Sepsis: mechanisms of bacterial injury to the patient

Bacterial heat shock protein: A new crosstalk between T lymphocyte and macrophage via JAK2/STAT1 pathway in bloodstream infection

Bloodstream infection (BSI) refers to the infection of blood by pathogens. Severe immune response to BSI can lead to sepsis, a systemic infection leading to multiple organ dysfunction, coupled with drug resistance, mortality, and limited clinical treatment options. This work aims to further investigate the new interplay between bacterial exocrine regulatory protein and host immune cells in the context of highly drug-resistant malignant BSI. Whether interfering with related regulatory signaling pathways can reverse the inflammatory disorder of immune cells. In-depth analysis of single-cell sequencing results in Septic patients for potential immunodeficiency factors. Analysis of key proteins enriched by host cells and key pathways using proteomics. Cell models and animal models validate the pathological effects of DnaK on T cells, MAITs, macrophages, and osteoclasts. The blood of patients was analyzed for the immunosuppression of T cells and MAITs. We identified that S. maltophilia-DnaK was enriched in immunodeficient T cells. The activation of the JAK2/STAT1 axis initiated the exhaustion of T cells. Septic patients with Gram-negative bacterial infections exhibited deficiencies in MAITs, which correspond to IFN-γ. Cellular and animal experiments confirmed that DnaK could facilitate MAIT depletion and M1 polarization of macrophages. Additionally, Fludarabine mitigated M1 polarization of blood, liver, and spleen in mice. Interestingly, DnaK also repressed osteoclastogenesis of macrophages stimulated by RANKL. S.maltophilia-DnaK prompts the activation of the JAK2/STAT1 axis in T cells and the M1 polarization of macrophages. Targeting the DnaK's crosstalk can be a potentially effective approach for treating the inflammatory disorder in the broad-spectrum drug-resistant BSI.

Comparative Evaluation of Different Tissues and Molecular Techniques for the Zoonotic Surveillance of Scrub Typhus

Background and Objectives: Scrub typhus (ST) is detected in one-fourth of patients with acute febrile illnesses, confirming its nationwide re-emergence. The disease, if not diagnosed, can lead to multiple organ dysfunction and mortality. Being a vector-borne zoonotic disease, the molecular survey for pathogens in animal hosts is essential to predict the risk of its transmission to humans. Hence, this study aimed at identifying the effective animal tissue and molecular technique for zoonotic surveillance of ST infection in small animal hosts. Methods: Rodents/shrews were trapped from seventeen randomly selected villages in Puducherry between July and September, 2022. The presence of Orientia tsutsugamushi in ectoparasites and tissues including blood, lung, liver, spleen, kidney, heart, brain, and intestine retrieved from the animals was screened by nested PCR targeting 56 kDa, real-time PCR (qPCR) targeting 47 kDa and traD, and conventional PCR targeting groEL. The Weil-Felix test was carried out to detect antibodies against O. tsutsugamushi in rodent/shrew serum samples. Diagnostic accuracy measures of the molecular tests were calculated for each of the tissues by latent class modeling. Results: O. tsutsugamushi detected in the rodents/shrews were identified to be Karp-like and Kawasaki-like strains. Upon statistical analysis, qPCR targeting 47 kDa exhibited the highest accuracy measures in most of the tissues analyzed, with perfect sensitivity and specificity of 100% and 97% for intestine and lung samples for the epidemiological surveillance, respectively. Interpretation and Conclusion: The study recommends qPCR targeting 47 kDa gene and analysis of intestine and lung along with blood for the zoonotic surveillance of ST infection.

The Role of TRP Channels in Sepsis and Colitis

To date, several members of the transient receptor potential (TRP) channels which provide a wide array of roles have been found in the gastrointestinal tract (GI). The goal of earlier research was to comprehend the intricate signaling cascades that contribute to TRP channel activation as well as how these receptors' activity affects other systems. Moreover, there is a large volume of published studies describing the role of TRP channels in a number of pathological disorders, including inflammatory bowel disease (IBD) and sepsis. Nevertheless, the generalizability of these results is subject to certain limitations. For instance, the study of IBD relies on various animal models and experimental methods, which are unable to precisely imitate the multifactorial chronic disease. The diverse pathophysiological mechanisms and unique susceptibility of animals may account for the inconsistency of the experimental data collected. The main purpose of this study was to conduct a comprehensive review and analysis of existing studies on transient receptor potential (TRP) channels implicating specific models of colitis and sepsis, with particular emphasis on their involvement in pathological disorders such as IBD and sepsis. Furthermore, the text endeavors to evaluate the generalizability of experimental findings, taking into consideration the limitations posed by animal models and experimental methodologies. Finally, we also provide an updated schematic of the most important and possible molecular signaling pathways associated with TRP channels in IBD and sepsis.

Therapeutic bacteria and viruses to combat cancer: double-edged sword in cancer therapy: new insights for future

Cancer, ranked as the second leading cause of mortality worldwide, leads to the death of approximately seven million people annually, establishing itself as one of the most significant health challenges globally. The discovery and identification of new anti-cancer drugs that kill or inactivate cancer cells without harming normal and healthy cells and reduce adverse effects on the immune system is a potential challenge in medicine and a fundamental goal in Many studies. Therapeutic bacteria and viruses have become a dual-faceted instrument in cancer therapy. They provide a promising avenue for cancer treatment, but at the same time, they also create significant obstacles and complications that contribute to cancer growth and development. This review article explores the role of bacteria and viruses in cancer treatment, examining their potential benefits and drawbacks. By amalgamating established knowledge and perspectives, this review offers an in-depth examination of the present research landscape within this domain and identifies avenues for future investigation.

Unraveling the immune response of the spleen in sepsis using green-synthesized silver nanoparticles from pomegranate peel extracts

Sepsis is a serious disease characterized by an inappropriate host response to infection, resulting in widespread inflammation and systemic organ failure. The aim of this research is to investigate the possibility of pomegranate peel-derived silver nanoparticles (PGNP) as a potential alternative therapy for sepsis. Characterization using transmission electron microscopy revealed 10-30 nm spherical nanoparticles. In a rat model of sepsis, PGNP treatment improved spleen health, histology, and immune response as compared with septic rats. In rats treated with PGNP during sepsis, significant alterations in oxidative stress markers (p < .01) were observed. These included elevated levels of glutathione (0.63 ± 0.08 mmol/mg protein), reduced concentrations of nitric oxide (8.7 ± 0.8 μ mol/mg protein) and malondialdehyde (2.2 ± 0.3 nmol/mg protein), as well as increased activity of superoxide dismutase (159 ± 33 U/mg protein). Following PGNP administration, gene expression analysis revealed a decrease in spleen IL-1β, IL-6, and TNF-α, highlighting its anti-inflammatory potential. Furthermore, PGNP effectively controlled apoptosis-related genes (Bax, Bcl-2, and Casp3), indicating its role in cellular survival pathways. This study sheds light on the immunological regulation of the spleen during sepsis using PGNP, demonstrating its potential as a new effective treatment approach. The study emphasizes the necessity of continuing to investigate and develop alternative medicines, particularly in light of antibiotic resistance and the global impact of sepsis. RESEARCH HIGHLIGHTS: The study explored the potential medicinal benefits of pomegranate peel-derived silver nanoparticles (PGNP) in the treatment of sepsis. PGNP suppressed pro-inflammatory cytokines and enhanced the immune response. The study recommends PGNP as a viable substitute treatment.

Universal Risk Factors for Mortality in Bloodstream Infections (UNIFORM): a systematic review and Delphi survey

BACKGROUND

Significant variations in the variables collected in clinical studies focusing on bacteraemia lead to inconsistency in the evaluation of risk factors for mortality.

OBJECTIVE

We aimed to define a minimum set of risk factors that should be assessed and reported in all studies assessing survival in bacteraemia.

STUDY ELIGIBILITY

We conducted a systematic review including observational prospective and retrospective cohort studies that assessed all-cause mortality among patients with bacteraemia. We included only studies computing an adjusted analysis for mortality, with >500 participants.

EXPOSURES

Independently significant risk factors for all-cause, preferably 30-day, mortality.

DATA SOURCES

PubMed was used to identify eligible studies published between 2000 and 2020. A Delphi survey among experts was used to evaluate and prioritize the factors identified by the systematic review.

RISK OF BIAS

SIGN checklist complemented by risk of bias assessment of the adjusted analysis.

DATA SYNTHESIS

Definite universal risk factors were defined as those assessed in >50% of all included studies and significant in >50% of those. Potential universal risk factors were defined as those significant in >50% of studies evaluating the factor and a subgroup analysis was performed for studies of Staphylococcus aureus bacteraemia.

RESULTS

We included in the systematic review 62 studies, comprising more than 300,000 patients, from which a list of 17 risk factors was derived, whose association with all-cause mortality was statistically significant in most studies. The factors address baseline patient variables, the setting of infection acquisition, factors associated with the specific infection, the inflammatory response at onset of sepsis and management parameters where relevant. There were 14 risk factors for S. aureus bacteraemia.

CONCLUSION

We identified a minimum set of universal factors to be collected, reported, and assessed, in all future studies evaluating factors associated with mortality in bacteraemia to improve study quality and harmonization.

Antimicrobial susceptibility testing data analysis over 3 years at the Yaoundé General Hospital, Cameroon

Background

Antimicrobial resistance (AMR) is a major health concern with high rates in low-income countries. Bacteriology laboratories sustain the fight against AMR by providing antibiotic susceptibility testing (AST) results to ensure appropriate therapies. These laboratories generate a lot of data, which are usually used for prospective interventions. Our study conducted in a lower-middle-income hospital setting aimed to describe the profile of bacteria isolated from the specimens received over 3 years, assess their susceptibility profile and identify potential gaps or area of improvement from the analysis of our data.

Methods

Monthly data were retrieved from registers for all specimens received between January 2020 until December 2022. Data were compiled and analysed using the R and WHONET software.

Results

Out of 3582 specimens received, 797 were culture positive (22.3%). Escherichia coli and Klebsiella pneumoniae were frequently isolated (30.5% and 24.2%, respectively). AST results analysis showed high resistance of Gram-negative bacteria to penams and cephems, whereas low resistance was observed to carbapenems. Susceptibility to antibiotics based on the AWaRe antibiotic classification was variable. The bacteriological profile in the various types of specimen was established and rational information to design a therapeutic protocol adapted to our hospital setting was obtained.

Conclusions

AST results may not only be used for prospective guidance for treatment, but rather cumulative data analysis can contribute to design effective antibiotic prescriptions and improve general practices at the laboratory. This is, however, dependent on a good record-keeping, standardization of practices and collaboration between clinicians and laboratory scientists.

Transient bacteremia following the removal of four different types of rapid palatal expanders

PURPOSE

General health related recommendations for prophylactic measures in connection with orthodontic treatments are limited due to the lack of evidence-based data. This study aimed to investigate the development of transient bacteremia following the removal of four types of rapid palatal expanders (RPE).

METHODS

Seventy-five individuals aged 10-18 years undergoing rapid palatal expansion with four types of RPE were categorized according to the type of RPE used in their treatment: banded tooth-borne (group A (1), n = 17), banded tooth- and tissue-borne (group A (2), n = 17), bonded tooth-borne (group B (1), n = 18), and bonded tooth- and tissue-borne (group B (2), n = 23). Gingival inflammation was assessed using the gingival index one day before RPE removal. Furthermore, samples of blood (5 ml each) were collected before and 3 min after RPE removal. The groups were statistically evaluated for comparability with respect to sex, age, or wear time of the RPE and to the gingival index. In addition, the prevalence of bacteremia in the different groups was evaluated and statistically compared.

RESULTS

No significant difference was found among the groups (p > 0.05) for sex, age, and RPE wear time. Mean gingival index was higher in group B (2) than in group A (1) (p < 0.05). The prevalence of bacteremia did not differ significantly between groups. Streptococcus species were identified in all bacteremia cases. The bacteremia prevalence of the groups was as follows: group A (1), 11.8%; group A (2), 23.5%; group B (1), 16.7%; and group B (2), 30.4%.

CONCLUSION

This investigation demonstrated that removal of a RPE could cause bacteremia, but the RPE design did not affect the prevalence of bacteremia. The results of this study support the necessity of prophylaxis measures before RPE removal in indicated patients.

Nanomaterial-based methods for sepsis management

Sepsis is a serious disease caused by an impaired host immune response to infection, resulting in organ dysfunction, tissue damage and is responsible for high in-hospital mortality (approximately 20%). Recently, WHO documented sepsis as a global health priority. Nevertheless, there is still no effective and specific therapy for clinically detecting sepsis. Nanomaterial-based approaches have appeared as promising tools for identifying bacterial infections. In this review, recent biosensors are introduced and summarized as nanomaterial-based platforms for sepsis management and severe complications. Biosensors can be used as tools for the diagnosis and treatment of sepsis and as nanocarriers for drug delivery. In general, diagnostic methods for sepsis-associated bacteria, biosensors developed for this purpose are presented in detail, and their strengths and weaknesses are discussed. In other words, readers of this article will gain a comprehensive understanding of biosensors and their applications in sepsis management.

An early warning model for predicting major adverse kidney events within 30 days in sepsis patients

Background

In sepsis patients, kidney damage is among the most dangerous complications, with a high mortality rate. In addition, major adverse kidney events within 30 days (MAKE30) served as a comprehensive and unbiased clinical outcome measure for sepsis patients due to the recent shift toward targeting patient-centered renal outcomes in clinical research. However, the underlying predictive model for the prediction of MAKE30 in sepsis patients has not been reported in any study.

Methods

A cohort of 2,849 sepsis patients from the Medical Information Mart for Intensive Care (MIMIC)-IV database was selected and subsequently allocated into a training set (n = 2,137, 75%) and a validation set (n = 712, 25%) through randomization. In addition, 142 sepsis patients from the Xi'An No. 3 Hospital as an external validation group. Univariate and multivariate logistic regression analyses were conducted to ascertain the independent predictors of MAKE30. Subsequently, a nomogram was developed utilizing these predictors, with an area under curve (AUC) above 0.6. The performance of nomogram was assessed through calibration curve, receiver operating characteristics (ROC) curve, and decision curve analysis (DCA). The secondary outcome was 30-day mortality, persistent renal dysfunction (PRD), and new renal replacement therapy (RRT). MAKE30 were a composite of death, PRD, new RRT.

Results

The construction of the nomogram was based on several independent predictors (AUC above 0.6), including age, respiratory rate (RR), PaO2, lactate, and blood urea nitrogen (BUN). The predictive model demonstrated satisfactory discrimination for MAKE30, with an AUC of 0.740, 0.753, and 0.821 in the training, internal validation, and external validation cohorts, respectively. Furthermore, the simple prediction model exhibited superior predictive value compared to the SOFA model in both the training (AUC = 0.710) and validation (AUC = 0.692) cohorts. The nomogram demonstrated satisfactory calibration and clinical utility as evidenced by the calibration curve and DCA. Additionally, the predictive model exhibited excellent accuracy in forecasting 30-day mortality (AUC = 0.737), PRD (AUC = 0.639), and new RRT (AUC = 0.846) within the training dataset. Additionally, the model displayed predictive power for 30-day mortality (AUC = 0.765), PRD (AUC = 0.667), and new RRT (AUC = 0.783) in the validation set.

Conclusion

The proposed nomogram holds the potential to estimate the risk of MAKE30 promptly and efficiently in sepsis patients within the initial 24 h of admission, thereby equipping healthcare professionals with valuable insights to facilitate personalized interventions.

Gut microbiota and sepsis and sepsis-related death: a Mendelian randomization investigation

Background

It is unclear what the causal relationship is between the gut microbiota and sepsis. Therefore, we employed Mendelian randomization (MR) to determine whether a causal link exists between the two.

Methods

This study used publicly available genome-wide association studies (GWAS) summary data of gut microbiota, sepsis, sepsis (critical care), and sepsis (28-day death in critical care) to perform a two-sample MR analysis. To ensure the robustness of the results, we also conducted a sensitivity analysis.

Results

For sepsis susceptibility, inverse variance weighted (IVW) estimates revealed that Victivallales (OR = 0.86, 95% CI, 0.78-0.94, p = 0.0017) was protective against sepsis, while Lentisphaerae (OR = 0.89, 95% CI, 0.80-0.99), Gammaproteobacteria (OR = 1.37, 95% CI, 1.08-1.73), Clostridiaceae1 (OR = 1.21, 95% CI, 1.04-1.40), RuminococcaceaeUCG011 (OR = 1.10, 95% CI, 1.01-1.20), Dialister (OR = 0.85, 95% CI, 0.74-0.97), and Coprococcus2 (OR = 0.81, 95% CI, 0.69-0.94) presented a suggestive association with the development of sepsis (all p < 0.05). For sepsis (critical care), IVW estimates indicated that Lentisphaerae (OR = 0.70, 95% CI, 0.53-0.93), Victivallales (OR = 0.67, 95% CI, 0.50-0.91), Anaerostipes (OR = 0.49, 95% CI, 0.31-0.76), LachnospiraceaeUCG004 (OR = 0.51, 95% CI, 0.34-0.77), and Coprococcus1 (OR = 0.66, 95% CI, 0.44-0.99) showed a suggestive negative correlation with sepsis (critical care) (all p < 0.05). For sepsis (28-day death in critical care), IVW estimates suggested that four bacterial taxa had a normally significant negative correlation with the risk of sepsis-related death, including Victivallales (OR = 0.54, 95% CI, 0.30-0.95), Coprococcus2 (OR = 0.34, 95% CI, 0.14-0.83), Ruminiclostridium6 (OR = 0.43, 95% CI, 0.22-0.83), and Coprococcus1 (OR = 0.45, 95% CI, 0.21-0.97), while two bacterial taxa were normally significantly positively linked to the risk of sepsis-related death, namely, Mollicutes (OR = 2.03, 95% CI, 1.01-4.08) and Bacteroidales (OR = 2.65, 95% CI, 1.18-5.96) (all p < 0.05). The robustness of the above correlations was verified by additional sensitivity analyses.

Conclusion

This MR research found that several gut microbiota taxa were causally linked to the risk of sepsis, sepsis in critical care, and sepsis-related 28-day mortality in critical care.

Bacterial vampirism mediated through taxis to serum

Bacteria of the family Enterobacteriaceae are associated with gastrointestinal (GI) bleeding and bacteremia and are a leading cause of death, from sepsis, for individuals with inflammatory bowel diseases. The bacterial behaviors and mechanisms underlying why these bacteria are prone to bloodstream entry remains poorly understood. Herein, we report that clinical isolates of non-typhoidal Salmonella enterica serovars, Escherichia coli, and Citrobacter koseri are rapidly attracted toward sources of human serum. To simulate GI bleeding, we utilized a custom injection-based microfluidics device and found that femtoliter volumes of human serum are sufficient to induce the bacterial population to swim toward and aggregate at the serum source. This response is orchestrated through chemotaxis, and a major chemical cue driving chemoattraction is L-serine, an amino acid abundant in serum that is recognized through direct binding by the chemoreceptor Tsr. We report the first crystal structures of Salmonella Typhimurium Tsr in complex with L-serine and identify a conserved amino acid recognition motif for L-serine shared among Tsr orthologues. By mapping the phylogenetic distribution of this chemoreceptor we found Tsr to be widely conserved among Enterobacteriaceae and numerous World Health Organization priority pathogens associated with bloodstream infections. Lastly, we find that Enterobacteriaceae use human serum as a source of nutrients for growth and that chemotaxis and the chemoreceptor Tsr provides a competitive advantage for migration into enterohaemorrhagic lesions. We term this bacterial behavior of taxis toward serum, colonization of hemorrhagic lesions, and the consumption of serum nutrients, as 'bacterial vampirism' which may relate to the proclivity of Enterobacteriaceae for bloodstream infections.

The suppression of sepsis-induced kidney injury via the knockout of T lymphocytes

Patients with sepsis always have a high mortality rate, and acute kidney injury (AKI) is the main cause of death. It seems obvious that the immune response is involved in this process, but the specific mechanism is unknown, especially the pathogenic role of T cells and B cells needs to be further clarified. Acute kidney injury models induced by lipopolysaccharide were established using T-cell, B-cell, and T&B cell knockout mice to elucidate the role of immune cells in sepsis. Flow cytometry was used to validate the mouse models, and the pathology can confirm renal tubular injury. LPS-induced sepsis caused significant renal pathological damage, Second-generation gene sequencing showed T cells-associated pathway was enriched in sepsis. The renal tubular injury was significantly reduced in T cell and T&B cell knockout mice (BALB/c-nu, Rag1-/-), especially in BALB/c-nu mice, with a decrease in the secretion of inflammatory cytokines in the renal tissue after LPS injection. LPS injection did not produce the same effect after the knockout of B cells. We found that blocking T cells could alleviate inflammation and renal injury caused by sepsis, providing a promising strategy for controlling renal injury.

Deployment of in-silico analysis to reveal the antibacterial profiles of Allium sativum against Aeromonas hydrophila

The key challenges in aquaculture are the emergence of antimicrobial resistance in fish cultivation due to the frequent use of antibiotics. Over the past three decades, this led to a major threat in the persistence of multidrug-resistant bacteria. Aeromonas hydrophila is a Gram-negative bacterium, a common causative agent of motile bacterial septicemia in fisheries. Combining these two key factors of the presented narrative, the essential type II topoisomerase enzyme 'DNA gyrase' (encoded by the gyrA and gyrB genes) as a potential drug target in Aeromonas hydrophila was taken, retrieve its sequence from UniProtKB (Id-A0KKQ2), constructs the 3-D structure using SWISS-MODEL (in absence of the experimental structure), and performs an in-silico screening of selected drug-like compounds (25 antibacterial phytochemicals) most of which are bioactive compounds of A. sativum through molecular docking. Quercetin a derivative of A. sativum was observed as a more potent drug molecule than other studied molecules based on ligand binding energy as docking score -7.812, showed highly encouraging results, supported by a study using structural dynamics of the receptor-ligand complex for a duration of 100 ns by Molecular Dynamic Simulations and confirm binding stability with MM-GBSA calculations. This study also provides theoretical grounds for drug discovery against other pathogenic bacteria posing threats to the ecosystem. Switching to herbal products is the best way to combat the plurality of problems to avoid seen or unseen post-treatment side effects.Communicated by Ramaswamy H. Sarma.

The Role of the Insulin/Glucose Ratio in the Regulation of Pathogen Biofilm Formation

During the management of patients in acute trauma the resulting transient hyperglycemia is treated by administration of insulin. Since the effect of insulin, a quorum sensing compound, together with glucose affects biofilm formation in a concentration-specific manner, we hypothesize that the insulin/glucose ratio over the physiologic range modulates biofilm formation potentially influencing the establishment of infection through biofilm formation.

METHODS

A variety of Gram-positive and Gram-negative bacteria were grown in peptone (1%) yeast nitrogen base broth overnight in 96-well plates with various concentrations of glucose and insulin. Biofilm formation was determined by the crystal violet staining procedure. Expression of insulin binding was determined by fluorescent microscopy (FITC-insulin). Controls were buffer alone, insulin alone, and glucose alone.

RESULTS

Overall, maximal biofilm levels were measured at 220 mg/dL of glucose, regardless of insulin concentration (10, 100, 200 µU/mL) of the organism tested. In general, insulin with glucose over the range of 160-180 mg/dL exhibited a pattern of biofilm suppression. However, either above or below this range, the presence of insulin in combination with glucose significantly modulated (increase or decrease) biofilm formation in a microbe-specific pattern. This modulation appears for some organisms to be reflective of the glucose-regulated intrinsic expression of bacterial insulin receptor expression.

CONCLUSION

Insulin at physiologic levels (normal and hyperinsulinemic) in combination with glucose can affect biofilm formation in a concentration-specific and microbe-specific manner. These findings may provide insight into the importance of co-regulation of the insulin/glucose ratio in patient management.

The roles of tissue-resident macrophages in sepsis-associated organ dysfunction

Sepsis, a syndrome caused by a dysregulated host response to infection and characterized by life-threatening organ dysfunction, particularly septic shock and sepsis-associated organ dysfunction (SAOD), is a medical emergency associated with high morbidity, high mortality, and long-term sequelae. Tissue-resident macrophages (TRMs) are a subpopulation of macrophages derived primarily from yolk sac progenitors and fetal liver during embryogenesis, located primarily in non-lymphoid tissues in adulthood, capable of local self-renewal independent of hematopoiesis, and developmentally and functionally restricted to the non-lymphoid organs in which they reside. TRMs are the first line of defense against life-threatening conditions such as sepsis, tumor growth, traumatic-associated organ injury, and surgical-associated injury. In the context of sepsis, TRMs can be considered as angels or demons involved in organ injury. Our proposal is that sepsis, septic shock, and SAOD can be attenuated by modulating TRMs in different organs. This review summarizes the pathophysiological mechanisms of TRMs in different organs or tissues involved in the development and progression of sepsis.

Effect of cogon grass root ethanol extract on fatty acid binding protein 4 and oxidative stress markers in a sepsis mouse model

Background: Sepsis causes several immunological and metabolic alterations that induce oxidative stress. The modulation of fatty acid-binding protein 4 (FABP4) has been shown to worsen this condition. Extract of cogon grass root (ECGR) contains flavonoids and isoeugenol compounds that exhibit anti-inflammatory and antioxidant properties. This study aimed to assess the effects of ECGR on FABP4 and oxidative stress-related factors in a sepsis mouse model. Methods: Twenty-nine male mice ( Mus musculus) of the Deutsche Denken Yoken strain were divided into four groups: group 1, control; group 2, mice treated with 10 μL/kg body weight (BW) lipopolysaccharide (LPS); and groups 3 and 4, mice pre-treated with 90 and 115 mg/kg BW, respectively, and then treated with 10 μL/kg BW LPS for 14 d. Blood, liver, lymph, and cardiac tissue samples were collected and subjected to histological and complete blood examinations. Antioxidant (Glutathione peroxidase 3 (GPx3) and superoxide dismutase), FABP4 levels, and immune system-associated biomarker levels (TNF-α, IL-6 and IL-1β) were measured. Results: Significant increases in platelet levels (p = 0.03), cardiomyocyte counts (p =0.004), and hepatocyte counts (p = 0.0004) were observed in group 4 compared with those in group 2. Conversely, compared with those in group 2, there were significant decreases in TNF-α expression in group 3 (p = 0.004), white pulp length and width in group 4 (p = 0.001), FABP4 levels in groups 3 and 4 (p = 0.015 and p = 0.012, respectively), lymphocyte counts in group 4 (p = 0.009), and monocyte counts (p = 0.000) and polymorphonuclear cell counts in the livers (p = 0.000) and hearts (p = 0.000) of groups 3 and 4. Gpx3 activity was significantly higher in group 3 than in group 1 (p = 0.04). Conclusions: ECGR reduces FABP4 level and modulating oxidative stress markers in sepsis mouse model.

Evolving biofilm inhibition and eradication in clinical settings through plant-based antibiofilm agents

BACKGROUND

After almost 100 years since evidence of biofilm mode of growth and decades of intensive investigation about their formation, regulatory pathways and mechanisms of antimicrobial tolerance, nowadays there are still no therapeutic solutions to eradicate bacterial biofilms and their biomedical related issues.

PURPOSE

This review intends to provide a comprehensive summary of the recent and most relevant published studies on plant-based products, or their isolated compounds with antibiofilm activity mechanisms of action or identified molecular targets against bacterial biofilms. The objective is to offer a new perspective of most recent data for clinical researchers aiming to prevent or eliminate biofilm-associated infections caused by bacterial pathogens.

METHODS

The search was performed considering original research articles published on PubMed, Web of Science and Scopus from 2015 to April 2023, using keywords such as "antibiofilm", "antivirulence", "phytochemicals" and "plant extracts".

RESULTS

Over 180 articles were considered for this review with a focus on the priority human pathogens listed by World Health Organization, including Pseudomonas aeruginosa, Staphylococcus aureus, Klebsiella pneumoniae and Escherichia coli. Inhibition and detachment or dismantling of biofilms formed by these pathogens were found using plant-based extract/products or derivative compounds. Although combination of plant-based products and antibiotics were recorded and discussed, this topic is currently poorly explored and only for a reduced number of bacterial species.

CONCLUSIONS

This review clearly demonstrates that plant-based products or derivative compounds may be a promising therapeutic strategy to eliminate bacterial biofilms and their associated infections. After thoroughly reviewing the vast amount of research carried out over years, it was concluded that plant-based products are mostly able to prevent biofilm formation through inhibition of quorum sensing signals, but also to disrupt mature biofilms developed by multidrug resistant bacteria targeting the biofilm extracellular polymeric substance. Flavonoids and phenolic compounds seemed the most effective against bacterial biofilms.

Multi-biological functions of intermedin in diseases

Intermedin (IMD) is a member of the calcitonin gene-related peptide (CGRP)/calcitonin (CT) superfamily, and it is expressed extensively throughout the body. The typical receptors for IMD are complexes composed of calcitonin receptor-like receptor (CLR) and receptor activity-modifying protein (RAMP), which leads to a biased activation towards Gαs. As a diagnostic and prognostic biomarker, IMD regulates the initiation and metastasis of multiple tumors. Additionally, IMD functions as a proangiogenic factor that can restrain excessive vascular budding and facilitate the expansion of blood vessel lumen, ultimately resulting in the fusion of blood vessels. IMD has protective roles in various diseases, including ischemia-reperfusion injury, metabolic disease, cardiovascular diseases and inflammatory diseases. This review systematically elucidates IMD's expression, structure, related receptors and signal pathway, as well as its comprehensive functions in the context of acute kidney injury, obesity, diabetes, heart failure and sepsis. However, the precise formation process of IMD short peptides in vivo and their downstream signaling pathway have not been fully elucidated yet. Further in-depth studies are need to translate IMD research into clinical applications.

Drug delivery based on a supramolecular chemistry approach by using chitosan hydrogels

Microbial infections are a serious healthcare related problem, causing several complications and even death. That is why, the development of new drug delivery systems with prolonged effect represents an interesting research topic. This study presents the synthesis and characterization of new hydrogels based on chitosan and three halogenated monoaldehydes. Further, the hydrogels were used as excipients for the development of drug delivery systems (DDS) by the incorporation of fluconazole, an antifungal drug. The systems were structurally characterized by Fourier Transformed Infrared Spectroscopy and Nuclear Magnetic Resonance, both methods revealing the formation of the imine linkages between chitosan and the aldehydes. The samples presented a high degree of ordering at supramolecular level, as demonstrated by WXRD and POM and a good water-uptake, reaching a maximum of 1.6 g/g. The obtained systems were biodegradable, loosing between 38 and 49 % from their initial mass in the presence of lysozyme in 21 days. The ability to release the antifungal drug in a sustained manner for seven days, along with the high values of the inhibition zone diameter, reaching a maximum of 64 mm against Candida parapsilosis for the chlorine containing sample, recommend these systems as promising materials for bioapplications.

Predicting cytokine kinetics during sepsis; a modelling framework from a porcine sepsis model with live Escherichia coli

BACKGROUND

Describing the kinetics of cytokines involved as biomarkers of sepsis progression could help to optimise interventions in septic patients. This work aimed to quantitively characterise the cytokine kinetics upon exposure to live E. coli by developing an in silico model, and to explore predicted cytokine kinetics at different bacterial exposure scenarios.

METHODS

Data from published in vivo studies using a porcine sepsis model were analysed. A model describing the time courses of bacterial dynamics, endotoxin (ETX) release, and the kinetics of TNF and IL-6 was developed. The model structure was extended from a published model that quantifies the ETX-cytokines relationship. An external model evaluation was conducted by applying the model to literature data. Model simulations were performed to explore the sensitivity of the host response towards differences in the input rate of bacteria, while keeping the total bacterial burden constant.

RESULTS

The analysis included 645 observations from 30 animals. The blood bacterial count was well described by a one-compartment model with linear elimination. A scaling factor was estimated to quantify the ETX release by bacteria. The model successfully described the profiles of TNF, and IL-6 without a need to modify the ETX-cytokines model structure. The kinetics of TNF, and IL-6 in the external datasets were well predicted. According to the simulations, the ETX tolerance development results in that low initial input rates of bacteria trigger the lowest cytokine release.

CONCLUSION

The model quantitively described and predicted the cytokine kinetics triggered by E. coli exposure. The host response was found to be sensitive to the bacterial exposure rate given the same total bacterial burden.

MCC950 improves lipopolysaccharide‑induced systemic inflammation in mice by relieving pyroptosis in blood neutrophils

Sepsis is an infection-induced systemic inflammatory response syndrome accompanied by multiple organ injury and failure. MCC950, an inhibitor of NLR family pyrin domain containing 3 (NLRP3), can alleviate the inflammatory response and relieve inflammation-induced injury. The aim of the present study was to explore the efficacy of MCC950 in lipopolysaccharide (LPS)-induced inflammation and elucidate the underlying mechanisms. Based on a prior study, C57BL/6 mice were divided into three groups: Control, LPS, and LPS + MCC950. The mice were administered 10 mg/kg LPS to induce sepsis and 10 mg/kg MCC950 to treat sepsis 6 h before and after LPS injection. Histopathological imaging revealed organ morphology and damage during inflammation, and MCC950 alleviated organ damage and dysfunction. MCC950 prevented LPS-induced inflammatory responses by reducing inflammatory cytokine levels in the blood. To explore the mechanism by which MCC950 functions, blood neutrophils were isolated and a series of tests were performed. As revealed by measuring reactive oxygen species levels and Annexin V/PI staining of neutrophils, MCC950 reduced oxidative stress and programmed death induced by LPS. Western blotting was used to assess the protein levels of pyroptosis-related markers, including GSDMD, NLRP3, and caspase-1, in neutrophils to further explore the form of death. MCC950 reduced LPS-induced pyroptosis in neutrophils. The results of the survival analysis revealed that MCC950 increased the survival rates of mice within 72 h of LPS injection. MCC950 may be an effective treatment for sepsis that targets neutrophil pyroptosis.

Biodiversity of Skin Microbiota as an Important Biomarker for Wound Healing

Cutaneous wound healing is a natural and complex repair process that is implicated within four stages. However, microorganisms (e.g., bacteria) can easily penetrate through the skin tissue from the wound bed, which may lead to disbalance in the skin microbiota. Although commensal and pathogenic bacteria are in equilibrium in normal skin, their imbalance in the wound area can cause the delay or impairment of cutaneous wounds. Moreover, skin microbiota is in constant crosstalk with the immune system and epithelial cells, which has significance for the healing of a wound. Therefore, understanding the major bacteria species in the cutaneous wound as well as their communication with the immune system has gained prominence in a way that allows for the emergence of a new perspective for wound healing. In this review, the major bacteria isolated from skin wounds, the role of the crosstalk between the cutaneous microbiome and immune system to heal wounds, the identification techniques of these bacteria populations, and the applied therapies to manipulate the skin microbiota are investigated.

Research Progress of DcR3 in the Diagnosis and Treatment of Sepsis

Decoy receptor 3 (DcR3), a soluble glycosylated protein in the tumor necrosis factor receptor superfamily, plays a role in tumor and inflammatory diseases. Sepsis is a life-threatening organ dysfunction caused by the dysregulation of the response to infection. Currently, no specific drug that can alleviate or even cure sepsis in a comprehensive and multi-level manner has been found. DcR3 is closely related to sepsis and considerably upregulated in the serum of those patients, and its upregulation is positively correlated with the severity of sepsis and can be a potential biomarker for diagnosis. DcR3 alone or in combination with other markers has shown promising results in the early diagnosis of sepsis. Furthermore, DcR3 is a multipotent immunomodulator that can bind FasL, LIGHT, and TL1A through decoy action, and block downstream apoptosis and inflammatory signaling. It also regulates T-cell and macrophage differentiation and modulates immune status through non-decoy action; therefore, DcR3 could be a potential drug for the treatment of sepsis. The application of DcR3 in the treatment of a mouse model of sepsis also achieved good efficacy. Here, we introduce and discuss the progress in, and suggest novel ideas for, research regarding DcR3 in the diagnosis and treatment of sepsis.

Lipid oxidation dysregulation: an emerging player in the pathophysiology of sepsis

Sepsis is a life-threatening organ dysfunction caused by abnormal host response to infection. Millions of people are affected annually worldwide. Derangement of the inflammatory response is crucial in sepsis pathogenesis. However, metabolic, coagulation, and thermoregulatory alterations also occur in patients with sepsis. Fatty acid mobilization and oxidation changes may assume the role of a protagonist in sepsis pathogenesis. Lipid oxidation and free fatty acids (FFAs) are potentially valuable markers for sepsis diagnosis and prognosis. Herein, we discuss inflammatory and metabolic dysfunction during sepsis, focusing on fatty acid oxidation (FAO) alterations in the liver and muscle (skeletal and cardiac) and their implications in sepsis development.

A Review of the Antibacterial, Fungicidal and Antiviral Properties of Selenium Nanoparticles

The resistance of microorganisms to antimicrobial drugs is an important problem worldwide. To solve this problem, active searches for antimicrobial components, approaches and therapies are being carried out. Selenium nanoparticles have high potential for antimicrobial activity. The relevance of their application is indisputable, which can be noted due to the significant increase in publications on the topic over the past decade. This review of research publications aims to provide the reader with up-to-date information on the antimicrobial properties of selenium nanoparticles, including susceptible microorganisms, the mechanisms of action of nanoparticles on bacteria and the effect of nanoparticle properties on their antimicrobial activity. This review describes the most complete information on the antiviral, antibacterial and antifungal effects of selenium nanoparticles.

Effective Healing of Staphylococcus aureus-Infected Wounds in Pig Cathelicidin Protegrin-1-Overexpressing Transgenic Mice

Antimicrobial peptides (AMPs) are promising alternatives to existing treatments for multidrug-resistant bacteria-infected wounds. Therefore, the effect of protegrin-1 (PG1), a potent porcine AMP with broad-spectrum activity, on wound healing was evaluated. PG1-overexpressing transgenic mice were used as an in vivo model to evaluate its healing efficiency against Staphylococcus aureus-infected (10⁶ colony forming units) wounds. We analyzed the wounds under four specific conditions in the presence or absence of antibiotic treatment. We observed the resolution of bacterial infection and formation of neo-epithelium in S. aureus-infected wounds of the mice, even without antibiotic treatment, whereas all wild-type mice with bacterial infection died within 8 to 10 days due to uncontrolled bacterial proliferation. Interestingly, the wound area on day 7 was smaller (p < 0.01) in PG1 transgenic mice than that in the other groups, including antibiotic-treated mice, suggesting that PG1 exerts biological effects other than bactericidal effect. Additionally, we observed that the treatment of primary epidermal keratinocytes with recombinant PG1 enhanced cell migration in in vitro scratch and cell migration assays. This study contributes to the understanding of broad-spectrum endogenous cathelicidins with potent antimicrobial activities, such as PG1, on wound healing. Furthermore, our findings suggest that PG1 is a potent therapeutic candidate for wound healing.

Protective effect of the novel cyclic peptide ASK0912 on mice with sepsis induced by Acinetobacter baumannii

BACKGROUND

Sepsis has become a global health concern owing to its increasing incidence and high mortality rate. In the present study, we investigated a novel drug candidate ASK0912 on its protective effects in mice with Acinetobacter baumannii 20-1-induced sepsis, and studied the related mechanisms.

MATERIAL AND METHODS

To analyze the protective effect of ASK0912 on septic mice, survival rates, body temperature, organ and blood bacterial loads, white blood cell and platelet counts, organ damage, and cytokine levels were determined.

RESULTS

ASK0912 remarkably increased the survival rate of mice with sepsis induced by A. baumannii 20-1 at a low dose of 0.6 mg/kg. Rectal temperature measurements showed that ASK0912 treatment prevented the body temperature decrease of septic mice to some extent. Treatment with ASK0912 can notably reduce the organ and blood bacterial loads and alleviate platelet count reduction due to sepsis. ASK0912 attenuated organ damage, including reduced levels of total bile acids, urea, and creatinine, aggregation of inflammatory cells, and mitigation of structural changes in septic mice, as demonstrated by biochemical analysis and hematoxylin & eosin staining. Additionally, multiplex assay showed that abnormally increased cytokine levels (IL-1β, IL-3, IL-5, IL-6, IL-10, IL-13, MCP-1, RANTES, KC, MIP-1α, MIP-1β, and G-CSF) in septic mice decreased after ASK0912 treatment.

CONCLUSIONS

ASK0912 can not only improve the survival rate, hypothermia, lower the bacterial loads in the organs and blood, but also alleviate the pathophysiological manifestations such as intravascular coagulation abnormalities, organ damages, and immune system disorder of sepsis mice induced by A. baumannii 20-1.

Distinct bacterial population dynamics and disease dissemination after biofilm dispersal and disassembly

Microbial communities that form surface-attached biofilms must release and disperse their constituent cells into the environment to colonize fresh sites for continued survival of their species. For pathogens, biofilm dispersal is crucial for microbial transmission from environmental reservoirs to hosts, cross-host transmission, and dissemination of infections across tissues within the host. However, research on biofilm dispersal and its consequences in colonization of fresh sites remain poorly understood. Bacterial cells can depart from biofilms via stimuli-induced dispersal or disassembly due to direct degradation of the biofilm matrix, but the complex heterogeneity of bacterial populations released from biofilms rendered their study difficult. Using a novel 3D-bacterial "biofilm-dispersal-then-recolonization" (BDR) microfluidic model, we demonstrated that Pseudomonas aeruginosa biofilms undergo distinct spatiotemporal dynamics during chemical-induced dispersal (CID) and enzymatic disassembly (EDA), with contrasting consequences in recolonization and disease dissemination. Active CID required bacteria to employ bdlA dispersal gene and flagella to depart from biofilms as single cells at consistent velocities but could not recolonize fresh surfaces. This prevented the disseminated bacteria cells from infecting lung spheroids and Caenorhabditis elegans in on-chip coculture experiments. In contrast, EDA by degradation of a major biofilm exopolysaccharide (Psl) released immotile aggregates at high initial velocities, enabling the bacteria to recolonize fresh surfaces and cause infections in the hosts efficiently. Hence, biofilm dispersal is more complex than previously thought, where bacterial populations adopting distinct behavior after biofilm departure may be the key to survival of bacterial species and dissemination of diseases.

Liver proteomic analysis reveals the key proteins involved in host immune response to sepsis

Background

Sepsis is a serious infection-induced response in the host, which can result in life-threatening organ dysfunction. It is of great importance to unravel the relationship between sepsis and host immune response and its mechanisms of action. Liver is one of the most vulnerable organs in sepsis, however, the specific pathogenesis of septic liver injury has not been well understood at the protein level.

Methods

A total of 12 healthy Sprague-Dawley (SD) male rats aged from 6 to 8 weeks were adaptively housed in individual cages in the specific pathogen free animal room. These lab rats were grouped into two groups: treatment (N = 9) and control (N = 3) groups; only three mice from the treatment group survived and were used for subsequent experiments. A TMT-based proteomic analysis for liver tissue was performed in the septic rat model.

Results

A total of 37,012 unique peptides were identified, and then 6,166 proteins were determined, among which 5,701 were quantifiable. Compared to the healthy control group, the septic rat group exhibited 162 upregulated and 103 downregulated differentially expressed proteins (DEPs). The upregulated and downregulated DEPs were the most significantly enriched into the complement and coagulation cascades and metabolic pathways. Protein-protein interaction (PPI) analysis further revealed that the upregulated and downregulated DEPs each clustered in a PPI network. Several highly connected upregulated and downregulated DEPs were also enriched into the complement and coagulation cascades pathways and metabolic pathways, respectively. The parallel reaction monitoring (PRM) results of the selected DEPs were consistent with the results of the TMT analysis, supporting the proteomic data.

Conclusion

Our findings highlight the roles of complement and coagulation cascades and metabolic pathways that may play vital roles in the host immune response. The DEPs may serve as clinically potential treatment targets for septic liver injury.

Bacterial extracellular vesicles repress the vascular protective factor RNase1 in human lung endothelial cells

BACKGROUND

Sepsis is one of the leading causes of death worldwide and characterized by blood stream infections associated with a dysregulated host response and endothelial cell (EC) dysfunction. Ribonuclease 1 (RNase1) acts as a protective factor of vascular homeostasis and is known to be repressed by massive and persistent inflammation, associated to the development of vascular pathologies. Bacterial extracellular vesicles (bEVs) are released upon infection and may interact with ECs to mediate EC barrier dysfunction. Here, we investigated the impact of bEVs of sepsis-related pathogens on human EC RNase1 regulation.

METHODS

bEVs from sepsis-associated bacteria were isolated via ultrafiltration and size exclusion chromatography and used for stimulation of human lung microvascular ECs combined with and without signaling pathway inhibitor treatments.

RESULTS

bEVs from Escherichia coli, Klebsiella pneumoniae and Salmonella enterica serovar Typhimurium significantly reduced RNase1 mRNA and protein expression and activated ECs, while TLR2-inducing bEVs from Streptococcus pneumoniae did not. These effects were mediated via LPS-dependent TLR4 signaling cascades as they could be blocked by Polymyxin B. Additionally, LPS-free ClearColi™ had no impact on RNase1. Further characterization of TLR4 downstream pathways involving NF-кB and p38, as well as JAK1/STAT1 signaling, revealed that RNase1 mRNA regulation is mediated via a p38-dependent mechanism.

CONCLUSION

Blood stream bEVs from gram-negative, sepsis-associated bacteria reduce the vascular protective factor RNase1, opening new avenues for therapeutical intervention of EC dysfunction via promotion of RNase1 integrity. Video Abstract.

Performance of a System for Rapid Phenotypic Antimicrobial Susceptibility Testing of Gram-Negative Bacteria Directly from Positive Blood Culture Bottles

The rapid administration of optimal antimicrobial treatment is paramount for the treatment of bloodstream infections (BSIs), and rapid antimicrobial susceptibility testing (AST) results are essential. Q-linea has developed the ASTar system, a rapid phenotypic AST device. Here, we report the performance of the ASTar BC G- (Gram-negative) kit when assessed according to the ISO 20776-2:2007 standard for performance evaluation of in vitro diagnostic AST devices. The evaluated ASTar BC G- kit uses a broad panel of 23 antimicrobials for the treatment of BSIs caused by Gram-negative fastidious and nonfastidious bacteria across a range of 6 to 14 2-fold dilutions, including cefoxitin as a screening agent for AmpC-producing Enterobacterales. The ASTar system processes blood culture samples to generate data on MICs and susceptible, intermediate, or resistant (SIR) category. The automated protocol includes concentration determination and concentration adjustment to enable a controlled inoculum, followed by broth microdilution (BMD) and microscopy performed continuously to generate MIC values within approximately 6 h once the test is run on the ASTar system. The performance of the ASTar system was assessed against the ISO 20776-2:2007 standard BMD reference method. Testing was performed across three sites, with results from 412 contrived blood cultures and 74 fresh clinical blood cultures. The ASTar system was also tested for reproducibility, with triplicate testing of 11 strains. The accuracy study comprised 8,650 data points of bacterium-antimicrobial tests. The ASTar system demonstrated an overall essential agreement (EA) of 95.8% (8,283/8,650) and a categorical agreement (CA) of 97.6% (8,433/8,639) compared to the reference BMD method. The overall rate of major discrepancies (MDs) was 0.9% (62/6,845), and that of very major discrepancies (VMDs) was 2.4% (30/1,239). This study shows that the ASTar system delivers reproducible results with overall EA and CA of >95%.

Use of machine learning-based integration to develop a monocyte differentiation-related signature for improving prognosis in patients with sepsis

BACKGROUND

Although significant advances have been made in intensive care medicine and antibacterial treatment, sepsis is still a common disease with high mortality. The condition of sepsis patients changes rapidly, and each hour of delay in the administration of appropriate antibiotic treatment can lead to a 4-7% increase in fatality. Therefore, early diagnosis and intervention may help improve the prognosis of patients with sepsis.

METHODS

We obtained single-cell sequencing data from 12 patients. This included 14,622 cells from four patients with bacterial infectious sepsis and eight patients with sepsis admitted to the ICU for other various reasons. Monocyte differentiation trajectories were analyzed using the "monocle" software, and differentiation-related genes were identified. Based on the expression of differentiation-related genes, 99 machine-learning combinations of prognostic signatures were obtained, and risk scores were calculated for all patients. The "scissor" software was used to associate high-risk and low-risk patients with individual cells. The "cellchat" software was used to demonstrate the regulatory relationships between high-risk and low-risk cells in a cellular communication network. The diagnostic value and prognostic predictive value of Enah/Vasp-like (EVL) were determined. Clinical validation of the results was performed with 40 samples. The "CBNplot" software based on Bayesian network inference was used to construct EVL regulatory networks.

RESULTS

We systematically analyzed three cell states during monocyte differentiation. The differential analysis identified 166 monocyte differentiation-related genes. Among the 99 machine-learning combinations of prognostic signatures constructed, the Lasso + CoxBoost signature with 17 genes showed the best prognostic prediction performance. The highest percentage of high-risk cells was found in state one. Cell communication analysis demonstrated regulatory networks between high-risk and low-risk cell subpopulations and other immune cells. We then determined the diagnostic and prognostic value of EVL stabilization in multiple external datasets. Experiments with clinical samples demonstrated the accuracy of this analysis. Finally, Bayesian network inference revealed potential network mechanisms of EVL regulation.

CONCLUSIONS

Monocyte differentiation-related prognostic signatures based on the Lasso + CoxBoost combination were able to accurately predict the prognostic status of patients with sepsis. In addition, low EVL expression was associated with poor prognosis in sepsis.

Antibiogram of Multidrug-Resistant Bacteria Based on Sepsis Onset Location in Korea: A Multicenter Cohort Study

BACKGROUND

Administration of adequate antibiotics is crucial for better outcomes in sepsis. Because no uniform tool can accurately assess the risk of multidrug-resistant (MDR) pathogens, a local antibiogram is necessary. We aimed to describe the antibiogram of MDR bacteria based on locations of sepsis onset in South Korea.

METHODS

We performed a prospective observational study of adult patients diagnosed with sepsis according to Sepsis-3 from 19 institutions (13 tertiary referral and 6 university-affiliated general hospitals) in South Korea. Patients were divided into four groups based on the respective location of sepsis onset: community, nursing home, long-term-care hospital, and hospital. Along with the antibiogram, risk factors of MDR bacteria and drug-bug match of empirical antibiotics were analyzed.

RESULTS

MDR bacteria were detected in 1,596 (22.7%) of 7,024 patients with gram-negative predominance. MDR gram-negative bacteria were more commonly detected in long-term-care hospital- (30.4%) and nursing home-acquired (26.3%) sepsis, whereas MDR gram-positive bacteria were more prevalent in hospital-acquired (10.9%) sepsis. Such findings were consistent regardless of the location and tier of hospitals throughout South Korea. Patients with long-term-care hospital-acquired sepsis had the highest risk of MDR pathogen, which was even higher than those with hospital-acquired sepsis (adjusted odds ratio, 1.42; 95% confidence interval, 1.15-1.75) after adjustment of risk factors. The drug-bug match was lowest in patients with long-term-care hospital-acquired sepsis (66.8%).

CONCLUSION

Gram-negative MDR bacteria were more common in nursing home- and long-term-care hospital-acquired sepsis, whereas gram-positive MDR bacteria were more common in hospital-acquired settings in South Korea. Patients with long-term-care hospital-acquired sepsis had the highest the risk of MDR bacteria but lowest drug-bug match of initial antibiotics. We suggest that initial antibiotics be carefully selected according to the onset location in each patient.

Vibrio vulnificus, an Underestimated Zoonotic Pathogen

V. vulnificus, continues being an underestimated yet lethal zoonotic pathogen. In this chapter, we provide a comprehensive review of numerous aspects of the biology, epidemiology, and virulence mechanisms of this poorly understood pathogen. We will emphasize the widespread role of horizontal gene transfer in V. vulnificus specifically virulence plasmids and draw parallels from aquaculture farms to human health. By placing current findings in the context of climate change, we will also contend that fish farms act as evolutionary drivers that accelerate species evolution and the emergence of new virulent groups. Overall, we suggest that on-farm control measures should be adopted both to protect animals from Vibriosis, and also as a public health measure to prevent the emergence of new zoonotic groups.

Antimicrobial mechanism of semi-bionic extracts of three traditional medicinal plants-Rheum palmatum L., Scutellaria baicalensis Georgi, and Houttuynia cordata Thunb-That can be used as antibiotic alternatives

The Chinese traditional medicinal plants Rheum palmatum L., Scutellaria baicalensis Georgi, and Houttuynia cordata Thunb in a ratio of 108:65:27 form a compound named Dahuang Qinyu San (DQS), which inhibits and kills Escherichia coli and Salmonella to a certain extent in fish and shrimp aquaculture environments. The active ingredients quercetin, emodin, baicalin, and aloe-emodin are obtained from the semi-biomimetic extract of DQS (SEDQS). However, the antibacterial mechanism of SEDQS against Salmonella is still unclear. This study used the microwell-plate method to determine the Minimum Inhibitory Concentration (MIC) of SEDQS against Salmonella enteritidis (S. enteritidis) isolated from geese. In addition, the effect of SEDQS on the growth curve, respiratory metabolic system, cell wall, soluble protein, and nucleic acid in bacterial liquid of S. enteritidis was detected by spectrophotometer and reagent kit. The effects of SEDQS on S. enteritidis DNA, binding gel blocking, virulence gene expression, and pathogenicity-related proteins were determined by gel electrophoresis, SDS-PAGE, and fluorescence quantitative PCR. The study found that a concentration of 1/4 MIC-2 MIC (2.27-18.2 mg/ml) SEDQS can significantly inhibit the normal growth of S. enteritidis, destroy the cell membrane structure of bacteria resulting in the leak of nucleic acid, protein, and other contents (P < 0.01). It also significantly inhibited the activities of succinate dehydrogenase (SDH) and malate dehydrogenase (MDH; P < 0.01) in a concentration-dependent manner. When the concentration of SEDQS was 1/2 MIC to 2 MIC (4.55-18.2 mg/ml), the expression levels of gyrB, fimA, filC, spvR, Hcp, and vgrG virulence genes (P < 0.01) all decreased by more than 31, 11, 18, 30, 34, and 21% respectively compared with the control group. SEDQS could significantly inhibit the expression of six virulence genes and play an important role in the pathogenicity of the S. enteritidis infected host. The SEDQS could exert antibacterial pharmacological effects by inhibiting the growth and metabolism of S. enteritidis and inhibiting the expression of major virulence factors. It has potential application value as an antibiotic alternative.

Yeast Expressed Hybrid Peptide CLP Abridged Pro-Inflammatory Cytokine Levels by Endotoxin Neutralization

The aim of this study was to apply a strategy to express a recombinant CLP peptide and explore its application as a product derived from natural compounds. The amphiphilic CLP peptide was hybridized from three parent peptides (CM4, LL37, and TP5) and was considered to have potent endotoxin-neutralizing activity with minimal cytotoxic and hemolytic activity. To achieve high secretion expression, an expression vector of pPICZαA-HSA-CLP was constructed by the golden gate cloning strategy before being transformed into Pichia pastoris and integrated into the genome. The recombinant CLP was purified through the Ni-NTA affinity chromatography and analyzed by SDS-PAGE and mass spectrometry. The Limulus amebocyte lysate (LAL) test exhibited that the hybrid peptide CLP inhibited lipopolysaccharides (LPS) in a dose-dependent manner and was significantly (p < 0.05) more efficient compared to the parent peptides. In addition, it essentially diminished (p < 0.05) the levels of nitric oxide and pro-inflammatory cytokines (including TNF-α, IL6, and IL-1β) in LPS-induced mouse RAW264.7 macrophages. As an attendant to the control and the parental peptide LL37, the number of LPS-induced apoptotic cells was diminished compared to the control parental peptide LL37 (p < 0.05) with the treatment of CLP. Consequently, we concluded that the hybrid peptide CLP might be used as a therapeutic agent.

An organotypic oral mucosal infection model to study host-pathogen interactions

Early in vitro oral mucosal infection models (OMMs) failed to consider the suitability of the model environment to represent the host immune response. Denture stomatitis (DS) is mediated by Candida albicans, but the role of Staphylococcus aureus remains uncertain. A collagen hydrogel-based OMM containing HaCaT and HGF cell types was developed, characterised and employed to study of tissue invasion and pro-inflammatory cytokine production in response to pathogens. Models formed a robust epithelium. Despite their inflammatory baseline, 24-h infection with C. albicans, and/or S. aureus led to tissue invasion, and significantly upregulated IL-6 and IL-8 production by OMMs when compared to the unstimulated control. No significant difference in IL-6 or IL-8 production by OMMs was observed between single and dual infections. These attributes indicate that this newly developed OMM is suitable for the study of DS and could be implemented for the wider study of oral infection.

High-Dose Intravenous Ascorbate in Sepsis, a Pro-Oxidant Enhanced Microbicidal Activity and the Effect on Neutrophil Functions

Vitamin C (ascorbic acid), a water-soluble essential vitamin, is well-known as an antioxidant and an essential substrate for several neutrophil functions. Because of (i) the importance of neutrophils in microbial control and (ii) the relatively low vitamin C level in neutrophils and in plasma during stress, vitamin C has been studied in sepsis (a life-threatening organ dysfunction from severe infection). Surprisingly, the supraphysiologic blood level of vitamin C (higher than 5 mM) after the high-dose intravenous vitamin C (HDIVC) for 4 days possibly induces the pro-oxidant effect in the extracellular space. As such, HDIVC demonstrates beneficial effects in sepsis which might be due to the impacts on an enhanced microbicidal activity through the improved activity indirectly via enhanced neutrophil functions and directly from the extracellular pro-oxidant effect on the organismal membrane. The concentration-related vitamin C properties are also observed in the neutrophil extracellular traps (NETs) formation as ascorbate inhibits NETs at 1 mM (or less) but facilitates NETs at 5 mM (or higher) concentration. The longer duration of HDIVC administration might be harmful in sepsis because NETs and pro-oxidants are partly responsible for sepsis-induced injuries, despite the possible microbicidal benefit. Despite the negative results in several randomized control trials, the short course HDIVC might be interesting to use in some selected groups, such as against anti-biotic resistant organisms. More studies on the proper use of vitamin C, a low-cost and widely available drug, in sepsis are warranted.

10-Residue MyD88-Peptide Adopts β-Sheet Structure, Self-Assembles, Binds to Lipopolysaccharides, and Rescues Mice from Endotoxin-Mediated Lung-Infection and Death

Naturally occurring cationic antimicrobial peptides (AMPs) mostly adopt α-helical structures in bacterial membrane mimetic environments. To explore the design of novel β-sheet AMPs, we identified two short cationic amphipathic β-strand segments from the crystal structure of the innate immune protein, MyD88. Interestingly, of these, the 10-residue arginine-valine-rich synthetic MyD88-segment, KRCRRMVVVV (M3), exhibited β-sheet structure when bound to the outer membrane Gram-negative bacterial component, LPS. Isothermal titration calorimetric data showed that M3 bound to LPS with high affinity, and the interaction was hydrophobic in nature. Supporting these observations, computational studies indicated strong interactions of multiple and consecutive valine residues of M3 with the acyl chain of LPS. Moreover, M3 adopted nanosheet and nanofibrillar structure in 25% acetonitrile/water and isopropanol, respectively. M3 showed substantial antibacterial activities against both Gram-positive and Gram-negative bacteria which it appreciably retained in the presence of human serum and physiological salts. M3 was non-hemolytic against human red blood cells and non-cytotoxic to 3T3 cells up to 200 μM and to mice in vivo at a dose of 40 mg/kg. Furthermore, M3 neutralized LPS-induced pro-inflammatory responses in THP-1 cells and rat bone marrow-derived macrophages. Consequently, M3 attenuated LPS-mediated lung inflammation in mice and rescued them (80% survival at 10 mg/kg dose) against a lethal dose of LPS. The results demonstrate the identification of a 10-mer LPS-interacting, β-sheet peptide from MyD88 with the ability to form nanostructures and in vivo activity against LPS challenge in mice. The identified M3-template provides scope for designing novel bioactive peptides with β-sheet structures and self-assembling properties.

Ultrafast Determination of Antimicrobial Resistant Staphylococcus aureus Specifically Captured by Functionalized Magnetic Nanoclusters

Sepsis, the systemic response to infection, is a life-threatening situation for patients and leads to high mortality, especially when caused by antimicrobial resistant pathogens. Prompt diagnosis and identification of the pathogenic bacteria, including their antibiotic resistance, are highly desired to yield a timely decision for treatment. Here, we aim to develop a platform for rapid isolation and efficient identification of Staphylococcus aureus, the most frequently occurring pathogen in sepsis. A peptide (VPHNPGLISLQG, SA5-1), specifically binding to S. aureus, was conjugated to the PEGylated magnetic nanoclusters, successfully enabling the specific capture and enrichment of S. aureus from blood serum. Consequently, fast detection of the antimicrobial resistance of the collected S. aureus was achieved within 30 min using a novel luminescent probe. These magnetic nanoclusters manifest a promising diagnostic prospect to combat sepsis.

Antibiotic prophylaxis to prevent complications in endoscopic retrograde cholangiopancreatography: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

The prophylactic use of antibiotics in endoscopic retrograde cholangiopancreatography (ERCP) is still controversial.

AIM

To assess whether antibiotic prophylaxis reduces the rates of complications in patients undergoing elective ERCP.

METHODS

This systematic review and meta-analysis were performed following the Preferred Reporting Items for Systematic Reviews and Meta-analysis guidelines. A comprehensive search of multiple electronic databases was performed. Only randomized controlled trials were included. The outcomes analyzed included bacteremia, cholangitis, sepsis, pancreatitis, and mortality. The risk of bias was assessed by the Cochrane revised Risk-of-Bias tool for randomized controlled trials. The quality of evidence was assessed by the Grading of Recommendation Assessment, Development, and Evaluation. Meta-analysis was performed using the Review Manager 5.4 software.

RESULTS

Ten randomized controlled trials with a total of 1757 patients that compared the use of antibiotic and non-antibiotic prophylaxis in patients undergoing elective ERCP were included. There was no significant difference between groups regarding incidence of cholangitis after ERCP [risk difference (RD) = -0.02, 95% confidence interval (CI): -0.05, 0.02, P = 0.32], cholangitis in patients with suspected biliary obstruction (RD = 0.02, 95%CI: -0.08 to 0.13, P = 0.66), cholangitis on intravenous antibiotic prophylaxis (RD = -0.02, 95%CI: -0.05 to 0.01, P = 0.25), septicemia (RD = -0.02, 95%CI: -0.06 to 0.01, P = 0.25), pancreatitis (RD = -0.02, 95%CI: -0.06 to 0.01, P = 0.19), and all-cause mortality (RD = 0.00, 95%CI: -0.01 to 0.01, P = 0.71]. However, the antibiotic prophylaxis group presented a 7% risk reduction in the incidence of bacteremia (RD= -0.07, 95%CI: -0.14 to -0.01, P = 0.03).

CONCLUSION

The prophylactic use of antibiotics in patients undergoing elective ERCP reduces the risk of bacteremia but does not appear to have an impact on the rates of cholangitis, septicemia, pancreatitis, and mortality.

Disulfiram alleviates acute lung injury and related intestinal mucosal barrier impairment by targeting GSDMD-dependent pyroptosis

BACKGROUND

Pyroptosis was implicated in acute lung injury (ALI). Disulfiram is reported as an effective pyroptosis inhibitor by inhibiting gasdermin D(GSDMD). However, the function of pyroptosis executor GSDMD and treatment of disulfiramon on ALI, especially whether it was involved in ALI-associated intestinal mucosal barrier impairment remains unclear. This study aims to explore the role of pyroptosis and disulfiram' treatment on ALI and related intestinal mucosal barrier impairment.

METHODS

First, we established lipopolysaccharide (LPS)-induced ALI models in wild-type and Gsdmd knockout (Gsdmd^-/-), to detect the effect of pyroptosis on ALI-related intestinal mucosal barrier impairment. Furthermore, we used wild-type mice treated with disulfiram to investigate the treatment of disulfiram on ALI and related intestinal mucosal barrier impairment.

RESULTS

The data showed that GSDMD-mediated pyroptosis was activated in both lung and intestinal mucosa tissues in LPS-induced ALI, and deficiency of Gsdmd ameliorated LPS-induced ALI and related intestinal mucosal barrier damage. We also disclosed that disulfiram inhibited the pyroptosis level, and alleviated ALI and related intestinal mucosal barrier impairment induced by LPS.

CONCLUSION

These findings suggested the role of GSDMD-mediated pyroptosis and the potential application treatment of disulfiram in ALI and related intestinal mucosal barrier damage.

Comparative metagenomic analysis of human intervertebral disc nucleus pulposus and cartilaginous end plates

Study design

The diversity of microflora inhabiting endplate (EP) and nucleus pulposus (NP) tissues of human intervertebral disc (IVD) was profiled through NGS-supported 16S rRNA amplicon sequencing. Sixteen EP and their corresponding NP were excised from the brain-dead voluntary organ donors with no clinical history of low back pain, and 12 herniated and 8 degenerated NP tissues isolated from the patients undergoing spinal surgery were subjected to study the alteration in the microbial diversity.

Objective(s)

To understand in normal IVD, whether the colonization of bacteria to the NP is through the EP in discs with intact annulus fibrosus. To identify significantly differing microbial population(s) between normal and diseased IVD (NP).

Background of the study

There is increasing evidence for subclinical infection by fastidious low, growing bacteria to be a cause of disc degeneration. Although the presence of bacteria in NP has been reported well in literature, the source of bacteria is not clearly proved as the disc is avascular in healthy condition. Documentation of similar bacterial populations in the EP and NP may add proof that bacterial inoculation of NP occurs via the EP.

Materials and methods

Sixteen EP and their corresponding NP excised from brain-dead voluntary organ donors with no history of back pain and 20 diseased discs collected from patients undergoing microdiscectomy/fusion surgery were used for profiling microbiome through 16S rRNA amplicon sequencing using primers specific for V1-V9 hypervariable regions. Changes in bacterial diversity and abundance were analysed to identify the key microbial populations in normal IVD NP and EP tissues and those significantly altered in diseased IVD (NP).

Results

NP and EP shared a similar spectrum of microbiome but with varying abundance. The five dominant phyla identified were Proteobacteria, Firmicutes, Actinobacteria, OD1, and Bacteroidetes. Proteobacteria was found to be the most abundant phyla in both NP (62%) and EP (53%) of the normal IVD. This was followed by Firmicutes (16%), Actinobacteriota (11%), OD1 (Parcubacteria) (7.6%), and Bacteroidetes (2%) in NP and Firmicutes (23.4%), OD1 (Parcubacteria) (17.6%), Actinobacteriota (2.8%), and Bacteroidetes (2.6%) in EP, respectively. Under diseased conditions, Proteobacteria (68%) was dominant when compared with other phyla. However, there was no significant difference in the abundance of Proteobacteria between the normal and diseased discs. Interestingly, the other dominant phyla such as Firmicutes (Normal-NP: 16.2%; Diseased-NP: 4.02%) and Actinobacteria (Normal-NP: 11%; Diseased-NP: 0.99%) showed a significant reduction in degenerated discs. To understand the key microbial populations that are significantly altered during disease, correlation analysis was performed among the three phyla, which revealed a negative correlation in the ratio of Actinobacteria + Firmicutes vs. Proteobacteria (p = 0.001) in DD.

Conclusion

Results of our study clearly demonstrated a similar bacterial diversity but with varying abundance between the EP and NP, suggesting the existence of the endplate–nucleus pulposus axis in the normal IVD microbiome. Further, our results have indicated that the changes in the abundance of Actinobacteria + Firmicutes vs. Proteobacteria during DDD need further investigation.

A Predictive Model Based on Inflammatory and Coagulation Indicators for Sepsis-Induced Acute Kidney Injury

Background

Sepsis-induced acute kidney injury (S-AKI) is associated with systemic inflammatory responses and coagulation system dysfunction, and it is associated with an increased risk of mortality. However, there was no study to explore the predictive value of inflammatory and coagulation indicators for S-AKI.

Methods

In this retrospective study, 1051 sepsis patients were identified and divided into a training cohort (75%, n = 787) and a validation cohort (25%, n = 264) in chronological order according to the date they were admitted. Univariate analyses and multivariate logistic regression analyses were performed to identify the independent predictors of S-AKI. The logistic regression analyses (enter methods) were used to conducted the prediction models. The ROC curves were used to determine the predictive value of the constructed models on S-AKI. To test whether the increase in the AUC is significant, we used a two-sided test for ROC curves available online (http://vassarstats.net/roc_comp.html). The secondary outcome was different AKI stages and major adverse kidney events within 30 days (MAKE30). Stage 3B of S-AKI was defined as both meeting the stage 3 criteria [increase of Cr level by > 300% (≥ 4.0 mg/dL with an acute increase of ≥ 0.5 mg/dL) and/or UO < 0.3 mL/kg/h for > 24 h or anuria for > 12 h and/or acute kidney replacement therapy] and having cystatin C positive. MAKE30 were a composite of death, new renal replacement therapy (RRT), or persistent renal dysfunction (PRD).

Results

We discovered that cardiovascular disease, white blood cell (WBC), mean arterial pressure (MAP), platelet (PLT), serum procalcitonin (PCT), prothrombin time activity (PTA), and thrombin time (TT) were independent predictors for S-AKI. The predictive value (AUC = 0.855) of the simplest model 3 (constructed with PLT, PCT, and PTA), with a sensitivity of 77.6% and a specificity of 82.4%, had a similar predictive value comparing with the model 1 (AUC = 0.872) and the model 2 (AUC = 0.864) in the training cohort (P > 0.05). Compared with the model 1 (AUC = 0.888) and the model 2 (AUC = 0.887), the model 3 (AUC = 0.887) had a similar predictive value in the validation cohort. Moreover, model 3 had the best predictive power for predicting S-AKI in the stage 3 (AUC = 0.777), especially in stage 3B (AUC = 0.771). Finally, the model 3 (AUC = 0.843) had perfect predictive power for predicting MAKE30 in sepsis patients.

Conclusion

Within 24 hours after admission, the simplest model 3 (constructed with PLT, PCT, and PTA) might be a robust predictor of the S-AKI in sepsis patients, providing information for timely and efficient intervention.

Role of succinic acid in the regulation of sepsis

Sepsis is a life-threatening disease characterized by a defensive response to damage. The immune response in patients with sepsis is overenhanced in the early stages and suppressed in the later stages, leading to poor prognosis. Metabolic reprogramming and epigenetic changes play a role in sepsis. Metabolic intermediates such as elevated succinic acid levels are significantly altered in patients with sepsis. Succinic acid, a metabolic intermediate of the tricarboxylic acid cycle, participates in energy supply and plays a role in metabolic reprogramming. Simultaneously, as an epigenetic regulator, it participates in gene transcription, translation, and post-translational modifications. It also participates in the inflammatory response, hypoxia, and the production of reactive oxygen species via endocrine and paracrine pathways. In this review, we have discussed the effects of succinic acid on sepsis and its therapeutic potential.

Awareness of the Influence of Periodontitis on Systemic Health among Medical Professionals: A Questionnaire Study

Background Periodontitis is a chronic inflammatory disease of the periodontium, characterized by progressive destruction of supporting periodontal structures. However, the periodontal infection can enter into the systemic circulation and affect different organs in the body, and systemic diseases may be aggravated by periodontal disease.

Aim The aim of this study is to evaluate the knowledge of medical professionals regarding periodontal disease and its correlation with systemic disease.

Materials and Methods The survey was conducted in different government/private hospitals in and around Mangaluru city, Karnataka, India. The online survey form was circulated among various medical practitioners between June and August 2019. There was a total of 10 questions in the questionnaire, and the respondents were asked to mark their appropriate choices. Using SPSS version 16, the data collected were compiled and analyzed.

Results A total of 186 general practitioners were involved in the study. About 75.4% of practitioners were aware of periodontal disease and 73.7% of practitioners were aware of the association between periodontitis and cardiovascular diseases. Moreover, 88.1% have referred their patients to a dentist. Among the medical doctors practicing in and around Mangaluru city, this survey showed that knowledge about the relationship between oral health and general health was good.

Conclusion This study emphasizes on increasing the awareness regarding periodontal and systemic interrelationships among physicians and more comprehensive and collective efforts by both the general physicians and dental surgeons to improve overall health through improving oral health.

Effect of New 2-Thioxoimidazolidin-4-one Compounds against Staphylococcus aureus Clinical Strains and Immunological Markers’ Combinations

Although the structure-activity relationship indicates that the 4-thioxoimidazolidin ring is essential for antibacterial activities and pharmaceutical applications, there were no enough studies on the derivatives of this compound. Evaluating the new hydantoin compounds C5 (3-((2-bromobenzylidene) amino)-2- thioxoimidazolidin-4-one) and C6 (3-((4- methoxybenzylidene) amino)-2-thioxoimidazolidin-4-one) that were prepared against clinical Staphylococcus aureus isolates for antibacterial, antibiofilm, and antihemagglutination activities is the aim of this study. Therefore, the potential clinical resistance of the strains was evaluated by their ability to form biofilms, antibiotic resistance, and agglutinate erythrocytes macroscopically and microscopically; besides, the bacterial biofilm was screened for any association with the patient's serum immunoglobulin levels and complements. Despite the effective concentration for C5 and C6 compounds, which is ≤ 31.25 μg/ml, the reduction rate is not concentration-dependent; it depends on the molecular docking of the hydantoin compounds. Hence, the effect of the minimal inhibitory concentrations (MICs) is variable. In this study, the results for the compounds (with the concentration of 31.25–62.5 μg/mL for C5 and 62.5–125 μg/mL for C6) significantly manifest the antibacteria, antibiofilm, and antihemagglutination effects against the virulent strains of S. aureus due to the high percentage of biofilm inhibition that was caused by the new hydantoin compounds. Besides, time-kill kinetics studies showed that these compounds pose bactericidal action. Overall, this study revealed that the new hydantoin derivatives have an interesting potential as new antibacterial drugs through the inhibition of bacterial adhesion. The infections of these isolates activate the complement system through the lectin pathway. Nevertheless, these compounds can be improved in order to be used at even lower concentrations.

Lung Organoids—The Ultimate Tool to Dissect Pulmonary Diseases?

Organoids are complex multicellular three-dimensional (3D) in vitro models that are designed to allow accurate studies of the molecular processes and pathologies of human organs. Organoids can be derived from a variety of cell types, such as human primary progenitor cells, pluripotent stem cells, or tumor-derived cells and can be co-cultured with immune or microbial cells to further mimic the tissue niche. Here, we focus on the development of 3D lung organoids and their use as disease models and drug screening tools. We introduce the various experimental approaches used to model complex human diseases and analyze their advantages and disadvantages. We also discuss validation of the organoids and their physiological relevance to the study of lung diseases. Furthermore, we summarize the current use of lung organoids as models of host-pathogen interactions and human lung diseases such as cystic fibrosis, chronic obstructive pulmonary disease, or SARS-CoV-2 infection. Moreover, we discuss the use of lung organoids derived from tumor cells as lung cancer models and their application in personalized cancer medicine research. Finally, we outline the future of research in the field of human induced pluripotent stem cell-derived organoids.

Burden of bacterial bloodstream infections and recent advances for diagnosis

Bloodstream infections (BSIs) and subsequent organ dysfunction (sepsis and septic shock) are conditions that rank among the top reasons for human mortality and have a great impact on healthcare systems. Their treatment mainly relies on the administration of broad-spectrum antimicrobials since the standard blood culture-based diagnostic methods remain time-consuming for the pathogen's identification. Consequently, the routine use of these antibiotics may lead to downstream antimicrobial resistance and failure in treatment outcomes. Recently, significant advances have been made in improving several methodologies for the identification of pathogens directly in whole blood especially regarding specificity and time to detection. Nevertheless, for the widespread implementation of these novel methods in healthcare facilities, further improvements are still needed concerning the sensitivity and cost-effectiveness to allow a faster and more appropriate antimicrobial therapy. This review is focused on the problem of BSIs and sepsis addressing several aspects like their origin, challenges, and causative agents. Also, it highlights current and emerging diagnostics technologies, discussing their strengths and weaknesses.