Distribution, organization and expression of genes concerned with anaerobic lactate utilization in human intestinal bacteria

Lactate accumulation in the human gut is linked to a range of deleterious health impacts. However, lactate is consumed and converted to the beneficial short-chain fatty acids butyrate and propionate by indigenous lactate-utilizing bacteria. To better understand the underlying genetic basis for lactate utilization, transcriptomic analyses were performed for two prominent lactate-utilizing species from the human gut, Anaerobutyricum soehngenii and Coprococcus catus , during growth on lactate, hexose sugar or hexose plus lactate. In A. soehngenii L2-7 six genes of the lactate utilization (lct) cluster, including NAD-independent d-lactate dehydrogenase (d-iLDH), were co-ordinately upregulated during growth on equimolar d- and l-lactate (dl-lactate). Upregulated genes included an acyl-CoA dehydrogenase related to butyryl-CoA dehydrogenase, which may play a role in transferring reducing equivalents between reduction of crotonyl-CoA and oxidation of lactate. Genes upregulated in C. catus GD/7 included a six-gene cluster (lap) encoding propionyl CoA-transferase, a putative lactoyl-CoA epimerase, lactoyl-CoA dehydratase and lactate permease, and two unlinked acyl-CoA dehydrogenase genes that are candidates for acryloyl-CoA reductase. A d-iLDH homologue in C. catus is encoded by a separate, partial lct, gene cluster, but not upregulated on lactate. While C. catus converts three mols of dl-lactate via the acrylate pathway to two mols propionate and one mol acetate, some of the acetate can be re-used with additional lactate to produce butyrate. A key regulatory difference is that while glucose partially repressed lct cluster expression in A. soehngenii , there was no repression of lactate-utilization genes by fructose in the non-glucose utilizer C. catus . This suggests that these species could occupy different ecological niches for lactate utilization in the gut, which may be important factors to consider when developing lactate-utilizing bacteria as novel candidate probiotics

Real-time in vivo imaging of invasive- and biomaterial-associated bacterial infections using fluorescently labelled vancomycin

Invasive and biomaterial-associated infections in humans are often difficult to diagnose and treat. Here, guided by recent advances in clinically relevant optical imaging technologies, we explore the use of fluorescently labelled vancomycin (vanco-800CW) to specifically target and detect infections caused by Gram-positive bacteria. The application potential of vanco-800CW for real-time in vivo imaging of bacterial infections is assessed in a mouse myositis model and a human post-mortem implant model. We show that vanco-800CW can specifically detect Gram-positive bacterial infections in our mouse myositis model, discriminate bacterial infections from sterile inflammation in vivo and detect biomaterial-associated infections in the lower leg of a human cadaver. We conclude that vanco-800CW has a high potential for enhanced non-invasive diagnosis of infections with Gram-positive bacteria and is a promising candidate for early-phase clinical trials

The transition between sessile and motile bacterial lifestyles

Nader inzicht in effectiviteit Staphylococcus aureus Eleni Tsompanidou verrichtte onderzoek naar de mechanismen die de verspreiding van de Staphylococcus aureus verklaren. Ze ontdekte dat alleen stammen van S. aureus met een actief agr-regulatiesysteem zich goed kunnen verspreiden over oppervlakken. De bacterie S. aureus is een van de belangrijkste veroorzakers van ziekenhuisinfecties. Deze infecties zijn vaak moeilijk te bestrijden. Meer dan twintig procent van de gezonde mensen draagt de bacterie met zich mee, onder meer in de neus en op de huid. Dit is ongevaarlijk. Wanneer echter de natuurlijke barrières van het lichaam, bijvoorbeeld door een operatie, doorbroken worden, kan de bacterie het immuunsysteem ontwijken en een infectie veroorzaken. Zo'n infectie kan levensbedreigend zijn. Tsompanidou verrichtte onderzoek naar de mechanismen die de verspreiding van de S. aureus verklaren. Ze ontdekte dat alleen stammen van S. aureus met een actief agr-regulatiesysteem zich goed kunnen verspreiden over oppervlakken. Het agr-systeem reguleert de expressie van ziekmakende virulentiefactoren. Stammen met een inactief agr-regulatiesysteem kunnen zich niet verspreiden, zo stelt Tsompanidou vast. Dit blijkt een indirect effect te zijn van de regulatie van surfactante peptiden (phenol-soluble modulins, PSMs) via het agr-systeem. Tsompanidou concludeert dat het agr-systeem en de regulatie van PSMs een cruciale rol spelen bij de verspreiding van S. aureus. Deze inzichten kunnen wellicht helpen de bacterie effectiever te bestrijden. Staphylococcus aureus is one of the five most common causative agents of nosocomial infections. This bacterium is notorious for causing post-surgical wound infections, and chronic infections due to the formation of biofilms on indwelling medical devices . Pathogenic bacteria, such as S. aureus, utilize many different mechanisms to escape the host immune defenses, to establish themselves on the site of infection, and to invade different niches in order to find new sources of nutrients. The research presented in this thesis was specifically focused on two of these mechanisms, namely surface translocation and biofilm formation. Specifically, it was observed that only strains with an active agr locus can spread, whereas strains where the agr locus remains silent are unable to spread. Further analyses revealed that the agr-regulated phenol-soluble modulins (PSMs) are promoting colony spreading of S. aureus on wet surfaces. Interestingly, PSMs also promote detachment of S. aureus cells from a biofilm. Moreover, cell-wall associated proteins with known roles in biofilm formation were found to be limiting factors for staphylococcal spreading over wet surfaces. Together, the present data imply that biofilm formation and spreading are opposing processes that define the sessile and motile lifestyles of staphylococci. Interestingly, community-acquired methicillin resistant S. aureus (MRSA) strains, which are highly capable of infecting healthy individuals outside healthcare settings, display high expression levels of agr and therefore also of PSMs. The present observations indicate that a combination of different approaches may be needed to successfully combat both the sessile and motile forms of S. aureus.

Phenol-soluble modulins, hellhounds from the staphylococcal virulence-factor pandemonium

<p>Phenol-soluble modulins are secreted peptides with multiple functions in Staphylococcus aureus pathogenesis and spreading. Recent studies by Otto and co-workers show that these hellhounds of the staphylococcal virulence-factor pandemonium are unleashed through an essential ABC transporter, which represents an exciting new target for stopping the spread of this important pathogen.</p>

The sortase A substrates FnbpA, FnbpB, ClfA and ClfB antagonize colony spreading of staphylococcus aureus

Staphylococcus aureus is an important human pathogen that is renowned both for its rapid transmission within hospitals and the community, and for the formation of antibiotic resistant biofilms on medical implants. Recently, it was shown that S. aureus is able to spread over wet surfaces. This motility phenomenon is promoted by the surfactant properties of secreted phenol-soluble modulins (PSMs), which are also known to inhibit biofilm formation. The aim of the present studies was to determine whether any cell surface-associated S. aureus proteins have an impact on colony spreading. To this end, we analyzed the spreading capabilities of strains lacking non-essential components of the protein export and sorting machinery. Interestingly, our analyses reveal that the absence of sortase A (SrtA) causes a hyper-spreading phenotype. SrtA is responsible for covalent anchoring of various proteins to the staphylococcal cell wall. Accordingly, we show that the hyper-spreading phenotype of srtA mutant cells is an indirect effect that relates to the sortase substrates FnbpA, FnbpB, ClfA and ClfB. These surface-exposed staphylococcal proteins are known to promote biofilm formation, and cell-cell interactions. The hyper-spreading phenotype of srtA mutant staphylococcal cells was subsequently validated in Staphylococcus epidermidis. We conclude that cell wall-associated factors that promote a sessile lifestyle of S. aureus and S. epidermidis antagonize the colony spreading motility of these bacteria

Deliverable 9.6: Intermediate report after one year of measurement

The present document is the Deliverable D9.6 “Intermediate report after one year of measurement”. The document describes the work carried out within the task 9.5 entitled “Overall evaluation and impact analysis for impact enhancement”. The focus of this task is to provide intermediate results of the demonstration activities in the three Lighthouse (LH) cities and to present the data currently transferred to the IRIS Key Performance Indicators (KPI) tool. The deliverable D9.6 is based on the work done in the Work Package (WP) 9, in particular the work in task 9.4 and task 9.5 (presented previously in D9.4 and D9.5). In this deliverable, the monitoring framework and established baselines developed in D9.5 are used to collect the data needed for the calculation of the KPIs. The KPIs are in turn used to evaluate the outcome and impact of the implemented measures. The collected data is transferred to the KPI tool, which was created and presented in D9.4. The tool processes and calculates the KPIs and visualizes the results. Data can be transferred to the KPI tool automatically, through a CIP, or manually through a template. A process which is described in this deliverable. This deliverable was intended to be an intermediate report to provide an initial insight to the results for all measures in the IRIS project. However, due to the lack of data from measures, which in part is due to the Covid-19 pandemic, this report focuses more on providing information about the process of collecting data and transferring it into the KPI tool. This process is collaborative and has been carried out within the IRIS LH cites with support from the technical partners and the WP9 team. Complexity of APIs and the lack of standards have made data extraction and transfer into the KPI tool more difficult. Furthermore, not all measures in IRIS are connected to CIP which means that manual data collection was required and a systematic procedure for this collection needed to be developed and introduced to the partners. There are several different reasons for lack of data and the resulting exclusion of some measures from this deliverable. A few measures are not yet in operation, while for other data collection have not started or the data transfer to the KPI tool has not been established yet. However, the work done in task 9.5 has provided new knowledge on issues and errors that can occur in the process of transferring data and establishing KPIs. Through dialogues with the project partners, the need to clarify some KPI cards with i.e. units, formulas or use cases has been highlighted. The close cooperation with the project partners has led to continued work on the definitions of the KPIs and what KPIs to include, taking steps in the direction of clearer interpretation and more consistent use. Further adaptation of several KPI-cards was done by the WP9 team. In the process of adjusting KPIs, the effect these adjustments would have on all measures that use them were considered. The process of developing KPIs involves a balance between finding indicators that can be used more generally and indicators that are more specific and thus better capture the purpose of a specific measure. The improvements of KPIs and lessons learned in task 9.5 will be of great use in the continued work of WP9. Focus will be on transfer of data from all measures into the KPI tool. A continuous dialogue with responsible project partners to ensure this data transfer and discussions on deviation and errors in the initial results will be established.Horizon 2020Grants Agreement No 774199IRIS Integrated and Replicable Solutions for Co-Creation in Sustainable Citie

Deliverable 9.6: Intermediate report after one year of measurement

The present document is the Deliverable D9.6 “Intermediate report after one year of measurement”. The document describes the work carried out within the task 9.5 entitled “Overall evaluation and impact analysis for impact enhancement”. The focus of this task is to provide intermediate results of the demonstration activities in the three Lighthouse (LH) cities and to present the data currently transferred to the IRIS Key Performance Indicators (KPI) tool. The deliverable D9.6 is based on the work done in the Work Package (WP) 9, in particular the work in task 9.4 and task 9.5 (presented previously in D9.4 and D9.5). In this deliverable, the monitoring framework and established baselines developed in D9.5 are used to collect the data needed for the calculation of the KPIs. The KPIs are in turn used to evaluate the outcome and impact of the implemented measures. The collected data is transferred to the KPI tool, which was created and presented in D9.4. The tool processes and calculates the KPIs and visualizes the results. Data can be transferred to the KPI tool automatically, through a CIP, or manually through a template. A process which is described in this deliverable. This deliverable was intended to be an intermediate report to provide an initial insight to the results for all measures in the IRIS project. However, due to the lack of data from measures, which in part is due to the Covid-19 pandemic, this report focuses more on providing information about the process of collecting data and transferring it into the KPI tool. This process is collaborative and has been carried out within the IRIS LH cites with support from the technical partners and the WP9 team. Complexity of APIs and the lack of standards have made data extraction and transfer into the KPI tool more difficult. Furthermore, not all measures in IRIS are connected to CIP which means that manual data collection was required and a systematic procedure for this collection needed to be developed and introduced to the partners. There are several different reasons for lack of data and the resulting exclusion of some measures from this deliverable. A few measures are not yet in operation, while for other data collection have not started or the data transfer to the KPI tool has not been established yet. However, the work done in task 9.5 has provided new knowledge on issues and errors that can occur in the process of transferring data and establishing KPIs. Through dialogues with the project partners, the need to clarify some KPI cards with i.e. units, formulas or use cases has been highlighted. The close cooperation with the project partners has led to continued work on the definitions of the KPIs and what KPIs to include, taking steps in the direction of clearer interpretation and more consistent use. Further adaptation of several KPI-cards was done by the WP9 team. In the process of adjusting KPIs, the effect these adjustments would have on all measures that use them were considered. The process of developing KPIs involves a balance between finding indicators that can be used more generally and indicators that are more specific and thus better capture the purpose of a specific measure. The improvements of KPIs and lessons learned in task 9.5 will be of great use in the continued work of WP9. Focus will be on transfer of data from all measures into the KPI tool. A continuous dialogue with responsible project partners to ensure this data transfer and discussions on deviation and errors in the initial results will be established.Horizon 2020Grants Agreement No 774199IRIS Integrated and Replicable Solutions for Co-Creation in Sustainable Citie