The long-time consequences of systemic inflammation and sepsis on t-cell immunity

Systemic Inflammatory Response Syndromes (SIRS), including sepsis, describe a broad spectrum of immunological disorders with a very heterogeneous clinical manifestation. A SIRS caused by infectious triggers is defined as sepsis and with mortality rates exceeding 30% and totally 56000 deaths per annum, septic syndromes are the third most common causes of death after cardiovascular diseases and cancer in Germany. Acute episodes of SIRS and sepsis are characterised by an excessive and de-regulated inflammatory host response leading to organ and tissue damage and most fatally to death. The uncontrolled release of pro- and anti-inflammatory immune mediators is the root of immune suppressive states in patients at acute and post-acute stages of the disease. Malfunction of T-cells, a major component of adaptive immunity, has been shown to contribute to acute disease-induced immunosuppression but very little is known about the functional state of T-cells at post-acute and late stages of SIRS and sepsis. The present thesis provides an in-depth analysis of T-cell immunity at post-acute of SIRS and sepsis. Four different murine disease models were employed to account for the large clinical heterogeneity of the syndromes. The data presented here show that SIRS and sepsis lead to protracted systemic loss of T-cells but do not induce persistent cellular defects in adaptive T-cell function. T-cell activation and responses were intensively characterised by the examination of activation marker up-regulation, T-cell proliferation capacity and detailed T-cell receptor signalling studies. T-cell analyses were extended by the employment of secondary infection models allowing to investigate antigen-specific effector T-cell responses on multiple levels, including cytokine production and activation marker up-regulation. Ex vivo and in vivo effector T-cell studies in background of secondary infections confirm that SIRS and sepsis do not induce protracted inherent alterations in T-cell function

Low Proportion of Linezolid and Daptomycin Resistance Among Bloodborne Vancomycin-Resistant Enterococcus faecium and Methicillin-Resistant Staphylococcus aureus Infections in Europe

Vancomycin-resistant Enterococcus faecium (VREF) and methicillin-resistant Staphylococcus aureus (MRSA) are associated with significant health burden. We investigated linezolid and daptomycin resistance among VREF and MRSA in the EU/EEA between 2014 and 2018. Descriptive statistics and multivariable logistic regression were used to analyze 6,949 VREF and 35,131 MRSA blood isolates from patients with bloodstream infection. The population-weighted mean proportion of linezolid resistance in VREF and MRSA between 2014 and 2018 was 1.6% (95% CI 1.33–2.03%) and 0.28% (95% CI 0.32–0.38%), respectively. Daptomycin resistance in MRSA isolates was similarly low [1.1% (95% CI 0.75–1.6%)]. On the European level, there was no temporal change of daptomycin and linezolid resistance in MRSA and VREF. Multivariable regression analyses showed that there was a higher likelihood of linezolid and daptomycin resistance in MRSA (aOR: 2.74, p < 0.001; aOR: 2.25, p < 0.001) and linezolid in VREF (aOR: 1.99, p < 0.001) compared to their sensitive isolates. The low proportion of linezolid and daptomycin resistance in VREF and MRSA suggests that these last-resort antibiotics remain effective and will continue to play an important role in the clinical management of these infections in Europe. However, regional and national efforts to contain antimicrobial resistance should continue to monitor the trend through strengthened surveillance that includes genomic surveillance for early warning and action.Peer Reviewe

The Containment Scouts: First Insights into an Initiative to Increase the Public Health Workforce for Contact Tracing during the COVID-19 Pandemic in Germany

The COVID-19 pandemic in Germany has demanded a substantially larger public health workforce to perform contact tracing and contact management of COVID-19 cases, in line with recommendations of the World Health Organization (WHO). In response, the Robert Koch Institute (RKI) established the national “Containment Scout Initiative” (CSI) to support the local health authorities with a short-term workforce solution. It is part of a range of measures for strengthening the public health system in order to limit the spread of SARS-CoV-2 in Germany. The CSI is an example of how solutions to address critical health system capacity issues can be implemented quickly. It also demonstrates that medical or health-related backgrounds may not be necessary to support health authorities with pandemic-specific tasks and fulfil accurate contact tracing. However, it is a short-term solution and cannot compensate for the lack of existing qualified staff as well as other deficits that exist within the public health sector in Germany. This article describes the structure and process of the first phase of this initiative in order to support health policymakers, public health practitioners, and researchers considering innovative and flexible approaches for addressing urgent workforce capacity issues.Peer Reviewe

The epidemiology of carbapenem resistance in Acinetobacter baumannii complex in Germany (2014–2018): an analysis of data from the national Antimicrobial Resistance Surveillance system

Background Carbapenem-resistant Acinetobacter baumannii complex (CRABC) has globally emerged as a serious public health challenge. This study aimed to describe epidemiological trends and risk factors of carbapenem resistance in A. baumannii complex isolates in Germany between 2014 and 2018. Methods We analysed 43,948 clinical A. baumannii complex isolates using 2014 to 2018 data from the German Antimicrobial Resistance Surveillance system. We applied descriptive statistics and uni- and multivariable regression analyses to investigate carbapenem resistance in A. baumannii complex isolates. Results The proportion of carbapenem resistance in clinical A. baumannii complex isolates declined from 7.6% (95% confidence interval [95% CI] 4.4–12.7%) in 2014 to 3.5% (95% CI 2.5–4.7%) in 2018 (adjusted OR [aOR] 0.85 [95% CI 0.79–0.93, p ≤ 0.001]). Higher mean CRABC proportions for 2014 to 2018 were observed in secondary care hospitals (4.9% [95% CI 3.2–7.5%], aOR 3.6 [95% CI 2.4–5.3, p ≤ 0.001]) and tertiary care hospitals (5.9% [95% CI 3.0–11.2%], aOR 5.4 [95% CI 2.9–10.0, p ≤ 0.001) compared to outpatient clinics (1.3% [95% CI 1.1–1.6%]). CRABC proportions in hospitals varied between German regions and ranged between 2.4% (95% CI 1.6–3.5%) in the Southeast and 8.8% (95% CI 4.2–17.3%) in the Northwest. Lower CRABC proportions were observed in younger patients (< 1 year: 0.6% [95% CI 0.2–1.3%]; 1–19 years: 1.3% [95% CI 0.7–2.5%]) than adults (20–39 years: 7.7% [95% CI 4.4–13.0%]; 40–59 years: 6.2% [4.2–8.9%]; 60–79 years: 5.8% [95% CI 4.0–8.3%]). In the 20–39 year old patient age group, CRABC proportions were significantly higher for men than for women (14.6% [95% CI 8.6–23.6%] vs. 2.5% [95% CI 1.3–4.5%]). A. baumannii complex isolates from lower respiratory infections were more likely to be carbapenem-resistant than isolates from upper respiratory infections (11.4% [95% CI 7.9–16.2%] vs. 4.0% [95% CI 2.7–6.0%]; adjusted OR: 1.5 [95% CI 1.2–1.9, p ≤ 0.001]). Conclusions In contrast to many other regions worldwide, carbapenem resistance proportions among clinical A. baumannii complex isolates are relatively low in Germany and have declined in the last few years. Ongoing efforts in antibiotic stewardship and infection prevention and control are needed to prevent the spread of carbapenem-resistant A. baumannii complex in Germany.Peer Reviewe

Clinical epidemiology and case fatality due to antimicrobial resistance in Germany: a systematic review and meta-analysis, 1 January 2010 to 31 December 2021

Background Antimicrobial resistance (AMR) is of public health concern worldwide. Aim We aimed to summarise the German AMR situation for clinicians and microbiologists. Methods We conducted a systematic review and meta-analysis of 60 published studies and data from the German Antibiotic-Resistance-Surveillance (ARS). Primary outcomes were AMR proportions in bacterial isolates from infected patients in Germany (2016–2021) and the case fatality rates (2010–2021). Random and fixed (common) effect models were used to calculate pooled proportions and pooled case fatality odds ratios, respectively. Results The pooled proportion of meticillin resistance in Staphylococcus aureus infections (MRSA) was 7.9% with a declining trend between 2014 and 2020 (odds ratio (OR) = 0.89; 95% CI: 0.886–0.891; p  70%) across studies reporting resistance proportions. Conclusion Continuous efforts in AMR surveillance and infection prevention and control as well as antibiotic stewardship are needed to limit the spread of AMR in Germany.Peer Reviewe

Single cell analysis in native tissue: Quantification of the retinoid content of hepatic stellate cells

Hepatic stellate cells (HSCs) are retinoid storing cells in the liver: The retinoid content of those cells changes depending on nutrition and stress level. There are also differences with regard to a HSC’s anatomical position in the liver. Up to now, retinoid levels were only accessible from bulk measurements of tissue homogenates or cell extracts. Unfortunately, they do not account for the intercellular variability. Herein, Raman spectroscopy relying on excitation by the minimally destructive wavelength 785 nm is introduced for the assessment of the retinoid state of single HSCs in freshly isolated, unprocessed murine liver lobes. A quantitative estimation of the cellular retinoid content is derived. Implications of the retinoid content on hepatic health state are reported. The Raman-based results are integrated with histological assessments of the tissue samples. This spectroscopic approach enables single cell analysis regarding an important cellular feature in unharmed tissue

Antimicrobial Resistance and the Spectrum of Pathogens in Dental and Oral-Maxillofacial Infections in Hospitals and Dental Practices in Germany

Data on microbiological profiles in odontogenic infections are scarce. This study aimed to analyze the spectrum of pathogens and antimicrobial resistance in clinical isolates from dental and oral-maxillofacial clinical settings in Germany. We analyzed 20,645 clinical isolates (dental practices: n = 5,733; hospitals: n = 14,912) from patients with odontogenic infections using data (2012–2019) from the German Antimicrobial-Resistance-Surveillance (ARS) system. A total of 224 different species from 73 genera were found in clinical isolates from dental practices, and 329 different species from 97 genera were identified in isolates from hospital patients. In both hospitals and dental practices Streptococcus spp. (33 and 36%, respectively) and Staphylococcus spp. (21 and 12%, respectively) were the most frequently isolated microorganisms. In Streptococcus spp. isolates from hospitals, penicillin and aminopenicillin resistance proportions were 8.0% (95%CI 4.7–14.9%) and 6.9% (95%CI 4.7–9.9%), respectively. Substantially lower resistance proportions of penicillin and aminopenicillin were observed in dental practices [2.6% (95%CI 1.4–4.7%) and 2.1% (95%CI 1.1–4.0%), respectively]. Among Staphylococcus aureus isolates from hospital patients methicillin resistance proportions were 12.0% (95%CI 9.7–14.8%), which was higher than in isolates from dental practices (5.8% (95%CI 4.1–8.1%)]. High clindamycin and macrolide resistance proportions (>17%) were observed in Streptococcus spp. and Staphylococcus aureus isolates. In Klebsiella spp. isolates carbapenem resistance proportions were <1%. In sum, substantial antibiotic resistance was observed in isolates from odontogenic infections, which calls for strengthened efforts in antibiotic stewardship and infection prevention and control measures in both hospitals and dental practices.Peer Reviewe

Feedback activation of neurofibromin terminates growth factor-induced Ras activation.

BACKGROUND: Growth factors induce a characteristically short-lived Ras activation in cells emerging from quiescence. Extensive work has shown that transient as opposed to sustained Ras activation is critical for the induction of mitogenic programs. Mitogen-induced accumulation of active Ras-GTP results from increased nucleotide exchange driven by the nucleotide exchange factor Sos. In contrast, the mechanism accounting for signal termination and prompt restoration of basal Ras-GTP levels is unclear, but has been inferred to involve feedback inhibition of Sos. Remarkably, how GTP-hydrolase activating proteins (GAPs) participate in controlling the rise and fall of Ras-GTP levels is unknown. RESULTS: Monitoring nucleotide exchange of Ras in permeabilized cells we find, unexpectedly, that the decline of growth factor-induced Ras-GTP levels proceeds in the presence of unabated high nucleotide exchange, pointing to GAP activation as a major mechanism of signal termination. Experiments with non-hydrolysable GTP analogues and mathematical modeling confirmed and rationalized the presence of high GAP activity as Ras-GTP levels decline in a background of high nucleotide exchange. Using pharmacological and genetic approaches we document a raised activity of the neurofibromatosis type I tumor suppressor Ras-GAP neurofibromin and an involvement of Rsk1 and Rsk2 in the down-regulation of Ras-GTP levels. CONCLUSIONS: Our findings show that, in addition to feedback inhibition of Sos, feedback stimulation of the RasGAP neurofibromin enforces termination of the Ras signal in the context of growth-factor signaling. These findings ascribe a precise role to neurofibromin in growth factor-dependent control of Ras activity and illustrate how, by engaging Ras-GAP activity, mitogen-challenged cells play safe to ensure a timely termination of the Ras signal irrespectively of the reigning rate of nucleotide exchange.We acknowledge funding by the German research council (DFG), grant # RU 860/4-1 (AH), by the Federal Ministry of Education and Research (BMBF), Germany, FKZ: 01EO1002 (I.R., R.M.), by the BBSRC and through the BBSRC Midlands Interdisciplinary BioSciences Training Partnership (MAE-F) (GL - BB/G01227X/1 and BB/M00015X/1) and the National Council on Science and Technology of Mexico (CONACYT) (MAE-F).This is the final published version. It first appeared at http://biosignaling.biomedcentral.com/articles/10.1186/s12964-016-0128-z

Raman spectroscopy follows time-dependent changes in T lymphocytes isolated from spleen of endotoxemic mice

T lymphocytes (T cells) are highly specialized members of the adaptive immune system and hold the key to the understanding the hosts’ response toward invading pathogen or pathogen-associated molecular patterns such as LPS. In this study, noninvasive Raman spectroscopy is presented as a label-free method to follow LPS-induced changes in splenic T cells during acute and postacute inflammatory phases (1, 4, 10, and 30 d) with a special focus on CD4+ and CD8+ T cells of endotoxemic C57BL/6 mice. Raman spectral analysis reveals highest chemical differences between CD4+ and CD8+ T cells originating from the control and LPS-treated mice during acute inflammation, and the differences are visible up to 10 d after the LPS insult. In the postacute phase, CD4+ and CD8+ T cells from treated and untreated mice could not be differentiated anymore, suggesting that T cells largely regained their original status. In sum, the biological information obtained from Raman spectra agrees with immunological readouts demonstrating that Raman spectroscopy is a well-suited, label-free method for following splenic T cell activation in systemic inflammation from acute to postacute phases. The method can also be applied to directly study tissue sections as is demonstrated for spleen tissue one day after LPS insult.T lymphocytes (T cells) are highly specialized members of the adaptive immune system and hold the key to the understanding the hosts’ response toward invading pathogen or pathogen-associated molecular patterns such as LPS. In this study, noninvasive Raman spectroscopy is presented as a label-free method to follow LPS-induced changes in splenic T cells during acute and postacute inflammatory phases (1, 4, 10, and 30 d) with a special focus on CD4+ and CD8+ T cells of endotoxemic C57BL/6 mice. Raman spectral analysis reveals highest chemical differences between CD4+ and CD8+ T cells originating from the control and LPS-treated mice during acute inflammation, and the differences are visible up to 10 d after the LPS insult. In the postacute phase, CD4+ and CD8+ T cells from treated and untreated mice could not be differentiated anymore, suggesting that T cells largely regained their original status. In sum, the biological information obtained from Raman spectra agrees with immunological readouts demonstrating that Raman spectroscopy is a well-suited, label-free method for following splenic T cell activation in systemic inflammation from acute to postacute phases. The method can also be applied to directly study tissue sections as is demonstrated for spleen tissue one day after LPS insult

Global Report on the epidemiology and burden on sepsis: current evidence, identifying gaps and future directions

Sepsis is a preventable, life-threatening condition marked by severe organ dysfunction. For 2017, it was estimated that it had affected 49 million individuals and was related to approximately 11 million potentially avoidable deaths worldwide. Sepsis mortality is often related to suboptimal quality of care, an inadequate health infrastructure, poor infection prevention measures in place, late diagnosis, and inappropriate clinical management. Antimicrobial resistance further complicates sepsis management across all settings, particularly in high-risk populations, such as neonates and patients in intensive care units (ICUs). While primary infections have remained the leading cause of sepsis and sepsis-related mortality over the last three decades, there has been a marked increase in the proportion of sepsis incidence and mortality linked to injuries and non-communicable diseases. Moreover, survivors of sepsis face serious long-term health consequences in the form of increased post-discharge mortality, physical and cognitive impairment, and mental health disorders. Unfortunately, high-quality epidemiological data on the burden of sepsis are limited by inconsistent and variable diagnostic criteria, few prospective studies, and suboptimal administrative data and hospital discharge coding