Šiugždinienė, Rita

Dirvožemio mikroorganizmai yra ne tik svarbi dirvožemio dalis, bet ir dinamiškas medžiagų transformacijos dirvožemyje šaltinis. Jie atlieka gyvybiškai svarbias ekosistemos funkcijas, tokias kaip skaidymas ir maistinių medžiagų ciklas, ir sudaro simbiotinius ryšius su augalais. Apie tai, kaip skiriasi mikrobiomas naudojant skirtingą ūkininkavimo praktiką augalininkystėje duomenų yra nedaug. Tikėtina, kad mikroorganizmų sudėtis skiriasi taikant ekologinio, intensyvaus ar tausojančio ūkininkavimo praktiką. Šis darbas turėjo du tikslus: pirmiausiai buvo siekiama nustatyti vyraujančios mikrobiotos sudėtį įprastinio ūkininkavimo praktiką (naudojant sėjomainą ir auginant mišrias kultūras) taikančiuose vidurio Lietuvos ūkių dirvožemiuose, o antrasis – nustatyti tiriamos dirvožemio mikrobiotos funkcinių metabolizmo kelių ir atsparumo antibiotikams genetines determinantes. Dirvožemio mėginiai buvo rinkti penkiuose Kėdainių, Radviliškio ir Raseinių rajonų ūkių laukuose, iš pagrindinių augalų šaknų zonos, 5–20 cm sluoksnio, keturiais lauko pakartojimais. Surinkti mėginiai laikyti ant ledo ir tą pačią dieną pristatyti į laboratoriją, kurioje atliktas mėginių apjungimas į vieną bendrą mėginį. DNR išskyrimas atliktas su ZymoBIOMICS®-96 MagBead DNA rinkiniu (JAV). Sekvenavimo bibliotekos paruoštos naudojant Illumina DNA Prep Kit (Illumina, JAV). Paruošti mėginiai buvo sekvenuoti su Illumina NextSeq® 2000 (JAV), atliekant “shotgun” tipo sekoskaitą. Mikroorganizmų sudėtis buvo profiliuota naudojant duomenų bazę Sourmash. Bakterijų, grybelių ir kitų mikroorganizmų identifikavimui naudotos GTDB ir GenBank duomenų bazės. Atsparumo antimikrobinėms medžiagoms genų identifikavimas atliktas DIAMOND sekos palyginimo įrankiu pagal referentines duomenų bazes. Funkcinis bakterijų profiliavimas buvo atliktas naudojant Humann3 duomenų bazę, nustatant pagrindines metabolizmo reakcijas (pathways). Nustatyta, jog dažniausi eukariotiniai mikroorganizmai tirtuose dirvožemiuose buvo Rostrostelium ellipticum, Pedospumella encystans, Spumella vulgaris ir Podosphaera cerasi. Šie grybų ir protistų atstovai sudarė 74 proc. visų eukariotinių mikroorganizmų. Tuo tarpu, prokariotų įvairovė buvo kur kas platesnė. Iš viso identifikuota daugiau nei 150 prokariotų taksonų rūšies lygmenyje. Iš identifikuotų prokariotų rūšių, vyravo bakterijos, tokios kaip Solirubrobacter soli, S. pauli, Nocardioides cavernae, N. gaungzhouensis, N. islandensis ir kitos Nocardioides rūšys, Luteitalea pratensis, Bradyrhizobium algeriense, B. erythroplei ir kitos Bradyrhizobium rūšys, Pedococcus crimeus, Microvirga ossetica, Mycobacterium spp. Funkcinių metabolizmo kelių tyrimai atskleidė nukleotidų ir aminorūgščių sintezės ir skaldymo kelių dominavimą dirvožemio bakterijose, kas rodo aktyvų ir efektyvų dirvožemio mikrobiomą, prisitaikiusį prie pakankamai intensyvaus žemės ūkio naudojimo. Šie keliai atspindėjo stiprų organinio azoto ir anglies perdirbimą, energiją taupančias augimo strategijas ir funkcines savybes, dažniausiai siejamas su augalams naudingais dirvožemio mikroorganizmais. Įprastinio ūkininkavimo ūkių dirvožemio mikrobiota turėjo atsparumo antibiotikams koduojančius genus daugeliui antibiotikų klasių, net ir sintetiniams, gamtoje tiesiogiai neaptinkamiems antibiotikams, tokiems kaip chinolonai. Galima teigti, kad dirvožemio bakterijos prisitaikę ne tik prie natūralios aplinkos, bet yra turėję kontaktą ir su žmogaus sukurtais ir naudojamais antimikrobiniais vaistais, kurie naudojami žmonių ir gyvūnų gydymui.

Prakaito kvapas yra reikšminga higienos ir socialinė problema, susijusi su odos mikrobiotos metaboline veikla. Bakterijos Corynebacterium spp., Staphylococcus hominis ir Staphylococcus epidermidis, bei Cutibacterium (anksčiau Propionibacterium) acnes skaido prakaitą, išskirdamos lakiuosius junginius, atsakingus už nemalonų kvapą. Tai lemia poreikį kurti išmaniąją tekstilę, skirtą mikroorganizmų augimui ir aktyvumui slopinti. Metalų oksidų nanodalelės pasižymi antimikrobinėmis savybėmis, jos gali pažeisti bakterijų ląstelių membranas, sukelti oksidacinį stresą ir sutrikdyti metabolinius procesus. Vienas iš inovatyviausių antimikrobinių dangų formavimo būdų yra žemos temperatūros plazminis garinimas – fizinio garų nusodinimo technologija, leidžianti išgauti tolygias ir patvarias nanodangas be tirpiklių naudojimo. Žemos temperatūros plazmos technologijos taikymas vienu metu užtikrina tekstilės paviršiaus valymą ir funkcionalizavimą, padidina pluošto paviršiaus energiją, pagerina nanoklasterių adheziją ir leidžia suformuoti patvarias, tolygiai pasiskirsčiusias nanodangas, išsaugant tekstilės lankstumą ir sumažinant galimą nanodalelių išsiskyrimą į aplinką. Šio tyrimo tikslas buvo įvertinti cinko oksido (ZnO), volframo oksido (WO₃) ir geležies (III) oksido (Fe₂O₃) nanodalelių, nusodintų ant abiejų medvilninio audinio paviršiaus pusių naudojant plazminį garinimą, antimikrobinį aktyvumą prieš su prakaito kvapu susijusias gramteigiamas bakterijas. Naudojant terpės praskiedimo metodą, atlikti mikrobiologiniai tyrimai įvertinti Corynebacterium auriscanis, Staphylococcus hominis ir meticilinui atspariam S. epidermidis, bei Cutibacterium acnes jautrumą nanodalelėmis padengtam medvilniniam audiniui. Lyginant su kontrole, nustatyta, kad metalų oksidais padengtos nanodangos reikšmingai sumažino tirtų bakterijų augimą, tačiau jų efektyvumas priklausė nuo bakterijų rūšies ir dangos tipo. ZnO 150W danga sumažino C. auriscanis ir S. hominis augimą apie 60 proc., C. acnes – beveik 70 proc., o S. epidermidis net 99 proc. Fe₂O₃ 200W nanodalelėmis dengta danga pasižymėjo stipriu antibakteriniu poveikiu prieš C. acnes ir S. hominis, taip pat S. epidermidis (daugiau nei 90 proc.), o C. auriscanis augimą sumažino tik per pusę (57 proc.). Tuo tarpu, WO₃ 200W, dažnai naudojamas pramonėje, slopino gramteigiamų lazdelių C. auriscanis ir C. acnes, gramteigiamų kokų S. hominis augimą nuo 37 iki 61 proc., kai S. epidermidis (97 proc.) augimą. Tyrimo rezultatai rodo, kad metalo oksidų nanodalelėmis, ypač Fe₂O₃ 200W, dengta medvilnės medžiaga artimiausioje ateityje gali tapti perspektyvia alternatyva prieš prakaitą metabolizuojančias bakterijas.

Microplastics (MPs) are increasingly recognized as environmental contaminants capable of interacting with biological systems. However, their presence in livestock reproductive fluids remains relatively unexplored. In swine artificial insemination, boar semen quality is a key determinant of reproductive efficiency, and spermatozoa are highly susceptible to physicochemical stressors present in their surrounding microenvironment. Particulate contaminants such as MPs may therefore represent an overlooked factor relevant to semen quality. The present study investigated the occurrence, polymer composition, and size distribution of MPs in undiluted boar semen using μFTIR spectroscopy. In addition, exploratory analyses were conducted to evaluate potential associations between MPs and semen motility parameters assessed using computer-assisted sperm analysis (CASA) system, as well as bacterial load and antimicrobial susceptibility profiles of bacteria isolates. MPs were detected in all analyzed semen samples (n = 12), with concentration median (min–max) 9.58 (0.48–19.00) MPs/ml. Considerable variability was observed between individual boars and between the two participating breeding facilities. Polyethylene was the most frequently identified polymer. Exploratory analyses revealed that higher concentrations of specific polymers, particularly polyethylene and polyester, were associated with differences in sperm velocity distribution, characterized by a lower proportion of rapidly motile spermatozoa and a higher proportion of spermatozoa with slow velocity. Although there was no association between MPs levels and total bacterial counts, limited statistically significant associations were identified between the antimicrobial susceptibility profiles of the most frequently isolated bacterial species and specific MPs polymer types. These findings suggest that MPs may be related to sperm function and bacteria–antibiotic interactions within the seminal microenvironment. This study provides, to our knowledge, the first evidence of MPs in boar semen and identifies MPs as a potential environmental contamination factor relevant to semen quality.

Malassezia pachydermatis is a commensal microorganism found on the skin and mucous membranes of healthy animals [1]. However, it is responsible for Malassezia dermatitis, especially in dogs with underlying conditions, as these yeasts proliferate and induce disease when the normal skin balance is disrupted by factors such as allergies, endocrine disorders, or other skin diseases [2]. Although M. pachydermatis is usually treatable, repeated or improper treatment may lead to resistance to multiple azoles (e.g., fluconazole, itraconazole, ketoconazole) [3]. It was reported that different metal nanoparticles exert antifungal effects on M. pachydermatis through mechanisms such as ion release, oxidative stress induction, membrane disruption, and interference with virulence factors, with zinc oxide and silver nanoparticles showing the most promising balance of efficacy and clinical applicability [4, 5]. This study aimed to evaluate the antimicrobial activity of cotton material functionalized with metal- and metal oxide-nanoparticles against the yeast M. pachydermatis. The Malassezia species was determined using MALDI-TOF mass spectrometry. Metal oxides (CuO, WO3, AgO, Fe2O3, ZnO, SiO2, CeO2), along with Mg and Fe nanoparticles (NPs), were deposited on one side of the cotton material using lowtemperature plasma technology in a pure oxygen or argon atmosphere. To assess the antimicrobial activity of metals and metal oxide nanoparticles against clinical canine isolates, the broth microdilution method was employed. The strongest inhibitory effect was observed with CuO and AgO, which suppressed approximately 90% of yeast growth. Moderate activity was recorded for Fe2O3, ZnO, CeO2, and Mg-enhanced cotton materials, with inhibition ranging from 55% to 69%. The weakest antifungal activity was observed by WO3 and Fe metal nanoparticles (from 15% to 38%), whereas SiO2 activated the growth of M. pachydermatis by 13%. The research results are promising due to the strong performance of CuO and AgO metal nanoparticles embedded in cotton textile; however, further studies are needed to evaluate the in vivo safety and efficacy of the nanoparticles.

Background: Hedgehogs are small nocturnal insectivorous mammals. They are frequently found in agricultural land, parks, home gardens, where they encounter humans and domestic animals. Wild hedgehogs are one of the most common mammals that get into wildlife rescue centres (1). Nowadays the One Health principle is getting a lot of attention, which is defined as the assumption that human health is strongly connected with animal health and the environment. Its focus is food safety, zoonotic diseases and antimicrobial resistance (2). Because of the close contact between hedgehogs and humans, it is crucial to research the health of wild hedgehogs and figure out if there is a risk of zoonoses and spread of antibioticresistant bacteria. Aims: To assess the health of Northern white-breasted hedgehogs (Erinaceus roumanicus) in Lithuanian University of Health Sciences (LUHS) Wildlife Rescue Centre and test if they carry any antibiotic-resistant bacteria. Methods: The hedgehog health was assessed by using a specific hedgehog health protocol that was filled out by veterinarians of LUHS Wildlife Rescue Centre. The veterinarians also took bacteriological samples from the hedgehog’s mouth and/or feces, wounds. The samples were then tested in the Lithuanian University of Health Sciences, Veterinary academy, Faculty of Veterinary Medicine, Department of Anatomy and Physiology, Microbiological Research Laboratory. Results: 10 hedgehogs were sampled, of which 7 were adults and 3 hoglets (too young to be independent), 5 male and 5 female. The reason for rehabilitation for adults was because 43% had serious wounds, 29% had some kind of trauma (concussion, broken bones) and 28% had severe respiratory issues. Worth to mention that 70% of adult hedgehogs had some kind of respiratory issues – difficulty breathing, bronchopneumonia, lung crepitation. Death was an outcome for 80% of the tested hedgehogs and 20% were released to the wild. Bacteriological samples were taken from all the hedgehogs: 10 from the mouth, 4 from wounds and 3 from feces. A total of 20 bacterial isolates were identified. Most common identified species were Escherichia coli, Staphylococcus simulans, Staphylococcus sciuri, Klebsiella oxytoca, Aeromonas hydrophila, etc. Antimicrobial susceptibility tests were performed for 5 bacteria that were extracted from the wounds to help with treatment. All tested bacteria were resistant to at least one antibiotic, and one bacterium (Escherichia coli) was multi-resistant (resistant to >3 antibiotics). Resistance was confirmed to antibiotics like amoxicillin, enrofloxacin, streptomycin, tetracycline, gentamicin, etc. The antimicrobial susceptibility tests were interpreted using EUCAST (3). Conclusion: Overall, according to the data of this study, it is apparent that wild hedgehogs in Lithuania deal with a variety of different illnesses. The bacteria that were identified were resistant to some of the most used antibiotics in both human and animal medicine and given the hedgehog’s urban distribution, they could represent a risk factor for the acquisition of resistant bacteria by humans and domestic animals. Further research is needed to examine a larger sample of wild hedgehogs and to evaluate their health status and potential risk to humans.

Introduction: Colic remains a major cause of emergency intervention in horses, and feeding practices are a critical component of risk management. Freshly cut, semi-dried grass is often considered a convenient feed source, yet early fermentation processes may predispose horses to gastrointestinal disturbances. This study investigated microbiological, physicochemical, and sensory changes in grass clippings during natural drying to identify factors contributing to colic development. Methods: Grass samples were collected near Stable X during the seasonal peak of grass-related colic. The grass samples were collected at three time points (0 h, after 12 h and 24 h of fermentation), and three independent replicates were obtained at each time point, resulting in a total n=9. Microbiological evaluation was performed using Columbia Blood Agar under anaerobic conditions, followed by Gram staining. Feed quality assessment included dry matter (DM), pH, and concentrations of nitrogen, phosphorus, and calcium. Organoleptic characteristics were also documented. Clinical colic cases recorded in the LSMU Large Animal Clinic during the same period were reviewed to support laboratory findings. Results: Across all replicates, Clostridium botulinum was not detected. Instead, Actinomyces spp. and nonspecific Gram-positive rods proliferated consistently, with the highest bacterial load in the 24-hour samples. DM displayed a uniform pattern: a slight increase at 12 hours, followed by a statistically significant decline at 24 hours (mean decrease 26.5%, p 0.05), indicating active microbial fermentation. Nitrogen and phosphorus increased, while calcium decreased; pH remained acidic. Sensory evaluation revealed progressive heating, darkening, and development of spoilage odour. Clinical data demonstrated recurrent episodes of gaseous distension and reduced intestinal motility, consistent with laboratory findings. Conclusions: The results confirmed that freshly cut grass undergoes rapid, reproducible fermentation within 24 hours, producing conditions that predispose horses to fermentation-related colic. Semi-dried grass clippings represent a consistent feeding risk and should be avoided. Consider it as a hypothesis and expand the studies.

The oral microbiome of apex predators such as grey wolves (Canis lupus) is colonised by complex microbial communities and plays a crucial role in the health of wild mammals, but remains poorly understood. In this study, a single pooled sample mixed from oral samples of 17 wolves (Canis lupus) hunted in Lithuania was investigated for the determination of a variety of oral microbiota, providing the first metagenomic insight into wolf oral microbiomes in Baltic countries. The aim of this study was to identify the zoonotic and antimicrobial resistance potential of the oral microbiota. The results revealed diverse microbiomes associated with periodontal health as well as microbiomes related to the environment. Unique microbial taxa potentially reflect the nutritional and ecological interactions of carnivores. Shotgun metagenomic sequencing yielded a total of 18,726,406 raw reads, and following quality trimming and filtering, 86.01% of these (16,106,613) were retained. Among the total reads, 45.15% (8,455,255) were identified as host-derived and were removed. The most common oral bacterial genera were Pseudomonas (50%) and Psychrobacter (22.6%). Metagenomic reads for zoonotic pathogens, including Salmonella, Mycobacterium spp., Yersinia, Coxiella burnetii, Corynebacterium pseudotuberculosis, and others, were also detected, suggesting that grey wolves are potential natural reservoirs of zoonotic infections. Genes encoding antimicrobial resistance to many classes of antibiotics were also detected. This research contributes to understanding wolf dietary habits, oral health, the carriage and possible risk of transmitting AMR, and social interactions.

Nanofabrics, also known as nanotextiles or smart textiles, are a promising solution for combating infections caused by antimicrobial-resistant pathogens, offering an alternative to antibiotics. This study focuses on enhancing the antimicrobial properties of cotton material by depositing WO3 nanoparticles on the textile surface using low-temperature plasma sputtering technology in a pure oxygen atmosphere. The properties of the deposited WO3 nanoparticles were evaluated using Scanning Electron Microscopy (SEM) combined with Energy-Dispersive Spectroscopy (EDS) and X-ray Photoelectron Spectroscopy (XPS). The developed antibacterial textiles were tested against 18 microbial strains, including both Gram-positive and Gram-negative bacteria, as well as fungi, demonstrating high antimicrobial efficacy against most. The growth of bacteria Pasteurella multocida was promoted following exposure to WO3 nanoparticles, while the tested material showed no effectiveness against the fungus Candida albicans REF10231. The cytotoxic and genotoxic properties of the WO3 nanoparticle-modified textile were assessed in vitro utilizing human endothelial HUVEC cells. No evidence of short-term (24-hour exposure) or long-term (72-hour exposure) toxicity was detected in textiles subjected to treatment with WO3 nanoparticles. However, for practical use, toxicity studies are essential to assess the safe application of these materials in clinical settings. This research highlights the potential of WO3 nanoparticle-modified textiles in addressing the global challenge of microbial infections while offering a sustainable and eco-friendly alternative to conventional antimicrobial treatments.

Introduction. Skin infections are an increasing concern in both human and veterinary medicine due to factors such as antimicrobial resistance, lifestyle changes, and hygiene habits. The frequent and inappropriate use of systemic antibiotics for superficial skin infections has led to multidrug-resistant pathogens, complicating treatment [1]. This highlights the need for alternative therapies, such as topical antiseptics, to reduce antibiotic use and resistance development. Objective. This study aimed to evaluate the in vitro antimicrobial activity of a chitosan gels containing chlorhexidine against Gram-positive and Gram-negative bacteria. Methods. The gel’s antimicrobial properties were assessed in vitro using the agar diffusion method on Mueller-Hinton agar [2]. Tested organisms included reference strains of Staphylococcus aureus (ATCC 25923), Enterococcus faecalis (ATCC 29212), Escherichia coli (ATCC 25922), and Pseudomonas aeruginosa (ATCC 27853), along with wild strains of the same species. Results. The antimicrobial effect of the gels was not dependent on chlorhexidine concentration but was influenced by chitosan content. The 1% chitosan gel showed the strongest inhibitory effect on both reference and wild strains. The results emphasized the importance of testing both strain types, as wild strains were generally more resistant than reference strains. This suggests chitosan boosts chlorhexidine’s antimicrobial effect and shows potential for use in skin and wound antisepsis in veterinary medicine. Conclusions. The study confirmed the synergistic action of chlorhexidine and chitosan, with stronger efficacy against Gram-positive bacteria. Further preclinical trials are planned, and it is expected that chitosan, combined with chlorhexidine, will not only enhance antimicrobial activity but also aid wound healing in damaged tissues.

Aquaculture is a rapidly growing food production sector [1]. It offers potential for food production worldwide, but the rapid growth of aquaculture has raised concerns about the quality and safety of the products, particularly because of antimicrobial resistance and heavy metals [2, 3]. The aim of this study was to investigate the situation of antimicrobial resistance of bacteri4al isolates from an open fishpond. Bacteria from fish caught in natural surrounding water bodies and their resistance to antibiotics were also examined for comparison. Indicator bacteria and multi-resistant bacteria from two different fish species – Tench (Tinca tinca) and Roach (Rutilus rutilus) – were investigated. The results showed that the composition of Aeromonas and their susceptibility to different antimicrobials were similar in fish from the pond and the lake into which the pond water drains. Meanwhile, the composition of fish bacteria and resistance patterns from the lake into which the pond water does not drain, differ. An analogous situation was found with regard to multi-resistant bacterial isolates. The studies allow us to conclude that in fish cultivated in open ponds and in water receiving inflow from ponds enters, there are multi-resistant bacteria to antibiotics, which may affect the quality of production on the basis of the “One Health” concept.