Growth Of Pathogens Research Articles

Fermentation of sugar kelp (Saccharina latissima): exploring the potential of the kelp’s native microbiota as starter culture and the microbiological food safety of fermented products

This study investigated the use of native microbiota from the sugar kelp Saccharina latissima in the form of fermented kelp fluid (FKF) from a spontaneous anaerobic fermentation process as a starter culture (SC) for the fermentation of freshly harvested biomass of the same species. Rapid (<48 h) acidification (pH < 4.3) was achieved for S. latissima inoculated with FKF, at a fermentation temperature of 21°C. Kelp inoculated with a commercial strain of Lactiplantibacillus plantarum (Lp, positive control) reached a similar pH level after 5 days, while kelp with no SC (negative control) did not reach a pH level below 4.3 within 9 days. The microbiota of the FKF-SC as well as the FKF-inoculated S. latissima samples was dominated by lactic acid bacteria (LAB) identified as L. plantarum. The SC in these samples successfully converted mannitol into lactic acid as the main fermentation product. In contrast, a higher production of acetic acid and ethanol was measured in the negative control samples than in other groups; this reflects a different microbial profile, including marine bacteria which could not be identified by MALDI-TOF biotyping. Challenge trials of S. latissima samples from experimental and commercial fermentation processes with Bacillus cereus did not result in the growth of this food pathogen, even at pH levels within a viable range for this species (pH > 4.3). These preliminary results provide a foundation for further isolation of suitable SCs for kelp fermentation in commercial production and for assessing the food safety of fermented kelp. Efficient and safe fermentation processes will increase sustainability in kelp production and enable a broader use of kelp ingredients in food applications.

In-vitro effectiveness of aqueous extract of organic compost against Helminthosporium turcicum (cryptogamic disease pathogen of maize)

Sustainable agriculture requires the application of biofertilizers and biopesticides in farming systems. The aim of the study was to analyze in-vitro the effect of aqueous extracts from organic compost on the development of cryptogamic disease in maize plants for yield improvement. The study was carried out in the laboratory using a pure strain of Helminthosporium turcicum previously isolated from infected maize leaves showing symptoms of the disease. Aqueous substrates of unsterilized and sterilized composts, with the concentrations 0.5, 1.0 and 2.0 mL were respectively mixed with liquid PDA at 19.5; 19 and 18 mL for a final volume of 20 ml, then aseptically poured into 90 mm diameter Petri dishes under the laminar flow hood. After solidification, 7 mm-diameter mycelial discs from young H. turcicum cultures were deposited on the agar pellets. 48 hours after incubation, mycelial growth was measured 4 times until the positive control Petri dish was invaded by mycelial filaments. The results showed that the mycelial growth of the H. turcicum strain in the presence of the sterilized aqueous compost extract was significantly reduced. Increasing the concentration significantly inhibited strain growth to the order of 95.89% at a concentration of 2 mL sterilized aqueous compost extract. Similarly, in the presence of the unsterilized aqueous compost extract, the mycelial growth of H. turcicum was also reduced. The Increasing concentration inhibited the pathogen growth by up to 76.92%, at the concentration of 2 mL. These results showed that the aqueous extract of organic compost contains compounds that could be responsible for producing suppressive substances accountable for the mechanisms inhibiting the mycelial growth of H. turcicum. Int. J. Agril. Res. Innov. Tech. 14(2): 62-73, December 2024

Probiotic and postbiotic interference exhibit anti-adhesion effects against clinical methicillin-resistant Staphylococcus aureus (MRSA) and impede MRSA-induced intestinal epithelial hyper-permeability in HT-29cell line.

This study investigates the dynamics of MRSA de-colonization on HT-29cell line using effective strategies like probiotics and postbiotics. Exploring novel alternatives to combat infections caused by antibiotic-resistant pathogens is an urgent need. Harnessing the antagonistic properties of live probiotics and their heat-killed preparations (postbiotics) to curb the growth of AMR pathogens represents a promising and essential area of contemporary research. This study was designed to evaluate the anti-adhesion properties of indigenous probiotics (Limosilactobacillus fermentum Lf1 and Lactiplantibacillus plantarum A5), as well as standard reference strains (Lacticaseibacillus rhamnosus GG and Lactobacillus acidophilus NCFM), and their heat-killed postbiotic preparations against clinical MRSA isolates (MRSA12/206 and 5/255) on the HT-29cell line. ATR-FTIR-based functional group characterization of the postbiotic preparations revealed the heat-induced alterations in cell surface molecules and architecture. Both probiotic and postbiotic preparations were non-cytotoxic to HT-29cells. The probiotic intervention, via protective, competitive, and displacement modes, significantly (p<0.05) reduced the adhesion of MRSA isolates to HT-29cells, with the protective and competitive modes showing greater efficacy. In contrast, heat-killed probiotics demonstrated notable anti-MRSA adhesion effects across all three modes (protective, competitive, and displacement). In comparison, heat-killed cells exhibited a superior anti-adhesion capability compared to live cells, likely due to the enhanced accessibility of microbe-associated molecular patterns and adhesion sites following heat treatment. Furthermore, co-treatment of MRSA with probiotic strains substantially (p<0.05) reduced FITC-dextran transflux across the HT-29cell monolayer. In conclusion, this study highlights the superior anti-adhesion efficacy of heat-killed postbiotics over live probiotic cells against MRSA isolates. It underscores the further need for pre-clinical and in-vivo investigations to validate the anti-MRSA colonization and gut barrier prophylactic or therapeutic potential of the investigated probiotics and postbiotics. Thus, the present study documents and supports the alternative to antibiotics potential of probiotics and postbiotics.

Recent drying technologies used for drying poultry litter (principles, advantages and disadvantages): A comprehensive review.

Wet poultry litter creates an environment that accelerates the growth of bacteria and pathogens, leading to increased ammonia release. A practical way to reduce these adverse effects is heat treatment (drying). This work evaluated different methods for poultry litter drying and presented their principles, advantages, and disadvantages. Oven dryers are not recommended for continual drying due to their low energy efficiency, but decreasing water activity can prevent microbial growth. Rotary dryers provide homogeneous drying, but they are not suitable for drying fragile materials. Freeze drying preserves heat-sensitive ingredients, but the drying duration is high and classified as a high-cost drying technique. Microwave drying technology surpasses conventional methods in achieving both high product quality and energy efficiency. Solar drying emerges as the most economically viable, practical, and environmentally sound method for poultry litter desiccation. However, improperly controlled mass and heat transfer throughout the drying process can compromise product integrity. The use of combined dryers has not been thoroughly evaluated, although they may be more effective due to their synergistic results. This study is helpful for researchers who aim to reduce the adverse effects of poultry litter and manage it more effectively using heat treatment methods.

Role of probiotics in skin health: Current trends and future perspectives

The human skin is a complex ecosystem that plays a crucial role in maintaining overall health and well-being. In recent years, there has been a growing interest in the potential benefits of probiotics in promoting skin health. Probiotics are live microorganisms that confer health benefits when administered in adequate amounts. Probiotics have been shown to have a positive impact on the skin microbiome, promoting the growth of beneficial microorganisms and inhibiting the growth of pathogens. In addition to their effects on the skin microbiome, probiotics have also been shown to have anti-inflammatory, antioxidant, and immune-modulating effects, which may contribute to their beneficial effects on skin health. Their role in skin health is a relatively new area of research. This review aims to provide an overview of the current state of knowledge on the role of probiotics in skin health, including their potential benefits, mechanisms of action, and future perspectives.

БИОЛОГИЧЕСКИЙ КОНТРОЛЬ КОРНЕВЫХ ГНИЛЕЙ, ВЫЗЫВАЕМЫХ ГРИБАМИ РОДА ARMILLARIA

The aim of the study is to evaluate the prospects for using Siberian strains of macro- and microscopic fungi for biological control of the root pathogen Armillaria borealis, which is the most common causative agent of root rot from the Armillaria mellea sensu lato complex in Central Siberia. In vitro, the prospects for using ascomycete (Trichoderma asperellum) and basidiomycete (Ganoderma lucidum, Fomitopsis pinicola) fungi to limit the growth of armillaria pathogens were demonstrated. The K6-15 T. asperellum strain has the maximum antifungal activity, quickly and effectively inhibiting the growth of A. borealis on agar medium and plant substrate – up to 67 and 50 % growth inhibition, respectively. When the mycelium of the antagonist and phytopathogens comes into contact on both types of nutrient substrates, the interaction reaction is assessed at 4 (the antagonist grows around the colony of the phytopathogen) and 5 (the antagonist continues to grow at an unchanged rate over the colony of the phytopathogen) points. Strain K6-15 also exhibits high mycoparasitic activity (3 points), colonizing 100 % of the area of the mycelial film of A. borealis within 7–8 days of cultivation. Fast-growing saprotrophic basidiomycetes G. lucidum and F. pinicola can be considered as promising biocontrol agents. The studied strains Fp5-15 and Gl5-16 are capable of parasitizing on the mycelial film of A. borealis (fouling area of 100 % within 12–14 days); their antifungal activity is maximal on the plant substrate (52–54 % inhibition of the growth of the phytopathogenic fungus) and exceeds the indicator of strain K6-15 T. asperellum, and the reaction of interaction in the contact zone with the colony of phytopathogens is estimated at 5 points.

Convergent evolution of oxidized sugar metabolism in commensal and pathogenic microbes in the inflamed gut

Inflammation-associated perturbations of the gut microbiome are well characterized, but poorly understood. Here, we demonstrate that disparate taxa recapitulate the metabolism of the oxidized sugars glucarate and galactarate, utilizing enzymatically divergent, yet functionally equivalent, gud/gar pathways. The divergent pathway in commensals includes a putative 5-KDG aldolase (GudL) and an uncharacterized ABC transporter (GarABC) that recapitulate the function of their non-homologous counterparts in pathogens. A systematic bioinformatic search for the gud/gar pathway in gut microbes identified 887 species putatively capable of metabolizing oxidized sugars. Previous studies showed that inflammation-derived nitrate, formed by nitric oxide reacting with superoxide, promotes pathogen growth. Our findings reveal a parallel phenomenon: oxidized sugars, also produced from reactions with nitric oxide, serve as alternative carbon sources for commensal microbes. Previously considered a pathogen virulence factor, oxidized sugar metabolism is also present in specific commensals and may contribute to their increased relative abundance in gastrointestinal inflammation.

Construction of Composite Microorganisms and Their Physiological Mechanisms of Postharvest Disease Control in Red Grapes

Red grapes often suffer from postharvest diseases like blue mold and black mold caused by Penicillium expansum and Aspergillus niger. Biological control using beneficial yeasts and bacteria is an effective method to manage these diseases. Rhodotorula sp. and Bacillus sp. are effective microorganisms for the control of postharvest diseases of red grapes. This study combined two yeast strains (Rhodotorula graminis and Rhodotorula babjevae) and two bacterial strains (Bacillus licheniformis and Bacillus velezensis) to investigate their biological control effects on major postharvest diseases of red grapes and explore the underlying physiological mechanisms. Research showed that compound microorganism W3 outperformed the others; it reduced spore germination and germ tube growth of P. expansum and A. niger, while its volatiles further inhibited pathogen growth. Additionally, the treatment enhanced the antioxidant capacity of grapes and increased resistance to pathogens by boosting peroxidase activities, superoxide dismutase, catalase and ascorbate peroxidase, phenylalanine ammonolyase, and polyphenol oxidase. Furthermore, the combined treatment increased the activity and accumulation of antifungal compounds such as total phenols and flavonoids, thereby improving disease resistance and reducing decay. Therefore, composite microorganisms combining various antagonistic strains may offer a viable substitute for tackling postharvest diseases in red grapes.

Assessment of the Microbiological Potential and Spectroscopic Properties of New Imino-1,3,4-Thiadiazoles Showing the ESIPT Effect Strongly Enhanced by Aggregation

There is currently a growing interest in imino derivatives of compounds such as thiadiazoles and other groups of compounds whose extended π-electron systems enhance their photophysical properties. These compounds also show low toxicity and strong antifungal activity, making them effective against fungal pathogens in crops. For the above reasons, in the first part of the paper, the structure of the selected analogs was considered, and detailed spectroscopic analyses were conducted focusing on the excited state intramolecular proton transfer (ESIPT) process taking place in the same. Measurements were taken in terms of absorption spectroscopy and electron fluorescence, synchronous spectra, and fluorescence lifetimes, as well as calculations of fluorescence quantum efficiency in selected solvents and concentrations. In the spectral observations, the ESIPT process was manifested in several solvents as very distinct dual fluorescence. Moreover, in selected molecules, this phenomenon was strongly related to molecular aggregation, which was associated with not very efficient but nonetheless visible fluorescence of the AIE (Aggregation-Induced Emission) type. In the second part of the paper, a detailed preliminary study is presented exploring the microbiological properties of selected imino-1,3,4-thiadiazole derivatives in the context of their potential applicability as inhibitors affecting the development and growth of some of the most important fungal pathogens attacking cereal crops and posing an increasing threat to modern agriculture. Overall, the research presented in this article provides a detailed, experimental analysis of the spectroscopic properties of selected imino-thiadiazoles and points to their potential use as novel and effective solutions capable of limiting the growth and development of fungal pathogens in cereals.

LACCASE35 Enhances Lignification and Resistance Against Pseudomonas syringae pv. actinidiae Infection in Kiwifruit.

Kiwifruit bacterial canker, a highly destructive disease caused by Pseudomonas syringae pv. actinidiae (Psa), seriously affects kiwifruit (Actinidia spp.) production. Lignin deposition in infected cells serves as a defense mechanism, effectively suppressing pathogen growth. However, the underlying process remains unclear. In this study, we determined that Psa infection leads to a significant increase in S-lignin accumulation in kiwifruit. The S/G ratio in lignin was higher in a Psa-resistant cultivar than in a Psa-sensitive cultivar. Furthermore, kiwifruit laccase 35 (AcLac35), encoding an enzyme in the lignin biosynthesis pathway with characteristic laccase activity, showed tissue-specific expression in plants and was upregulated following infection by Psa. Overexpressing AcLac35 in kiwifruit leaves resulted in greater lignin content than in wild-type leaves, leading to the formation of thicker cell walls, and also activated plant-pathogen interactions and MAPK pathways, thereby enhancing resistance against Psa infection. Yeast one-hybrid assays, dual-LUC reporter assays, electrophoretic mobility shift assays, and transient injection experiments indicated that SQUAMOSA PROMOTER-BINDING PROTEIN-LIKE 9 (AcSPL9) can bind to the AcLac35 promoter, thereby positively regulating its expression. Moreover, overexpression of AcSPL9 increased lignin accumulation in kiwifruit leaves, enhancing resistance to Psa, while virus-induced gene silencing of AcSPL9 expression reduced this resistance. Our findings reveal the function of AsSPL9-AcLac35 in kiwifruit, providing insight into enhancing resistance against Psa in kiwifruit.

Impact of fresh-cut onion types and flavonoid profiles on the survival kinetics of foodborne pathogen during refrigerated storage.

This study investigated the effect of onion flavonoid profiles on the growth, survival, and/or death kinetics of foodborne pathogens in fresh-cut onions at 4°C. Fresh-cut white, yellow, red, and sweet onions were inoculated with separate four-strain cocktail(s) of nalidixic acid-adapted Salmonella spp., Escherichia coli O157:H7, and Listeria monocytogenes achieving a 4 to 5 log CFU g-1. The samples were stored in clam shell containers at 4°C and 70±2% relative humidity for 14days. Additionally, flavonoid profiles were determined on uninoculated control samples stored under similar conditions using standard chromatography techniques, with quercetin derivatives identified as the predominant flavonoids. Results indicated significant differences in pathogen reduction and survival across onion types. Salmonella and E. coli O157:H7 populations declined by 2 to 4 log after 14days, while L. monocytogenes populations increased on white and red onions, remained stable on yellow onions, and declined on sweet onions. Red onions contained the highest flavonoid concentrations, followed by sweet, yellow, and white onions. Notably, despite having similar flavonoid levels, sweet onions showed greatest reduction of tested pathogens than red onions, suggesting that factors beyond flavonoid content may contribute to pathogen reduction. These findings provide new insights into the behavior of foodborne pathogens in fresh-cut onions and highlight the potential for flavonoids to influence pathogen survival during refrigerated storage.

ι-Carrageenan Manganese Oxide Bionanocomposites as a Promising Solution to Agricultural Challenges

Agriculture faces numerous challenges: infectious diseases through phytopathogens and soil nutrient deficiencies hinder plant growth, reducing crop yields. Biopolymer nanocomposites offer promising solutions to these challenges. In this work, we synthesize and characterize novel bionanocomposites (ι-CG-Mn) of manganese (hydr)oxide nanoparticles (approx. 3 to 11 nm) embedded in the matrix of the natural polysaccharide ι-carrageenan (ι-CG). Using spectroscopic methods we verify the presence of the nanoparticles in the polymer matrix while leaving the polysaccharide structural characteristics unaffected. Elemental analysis determines the mass content of metal ions in the ι-CG-Mn to be approx. 1 wt%. Electron microscopy techniques show the supramolecular organization of the ι-CG-Mn and the homogeneous nanoparticle distribution in the polymer matrix, while thermal analysis reveals that the bionanocomposite maintains high thermal stability. Moreover, the co-incubation of the phytopathogen Clavibacter sepedonicus with ι-CG-Mn inhibits the pathogen growth by 67% compared to the control. Our bionanocomposites demonstrate (1) strong bactericidal activity and (2) potential as microfertilizers that stimulate agricultural plant growth through the dosage of metal ions. These properties arise from the bioactivity of the widely available, naturally sulfated polysaccharide biopolymer matrix, combined with the antimicrobial effects of manganese (hydr)oxide nanoparticles, which together enhance the efficacy of the biocomposite. The non-toxic, biocompatible, and biodegradable nature of this biopolymer satisfies the high environmental demands for future biotechnological and agricultural technologies.

Nanoparticle-Doped Antibacterial and Antifungal Coatings.

Antimicrobial polymeric coatings rely not only on their surface functionalities but also on nanoparticles (NPs). Antimicrobial coatings gain their properties from the addition of NPs into a polymeric matrix. NPs that have been used include metal-based NPs, metal oxide NPs, carbon-based nanomaterials, and organic NPs. Copper NPs and silver NPs exhibit antibacterial and antifungal properties. So, when present in coatings, they will release metal ions with the combined effect of having bacteriostatic/bactericidal properties, preventing the growth of pathogens on surfaces covered by these nano-enhanced films. In addition, metal oxide NPs such as titanium dioxide NPs (TiO2 NPs) and zinc oxide NPs (ZnONPs) are used as NPs in antimicrobial polymeric coatings. Under UV irradiation, these NPs show photocatalytic properties that lead to the production of reactive oxygen species (ROS) when exposed to UV radiation. After various forms of nano-carbon materials were successfully developed over the past decade, they and their derivatives from graphite/nanotubes, and composite sheets have been receiving more attention because they share an extremely large surface area, excellent mechanical strength, etc. These NPs not only show the ability to cause oxidative stress but also have the ability to release antimicrobial chemicals under control, resulting in long-lasting antibacterial action. The effectiveness and life spans of the antifouling performance of a variety of polymeric materials have been improved by adding nano-sized particles to those coatings.

Wheat Leaf Rust Effector Pt48115 Localized in the Chloroplasts and Suppressed Wheat Immunity.

Wheat leaf rust caused by Puccinia triticina (Pt) is a prevalent disease worldwide, seriously threatening wheat production. Pt acquires nutrients from host cells via haustoria and secretes effector proteins to modify and regulate the expression of host disease resistance genes, thereby facilitating pathogen growth and reproduction. The study of effector proteins is of great significance for clarifying the pathogenic mechanisms of Pt and effective control of leaf rust. Herein, we report a wheat leaf rust candidate effector protein Pt48115 that is highly expressed in the late stages of infection during wheat-Pt interaction. Pt48115 contains a signal peptide with a secretory function and a transit peptide that can translocate Pt48115 to the host chloroplasts. The amino acid sequence polymorphism analysis of Pt48115 in seven different leaf rust races showed that it was highly conserved. Pt48115 inhibited cell death induced by Bcl-2-associated X protein (BAX) from mice or infestans 1 (INF1) from Phytophthora infestans in Nicotiana benthamiana and by DC3000 in wheat, and its 145-175 amino acids of the C-terminal are critical for its function. Furthermore, Pt48115 inhibited callose deposition and reactive oxygen species accumulation in the wheat cultivar Thatcher, demonstrating that it is an effector that enhances Pt virulence by suppressing wheat defense responses. Our findings lay a foundation for future studies on the pathogenesis of Pt during wheat-fungus interaction.

The Utilization of Bacillus spp. as Endophytes in Enhancing Plant Resistance and Health Against Fusarium oxysporum : A Mini Review

Fusarium oxysporum is a destructive pathogen responsible for significant losses in chili (Capsicum spp.) and other crops. Traditional chemical control methods pose environmental and health risks, highlighting the need for sustainable alternatives. This review explores the role of Bacillus spp. as endophytic biocontrol agents in combating F. oxysporum. Species such as B. subtilis, B. mojavensis, and B. velezensis exhibit antifungal activity through the production of hydrolytic enzymes (e.g., glucanase, cellulase, and chitinase) and secondary metabolites like lipopeptides and antibiotics, which inhibit pathogen growth. Furthermore, these bacteria enhance plant health by inducing systemic resistance, promoting root development, and creating a rhizosphere environment unfavorable to pathogens. Their synergistic interactions with other beneficial microorganisms further bolster plant defense and productivity. Molecular and physiological analyses confirm the efficacy of Bacillus spp. in reducing disease severity and improving plant resilience. Continued research into their mechanisms and field application can support more sustainable agricultural practices.

Comparative Analysis of the Probiotic Features of Lysinibacillus and Enterobacter Strains Isolated from Gut Tract of Triploid Cyprinid Fish.

Gut mucosal immunity of teleost is mainly governed by mucosa-associated lymphoid tissues (MALT) and indigenous microbiota on mucosal surfaces of gut tract, which can confer protection against pathogenic invasion. However, the probiotic features of bacterial isolates from gut tract of triploid cyprinid fish (TCF) were largely unclear. In this study, Lysinibacillus and Enterobacter strains were isolated for probiotic identification. Whole genome sequencing (WGS) analysis indicated that Lysinibacillus and Enterobacter isolates possessed a variety of functional genes associated with probiotic features. Biofilm-forming activity (BFA) were one of the most important probiotic features, which can enable probiotic strains to communicate with indigenous microbiota by forming sessile community and then confer protection against stressors and invading pathogens. In this study, Lysinibacillus and Enterobacter isolates displayed high levels of BFA, hydrophobicity as well as aggregating potentials. Moreover, supernatants of probiotic isolates not only decreased pathogenic BFA and growth activity, but also showed high decomposing activity to macronutrients. These results indicated that probiotic isolates from gut tract of TCFs may pose protective roles in health of farmed fish.

Therapeutic potential of Bacillus-derived lipopeptides in controlling enteropathogens and modulating immune responses to mitigate post-weaning diarrhea in swine.

Post-weaning diarrhea (PWD) is a major concern for pig producers, as stress and early weaning increase susceptibility to enteropathogens like enterotoxigenic Escherichia coli (ETEC) and Salmonella enterica subsp. enterica serovar Typhimurium (S. Typhimurium). This study explores the immunomodulatory and antimicrobial properties of lipopeptide extracts (LPEs) from Bacillus strains which contain surfactin (SF) - an immunomodulatory lipopeptide - and their potential in mitigating PWD. Pre-incubation with LPEs from B. subtilis TC12, containing 1, 40 and 60µg/ml SF, stimulated TNF-α production significantly (p < 0.05) in LPS-challenged RAW 264.7 cells. In contrast, B. velezensis MFF 2.2 LPE, containing 0.1 and 1µg/ml SF, reduced TNF-α production by macrophages after LPS-challenge. The production of IFN-γ by these cells was not affected by pre-incubation with any of the extracts. On the other hand, all treatments significantly decreased (p < 0.05) IL-10 production. LPEs significantly reduced (p < 0.05) NO production; however, neither TC12 nor MFF 2.2 LPEs affected macrophage phagocytic activity or bactericidal capacity and, in addition, LPEs showed bacteriostatic activity towards S. Typhimurium and ETEC. Also, LPEs did not affect RAW 264.7 viability (> 90%) in concentrations up to 60µg/ml SF for TC 12 and 1µg/ml for MFF 2.2. These findings suggest that LPEs from native Bacillus possess immunomodulatory and antimicrobial properties, which could help control inflammation and inhibit pathogen growth during piglet weaning. According to preliminary in vivo studies, LPEs might offer a promising alternative to reduce antibiotic usage in pig husbandry.

Prevalence, misclassification, and clinical consequences of the heteroresistant phenotype in Escherichia coli bloodstream infections in patients in Uppsala, Sweden: a retrospective cohort study.

Antibiotic heteroresistance is a common bacterial phenotype characterised by the presence of small resistant subpopulations within a susceptible population. During antibiotic exposure, these resistant subpopulations can be enriched and potentially lead to treatment failure. In this study, we examined the prevalence, misclassification, and clinical effect of heteroresistance in Escherichia coli bloodstream infections for the clinically important antibiotics cefotaxime, gentamicin, and piperacillin-tazobactam. We conducted a retrospective cohort analysis of patients (n=255) admitted to in-patient care and treated for Ecoli bloodstream infections within the Uppsala region in Sweden between Jan 1, 2014, and Dec 31, 2015. Patient inclusion criteria were admission to hospital on suspicion of infection, starting systemic antibiotics at the time of admission, positive blood cultures for the growth of Ecoli upon admission, and residency in the Uppsala health-care region at the time of admission. Exclusion criteria were growth of an additional pathogen than Ecoli in blood cultures taken at admission or previous inclusion of the patients in the study for another bloodstream infection. Antibiotic susceptibility of preserved blood culture isolates of Ecoli was assessed for cefotaxime, gentamicin, and piperacillin-tazobactam by disk diffusion and breakpoint crossing heteroresistance (BCHR) was identified using population analysis profiling. The clinical outcome parameters were obtained from patient records. The primary outcome variable was length of hospital stay due to the Ecoli bloodstream infection, defined as the time between admission and discharge from inpatient care as noted on the physician's notes. Secondary outcomes were time to fever resolution, admission to intermediary care unit or intensive care unit during time in hospital, switching or adding another intravenous antibiotic treatment, re-admission to hospital within 30days of original admission, recurrent Ecoli infection within 30days of admission to hospital, and all-cause mortality within 90days of admission. A total of 255participants with a corresponding Ecoli isolate (out of 500screened for eligibility) met theinclusion criteria, with 135female patients and 120male patients. One (<1%) of 255strains was BCHR for cefotaxime, 109 (43%) of 255strains were BCHR for gentamicin, and 22 (9%) of 255strains were BCHR for piperacillin-tazobactam. Clinical susceptibility testing misclassified 120 (96%) of 125heteroresistant bacterial strains as susceptible. The BCHR phenotypes had no correlation to length of hospital stay due to the Ecoli bloodstream infection. However, patients with piperacillin-tazobactam BCHR strains who received piperacillin-tazobactam had3·1times higher odds for admittance to the intermediate care unit (95% CI 1·1-9·6, p=0·041) than the remainder of the cohort, excluding those treated with gentamicin. Similarly, those infected with gentamicin BCHR who received gentamicin showed higher odds for admittance to the intensive care unit (5·6 [1·1-42·0, p=0·043]) and mortality (7·1[1·2-49·2, p=0·030]) than patients treated with gentamicin who were infected with non-gentamicin BCHR Ecoli. In a cohort of patients with Ecoli bloodstream infections, heteroresistance is common and frequently misidentified in routine clinical testing. Several negative effects on patient outcomes are associated with heteroresistant strains. Wallenberg Foundation, Swedish Research Council, and US National Institutes Of Health.

Influence of Eimeria spp. and Clostridium perfringens Infection on Growth Performance and Toltrazuril Residues in Chickens.

Coccidiosis and necrotic enteritis are among the most common diseases affecting poultry, with economic impact due to reduced production and the costs of treatment and prevention. Eimeria invasion contributes to gut damage that promotes the growth of other harmful pathogens, such as Clostridium perfringens. Coccidiostats, with toltrazuril as an example, are widely used to control these infections. In this study, we assessed the effects of Eimeria spp. infection and coinfection with Eimeria spp. and Clostridium perfringens on chicken weight and toltrazuril concentrations, along with two metabolites-toltrazuril sulfoxide and toltrazuril sulfone-using liquid chromatography coupled with mass spectrometry. The analysis of liver and muscle samples showed lower levels of residues in groups challenged with Eimeria spp. In the case of combined Eimeria and C. perfringens infection, no significant differences were observed. These findings suggest that the combination of Eimeria and C. perfringens does not significantly alter the residue levels of toltrazuril and its metabolites, providing valuable insight into the pharmacokinetics of toltrazuril in poultry under infection conditions. This research contributes to optimizing drug use and residue management in poultry production.

Additive Effects of Natural Plant Extracts/Essential Oils and Probiotics as an Antipathogenic Topical Skin Patch Solution for Acne and Eczema.

This work leverages the additive antipathogenic effects of natural extracts/essential oils (EOs) and probiotics for the treatment of acne vulgaris associated with Cutibacterium acnes (C. acnes) and eczema complicated by secondary infections with Staphylococcus aureus (S. aureus). Six probiotic strains and various extracts/EOs were evaluated in a large screening to evaluate their potential against both pathogens. Lacticaseibacillus paracasei PCB003 was able to inhibit the growth of both pathogens. For extracts/EOs, Oregano EO had the best antipathogenic effects on both pathogens and did not show any adverse impact on the growth of probiotics, making it suitable for simultaneous use. Using Lactiplantibacillus plantarum PCB011 as a probiotic model, five material formulations were assessed for their suitability to protect probiotic cells within freeze-dried topical patches. Alginate and trehalose (ALG+TRE) and thermoplastic starch (TPS) had the highest probiotic survivability, with ALG+TRE chosen as the final patch material as it was more robust. PCB003 and PCB011 were individually incorporated into the ALG+TRE freeze-dried matrix to form a 6 mm patch; both ALG+TRE (PCB003) and ALG+TRE (PCB011) patches, when used individually, successfully inhibited C. acnes growth by 4.7 and 6.0 mm, respectively, surpassing the performance of commercially available acne patches. The additive effect with 30% Oregano EO further improved pathogen inhibition. For S. aureus, the incorporation of 30% Oregano EO to ALG+TRE (PCB003) increased the size of the inhibition zone more than 10-fold. For C. acnes, the ALG+TRE (PCB003) patch with 30% Oregano EO demonstrated an inhibition zone of 16.3 mm, and the ALG+TRE (PCB011) patch with 30% Oregano EO achieved a 14.3 mm inhibition zone. Genomic analysis confirmed that PCB003 and PCB011 lack antimicrobial resistance determinants, ensuring safety. This study successfully combined probiotics and natural agents to create effective dermatological antipathogenic patches.