Physicochemical Characterization and Thermodynamic Analysis of Avocado Oil Enhanced with Haematococcus pluvialis Extract.

The consumption of fatty acids offers significant health benefits; however, they are prone to degradation by environmental factors. One method to preserve these fatty acids is the addition of synthetic antioxidants. This study focuses on the determination of peroxide and MDA formation rates at temperatures of 25 °C, 45 °C, and 65 °C. The oxidative stability of cold-pressed avocado oil was evaluated using pure astaxanthin, TBHQ, and H. pluvialis extract at concentrations of 100, 500, and 1000 ppm. Kinetic models and thermodynamic analysis were applied to determine the oxidation rate and compare the antioxidant effects of H. pluvialis extract with astaxanthin and TBHQ. The Arrhenius model was used to estimate activation energy (Ea), enthalpy, entropy, and free energy. Avocado oil with 500 ppm of H. pluvialis extract showed antioxidant effects comparable to TBHQ and pure astaxanthin. The activation energy of plain avocado oil was 40.47 kJ mol-1, while with H. pluvialis extract, it was 54.35 kJ mol-1. These findings suggest that H. pluvialis extract offers effective antioxidant properties and could serve as a natural alternative to synthetic antioxidants in food applications, despite the limitations of unprotected astaxanthin.

Effect of Physical Separation with Ultrasound Application on Brewers' Spent Grain to Obtain Powders for Potential Application in Foodstuffs.

Brewers' spent grain (BSG) is the primary by-product of beer production, and its potential use in food products is largely dependent on its processing, given its moisture content of up to 80%. This study aimed to evaluate the effects of physical separation with ultrasound application on the color, total phenolic content (TPC), antioxidant activity, proximate composition, total dietary fibers, and particle size distribution of BSG powders. Wet BSG (W) was subjected to two processes: one without ultrasound (A) and one with ultrasound (B). Both processes included pressing, convective air-drying, sieving, fraction separation (A1 and B1 as coarse with particles ≥ 2.36 mm; A2 and B2 as fine with particles < 2.36 mm), and milling. The total color difference compared to W increased through both processes, ranging from 1.1 (B1 vs. A1) to 5.7 (B1 vs. A2). There was no significant difference in TPC, but process B powders, particularly B2, showed lower antioxidant activity against ABTS•+, likely due to the release of antioxidant compounds into the liquid fraction during pressing after ultrasound treatment. Nonetheless, process B powders exhibited a higher content of soluble dietary fibers. In conclusion, ultrasound application shows potential for further extraction of soluble fibers. However, process A might be more practical for industrial and craft brewers. Further studies on the use of the resulting BSG powders as food ingredients are recommended.

Use of ultrasound to improve the activity of cyclodextrin glycosyltransferase in the producing of ß-cyclodextrins: Impact on enzyme activity, stability and insights into changes on enzyme macrostructure.

This work explored the impact of ultrasound (US) on the activity, stability, and macrostructural conformation of cyclodextrin glycosyltransferase (CGTase) and how these changes could maximize the production of ß-cyclodextrins (ß-CDs). The results showed that ultrasonic pretreatment (20 kHz and 38 W/L) at pH 6.0 promoted increased enzymatic activity. Specifically, after sonication at 25 °C/30 min, there was a maximum activity increase of 93 % and 68 % when biocatalysis was carried out at 25 and 55 °C, respectively. For activity measured at 80 °C, maximum increase (31 %) was observed after sonication at 25 °C/60 min. Comparatively, US pretreatment at low pH (pH = 4.0) resulted in a lower activity increase (max. 28 %). These activation levels were maintained after 24 h of storage at 8 °C, suggesting that changes on CGTase after ultrasonic pretreatment were not transitory. These pretreatments altered the conformational structure of CGTase, revealed by an up to 11 % increase in intrinsic fluorescence intensity, and resulted in macrostructural modifications, such as a decrease in particle size and polydispersion index (up to 85 % and 45.8 %, respectively). Therefore, the sonication of CGTase under specific conditions of pH, time, and temperature (especially at pH 6.0/ 30 min/ 25 °C) promotes macrostructural changes in CGTase that induce enzyme activation and, consequently, higher production of ß-CDs.

Synthesis of multi-layer graphene oxide from HCl-treated coke and Brazilian coals by sulfuric acid thermal exfoliation and ozone oxidation.

This study involved the synthesis and characterization of graphene oxide (GO) from mineral coke and bituminous coal. HCl treated and non-HCl treated ultrafine powder obtained from both precursors were treated with H2SO4, followed by thermal treatment, and oxidation with ozone and ultra-sonication for GO production. The synthesized materials were characterized using Fourier transform infrared spectroscopy (FTIR), zeta potential (ZP), particle size distribution (PSD), transmission electron microscopy (TEM), X-ray diffraction (XRD) and Raman spectroscopy. The results confirmed the exfoliation of the material primarily at the edges of its structure and the formation of multilayer graphene oxide (GO) from mineral coke and bituminous coal. Furthermore, it was found that carbonaceous materials with graphitic morphology are easier to exfoliate and oxidize, leading to the production of higher quality graphene oxide. Therefore, the GO synthesized from mineral coke exhibited the best quality in this study. The methodology used proposes an innovative approach, offering a faster, more economical, and environmentally friendly synthesis compared to the traditional Hummers' method, thereby adding value to other raw materials that can be utilized in this process, such as Brazilian coke and coal.

Sonication protocols and their contributions to the microbiological diagnosis of implant-associated infections: a review of the current scenario.

Addressing the existing problem in the microbiological diagnosis of infections associated with implants and the current debate about the real power of precision of sonicated fluid culture (SFC), the objective of this review is to describe the methodology and analyze and compare the results obtained in current studies on the subject. Furthermore, the present study also discusses and suggests the best parameters for performing sonication. A search was carried out for recent studies in the literature (2019-2023) that addressed this research topic. As a result, different sonication protocols were adopted in the studies analyzed, as expected, and consequently, there was significant variability between the results obtained regarding the sensitivity and specificity of the technique in relation to the traditional culture method (periprosthetic tissue culture - PTC). Coagulase-negative Staphylococcus (CoNS) and Staphylococcus aureus were identified as the main etiological agents by SFC and PTC, with SFC being important for the identification of pathogens of low virulence that are difficult to detect. Compared to chemical biofilm displacement methods, EDTA and DTT, SFC also produced variable results. In this context, this review provided an overview of the most current scenarios on the topic and theoretical support to improve sonication performance, especially with regard to sensitivity and specificity, by scoring the best parameters from various aspects, including sample collection, storage conditions, cultivation methods, microorganism identification techniques (both phenotypic and molecular) and the cutoff point for colony forming unit (CFU) counts. This study demonstrated the need for standardization of the technique and provided a theoretical basis for a sonication protocol that aims to achieve the highest levels of sensitivity and specificity for the reliable microbiological diagnosis of infections associated with implants and prosthetic devices, such as prosthetic joint infections (PJIs). However, practical application and additional complementary studies are still needed.

High-intensity ultrasound influences the probiotic fermentation of Baru almond beverages and impacts the bioaccessibility of phenolics and fatty acids, sensory properties, and in vitro biological activity.

High-intensity ultrasound (HIUS, 20 kHz, 450 W, 6 min) was used as an alternative to the pasteurization of a water-soluble Baru almond extract (WSBAE). Then, probiotic fermented beverages (Lacticaseibacillus casei) were processed and evaluated during storage (7 °C, 28 days). Four formulations were prepared: RAW (untreated [no pasteurization or ultrasound] and unfermented WSBAE), PAST (pasteurized WSBAE fermented with probiotic), U-BEF (WSBAE added with probiotic, submitted to ultrasound, and fermented), and U-AFTER (WSBAE submitted to ultrasound, added with probiotic, and fermented). PAST and HIUS-treated beverages had similar microbiological quality. The PAST formulation showed decreased monounsaturated fatty acids, compromised health indices, and had the lowest consistency. U-AFTER showed higher concentrations of lactic and acetic acids, lower bioaccessibility for most phenolics and fatty acids, and reduced consumer acceptance. U-BEF had the fermentation time reduced by 13.64%, higher probiotic survival during storage and simulated gastrointestinal conditions, and higher bioaccessibility of phenolics and fatty acids during storage. Furthermore, it presented higher in vitro antidiabetic properties and improved consistency and stability. Finally, U-BEF had improved volatile compound composition, resulting in increased sensory acceptance and improved sensory properties. Our results indicate that the HIUS applied after probiotic addition may be a suitable alternative to pasteurization in the processing of fermented beverages, resulting in reduced fermentation times and improved technological, sensory, and biological properties.

High-intensity ultrasound improves color and oxidative stability of beef from grain-fed and pasture-fed Nellore cattle.

This research aimed to evaluate the influence of high-intensity ultrasound (HIU) levels (control: 0; high: 747.79; ultra-high: 1344.17 Wcm-2) on pH, instrumental color (redness, R630/580, hue angle and chroma) and oxidative stability (lipid and protein oxidation) of Psoas major (PM) muscle from Nellore cattle raised in two feeding systems: grain and pasture. Using a structural equation modeling (SEM) approach, the relations (P > 0.05) between exogenous (HIU levels) and endogenous (pH, color, lipid and protein oxidation) variables were observed. In beef from grain-fed animals the pH was directly and negatively related to lipid oxidation (γ = -0.321), hue angle (γ = -0.847) and chroma (γ = -0.442) and protein oxidation (γ = -0.752). In PM from pasture-fed HIU exhibited a negative relation with lipid (γ = -0.144) and protein (γ = -0.743) oxidation, suggesting a possible positive influence on the oxidative stability of meat and a positive relation with redness (γ = 0.197) and R630/580 (γ = 0.379). The HIU positively influenced the color and oxidative stability of beef from Bos indicus cattle, and a synergistic effect of HIU and feeding system on beef from pasture-fed animals.

Contribution of Sonication to the Identification of Megaprosthesis Infection in Culture Negative Oncologic Patient.

Conventional central osteosarcoma mainly affects the metaphysis of long bones in young people. The use of megaprostheses in oncological patients has increased in recent years. However, this type of surgery is not exempt from complications, with infections being the most common. In recent years, the presence of biofilm-forming bacteria has increased. Biofilm characteristics allow bacteria to resist hostile environmental conditions. The application of long wave ultrasound (process known as sonication) on the rescued inert material before culture interrupts the biofilm and generates a significantly higher recovery of bacterial growth compared to conventional tissue culture. We present the case of a 12-year-old patient with osteosarcoma of the femur, who, after surgery, developed a prosthetic infection detected by sonication, with negative soft tissue culture.

Sonication as a tool for disrupting biofilms and recovering microorganisms in bladder catheters / Sonicação como uma ferramenta para romper biofilmes e recuperar microrganismos em cateteres vesicais

Abstract Introduction: Urinary catheter-related infection is commonly associated with bacterial biofilm. The impact of anaerobes is unknown, but their detection in the biofilm on this device has not been previously reported. This study aimed to evaluate the capability to recovery strict, facultative, and aerobic microorganisms in patients using bladder catheters from ICUs using conventional culture, sonication, urinary analysis, and mass spectrometry. Methods: Parallel, sonicated bladder catheters from 29 critically ill patients were compared with their routine urine culture. Identification was performed using matrix-assisted laser desorption/ionization with time-of-flight mass spectrometry. Results: The positivity rate in urine (n = 2, 3.4%) was lower than that in sonicated catheters (n = 7, 13.8%). Conclusion: Bladder catheter sonication showed more positive culture results than urine samples for anaerobic and aerobic microorganisms. The role of anaerobes in urinary tract infection and catheter biofilm is discussed.

Resumo Introdução: A infecção relacionada ao cateter urinário é comumente associada ao biofilme bacteriano. O impacto dos anaeróbios é desconhecido, mas sua detecção no biofilme deste dispositivo não foi relatada anteriormente. Este estudo teve como objetivo avaliar a capacidade de recuperar microrganismos estritos, facultativos e aeróbios em pacientes que utilizam cateteres vesicais de UTIs utilizando cultura convencional, sonicação, análise urinária e espectrometria de massa. Métodos: Paralelamente, foram comparados cateteres vesicais sonicados de 29 pacientes gravemente enfermos com sua urocultura de rotina. A identificação foi realizada utilizando dessorção/ionização a laser assistida por matriz com espectrometria de massa por tempo de voo. Resultados: A taxa de positividade na urina (n = 2; 3,4%) foi inferior à dos cateteres sonicados (n = 7; 13,8%). Conclusão: A sonicação do cateter vesical apresentou resultados de cultura mais positivos do que as amostras de urina para microrganismos anaeróbios e aeróbios. É discutido o papel dos anaeróbios na infecção do trato urinário e no biofilme do cateter.

The Development of Fe3O4-Monolithic Resorcinol-Formaldehyde Carbon Xerogels Using Ultrasonic-Assisted Synthesis for Arsenic Removal of Drinking Water.

Inorganic arsenic in drinking water from groundwater sources is one of the potential causes of arsenic-contaminated environments, and it is highly toxic to human health even at low concentrations. The purpose of this study was to develop a magnetic adsorbent capable of removing arsenic from water. Fe3O4-monolithic resorcinol-formaldehyde carbon xerogels are a type of porous material that forms when resorcinol and formaldehyde (RF) react to form a polymer network, which is then cross-linked with magnetite. Sonication-assisted direct and indirect methods were investigated for loading Fe3O4 and achieving optimal mixing and dispersion of Fe3O4 in the RF solution. Variations of the molar ratios of the catalyst (R/C = 50, 100, 150, and 200), water (R/W = 0.04 and 0.05), and Fe3O4 (M/R = 0.01, 0.03, 0.05, 0.1, 0.15, and 0.2), and thermal treatment were applied to evaluate their textural properties and adsorption capacities. Magnetic carbon xerogel monoliths (MXRF600) using indirect sonication were pyrolyzed at 600 °C for 6 h with a nitrogen gas flow in the tube furnace. Nanoporous carbon xerogels with a high surface area (292 m2/g) and magnetic properties were obtained. The maximum monolayer adsorption capacity of As(III) and As(V) was 694.3 µg/g and 1720.3 µg/g, respectively. The incorporation of magnetite in the xerogel structure was physical, without participation in the polycondensation reaction, as confirmed by XRD, FTIR, and SEM analysis. Therefore, Fe3O4-monolithic resorcinol-formaldehyde carbon xerogels were developed as a potential adsorbent for the effective removal of arsenic with low and high ranges of As(III) and As(V) concentrations from groundwater.

Unexpected Bacteriological Finding Using Sonication in Revision Spine Surgery (Report of Two Cases).

The number of spine surgeries around the world is increasing in recent years. Each time, new techniques and minimal invasive procedures are developing. However, the incidence of postoperative spinal infections (PSII) ranges from 0.7% to 20%. In cases of infection, identification of the pathogen is essential to apply the appropriate antimicrobial treatment. Most of the usual techniques are based on the recovery of samples from the periprosthetic tissue followed by inoculation in culture media. In the last years, the presence of biofilm-forming bacteria has increased, which has the ability to decrease the sensitivity of the traditional culture method. The application of sonication prior to culture on the rescued inert material, disrupts the biofilm and generates a significantly higher recovery of bacterial growth compared to conventional tissue culture. We present a case series from our service of patients undergoing apparently aseptic lumbar spine revision surgery with positive culture by sonication.

Epidemiología de las infecciones post osteosíntesis detectadas por baño de ultrasonido en el Servicio de Traumatología del Hospital Universitario de Caracas / Post osteosinthesis infections epidemiology by ultrasound bath in the trauma service of the University Hospital of Caracas

El objetivo de este trabajo es determinar la epidemiología de la infección post osteosíntesis a través de cultivos de fluidos sonicados en los pacientes del Hospital Universitario de Caracas en el período comprendido entre noviembre 2021-noviembre 2022. Se realizó un estudio observacional de tipo, serie de casos, a través de la revisión de historias médicas de todos los casos que acudieron con diagnóstico de infección post osteosíntesis a fin de determinar cuál agente causal fue el más común, factores de riesgo asociados y tratamiento de elección. Se incluyeron 10 pacientes, 70% de sexo masculino y edad promedio de 40,6±17,9 años. Los gérmenes aislados en el cultivo convencional fueron el SAMS, SAMR, Enterobacter cloacae, Staphylococcus coagulasa negativo (10,0% cada uno), el 60,0% de los cultivos en esta modalidad fueron negativos, en el cultivo de fluidos por baño de ultrasonido, el germen más frecuente fue el SAMR en el 30% de los casos, seguido del SAMS con 20%, en menor medida un caso de Staphylococcus coagulasa negativo y una infección polimicrobiana compuesta por K. pneumoniae, E. cloacae y Enterococo sp. El tratamiento médico consistió en antibioticoterapia vía endovenosa, se realizó de acuerdo al antibiograma obtenido del cultivo, el más empleado fue la cefazolina en 30% (en casos de SAMS), seguido de la vancomicina + meropenem y la vancomicina aislada en 20%. Todos los pacientes cumplieron tratamiento al menos por 4 semanas con evolución satisfactoria(AU)

The objective of this work is to determine the epidemiology of post-osteosynthesis infection through sonicated fluid cultures in patients at the Hospital Universitario de Caracas in the period between November 2021 and November 2022. An observational study of type, series of cases, through the review of the medical records of all the cases that presented with a diagnosis of post-osteosynthesis infection in order to determine which causative agent was the most common, associated risk factors and treatment of choice. 10 patients were included, 70% male and mean age 40.6 ± 17.9 years. The germs isolated in the conventional culture were SAMS, SAMR, Enterobacter cloacae, coagulase-negative Staphylococcus (10.0% each), 60.0% of the cultures in this modality were negative, in the culture of fluids by bath of On ultrasound, the most frequent germ was MRSA in 30% of cases, followed by SAMS with 20%, to a lesser extent a case of coagulase-negative Staphylococcus and a polymicrobial infection made up of K. pneumoniae, E. cloacae and Enterococcus sp. The medical treatment consisted of intravenous antibiotic therapy, it was carried out according to the antibiogram obtained from the culture, the most used was cefazolin in 30% (in cases of SAMS), followed by vancomycin + meropenem and vancomycin alone in 20%. All patients complied with treatment for at least 4 weeks with satisfactory evolution(AU)

Effect of ultrasound on Pseudoneochloris marina and Chlorella zofingiensis growth.

The present work evaluated the ultrasound (US) effects on the growth of Pseudoneochloris marina and Chlorella zofingiensis. For P. marina, US treatment did not increase cell proliferation and reduced cell density when used for 60 min (exponential phase, for 5 days), indicating a possible occurrence of cell damage. For C. zofingiensis, the application of discontinuous US for 10 min resulted in an increase of 65 % in biomass concentration compared to the control. These distinct behaviors indicate that microalgae species react differently to physical stimuli. After US treatment, a reduction of carotenoid, chlorophyll, lipid and protein concentrations was observed, which may be related to changes in the metabolic pathways to produce these compounds. Overall, the results of the present study show the potential of discontinuous US to enhance microalgae cell proliferation.

Investigation on formulation parameters of donepezil HCl loaded solid lipid nanoparticles

Abstract Donepezil-HCl is a member of the acetylcholinesterase inhibitors that is indicated for the symptomatic treatment of Alzheimer's disease (AD) and has many side effects. In this study, to reduce the side effects of Donepezil-HCl and increase the penetration of the drug through the blood-brain barrier, we aimed to design a solid lipid nanoparticle (SLN) formulation. The effects of the different formulation parameters, such as homogenization speed, sonication time, lipid and drug concentration, surfactant type and concentration, and volume of the aqueous phase, were assessed for optimization. The particle size and PDI increased with increasing lipid concentration but decreased with increasing amounts of surfactant (Tween 80) and co-surfactant (lecithin). When the homogenization rate and sonication time increased, the particle size decreased and the encapsulation efficiency increased. The optimized formulation exhibited particle size, PDI, encapsulation efficiency, and zeta potential of 87.2±0.11 nm; 0.22±0.02; 93.84±0.01 %; -17.0±0.12 mV respectively. The in vitro release investigation revealed that approximately 70% of Donepezil-HCl was cumulatively released after 24 hours. TEM analysis proved that spherical and smooth particles were obtained and formulations had no toxic effect on cells. The final optimized formulation could be a candidate for Donepezil-HCl application in Alzheimer's treatment with reduced side effects and doses for patients

Effects of Molarity and Storage Time of MWCNTs on the Properties of Cement Paste.

Nowadays, nanomaterials in cement pastes are among the most important topics in the cement industry because they can be used for several applications. For this reason, this work presents a study about the influence of changing the molarity of dispersed multiple wall carbon nanotubes (MWCNTs) and varying the number of storage days on the mechanical properties of the cement paste. To achieve this objective, dispersions of 0.35% MWCNTs, varying the molarity of the surfactant as 10 mM, 20 mM, 40 mM, 60 mM, 80 mM, and 100 mM, were performed. The mixture of materials was developed using the sonication process; furthermore, materials were analyzed using UV-Vis, Z-potential, and Raman spectroscopy techniques. Materials with a molarity of 10 mM exhibited the best results, allowing them to also be stored for four weeks. Regarding the mechanical properties, an increase in the elastic modulus was observed when MWCNTs were included in the cement paste for all storage times. The elastic modulus and the maximum stress increased as the storage time increased.

Detection of Microorganisms in Clinical Sonicated Orthopedic Devices Using Conventional Culture and qPCR.

Objective To evaluate the sensitivity and specificity of the quantitative real-time polymerase chain reaction (qPCR) for 16S rDNA gene screening using sonicated fluid from orthopedic implants. Methods A retrospective study was conducted on 73 sonicated fluids obtained from patients with infection associated with orthopedic implants. The samples were subjected to conventional culture and molecular testing using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and qPCR for 16S rDNA . The cycle threshold values were used to define a cut-off of the qPCR of the 16S rDNA for negative and positive cultures. Results No statistical differences were observed between the positive and negative culture groups based on the time from the first surgery to infection ( p = 0.958), age ( p = 0.269), or general comorbidities. Nevertheless, a statistical difference was found between the mean duration of antibiotic use before device removal (3.41 versus 0.94; p = 0.016). Bacterial DNA was identified in every sample from the sonicated fluids. The median cycle thresholds of the positive and negative cultures were of 25.6 and 27.3 respectively ( p < 0.001). As a diagnostic tool, a cycle threshold cut-off of 26.89 demonstrated an area under the curve of the receiver operating characteristic of 0.877 ( p ≤ 0.001). Conclusion The presence of antimicrobial agents for more than 72 hours decreased culture positivity, but did not influence the qPCR results. Despite this, amplification of the 16S rDNA may overestimate infection diagnosis.

Determination of gibberellic acid and abscisic acid in (Zea mays L.) (ICA-V305) seeds germinated using dynamic sonication assisted solvent extraction and maceration.

Phytohormones are molecules responsible for growth, development, and metabolism regulation in plants. Gibberellic acid (GA3) and abscisic acid (ABA) are the main phytohormones involved in seed germination. Notably, it should be a highlight that GA3 induces germination, whereas ABA inhibits it. For this reason, it is important to calculate the concentration of these two phytohormones during seeds germination. Firstly, the maize seeds (MS) were germinated and samples of these were taken at different imbibition times, after that, methanol extracts were obtained using two methods of dynamic solvent extraction assisted by sonication (DSASE) and a traditional extraction method (maceration); finally, to estimate the concentration of GA3 and ABA a high performance liquid chromatographic method was used. The results of this study showed that the three extraction methods used, allowed quantifying GA3 and ABA during the maize germination time studied. However, of the two extraction methods employed, DSASE was the best technique because higher concentrations of GA3 and ABA were found. Therefore, it is important to continue using this green chemistry methodology for these and other analyses.•The extraction protocol developed was based on dynamic sonication-assisted solvent extraction.•The chromatographic method used allowed the simultaneous determination of two phytohormones with different physicochemical properties in maize seeds.•This methodology offers good sensitivity, linearity, precision, reproducibility and suitable detection and quantification limits.

Detection of Microorganisms in Clinical Sonicated Orthopedic Devices Using Conventional Culture and qPCR / Detecção de microrganismos em dispositivos ortopédicos sonicados clínicos usando cultura convencional e qPCR

Abstract Objective To evaluate the sensitivity and specificity of the quantitative real-time polymerase chain reaction (qPCR) for 16S rDNA gene screening using sonicated fluid from orthopedic implants. Methods A retrospective study was conducted on 73 sonicated fluids obtained from patients with infection associated with orthopedic implants. The samples were subjected to conventional culture and molecular testing using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and qPCR for 16S rDNA. The cycle threshold values were used to define a cut-off of the qPCR of the 16S rDNA for negative and positive cultures. Results No statistical differences were observed between the positive and negative culture groups based on the time from the first surgery to infection (p= 0.958), age (p =0.269), or general comorbidities. Nevertheless, a statistical difference was found between the mean duration of antibiotic use before device removal (3.41 versus 0.94; p =0.016). Bacterial DNA was identified in every sample from the sonicated fluids. The median cycle thresholds of the positive and negative cultures were of 25.6 and 27.3 respectively (p< 0.001). As a diagnostic tool, a cycle threshold cut-off of 26.89 demonstrated an area under the curve of the receiver operating characteristic of 0.877 (p≤ 0.001). Conclusion The presence of antimicrobial agents for more than 72 hours decreased culture positivity, but did not influence the qPCR results. Despite this, amplification of the 16S rDNA may overestimate infection diagnosis.

Resumo Objetivo Avaliar a sensibilidade e a especificidade da reação em cadeia de polimerase em tempo real quantitativa (quantitative real-time polymerase chain reaction, qPCR, em inglês) para a triagem do gene rDNA 16S, com a utilização do fluido sonicado de implantes ortopédicos. Métodos Um estudo retrospectivo foi realizado em 73 fluidos sonicados obtidos de pacientes com infecção associada aos implantes ortopédicos. As amostras foram submetidas a cultura convencional e a teste molecular utilizando ionização e dessorção a laser assistida por matriz com espectrometria de massa por tempo de voo (matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, MALDI-TOF MS, em inglês) e qPCR para o gene rDNA 16S. Os valores limiares do ciclo foram usados para definir um ponto de corte para a qPCR do gene rDNA 16S para culturas negativas e positivas. Resultados Não foram observadas diferenças estatísticas entre os grupos de cultura positiva e negativa com base no tempo desde a primeira cirurgia até a infecção (p= 0,958), na idade (p= 0,269), ou nas comorbidades em geral. No entanto, uma diferença estatística foi encontrada entre a duração média do uso de antibióticos antes da remoção do dispositivo (3,41 versus 0,94; p= 0,016). O DNA bacteriano foi identificado em todas as amostras dos fluidos sonicados. Os limiares do ciclo médio de culturas positivas e negativas foram de 25,6 e 27,3, respectivamente (p< 0,001). Como uma ferramenta de diagnóstico, um corte do limite do ciclo de 26,89 demonstrou uma área sob a curva da característica de operação do receptor de 0,877 (p ≤ 0,001). Conclusão A presença de agentes antimicrobianos por mais de 72 horas diminuiu a positividade da cultura, mas não influenciou os resultados da qPCR. Apesar disso, a amplificação do rDNA 16S pode sobrestimar o diagnóstico de infecção.

Can droplet size influence antibacterial activity in ultrasound-prepared essential oil nanoemulsions?

Essential oil nanoemulsion may have improved antibacterial properties over pure oil and can be used for food preservation. Ultrasonic cavitation is the most common mechanism for producing nanoemulsions, and the impact of processing parameters on droplet properties needs to be elucidated. A systematic literature search was performed in four databases (Science Direct, Web of Science, Scopus and PubMed), and 987 articles were found, 16 of which were eligible for the present study. A meta-analysis was performed to qualitatively assess which process parameters (power, sonication time, essential oil, and tween 80 concentration) can influence the final droplet size and polydispersity and how droplet size is associated with antibacterial activity. We observed that power, essential oil, and tween 80 concentrations added during processing are the critical variables for forming smaller droplets. Ratios of up to 3:1 (surfactant:oil) can produce droplets smaller than 180 nm with antibacterial properties superior to pure oil or isolated compounds. The improved properties of nanoemulsions are associated with the size and chemical composition of the droplet since the proportion of the hydrophobic core (EO) and the hydrophilic outer layer (Tween 80) directly influences the antibacterial mechanism of action.

Comparative Phenotypic and Genomic Features of Staphylococci from Sonication Fluid of Orthopedic Implant-Associated Infections with Poor Outcome.

Staphylococcus spp. remain the leading biofilm-forming agents causing orthopedic implant-associated infections (OIAI). This is a descriptive study of phenotypic and genomic features identified in clinical isolates of S. aureus and coagulase-negative Staphylococcus (CoNS) recovered from OIAIs patients that progressed to treatment failure. Ten isolates were identified by matrix-time-of-flight laser-assisted desorption mass spectrometry (MALDI-TOF-MS) and tested for antibiotic susceptibility and biofilm formation. Genotypic characteristics, including, MLST (Multi Locus Sequence Typing), SCCmec typing, virulence and resistance genes were assessed by whole-genome sequencing (WGS). All S. aureus harbored mecA, blaZ, and multiple resistance genes for aminoglycosides and quinolones. All MRSA were strong biofilm producers harboring the complete icaADBC and icaR operon. Seven CoNS isolates comprising five species (S. epidermidis, S. haemolyticus, S. sciuri, S. capitis and S. lugdunensis) were analyzed, with mecA gene detected in five isolates. S. haemolitycus (isolate 95), and S. lugdunensis were unable to form biofilm and did not harbor the complete icaADBCR operon. High variability of adhesion genes was detected, with atl, ebp, icaADBC operon, and IS256 being the most common. In conclusion, MRSA and CoNS isolates carrying genes for biofilm production, and resistance to ß-lactam and aminoglycosides are associated with treatment failure in OIAIs.