Mucosal-associated invariant T cells from Clostridioides difficile-infected patients exhibit a distinct proinflammatory phenotype and enhanced cytotoxic activity.

Mucosal-associated invariant T (MAIT) cells are innate-like T cells mainly found in the mucosa and peripheral blood. We have recently demonstrated that Clostridioides difficile activates MAIT cells in vitro. However, their role in the pathogenesis of C. difficile infection (CDI) in human patients remains elusive to date. In this study, we performed comprehensive immunophenotyping of MAIT cells derived from CDI patients and compared their phenotype to that of patients with inflammatory bowel diseases (IBD) and healthy controls. Our study revealed that blood MAIT cells from CDI patients exhibit an interleukin 17a (IL-17a)-dominated proinflammatory phenotype and an increased readiness to synthesize the proinflammatory cytokine interferon γ (IFN-γ) following in vitro re-stimulation. Moreover, the cytotoxic activity of MAIT cells, as measured by surface CD107a and intracellular granzyme B expression, was strongly increased in CDI. Multi epitope ligand cartography (MELC) analysis of intestinal biopsies from CDI patients revealed that MAIT cells exhibit an increased production of granzyme B and increased cytotoxicity compared to the control group. Together with previously published in vitro data from our group, our findings suggest that MAIT cells are functionally involved in the immune response against C. difficile and contribute to the pathogenesis of CDI.

Previous antibiotic therapy as independent risk factor for the presence of vancomycin-resistant enterococci in surgical inpatients. Results from a matched case-control study.

BACKGROUND: Investigation of risk factors for the presence of vancomycin-resistant enterococci (VRE) in inpatients on surgical wards and associated intensive care units of a German tertiary care hospital. METHODS: A single-centre retrospective matched case-control study was performed with surgical inpatients admitted between July 2013 and December 2016. Patients with in-hospital detection of VRE later than 48 h after admission were included and comprised 116 VRE-positive cases and 116 VRE-negative matched controls. VRE isolates of cases were typed by multi-locus sequence typing. RESULTS: ST117 was identified as the dominant VRE sequence type. Next to length of stay in hospital or on an intensive care unit and previous dialysis the case-control study revealed previous antibiotic therapy as a risk factor for the in-hospital detection of VRE. The antibiotics piperacillin/tazobactam, meropenem, and vancomycin were associated with the highest risks. After taking into account length of stay in hospital as possible confounder other potential contact-related risk factors such as previous sonography, radiology, central venous catheter, and endoscopy were not significant. CONCLUSIONS: Previous dialysis and previous antibiotic therapy were identified as independent risk factors for the presence of VRE in surgical inpatients.

C9 immunostaining as a tissue biomarker for periprosthetic joint infection diagnosis.

Background: Culture-negative periprosthetic joint infections (PJI) are often false diagnosed as aseptic implant failure leading to unnecessary revision surgeries due to repeated infections. A marker to increase the security of e PJI diagnosis is therefore of great importance. The aim of this study was to test C9 immunostaining of periprosthetic tissue as a novel tissue-biomarker for a more reliable identification of PJI, as well as potential cross-reactivity. Method: We included 98 patients in this study undergoing septic or aseptic revision surgeries. Standard microbiological diagnosis was performed in all cases for classification of patients. Serum parameters including C-reactive protein (CRP) serum levels and white blood cell (WBC) count were included, and the periprosthetic tissue was immunostained for C9 presence. The amount of C9 tissue staining was evaluated in septic versus aseptic tissue and the amount of C9 staining was correlated with the different pathogens causing the infection. To exclude cross-reactions between C9 immunostaining and other inflammatory joint conditions, we included tissue samples of a separate cohort with rheumatoid arthritis, wear particles and chondrocalcinosis. Results: The microbiological diagnosis detected PJI in 58 patients; the remaining 40 patients were classified as aseptic. Serum CRP values were significantly increased in the PJI cohort. Serum WBC was not different between septic and aseptic cases. We found a significant increase in C9 immunostaining in the PJI periprosthetic tissue. To test the predictive value of C9 as biomarker for PJI we performed a ROC analyses. According to the Youden's criteria C9 is a very good biomarker for PJI detection with a sensitivity of 89% and a specificity of 75% and an AUC of 0.84. We did not observe a correlation of C9 staining with the pathogen causing the PJI. However, we observed a cross reactivity with the inflammatory joint disease like rheumatoid arthritis and different metal wear types. In addition, we did not observe a cross reactivity with chondrocalcinosis. Conclusion: Our study identifies C9 as a potential tissue-biomarker for the identification of PJI using immunohistological staining of tissue biopsies. The use of C9 staining could help to reduce the number of false negative diagnoses of PJI.

Molecular characterization of Arcobacter butzleri isolates from poultry in rural Ghana.

In recent years, Arcobacter butzleri has gained clinical significance as an emerging diarrheagenic pathogen associated with poultry and water reservoirs. The full clinical significance of Arcobacter remains rather speculative due to variable virulence and antibiotic susceptibility of individual strains. The aims of the present study were (i) to identify antibiotic resistance genes (ARGs) in the genome sequences of two multidrug-resistant A. butzleri isolates, (ii) to use multilocus-sequence typing (MLST) to generate a guiding phylogeny of A. butzleri isolates collected in Kumasi, Ghana, (iii) to examine the distribution of ARGs in the test cohort, and (iv) to assess the strain's virulence and possible antibiotic treatment options for arcobacteriosis based on the genome sequences and the ARG distribution. A total of 48 A. butzleri isolates obtained from poultry were included in the analysis. These isolates were genotyped by MLST and the antibiotic susceptibilities of isolates to ampicillin, ciprofloxacin, tetracycline, gentamicin, and erythromycin were tested by disk diffusion. Whole genome sequence data of two multidrug-resistant (MDR) A. butzleri isolates were obtained by a combination of single-molecule real-time (SMRT) and Illumina sequencing technology. A total of 14 ARGs were identified in the two generated genome sequences. For all 48 isolates, the frequency of these 14 ARGs was investigated by PCR or amplicon sequencing. With 44 different sequence types found among 48 isolates, strains were phylogenetically heterogeneous. Four of 48 isolates showed an ARG constellation indicating a multidrug-resistant phenotype. The virulence genes in the two A. butzleri genomes showed that the species might be characterized by a somewhat lower virulence as Campylobacter species. The phenotypic susceptibility data combined with the distribution of the particular ARGs especially oxa-464 and the T81I point mutation of the quinolone resistance determining region (QRDR) in a significant percentage of isolates indicated that macrolides and tetracycline can be recommended for calculated antibiotic treatment of arcobacteriosis in Ghana, but not ampicillin and quinolones.

IL-13 determines specific IgE responses and SARS-CoV-2 immunity after mild COVID-19 and novel mRNA vaccination.

After recovery, mild and severe COVID-19 diseases are associated with long-term effects on the host immune system, such as prolonged T-cell activation or accumulation of autoantibodies. In this study, we show that mild SARS-CoV-2 infections, but not SARS-CoV-2 spike mRNA vaccinations, cause durable atopic risk factors such as a systemic Th2- and Th17-type environment as well as activation of B cells responsive of IgE against aeroallergens from house dust mite and mold. At an average of 100 days post mild SARS-CoV-2 infections, anti-mold responses were associated with low IL-13 levels and increased pro-inflammatory IL-6 titers. Acutely severely ill COVID-19 patients instead showed no evidence of atopic reactions. Considering convalescents of mild COVID-19 courses and mRNA-vaccinated individuals together, IL-13 was the predominant significantly upregulated factor, likely shaping SARS-CoV-2 immunity. Application of multiple regression analysis revealed that the IL-13 levels of both groups were determined by the Th17-type cytokines IL-17A and IL-22. Taken together, these results implicate a critical role for IL-13 in the aftermath of SARS-CoV-2 mild infections and mRNA vaccinations, conferring protection against airway directed, atopic side reactions that occur in mildly experienced COVID-19.

Klebsiella oxytoca causes colonization resistance against multidrug-resistant K. pneumoniae in the gut via cooperative carbohydrate competition.

Gut colonization with multidrug-resistant (MDR) bacteria enhances the risk of bloodstream infections in susceptible individuals. We demonstrate highly variable degrees of ex vivo colonization resistance against a carbapenem-resistant Klebsiella pneumoniae strain in human feces samples and subsequently isolate diverse K. oxytoca strains from protected donors. Several of these K. oxytoca strains reduce gut colonization of MDR K. pneumoniae strains in antibiotic-treated and gnotobiotic mouse models. Comparative analysis of K. oxytoca strains coupled with CRISPR-Cas9-mediated deletion of casA, a protein essential for utilization of selected beta-glucosides, identified competition for specific carbohydrates as key in promoting colonization resistance. In addition to direct competition between K. oxytoca and K. pneumoniae, cooperation with additional commensals is required to reestablish full colonization resistance and gut decolonization. Finally, humanized microbiota mice generated from K. pneumoniae-susceptible donors are protected by K. oxytoca administration, demonstrating the potential of commensal K. oxytoca strains as next-generation probiotics.

A combined oro-nasopharyngeal swab is more sensitive than mouthwash in detecting SARS-CoV-2 by a high-throughput PCR assay.

OBJECTIVES: The optimal diagnostic specimen to detect SARS-CoV-2 by PCR in the upper respiratory tract is unclear. Mouthwash fluid has been reported as an alternative to nasopharyngeal and oropharyngeal swabs. We compared mouthwash fluid with a combined oro-nasopharyngeal swab regarding test performance. METHODS: In a large refugee facility, we retested individuals with a previous positive test for SARS-CoV-2 and their quarantined close contacts. All individuals were asymptomatic at the time of testing. First, a mouthwash (gargling for at least 5 s) with sterile water was performed. Then, with a single flocked swab the back of the throat and subsequently the nasopharynx were sampled. Samples were inactivated and analysed on a Roche cobas 6800® system with the Roche SARS-CoV-2 test. RESULTS: Of 76 individuals, 39 (51%) tested positive for SARS-CoV-2 by oro-nasopharyngeal swab. Mouthwash detected 13 of 76 (17%) infections, but did not detect any additional infection. Samples that were positive in both tests, had lower cycle threshold (Ct)-values for oro-nasopharyngeal samples, indicating a higher virus concentration, compared to samples only positive in oro-nasopharyngeal swabs. CONCLUSION: Mouthwash is not as sensitive as combined oro-nasopharyngeal swab in detecting upper respiratory tract infection.

CSF Neurofilament light chain level predicts axonal damage in cerebral vasculitis.

The rarity of primary angiitis of the central nervous system (PACNS) demands diagnostic and prognostic biomarkers. We retrospectively measured Neurofilament light chain (NFL) concentrations in cerebrospinal fluid in a severely relapsing PACNS patient at multiple time points during the course of the disease. A marked increase in NFL levels preceding the onset of neuro-axonal damage and arterial-vessel abnormalities was observed with magnetic resonance imaging as well as with MR- and conventional angiography. Thus, marked elevation of NFL in PACNS seems to occur ahead of definitive radiological abnormalities and might serve as a diagnostic biomarker.

The terminal complement pathway is activated in septic but not in aseptic shoulder revision arthroplasties.

BACKGROUND: The early diagnosis of suspected periprosthetic low-grade infections in shoulder arthroplasties is important for the outcome of the revision surgical procedures. The aim of this study was to investigate new biomarkers of infection in revision shoulder arthroplasties, taking into account the implant design, patient age, and comorbidities. METHODS: The study included 33 patients with shoulder arthroplasties undergoing revision surgical procedures. Microbiological diagnostic testing was performed in all cases. C-reactive protein serum levels and white blood cell counts were evaluated, and the periprosthetic tissue was stained immunohistologically for the terminal complement pathway components (C3, C5, and C9) and for CD68 and α-defensin. RESULTS: Microbiological diagnostic testing detected a periprosthetic infection in 10 reverse shoulder arthroplasties and in 4 anatomic shoulder arthroplasties, while the remaining 19 shoulder arthroplasties were classified as aseptic. We observed more Staphylococcus epidermidis infections in reverse shoulder arthroplasties and more Staphylococcus aureus infections in anatomic shoulder arthroplasties. The revision rate correlated with pre-existing comorbidities and number of previous surgical procedures. The C-reactive protein values and the incidence of specific periprosthetic radiolucent lines were significantly increased in septic revision cases. We found increased staining for all tested complement factors (C3, C5, and C9) but not for α-defensin and CD68 in septic tissue. The most interesting finding was that C9 separated septic from aseptic tissue with a predictive specificity of 100% and a sensitivity of 88.89%. CONCLUSION: We observed a strong correlation between C9 expressions in septic revision tissue. We propose that the terminal complement pathway, especially C9 deposition, may be a potential biomarker to identify septic complications using tissue biopsy specimens.

[Rhinocerebral Mucormycosis]. / Rhinocerebrale Mucormykose.

Mucormycosis is a rare but serious type of fungal infection, which can progress rapidly especially in immunsupressed patients.We report about a 47 year old female patient with ptosis on the left eye. The ophthalmological report offered no further pathologic findings. Diabetes mellitus was known and the blood sugar value was very high.A computed tomography of the paranasal sinuses showed a shadow in the ethmoid bone and in an additonally performed MRI-scan, an increase of orbital fat and an extension of the ocular muscle were visible.As the patient lost her ability o look above, an operation of the paranasal sinus was done.The microbial results revealed a Mucormycosis (Lichtheimia). As the patient went blind in the further course, indication for orbital exenteration on the left side and revision of the paranasal sinus was given. High doses of Liposomal Ampthotericin B and Posaconazol were given and blood sugar was monitored very strictly. MRI-scans revealed a further progression of the infection and required additional surgeries and a dura resection accompanied by complications like recurrent septical episodes, renal insufficiency, a bifrontal epidural hematoma and multiple cerebral microinfarcts that impeded the recovery of our patient in the further course. After 8 months she was able to leave the hospital, an epithesis was adjusted and she is without a relapse for 24 month since the diagnosis.

Congenital cytomegalovirus infection in Central Germany: an underestimated risk.

PURPOSE: This is the first study to determine the cytomegalovirus (CMV) seronegativity rate for women of childbearing age in Saxony-Anhalt and to determine the prevalence of clinically relevant congenital CMV (cCMV) infection in Central Germany, because there are no valid data available. METHODS: The retrospective study was undertaken between January 2005 and December 2015. For the first time in Germany, the following seven data sources were used to analyze the prevalence of clinically relevant cCMV infection and the rate of CMV seronegative women of childbearing age: CMV Screening in maternity unit, University Women's Hospital, Social Paediatrics Centre (SPC), Malformation Monitoring Centre (MMC), Newborn Hearing Screening (NHS), Neonatal Intensive Care Unit (NICU), and In-house Doctor Department. Key parameters were anti-CMV IgG and IgM, CMV PCR of urine, and clinically relevant symptoms caused by CMV. RESULTS: Between 46 and 52% of women of childbearing age were CMV seronegative. The prevalence of clinically relevant cCMV infection was between 0.008 and 0.04%. CONCLUSIONS: The CMV seronegativity rate of women of childbearing age was confirmed to be in the middle range of estimated data from other sources in Germany. Data from the NICU, SPC, NHS, and MMC show the prevalence of clinically relevant cCMV infection. The risk of all cCMV infections is underestimated. Thus, the true prevalence of clinically relevant and subclinical cCMV infections is >0.04%.

Management of a cluster of Clostridium difficile infections among patients with osteoarticular infections.

BACKGROUND: Here we describe a cluster of hospital-acquired Clostridium difficile infections (CDI) among 26 patients with osteoarticular infections. The aim of the study was to define the source of C. difficile and to evaluate the impact of general infection control measures and antibiotic stewardship on the incidence of CDI. METHODS: Epidemiological analysis included typing of C. difficile strains and analysis of possible patient to patient transmission. Infection control measures comprised strict isolation of CDI patients, additional hand washings, and intensified environmental cleaning with sporicidal disinfection. In addition an antibiotic stewardship program was implemented in order to prevent the use of CDI high risk antimicrobials such as fluoroquinolones, clindamycin, and cephalosporins. RESULTS: The majority of CDI (n = 15) were caused by C. difficile ribotype 027 (RT027). Most RT027 isolates (n = 9) showed high minimal inhibitory concentrations (MIC) for levofloxacin, clindamycin, and remarkably to rifampicin, which were all used for the treatment of osteoarticular infections. Epidemiological analysis, however, revealed no closer genetic relationship among the majority of RT027 isolates. The incidence of CDI was reduced only when a significant reduction in the use of fluoroquinolones (p = 0.006), third generation cephalosporins (p = 0.015), and clindamycin (p = 0.001) was achieved after implementation of an intensified antibiotic stewardship program which included a systematic review of all antibiotic prescriptions. CONCLUSION: The successful reduction of the CDI incidence demonstrates the importance of antibiotic stewardship programs focused on patients treated for osteoarticular infections.

Prediction of central venous catheter-related bloodstream infections (CRBSIs) in patients with haematologic malignancies using a modified Infection Probability Score (mIPS).

The aim of this study was to predict the probability of central venous catheter-related bloodstream infections (CRBSIs) in patients with haematologic malignancies using a modified version of the Infection Probability Score (mIPS). In order to perform a prospective, mono-centric surveillance of complications in clinical routine due to short-term central venous catheters (CVCs) in consecutive patients receiving chemotherapy from March 2013 to September 2014, IPS was calculated at CVC insertion and removal (mIPSin and mIPSex, respectively). We used the 2012 Infectious Diseases Working Party of the German Society of Haematology and Medical Oncology (AGIHO/DGHO) criteria to define CRBSI. In total, 143 patients (mean 59.5 years, 61.4 % male) with 267 triple-lumen CVCs (4044 CVC days; mean 15.1 days, range 1-60 days) were analysed. CVCs were inserted for therapy of acute leukaemia (53.2 %), multiple myeloma (24.3 %) or lymphoma (11.2 %), and 93.6 % were inserted in the jugular vein. A total of 66 CRBSI cases (24.7 %) were documented (12 definite/13 probable/41 possible). The incidence was 16.3/1000 CVC days (2.9/3.1/10.1 per 1000 CVC days for definite/probable/possible CRBSI, respectively). In CRBSI cases, the mIPSex was higher as compared to cases without CRBSI (13.1 vs. 7.1; p < 0.001). The best mIPSex cutoff for CRBSI prediction was 8 points (area under the curve (AUC) = 0.77; sensitivity = 84.9 %, specificity = 60.7 %, negative predictive value = 92.4 %). For patients with an mIPSex ≥8, the risk for a CRBSI was high (odds ratio [OR] = 5.9; p < 0.001) and even increased if, additionally, CVC had been in use for about 10 days (OR = 9.8; p < 0.001). In case other causes of infection are excluded, a mIPSex ≥8 and duration of CVC use of about 10 days predict a very high risk of CRBSI. Patients with a mIPSex <8 have a low risk of CRBSI of 8 %.

Brain temperature measured by 1H-NMR in conjunction with a lanthanide complex.

In vivo data on temperature distributions in the intact brain are scarce, partly due to lack of noninvasive methods for the region of interest. NMR has been exploited for probing a variety of brain activities in vivo noninvasively within the region of interest. Here we report the use of a thulium-based thermometric sensor, infused through the blood, for monitoring absolute temperature in rat brain in vivo by (1)H-NMR and validated by direct temperature measurements with thermocouple wires. Because the (1)H chemical shifts also demonstrate pH sensitivity, detection of multiple resonances was used to measure both temperature and pH simultaneously with high sensitivity. Examination of blood plasma and cerebral spinal fluid samples removed from rats infused with the thermometric sensor suggests that the complex, despite its negative charge, crosses the blood-brain barrier to enter the extracellular milieu. In the future, the thulium-based thermometric sensor may be used for monitoring temperature (and pH) distributions throughout the entire brain, examining response to therapy and evaluating changes induced by alterations in neuronal activity.