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The entire developmental cycle of the obligate intracellular bacteriaChlamydia pneumoniaetakes place within the inclusion body. As many gram negative bacteria,Chlamydiapossess a type III-secretion system (TTSS), which allows them to target effector molecules into the host cell. The expression and localization of several proteins constituting the TTSS apparatus and of proteins supposed to be secreted by the TTSS have been investigated. For the TTSS-constituting proteins, we selected representatives such as YscN (ATPase), LcrE (putative “lid” of the TTSS) and LcrH1 (postulated to be a chaperone). Furthermore, we focused on the putative effector proteins IncA, IncB, IncC, Cpn0809 and Cpn1020. Expression of these proteins was detected by reverse transcriptase-PCR followed by immunoblot analysis using antisera that were generated against the corresponding recombinant proteins. Thereby, expression could be detected on the RNA and/or protein level. Intracellular localization of proteins under investigation was determined by immunofluorescence assays using the respective antisera. YscN was shown to be distributed equally throughout the inclusion body, whereas LcrE gave a more prominent staining of the inclusion membrane. IncA was detected mainly on the membrane of the inclusion body, whereas IncB and IncC were shown to be located within the inclusion. Immunofluorescence assays with antisera raised against Cpn0809 and Cpn1020 showed completely different labeling. Signals corresponding to Cpn0809 and Cpn1020 were distributed within the host cell rather than inside the inclusions. Taken together, the different localization patterns of the effector proteins indicate differences in function and interplay with the host cell. [ABSTRACT FROM AUTHOR]

Study Objective: To determine the efficacy of a short course of prednisone followed by recombinant interferon treatment in patients with chronic type B hepatitis.Design: Randomized, controlled trial with a 5-month treatment phase and a 9-month observation period after treatment.Setting: Two referral-based university-affiliated medical centers.Patients: Thirty-nine clinically stable patients with chronic type B hepatitis, all of whom were positive for hepatitis B antigen, hepatitis B virus-associated-DNA (HBV-DNA), and DNA polymerase for at least 6 months before entry. Patients included 20 heterosexuals and 19 male homosexuals.Interventions: Eighteen patients were treated with a 6-week tapered regimen of prednisone, followed by 90 days treatment with recombinant interferon alpha-2b; 21 patients were untreated controls. Paired liver biopsy specimens of 27 patients (pretreatment and 9 months after treatment) were blindly evaluated.Measurements and Main Results: Nine treated patients had a sustained loss of HBV-DNA. In addition, eight treated patients lost hepatitis B e antigen and four became negative for hepatitis B surface antigen (HBsAg). When compared with controls the differences were statistically significant for clearance of HBV-DNA and HBsAg (P = 0.035 and 0.037, respectively). Treated patients who had a sustained loss of HBV-DNA had higher initial alanine aminotransferase lower initial DNA and DNA polymerase levels, and were more frequently heterosexual. Patients who responded to treatment with the disappearance of hepatitis B e antigen and HBV-DNA had normal liver function tests and markedly improved liver histology during follow-up.Conclusions: The immunologic priming provided by a short course of prednisone used with alpha interferon may be an effective treatment for selected patients with chronic type B hepatitis. [ABSTRACT FROM AUTHOR]

Abstract Background Escherichia coli synthesizes three membrane-bound molybdenum- and selenocysteine-containing formate dehydrogenases, as well as up to four membrane-bound [NiFe]-hydrogenases. Two of the formate dehydrogenases (Fdh-N and Fdh-O) and two of the hydrogenases (Hyd-1 and Hyd-2) have their respective catalytic subunits located in the periplasm and these enzymes have been shown previously to oxidize formate and hydrogen, respectively, and thus function in energy metabolism. Mutants unable to synthesize the [NiFe]-hydrogenases retain a H2: benzyl viologen oxidoreductase activity. The aim of this study was to identify the enzyme or enzymes responsible for this activity. Results Here we report the identification of a new H2: benzyl viologen oxidoreductase enzyme activity in E. coli that is independent of the [NiFe]-hydrogenases. This enzyme activity was originally identified after non-denaturing polyacrylamide gel electrophoresis and visualization of hydrogen-oxidizing activity by specific staining. Analysis of a crude extract derived from a variety of E. coli mutants unable to synthesize any [NiFe]-hydrogenase-associated enzyme activity revealed that the mutants retained this specific hydrogen-oxidizing activity. Enrichment of this enzyme activity from solubilised membrane fractions of the hydrogenase-negative mutant FTD147 by ion-exchange, hydrophobic interaction and size-exclusion chromatographies followed by mass spectrometric analysis identified the enzymes Fdh-N and Fdh-O. Analysis of defined mutants devoid of selenocysteine biosynthetic capacity or carrying deletions in the genes encoding the catalytic subunits of Fdh-N and Fdh-O demonstrated that both enzymes catalyze hydrogen activation. Fdh-N and Fdh-O can also transfer the electrons derived from oxidation of hydrogen to other redox dyes. Conclusions The related respiratory molybdo-selenoproteins Fdh-N and Fdh-O of Escherichia coli have hydrogen-oxidizing activity. These findings demonstrate that the energy-conserving selenium- and molybdenum-dependent formate dehydrogenases Fdh-N and Fdh-O exhibit a degree of promiscuity with respect to the electron donor they use and identify a new class of dihydrogen-oxidizing enzyme.

Background: Mycobacterium chelonae is a rare cause of infective endocarditis that is difficult to diagnose and treat. After we found M chelonae in a series of patients, we aimed to investigate its role in cardiovascular prosthesis dysfunction and contamination of bioprostheses as a possible cause of infection., Methods: In this collaborative microbiological study, we report on nine patients treated in three cardiovascular surgical departments in Germany, who were found to have M chelonae infection after receiving BioIntegral bioprostheses. We performed fluorescence in-situ hybridisation (FISH) combined with broad-range 16S rRNA gene amplification and sequencing (FISHseq) on samples of native cardiovascular tissue and explanted bioprosthetic material, as well as on 12 unused BioIntegral prostheses. We confirmed FISHseq findings with histological examination by staining for acid-fast bacilli, and M chelonae was differentiated from M abscessus by molecular techniques., Findings: Between Dec 1, 2020, and Feb 28, 2022, we identified M chelonae in BioIntegral bioprostheses from three initial patients treated in Berlin that were explanted following dysfunction or suspected endocarditis, visualising morphologically intact FISH-positive mycobacteria. Despite negative mycobacterial culture, we also detected M chelonae in all 12 unused BioIntegral prostheses. The competent authorities in the EU prompted an alert, leading to the identification of six additional patients between March 1, 2022, and July 31, 2023. To find other cases of M chelonae endocarditis, we reviewed the FISHseq results of 1237 cardiovascular samples that were analysed between Jan 1, 2015, and Aug 31, 2022, including 295 samples from 228 bioprostheses supplied by other manufacturers. M chelonae was only detected in six of 41 patients who had received BioIntegral products., Interpretation: Bioprostheses manufactured by BioIntegral Surgical might be colonised by M chelonae, which can lead to implant dysfunction. These infections are likely to be missed by conventional routine diagnostics and should be considered in patients with BioIntegral implants and suspected infection or dysfunction. Cases should be reported to public health and regulatory authorities. Routine safety testing of bioprostheses during manufacture should be reconsidered., Funding: German Federal Ministry of Education and Research., Competing Interests: Declaration of interests JK and AM founded and run MoKi Analytics GmbH. AM founded and runs Moter Diagnostics. These two diagnostics laboratories investigated the samples with FISHseq originally and, after finding NTM, initiated and handed over this collaborative research to all other partners., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

We present a patient who suffered an agricultural rollover trauma and developed a fracture-associated tissue infection caused by Mycobacterium smegmatis. Since cases are rare, treatment of infections with M. smegmatis requires an interprofessional approach and the combination of surgery and adjunctive antimicrobial treatment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Inc.)

Objectives: We evaluated the ability of FluoroType MTBDR version 2 (FTv2; Hain Lifescience), a second-step real-time PCR assay, to simultaneously detect Mycobacterium tuberculosis complex (MTBC) DNA and mutations conferring resistance to rifampicin (RIF) and isoniazid (INH), in pulmonary and extrapulmonary samples from patients and compared them with corresponding cultures., Methods: FTv2 MTBC was evaluated on 1815 and 432 samples from Denmark (DK) and Germany (DE), respectively. RIF and INH resistance mutations were assessed in the German samples and 110 samples from Sierra Leone and subsequently compared to phenotypic antimicrobial susceptibility testing and a composite reference DNA (CRD) based on the GenoType MTBDR line-probe assay and Sanger sequencing or whole-genome sequencing., Results: Of the 584 (557 smear-negative) Danish and 277 (85 smear-negative) German sputum samples, 42 (16) and 246 (54) were culture positive, and 44 (18) and 222 (35) were FTv2 positive, providing an FTv2 sensitivity and specificity of 0.86 (0.63) and 0.98 (DK), 0.90 (0.65) and 1.00 (DE), respectively. The count, sensitivities, and specificities for all pulmonary samples were 1434, 0.79, and 0.99 (DK) and 347, 0.86, and 1.00 (DE), respectively; for extrapulmonary samples, 381, 0.33, 0.99 (DK) and 83, 0.50, and 1.00 (DE). The valid count, sensitivity, and specificity compared with CRD for detecting resistance mutations were RIF 355, 0.99, 0.96, and INH 340, 1.00, and 0.98, respectively., Discussion: FTv2 reliably detects MTBC DNA in pulmonary and extrapulmonary samples and detects resistance mutations for INH and RIF resistance in inhA promoter, katG, and rpoB genes., (Copyright © 2024 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

Background: The Mycobacterium avium complex (MAC) comprises the most frequent non-tuberculous mycobacteria (NTM) in Central Europe and currently includes twelve species. M. avium (MAV), M. intracellulare subsp. intracellulare (MINT), and M. intracellulare subsp. chimaera (MCH) are clinically most relevant. However, the population structure and genomic landscape of MAC linked with potential pathobiological differences remain little investigated., Methods: Whole genome sequencing (WGS) was performed on a multi-national set of MAC isolates from Germany, France, and Switzerland. Phylogenetic analysis was conducted, as well as plasmids, resistance, and virulence genes predicted from WGS data. Data was set into a global context with publicly available sequences. Finally, detailed clinical characteristics were associated with genomic data in a subset of the cohort., Results: Overall, 610 isolates from 465 patients were included. The majority could be assigned to MAV (n = 386), MCH (n = 111), and MINT (n = 77). We demonstrate clustering with less than 12 SNPs distance of isolates obtained from different patients in all major MAC species and the identification of trans-European or even trans-continental clusters when set into relation with 1307 public sequences. However, none of our MCH isolates clustered closely with the heater-cooler unit outbreak strain Zuerich-1. Known plasmids were detected in MAV (325/1076, 30.2%), MINT (62/327, 19.0%), and almost all MCH-isolates (457/463, 98.7%). Predicted resistance to aminoglycosides or macrolides was rare. Overall, there was no direct link between phylogenomic grouping and clinical manifestations, but MCH and MINT were rarely found in patients with extra-pulmonary disease (OR 0.12 95% CI 0.04-0.28, p < 0.001 and OR 0.11 95% CI 0.02-0.4, p = 0.004, respectively) and MCH was negatively associated with fulfillment of the ATS criteria when isolated from respiratory samples (OR 0.28 95% CI 0.09-0.7, p = 0.011). With 14 out of 43 patients with available serial isolates, co-infections or co-colonizations with different strains or even species of the MAC were frequent (32.6%)., Conclusions: This study demonstrates clustering and the presence of plasmids in a large proportion of MAC isolates in Europe and in a global context. Future studies need to urgently define potential ways of transmission of MAC isolates and the potential involvement of plasmids in virulence., (© 2024. The Author(s).)

Introduction: Mycobacterium simiae is a slow-growing non-tuberculous mycobacterium that can cause non-tuberculous mycobacterium (NTM) pulmonary disease and extrapulmonary infections. Until now, detailed genomic and clinical characteristics, as well as possible transmission routes of this rare pathogen remain largely unknown., Methods: We conducted whole genome sequencing of available M. simiae isolates collected at a tertiary care centre in Central Germany from 2006 to 2020 and set them into context with publicly available M. simiae complex sequences through phylogenetic analysis. Resistance, virulence and stress genes, as well as known Mycobacteriaceae plasmid sequences were detected in whole genome raw reads. Clinical data and course were retrieved and correlated with genomic data., Results: We included 33 M. simiae sensu stricto isolates from seven patients. M. simiae showed low clinical relevance with only two patients fulfilling American Thoracic Society (ATS) criteria in our cohort and three receiving NTM-effective therapy. The bacterial populations were highly stable over time periods of up to 14 years, and no instances of mixed or re-infections with other strains of M. simiae were observed. Clustering with <12 single nucleotide polymorphisms distance was evident among isolates from different patients; however, proof for human-to-human transmission could not be established from epidemiological data., Conclusion: Overall, the available sequence data for M. simiae complex was significantly extended and new insights into its pathogenomic traits were obtained. We demonstrate high longitudinal genomic stability within single patients. Although we cannot exclude human-to-human transmission, we consider it unlikely in the light of available epidemiological data., Competing Interests: Conflict of interest: N. Wetzstein, M. Diricks, S. Andres, M. Kuhns, L. Marschall, T. Biciusca, C. Smaczny, I. Friesen and S. Niemann have nothing to disclose. Conflict of interest: T.A. Wichelhaus reports research grants from BMBF, JPIAMR, Deutsche Krebshilfe and MSD, and speaker fees and consulting honoraria from Insmed and Osartis, all outside the submitted work., (Copyright ©The authors 2024.)