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Background: Sporotrichosis is a zoonotic disease caused by the dimorphic fungus Sporothrix spp., leading to skin lesions that can, in some cases, progress and result in the death of infected individuals. Candida albicans is another fungus involved in several skin, oral, and vaginal mucosal infections. Fungal diseases are concerning due to increasing incidence and the limited variety of antifungal classes available for treatment. Furthermore, antifungal medications can cause various side effects, exacerbated by their prolonged use during infection treatment. There is a need to explore alternatives to conventional drugs that are effective, fast, and safe in combating sporotrichosis. This study aimed to achieve in vitro elimination of the fungi Sporothrix brasiliensis and Sporothrix schenckii through Photodynamic Inactivation (PDI), using curcumin as a photosensitizer and in combination with antifungal agents used in the treatment of sporotrichosis., Methodology: Yeasts of Candida albicans, Sporothrix brasiliensis, and Sporothrix schenckii were subjected to Photodynamic Inactivation (PDI) using light at a wavelength of 450 ± 10 nm, irradiance of 35 mW/cm2, delivering a fluence of 31.5 J/cm2, with curcumin as the photosensitizer at doses ranging from 0.75 to 150 μg/mL. After determining the Minimum Inhibitory Concentration (MIC) values of the antifungal drugs itraconazole, ketoconazole, and potassium iodide, sub-MIC doses of these antifungals were combined with sub-MIC doses of curcumin in a new PDI session., Conclusion: Photodynamic inactivation is a promising technique in the treatment of sporotrichosis, as well as its combination with antifungals. The combination of curcumin in concentrations ranging from 0.75 g/mL a 7.5 g/mL with sub-MIC concentrations of itraconazole, ketoconazole, and potassium iodide was able to completely inactivate the fungi C. albicans, S. brasiliensis and S. schenckii, indicating that PDI may increase the effectiveness of antifungals. However, further studies are needed to establish protocols for future clinical applications., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Rocha et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Background: The standard of care for disinfecting needleless connectors (NCs) of central venous catheters includes alcohol-containing caps or up to a 15-second scrub with alcohol or chlorhexidine. Due to the clinical impact and high cost of treating Central line-associated bloodstream infections (CLABSI), reducing the incidence of CLABSI is a priority for public health and of the Centers for Disease Control. Alcohol-containing caps have been demonstrated to disinfect external NC surfaces, but not the internal surface. Ultraviolet light (UV-C) is a strategy for disinfection of NC internal and external surfaces., Methods: Four clinically relevant bacteria (Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Pseudomonas aeruginosa) and Candida albicans were inoculated on NCs. Disinfection efficacy was measured after exposure to one second of 285 nm UV-C light at 48 mW/cm 2 in a proprietary handheld device and UV-C transparent NC or standard of care. Disinfection of internal and external surfaces of NC inoculated with S aureus using alcohol caps, and UV-C was also compared., Results: A 4-log reduction in colony forming units (CFUs) on the interior and exterior surfaces of the UV-transparent NC of clinically relevant pathogens was observed with UV-C light at this power for 1 second., Discussion: We demonstrated the efficacy of UV-C for the disinfection of NCs in one second using the UV-C device in benchtop studies., Conclusions: This device holds promise for reducing CLABSI, and clinical studies are planned., (Published by Elsevier Inc.)

In recent years, some microorganisms have shown resistance to conventional treatments. Considering this increase in resistant pathogens, treatment alternatives are needed to promote greater treatment efficiency. In this sense, antimicrobial photodynamic therapy (aPDT) has been an alternative treatment. This technique uses a photosensitizer that is activated by light with a specific wavelength producing reactive species, leading to the death of pathogenic microorganisms. In this study, bacteriochlorophyll derivatives such as bacteriochlorin metoxi (Bchl-M) and bacteriochlorin trizma (Bchl-T) obtained from purple bacterium (Rhodopseudomonas faecalis), were evaluated as photosensitizers in the aPDT. Photodynamic inactivation (PDI) of the microorganisms Staphylococcus aureus, Micrococcus luteus, Candida albicans and Pseudomonas aeruginosa was investigated with both bacteriochlorins (Bchl-M and Bchl-T) at different concentrations (1, 15 and 30 µM for S. aureus; 1, 15, 30, 45, 60 and 75 µM for M. luteus; 30, 60, 90, 105, 120 and 150 µM for C. albicans; and 200 µM for P. aeruginosa) and different doses of light (20 and 30 J/cm 2 for S. aureus and M. luteus; 30 and 45 J/cm 2 for C. albicans; and 45 J/cm 2 for P. aeruginosa) to inactivate them. Both photosensitizers showed good activation against S. aureus and for M. luteus, we observed the inactivation of these microorganisms at approximately 3 log, showing to be a good photosensitizers for these microorganisms., (© 2024. The Author(s) under exclusive licence to Sociedade Brasileira de Microbiologia.)

Objectives: To assess the growth of a multispecies biofilm on root canal dentin under different radiotherapy regimens., Materials and Methods: Sixty-three human root dentin cylinders were distributed into six groups. In three groups, no biofilm was formed (n = 3): NoRT) non-irradiated dentin; RT55) 55 Gy; and RT70) 70 Gy. In the other three groups (n = 18), a 21-day multispecies biofilm (Enterococcus faecalis, Streptococcus mutans, and Candida albicans) was formed in the canal: NoRT + Bio) non-irradiated + biofilm; RT55 + Bio) 55 Gy + biofilm; and RT70 + Bio) 70 Gy + biofilm. The biofilm was quantified (CFUs/mL). Biofilm microstructure was assessed under SEM. Microbial penetration into dentinal tubules was assessed under CLSM. For the biofilm biomass and dentin microhardness pre- and after biofilm growth assessments, 45 bovine dentin specimens were distributed into three groups (n = 15): NoRT) non-irradiated + biofilm; RT55 + Bio) 55 Gy + biofilm; and RT70 + Bio) 70 Gy + biofilm., Results: Irradiated specimens (70 Gy) had higher quantity of microorganisms than non-irradiated (p = .010). There was gradual increase in biofilm biomass from non-irradiated to 55 Gy and 70 Gy (p < .001). Irradiated specimens had greater reduction in microhardness after biofilm growth. Irradiated dentin led to the growth of a more complex and irregular biofilm. There was microbial penetration into the dentinal tubules, regardless of the radiation regimen., Conclusion: Radiotherapy increased the number of microorganisms and biofilm biomass and reduced dentin microhardness. Microbial penetration into dentinal tubules was noticeable., Clinical Relevance: Cumulative and potentially irreversible side effects of radiotherapy affect biofilm growth on root dentin. These changes could compromise the success of endodontic treatment in oncological patients undergoing head and neck radiotherapy., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Candida albicans is a pathogenic fungus that undergoes morphological transitions between hyphal and yeast forms, adapting to diverse environmental stimuli and exhibiting distinct virulence. Existing research works on antifungal blue light (ABL) therapy have either focused solely on hyphae or neglected to differentiate between morphologies, obscuring potential differential effects. To address this gap, we established a novel dataset of 150 C. albicans-infected mouse skin tissue slice images with meticulously annotated hyphae and yeast. Eleven representative convolutional neural networks were trained and evaluated on this dataset using seven metrics to identify the optimal model for segmenting hyphae and yeast in original high pixel size images. Leveraging the segmentation results, we analyzed the differential impact of blue light on the invasion depth and density of both morphologies within the skin tissue. U-Net-BN outperformed other models in segmentation accuracy, achieving the best overall performance. While both hyphae and yeast exhibited significant reductions in invasion depth and density at the highest ABL dose (180 J/cm2), only yeast was significantly inhibited at the lower dose (135 J/cm2). This novel finding emphasizes the importance of developing more effective treatment strategies for both morphologies., (© The Author(s) 2024. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology.)

Objective: The goal of this study is to investigate the efficacy, safety, and mechanism of ABL for inactivating Candida albicans (C. albicans), and to determine the best wavelength for treating candida infected disease, by experimental measurements and dynamic modeling., Methods: The changes in reactive oxygen species (ROS) in C. albicans and human host cells under the irradiation of 385, 405, and 415 nm wavelengths light with irradiance of 50 mW/cm 2 were measured. Moreover, a kernel-based nonlinear dynamic model, i.e., nonlinear autoregressive with exogenous inputs (NARX), was developed and applied to predict the concentration of light-induced ROS, whose kernels were selected by a newly developed algorithm based on particle swarm optimization (PSO)., Results: The ROS concentration was increased respectively about 10-12 times in C. albicans and about 3-6 times in human epithelial cells by the ABL treatment with the same fluence of 90 J/cm 2 . The NARX models were respectively fitted to the data from the experiments on both types of cells. Besides, four different kernel functions, including Gaussian, Laplace, linear and polynomial kernels, were compared in their fitting accuracies. The errors with the Laplace kernel turned out to be only 0.2704 and 0.0593, as respectively fitted to the experimental data of the C. albicans and human host cells., Conclusion: The results demonstrated the effectiveness of the NARX modeling approach, and revealed that the 415 nm light was more effective as an anti-fungal treatment with less damage to the host cells than the 405 or 385 nm light., Significance: The kernel-based NARX model identification algorithm offers opportunities for determining the effective and safe light dosages in treating various fungal infection diseases.

Background: Photodynamic therapy (PDT) activates a photosensitizer by visible light to generate cytotoxic oxygen species that lead to cell death. With proper illumination, PDT is often used in applications on superficial and sub-surface lesions. Sporotrichosis infection occurs by Sporothrix fungi which causes a skin wound, worsened by Candida albicans infections. This study investigated the photosensitizing efficiency of the Ru(phen) 2 (pPDIp)(PF 6 ) 2 complex, RupPDIp, against S. brasiliensis and C. albicans., Material and Methods: RupPDIp efficiency against these fungi was tested using 450 nm (blue light and 36 J/cm 2 ) and 525 nm (green light, 25.2 J/cm 2 ) at 0.05-20 μM concentrations. To ensure PDT effectiveness, control groups were tested in the absence and in the presence of RupPDIp under light irradiation and in the dark., Results: RupPDIp eliminated both fungi at ≤5.0 μM. Green light showed the best results, eliminating S. brasiliensis and C. albicans colonies at RupPDIp 0.5 μM and 0.05 μM, respectively., Conclusion: RupPDIp is a promising photosensitizer in aPDT, eliminating 10 6  CFU/mL of both fungi at 450 nm and 525 nm, with lower light doses and concentrations when treated with the green light compared to the blue light., (Copyright © 2022 Elsevier B.V. All rights reserved.)

In this work, we present Co 3 S 4 -SnO 2 supported polyvinylpyrrolidone-cellulose (PVPCS) nano-structure for Lidocaine degradation. The nanostructure was characterized by various techniques i.e. morphological and optical ones. The results have demonstrated that Co 3 S 4 -SnO 2 nanocomposites were evenly supported on the PVPCS. Moreover, the photocatalysis performances of the catalysts were investigated under ultra-violet (UV) light irradiation. The nano-structure Co 3 S 4 -SnO 2 /PVPCS composite (98.72%) revealed the highest photocatalysis performance as compared to SnO 2 nanoparticles, and Co 3 S 4 -SnO 2 nanocomposites. The photo-stability of nano-structure Co 3 S 4 -SnO 2 /PVPCS composite was characterized using cyclic catalytic experimental. Results demonstrated a substantially stable performance of the nano-structure Co 3 S 4 -SnO 2 /PVPCS composite. The biological properties of Co 3 S 4 -SnO 2 /PVPCS composite were investigated through the antibacterial (versus Staphylococcus aureus, and Escherichia coli) and antifungal studies (Candida albicans). As the results declared, Co 3 S 4 -SnO 2 nanocomposites have substantial biological properties as compared to SnO 2 nanoparticles, and Co 3 S 4 -SnO 2 nanocomposites., (Copyright © 2020. Published by Elsevier B.V.)

Background and Objective: Candida albicans is an opportunistic fungal pathogen of clinical importance and is the primary cause of fungal-associated wound infections, sepsis, or pneumonia in immunocompromised individuals. With the rise in antimicrobial resistance, it is becoming increasingly difficult to successfully treat fungal infections using traditional antifungals, signifying that alternative non-traditional approaches must be explored for their efficacy., Study Design/materials and Methods: We investigated the combination of antimicrobial blue light (aBL) and quinine hydrochloride (Q-HCL) for improved inactivation of C. albicans, in vitro and in vivo, relative to either monotherapy. In addition, we evaluated the safety of this combination therapy in vivo using the TUNEL assay., Results: The combination of aBL (108 J/cm 2 ) with Q-HCL (1 mg/mL) resulted in a significant improvement in the inactivation of C. albicans planktonic cells in vitro, where a 7.04 log 10 colony forming units (CFU) reduction was achieved, compared with aBL alone that only inactivated 3.06 log 10 CFU (P < 0.001) or Q-HCL alone which did not result in a loss of viability. aBL + Q-HCL was also effective at inactivating 48-hour biofilms, with an inactivation 1.73 log 10 CFU at the dose of 108 J/cm 2 aBL and 1 mg/mL Q-HCL, compared with only a 0.73 or 0.66 log 10 CFU by aBL and Q-HCL alone, respectively (P < 0.001). Transmission electron microscopy revealed that aBL + Q-HCL induced morphological and ultrastructural changes consistent with cell wall and cytoplasmic damage. In addition, aBL + Q-HCL was effective at eliminating C. albicans within mouse abrasion wounds, with a 2.47 log 10 relative luminescence unit (RLU) reduction at the dose of 324 J/cm 2 aBL and 0.4 mg/cm 2 Q-HCL, compared with a 1.44 log 10 RLU reduction by aBL alone. Q-HCL or nystatin alone did not significantly reduce the RLU. The TUNEL assay revealed some apoptotic cells before and 24 hours following treatment with aBL + Q-HCL., Conclusion: The combination of aBL + Q-HCL was effective at eliminating C. albicans both in vitro and in vivo. A comprehensive assessment of toxicity (cytotoxicity and genotoxicity) is required to fully determine the safety of aBL + Q-HCL therapy at different doses. In conclusion, the combination of aBL and Q-HCL may be a viable option for the treatment of cutaneous candidiasis. Lasers Surg. Med. © 2019 Wiley Periodicals, Inc., (© 2019 Wiley Periodicals, Inc.)

Background and Objectives: Biofilms cause more than 80% of infections in humans, including more than 90% of all chronic wound infections and are extremely resistant to antimicrobials and the immune system. The situation is exacerbated by the fast spreading of antimicrobial resistance, which has become one of the biggest threats to current public health. There is consequently a critical need for the development of alternative therapeutics. Antimicrobial blue light (aBL) is a light-based approach that exhibits intrinsic antimicrobial effect without the involvement of exogenous photosensitizers. In this study, we investigated the antimicrobial effect of this non-antibiotic approach against biofilms formed by microbial isolates of multidrug-resistant bacteria., Study Design/materials and Methods: Microbial isolates of Acinetobacter baumannii, Candida albicans, Escherichia coli, Enterococcus faecalis, MRSA, Neisseria gonorrhoeae, Pseudomonas aeruginosa, and Proteus mirabilis were studied. Biofilms were grown in microtiter plates for 24 or 48 hours or in the CDC biofilm reactor for 48 hours and exposed to aBL at 405 nm (60 mW/cm 2 , 60 or 30 minutes). The anti-biofilm activity of aBL was measured by viable counts., Results: The biofilms of A. baumannii, N. gonorrhoeae, and P. aeruginosa were the most susceptible to aBL with between 4 and 8 log 10 inactivation after 108 J/cm 2 (60 mW/cm 2 , 30 minutes) or 216 J/cm 2 (60 mW/cm 2 , 60 minutes) aBL were delivered in the microplates. On the contrary, the biofilms of C. albicans, E. coli, E. faecalis, and P. mirabilis were the least susceptible to aBL inactivation (-0.30, -0.24, -0.84, and -0.68 log 10 inactivation, respectively). The same aBL treatment in biofilms developed in the CDC biofilm reactor, caused -1.68 log 10 inactivation in A. baumannii and -1.74 and -1.65 log 10 inactivation in two different strains of P. aeruginosa., Conclusions: aBL exhibits potential against pathogenic microorganisms and could help with the significant need for new antimicrobials in clinical practice to manage multidrug-resistant infections. Lasers Surg. Med. © 2019 Wiley Periodicals, Inc., (© 2019 Wiley Periodicals, Inc.)

The in vitro susceptibilities of Candida albicans and Candida tropicalis to Antimicrobial Photodynamic Treatment with aluminum phthalocyanine chloride in nanoemulsion (ClAlPc/NE) were investigated. PS concentration- and fluence-dependent cell survival after APDT were compared before and after unbound extracellular PS had been washed out. The PS uptake and its subcellular localization were also determined. Exposure to light in the absence of the PS and treatment with the PS in the absence of light did not kill the fungi. APDT with ClAlPc/NE resulted in a reduction of five orders of magnitude in viability for C. albicans and between four and five orders of magnitude for C. tropicalis. Washing the cells to remove unbound PS before light exposure did not impair fungal inactivation, suggesting that cell photosensitization was mainly carried out by cell bound ClAlPc. The degree of ClAlPc uptake was dependent on its concentration. Internalization of ClAlPc by C. albicans and C. tropicalis was confirmed by confocal fluorescence microscopy that showed the PS does not penetrate the nucleus and instead accumulates in specific regions of the cytoplasm. Our results show that incorporating the water-insoluble ClAlPc into a nanoemulsion leads to an efficient formulation capable of photoinactivating both Candida species., (Copyright © 2019 British Mycological Society. Published by Elsevier Ltd. All rights reserved.)

Infectious diseases constitute a serious problem for human health and life. Although many bacterial and fungal infections can be successfully cured by commonly used antibiotics, a new threat emerges in the form of microbial resistance. For this reason, researchers try to find not only new active pharmaceutical ingredients for conventional antibiotherapy but also try to develop new strategies of microbial inactivation. Photodynamic antimicrobial chemotherapy, which relies on reactive oxygen species generated in situ in the presence of a photosensitizer and with the light of an appropriate wavelength, is one of them. Porphyrazines have been considered as potential photosensitizers for anticancer and antimicrobial photodynamic therapy. In this study, three tribenzoporphyrazines with dendrimeric peripheral substituents were subjected to in vitro antimicrobial photocytotoxicity study. One magnesium(II) tribenzoporphyrazine with peripheral 3,5-bis(3,5-dimethoxybenzyloxy)benzylsulfanyl substituents was synthesized and subjected to physicochemical characterization using NMR, UV-Vis, and mass spectrometry techniques. In photochemical studies this molecule revealed moderate singlet oxygen generation ability (Φ ΔDMF  = 0.12, Φ ΔDMSO  = 0.13). The other two magnesium(II) tribenzoporphyrazines applied in the biological study were 4-[3,5-di(hydroxymethyl)phenoxy]butylsulfanyl-substituted tribenzoporphyrazine and 4-[3,5-bis(benzyloxy)benzyloxy]phenyl-substituted tribenzopyrazinoporphyrazine. For the assessment, three microbial strains were chosen: Gram-positive bacteria Staphylococcus aureus ATCC 25923, Gram-negative bacteria Escherichia coli ATCC 25922, and fungal strain Candida albicans ATCC 10231. Very high activity against Staphylococcus aureus at low 10 -6  M concentration was recorded for magnesium(II) tribenzoporphyrazines with peripheral 3,5-bis(3,5-dimethoxybenzyloxy)benzylsulfanyl and 4-[3,5-di(hydroxymethyl)phenoxy]butylsulfanyl substituents with calculated log reductions of 4.4 and 4.8, respectively. It is worth noting that magnesium(II) tribenzoporphyrazine with 4-[3,5-di(hydroxymethyl)phenoxy]butylsulfanyl substituents revealed also 3.2 log reduction in bacterial growth at the concentration 10 -7 M., Competing Interests: Declaration of Competing Interest The authors declare that there is no conflict of interest, (Copyright © 2020 Elsevier B.V. All rights reserved.)

In the pathogenic yeast Candida albicans , the DNA damage response contributes to pathogenicity by regulating cell morphology transitions and maintaining survival in response to DNA damage induced by reactive oxygen species (ROS) in host cells. However, the function of nucleotide excision repair (NER) in C. albicans has not been extensively investigated. To better understand the DNA damage response and its role in virulence, we studied the function of the Rad23 nucleotide excision repair protein in detail. The RAD23 deletion strain and overexpression strain both exhibit UV sensitivity, confirming the critical role of RAD23 in the nucleotide excision repair pathway. Genetic interaction assays revealed that the role of RAD23 in the UV response relies on RAD4 but is independent of RAD53 , MMS22 , and RAD18 RAD4 and RAD23 have similar roles in regulating cell morphogenesis and biofilm formation; however, only RAD23 , but not RAD4 , plays a negative role in virulence regulation in a mouse model. We found that the RAD23 deletion strain showed decreased survival in a Candida -macrophage interaction assay. Transcriptome sequencing (RNA-seq) and quantitative real-time PCR (qRT-PCR) data further revealed that RAD23 , but not RAD4 , regulates the transcription of a virulence factor, SUN41 , suggesting a unique role of RAD23 in virulence regulation. Taking these observations together, our work reveals that the RAD23 -related nucleotide excision pathway plays a critical role in the UV response but may not play a direct role in virulence. The virulence-related role of RAD23 may rely on the regulation of several virulence factors, which may give us further understanding about the linkage between DNA damage repair and virulence regulation in C. albicans IMPORTANCE Candida albicans remains a significant threat to the lives of immunocompromised people. An understanding of the virulence and infection ability of C. albicans cells in the mammalian host may help with clinical treatment and drug discovery. The DNA damage response pathway is closely related to morphology regulation and virulence, as well as the ability to survive in host cells. In this study, we checked the role of the nucleotide excision repair (NER) pathway, the key repair system that functions to remove a large variety of DNA lesions such as those caused by UV light, but whose function has not been well studied in C. albicans We found that Rad23, but not Rad4, plays a role in virulence that appears independent of the function of the NER pathway. Our research revealed that the NER pathway represented by Rad4/Rad23 may not play a direct role in virulence but that Rad23 may play a unique role in regulating the transcription of virulence genes that may contribute to the virulence of C. albicans ., (Copyright © 2020 Feng et al.)

Background and Objectives: Hospital-acquired infections (HAIs) and multidrug resistant bacteria pose a significant threat to the U.S. healthcare system. With a dearth of new antibiotic approvals, novel antimicrobial strategies are required to help solve this problem. Violet-blue visible light (400-470 nm) has been shown to elicit strong antimicrobial effects toward many pathogens, including representatives of the ESKAPE bacterial pathogens, which have a high propensity to cause HAIs. However, phototherapeutic solutions to prevention or treating infections are currently limited by efficient and nonobtrusive light-delivery mechanisms., Study Design/materials and Methods: Here, we investigate the in vitro antimicrobial properties of flexible Corning® light-diffusing fiber (LDF) toward members of the ESKAPE pathogens in a variety of growth states and in the context of biological materials. Bacteria were grown on agar surfaces, in liquid culture and on abiotic surfaces. We also explored the effects of 405 nm light within the presence of lung surfactant, human serum, and on eukaryotic cells. Pathogens tested include Enterococcus spp, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter spp., Staphylococcus epidermidis, Streptococcus pyogenes, Candida albicans, and Escherichia coli., Results: Overall, the LDF delivery of 405 nm violet-blue light exerted a significant degree of microbicidal activity against a wide range of pathogens under diverse experimental conditions., Conclusions: The results exemplify the fiber's promise as a non-traditional approach for the prevention and/or therapeutic intervention of HAIs. Lasers Surg. Med. © 2019 The Authors. Lasers in Surgery and Medicine Published by Wiley Periodicals, Inc., (© 2019 The Authors. Lasers in Surgery and Medicine Published by Wiley Periodicals, Inc.)

A novel hybrid UV-C/microfiltration process for water disinfection is presented, and its application in continuous mode operation to the removal of different pathogen germs (Escherichia coli, Enterococcus faecalis, and Candida albicans) present in urban wastewater. The membrane photoreactor is based on porous stainless steel membranes coated with a TiO 2 layer and illuminated by a UV-C lamp (254 nm). A valve actuator in the outlet of the UV-C stream allows operation of the system under conditions of constant transmembrane pressure (TMP) keeping the UV-C contact time in few seconds, significantly lower than the typical irradiation time employed in TiO 2 photocatalytic processes. An E. coli removal of up to 4-log in the permeate stream and up to 2-log in the UV-C outlet was achieved with a 0.2 μm membrane operating with a TMP of 0.5 bar and a UV-C contact time as low as 8 s. The microbial balance data from the cells recovered from the membrane confirmed that 96-98% of the removed microorganisms died due to the UV-C action over the membrane surface. Modification of the membrane with a TiO 2 layer has been also shown to be a suitable way to improve both the UV-C inactivation and the filtration efficiency. The results reported in this work constitute a proof of concept of the synergy between UV-C and filtration that can be achieved in a hybrid UV-C/microfiltration system, being a good example of process intensification where two products of different quality can be simultaneously obtained.

Gelatin nanoparticles (GN) with an intrinsic antimicrobial activity maybe a good choice to improve the effectiveness of photodynamic antimicrobial chemotherapy (PACT). The aim of this study was to development gelatin nanoparticles loaded methylene blue (GN-MB) and investigate the effect of GN-MB in the Candida albicans growth by PACT protocols. The GN and GN-MB were prepared by two-step desolvation. The nanoparticulate systems were studied by scanning electron microscopy and steady-state techniques, the in vitro drug release was investigated, and we studied the effect of PACT on C. albicans growth. Satisfactory yields and encapsulation efficiency of GN-MB were obtained (yield = 76.0% ± 2.1 and EE = 84.0% ± 1.3). All the spectroscopic results presented here showed excellent photophysical parameters of the studied drug. Entrapment of MB in GN significantly prolongs it's in vitro release. The results of PACT experiments clearly demonstrated that the photosensitivity of C. albicans was higher when GN-MB was used. Gelatin nanoparticles loaded methylene blue-mediated photodynamic antimicrobial chemotherapy may be used against Candida albicans growth.

During symmetry breaking, the highly conserved Rho GTPase Cdc42 becomes stabilized at a defined site via an amplification process. However, little is known about how a new polarity site is established in an already asymmetric cell-a critical process in a changing environment. The human fungal pathogen Candida albicans switches from budding to filamentous growth in response to external cues, a transition controlled by Cdc42. Here, we have used optogenetic manipulation of cell polarity to reset growth in asymmetric filamentous C. albicans cells. We show that increasing the level of active Cdc42 on the plasma membrane results in disruption of the exocyst subunit Sec3 localization and a striking de novo clustering of secretory vesicles. This new cluster of secretory vesicles is highly dynamic, moving by hops and jumps, until a new growth site is established. Our results reveal that secretory vesicle clustering can occur in the absence of directional growth., (Copyright © 2019 The Author(s). Published by Elsevier Inc. All rights reserved.)

Candida albicans is responsible for the majority of nosocomial infections affecting immunocompromised patients. Systemic antifungals may promote microbial resistance, which has led to the search for alternative treatments, such as photothermal therapy (PTT). PTT assumes that the interaction of electromagnetic radiation with a photothermal agent generates heat that can lead to the destruction of tumor cells and the death of microorganisms. Carbon nanotubes (CNTs) have the potential for applications in biomedical systems, including acting as controlled deliverers of drugs, biosensors and scaffolds for tissue engineering and regenerative medicine. Furthermore, the absorption of radiation by CNTs in the infrared region induces an increase in temperature, which makes CNTs candidates for photothermal agents. In this work, the photothermal inactivation of C. albicans was evaluated by multiple wall CNTs associated with laser radiation in the near-infrared region. The mechanisms that are involved in inactivation were evaluated through cell susceptibility studies and an analysis of microscopic images that are associated with mathematical models and fractal concepts. The results indicate that direct contact between the cells and CNTs without irradiation does not lead to cell death, whereas the laser-mediated process is effective in inactivation. The application of the laws of scale and fractal concepts indicate that in the control groups, there are two distinct regimes that are delimited by the mean diameter of the microorganisms, as described by the Eden model and by the quasi-Euclidean surface. For the irradiated groups, the surfaces present only one regime described by Kardar-Parisi-Zhang, KPZ. The analysis of the fractality of the system by mathematical models can help in the identification of new strategies for the inactivation of microorganisms., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Antimicrobial photodynamic inactivation (aPDI) employs the combination of nontoxic photosensitizing dyes and visible light to kill pathogenic microorganisms regardless of drug-resistance, and can be used to treat localized infections. A meso-substituted tetra-methylpyridinium porphyrin with one methyl group replaced by a C12 alkyl chain (FS111) and its Pd-derivative (FS111-Pd) were synthesized and tested as broad-spectrum antimicrobial photosensitizers when excited by blue light (5 or 10 J/cm 2 ). Both compounds showed unprecedented activity, with the superior FS111-Pd giving 3 logs of killing at 1 nM, and eradication at 10 nM for Gram-positive methicillin-resistant Staphylococcus aureus. For the Gram-negative Escherichia coli, both compounds produced eradication at 100 nM, while against the fungal yeast Candida albicans, both compounds produced eradication at 500 nM. Both compounds could be categorized as generators of singlet oxygen (Φ Δ = 0.62 for FS111 and 0.71 for FS111-Pd). An in vivo study was carried out using a mouse model of localized infection in a partial thickness skin abrasion caused by bioluminescent Gram-negative uropathogenic E. coli. Both compounds were effective in reducing bioluminescent signal in a dose-dependent manner when excited by blue light (405 nm), but aPDI with FS111-Pd was somewhat superior both during light and in preventing recurrence during the 6 days following PDT., (© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Candida albicans is a normal flora caused fungal infections and has the ability to form biofilms. The aim of this study was to improve the antifungal effect of silver nanoparticles (AgNPs) and the light source for reducing the biofilm survival of C. albicans. AgNPs were prepared by silver nitrate (AgNO 3 ) and trisodium citrate (Na 3 C 6 H 5 O 7 ). To determine the antifungal effect of treatments on C. albicans biofilm, samples were distributed into four groups; L + P+ was treatment with laser irradiation and AgNPs; L + P- was treatment with laser irradiation only; L - P+ was treatment with AgNPs only (control positive); L - P- was no treatment with laser irradiation or AgNPs (control negative). The growth of fungi had been monitored by measuring the optical density at 405 nm with ELISA reader. The particle size of AgNPs was measured by using (particle size analyzer) and the zeta potential of AgNPs was measured by using Malvern zetasizer. The PSA test showed that the particle size of AgNPs was distributed between 7.531-5559.644 nm. The zeta potentials were found lower than - 30 mV with pH of 7, 9 or 11. The reduction percentage was analyzed by ANOVA test. The highest reduction difference was given at a lower level irradiation because irradiation with a density energy of 6.13 ± 0.002 J/cm 2 resulted in the biofilm reduction of 7.07 ± 0.23% for the sample without AgNPs compared to the sample with AgNPs that increased the biofilm reduction of 64.48 ± 0.07%. The irradiation with a 450-nm light source had a significant fungicidal effect on C. albicans biofilm. The combination of light source and AgNPs provides an increase of biofilm reduction compared to the light source itself.

Objective: The purpose of this in vitro study was to evaluate the antimicrobial effect of activated irrigation with different modes of erbium-doped yttrium aluminum garnet (Er:YAG) laser application on microorganisms related to secondary endodontic infection. Background: Er:YAG laser has been recommended as an adjuvant tool for root canal disinfection during endodontic treatment. Materials and methods: Laser-activated irrigation (LAI) with 300 or 600 μm tips were tested with or without intermittent irrigation with 0.9% sodium chloride (NaCl) solution against different microorganisms (five single strains and dual species ( Streptococcus gordonii combined with Actinomyces oris or Fusobacterium nucleatum ) in root canals after 3 days of incubation. In a 21-day infection model, LAI was used together with intermittent rinsing with sodium hypochlorite (NaOCl) against the dual-species mixtures; here the incidence of microbial regrowth after up to 7 days was monitored. Results: In the 3-day root infection model, LAI protocols did not show any significant reduction of the microbial load when compared with manual irrigation with saline solution. In the 21-day infection, S. gordonii combined with A. oris were not detectable anymore after applying the LAI protocol with a 600 μm tip (30 mJ/10 pps) up to 7 days after treatment. Conclusions: Application of LAI with a 600 μm tip by using an Er:YAG laser might be advantageous in treatment of endodontic infections.

Aims: 1) Evaluation of the photo-thermal (PT) and photo-activated (PAD) antibacterial effect of the 445/970 nm diode laser on E. faecalis, S. aureus and C. albicans mixed biofilms grown together inside root canals of human teeth. 2) Defining a potentially efficient clinical protocol for safe and predictable usage in endodontic procedures., Methodology: The root canals of 100 extracted human teeth with single straight canals were prepared with ProTaper NEXT files, sterilized, contaminated with a combination of three cultures (E. faecalis, S. aureus, C. albicans) and incubated for 15 days. The samples were randomly distributed into three groups (n = 20) and treated as follows: Group 1 (G1) - the 445 nm photo-thermal (PT) effect, Group 2 (G2) - a combination of the 445 nm and 970 nm PT effect, Group 3 (G3) - the 445 nm photo-activated (PAD) effect with 0.1% riboflavin, Group 4 (G4) - a combination of 3% sodium hypochlorite (NaOCl) and the 445 nm PAD effect. Four samples were used as positive control (non-treated) and four as a negative control. 12 aditional samples were used as a control for the G4 (3% NaOCl rinse without the laser). The number of viable microbes in each canal was determined by the colony forming unit (CFU) count., Results: A statistically significant reduction in the microbial population after all treatments was observed (P < 0.001). Groups 2 and 3 showed similar results, both better than Group 1. Group 4 produced the best results., Conclusions: The 445 nm PAD protocol has a stronger antimicrobial effect than the 445 nm PT protocol. Prolonged exposure time to laser light and a combination of wavelengths (445/970 PT protocol) helps in the reduction of microbes. C. albicans appears to be more sensitive to laser irradiation than the other bacteria tested in this study. Following current results, tested laser protocols could be recommended for clinical usage but only as an adjunct to "classic" NaOCl rinse since alone they are not able to completely eradicate all microorganisms., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Objective: The aim of this study was to evaluate the effect of photodynamic therapy (PDT) on multispecies oral caries biofilms composed of Streptococcus mutans , Lactobacillus casei , and Candida albicans . Background: The abovementioned microorganisms largely cause dental caries, especially early childhood caries (ECC), by synthesizing of acids in the presence of sugar. PDT is considered an effective process to remove oral biofilms, and erythrosine, an oral bacterial disclosing agent, is an ideal dye that can be used as a photosensitizer in PDT. However, until now, there are no studies that have reported the effect of erythrosine-mediated PDT on biofilms, including the three microorganisms. Methods: The biofilms were formed on hydroxyapatite discs, and erythrosine was used as the photosensitizer, diluted to a concentration of 40 μM for 3 min. Light was irradiated for 10 and 20 sec using a blue light-emitting diode dental curing light. After the experiment, the colony-forming units of each microbial group cultured on blood agar plates were counted, and a confocal laser-scanning microscope was used to evaluate the effect of PDT. Results: The counts of all three microorganisms significantly decreased in the PDT group compared with those in the control group. For S. mutans and L. casei , there was a larger decrease proportional to the amount of energy irradiated. Conclusions: Overall, PDT showed a significant antimicrobial effect against oral biofilms composed of the three microorganisms, suggesting its potential clinical application for infants with ECC.

Here, we present a protocol to assess the outcomes of per diem red light treatment on the growth of Candida albicans biofilm. To increase the planktonic growth of C. albicans SN425, the inoculums grew on Yeast Nitrogen Base media. For biofilm formation, RPMI 1640 media, which have high concentrations of amino acids, were applied to help biofilm growth. Biofilms of 48 h were treated twice a day for a period of 1 min with a non-coherent light device (red light; wavelength = 635 nm; energy density = 87.6 J·cm -2 ). As a positive control (PC), 0.12% chlorhexidine (CHX) was applied, and as a negative control (NC), 0.89% NaCl was applied to the biofilms. Colony forming units (CFU), dry-weight, soluble and insoluble exopolysaccharides were quantified after treatments. Briefly, the protocol presented here is simple, reproducible and provides answers regarding viability, dry-weight and extracellular polysaccharide amounts after red light treatment.

Phototherapy has been proposed as a direct means of affecting local bacterial infections. However, the use of phototherapy to prevent fungal biofilm development has received comparatively less attention. This study aimed to determine the effects of red light treatment and blue light treatment, without a photosensitizer, on the development of Candida albicans biofilm. During the development of 48-h biofilms of C. albicans SN 425 (n = 10), the biofilms were exposed twice-daily to noncoherent blue and red light (LumaCare; 420 nm and 635 nm). The energy density applied was 72 J cm -2 for blue light and 43.8 J cm 2 , 87.6 J cm 2 , and 175.5 J cm 2 for red light. Positive control (PC) and negative control (NC) groups were treated twice-daily for 1 min with 0.12% chlorhexidine (CHX) and 0.89% NaCl respectively. Biofilms were analyzed for colony forming units (CFU), dry-weight, and exopolysaccharides (EPS-soluble and EPS-insoluble). Data was analyzed by one-way ANOVA and Tukey post hoc test (α = 0.05). Dry-weight was lower than NC (p < 0.001) and approached PC levels with both red and blue light treatments. CFU were also lower in groups exposed to blue light and higher durations of red light (p < 0.05). EPS-soluble and EPS-insoluble measures were variably reduced by these light exposures. In conclusion, twice-daily exposure to both blue and red lights affect the biofilm development and physiology of polysaccharide production and are potential mechanisms for the control of C. albicans biofilm matrix development.

Candida albicans is a predominant cause of fungal infections in mucosal tissues as well as life-threatening bloodstream infections in immunocompromised patients. Within the human body, C. albicans is mostly embedded in biofilms, which provides increased resistance to antifungal drugs. The glyoxalase Glx3 is an abundant proteomic component of the biofilm extracellular matrix. Here, we document phenotypic studies of a glx3Δ null mutant concerning its role in biofilm formation, filamentation, antifungal drug resistance, cell wall integrity and virulence. First, consistent with its function as glyoxalase, the glx3 null mutant showed impaired growth on media containing glycerol as the carbon source and in the presence of low concentrations of hydrogen peroxide. Importantly, the glx3Δ mutant showed decreased fitness at 37°C and formed less biofilm as compared to wild type and a reintegrant strain. At the permissive temperature of 28°C, the glx3Δ mutant showed impaired filamentation as well as increased sensitivity to Calcofluor white, Congo red, sodium dodecyl sulfate and zymolyase, indicating subtle alterations in wall architecture even though gross quantitative compositional changes were not detected. Interestingly, and consistent with its impaired filamentation, biofilm formation and growth at 37°C, the glx3Δ mutant is avirulent. Our results underline the role of Glx3 in fungal pathogenesis and the involvement of the fungal wall in this process.

The purpose of this study was to evaluate the effects of Nd:YAG laser with flat-top handpiece on the in vitro growth of Candida albicans and Streptococcus mutans. The incidence of C. albicans (opportunistic commensal) and S. mutans (facultatively anaerobic) infections is increasing, despite available treatments. Cultures of Streptococcus mutans and Candida albicans were irradiated using Nd:YAG laser (LightWalker, Fotona) with flat-top handpiece (Genova, LightWalker, Fotona) at the following parameters: group G1: 0.25 W, 10 Hz, 15 s, 3 J and group G2: 1 W, 10 Hz, 60s, 59 J. The results were evaluated directly and 24 h after irradiation using a quantitative culture method (estimation of colony-forming units in 1 ml of suspension, cfu/ml), and microscopic analysis with Janus green stain and compared with control group in which laser was not applied. C. albicans was reduced by 20 up to 54% for G1, and for G2 by 10 up to 60% directly after the application. The cfu/ml values for S. mutans decreased by 13% (p = 0.1771) for G1 and 89% (p < 0.0001) for G2. In both test groups 24 h after the application, the number of colony-forming units decreased by 15-46% for G1 and by 15-64% for G2. The arrested cell division, increasing the surface area and increasing the number of metabolically inactive cells, were observed in morphometric analysis. Macroscopic and microscopic analyses revealed a reduction in cell number and a significant decrease of cell metabolism after laser application for both C. albicans and S. mutans.

We have analysed the role of homologous recombination (HR) genes on the repair of double-strand breaks induced by γ-ionising radiation in Candida albicans. Depletion of either CaRad51 or CaRad52 caused a dramatic drop in the number of survivors compared with wild type, whereas depletion of CaRad59 caused a moderate decrease. Besides, compared with Saccharomyces cerevisiae, C. albicans relies more on HR proteins for repair of ionising radiation lesions. Pulse-field electrokaryotypes of survivors identified genetic alterations mainly in the form of aneuploidy in HR mutants and chromosome length polymorphism and ectopic translocation in wild type. Increasing irradiation (4 to 80 krad) of both cycling and nocodazole-treated (G2/M-arrested) cells revealed a gradual loss of chromosomes, larger chromosomes being more affected than smaller ones. For cycling wild-type cells, shattered chromosomes were progressively restored following incubation in yeast extract, peptone, dextrose medium, but not in phosphate-buffered saline, and this accompanied by a moderate increase in colony-forming units, suggesting that repair was followed by replication of survivors. Irradiated G2/M arrested cells from wild type but not from HR mutants partially restored the chromosome ladder following incubation (4-8 hr) in yeast peptone dextrose-nocodazole. However, HR mutants showed a chromosome shattering pattern similar to wild type, an indication that lesions other than double-strand breaks, likely single-strand break, are responsible for their drastically reduced survivability., (© 2018 John Wiley & Sons Ltd.)

A new fullerene (BB4-PPBA) functionalized with a tertiary amine and carboxylic acid was prepared and compared with BB4 (cationic quaternary group) for antimicrobial photodynamic inactivation (aPDI). BB4 was highly active against Gram-positive methicillin resistant Staphylococcus aureus (MRSA) and BB4-PPBA was moderately active when activated by blue light. Neither compound showed much activity against Gram-negative Escherichia coli or fungus Candida albicans. Therefore, we examined potentiation by addition of potassium iodide. Both compounds were highly potentiated by KI (1-6 extra logs of killing). BB4-PPBA was potentiated more than BB4 against MRSA and E. coli, while for C. albicans the reverse was the case. Addition of azide potentiated aPDI mediated by BB4 against MRSA, but abolished the potentiation caused by KI with both compounds. The killing ability after light decayed after 24 h in the case of BB4, implying a contribution from hypoiodite as well as free iodine. Tyrosine was readily iodinated with BB4-PPBA plus KI, but less so with BB4. We conclude that the photochemical mechanisms of these two fullerenes are different. BB4-PPBA is more Type 2 (singlet oxygen) while BB4 is more Type 1 (electron transfer). There is also a possibility of direct bacterial killing by electron transfer, but this will require more study to prove., (Copyright © 2018. Published by Elsevier B.V.)

This paper reports the synthesis of silver oxide (Ag 2 O) and moxifloxacin functionalized silver oxide (M-Ag 2 O) nanoparticles for photocatalytic and antimicrobial activity. The Ag 2 O nanoparticles were synthesized by using 2 dimethyl amino ethanol as reducing agent. The BET surface area measured from N 2 adsorption method was found to be 16.89 m 2 /g. The mix (cubic and hexagonal) phase of silver oxide (Ag 2 O) nanoparticles was confirmed by X-rays diffraction (XRD). The extra diffracted peaks were observed after moxifloxacin fictionalization. The scanning electron micrographs display spherical shaped particles of different sizes. The elemental composition and weight percent of both samples were studied by energy dispersive X-ray (EDX). The decrease in the weight percent of silver with the subsequent increase in the weight percent of carbon and oxygen revealed the successful loading of moxifloxacin onto Ag 2 O NPs. The two stages of weight loss due to the removal of physisorbed and chemisorbed water was examined during thermogravimetric analysis (TGA). The optical band gap derived from the diffuse reflectance spectrum (DRS) was 1.83 eV, which corresponds to the transmittance edge of 676 nm. The Fourier transform infrared (FTIR) band at 668.56 cm -1 confirms the successful synthesis of moxifloxacin functionalized silver oxide (Ag 2 O) nanoparticles. The pure Ag 2 O nanoparticles were used for the degradation of rhodamine 6G and 98.56% dye was degraded in 330 min. The bacterial species selected for the present study were Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Candida albicans and Aspergillus Niger. Both pure and functionalized Ag 2 O NPs were screened against selected bacterial and fungal species and they showed improved activity with the volume of samples taken in wells. However, the activity of Ag 2 O NPs against fungi was found less effective than bacteria which may be due to the difference in the composition of the cell wall. Further gram-positive bacteria showed more resistance toward both samples as compared to the gram-negative bacteria. It was concluded that Ag 2 O NPs upon conjugation with moxifloxacin displayed promising antimicrobial activity., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Antimicrobial photodynamic therapy (aPDT) has been proposed as an alternative method for oral candidiasis (OC), while nanocarriers have been used to improve the water solubility of curcumin (CUR). The aim of this study is to encapsulate CUR in polymeric nanoparticles (NPs) and to evaluate its photodynamic effects on a murine model of OC. Anionic and cationic CUR-NP is synthesized using poly-lactic acid and dextran sulfate and then characterized. Female mice are immunosuppressed and inoculated with Candida albicans (Ca) to induce OC. aPDT is performed by applying CUR-NP or free CUR on the dorsum of the tongue, followed by blue light irradiation for five consecutive days. Nystatin is used as positive control. Afterward, Ca are recovered and cultivated. Animals are euthanized for histological, immunohistochemical, and DNA damage evaluation. Encapsulation in NP improves the water solubility of CUR. Nystatin shows the highest reduction of Ca, followed by aPDT mediated by free CUR, which results in immunolabelling of cytokeratins closer to those observed for healthy animals. Anionic CUR-NP does not show antifungal effect, and cationic CUR-NP reduces Ca even in the absence of light. DNA damage is associated with Ca infection. Consecutive aPDT application is a safe treatment for OC.

Candida albicans is an opportunistic pathogen commensal in the oral cavity, vagina, and healthy skin. Common therapeutic options for fungal infections are topical or systemic antifungal drugs. Recently, in cutaneous pathologies, lasers and light-based treatments have emerged showing few contraindications and minimal side effects. The Q-switched (Nd-YAG) laser at a wavelength of 1064 nm has been shown to be useful in dermatology, dentistry, and some other medical specialties. It is used to treat onychomycoses, warts, and wounds and in some other treatments. We analyzed the effect of Q-switched (Nd-YAG) laser 1064 nm on human keratinocytes infected with C. albicans. In particular, we evaluated the effect of laser on invasiveness of C. albicans and on inflammatory and protective response of HaCaT cells infected. The results obtained did not show inhibitory, fungicidal, or fungistatic effects of laser on yeast; in addition, laser did not affect HaCaT vitality. HaCaT cells infected with C. albicans and irradiated with laser showed a reduction of invasiveness of TNF-α and IL8 gene expression and an increase of immunomodulatory cytokines such as TGFβ. Furthermore, laser induces a significant over-expression of HSP70B (heat shock protein) and of HBD-2 (Human β defensin-2) in HaCaT infected with C. albicans, compared to the untreated control. The use of Q-switched Nd:YAG laser in skin mycosis caused by C. albicans reduces yeast invasiveness in keratinocytes, downregulates inflammatory activities, and facilitates cytoprotection and antimicrobial defense. Our results offer a promising therapeutic strategy in the management of skin candidiasis, also in combination with conventional therapies.

It is shown that exposure of suspensions of gram-positive Staphylococcus aureus, gram-negative Escherichia coli and yeast-like fungi Candida albicans to laser radiation of blue spectral region with 405 and 445 nm causes their growth inhibition without prior addition of exogenous photosensitizers. It is experimentally confirmed that compounds of flavin type capable of sensitizing the formation of reactive oxygen species can act as acceptors of optical radiation of blue spectral region determining its antimicrobial effect along with endogenous metal-free porphyrins (the role of endogenous porphyrins has been confirmed earlier by a number of researchers). The participation of these compounds in the antimicrobial effect of laser radiation is supported by the registration of porphyrin and flavin fluorescence in extracts of microbial cells upon excitation by radiation used to inactivate the pathogens. In addition, the intensity of the porphyrin fluorescence in extracts of microbial cells in the transition from radiation with λ = 405 nm to radiation with λ = 445 nm decreases by 15-30 times, whereas the photosensitivity of the cells under study in this transition decreases only 3.7-6.2 times. The contribution of porphyrin photosensitizers is most pronounced upon exposure to radiation with λ = 405 nm (absorption maximum of the Soret band of porphyrins), and flavins - upon exposure to radiation with λ = 445 nm (maximum in the flavin absorption spectrum and minimum in the absorption spectrum of porphyrins). The ratio between the intensity of the porphyrin and flavin components in the fluorescence spectrum of extracts depends on the type of microbial cells., (Copyright © 2018 Elsevier B.V. All rights reserved.)

It is difficult to effectively eradicate C. albicans using traditional antifungal agents, mainly because the low permeability of the C. albicans cell wall creates strong drug resistance. The aim of this study was to investigate the synergistic fungicidal effect and the underlying mechanisms of low-frequency and low-intensity ultrasound combined with a treatment of amphotericin B-loaded nanoparticles (AmB-NPs) against C. albicans. AmB-NPs were prepared by a poly(lactic-co-glycolic acid) (PLGA) double emulsion method. C. albicans was treated by AmB-NPs combined with 42 kHz ultrasound irradiation at an intensity of 0.30 W/cm 2 for 15 min. The results demonstrate that the application of ultrasound enhanced the antibacterial effectiveness of AmB-NPs (P < 0.01), and the antifungal efficiency increased significantly with increasing AmB concentration of drug-loaded nanoparticles under ultrasonic irradiation. Additionally, the mycelial morphology of C. albicans suffered from the most severe damage and loss of normal microbial morphology after the combined treatment of AmB-NPs and ultrasound, as revealed by electron microscope. Furthermore, we verified the safe use of low-frequency ultrasound on exposed skin and discussed the potential mechanism of ultrasound enhanced fungicidal activity. The results reveal that the mechanism may be associated with the ultrasound cavitation effect and an increase in intracellular reactive oxygen species., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Photodynamic inactivation (PDI) has been shown to be a potential treatment modality against Candida infection. However, limited light penetration might leave some cells alive and undergoing regrowth. In this study, we explored the possibility of combining PDI and antifungal agents to enhance the therapeutic efficacy of Candida albicans and drug-resistant clinical isolates. We found that planktonic cells that had survived toluidine blue O (TBO)-mediated PDI were significantly susceptible to fluconazole within the first 2 h post PDI. Following PDI, the killing efficacy of antifungal agents relates to the PDI dose in wild-type and drug-resistant clinical isolates. However, only a 3-log reduction was found in the biofilm cells, suggesting limited therapeutic efficacy under the combined treatment of PDI and azole antifungal drugs. Using confocal microscopic analysis, we showed that TBO-mediated PDI could partially remove the extracellular polymeric substance (EPS) of biofilm. Finally, we showed that a combination of PDI with caspofungin could result in the complete killing of biofilms compared to those treated with caspofungin or PDI alone. These results clearly indicate that the combination of PDI and antifungal agents could be a promising treatment against C. albicans infections., Competing Interests: The authors declare no conflict of interest.

Candida albicans is the most commonly encountered human fungal pathogen, and it is traditionally treated with antimicrobial chemical agents. The antimicrobial effect of these agents is largely weakened by drug resistance and biofilm-associated virulence. Enhancement of the antimicrobial activity of existing agents is needed for effective candidiasis treatment. Our aim was to develop a therapy that combined biofilm disruption with existing antimicrobial agents. Photodynamic therapy (PDT) utilizing curcumin and blue light was tested as an independent therapy and in combination with fluconazole treatment. Viability assays and morphology analysis were used to assess the effectiveness of C. albicans treatment. Results showed that fluconazole treatment decreased the viability of planktonic C. albicans , but the decrease was not as pronounced in adherent C. albicans because its biofilm form was markedly more resistant to the antimicrobiotic. PDT effectively eradicated C. albicans biofilms, and when combined with fluconazole, PDT significantly inhibited C. albicans to a greater extent. This study suggests that the addition of PDT to fluconazole to treat C. albicans infection enhances its effectiveness and can potentially be used clinically., Competing Interests: The authors declare no conflict of interest.

Background: Ultraviolet irradiation is effectively used as a disinfection method for inactivating microorganisms. Methods: We investigated the bactericidal effects by irradiation with a deep-ultraviolet light-emitting diode (DUV-LED) on the causative microorganisms of catheter related blood stream infection contaminating the solution for intravenous infusion. For irradiation, prototype modules for water disinfection with a DUV-LED were used. Experiments were conducted on five kinds of microorganisms. We examined the dependence of bactericidal action on eleven solutions. Administration sets were carried out three types. Results: When the administration set JY-PB343L containing the infusion tube made of polybutadiene was used, the bactericidal action of the DUV-LED against all tested microorganisms in the physiological saline solutions was considered to be effective. We confirmed that the number of viable bacteria decreased in 5% glucose solution and electrolyte infusions with DUV-LED irradiation. Conclusions: These results indicate that the DUV-LED irradiation has bactericidal effects in glucose infusion and electrolyte infusions by irradiating via a plasticizer-free polybutadiene administration set. We consider DUV-LED irradiation to be clinically applicable., Competing Interests: Competing Interests: The authors have declared that no competing interest exists.

The aim of the present study was to evaluate, in vitro, the effect of different pre-irradiation times of the photosensitizer in photodynamic therapy in biofilms formed by Streptococcus mutans and Candida albicans, through the evaluation of the microbial load. The factors under study were as follows: times of pre-irradiation of the photosensitizer in three levels (1, 2, or 5 min). For the control of the cariogenic dental biofilm with antimicrobial photodynamic therapy (aPDT), methylene blue (0.01%) was used in association with the diode laser (InGaAlP) with a wavelength of 660 nm. Chlorhexidine digluconate (0.12% CHX) and saline were used as positive and negative controls, respectively. The study design was carried out in complete and randomized blocks. The sample consisted of 15 S. mutans biofilms cultures, randomly divided into five groups and 15 C. albicans cultures, also divided into five groups. The experiment was performed in triplicate (n = 3) and the response variables were obtained through quantitative analysis of bacterial viability, expressed in colony-forming units (CFU) per square millimeter of the specimen area. The data were analyzed with the aid of the ANOVA one-way test and Tukey's post-test. All analyses were performed using the Graph Pad Prism 4.0 program, with a significance level of 5%. For the S. mutans group, only the saline solution presented a statistically significant difference when compared to the other treatments (p < 0.05), that is, the treatment with aPDT, irrespective of the irradiation time applied, was similar to the treatment with CHX and both were more effective in reducing cariogenic biofilm compared to saline. For the group of C. albicans, there was no statistical difference between the groups (p > 0.05). Therefore, it can be concluded that the treatment with aPDT reduced the number of CFUs of S. mutans in a similar way to CHX, independently of the pre-irradiation time applied. No effect of this therapy or of the different pre-irradiation times on the C. albicans biofilm could be observed. In this way, the pre-irradiation time of 1 min can be used to reduce the microbial load of S. mutans.

Photodynamic inactivation (PDI) has been reported to be effective to eradicate a wide variety of pathogens, including antimicrobial-resistant microorganisms. The aim of this study was to identify the potential molecular targets of PDI depending on growth phase of Candida albicans. Fungal cells in lag (6h) and stationary (48h) phases were submitted to PDI mediated by methylene blue (MB) combined with a (662±21) nm-LED, at 360mW of optical power. Pre-irradiation time was 10min and exposure times were 12min, 15min and 18min delivering radiant exposures of 129.6J/cm 2 , 162J/cm 2 and 194.4J/cm 2 , respectively, on a 24-well plate of about 2cm 2 at an irradiance of 180mW/cm 2 . Scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force spectroscopy (AFS) and Fourier transform infrared spectroscopy (FT-IR) were employed to evaluate the photodynamic effect in young and old fungal cells following 15min of irradiation. Morphological analysis revealed wrinkled and shrunk fungal cell membrane for both growth phases while extracellular polymeric substance (EPS) removal was only observed for old fungal cells. Damaged intracellular structures were more pronounced in young fungal cells. The surface nanostiffness of young fungal cells decreased after PDI but increased for old fungal cells. Cellular adhesion force was reduced for both growth phases. Fungal cells in lag phase predominantly showed degradation of nucleic acids and proteins, while fungal cells in stationary phase showed more pronounced degradation of polysaccharides and lipids. Taken together, our results indicate different molecular targets for fungal cells in lag and stationary growth phase following PDI., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Photodynamic Inactivation (PDI) is based on the use of a photosensitizer (PS) and light that results mainly in the production of reactive oxygen species, aiming to produce microorganism cell death. PS incubation time and light dose are key protocol parameters that influence PDI response; the correct choice of them can increase the efficiency of inactivation. The results of this study show that a minor change in the PDI protocol, namely light-driven incubation leads to a higher photosensitizer and more uniform cell uptake inside the irradiated zone. Furthermore, as the uptake increases, the damage caused by PDI also increases. The proposed light-driven incubation prior to the inactivation illumination dose has advantages when compared to the traditional PDI treatments since it can be more selective and effective. Using a violet light as pre-illumination (light-driven incubation) source and a red-light system as PDI source, it was possible to demonstrate that when compared to the traditional protocol of dark incubation, the pre-illuminated cell culture showed an inactivation increase of 7 log units. These in vitro results performed in Candida albicans cells may result in the introduction of a new protocol for PDI., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The impact of substituents on the photochemical and biological properties of tetraphenylporphyrin-based photosensitizers for photodynamic therapy of cancer (PDT) as well as photodynamic inactivation of microorganisms (PDI) was examined. Spectroscopic and physicochemical properties were related with therapeutic efficacy in PDT of cancer and PDI of microbial cells in vitro. Less polar halogenated, sulfonamide porphyrins were most readily taken up by cells compared to hydrophilic and anionic porphyrins. The uptake and PDT of a hydrophilic porphyrin was significantly enhanced with incorporation in polymeric micelles (Pluronic L121). Photodynamic inactivation studies were performed against Gram-positive (S. aureus, E. faecalis), Gram-negative bacteria (E. coli, P. aeruginosa, S. marcescens) and fungal yeast (C. albicans). We observed a 6 logs reduction of S. aureus after irradiation (10 J/cm2) in the presence of 20 μM of hydrophilic porphyrin, but this was not improved with incorporation in Pluronic L121. A 2-3 logs reduction was obtained for E. coli using similar doses, and a decrease of 3-4 logs was achieved for C. albicans. Rational substitution of tetraphenylporphyrins improves their photodynamic properties and informs on strategies to obtain photosensitizers for efficient PDT and PDI. However, the design of the photosensitizers must be accompanied by the development of tailored drug formulations.

A promising approach for the eradication of biofilm formed by the yeast Candida albicans seems to be photodynamic inactivation (PDI). This work presents a use of methylene blue (MB, 1 mM) irradiated with a red laser (output power 190 mW/cm2, wavelength 660 nm) for the eradication of a biofilm formed by the fluconazole-resistant (FLC-resistant) strain C. albicans CY 1123 compared to the standard strain C. albicans SC5314. The periods of irradiation corresponded to the fluence of 15, 23 and 57 J/cm2. Effectiveness of PDI was evident with following percentage of survived biofilm cells: 24.57, 23.46, and 22.29% for SC5314 and 40.28, 17.91, and 5.89% for CY 1123, respectively, compared to the samples without irradiation. Light and confocal laser scanning microscopy confirmed the effectiveness of PDI. However, the morphological form of C. albicans seems to play an important role as well, since prolonged duration of irradiation did not increase efficiency of PDI on C. albicans SC5314. An experiment with the yeast-to-hyphae transition revealed that the FLC-resistant strain expressed a markedly reduced capacity to form hyphae compared to SC5314. We summarized that PDI was effective on biofilm formed by the FLC-resistant strain, but resistance most likely did not play significant role in PDI. Additionally, we observed differences in susceptibility to PDI between biofilms composed of the mycelia and only of the yeasts, and finally, the employment of a laser in PDI enabled a decreasing period of irradiation while maintaining the high effectiveness of PDI., (© The Author 2016. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Candida spp. are able to survive on hospital surfaces and causes healthcare-associated infections (HCAIs). Since surface cleaning and disinfecting interventions are not totally effective to eliminate Candida spp., new approaches should be devised. Copper (Cu) has widely recognized antifungal activity and the use of Cu-sputtered surfaces has recently been proposed to curb the spread of HCAIs. Moreover, the activity of Cu under the action of actinic light remains underexplored. We investigated the antifungal activity of Cu-sputtered polyester surfaces (Cu-PES) against azole-resistant Candida albicans and Candida glabrata under dark and low intensity visible light irradiation (4.65mW/cm 2 ). The surface properties of Cu-PES photocatalysts were characterized by diffuse reflectance spectroscopy (DRS) and X-ray fluorescence (XRF). Under dark, Cu-PES showed a fungicidal activity (≥3log 10 CFU reduction of the initial inoculum) against both C. albicans DSY296 and C. glabrata DSY565 leading to a reduction of the starting inoculum of 3.1 and 3.0log 10 CFU, respectively, within 60min of exposure. Under low intensity visible light irradiation, Cu-PES exhibited an accelerated fungicidal activity against both strains with a reduction of 3.0 and 3.4log 10 CFU, respectively, within 30min of exposure. This effect was likely due to the semiconductor Cu 2 O/CuO charge separation. The decrease in cell viability of the two Candida strains under dark and light conditions correlated with the progressive loss of membrane integrity. These results indicate that Cu-PES represent a promising strategy for decreasing the colonization of surfaces by yeasts and that actinic light can improve its self-disinfecting activity., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Candida albicans is responsible for many of the infections affecting immunocompromised individuals. Although most C. albicans are susceptible to antifungal drugs, uncontrolled use of these drugs has promoted the development of resistance to current antifungals. The clinical implication of resistant strains has led to the search for safer and more effective drugs as well as alternative approaches, such as controlled drug release using liposomes and photodynamic inactivation (PDI), to eliminate pathogens by combining light and photosensitizers. In this study, we used layer-by-layer (LBL) assembly to immobilize triclosan and acridine orange encapsulated in liposomes and investigated the possibility of controlled release using light. Experiments were carried out to examine the susceptibility of C. albicans to PDI. The effects of laser irradiation were investigated by fluorescence microscopy, atomic force microscopy, and release kinetics. Liposomes were successfully prepared and immobilized using the self-assembly LBL technique. Triclosan was released more quickly when the LBL film was irradiated. The release rate was approximately 40% higher in irradiated films (fluence of 15J/cm 2 ) than in non-irradiated films. The results of the susceptibility experiments and surface morphological analysis indicated that C. albicans cell death is caused by photodynamic inactivation. Liposomes containing triclosan and acridine orange may be useful for inactivating C. albicans using light. Our results lay the foundation for the development of new clinical strategies to control resistant strains., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Photodynamic therapy (PDT) is a promising treatment for oral candidoses. Its use as an alternative to antifungals prevents several adverse effects, including microbial resistance. However, most PDT protocols do not employ devices and consumables commonly available in dental practice, thus influencing treatment affordability. This study aimed to determine the efficacy of a PDT method based on light curing units' blue LEDs combined to a plaque-disclosing composition (5% erythrosine) against C. albicans in culture and in a murine model of oral candidosis. Standard and resistant fungal strains were tested in vitro in planktonic and biofilm forms. PDT (pre-irradiation time periods: 30 and 60 s; irradiation time: 3 min) was compared to control conditions without light and/or erythrosine. Mice with induced oral candidosis (n = 40) randomly received PDT or similar control conditions with subsequent C. albicans count. These mice underwent histological analysis, as well as 12 healthy mice submitted to experimental treatments. PDT completely inactivated C. albicans planktonic cells and biofilm. Control conditions presented minor differences (ANOVA, p < 0.05), with mean values ranging from 5.2 to 6.8 log10 (UFC/mL). Infected mice presented no significant difference in C. albicans counts consequent to treatments (ANOVA, p = 0.721), although the PDT protocol was able to enhance the inflammatory infiltrate in healthy mice. It can be concluded that the tested PDT protocol can inactivate C. albicans but still needs further investigation in order to achieve efficacy and safety.

Objective: The objective was to compare the efficacy of three different lasers in disinfection of root canals inoculated with Enterococcus faecalis and Candida albicans biofilms., Background: Endodontic space disinfection depends on the type of root canal irrigant used and the way it is delivered and agitated because irrigants have limited ability to reach all parts of root canal system., Materials and Methods: Thirty single-rooted human teeth were selected. Root canals were instrumented and root surfaces were sealed using adhesive and the apical openings with adhesive and composite resin. Roots were fixed in Eppendorf tubes and sterilized in autoclave. The specimens were randomly divided into three experimental groups (n = 10) and inoculated with E. faecalis and C. albicans. After 7 days of incubation period, the number of E. faecalis and C. albicans colony-forming units (CFUs) was determined for each root canal. In the first experimental group, Er:YAG laser (0.3 W) with photon-induced photoacoustic streaming technique was used for root canal disinfection, in the second, Nd:YAG laser (1.5 W), and in the third, Er,Cr:YSGG (1.25 W) laser was used. After different root canal disinfection protocols, the number of E. faecalis and C. albicans CFUs was determined again for each root canal., Results: Er:YAG and Er,Cr:YSGG lasers eradicated significant number of E. faecalis and C. albicans CFUs (p < 0.05), while Nd:YAG laser irradiation did not result in statistically significant reduction (p > 0.05). Er,Cr:YSGG laser eradicated significantly more microorganisms in comparison with Er:YAG laser (p < 0.05)., Conclusions: Er,Cr:YSGG laser was the most efficient tool in eradication of E. faecalis and C. albicans biofilms.

Background: Studies on photodynamic inactivation against microorganisms had a great development in recent years. The aim of this work was to test the application of different laser wavelengths with or without different photosensitizing dyes on Candida albicans cells in vitro and in photodynamic therapy protocols in vivo in larvae of Galleria mellonella., Methods: Laser application was realized on C. albicans cells suspended in saline solution or cultured on solid medium for the in vitro study, and in a model of G. mellonella candidal infection for the in vivo study. Three wavelengths (650, 405, and 532nm) were used in continuous mode with different values of applied fluences: 10, 20 and 30J/cm 2 for the in vitro study and 10J/cm 2 for the in vivo study, without and with photosensitizing dyes., Results: No growth inhibition was obtained on yeast cells in saline solution without photosensitizers. The maximum inhibition of growth (100%) was obtained with 405nm diode laser and curcumin at any used fluence. No growth inhibition was observed for yeast cells cultured on solid medium after laser application without dyes. An inhibition was observed after laser application when curcumin and erythrosine were added to the medium. The survival curves of G. mellonella larvae infected with C. albicans with or without the different dyes and after laser application showed a statistically significant difference (p<0.001) in comparison with the proper control groups., Conclusions: These results show the efficacy of photodynamic inactivation exploiting a suitable combination of light and dyes against C. albicans and the potential of photodynamic therapy for the treatment of candidal infections., (Copyright © 2017 Elsevier B.V. All rights reserved.)

The aims of this study were to evaluate the effectiveness of different microwave radiation regimens for disinfection of type IV dental stone surfaces and to assess the influence of these regimens on surface roughness and dimensional change following disinfection. Three hundred cylindrical (20 × 2-mm) test specimens were made in type IV stone and divided into subgroups of 20 according to the microorganisms tested (Staphylococcus aureus, Escherichia coli, or Candida albicans) and the 900-W microwave radiation protocol (cycles of 3, 5, or 7 minutes; a positive control; or a negative control). To test physical changes, 80 test specimens were made with the same dimensions except that they had 2 parallel and symmetrical indentations measuring 8 × 4 mm. These specimens were divided into 4 subgroups of 20 each (a subgroup for each radiation time and a negative control). The mean dimensional change and roughness data were analyzed by mixed models for repeated measures and Tukey-Kramer tests. Disinfection was analyzed with descriptive statistics. For E coli and C albicans, all radiation times proved effective at sterilizing the test specimens. For S aureus, sterilization was achieved with 5 and 7 minutes of exposure; however, colonies were observed in 10 Petri dishes (50%) exposed to 3 minutes of microwave radiation. No statistically significant difference in dimensional change or surface roughness was observed for any radiation regimen (P > 0.05).

Two cationic BODIPYs 3 and 4 were synthesized by acid-catalyzed condensation of the corresponding pyrrole and benzaldehyde, followed by complexation with boron and methylation. Compound 3 contains methyl at the 1,3,5 and 7 positions of the s-indacene ring and a N,N,N-trimethylamino group attached to the phenylene unit, while 4 is not substituted by methyl groups and the cationic group is bound by an aliphatic spacer. UV-visible absorption spectra of these BODIPYs show an intense band at ∼500 nm in solvents of different polarities and n-heptane/sodium bis(2-ethylhexyl)sulfosuccinate (AOT)/water reverse micelles. Compound 3 exhibits a higher fluorescence quantum yield (Φ F  = 0.29) than 4 (Φ F  = 0.030) in N,N-dimethylformamide (DMF) due to sterically hindered rotation of the phenylene ring. BODIPYs 3 and 4 induce photosensitized oxidation of 1,3-diphenylisobenzofuran (DPBF) with yields of singlet molecular oxygen of 0.07 and 0.03, respectively. However, the photodynamic activity increases in a microheterogenic medium formed by AOT micelles. Also, both BODIPYs sensitize the photodecomposition of l-tryptophan (Trp). In presence of diazabicyclo[2.2.2]octane (DABCO) or D-mannitol, a reduction in the photooxidation of Trp was found, indicating a contribution of type I photoprocess. Moreover, the addition of KI produces fluorescence quenching of BODIPYs and reduces the photooxidation of DPBF. In contrast, this inorganic salt increases the photoinduced decomposition of Trp, possibly due to the formation of reactive iodine species. The effect of KI was also observed in the potentiation of the photoinactivation of microorganisms. Therefore, the presence of KI could increase the decomposition of biomolecules induced by these BODIPYs in a biological media, leading to a higher cell photoinactivation., (Copyright © 2016 Elsevier Masson SAS. All rights reserved.)