Strain Profiles Research Articles

THE RECOMBINANT BACTERIA LACTOCOCCUS LACTIS EXPRESSING SARS-COV-2 SPIKE PROTEIN OR ITS RECEPTOR-BINDING DOMAIN ELICITS AN IMMUNE RESPONSE FOLLOWING ORAL IMMUNISATION OF RATS

Mucosal delivery of antigens represents an effective strategy for the development of vaccines to control diseases with the upper respiratory and/or gastrointestinal tracts as the main routes of transmission. Lactic acid bacteria (LAB) are food-grade bacteria used for the expression of target antigens in the development of mucosal vaccines. Over the last two decades, research on the use of LAB has focused on the construction of genetically modified strains. Current study aimed to develop and examine the recombinant Lactococcus lactis strains, expressing SARS-CoV-2 spike (S) protein or the receptor-binding domain (RBD) of S protein as immunizing antigens.The spike gene from the component II of Sputnik V vaccine and two synthesized coding sequences of the RBD region of SARS-CoV-2 spike protein (319–529 residues named HA-spike and 318–590 residues named mini-spike) were subcloned into expression vector pNZ8121. The resulting plasmids were verified by sequencing and subsequently transformed into competent L. lactis NZ3900 cells. The expression of recombinant proteins in obtained strains was analyzed by western blot using SARS-COV-2 Spike RBD antibodies. The results showed that the spike gene could be efficiently expressed in the cells of recombinant L. lactis. The major 150 kDa band detected in the cell lysate of L. lactis pNZ::spike represented the full-length S protein. Protein bands of 35 kDa and 23 kDa from the lysates of L. lactis pNZ::mini-spike and L. lactis pNZ::HA-spike respectively were detected indicating that the recombinant RBD protein was also successfully expressed. The mini-spike was expressed more abundantly than the HA-spike variant. Based on the growth kinetics and protein expression profiles of recombinant strains, the highest protein yield was obtained under the following conditions: overnight culture was inoculated (1/25 inoculum) and grown until reaching an optical density of 0,9 at 600 nm, then gene expression was induced by adding nisin (1 ng/ml), cells were harvested after 3 h incubation with the inducer. To examine the immunogenicity of recombinant strains, 1 ml of cell suspension (1,5×109 CFU) of L. lactis pNZ::spike, pNZ::mini-spike or L. lactis pNZ::HA-spike was orally administered to Wistar rats. The same volume of peptone water was administered to the control group. Serum was collected from the animals at 28 days and IgG level was determined by ELISA for the quantitative determination of IgG antibodies to SARS-CoV-2 (COVID-19) Spike RBD protein in rat serum. As expected, the serum from control animals lacked antibodies to the RBD antigen. The serum of rats immunised once with cell suspension of the recombinant strains showed the following levels of specific IgG: 124,24±12,56 ng/ml in group pNZ::mini-spike, 165,91±59,13 ng/ml in group pNZ::spike, and 213,60±54,08 ng/ml in group pNZ::HA-spike. The highest IgG level (545,56±230,24 ng/ml) was detected in the serum of rats immunized with ultrasound-treated cell suspension of L. lactis pNZ::spike. No adverse effects were observed in vaccinated animals at regular check-ups throughout the study period.The current results have demonstrated that the RBD and full spike protein were successfully expressed in L. lactis. Oral administration of the recombinant L. lactis expressing S protein or RBD to rats appeared to generate the anti-SARS-CoV-2 antibodies in serum, positioning this bacteria as promising basis for creating oral vaccine.

Evaluation of a Rapid Diagnostic Tool to Estimate Geometry Evolution of Multiple Simultaneously Propagating Fractures from Crosswell Fiber-Optic Strain Measurements

Summary Crosswell low-frequency distributed acoustic sensing (LF-DAS) strain rate measurements generate data useful for hydraulic fracture (HF) diagnostics. These data contain information about HF geometry; however, interpreting the data has relied on time-consuming and computationally expensive numerical interpretation methods. This study aims to evaluate the applicability of a rapid diagnostic tool, known as the “zero strain rate location method” (ZSRLM), for characterizing the geometry of multiple fractures propagating simultaneously. Simulations of multiple fracture propagation are conducted using a planar 3D multifracture simulator that incorporates 3D rock deformation, fluid flow in the wellbore, fluid leakoff, and multiscale fracture propagation regimes. A supertimestepping algorithm is used to solve the nonlinear parabolic equations governing fluid-driven fractures. The far-field strain profile induced by multiple propagating fractures along a crosswell fiber-optic cable is computed using the displacement discontinuity method (DMM). Various scenarios are simulated by adjusting key completion parameters, including the number of clusters, cluster spacing, in-situ stress states, and geomechanical properties. The ZSRLM is then applied to the computed strain field to estimate fracture extents and propagation rates. The accuracy of the ZSRLM is assessed by comparing the estimated fracture geometry parameters with the known simulated values. Our observations indicate that the ZSRLM is not effective when two or more fractures approach the observation well at similar times, as it becomes challenging to discern unique strain-rate converging patterns on waterfall plots for each fracture. However, when fracture arrivals at the monitor well are offset, distinct strain rate patterns emerge, enabling the application of the ZSRLM. Errors between simulated and estimated fracture extent propagation rates are quantified. Finally, the ZSRLM is applied to a field case involving multicluster fracture propagation, and the interpretation of the results is discussed in light of these findings. This research demonstrates the applicability of the ZSRLM for diagnosing the velocities and final extents of multiple fractures propagating simultaneously. The method offers a rapid means of characterizing stimulations using crosswell LF-DAS measurements, which can inform decisions regarding completion design, well spacing, and landing zone. The study contributes to the advancement of efficient fracture diagnostics in the industry, reducing the reliance on numerical interpretation methods.

A diverse Fusarium community is responsible for contamination of rice with a variety of Fusarium toxins

Rice plays an important role in the daily diet in China and therefore its quality and safety have been of great concern. However, few systematic studies have investigated Fusarium community and toxins in rice grains. Here, we collected 1381 rice samples from Jiangsu Province in eastern China and found a higher frequency of zearalenone (ZEN), deoxynivalenol (DON), fumonisins (FBs), and beauvericin (BEA). The positive samples were individually contaminated with a minimum of one and a maximum of ten toxins. Fusarium was isolated and identified as the major fungus, which exhibited temporal and geographical distribution. The most prevalent species complexes within this genus were Fusarium incarnatum-equiseti species complex (FIESC), Fusarium fujikuroi species complex (FFSC), and Fusarium sambucinum species complex (FSAMSC). Nevertheless, the amplicon sequence analysis revealed a low relative abundance of Fusarium in the rice panicles, and the fungal community exhibited an irregular change along with the symptom’s emergence. In vitro toxigenic profiles of Fusarium strains showed significant complexity and specificity depending on the type and content. FIESC strains were non-pathogenic to wheat heads and weakly pathogenic to maize ears, respectively, accumulating lower amounts of toxins than F. asiaticum and F. fujikuroi. There was no significant variation in the ability to cause panicle blight in rice among the various species tested. Our study provides detailed information about the contamination of Fusarium toxins and community in rice after harvest. This information is valuable for understanding the relationship between Fusarium and rice and for developing effective control strategies.

Degradation of lubricating molecules in synovial fluid alters chondrocyte sensitivity to shear strain.

Articular joints facilitate motion and transfer loads to underlying bone through a combination of cartilage tissue and synovial fluid, which together generate a low-friction contact surface. Traumatic injury delivered to cartilage and the surrounding joint capsule causes secretion of proinflammatory cytokines by chondrocytes and the synovium, triggering cartilage matrix breakdown and impairing the ability of synovial fluid to lubricate the joint. Once these inflammatory processes become chronic, posttraumatic osteoarthritis (PTOA) development begins. However, the exact mechanism by which negative alterations to synovial fluid leads to PTOA pathogenesis is not fully understood. We hypothesize that removing the lubricating macromolecules from synovial fluid alters the relationship between mechanical loads and subsequent chondrocyte behavior in injured cartilage. To test this hypothesis, we utilized an ex vivo model of PTOA that involves subjecting cartilage explants to a single rapid impact followed by continuous articulation within a lubricating bath of either healthy synovial fluid, phosphate-buffered saline (PBS), synovial fluid treated with hyaluronidase, or synovial fluid treated with trypsin. These treatments degrade the main macromolecules attributed with providing synovial fluid with its lubricating properties; hyaluronic acid and lubricin. Explants were then bisected and fluorescently stained to assess global and depth-dependent cell death, caspase activity, and mitochondrial depolarization. Explants were tested via confocal elastography to determine the local shear strain profile generated in each lubricant. These results show that degrading hyaluronic acid or lubricin in synovial fluid significantly increases middle zone chondrocyte damage and shear strain loading magnitudes, while also altering chondrocyte sensitivity to loading.

Antioxidative and immunity-enhancing effects of heat-killed probiotic Enterococcus faecium KU22001 without toxin or antibiotic resistance

This study evaluated the probiotic properties, safety profile, and antioxidative and immune system-enhancing effects of Enterococcus faecium strains isolated from human infant feces. E. faecium KU22001, E. faecium KU22002, and E. faecium KU22005 exhibited potential probiotic properties; however, to eliminate concerns about toxin production and antibiotic resistance, the E. faecium strains were heat-treated prior to experimental usage. E. faecium KU22001 showed the highest antioxidant activity and lowest reactive oxygen species production among the three strains. The immune system-enhancing effects of heat-killed E. faecium strains were evaluated using a nitric oxide assay. E. faecium KU22001 induced an increase in the mRNA expression of inducible nitric oxide synthase, cyclooxygenase-2, and proinflammatory cytokines, including tumor necrosis factor-α, interleukin-1β, and interleukin-6 in RAW 264.7 cells. Furthermore, E. faecium KU22001 activated the mitogen-activated protein kinase pathway, which was a key regulator of the immune system. These results demonstrate the potential use of E. faecium KU22001 as a multifunctional food material.

Local strain inhomogeneities during electrical triggering of a metal–insulator transition revealed by X-ray microscopy

Electrical triggering of a metal-insulator transition (MIT) often results in the formation of characteristic spatial patterns such as a metallic filament percolating through an insulating matrix or an insulating barrier splitting a conducting matrix. When MIT triggering is driven by electrothermal effects, the temperature of the filament or barrier can be substantially higher than the rest of the material. Using X-ray microdiffraction and dark-field X-ray microscopy, we show that electrothermal MIT triggering leads to the development of an inhomogeneous strain profile across the switching device, even when the material does not undergo a pronounced, discontinuous structural transition coinciding with the MIT. Diffraction measurements further reveal evidence of unique features associated with MIT triggering including lattice distortions, tilting, and twinning, which indicate structural nonuniformity of both low- and high-resistance regions inside the switching device. Such lattice deformations do not occur under equilibrium, zero-voltage conditions, highlighting the qualitative difference between states achieved through increasing temperature and applying voltage in nonlinear electrothermal materials. Electrically induced strain, lattice distortions, and twinning could have important contributions in the MIT triggering process and drive the material into nonequilibrium states, providing an unconventional pathway to explore the phase space in strongly correlated electronic systems.

Democratizing biomedical simulation through automated model discovery and a universal material subroutine

AbstractPersonalized computational simulations have emerged as a vital tool to understand the biomechanical factors of a disease, predict disease progression, and design personalized intervention. Material modeling is critical for realistic biomedical simulations, and poor model selection can have life-threatening consequences for the patient. However, selecting the best model requires a profound domain knowledge and is limited to a few highly specialized experts in the field. Here we explore the feasibility of eliminating user involvement and automate the process of material modeling in finite element analyses. We leverage recent developments in constitutive neural networks, machine learning, and artificial intelligence to discover the best constitutive model from thousands of possible combinations of a few functional building blocks. We integrate all discoverable models into the finite element workflow by creating a universal material subroutine that contains more than 60,000 models, made up of 16 individual terms. We prototype this workflow using biaxial extension tests from healthy human arteries as input and stress and stretch profiles across the human aortic arch as output. Our results suggest that constitutive neural networks can robustly discover various flavors of arterial models from data, feed these models directly into a finite element simulation, and predict stress and strain profiles that compare favorably to the classical Holzapfel model. Replacing dozens of individual material subroutines by a single universal material subroutine—populated directly via automated model discovery—will make finite element simulations more user-friendly, more robust, and less vulnerable to human error. Democratizing finite element simulation by automating model selection could induce a paradigm shift in physics-based modeling, broaden access to simulation technologies, and empower individuals with varying levels of expertise and diverse backgrounds to actively participate in scientific discovery and push the boundaries of biomedical simulation.

Classification of Cannabis Strains Based on their Chemical Fingerprint-A Broad Analysis of Chemovars in the German Market.

Introduction: Cannabis cultivars were usually categorized based on their genetic profile as sativa, indica, or hybrid types. However, these three criteria do not allow sufficient differentiation between the numerous varieties of cannabis strains. Furthermore, this classification is based on morphological and bio-geographical properties of the plants and does not represent the chemical composition of different cultivars. The concentration of cannabinoids and terpenes are crucial for the pharmacological effect, not only because of the known entourage effect, and therefore needs to be considered by categorization. Materials and Methods: A total of 140 medicinal cannabis flowers available on the German market were analyzed regarding their individual terpene profile using GC-MS analysis. Statistical evaluation was performed to investigate correlations and data relations as well as for clustering. Results: Multivariate analysis showed correlations between individual terpenes. However, there was no statistical correlation between terpene profiles and their respective genetic profile. Terpene profiles of sativa, indica, and hybrid strains are quite heterogenous and clearly showed that there is no relation between terpenes and the estimated pharmacological effect. As a result, we suggest a new classification system based on individual terpene profiles to faster a comprehensive understanding of the expected medical effect. Discussion: Considering main terpenes, we established a concept of six clusters with various terpene profiles being attributed to different medicinal applications. We excluded tetrahydrocannabinol (THC) and cannabidiol (CBD) content from clustering as most of the strains were THC dominant and therefore distort the results. Our pattern of strains with similar terpene profiles might refine the existing classes of chemotypes with different THC:CBD content. Conclusion: The categorization of cannabis strains based on their terpene profiles allows a clearer, finer and, above all, more meaningful classification than the existing sativa/indica classification. Due to the entourage effect and the interactions between cannabinoids and terpenes, this group of substances is also given the necessary consideration when selecting the right medicine for the individual. Within the next steps, further studies are needed with the aim of mapping clinical validated effects to our chemovars. If it is possible to correlate therapy of symptoms to specific chemical profiles personalized cannabinoid therapy will be possible.

Intra-Phenotypic and -Genotypic Variations of Beauveria bassiana (Bals.) Vuill. Strains Infecting Aedes aegypti L. Adults.

Beauveria bassiana has potential for Aedes aegypti biological control. However, its efficacy depends on the strain's geographic location, host susceptibility, and virulence. The present study aimed to evaluate the effectiveness of B. bassiana strain BBPTG4 conidia in controlling Ae. aegypti adults and its detection via introns profile on exposed mosquito corpses. Morphologic characteristics among strains were highly similar. Comprehensive testing of these strains demonstrated that BBPT4 exhibited the ideal biological activity for Ae. aegypti control, with a median lethal time (TL50) of 7.5 d compared to ~3 d and ~10 d for BB01 and BB37 strains, respectively. Infected mosquitoes died after GHA and BBPTG4 exposure, and corpses were analyzed for infecting strains detection. Differences among the seven evaluated strains were determined, assessing five different insertion group I intron profiles in BBTG4, BB01, GHA, BB37, and BB02 strains. Mosquitoes infected by BBPTG4 and non-exposed (negative control) intron profiles were obtained. We detected the presence of introns in the BBPTG4 strain, which were not present in non-exposed mosquitoes. In conclusion, B. bassiana strains showed similarities in terms of their cultural and microscopic morphological characteristics and biologicals virulence level, but different intron profiles. BBPTG4 strain-infected Ae. aegypti adult corpses, showing specific amplicons, enabled us to identify B. bassiana at the strain level among infected mosquitoes. However, monitoring and detection of field-infected insects is essential for further verification.

Distributed fiber optic temperature and strain sensing in cementing and water injection: Insights to well integrity monitoring and multisensing optical fiber cable design

In this study, we installed two fiber optic cables with different designs into a new well, a soft-flat cable and a stainless-steel cable, for distributed fiber optic sensing in cementing and water injection. The two fiber cables were cemented behind casing and the soft-flat cable was used for temperature sensing in cementing as well as cement curing period. The high-speed Rayleigh scanning successfully visualized the cement front tracking from the combined effects of temperature and pressure changes by cement pumping. The temperature variations in cement curing reveled the cement volume and have the potential to identify defects in annular cement and formation damage caused by cementing. The water injection test for strain sensing was carried out with increasing injection rate from 100 L/min to 200 L/min. Strain profiles from the two fiber cables suggested that the strain responses reveal alternation of sand and silt, and reservoir heterogeneity. The water injection results showed that the measured strains of the two cables matched fairly well and the stainless-steel cable showed a high strain sensitivity responding to injection pressure (1 με/5 kPa). Comparison of strain measurement results of the two cables provided valuable insights for future strain fiber cable design. Strain sensing results also indicated a high capability to capture small pressure changes in the heterogeneous layers. Thus, our results demonstrate the high potential of using strain sensing for leak detection and well integrity monitoring in fluid injections, particularly for the long-term monitoring at CO2 storage site.

Automatic generation of knee kinematic models from medical imaging

Background and ObjectiveThree-dimensional spatial mechanisms have been used to accurately predict passive knee kinematics, and have shown potential to be used in optimized multibody kinematic models. Such multi-body models are anatomically consistent and can accurately predict passive knee kinematics, but require extensive medical image processing and thus are not widely adopted. This study aimed to automate the generation of kinematic models of tibiofemoral (TFJ) and patellofemoral (PFJ) joints from segmented magnetic resonance imaging (MRI) and compare them against a corresponding manual pipeline. MethodsFrom segmented MRI of eight healthy participants (four females; aged 14.0 ± 2.6 years), geometric parameters (i.e., articular surfaces, ligament attachments) were determined both automatically and manually, and then assembled into TFJ and PFJ kinematic models to predict passive kinematics. The TFJ model was a six-link mechanism with deformable ligamentous constraints, whereas PFJ was a modified hinge. The ligament length changes through TFJ flexion were prescribed to literature strain profile. The geometric parameters were optimized to ensure physiological kinematic predictions through a Multiple Objective Particle Swarm Optimization. ResultsGeometric parameters showed strong agreement between automatic and manual pipelines (median error of 2.8 mm for anatomical landmarks and 1.5 mm for ligament lengths). Predicted TFJ and PFJ kinematics from the two pipelines were not statistically different, except for tibial superior/inferior translation near terminal TFJ extension. The TFJ kinematics predicted from the automatic pipeline had mean errors of 3.6° and 12.4° for adduction/abduction and internal/external rotation, respectively, and <7 mm mean translational error compared to the manual pipeline. Predicted PFJ had <9° mean rotational errors and <6 mm mean translational errors. ConclusionsThe automatic pipeline developed and presented here can predict passive knee kinematics comparable to a manual pipeline, but removes laborious manual processing and provides a systematic approach to model creation.

Skin Conformal Force Myography Based on Laser Induced Graphene Strain Sensors

Myography – the measurement and recording of muscular activity – finds applications across diverse fields, such as biomechanics, clinical neurophysiology or electrodiagnostic medicine, rehabilitation, sports science, and human-machine interaction.1 Non-invasive myography methods include surface EMG (sEMG, where electrodes are placed on the skin to measure electrical signals during muscle actuation) and force myography (FMG). While sEMG is more broadly explored than FMG, it suffers from limited resolution, signal crosstalk, and skin impedance issues.2 sEMG requires proper skin preparation and electrode placement in order to reduce skin impedance and collect accurate data, making it difficult for home use by general public.3 Furthermore, if one is interested in translating the sEMG signal to muscle forces applied or actions done, as most applications are, the signal needs to be of high quality collected at high sampling rates and needs to be heavily processed.4 On the other hand, FMG measures the position or movement of a limb based on changes in stiffness of the corresponding musculotendinous complex against the default state.5 It offers an attractive alternative to sEMG due to direct measurement of force, user-friendly and less sensitivity to skin impedance, reduced cross talk and robustness in dynamic environments, and high compatibility with prosthetics and exoskeletons.6 While there has been significant progress in FMG devices, existing platforms are still bulky and restrictive to the user.5 A highly flexible and skin conformal sensor system is needed to improve the system's wearability and its integration into other components such as prosthetics. To achieve skin conformality in wearable devices, laser induced graphene (LIG) has emerged as a suitable material owing to its ease of fabrication, cost-effective materials, and tunable properties.7 To the best of our knowledge, skin conformal FMG sensors, especially based on LIG have not been explored. In this work, we developed a skin conformal FMG wearable device based on LIG, capable of continuous strain measurement across the circumference of the forearm for gesture recognition. LIG writing parameters are optimized to obtain a 100-micron highly fibrous film enabling easier transfer. After creating LIG on polyimide, it is transferred onto medical grade polyurethane (MPU) to obtain highly skin conformal and stretchable devices. The sensor system consists of an array of nine individual strain sensors, designed to be placed along the circumference of the forearm. Each strain sensor is connected to an integrated wireless readout system which constantly measures their resistance. Different gestures are performed by the user with the sensor system worn on the forearm. Gestures include individual finger flexions, wrist movements, wrist clenches, and forearm pronation/supination. Upon muscle actuation, each sensor experiences a different strain profile depending on its location with respect to the actuated muscle group. The temporal data associated with each action is analyzed to extract features for training a machine learning (ML)-based classifier. Using the ML model, the system can successfully distinguish among various gestures with a high accuracy (> 97%). Further performance improvement can be achieved by increasing the density of sensors and integrating other piezoresistive materials with LIG to enhance the strain sensitivity. Future work also includes integration with other wearable sensors for simultaneous recording of temperature, pH, and metabolites to achieve a multisensory system for improved health monitoring. References 1 D. F. Stegeman, J. H. Blok, H. J. Hermens and K. Roeleveld, Journal of Electromyography and Kinesiology, 2000, 10, 313–326.2 A. Ranavolo, M. Serrao and F. Draicchio, Front Neurol, 2020, 11, 572069.3 M. L. Delva, K. Lajoie, M. Khoshnam and C. Menon, Biomed Eng Online, 2020, 19, 1–18.4 D. Staudenmann, K. Roeleveld, D. F. Stegeman and J. H. van Dieen, Journal of Electromyography and Kinesiology, 2010, 20, 375–387.5 Z. G. Xiao and C. Menon, Sensors 2019, Vol. 19, Page 4557, 2019, 19, 4557.6 A. Radmand, E. Scheme and K. Englehart, 2016, 53, 443–456.7 R. Ye, D. K. James and J. M. Tour, , DOI:10.1021/acs.accounts.8b00084.

Biofilm formation, agr typing and antibiotic resistance pattern in methicillin-resistant Staphylococcus aureus isolated from hospital environments.

Biofilm development significantly enhances the virulence of methicillin-resistant Staphylococcus aureus (MRSA), leading to severe infections and decreased susceptibility to antibiotics, especially in strains associated with hospital environments. This study examined the occurrence of MRSA, their ability to form biofilms, agr typing, and the antibiotic resistance profiles of biofilm-forming MRSA strains isolated from environmental surfaces at Mymensingh Medical College Hospital (MMCH). From 120 swab samples, 86 (71.67%) tested positive for S. aureus. MRSA was identified in 86 isolates using the disk diffusion technique, and by polymerase chain reaction (PCR), 56 (65.1%) isolates were confirmed to carry the mecA gene. The Crystal Violet Microtiter Plate (CVMP) test revealed that 80.35% (45 isolates) were biofilm-forming and 19.6% (11 isolates) were non-biofilm-forming. Out of 45 biofilm producer isolates 37.5% and 42.9% isolates exhibited strong and intermediate biofilm-forming characteristics, respectively. Molecular analysis revealed that 17.78% of MRSA isolates carried at least one gene related to biofilm formation, specifically icaA, icaB, and icaD genes were discovered in 13.33%, 8.89%, 6.67% of the MRSA isolates, respectively. In agr typing, the most prevalent group was agr I (71.11%), followed by group III (17.78%) and group II (11.11%). Group IV was not detected. The distribution of agr gene groups showed a significant difference among biofilm-forming isolates (p < 0.05). In agr group I, 18.75% of isolates carried the icaA gene, 12.5% carried the icaB gene, and 9.37% carried the icaD gene. Biofilm-forming genes were not detected in any of the isolates from agr groups II or III. There are no statistically significant differences between agr groups and the presence of these genes (p > 0.05). Antibiotic resistance varied significantly among agr groups, with agr group I displaying the highest resistance, agr group II, and agr group III exhibiting the least resistance (p < 0.05). Seventy-three (73.3%) of the isolates were multi-drug resistant, with agr group I displaying nineteen MDR patterns. The occurrence of MRSA in hospital environments and their capacity to form biofilm raises concerns for public health. These findings support the importance of further research focused on agr quorum sensing systems as a basis for developing novel antibacterial agents.

Drug resistance and genetic characteristics of one Eimeria tenella isolate from Xiantao, Hubei Province, China.

Chicken coccidiosis causes retarded growth and low production performance in poultry, resulting in huge economic losses to the poultry industry. In order to prevent and control chicken coccidiosis, great efforts have been made to develop new drugs and vaccines, which require pure isolates of Eimeria spp. In this study, we obtained the Eimeira tenella Xiantao isolate by single oocyst isolation technology and compared its genome with the reference genome GCF_000499545.2_ETH001 of the Houghton strain. The results of the comparative genomic analysis indicated that the genome of this isolate contained 46,888 single nucleotide polymorphisms (SNPs). There were 15,107 small insertion and deletion variations (indels), 1693 structural variations (SV), and 3578 copy number variations (CNV). In addition, 64 broilers were used to determine the resistance profile of Xiantao strain. Drug susceptibility testing revealed that this isolate was completely resistant to monensin, diclazuril, halofuginone, sulfachlorpyrazine sodium, and toltrazuril, but sensitive to decoquinate. These data improve our understanding of drug resistance in avian coccidia.

P24 Antimicrobial susceptibility profiles of hypervirulent strains of Clostridioides difficile of pig and human origin

P24 Antimicrobial susceptibility profiles of hypervirulent strains of <i>Clostridioides difficile</i> of pig and human origin

3D regional evaluation of right ventricular myocardial work from cineCT.

Regional myocardial work (MW) is not measured in the right ventricle (RV) due to a lack of high spatial resolution regional strain (RS) estimates throughout the ventricle. We present a cineCT-based approach to evaluate regional RV performance and demonstrate its ability to phenotype three complex populations: end-stage LV failure (HF), chronic thromboembolic pulmonary hypertension (CTEPH), and repaired tetralogy of Fallot (rTOF). 49 patients (19 HF, 11 CTEPH, 19 rTOF) underwent cineCT and right heart catheterization (RHC). RS was estimated from full-cycle ECG-gated cineCT and combined with RHC pressure waveforms to create regional pressure-strain loops; endocardial MW was measured as the loop area. Detailed, 3D mapping of RS and MW enabled spatial visualization of strain and work strength, and phenotyping of patients. HF patients demonstrated more overall impaired strain and work compared to the CTEPH and rTOF cohorts. For example, the HF patients had more akinetic areas (median: 9%) than CTEPH (median: <1%, p=0.02) and rTOF (median: 1%, p<0.01) and performed more low work (median: 69%) than the rTOF cohort (median: 38%, p<0.01). The CTEPH cohort had more impairment in the septal wall; <1% of the free wall and 16% of the septal wall performed negative work. The rTOF cohort demonstrated a wide distribution of strain and work, ranging from hypokinetic to hyperkinetic strain and low to medium-high work. Impaired strain (-0.15≤RS) and negative work were strongly-to-very strongly correlated with RVEF (R=-0.89, p<0.01; R=-0.70, p<0.01 respectively), while impaired work (MW≤5 mmHg) was moderately correlated with RVEF (R=-0.53, p<0.01). Regional RV MW maps can be derived from clinical CT and RHC studies and can provide patient-specific phenotyping of RV function in complex heart disease patients. Evaluating regional variations in right ventricular (RV) performance can be challenging, particularly in patients with significant impairments due to the need for 3D spatial coverage with high spatial resolution. ECG-gated cineCT can fully visualize the RV and be used to quantify regional strain with high spatial resolution. However, strain is influenced by loading conditions. Myocardial work (MW) - measured clinically derived as the ventricular pressure-strain loop area - is considered a more comprehensive metric due to its independence of preload and afterload. In this study, we sought to develop regional RV myocardial work (MW) assessments in 3D with high spatial resolution by combining cineCT-derived regional strain with RV pressure waveforms from right heart catheterization (RHC). We developed our method using data from three clinical cohorts who routinely undergo cineCT and RHC: patients in heart failure, patients with chronic thromboembolic pulmonary hypertension, and adults with repaired tetralogy of Fallot.We demonstrate that regional strain and work provide different perspectives on RV performance. While strain can be used to evaluate apparent function, similar profiles of RV strain can lead to different MW estimates. Specifically, MW integrates apparent strain with measures of afterload, and timing information helps to account for dyssynchrony. As a result, CT-based assessment of RV MW appears to be a useful new metric for the care of patients with dysfunction.

Distribution and Antibiotic Resistance Profiles of MRSA Clinical Strains Across Different Age Groups and Genders: Implications for Targeted Infection Control and Antibiotic Stewardship Programs

Distribution and Antibiotic Resistance Profiles of MRSA Clinical Strains Across Different Age Groups and Genders: Implications for Targeted Infection Control and Antibiotic Stewardship Programs

Molecular typing of reduced susceptibility of Acinetobacter calcoaceticus-baumannii complex to Chlorhexidine in Turkey by pulsed-field gel electrophoresis.

Introduction. The global spread of Acinetobacter spp., particularly the Acinetobacter calcoaceticusbaumannii (ACB) complex, has led to its recognition as a significant pathogen by the World Health Organization (WHO). The increasing resistance of the ACB complex to multiple antibiotics presents a challenge for treatment, necessitating accurate antibiotic susceptibility profiling after isolation.Hypothesis or gap statement. There is limited understanding of the antimicrobial resistance and chlorhexidine, a biocide, susceptibility profiles of ACB complex strains, especially in clinical settings in Turkey.Aim. This study aimed to identify ACB complex strains recovered from various clinical specimens at Hacettepe University Hospitals in Ankara, Turkey, in 2019, and to assess identification, their antibiotic and chlorhexidine susceptibility profiles, and genomic relatedness.Methodology. Eighty-two ACB complex strains were identified using MALDI-TOF MS. Susceptibility testing to 12 antibiotics was conducted using the disc diffusion method, and colistin, chlorhexidine susceptibility was assessed using the broth microdilution technique, following the latest EUCAST and CLSI guidelines. ACB complex members with reduced chlorhexidine sensitivity were further analyzed by pulsed-field gel electrophoresis (PFGE) for bacterial typing.Results. Among the isolates, 1.2% were multidrug-resistant (MDR), 73.2% were extensively drug-resistant (XDR), and 12.2% were pandrug-resistant (PDR). Carbapenem resistance was found in 86.7% of MDR, PDR, and XDR strains. Colistin resistance was observed in 15.8% of isolates, and 18.2% exhibited decreased susceptibility to chlorhexidine. PFGE revealed seven different clones among strains with reduced chlorhexidine sensitivity, indicating vertical transmission within the hospital.Conclusion. This study highlights the reduced susceptibility to chlorhexidine in ACB complex members and provides epidemiological insights into their spread. The findings underscore the importance of screening for antimicrobial resistance and biocide susceptibility profiles to effectively manage healthcare-associated infections.

Assessment by finite element analysis modelling of tissue strains associated with the use of two different nasogastric tube securement devices.

Nasogastric tube use can lead to pressure injury. Some nasogastric tube securement devices (NG-SD) include hard plastic components. In the current study, we assessed the differences in strain profiles for two NG-SD, one with hard segments and one without hard segments, using finite element analysis (FEA) to measure strain and deformation occurring at the nasogastric tube-tissue interface. FEA in silico models of devices were based on device mechanical test data and clinically relevant placements. Peak strain values were determined by modelling different scenarios using Abaqus software whereby the tubing is moved during wear. The modelling showed peak strains ranging from 52% to 434% for the two NG-SD depending on the tubing placement and device type. Peak strain was always higher for the hard plastic device. Tissue strain energy was a minimum of 133.8 mJ for the NG-SD with no hard parts and a maximum of 311.6 mJ for the NG-SD with hard parts. This study provided evidence through in silico modelling that NG-SD without hard components may impart less strain and stress to tissues which may provide an option for tube securement that is less likely to cause medical device-related pressure injury.

In vitro assessment of probiotic potentials of yeast strains isolated from a cereal-based (Ogi)) traditional fermented food

This present research focused on the isolation of yeast strains from fermented African cereal-based food with promising probiotic attributes. Yeast isolates were obtained from a locally produced cereal-based food “Ogi” also known as Akamu. The yeast was evaluated for their stress tolerance (pH, bile, temperature, NaCl, gastric juice), adhesion properties (auto-aggregation, hydrophobicity) and susceptibility to antibiotics. The strains performed well at 37 °C and exhibited strong ability to tolerate acid (pH 3) and bile salt (1.5%) environment with a percentage survival range of 60-82.61% and 62.96-83.67% respectively. Candida tropicalis (A4) gave the highest salt tolerance at 1% (89.29) and 4% (92.86), while Saccharomyces cerevisiae (A2) showed greater ability to survive the stimulated gastrointestinal conditions at 42.86%. The strains exhibited high auto-aggregation (68.8-94.9%) and a good hydrophobicity to chloroform and toluene. Susceptibility profile of the yeast strains to antibacterial antibiotics showed that all the yeasts presented a resistance pattern. These results indicate that C. tropicalis and S. cerevisiae both have the capability to serve as probiotic agents and can be proposed for various applications. Also, fermented cereal-based Ogi with its wide array of health benefits can serve as a carrier for the delivery of probiotics to both animals and humans as food supplements.