Intraamniotic infection (defined as intraamniotic inflammation with microorganisms) is an important cause of the preterm labor syndrome. Methods for the detection of microorganisms in amniotic fluid are culture and/or polymerase chain reaction assay. However, both methods take time, and the results are rarely available for clinical decision-making. Nanopore sequencing technology offers real-time, long-read sequencing that can produce rapid results. To determine 1) the diagnostic performance of the 16S rDNA nanopore sequencing method for the identification of microorganisms in patients with intraamniotic inflammation and 2) the relationship between microbial burden and the intensity of the amniotic fluid inflammatory response. We performed a prospective cohort study that included singleton pregnancies presenting with symptoms of preterm labor with intact membranes or of preterm prelabor rupture of the membranes. Amniotic fluid samples were obtained for the evaluation of bacteria in the amniotic cavity using cultivation and polymerase chain reaction-based 16S Sanger sequencing methods. Participants were classified into 4 groups according to the results of an amniotic fluid culture, 16S Sanger sequencing, and an amniotic fluid interleukin 6 concentration: 1) no intraamniotic infection and intraamniotic inflammation (interleukin 6 <2.6 ng/mL, and no microorganisms in the amniotic cavity, as determined by culture or 16S Sanger sequencing); 2) microbial invasion of the amniotic cavity without intraamniotic inflammation, defined by the presence of bacteria detected by culture or 16S Sanger sequencing; 3) sterile intraamniotic inflammation (interleukin 6 ≥2.6 ng/mL without microbial invasion of the amniotic cavity); and 4) intraamniotic infection (interkeukin 6 ≥2.6 ng/mL with microbial invasion of the amniotic cavity). Patients who underwent a mid-trimester amniocentesis, had no intraamniotic infection or intraamniotic inflammation, and delivered at term represented the control group. 16S rDNA nanopore sequencing was performed and the diagnostic indices for the identification of intraamniotic infection were determined. Bioinformatic analysis was carried out to identify microorganisms, and a read count of at least 100 or a read count exceeding that of the background species from the control group, along with a relative abundance of no less than 1%, was used. 1) The 16S nanopore sequencing had a sensitivity of 88.9% (8/9), specificity of 95.4% (41/43), positive predictive value of 80.0% (8/10), negative predictive value of 97.6% (41/42), positive likelihood ratio of 19.1 (95% confidence interval, 4.8-75.4), negative likelihood ratio of 0.1 (95% confidence interval, 0.02-0.7), and an accuracy of 94.2% (49/52) for the identification of intraamniotic infection (prevalence, 17% [9/52]); 2) the microbial load determined by the 16S nanopore sequencing had a strong positive correlation with the intensity of an intraamniotic inflammatory response (amniotic fluid interleukin 6 concentration; Spearman's correlation 0.9; P=.002); and 3) a subgroup of patients with intraamniotic inflammation did not have bacteria determined by culture, Sanger sequencing, or nanopore 16S, thus confirming the existence of sterile intraamniotic inflammation. The 16S nanopore sequencing has high diagnostic indices, predictive values, likelihood ratios, and accuracy in the diagnosis of intraamniotic infection.
The National Healthcare Safety Network (NHSN) of the Centers for Disease Control and Prevention (CDC) needed a modernized approach to manage resources containing standardized terminology that specify microorganism data submitted electronically for legacy reporting. Health care-associated infections (HAIs) reported to NHSN require the submission of data regarding specific microorganisms attributed to the patient's condition. Data on microorganisms submitted to the NHSN electronically must use the SNOMED CT terminology standard. Terminology artifacts that guide submission of microorganism data have been maintained in spreadsheets that have become increasingly challenging to manage. This case report details the initial use case for the implementation of off-the-shelf software within the NHSN to modernize the maintenance of terminology assets. Resources that guide reporting microorganisms for HAIs were used as a prototype to demonstrate how a software application can be practically implemented to streamline the maintenance of complex terminology assets. Mission-critical artifacts have been reconciled and consolidated into a single source of truth knowledgebase using an off-the-shelf software solution. This report shares progress and lessons learned regarding the modernization of NHSN's Pathogen Codes resource and its derivative artifacts. A model is now available that can be replicated across other NHSN legacy artifacts. Our experience can be applied to other public health use cases and information systems facing similar challenges with attachments to legacy terminology resources and systems.
Microorganisms isolated from clinical samples in hospitalized patients vary in species and antibiotic sensitivity, depending on whether they are community or healthcare-associated infections. In a hospital in the Buenos Aires Metropolitan Area, bacterial isolates and their antibiotic resistance were related to the length of hospitalization, as a guide to adjust antibiotic therapy. Microbiological isolates, antibiogram results, and antibiotic treatment of hospitalized patients were recorded weekly between 1/1/2022 and 12/31/2023. Four groups were assigned according to time since hospitalization: G1 (<3 days), G2 (3-7 days), G3 (7-14 days), and G4 (≥14 days). In the first week of hospitalization, the main microorganism isolated, from community-acquired infection, was Escherichia coli (132 isolates), with high levels of resistance to quinolones, followed by Klebsiella pneumoniae (82 isolates) and Staphylococcus aureus (64 isolates). Between 11/10/23 and 8/12/23, an outbreak of K. pneumoniae carbapenemase MBL was detected in biliodigestive and urological surgery, and it was controlled. Of the antibiotics used: ciprofloxacin went from second in use in G1 and first in G2, to third and fifth in G4. Indications for amoxicillin/sulbactam decreased from G3. Carbapenems and colistin increased from G3. Piperacillin/tazobactam and vancomycin were widely used in all periods. This simple weekly control allowed us to know the microbiology in the hospital, its antibiotic sensitivity patterns, detect outbreaks, and adjust the rational use of antibiotics, especially empirical, notably in the abuse of ciprofloxacin in urinary or abdominal foci; and compare the isolations and therapeutic behaviors with national and international patterns. Introducción: Los microorganismos aislados de muestras clínicas, en pacientes internados, varían en especies y sensibilidad antibiótica, según sean de origen comunitario o nosocomial. En un hospital del Conurbano Bonaerense, se relacionaron los aislamientos bacterianos, y su resistencia antibiótica, con la duración de la internación, como guía para ajustar la antibioticoterapia. Materiales y métodos: Se registraron semanalmente los aislamientos microbiológicos, resultados de antibiograma y tratamiento antibiótico de pacientes internados, entre 1/1/2022 y 31/12/2023. Se asignaron cuatro grupos según tiempo desde internación: G1 (<3 días), G2 (3-7 días), G3 (7-14 días) y G4 (≥14 días). Resultados: En la primera semana de internación el principal microorganismo aislado, de origen comunitario, fue Escherichia coli (132 aislamientos), con altos niveles de resistencia a quinolonas, seguido por Klebsiella pneumoniae (82 aislamientos) y Staphylococcus aureus (64 aislamientos). Entre 11/10/23 y 8/12/23 se detectóun brote de K. pneumoniae carbapenemasa MBL en cirugía biliodigestiva y urológica, y fue controlado. De los antibióticos empleados: ciprofloxacina pasóde segunda en uso en G1 y primera en G2, a tercera y quinta en G4. Las indicaciones de amoxicilina/sulbactam disminuyeron desde G3. Carbapenemes y colistina aumentaron desde G3. Piperacilina/tazobactama y vancomicina fueron muy utilizadas en todos los períodos. Este sencillo control semanal permitióconocer la microbiología del hospital, sus patrones de sensibilidad antibiótica, detectar brotes, y ajustar el uso racional de antibióticos, especialmente el empírico (notablemente en el abuso de ciprofloxacina en focos urinarios o abdominales); y comparar los aislamientos y las conductas terapéuticas con patrones nacionales e internacionales.
Soil microorganisms play a crucial role as a link between vegetation and soil nutrient cycling. However, it is unclear how vegetation and soil influence microbial community during the ecological restoration process of the Mu Us Desert. Using phospholipid fatty acid (PLFA) markers and integrating shrub, herbaceous plants, and soil factors, we explored the characteristics and regulations of soil microbial community changes. In this study, we used and took the soil after 10, 30, 50, and 70 years of Caragana korshinskii sand-fixing forest restoration, with moving dunes as a control (0 year). The results showed that the ecological restoration effect index increased significantly with the increase of recovery years. The total PLFA contents in 0, 10, 30, 50, and 70 years were 47.75, 55.89, 63.53, 67.23, and 82.29 nmol·g-1, respectively. With the increases of ecological restoration index, the biomass of fungi and bacteria, as well as the ratio of Gram-positive to Gram-negative bacteria, all showed significant increase, while the biomass of Gram-positive and Gram-negative bacterial communities, and the ratio of fungi to bacteria, demonstrated significant decrease. Shrub, herbaceous plants, and soil factors could explain 72.4% of the vari-ation of soil microbial community composition, with higher contribution of soil factors than vegetation factors. The total content of phospholipid fatty acids of soil microbial community in Mu Us Desert increased with the increases of restoration years. Soil water content, pH, total nitrogen, and soil organic carbon were the main driving factors affecting the characteristics of soil microbial community. With the increases of restoration years of C. korshinskii sand-fixation forests in the Mu Us Desert, there were significant changes in the structure of soil microbial communities, which were primarily driven by soil factors. 土壤微生物是连接地上植被和土壤养分循环的关键枢纽,然而对于毛乌素沙地生态恢复过程中植被和土壤对微生物群落的影响还不明确。本研究以流动沙丘为对照(0年),以10、30、50和70年的柠条固沙林土壤为研究对象,将磷脂脂肪酸(PLFA)标记法与灌木、草本植物和土壤因子结合,探究不同恢复年限下土壤微生物群落特征的变化规律及其调控因子。结果表明: 随着恢复年限的增加,生态恢复效应指数显著增加。0、10、30、50和70年的总PLFA含量分别为47.75、55.89、63.53、67.23和82.29 nmol·g-1。随着生态恢复指数增加,细菌含量和革兰氏阳性菌与革兰氏阴性菌比均显著增加;革兰氏阴性菌群落含量和真菌与细菌比均显著下降。灌木、草本植物和土壤因子能解释土壤微生物群落72.4%的变异,其中土壤因子的贡献高于植被因子。毛乌素沙地土壤微生物群落的总PLFA含量随恢复年限的增加而增加,并且土壤含水量、酸碱度、全氮和土壤有机碳为影响土壤微生物群落特征的主要驱动因子。随着毛乌素沙地柠条固沙林恢复年限的增加,主要由土壤因子驱动的土壤微生物群落结构发生显著变化。.
Consumer products such as detergents, fabric softeners, and cosmetics are typically used in various environments. Manufacturers must ensure the quality of products and ensure their safety through their lifecycle, from manufacturing to usage. Preservation efficacy testing (PET) is typically conducted to determine the preservative of a product prior to use. However, PET is time-consuming and laborious due to its long-term storage and culture-based detection methods. In this study, we focused on the metabolic activities of microorganisms and developed a rapid alternative to PET. We observed that 72 h of preservation was sufficient to predict preservation efficacy using the metabolic activity method. Finally, the accuracy of the metabolic activity method was compared to that of PET using a variety of products such as detergents and cosmetics. The accuracy of this alternative method exceeds 85% for highly fluid and easy-to-handle samples. These results suggest that the developed metabolic activity method possesses the potential to determine the preservative efficacy of products in only four days（72 h of preservation and 24 h of detection）. Thus, this method possesses the potential to provide a rapid and simple alternative to PET.
An air washer-type humidifier has two useful functions: humidification, and air purification, and it applies to large indoor spaces. In this study, the efficacy of an air washer-type humidifier fed with 24 L of weakly acidic electrolyzed water（WAEW) at pH 5.0 and 30 mg/L in disinfecting attached bacteria and airborne microorganisms was studied in a 480 m3 indoor space. The humidifier was operated at a shower volume of 9.0 L/min of WAEW and at an air flow rate of 29 m3/min. Volatilization of gaseous hypochlorous acid（HOCl(g)) proceeded according to first-order kinetics during the 60 min of operation. Fresh WAEW was supplied to the humidifier every 60 min, and the HOCl(g) concentration in the indoor space was maintained within the range of 25-52 ppb for at least 180 min of operation. The number of viable bacterial cells on wet agar plates placed on the floor at a distance of 5-20 m away from the humidifier decreased by 2.0-3.0 log after 30 min of operation, and no viable cells were detected after 60 min of operation. A logarithmic reduction of more than 2.7 was achieved within 15 min against bacteria-attached plates placed at a 1.5 m-height position where the outlet airflow from the humidifier was directly exposed. This indicates that the disinfection efficacy of HOCl(g) volatilized from the humidifier depends on the rate of outlet airflow reaching the bacteria-attached plates. The number of viable airborne microorganisms decreased by approximately 54% after 180 min of operation. This study demonstrated that an air-washer-type humidifier can spread HOCl(g) evenly throughout a large indoor space and is effective in disinfecting attached bacteria and airborne microorganisms.
Properly validated procedures can reduce variation and lead to data that is more accurate and precise. Analytical procedure lifecycle management (APLM) is a statistical approach based on uncertainty measurements that validates procedures by demonstrating they are fit for purpose. APLM results can also be used to compare procedures. This paper builds upon previous publications that introduced, developed, and demonstrated the application of APLM as described in USP <1220> to a microbiological analytical procedure. The application of APLM is demonstrated in two MS EXCEL workbooks that are provided: Template APLM, that can be used to apply APLM to any microbiological plate count procedure and Case Study APLM detailing the APLM validation and comparison of enumeration procedures associated with a Lactobacillus acidophilus probiotic ingredient. The measurand and analytical target profile are clearly defined, a risk assessment is documented, and an analytical control strategy created. Two different procedures, ISO 20128 and USP <64>, are compared using tolerance intervals (TI) calculated from the procedures' uncertainties. Tools to ease validation and comparison and all required statistical equations are contained within the workbooks. Case study data, which is based on a Lactobacillus acidophilus, single-strain, powdered ingredient, was generated in a manufacturing facility laboratory. This example of using APLM validated ISO 20128 as fit for the purpose of enumerating L. acidophilus in a powdered probiotic ingredient by showing that the intermediate precision (0.062 log10 CFU/g) was less than the target measurement uncertainty (0.097 log10 CFU/g). When comparing ISO 20128 to USP <64> overlapping tolerance intervals were observed; 11.14-11.76 log10 CFU/g and 11.41 to 11.62 log10 CFU/g, respectively. The results indicate the procedures are similar, but not equivalent. Options for using APLM and TI information are discussed. This study shows that APLM and tolerance intervals are useful tools that improve and ease procedure selection, assist in information gathering that leads to better understanding and control of analytical procedures, and helps improve data quality.
In 2019, a worldwide pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged. SARS-CoV-2 is the deadly microorganism responsible for coronavirus disease 2019 (COVID-19), which has caused millions of deaths and irreversible health problems worldwide. To restrict the spread of SARS-CoV-2, accurate detection of COVID-19 is essential for the identification and control of infected cases. Although recent detection technologies such as the real-time polymerase chain reaction delivers an accurate diagnosis of SARS-CoV-2, they require a long processing duration, expensive equipment, and highly skilled personnel. Therefore, a rapid diagnosis with accurate results is indispensable to offer effective disease suppression. Nanotechnology is the backbone of current science and technology developments including nanoparticles (NPs) that can biomimic the corona and develop deep interaction with its proteins because of their identical structures on the nanoscale. Various NPs have been extensively applied in numerous medical applications, including implants, biosensors, drug delivery, and bioimaging. Among them, point-of-care biosensors mediated with gold nanoparticles (GNPSs) have received great attention due to their accurate sensing characteristics, which are widely used in the detection of amino acids, enzymes, DNA, and RNA in samples. GNPS have reconstructed the biomedical application of biosensors because of its outstanding physicochemical characteristics. This review provides an overview of emerging trends in GNP-mediated point-of-care biosensor strategies for diagnosing various mutated forms of human coronaviruses that incorporate different transducers and biomarkers. The review also specifically highlights trends in gold nanobiosensors for coronavirus detection, ranging from the initial COVID-19 outbreak to its subsequent evolution into a pandemic.
For the treatment of candidemia, especially in critical care settings, rapid identification of Candida species remains essential. Hybrid compounds have emerged as a powerful strategy to address challenges in microbiological detection and control. By integrating organic and inorganic components within a single architecture, these materials exhibit synergistic physicochemical and biological properties that are useful for sensor platform strategies. Lectins can act as bioreceptors due to their affinity for carbohydrates, and the addition of nanomaterials increases the platform's surface area and sensitivity. This work developed an electrochemical biosensor using a self-assembling monolayer of 4-mercaptobenzoic acid (MBA) and a hybrid nanocomposite composed of chitosan-coated magnetite nanoparticles capped with gold (Fe3O4@Chit@Au) and the lectin Concanavalin A (ConA) as the biorecognition element. The hybrid architecture was designed to enhance the microorganism-sensor interface by increasing surface area and improving lectin immobilization. Topographic analysis confirmed the effective assembly of the sensing layer on gold electrodes. Selective responses to Candida albicans and Candida tropicalis were observed by electrochemical analysis, whereas bacterial species such as Staphylococcus aureus, Klebsiella pneumoniae, and Bacillus subtilis exhibited reduced signals. The stronger response for Candida species is consistent with the high affinity of ConA for mannan residues present in fungal cell walls. The biosensor demonstrated a limit of detection of 0.71 CFU.mL⁻1 and a limit of quantification of 2.39 CFU.mL⁻1 for C. albicans within a working range of 101-105 CFU.mL⁻1. These findings demonstrate how lectin-based electrochemical platforms can identify and distinguish clinically significant microorganisms.
This study aimed to compare and assess residual microorganisms and organic materials on selected dental instruments after practicing two infection control methods, including the standard protocol. Scaler tips (ST) , 3-way syringe tips（3ST) , Bristle brushes（BB) , and Rubber cups（RC) were collected and grouped into Standard (Group S) and Non-standard (Group N) for processing. In ST and 3ST, Group S was cleaned and autoclaved, while Group N was disinfected. For BBs and RCs, Group N was cleaned and autoclaved, and new instruments were used as Group S. To confirm the presence of residual microorganisms, instruments from each group were incubated in liquid and solid medium. The generated colonies on solid medium were identified at the species level by polymerase chain reaction (PCR) . To confirm the presence of residual organisms, each instrument was stained with Phloxine B and observed using a stereomicroscope. Only ST（8.0%) and 3ST (28.0%) samples from Group N were detected with residual microorganisms. The identified colonies included Staphylococcus, Cupriavidus, and Streptococcus spp. Residual organics were observed in all samples from Group S and N. These findings highlight the limitations of cleaning followed by autoclaving and especially disinfection in completely eradicating all microorganisms and organics.
Otitis externa is an ear disease that is present in 10-20% of dogs. Bacterial organisms are a common cause, and infection may cause severe and chronic inflammation. Thus, there is a need for early detection and identification of bacteria in ear discharge samples. In this study, 31 such samples were analyzed to identify microorganisms using MALDI-TOF MS with pretreatment using a membrane filtration protocol and a rapid BACpro II kit, compared to pretreatment with a rapid BACpro II kit alone. Reliable scores for E. coli and E. faecalis were obtained after inoculation of samples with 1.0×104 CFU/ml using the membrane filter with the rapid BACpro II kit, with approximately 10-fold higher sensitivity compared to rapid BACpro pretreatment alone. Among 31 bacteria-positive colonies in the samples, MALDI-TOF MS and membrane filtration (0.80 µm) with a rapid BACpro II kit was significantly more accurate compared to use of the kit alone (29 (82.9%) vs. 17 (48.6%) isolates identified, p<0.001). These results show that MALDI-TOF MS with a membrane filter and a rapid BACpro II kit is a quick and reliable method for bacterial identification in ear discharge samples.
Oleaginous microorganisms can produce polyunsaturated fatty acids beneficial to human health through adjusting the nitrogen content in the medium. The target of rapamycin complex 1 (TORC1) is important for nitrogen sensing and then regulates lipid metabolism. However, the function of Kog1, a subunit of TORC1, in TORC1-regulated lipid metabolism in oleaginous microorganisms remains unclear. In this study, the gene kog1 was knocked out to explore the mechanism of lipid accumulation in the oleaginous fungus M. circinelloides under nitrogen-limited and nitrogen-rich conditions. The results showed that the cell dry weight (CDW) of the kog1 deletion mutant was obviously decreased from 22.2 to 15.4 g/L under nitrogen-limited conditions; however, the lipid content markedly increased by 43.2% compared to the control, from 20.8% of CDW to 29.9%. A similar trend was observed under nitrogen-rich conditions; the cell growth was significantly inhibited, the CDW was decreased from 28.6 to 23.0 g/L, and the lipid content increased by 79.6% compared to the control strain, reaching 9.7% of CDW. The addition of rapamycin further enhanced lipid accumulation in the kog1 knockout mutant but not in the tor knockout mutant, indicating that Kog1 is the upstream target of rapamycin (TOR) in regulating lipid regulation. Transcriptional analysis under both nitrogen-limited and nitrogen-rich conditions notably suggested that nitrogen stress may activate Snf1/AMPK to inhibit Kog1, facilitating SREBP-1c nuclear translocation and activating fatty acid biosynthesis genes.
The commercial products of calcium hypochlorite (Ca（OCl) 2) , a solid hypochlorite salt, are hygroscopic because of the presence of calcium chloride as an impurity. In this study, we investigated the volatilization of gaseous hypochlorous acid (HOCl (g) ) from Ca (OCl) 2 tablets and its disinfection efficacy against Staphylococcus aureus on wet agar plates were studied in a 75 m3 room. HOCl (g) volatilization occurred spontaneously and continuously, even in ambient air. Under airflow conditions, the absorption of water vapor from the air into the Ca (OCl) 2 tablet was accelerated, and numerous droplets were formed on the tablet surface. The deliquescent property of calcium chloride indices these phenomena. When a glass Petri dish containing 10 Ca (OCl) 2 tablets was placed in the room under airflow conditions, HOCl (g) volatilization of was enhanced, and the HOCl (g) concentration in the room was maintained within the range of 60‒80 ppb for at least 24 h of volatilization. Viable S. aureus count on wet agar plates placed on the floor 1‒5 m away from the tablets decreased by 3.1-log after 1.5 h of exposure. This study indicates that sufficient concentrations of HOCl (g) can be volatilized from Ca (OCl) 2 tablets without the use of water, contributing to the disinfection of attached bacteria.
Traditional detection of foodborne pathogen relies on advanced analyzers, which is inadequate for the rapid control of infections, particularly in resource-limited regions, highlighting the necessity of developing detection systems for point-of-care testing (POCT). Herein, taking Vibrio parahaemolyticus as a detecting target, we reported poly-L-lysine functionalized silica membrane (PL-SM) based loop-mediated isothermal amplification (pLAMP) platform for sensitive on-site detection. This platform utilized PL-SM for DNA capture driven by the electrostatic attraction between protonated amine groups of poly-L-lysine and negatively charged phosphate groups of DNA, followed by introducing a colorimetric indicator calcein for LAMP amplification. After optimization, the colorimetric mode of pLAMP allowed the screening of V. parahaemolyticus with the visual limit of detection (vLOD) of 1 CFU/mL in 50 min, 1000-fold lower than methods based on commercial kits. Validation was performed using 174 seafoods, which was 97 % concordant to those of real-time PCR. Furthermore, an image processing approach was developed based on the analysis of the RGB under UV light. Paired with a smartphone, the objective analytical method could be readily conducted in the field. Thus, we propose a sensitive and visual detection platform, which may play a crucial role in improving testing efficiency and accuracy in food safety, medical diagnostics, and environmental monitoring.
The high permeability of silicone rubber is beneficial for use in membranes for pervaporation. In this study, pervaporation of hypochlorous acid (HOCl) was studied using a separation module containing a 6,000 silicone rubber (SR) hollow fiber membrane. Pervaporation experiments were conducted in a 1 m3 chamber. The membrane module was operated without using a vacuum pump, and the permeation of HOCl proceeded according to the solution-diffusion process. When weakly acidic (pH 5.0) hypochlorite solutions with concentrations of 100-1,000 mg/L were fed through the lumen of the SR hollow fiber membrane, the permeation of HOCl proceeded spontaneously under atmospheric pressure. During the operation of the membrane module, the concentration of gaseous hypochlorous acid (HOCl(g)) in the chamber gradually increased and reached a steady state. The steady-state HOCl(g) concentration increased as the concentration of undissociated hypochlorous acids (HOCl(aq)) in the feed hypochlorite solutions increased. An exponential dependence of the steady-state HOCl(g) concentration on the steady-state HOCl(aq) concentration was observed. Operation of the SR hollow fiber membrane fed with weakly acidic hypochlorite solutions (i.e., 500 mg/L) in a 75 m3 room resulted in a uniform distribution of 7-10 ppb HOCl(g), thereby exerting a moderate bactericidal effect against Staphylococcus aureus cells.
Establishing a technique that can inactivate highly heat-resistant bacterial spores under milder conditions would be of great benefit in terms of ensuring food safety and extending shelf life. In this study, we investigated the combined effect of hydrostatic pressure processing (HPP) and the addition of a food emulsifier (sucrose fatty acid ester; SE) on two bacterial spores (Bacillus spizizeni and Alicyclobacillus acidoterrestris）. The results demonstrated that supplementing HPP at 50 MPa with SE significantly reduced the heat resistance of both spores. In particular, A. acidoterrestris spores were more sensitive to treatment than the B. spizizenii spores. HPP combined with SE resulted in a 4 log reduction in A. acidoterrestris spores, whereas a 2 log reduction was observed for B. spizizenii spores. Additionally, heat treatment following HPP combined with SE further inactivated B. spizizenii spores by 0.5 log. To evaluate practical applications in the food industry, the effect of the SE-HPP combination in the presence of glucose, a representative nutrient component, was also assessed. The findings indicated that the heat resistance of A. acidoterrestris spores was reduced, with viable spore counts falling below the detection limit (less than 10 CFU/mL）. These results suggest that this approach may enhance the efficiency of HPP in bacterial spore control for food processing applications.
This review explores the fundamental mechanisms behind sporulation, germination, and outgrowth of spore-forming bacteria, with a focus on how environmental conditions affect these processes. By detailing factors such as temperature, pH, and water activity, it examines how these elements influence transitions between vegetative growth, sporulation, and germination, as well as the quality of the spores produced, particularly their resistance and germination ability. The review also addresses the heterogeneity observed in the spore-forming bacteria life cycle, particularly variation in germination and outgrowth responses, as well as phenomena such as cannibalism, competence, and biofilm formation. It highlights the significance of these factors for understanding the persistence and dispersal of spores across different environments. The implications of these mechanisms are particularly relevant for the food industry, where effective management of contamination by spores is critical for controlling food spoilage and safety. It also has important implications for biotechnology. A better understanding of how environmental conditions influence spore properties can help optimize the production of spores with specific resistance or germination traits suited to their intended applications.
Aquaculture disease management, historically reliant on antibiotics and synthetic chemicals, requires sustainable and effective alternatives for microbial control. One of the strategies is by utilizing bioactive compound from natural product. However, the current method of extraction requires a huge amount of solvent and cause detrimental to the end product. Thus, this lead to extraction strategy using supercritical carbon dioxide (SC-CO2). This minireview explores the application of SC-CO2 extraction as a green technology for disease management in aquaculture. SC-CO2 operates as a clean, selective solvent, efficiently isolating high-purity bioactive compounds from plant, algal, and fishery by-products without toxic solvent residues. Unlike conventional extraction methods, SC-CO2 preserves thermolabile antimicrobial compounds, yielding extracts with enhanced bioactivity against aquatic pathogens. By providing effective, natural alternatives to antibiotics, SC-CO2 technology directly contributes to disease control in aquaculture. The integration of SC-CO2-derived natural products represents a transformative strategy for sustainable microbial control while aligning with the principles of environmental safety and food security.
When a hypochlorite solution is ultrasonically fogged in a room, free chlorine, i.e., HOCl and OCl-, reaches various positions in two forms: fine fog droplets and gaseous hypochlorous acid（HOCl(g)）. In this study, the cumulative amount of free chlorine reaching various positions on the floor away from the fogger was measured in a 90-m3 room, using a sulfamate-carrying glass-fiber filter indicator. The fine droplets were blown out from the fogger into the spaces at different discharge port angles of 30 - 90°. Free chlorine was successfully trapped by sulfamate, forming monochlorosulfamate, which was stably retained on the indicator. The cumulative amount of free chlorine（ ng/indicator） increased with fogging time at each position and depended on the blow angle and distance from the fogger. Minor differences in the HOCl(g) concentration near the floor at all positions were observed. The disinfection efficacy of the fogging treatment against Staphylococcus aureus on wet surfaces was relatively higher at positions near the fogger and lower at positions far from the fogger. At each discharge port angle, a strong correlation between the logarithmic reduction in relative viable cells and the cumulative amount of free chlorine reaching S. aureus plates was observed. The slopes of the regression lines of correlation diagrams as a function of the cumulative amount of free chlorine were between -0.0362 and -0.0413 ng-1. This study demonstrated that the cumulative amount of free chlorine measured using the filter indicator could reflect the sum of the free chlorine of both fine droplets and HOCl(g), and that the disinfection efficiency depended on the cumulative amount of free chlorine reaching different areas.
Street and park trees often endure harsher conditions, including increased temperatures and drier soil and air, than those found in urban or natural forests. These conditions can lead to shorter lifespans and a greater vulnerability to dieback. This literature review aimed to identify confirmed causes of street and park tree dieback in urban areas from around the world. Peer-reviewed case studies related to urban tree decline were scanned for the words "urban", "city", "cities", "tree*", "decline", "dieback", "mortality", and "survival". From an initial pool of 1281 papers on Web of Science and 1489 on Scopus, 65 original peer-reviewed research papers were selected for detailed analysis. Out of all species reported to decline, 46 were native, while non-natives were represented by 35 species. The most commonly affected trees were Platanus, Fraxinus, Acer, and Ficus. Most studies were conducted in Mediterranean, humid subtropical, and humid continental climates, with the greatest representation from the United States, followed by Australia, Brazil, Iran, Italy, and Russia. Many authors focused on either biotic or abiotic causes of dieback; some explored both, and some also discussed underlying environmental and urban stresses as potential predisposing factors. The majority (81% of the papers) concluded that a decline was caused by either an arthropod or a microorganism. Overall, it was suggested that changing management strategies to improve water availability and soil health might help with tree resilience. Additionally, regular monitoring and research, along with improving tree species selection and implementing biological and chemical control methods, can help prevent or slow down tree decline. Increasing awareness and adopting preventative approaches could help to extend the lifespan of street and park trees in urban environments and mitigate some of the biological threats, especially considering the challenges we may be facing due to the changing climate.