Risk factors for impaired respiratory function post COVID-19: A prospective cohort study of nonhospitalized and hospitalized patients.

BACKGROUND: Severe COVID-19 increases the risk for long-term respiratory impairment, but data after mild COVID-19 are scarce. Our aims were to determine risk factors for reduced respiratory function 3-6 months after COVID-19 infection and to investigate if reduced respiratory function would relate to impairment of exercise performance and breathlessness. METHODS: Patients with COVID-19 were enrolled at the University Hospitals of Umeå and Örebro, and Karlstad Central Hospital, Sweden. Disease severity was defined as mild (nonhospitalized), moderate (hospitalized with or without oxygen treatment), and severe (intensive care). Spirometry, including diffusion capacity (DLCO ), was performed 3-6 months after hospital discharge or study enrollment (for nonhospitalized patients). Breathlessness (defined as ≥1 according to the modified Medical Research Council scale) and functional exercise capacity (1-min sit-to-stand test; 1-MSTST) were assessed. RESULTS: Between April 2020 and May 2021, 337 patients were enrolled in the study. Forced vital capacity and DLCO were significantly lower in patients with severe COVID-19. Among hospitalized patients, 20% had reduced DLCO , versus 4% in nonhospitalized. Breathlessness was found in 40.6% of the participants and was associated with impaired DLCO . A pathological desaturation or heart rate response was observed in 17% of participants during the 1-MSTST. However, this response was not associated with reduced DLCO . CONCLUSION: Reduced DLCO was the major respiratory impairment 3-6 months following COVID-19, with hospitalization as the most important risk factor. The lack of association between impaired DLCO and pathological physiological responses to exertion suggests that these physiological responses are not primarily related to decreased lung function.

Ototoxicity associated with extended dalbavancin treatment for a shoulder prosthetic joint infection.

BACKGROUND: Dalbavancin is a lipoglycopeptide antibiotic approved for treatment of skin and soft tissue infections, administered as a single or two-dose treatment. The extended half-life, good penetration into bone and synovial fluid, and bactericidal activity against gram-positive bacteria, including those in biofilm, make dalbavancin an appealing choice for treatment of bone and joint infections in outpatient settings. However, we present a rare case of ototoxicity associated with off-label extended dalbavancin treatment of a prosthetic joint infection. CASE PRESENTATION: A 55-year-old man with a prosthetic joint infection of the shoulder underwent off-label extended dalbavancin treatment, receiving a cumulative dose of 2500 mg. The patient experienced a gradual onset of hearing loss following the first dose, leading to a diagnosis of bilateral sensorineural hearing loss that persisted 1 year after dalbavancin was discontinued. CONCLUSIONS: This case report highlights the importance of exercising caution when administering dalbavancin beyond approved dosing guidelines, and emphasizes the need for vigilance regarding the potential for ototoxicity.

On the twilight phenomenon of the green band.

The twilight sky is usually characterized by the well-known reddish/orange colors close to the horizon and the blue colors above. However, in many cases, a green or greenish band forms between the blue and reddish parts of the sky, and it is essentially not documented in the literature. In this study, the green band phenomenon is simulated using the radiative transfer model SCIATRAN and subsequent color modeling based on the CIE color matching functions and chromaticity values. Different parameters and processes that have a potential influence are investigated. In addition, a possible contribution by airglow emissions is discussed. The simulations show that it requires just the right intensities in the blue, green, and long-wave spectral regions to produce a green color. The total ozone column has the comparatively largest influence. This study is, to the best of our knowledge, the first detailed investigation of the green band phenomenon.

On the twilight phenomenon of the green band: publisher's note.

This publisher's note reports corrections in Appl. Opt.62, 162 (2023).APOPAI0003-693510.1364/AO.476520.

Flagellin hypervariable region determines symbiotic properties of commensal Escherichia coli strains.

Escherichia coli represents a classical intestinal gram-negative commensal. Despite this commensalism, different E. coli strains can mediate disparate immunogenic properties in a given host. Symbiotic E. coli strains such as E. coli Nissle 1917 (EcN) are attributed beneficial properties, e.g., promotion of intestinal homeostasis. Therefore, we aimed to identify molecular features derived from symbiotic bacteria that might help to develop innovative therapeutic alternatives for the treatment of intestinal immune disorders. This study was performed using the dextran sodium sulphate (DSS)-induced colitis mouse model, which is routinely used to evaluate potential therapeutics for the treatment of Inflammatory Bowel Diseases (IBDs). We focused on the analysis of flagellin structures of different E. coli strains. EcN flagellin was found to harbor a substantially longer hypervariable region (HVR) compared to other commensal E. coli strains, and this longer HVR mediated symbiotic properties through stronger activation of Toll-like receptor (TLR)5, thereby resulting in interleukin (IL)-22-mediated protection of mice against DSS-induced colitis. Furthermore, using bone-marrow-chimeric mice (BMCM), CD11c+ cells of the colonic lamina propria (LP) were identified as the main mediators of these flagellin-induced symbiotic effects. We propose flagellin from symbiotic E. coli strains as a potential therapeutic to restore intestinal immune homeostasis, e.g., for the treatment of IBD patients.

An Ultrasound Screening Exam During Medicare Wellness Visits May Be Beneficial.

OBJECTIVES: The physical exam component of a periodic health visit in the elderly has not been considered useful. Standard Medicare Wellness visits require no physical exam beyond blood pressure and most physicians perform limited exams during these visits. The objective of this study was to test the feasibility, potential benefit, and costs of performing a screening ultrasound (US) exam during Medicare Wellness visits. METHODS: A physician examiner at an academic internal medicine primary care clinic performed a screening US exam targeting important abnormalities of patients 65-85 years old during a Medicare Wellness visit. The primary care physician (PCP) recorded the follow-up items for each abnormality identified by the US examiner and assessed the benefit of each abnormality for the participant. Abnormality benefit, net exam benefit per participant, follow-up items and costs, participant survey results, and exam duration were assessed. RESULTS: Participants numbered 108. Total abnormalities numbered 283 and new diagnoses were 172. Positive benefit scores were assigned to 38.8%, neutral (zero) scores to 59.4%, and negative benefit scores to 1.8% of abnormalities. Net benefit scores per participant were positive in 63.9%, 0 in 34.3%, and negative in 1.8%. Follow-up items were infrequent resulting in 76% of participants without follow-up cost. Participant survey showed excellent acceptance of the exam. CONCLUSIONS: The US screening exam identified frequent abnormalities in Medicare Wellness patients. The assessed benefits were rarely negative and often mild to moderately positive, with important new chronic conditions identified. Follow-up costs were low when the PCPs were also US experts.

A combination of the activation marker CD86 and the immune checkpoint marker B and T lymphocyte attenuator (BTLA) indicates a putative permissive activation state of B cell subtypes in healthy blood donors independent of age and sex.

BACKGROUND: The use of anti-B cell based therapies in immune-mediated diseases targeting general B cell markers or molecules important for B cell function has increased the clinical needs of monitoring B cell subpopulations. RESULTS: We analyzed the expression profile of cell surface markers CD86 and B and T lymphocyte attenuator (BTLA) in B cell subtypes using flow cytometry, including naïve, transitional, switched memory, non-switched memory and double-negative memory B cells and plasmablasts, and investigated the dependence of age and sex in a healthy adult blood donor population. The switched memory B cell subtype displayed a divergent expression of the markers, with increased CD86 and decreased BTLA as compared to non-switched and double negative memory cells, as well as compared to naïve B cells. Plasmablasts expressed highly increased CD86 compared to all other subtypes and a decreased expression of BTLA compared to naïve cells, but still higher compared to the memory cell populations. Transitional B cells had CD86 and BTLA expression similar to the other naïve cells. CONCLUSIONS: We show divergent expression of CD86 and BTLA in memory cells and plasmablasts compared to naïve B cells independent of age and sex. Furthermore, a similarly divergent difference of expression pattern was seen between the memory cell subtypes, altogether indicating that the combination of CD86 and BTLA might be markers for a permissive activation state. We suggest the combination of CD86 and BTLA expression on B cell subtypes as a potentially important tool in monitoring the status of B cell subtypes before and after treatments influencing the B cell compartment.

Weak Agonistic LPS Restores Intestinal Immune Homeostasis.

Generated by gram-negative bacteria, lipopolysaccharides (LPSs) are one of the most abundant and potent immunomodulatory substances present in the intestinal lumen. Interaction of agonistic LPS with the host myeloid-differentiation-2/Toll-like receptor 4 (MD-2/TLR4) receptor complex results in nuclear factor κB (NF-κB) activation, followed by the robust induction of pro-inflammatory immune responses. Here we have isolated LPS from a common gut commensal, Bacteroides vulgatus mpk (BVMPK), which provides only weak agonistic activity. This weak agonistic activity leads to the amelioration of inflammatory immune responses in a mouse model for experimental colitis, and it was in sharp contrast to strong agonists and antagonists. In this context, the administration of BVMPK LPS into mice with severe intestinal inflammation re-established intestinal immune homeostasis within only 2 weeks, resulting in the clearance of all symptoms of inflammation. These inflammation-reducing properties of weak agonistic LPS are grounded in the induction of a special type of endotoxin tolerance via the MD-2/TLR4 receptor complex axis in intestinal lamina propria CD11c+ cells. Thus, weak agonistic LPS represents a promising agent to treat diseases involving pathological overactivation of the intestinal immune system, e.g., in inflammatory bowel diseases.

Plasma concentrations of secretory leukocyte protease inhibitor (SLPI) differ depending on etiology and severity in community-onset bloodstream infection.

The severity of bloodstream infections (BSI) depends on pathogen, source, and host factors. Secretory leukocyte protease inhibitor (SLPI) counteracts tissue damage, balances inflammation, and is increased in pneumonia and sepsis. We aimed to evaluate whether SLPI production differs depending on etiology, disease severity, and sex in BSI and to correlate SLPI with markers of inflammation and immunosuppression. Of the adult patients with BSI, 109 were included and sampled repeatedly, from hospital admission through day 28. Controls (blood donors) were sampled twice. SLPI in plasma was measured with enzyme-linked immunosorbent assay (ELISA) technique. Streptococcus pneumoniae and Staphylococcus aureus etiology were associated with higher SLPI than Escherichia coli on days 1-2 and 3. On day 1-2, subjects with sepsis had higher SLPI concentrations than those with non-septic BSI. Pneumonia was associated with higher SLPI than a non-pulmonary source of infection. SLPI co-varied with inflammatory markers. SLPI concentrations did not differ with regard to sex in the full cohort, but men with pneumonia had higher SLPI than women on day 1-2. S. pneumoniae and S. aureus BSI were associated with higher SLPI, when compared to E. coli. Severity and pneumonia, as well as male sex in the pneumonia sub-cohort, were factors independently associated with higher SLPI.

Bio-based succinate from sucrose: High-resolution 13C metabolic flux analysis and metabolic engineering of the rumen bacterium Basfia succiniciproducens.

Succinic acid is a platform chemical of recognized industrial value and accordingly faces a continuous challenge to enable manufacturing from most attractive raw materials. It is mainly produced from glucose, using microbial fermentation. Here, we explore and optimize succinate production from sucrose, a globally applied substrate in biotechnology, using the rumen bacterium Basfia succiniciproducens DD1. As basis of the strain optimization, the yet unknown sucrose metabolism of the microbe was studied, using 13C metabolic flux analyses. When grown in batch culture on sucrose, the bacterium exhibited a high succinate yield of 1molmol-1 and a by-product spectrum, which did not match the expected PTS-mediated sucrose catabolism. This led to the discovery of a fructokinase, involved in sucrose catabolism. The flux approach unraveled that the fructokinase and the fructose PTS both contribute to phosphorylation of the fructose part of sucrose. The contribution of the fructokinase reduces the undesired loss of the succinate precursor PEP into pyruvate and into pyruvate-derived by-products and enables increased succinate production, exclusively via the reductive TCA cycle branch. These findings were used to design superior producers. Mutants, which (i) overexpress the beneficial fructokinase, (II) lack the competing fructose PTS, and (iii) combine both traits, produce significantly more succinate. In a fed-batch process, B. succiniciproducens ΔfruA achieved a titer of 71gL-1 succinate and a yield of 2.5molmol-1 from sucrose.

Symbiotic gut commensal bacteria act as host cathepsin S activity regulators.

Cathepsin S (CTSS) is a lysosomal protease whose activity regulation is important for MHC-II signaling and subsequent activation of CD4+ T cell mediated immune responses. Dysregulation of its enzymatic activity or enhanced secretion into extracellular environments is associated with the induction or progression of several autoimmune diseases. Here we demonstrate that commensal intestinal bacteria influence secretion rates and intracellular activity of host CTSS and that symbiotic bacteria, i.e. Bacteroides vulgatus mpk, may actively regulate this process and help to maintain physiological levels of CTSS activities in order to prevent from induction of pathological inflammation. The symbiont-controlled regulation of CTSS activity is mediated by anticipating reactive oxygen species induction in dendritic cells which, in turn, maintains cystatin C (CysC) monomer binding to CTSS. CysC monomers are potent endogenous CTSS inhibitors. This Bacteroides vulgatus caused and CysC dependent CTSS activity regulation is involved in the generation of tolerant intestinal dendritic cells contributing to prevention of T-cell mediated induction of colonic inflammation. Taken together, we demonstrate that symbionts of the intestinal microbiota regulate host CTSS activity and secretion and might therefore be an attractive approach to deal with CTSS associated autoimmune diseases.

Heparin-Binding Protein Measurement Improves the Prediction of Severe Infection With Organ Dysfunction in the Emergency Department.

OBJECTIVES: Early identification of patients with infection and at risk of developing severe disease with organ dysfunction remains a difficult challenge. We aimed to evaluate and validate the heparin-binding protein, a neutrophil-derived mediator of vascular leakage, as a prognostic biomarker for risk of progression to severe sepsis with circulatory failure in a multicenter setting. DESIGN: A prospective international multicenter cohort study. SETTING: Seven different emergency departments in Sweden, Canada, and the United States. PATIENTS: Adult patients with a suspected infection and at least one of three clinical systemic inflammatory response syndrome criteria (excluding leukocyte count). INTERVENTION: None. MEASUREMENTS AND MAIN RESULTS: Plasma levels of heparin-binding protein, procalcitonin, C-reactive protein, lactate, and leukocyte count were determined at admission and 12-24 hours after admission in 759 emergency department patients with suspected infection. Patients were defined depending on the presence of infection and organ dysfunction. Plasma samples from 104 emergency department patients with suspected sepsis collected at an independent center were used to validate the results. Of the 674 patients diagnosed with an infection, 487 did not have organ dysfunction at enrollment. Of these 487 patients, 141 (29%) developed organ dysfunction within the 72-hour study period; 78.0% of the latter patients had an elevated plasma heparin-binding protein level (>30 ng/mL) prior to development of organ dysfunction (median, 10.5 hr). Compared with other biomarkers, heparin-binding protein was the best predictor of progression to organ dysfunction (area under the receiver operating characteristic curve=0.80). The performance of heparin-binding protein was confirmed in the validation cohort. CONCLUSION: In patients presenting at the emergency department, heparin-binding protein is an early indicator of infection-related organ dysfunction and a strong predictor of disease progression to severe sepsis within 72 hours.

SiiA and SiiB are novel type I secretion system subunits controlling SPI4-mediated adhesion of Salmonella enterica.

The giant non-fimbrial adhesin SiiE is essential to establish intimate contact between Salmonella enterica and the apical surface of polarized epithelial cells. SiiE is secreted by a type I secretion system (T1SS) encoded by Salmonella Pathogenicity Island 4 (SPI4). We identified SiiA and SiiB as two regulatory proteins encoded by SPI4. Mutant strains in siiA or siiB still secrete SiiE, but are highly reduced in adhesion to, and invasion of polarized cells. SiiA and SiiB are inner membrane proteins with one and three transmembrane (TM) helices respectively. TM2 and TM3 of SiiB are similar to members of the ExbB/TolQ family, while the TM of SiiA is similar to MotB and a conserved aspartate residue in this TM is essential for SPI4-encoded T1SS function. Co-immunoprecipitation, bacterial two-hybrid and FRET demonstrate homo- and heterotypic protein interactions for SiiA and SiiB. SiiB, but not SiiA also interacts with the SPI4-T1SS ATPase SiiF. The integrity of the Walker A box in SiiF was required for SiiB-SiiF interactionand SiiF dimer formation. Based on these data, we describe SiiA and SiiB as new, exclusively virulence-associated members of the Mot/Exb/Tol family of membrane proteins. Both proteins are involved in a novel mechanism of controlling SPI4-T1SS-dependent adhesion, most likely by formation of a proton-conducting channel.

Physicians' emotion awareness and emotion regulation training during medical education: a systematic scoping review protocol.

INTRODUCTION: The objective of this systematic scoping review is to identify what approaches have been implemented in medical education programmes to teach medical students the skills to identify and manage emotions that may be elicited in them during physician-patient interactions and in the clinical environment. Emotions of all involved in the clinical encounter are central to the process of clinical care. However, a gap remains addressing and teaching medical students about recognising and dealing with their own emotions. METHODS AND ANALYSIS: This scoping review will follow the updated JBI (The Johanna Briggs Institute) methodology guidance for the conduct and reporting of systematic scoping reviews, and the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews. A search strategy was developed and applied to five databases. Terms used included medical education, medical curriculum, medical students, emotion (regulation), psychological well-being and mental health. Additionally, a grey literature and reference list search will be conducted. Two independent reviewers will first screen titles and abstracts followed by a second, full-text screening phase. Publications to be included will contain information and data about teaching approaches such as lectures, and other teaching material on physicians' emotion awareness and emotion regulation training in medical education. ETHICS AND DISSEMINATION: This study will review existing literature on emotion awareness and emotion regulation training in medical education, and a systematic scoping review does not require ethical approval. The results of this scoping review will be submitted for publication to relevant peer-reviewed journals and will be used to inform the development and implementation of training programmes and research studies aimed at preparing medical students to identify and manage their own emotions in the clinical environment.

Sexual Dysfunction in Postural Orthostatic Tachycardia Syndrome (POTS): A Cross-Sectional, Case-Control Study.

Background: We aimed to determine whether patients with postural orthostatic tachycardia syndrome (POTS) have sexual dysfunction compared to age-matched healthy controls. Methods: Utilizing online COMPASS-31 to evaluate dysautonomia symptom severity, Beck's Depression Inventory Second Edition (BDII), Female Sexual Function (FSF), and International Index of Erection Function (IIEF) questionnaires, we compared sexual function scores in patients with POTS to scores obtained from sex- and age-matched healthy controls via a cross-sectional case-control study. Results: A total of 160 women with POTS, mean age 30.2 ± 7.9 (range 21-50 years), had lower FSF scores than 62 healthy age-matched female controls. IIEF scores in 29 male patients with POTS with a mean age of 30.1 ± 6.0 (range 21-47) were significantly lower than in 27 healthy age-matched male controls. Female POTS patients had significantly lower scores in the sub-domains of desire, arousal, and satisfaction, while male POTS patients had significantly lower scores in erectile and orgasmic function, desire, and satisfaction than healthy controls. Predictive factors of sexual dysfunction were depression in women and age in men. The severity of autonomic symptoms correlated with sexual dysfunction in women, but this effect disappeared after controlling for depression. Conclusions: Compared to healthy controls, women and men with POTS have significant sexual dysfunction, which needs to be considered in the diagnostic and therapeutic approaches as part of comprehensive patient care.

The Scope of Practice of an Embedded Pediatric Palliative Oncology Clinic.

CONTEXT: Pediatric palliative care (PPC) improves end-of-life (EOL) outcomes for children with cancer. Though PPC visits are the 'intervention' in studies focused on EOL care, the content of PPC visits within pediatric oncology is poorly understood. OBJECTIVES: This study aimed to understand the scope of PPC practice during visits for children with cancer and their families. METHODS: This was a retrospective cohort study of patients 0-27 years with cancer seen in PPC clinic within an academic pediatric oncology center between 2017 and 2022. During each PPC visit, documenting providers chose the domains discussed or managed (goals of care, symptom management, and care coordination with respective subdomains). Data was abstracted from the electronic health record, PPC clinic database, and Cancer Registry. The differences in frequency and addressed domains were analyzed by demographics, visit type, diagnosis group, and proximity to EOL. RESULTS: Across 351 patients, 1919 outpatient PPC visits occurred. Median domains were higher in visits <90 days vs. 91+ days from EOL (12.0 vs. 10.0; p < 0.0001); pain and hospice collaboration were particularly discussed closer to EOL. Psychological symptoms like anxiety (30.7% vs. 21.1%; p < 0.001) were addressed more in follow-ups than initial visits. Compared to brain tumor or leukemia/lymphoma visits, solid tumor visits addressed more symptom management subdomains, especially pain (79.9%; p < 0.0001). CONCLUSION: The scope of PPC practice is broad and varied. Each visit encompasses many subdomains, the most common being care coordination with oncology teams and helping patients/families cope with the disease. More domains were addressed in solid tumor visits and near EOL.

A Pilot of a Telehealth-Hospice Transition Intervention for Children and Young Adults with Cancer.

BACKGROUND AND AIMS: Telehealth can improve care for patients with progressive cancer enrolling in hospice. Coordinated telehealth visits (patient/family-hospital-hospice) may improve communication, satisfaction with and interdisciplinary hospice collaboration. This pilot examines the impact of three coordinated telehealth visits on these outcomes. METHODS: This is a prospective pilot study of 0-29-year-old patients with cancer initiating hospice care between 2021-2023. Adult patients, caregivers, oncology and palliative care clinicians, hospice nurses and administrators were surveyed about feasibility and acceptability with telehealth (Technology Acceptance Model 2) after first and third telehealth visits. Hospice satisfaction (Consumer Assessment of Healthcare Providers and Systems) was completed by caregivers after visit 3 and during bereavement. Healthcare professionals completed the Assessment of Interprofessional Team Collaboration Scale II (AITCS-II). Survey responses were summarized and differences in scores were analyzed. RESULTS: Of 40 eligible patients, 24 enrolled, 19 completed visit 1, and 13 completed visit 3. Fourteen caregivers and two adult patients completed visit 1 surveys; nine caregivers and two adult patients completed visit 3 surveys. Participants highly rated telehealth acceptability after visit 1 (Median: 4.5, IQR: 4.0-4.7) and 3 (Median: 4.4, IQR: 4.0-4.7). Hospice services were rated as highly satisfactory at visit 3 (Median: 4.0, IQR: 3.7-4.0) and during bereavement (Median: 3.7, IQR: 3.5-4.0). Healthcare professionals (n = 85 surveys) reported excellent interprofessional collaboration (Hospital clinicians median: 99/115 and hospice teams 111/115). CONCLUSIONS: Participants found coordinated telehealth visits to be feasible, acceptable, and satisfactory. Telehealth may be utilized as an acceptable alternative to clinic visits and fosters hospital-hospice collaboration.

Malnutrition care in hospitalized pediatric inpatients: comparison of perceptions and experiences across two pediatric academic health sciences centres.

Malnutrition affects up to one in three Canadian children admitted to hospital. Awareness among pediatric healthcare providers (HCPs) of the prevalence and impacts of hospitalized malnutrition is critical for optimal management. The purpose of this study was to determine perceptions of malnutrition among pediatric HCP across two major academic health sciences centres, and to determine how the use of a standardized pediatric nutritional screening tool at one institution affects responses. Between 2020 and 2022, 192 HCPs representing nursing, dietetics, medicine, and other allied health were surveyed across McMaster Children's Hospital and The Hospital for Sick Children. 38% of respondents from both centres perceived rates of malnutrition between approximately one in three patients. Perceptions of the need for nutritional screening, assessment, and management were similar between centres. All respondents identified the need for better communication of hospitalized malnutrition status to community providers at discharge, and resource limitations affecting nutritional management of pediatric inpatients. This study represents the largest and most diverse survey of inpatient pediatric HCPs to date. We demonstrate high rates of baseline knowledge of hospital malnutrition, ongoing resource challenges, and the need for a systematic approach to pediatric nutritional management.

Systems-wide analysis and engineering of metabolic pathway fluxes in bio-succinate producing Basfia succiniciproducens.

Basfia succiniciproducens has been recently isolated as novel producer for succinate, an important platform chemical. In batch culture, the wild type exhibited a high natural yield of 0.75 mol succinate (mol glucose)⁻¹. Systems-wide ¹³C metabolic flux analysis identified undesired fluxes through pyruvate-formate lyase (PflD) and lactate dehydrogenase (LdhA). The double deletion strain B. succiniciproducens ΔldhA ΔpflD revealed a 45% improved product yield of 1.08 mol mol⁻¹. In addition, metabolic flux analysis unraveled the parallel in vivo activity of the oxidative and reductive branch of the TCA cycle in B. succiniciproducens, whereby the oxidative part mainly served for anabolism. The wild type re-directed surplus NADH via a cycle involving malic enzyme or via transhydrogenase, respectively, to supply NADPH for anabolism, because the fluxes through the oxidative PPP and isocitrate dehydrogenase, that also provide this cofactor, were not sufficient. This was not observed for the deletion mutants, B. succiniciproducens ΔpflD and ΔldhA ΔpflD, where PPP and isocitrate dehydrogenase flux alone matched with the reduced anabolic NADPH demand. The integration of the production performance into the theoretical flux space, computed by elementary flux mode analysis, revealed that B. succiniciproducens ΔldhA ΔpflD reached 62% of the theoretical maximum yield.

Sampling of Human Microbiomes to Screen for Antibiotic-Producing Commensals.

Soil-derived microorganisms have been sampled intensively throughout the last decades in order to discover bacterial strains that produce new antibiotics. The increasing emergence of multidrug-resistant bacteria and the constant high demand for new antibiotic classes are leading to the sampling and investigation of new microbiomes that contain antimicrobial producers. Human-associated microbiomes are therefore gaining more and more attention. This chapter presents a detailed description of how human microbiomes can be sampled and how microbiota members from skin and nasal samples can be isolated. Different methods for antimicrobial compound screening are presented.