Total transcriptome response for tyrosol exposure in Aspergillus nidulans.

Although tyrosol is a quorum-sensing molecule of Candida species, it has antifungal activity at supraphysiological concentrations. Here, we studied the effect of tyrosol on the physiology and genome-wide transcription of Aspergillus nidulans to gain insight into the background of the antifungal activity of this compound. Tyrosol efficiently reduced germination of conidia and the growth on various carbon sources at a concentration of 35 mM. The growth inhibition was fungistatic rather than fungicide on glucose and was accompanied with downregulation of 2199 genes related to e.g. mitotic cell cycle, glycolysis, nitrate and sulphate assimilation, chitin biosynthesis, and upregulation of 2250 genes involved in e.g. lipid catabolism, amino acid degradation and lactose utilization. Tyrosol treatment also upregulated genes encoding glutathione-S-transferases (GSTs), increased specific GST activities and the glutathione (GSH) content of the cells, suggesting that A. nidulans can detoxify tyrosol in a GSH-dependent manner even though this process was weak. Tyrosol did not induce oxidative stress in this species, but upregulated "response to nutrient levels", "regulation of nitrogen utilization", "carbon catabolite activation of transcription" and "autophagy" genes. Tyrosol may have disturbed the regulation and orchestration of cellular metabolism, leading to impaired use of nutrients, which resulted in growth reduction.

Epidemiology, clinical characteristics, outcome and biofilm forming properties in candidaemia: A single-centre retrospective 4-year analysis from Hungary.

BACKGROUND: Candidaemia is a life-threatening disease that is associated with high mortality, especially in intensive care units (ICUs). The number of comprehensive studies dealing with the epidemiologic characteristics of biofilm-related properties is limited. OBJECTIVE: This study evaluated the clinical characteristics of candidaemia, to assess the biofilm-forming properties of isolates, and to identify the risk factors of mortality. PATIENTS AND METHODS: A total of 149 candidaemia episodes from the University of Debrecen, Clinical Centre, between January 2020 and December 2023 were investigated retrospectively. The susceptibility of Candida isolates to fluconazole, amphotericin B, anidulafungin, caspofungin, and micafungin was evaluated and compared to the susceptibility of 1-day-old biofilms. Multivariate logistic regression analysis was applied to identify the independent predictors of 30-day mortality rate. RESULTS: The most common Candida species was Candida albicans (41%), followed by C. parapsilosis (20%), C. glabrata (14%), C. tropicalis (13%), rare Candida species (7%), and C. krusei (5%). Sixty-six percent of Candida isolates were biofilm formers and 44% had high metabolic activity. The 30-day mortality rate was 52%, which was higher in ICUs (65%). The logistic regression analysis revealed several factors significantly influencing mortality including ICU admission (odds ratio [OR] 2.99, 95% confidence interval [CI] 1.17-8.04, p = 0.025), fluconazole treatment (OR 4.12, 95% CI 1.62-11.42, p = .004), and pneumonia (OR 0.261, 95% CI 0.1-0.67, p = .006). CONCLUSIONS: This comprehensive analysis supports the better characterisation of candidaemia in healthcare settings, which ultimately may reduce mortality among patients.

Comparative transcriptional analysis of Candida auris biofilms following farnesol and tyrosol treatment.

Candida auris is frequently associated with biofilm-related invasive infections. The resistant profile of these biofilms necessitates innovative therapeutic options, where quorum sensing may be a potential target. Farnesol and tyrosol are two fungal quorum-sensing molecules with antifungal effects at supraphysiological concentrations. Here, we performed genome-wide transcript profiling with C. auris biofilms following farnesol or tyrosol exposure using transcriptome sequencing (RNA-Seq). Since transition metals play a central role in fungal virulence and biofilm formation, levels of intracellular calcium, magnesium, and iron were determined following farnesol or tyrosol treatment using inductively coupled plasma optical emission spectrometry. Farnesol caused an 89.9% and 73.8% significant reduction in the calcium and magnesium content, respectively, whereas tyrosol resulted in 82.6%, 76.6%, and 81.2% decrease in the calcium, magnesium, and iron content, respectively, compared to the control. Genes involved in biofilm events, glycolysis, ergosterol biosynthesis, fatty acid oxidation, iron metabolism, and autophagy were primarily affected in treated cells. To prove ergosterol quorum-sensing molecule interactions, microdilution-based susceptibility testing was performed, where the complexation of farnesol, but not tyrosol, with ergosterol was impeded in the presence of exogenous ergosterol, resulting in a minimum inhibitory concentration increase in the quorum-sensing molecules. This study revealed several farnesol- and tyrosol-specific responses, which will contribute to the development of alternative therapies against C. auris biofilms. IMPORTANCE: Candida auris is a multidrug-resistant fungal pathogen, which is frequently associated with biofilm-related infections. Candida-derived quorum-sensing molecules (farnesol and tyrosol) play a pivotal role in the regulation of fungal morphogenesis and biofilm development. Furthermore, they may have remarkable anti-biofilm effects, especially at supraphysiological concentrations. Innovative therapeutic approaches interfering with quorum sensing may be a promising future strategy against C. auris biofilms; however, limited data are currently available concerning farnesol-induced and tyrosol-related molecular effects in C. auris. Here, we detected several genes involved in biofilm events, glycolysis, ergosterol biosynthesis, fatty acid oxidation, iron metabolism, and autophagy, which were primarily influenced following farnesol or tyrosol exposure. Moreover, calcium, magnesium, and iron homeostasis were also significantly affected. These results reveal those molecular and physiological events, which may support the development of novel therapeutic approaches against C. auris biofilms.

Genomic epidemiology of antifungal resistance in human and avian isolates of Candida albicans: a pilot study from the One Health perspective.

Stress-induced genomic changes in Candida albicans contribute to the adaptation of this species to various environmental conditions. Variations of the genome composition of animal-origin C. albicans strains are largely unexplored and drug resistance or other selective pressures driving the evolution of these yeasts remained an intriguing question. Comparative genome analysis was carried out to uncover chromosomal aneuploidies and regions with loss of heterozygosity (LOH), two mechanisms that manage genome plasticity. We detected aneuploidy only in human isolates. Bird-derived isolates showed LOH in genes commonly associated with antifungal drug resistance similar to human isolates. Our study suggests that environmental fungicide usage might exert selective pressure on C. albicans infecting animals, thus contributing to the spread of potentially resistant strains between different hosts.

Unveiling the Hungarian landscape of laboratory and clinical management capacities for invasive fungal infections: navigating the frontlines against fungal menaces.

Background: Antifungal diagnostic capacity has been documented in various countries, there is a lack of comprehensive research on clinical mycology diagnostics and treatment in Hungary. Methods: We conducted an online survey encompassing questions that explored various aspects of the mycology diagnostic and antifungal therapy-related information. The survey aimed to gather details about institutional profiles, perceptions of invasive fungal infections (IFIs), and access to microscopy, culture, serology, antigen detection, molecular testing, and therapeutic drug monitoring. Results: As of May 2023, a total of 17 institutions responded to the questionnaire. Seven participants categorized the institutional incidence of IFI as 'very low', four as 'low', and six as 'mild'. The majority of centers identified Candida spp. (94%) and Aspergillus spp. (82%) as the most prevalent fungal pathogens. Nearly half of the laboratories (47%) reported using matrix-assisted laser desorption/ionization-time of flight mass spectrometry for identification. All institutions had access to microscopy and culture-based diagnostic approaches. A significant number of centers had access to antigen detection (71%) and various molecular assays (59%). Regarding antifungal agents, all reporting sites used at least one triazole, with voriconazole (77%) being the most common mold-active azole. Furthermore, 71% of the centers applied at least one formulation of amphotericin B, and 65% to one echinocandin. However, only 18% of the centers used 5-flucytosine. Conclusion: Resource availability for diagnosing and treating IFI in Hungary varies across hospitals based on location. Surveys help identify gaps and limitations in this area. To address these challenges, interregional cooperation within Hungary could be a facilitating strategy.

METHODS: We did an online survey with questions about how hospitals in Hungary handle fungal infections. We wanted to know about the hospitals' characteristics, how they see these infections, and what tools they use for diagnosis and treatment. RESULTS: As of May 2023, we got responses from 17 hospitals. Some said they hardly ever see these infections, while others said they see them a bit more. Most hospitals found Candida and Aspergillus as the most common fungal culprits. Many used a tool called MALDI-TOF MS for identification. All of them had ways to look at samples under a microscope and grow them in a dish. Many hospitals had tests to look for certain things in the blood (71%), and they also used different genetic tests (59%). When it came to medicines, they all had at least one kind of medicine called a triazole, with voriconazole being the most common one. They also had amphotericin B and echinocandins. But only a few had a medicine called 5-flucytosine. CONCLUSION: Hospitals in Hungary differ in how they handle fungal infections. Doing surveys like this can help find problems and limits. To fix these issues, hospitals in different parts of Hungary can work together.

Exploring how Hungary deals with serious fungal infections: facing fungal threats head-on Background: While various countries have looked into their ability to diagnose fungal infections, there hasn't been a comprehensive study on how Hungary deals with diagnosing and treating these infections.

Total transcriptome analysis of Candida auris planktonic cells exposed to tyrosol.

Tyrosol, a secondary metabolite of Candida species, regulates fungal morphogenesis, and its application may represent a novel innovative therapy against emerging multi-resistant fungal superbug such as Candida auris. In the current study, the effects of tyrosol on growth, redox homeostasis, intracellular microelement contents and activities of virulence-related enzymes released by C. auris were examined. To gain further information about the effect of tyrosol exposure, we revealed gene transcriptional changes using total transcriptome sequencing (RNA-Seq). At a concentration of 15 mM, tyrosol significantly decrease the growth of fungal cells within 2 h of its addition (5.6 × 107±1.2 × 107 and 2.5 × 107±0.6 × 107 colony forming unit/mL for control and tyrosol-treated cells, respectively). Furthermore, it enhanced the release of reactive oxygen species as confirmed by a dichlorofluorescein (DCF) assay (7.3 ± 1.8 [nmol DCF (OD640)-1] versus 16.8 ± 3.9 [nmol DCF (OD640)-1]), which was coincided with elevated superoxide dismutase, catalase and glutathione peroxidase activities. Tyrosol exerted in a 37%, 25%, 34% and 55% decrease in intracellular manganese, iron, zinc and copper contents, respectively, compared to control cells. The tyrosol treatment led to a 142 and 108 differentially transcripted genes with at least a 1.5-fold increase or decrease in transcription, respectively. Genes related to iron and fatty acid metabolism as well as nucleic acid synthesis were down-regulated, whereas those related to the antioxidative defence, adhesion and oxoacid metabolic processes were up-regulated. This study shows that tyrosol significantly influences growth, intracellular physiological processes and gene transcription in C. auris, which could highly support the development of novel treatment approaches against this important pathogen.

In Vitro Killing Activities of Anidulafungin and Micafungin with and without Nikkomycin Z against Four Candida auris Clades.

Candida auris is a multidrug-resistant pathogen against which echinocandins are the drug of choice. However, information on how the chitin synthase inhibitor nikkomycin Z influences the killing activities of echinocandins against C. auris is currently lacking. We determined the killing activities of anidulafungin and micafungin (0.25, 1, 8, 16 and 32 mg/L each) with and without nikkomycin Z (8 mg/L) against 15 isolates representing four C. auris clades (South Asian n = 5; East Asian n = 3; South African n = 3; South American n = 4, two of which were of environmental origin). Two and one isolates from the South Asian clade harbored mutations in the hot-spot 1 (S639Y and S639P) and 2 (R1354H) regions of the FKS1 gene, respectively. The anidulafungin, micafungin and nikkomycin Z MIC ranges were 0.015-4, 0.03-4 and 2->16 mg/L, respectively. Anidulafungin and micafungin alone exerted weak fungistatic activity against wild-type isolates and the isolate with a mutation in the hot-spot 2 region of FKS1 but was ineffective against the isolates with a mutation in the hot-spot 1 region. The nikkomycin Z killing curves were always similar to their respective controls. Twenty-two of sixty (36.7%) anidulafungin plus nikkomycin Z and twenty-four of sixty (40%) micafungin plus nikkomycin Z combinations produced at least 100-fold decreases in the CFUs (synergy), with a 41.7% and 20% fungicidal effect, respectively, against wild-type isolates. Antagonism was never observed. Similar results were found with the isolate with a mutation in hot-spot 2 of FKS1, but the combinations were ineffective against the two isolates with prominent mutations in hot-spot 1 of FKS1. The simultaneous inhibition of ß-1,3 glucan and chitin synthases in wild-type C. auris isolates produced significantly greater killing rates than either drug alone. Further studies are warranted to verify the clinical efficacy of echinocandin plus nikkomycin Z combinations against echinocandin susceptible C. auris isolates.

High-Throughput Sequencing Analysis of the Changes in the Salivary Microbiota of Hungarian Young and Adult Subpopulation by an Anthocyanin Chewing Gum and Toothbrush Change.

The sour cherry contains anthocyanins, which have bactericide action against some oral bacteria (Klebsiella pneumoniae, Pseudomonas aeruginosa). Sour cherry also has antibiofilm action against Streptococcus mutans, Candida albicans, and Fusobacterium nucleatum. Our earlier research proved that chewing sour cherry anthocyanin gum significantly reduces the amount of human salivary alpha-amylase and Streptococcus mutans levels. The microbiota of a toothbrush affects oral health and regular toothbrush change is recommended. A total of 20 healthy participants were selected for the study. We analysed saliva samples with 16S rRNA sequencing to investigate the effect of 2 weeks (daily three times, after main meals) of chewing sour cherry anthocyanin gum-supplemented by toothbrush change in half of our case-control study cohort-after scaling on human oral microbiota. A more stable and diverse microbiome could be observed after scaling by the anthocyanin gum. Significant differences between groups (NBR: not toothbrush changing; BR: toothbrush changing) were evaluated by log2 proportion analysis of the most abundant family and genera. The analysis showed that lower level of some Gram-negative anaerobic (Prevotella melaninogenica, Porphyromonas pasteri, Fusobacterium nucleatum subsp. vincentii) and Gram-positive (Rothia mucilaginosa) bacteria could be observed in the case group (BR), accompanied by build-up of health-associated Streptococcal network connections.

The In Vitro Activity of Fluconazole, Amphotericin B and Echinocandins Against Cyberlindnera fabianii Planktonic Cells and Biofilms.

Until recently, little was known about the susceptibility pattern of Cyberlindnera fabianii (Cy. fabianii) planktonic cells and biofilms regarding the most frequently administered systemic antifungals, despite the high mortality rate and its potential role in catheter-related infections. In the current study, the activity of fluconazole, amphotericin B and echinocandins (anidulafungin, caspofungin and micafungin) was determined against planktonic and sessile cells of Cy. fabianii clinical isolates (n = 8). Planktonic minimum inhibitory concentrations (MICs) ranged from 1 to 2, from 0.25 to 1, from 0.015 to 0.06, from 0.03 to 0.12 and from 0.25 to 0.5 mg/l for fluconazole, amphotericin B, anidulafungin, caspofungin and micafungin, respectively. One-day-old biofilms were highly resistant to fluconazole (MIC ranged from 512 to > 512) compared to planktonic counterparts, but not to amphotericin B (MIC ranged from 0.25 to 2 mg/l) and echinocandins (MIC ranged from 0.06 to 2 mg/l). Based on the calculated planktonic killing rates, the highest activity was observed in the case of anidulafungin (k values ranged from 0.37 to 2.09), while micafungin, caspofungin, amphotericin B and fluconazole exerted 0.46-1.47, 0.14-0.86, -0.03 to 2.08 and -0.15 to 0.09 killing rate value ranges, respectively. The obtained in vitro planktonic and sessile susceptibility patterns suggest that echinocandins and amphotericin B may be the most reliable treatment option for the treatment of Cy. fabianii infections.

Synergistic Interaction of Caspofungin Combined with Posaconazole against FKS Wild-Type and Mutant Candida auris Planktonic Cells and Biofilms.

Candida auris is a potential multidrug-resistant pathogen able to cause biofilm-associated outbreaks, where frequently indwelling devices are the source of infections. The number of effective therapies is limited; thus, new, even-combination-based strategies are needed. Therefore, the in vitro efficacy of caspofungin with posaconazole against FKS wild-type and mutant Candida auris isolates was determined. The interactions were assessed utilizing the fractional inhibitory concentration indices (FICIs), the Bliss model, and a LIVE/DEAD assay. Planktonic minimum inhibitory concentrations (pMICs) for the caspofungin-posaconazole combination showed a 4- to 256-fold and a 2- to 512-fold decrease compared to caspofungin and posaconazole alone, respectively. Sessile minimum inhibitory concentrations (sMICs) for caspofungin and posaconazole in combination showed an 8- to 128-fold and a 4- to 512-fold decrease, respectively. The combination showed synergy, especially against biofilms (FICIs were 0.033-0.375 and 0.091-0.5, and Bliss cumulative synergy volumes were 6.96 and 32.39 for echinocandin-susceptible and -resistant isolates, respectively). The caspofungin-exposed (4 mg/L) C. auris biofilms exhibited increased cell death in the presence of posaconazole (0.03 mg/L) compared to untreated, caspofungin-exposed and posaconazole-treated biofilms. Despite the favorable effect of caspofungin with posaconazole, in vivo studies are needed to confirm the therapeutic potential of this combination in C. auris-associated infections.

Physiological and transcriptional profiling of surfactin exerted antifungal effect against Candida albicans.

Given the risk of Candida albicans overgrowth in the gut, novel complementary therapies should be developed to reduce fungal dominancy. This study highlights the antifungal characteristics of a Bacillus subtilis-derived secondary metabolite, surfactin with high potential against C. albicans. Surfactin inhibited the growth of C. albicans following a 1-hour exposure, in addition to reduced adhesion and morphogenesis. Specifically, surfactin did not affect the level of reactive oxygen species but increased the level of reduced glutathione. Surprisingly, ethanol production was increased following 2 h of surfactin exposure. Surfactin treatment caused a significant reduction in intracellular iron, manganese and zinc content compared to control cells, whereas the level of copper was not affected. Alongside these physiological properties, surfactin also enhanced fluconazole efficacy. To gain detailed insights into the surfactin-related effects on C. albicans, genome-wide gene transcription analysis was performed. Surfactin treatment resulted in 1390 differentially expressed genes according to total transcriptome sequencing (RNA-Seq). Of these, 773 and 617 genes with at least a 1.5-fold increase or decrease in transcription, respectively, were selected for detailed investigation. Several genes involved in morphogenesis or related to metabolism (e.g., glycolysis, ethanol and fatty acid biosynthesis) were down-regulated. Moreover, surfactin decreased the expression of ERG1, ERG3, ERG9, ERG10 and ERG11 involved in ergosterol synthesis, whereas genes associated with ribosome biogenesis and iron metabolism and drug transport-related genes were up-regulated. Our data demonstrate that surfactin significantly influences the physiology and gene transcription of C. albicans, and could contribute to the development of a novel innovative complementary therapy.

Investigation of the Role and Effectiveness of Chitosan Coating on Probiotic Microcapsules.

Microencapsulation and coating are preferred methods to increase the viability of the probiotic strains. The effect of microencapsulation technologies and materials used as microcapsule cores on viability is being investigated during development. In the present study, chitosan-coated and Eudragit L100-55-coated alginate microspheres were produced to encapsulate Lactobacillus plantarum probiotic bacteria. After the heat loading and simulated gastrointestinal juice dissolution study, the differences in viability were compared based on the CFU/mL values of the samples. The kinetics of the bacterial release and the ratio of the released live/dead cells of Lactobacillus plantarum were examined by flow cytometry. In all cases, we found that the CFU value for the chitosan-coated samples was virtually zero. The ratio of live/dead cells in the 120 min samples was significantly reduced to less than 20% for chitosan, while it was nearly 90% in the uncoated and Eudragit L100-55-coated samples. In the case of chitosan, based on some published MIC values and the amount of chitosan coating determined in the present study, we concluded the reason for our results. It was the first time to determine the amount of the released chitosan coat of the dried microcapsule, which reached the MIC value during the dissolution studies.

Combined Release of Antiseptic and Antibiotic Drugs from Visible Light Polymerized Biodegradable Nanocomposite Hydrogels for Periodontitis Treatment.

The in situ application of the combination of different types of drugs revolutionized the area of periodontal therapy. The purpose of this study was to develop nanocomposite hydrogel (NCHG) as a pH-sensitive drug delivery system. To achieve local applicability of the NCHG in dental practice, routinely used blue-light photopolymerization was chosen for preparation. The setting time was 60 s, which resulted in stable hydrogel structures. Universal Britton-Robinson buffer solutions were used to investigate the effect of pH in the range 4-12 on the release of drugs that can be used in the periodontal pocket. Metronidazole was released from the NCHGs within 12 h, but chlorhexidine showed a much longer elution time with strong pH dependence, which lasted more than 7 days as it was corroborated by the bactericidal effect. The biocompatibility of the NCHGs was proven by Alamar-blue test and the effectiveness of drug release in the acidic medium was also demonstrated. This fast photo-polymerizable NCHG can help to establish a locally applicable combined drug delivery system which can be loaded with the required amount of medicines and can reduce the side effects of the systemic use of drugs that have to be used in high doses to reach an ideal concentration locally.

In Vivo Efficacy of Amphotericin B against Four Candida auris Clades.

Candida auris is a multidrug-resistant fungus against which in some clinical situations amphotericin B (AMB) remains the alternative or first line drug. We compared daily 1 mg/kg of AMB efficacy in a neutropenic murine bloodstream infection model against 10 isolates representing four C. auris clades (South Asian n = 2; East Asian n = 2; South African n = 2; South American n = 4; two of which were of environmental origin). Five days of AMB treatment significantly increased the survival rates in mice infected with isolates of the East Asian clade, and 1 isolate each from the South African and South American clades (originated from bloodstream), but not in mice infected with the South Asian and 2 environmental isolates from the South American clades. AMB treatment decreased the fungal burden in mice infected with the 2 isolates each from East Asian and South African, and 1 out of 2 bloodstream isolates from South American clades in the hearts (p < 0.01), kidneys (p < 0.01) and brain (p < 0.05). AMB treatment, regardless of clades, significantly decreased colony forming units in the urine at day 3. However, histopathological examination in AMB-treated mice revealed large aggregates of yeast cells in the kidneys and hearts, and focal lesions in the cerebra and cerebelli, regardless of precise C. auris clade. Our clade-specific data confirm that the efficacy of AMB against C. auris is weak, explaining the therapeutic failures in clinical situations. Our results draw attention to the necessity to maximize the killing at the start of treatment to avoid later complications in the heart and central nervous system.

Heme Oxygenase-1 (HMX1) Loss of Function Increases the In-Host Fitness of the Saccharomyces 'boulardii' Probiotic Yeast in a Mouse Fungemia Model.

The use of yeast-containing probiotics is on the rise; however, these products occasionally cause fungal infections and possibly even fungemia among susceptible probiotic-treated patients. The incidence of such cases is probably underestimated, which is why it is important to delve deeper into the pathomechanism and the adaptive features of S. 'boulardii'. Here in this study, the potential role of the gene heme oxygenase-1 (HMX1) in probiotic yeast bloodstream-derived infections was studied by generating marker-free HMX1 deletion mutants with CRISPR/Cas9 technology from both commercial and clinical S. 'boulardii' isolates. The six commercial and clinical yeasts used here represented closely related but different genetic backgrounds as revealed by comparative genomic analysis. We compared the wild-type isolates against deletion mutants for their tolerance of iron starvation, hemolytic activity, as well as kidney burden in immunosuppressed BALB/c mice after lateral tail vein injection. Our results reveal that the lack of HMX1 in S. 'boulardii' significantly (p < 0.0001) increases the kidney burden of the mice in most genetic backgrounds, while at the same time causes decreased growth in iron-deprived media in vitro. These findings indicate that even a single-gene loss-of-function mutation can, surprisingly, cause elevated fitness in the host during an opportunistic systemic infection. Our findings indicate that the safety assessment of S. 'boulardii' strains should not only take strain-to-strain variation into account, but also avoid extrapolating in vitro results to in vivo virulence factor determination.

KI and WU Polyomaviruses: Seroprevalence Study and DNA Prevalence in SARS-CoV-2 RNA Positive and Negative Respiratory Samples.

The aim of this work was to study the possible co-infection of KI and WU polyomavirus (KIPyV and WUPyV, respectively) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in respiratory samples and to detect the seroprevalence of KIPyV and WUPyV. A total of 1030 nasopharyngeal samples were analyzed from SARS-CoV-2 RNA positive (n = 680) and negative (n = 350) adults and children (age: 1 day to 94.2 years) collected from August 2020 to October 2021. KIPyV DNA was detected in two SARS-CoV-2-positive samples (2/680, 0.29%) and in three SARS-CoV-2-negative samples (3/350, 0.86%). WUPyV DNA was observed in one-one samples from both groups (1/680, 0.15% vs. 1/350, 0.29%). We did not find an association between SARS-CoV-2 and KIPyV or WUPyV infection, and we found low DNA prevalence of polyomaviruses studied after a long-term lockdown in Hungary. To exclude a geographically different distribution of these polyomaviruses, we studied the seroprevalence of KIPyV and WUPyV by enzyme-linked immunosorbent assay among children and adults (n = 692 for KIPyV and n = 705 for WUPyV). Our data confirmed that primary infections by KIPyV and WUPyV occur mainly during childhood; the overall seropositivity of adults was 93.7% and 89.2% for KIPyV and WUPyV, respectively. Based on our data, we suggest that the spread of KIPyV and WUPyV might have been restricted in Hungary by the lockdown.

Evaluation of the Antimicrobial and Antivirulent Potential of Essential Oils Isolated from Juniperus oxycedrus L. ssp. macrocarpa Aerial Parts.

As a consequence of the worsening situation with multidrug-resistant (MDR) pathogens and a disparity in the commercialization of novel antimicrobial agents, scientists have been prompted to seek out new compounds with antimicrobial activity from a wide range of sources, including medicinal plants. In the present study, the antibacterial, antifungal, anti-virulence, and resistance-modulating properties of the essential oil from the Sardinian endemic Juniperus oxycedrus L. ssp. macrocarpa aerial parts were evaluated. The GC/MS analysis showed that the main compounds in the oil were α-pinene (56.63 ± 0.24%), limonene (14.66 ± 0.11%), and ß-pinene (13.42 ± 0.09%). The essential oil showed potent antibacterial activity against Gram-positive bacteria (0.25-2 v/v%) and Salmonella spp. (4 v/v%). The strongest fungicidal activity was recorded against Candida auris sessile cells (median FICI was 0.088) but not against C. albicans biofilms (median FICI was 1). The oil showed potent efflux pump inhibitory properties in the case of Staphylococcus aureus and Escherichia coli. The therapeutic potential of Juniperus may be promising for future more extensive research and in vivo tests to develop new drugs against antibiotic and antifungal resistance.

Special Issue: Alternative Therapeutic Approaches of Candida Infections.

In recent decades, the prevalence of resistant fungal isolates has been steadily increasing both in veterinary and human medicine as well as in agriculture [...].

Concentration-Dependent Antibacterial Activity of Chitosan on Lactobacillus plantarum.

The antimicrobial effect of chitosan and synthetic chitosan derivatives has been confirmed on many Gram-positive and Gram-negative bacteria and fungi. The tests were carried out on pathogenic microorganisms, so the mechanism and concentration dependence of the inhibitory effect of chitosan were revealed. We conducted our tests on a probiotic strain, Lactobacillus plantarum. Commercially available chitosan derivatives of different molecular weights were added to L. plantarum suspension in increasing concentrations. The minimum inhibitory concentration (MIC) value of chitosan was determined and confirmed the viability decreasing effect at concentrations above the MIC with a time-kill assay. The release of bacterium cell content was measured at 260 nm after treatment with 0.001-0.1% concentration chitosan solution. An increase in the permeability of the cell membrane was observed only with the 0.1% treatment. The interaction was also investigated by zeta potential measurement, and the irreversible interaction and concentration dependence were established in all concentrations. The interaction of fluorescein isothiocyanate (FITC) labeled low molecular weight chitosan and bacterial cells labeled with membrane dye (FM® 4-64) was confirmed by confocal microscopy. In conclusion, the inhibitory effect of chitosan was verified on a probiotic strain, which is an undesirable effect in probiotic preparations containing chitosan additives, while the inhibitory effect experienced with pathogenic strains is beneficial.