Summary Bacterial meningitis continues to be an important cause of mortality and morbidity in neonates and children throughout the world. The introduction of the protein conjugate vaccines against ...Haemophilus influenzae type b, Streptococcus pneumoniae , and Neisseria meningitidis has changed the epidemiology of bacterial meningitis. Suspected bacterial meningitis is a medical emergency and needs empirical antimicrobial treatment without delay, but recognition of pathogens with increasing resistance to antimicrobial drugs is an important factor in the selection of empirical antimicrobial regimens. At present, strategies to prevent and treat bacterial meningitis are compromised by incomplete understanding of the pathogenesis. Further research on meningitis pathogenesis is thus needed. This Review summarises information on the epidemiology, pathogenesis, new diagnostic methods, empirical antimicrobial regimens, and adjunctive treatment of acute bacterial meningitis in infants and children.
Central nervous system (CNS) infections continue to be an important cause of morbidity and mortality. Microbial invasion and traversal of the blood-brain barrier is a prerequisite for CNS infections. ...Pathogens can cross the blood-brain barrier transcellularly, paracellularly and/or in infected phagocytes (the so-called Trojan-horse mechanism). Consequently, pathogens can cause blood-brain barrier dysfunction, including increased permeability, pleocytosis and encephalopathy. A more complete understanding of the microbial-host interactions that are involved in microbial traversal of the blood-brain barrier and the associated barrier dysfunction should help to develop new strategies to prevent CNS infections.
Outer membrane vesicles (OMVs) are important tools in bacterial virulence but their role in the pathogenesis of infections caused by enterohemorrhagic Escherichia coli (EHEC) O157, the leading cause ...of life-threatening hemolytic uremic syndrome, is poorly understood. Using proteomics, electron and confocal laser scanning microscopy, immunoblotting, and bioassays, we investigated OMVs secreted by EHEC O157 clinical isolates for virulence factors cargoes, interactions with pathogenetically relevant human cells, and mechanisms of cell injury. We demonstrate that O157 OMVs carry a cocktail of key virulence factors of EHEC O157 including Shiga toxin 2a (Stx2a), cytolethal distending toxin V (CdtV), EHEC hemolysin, and flagellin. The toxins are internalized by cells via dynamin-dependent endocytosis of OMVs and differentially separate from vesicles during intracellular trafficking. Stx2a and CdtV-B, the DNase-like CdtV subunit, separate from OMVs in early endosomes. Stx2a is trafficked, in association with its receptor globotriaosylceramide within detergent-resistant membranes, to the Golgi complex and the endoplasmic reticulum from where the catalytic Stx2a A1 fragment is translocated to the cytosol. CdtV-B is, after its retrograde transport to the endoplasmic reticulum, translocated to the nucleus to reach DNA. CdtV-A and CdtV-C subunits remain OMV-associated and are sorted with OMVs to lysosomes. EHEC hemolysin separates from OMVs in lysosomes and targets mitochondria. The OMV-delivered CdtV-B causes cellular DNA damage, which activates DNA damage responses leading to G2 cell cycle arrest. The arrested cells ultimately die of apoptosis induced by Stx2a and CdtV via caspase-9 activation. By demonstrating that naturally secreted EHEC O157 OMVs carry and deliver into cells a cocktail of biologically active virulence factors, thereby causing cell death, and by performing first comprehensive analysis of intracellular trafficking of OMVs and OMV-delivered virulence factors, we provide new insights into the pathogenesis of EHEC O157 infections. Our data have implications for considering O157 OMVs as vaccine candidates.
Due to global warming, the reducing air pollution is an important policy issue in the metropolitan area. Since the road mobile pollutant is the probable reason for the air quality pollution, the ...electric vehicle expansion is one of the main strategies for sustainable transportation systems. The expanded distribution of electric taxis depends on the important task of securing the investment feasibility compared to the currently operating liquefied petroleum gas (LPG) taxis. One thing to note is that a validity analysis is required to secure the sustainability of the switch from LPG to electric taxis and for the effective distribution of investment resources.
This study has diagnosed the implementation potential of electric taxis by analyzing the operating and charging behaviors of electric taxis from actual digital tachometer data which is consist of speed, driving distance, power usages of power train and by carrying out the feasibility study and environmental analysis for implementing electric taxis. It was found that the financial feasibility exists in converting private taxis to electric taxis, and the implementation potential is high. Moreover, the environmental analysis showed that socioeconomic benefits would be created with reduced air pollutants and CO2 from electric taxi operations.
As a result of feasibility study, the implementation of electric taxis is feasible from both financial and environmental perspectives under the current subsidy situations. Thus, attempts for sustainable urban transportation structure should be supported by operating behaviors, charging infrastructure, regulations, policies, and battery technology for the promotion of electric taxis.
The effects of microwave-integrated cold plasma (CP) treatments against spores of Bacillus cereus and Aspergillus brasiliensis and Escherichia coli O157:H7 on onion powder were investigated. The ...growth of B. cereus, A. brasiliensis, and E. coli O157:H7 in the treated onion powder was assessed during storage at 4 and 25 °C, along with the physicochemical and sensory properties of the powder. Onion powder inoculated with B. cereus was treated with CP using helium as a plasma-forming gas, with simultaneous exposure to low microwave density at 170 mW m−2 or high microwave density at 250 mW m−2. High microwave density-CP treatment (HMCPT) was more effective than low microwave density-CP treatment (LMCPT) in inhibiting B. cereus spores, but induced the changes in the volatile profile of powder. Increase in treatment time in HMCPT yielded greater inhibition of B. cereus spores. Vacuum drying led to greater inhibition of spores of B. cereus and A. brasiliensis than hot-air drying. HMCPT at 400 W for 40 min, determined as the optimum conditions for B. cereus spore inhibition, initially reduced the numbers of B. cereus, A. brasiliensis, and E. coli O157:H7 by 2.1 log spores/cm2, 1.6 log spores/cm2, and 1.9 CFU/cm2, respectively. The reduced number of B. cereus spores remained constant, while the number of A. brasiliensis spores in the treated powder increased gradually during storage at 4 and 25 °C and was not different from the number of spores in untreated samples by the end of storage at 4 °C. The E. coli counts in the treated powder fell below the level of detection after day 21 at both temperatures. HMCPT did not affect the color, antioxidant activity, or quercetin concentration of the powder during storage at both temperatures. The microwave-integrated CPTs showed potential for nonthermal decontamination of onion powder.
•Cold plasma treatment at high microwave power density (HMCPT) was investigated.•HMCPT improved the microbiological safety and storage stability of onion powder.•HMCPT inactivated microorganisms effectively on vacuum-dried onion powder.•HMCPT facilitates nonthermal decontamination of onion powder.•HMCPT did not affect antioxidant activity or quercetin content in onion powder.
► The As and F− co-contamination and their relationships in groundwater were studied. ► Sharing the same adsorbent, Fe (hydr)oxides, causes the co-contamination. ► Sulfate reduction is responsible ...for the weak correlation in reducing aquifers.
The co-contamination of arsenic (As) and fluoride (F−) in shallow aquifers is frequently observed worldwide, and the correlations between those contaminants are different according to the redox conditions. This study geochemically explores the reasons for the co-contamination and for the redox-dependent correlations by investigating the groundwater of an alluvial aquifer in Korea. Geochemical signatures of the groundwater in the study area show that the As concentrations are enriched by the reductive dissolution of Fe-(hydr)oxides, and the correlations between As and F− concentrations are poor comparatively to those observed in the oxidizing aquifers. However, F− concentrations are strongly dependent on pH. Desorption/adsorption experiments using raw soils and citrate–bicarbonate–dithionite treated soils indicated that Fe-(hydr)oxides are the important As and F− hosts causing the co-contamination phenomenon. The weaker correlation between F− and As in reducing aquifers is likely to be associated with sulfate reduction, which removes As from groundwater without changing the F− concentration.
Bumblebees are crucial for both natural ecosystems and agriculture, but their decline in distribution and abundance over the past decade is alarming. The global importance of bumblebees in natural ...ecosystems and agricultural food production cannot be overstated. However, the reported decline over the past decade has led to a surge of interest in understanding and addressing bumblebee population decline. Hence, we aimed to detect disruptions in the gut microbiome of male and worker bumblebees reared indoor and outdoor to assess potential resilience to environmental stress. Using the Illumina MiSeq platform for 16s rRNA amplicon sequencing, we analyzed the gut microbiome of male and worker bees that were raised indoors (designated as the IM and IW group) and those that were raised outdoors (also designated as the OM and OW group). Our results show presence of core bacteria Neisseriaceae, Orbaceae, Lactobacillaceae and Bifidobacteriaceae from indoor reared worker bees. However, a higher abundance of Bifidobacterium and absence of Fructobacillus from indoor reared worker bees was also observed. Indoor-reared male bees had lower diversity and fewer observed OTUs compared to outdoor-reared male bees. Additionally, the relative abundance of Actinobacteriota, Bacteroidota, and Firmicutes was significantly lower in indoor-reared males, while Proteobacteria was significantly increased. Despite this, we did not observe any dysbiosis in the gut microbiota of indoor-reared bumblebees when comparing the role of the gut symbionts among the groups. These results suggest that indoor-reared Bombus terrestris may be resilient to environmental stress when used as outdoor pollinators.
Background:
While the medial meniscal posterior horn (MMPH) is reported to bear a considerable portion of overall load on the knee joint, including compressive and shear forces, no study has yet ...investigated the relationship between the MMPH and posterior tibial slope (PTS), which is a geometric factor associated with the shear force component in the presence of a compressive load in the knee joint.
Hypothesis/Purpose:
The purpose was to investigate the relationship between the PTS and MMPH tears in patients without ligamentous injury. It was hypothesized that the PTS is greater in patients with MMPH tears as compared with those without.
Study Design:
Cohort study; Level of evidence, 3.
Methods:
From March 2015 to December 2018, 159 patients with isolated MMPH tears and 60 patients without any pathologic findings on magnetic resonance imaging (control group) were included in this study. The PTS in the affected and contralateral knees was compared between the groups, which were statistically matched according to baseline characteristics (ie, age, sex, body mass index, radiographic osteoarthritis grade according to the Kellgren-Lawrence scale, and hip-knee-ankle angle) via the inverse probability of treatment weighting method. Furthermore, the MMPH tear group was subdivided according to meniscal tear patterns; these subgroups were then compared with the control group.
Results:
The mean PTS was significantly greater in the MMPH tear group than in the control group (affected knee: MMPH tear group, 7.0°± 3.4° mean ± SD; control group, 5.2°± 2.1°, P < .001; contralateral knee: MMPH tear group, 6.7°± 3.3°; control group, 4.7°± 2.2°, P < .001). The mean PTS in each subgroup also tended to be greater than that in the control group. In the receiver operating characteristic curve analysis, the cutoff point of the PTS discriminating between the MMPH tear and control groups was 6.6° for the affected knee (sensitivity, 55.3%; specificity, 75.0%) and 5.5° for the contralateral knee (sensitivity, 61.0%; specificity, 76.7%).
Conclusion:
An increased PTS is strongly associated with an increased incidence of MMPH tears and less affected by the meniscal tear patterns.
Improvement of bone formation is necessary for successful treatment of the bone defects associated with osteoporosis. In this study, we sought to elucidate the osteogenic activity of peanut sprouts ...and their bioactive components. We found that peanut sprout water extract (PSWE) enhanced bone morphogenetic protein‐2‐mediated osteoblast differentiation in a dose‐dependent manner by stimulating expression of runt‐related transcription factor 2 (Runx2) via activation of AKT/MAP kinases. We identified a major component of PSWE, soyasaponin Bb, as the bioactive compound responsible for improvement of anabolic activity. Soyasaponin Bb from PSWE enhanced expression of the osteogenic transcription factor Runx2 and alkaline phosphatase. The soyasaponin Bb content depended on sprouting time of peanut, and the anabolic action of PSWE was dependent on soyasaponin Bb content. Thus, PSWE and soyasaponin Bb have the potential to protect against bone disorders, including osteoporosis.
The global decline in the population of wild bees has raised serious concerns, as bees are key pollinators that contribute to the sustainability of agriculture. Especially alarming, are the millions ...of managed bees in Korea that have recently disappeared. Although many abiotic and biotic stresses influence their physiology and behaviour, the causes of these declines have not been thoroughly elucidated. In recent studies, bee gut microbiota was found to play an important role in pathogen defence. We hypothesized that the gut microbiome of honeybees (Apis cerana) resistant (RH and RR) and susceptible (RL) to sacbrood virus disease may differ. To compare the gut bacterial communities of resistant and susceptible bees, alpha diversity and beta diversity analyses were performed. The analysis of alpha diversity revealed that RH had significantly higher Shannon diversity index values than RL. Beta diversity analysis showed that the gut bacterial community of RH was significantly different from that of RL. Four bacterial phyla were identified, and proteobacteria was the most abundant across all samples. Additionally, three operational taxonomic units (OTUs) belonging to Pasteurellales, Burkholderiales, and Pseudomonadales were identified only in RL. In conclusion, the gut bacterial community was significantly different between resistant and susceptible bees, and this difference may contribute to disease resistance.
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