Explore the vast range of titles available.

Fusobacterium nucleatum is overrepresented in the colon microbiome of colorectal cancer patients and has been associated with tumor growth enhancement and metastasis. A pivotal pathogenic factor, the autotransporter adhesin Fap2, facilitates association to cancer and immune cells via the receptors Gal-GalNAc and TIGIT, respectively, leading to deactivation of immune cells. Mechanistic details of the Fap2/TIGIT interaction remain elusive as no structural data are available. Here, we report a system to recombinantly express functional Fap2 on the Escherichia coli surface, which interacts with Gal-GalNAc on cancer cells and with purified TIGIT with submicromolar affinity. Cryo-EM structures of Fap2, alone and in complex with TIGIT, show that the elongated ~50 nm long Fap2 extracellular region binds to TIGIT on its membrane-distal tip via an extension of a β-helix domain. Moreover, by combining structure predictions, cryo-EM, docking and molecular dynamics simulations, we identified a binding pit for Gal-GalNAc on the tip of Fap2. Fusobacterium nucleatum promotes colorectal cancer via its adhesin Fap2. Here, Schöpf et al. show the molecular basis for Fap2 interaction with its receptors TIGIT on immune cells and Gal-GalNAc on tumor cells using cryo-EM and integrative modeling.

Previous studies have shown that intravenous ceftriaxone or meropenem for 14 days, followed by oral trimethoprim–sulfamethoxazole for 1 year, cures 98% of people with Whipple's disease. However, intravenous therapy requires hospitalisation and carries risks for treatment-associated complications. The aim of this study was to investigate whether oral-only treatment for Whipple's disease is non-inferior to intravenous therapy. This phase 2/3, prospective, open-label, randomised, controlled, non-inferiority trial enrolled individuals aged 18 years or older with confirmed Whipple's disease from across Germany who had received treatment for less than 1 month at Charité–Universitätsmedizin Berlin. Participants were randomly assigned (1:1) with block randomisation to receive either intravenous ceftriaxone (2 g once per day) for 14 days, followed by oral trimethoprim–sulfamethoxazole (960 mg twice per day) for 12 months, or oral doxycycline (100 mg twice per day) plus hydroxychloroquine (200 mg twice per day) for 12 months. Ten participants who had already received intravenous ceftriaxone were non-randomly assigned to the intravenous treatment group. Participants in the oral-only treatment group were PCR-positive for Tropheryma whipplei in cerebrospinal fluid received trimethoprim–sulfamethoxazole (960 mg five times per day) until clearance. The primary outcome was complete clinical remission without recurrence during the observation period of 24 months, assessed in the intention-to-treat (ITT) population. The prespecified non-inferiority margin was –18%. Safety was a secondary endpoint, assessed in the ITT population. The study was registered with the EU Clinical Trials Register, EudraCT 2008–003951–54, and is completed. Between May 26, 2010, and Oct 30, 2018, we screened 310 individuals and enrolled 64 participants in the study. After exclusion of four individuals whose diagnosis was not confirmed, 31 participants were assigned to the intravenous treatment group and 29 to the oral-only treatment group. By ITT, 25 (81%) of 31 participants in the intravenous treatment group and 28 (97%) of 29 participants in the oral-only treatment group had complete clinical remission without recurrence. The risk difference was 15·9 percentage points (95% CI –1·2 to 33·1), with the lower bound of the 95% CI above our non-inferiority margin of –18%. A post-hoc per-protocol analysis confirmed the non-inferiority of oral-only treatment. No participant relapsed, but two participants in the intravenous treatment group died from nosocomial infections. Serious adverse events occurred in 13 (42%) of 31 participants in the intravenous treatment group and eight (28%) of 29 participants in the oral-only treatment group, but this difference was not statistically significant (p=0·244). Oral-only treatment of Whipple's disease was safe and non-inferior to sequential intravenous–oral treatment. Oral treatment facilitates patient management and might reduce hospital-acquired treatment complications and costs. German Research Foundation and the Robert Koch Institute. For the German translation of the abstract see Supplementary Materials section.

Endoscopic lung volume reduction (ELVR) using endobronchial valves (EBV) is a treatment option for a subset of patients with severe chronic obstructive pulmonary disease (COPD), suffering from emphysema and hyperinflation. In this pilot study, we aimed to determine the presence of bacterial biofilm infections on EBV and investigate their involvement in lack of clinical benefits, worsening symptomatology, and increased exacerbations that lead to the decision to remove EBVs. We analyzed ten COPD patients with ELVR who underwent EBV removal. Clinical data were compared to the microbiological findings from conventional EBV culture. In addition, EBV were analyzed by FISHseq, a combination of Fluorescence in situ hybridization (FISH) with PCR and sequencing, for visualization and identification of microorganisms and biofilms. All ten patients presented with clinical symptoms, including pneumonia and recurrent exacerbations. Microbiological cultures from EBV detected several microorganisms in all ten patients. FISHseq showed either mixed or monospecies colonization on the EBV, including oropharyngeal bacterial flora, Staphylococcus aureus , Pseudomonas aeruginosa , Streptococcus spp., and Fusobacterium sp. On 5/10 EBV, FISHseq visualized biofilms, on 1/10 microbial microcolonies, on 3/10 single microorganisms, and on 1/10 no microorganisms. The results of the study demonstrate the presence of biofilms on EBV for the first time and its potential involvement in increased exacerbations and clinical worsening in patients with ELVR. However, further prospective studies are needed to evaluate the clinical relevance of biofilm formation on EBV and appropriate treatment options to avoid infections in patients with ELVR.

ObjectiveIn spite of the progress in antimicrobial and surgical therapy, infective endocarditis (IE) is still associated with a high morbidity and mortality. IE is characterized by bacterial biofilms of the endocardium, especially of the aortic and mitral valve leading to their destruction. About one quarter of patients with formal surgery indication cannot undergo surgery. This group of patients needs further options of therapy, but due to a lack of models for IE prospects of research are low. Therefore, the purpose of this project was to establish an in vitro model of infective endocarditis to allow growth of bacterial biofilms on porcine aortic valves, serving as baseline for further research.Methods and resultsA pulsatile two-chamber circulation model was constructed that kept native porcine aortic valves under sterile, physiologic hemodynamic and temperature conditions. To create biofilms on porcine aortic valves the system was inoculated with Staphylococcus epidermidis PIA 8400. Aortic roots were incubated in the model for increasing periods of time (24 h and 40 h) and bacterial titration (1.5 × 104 CFU/mL and 1.5 × 105 CFU/mL) with 5 L cardiac output per minute. After incubation, tissue sections were analysed by fluorescence in situ hybridization (FISH) for direct visualization of the biofilms. Pilot tests for biofilm growth showed monospecies colonization consisting of cocci with time- and inocula-dependent increase after 24 h and 40 h (n = 4). In n = 3 experiments for 24 h, with the same inocula, FISH visualized biofilms with ribosome-containing, and thus metabolic active cocci, tissue infiltration and similar colonization pattern as observed by the FISH in human IE heart valves infected by S. epidermidis.ConclusionThese results demonstrate the establishment of a novel in vitro model for bacterial biofilm growth on porcine aortic roots mimicking IE. The model will allow to identify predilection sites of valves for bacterial adhesion and biofilm growth and it may serve as baseline for further research on IE therapy and prevention, e.g. the development of antimicrobial transcatheter approaches to IE.Graphic abstract

The diagnosis of infective endocarditis (IE) remains a challenge. One of the rare bacterial species recently associated with biofilms and negative cultures in infective endocarditis is Aerococcus urinae. Whether the low number of reported cases might be due to lack of awareness and misidentification, mainly as streptococci, is currently being discussed. To verify the relevance and biofilm potential of Aerococcus in endocarditis, we used fluorescence in situ hybridization to visualize the microorganisms within the heart valve tissue. We designed and optimized a specific FISH probe (AURI) for in situ visualization and identification of A. urinae in sections of heart valves from two IE patients whose 16S rRNA gene sequencing had deteced A. urinae. Both patients had a history of urinary tract infections. FISH visualized impressive in vivo grown biofilms in IE, thus confirming the potential of A. urinae as a biofilm pathogen. In both cases, FISH/PCR was the only method to unequivocally identify A. urinae as the only causative pathogen for IE. The specific FISH assay for A. urinae is now available for further application in research and diagnostics. A. urinae should be considered in endocarditis patients with a history of urinary tract infections. These findings support the biofilm potential of A. urinae as a virulence factor and are meant to raise the awareness of this pathogen.

The natural bioactive molecule farnesol (FAR) is widely studied mainly for its antibiofilm and antimicrobial properties. In addition, it increases the effectiveness of some antimicrobial substances, which makes it interesting for the development of combined therapy. In the present work, the effect of FAR either alone or in combination with oxacillin (OXA) on mixed biofilms formed by clinically relevant pathogens, Candida albicans and Staphylococcus aureus, was studied. S. aureus isolates used for biofilm formation originated from blood cultures and central venous catheters (CVC) were characterized in terms of antimicrobial resistance. The minimal biofilm inhibitory concentration (MBIC50) for FAR of 48 h mixed biofilms formed by the C. albicans and methicillin-sensitive S. aureus (MSSA) was determined to be 125 μM, and for the mixed biofilms with methicillin-resistant S. aureus (MRSA) was determined to be 250 μM. Treatment of mixed biofilms with OXA (2 mg/mL) showed ≤4% inhibition; however, the combination of OXA (2 mg/mL) and FAR (300 μM) resulted in 80% inhibition of biofilms. In addition, planktonic cells of S. aureus exhibited an increased susceptibility to OXA, cefoxitin and kanamycin in the presence of FAR (150 and 300 μM). Scanning electron microscopy (SEM) micrographs confirmed patchy biofilm and lack of candidal hyphae in the samples treated with FAR and FAR/OXA in comparison to control and mixed biofilms treated only with OXA. Intriguingly, in a pilot experiment using fluorescence in situ hybridization (FISH), considerable differences in activity (as indicated by ribosome content) of staphylococcal cells were detected. While the activity rate of the staphylococci in mixed biofilms treated with FAR was high, no FISH-positive signal for staphylococcal cells was found in the biofilm treated with FAR/OXA.

To explore the effects of abdominal surgery and interleukin-1 signaling on antimicrobial defense in a model of postoperative ileus. C57BL/6 and Interleukin-1 receptor type I (IL-1R1) deficient mice underwent intestinal manipulation to induce POI. Expression of mucosal IL-1α, IL-1β and IL-1R1 and several antimicrobial peptides and enzymes were measured by quantitative PCR or ELISA, western blotting or immunohistochemistry. Bacterial overgrowth was determined by fluorescent in-situ hybridization and counting of jejunal luminal bacteria. Translocation of aerobic and anaerobic bacteria into the intestinal wall, mesenteric lymph nodes, liver and spleen was determined by counting bacterial colonies on agar plates 48h after plating of tissue homogenates. Antimicrobial activity against E. coli and B. vulgatus was analyzed in total and cationic fractions of small bowel mucosal tissue homogenates by a flow cytometry-based bacterial depolarization assay. Jejunal bacterial overgrowth was detected 24h after surgery. At the same time point, but not in the early phase 3h after surgery, bacterial translocation into the liver and mesenteric lymph nodes was observed. Increased antimicrobial activity against E. coli was induced within early phase of POI. Basal antimicrobial peptide and enzyme gene expression was higher in the ileal compared to the jejunal mucosa. The expression of lysozyme 1, cryptdin 1, cryptdin 4 and mucin 2 were reduced 24h after surgery in the ileal mucosa and mucin 2 was also reduced in the jejunum. Postoperative IL-1α and IL-1β were increased in the postoperative mucosa. Deficiency of IL-1R1 affected the expression of antimicrobial peptides during homeostasis and POI. Small bowel antimicrobial capacity is disturbed during POI which is accompanied by bacterial overgrowth and translocation. IL-1R1 is partially involved in the gene expression of mucosal antimicrobial peptides. Altered small bowel antimicrobial activity may contribute also to POI development and manifestation in patients undergoing abdominal surgery.

(1) Background: The successful treatment of infective endocarditis (IE) relies on detecting causative pathogens to administer targeted antibiotic therapy. In addition to standard microbiological cultivation of pathogens from tissue obtained during heart valve surgery, the potential of molecular biological methods was evaluated. (2) Methods: A retrospective study was performed on heart valve tissue from 207 patients who underwent heart valve surgery for IE. FISHseq (fluorescence in situ hybridization combined with 16S rRNA gene PCR and sequencing) was performed in addition to conventional culture-based microbiological diagnostics. The diagnostic performance of FISHseq was compared with the conventional methods and evaluated in the clinical context. (3) Results: Overall, FISHseq provided a significantly higher rate of specific pathogen detection than conventional valve culture (68.1% vs. 33.3%, p < 0.001). By complementing the findings from blood culture and valve culture, FISHseq was able to provide a new microbiological diagnosis in 10% of cases, confirm the cultural findings in 24.2% of cases and provide greater diagnostic accuracy in 27.5% of cases. FISHseq could identify a pathogen in blood-culture-negative IE in 46.2% of cases, while valve culture provided only 13.5% positive results (p < 0.001). (4) Conclusions: This study demonstrates that using FISHseq as an additional molecular biological technique for diagnostics in IE adds substantial diagnostic value, with potential implications for the treatment of IE. It provides pathogen detection, especially in cases where conventional microbiological cultivation is negative or inconclusive.

The polymicrobial nature of periodontal diseases is reflected by the diversity of phylotypes detected in subgingival plaque and the finding that consortia of suspected pathogens rather than single species are associated with disease development. A number of these microorganisms have been demonstrated in vitro to interact and enhance biofilm integration, survival or even pathogenic features. To examine the in vivo relevance of these proposed interactions, we extended the spatial arrangement analysis tool of the software daime (digital image analysis in microbial ecology). This modification enabled the quantitative analysis of microbial co-localization in images of subgingival biofilm species, where the biomass was confined to fractions of the whole-image area, a situation common for medical samples. Selected representatives of the disease-associated red and orange complexes that were previously suggested to interact with each other in vitro (Tannerella forsythia with Fusobacterium nucleatum and Porphyromonas gingivalis with Prevotella intermedia) were chosen for analysis and labeled with specific fluorescent probes via fluorescence in situ hybridization. Pair cross-correlation analysis of in vivo grown biofilms revealed tight clustering of F. nucleatum/periodonticum and T. forsythia at short distances (up to 6 µm) with a pronounced peak at 1.5 µm. While these results confirmed previous in vitro observations for F. nucleatum and T. forsythia, random spatial distribution was detected between P. gingivalis and P. intermedia in the in vivo samples. In conclusion, we successfully employed spatial arrangement analysis on the single cell level in clinically relevant medical samples and demonstrated the utility of this approach for the in vivo validation of in vitro observations by analyzing statistically relevant numbers of different patients. More importantly, the culture-independent nature of this approach enables similar quantitative analyses for \"as-yet-uncultured\" phylotypes which cannot be characterized in vitro.

An 8-year-old male Rhodesian Ridgeback was presented with fever and severe thrombocytopenia. Clinical and laboratory examination, echocardiography, blood culture, and pathohistology revealed evidence of infective endocarditis, ischemic renal infarcts, and septic encephalitis. Treatment was started immediately but the dog’s condition worsened, and the dog had to be euthanized. The causative Streptococcus canis strain was detected by blood culture and MALDI-TOF MS and analyzed using whole-genome sequencing and multilocus sequence typing. Antibiotic susceptibility testing did not detect any resistance. The affected heart valve was analyzed using FISH imaging, which showed a streptococcal biofilm on the heart valve. Bacteria in biofilms are recalcitrant to antibiotic treatment. Early diagnosis could be beneficial to treatment outcome. Treatment of endocarditis could be improved by researching the optimal dosage of antibiotics in conjunction with the use of biofilm-active drugs.