Biodétection de Legionella pneumophila par biocapteur à photocorrosion digitale à base de peptide antimicrobien

La détection de bactéries pathogènes par culture microbienne est lente, nécessite un milieu de culture spécifique pour garantir la croissance de certaines souches bactériennes fastidieuses telle que Legionella pneumophila (L. pneumophila) et en plus pourrait ne pas déceler les bactéries viables mais non cultivables mais restant dangereuse en termes de pathogénicité. Par conséquent, l’usage de biocapteurs pour la détection de L. pneumophila serait, potentiellement, une approche attrayante permettant une détection précise et rapide. Cependant, la sensibilité et la spécificité des biocapteurs dépendent fortement des molécules de bioreconnaissance utilisées. Jusqu'à présent, différents ligands tels que les anticorps, les enzymes, les acides nucléiques fonctionnels (aptamères) et les bactériophages ont été utilisés comme éléments de bioreconnaissance. En raison de leur haute spécificité, Les anticorps de mammifères ont été largement employés pour le développement de divers biocapteurs. Cependant, les anticorps sont connus pour souffrir de la variabilité des lots produits et d'une stabilité limitée, ce qui réduit l'usage et la constance des performances des biocapteurs à base d'anticorps. Au cours des dernières années, les peptides antimicrobiens (PAM) ont été de plus en plus investigués pour des applications thérapeutiques en plus d’être considérés comme des ligands de bioreconnaissance prometteurs en raison de leur grande stabilité et leurs fortes réactivités aux bactéries. Dans le but d’améliorer les performances du biocapteur à DIP, notre hypothèse reposait sur l’usage de bioarchitectures à base de PAM à courte séquence pour une capture efficace des bactéries et une détection considérablement améliorée en raison du transfert de charge plus facilitée vers dans la biopuce à base de semiconducteur III-V. Dans la première phase du projet, nous avons évalué un biocapteur à DIP consistant en une puce d’arséniure de gallium/arséniure de gallium aluminium (GaAs/AlGaAs) fonctionnalisée par le warnericine RK pour la détection directe in situ de L. pneumophila dans l’eau. Nous avons démontré une détection linéaire de L. pneumophila pour des concentrations allant de 103 à 106 CFU/mL. De plus, le nombre relativement important d'interfaces constituant la bioarchitecture d’un tel biocapteur pourrait affecter sa reproductibilité et sa sensibilité. Dans ce cas, la couche de bioreconnaissance est plus mince (~ 2 nm) permettant une distance plus courte entre les bactéries et la surface du biocapteur, ce qui pourrait jouer un rôle important dans la promotion du transfert de charge entre les bactéries et la biopuce, et ainsi nous avons pu démontrer une détection efficace de L. pneumophila à une concentration de 2 x 102 CFU/mL. Cette configuration a permis d’atteindre des LODs de 50 et 100 UFC/mL, respectivement pour de légionnelle dans du PBS et collectées d’échantillons d’eau de tour de refroidissement. Nous avons observé une détection sélective de L. pneumophila sérogroupe 1 (SG1) comparé au sérogroupe 5 (SG 5). Les biocapteurs à photocorrosion digitale (DIP) en configuration sandwich PAM et Ab pourraient être une approche prometteuse pour développer un biocapteur à faible coût, hautement sensible et spécifique pour la détection rapide de L. pneumophila dans l’eau.Abstract: Culture based detection of pathogenic bacteria is time consuming, and needs specific culture medium to identify bacterial strains such as Legionella pneumophila (L. pneumophila) which does not flourish in typical growth medium. Culture based methods cannot detect viable but unculturable bacteria. Therefore, the detection of L. pneumophila with biosensors potentially could be an attractive approach enabling accurate and rapid detection. The sensitivity and specificity of biosensors depend critically on the biorecognition probes employed for the detection. Until now, different elements such as antibodies, enzymes, functional nucleic acids (aptamers) and bacteriophages have been utilized as biorecognition elements. Due to high specificity of antibodies, and the advanced technology of their production, mammalian antibodies have been widely investigated for the development of various biosensors. However, mammalian antibodies are known to suffer from batch-to-batch variation, as well as limited stability, which could reduce the consistent utility of the proposed biosensors. In recent years, antimicrobial peptides (AMPs) have been increasingly investigated for their therapeutic applications. At the same time, AMPs are considered as promising biorecognition ligands due to their high stability and multiple niches for capturing bacteria. The hypothesis was that AMP-based bioarchitectures allows for highly efficient capturing of bacteria, and the short length of the AMP would significantly enhance detection due to limited obstructive charge transfer in the charge sensing biosensor. In the first phase of the project, we investigated a warnericin RK AMP functionalized gallium arsenide/aluminum gallium arsenide (GaAs/AlGaAs) photonic biosensor for direct detection of L. pneumophila in water environments. This approach allowed for detecting a low to high concentration of L. pneumophila (103 to 106 CFU/mL) with a 103 CFU/mL limit of detection (LOD). In addition, a relatively large number of interfaces constituting the architecture of such biosensors could affect their reproducibility and sensitivity. A thinner biorecognition layer (~2 nm) resulted in a shorter distance between bacteria and the biosensor surface, which played important role in promoting charge transfer between bacteria and biochip. L. pneumophila was detected at concentrations as low of 2 x 102 CFU/mL. This configuration allowed the detection sensitivity of L. pneumophila as low as 50 CFU/mL and 100 CFU/mL in clean water and water originated from cooling tower, respectively, along with the selective detection of whole cell L. pneumophila serogroup 1 (SG1) and serogroup 5 (SG5). The proposed AMP and Ab conjugated sandwich architecture with digital photocorrosion (DIP) biosensors is a promising approach for developing low cost, highly sensitive and specific biosensors for rapid detection of L. pneumophila in water environments

Outcomes of early active mobilization after surgical repair of injured extensor tendon of hand and forearm

Background: Extensor tendon injuries in the hand and forearm, if left untreated, can significantly impair backhand function. Timely and effective treatment is crucial. Recent evidence suggests that early active mobilization post-surgery yields better short-term outcomes, with less disparity in long-term results. Methods: This prospective observational study was conducted at the department of orthopedic surgery, BSMMU, Dhaka, Bangladesh, from March 2014 to August 2016, with a total of 40 patients. Results: The study evaluated the efficacy of early active mobilization following surgical repair of extensor tendon injuries in zones V-VIII of the hand and forearm. At 12 weeks post-surgery, 75% of patients reported no pain, increasing to 90% at 6 months and stabilizing at 85% by 12 months. Furthermore, 75% of patients regained a range of motion greater than 120 degrees at 6 months, with 60% maintaining this at 12 months. Notably, 90% of the patients maintained normal grip strength at both 6 and 12 months. Final assessments using the Mayo wrist score showed satisfactory outcomes for 70% of patients at 12 weeks, 90% at 6 months, and 95% at 12 months. The Dargan criteria echoed these positive results, with satisfaction rates of 80% at 12 weeks, 90% at 6 months, and 95% at 12 months. Complications were minimal, including superficial skin infections (5%), hypertrophic scars (10%), and tendon rupture (5%). Conclusions: The study concludes that early active mobilization, complemented by a simple static splint, facilitates faster recovery, full range of motion, improved grip strength, and earlier return to work in the early postoperative period

Isolation, Identification and In Vitro Antibiotic Sensitivity Pattern of Citrus Canker Causing Organism Xanthomonas axonopodis.

Background: Xanthomonas axonopodis or X. axonopodis is the devastating causal organism of citrus canker, widely spread bacterial disease of plants from both epidemiological and economic points of view. Furthermore, the situation is worsening by the advent of increased antibiotic resistance among this bacteria. The major interests of this study were isolation, identification and in vitro antibiotic sensitivity pattern of the causal organism. Besides, herbal sensitivity of those organisms was also tested. Methods: In this study, 9 isolates of the organism were identified based on morphological, cultural and biochemical characteristics. All the isolates were tested for antibiotic sensitivity against 5 commonly used antibiotics namely, cefotaxime, bacitracin, chloramphenicol, streptomycin and gentamycin. Results: X. axonopodis was found 100% resistant to cefotaxime and 77.77% to bacitracin. Chloramphenicol was found most effective as all the isolates were sensitive to it. The herbal sensitivity of X. axonopodis was tested with the plant extract of Allium cepa, Allium sativum, Litchi chinensis, Vitis amurensis and Syzygium cumini. Among the plant extracts, the pathogens were found most sensitive to Allium sativum and Syzygium cumini and resistant to V. amurensis. Conclusion: The study showed herbal treatment can be implicated for the disease citrus canker caused by antibiotic resistant X. axonopodis in future

Microbial lipid extraction from Lipomyces starkeyi using irreversible electroporation

The aim of the study was to investigate the feasibility of using irreversible electroporation (EP) as a microbial cell disruption technique to extract intracellular lipid within short time and in an eco-friendly manner. An EP circuit was designed and fabricated to obtain 4 kV with frequency of 100 Hz of square waves. The yeast cells of Lipomyces starkeyi (L. starkeyi) were treated by EP for 2-10 min where the distance between electrodes was maintained at 2, 4, and 6 cm. Colony forming units (CFU) were counted to observe the cell viability under the high voltage electric field. The forces of the pulsing electric field caused significant damage to the cell wall of L. starkeyi and the disruption of microbial cells was visualized by field emission scanning electron microscopic (FESEM) image. After breaking the cell wall, lipid was extracted and measured to assess the efficiency of EP over other techniques. The extent of cell inactivation was up to 95% when the electrodes were placed at the distance of 2 cm, which provided high treatment intensity (36.7 kWh m ). At this condition, maximum lipid (63 mg g ) was extracted when the biomass was treated for 10 min. During the comparison, EP could extract 31.88% lipid while the amount was 11.89% for ultrasonic and 16.8% for Fenton's reagent. The results recommend that the EP is a promising technique for lowering the time and solvent usage for lipid extraction from microbial biomass. © 2018 American Institute of Chemical Engineers Biotechnol

Artificial intelligence-enabled rapid and symptom-based medication recommendation system (COV-MED) for the COVID-19 patients

In a general COVID-19 population in Cox’s Bazar, Bangladesh, we developed a medication recommendation system based on clinical information from the electronic medical record (EMR). Our goal was also to enable deep learning (DL) strategies to quickly assist physicians and COVID-19 patients by recommending necessary medications. The general demographic data, clinical symptoms, basic clinical tests, and drug information of 8953 patients were used to create a dataset. The learning model in this COVID-MED model was created using Keras (an open-source artificial neural network library) to solve regression problems. In this study, a sequential model was adopted. In order to improve the prediction capability and achieve global minima quickly and smoothly, the COVID-MED model incorporates an adaptive optimizer dubbed Adam. The model calculated a mean absolute error of 0.0037, a mean squared error of 0.000035, and a root mean squared error of 0.0059. The model predicts the output medications, such as injections or other oral medications, with around 99% accuracy. These findings show that medication can be predicted using information from the EMR. Similar models allow for patient-specific decision support to help prevent medication errors in diseases other than COVID-19

Construction of copy number variation landscape and characterization of associated genes in a Bangladeshi cohort of neurodevelopmental disorders

Introduction: Copy number variations (CNVs) play a critical role in the pathogenesis of neurodevelopmental disorders (NDD) among children. In this study, we aim to identify clinically relevant CNVs, genes and their phenotypic characteristics in an ethnically underrepresented homogenous population of Bangladesh. Methods: We have conducted chromosomal microarray analysis (CMA) for 212 NDD patients with male to female ratio of 2.2:1.0 to identify rare CNVs. To identify candidate genes within the rare CNVs, gene constraint metrics [i.e., “Critical-Exon Genes (CEGs)”] were applied to the population data. Autism Diagnostic Observation Schedule-Second Edition (ADOS-2) was followed in a subset of 95 NDD patients to assess the severity of autism and all statistical tests were performed using the R package. Results: Of all the samples assayed, 12.26% (26/212) and 57.08% (121/212) patients carried pathogenic and variant of uncertain significance (VOUS) CNVs, respectively. While 2.83% (6/212) patients’ pathogenic CNVs were found to be located in the subtelomeric regions. Further burden test identified females are significant carriers of pathogenic CNVs compared to males (OR = 4.2; p = 0.0007). We have observed an increased number of Loss of heterozygosity (LOH) within cases with 23.85% (26/109) consanguineous parents. Our analyses on imprinting genes show, 36 LOH variants disrupting 69 unique imprinted genes and classified these variants as VOUS. ADOS-2 subset shows severe social communication deficit (p = 0.014) and overall ASD symptoms severity (p = 0.026) among the patients carrying duplication CNV compared to the CNV negative group. Candidate gene analysis identified 153 unique CEGs in pathogenic CNVs and 31 in VOUS. Of the unique genes, 18 genes were found to be in smaller (<1 MB) focal CNVs in our NDD cohort and we identified PSMC3 gene as a strong candidate gene for Autism Spectrum Disorder (ASD). Moreover, we hypothesized that KMT2B gene duplication might be associated with intellectual disability. Conclusion: Our results show the utility of CMA for precise genetic diagnosis and its integration into the diagnosis, therapy and management of NDD patients

The influence of microbial mutualistic interactions and biofilm formation on the performance microbial fuel cell

Microbial fuel cell (MFC) is an electrochemical device that directly converts chemical energy of wastes into electricity by the metabolic activity of microorganisms. The performance of MFC can be affected by several key parameters such as reactor configurations, electrode materials, electrode surface area, membrane, biofilm thickness, and inoculum. Among them, the microbial community composition and the anode biofilm severely influence the performance of MFC. To prepare effective inoculum, the choice of microorganisms should be based on their ability to utilize complex substrates and the electrogenic properties. In this context, the performance of targeted pure cultures (Klebsiella variicola, Klbesiella pneumonia, Bacillus cereus and Pseudomonas aeruginosa) were investigated in palm oil mill effluent (POME) driven MFC. The targeted bacteria were isolated and characterized using BIOLOG gene III, polymerase chain reaction (PCR) and sequencing analysis. The effect of time-course biofilm formation by the microorganisms on MFC performance was visualized using field emission electron microscopy (FESEM) and characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) analysis. The accumulation of dead cells in the multilayer biofilm at the vicinity of the electrode surface over time within the anode biofilm was found to be particularly detrimental to current generation that increased the charge transfer and diffusion resistances confirmed by EIS. Flow induced shear stresses and ultrasound-assisted methods were employed to revitalize the biofilm by removing inert biomass for the maintenance of stable power in MFCs. The hydrodynamic shear stress of 9.34 mPa and the 30 min of ultrasound treatment (20 kHz) successfully reduced the thickness of biofilm thus it revitalized within a short time by increasing the cell growth rate of the biofilm. The mechanism of electron transfer was elucidated using CV analysis. Furthermore, the co-culture and mixed cultures inoculum was developed using targeted bacteria (Klebsiella variicola and Bacillus cereus, Klebsiella variicola and Pseudomonas aeruginosa, Bacillus cereus and Pseudomonas aeruginosa, Klebsiella variicola and Bacillus cereus and Pseudomonas aeruginosa). The highest power density of 14.78 W/m3 was achieved by Pseudomonas aeruginosa and Klebsiella variicola co-culture inoculum due to their synergistic relationships which are inter-linked via fermentation-based metabolite. Besides, the interaction of Klebsiella variicola and Bacillus cereus positively influenced the power generation and the coculture inoculum obtained maximum power density of 11.78 W/m3 whereas the antagonistic relationship was witnessed for Bacillus cereus and Pseudomonas aeruginosa. Apart from that the performance of Klebsiella variicola and Pseudomonas aeruginosa co-culture was optimized with respect of operational parameters (substrate concentration, different ratio of microorganisms, pH and time) by using response surface methodology (RSM). The inoculum composition (different ratios of Klebsiella variicola and Pseudomonas aeruginosa) played a crucial role in simultaneous power generation and chemical oxygen demand (COD) removal from POME. These findings demonstrate that the synergistic interaction of microorganisms in inoculum and their subsequent effective biofilm formation are crucial to achieve the enhanced power generation in MFCs that can potentially be implemented for POME treatment

Psychometric evaluation of an interview-administered version of the WHOQOL-BREF questionnaire for use in a cross-sectional study of a rural district in Bangladesh: an application of Rasch analysis

Abstract Background This study aimed to validate the psychometric properties of the World Health Organization Quality of Life Instrument, Short Form (WHOQOL-BREF) questionnaire for use in a rural district of Bangladesh. Methods This cross-sectional study recruited a multi-stage cluster random sample of 2425 participants from the rural district Narail of Bangladesh in May–July 2017. Rasch analysis was carried out using the sampled participants, as well as multiple validation random sub-samples of 300 participants, to validate four domains of the WHOQOL-BREF questionnaire: physical, psychological, social and environmental. Results The original WHOQOL-BREF appeared to be a poor fit for both sampled and sub-sampled group of participants in Narail district in all underlying domains: physical, psychological, social and environmental. Two items (sleep and work capacity) from the physical domain, two items (personal belief and negative feelings) from the psychological domain and three items (home environment, health care and transport) from the environment domain were excluded for goodness of fit of the Rasch model. The social domain exhibited reasonably reliable fitness while fulfilling all the assumptions of the Rasch model. A modified version of the WHOQOL-BREF questionnaire using five-items for the physical ( χ202 {\upchi}_{(20)}^2 = 36.47, p = 0.013, Person Separation Index (PSI) = 0.773), four-items for the psychological ( χ162 {\upchi}_{(16)}^2 = 28.30, p = 0.029, PSI = 0.708) and five-items for the environmental ( χ202 {\upchi}_{(20)}^2 = 36.97, p = 0.011, PSI = 0.804) domain was applied, which showed adequate internal consistency, reliability, unidimensionality, and similar functioning for different age-sex distributions. Conclusions The modified WHOQOL-BREF questionnaire translated into Bengali language appeared to be a valid tool for measuring quality of life in a typical rural district in Bangladesh. Despite some limitations of the modified WHOQOL-BREF questionnaire, further application of Rasch analysis using this version or an improved one in other representative rural areas of Bangladesh is recommended to assess the external validity of the outcomes of this study and to determine the efficacy of this tool to measure the quality of life at the national rural level

Lowering blood pressure by changing lifestyle through a motivational education program: a cluster randomized controlled trial study protocol

Abstract Background High blood pressure is an independent risk factor of cardiovascular disease (CVD) and is a major cause of disability and death. Managing a healthy lifestyle has been shown to reduce blood pressure and improve health outcomes. We aim to investigate the effectiveness of a lifestyle modification intervention program for lowering blood pressure in a rural area of Bangladesh. Methods A single-center cluster randomized controlled trial (RCT). The study will be conducted for 6 months, a total of 300 participants of age 30 to 75 years with 150 adults in each of the intervention and the control arms. The intervention arm will involve the delivery of a blended learning education program on lifestyle changes for the management of high blood pressure. The education program comprises evidence-based information with pictures, fact sheets, and published literature about the effects of high blood pressure on CVD development, increased physical activity, and the role of a healthy diet in blood pressure management. The control group involves providing information booklets and general advice at the baseline data collection point. The primary outcome will be the absolute difference in clinic SBP and DBP. Secondary outcomes include the difference in the percentage of people adopting regular exercise habits, cessation of smoking and reducing sodium chloride intake, health literacy of all participants, and the perceived barriers and enablers to adopt behavior changes by collecting qualitative data. Analyses will include analysis of covariance to report the mean difference in blood pressure between the control and the intervention group and the difference in change in blood pressure due to the intervention. Discussion The study will assess the effects of physical activity and lifestyle modification in controlling high blood pressure. This study will develop new evidence as to whether a simple lifestyle program implemented in a rural region of a low- and middle-income country will improve blood pressure parameters for people with different chronic diseases by engaging community people. Trial registration ClinicalTrials.gov NCT04505150 . Registered on 7 August 202