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Synergistic in vitro effects of indocyanine green and ethylenediamine tetraacetate-mediated photodynamic antimicrobial chemotherapy combined with antibiotics for resistant bacterial biofilms in diabetic foot infection
摘要： Background: Antibiotic resistance has emerged as one of the most important determinants in diabetic foot infections outcomes. Photodynamic antimicrobial chemotherapy (PACT) has been proposed as an alternative approach for inactivating bacteria, especially resistant bacterial biofilms. This research investigated the synergistic effects of PACT mediated by the photosensitizer indocyanine green (ICG) and ethylenediamine tetraacetate (EDTA) combined with antibiotics against common pathogens of diabetic foot ulcer infection, including Staphylococcus aureus and Pseudomonas aeruginosa, in vitro. Methods: Planktonic bacteria and biofilms of S. aureus and P. aeruginosa were incubated with ICG and EDTA, and then exposed to laser treatment. Quantitative viable counting estimates the phototoxic effects on S. aureus and P. aeruginosa. The susceptibility of methicillin-resistant S. aureus (MRSA) and multidrug-resistant P. aeruginosa (MRPA) to PACT treatment was detected by disk diffusion and micro-broth dilution methods. Confocal microscopy was used to detect the morphology of biofilms treated with PACT and antibiotics. The resazurin assay was used to quantify the metabolic activity of bacteria in biofilms. Results: PACT mediated by ICG and EDTA led to a more pronounced antibacterial effect in S. aureus and P. aeruginosa compared with ICG alone-mediated PACT. P. aeruginosa was more sensitive to ICG and EDTA-mediated PACT than S. aureus. After PACT treatment, the susceptibility of MRSA and MRPA to antibiotics increased. Furthermore, PACT combined with antibiotic treatment significantly contributed to killing bacteria in the biofilm and disrupting biofilm structure. Conclusions: ICG and EDTA-mediated PACT combined with antibiotics synergistically enhanced the effects of sterilization and biofilm destruction.
关键词： photodynamic antimicrobial chemotherapy,antibacterial effect,diabetic foot infection,bacterial biofilm,EDTA,indocyanine green
更新于2025-09-23 15:23:52
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ROS mediated antibacterial activity of photoilluminated riboflavin: A photodynamic mechanism against nosocomial infections
摘要： Nosocomial infections are a major threat to modern therapeutics. The major causative agent of these infections is multidrug-resistant gram-negative bacteria, which impart high morbidity and mortality rate. This has led to an urge for the development of new antibiotics. Antimicrobial photodynamic therapy is a promising strategy to which till date no resistant strain has been reported. Since the efficacy of photodynamic therapy largely depends on the selection and administration of an appropriate photosensitizer, therefore, the realization of clinically active photosensitizers is an immediate need. Here, by using E. coli as a study model we have demonstrated the antimicrobial photodynamic potential of riboflavin. Intracellular ROS formation by DCFH-DA assay, lipid peroxidation, protein carbonylation, LDH activity was measured in treated bacterial samples. Enzymatic (SOD, CAT, GSH) antioxidants and non-enzymatic (GSH) was further evaluated. Bacterial death was confirmed by colony forming assay, optical microscopy and scanning electron microscopy. The treated bacterial cells exhibited abundant ROS generation and marked increment in the level of oxidative stress markers as well as significant reduction in LDH activity. Marked reduction in colony forming units was also observed. Optical microscopic and SEM images further confirmed the bacterial death. Thus, we can say that photoilluminated riboflavin renders the redox status of bacterial cells into a compromised state leading to significant membrane damage ultimately causing bacterial death. This study aims to add one more therapeutic dimension to photoilluminated riboflavin as it can be effectively employed in targeting bacterial biofilms occurring on hospital wares causing several serious medical conditions.
关键词： ROS,Antibacterial,Riboflavin,Photodynamic therapy,Nosocomial infection
更新于2025-09-23 15:23:52
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Noninvasive biodegradable nanoparticles-in-nanofibers single-dose ocular insert: <i>in vitro</i> , <i>ex vivo</i> and <i>in vivo</i> evaluation
摘要： Aim: This study involves, for the first time, the development of mucoadhesive biodegradable polymeric-multilayered nanoparticles-in-nanofibers (NPs-in-NFs) matrix as an innovative single-dose noninvasive ocular-insert that could substitute conventional ocular dosage-forms. Materials & methods: Azithromycin-loaded poly(lactic-co-glycolic acid) copolymer/pluronic NPs were developed then incorporated into electrospun polyvinylpyrrolidone NFs, and tested for their efficient treatment of ocular bacterial infection. Results: Release and permeation studies proved the ability of the insert to control drug release over 10 days. Conclusion: The incorporation of NPs into NFs achieved several other benefits like increasing ocular residence and contact time with conjunctival tissue, accurate dose delivery, sustaining drug release with constant rate, reducing frequency of administration, improving bioavailability along with decreasing incidence of visual and systemic side effects.
关键词： nanofibers,electrospun,bacterial infection,single-dose,ocular,azithromycin
更新于2025-09-23 15:23:52
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Porous Organic Polymer-Coated Band-Aids for Phototherapy of Bacteria-Induced Wound Infection
摘要： Band-Aids have been widely used for wound care. For most adhesive bandages, however, they have limited capacity to speed up the wound healing process, which in turn may cause serious wound infections. In this study, antibacterial Band-Aids, combining porphyrin based porous organic polymers (POPs) with commercial antibiotics-free Band-Aids, are designed. Under white light irradiation, POP can produce effective photothermal heat, as well as highly reactive oxygen species (ROS), thereby triggering the potent hyperthermia and simultaneous ROS increase on wounds. What's more, white-light is similar with sunlight, which makes POP-based Band-Aids (PBA) ideal wound dressings for wound disinfection.
关键词： wound infection,porous organic polymers,band-aids,white light
更新于2025-09-23 15:23:52
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Identification of Wheat Yellow Rust Using Optimal Three-Band Spectral Indices in Different Growth Stages
摘要： Yellow rust, a widely known destructive wheat disease, affects wheat quality and causes large economic losses in wheat production. Hyperspectral remote sensing has shown potential for the detection of plant disease. This study aimed to analyze the spectral reflectance of the wheat canopy in the range of 350–1000 nm and to develop optimal spectral indices to detect yellow rust disease in wheat at different growth stages. The sensitive wavebands of healthy and infected wheat were located in the range 460–720 nm in the early-mid growth stage (from booting to anthesis), and in the ranges 568–709 nm and 725–1000 nm in the mid-late growth stage (from filling to milky ripeness), respectively. All possible three-band combinations over these sensitive wavebands were calculated as the forms of PRI (Photochemical Reflectance Index) and ARI (Anthocyanin Reflectance Index) at different growth stages and assessed to determine whether they could be used for estimating the severity of yellow rust disease. The optimal spectral index for estimating wheat infected by yellow rust disease was PRI (570, 525, 705) during the early-mid growth stage with R2 of 0.669, and ARI (860, 790, 750) during the mid-late growth stage with R2 of 0.888. Comparison of the proposed spectral indices with previously reported vegetation indices were able to satisfactorily discriminate wheat yellow rust. The classification accuracy for PRI (570, 525, 705) was 80.6% and the kappa coefficient was 0.61 in early-mid growth stage, and the classification accuracy for ARI (860, 790, 750) was 91.9% and the kappa coefficient was 0.75 in mid-late growth stage. The classification accuracy of the two indices reached 84.1% and 93.2% in the early-mid and mid-late growth stages in the validated dataset, respectively. We conclude that the three-band spectral indices PRI (570, 525, 705) and ARI (860, 790, 750) are optimal for monitoring yellow rust infection in these two growth stages, respectively. Our method is expected to provide a technical basis for wheat disease detection and prevention in the early-mid growth stage, and the estimation of yield losses in the mid-late growth stage.
关键词： yellow rust disease,three-band spectral index,different growth stages,hyperspectral remote sensing,wheat infection
更新于2025-09-23 15:22:29
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Dual-Modal In Vivo Fluorescence/Photoacoustic Microscopy Imaging of Inflammation Induced by GFP-Expressing Bacteria
摘要： In this study, dual-modal fluorescence and photoacoustic microscopy was performed for noninvasive and functional in vivo imaging of inflammation induced by green fluorescent protein (GFP) transfected bacteria in mice ear. Our imaging results demonstrated that the multimodal imaging technique is able to monitor the tissue immunovascular responses to infections with molecular specificity. Our study also indicated that the combination of photoacoustic and fluorescence microscopy imaging can simultaneously track the biochemical changes including the bacterial distribution and morphological change of blood vessels in the biological tissues with high resolution and enhanced sensitivity. Consequently, the developed method paves a new avenue for improving the understanding of the pathology mechanism of inflammation.
关键词： GFP-expressing bacteria,fluorescence imaging,biosensor,photoacoustic microscopy,inflammation/infection
更新于2025-09-23 15:22:29
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The surgical wound in infrared: thermographic profiles and early stage test-accuracy to predict surgical site infection in obese women during the first 30?days after caesarean section
摘要： Background: Prophylactic antibiotics are commonly prescribed intra-operatively after caesarean section birth, often at high doses. Even so, wound infections are not uncommon and obesity increases the risk. Currently, no independent wound assessment technology is available to stratify women to low or high risk of surgical site infection (SSI). Study Aim: to investigate the potential of non-invasive infrared thermography (IRT), performed at short times after surgery, to predict later SSI. Methods: IRT was undertaken in hospital on day 2 with community follow up (days 7, 15, 30) after surgery. Thermal maps of wound site and abdomen were accompanied by digital photographs, the latter used for wound assessment by six experienced healthcare professionals. Confirmatory diagnosis of SSI was made on the basis of antibiotic prescribing by the woman’s community physician with logistic regression models derived to model dichotomous outcomes. Results: Fifty-three women aged 21–44 years with BMI 30.1–43.9 Kg.m? 2 were recruited. SSI rate (within 30 days) was 28%. Inter-rater variability for ‘professional’ opinion of wound appearance showed poor levels of agreement. Two regions of interest were interrogated; wound site and abdomen. Wound site temperature was consistently elevated (1.5 °C) above abdominal temperature with similar values at days 2,7,15 in those who did and did not, develop SSI. Mean abdominal temperature was lower in women who subsequently developed SSI; significantly so at day 7. A unit (1 °C) reduction in abdominal temperature was associated with a 3-fold raised odds of infection. The difference between the sites (wound minus abdomen temperature) was significantly associated with odds of infection; with a 1 °C widening in temperature associated with an odds ratio for SSI of 2.25 (day 2) and 2.5 (day 7). Correct predictions for wound outcome using logistic regression models ranged from 70 to 79%; Conclusions: IRT imaging of wound and abdomen in obese women undergoing c-section improves upon visual (subjective) wound assessment. The proportion of cases correctly classified using the wound-abdominal temperature differences holds promise for precision and performance of IRT as an independent SSI prognostic tool and future technology to aid decision making in antibiotic prescribing.
关键词： Antibiotics,Caesarean section,Obesity,Surgical site infection,Infrared thermography,Prognosis,Thermal mapping
更新于2025-09-23 15:22:29
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Evaluation of photodynamic therapy effect along with colistin on pandrug-resistant <i>Acinetobacter baumannii</i>
摘要： Background and Aims: Pandrug-resistant Acinetobacter baumannii (PDRAB) are including colistin resistant starins (CoRAB) which cause infections potentially untreatable infections. Recently, incidence of these strains are increasing worldwide. Therefore, new approaches, methods and strategies are urgently needed for treatment and eradication of infections due to PDRAB. So the aim of this study was to evaluate the efficacy of photodynamic therapy (PDT) in combination treatment with colistin against PDRAB. Materials and Methods: PDRAB which was isolated from burn patients was used as a test strain. PDT carried out in which toluidine blue O (TBO) and light-emitting diode (LED) were used as photosensitizer and radiation source, respectively. Then, the effect of PDT plus colistin was evaluated on CoRAB and the colony-forming units of each tested groups calculated. Finally, confirmation of antibacterial activity of combination therapy was carried out using scanning electron microscope. Results: PDT declined bacterial count in comparing with control group by 83.7% of killing percentage, in other words, less than one log reduction. While PDT in combination with colistin showed high synergetic effect against A. baumannii in all concentrations of colistin tested by 100% of killing percentage with 9-log reduction. Conclusions: According to our results, PDT alone couldn’t eliminate all of the treated bacterial cells. But when combined with colistin, it killed all of the treated bacterial cells in all tested concentrations. Also PDT decreased the minimal inhibitory concentration of colistin against PDRAB by more than 11 fold.
关键词： colistin,Acinetobacter baumannii,wound infection,toluidine blue O,photodynamic therapy,pandrug resistance
更新于2025-09-23 15:21:21
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Disinfection of Contaminated Metal Implants with an Er:YAG Laser
摘要： Infections related to orthopedic procedures are considered particularly severe when implantation materials are used, because effective treatments for biofilm removal are lacking. In this study, the relatively new approach for infection control by using an erbium:yttrium‐aluminum‐garnet (Er:YAG) laser was tested. This laser vaporizes all water containing cells in a very effective, precise, and predictable manner and results in only minimal thermal damage. For preliminary testing, 42 steel plates and 42 pins were seeded with mixed cultures. First, the minimally necessary laser energy for biofilm removal was determined. Subsequently, the effectiveness of biofilm removal with the Er:YAG laser and the cleansing of the metal implants with octenidine‐soaked gauze was compared. Then, we compared the effectiveness of biofilm removal on 207 steel pins from 41 patients directly after explantation. Sonication and scanning electron microscopy were used for analysis. Laser fluences exceeding 2.8 J/cm2 caused a complete extinction of all living cells by a single‐laser impulse. Cleansing with octenidine‐soaked gauze and irradiation with the Er:YAG laser are both thoroughly effective when applied to seeded pins. In contrast, when explanted pins with fully developed biofilms were analyzed, we found a significant advantage of the laser procedure. The Er:YAG laser offers a secure, complete, and nontoxic eradication of all kinds of pathogens from metal implants without damaging the implant and without the possible development of resistance. The precise noncontact removal of adjacent tissue is a decisive advantage over conventional disinfectants. Therefore, laser irradiation could become a valuable method in every debridement, antibiotics, and implant retention procedure.
关键词： implant‐related infection,DAIR,Er:YAG laser,laser disinfection,pin‐tract infection,biofilm removal
更新于2025-09-23 15:21:01
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Selective Uropathogenic E. coli Detection Using Crossed Surface-Relief Gratings
摘要： Urinary tract infections (UTIs) are one of the major burdens on public healthcare worldwide. One of the primary causes of UTIs is the invasion of the urinary tract by uropathogenic Escherichia coli (UPEC). Improper treatment of bacterial infections like UTIs with broad-spectrum antibiotics has contributed to the rise of antimicrobial resistance, necessitating the development of an inexpensive, rapid and accurate detection of UPEC. Here, we present real-time, selective and label-free detection of UPEC using crossed surface-relief gratings (CSRGs) as nanometallic sensors incorporated into an optical sensing platform. CSRGs enable real-time sensing due to their unique surface plasmon resonance (SPR)-based light energy exchange, resulting in detection of a very-narrow-bandwidth SPR signal after the elimination of residual incident light. The platform’s sensing ability is experimentally demonstrated by the detection of bulk refractive index (RI) changes, with a bulk sensitivity of 382.2 nm/RIU and a resolution in the order of 10?6 RIU. We also demonstrate, for the ?rst time, CSRG-based real-time selective capture and detection of UPEC in phosphate-buffered saline (PBS) solution, in clinically relevant concentrations, as opposed to other UTI-causing Gram-negative bacteria. The platform’s detection limit is calculated to be 105 CFU/mL (concentration on par with the clinical threshold for UTI diagnosis), with a dynamic range spanning four orders of magnitude. This work paves the way for the development of inexpensive point-of-care diagnosis devices focusing on effective treatment of UTIs, which are a burden on public healthcare due to the rise in the number of cases and their recurrences in the recent past.
关键词： crossed surface-relief gratings,nanoplasmonics,surface plasmon resonance,urinary tract infection,biosensing,uropathogenic E. coli,surface-relief gratings
更新于2025-09-23 15:21:01