Bacterial Growth Research Articles

Study on the characteristics of Napier grass fibre reinforced porcelain filler particulates poly lactic acid matrix biocomposite

This study investigates the complex properties of a novel biocomposite by a conventional process, which is composed of poly (lactic acid) (PLA) as the matrix, porcelain particles as fillers, and Napier grass fibre as reinforcement. The primary objective was to evaluate the mechanical, crystalline, water absorption, morphological, and antibacterial properties of the biocomposites in relation to the individual components and their synergistic impacts. When 25 g porcelain particles were added to PLA with Napier grass fibre, mechanical tests demonstrated a 25% increase in tensile strength (maximum tensile strength of 39.76 MPa) and a 30% increase in flexural strength (maximum flexural strength of 41.29 MPa). Scanning electron microscopy (SEM) revealed a strong interfacial bond between the fibre and matrix, with porcelain particles serving as bridges to facilitate stress transmission. The biocomposite exhibited reduced water absorption due to the inherent hydrophobic nature of porcelain, which enhances its resistance to bacterial growth. The study demonstrates that combining Napier grass fibre with porcelain filler particles synergistically enhances the properties of PLA, creating a viable biocomposite material suitable for use in packaging, automotive, and sustainable building industries.

In vitro assessment of the effect of magnetic fields on efficacy of biosynthesized selenium nanoparticles by Alborzia kermanshahica

Cyanobacteria represent a rich resource of a wide array of unique bioactive compounds that are proving to be potent sources of anticancer drugs. Selenium nanoparticles (SeNPs) have shown an increasing potential as major therapeutic platforms and led to the production of higher levels of ROS that can present desirable anticancer properties. Chitosan–SeNPs have also presented antitumor properties against hepatic cancer cell lines, especially the Cht-NP (Chitosan–NPs), promoting ROS generation and mitochondria dysfunction. It is proposed that magnetic fields can add new dimensions to nanoparticle applications. Hence, in this study, the biosynthesis of SeNPs using Alborzia kermanshahica and chitosan (CS) as stabilizers has been developed. The SeNPs synthesis was performed at different cyanobacterial cultivation conditions, including control (without magnetic field) and magnetic fields of 30 mT and 60 mT. The SeNPs were characterized by uv-visible spectroscopy, Fourier-transform infrared spectroscopy (FT-IR), Dynamic light scattering (DLS), zeta potential, and TEM. In addition, the antibacterial activity, inhibition of bacterial growth, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC), as well as the antifungal activity and cytotoxicity of SeNPs, were performed. The results of uv-visible spectrometry, DLS, and zeta potential showed that 60 mT had the highest value regarding the adsorption, size, and stabilization in compared to the control. FTIR spectroscopy results showed consistent spectra, but the increased intensity of peaks indicates an increase in bond number after exposure to 30 mT and 60 mT. The results of the antibacterial activity and the inhibition zone diameter of synthesized nanoparticles showed that Staphylococcus aureus was more sensitive to nanoparticles produced under 60 mT. Se-NPs produced by Alborzia kermanshahica cultured under a 60 mT magnetic field exhibit potent antimicrobial and anticancer properties, making them a promising natural agent for use in the pharmaceutical and biomedical industries.

Temporal dynamics of fecal microbiota community succession in broiler chickens, calves, and piglets under aerobic exposure.

Researchers have extensively studied the effect of oxygen on the growth and survival of bacteria. However, the impact of oxygen on bacterial community structure, particularly its ability to select for taxa within the context of a complex microbial community, is still unclear. In a 21-day microcosm experiment, we investigated the effect of aerobic exposure on the fecal community structure and succession pattern in broiler, calf, and piglet feces (n = 10 for each feces type). Bacterial diversity decreased and community structure changed rapidly in the broiler microbiome (P < 0.001), while the fecal community of calves and piglets, which have higher initial diversity, was stable after initial exposure but decreased in diversity after 3 days (P < 0.001). The response to aerobic exposure was host animal specific, but in all three animals, the change in community structure was driven by a decrease in anaerobic species, primarily belonging to Firmicutes and Bacteroidetes (except in broilers where Bacteroidetes increased), along with an increase in aerobic species belonging to Proteobacteria and Actinobacteria. Using random forest regression, we identified microbial features that predict aerobic exposure. In all three animals, host-beneficial Prevotella-related ASVs decreased after exposure, while ASVs belonging to Acinetobacter, Corynbacterium, and Tissierella were increased. The decrease of Prevotella was rapid in broilers but delayed in calves and piglets. Knowing when these pathobionts increase in abundance after aerobic exposure could inform farm sanitation practices and could be important in designing animal experiments that modulate the microbiome.IMPORTANCEThe fecal microbial community is contained within a dynamic ecosystem of interacting microbes that varies in biotic and abiotic components across different animal species. Although oxygen affects bacterial growth, its specific impact on the structure of complex communities, such as those found in feces, and how these effects vary between different animal species are poorly understood. In this study, we demonstrate that the effect of aerobic exposure on the fecal microbiota was host-animal-specific, primarily driven by a decrease in Firmicutes and Bacteroidetes, but accompanied by an increase in Actinobacteria, Proteobacteria, and other pathobionts. Interestingly, we observed that more complex communities from pig and cattle exhibited initial resilience, while a less diverse community from broilers displayed a rapid response to aerobic exposure. Our findings offer insights that can inform farm sanitation practices, as well as experimental design, sample collection, and processing protocols for microbiome studies across various animal species.

Antibacterial activities of Miang extracts against selected pathogens and the potential of the tannin-free extracts in the growth inhibition of Streptococcus mutans.

Bacterial pathogens have remained a major public health concern for several decades. This study investigated the antibacterial activities of Miang extracts (at non-neutral and neutral pH) against Bacillus cereus TISTR 747, Escherichia coli ATCC 22595, Salmonella enterica serovar Typhimurium TISTR 292 and Streptococcus mutans DMST 18777. The potential of Polyvinylpolypyrrolidone (PVPP)-precipitated tannin-free Miang extracts in growth-inhibition of the cariogenic Streptococcus mutans DMST 18777 and its biofilms was also evaluated. The tannin-rich fermented extracts had the best bacterial growth inhibition against S. mutans DMST 18777 with an MIC of 0.29 and 0.72 mg/mL for nonfilamentous fungi (NFP) Miang and filamentous-fungi-processed (FFP) Miang respectively. This observed anti-streptococcal activity still remained after PVPP-mediated precipitation of bioactive tannins especially, in NFP and FFP Miang. Characterization of the PVPP-treated extracts using High performance liquid chromatography quadrupole-time of flight-mass spectrometry (HPLC-QToF-MS) analysis, also offered an insight into probable compound classes responsible for the activities. In addition, Crystal violet-staining also showed better IC50 values for NFP Miang (4.30 ± 0.66 mg/mL) and FFP Miang (12.73 ± 0.11 mg/mL) against S. mutans DMST 18777 biofilms in vitro. Homology modeling and molecular docking analysis using HPLC-MS identified ligands in tannin-free Miang supernatants, was performed against modelled S. mutans DMST 18777 sortase A enzyme. The in silico analysis suggested that the inhibition by NFP and FFP Miang might be attributed to the presence of ellagic acid, flavonoid aglycones, and glycosides. Thus, these Miang extracts could be optimized and explored as natural active pharmaceutical ingredients (NAPIs) for applications in oral hygienic products.

Review of history and mechanisms of action of lactulose (4-O-β-D-Galactopyranosyl-β-D-fructofuranose): present and future applications in food

AbstractLactulose is a synthetic disaccharide composed of galactose and fructose. Literature review of history, legal status and possible food applications of lactulose in functional foods, such as confectionery and beverages. In the colon, lactulose is fermented by the microbiota and acts as a selective modulator of bacterial growth, promoting the growth of Lactobacilli and Bifidobacteria. It generates organic acids, such as short-chain fatty acids and lactic acid, which lower the pH of the colon and act as an osmotic laxative. Lactulose was first used in 1957 as an ingredient in an infant formula. Later it was registered as a prescription drug and banned for food use in many countries. In 2012, lactulose received an EU (European union) health claim “contributes to acceleration of intestinal transit”. It can be used in food and food supplements across all age groups, from infants to the elderly. Lactulose has favourable technological properties, such as sweetness of 48–62% sucrose without an aftertaste, high solubility, low cariogenic potential and stability. Lactulose gummy candy, without added sweeteners, has an overall likability comparable to classic sucrose/glucose-based candy. With more than 60 years of safe use in infant, child, adult and elderly population, lactulose is an ideal ingredient for prebiotic functional food. Its technological properties allow for development of functional candy and beverages almost indistinguishable from those made from sucrose.

Advances in contezolid: novel oxazolidinone antibacterial in Gram-positive treatment.

The principal objective of this project was to review and thoroughly examine the chemical characteristics, pharmacological activity, and quantification methods associated with contezolid. The article was based on published and ongoing preclinical and clinical studies on the application of contezolid. These studies included experiments on the physicochemical properties of contezolid, in vitro antimicrobial research, in vivo antimicrobial research, and clinical trials in various phases. There were no date restrictions on these studies. In June 2021, contezolid was approved for treating complicated skin and soft tissue infections. The structural modification of contezolid has resulted in better efficacy compared to linezolid. It inhibits bacterial growth by preventing the production of the functional 70S initiation complex required to translate bacterial proteins. The current evidence has indicated a substantial decline in myelosuppression and monoamine oxidase inhibition without impairing its antibacterial properties. Contezolid was found to have a more significant safety profile and to be metabolised by flavin monooxygenase 5, reducing the risk of harmful effects due to drug-drug interactions. Adjusting doses is unnecessary for patients with mild to moderate renal or hepatic insufficiency. As an oral oxazolidinone antimicrobial agent, contezolid is effective against multi-drug resistant Gram-positive bacteria. The introduction of contezolid provided a new clinical option.

Bioprotective potential of Latilactobacillus sakei and Latilactobacillus curvatus in smoked chicken legs with modified atmosphere packaging

The effects of inoculation with bioprotective bacteria (Latilactobacillus sakei and Latilactobacillus carvatus) on the bacterial succession, physicochemical properties, volatile organic compound (VOCs), and sensory attributes of smoked chicken legs stored in modified atmosphere packaging (MAP, 60% CO2 and 40% N2) at 4 °C for 28 days were investigated. Compared with the control (without inoculation), inoculation with L. sakei and L. curvatus inhibited the growth of common spoilage bacteria (Serratia proteamaculans, Weissella ceti, and Pseudomonas fragi) in smoked chicken legs stored in MAP. They significantly (P < 0.05) decreased the levels of lipid oxidation and spoilage markers such as ethanol, 1-octen-3-ol, carbon disulfide, cyclooctanol, 2,3-butanediol, and 3-methyl-1-butanol, slowed down the deterioration of the surface skin color and odor, and prolonged the shelf-life of the product. Inoculation with L. sakei and L. curvatus extended the shelf life of smoked chicken legs stored in MAP by 7 and 14 days, respectively.

Impact of diversified cropping systems and fertilization strategies on soil microbial abundance and functional potentials for nitrogen cycling

Diversified cropping systems and fertilization strategies were proposed to enhance the abundance and diversity of the soil microbiome, thereby stabilizing their beneficial services for maintaining soil fertility and supporting plant growth. Here, we assessed across three different long-term field experiments in Europe (Netherlands, Belgium, Northern Germany) whether diversified cropping systems and fertilization strategies also affect their functional gene abundance. Soil DNA was analyzed by quantitative PCR for quantifying bacteria, archaea and fungi as well as functional genes related to nitrogen (N) transformations; including bacterial and archaeal nitrification (amoA-bac,arch), three steps of the denitrification process (nirK, nirS and nosZ-cladeI,II) and N2 assimilation (nifH), respectively. Crop diversification and fertilization strategies generally enhanced soil total carbon (C), N and microbial abundance, but with variation between sites. Overall effects of diversified cropping systems and fertilization strategies on functional genes were much stronger than on the abundance of bacteria, archaea and fungi. The legume-based cropping systems showed great potential not only in stimulating the growth of N-fixing microorganisms but also in boosting downstream functional potentials for N cycling. The sorghum-based intercropping system suppressed soil ammonia oxidizing prokaryotes. N fertilization reduced the abundance of nitrifiers and denitrifiers except for ammonia-oxidizing bacteria, while the application of the synthetic nitrification inhibitor DMPP combined with mineral N reduced growth of both ammonia-oxidizing bacteria and archaea. In conclusion, this study demonstrates a strong impact of diversified agricultural practices on the soil microbiome and their functional potentials mediating N transformations.

Typhus Fever- A Diagnosis Often Missed as A Cause of Fever.

Background: In tropical countries epidemic and endemic typhus are sometimes missdiagnosed as typhoid fever. Typhus infection is emerging in the subcontinent and clinically presents as nonspecific febrile illness. So high index of clinical suspicion is essential and the objective of the study was to detect typhus infection as a cause of febrile illness. Materials &amp;Method: This is a prospective observational study done from January to December 2019. A total 50 patients of different age groups were taken randomly who were suffering from fever for more than 7 days. All relevant investigations including CBC, Dengue serological test, Widal test, urine routine examination and C/S, blood C/S, chest x-ray were done. Patients not responding to conventional antibiotic therapy and having persistent fever were further investigated for typhus fever with Weil-Felix test. Results: Out of 50 patients 35 were male; age range was 2 to 12 years. Mean duration of fever was 10 days. Blood for CBC showed nonspecific findings, Blood culture and urine for c/s were negative for bacterial growth, dengue serological tests were negative, chest x-ray were normal (except 2 patients had pneumonia). Weil-Felix tests were positive in all cases. 12 cases were positive for both Widal test and Weil-Felix test and in 8 cases blood c/s were also positive with Weil-Felix test. Treatment changed to Doxycycline or Azithromycin in cases of typhus fever. Conclusion: Typhus fever should be taken into account in the management of febrile illness who were admitted without a confirmed cause of fever. BANGLADESH J CHILD HEALTH 2022; VOL 46 (2) : 54-57

Heavy metal application of response surface optimized-lipopeptide biosurfactant produced by Pseudomonas aeruginosa strain CGA-02 in low-cost substrate

Cost-effective methods of biosurfactant production with minimal environmental impact are needed as global demand continues to increase. This study evaluated lipopeptide biosurfactant production in a Pseudomonas aeruginosa strain CGA-02 using a low-cost carbon substrate. The structural properties of the biosurfactant and applicability of the biosurfactant in heavy metal removal were evaluated. Response surface methodology (RSM) involving central composite design (CCD) was used to optimize process parameters to maximize biosurfactant production. The study identified sugar cane molasses and sodium nitrate as carbon and nitrogen sources of choice for bacterial growth and biosurfactant production, with a relatively 2.64-fold increase in biosurfactant yield under optimized conditions. Analysis of the biosurfactant measured a surface tension reduction of water from 72.2 ± 0.26 to 30.5 ± 0.2 mN/m at 40 mg/L critical micelle concentration. GC–MS and FTIR analysis revealed structural properties of the lipopeptide biosurfactant, with fatty acid components predominantly 9-octadecenoic acid (oleic acid), n-hexadecanoic acid, cyclotetrasiloxane and trimyristin, and infrared peaks belonging to amine, carboxyl, nitrile, alkanol, ether and carbonyl groups. Capture of heavy metals using the biosurfactant was evaluated in soil microcosms. Removal rates of 80.47, 100, 77.57, 100, and 97.57% were recorded for As, Pb, Hg, Cd and Cr respectively after 12 weeks of incubation. There was no significant difference (p < 0.05) in the removal efficiency of the biosurfactant and an analogous chemical surfactant, sodium dodecyl sulphate. First and second-order kinetic models described heavy metal removal rates by the biosurfactant. We demonstrate the production of a useful biosurfactant using low-cost waste carbon.

Biogeochemical factors regulating photosynthetically dissolved organic carbon produced by phytoplankton in the Taiwan Strait

The distribution and mechanisms of photosynthetically dissolved organic carbon (PDOC) released by marine phytoplankton are frequently neglected and inadequately understood because most studies on carbon sequestration capacity have focused on photosynthetic particulate organic carbon. In this study, percentage extracellular release (PER) and its environmental influencing factors were investigated for 10 cruises in the Taiwan Strait during 2006–2023. The results indicated that the PER increased horizontally from the nearshore to the off-shelf and vertically from the surface to the bottom within the euphotic zone. PER tends to be low in eutrophic waters such as upwellings and estuaries and high in oligotrophic waters. The study revealed that the average contribution of PDOC to total primary productivity (TPP) in the Taiwan Strait could reach 18.2 ± 11.7%, which is similar to the previously estimated global oceanic values. PDOC production satisfied approximately 25% the carbon requirements of heterotropic bacteria (HB). A detailed analysis of the PER combined with model simulations proved that the distribution of the PER in the Taiwan Strait was caused by the joint contribution of irradiance, size-fractionated phytoplankton, and nutrient stoichiometry. Our results contradict the view that the PER is a constant factor that is unaffected by TPP. However, there was a significant negative correlation between the PER and TPP. The PDOC was always lower than the bacterial carbon demand for a broad range of bacterial growth efficiencies, suggesting a weak coupling between phytoplankton exudation and bacterial metabolism. This challenges the idea that there is a well-coupled relationship between bacteria and phytoplankton present on the continental shelf. These findings indicate significant discrepancies in PDOC mechanisms and the quantitative importance of nearshore eutrophic and off-shelf oligotrophic environments. Consequently, it is unwise to use uniform PERs without differentiation under trophic conditions when reevaluating and appraising marine carbon fixation.

Construction of versatile fibroin/nanozyme hybrid microneedles with controllable phototherapeutic sterilization property against periodontitis

Periodontitis is a highly prevalent disease that affects up to 90% of the worldwide population. The highly dynamic oral environment, tissue-teeth “pocket” structure, and antimicrobial resistance pose challenges to periodontitis local treatments, which urgently need to be upgraded with advanced biomaterials and novel therapeutics. Herein, a new treatment strategy for periodontitis is proposed by synergistic nanozyme catalyzed phototherapeutic/chemodynamic sterilization and microneedles (MNs) in situ delivery platform. A biodegradable versatile photothermal microneedles (MN-SF/CuS) patch was constructed by the in situ growth of monodispersed ultrasmall CuS nanozyme on silk-fibroin (SF) biomolecule and then hybridization in methacrylated hyaluronic acid (HAMA). The synthetic SF/CuS nanozyme endows microneedles with amplifies phototherapeutic/chemodynamic sterilization, excellent mechanical properties, and promotes periodontal tissue regeneration. The constructed MN-SF/CuS can be conveniently and minimally invasively inserted deeply into periodontal tissue without being affected by saliva, where it delivers thermal action, reactive oxygen species, and copper to the specified depth, achieving rapid sterilization and inhibition of bacterial growth. Meanwhile, MN-SF/CuS achieves on-demand phototherapy effect without damaging surrounding normal tissues. A preclinical large animal model confirmed that the MN-SF/CuS provided excellent irreversible antibacterial activity and promoted tissue regeneration, substantially improving the tolerance and compliance of periodontal treatment.

Formulating biomolecular crowns on micelles: A potential strategy for improving micelle stability

The complex environment in blood circulation has a tremendous destabilizing effect on the micelles structure, which is a vital issue to be addressed in micelles design and application. Biomolecule crowns, quickly formed on the surface of nanocarriers in vivo, may alter the physicochemical properties of nanocarriers. In this study, bovine serum albumin (BSA) or fetal bovine serum (FBS) was formulated as the biomolecular crown of the bacterial lipase-responsive micelles encapsulating the hydrophobic antibiotics chloramphenicol (CHL) to investigate their stabilization effect on the micelles. Compared with BSA-crowned micelles (BSA/PM@CHL), FBS-crowned micelles (FBS/PM@CHL) reduced drug leakage by more than 90 % without masking their lipase responsiveness, it also inhibited 77 % of bacterial growth in in vitro antibacterial activity study and significantly increased the area under plasma concentration curve and in vivo half-life in pharmacokinetic study. Then the Förster resonance energy transfer (Fret) Effect was used to further explore the mechanisms responsible for the differences between the BSA-crown and FBS-crown. The in vitro anti-dilution tests below the critical micellar concentration showed that FBS-crown could improve the thermodynamic stability of the micelles, the micelle integrity of FBS/PM was 2 times higher than that of PM diluted with aqueous dilution and 6.5 times higher than that diluted with rat plasma dilution. In vivo optical imaging study showed that micelles with dual-labeled FBS/PM (mean value = 0.363) maintained better structural integrity than dual-labeled PM (mean value = 0.325) after 4 h of injection, explaining the ability of FBS-crowned micelles to improve pharmacokinetic parameters in terms of thermodynamic stability. Besides, the destruction of PM integrity slowed down after injection into the blood circulation for 4–8h, indicating that the baring of biomolecular-crown may be in the late cycle. Overall, the biomolecular-crowned micelles strategy presents a promising strategy for maintaining the structural and functional stability of micelles under physiological conditions.

Battling Salmonella enteritidis infections: integrating proteomics and in vivo assessment of Galla Chinensis tannic acid

Salmonella infections pose a significant threat to animal and human health. Phytochemicals present a potential alternative treatment. Galla chinensis tannic acid (GCTA), a hydrolyzable polyphenolic compound, inhibits bacterial growth and demonstrates potential as an alternative or supplement to antibiotics to prevent Salmonella infections. However, little is known about the antimicrobial mechanism of GCTA against Salmonella. Here, we revealed 456 differentially expressed proteins upon GCTA treatment, impacting pathways related to DNA replication, repair, genomic stability, cell wall biogenesis, and lipid metabolism using TMT-labeled proteomic analysis. TEM analysis suggested altered bacterial morphology and structure post-treatment. A Salmonella-infected-mouse model indicated that GCTA administration improved inflammatory markers, alleviated intestinal histopathological alterations, and reduced Salmonella enterica serovar Enteritidis (S. Enteritidis) colonization in the liver and spleen of Salmonella-infected mice. The LD50 of GCTA was 4100 mg/kg with an oral single dose, vastly exceeding the therapeutic dose. Thus, GCTA exhibited antibacterial and anti-infective activity against S. Enteritidis. Our results provided insight into the molecular mechanisms of these antibacterial effects, and highlights the potential of GCTA as an alternative to antibiotics.

Bacterial growth in patients with low back pain and Modic changes: protocol of a multicentre, case–control biopsy study

IntroductionBacterial infection and Modic changes (MCs) as causes of low back pain (LBP) are debated. Results diverged between two randomised controlled trials examining the effect of amoxicillin with and without...

Structural geometry, electronic properties and pre-clinical evaluation of antibacterial compounds from lichen-associated Streptomyces mobaraensis DRM1 and Nocardiopsis synnemataformans DRM2

Antibacterial compounds Phenol, 2,4-bis(1,1-dimethylethyl) and Lupeol obtained from lichen-associated Streptomyces mobaraensis DRM1 and Nocardiopsis synnemataformans DRM2 respectively. The geometry, electronic properties and binding affinities of antibacterial compound Phenol, 2,4-bis(1,1-dimethylethyl) and Lupeol was determined. The in silico molecular mechanics of bacterial growth inhibition by Phenol, 2,4-bis(1,1-dimethylethyl) and Lupeol was established in Pseudomonas aeroginosa and Salmonella typhi by molecular docking, molecular simulation approach. The bacterial growth is inhibited by inactivating the vital enzyme PqsA and actin in bacterial system of Pseudomonas and Salmonella. The antibacterial compound produced by lichen associated actinobiont are adhere to Lipinski rule 5 and established criteria for drug likeness with the acceptable ADME properties and expand our understanding of their pharmacological approach. Further it also revels the adaptation and survival lichen in adverse climatic condition through the antimicrobials in lichen-associated actinobiont.

Topical Vancomycin is More Efficient than Povidone-Iodine Treatment in Controlling Bacterial Growth in Methicillin-Resistant Staphylococcus Aureus Keratitis Model in Rabbits

Purpose: To evaluate the efficacy of topical vancomycin and povidone iodine (PI) application on methicillin-resistant Staphylococcus aureus (MRSA) keratitis model in rabbits. Methods: MRSA keratitis was induced by injecting 0.1 mL MRSA containing 1000 colony-forming units (CFU) into central cornea of right eyes of 24 New Zealand White rabbits. Animals were divided into four groups (n = 6): control (treated with balanced salt solution), 50 mg/mL topical vancomycin, 5% topical PI, and combination; examined before and after treatment, and corneal tissues were harvested for analysis at 9th hour of treatment. Results: Bacterial load was determined as: 7.63 ± 0.82 log10 CFU/g in control group, 6.95 ± 1.66 log10 CFU/g in PI group, 4.67 ± 0.77 log10 CFU/g in combination group, and 4.33 ± 0.71 log10 CFU/g in vancomycin group (p = 0.001). Median of total clinical score increased significantly from 7 [range: 5–8] to 11.5 [range: 11–15] (p = 0.001) in control group, did not change (6 [range: 5–8] to 7 [range: 5–7]; p = 0.695) in vancomycin group, increased significantly from 7 [range: 5–8] to 12.5 [range: 10–14] (p < 0.001) in PI group, increased significantly from 6.5 [range: 5–7] to 8 [range: 7–9] in combination group (p = 0.002). Post-treatment clinical scores for chemosis, conjunctival injection, iritis, hypopyon, epithelial erosion, and corneal infiltrate were significantly lower in vancomycin-treated groups compared to others (p < 0.05). In PI-treated groups, especially scores for chemosis, conjunctival injection, epithelial erosion and corneal infiltrate were significantly higher than vancomycin (p < 0.05). Conclusion: Topical vancomycin significantly inhibited bacterial growth in MRSA keratitis. However, PI was ineffective in controlling this growth; additionally, exerted toxic effect on ocular surface. When vancomycin was combined with PI, no additional increase in efficacy of treatment was detected compared to only vancomycin.

Specific discrimination of pathogenic bacteria causing septic arthritis using Raman spectroscopy: In-vitro study

In this study we performed preliminary experiments using Raman spectroscopy as an evolving technology in biofluid and microbial characterization, to explore its potential for rapid diagnosis of pathogenic bacteria in an in-vitro synovial fluid infection model. Normal human synovial fluids samples were collected from patients undergoing knee surgery and the three most common pathogenic bacteria introduced in-vitro into the samples. The bacterial growth was systematically monitored using a Raman spectroscopy. Multivariate regression analysis of acquired spectra showed bacterial characteristic Raman bands related to bacterial cell membranes and DNA structures to increase continuously as the incubation period was increased. Spectra signature recorded from cultured synovial fluid samples showed a significant loss in synovial quality and protein morphology over time compared to control samples. In this study, Raman spectroscopy shows promise for rapid pathogenic bacteria identification in synovial fluid. Marker peaks distinguished inoculated bacteria, while chemical changes reveal infection dynamics.

Influence of bacterial biomineralization conditions on the microstructural characteristics of cement mortar

Bacterial concrete is considered an effective self-healing material due to its capacity to repair damages such as cracks autonomously throughout microbially induced calcium carbonate precipitation (MICP). This study aimed to evaluate the direct incorporation of bacteria into mortar within the framework of concrete damage repairing technol-ogy. Sporosarcina pasteurii, a bacterium capable of surviving in alkaline conditions and inducing biomineralization by precipitating calcium carbonate, was selected for this purpose. Cement mortars with and without bacteria were prepared, and these samples were cured in different solutions to examine bacterial reactivity: a media solution for bacterial growth and calcium carbonate precipitation, a urea solution for calcium carbonate precipitation, and normal water. Mechanical properties and microstructural characteristics were investigated using various approaches. The out-comes revealed that the calcium carbonate precipitated by bacteria in cement mortar exhibited varying phases, such as calcite and vaterite, depending on the specific curing solutions employed. Particularly, the presence of properly precipitated calcium carbonate was found to significantly enhance the durability and mechanical properties of the cement mortar.

Randomized, crossover trial: comparing the effects of standardized egg-white meal and Vital® on global gastric emptying parameters and intragastric meal distribution in healthy Asian participants.

Measurements of gastric emptying and accommodation for alternative test-meal protocol during gastric emptying scintigraphy (GES), such as high-calorie nutrient drinks, are not fully established. We aimed to compare the effects of standardized egg-white meal (EWM) versus high-calorie nutrient drink (Vital®; Abbott Laboratories) on global GES parameters and intragastric meal distribution at immediate scan (IMD0h). Of 84 screened participants, 60 asymptomatic healthy Asian population (38 females; 24.0±1.5years; 23.8±2.6kg/m2) were recruited in this 2×2 (AB/BA) crossover trial. Participants were randomized to a 4-h GES with 99mTc-radiolabeled EWM (~255.8kcal), followed by a 200mL Vital® (300kcal), or vice versa, separated by a 2-week washout period. Global meal retention (GMR), power-exponential model emptying parameters (half-emptying [T1/2], lag phases [Tlag2%, Tlag5%, Tlag10%]), and IMD0h were determined and compared. GMRs for both test meals were within the international standard references for solid GES. Compared to EWM, Vital® exhibited significantly lower GMRs (faster emptying) from 0.5 to 3h (all P<0.001) but comparable at 4h (P=0.153). Similar observations were found for the model-based T1/2 and the different Tlag thresholds (all P<0.001). Furthermore, IMD0h was found to be lower with Vital®, indicating lower gastric accommodation (faster antral filling) immediately post-ingestion (P<0.001). Both test meals showed significant moderate-to-strong positive associations at the late-phase GE (GMR 2-4h, T1/2) (all P<0.05). Overall, Vital® is an acceptable alternative test meal to the EWM for GES; however, exercise caution when interpreting early-phase GE. The normative values for global GES parameters and IMD0h are also established.