Search Results (148)

Polymicrobial biofilms involving fungal and bacterial species are increasingly recognized as contributors to persistent infections, particularly in the oral cavity. Candida albicans and Aggregatibacter actinomycetemcomitans are two commensals that can turn into opportunistic pathogens and are able to form robust biofilms. Objectives: This study aimed to assess the interaction dynamics between these two microorganisms and to evaluate their susceptibility to fluconazole and azithromycin in single- and mixed-species forms. Methods: Biofilm biomass was quantified using crystal violet assays, while biofilm cell viability was assessed through CFU enumeration (biofilm viability assay). To assess the resistance properties of single versus mixed-species coincubations, we applied the antimicrobial susceptibility test (AST) to each drug, and analysed spatial organization with confocal laser scanning microscopy, using PNA-FISH. Results: The results indicated that both species can coexist without significant mutual inhibition. However, a non-reciprocal synergism was also observed, whereby mixed-species biofilm conditions promoted the growth of A. actinomycetemcomitans, while C. albicans growth remained stable. As expected, antimicrobial tolerance was elevated in mixed cultures, likely due to enhanced extracellular matrix production and potential quorum-sensing interactions, contributing to increased resistance against azithromycin and fluconazole. Conclusions: This study provides novel insights into previously rarely explored interactions between C. albicans and A. actinomycetemcomitans. These findings underscore the importance of investigating interspecies interactions within polymicrobial biofilms, as understanding their mechanisms, such as quorum-sensing molecules and metabolic cooperation, can contribute to improved diagnostics and more effective targeted therapeutic strategies against polymicrobial infections. Full article

Fungal prosthetic joint infection (fPJI) is one of the orthopaedic pathologies where there is no clear evidence, guidelines or algorithm to guide the surgeon in its management. This is in addition to the difficulty with which these infections are diagnosed, isolated and treated. Fungi form notorious biofilms that are difficult to eradicate once formed and that display resistance to antimicrobial agents. These biofilms have been shown to act synergistically with biofilms of bacteria, further adding to medical treatment resistance. We have reviewed the literature for reports that describe the results of different methods in surgically treating fPJI. We found that surgical management with two stages remains the gold standard for treatment of fPJI, as is the case for bacterial PJI (bPJI). We have investigated medical treatment, debridement with implant retention (DAIR) and staged revisions and whether a reasonable recommendation can be made based on the best knowledge and practice available. From the data on bPJI, there exists a role for conservative management of acute PJI with debridement, antibiotics and implant retention (DAIR). While fPJI and bPJI both represent infections, the differences in our ability to detect these infections clinically, culture the pathogens and treat them with proper antimicrobial agents, along with the difference in the reported results of the surgical treatment, make us believe that these two types of infections should not be treated in the same manner. With all this in mind, we reviewed several reports in the literature on fPJI to determine the efficacy of current treatment modalities, including DAIR, which followed current guidelines for PJI. Data show an overall treatment success rate of 64.4% [range 17.4–100%]. Subgroup analysis revealed a success rate of 11.6% [range 0–28.7%] in patients treated with DAIR. There is no doubt that DAIR should not be encouraged as it consistently has a bad record. Although there are not enough studies or numbers of patients to show an evidence-based preference over one- or two-staged revisions, the two-stage revision of fPJI consistently shows better results and should be considered as the gold standard of management in cases of revision fPJI. This should also be coupled with proper expertise, follow-ups and recommended lengths of medical treatment, which should not be less than six months. From the review of these data, we have developed reasonable recommendations for the management of fPJI. These recommendations center on staged surgical debridement along with medical management. Medical treatment should be for at least 6 months under the guidance of an infectious disease team and based on intraoperative cultures. In the case of local antimicrobial treatment reported in the literature, many patients with fPJI were found to have a polymicrobial infection. As a result, it is our recommendation that antifungals as well as antibacterials should be incorporated into the cement spacer mix of these cases. Fungal PJI remains an exceedingly difficult pathology to treat and should be managed by experienced surgeons in a well-equipped institution. Full article

The Qinghai-Xizang Plateau is among the most ecologically vulnerable and responsive areas worldwide. Studying the characteristics of soil microbial communities along altitudinal gradients on plateaus and revealing the response mechanisms and vertical distribution patterns of microbial communities in alpine ecosystems is of significant academic value for assessing the ecological stability of the Qinghai-Xizang Plateau. This research examines the Lhasa River Basin by employing Illumina NovaSeq high-throughput sequencing to investigate how soil bacterial and fungal communities shift across elevation gradients in the Duilong Qu subbasin. This study also explored the key environmental drivers behind these microbial distribution patterns. The results indicate the following: (1) Key bacterial groups in the Duilong Qu Basin soil include Proteobacteria, Acidobacteria, and Actinobacteria, with Ascomycota, Mortierellomycota, and Basidiomycota as the prevalent fungal phyla. (2) Soil bacterial richness fluctuates with increasing elevation, and diversity exhibits a V-shaped distribution; fungal richness increases monotonically with elevation, whereas diversity shows no altitudinal dependence. (3) Principal coordinate analysis (PCoA) revealed that bacterial community structures exhibit separation trends across different elevations, with high intragroup consistency; fungal community structures at mid-elevations (4000–5000 m) show clustering similarity, whereas those at 3650–5000 m and 5500 m remain highly distinct from those at other elevations. (4) RDA reveals that factors such as accessible phosphorus, potassium, and organic content have a major effect on how bacterial communities are arranged. On the other hand, soil conductivity, along with available and total phosphorus levels, as well as pH, plays a key role in shaping fungal communities. (5) Functional prediction analysis suggests that soil bacteria shift from aerobic and biofilm-forming to facultatively anaerobic, stress-tolerant, and pathogenic traits with increasing elevation. Fungi are predominantly undefined saprotrophs, transitioning from ectomycorrhizal and pathogenic functions to saprotrophic functions at relatively high elevations. Full article

Oral infections, caused by bacterial, fungal, and viral pathogens, are a significant source of dental morbidity and can lead to systemic complications, especially in immunocompromised individuals. Complex microbial interactions and host immune responses drive common conditions such as dental caries, periodontal disease, oral candidiasis, and herpetic lesions. Conventional antimicrobial therapies face limitations due to resistance and adverse effects, prompting interest in alternative treatments. Cannabidiol (CBD), a non-psychoactive compound derived from Cannabis sativa, has emerged as a promising candidate due to its antimicrobial, anti-inflammatory, and immunomodulatory properties. CBD targets various molecular pathways, including cannabinoid receptors, TRP channels, adenosine receptors, and PPARs, contributing to its multifaceted therapeutic effects. It has demonstrated efficacy against oral pathogens such as Streptococcus mutans, Enterococcus faecalis, and Candida albicans, disrupting biofilms and bacterial membranes. Additionally, CBD modulates inflammatory responses by reducing cytokine production and oxidative stress, particularly relevant in chronic conditions like periodontal disease. Emerging evidence also suggests synergistic effects with conventional antimicrobials and benefits in tissue regeneration. This review highlights the therapeutic potential of CBD in managing oral infections, offering a novel approach to overcoming current treatment limitations and guiding future research into safer and more effective oral health interventions. Full article

Macleania rupestris, a fruit-bearing species of the Ericaceae family, has traditionally been used for its potential medicinal properties. Background/Objectives: This study investigates the phytochemical composition and antimicrobial activity of M. rupestris fruit extract, focusing on its antibacterial, antibiofilm, and antifungal effects. Methods: M. rupestris (Kunth) A.C.Sm. berries (code: 4456, Herbario QUPS-Ecuador) were collected from the cloud forest Montano Alto, Cuenca-Ecuador, and the extract was obtained using an ethanolic-based extraction and chemically characterized. The antibacterial and antifungal activity of the fruit extract was assessed against seven multidrug-resistant bacteria strains and four fungal strains using the microdilution method. The biofilm inhibition potential was evaluated using a microplate assay with the crystal violet staining method. The antioxidant activity was evaluated using DPPH and ABTS assays. Results: The bioactive compounds showed 853.9 mg phenols/100 g DW, 573.2 mg organic acid/100 g DW, and 21.5 mg C-3-gl/100 g DW of anthocyanins. The antibacterial assays demonstrated significant inhibitory activity against Enterococcus faecalis, Enterococcus faecium, Escherichia coli, and Staphylococcus epidermidis, with MIC values ranging from 1.25 to 5 mg/mL. Additionally, the biofilm inhibition assays confirmed the potential of M. rupestris extract to disrupt bacterial biofilms, particularly in S. aureus and L. monocytogenes. Nevertheless, no significant antifungal activity was observed against Candida spp., suggesting selective antimicrobial properties. Finally, the antioxidant activity was strong (1.62 mmol TE/100 g DW by DPPH and 3.28 mmol TE/100 g DW by ABTS). Conclusions: These findings indicate that M. rupestris possesses promising antibacterial, antibiofilm, and antioxidant properties, which may be attributed to its phenolic and organic acid composition. Further fractionation and targeted bioassays are required to elucidate the specific bioactive compounds responsible for these effects and explore their potential applications in antimicrobial formulations. Full article

The rising prevalence of fungal infections, especially those caused by Candida species, presents a major risk to global health. With approximately 1.5 million deaths annually, the urgency for effective treatment options has never been greater. Candida spp. are the leading cause of invasive infections, significantly impacting immunocompromised patients and those in healthcare settings. C. albicans, C. parapsilosis and the emerging species C. auris are categorized as highly dangerous species because of their pathogenic potential and increasing drug resistance. This review comparatively describes the formation of microbial biofilms of both bacterial and fungal origin, including major pathogens, thereby creating a novel focus. Biofilms can further complicate treatment, as these structures provide enhanced resistance to antifungal therapies. Traditional antifungal agents, including polyenes, azoles and echinocandins, have shown effectiveness, yet resistance development continues to rise, necessitating the exploration of novel therapeutic approaches. Antimicrobial peptides (AMPs) such as the anti-biofilm peptides Pom-1 and Cm-p5 originally isolated from snails represent promising candidates due to their unique mechanisms of action and neglectable cytotoxicity. This review article discusses the challenges posed by Candida infections, the characteristics of important species, the role of biofilms in virulence and the potential of new therapeutic options like AMPs. Full article

Biofilms are structurally organized communities of microorganisms that adhere to a variety of surfaces. These communities produce protective matrices consisting of polymeric polysaccharides, proteins, nucleic acids, and/or lipids that promote shared resistance to various environmental threats, including chemical, antibiotic, and immune insults. While algal and bacterial biofilms are more apparent in the scientific zeitgeist, many fungal pathogens also form biofilms. These surprisingly common biofilms are morphologically distinct from the multicellular molds and mushrooms normally associated with fungi and are instead an assemblage of single-celled organisms. As a collection of yeast and filamentous cells cloaked in an extracellular matrix, fungal biofilms are an extreme threat to public health, especially in conjunction with surgical implants. The encapsulated yeast, Cryptococcus neoformans, is an opportunistic pathogen that causes both pulmonary and disseminated infections, particularly in immunocompromised individuals. However, there is an emerging trend of cryptococcosis among otherwise healthy individuals. C. neoformans forms biofilms in diverse environments, including within human hosts. Notably, biofilm association correlates with increased expression of multiple virulence factors and increased resistance to both host defenses and antifungal treatments. Thus, it is crucial to develop novel strategies to combat fungal biofilms. In this review, we discuss the development and treatment of fungal biofilms, with a particular focus on C. neoformans. Full article

The increasing use of biodegradable plastic mulch like polybutylene adipate terephthalate (PBAT) has raised concerns about its long-term environmental impact. In this study, we investigated the effects of multiyear PBAT mulch application on bacterial and fungal communities, assembly mechanisms, and key ecological functions. The microbial community diversity and composition were significantly altered after multiyear biodegradable plastic mulching. We observed that PBAT treatment enriched specific bacterial genera, such as Pantoea, potentially involved in plastic degradation, and fungal genera like Cephaliophora and Stephanosporaceae, which may play a role in organic matter decomposition. A null model analysis revealed that bacterial community assembly was largely shaped by deterministic processes, with stronger environmental selection pressures in PBAT-treated soils, while fungal communities were more influenced by stochastic processes. In addition, multiyear PBAT mulch application also impacted the functionality of the soil microbial communities. PBAT exposure enhanced biofilm formation in aerobic bacteria, promoting aerobic degradation processes while also reducing the abundance of stress-tolerant bacteria. Additionally, PBAT altered key microbial functions related to carbon, nitrogen, and sulfur cycling. Notably, the fungal communities exhibited functional shifts, with an increase in saprotrophic fungi being beneficial for nutrient cycling, alongside a potential rise in plant pathogenic fungi. These findings underscore the multiyear ecological impacts of biodegradable plastics, suggesting microbial adaptation to plastic degradation and changes in key ecological functions, with implications for agricultural sustainability and bioremediation strategies. Full article

Background/Objectives: Titanium dental implants, while highly successful, face challenges due to polymicrobial infections leading to peri-implantitis and implant failure. Biofilm formation on implant surfaces is the primary cause of these infections, with factors such as matrix production and cross-kingdom interactions contributing to the microbial accumulation of bacterial and fungal pathogens species. To combat this issue, naturally derived molecules have been reported to overcome the hurdle of antimicrobial resistance against the application of conventional antibiotics and antifungals. Methods: The present study aimed to employ the lichen-derived molecules, usnic acid (UA), to retard the development of biofilms of bacterial and fungal pathogens on the surface of titanium kept in the human artificial saliva (HAS) working as a growth-supporting, host-mimicking media. Results: The minimum inhibitory concentration of UA in HAS towards Candida albicans was >512 µg/mL, whereas against Staphylococcus aureus and Streptococcus mutans, it was determined to be 512 µg/mL. Whereas, in the standard growth media, the MIC value of UA towards S. mutans and S. aureus were 8 and 16 µg/mL; however, against C. albicans, it was 512 µg/mL. UA synergistically enhanced the efficacy of the antibiotics toward bacterial pathogens and the efficacy of antifungals against C. albicans. The antibiofilm results depict the fact that in the HAS, UA significantly reduced both mono-species of S. mutans, S. aureus, and C. albicans and mixed-species biofilm of C. albicans with S. mutans and S. aureus on the surface of the titanium. Conclusions: The present study showed that UA is a promising natural drug that can control oral polymicrobial disease as a result of the application of dental implants. Full article

Fungal periprosthetic joint infections (PJIs) are rare but increasingly recognized complications following total joint arthroplasty (TJA). While Candida albicans remains the most common pathogen, non-albicans Candida species and other fungi, such as Aspergillus, have gained prominence. These infections often present with subtle clinical features and affect patients with significant comorbidities or immunosuppression. Compared to bacterial PJIs, fungal infections pose unique diagnostic and therapeutic challenges, including biofilm formation, limited antifungal susceptibility, and protracted treatment courses. This narrative review synthesizes current evidence from research articles and review/metanalysis papers, focusing on fungal PJIs. The literature search encompassed publications from 2015 to 2024, identifying key insights on epidemiology, risk factors, microbiological profiles, diagnostic methods, therapeutic strategies, and outcomes. Both classical references and recent studies addressing emerging diagnostic biomarkers and biofilm-active therapies were included. It was shown that C. albicans remains the primary fungal pathogen in PJIs but non-albicans Candida species and other fungi are associated with more complex clinical scenarios, higher recurrence rates, and reduced infection-free survival. Patients commonly exhibit multiple comorbidities, compromised immune status, and previous prosthetic revisions. Diagnosis is complicated by slow-growing organisms and nonspecific inflammatory markers, prompting interest in novel diagnostics such as alpha-defensin, calprotectin, and next-generation sequencing. Two-stage revision arthroplasty, supplemented by prolonged targeted antifungal therapy, is considered the gold standard for chronic infections, although outcomes remain inferior to bacterial PJIs. Emerging strategies, including antifungal-impregnated beads and biofilm-disrupting agents, may improve local infection control. In conclusion, fungal PJIs constitute a challenging clinical entity demanding tailored diagnostic and therapeutic approaches. Further research into standardized diagnostic criteria, optimized antifungal regimens, biomarker validation, and refined surgical strategies is essential. Multidisciplinary collaboration, enhanced patient optimization, and innovative biofilm-directed therapies hold promise for improving outcomes and reducing the burden of fungal PJIs. Full article

To obtain an effective bacterial biocontrol strain against the fungal pathogen Ganoderma pseudoferreum, causing rubber tree red root rot disease, healthy rubber tree tissue from Baisha County, Hainan Province, was selected as the isolation source, and bacterial strains with strong antifungal effects against G. pseudoferreum were screened. The strain was identified by molecular biology, in vitro root segment tests, pot growth promotion tests, and genome detection. The strain was further evaluated by biological function tests, genome annotation analysis, and plant defense-related enzyme activity detection. The results show that strain LSR7 had good antagonistic effects against G. pseudoferreum, and the inhibition rate reached 88.49%. The strain LSR7 was identified as Bacillus velezensis by genome sequencing. In a greenhouse environment, LSR7 prevents and treats red root rot disease in rubber trees and promotes the growth of rubber tree seedlings. LSR7 secreted cell wall hydrolases (protease, glucanase, and cellulase), amylases, and siderophores. LSR7 also formed biofilms, facilitating plant colonization. Genome prediction showed that LSR7 secreted multiple antifungal lipopeptides. LSR7 enhanced rubber tree resistance to G. pseudoferreum by increasing the activity of defense enzymes. Bacillus velezensis LSR7 has biocontrol potential and is a candidate strain for controlling red root rot disease in rubber trees. Full article

Solenopsis invicta, a South American ant species from the Formicidae family (subfamily Myrmicinae), has recently established a stable settlement in Europe, raising public health concerns due to its venomous stings. The venom of S. invicta is rich in bioactive molecules, particularly piperidine alkaloids such as solenopsin A and peptides (Sol 1–4). These compounds have been implicated in various health applications, including antimicrobial, anti-inflammatory, and antitumour activities. While previous reviews have focused on the ecological and allergenic risks posed by S. invicta, this scoping review aims to evaluate the potential therapeutic uses of S. invicta venom by summarizing existing scientific evidence and providing a novel synthesis of recent research on its bioactive components. Furthermore, this study, by describing the unique biological aspects of S. invicta, provides an overview of its direct impact on public health, highlighting new findings on the venom’s role in inhibiting bacterial biofilm formation and modulating cancer growth pathways through gene regulation. A search of databases (PubMed, Scopus, Science Direct, and Cochrane Library) identified 12,340 articles, from which 11 studies met the eligibility criteria. These studies included seven microbiological investigations and four studies on tumour cell lines and animal models. The findings suggest that S. invicta venom could inhibit biofilm formation, combat fungal infections, and suppress tumour growth. However, further research, including clinical trials, is required to fully elucidate the safety and efficacy of these bioactive molecules in human medicine, for their potential use in drug discovery to counteract several diseases, including cancer. Full article

Due to the possible coexistence of Klebsiella pneumoniae (KP) and Candida albicans (CA), strains of KP and CA with biofilm production properties clinically isolated from patients were tested. The production of biofilms from the combined organisms (KP+CA) was higher than the biofilms from each organism alone, as indicated by crystal violet and z-stack immunofluorescence. In parallel, the bacterial abundance in KP + CA was similar to KP, but the fungal abundance was higher than CA (culture method), implying that CA grows better in the presence of KP. Proteomic analysis was performed to compare KP + CA biofilm to KP biofilm alone. With isolated mouse neutrophils (thioglycolate induction), KP + CA biofilms induced less prominent responses than KP biofilms, as determined by (i) neutrophilic supernatant cytokines (ELISA) and (ii) neutrophil extracellular traps (NETs), using immunofluorescent images (neutrophil elastase, myeloperoxidase, and citrullinated histone 3), peptidyl arginine deiminase 4 (PAD4) expression, and cell-free DNA. Likewise, intratracheal KP + CA in C57BL/6 mice induces less severe pneumonia than KP alone, as indicated by organ injury (serum creatinine and alanine transaminase) (colorimetric assays), cytokines (ELISA), bronchoalveolar lavage fluid parameters (bacterial culture and neutrophil abundances using a hemocytometer), histology score (H&E stains), and NETs (immunofluorescence on the lung tissue). In conclusion, the biofilm biomass of KP + CA was mostly produced from CA with less potent neutrophil activation and less severe pneumonia than KP alone. Hence, fungi in the respiratory tract might benefit the host in some situations, despite the well-known adverse effects of fungi. Full article

Candida albicans are ubiquitous fungal organisms that colonize the oral cavity of healthy individuals without causing disease. C. albicans is an opportunistic microorganism with several virulent factors that influence the inflammatory process and allow it to invade tissues, evade host defense mechanisms, and release toxins, facilitating proliferation and degradation. At present, increasing emphasis is placed on polymicrobial interactions between C. albicans and various bacterial pathogens. Such interaction is mutually beneficial for both parties: it is competitive and antagonistic. Their complex interaction and colonization in the oral cavity serve as the basis for several oral diseases. The dispersion of C. albicans in saliva and the systemic circulation is noted in association with other bacterial populations, suggesting their virulence in causing disease. Hence, it is necessary to understand fungal–bacterial interactions for early detection and the development of novel therapeutic strategies to treat oral diseases. In this paper, we review the mutualistic interaction of C. albicans in oral biofilm formation and polymicrobial interactions in oral diseases. In addition, C. albicans virulence in causing biofilm-related oral diseases and its presence in saliva are discussed. Full article

One of the major global health threats in the present era is antibiotic resistance. Biosynthesized iron oxide nanoparticles (FeNPs) can combat microbial infections and can be synthesized without harmful chemicals. In the present investigation, 16S rRNA gene sequencing was used to discover Streptomyces sp. SMGL39, an actinomycete isolate utilized to reduce ferrous sulfate heptahydrate (FeSO₄.7H₂O) to biosynthesize FeNPs, which were then characterized using UV–Vis, XRD, FTIR, and TEM analyses. Furthermore, in our current study, the biosynthesized FeNPs were tested for antimicrobial and antibiofilm characteristics against different Gram-negative, Gram-positive, and fungal strains. Additionally, our work examines the biosynthesized FeNPs’ molecular docking and binding affinity to key enzymes, which contributed to bacterial infection cooperation via quorum sensing (QS) processes. A bright yellow to dark brown color shift indicated the production of FeNPs, which have polydispersed forms with particle sizes ranging from 80 to 180 nm and UV absorbance ranging from 220 to 280 nm. Biosynthesized FeNPs from actinobacteria significantly reduced the microbial growth of Fusarium oxysporum and L. monocytogenes, while they showed weak antimicrobial activity against P. aeruginosa and no activity against E. coli, MRSA, or Aspergillus niger. On the other hand, biosynthesized FeNPs showed strong antibiofilm activity against P. aeruginosa while showing mild and weak activity against B. subtilis and E. coli, respectively. The collaboration of biosynthesized FeNPs and key enzymes for bacterial infection exhibits hydrophobic and/or hydrogen bonding, according to this research. These results show that actinobacteria-biosynthesized FeNPs prevent biofilm development in bacteria. Full article