Presence and Causes of Sterilization Equipment Failures with Biological Indicators in Dental Offices in Mexico: A Longitudinal Cohort.

Background/Objectives: Sterilization in dental practice is crucial for infection prevention. The aim of this study was to identify the presence and causes of bacterial growth using biological indicators in dental sterilization equipment in San Luis Potosí, S.L.P., Mexico, with different consecutive measurements over a year. Methods: This longitudinal cohort, conducted from January 2022 to January 2024 in San Luis Potosí, Mexico, aimed to identify the presence and causes of bacterial growth in dental sterilization equipment using biological indicators. A total of 207 dental offices were approached, and 175 participated, providing data through questionnaires and monitoring sterilization cycles with BIs. The checks were bimonthly for one year, with a total of six checks. Results: (a) An 11% (n = 1188) incidence of bacterial growth was observed, with a higher percentage in dry heat equipment (13%). (b) Upon analyzing the six consecutive verifications over a year, no statistically significant differences were observed in the failures of the sterilization cycles when comparing the two pieces of equipment. (c) Error in temperature and time of the equipment (OR = 4.0, 95% CI = 1.6-3.9, p = 0.0001) was significantly associated with the presence of bacterial growth during the one-year period. Conclusions: Monitoring sterilization cycles and identifying the causes of bacterial growth with different consecutive verifications decreased the presence of bacterial growth (failures) during the one-year period.

Fluoroquinolone Analogs, SAR Analysis, and the Antimicrobial Evaluation of 7-Benzimidazol-1-yl-fluoroquinolone in In Vitro, In Silico, and In Vivo Models.

Structure-activity relationship (SAR) studies allow the evaluation of the relationship between structural chemical changes and biological activity. Fluoroquinolones have chemical characteristics that allow their structure to be modified and new analogs with different therapeutic properties to be generated. The objective of this research is to identify and select the C-7 heterocycle fluoroquinolone analog (FQH 1-5) with antibacterial activity similar to the reference fluoroquinolone through in vitro, in silico, and in vivo evaluations. First, SAR analysis was conducted on the FQH 1-5, using an in vitro antimicrobial sensibility model in order to select the best compound. Then, an in silico model mechanism of action analysis was carried out by molecular docking. The non-bacterial cell cytotoxicity was evaluated, and finally, the antimicrobial potential was determined by an in vivo model of topical infection in mice. The results showed antimicrobial differences between the FQH 1-5 and Gram-positive and Gram-negative bacteria, identifying the 7-benzimidazol-1-yl-fluoroquinolone (FQH-2) as the most active against S. aureus. Suggesting the same mechanism of action as the other fluoroquinolones; no cytotoxic effects on non-bacterial cells were found. FQH-2 was demonstrated to decrease the amount of bacteria in infected wound tissue.

Antimicrobial activity of the Flo peptide produced in Scenedesmus acutus and Nannochloropsis oculata.

The continuous increase of bacterial pathogen resistance to conventional antibiotics has challenged the research community to develop new antimicrobial strategies. Antimicrobial peptides (AMP) are a promising alternative to combat multidrug-resistant strains compared to conventional antibiotics because of their biocompatibility. In the present study, the Flo peptide, an AMP from the Moringa oleifera tree, was expressed in the chloroplast of the microalgae Nannochloropsis oculata and Scenedesmus acutus. The transgene insertion was verified by PCR amplification, and the homoplasmy was corroborated in spectinomycin-resistant lines. The identification and quantification of the peptide were performed using ELISA. The antimicrobial activity was studied against the Gram-negative Escherichia coli (ATCC 25,922) and Klebsiella pneumoniae (ATCC 700,603). The inflammatory response of the total soluble proteins of transplastomic N. oculata was assessed by measuring secretion of the cytokines IL-6, IL-10, and alpha-tumor necrosis (TNF-α), and cytotoxicity was assessed. These results provide a potential strategy to produce the Flo peptide in microalgae with antibacterial activities.

An Analysis COVID-19 in Mexico: a Prediction of Severity.

BACKGROUND: Coronavirus disease 2019 (COVID-19) causes a mild illness in most cases; forecasting COVID-19-associated mortality and the demand for hospital beds and ventilators are crucial for rationing countries' resources. OBJECTIVE: To evaluate factors associated with the severity of COVID-19 in Mexico and to develop and validate a score to predict severity in patients with COVID-19 infection in Mexico. DESIGN: Retrospective cohort. PARTICIPANTS: We included 1,435,316 patients with COVID-19 included before the first vaccine application in Mexico; 725,289 (50.5%) were men; patient's mean age (standard deviation (SD)) was 43.9 (16.9) years; 21.7% of patients were considered severe COVID-19 because they were hospitalized, died or both. MAIN MEASURES: We assessed demographic variables, smoking status, pregnancy, and comorbidities. Backward selection of variables was used to derive and validate a model to predict the severity of COVID-19. KEY RESULTS: We developed a logistic regression model with 14 main variables, splines, and interactions that may predict the probability of COVID-19 severity (area under the curve for the validation cohort = 82.4%). CONCLUSIONS: We developed a new model able to predict the severity of COVID-19 in Mexican patients. This model could be helpful in epidemiology and medical decisions.

Synthesis and Antimicrobial Evaluation of Amino Acid Naphthoquinone Derivatives as Potential Antibacterial Agents.

BACKGROUND: The synthesis and biological evaluation of 1,4-naphthoquinone derivatives are of great interest since these compounds exhibit strong antibacterial, antifungal, antimalarial, and anticancer activities. The electronic properties of naphthoquinones are usually modulated by attaching functional groups containing nitrogen, oxygen, and sulfur atoms, which tune their biological potency and selectivity. METHODS: A series of 13 amino acid 1,4-naphthoquinone derivatives was synthesized under assisted microwave and ultrasound conditions. The antibacterial activity of compounds was tested against American Type Culture Collection (ATCC): Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Enterococcus faecalis, as well as 2 multidrug resistant pathogens: E. coli and S. aureus from clinical isolated. Minimal inhibitory concentration (MIC) was determined using the broth microdilution method. RESULTS: MIC of derivatives 4-11, 14, and 16 showed antimicrobial activity against Gram-positive and Gram-negative bacteria. Antimicrobial activities of the compounds 4-8 and 14 were ≤MIC 24.7 µg mL-1 against all the reference strains; even more, compound 6 showed the most potent activity with an MIC of 3.9 µg mL-1 on S. aureus. On the clinical isolated, the compounds 7, 8, and 14 showed an MIC of 49.7 and 24.7 µg mL-1 against S. aureus and E. coli, respectively. About ADME properties and Osiris analysis, the compounds 4-16 presented high gastrointestinal absorption and good characteristics for oral bioavailability, and compound 14 was the less toxic. CONCLUSION: Amino acid 1,4-naphthoquinone derivatives showed good in vitro antibacterial activity against clinical strains, and modifications on C-3 with a chloride atom enhanced the efficiency against the same pathogens.

Development of Radiosterilized Porcine Skin Electrosprayed with Silver Nanoparticles Prevents Infections in Deep Burns.

Extensive burns represent a significant challenge in biomedicine due to the multiple systemic and localized complications resulting from the major skin barrier loss. The functionalization of xenografts with nanostructured antibacterial agents proposes a fast and accessible application to restore barrier function and prevent localized bacterial contamination. Based on this, the objective of this work was to functionalize a xenograft by electrospray deposition with silver nanoparticles (AgNPs) and to evaluate its antibiofilm and cytotoxic effects on human fibroblasts. Initially, AgNPs were synthesized by a green microwave route with sizes of 2.1, 6.8, and 12.2 nm and concentrations of 0.055, 0.167, and 0.500 M, respectively. The AgNPs showed a size relationship directly proportional to the concentration of AgNO3, with a spherical and homogeneous distribution determined by high-resolution transmission electron microscopy. The surface functionalization of radiosterilized porcine skin (RPS) via electrospray deposition with the three AgNP concentrations (0.055, 0.167, and 0.500 M) in the epidermis and the dermis showed a uniform distribution on both surfaces by energy-dispersive X-ray spectroscopy. The antibiofilm assays of clinical multidrug-resistant Pseudomonas aeruginosa showed significant effects at the concentrations of 0.167 and 0.500 M, with a log reduction of 1.3 and 2.6, respectively. Additionally, viability experiments with human dermal fibroblasts (HDF) exposed to AgNPs released from functionalized porcine skin showed favorable tolerance, with retention of viability more significant than 90% for concentrations of 0.05 and 0.167 M after 24 h exposure. Antibacterial activity combined with excellent biocompatibility makes this biomaterial a candidate for antibacterial protection by inhibiting bacterial biofilms in deep burns during early stages of development.

Silver-pig skin nanocomposites and mesenchymal stem cells: suitable antibiofilm cellular dressings for wound healing.

BACKGROUND: Treatment of severe or chronic skin wounds is an important challenge facing medicine and a significant health care burden. Proper wound healing is often affected by bacterial infection; where biofilm formation is one of the main risks and particularly problematic because it confers protection to microorganisms against antibiotics. One avenue to prevent bacterial colonization of wounds is the use of silver nanoparticles (AgNPs); which have proved to be effective against non-multidrug-resistant and multidrug-resistant bacteria. In addition, the use of mesenchymal stem cells (MSC) is an excellent option to improve wound healing due to their capability for differentiation and release of relevant growth factors. Finally, radiosterilized pig skin (RPS) is a biomatrix successfully used as wound dressing to avoid massive water loss, which represents an excellent carrier to deliver MSC into wound beds. Together, AgNPs, RPS and MSC represent a potential dressing to control massive water loss, prevent bacterial infection and enhance skin regeneration; three essential processes for appropriate wound healing with minimum scaring. RESULTS: We synthesized stable 10 nm-diameter spherical AgNPs that showed 21- and 16-fold increase in bacteria growth inhibition (in comparison to antibiotics) against clinical strains Staphylococcus aureus and Stenotrophomonas maltophilia, respectively. RPS samples were impregnated with different AgNPs suspensions to develop RPS-AgNPs nanocomposites with different AgNPs concentrations. Nanocomposites showed inhibition zones, in Kirby-Bauer assay, against both clinical bacteria tested. Nanocomposites also displayed antibiofilm properties against S. aureus and S. maltophilia from RPS samples impregnated with 250 and 1000 ppm AgNPs suspensions, respectively. MSC were isolated from adipose tissue and seeded on nanocomposites; cells survived on nanocomposites impregnated with up to 250 ppm AgNPs suspensions, showing 35% reduction in cell viability, in comparison to cells on RPS. Cells on nanocomposites proliferated with culture days, although the number of MSC on nanocomposites at 24 h of culture was lower than that on RPS. CONCLUSIONS: AgNPs with better bactericide activity than antibiotics were synthesized. RPS-AgNPs nanocomposites impregnated with 125 and 250 ppm AgNPs suspensions decreased bacterial growth, decreased biofilm formation and were permissive for survival and proliferation of MSC; constituting promising multi-functional dressings for successful treatment of skin wounds.

Antinociceptive Activity of Ent-Dihydrotucumanoic Acid Isolated from Gymnosperma glutinosum Spreng Less.

Preclinical Research The diterpene ent-dihydrotumanoic acid (DTA) was among the compounds isolated from Gymnosperma glutinosum (Spreng) Less (Asteraceae). There are no reports regarding the pharmacological effects of DTA. Cytotoxicity against cancer cells (1-250 µM), and the antibacterial (50-1400 µM) activity of DTA were evaluated using the MTT assay, and the minimum inhibitory concentration test, respectively. The antidiarrheal (1-100 mg/kg p.o.) and anti-inflammatory (2 mg/ear) effects of DTA were evaluated using castor oil and 12-O-tetradecanoylphorbol-13-acetate, respectively. The antinociceptive and sedative effects of DTA (1-100 mg/kg p.o.) were evaluated using two models of chemically-induced nociception, and the pentobarbital-induced sleeping time test, respectively. The antinociceptive mechanism of DTA was evaluated using the acetic acid writhing test with inhibitors related to pain processing pathways. The effects of DTA (10-100 mg/kg p.o.) on locomotor activity were evaluated using the rotarod test. DTA lacked cytotoxic activity (IC50 > 100 µM) on cancer cells, possessed moderate antibacterial effects against B. subtillis (MIC= 175 µM), moderate antidiarrheal and anti-inflammatory effects, and minimal vasorelaxant effects. In the formalin test, DTA showed antinociceptive effects in both phases. In the acetic acid test, DTA showed antinociceptive activity (ED50 = 50.2 ± 5.6 mg/kg) with potency similar to that of naproxen (NPX; ED50 =33.7 ± 4.5 mg/kg) an effect blocked by naloxone implicating an opioid mechanism. DTA also exerted antidiarrheal activity and showed no sedative effects or changes in locomotor activity in mice. Drug Dev Res 78 : 340-348, 2017. © 2017 Wiley Periodicals, Inc.

Effect of prebiotics of Agave salmiana fed to healthy Wistar rats.

BACKGROUND: Inulin and other fructans are synthesized and stored in mezcal agave (Agave salmiana). Fructans provide several health benefits and have excellent technological properties, but only few data report their physiological effect when added in the diet. RESULTS: Here, we studied the physiological effects of fructans obtained from A. salmiana when added in the diet of Wistar rats. Results showed favorable changes on Wistar rats when the fructans was added to their diet, including the decrease of the pH in the feces and the increase of the number of lactic acid bacteria (CFU g-1 ) (Lactobacillus spp. and Bifidobacterium spp.), even these changes were enhanced with the synbiotic diet (fructans plus B. animalis subsp. lactis). Synbiotic diet, developed changes in the reduction of cholesterol and triglycerides concentrations in serum, with statistical differences (P < 0.05). Histological analysis of colon sections showed that synbiotic diet promoted colon cells growth suggesting that fructans from A. salmiana confer beneficial health effects through gut microbiota modulation. CONCLUSION: Our data underline the advantage of targeting the gut microbiota by colonic nutrients like specific structure of fructans from A. salmiana, with their beneficial effects. More studies are necessary to define the role of fructans to develop more solid therapeutic solutions in humans. © 2016 Society of Chemical Industry.

Effect of the drying methods on the stabilization of symbiotic microbeads produced by ionic gelation.

Lactobacillus salivarius was encapsulated by ionic gelation using high polymerization degree agave fructans and sodium alginate to obtain symbiotic microspheres stabilized by different drying methods. The microbeads were characterized by physicochemical, reconstitution, microstructure, thermal, radiographic and infrared properties. The viability of L. salivarius was evaluated for one month at 4 °C and under in vitro gastrointestinal conditions. The ionic gelation-drying technique allowed an encapsulation efficiency greater than 90 %. Oven-dried microbeads showed higher viability under in vitro gastrointestinal conditions. Freeze-drying microbeads showed higher viability during storage at 4 °C, and spray-dried microbeads showed a more notable survival at 40 °C after one month of storage. All samples showed up to 7 log CFU/g of viability after in vitro digestion, which is a benefit for consumer health. It was concluded that the ionic gelation-drying process allows obtaining dry microbeads with the potential to be added to various food products.

Development and evaluation of ciprofloxacin local controlled release materials based on molecularly imprinted polymers.

The aim of this study was the molecular imprinting polymers (MIPs) assessment as a controlled release system of ciprofloxacin. The MIPs synthesis was performed by three different methods: emulsion, bulk, and co-precipitation. Lactic acid (LA) and methacrylic acid (MA) were used as functional monomers and ethylene glycol dimethacrylate as crosslinker. Also, nonimprinted polymers (NIPs) were synthesized. MIPs and NIPs were characterized by scanning electron microscopy, Fourier Transform Infrared Reflection, specific surface area, pore size, and release kinetics. Their efficiency against Staphylococcus aureus and Escherichia coli, and their cytotoxicity in dermal fibroblast cells were proven. Results show that MIPs are mesoporous materials with a pore size between 10 and 20 nm. A higher adsorption with the co-precipitation MIP with MA as a monomer was found. The release kinetics proved that a non-Fickian process occurred and that the co-precipitation MIP with LA presented the highest release rate (90.51 mg/L) in 8 h. The minimum inhibitory concentration was found between 0.031 and 0.016 mg/L for Staphylococcus aureus and between 0.004 and 0.031 mg/L for the Escherichia coli. No cytotoxicity in cellular cultures was found; also, cellular growth was favored. This study demonstrated that MIPs present promising properties for drug administration and their application in clinical practice.

Development and Validation of UPLC Tandem Mass Spectrometry Assay for Ceftibuten and Sulbactam in Human Plasma.

A sensitive and rapid ultra-performance liquid chromatography coupled with -tandem mass spectrometry (UPLC-MS/MS) method was developed and validated to determine ceftibuten (CTB) and sulbactam (SUL) in human plasma. An ACQUITY UPLC HSS T3 C18 (2.1 × 100 mm), 1.8 µm column with gradient elution of water (0.1% formic acid) and acetonitrile was used for separation at a flow rate of 0.2 mL/min. This method involves a simple sample preparation with acetonitrile. The calibration curves of CTB and SUL in plasma showed good linearity over the concentration range of 0.50-25 µg/mL and with a correlation coefficient (r2) >0.99. This method was validated in terms of selectivity, linearity, precision, accuracy and stability. High precision was obtained with coefficients of variation <15%. Excellent recovery in the range of 90-104% was achieved for CTB and SUL was 86-110%. The method has the potential utility to support pharmacometric modeling in clinical practice and biopharmaceutic studies.

Influence of feeding practices in the composition and functionality of infant gut microbiota and its relationship with health.

Establishing the infant's gut microbiota has long-term implications on health and immunity. Breastfeeding is recognized as the best practice of infant nutrition in comparison with formula feeding. We evaluated the effects of the primary feeding practices by analyzing the infant growth and the potential association with gut diseases. A cross-sectional and observational study was designed. This study included 55 mothers with infants, who were divided according to their feeding practices in breastfeeding (BF), formula feeding (FF), and combined breast and formula feeding (CF). Anthropometric measurements of the participants were recorded. Additionally, non-invasive fecal samples from the infants were collected to analyze the microbiota by sequencing, immunoglobulin A (IgA) concentration (ELISA), and volatile organic compounds (gas chromatography with an electronic nose). Results showed that the microbiota diversity in the BF group was the highest compared to the other two groups. The IgA levels in the BF group were twice as high as those in the FF group. Moreover, the child´s growth in the BF group showed the best infant development when the data were compared at birth to the recollection time, as noted by the correlation with a decreased concentration of toxic volatile organic compounds. Interestingly, the CF group showed a significant difference in health status when the data were compared with the FF group. We conclude that early health practices influence children's growth, which is relevant to further research about how those infants' health evolved.

Anti-biofilm activity of silver nanoparticles against different microorganisms.

Biofilms confer protection from adverse environmental conditions and can be reservoirs for pathogenic organisms and sources of disease outbreaks, especially in medical devices. The goal of this research was to evaluate the anti-biofilm activities of silver nanoparticles (AgNPs) against several microorganisms of clinical interest. The antimicrobial activity of AgNPs was tested within biofilms generated under static conditions and also under high fluid shears conditions using a bioreactor. A 4-log reduction in the number of colony-forming units of Pseudomonas aeruginosa was recorded under turbulent fluid conditions in the CDC reactor on exposure to 100 mg ml(-1) of AgNPs. The antibacterial activity of AgNPs on various microbial strains grown on polycarbonate membranes is reported. In conclusion, AgNPs effectively prevent the formation of biofilms and kill bacteria in established biofilms, which suggests that AgNPs could be used for prevention and treatment of biofilm-related infections. Further research and development are necessary to translate this technology into therapeutic and preventive strategies.

Multispecies oral biofilm and identification of components as treatment target.

Endodontic infections involve a multispecies biofilm, making it difficult to choose an antimicrobial treatment. Characteristics such as the pathogens involved and number of microorganisms, nutrients, material surface to develop the biofilm, flow and oxygenation conditions are important for biofilm development using in vitro models. OBJECTIVE: To develop a standardized biofilm model, which replicates the main features (chemical, microbiological, and topographical) of an infected root canal tooth to detect components as treatment target. DESIGN: Clinical strains of Enterococcus faecalis, Candida albicans, and Actinomyces israelii were isolated, and a multispecies biofilm was developed using continuous laminar flow reactors under anaerobic conditions in human dental roots. The microbiological composition was determined by counting colony-forming units and scanning electron microscope micrographs. In addition, the chemical composition of the exopolymeric matrix was determined by vibrational Raman spectroscopy and liquid chromatography of biofilm supernatant treated with enzyme. RESULTS: E. faecalis turned out to be the main microorganism in mature biofilm, this was related to the presence of ß-galactosidase detected by vibrational Raman spectroscopy. After the enzymatic treatment of the extracellular polymeric substance, the presence of mannose and glucose was established. CONCLUSIONS: The present work contributes to better understanding of standard conditions to develop a multispecies biofilm in human dental roots, which could have an impact on the generation of new root canal disinfection techniques in endodontic pathologies.

A systematic review of the protein composition of whole saliva in subjects with healthy periodontium compared with chronic periodontitis.

CONTEXT: Periodontitis is a chronic multifactorial inflammatory disease linked to oral microbiota dysbiosis. This disease progresses to infection that stimulates a host immune/inflammatory response, with progressive destruction of the tooth-supporting structures. OBJECTIVE: This systematic review aims to present a robust critical evaluation of the evidence of salivary protein profiles for identifying oral diseases using proteomic approaches and summarize the use of these approaches to diagnose chronic periodontitis. DATA SOURCES: A systematic literature search was conducted from January 1st, 2010, to December 1st, 2022, based on PICO criteria following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and by searching the three databases Science Direct, Scopus, and Springer Link. STUDY SELECTION: According to the inclusion criteria, eight studies were identified to analyze the proteins identified by proteomics. RESULTS: The protein family S100 was identified as the most abundant in patients with chronic periodontitis. In this family, an increased abundance of S100A8 and S100A9 from individuals with the active disease was observed, which strongly relates to the inflammatory response. Moreover, the ratio S100A8/S100A9 and the metalloproteinase-8 in saliva could differentiate distinct periodontitis groups. The changes in protein profile after non-surgical periodontal therapy improved the health of the buccal area. The results of this systematic review identified a set of proteins that could be used as a complementary tool for periodontitis diagnosis using salivary proteins. CONCLUSION: Biomarkers in saliva can be used to monitor an early stage of periodontitis and the progression of the disease following therapy.

Use of a Cellulase from Trichoderma reesei as an Adjuvant for Enterococcus faecalis Biofilm Disruption in Combination with Antibiotics as an Alternative Treatment in Secondary Endodontic Infection.

Apical periodontitis is an inflammation leading to the injury and destruction of periradicular tissues. It is a sequence of events that starts from root canal infection, endodontic treatment, caries, or other dental interventions. Enterococcus faecalis is a ubiquitous oral pathogen that is challenging to eradicate because of biofilm formation during tooth infection. This study evaluated a hydrolase (CEL) from the fungus Trichoderma reesei combined with amoxicillin/clavulanic acid as a treatment against a clinical E. faecalis strain. Electron microscopy was used to visualize the structure modification of the extracellular polymeric substances. Biofilms were developed on human dental apices using standardized bioreactors to evaluate the antibiofilm activity of the treatment. Calcein and ethidium homodimer assays were used to evaluate the cytotoxic activity in human fibroblasts. In contrast, the human-derived monocytic cell line (THP-1) was used to evaluate the immunological response of CEL. In addition, the secretion of the pro-inflammatory cytokines IL-6 and TNF-α and the anti-inflammatory cytokine IL-10 were measured by ELISA. The results demonstrated that CEL did not induce the secretion of IL-6 and TNF-α when compared with lipopolysaccharide used as a positive control. Furthermore, the treatment combining CEL with amoxicillin/clavulanic acid showed excellent antibiofilm activity, with a 91.4% reduction in CFU on apical biofilms and a 97.6% reduction in the microcolonies. The results of this study could be used to develop a treatment to help eradicate persistent E. faecalis in apical periodontitis.

Modulation of the Altered Intestinal Microbiota by Use of Antibiotics with a Novel Synbiotic on Wistar Rats.

The use of antibiotics unbalances the intestinal microbiota. Probiotics, prebiotics, and synbiotics are alternatives for these unbalances. The effects of a new synbiotic composed of probiotic Saccharomyces boulardii CNCM I-745 and fructans from Agave salmiana (fAs) as prebiotics were assessed to modulate the intestinal microbiota. Two probiotic presentations, the commercial probiotic (CP) and the microencapsulated probiotic (MP) to improve those effects, were used to prepare the synbiotics and feed Wistar rats subjected to antibiotics (AB). Eight groups were studied, including five controls and three groups to modulate the microbiota after the use of antibiotics: G5: AB + MP-synbiotic, G6: AB + CP-synbiotic, and G8: AB + fAs. All treatments were administered daily for 7 days. On days 7 and 21, euthanasia was performed, cecum tissue was recovered and used to evaluate histological analysis and to study microphotograph by TEM, and finally, bacterial DNA was extracted and 16S rRNA gene metabarcode sequencing was performed. Histological analysis showed less epithelial damage and more abundance of the intestinal microbiota in the groups G5, G6, and G8 in comparison with the AB control group after 7 days. Microphotograph of the cecum at 2 weeks post treatment showed that G5 and G6 presented beneficial effects in epithelial reconstruction. Interestingly, in the groups that used the synbiotic without AB (G3 and G4) in addition to contributing to the recovery of the autochthonous microbiota, it promotes the development of beneficial microorganisms; those results were also achieved in the groups that used the synbiotic with AB enhancing the bacterial diversity and regulating the impact of AB.

Radiosterilized Pig Skin, Silver Nanoparticles and Skin Cells as an Integral Dressing Treatment for Burns: Development, Pre-Clinical and Clinical Pilot Study.

Radiosterilized pig skin (RPS) has been used as a dressing for burns since the 1980s. Its similarity to human skin in terms of the extracellular matrix (ECM) allows the attachment of mesenchymal stem cells, making it ideal as a scaffold to create cellularized constructs. The use of silver nanoparticles (AgNPs) has been proven to be an appropriate alternative to the use of antibiotics and a potential solution against multidrug-resistant bacteria. RPS can be impregnated with AgNPs to develop nanomaterials capable of preventing wound infections. The main goal of this study was to assess the use of RPS as a scaffold for autologous fibroblasts (Fb), keratinocytes (Kc), and mesenchymal stem cells (MSC) in the treatment of second-degree burns (SDB). Additionally, independent RPS samples were impregnated with AgNPs to enhance their properties and further develop an antibacterial dressing that was initially tested using a burn mouse model. This protocol was approved by the Research and Ethics Committee of the INRLGII (INR 20/19 AC). Transmission electron microscopy (TEM) and dynamic light scattering (DLS) analysis of the synthesized AgNPs showed an average size of 10 nm and rounded morphology. Minimum inhibitory concentrations (MIC) and Kirby-Bauer assays indicated that AgNPs (in solution at a concentration of 125 ppm) exhibit antimicrobial activity against the planktonic form of S. aureus isolated from burned patients; moreover, a log reduction of 1.74 ± 0.24 was achieved against biofilm formation. The nanomaterial developed with RPS impregnated with AgNPs solution at 125 ppm (RPS-AgNPs125) facilitated wound healing in a burn mouse model and enhanced extracellular matrix (ECM) deposition, as analyzed by Masson's staining in histological samples. No silver was detected by energy-dispersive X-ray spectroscopy (EDS) in the skin, and neither by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) in different organs of the mouse burn model. Calcein/ethidium homodimer (EthD-1), 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT), and scanning electron microscopy (SEM) analysis demonstrated that Fb, Kc, and MSC could attach to RPS with over 95% cell viability. Kc were capable of releasing FGF at 0.5 pg above control levels, as analyzed by ELISA assays. An autologous RPS-Fb-Kc construct was implanted in a patient with SDB and compared to an autologous skin graft. The patient recovery was assessed seven days post-implantation, and the patient was followed up at one, two, and three months after the implantation, exhibiting favorable recovery compared to the gold standard, as measured by the cutometer. In conclusion, RPS effectively can be used as a scaffold for the culture of Fb, Kc, and MSC, facilitating the development of a cellularized construct that enhances wound healing in burn patients.

Antibacterial activity, inflammatory response, coagulation and cytotoxicity effects of silver nanoparticles.

The incorporation of nanoparticles (NPs) in industrial and biomedical applications has increased significantly in recent years, yet their hazardous and toxic effects have not been studied extensively. Here, we studied the effects of 24 nm silver NPs (AgNPs) on a panel of bacteria isolated from medical devices used in a hospital intensive care unit. The cytotoxic effects were evaluated in macrophages and the expression of the inflammatory cytokines IL-6, IL-10 and TNF-α were quantified. The effects of NPs on coagulation were tested in vitro in plasma-based assays. We demonstrated that 24 nm AgNPs were effective in suppressing the growth of clinically relevant bacteria with moderate to high levels of antibiotic resistance. The NPs had a moderate inhibitory effect when coagulation was initiated through the intrinsic pathway. However, these NPs are cytotoxic to macrophages and are able to elicit an inflammatory response. Thus, beneficial and potential harmful effects of 24 nm AgNPs on biomedical devices must be weighed in further studies in vivo. From the Clinical Editor: The authors of this study demonstrate that gallic acid reduced 24 nm Ag NPs are effective in suppressing growth of clinically relevant antibiotic resistant bacteria. However, these NPs also exhibit cytotoxic properties to macrophages and may trigger an inflammatory response. Thus, the balance of beneficial and potential harmful effects must be weighed carefully in further studies.