species are fungal pathogens known for their ability to cause superficial and systemic infections in the human host. These pathogens are able to persist inside the host due to the development of ...pathogenicity and multidrug resistance traits, often leading to the failure of therapeutic strategies. One specific feature of
species pathogenicity is their ability to form biofilms, which protects them from external factors such as host immune system defenses and antifungal drugs. This review focuses on the current threats and challenges when dealing with biofilms formed by
, and
, highlighting the differences between the four species. Biofilm characteristics depend on the ability of each species to produce extracellular polymeric substances (EPS) and display dimorphic growth, but also on the biofilm substratum, carbon source availability and other factors. Additionally, the transcriptional control over processes like adhesion, biofilm formation, filamentation, and EPS production displays great complexity and diversity within pathogenic yeasts of the
genus. These differences not only have implications in the persistence of colonization and infections but also on antifungal resistance typically found in
biofilm cells, potentiated by EPS, that functions as a barrier to drug diffusion, and by the overexpression of drug resistance transporters. The ability to interact with different species in
biofilms is also a key factor to consider when dealing with this problem. Despite many challenges, the most promising strategies that are currently available or under development to limit biofilm formation or to eradicate mature biofilms are discussed.
Microplastics (MPs) contamination is becoming a significant environmental issue, as the widespread omnipresence of MPs can cause many adverse consequences for both ecological systems and humans. ...Contrary to what is commonly thought, the toxicity-inducing MPs are not the original pristine plastics; rather, they are completely transformed through various surface functional groups and aggressive biofilm formation on MPs via aging or weathering processes. Therefore, understanding the impacts of MPs' surface functional groups and biofilm formation on biogeochemical processes, such as environmental fate, transport, and toxicity, is crucial. In this review, we present a comprehensive summary of the distinctive impact that surface functional groups and biofilm formation of MPs have on their significant biogeochemical behavior in various environmental media, as well as their toxicity and biological effects. We place emphasis on the role of surface functional groups and biofilm formation as a means of influencing the biogeochemical processes of MPs. This includes their effects on pollutant fate and element cycling, which in turn impacts the aggregation, transport, and toxicity of MPs. Ultimately, future research studies and tactics are needed to improve our understanding of the biogeochemical processes that are influenced by the surface functional groups and biofilm formation of MPs.
A brief illustration for the surface functional groups and biofilm formation on microplastics and their environmental impact. Display omitted
•The surface formation of functional groups and biofilm on MPs were focused.•The impact of MPs' functional groups and biofilm on pollutant fate was elucidated.•The impact of functional groups and biofilm on MPs' environment fate was clarified.•Future works about MPs' functional groups and biofilm formation were discussed.
Although Tween-20 was used as an important catalyst to increase chalcopyrite bioleaching rate by acidophiles, the effect of Tween-20 on initial adhesion and biofilm development of acidophiles on ...chalcopyrite has not been explored until now. Herein, the role of Tween-20 in early attachment behaviors and biofilm development by Acidianus manzaensis strain YN-25 were investigated by adhesion experiments, adhesion force measurement, visualization of biofilm assays and a series of analyses including extended Derjaguin Landau Verwey Overbeek (DLVO) theory, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The bacterial adhesion experiments showed that 2 mg/L of Tween-20 increased the adhesion percentage (by 8%) of A. manzaensis YN-25. Tween-20 could promote the early adhesion of A. manzaensis YN-25 by changing the Lewis acid-base interaction and electrostatic force to increase total interaction energy and adhesion force. Besides, the functional groups on the surface of cells (carboxyl, hydroxyl and amino functional groups) contributed to the adhesion of A. manzaensis YN-25 on chalcopyrite. Furthermore, the promotion of biofilm formation by Tween-20 was mainly attributed to the reduction of S0 passivation layer formation and complexing more Fe3+ on chalcopyrite surface, contributing to the erosion of chalcopyrite and creating more corrosion pits. Live/dead staining showed low live/dead ratio (ranged from 0.35 to 1.32) during the biofilm development process. This report offers a better understanding of the effects of Tween-20 on attachment and biofilm development of acidophilic microorganisms and would lay a theoretical foundation for the better application of catalyst in bioleaching.
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•Tween-20 promoted the adhesion of A. manzaensis on the chalcopyrite surface.•Tween-20 increased the interaction force between A. manzaensis and chalcopyrite.•GAB and GEL played a major role in initial adhesion in the presence of Tween-20.•Tween-20 promoted biofilm formation on chalcopyrite.•Mechanisms included S0 passivation layer reduction and promotion dissolution.
Wheat is one of the most important strategic products in providing food security for the growing world population. The purpose of this research is to isolate and identify plant growth-promoting ...bacteria from the wheat rhizosphere and their inhibitory effect on the growth of the pathogenic fungus Fusarium sp. isolated from wheat. The initial screening of 100 bacterial strains isolated from wheat roots was done based on their ability to dissolve phosphate. The effective factors in plant growth and inhibition of fungal pathogens, such as the ability to produce IAA, siderophores, protease, biofilm, bacterial swarming motility, tolerance to salt, seed germination, and seed vigor tests, were investigated. In the initial screening, four bacterial isolates with the highest amount of phosphate dissolution were identified based on morphological and biochemical characteristics as well as the sequence of 16S rRNA region belonging to Curtobacterium sp., Arthrobacter sp., Acinetobacter calcoaceticus, and Cellulosimicrobium sp.; Curtobacterium sp. had the highest amount of IAA (6.14μg/ml), siderophore (2.25cm), protease (1.4cm), and the highest tolerance to salinity (20%) and phosphate dissolution (375.3mg/ml). In the swarming motility test, the highest values were related to Arthrobacter sp. and Curtobacterium sp. at 2.7 and 2.2cm, respectively. The highest amount of biofilm formation was associated with Acinetobacter calcoaceticus and Curtobacterium sp. with an average absorption coefficient of 0.153 and 0.139, respectively. The highest and lowest average values of percentage inhibition of pathogenic fungus colony growth were evaluated in Curtobacterium sp. isolate with a value of 57.3%, and Cellulosimicrobium sp. isolate with 33%, respectively.
Wound healing involves a complex interaction between immunity and other natural host processes, and to succeed it requires a well-defined cascade of events. Chronic wound infections can be mono- or ...polymicrobial but their major characteristic is their ability to develop a biofilm. A biofilm reduces the effectiveness of treatment and increases resistance. A biofilm is an ecosystem on its own, enabling the bacteria and the host to establish different social interactions, such as competition or cooperation. With an increasing incidence of chronic wounds and, implicitly, of chronic biofilm infections, there is a need for alternative therapeutic agents. Nanotechnology shows promising openings, either by the intrinsic antimicrobial properties of nanoparticles or their function as drug carriers. Nanoparticles and nanostructured coatings can be active at low concentrations toward a large variety of infectious agents; thus, they are unlikely to elicit emergence of resistance. Nanoparticles might contribute to the modulation of microbial colonization and biofilm formation in wounds. This comprehensive review comprises the pathogenesis of chronic wounds, the role of chronic wound colonization and infection in the healing process, the conventional and alternative topical therapeutic approaches designed to combat infection and stimulate healing, as well as revolutionizing therapies such as nanotechnology-based wound healing approaches.
Abstract
Salmonella is one of the most important foodborne and zoonotic pathogens, and monophasic S. Typhimurium is ranked among the top-five Salmonella serovars causing animal and human infections ...worldwide. Resistance to the third- and higher-generation cephalosporins in Salmonella has attracted great attention. Bacteria are frequently exposed to sub-minimal inhibitory concentrations (sub-MICs) of antimicrobials that can trigger diverse adaptive responses such as biofilm formation. Biofilms can promote bacterial defense to external and internal harsh conditions. This study aimed to investigate the effect of sub-MICs of cefotaxime, one of the third-generation cephalosporins, on biofilm formation by non-clinical S. enterica strains. Crystal violet staining demonstrated that cefotaxime at 1/8 MIC enhanced biofilm formation by two monophasic S. Typhimurium strains. Confocal laser scanning microscopy and enzymatic treatment assay revealed that cellulose was the most dominant extracellular matrix component contributing to Salmonella biofilm formation. Scanning electron microscopy demonstrated that cefotaxime treatment led to bacterial incomplete cell division and filamentous morphology during the whole process of biofilm formation. Our study is the first to report the enhancement effect of cefotaxime on non-clinical, monophasic S. Typhimurium by affecting bacterial morphology. The results will contribute to conducting risk assessments of Salmonella in the pork production chain and guiding the rational use of antimicrobial agents to reduce the risk of biofilm formation.
is a fungus that lives primarily on the mucosal surfaces of healthy humans, such as the oral cavity, vagina, and gastrointestinal tract. This commensal organism can be controlled by other microbiota, ...while certain conditions can increase the risk of
outgrowth and cause disease. Prevalence of the drug-resistant phenotype, as well as the severity of
infection in immunocompromised patients, presents a challenge for scientists to develop novel, effective treatment, and prevention strategies. β-Citronellol is an intriguing active compound of several plants that has been linked to antifungal activity, but data on the mechanism of action in terms of proteomic profiling are lacking. Here, β-citronellol identified from
DC. leaf against
were evaluated. A proteomic approach was used to identify potential target proteins involved in the mode of action of β-citronellol. This study identified and discussed three protein groups based on the 126 major proteins that were altered in response to β-citronellol treatment, 46 of which were downregulated and 80 of which were upregulated. Significant protein groups include cell wall proteins (e.g., Als2p, Rbt1p, and Pga4p), cellular stress response enzymes (e.g., Sod1p, Gst2p, and Ddr48p), and ATP synthesis-associated proteins (e.g., Atp3p, Atp7p, Cox1p, and Cobp). Results demonstrated the complexities of protein interactions influenced by β-citronellol treatment and highlighted the potential of antifungal activity for future clinical and drug development research.
Persistent bacterial infections caused by biofilm-associated Shigella spp. are a global public health concern. The following study aims to determine the antibacterial activity and possible mechanism ...that gallic acid (GA) displays against Shigella flexneri (Sh. flexneri) and its effect on the biofilm formation. The minimum inhibitory concentration (MIC) and the minimal bactericidal concentration (MBC) values that GA exhibited against planktonic Sh. flexneri were 2 mg/mL and 8 mg/mL. The time-kill curves showed that the concentration and the treatment time of GA led to inhibitory effects, which was evidenced by reduced cell viability, destroyed cell membranes, and changes in the bacterial morphology. GA was shown to have a significant inhibition effect on the Sh. flexneri biofilm formation and infiltrated into the EPS, which reduced the number of viable bacteria. Further studies showed that the expression of the mdoH gene and the OpgH protein was inhibited in the Sh. flexneri biofilm cells. The polysaccharide contents in the biofilm decreased. The results suggested that GA effectively inhibited planktonic Sh. flexneri activity and its biofilm formation by regulating the expression of the mdoH gene and the OpgH protein. These findings indicated that GA has potential use as a natural and a safe alternative for controlling the growth of the Sh. flexneri biofilm.
•The antibacterial effect of gallic acid against planktonic Sh. flexneri was assessed.•Gallic acid reduced the Sh. flexneri viability and destroyed the cell morphology.•Gallic acid exhibited significant inhibition effect on Sh. flexneri biofilm formation.•The expression of mdoH gene and the OpgH protein effected by gallic acid was investigated.
Lactobacilli have been considered as major contributors to human dental caries for over a century. Recent
model studies have shown that when compared to
a keystone pathogen of human dental caries, ...the ability of lactobacilli to form biofilms is poor, although differences exist between the different major species. Further studies using molecular and bioinformatics approaches provide evidence that multiple mechanisms, including adhesin-receptor mediated physical contact with
, facilitate the adherence and establishment of lactobacilli on the tooth surface. There is also evidence that under conditions like continuous sugar consumption, weak acids and other antimicrobials such as bacteriocins from lactobacilli can become detrimental to the microbial community, especially those in the proximity. Details on the underlying mechanisms of how different
sp. establish and persist in the highly complex microbiota on the tooth surface await further investigation.
The current study was conducted to evaluate the antibacterial combination efficacies, and whether the sub-inhibitory concentrations (sub-MIC) of antibiotics can influent on the biofilm formation of
. ...The minimum inhibitory concentration (MIC) of common antibacterial drugs was determined
against clinical isolates of
(
),
(
), and
(
) alone and in combination with each other by using the broth microdilution method and the checkerboard micro-dilution method analyzed with the fractional inhibitory concentration index (FICI), respectively. Regarding these results, antibacterial drug combinations were categorized as synergistic, interacting, antagonistic and indifferent, and most of the results were consistent with the previous reports. Additionally, the effects of sub-MIC of seven antimicrobials (kanamycin, acetylisovaleryltylosin tartrate, enrofloxacin, lincomycin, colistin sulfate, berberine, and clarithromycin) on
biofilm formation were determined
crystal violet staining, scanning electron microscopy (SEM) and real-time PCR. Our results demonstrate that all antibiotics, except acetylisovaleryltylosin tartrate, effectively reduced the
biofilm formation. In addition, real-time reverse transcriptase PCR was used to analyze the relative expression levels of
biofilm-related genes such as
,
, and
after the treatment at sub-MIC with all of the six antimicrobials. All antibiotics significantly inhibited the expression of these biofilm-related genes except for acetylisovaleryltylosin tartrate, which efficiently up-regulated these transcripts. These results provide the theoretical parameters for the selection of effective antimicrobial combinations in clinical therapy and demonstrate how to correctly use antibiotics at sub-MIC as preventive drugs.
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