different stages. In all cases, the levels of 1-OHphz were much lower than those of PYO (at the highest levels 6,000 nM vs. 300 nM for PYO vs. 1-OHphz, respectively). The results found point to a real potential of PYO as a biomarker of P. aeruginosa infection and the possibility to use such VF also as a biomarker for patient stratification[2] and for an effective management of these kinds of infections.

scholarly journals Immobilization of Pseudomonas aeruginosa static biomass on eggshell powder for on-line preconcentration and determination of Cr (VI)

2020 ◽  
Vol 18 (1) ◽  
pp. 303-313 ◽  
Author(s):  
Aamir Rasheed ◽  
Tahseen Ghous ◽  
Sumaira Mumtaz ◽  
Muhammad Nadeem Zafar ◽  
Kalsoom Akhter ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Low Cost ◽  
Colorimetric Detection ◽  
Time Flow ◽  
Highly Sensitive ◽  
Glass Column ◽  
On Line ◽  
Preconcentration Time ◽  
Ultra Trace

AbstractIn the present work, a novel continuous flow system (CFS) is developed for the preconcentration and determination of Cr (VI) using Pseudomonas aeruginosa static biomass immobilized onto an effective and low-cost solid support of powdered eggshells. A mini glass column packed with the immobilized biosorbent is incorporated in a CFS for the preconcentration and determination of Cr (VI) from aqueous solutions. The method is based on preconcentration, washing and elution steps followed by colorimetric detection with 1,5-diphenyl carbazide in sulphuric acid. The effects of several variables such as pH, retention time, flow rate, eluent concentration and loaded volume are studied. Under optimal conditions, the CFS method has a linear range between 10 and 100 μg L-1 and a detection limit of 6.25 μg L-1 for the determination of Cr (VI). The sampling frequency is 10 samples per hour with a preconcentration time of 5 mins. Furthermore, after washing with a 0.1 M buffer (pH 3.0), the activity of the biosorbent is regenerated and remained comparable for more than 200 cycles. Scanning electron microscopy reveals a successful immobilization of biomass on eggshells powder and precipitation of Cr (VI) on the bacterial cell surface. The proposed method proves highly sensitive and could be suitable for the determination of Cr (VI) at an ultra-trace level.

scholarly journals Gelatin Beads/Hemp Hurd as pH Sensitive Devices for Delivery of Eugenol as Green Pesticide

2021 ◽  
Author(s):  
Gianluca Viscusi ◽  
Giuliana Gorrasi
Keyword(s):  
Release Kinetics ◽  
Barrier Properties ◽  
Ph Sensitive ◽  
Release Behavior ◽  
Sorption Coefficient ◽  
Highly Sensitive ◽  
Mean Diameter ◽  
Ph Conditions ◽  
Kinetics Of ◽  
Hemp Hurd

AbstractIn this paper gelatin beads reinforced with natural hemp hurd have been produced as pH sensitive devices for the release of eugenol, as green pesticide. The composites beads, with a mean diameter of about 1 mm, were obtained by polymer droplet gelation in sunflower oil. Thermal properties were evaluated showing no noticeable difference after the introduction of hemp hurd. Barrier properties demonstrated an improvement of hydrophobization. The introduction of 5% w/w of hemp hurd led to a reduction of sorption coefficient of about 85% compared to unloaded gelatin beads. Besides, the diffusion coefficient decreased, introducing 5% w/w of hemp hurd, from 8.91 × 10−7 to 0.77 × 10−7 cm2/s. Swelling and dissolution phenomena of gelatin beads were studied as function of pH. The swelling of gelatin beads raised as pH increased up to 2.3 g/g, 9.1 g/g and 27.33 g/g at pH 3, 7 and 12, respectively. The dissolution rate changed from 0.034 at pH 3 to 0.077 h−1 at pH 12. Release kinetics of eugenol at different pH conditions were studied. The released eugenol after 24 h is 98%, 91%, 81 and 63% w/w (pH 3), 87%, 62%, 37 and 32 wt% (pH 7) and 81%, 68%, 60 and 52 wt% (pH 12) for unloaded gelatin beads and gelatin beads with 1%, 3 and 5% of hemp hurd, respectively. The eugenol release behavior was demonstrated to be highly sensitive to the pH release medium, which allows to tune such devices as green pesticide release systems in soils with different level of acidity/basicity.

scholarly journals HCV Detection, Discrimination, and Genotyping Technologies

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3423 ◽  
Author(s):  
Shrikant Warkad ◽  
Satish Nimse ◽  
Keum-Soo Song ◽  
Taisun Kim
Keyword(s):  
Hepatitis C ◽  
Hcv Infection ◽  
World Health ◽  
Clinical Samples ◽  
Infected People ◽  
Advantages And Disadvantages ◽  
Highly Sensitive ◽  
The World ◽  
Health Organization

According to the World Health Organization (WHO), 71 million people were living with Hepatitis C virus (HCV) infection worldwide in 2015. Each year, about 399,000 HCV-infected people succumb to cirrhosis, hepatocellular carcinoma, and liver failure. Therefore, screening of HCV infection with simple, rapid, but highly sensitive and specific methods can help to curb the global burden on HCV healthcare. Apart from the determination of viral load/viral clearance, the identification of specific HCV genotype is also critical for successful treatment of hepatitis C. This critical review focuses on the technologies used for the detection, discrimination, and genotyping of HCV in clinical samples. This article also focuses on advantages and disadvantages of the reported methods used for HCV detection, quantification, and genotyping.

scholarly journals Evaluation of Antibiotic Resistance Pattern, Alginate and Biofilm Production in Clinical Isolates of Pseudomonas aeruginosa

2021 ◽  
Author(s):  
Fateme DAVARZANI ◽  
Navid SAIDI ◽  
Saeed BESHARATI ◽  
Horieh SADERI ◽  
Iraj RASOOLI ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Bacterial Resistance ◽  
Antimicrobial Agents ◽  
Clinical Isolates ◽  
Diffusion Method ◽  
Clinical Samples ◽  
Resistance Pattern ◽  
Alginate Production ◽  
Opportunistic Bacteria

Background: Pseudomonas aeruginosa is one of the most common opportunistic bacteria causing nosocomial infections, which has significant resistance to antimicrobial agents. This bacterium is a biofilm and alginate producer. Biofilm increases the bacterial resistance to antibiotics and the immune system. Therefore, the present study was conducted to investigate the biofilm formation, alginate production and antimicrobial resistance patterns in the clinical isolates of P. aeruginosa. Methods: One hundred isolates of P. aeruginosa were collected during the study period (from Dec 2017 to Jul 2018) from different clinical samples of the patients admitted to Milad and Pars Hospitals at Tehran, Iran. Isolates were identified and confirmed by phenotypic and genotypic methods. Antimicrobial susceptibility was specified by the disk diffusion method. Biofilm formation and alginate production were measured by microtiter plate and carbazole assay, respectively. Results: Sixteen isolates were resistant to all the 12 studied antibiotics. Moreover, 31 isolates were MultidrugResistant (MDR). The highest resistance rate was related to ofloxacin (36 isolates) and the least resistance was related to piperacillin-tazobactam (21 isolates). All the isolates could produce the biofilm and alginate. The number of isolates producing strong, medium and weak biofilms was equal to 34, 52, and 14, respectively. Alginate production was more than 400 μg/ml in 39 isolates, 250-400 μg/ml in 51 isolates and less than 250 μg/ml in 10 isolates. Conclusion: High prevalence of MDR, biofilm formation, and alginate production were observed among the clinical isolates of P. aeruginosa. The results also showed a significant relationship between the amount of alginate production and the level of biofilm formation.

scholarly journals Acquisition of multidrug resistance transposon Tn6061 and IS6100-mediated large chromosomal inversions in Pseudomonas aeruginosa clinical isolates

Microbiology ◽  
2010 ◽  
Vol 156 (5) ◽  
pp. 1448-1458 ◽  
Author(s):  
Sébastien Coyne ◽  
Patrice Courvalin ◽  
Marc Galimand
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Multidrug Resistance ◽  
Opportunistic Pathogen ◽  
Clinical Isolates ◽  
Chromosomal Inversions ◽  
Gene Acquisition ◽  
Drug Classes ◽  
Horizontal Acquisition

Pseudomonas aeruginosa is a major human opportunistic pathogen, especially for patients in intensive care units or with cystic fibrosis. Multidrug resistance is a common feature of this species. In a previous study we detected the ant(4′)-IIb gene in six multiresistant clinical isolates of P. aeruginosa, and determination of the environment of the gene led to characterization of Tn6061. This 26 586 bp element, a member of the Tn3 family of transposons, carried 10 genes conferring resistance to six drug classes. The ant(4′)-IIb sequence was flanked by directly repeated copies of ISCR6 in all but one of the strains studied, consistent with ISCR6-mediated gene acquisition. Tn6061 was chromosomally located in six strains and plasmid-borne in the remaining isolate, suggesting horizontal acquisition. Duplication-insertion of IS6100, that ended Tn6061, was responsible for large chromosomal inversions. Acquisition of Tn6061 and chromosomal inversions are further examples of intricate mechanisms that contribute to the genome plasticity of P. aeruginosa.

scholarly journals Determination of N-acylhomoserine lactones of Pseudomonas aeruginosa in clinical samples from dogs with otitis externa

2016 ◽  
Vol 12 (1) ◽  
Author(s):  
Darja Kušar ◽  
Karin Šrimpf ◽  
Petra Isaković ◽  
Lina Kalšek ◽  
Javid Hosseini ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Otitis Externa ◽  
Clinical Samples

scholarly journals Comparative evaluation of published cytomegalovirus primers for rapid real-time PCR: which are the most sensitive?

2009 ◽  
Vol 58 (7) ◽  
pp. 878-883 ◽  
Author(s):  
Wafa Habbal ◽  
Fawza Monem ◽  
Barbara C. Gärtner
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Clinical Isolates ◽  
Clinical Samples ◽  
Analytical Sensitivity ◽  
Pcr Product ◽  
Highly Sensitive ◽  
Primer Sets ◽  
Analytical Sensitivities ◽  
Strain Ad169

Standardization of human cytomegalovirus (CMV) PCR is highly recommended. As primer design is essential for PCR sensitivity, this study evaluated all published CMV primer pairs to identify the most sensitive for single-round real-time PCR. PubMed (1993–2004) was searched for original papers aimed at CMV PCR. Fifty-seven papers were identified revealing 82 different primer pairs. Of these, 17 primer sets were selected for empirical study, as they were either used in real-time PCR or were evaluated comparatively by conventional PCR. After optimizing the PCR conditions, these primer sets were evaluated by real-time PCR using a SYBR Green format. Analytical sensitivities were assessed by testing the reference standard CMV strain AD169. A blast search was performed to identify mismatches with published sequences. Additionally, 60 clinical samples were tested with the three primer sets showing highest analytical sensitivity and the best match to all CMV strains. Three primer sets located in the glycoprotein B (UL55) gene region were found to be the most sensitive using strain AD169. However, two of these showed a considerable number of mismatches with clinical isolates in a blast search. Instead, two other pairs from the lower matrix phosphoprotein (UL83) gene and DNA polymerase (UL54) gene showed reasonable sensitivity and no mismatches with clinical isolates. These three pairs were further tested with clinical samples, which indicated that the two primer sets from UL55 and UL54 were the most sensitive. Interestingly, the analytical sensitivity of the PCR was inversely correlated with the size of the PCR product. In conclusion, these two primer pairs are recommended for a standardized, highly sensitive, real-time PCR.

scholarly journals Characterization of clinical isolates of Pseudomonas aeruginosa heterogeneously resistant to carbapenems

2007 ◽  
Vol 56 (1) ◽  
pp. 66-70 ◽  
Author(s):  
Spyros Pournaras ◽  
Alexandros Ikonomidis ◽  
Antonios Markogiannakis ◽  
Nicholas Spanakis ◽  
Antonios N. Maniatis ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Population Analysis ◽  
Growth Curves ◽  
Clinical Isolates ◽  
Lag Phase ◽  
Carbapenem Resistant ◽  
One Step ◽  
Agar Dilution ◽  
Resistant Mutants ◽  
Selection Of

Fourteen apparently carbapenem-susceptible Pseudomonas aeruginosa clinical isolates that exhibited colonies within the inhibition zone around carbapenem discs were analysed. MICs of carbapenems were determined and the isolates were genotyped by PFGE. Population analysis, one-step selection of carbapenem-resistant mutants and growth curves of progenitors and carbapenem-resistant subpopulations were performed. Agar dilution MICs of imipenem and meropenem ranged from 0.5 to 4 mg l−1 and from 0.25 to 2 mg l−1, respectively. Population analysis confirmed subpopulations that grew in concentrations of up to 18 mg l−1 and 12 mg l−1 of imipenem and meropenem, respectively, at frequencies ranging from 6.9×10−5 to 1.1×10−7, suggesting that they might not be detected by standard agar dilution MIC testing. The minority subpopulations exhibited MICs for imipenem ranging from 10 to 20 mg l−1 and for meropenem from 4 to 14 mg l−1. The one-step 8 mg l−1 selection of imipenem-resistant mutants test showed growth in all isolates at frequencies ranging from 3.8×10−4 to 5.1×10−7. Growth curves revealed a prolonged lag phase and a short exponential phase for the heterogeneous subpopulations compared with their respective native subpopulations. These findings may be indicative that the use of carbapenems can lead to selection of P. aeruginosa resistant subpopulations that subsequently cause infections and result in treatment failure.

scholarly journals Tannic Acid-Capped Gold Nanoparticles as a Novel Nanozyme for Colorimetric Determination of Pb2+ Ions

Chemosensors ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 332
Author(s):  
Kseniya V. Serebrennikova ◽  
Nadezhda S. Komova ◽  
Anna N. Berlina ◽  
Anatoly V. Zherdev ◽  
Boris B. Dzantiev
Keyword(s):  
Gold Nanoparticles ◽  
Tannic Acid ◽  
Oxidation Reaction ◽  
Limit Of Detection ◽  
Colorimetric Sensor ◽  
Spring Water ◽  
Colorimetric Determination ◽  
Highly Sensitive ◽  
Maximal Sensitivity

In this study, tannic acid-modified gold nanoparticles were found to have superior nanozyme activity and catalyze the oxidation reaction of 3,3′,5,5′-tetramethylbenzidine in the presence of hydrogen peroxide. Enhancing the catalytic activity of the nanozyme by Pb2+ ions caused by selectively binding metal ions by the tannic acid-capped surface of gold nanoparticles makes them an ideal colorimetric probe for Pb2+. The parameters of the reaction, including pH, incubation time, and concentration of components, were optimized to reach maximal sensitivity of Pb2+ detection. The absorption change is directly proportional to the Pb2+ concentration and allows the determination of Pb2+ ions within 10 min. The colorimetric sensor is characterized by a wide linear range from 25 to 500 ng×mL−1 with a low limit of detection of 11.3 ng×mL−1. The highly sensitive and selective Pb2+ detection in tap, drinking, and spring water revealed the feasibility and applicability of the developed colorimetric sensor.

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