Plate Method Research Articles

Molecular and phenotypic characterization of biofilm formation and antimicrobial resistance patterns of uropathogenic staphylococcus haemolyticus isolates in Casablanca, Morocco

This study aimed to establish the correlation between antibiotic resistance and biofilm formation by Staphylococcus haemolyticus and to examine the impact of sub-inhibitory concentrations of antibiotics (sub-MICs) on biofilm formation.Antibiotic susceptibility testing was conducted using the disk diffusion method, and biofilm formation was determined using Congo red agar and microtiter plate methods. Antibiotic resistance and biofilm-associated genes were detected using polymerase chain reaction.The majority of the twenty-one S. haemolyticus isolates were multidrug-resistant, methicillin-resistant (MRSH) and biofilm producers, including 43 % of moderate biofilm producers. A significant correlation was observed between MRSH and MSSH isolates in terms of biofilm production. Vancomycin, gentamicin, and ciprofloxacin at their sub-MICs tended to promote biofilm formation. The eno gene was present in 76.2 % of strains, followed by aap, and atlE.This study revealed a strong correlation between the biofilm-forming ability and antibiotic resistance in S. haemolyticus, which underlines a crucial public health issue.

Agroclimatic zone-wise prevalence of biofilm forming methicillin resistant staphylococcus aureus in West Bengal

The present study envisages the prevalence of biofilm producing, methicillin resistant Staphylococcus aureus, isolated from cattle milk of different agro-climatic zones of an eastern state of India, West Bengal. The milk samples (n=168) were collected from three predominant agro- climatic zones of South Bengal, viz. new alluvial, coastal saline and red laterite. A total of 146 Staphylococcus aureus isolates were recovered, confirmed by biochemical tests and polymerase chain reaction (PCR). Through PCR of mecA gene, it was found that 45 strains were methicillin resistant, encompassing 28.57% new alluvial zone, 30.19% red laterite region and 29.16% coastal saline region. Determination of biofilm formation was done, both phenotypically by microtiter plate method and genotypically by PCR of icaA and icaD genes, specific for biofilm formation in Staphylococcus aureus. Phenotypic study revealed that 14 isolates were strong biofilm producers, 79 were moderate and the 47 were weak biofilm producers. PCR studies also showed that a total of 30 isolates were icaA positive and 25 isolates were icaD positive. Although no significant difference was found in the occurrence of icaA positive isolates, the possession of icaD by the Staphylococcus aureus isolates varied significantly according to different agro-climatic zones.

Development of a Methodology Based on Optical Interferometry for Measuring Fibrinolytic Activity.

Fibrinolytic activity assay is particularly important for the detection, diagnosis, and treatment of cardiovascular disease and the development of fibrinolytic drugs. A novel efficacious strategy for real-time and label-free dynamic detection of fibrinolytic activity based on ordered porous layer interferometry (OPLI) was developed. Fibrin or a mixture of fibrin and plasminogen (Plg) was loaded into the highly ordered silica colloidal crystal (SCC) film scaffold to construct a fibrinolytic response interference layer to measure fibrinolytic activity with different mechanisms of action. Fibrinolytic enzyme-triggered fibrinolysis led to the migration of interference fringes in the interferogram, which could be represented by optical thickness changes (ΔOT) tracked in real time by the OPLI system. The morphology and optical property of the fibrinolytic response interference layer were characterized, and the Plg content in the fibrinolytic response interference layer and experimental parameters of the system were optimized. The method showed adequate sensitivity for the fibrinolytic activity of lumbrokinase and streptokinase, with wide linear ranges of 12-6000 and 10-2000 U/mL, respectively. Compared with the traditional fibrin plate method, it has a lower detection limit and higher linearity. The whole kinetic process of fibrinolysis by these two fibrinolytic drug models was recorded in real time, and the Michaelis constant and apparent kinetic parameters were calculated. Importantly, some other blood proteins were less interfering with this system, and it showed reliability in fibrin activity detection in real whole blood samples. This study established a better and more targeted research method of in vitro fibrinolysis and provided dynamic monitoring data for the analysis of fibrinolytic activity of whole blood.

An In Vitro and In Silico Study of Luteolin-Loaded Zinc Oxide Nanoparticles: Enhancing Bioactivity and Efficacy for Advanced Therapeutic Applications Against Cariogenic Microorganisms.

Introduction Recent studies have explored alternative methods to enhance caries prevention and treatment.Luteolin compound has been noted for its antimicrobial properties, while zinc nanoparticles (Zn NPs) are recognized for their potent antibacterial effects. This study investigates the synthesis, characterization, and antimicrobial efficacy of luteolin-loaded Zn oxide NPs (Luteo-ZnONPs) against cariogenic bacteria. By combining the biofilm-targeting capabilities of luteolin with the antimicrobial properties of Zn NPs, we aim to explore a novel approach for dental caries management. Methods Luteo-ZnONPswere synthesized and characterized using ultraviolet-visible (UV-vis) and Fourier transform infrared (FTIR) spectroscopy, confirming their successful formation and stability. Antimicrobial efficacy was assessed through minimum inhibitory concentration (MIC), demonstrating effectiveness against cariogenic bacteria such asEscherichia coli,Enterococcus faecalis, Pseudomonas aeruginosa, and Streptococcus mutans in different concentrations.The agar well plate method was employed to analyze the growth inhibitory effect of Luteo-ZnONPs (50 and 100µg/ml, respectively). Streptomycin (100µg/ml) was used as apositive control. The results (zone of inhibition (ZOI) in millimeter, mm) were represented as mean± standard deviation.One-way analysis of variance (ANOVA) was employed to detect the significance (p < 0.05) between the groups. Cytotoxicity was analyzed using the3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT)assayagainst MG63 cells, and doxorubicin was used as a positive control.Wilcoxon rank test was used for the statistical method. Gyrase Bwas downloaded from Protein Data Bank (PDB id: 6F86) and docked against luteolin using Autodock software (version 4.2).The binding score was presented as kcal/mol in table format. Results Characterization results showed that UV-vis spectroscopy revealed characteristic peaks, indicating the successful synthesis and stability of Luteo-ZnONPs. FTIRspectroscopy confirmed the presence of functional groups from luteolin compound interacting with the Zn NPs. It showed effective inhibition againstE. coli on 50µg/ml as 12.45 mm as ZOI and increased with concentration (100 µg/ml as 17.13 mm).It showed minimal ZOI onE. faecalis(8.12, 12.21 on 50 and 100µg/ml, respectively). The cytotoxicity of Luteo-ZnONPs was lesser than doxorubicin on MG63 cells with statistical high significance (p < 0.0014). These results showed thatLuteo-ZnONPs had effective antimicrobial nature againstEnterococcusfamily. Thus, gyrase BfromE. coliwas selected for the molecular docking analysis. The catalytic tunnel in gyrase B (E. coli, PDB: 6F86), influenced by Luteo-ZnONPs, indicated potential for novel, broad-spectrum antimicrobials via selective inhibition at conserved active sites. Conclusion The agar well plate and MIC confirmed that Luteo-ZnONPs exhibited potent antibacterial activity, especiallyat higher concentrations compared to streptomycin.One- way ANOVA demonstrated significant differences in antibacterial efficacy between treatments, validating its superior performance.Its strong interaction onin silicolevel showed the targeted mechanism of action. Luteo-ZnONPs showed lesser toxicity than doxorubicin on MG63 cells. These findings underscore the potential of its broad spectrum antimicrobial nature paving the way for its development into innovative, nontoxic therapeutic solutions.

Interactive effects of osmotic, acid, heat, cold, and freezing stresses on the biofilm formation ability of Salmonella serotypes

AbstractFood‐related stresses such as heating and freezing may influence the biofilm formation ability of bacteria. This study aimed to investigate the main and interactive effects of food‐related stresses on the biofilm formation potential of Salmonella strains isolated from meat. Salmonella enteritidis, Salmonella typhi, and Salmonella typhimurium were subjected to osmotic, acid, heat, cold, and freezing stresses. The colorimetric microtiter plate method was used to measure the biofilm formation ability as a response to the stresses. Among the main effects, freezing time had the most significant effect on the biofilm formation responses of three Salmonella serovars. Freezing reduced the biofilm formation ability of Salmonella typhimurium and Salmonella enteritidis but increased that of Salmonella typhi (p &lt; 0.05). Among the interaction effects, the most significant effect on the biofilm formation response of Salmonella typhi was the interaction between pH and heat, which had a negative effect on the biofilm formation response. In contrast, the interaction between osmotic pressure and cold stresses was the most significant interactive effect on the biofilm formation responses of Salmonella enteritidis and Salmonella typhimurium, which had an increasing effect. This study concluded that the food‐related stresses could change the biofilm formation capacity of Salmonella serotypes, and each serotype might show different biofilm formation abilities in response to different stresses.

Quantitative analysis of loxoprofen sodium loaded microspheres comprising pectin and its thiolated conjugates: In-vivo evaluation of their sustained release behavior

Continuous use of oral NSAIDs can damage mucosal membrane, which results in decreased bioavailability and non-compliance with the therapy. But the use of sustained release drug delivery systems might offer a solution. Objective was to synthesize mucoadhesive SR microspheres by using different combinations of pectin (PEC) and its thiolated derivative (T-PEC3100) for improved loxoprofen (LS) permeation. Thiolated pectin (T-PEC) was synthesized by the esterification method using thioglycolic acid. Thiolation was confirmed by thiol group quantification and charring point determination. Further characterization was done by Fourier Transform Infrared spectroscopy (FTIR), and Scanning electron microscopy (SEM). Ex-vivo mucoadhesion study was performed to confirm the improved characteristics. Microspheres (MS) were prepared using different ratios of PEC/T-PEC by solvent evaporation method and their particle size and surface morphology were evaluated. Mucus permeation study was carried out using the trans-well plate method. Sustained release behavior of prepared microspheres was investigated through the edema inhibition method in albino rats. T-PEC3100 was considered the optimum formulation for further evaluation and contained maximum thiol group content. FTIR spectra showed a characteristic peak of –SH and charring point was also changed considerably confirming the successful thiolation of PEC. SEM results showed spherical microspheres in the size range of 2–10 μm. Thiol-rich formulation of MS exhibited more than 80 % release after 12 h and maximum absorbable dose (MAD) was calculated as 400 μg % inhibition of edema in MS treated group was slowly attained initially but the reduction in inflammation was detected even after 24 h as compared to control group. Promising results from In-vivo edema inhibition study suggest the possible use of these thiolated MS in formulating sustained release formulation for arthritis.

Development of a novel PCB electric field sensor with high-resolution

Abstract Electric field sensors with high resolution and high sensitivity have an important engineering application. Developing a compact, cost-effective Electric Field Sensor (EFS) for aerospace applications, this study introduces a novel use of PCB parallel board probes, enhancing affordability and simplicity. A uniquely designed three-stage adaptive signal amplification module quickly adjusts amplification factors, ensuring high sensitivity and resolution even in complex electric field environments. Due to the non-linear response characteristics of the PCB probes in complex electric field environments, the GTEM cells and the high voltage parallel plate method are used to simulate the complex electric field scenarios. In the weak electric field experiment, the proposed EFS achieved a high resolution of 10 mV/m. In the strong electric field experiment, the linearity of fitting between the proposed EFS and commercial NBM-550EFS reached 0.9999. Finally, based on RBFNN, the overall measurement model of EFS achieves the dynamic measurement range of 0-1 kV/m.

Development of curcumin-loaded lipid nanocapsules for drug delivery across mucus

This study aimed to develop and characterize lipid nanocapsules (LNCs) for mucosal delivery. Curcumin loaded–LNCs (CCM–LNCs) were prepared by phase inversion temperature (PIT) method. Particle characteristics, morphology, entrapment efficiency (EE) and loading capacity were determined. Mucopenetration studies were conducted by Transwell® plate and tube methods. CCM solution served as control.Particle size and zeta-potential of the CCM-loaded LNCs were 67.47 ± 0.15 nm and −32.86 ± 2.51 mV. EE and loading capacity of CCM–LNCs was found to be 98.38 ± 0.45 % and 42.24 ± 2.24 %, respectively. No significant change on stability of CCM–LNCs was found after 30 days storage. CCM–LNCs could penetrate mucus 3 times deeper than CCM solution. Moreover, the delivered amount of CCM across mucus layer was 6 folds higher compared with CCM solution. LNCs with negative charge could be used as a promising particulate delivery system for delivering BCS class IV drug such as CCM across mucus.

Response of soil nematode community structure and metabolic footprint to nitrogen addition in alfalfa fields on the Loess Plateau

Nematodes serve as key indicators of soil health in ecological studies. Therefore, the current study examined the community structure and metabolic footprint of soil nematodes in alfalfa fields across varying levels of N supply in the semi-arid Loess Plateau. The findings offer theoretical guidance for the sustainable management of artificial alfalfa grasslands in this region. The research was based on alfalfa fields with different N application rates (0, 50, 100, 150 kg/ha2) as the research object, The shallow plate method was used to separate and extract soil nematodes, identify soil nematode groups, calculate ecological function index and metabolic footprint, and identify indicator species. A total of 6346 nematodes were isolated in this study, belonging to 27 genera and 19 families. Notably, the plant parasitic nematode Helicotylenchus was predominant. As N addition increased, the plant parasitic index (PPI) increased significantly. A N50 application significantly enhanced the soil nematode diversity index (H\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ ext{H}$$\\end{document}) and the free-living index (MI). The findings showcased a noticeable decrease in disturbance within the N50 soil nematode community. This resulted in a mature and stable community structure primarily attributed to the heightened abundance of omnivorous/predatory nematodes. Across various N levels, soil nematode communities underwent significant alterations in the soil food web structure through shifts in their metabolic footprint. Future strategies should focus on refining N management practices and integrating sustainable approaches like crop rotation and pest management. These efforts will contribute to guidelines ensuring artificial alfalfa grasslands lasting health and productivity.

COMPARISON OF LACTIC ACID BACTERIAL ISOLATES FROM VARIATIONS IN TIME FERMENTATION PROCESS OF CEMPEDAK SKIN

Cempedak is a tropical native fruit from Indonesia and can be consumed by fermenting the skin fruit using a salt solution. The results of the fermentation called Mandai. Fermentation will be successful if there is a role of Lactic Acid Bacteria (LAB). Therefore, this study was conducted to determine the content of LAB in Mandai and isolates when fermented at different times. This study was carried out by dilution and the Pour Plate method, identifications such as morphological identification by gram staining and biochemical test by catalase t and TSIA test. Identification of this study was the observation of clear zone around the bacteria grown on MRSA media as a selective medium for LAB plus CaCO3. In this study, 5 samples of Mandai were used with different fermentation times. The results of the LAB isolation study in Mandai showed that the longer the Mandai fermentation was carried out, the more colonies there would be. While the LAB type was only found in sample 5 which was fermented within 20 weeks. The results obtained were following the characteristics of LAB, including gram-positive bacteria in the form of bacilli or cocci, not having catalase enzyme, and being able to ferment carbohydrates.

THERMAL CONDUCTIVITY OF MATERIALS: IMPLICATIONS FOR HEAT MANAGEMENT IN MEDICAL DEVICES

Effective heat management is crucial for the optimal performance and safety of medical devices. This paper explores the role of thermal conductivity in material selection for medical devices, emphasizing its impact on heat dissipation and device reliability. Various materials, including metals, ceramics, and polymers, are analysed to understand their thermal properties and implications for device design. Metals such as copper and aluminium exhibit high thermal conductivity, making them suitable for high-heat applications, while polymers like polycarbonate offer lower thermal conductivity, beneficial for insulation purposes. Experimental methods for measuring thermal conductivity, including the laser flash method, and guarded hot plate method, are discussed to provide accurate data essential for material selection. The paper also addresses common heat management challenges in medical devices, including overheating in implants and imaging systems, and proposes solutions such as advanced cooling systems and material innovations. The findings highlight the importance of aligning material properties with specific device requirements to enhance performance and patient safety. Future research directions include investigating long-term effects of thermal cycling and exploring new materials and cooling technologies.

Effects of neat and silver coated fly ash cenospheres on the properties of styrene-butadiene-styrene block copolymer composites obtained by a solution mixing method

Utilization of industrial by-products to develop novel value-added materials while mitigating their environmental impact is a crucial issue. Fly ash (FA) microparticles are a common component of power plant waste. This work aims to investigate the impact of varying concentrations of neat/silver-coated FA on the morphology and thermal properties of styrene-butadiene-styrene/FA composites. Composite materials based on styrene-butadiene styrene triblock copolymer (SBS) with various volume fractions of as-received and silver-coated FA were prepared using a solution mixing method. Silver-coated cenosphere particles were prepared using an electroless plating method. Scanning electron microscopy and optical microscopy showed that the solution mixing method obtains composite materials characterized by uniform dispersion of filler without large particle aggregates and predominantly unbroken cenospheres. The tensile strength of the composite with 10% of both as-received and silver-coated fly ash remains at the level of the unfilled SBS sample. However, at higher filler concentrations (20% and 30%), a decrease in strength by 27% and 42% respectively is observed, possibly due to the agglomeration of FA, which leads to a poorer interface and dispersion at higher filler weights. Additionally, thermal analysis in an oxygen atmosphere showed that the introduction of both as-received and metallized cenospheres in the same quantity increased the thermal stability of the tested composition. The temperatures at 5% mass loss of SBS/FA composites were on average 70°C higher than those of the original SBS.

Comparison of surface freshwater PFAS sampling methods to evaluate potential for bias due to PFAS enrichment in the surface microlayer.

Per- and polyfluoroalkyl substances (PFAS) accumulate at the air-water interface of the surface microlayer (SML) on marine and freshwater bodies. In order to determine if including the SML when sampling bulk surface water leads to a high bias in measured PFAS concentrations, a pilot study and a full field study were conducted. The pilot study conducted at two sites was aimed at determining the analytical precision and small-scale (~1 m) spatial variability in concentrations of PFAS in bulk water and the SML. The full field study was performed at 11 sites, where three commonly used bulk surface water sampling methods were compared: (1) a peristaltic pump with tubing that excludes the SML, (2) a fully submerged sample bottle that excludes the SML, and (3) a partially submerged sample bottle that allows inclusion of the SML. The SML was sampled using the glass plate method. The samples were analyzed by liquid chromatography tandem mass spectrometry. The pilot study indicated that sampling variation was greater than analytical variation (although Levene's tests indicated that the differences were not statistically significant) and that relatively small differences in the mean concentration among sampling methods could be detected. The full investigation indicated that there was no evidence of high bias of PFAS concentrations in bulk surface water resulting from inclusion of SML using the partially submerged bottle sampling method. Unexpectedly, there was evidence that samples collected using the partially submerged bottle had slightly lower PFAS concentrations, particularly for less hydrophobic PFAS, than bulk water samples that excluded the SML. Additionally, the PFAS enrichment factor in the SML increased with increasing retention time, although the increase was not evident at all sampling sites for all PFAS. Integr Environ Assess Manag 2024;20:2271-2282. © 2024 SETAC.

A new method of magnetic pulse welding of dissimilar metal plates using a uniform pressure electromagnetic actuator based on pre-deformation

The magnetic pulse welding method using a uniform pressure electromagnetic actuator can effectively weld dissimilar metal plates. However, the existing uniform pressure welding method leads to serious thinning of the plate at the chamfer, lack of welding at the center, and bulging of the welded sample, which seriously affects the quality of the welded joint. To solve these problems and improve the quality of welded joints, a new uniform pressure welding method of dissimilar metal plates based on pre-deformation was developed in this work. In this study, using the welding of an AA1060 aluminum plate and an SS304 steel plate with a thickness of 1 mm as an example, it was confirmed through numerical simulation and experimental research that the pre-deformation of the flyer plate controlled the impact angle of the central area of the plate, and it effectively suppressed central non-welding and serious bulge issues. Further, the welding method also reduced the height of the cushion blocks on both sides, thus mitigating aluminum plate thinning at the chamfer, ultimately improving the tensile strength of the joint. Additionally, a microscopic observation showed that the welding interface formed a wavy composite interface, and the connection strength was good. This welding method can also be extended to welding other dissimilar metal plates.

Optimized analysis and reinforcement design model for RC/SCC box-section bridges using developed advanced design framework

In recent years, there has been a significant rise in the construction of reinforced concrete (RC) and steel-concrete composite (SCC) box-section bridges. However, design codes do not provide specific design methods for the RC plates of such bridges where the plates experience both intricate forces and moments. The current design approaches are primarily based on conventional one-dimensional beam element theory, which neglects the complex spatial force characteristics of the structural elements, potentially leading to unsafe design. Therefore, it is imperative to address this issue. To bridge this gap, a comprehensive analysis and reinforcement design procedure named as the developed advanced design framework (DADF) is proposed in this study. The spatial analysis of bridges was performed using a refined numerical model, called the spatial grid model (SGM), to consider the structural spatial effects with limited model scales. Subsequently, the internal force corresponding matrix (IFCM) was implemented through Python scripts to determine the most critical internal force combination for an RC plate element. Additionally, the three-layered sandwich model (T-LSM) was employed with limit analysis to automatically design reinforcement for all elements, serving as a practical tool for design. This research demonstrates that the implementation of the DADF can significantly reduce steel reinforcement in the RC plates of such bridges by up to 48 %, and 23 % in total, showcasing the efficiency of the developed framework. Overall, the findings emphasize that the proposed DADF offers a robust procedure for steel reinforcement design of RC/SCC box-section bridges.

A vision measurement method for ship hull plates based on multi-view stereo and image segmentation

The background denoising of point clouds is challenging for the measurement of ship hull plates. To address this issue, a vision measurement method is proposed by combining an identity cost volume network (ICV-Net) and a segment anything model (SAM). By applying the ship hull plate masks segmented by SAM to the corresponding depth maps inferred by ICV-Net, the background noise can be directly removed at the depth map level. Additionally, an edge extraction optimization algorithm complementary to SAM is proposed to eliminate the thickness-related noise. Moreover, an efficient depth map refinement algorithm is proposed by imposing the smoothness prior of ship hull plate surfaces and multi-view photometric consistency. Sub-pixel accurate depth maps of ship hull plates can be obtained by the depth map refinement. Experimental results suggest that the proposed method can automatically, accurately and efficiently remove the background noise of ship hull plates, which is crucial toward practical application.

Photocatalytic Degradation of Paracetamol and Antibacterial Activity of La-Modified TiO2 Obtained by Non-Hydrolytic Sol–Gel Route

The current study aims to synthesize and analyze both pure and La-doped TiO2, and evaluate the photocatalytic and antibacterial activity of as-prepared samples. Doped and undoped samples were prepared by the non-hydrolytic sol–gel method from titanium(IV) chloride, benzyl alcohol, and lanthanum(III) nitrate followed by thermal treatment. Lanthanum content in synthesized samples was 0.4, 1, and 5 mol%. The resulting nanopowders’ structure and morphology were described using XRD, IR, and UV–Vis analysis. The average particle sizes of pure and doped TiO2 were about 6–15 nm and anatase was found to be a dominant crystalline phase in the samples. It was observed that particle sizes decreased on increasing La content. The photocatalytic activity of the pure and La-doped sol–gel powders was estimated in the decomposition of paracetamol in distilled water using ultraviolet light illumination. Doping with lanthanum ions has been shown to increase the photocatalytic properties on the degradation of paracetamol. Furthermore, the annealed catalysts (pure and La3+ doped) showed increased photocatalytic activity and degradation of the analgesic in comparison with non-annealed materials. In both cases, the highest photocatalytic efficiency is observed at the optimal La3+ (1 mol%) concentration. The antimicrobial activity of 1 mol% La/TiO2 was tested against a reference strain E. coli in the presence of ultraviolet light and in dark conditions. The number of viable bacterial cells was determined by a spread plate method, and kill curves were performed. The results showed that photoactivated 1 mol% La/TiO2 exhibited a strong bactericidal effect, and in concentration, 1 mg/mL efficiently killed bacteria at an initial cell density of about 105 colony forming units in 1 mL within 15 min.

Molecular characterization, antibiotic resistant pattern and biofilm forming potentiality of bacterial community associated with Ompok pabda fish farming in southwestern Bangladesh

Ompok pabda is gaining popularity in the aquaculture industry due to its increasing demand; however research on microbial diversity and antibiotic susceptibility remains limited. The present study was designed to identify the bacterial pathogens commonly found in the pabda farming system with their biofilm forming potential and antibiotic susceptibility. Different bacterial strains were isolated from water, sediments and gut, gill of pabda fish and the isolates were identified based on their morphological traits, biochemical and molecular analysis. Antibiotic susceptibilities, antibiotic resistance gene determination and biofilm formation capabilities were evaluated by disc diffusion method, PCR amplification and Microtiter plate (MTP) assay, respectively. The respective isolates of gill and gut of pabda aquaculture and their environments were: Exiguobacterium spp. (25 %), Enterococcus spp. (20 %), Bacillus spp. (10 %), Acinetobacter spp. (10 %), Enterobacter spp. (10 %), Aeromonas spp. (10 %), Lactococcus spp. (5 %), Klebsiella spp. (5 %) and Kurthia spp. (5 %). Antibiotic resistance frequencies were found to be relatively high, especially for trimethoprim (95 %), sulfafurazole (75 %), ampicillin (60 %), amoxicillin-clavulanic acid (55 %), and cephradine (50 %). 30 % isolates were categorized as DR bacteria followed by 30 % isolates were MDR bacteria and 40 % were classified as XDR bacteria. Moreover, 4 antibiotic resistant genes were detected with sul1 (30 %), dfrA1 (10 %), tetC (40 %), and qnrA (5 %) of isolates. Based on the microtiter plate method, 20 %, 25 %, and 30 % of isolates were found to produce strong, moderate, and weak biofilms, respectively. The findings suggest that biofilm forming bacterial strains found in O. pabda fish farm may be a potential source of numerous antibiotic-resistant bacteria. The study sheds new light on antibiotic resistance genes, which are typically inherited by bacteria and play an important role in developing effective treatments or control strategies.

Multifunctional, efficient, and durable composites of conductive PMIA/Ag membrane

Developing high-efficiency electromagnetic interference (EMI) shielding composite membranes along with additional functionalities to extend the application scenarios is highly desirable for the next generation electronic devices. Here, we report an ultrathin and flexible EMI shielding materials with sensitive Joule heating and outstanding infrared stealth performance was fabricated from poly-m-phenylene isophthalamide (PMIA) and Ag nanoparticles (AgNPs) through an innovation and simplicity method of electrospinning and electroless plating. Profiting from a continuous three-dimensional (3D) conductive network, the final membrane achieves an outstanding EMI shielding effectiveness (SE) of 100.51 dB (in X-band), a remarkable Joule heating properties with a fast thermal response and low driving voltage (<0.5 V), and an outstanding infrared stealth with a low infrared emissivity (0.28). Meanwhile, the prepared composite membrane demonstrates stable EMI SE even after water washing, continuous bending, and heating treatment. This work integrates high-performance fiber PMIA, characterized by high heat resistance, flame retardancy, self-extinguishing properties, and chemical resistance, with functions such as EMI shielding, infrared stealth, and autonomous thermal management. It has great development potential if utilized in specialized combat uniforms under harsh conditions.

Antibiotic resistance and its correlation with biofilm formation and virulence genes in Klebsiella pneumoniae isolated from wounds.

Klebsiella pneumoniae is the most important species of the Klebsiella genus and often causes hospital infections. These bacteria have a high resistance to most of the available drugs, which has caused concern all over the world. In this study, we investigated the antibiotic resistance profile and the ability to produce extended-spectrum beta-lactamase (ESBL) among K. pneumoniae isolates, and then we investigated the relationship between these two factors with biofilm formation and the prevalence of different virulence genes. In this study, 130 isolates of K. pneumoniae isolated from wounds were investigated. The antibiotic resistance of the isolates was evaluated by the disk diffusion method. The microtiter plate method was used to measure biofilm formation. The prevalence of virulence genes was detected by multiplex PCR. Among the examined isolates, 85.3% showed multidrug resistance. 87.6% of the isolates were ESBL-positive. Imipenem, meropenem, and fosfomycin were the most effective drugs. The ability of the isolates to produce biofilm was strong (80%), moderate (12.3%), and weak (7.6%), respectively. fimH, mrKD, entB, and tolC virulence genes were observed in all isolates. High prevalence of antibiotic resistance (especially multidrug resistance), high prevalence of ESBL-producing isolates, the ability of all isolates to biofilm formation, and the presence of fimH, mrKD, entB, and tolC virulence genes in all isolates show the importance of these factors in the pathogenesis of K. pneumoniae isolates in Iraq.