Antimicrobial Products Research Articles

Milk residue depletion of two dry-cow intramammary antimicrobials in dairy goats

There are currently no intramammary antimicrobial products labeled for use in goats in the United States. However, both clin­ical and subclinical mastitis impart heavy production losses to this growing sector of American agriculture annually. Subclini­cal mastitis can be particularly insidious by causing unreal­ized production losses and dry off is an ideal time to detect and manage cases using long-acting intramammary antimicrobial therapy. The goal of this study was to determine milk residue depletion times for 2 such antimicrobials in dairy goats in the immediate post-fresh period.

Functionalization of silver nanoparticles coating cotton fabrics through hydrothermal synthesis for improved antimicrobial properties

Deposition of silver nanoparticles (AgNPs) on the surfaces of cotton fabric (CF) is an approach for producing antimicrobial textile products. CF-AgNPs composites were fabricated ex situ using a simple hydrothermal synthesis of AgNPs, while the fabric was surface modified using a plasma to improve adhesion prior to coating. The morphology and chemical composition of CF-AgNPs nanocomposites were examined using UV–vis spectrophotometry (UV–vis), x-ray diffraction (XRD), transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM). Study results show uniform deposition of AgNPs on cotton fabrics. The CF-AgNPs composite material exhibits excellent laundering durability and antimicrobial performance against Gram-positive, Staphylococcus aureus and Gram-negative, Escherichia coli pathogens. These findings indicate that the developed fabric can be used in a wide range of biomedical applications, health care and various packaging systems.

Optimized production of antimicrobial compounds by endophytic Aspergillus niger CBMAI 2766

Fungi can adapt their metabolism to different cultivation conditions, which may accompany changes in secondary metabolites, but few cost-effective approaches were presented. Therefore, Aspergillus niger CBMAI 2766 was studied aiming at the obtention of antibacterial compounds using KBr, an innocuous and inexpensive salt. The addition of this salt to culture medium was an interesting strategy for obtention of natural products at higher concentrations, as observed by the increased extract mass that favored the isolation of biologically active compounds. Furthermore, an experimental design with temperature, pH, and KBr concentration was performed to maximize the obtained products. Seven compounds were isolated: the phenylalanine derivatives Aspernigrin A 1 and Pestalamide B 2, the polyketides RF-3192C 3, Foncesinone A 6 and Aurasperone A 7, and the bicoumarins Orlandin 4 and Kotanin 5. The bactericidal activity of 5 against Gram-positive bacteria was observed for the first time in this study. Furthermore, antimicrobial activities of the isolated metabolites 3–7 were described in the literature. In summary, the employed experimental design showed that 34 °C and 10 g.L−1 KBr were optimal conditions for producing the bioactive compounds 5-7, employing this inexpensive salt as medium modifier. Thus, indicating that this proposal presents potential for enhancing antimicrobials production.

Antimicrobial resistance and ESBL production in uropathogenic Escherichia coli: a systematic review and meta-analysis in Ethiopia.

Antimicrobial resistance (AMR) is a serious threat to global health systems. Escherichia coli is a major cause of urinary tract infections (UTIs). Understanding the AMR patterns of uropathogenic E. coli (UPEC) is crucial for effective public health interventions worldwide. This systematic review and meta-analysis aimed to consolidate existing research and provide a comprehensive information on AMR UPEC in Ethiopia. We systematically searched databases such as PubMed, Web of Science, and Science Direct, along with including articles from Google Scholar. Data were extracted into Microsoft Excel and analysed using STATA 17.0. Cohen's kappa was computed to assess reviewer agreement, while the I2 statistic evaluated heterogeneity. Egger's tests were conducted to detect publication bias, and random-effects models were utilized to estimate the pooled resistance, with AMR rates for each antibiotic pooled separately. UPEC showed resistance rates, ranging from 3.64% (95% CI: -4.38% to 11.67%) for amikacin to 85.32% (95% CI: 78.6%-92.04%) for ampicillin. Highest resistance was to ampicillin (85.32%), followed by amoxicillin at 82.52% (95% CI: 74.3%-90.74%), tetracycline at 60.67% (95% CI: 51.53%-69.81%) and trimethoprim/sulfamethoxazole at 57.17% (95% CI: 49.93%-64.42%). Conversely, resistance rates were lower for amikacin at 3.64% and meropenem at 5.26% (95% CI: 2.64%-7.88%). UPEC demonstrated a pooled MDR rate of 79.17% (95% CI: 70.32%-88.01%) and a pooled ESBL production rate of 29.16% (95% CI: 22.36%-38.55%). High levels of AMR were observed in UPEC strains, highlighting a critical public health issue requiring urgent action through robust antimicrobial stewardship and surveillance to preserve effective UTI treatment options.

An injectable chitosan-based hydrogel incorporating carbon dots with dual enzyme-mimic activities for synergistically treatment of bacteria infected wounds

Bacterial infections pose a serious threat to human health, and the emergence of superbugs and the growing antibiotic resistance phenomenon have made the development of novel antimicrobial products. In this paper, an ultrasmall Cu, N co-doped carbon dots (CDs-Cu-N) with excellent peroxidase mimic activity and enhanced catalase mimic activity was successfully prepared and anchored to an injectable chitosan (CS)-based hybrid hydrogel. As expected, the CDs-Cu-N-H2O2-CS hybrid hydrogel maintains the excellent enzyme-mimicking properties of CDs-Cu-N and shows superior antibacterial property, which has been proven to effectively promote the healing of S. aureus-infected wounds with good biocompatibility. Benefitting from the dual-enzyme-mimic activity of CDs-Cu-N, the hybrid hydrogel not only can catalyze the generation of highly toxic ROS from low concentration of H2O2 to inhibit the bacterial infections, but also can significantly promote the wound tissue repair and regeneration by improving the anoxic microenvironment and promoting neovascularization. In addition, this hybrid hydrogel also possessed excellent injectability and moldability. It can adapt to various the irregular shapes of acute wounds, maintaining a moist and safe microenvironment while prolonging the action time of nanozyme on wounds, thus promoting wound healing. This injectable hybrid hydrogel shows great potential applications in the field of wound infection management.

Antimicrobial and Phytohormone production potential of Azotobacter chroococcum and its effect on the growth of non-leguminous plants

The overuse of chemical fertilizers in agriculture leads to a decrease in the fertility of soil and increases chemical pollution, which has adverse effects on living things. Biofertilizers have a solution towards chemical fertilizer to improve soil fertility and crop production. Therefore, the present study was undertaken to isolate different isolates of Azotobacter sp. to identify effective isolates for plant growth promoting activities and biological control. Six Azotobacter sp. were isolated and their plant growth promoting activities were checked. The isolate AC3 produced the highest amount (64 μg/ml) of IAA and produced HCN and 72 μg/ml of ammonia. The isolates AC1 and AC4 lacked the HCN production. Isolate AC3 showed a 26 mm zone of clearance on Pikovaskys agar, solublized the highest 71 μg/ml of inorganic phosphate and had the ability to produce siderophores. The isolate AC3 showed good antimicrobial potential against pathogens. Isolate AC3 was identified as Azotobacter chroococcum on the basis of morphological and biochemical characteristics. The bioactive compound was produced by using Azotobacter chroococcum and purified by column chromatography. Fraction 1 showed good antimicrobial activity against all the pathogens. The highest zone of inhibition was 15 mm against F. oxysporum. FT-IR analysis of fraction 1 revealed carboxylic acid, alkane and carbonyl functional groups. Azotobacter chroococcum had a greater effect on the growth of non-leguminous plants in the bacterially inoculated pot than in the control.

Molecular Mechanisms and Cytopathology of Phytophthora: Strategies, Interactions and Future Perspectives

Phytophthora is an aggressive plant pathogen, pose substantial threats to global agriculture, leading to extensive crop losses. Controlling Phytophthora diseases remains challenging, with limited effective methods available. Host resistance emerges as a promising strategy, but its sustainability hinges on a profound comprehension of the intricate molecular dynamics governing Phytophthora-plant interactions. These interactions unveil a hemi-biotrophic lifestyle of Phytophthora, transitioning from biotrophic to necrotrophic phases during infection. The infection process involves a series of orchestrated events, including chemotactic attraction, penetration, and sporulation on the host surface. Molecular cytology elucidates a sophisticated interplay between Phytophthora and plant defense mechanisms. Phytophthora elicits defense responses in host plants through the release of elicitor molecules, triggering PAMP Triggered Immunity (PTI) responses such as antimicrobial compound production and cell wall fortification. Detection and recognition of Phytophthora effectors instigate a second layer of defense in resistant plants, leading to Effector Triggered Immunity (ETI) and hypersensitive response. In response, virulent strains evolve altered effectors to evade detection and suppress host defenses, underscoring the ongoing molecular coevolution between Phytophthora and plants. The pathogenic success of Phytophthora species is attributed to their diverse and rapidly evolving effector gene complements, targeting various host proteins and cellular processes. Future strategies for combating Phytophthora diseases include genome editing using CRISPR/Cas-9 technology to enhance plant immunity and the identification of non-race-specific resistance sources for broad-spectrum protection. In essence, a comprehensive understanding of Phytophthora-plant interactions at the molecular level is imperative for devising effective strategies to mitigate their impact on global agriculture.

Physicochemical and metagenomic analysis of samples from the Roman Baths (Bath, UK) reveals high bacterial and archaeal diversity and a potential for antimicrobial discovery

Antimicrobial resistance of pathogenic bacteria to currently used antibiotics killed an estimated 1.27 million people in 2019 and it is believed that this toll will increase to 10 million per year by 2050. This remains one of the most urgent threats to human health and the hunt for novel antimicrobial natural products (NPs) from microorganisms is essential in efforts to combat this threat, but recent efforts have been unsuccessful. The investigation of extreme ecological niches, such as hot springs, has gained recent interest due to their unique ecosystems, increasing the chance for novel antimicrobial NP discovery. The Roman Baths (Bath) is the UK’s only hot spring and it remains unexplored in terms of microbial diversity. In this study, samples of water, biofilm and sediment were taken from the King’s Spring and the Great Bath, and 16 S rRNA metagenomic sequencing was performed for bacterial and archaeal community exploration. Additionally, samples were used for culture-dependent isolation of antimicrobial NP producing isolates. At the phylum level, data from water samples revealed a shift from an archaeal dominant community in the King’s Spring (Crenarchaeota, Aenigmarchaeota and Nanoarchaeota) to bacteria in the Great Bath (Cyanobacteria and Proteobacteria). Archaea were still present in the biofilm and sediment of the hot spring but consistently the bacterial phyla Cyanobacteria, Bacteroidota, Proteobacteria and Nitrospirota were dominant at both sites. The antimicrobial NP producing candidate phyla Actinobacteria and Myxococcota were found in all samples. From initial isolation experiments, 297 isolates were purified, of which 15 showed broad spectrum activity against human pathogens, though interestingly these were not from target genera in the Actinobacteria. From these data, there is clear potential for novel NP discovery from the Roman Baths, as has been demonstrated from other thermal hot springs globally.

Cultivating Health: a Comprehensive Study on Antimicrobial Activity and Phytochemical Composition of Coriander (Coriandrum Sativum) Seeds

The increasing rate of multi drug resistant pathogens and emergence of non-native pathogens, a quest for novel bioactive compounds has gained extensive attention. Plants have always been serving us as a potential source of bioactive metabolites further resulting in antimicrobial production which is of great use. Coriandrum sativum, commonly known as Coriander or Cilantro, has been celebrated for its culinary uses, adding a burst of flavor and flavor and aroma to dishes worldwide. Beyond its gastronomic delights, this herbaceous plant holds gem within its seeds- a treasure trove of antimicrobial compounds. Coriandrum sativum is one of those valuable plants that contain essential components known as ‘phytochemicals’ and microbe inhibiting property known as ‘antimicrobial property’. The present work is done to test whether Coriandrum sativum contains the phytochemicals and antimicrobial property or not. People consume it as remedy for various diseases like diarrhea, acidity, cholesterol, diabetes, UTI and many more. The phytochemical analysis of the seeds the plant was carried out and it was revealed that they produce essential phytochemicals like tannin, flavonoid, saponin, phenol, steroid, carbohydrate etc. Chemicals like chloroform, Fehling’s solution, H2SO4, HCl etc. were used for the phytochemical tests. The antimicrobial activity of the plant against gram positive and gram-negative bacterial species E. coli were also observed. To test the antimicrobial property, two different solvents Methanol and Petroleum ether were added to seed extract of the plant. Well diffusion method was used for this. After the analysis, positive result was observed which was indicated by a zone of inhibition.

Systemic Impact of Subgingival Infection Control in Periodontitis Patients with Cardiovascular Disease: A Narrative Review.

Periodontitis, an infectious inflammatory condition, is a key contributor to sustained systemic inflammation, intricately linked to atherosclerotic cardiovascular disease (CVD), the leading cause of death in developed nations. Treating periodontitis with subgingival mechanical instrumentation with or without adjunctive antimicrobials reduces the microbial burden and local inflammation, while also potentially bringing systemic benefits for patients with both periodontitis and CVD. This review examines systemic effects of subgingival instrumentation with or without antimicrobial products in individuals with periodontitis and CVD, and explores intricate pathogenetic interactions between periodontitis and CVD. English-language databases (PubMed MEDLINE and Cochrane Library) were searched for studies assessing the effects of nonsurgical periodontal therapies in periodontitis patients with or without CVD. While the ability of periodontal therapy to reduce mortality- and morbidity-related outcomes in CVD patients with periodontitis remains uncertain, some studies indicate a decrease in inflammatory markers and blood cell counts. Subgingival mechanical instrumentation delivered over multiple short sessions carries lower risks of adverse effects, particularly systemic inflammation, compared to the full-mouth delivery, making it a preferable option for CVD patients. Subgingival mechanical instrumentation, ideally conducted in a quadrant-based therapeutic approach, to decontaminate periodontal pockets has the potential to reduce both local and systemic inflammation with minimal adverse effects in patients suffering from periodontitis and concurrent CVD.

Transcriptome analysis reveals the inhibitory mechanism of 3,4-Dimethoxyphenol from Streptomyces albidoflavus strain ML27 against Xanthomonas oryzae pv. oryzae

Bacterial leaf blight, caused by Xanthomonas oryzae pv. oryzae (Xoo), poses a significant threat to rice cultivation across diverse regions. Growing concerns about pesticide resistance and environmental impact underscore the urgent necessity for eco-friendly biopesticides. Here, the complete genome sequence of Streptomyces albidoflavus strain ML27 revealed substantial antimicrobial activity and secondary metabolite production potential through genome mining. 3,4-dimethoxyphenol (purity 97%) was successfully isolated from the fermentation broth of S. albidoflavus strain ML27, exhibiting broad and pronounced inhibitory effects on the growth of seven different fungi and five tested bacteria. The efficacy of 3,4-dimethoxyphenol in controlling rice bacterial leaf blight was evaluated through pot tests, demonstrating substantial therapeutic (69.39%) and protective (84.53%) effects. Application of 3,4-dimethoxyphenol to Xoo resulted in cells displayed notable surface depressions, wrinkles, distortions, or even ruptures compared to their typical morphology. Transcriptome analysis revealed significant inhibition of membrane structures, protein synthesis and secretion, bacterial secretion system, two-component system, flagellar assembly, as well as various metabolic and biosynthetic pathways by 3,4-dimethoxyphenol. Notably, the down-regulation of the type III secretion system (T3SS) expression was a pivotal finding. Furthermore, validation via quantitative real-time polymerase chain reaction (qRT-PCR) analysis confirmed significant downregulation of 10 genes related to T3SS upon 3,4-dimethoxyphenol treatment. Based on these results, it is promising to develop 3,4-dimethoxyphenol as a novel biopesticide targeting the T3SS of Xoo for controlling bacterial leaf blight in rice.

Green synthesis of gold nanoparticles via Moringa oleifera seed extract: antioxidant, antibacterial and anticarcinogenic activity on lung cancer

Plant-mediated biosynthesis of nanoparticles is a green method that allows synthesis in one-pot process. Synthesis of gold nanoparticles with plant extracts has gained interest in the field of biomedicine due to its variety of applications. This study presents the synthesis via green chemistry of gold nanoparticles (AuNPs) using the methanol extract of Moringa oleifera seeds. The AuNPs were synthesized at room temperature. UV–Vis spectroscopy confirmed the formation of AuNPs by identifying the surface plasmon resonance located at 546 nm. TEM analysis shows spherical nanoparticles. FTIR analysis demonstrated the presence of specific bioactive molecules responsible for the Au3+ ion reduction process. The antioxidant activity of the nanoparticles was evaluated on the stabilization of the DPPH radical (1,1-diphenyl-2-picrylhydrazyl, 2,2-diphenyl-1-(2,4,6-trinitrophenyl) hydrazyl). The antimicrobial activity analysis was developed by broth microdilution method at different concentrations against Escherichia coli and Staphylococcus aureus. Minimum inhibitory concentration were 400 µg/mL and 200 µg/mL, respectively. A549 lung cancer cell proliferation was measured according to the MTT protocol, indicating a dose-dependent response and a IC50 of 163.9 ± 13.27 µg/mL. The AuNPs synthesized using M. oleifera seeds showed promise as active materials for antimicrobial or anticancer products.

Natural Sources of Therapeutic Agents Used in Skin Conditions.

Skin conditions are numerous and often have a major impact on patients' quality of life, and effective and safe treatment is very important. The conventional drugs used for skin diseases are usually corticosteroids and antimicrobial products that can induce various side effects, especially with long-term use, which is why researchers are studying alternatives, especially biologically active natural products. Three products caught our attention: bee venom (BV), due to reported experimental results showing anti-inflammatory, antibacterial, antiviral, antioxidant, antimycotic, and anticancer effects, Ficus carica (FC) due to its demonstrated antioxidant, antibacterial, and anti-inflammatory action, and finally Geranium essential oil (GEO), with proven antifungal, antibacterial, anti-inflammatory, and antioxidant effects. Following a review of the literature, we produced this paper, which presents a review of the potential therapeutic applications of the three products in combating various skin conditions and for skin care, because BV, FC, and GEO have common pharmacological actions (anti-inflammatory, antibacterial, and antioxidant). We also focused on studying the safety of the topical use of BV, FC, and GEO, and new approaches to this. This paper presents the use of these natural therapeutic agents to treat patients with conditions such as vitiligo, melasma, and melanoma, as well as their use in treating dermatological conditions in patients with diabetes.

Optimal antimicrobial response to a changing microbial background at a mucus interface

Complex lifeforms host microbiota, microbes that live synergistically with their host. Accordingly, hosts have mechanisms to defend against and tolerate the microbiota. The intestinal mucus, where these systems collide, plays a pivotal role in managing this relationship, yet lacks an integrative theoretical framework. We propose a minimal model to elucidate dynamics at this interface, focusing on the ileum's mucus defense. The model considers the effect of delay in host antimicrobial peptide secretion and how the host can use two different signals, from the bulk microbiota and from segmented filamentous bacteria (SFB), assuming that the SFB anticipate the bulk microbiota. We propose a theory whereby the host can optimize defense by minimizing antimicrobial peptide production and controlling bacterial exposure. Integrating two recent experiments, we show host dynamics are consistent with sensing both bulk and SFB, supporting our “optimal defense” hypothesis. Therefore, we propose that similar mechanisms could prove advantageous to other species and applicable beyond the ileum's mucus barrier. Published by the American Physical Society 2024

Assessing the Feasibility of a Two-Cohort Design to Assess the Potential of Homeopathic Medicinal Products to Reduce Antimicrobial Resistance in Turkeys (The HOMAMR Project)-Study Protocol.

Antimicrobial resistance (AMR) is a serious public health concern worldwide. The European Union requires a reduction in the use of antibiotics by 50% by 2030, with separate regulations on organic production that give preference to homeopathy and phytotherapy in organic farms before the use of conventional medicines (including antibiotics). We have therefore designed a two-phased project whose overarching aim is to investigate the potential role of homeopathic medicinal products (HMPs) in combating AMR in turkeys (the HOMAMR project): a two-cohort feasibility study using turkey-farm data that have been collected and analyzed retrospectively, followed by a prospective two-cohort study in turkey farms that would examine the impact of HMPs on changing antibiotic use. The objective of this paper is to describe the protocol for the first phase of HOMAMR, which is a study under field conditions to assess the feasibility of collecting data retrospectively about turkeys that have been managed conventionally only or with HMPs. Surveys performed on farms in Germany and Austria, including interviews with consenting farmers, will determine the feasibility of comparing retrospectively gathered data on antibiotic use and performance/production data in two cohorts of turkeys: (1) homeopathic treatment with conventional care (antibiotics) added if necessary or (2) conventional care (antibiotics) only. Co-primary outcomes to be studied are the amount of antimicrobial use and production period-related mortality. In addition, other production/performance parameters will be compared between the two treated cohorts. To our knowledge, this is the first feasibility study on the treatment of turkeys using homeopathy, and whose retrospectively obtained data will inform a prospective study that would examine the impact of HMPs on antibiotic use in commercial turkey raising, fattening and breeding production.

Phytochemical characterization, antimicrobial and antioxidant activities of Terminalia catappa methanol and aqueous extracts

BackgroundA study carried out by World Health Organization revealed that around 80% of individuals globally depends on herbal forms of medication with 40% of pharmaceutical products being sourced from medicinal plants. The study objective was to evaluate the phytochemicals composition, in vitro antimicrobial and antioxidant properties of the leaves of Terminalia catappa L. aqueous and methanolic extracts.MethodsAntimicrobial activity was analyzed by disk diffusion, the minimum inhibitory concentration in-vitro assays with ciprofloxacin as the standard for antibacterial assay while nystatin for antifungal assay. Ferric reducing antioxidant power and 2,2-diphenyl-1-picryl-hydrazyl-hydrate assays were used for the evaluation of antioxidant properties of the crude extracts while the groups responsible for this activity identified using Fourier transform infrared spectrophotometer.ResultsThe study found that the leaves of Terminalia catappa contained alkaloids, tannins, steroids, cardiac glycosides, flavonoids, phenols, saponins, and coumarins, but terpenoids were absent. Presence of functional groups associated with this class of compounds such as OH vibrational frequencies were observed in IR spectrum of the crude extracts. Methanolic extract from Terminalia catappa exhibited greater antibacterial properties against Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus, whereas aqueous extract displayed greater antibacterial activity against Bacillus subtilis for all concentrations tested. The amount of the sample that scavenged 50 percent of DPPH (IC50) was found to be 8.723, 13.42 and 13.04 µg/mL for L-ascorbic acid, Terminalia catappa L. methanolic and aqueous extracts respectively. The antimicrobial and antioxidant activities varied with the extract concentration and solvent used in extractions.ConclusionTerminalia catappa L. leaves are prospective for use as a source of therapeutic agents that could lead to the advancement of new antimicrobial and antioxidant products.

Detection and classification of the integrative conjugative elements of Lactococcus lactis

Lactococcus lactis is widely applied by the dairy industry for the fermentation of milk into products such as cheese. Adaptation of L. lactis to the dairy environment often depends on functions encoded by mobile genetic elements (MGEs) such as plasmids. Other L. lactis MGEs that contribute to industrially relevant traits like antimicrobial production and carbohydrate utilization capacities belong to the integrative conjugative elements (ICE). Here we investigate the prevalence of ICEs in L. lactis using an automated search engine that detects colocalized, ICE-associated core-functions (involved in conjugation or mobilization) in lactococcal genomes. This approach enabled the detection of 36 candidate-ICEs in 69 L. lactis genomes. By phylogenetic analysis of conserved protein functions encoded in all lactococcal ICEs, these 36 ICEs could be classified in three main ICE-families that encompass 7 distinguishable ICE-integrases and are characterized by apparent modular-exchangeability and plasticity. Finally, we demonstrate that phylogenetic analysis of the conjugation-associated VirB4 ATPase function differentiates ICE- and plasmid-derived conjugation systems, indicating that conjugal transfer of lactococcal ICEs and plasmids involves genetically distinct machineries. Our genomic analysis and sequence-based classification of lactococcal ICEs creates a comprehensive overview of the conserved functional repertoires encoded by this family of MGEs in L. lactis, which can facilitate the future exploitation of the functional traits they encode by ICE mobilization to appropriate starter culture strains.

Screening Plant Growth-Promoting Bacteria with Antimicrobial Properties for Upland Rice.

This study explores beneficial bacteria isolated from the roots and rhizosphere soil of Khao Rai Leum Pua Phetchabun rice plants. A total of 315 bacterial isolates (KK001 to KK315) were obtained. Plant growth-promoting traits (phosphate solubilization and indole-3-acetic acid (IAA) production), and antimicrobial activity against three rice pathogens (Curvularia lunata NUF001, Bipolaris oryzae 2464, and Xanthomonas oryzae pv. oryzae) were assessed. KK074 was the most prolific in IAA production, generating 362.6 ± 28.0 μg/ml, and KK007 excelled in tricalcium phosphate solubilization, achieving 714.2 ± 12.1 μg/ml. In antimicrobial assays using the dual culture method, KK024 and KK281 exhibited strong inhibitory activity against C. lunata, and KK269 was particularly effective against B. oryzae. In the evaluation of antimicrobial metabolite production, KK281 and KK288 exhibited strong antifungal activities in cell-free supernatants. Given the superior performance of KK281, taxonomically identified as Bacillus sp. KK281, it was investigated further. Lipopeptide extracts from KK281 had significant antimicrobial activity against C. lunata and a minimum inhibitory concentration (MIC) of 3.1 mg/ml against X. oryzae pv. oryzae. LC-ESI-MS/MS analysis revealed the presence of surfactin in the lipopeptide extract. The crude extract was non-cytotoxic to the L-929 cell line at tested concentrations. In conclusion, the in vitro plant growth-promoting and disease-controlling attributes of Bacillus sp. KK281 make it a strong candidate for field evaluation to boost plant growth and manage disease in upland rice.

Seaweeds as a Potential Source of Bioactive Compounds

Seaweeds or marine macroalgae are the oldest members of the plant kingdom, with a history extending back many hundreds of millions of years. Based on photosynthetic pigments, marine macroalgae can be classified into three groups, namely green algae commonly known as Chlorophyta, brown algae or Phaeophyta, and red algae also called Rhodophyta. In response to different kinds of environmental stress, marine algae develop defense strategies resulting in a significant level of structural chemical diversity, from different metabolic pathways. In this review a brief description of the most important seaweed compounds and their bioactivities are presented in this study. Seaweeds contain minerals, amino acids, proteins, fatty acids, lipids, polysaccharides, dietary fibers, vitamins, and various secondary metabolites, such as phenols, alkaloids, terpenes, and pigments. Many of these constituents possess high economic values and can be extracted to obtain antioxidative, anti-inflammatory, anticancer, antimicrobial, antifungal, antiviral, anti-obesity, antidiabetic, and antihypertensive products. Therefore, a new trend to isolate and identify bioactive compounds and constituents from marine algae has emerged.

Impact of Interfering Substances on the Bactericidal Efficacy of Different Commercially Available Hypochlorous Acid-Based Wound Irrigation Solutions Commonly Found in South-East Asia.

The high prevalence of chronic wounds is a growing concern. Recently, hypochlorous acid (HOCl)-based solutions were introduced as an alternative antimicrobial for wound cleansing. In this study, we assessed the in vitro bactericidal activities of seven commercially available wound irrigation products commonly found in South-East Asia. The evaluation was conducted using quantitative suspension method, EN 13727 in either low or high protein conditions. Under low protein conditions, four out of the five HOCl products achieved bactericidal activity (≥5 log10 reduction factor; RF) within 2-5 min, and only one product achieved 5 log10 RF at 15 s. None of the HOCl achieved 5 log10 RF under high protein, even after 30 min of exposure time. In contrast, protein interference on the antimicrobial activities of polyhexamethylene biguanide-based product is less pronounced (low protein: 60 s vs. high protein: 2 min to attain ≥5 log10 RF). Octenidine dihydrochloride is the only active not affected by protein interference achieving ≥5 log10 RF within 15 s in both low and high protein conditions. These findings warrant the need to screen antimicrobial wound care products, especially HOCl-based products, in high protein condition to better reflect the antimicrobial activities in wound care.