Growth Of Pathogens Research Articles

DETERMINATION OF ANTIBIOSIS OF Trichoderma species AGAINST FUNGI ASSOCIATED WITH CORN (Zea Mays L.) SPOILAGE

Biological control of food spoilage microorganisms is gaining more attention because it is a safe and cheap technique. This study evaluated the antagonistic potential of Trichoderma species against corn spoilage fungi by plate co-culture technique for seven days. Fungal isolates from corn spoilage were examined morphologically and microscopically. The percentage growth inhibition (PGI) of Trichoderma species against the corn spoilage fungi were A. flavus (15%), A. niger (14%), A. terreus (62.9%), Fusarium spp. (5.9%), Nigrospora spp. (61.4%) and Penicillium spp. (62.5%). The result obtained in this study revealed that Trichoderma spp. had significant inhibitory effects against the growth of fungal pathogens associated with corn spoilage. Therefore, it could be explored for control of post-harvest fungal spoilage of corn. It is recommended that in order to compare the antagonistic strength of the Trichoderma species, different species of Trichoderma should be tested against the same spoilage fungi.

Controlling soft rot of green pepper by bacteriocin paracin wx3 and its effect on storage quality of green pepper

A bacteriocin paracin wx3 was investigated as a candidate of natural preservative to control green pepper soft rot. Firstly, paracin wx3 was heterologously expressed in Pichia pastoris X33 with an improved yield of 0.537 g/L. Its size and amino acid sequence were confirmed by Tricine-SDS-PAGE and LC-MS/MS. Then, result of antibacterial activity showed that its MIC value against Pectobacterium carotovorum was 16 μg/mL. In vitro, paracin wx3 completely killed the pathogen at high concentrations ≥8 × MIC. In vivo, disease incidence of green pepper soft rot was decreased from 90% (control) to <2% (8 × MIC). Subsequently, results of action mode showed that paracin wx3 inhibited the growth of pathogen by pore-formation on cell membrane. Last, paracin wx3 treatment reduced losses of weight, firmness, total soluble solid, Vc of green pepper during storage. It also inhibited the production of soft rot volatile p-xylene, 1-butanol, 2-methyl-2-propanol, 3-hydroxybutan-2-one-D, 2-pentyl furan, butanal, etc.

Rapid dissemination of host metabolism–manipulating genes via integrative and conjugative elements

Integrative and conjugative elements (ICEs) are self-transmissible mobile elements that transfer functional genetic units across broad phylogenetic distances. Accessory genes shuttled by ICEs can make significant contributions to bacterial fitness. Most ICEs characterized to date encode readily observable phenotypes contributing to symbiosis, pathogenicity, and antimicrobial resistance, yet the majority of ICEs carry genes of unknown function. Recent observations of rapid acquisition of ICEs in a pandemic lineage of Pseudomonas syringae pv. actinidae led to investigation of the structural and functional diversity of these elements. Fifty-three unique ICE types were identified across the P. syringae species complex. Together they form a distinct family of ICEs (PsICEs) that share a distant relationship to ICEs found in Pseudomonas aeruginosa. PsICEs are defined by conserved backbone genes punctuated by an array of accessory cargo genes, are highly recombinogenic, and display distinct evolutionary histories compared to their bacterial hosts. The most common cargo is a recently disseminated 16-kb mobile genetic element designated Tn6212. Deletion of Tn6212 did not alter pathogen growth in planta, but mutants displayed fitness defects when grown on tricarboxylic acid (TCA) cycle intermediates. RNA-seq analysis of a set of nested deletion mutants showed that a Tn6212-encoded LysR regulator has global effects on chromosomal gene expression. We show that Tn6212 responds to preferred carbon sources and manipulates bacterial metabolism to maximize growth.

Unleashing Bacillus species as versatile antagonists: Harnessing the biocontrol potentials of the plant growth-promoting rhizobacteria to combat Macrophomina phaseolina infection in Gloriosa superba

Charcoal rot caused by Macrophomina phaseolina is one of the most devastating diseases that cause severe yield loss in Gloriosa superba cultivation. Plant growth-promoting rhizobacteria (PGPR) are extensively harnessed as biocontrol agents due to their effectiveness in combating a wide array of plant pathogens through a multifaceted approach. The present study delved into the mechanisms underlying its ability to inhibit root rot pathogen and its capacity to promote plant growth in G. superba, commonly known as glory lily. PGPR isolated from the rhizosphere of glory lily were subjected to in vitro assessments using the dual plate technique. The isolated Bacillus subtilis BGS-10 and B. velezensis BGS-21 showed higher mycelial inhibition (61%) against M. phaseolina. These strains also promote plant growth by producing indole-3-acetic acid, siderophore, ammonia, amylase, cellulase, pectinase, xylanase, and lipase chemicals. Genome screening of BGS-10 and BGS-21 revealed the presence of antimicrobial peptide genes such as Iturin (ituD gene), surfactin (srfA and sfp genes) along with the mycolytic enzyme β-1,3-glucanase. Further, the presence of secondary metabolites in the bacterial secretome was identified through gas chromatography-mass spectrometry (GC/MS) analysis. Notably, pyrrolo[1,2-a] pyrazine-1,4-dione, hexahydro-3-(2-methylpropyl), 9 H-pyrido[3,4-b] indole and L-leucyl-D-leucine exhibited the highest docking score against enzymes responsible for pathogen growth and plant cell wall degradation. Under glasshouse conditions, tuber treatment and soil application of talc-based formulation of B. subtilis BGS-10 and B. velezensis BGS-21 suppress the root rot incidence with a minimal disease incidence of 27.78% over untreated control. Concurrently, there was a notable induction of defense-related enzymes, including peroxidase (PO), polyphenol oxidase (PPO), and phenylalanine ammonia-lyase (PAL), in glory lily. Therefore, it can be concluded that plant growth-promoting Bacillus strains play a significant role in fortifying the plant's defense mechanisms against the root rot pathogen.

A perspective on varied fungal virulence factors causing infection in host plants.

Pathogenic fungi and their spores are ubiquitously present and invade the tissues of higher living plants causing pathogenesis and inevitably death or retarded growth. A group of fungi kills its hosts and consume the dead tissues (necrotrophs), while others feed on living tissue (biotrophs) or combination of two (hemibiotrophs). A number of virulent factors is used by fungal pathogens to inhabit new hosts and cause illness. Fungal pathogens develop specialized structures for complete invasion into plant organs to regulate pathogenic growth. Virulence factors like effectors, mycotoxins, cell wall degrading enzymes and organic acids have varied roles depending on the infection strategy and assist the pathogens to possess control on living tissues of the plants. Infection strategies employed by fungi generally masks the plant defense mechanism, however necrotrophs are best known to harm plant tissues with their poisonous secretion. Interestingly, the effector chemicals released by Biotrophs reduce plant cell growth and regulate plant metabolism in their advantage causing no direct death. All these virulence tools cause huge loss to the agricultural product of pre- harvest crops and post-harvest yields causing low output leading to huge economic losses. This review focusses on comprehensive study of range of virulence factors of the pathogenic fungi responsible for their invasion inside the healthy tissues of plants. The compiled information would influence researchers to design antidote against all virulence factors of fungi relevant to their area of research which could pave way for protection against plant pathogenesis.

Bio-formulated chitosan nanoparticles enhance disease resistance against rice blast by physiomorphic, transcriptional, and microbiome modulation of rice (Oryza sativa L.)

Rice blast disease (RBD) caused by Magnaporthe oryzae, threaten food security by cutting agricultural output. Nano agrochemicals are now perceived as sustainable, cost-effective alternatives to traditional pesticides. This study investigated bioformulation of moringa chitosan nanoparticles (M-CsNPs) and their mechanisms for suppressing RBD while minimizing toxic effects on the microenvironment. M-CsNPs, sized 46 nm with semi-spherical morphology, significantly suppressed pathogen growth, integrity, and colonization at 200 mg L−1in vitro. Greenhouse tests with foliar exposure to the same concentration resulted in a substantial 77.7 % reduction in RBD, enhancing antioxidant enzyme activity and plant health. Furthermore, M-CsNPs improved photosynthesis, gas exchange, and the nutritional profile of diseased rice plants. RNA-seq analysis highlighted upregulated defense-related genes in treated rice plants. Metagenomic study showcased reshaping of the rice microbiome, reducing Magnaporthe abundance by 93.5 %. Both healthy and diseased rice plants showed increased microbial diversity, particularly favoring specific beneficial species Thiobacillus, Nitrospira, Nocardioides, and Sphingomicrobium in the rhizosphere and Azonexus, Agarivorans, and Bradyrhizobium in the phyllosphere. This comprehensive study unravels the diverse mechanisms by which M-CsNPs interact with plants and pathogens, curbing M. oryzae damage, promoting plant growth, and modulating the rice microbiome. It underscores the significant potential for effective plant disease management.

Dynamics of Listeriamonocytogenes and Salmonella enterica on Cooked Vegetables During Storage

Fresh vegetables have been linked to multiple foodborne outbreaks in the U.S., with Listeria monocytogenes and Salmonella enterica identified as leading causes. Beyond raw vegetables, cooked vegetables can also pose food safety concerns due to improper cooking temperature and time combinations or postcooking contamination. Cooked vegetables, having had their native microbiota reduced through heat inactivation, might provide an environment that favors the growth of pathogens due to diminished microbial competition. While the risks associated with raw vegetables are recognized, the survival and growth of pathogens on cooked vegetables remain inadequately studied. This study investigated the growth kinetics of both L. monocytogenes and S. enterica on various cooked vegetables (carrot, corn, onions, green bell pepper, and potato). Vegetables were cooked at 177°C until the internal temperature reached 90°C and then cooled to 5°C. Cooled vegetables were inoculated with a four-strain cocktail of either L. monocytogenes or S. enterica at 3 log CFU/g, then stored at different temperatures (5, 10, or 25°C) for up to 7 days. Both pathogens survived on all vegetables when stored at 5°C. At 10°C, both pathogens proliferated on all vegetables, with the exception of L. monocytogenes on pepper. At 25°C, the highest growth rates were observed by both pathogens on carrot (5.55 ± 0.22 and 6.42 ± 0.23 log CFU/g/d for L. monocytogenes and S. enterica, respectively). S. enterica displayed higher growth rates at 25°C compared to L. monocytogenes on all vegetables. Overall, these results bridge the knowledge gap concerning the growth kinetics of both S. enterica and L. monocytogenes on various cooked vegetables, offering insights to further enhance food safety.

Investigation of vitality, antibacterial properties, and antagonistic effects of probiotic bacteria in probiotic dairy products

Probiotics play a significant role in the diet, and their contribution to the immune system has been recognised. Their effects on the gastrointestinal system have been evaluated for decades, and the mechanisms of the effects may differ. The aim of the present work was (i) to observe the changes in pH and bacterial counts in common probiotic dairy products, (ii) to isolate probiotic bacteria, (iii) to evaluate antibacterial resistance, and (iv) to evaluate their metabolites' antibacterial effects against common foodborne pathogens. To this end, 20 dairy products labelled "probiotics included" were collected. Isolation and enumeration of Lactobacillus spp., L. acidophilus, and Bifidobacterium spp. were carried out using de Man-Rogosa-Sharp agar (MRS), clindamycin/ciprofloxacin-included MRS agar (MRS-CC), and mupirocin (MUP) supplemented Bifidobacterium selective count agar (BSC-MUP), respectively. Isolates were identified using MALDI-TOF MS analyses, enumerated, and evaluated for their pH values at 1 to 28 d after production, at 1-w intervals. Selected isolates were analysed for antibacterial resistance using the disc diffusion method. Supernatants were then collected from selected probiotics grown in broth, and studied for their antagonistic effects against pathogens using disc diffusion and agar-well diffusion tests. IBM SPSS software was used for statistical analyses. Tests of normality and non-parametric analyses were performed. On the last day of analyses, 75% of the products met the probiotic bacteria vitality requirement of 106 CFU/g. Statistical analyses showed no correlation between increased acidity and bacterial decrease (p &gt; 0.05), while the decrease in pH and bacterial count had significant relationship (p &lt; 0.05). All selected isolates of probiotic bacteria (n = 10) showed multi-drug resistance (MDR) to 10 different common antibiotics. Antagonistic effects were present but weak (inhibition zones were 0 - 4 mm in diameter). When consumed in sufficient amounts, probiotics may inhibit possible pathogen growth in the gut microbiota via metabolites.

Antimicrobial effect of indocyanine green-mediated photodynamic therapy in patients with periodontal disease: A systematic review

Abstract Aim: This systematic review assessed the antimicrobial effect of indocyanine green-mediated photodynamic therapy (ICG-PDT) in patients with periodontal disease. Materials and Methods: Four electronic databases that is, MEDLINE, MEDLINE-In-Process, EMBASE, and Cochrane Library were systematically searched from their inception until December 22, 2022. Randomized controlled trials (RCTs) reporting the antimicrobial effect of ICG-PDT in patients with periodontal disease and published in English were included. The Cochrane risk of bias tool was used to assess the quality of the included RCTs. Two independent reviewers performed all the steps involved in a systematic review (primary and secondary screening, data extraction, and quality assessment). As the data extracted was not suitable for meta-analysis, the evidence was synthesized qualitatively. Results: Overall, seven RCTs from seven publications were included. All included studies had PDT, laser, or photothermal with ICG as the test group while the control group included low-level laser therapy, root surface debridement, and scaling and root planning. The bacterial species assessed across the included studies included Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Tannerella forsythia, Fusobacterium nucleatum, and Treponema denticola. With subtle exceptions, ICG-PDT in combination with root surface debridement and scaling and root planning significantly reduced the growth of periodontal pathogens from baseline. Conclusion: Based on the evidence from the limited studies, ICG-PDT seems to exhibit potent antimicrobial activity against an array of periodontal pathogens in patients with periodontal disease.

Morphological Character and Clorophyl Content Index of Corn Infected with Dowry Disease on Land Applied With Slow Realease Fertilizer Based on Corn Cob Biochar

Downy mildew is a significant disease of corn plants caused by the pathogenic fungus Peronosclerospora maydis, with attack rates reaching 95%. The application of slow-release fertilizer based on corn cob biochar is expected to increase the resistance of corn plants. Similarly, Bacillus sp. and Pseudomonas sp. are known as antagonistic microorganisms. Bacteria can produce antibiotic compounds that hydrolyze fungal cell walls, siderophores, and other antibiotic properties that inhibit pathogen growth. This study aims to determine the morphological characteristics of downy mildew-infected corn on biochar-applied land. Treatments were arranged factorially in a Factorial Randomized Block Design repeated four times. The treatment was the application of slow-release fertilizer from biochar mixed with NPK fertilizer, namely control, slow-release fertilizer, slow-release fertilizer + cow urine, and slow-release fertilizer + cow urine + bacteria (Azobacter and Bacillus). The results showed that slow-release fertilizer gave the best growth to both normal and downy mildew-affected maize plants. The stomata of typical corn leaves were more open with regular vascular bundles, while those affected by downy mildew had more closed and irregular stomata. The chlorophyll content index in downy mildew-affected maize can also improve by applying biochar-based slow-release fertilizer.

The endophytic fungal community plays a crucial role in the resistance of host plants to necrotic bacterial pathogens.

Konjac species (Amorphophallus spp.) are the only plant species in the world that are rich in a large amount of konjac glucomannan (KGM). These plants are widely cultivated as cash crops in tropical and subtropical countries in Asia, including China. Pectobacterium carotovorum subsp. carotovorum (Pcc) is one of the most destructive bacterial pathogens of konjac. Here, we analyzed the interactions between Pcc and susceptible and resistant konjac species from multiple perspectives. At the transcriptional and metabolic levels, the susceptible species A. konjac and resistant species A. muelleri exhibit similar molecular responses, activating plant hormone signaling pathways and metabolizing defense compounds such as phenylpropanoids and flavonoids to resist infection. Interestingly, we found that Pcc stress can lead to rapid recombination of endophytic microbial communities within a very short period (96 h). Under conditions of bacterial pathogen infection, the relative abundance of most bacterial communities in konjac tissue decreased sharply compared with that in healthy plants, while the relative abundance of some beneficial fungal communities increased significantly. The relative abundance of Cladosporium increased significantly in both kinds of infected konjac compared to that in healthy plants, and the relative abundance in resistant A. muelleri plants was greater than that in susceptible A. konjac plants. Among the isolated cultivable microorganisms, all three strains of Cladosporium strongly inhibited Pcc growth. Our results further elucidate the potential mechanism underlying konjac resistance to Pcc infection, highlighting the important role of endophytic microbial communities in resisting bacterial pathogen infections, especially the more direct role of fungal communities in inhibiting pathogen growth.

KARAKTERISASI MORFOLOGI DAN UJI ANTIFUNGI ISOLAT JAMUR Trichoderma spp. DARI TANAH GAMBUT TERHADAP PATOGEN PADA JARAK KEPYAR (Ricinus communis L.)

Castor oil (Ricinus communis L.) is an oil producing commodities that plays a role in meeting industrial and economic needs. Infection with the pathogen fungi caused a decrease in the production of castor oil. Biological control using Trichoderma spp. has been widely used. Trichoderma spp. known as one of the benefical biofungicide because it has high antagonistic properties inhibiting the growth pathogenic fungi. The purpose of this study was to obtain isolates and characters as well antifungal test for Trichoderma spp. isolated from peat soil to control pathogen Aspergillus sp. on castor been (Ricinus communis L.). Trichoderma spp. isolated from peat soil in Meranti Islands, Riau. The antagonistic activity the isolates against pathogen Aspergillus sp. was studied in vitro using dual culture and in vivo assay. In this study, six isolates of Trichoderma spp have isolated. Trichoderma sp. GBA5 has the highest growth rate on PDA and TSM medium. Trichoderma sp. GBA3 and Trichoderma sp. GBA4 were most effective in percentage inhibition of mycelial growth of test pathogen i.e 84,55% and 83,71% respectively. In in vivo assay, only Trichoderma sp. GBA5 inhibited pathogen with the percent infected castor capsule was 51.66%.

Bacterial Strains Isolated from Stingless Bee Workers Inhibit the Growth of Apis mellifera Pathogens.

Apis mellifera bees are an important resource for the local economy of various regions in Argentina and the maintenance of natural ecosystems. In recent years, different alternatives have been investigated to avoid the reduction or loss of colonies caused by pathogens and parasites such as Ascosphaera apis, Aspergillus flavus, and Paenibacillus larvae. We focused on bacterial strains isolated from the intestine of native stingless bees, to elucidate their antagonistic effect on diseases of A. mellifera colonies. For this purpose, worker bees of the species Tetragonisca fiebrigi, Plebeia spp., and Scaptotrigona jujuyensis were captured from the entrance to tree hives and transported to the laboratory, where their intestines were extracted. Twenty bacterial colonies were isolated from the intestines, and those capable of inhibiting enterobacteria in vitro and producing organic acids, proteases, and chitinases were selected. Four genera, Levilactobacillus, Acetobacter, Lactiplantibacillus, and Pantoea, were selected and identified by the molecular marker that codes for the 16S rRNA gene. For inhibition assays, cell suspensions and cell-free suspensions were performed. All treatments showed significant antibacterial effects, in comparison with the controls, against P. larvae and antifungal effects against A. apis and A. flavus. However, the mechanisms by which these bacteria inhibit the growth of these pathogens were not studied.

The Caenorhabditis elegans proteome response to two protective Pseudomonas symbionts.

The Caenorhabditis elegans natural microbiota isolates Pseudomonas lurida MYb11 and Pseudomonas fluorescens MYb115 protect the host against pathogens through distinct mechanisms. While P. lurida produces an antimicrobial compound and directly inhibits pathogen growth, P. fluorescens MYb115 protects the host without affecting pathogen growth. It is unknown how these two protective microbes affect host biological processes. We used a proteomics approach to elucidate the C. elegans response to MYb11 and MYb115. We found that both Pseudomonas isolates increase vitellogenin protein production in young adults, which confirms previous findings on the effect of microbiota on C. elegans reproductive timing. Moreover, the C. elegans responses to MYb11 and MYb115 exhibit common signatures with the response to other vitamin B12-producing bacteria, emphasizing the importance of vitamin B12 in C. elegans-microbe metabolic interactions. We further analyzed signatures in the C. elegans response specific to MYb11 or MYb115. We provide evidence for distinct modifications in lipid metabolism by both symbiotic microbes. We could identify the activation of host-pathogen defense responses as an MYb11-specific proteome signature and provide evidence that the intermediate filament protein IFB-2 is required for MYb115-mediated protection. These results indicate that MYb11 not only produces an antimicrobial compound but also activates host antimicrobial defenses, which together might increase resistance to infection. In contrast, MYb115 affects host processes such as lipid metabolism and cytoskeleton dynamics, which might increase host tolerance to infection. Overall, this study pinpoints proteins of interest that form the basis for additional exploration into the mechanisms underlying C. elegans microbiota-mediated protection from pathogen infection and other microbiota-mediated traits.IMPORTANCESymbiotic bacteria can defend their host against pathogen infection. While some protective symbionts directly interact with pathogenic bacteria, other protective symbionts elicit a response in the host that improves its own pathogen defenses. To better understand how a host responds to protective symbionts, we examined which host proteins are affected by two protective Pseudomonas bacteria in the model nematode Caenorhabditis elegans. We found that the C. elegans response to its protective symbionts is manifold, which was reflected in changes in proteins that are involved in metabolism, the immune system, and cell structure. This study provides a foundation for exploring the contribution of the host response to symbiont-mediated protection from pathogen infection.

Green synthesis of silver nanoparticles from Fraxinus angustifolia Vahl. Extract: Characterization and assessment of their biological activities

Nanoparticle synthesis for biological devices is one of the most promising research fields invading the world. This work aimed to synthesize ecofriendly silver nanoparticles (AgNPs) with enhanced biological activities. A green method was adopted to synthesize, for the first time, AgNPs from Fraxinus angustifolia extracts. The AgNPs structural and morphological properties were characterized. Their antioxidant, antimicrobial and antidiabetic effects were investigated. Their cytotoxic and genotoxic effects were explored using the novel method of acetocarmine dye. Results confirmed the formation of stable, mono-dispersed and spheric nanoparticles with a Face-Centered Cubic crystalline structure, sized from 30.12 to 49.62 nm. The AgNPs showed high antioxidant activities (DPPH, β-carotene bleaching and total antioxidant activities). They significantly inhibited the growth of the multi-drug resistant pathogens Escherchia coli and Candida tropicalis. However, they showed moderate inhibitory activity against biofilm production of E. coli and C. tropicalis, with 65 and 63% inhibition, respectively. F. angustifolia AgNPs exhibited interesting antidiabetic activity, exceeding that of the acarbose. Interestingly, the acetocarmine stanning was approved as an exploration technique for the screening of cytotoxic and genotoxic effects. Allium cepa epidermis tissues treated by the AgNPs presented a visible morphological change in the cell membrane and the disruption of the nuclear envelope. The obtained results highlighted the versatile biological potential of F. angustifolia AgNPs allowing their use as green nanomaterials in food preservation, pharmaceutical formulation and in food quality prospecting. This work also affords a new method for screening possible cytotoxicity and genotoxicity of nanomaterials in agri-food applications.

Pathogenecity and in-vitro Assessment of Some Fungicides on the Mycelial Growth of Rice Blast Pathogen (Magnaporthe oryzae B.Cauch) in Jigawa State, Nigeria

Pathogenecity and in-vitro Assessment of Some Fungicides on the Mycelial Growth of Rice Blast Pathogen (Magnaporthe oryzae B.Cauch) in Jigawa State, Nigeria

Exploring the Prospective Role of Propolis in Modifying Aging Hallmarks.

Aging populations worldwide are placing age-related diseases at the forefront of the research agenda. The therapeutic potential of natural substances, especially propolis and its components, has led to these products being promising agents for alleviating several cellular and molecular-level changes associated with age-related diseases. With this in mind, scientists have introduced a contextual framework to guide future aging research, called the hallmarks of aging. This framework encompasses various mechanisms including genomic instability, epigenetic changes, mitochondrial dysfunction, inflammation, impaired nutrient sensing, and altered intercellular communication. Propolis, with its rich array of bioactive compounds, functions as a potent functional food, modulating metabolism, gut microbiota, inflammation, and immune response, offering significant health benefits. Studies emphasize propolis' properties, such as antitumor, cardioprotective, and neuroprotective effects, as well as its ability to mitigate inflammation, oxidative stress, DNA damage, and pathogenic gut bacteria growth. This article underscores current scientific evidence supporting propolis' role in controlling molecular and cellular characteristics linked to aging and its hallmarks, hypothesizing its potential in geroscience research. The aim is to discover novel therapeutic strategies to improve health and quality of life in older individuals, addressing existing deficits and perspectives in this research area.

The effect of local use of etiotropic drugs on the oropharyngeal microbiota in children with acute respiratory infection

Introduction. The microbiota of the oral cavity and oropharynx, actively interacts with the epithelium of the mucous membrane and the immune system, creates antagonistic conditions for the growth and reproduction of pathogens. Microbiocenosis-preserving therapy can provide conditions for maintaining colonization resistance and reduce the likelihood of adhesion of respiratory viruses.Aim. To evaluate the effect of local use of various antimicrobial drugs on the microbiota of the oropharyngeal mucosa in children with acute respiratory infection.Materials and methods. 120 children (5–10 years old) with acute respiratory infection were divided into three groups, in which they were used as part of complex therapy: in group 1st – hexetidine-containing aerosol, in group 2nd – a children’s spray containing gramicidin S and cetylpyridinium chloride, in the 3rd – 0.01% solution of benzyldimethyl-myristoylamino-propylammonium. On the 1st and 12th days of observation, participants had a throat swab taken to study the state of the oropharyngeal microbiota using 16S rRNA sequencing. The results obtained were compared with those of healthy peers.Results. According to sequencing data, the microbiota of participants in all groups before treatment differed from the microbiota of healthy peers in terms of alpha and beta diversity, as well as in the results obtained by the nearest balance method. Local use of antiseptic drugs influenced the microbiota at the level of species and genera of microorganisms. After treatment in the 2nd group, in contrast to the 1st and 3rd, statistically significant changes in the balances at the level of microorganism species were revealed towards the indicators of healthy peers.Conclusions. A combined drug containing cetylpyritinium chloride and the bacteriocin-like antimicrobial peptide gramicidin S demonstrated no negative effect on commensal microbiota and contributed to the stabilization of the regional microbiota.

Heme sequestration by hemophilin from Haemophilus haemolyticus reduces respiratory tract colonization and infection with non-typeable Haemophilus influenzae.

The microbiome provides a critical layer of protection against infection with bacterial pathogens. This protection is accomplished through a variety of mechanisms, including interference with pathogen growth and adherence to host cells. In terms of immune defense, another way to prevent pathogens from establishing infections is by limiting the availability of nutrients, referred to as nutritional immunity. Restricting pathogen access to iron is a central component of this approach. Here, we uncovered an example where these two strategies intersect to impede infection with the respiratory tract bacterial pathogen Haemophilus influenzae. Specifically, we find that a non-pathogenic (commensal) bacterium closely related to H. influenzae called Haemophilus haemolyticus improves protection against H. influenzae by limiting the ability of this pathogen to access iron. These findings suggest that beneficial members of the microbiome improve protection against pathogen infection by effectively contributing to host nutritional immunity.

RHIZOBACTERIA AS ANTAGONIST AGAINST Fusarium oxysporum CAUSING TOMATO WILT

Tomatoes (Lycopersicon esculentum L.) are the most extensively grown vegetable in the world. It belongs to the Solanaceae family and is commonly planted for its tasty fruits. Pests, weeds, diseases, and parasites are just a few of the numerous variables that significantly affect tomato growth and yield. The most common disease affecting tomatoes is fusarium wilt. Fifteen rhizobacterial strains were identified by morphological and biochemical analyses in this work, and they were employed as an antagonist against Fusarium oxysporum f.sp. lycopersici. Fifteen isolates were investigated for their antagonistic properties against Fusarium oxysporum f.sp. lycopersici using an invitro dual culture approach. The growth of Fusarium oxysporum f.sp. lycopersici was suppressed by each isolate. Out of the 15 rhizobacteria isolates, isolate RBS-5 exhibited the highest level of growth inhibition and strongly suppressed the development of Fusarium oxysporum f.sp. lycopersici, resulting in a 57.28 percent reduction in pathogen growth as compared to the control. The development of Fusarium oxysporum f.sp. lycopersici was suppressed by isolates RBS-12, RBS-6, and RBS-15, in decreasing order of merit, compared to the control by 53.7, 51.91, and 51.73 percent. Isolate RBS-13 showed the least amount of pathogen growth inhibition 20.83 percent. The data was statistically analyzed.