RESUMEN

OBJECTIVES: Photodynamic inactivation (PDI) is a powerful technique for eradicating microorganisms, and our group previously demonstrated its effectiveness against planktonic cultures of Staphylococcus aureus bacteria using 5,10,15,20-tetrakis[4-(3-N,N-dimethylaminopropoxy)phenyl]porphyrin (TAPP) and visible light irradiation. However, biofilms exhibit a lower sensitivity to PDI, mainly due to limited penetration of the photosensitizer (PS). In the context of emerging antibacterial strategies, near-infrared treatments (NIRTs) have shown promise, especially for combating resistant strains. NIRT can act either through photon absorption by water, causing a thermal effect on bacteria, or by specific chromophores without a significant temperature increase. Our objective was to enhance biofilm sensitivity to TAPP-PDI by pretreatment with NIRT. This combined approach aims to disrupt biofilms and increase the efficacy of TAPP-PDI against bacterial biofilms. MATERIALS AND METHODS: In vitro biofilm models of S. aureus RN6390 were utilized. NIRTs involved a 980 nm laser (continuous mode, 7.5 W/cm2, 30 s, totaling 225 J/cm2) post-TAPP exposure to enhance photosensitizer accumulation. Subsequent visible light irradiation at 180 J/cm2 was employed to perform PDI. Colony-forming unit counts evaluated the synergistic effect on bacterial viability. Scanning electron microscopy visualized the architectural changes in the biofilm structure. TAPP was extracted from bacteria to estimate the impact of NIRT on biofilm penetration. RESULTS: Using in vitro biofilm models, NIRT application following biofilm exposure to TAPP increased PS accumulation per bacteria. Under these conditions, NIRT induced a transient increase in the temperature of PBS to 46.0 ± 2.6°C (ΔT = 21.5°C). Following exposure to visible light, a synergistic effect emerged, yielding a substantial 4.4 ± 0.1-log CFU reduction. In contrast, the PDI and NIRT treatments individually caused a decrease in viability of 0.9 ± 0.1 and 0.8 ± 0.2-log respectively. Interestingly, preheating TAPP-PBS to 46°C had no significant impact on TAPP-PDI efficacy, suggesting the involvement of thermal and nonthermal effects of NIR action. In addition to the enhanced TAPP penetration, NIRT dispersed the biofilms and induced clefts in the biofilm matrix. CONCLUSION: Our findings suggest that NIR irradiation serves as a complementary treatment to PDI. This combined strategy reduces bacterial numbers at lower PS concentrations than standalone PDI treatment, highlighting its potential as an effective and resource-efficient antibacterial approach.

Asunto(s)

RESUMEN

This study aimed to assess the impact of adaptation of ten strains of O157:H7 and non-O157 Escherichia coli to low pH (acid shock or slow acidification) and the effects of this exposure or not on the resistance of E. coli strains to UV radiation in orange juice (pH 3.5). The acid-shocked cells were obtained through culture in tryptic soy broth (TSB) with a final pH of 4.8, which was adjusted by hydrochloric, lactic, or citric acid and subsequently inoculated in orange juice at 4 °C for 30 days. No significant differences (p > 0.05) in survival in orange juice were observed between the serotypes O157:H7 and non-O157:H7 for acid-shocked experiments. After slow acidification, where the cells were cultured in TSB supplemented with glucose 1% (TSB + G), a significant increase (p < 0.05) in survival was observed for all strains evaluated. The D-values (radiation dose (J/cm2) necessary to decrease the microbial population by 90%) were determined as the inverse of the slopes of the regressions (k) obtained by plotting log (N/N0). The results show that among the strains tested, E. coli O157:H7 (303/00) and O26:H11 were the most resistant and sensitive strains, respectively. According to our results, the method of acid adaptation contributes to increasing the UV resistance for most of the strains tested.

Asunto(s)

RESUMEN

The use of photothermal processes has been proven effective in the control of microbial infections. Simultaneously, the localized surface plasmon resonance phenomena in metallic nanoparticles have been explored as an alternative strategy to achieve highly efficient localized heating. In this work, we propose the use of selected nanoheaters to improve the efficiency of fungal photothermal inactivation of Candida albicans through size optimization of plasmonic gold nanorods. Here, the optical heating of polyethylene glycol coated gold nanorods of varying sizes is evaluated, both theoretically and experimentally. A size-dependent computational approach was applied to identify metallic nanorods with maximized thermal performance at 800 nm, followed by the experimental comparison of optimal and suboptimal nanoheaters. Comparison among samples show temperatures of up to 53.0 °C for 41×10 nm gold nanorods against 32.3 °C for 90×25 nm, a percentage increase of ∼63% in photothermal inactivation assessments. Our findings reveal that gold nanorods of 41×10 nm exhibit superior efficiency in near-infrared (800 nm) photothermal inactivation of fungi, owing to their higher light-thermal conversion efficiency. The identification of high performance metallic nanoheaters may lead to the reduction of the nanoparticle dose used in plasmonic-based procedures and decrease the laser exposure time needed to induce cell death. Moreover, our results provide insights to better exploit plasmonic nanoparticles on photothermal inactivation protocols.

Asunto(s)

RESUMEN

BACKGROUND: Pharyngotonsillitis (PT) is an inflammatory and infectious condition affecting the tonsils in the oropharynx, predominantly caused by a variety of viral, fungal, and bacterial pathogens, including Streptococcus pyogenes. With the increasing challenge of antibiotic resistance, alternative therapeutic approaches are needed. METHODS: This study explores the effectiveness and safety of Photodynamic Therapy (PDT) as a therapeutic approach for managing acute PT. PDT involves the use of a photosensitizer, light, and molecular oxygen. We utilized a curcumin-based photosensitizer incorporated into a gum formulation, followed by exposure to blue LED irradiation (455 ± 30 nm, intensity of 200 mW for 6 min) with 1 to 2 PDT sessions depending on the clinical case. RESULTS: The treatment's impact was assessed through systematic monitoring of clinical progression post-treatment, encompassing clinical history, examination, and follow-up. In all three cases examined, PDT was observed to effectively eradicate the infection and prevent its recurrence during the period evaluated. CONCLUSION: Photodynamic Therapy, using a curcumin-based photosensitizer and blue LED light, appears to be a promising alternative to traditional antibiotics for the treatment of PT, demonstrating both efficacy in infection eradication and safety in application. Further studies are recommended to substantiate these findings and explore long-term outcomes.

Asunto(s)

RESUMEN

Candida albicans biofilm can cause diseases that are resistant to conventional antifungal agents. Photodynamic (PDI), sonodynamic (SDI), and sonophotodynamic (SPDI) inactivation have arisen as promising antimicrobial strategies. This study evaluated these treatments mediated by curcumin against C. albicans biofilms. For this, C. albicans biofilms were submitted to PDI, SDI, or SPDI with different light and ultrasound doses, then, the viability assay was performed to measure the effectiveness. Finally, a mathematical model was suggested to fit acquired experimental data and understand the synergistic effect of light and ultrasound in different conditions. The results showed that SPDI, PDI, and SDI reduced the viability in 6 ± 1; 1 ± 1; and 2 ± 1 log, respectively, using light at 60 J/cm2, ultrasound at 3 W/cm2, and 80 µM of curcumin. The viability reduction was proportional to the ultrasound and light doses delivered. These results encourage the use of SPDI for the control of microbial biofilm.

Asunto(s)

RESUMEN

Pseudomonas aeruginosa, a gram-negative bacterium, accounts for 7% of all hospital-acquired infections. Despite advances in medicine and antibiotic therapy, P. aeruginosa infection still results in high mortality rates of up to 62% in certain patient groups. This bacteria is also known to form biofilms, that are 10 to 1000 times more resistant to antibiotics compared to their free-floating counterparts. Photodynamic Inactivation (PDI) has been proved to be an effective antimicrobial technique for microbial control. This method involves the incubation of the pathogen with a photosensitizer (PS), then, a light at appropriated wavelength is applied, leading to the production of reactive oxygen species that are toxic to the microbial cells. Studies have focused on strategies to enhance the PDI efficacy, such as a pre-treatment with enzymes to degrade the biofilm matrix and/or an addition of inorganic salts to the PS. The aim of the present study is to evaluate the effectiveness of PDI against P. aeruginosa biofilm in association with the application of the enzymes prior to PDI (enzymatic pre-treatment) or the addition of potassium iodide (KI) to the photosensitizer solution, to increase the inactivation effectiveness of the treatment. First, a range of enzymes and PSs were tested, and the best protocols for combined treatments were selected. The results showed that the use of enzymes as a pre-treatment was effective to reduce the total biomass, however, when associated with PDI, mild bacterial reductions were obtained. Then, the use of KI in association with the PS was evaluated and the results showed that, PDI mediated by methylene blue (MB) in the presence of KI was able to completely eradicate the biofilm. However, when the PDI was performed with curcumin and KI, no additive reduction was observed. In conclusion, out of all strategies evaluated in the present study, the most promising strategy to improve PDI against P. aeruginosa biofilm was the use of KI in association with MB, resulting in eradication with 108 log bacterial inactivation.

Asunto(s)

RESUMEN

The presence of skin bacteria capable of forming biofilm, exhibiting antibiotic resistance, and displaying virulence represents a significant challenge in the field of transfusion medicine. This underscores the necessity of enhancing the microbiological safety of blood and blood components against pathogens with virulent characteristics. The aim of this work was to demonstrate bacterial inactivation in plasma by using a photoinactivation method against virulent bacteria and to evaluate coagulation factors before and after treatment. Logarithmic loads of biofilm-producing, antibiotic-resistant, and virulent bacteria isolated from skin (Enterobacter cloacae, Klebsiella ozaenae, and Staphylococcus epidermidis) were used in artificial contamination assays of fresh frozen plasma bags and subjected to photoreduction. FVIII and FI activity were evaluated before and after photoinactivation. The photoinactivation of plasma was demonstrated to be an effective method for the elimination of these bacteria. However, the efficiency of this method was found to be dependent on the bacterial load and the type of test microorganism. Conversely, decay of coagulation factors was observed with net residual activities of 61 and 69% for FVIII and FI, respectively. The photoinactivation system could have a bias in its effectiveness that is dependent on the test pathogen. These findings highlight the importance of employing technologies that increase the safety of the recipient of blood and/or blood components, especially against virulent bacteria, and show the relevance of the role of photoinactivation systems as an option in transfusion practice.

RESUMEN

Despite the wide variety of native and exotic fruits in Brazil, there is limited understanding of their ability to support pathogens during storage. This study aimed to evaluate the behavior of Salmonella enterica and Listeria monocytogenes inoculated into the pulp of eight fruits native and exotic to Brazil: Jenipapo (Genipa americana L.), Umbu (Spondias tuberosa Arruda), Maná (Solanum sessiliflorum), Cajá-manga (Spondias dulcis), Physalis (Physalis angulata L.), Feijoa (Acca sellowiana), Cupuaçu (Theobroma grandiflorum) (average pH < 3.3) and in a low acidy fruit: Abiu (Pouteria caimito) (pH 6.11). The pathogens were inoculated into the different fruits and stored at 10, 20, 30 and 37 °C for up to 12 h and 6 days, respectively. Among the fruits evaluated, Abiu was the only one that allowed Salmonella growth, showing higher δ-values at 20 and 30 °C (5.6 log CFU/g for both temperatures). For Physalis and Feijoa, there was a small reduction in the pathogen concentration (<1 log-cycle), mainly at 10 and 20 °C, indicating its ability to remain in the matrices. For the other fruits, notable negative δ-values were obtained, indicating a tendency towards microbial inactivation. The survival potential was significantly affected by temperature in Abiu, Maná, Cupuaçu, and Cajá-manga (p < 0.05). The same phenomena regarding δ-value were observed for L. monocytogenes population, with the greatest survival potential observed at 20 °C in Abiu (3.3 log CFU/g). Regarding the exponential growth rates in Abiu, the highest values were observed at 30 and 37 °C, both for Salmonella (4.6 and 4.9 log (CFU/g)/day, respectively) and for L. monocytogenes (2.8 and 2.7 log (CFU/g)/day, respectively), with no significant difference between both temperatures. Regarding microbial inactivation, L. monocytogenes showed greater resistance than Salmonella in practically all matrices. Jenipapo and Umbu were the pulps that, in general, had the greatest effect on reducing the population of pathogens. Furthermore, the increase in storage temperature seems to favor the increase on inactivation rates. In conclusion, Salmonella and L. monocytogenes can grow only in Abiu pulp, although they can survive in some acidic tropical fruits kept at refrigeration and abusive temperatures.

Asunto(s)

RESUMEN

Monascus ruber is an important fungus that causes spoilage in table olives, resulting in the darkening of the brine, the softening of the fruit, increased pH, and apparent mycelial growth. This study aimed to evaluate this resistance, providing a model to determine the optimal processing conditions for mitigating fungal contamination and prolonging shelf life without antifungal agents while optimizing pasteurization to reduce energy consumption. The resistance in brine (3.5% NaCl; pH 3.5) from Arauco cultivar green olives imported from Argentina was assessed. Four predictive models (log linear, log linear + shoulder, log linear + tail, log linear + shoulder + tail) estimated kinetic parameters for each survival curve. Log linear + shoulder + tail provided the best fit for 70 °C and 75 °C, with low RMSE (0.171 and 0.112) and high R2 values (0.98 and 0.99), respectively, while the log linear model was used for 80 °C. Decimal reduction times at 70, 75, and 80 °C were 24.8, 5.4, and 1.6 min, respectively, with a z-value of 8.2 °C. The current regulatory processes are insufficient to eliminate M. ruber at requisite levels, considering reduced antifungal agents.

RESUMEN

Cronobacter sakazakii is a potentially pathogenic bacterium that is resistant to osmotic stress and low aw, and capable of persisting in a desiccated state in powdered infant milks. It is widespread in the environment and present in various products. Despite the low incidence of cases, its high mortality rates of 40 to 80 % amongst neonates make it a microorganism of public health interest. This current study performed a comparative assessment between current reduction methods applied for C. sakazakii in various food matrices, indicating tendencies and relevant parameters for process optimization. A systematic review and meta-analysis were conducted, qualitatively identifying the main methods of inactivation and control, and quantitatively evaluating the effect of treatment factors on the reduction response. Hierarchical clustering dendrograms led to conclusions on the efficiency of each treatment. Review of recent research trend identified a focus on the potential use of alternative treatments, with most studies related to non-thermal methods and dairy products. Using random-effects meta-analysis, a summary effect-size of 4-log was estimated; however, thermal methods and treatments on dairy matrices displayed wider dispersions - of τ2 = 8.1, compared with τ2 = 4.5 for vegetal matrices and τ2 = 4.0 for biofilms. Meta-analytical models indicated that factors such as chemical concentration, energy applied, and treatment time had a more significant impact on reduction than the increase in temperature. Non-thermal treatments, synergically associated with heat, and treatments on dairy matrices were found to be the most efficient.

Asunto(s)

RESUMEN

This study investigated the antimicrobial effects of lactic acid (LA) (3%) and peracetic acid (PA) (300 ppm) on tilapia fillets (Oreochromis niloticus) by fogging (15 min) or by immersion (2 s) in a pool of Escherichia coli (NEWP 0022, ATCC 25922, and a field-isolated strain), Staphylococcus aureus (ATCC 25923 and a field-isolated strain), and Salmonella Typhimurium (ATCC 13311 and ATCC 14028), as well as the effects on the physicochemical characteristics of the fillets. Fogging was effective and the best application method to control S. Typhimurium regardless of the acid used, promoting reductions of 1.66 and 1.23 log CFU/g with PA and LA, respectively. Regarding E. coli, there were significant reductions higher than 1 log CFU/g, regardless of the treatment or acid used. For S. aureus, only immersion in PA showed no significant difference (p < 0.05). For other treatments, significant reductions of 0.98, 1.51, and 1.17 log CFU/g were observed for nebulized PA, immersion, and LA fogging, respectively. Concerning the pH of the samples, neither of the acids used differed from the control. However, treatments with LA, and fogging with PA, reduced the pH compared to immersion in PA. As for color parameters, L* and a* values showed changes regardless of the acid or method used, resulting in an improved perception of fillet quality. These results indicate that fogging and immersion are alternatives for reducing S. Typhimurium, E. coli, and S. aureus in tilapia fillets.

RESUMEN

L-type calcium channels are essential for the excitation-contraction coupling in cardiac muscle. The CaV1.2 channel is the most predominant isoform in the ventricle which consists of a multi-subunit membrane complex that includes the CaV1.2 pore-forming subunit and auxiliary subunits like CaVα2δ and CaVß2b. The CaV1.2 channel's C-terminus undergoes proteolytic cleavage, and the distal C-terminal domain (DCtermD) associates with the channel core through two domains known as proximal and distal C-terminal regulatory domain (PCRD and DCRD, respectively). The interaction between the DCtermD and the remaining C-terminus reduces the channel activity and modifies voltage- and calcium-dependent inactivation mechanisms, leading to an autoinhibitory effect. In this study, we investigate how the interaction between DCRD and PCRD affects the inactivation processes and CaV1.2 activity. We expressed a 14-amino acid peptide miming the DCRD-PCRD interaction sequence in both heterologous systems and cardiomyocytes. Our results show that overexpression of this small peptide can displace the DCtermD and replicate the effects of the entire DCtermD on voltage-dependent inactivation and channel inhibition. However, the effect on calcium-dependent inactivation requires the full DCtermD and is prevented by overexpression of calmodulin. In conclusion, our results suggest that the interaction between DCRD and PCRD is sufficient to bring about the current inhibition and alter the voltage-dependent inactivation, possibly in an allosteric manner. Additionally, our data suggest that the DCtermD competitively modifies the calcium-dependent mechanism. The identified peptide sequence provides a valuable tool for further dissecting the molecular mechanisms that regulate L-type calcium channels' basal activity in cardiomyocytes.

Asunto(s)

RESUMEN

The effect of photodynamic inactivation (PDI) sensitized by 5,10,15,20-tetra(4-N,N,N-trimethylammoniophenyl)porphyrin (TMAP4+) on different components of mono- and dual-species biofilms of Staphylococcus aureus and Escherichia coli was determined by different methods. First, the plate count technique showed that TMAP4+-PDI was more effective on S. aureus than E. coli biofilm. However, crystal violet staining revealed no significant differences between before and after PDI biofilms of both bacteria. On the other hand, the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method indicated a reduction in viable cells as the light exposure time increases in both, mono- and dual-species biofilms. Furthermore, it was determined that as the irradiation time increases, the amount of extracellular polymeric substances present in the biofilms decreased. This effect was presented in both strains and in the mixed biofilm, being more evident in S. aureus mono-specie biofilm. Finally, scanning electron microscopy analysis showed a decrease in the number of cells forming the biofilm after photosensitization treatments. This information makes it possible to determine whether the photodynamic action is based on damage to metabolic activity, extracellular matrix and/or biomass, which may be useful in establishing a fully effective PDI protocol for the treatment of microorganisms growing as biofilms.

Asunto(s)

RESUMEN

Mucormycosis is an extremely aggressive fungal disease with a high mortality rate, especially in people with compromised immune systems. Most cases of mucormycosis are caused by the fungus Rhizopus oryzae. The treatments used are based on high doses of antifungals, associated with surgical resections, when it is possible. However, even with this aggressive treatment, the estimated attributable mortality rate is high. There is therefore a need to develop adjuvant treatments. Photodynamic Inactivation (PDI) may be an auxiliary therapeutic option for mucormycosis. Due to the lack of reports in the literature on the morphology and photodynamic inactivation of R. oryzae, characterization of the fungus using Confocal Microscopy and Transmission Electron Microscopy, and different protocols using Photodithazine® (PDZ), a chlorin e6 compound, as a photosensitizer, were performed. The fungus growth rate under different concentrations and incubation times of the photosensitizer and its association with the surfactant Sodium Dodecyl Sulphate (SDS) was evaluated. For the hyphae, both in the light and dark phases, in the protocols using only PDZ, no effective photodynamic response was observed. Meanwhile with the combination of SDS 0.05% and PDZ, inhibition growth rates of 98% and 72% were achieved for the white and black phase, respectively. In the conidia phase, only a 1.7 log10 reduction of the infective spores was observed. High concentration of melanin and the complex and resistant structures, especially at the black phase, results in a high limitation of the PDI inactivation response. The combined use of the SDS resulted in an improved response, when compared to the one obtained with the amphotericin B treatment.

Asunto(s)

RESUMEN

The worldwide market for vegetable and fruit juices stands as a thriving sector with projected revenues reaching to $81.4 billion by 2024 and an anticipated annual growth rate of 5.27% until 2028. Juices offer a convenient means of consuming bioactive compounds and essential nutrients crucial for human health. However, conventional thermal treatments employed in the juice and beverage industry to inactivate spoilage and pathogenic microorganisms, as well as endogenous enzymes, can lead to the degradation of bioactive compounds and vitamins. In response, non-thermal technologies have emerged as promising alternatives to traditional heat processing, with pulsed electric field (PEF) technology standing out as an innovative and sustainable choice. In this context, this comprehensive review investigated the impact of PEF on the microbiological, physicochemical, functional, nutritional, and sensory qualities of vegetable and fruit juices. PEF induces electroporation phenomena in cell membranes, resulting in reversible or irreversible changes. Consequently, a detailed examination of the effects of PEF process variables on juice properties is essential. Monitoring factors such as electric field strength, frequency, pulse width, total treatment time, and specific energy is important to ensure the production of a safe and chemically/kinetically stable product. PEF technology proves effective in microbial and enzymatic inactivation within vegetable and fruit juices, mitigating factors contributing to deterioration while maintaining the physicochemical characteristics of these products. Furthermore, PEF treatment does not compromise the content of substances with functional, nutritional, and sensory properties, such as phenolic compounds and vitamins. When compared to alternative processing methods, such as mild thermal treatments and other non-thermal technologies, PEF treatment consistently demonstrates comparable outcomes in terms of physicochemical attributes, functional properties, nutritional quality, and overall safety.

Asunto(s)

RESUMEN

Introduction: Providing conventional, restorative dental care to children with special healthcare needs (CSHCN) often requires sedation using general anesthesia. Saliva consistency, diet, and oral hygiene practice are different for CSHCN, and limited evidence is available on the efficacy of silver fluoride (SF) for the management of carious lesions for this vulnerable population. Methods: Parents of CSHCN were educated about silver fluoride as a treatment option for caries. In total, 550 carious lesions from 100 participants were identified and scored according to the Nyvad Caries criteria. A total of 100 lesions with Nyvad scores 1, 2, and 3 were treated with a single application of silver fluoride and observed postoperatively at 1, 3, and 6 weeks. Result: The results indicate statistically significant (p < 0.05) differences in lesion remineralization over the 6-week follow-up period. At the 6-week follow-up, more than 85% of all lesions were remineralized across all children, regardless of condition or original Nyvad score of 1, 2, or 3. Conclusion: A single application of silver fluoride has demonstrated effectiveness in remineralization and inactivation of carious lesions over 6 weeks among Brazilian CSHCN. Silver fluoride should be considered an option for the management of carious lesions among CSHCN. Further studies are recommended, including larger sample sizes, longer follow-up times, a second application of SF, and different special needs conditions.

RESUMEN

Recent advancements in enzyme research have unveiled a new proteoform of bovine trypsin, expanding our understanding of this well-characterized enzyme. While generally similar to other trypsins, this novel proteoform comprises three polypeptide chains, marking a significant difference in activity, kinetic properties, and conformational stability. Compared with the already known bovine trypsin proteoforms, the results showed a lower: activity, kcat and kcat.KM-1 and protein 'foldedness' ratio for the new proteoform. Molecular autolysis, a common feature in trypsin and chymotrypsin, has been explored through comparative physical chemistry properties with other proteoforms. This new proteoform of trypsin not only enriches the existing enzyme repertoire but also promises to shed light on the intricate physiological pathway for enzyme inactivation. Our results suggest that the new trypsin proteoform is one of the likely final pathways for enzyme inactivation in a physiological environment. This discovery opens up new avenues for further research into the functional implications of this new trypsin proteoform.

Asunto(s)

RESUMEN

Quinolone resistance has been largely related to the presence of specific point mutations in chromosomal targets, with an accessory role of impaired uptake and enhanced pump-out. Meanwhile the relevance of transferable mechanisms of resistance able to protect the target of pump-out or inactivate quinolones has been increasingly reported since 1998. Nevertheless, bacteria have other strategies and mechanisms allowing them to survive and even proliferate in the presence of quinolones, which might be qualified as resistance or resilience mechanisms. These include decreasing levels of quinolone target production, transient amoeba protection, benthonic lifestyle, nutrient-independent slow growth, activation of stringent response, inactivation or degradation of quinolones as well as apparently unrelated or forgotten chromosomal mutations. These mechanisms have been largely overlooked, either because of the use of classical approaches to antibiotic resistance determination or due to the low increase in final minimum inhibitory concentration levels. This article is devoted to a review of a series of these mechanisms.

RESUMEN

A porphyrin-BODIPY dyad (P-BDP) was obtained through covalent bonding, featuring a two-segment design comprising a light-harvesting antenna system connected to an energy acceptor unit. The absorption spectrum of P-BDP resulted from an overlap of the individual spectra of its constituent parts, with the fluorescence emission of the BODIPY unit experiencing significant quenching (96 %) due to the presence of the porphyrin unit. Spectroscopic, computational, and redox investigations revealed a competition between photoinduced energy and electron transfer processes. The dyad demonstrated the capability to sensitize both singlet molecular oxygen and superoxide radical anions. Additionally, P-BDP effectively induced the photooxidation of L-tryptophan. In suspensions of Staphylococcus aureus cells, the dyad led to a reduction of over 3.5 log (99.99 %) in cell survival following 30 min of irradiation with green light. Photodynamic inactivation caused by P-BDP was also extended to the individual bacterium level, focusing on bacterial cells adhered to a surface. This dyad successfully achieved the total elimination of the bacteria upon 20 min of irradiation. Therefore, P-BDP presents an interesting photosensitizing structure that takes advantage of the light-harvesting antenna properties of the BODIPY unit combined with porphyrin, offering potential to enhance photoinactivation of bacteria.

Asunto(s)

RESUMEN

This is a protocol for an overview to summarize the findings of Systematic Reviews (SR) dealing with Photodynamic Inactivation (PDI) for control of oral diseases. Specific variables of oral infectious will be considered as outcomes, according to dental specialty. Cochrane Database of Systematic Reviews (CDSR), MEDLINE, LILACS, Embase, and Epistemonikos will be searched, as well as reference lists. A search strategy was developed for each database using only terms related to the intervention (PDI) aiming to maximize sensitivity. After checking for duplicate entries, selection of reviews will be performed in a two-stage technique: two authors will independently screening titles and abstracts, and then full texts will be assessed for inclusion/exclusion criteria. Any disagreement will be resolved through discussion and/or consultation with a third reviewer. Data will be extracted following the recommendations in Chapter V of Cochrane Handbook and using an electronic pre-specified form. The evaluation of the methodological quality and risk of bias (RoB) of the SR included will be carried out using the AMSTAR 2 and ROBIS. Narrative summaries of relevant results from the individual SR will be carried out and displayed in tables and figures. A specific summary will focus on PDI parameters and study designs, such as the type and concentration of photosensitizer, pre-irradiation time, irradiation dosimetry, and infection or microbiological models, to identify the PDI protocols with clinical potential. We will summarize the quantitative results of the SRs narratively.

Asunto(s)