Current spectrum of causative pathogens in sepsis: A prospective nationwide cohort study in Japan

TLR4/TNFR1 blockade suppresses STAT1/STAT3 expression and increases SOCS3 expression in modulation of LPS-induced macrophage responses

Due to the urgent need to create appropriate treatment techniques, which are currently unavailable, LPS-induced sepsis has become a serious concern on a global scale. The primary active component in the pathophysiology of inflammatory diseases such as sepsis is the Gram-negative bacterial lipopolysaccharide (LPS). LPS interacts with cell surface TLR4 in macrophages, causing the formation of reactive oxygen species (ROS), TNF-α, IL-1β and oxidative stress. It also significantly activates the MAPKs and NF-κB pathway. Excessive production of pro-inflammatory cytokines is one of the primary characteristic features in the onset and progression of inflammation. Cytokines mainly signal through the JAK/STAT pathway. We hypothesize that blocking of TLR4 along with TNFR1 might be beneficial in suppressing the effects of STAT1/STAT3 due to the stimulation of SOCS3 proteins. Prior to the LPS challenge, the macrophages were treated with antibodies against TLR4 and TNFR1 either individually or in combination. On analysis of the macrophage populations by flowcytometry, it was seen that receptor blockade facilitated the phenotypic shift of the M1 macrophages towards M2 resulting in lowered oxidative stress. Blocking of TLR4/TNFR1 upregulated the SOCS3 and mTOR expressions that enabled the transition of inflammatory M1 macrophages towards the anti-inflammatory M2 phenotype, which might be crucial in curbing the inflammatory responses. Also the reduction in the production of inflammatory cytokines such as IL-6, IL-1β due to the reduction in the activation of the STAT1 and STAT3 molecules was observed in our combination treatment group. All these results indicated that neutralization of both TLR4 and TNFR1 might provide new insights in establishing an alternative therapeutic strategy for LPS-sepsis.

Exploring the relationship between HCMV serostatus and outcomes in COVID-19 sepsis

Background

Sepsis, a life-threatening condition caused by the dysregulated host response to infection, is a major global health concern. Understanding the impact of viral or bacterial pathogens in sepsis is crucial for improving patient outcomes. This study aimed to investigate the human cytomegalovirus (HCMV) seropositivity as a risk factor for development of sepsis in patients with COVID-19.

Methods

A multicenter observational study enrolled 95 intensive care patients with COVID-19-induced sepsis and 80 post-surgery individuals as controls. HCMV serostatus was determined using an ELISA test. Comprehensive clinical data, including demographics, comorbidities, and 30-day mortality, were collected. Statistical analyses evaluated the association between HCMV seropositivity and COVID-19 induced sepsis.

Results

The prevalence of HCMV seropositivity did not significantly differ between COVID-19-induced sepsis patients (78%) and controls (71%, p = 0.382) in the entire cohort. However, among patients aged ≤60 years, HCMV seropositivity was significantly higher in COVID-19 sepsis patients compared to controls (86% vs 61%, respectively; p = 0.030). Nevertheless, HCMV serostatus did not affect 30-day survival.

Discussion

These findings confirm the association between HCMV seropositivity and COVID-19 sepsis in non-geriatric patients. However, the lack of an independent effect on 30-day survival can be explained by the cross-reactivity of HCMV specific CD8+ T-cells towards SARS-CoV-2 peptides, which might confer some protection to HCMV seropositive patients. The inclusion of a post-surgery control group strengthens the generalizability of the findings. Further research is needed to elucidate the underlying mechanisms of this association, explore different patient populations, and identify interventions for optimizing patient management.

Conclusion

This study validates the association between HCMV seropositivity and severe COVID-19-induced sepsis in non-geriatric patients, contributing to the growing body of evidence on viral pathogens in sepsis. Although HCMV serostatus did not independently influence 30-day survival, future investigations should focus on unraveling the intricate interplay between HCMV, immune responses, and COVID-19. These insights will aid in risk stratification and the development of targeted interventions for viral sepsis.

Burden of Antimicrobial Resistance in Japan: A Systematic Literature Review and Meta-Analysis

INTRODUCTION

Antimicrobial resistance (AMR) is one of the most serious public health challenges worldwide, including in Japan. However, there is limited evidence assessing the AMR burden in Japan. Thus, this systematic literature review (SLR) and meta-analysis (MA) were conducted to assess the clinical and economic burden of AMR in Japan.

METHODS

Comprehensive literature searches were performed on EMBASE, MEDLINE, the Cochrane Library, and ICHUSHI between 2012 and 2022 following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. MA estimated a pooled effect between the two comparative arms (AMR vs. non-AMR). The results were reported in measures of odds ratios (ORs) for in-hospital mortality and in standardized mean differences (SMDs) for length of stay (LOS) and direct medical costs.

RESULTS

Literature searches identified 1256 de-duplicated records, of which 56 observational studies (English, n = 35; Japanese, n = 21) were included. Of note, twenty-two studies (39.3%) compared the AMR group with non-AMR group. In the SLR, in-hospital mortality, LOS, and direct medical costs were higher in the AMR group compared to the non-AMR group. Eight studies were selected for the MA. In the AMR group, the pooled estimate showed a statistically higher in-hospital mortality [random effect (RE)-OR 2.25, 95% CI 1.34-3.79; I2 = 89%; τ2 = 0.2257, p < 0.01], LOS (RE-SMD 0.37, 95% CI  - 0.09-0.84; I2 = 99%; τ2 = 0.3600, p < 0.01), and direct medical cost (RE-SMD 0.53, 95% CI 0.43-0.62; I2 = 0.0%; τ2 = 0.0, p = 0.88) versus the non-AMR group.

CONCLUSION

Our study presents an overview of the clinical and economic burden of AMR in Japan. Patients with AMR infections experience significantly higher in-hospital mortality, LOS, and direct medical costs compared with patients without AMR infections.

Blood microbial signatures associated with mortality in patients with sepsis: A pilot study

Sepsis is a life-threatening illness caused by the dysregulated host response to infection. Nevertheless, our current knowledge of the microbial landscape in the blood of septic patients is still limited. Next-generation sequencing (NGS) is a sensitive method to quantitatively characterize microbiomes at various sites of the human body. In this study, we analyzed the blood microbial DNA of 22 adult patients with sepsis and 3 healthy subjects. The presence of non-human DNA was identified in both healthy and septic subjects. Septic patients had a markedly altered microbial DNA profile compared to healthy subjects over α- and β-diversity. Unexpectedly, the patients could be further divided into two subgroups (C1 and C2) based on β-diversity analysis. C1 patients showed much higher bacteria, viruses, fungi, and archaea abundance, and a higher level of α-diversity (Chao1, Observed and Shannon index) than both C2 patients and healthy subjects. The most striking difference was seen in the case of Streptomyces violaceusniger, Phenylobacterium sp. HYN0004, Caulobacter flavus, Streptomyces sp. 11-1-2, and Phenylobacterium zucineum, the abundance of which was the highest in the C1 group. Notably, C1 patients had a significantly poorer outcome than C2 patients. Moreover, by analyzing the patterns of microbe-microbe interactions in healthy and septic subjects, we revealed that C1 and C2 patients exhibited distinct co-occurrence and co-exclusion relationships. Together, our study uncovered two distinct microbial signatures in the blood of septic patients. Compositional and ecological analysis of blood microbial DNA may thus be useful in predicting mortality of septic patients.

Applications of peptides in nanosystems for diagnosing and managing bacterial sepsis

Sepsis represents a critical medical condition stemming from an imbalanced host immune response to infections, which is linked to a significant burden of disease. Despite substantial efforts in laboratory and clinical research, sepsis remains a prominent contributor to mortality worldwide. Nanotechnology presents innovative opportunities for the advancement of sepsis diagnosis and treatment. Due to their unique properties, including diversity, ease of synthesis, biocompatibility, high specificity, and excellent pharmacological efficacy, peptides hold great potential as part of nanotechnology approaches against sepsis. Herein, we present a comprehensive and up-to-date review of the applications of peptides in nanosystems for combating sepsis, with the potential to expedite diagnosis and enhance management outcomes. Firstly, sepsis pathophysiology, antisepsis drug targets, current modalities in management and diagnosis with their limitations, and the potential of peptides to advance the diagnosis and management of sepsis have been adequately addressed. The applications have been organized into diagnostic or managing applications, with the last one being further sub-organized into nano-delivered bioactive peptides with antimicrobial or anti-inflammatory activity, peptides as targeting moieties on the surface of nanosystems against sepsis, and peptides as nanocarriers for antisepsis agents. The studies have been grouped thematically and discussed, emphasizing the constructed nanosystem, physicochemical properties, and peptide-imparted enhancement in diagnostic and therapeutic efficacy. The strengths, limitations, and research gaps in each section have been elaborated. Finally, current challenges and potential future paths to enhance the use of peptides in nanosystems for combating sepsis have been deliberately spotlighted. This review reaffirms peptides' potential as promising biomaterials within nanotechnology strategies aimed at improving sepsis diagnosis and management.

Using the Traditional Ex Vivo Whole Blood Model to Discriminate Bacteria by Their Inducible Host Responses

Whole blood models are rapid and versatile for determining immune responses to inflammatory and infectious stimuli, but they have not been used for bacterial discrimination. Staphylococcus aureus, S. epidermidis and Escherichia coli are the most common causes of invasive disease, and rapid testing strategies utilising host responses remain elusive. Currently, immune responses can only discriminate between bacterial 'domains' (fungi, bacteria and viruses), and very few studies can use immune responses to discriminate bacteria at the species and strain level. Here, whole blood was used to investigate the relationship between host responses and bacterial strains. Results confirmed unique temporal profiles for the 10 parameters studied: IL-6, MIP-1α, MIP-3α, IL-10, resistin, phagocytosis, S100A8, S100A8/A9, C5a and TF3. Pairwise analysis confirmed that IL-6, resistin, phagocytosis, C5a and S100A8/A9 could be used in a discrimination scheme to identify to the strain level. Linear discriminant analysis (LDA) confirmed that (i) IL-6, MIP-3α and TF3 could predict genera with 95% accuracy; (ii) IL-6, phagocytosis, resistin and TF3 could predict species at 90% accuracy and (iii) phagocytosis, S100A8 and IL-10 predicted strain at 40% accuracy. These data are important because they confirm the proof of concept that host biomarker panels could be used to identify bacterial pathogens.

Advances in sepsis biomarkers

Sepsis, a dysregulated host immune response to an infectious agent, significantly increases morbidity and mortality for hospitalized patients worldwide. This chapter reviews (1) the basic principles of infectious diseases, pathophysiology and current definition of sepsis, (2) established sepsis biomarkers such lactate, procalcitonin and C-reactive protein, (3) novel, newly regulatory-cleared/approved biomarkers, such as assays that evaluate white blood cell properties and immune response molecules, and (4) emerging biomarkers and biomarker panels to highlight future directions and opportunities in the diagnosis and management of sepsis.

Exploring the Relationship between Plasma Adiponectin, Gender, and Underlying Diseases in Severe Illness

Adiponectin is low in obesity, plays a crucial role in metabolic health, and, moreover, possesses immunoregulatory properties. However, studies examining its levels in patients with systemic inflammatory response syndrome (SIRS) or sepsis have yielded conflicting results. While females typically have higher systemic adiponectin levels than males, research on sex-specific associations in this context is limited. In this study of 156 SIRS/sepsis patients, including those with liver cirrhosis, we aimed to explore the relationship between plasma adiponectin, body mass index (BMI), gender, disease severity, and underlying etiological conditions. Our findings revealed that patients with liver cirrhosis, who are susceptible to infections, exhibited elevated circulating adiponectin levels, irrespective of sex. When excluding cirrhosis patients, plasma adiponectin levels were similar between male SIRS/sepsis patients and controls but lower in female patients compared to female controls. Plasma adiponectin was inversely related to BMI in female but not male patients. Further analysis within the non-cirrhosis subgroup demonstrated no significant differences in adiponectin levels between sexes among SIRS, sepsis, and septic shock patients. Ventilation, dialysis, and vasopressor therapy had no discernible impact on adiponectin levels in either sex. A negative correlation between adiponectin and C-reactive protein (CRP) existed in males only. Notably, patients with pancreatitis showed the lowest plasma adiponectin concentrations, although sex-specific differences were not significant. Infection with Gram-negative or Gram-positive bacteria had minimal effects on plasma adiponectin levels in both sexes. However, infection with the severe acute respiratory syndrome coronavirus type 2 led to decreased adiponectin levels in females exclusively. Multivariate analysis considering all factors affecting plasma adiponectin levels in males or females identified BMI in females and CRP levels in males to predict plasma adiponectin levels in SIRS/sepsis patients. Additionally, our study observed a trend where the 25 patients who did not survive had higher plasma adiponectin levels, particularly among males. In summary, our investigation highlights the influence of underlying diseases and sex on plasma adiponectin levels in SIRS/sepsis patients, shedding light on potential implications for disease management and prognosis.

Conserved metabolic regulator ArcA responds to oxygen availability, iron limitation, and cell envelope perturbations during bacteremia

IMPORTANCE

Infections of the bloodstream are life-threatening and can result in sepsis. Gram-negative bacteria cause a significant portion of bloodstream infections, which is also referred to as bacteremia. The long-term goal of our work is to understand how such bacteria establish and maintain infection during bacteremia. We have previously identified the transcription factor ArcA, which promotes fermentation in bacteria, as a likely contributor to the growth and survival of bacteria in this environment. Here, we study ArcA in the Gram-negative species Citrobacter freundii, Klebsiella pneumoniae, and Serratia marcescens. Our findings aid in determining how these bacteria sense their environment, utilize nutrients, and generate energy while countering the host immune system. This information is critical for developing better models of infection to inform future therapeutic development.

Epidemiology, Resistance Profiles, and Outcomes of Bloodstream Infections in Community-Onset Sepsis in the United States

OBJECTIVES

To describe frequency of positive blood cultures, patterns of pathogens' characteristics and their resistance profile in patients with blood cultures drawn due to a presumed diagnosis of community-onset sepsis, and to examine the association between blood culture-positive pathogens and hospital mortality.

DESIGN

Retrospective cohort study.

SETTING

Two hundred one U.S. hospitals from 2016 to 2020 using the Premier Healthcare Database.

SUBJECTS

Adult patients presenting with community-onset sepsis who had blood cultures collected within 2 days of hospital admission. We defined sepsis using the U.S. Centers for Disease Control Adult Sepsis Event Surveillance criteria.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We identified 147,061 patients with community-onset sepsis. The number of blood culture-positive sepsis episodes was 21,167 (14%) and the number of nonblood culture-positive sepsis episodes was 20,326 (14%). Among patients with blood culture-positive sepsis, Gram-negative rods were isolated in 55% of patients, Gram-positive cocci were isolated in 47%. Of those, methicillin-resistant Staphylococcus aureus (MRSA) was 11%, ceftriaxone-resistant Enterobacterales /extended-spectrum β-lactamase was 7%, and carbapenem-resistant Enterobacterales was 1.3%. The crude in-hospital mortality was 17% for culture-negative sepsis, 13% for nonblood culture-positive sepsis, and 17% for blood culture-positive sepsis. In multilevel logistic regression models, compared with culture-negative sepsis, blood culture-positive sepsis (adjusted odds ratio [aOR], 0.89; 95% CI, 0.85-0.94) and nonblood culture-positive sepsis (aOR, 0.82; 95% CI, 0.78-0.87) were associated with lower odds of in-hospital mortality. Acinetobacter species, Pseudomonas aeruginosa , methicillin-sensitive Staphylococcus aureus , and MRSA were associated with higher in-hospital mortality, whereas Escherichia coli , Klebsiella species, Proteus species, and Streptococcus species were associated with lower in-hospital mortality.

CONCLUSIONS

In patients hospitalized with community-onset sepsis, the prevalence of blood culture-positive sepsis was 14%. Among positive blood culture sepsis resistant organisms were infrequent. Compared with culture-negative sepsis, blood culture-positive sepsis and nonblood culture-positive sepsis were associated with lower in-hospital mortality.

The Role of Mesenchymal Stem Cell Secretome in the Inflammatory Mediators and the Survival Rate of Rat Model of Sepsis

In sepsis, simultaneously elevated levels of pro-inflammatory cytokines and interleukin (IL)-10 indicate immune response dysregulation, increasing the mortality of the host. As mesenchymal stem cell (MSC) secretome is known to have immunomodulatory effects, we aim to assess the role of MSC secretome in the inflammatory mediators (NF-κB p65 and p50, TNF-α, IL-10) and the survival rate of a rat model of sepsis. In this study, forty-eight male Rattus norvegicus rats were divided into one sham group and three groups with sepsis induction: the control group and the sepsis-induced rat groups treated with 150 μL (T1) and 300 μL (T2) of secretome. The survival rate was observed per 6 h for 48 h and plotted using the Kaplan-Meier method. Compared to the control group, T2 showed a significant decrease in the relative expression of NF-κB and the serum TNF-α level, and a significant increase in the serum IL-10 level. Meanwhile, T1 showed a significant decrease in the serum TNF-α level compared to the control group. The Kaplan-Meier Log Rank test did not show significance in the distribution of survival between T1, T2, and the control group. However, from the 18th to the 36th hour, the survival rate of T2 was lower than the survival rate of the control group and T1, with a noticeable difference between T2 and the control group, as well as T1 at the 36th hour. At the 42nd hour, the survival rate of T2 was the same as the control group and remained lower than T1. In conclusion, MSC secretome regulated the inflammatory mediators in rat model of sepsis, with a dose of 150 μL being more effective.

Electrochemical point-of-care devices for the diagnosis of sepsis

Sepsis is a life-threatening dysfunction of organ systems caused by a dysregulated immune system because of an infectious process. It remains one of the leading causes of hospital mortality and of hospital readmissions in the United States. Mortality from sepsis increases with each hour of delayed treatment, therefore, diagnostic devices that can reduce the time from the onset of a patient's infection to the delivery of appropriate therapy are urgently needed. Likewise, tools that are capable of high-frequency testing of clinically relevant biomarkers are required to study disease progression. Electrochemical biosensors offer important advantages such as high sensitivity, fast response, miniaturization, and low cost that can be adapted to clinical needs. In this review paper, we discuss the current state, limitations, and future directions of electrochemical-based point-of-care detection platforms that contribute to the diagnosis and monitoring of sepsis.

Detecting the performance of methicillin-resistant Staphylococcus aureus by a molecular diagnostic assay in positive blood culture: Influence of coexistence of mecA-positive bacteria and diversity in orfX-SCCmec junction region in methicillin-susceptible S. aureus

BACKGROUND

In blood cultures that test positive for staphylococcal bacteria, rapid identification of methicillin-resistant Staphylococcus aureus (MRSA) or methicillin-susceptible Staphylococcus aureus (MSSA) by molecular assay is useful for appropriate antimicrobial treatment of bloodstream infections. Although the Xpert MRSA/SA BC assay is widely available in clinical settings in Japan, its efficacy has not yet evaluated thoroughly.

METHODS

We retrospectively studied 100 blood culture cases positive for S. aureus at Sapporo Medical University Hospital between March 2019 to May 2022. Cycle threshold (CT) values for target genes from the Xpert MRSA/SA BC assay were compared to phenotypic results. Genotyping and genetic analysis of the orfX-SCCmec junction region was performed for selected isolates.

RESULTS

We analyzed 25 and 75 isolates assigned to MRSA and MSSA, respectively, using the Xpert MRSA/SA BC assay. Of these, 99 isolates from agar cultures showed compatible susceptibility to oxacillin. One genetically misidentified case of MRSA was found to be caused by the mixed growth of MSSA and methicillin-resistant S. hominis on agar culture. Of the 73 MSSA with pure growth on agar culture, 45 (61.6%) were found to be orfX-SCCmec-positive, spa-positive, and mecA-negative in this assay. These MSSA belong to diverse spa and coa types.

CONCLUSION

The Xpert MRSA/SA BC assay accurately identified MRSA and MSSA in positive blood cultures. However, over half of the MSSA isolates showed positive results for orfX-SCCmec, presumably due to genetic diversity in the orfX-associated region of MSSA. Therefore, the coexistence of MSSA and mecA-harboring coagulase-negative staphylococci may cause confusion about identification of MRSA.

One-year hospital readmission for recurrent sepsis: associated risk factors and impact on 1-year mortality-a French nationwide study

BACKGROUND

Sepsis is a complex health condition, leading to long-term morbidity and mortality. Understanding the risk factors for recurrent sepsis, as well as its impact on mid- and long-term mortality among other risk factors, is essential to improve patient survival.

METHODS

A risk factor analysis, based on French nationwide medico-administrative data, was conducted on a cohort of patients above 15 years old, hospitalized with an incident sepsis in metropolitan France between 1st January 2018 and 31st December 2018 and who survived their index hospitalization. Two main analyses, focusing on outcomes occurring 1-year post-discharge, were conducted: a first one to assess risk factors for recurrent sepsis and a second to assess risk factors for mortality.

RESULTS

Of the 178017 patients surviving an incident sepsis episode in 2018 and included in this study, 22.3% died during the 1-year period from discharge and 73.8% had at least one hospital readmission in acute care, among which 18.1% were associated with recurrent sepsis. Patients aged between 56 and 75, patients with cancer and renal disease, with a long index hospital stay or with mediastinal or cardiac infection had the highest odds of recurrent sepsis. One-year mortality was higher for patients with hospital readmission for recurrent sepsis (aOR 2.93; 99% CI 2.78-3.09). Among all comorbidities, patients with cancer (aOR 4.35; 99% CI 4.19-4.52) and dementia (aOR 2.02; 99% CI 1.90-2.15) had the highest odds of 1-year mortality.

CONCLUSION

Hospital readmission for recurrent sepsis is one of the most important risk factors for 1-year mortality of septic patients, along with age and comorbidities. Our study suggests that recurrent sepsis, as well as modifiable or non-modifiable other risk factors identified, should be considered in order to improve patient care pathway and survival.

Clinical Profile of Patients Presenting With Sepsis to the Emergency Department of a Tertiary Care Hospital in Wardha During the COVID Pandemic (June 2020-June 2021)

Background

Sepsis is defined as life-threatening organ dysfunction due to a dysregulated host response to infection. Septic shock, multi-organ dysfunction, and death occur in severe cases with reduced blood flow to vital organs. Sepsis contributes to 15-20% of all global deaths. Through this study, we intend to evaluate the clinical profile and study the common blood investigatory panels along with organisms causing sepsis in patients presenting with sepsis in the emergency department during the COVID pandemic. In addition, the study was also done to estimate the prevalence of sepsis and compare patients having sepsis with serum lactate, sepsis with Systemic Inflammatory Response Syndrome (SIRS) criteria, and sepsis with quick Sepsis Related Organ Failure Assessment (qSOFA) score.

Method

Observational retrospective study to evaluate patients presenting with sepsis diagnosed by the Third International Consensus Definitions for Sepsis and Septic Shock” criteria presenting to the emergency department of Acharya Vinoba Bhave Rural Hospital (AVBRH) affiliated to Jawaharlal Nehru Medical College (JNMC), Wardha during COVID pandemic (June 2020-June 2021).

Results

The majority of the patients presented with fever (42%), and very few presented with altered mental status (8%). Seventy-four percent of the study population did not show any bacterial growth on blood culture, but out of the remaining 26%, blood culture, Staphylococcus aureus, Pseudomonas aeruginosa, and Klebsiella pnemoniae were the significant microbes. Amongst qSOFA, SIRS criteria, and serum lactate as a screening tool for sepsis, SIRS is the most sensitive for screening sepsis patients.

Conclusion

Staphylococcus aureus, Pseudomonas aerugenosa, and Klebsiella pneumoniae were the major contributors in the development of sepsis in COVID-19-associated infection. The presence of raised leukocyte counts and serum lactate should alarm clinicians of possible sources of infection. The timely initiation, rapid de-escalation of empirical antibiotics, and strict compliance with infection control practices should be accomplished to reduce the occurrence of multidrug resistance organisms.

Study of the Antimicrobial Activity of the Chinese Dong Ethnic Minority Medicine, Madeng’ai

The overuse of antibiotics has contributed to the emergence of multidrug-resistant bacteria, which poses a challenging task for clinical therapy. Thus, new agents with antibiotic efficacy against multidrug-resistant infections are needed. The traditional Dong ethnic minority medicines have emerged as a new source for prodrug selection. Among them, Madeng'ai (PotentillafreynianaBornm) is widely used by the folk for anti-infection and wound healing, although the mechanisms remain unclear. In this study, the antimicrobial activities of Dong medicine Madeng'ai were evaluated both in vitro and in vivo. S. aureus, E. coli, E. faecalis, P. aeruginosa, K. pneumoniae, and A. baumannii were cultured in LB media, different concentrations of Madeng'ai powder solution were added to the LB agar plates to evaluate minimal inhibitory concentration. An animal study was performed on a mouse excisional wound model combined with bacterial solution injection in the wound area. After Madeng'ai or PBS treatment, hematoxylin and eosin analysis were used for pathological analysis of skin tissues from the infected area. Madeng'ai powder solution over 2 mg/mL concentration completely inhibited E. coli growth. At 4.0 mg/mL, Madeng'ai significantly inhibited the growth of E. faecalis, Pseudomonas aeruginosa (PAE), Klebsiella pneumoniae, and Acinetobacter baumannii. The mouse model revealed that Madeng'ai could suppress the growth of MRSA and PAE and accelerate healing of cutaneous wounds. Madeng'ai, a newly discovered Dong ethnic minority medicine possesses considerable antimicrobial activity against both human normal pathogenic bacteria and multiresistance bacteria such as Pseudomonas aeruginosa, S. aureus, and Acinetobacter baumannii. Therefore, Madeng'ai has great potential for further study and clinical application.

Changes in Biomarkers and Hemodynamics According to Antibiotic Susceptibility in a Model of Bacteremia

Proper selection of susceptible antibiotics in drug-resistant bacteria is critical to treat bloodstream infection. Although biomarkers that guide antibiotic therapy have been extensively evaluated, little is known about host biomarkers targeting in vivo antibiotic susceptibility. Therefore, we aimed to evaluate the trends of hemodynamics and biomarkers in a porcine bacteremia model treated with insusceptible antibiotics compared to those in susceptible models. Extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (E. coli, 5.0 * 10^9 CFU) was intravenously administered to 11 male pigs. One hour after bacterial infusion, pigs were assigned to two groups of antibiotics, ceftriaxone (n = 6) or ertapenem (n = 5). Pigs were monitored up to 7 h after bacterial injection with fluid and vasopressor support to maintain the mean arterial blood pressure over 65 mmHg. Blood sampling for blood culture and plasma acquisition was performed before and every predefined hour after E. coli injection. Cytokine (tumor necrosis factor-α, interleukin [IL]-1β, IL-6, IL-8, IL-10, C-reactive protein, procalcitonin, presepsin, heparan sulfate, syndecan, and soluble triggering receptor expressed on myeloid cells-1 [sTREM-1]) levels in plasma were analyzed using enzyme-linked immunosorbent assays. Bacteremia developed after intravenous injection of E. coli, and negative conversion was confirmed only in the ertapenem group. While trends of other biomarkers failed to show differences, the trend of sTREM-1 was significantly different between the two groups (P = 0.0001, two-way repeated measures analysis of variance). Among hemodynamics and biomarkers, the sTREM-1 level at post 2 h after antibiotics administration represented a significant difference depending on susceptibility, which can be suggested as a biomarker candidate of in vivo antibiotics susceptibility. Further clinical studies are warranted for validation.

IMPORTANCE Early and appropriate antibiotic treatment is a keystone in treating patients with sepsis. Despite its importance, blood culture which requires a few days remains as a pillar of diagnostic method for microorganisms and their antibiotic susceptibility. Whether changes in biomarkers and hemodynamics indicate treatment response of susceptible antibiotic compared to resistant one is not well understood to date. In this study using extended-spectrum β-lactamase -producing E. coli bacteremia porcine model, we have demonstrated the comprehensive cardiovascular hemodynamics and trends of plasma biomarkers in sepsis and compared them between two groups with susceptible and resistant antibiotics. While other hemodynamics and biomarkers have failed to differ, we have identified that levels of soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) significantly differed between the two groups over time. Based on the data in this study, trends of sTREM-1 obtained before the antibiotics and 2~4 h after the antibiotics could be a novel host biomarker that triggers the step-up choice of antibiotics.

Evaluation of an extracorporeal ozone-based bactericide system for the treatment of Escherichia coli sepsis

BACKGROUND

Sepsis is associated with substantial mortality rates. Antibiotic treatment is crucial, but global antibiotic resistance is now classified as one of the top ten global public health risks facing humanity. Ozone (O₃) is an inorganic molecule with no evident function in the body. We investigated the bactericide properties of ozone, using a novel system of extracorporeal ozone blood treatment. We hypothesized that ozone would decrease the concentration of viable Escherichia coli (E. coli) in human whole blood and that the system would be technically feasible and physiologically tolerable in a clinically relevant model of E. coli sepsis in swine.

METHODS

The E. coli strain B09-11822, a clinical isolate from a patient with septic shock was used. The in vitro study treated E. coli infected human whole blood (n = 6) with ozone. The in vivo 3.5-h sepsis model randomized swine to E. coli infusion and ozone treatment (n = 5) or E. coli infusion and no ozone treatment (n = 5). Live E. coli, 5 × 10⁷ colony-forming units (CFU/mL) was infused in a peripheral vein. Ozone treatment was initiated with a duration of 30 min after 1.5 h.

RESULTS

The single pass in vitro treatment decreased E. coli by 27%, mean 1941 to 1422 CFU/mL, mean of differences - 519.0 (95% CI - 955.0 to - 82.98, P = 0.0281). pO₂ increased (95% CI 31.35 to 48.80, P = 0.0007), pCO₂ decreased (95% CI - 3.203 to - 1.134, P = 0.0069), oxyhemoglobin increased (95% CI 1.010 to 3.669, P = 0.0113). Methemoglobin was not affected. In the sepsis model, 9/10 swine survived. One swine randomized to ozone treatment died from septic shock before initiation of the treatment. Circulatory, respiratory, and metabolic parameters were not affected by the ozone treatment. E. coli in arterial blood, in organs and in aerobic and anaerobic blood cultures did not differ. Hemoglobin, leucocytes, and methemoglobin were not affected by the treatment.

CONCLUSIONS

Ozone decreased the concentration of viable E. coli in human whole blood. The system was technically feasible and physiologically tolerable in porcine sepsis/septic shock and should be considered for further studies towards clinical applications.

Surveillance of multidrug resistance phenotypes in Staphylococcus aureus in Japan and correlation with whole-genome sequence findings

BACKGROUND

Antimicrobial resistance in Staphylococcus aureus imposes a high disease burden. Both phenotypic and genotypic monitoring are key to understanding and containing emerging resistant strains.

AIM

Phenotypic monitoring of emerging resistance in S. aureus and correlation of priority strain phenotypes with whole genome sequencing (WGS) findings.

METHODS

Antimicrobial susceptibility test results of >40,000 isolates from 213 participating hospitals from 2011 to 2019 were exported from the national Japan Nosocomial Infections Surveillance (JANIS) database. Longitudinal and geographic distribution and prevalence of distinct multidrug resistance phenotypes ('resistance profiles') of S. aureus were examined among hospitals and prefectures. We further conducted a genome sequence analysis of strains with specific resistance profiles of concern.

FINDINGS

The overall prevalence of meticillin-resistant S. aureus (MRSA) decreased from 40.3% to 35.1% from 2011 to 2019. However, among dozens of S. aureus resistance profiles, only one profile of a type of MRSA, exhibited a statistically significant increase in inpatient frequency, exceeding 10% during the nine years. This MRSA profile showed resistance to oxacillin, erythromycin, and levofloxacin. Analysis of WGS results of S. aureus isolates with this phenotype revealed that most belonged to clonal complex 8, and all carried SCCmec IV, typical of community-acquired MRSA.

CONCLUSION

Tracking distinct resistance profiles deepened our understanding of the overall decrease in MRSA and led to recognition of the emergence of a new resistance phenotype. This study provides a model for future epidemiological research on antimicrobial resistance correlating multidrug resistance phenotypes with selective genome sequencing, which can be applied to other bacterial species.

Mesenchymal Stem Cell-Derived Exosome Therapy of Microbial Diseases: From Bench to Bed

Microbial diseases are a global health threat, leading to tremendous casualties and economic losses. The strategy to treat microbial diseases falls into two broad categories: pathogen-directed therapy (PDT) and host-directed therapy (HDT). As the typical PDT, antibiotics or antiviral drugs directly attack bacteria or viruses through discerning specific molecules. However, drug abuse could result in antimicrobial resistance and increase infectious disease morbidity. Recently, the exosome therapy, as a HDT, has attracted extensive attentions for its potential in limiting infectious complications and targeted drug delivery. Mesenchymal stem cell-derived exosomes (MSC-Exos) are the most broadly investigated. In this review, we mainly focus on the development and recent advances of the application of MSC-Exos on microbial diseases. The review starts with the difficulties and current strategies in antimicrobial treatments, followed by a comprehensive overview of exosomes in aspect of isolation, identification, contents, and applications. Then, the underlying mechanisms of the MSC-Exo therapy in microbial diseases are discussed in depth, mainly including immunomodulation, repression of excessive inflammation, and promotion of tissue regeneration. In addition, we highlight the latest progress in the clinical translation of the MSC-Exo therapy, by summarizing related clinical trials, routes of administration, and exosome modifications. This review will provide fundamental insights and future perspectives on MSC-Exo therapy in microbial diseases from bench to bedside.

Impact of beta-lactamase detection reagent on rapid diagnosis of ESBL-producing pathogens using urine samples of patients with Gram-negative bacteriuria

INTRODUCTION

The rapid increase of extended-spectrum beta-lactamase (ESBL)-producing pathogens makes it difficult to choose appropriate antimicrobials in patients with Gram-negative bacterial infection. The Cica-beta reagent (Kanto Chemical, Tokyo, Japan) is a chromogenic test that detects ESBLs from bacterial colonies. This study aimed to reveal whether Cica-beta reagent could detect ESBLs directly from urine samples to facilitate rapid diagnosis of antibiotic susceptibility.

METHODS

A prospective study was conducted from July 2019 to November 2019. Patients in whom urine culture tests were performed were eligible. Each urine sample was centrifuged, and the pellet was mixed with Cica-beta reagent. The test was considered positive when the enzymatic reaction turned from yellow to red or orange.

RESULTS

In total, 350 urine samples were analysed. Urinary tract infection (UTI) was diagnosed in 214 patients. ESBL-producing Enterobacterales were isolated from 79 samples. The Cica-beta test showed sensitivity of 79.8% and specificity of 99.3% in patients with Gram-negative bacteriuria. Sensitivity and specificity improved to 90.2% and 100%, respectively, in patients with UTI.

CONCLUSION

The Cica-beta test could be an efficient test for the detection of ESBL-producing pathogens in urine. By providing immediate information about ESBLs, it might be a useful point-of-care test to guide appropriate antimicrobial use in patients with UTI.