Dual-centre evaluation of the FluoroType MTBDR version 2 assay for detection of Mycobacterium tuberculosis complex and resistance-conferring mutations in pulmonary and extrapulmonary samples from Denmark, Germany and Sierra Leone

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.

Genomic diversity and clinical relevance of Mycobacterium simiae

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.

[Treatment of MDR, pre-XDR, XDR and rifampicin resistant tuberculosis or in case of intolerance to at least rifampicin in Austria, Germany and Switzerland - Amendment dated 19.09.2023 to the Sk2-Guideline: Tuberculosis in adulthood of the German Central Committee against Tuberculosis (DZK) on behalf of the German Respiratory Society (DGP)]

In December 2022, based on the assessment of new evidence, the World Health Organization (WHO) updated its guidelines for the treatment of drug-resistant tuberculosis (TB). The evaluation of both, these recommendations, and the latest study data, makes it necessary to update the existing guidelines on the treatment of at least rifampicin-resistant tuberculosis for the German-speaking region, hereby replacing the respective chapters. A shortened MDR-TB treatment of at least 6 month using the fixed and non-modifiable drug combination of bedaquiline, pretomanid, linezolid, and moxifloxacin (BPaLM) is now also recommended for Germany, Austria, and Switzerland under certain conditions. This recommendation applies to TB cases with proven rifampicin resistance, including rifampicin monoresistance. For treatment of pre-extensively drug resistant TB (pre-XDR-TB), an individualized treatment for 18 months adjusted to resistance data continues to be the primary recommendation. The non-modifiable drug combination of bedaquiline, pretomanid, and linezolid (BPaL) may be used alternatively in pre-XDR TB if all prerequisites are met. The necessary prerequisites for the use of BPaLM and BPaL are presented in this amendment to the S2k guideline for 'Tuberculosis in adulthood'.

[Tuberculosis Infection Control & Hygiene - Recommendations of the DZK]

Preventing the spread of the disease is an essential goal in the care and treatment of tuberculosis. In addition to early diagnosis and effective therapies, isolation of infectious patients and adequate hygiene measures are of particular importance for infection prevention. The present recommendations replace the previous recommendations "tuberculosis infection control" from 2012 and take into account the current national and international recommendations and as well as new scientific findings. After a description of the infection and the transmission pathways, the necessary prevention and hygiene measures in health care facilities are comprehensively presented. Since the last revision of the recommendations on infection prevention, international recommendations and the KRINKO recommendation on ending isolation have been changed. In accordance with this, under certain conditions in the case of sensitive tuberculosis, de-isolation in health care facilities can take place after 14 days without taking the sputum findings into account. The second part of the recommendations explains in detail the measures to be taken in special situations and areas, such as general practitioners, ambulance services and care facilities. Here, the recommendations on respiratory protection have been simplified; for staff, an FFP2 mask is now generally considered sufficient.

[Update: Diagnostics and treatment of pulmonary tuberculosis]

Molecular diagnostic tools have changed the approach to the detection of Mycobacterium tuberculosis and associated drug-resistance substantially. PCR-based technologies allow a more rapid detection with higher diagnostic sensitivity in pulmonary and extrapulmonary specimens. However, a real point of care test, which needs minimal technical resources remains missing. Genome sequencing technologies are currently changing tuberculosis drug resistance testing, and for some questions are replacing phenotypic drug resistance testing, based on culture.New evidence on treatment for drug-sensitive tuberculosis allows shortening of treatment to 4 months, or in selected cases even to 2 months based on the use of fluoroquinolones, high dose rifamycins and newly developed TB medicines.Such developments will very likely simplify the management of tuberculosis, although prevention remains the most important pillar of any tuberculosis related public health strategy.

[Treatment of tuberculosis: what is new?]

Never before have so many people around the world been simultaneously affected by tuberculosis. Tuberculosis is the leading cause of death from a bacterial infectious disease worldwide. The World Health Organization's ambitious goal from 2014 of achieving global elimination of tuberculosis does not seem realistic, but on current trends, tuberculosis could be eliminated in the European Union by 2040. Since the beginning of 2022, there have been more innovations for the treatment of tuberculosis than in no other comparable time period before. One month of rifapentine and isoniazid is effective in treating latent tuberculosis infection. However, rifapentine is licensed in the USA but not in the EU and must be imported for individual cases. The duration of the standard treatment for tuberculosis can be shortened to four months but this treatment regimen is also based on rifapentine, in addition to isoniazid, pyrazinamide, and moxifloxacin. The approval of rifapentine in Europe is a much-needed step towards shortening the treatment of tuberculosis. With new drugs an even shorter standard treatment of only 2 months is possible. The treatment of multidrug-resistant/rifampicin-resistant tuberculosis (MDR-/RR-TB) has been shortened to six months, the same length as the standard treatment available in Germany. The combination of bedaquiline, pretomanid, linezolid ± moxifloxacin, cured around 90% of affected patients were cured in studies with a treatment duration of six months. With 19 drugs in clinical trials, the treatment of tuberculosis is expected to continue to improve rapidly in the coming years.

Epidemiology and Prevalence of Oral Candidiasis in HIV Patients From Chad in the Post-HAART Era

Oral candidiasis remains a common problem in HIV-infected individuals, especially in sub-Saharan Africa. Here, we performed the first study in Chad on the prevalence of oral yeasts carriage and oral candidiasis in HIV-positive subjects from southern Chad and analyzed the influence of HAART, CD4⁺ T-cell numbers, and antimycotics in 589 patients. These patients were recruited from a specialized medical center for HIV patients in Sarh and from a rural medical health dispensary in the vicinity, including a total of 384 HIV-positive and 205 HIV-negative individuals. Yeasts obtained from oral specimen were identified by MALDI-TOF MS and their antifungal susceptibility profiles determined. The overall prevalence of yeast colonization and symptomatic oral candidiasis in HIV-infected patients was 25.1%. The prevalence of oral candidiasis was higher in untreated than in HAART-treated HIV-positive patients (16% vs. 2%; p < 0.01). Oral candidiasis was furthermore associated with high fungal burdens of Candida albicans and a CD4⁺ T-cell number <200/μl. A shift toward non-albicans Candida species was observed under nucleoside-based HAART therapy. Azole antifungal drug resistance was only observed for the intrinsically resistant species Candida krusei and Candida glabrata. Prevalence of oral candidiasis in the studied area was very low. The species distribution was similar to other countries around the world, with C. albicans being dominant. Candida dubliniensis was not isolated. Nucleoside-based HAART therapy significantly reduced oral colonization as well as occurrence of oral candidiasis caused by C. albicans and led to a species shift toward non-albicans species. Antifungal resistance was not yet a concern in Chad.

Tula Virus as Causative Agent of Hantavirus Disease in Immunocompetent Person, Germany

We report molecular evidence of Tula virus infection in an immunocompetent patient from Germany who had typical signs of hantavirus disease. Accumulating evidence indicates that Tula virus infection, although often considered nonpathogenic, represents a threat to human health.

Headspace analyses using multi-capillary column-ion mobility spectrometry allow rapid pathogen differentiation in hospital-acquired pneumonia relevant bacteria

Background

Hospital-acquired pneumonia (HAP) is a common problem in intensive care medicine and the patient outcome depends on the fast beginning of adequate antibiotic therapy. Until today pathogen identification is performed using conventional microbiological methods with turnaround times of at least 24 h for the first results. It was the aim of this study to investigate the potential of headspace analyses detecting bacterial species-specific patterns of volatile organic compounds (VOCs) for the rapid differentiation of HAP-relevant bacteria.

Methods

Eleven HAP-relevant bacteria (Acinetobacter baumanii, Acinetobacter pittii, Citrobacter freundii, Enterobacter cloacae, Escherichia coli, Klebsiella oxytoca, Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus mirabilis, Staphylococcus aureus, Serratia marcescens) were each grown for 6 hours in Lysogeny Broth and the headspace over the grown cultures was investigated using multi-capillary column-ion mobility spectrometry (MCC-IMS) to detect differences in the VOC composition between the bacteria in the panel. Peak areas with changing signal intensities were statistically analysed, including significance testing using one-way ANOVA or Kruskal-Wallis test (p < 0.05).

Results

30 VOC signals (23 in the positive ion mode and 7 in the negative ion mode of the MCC-IMS) showed statistically significant differences in at least one of the investigated bacteria. The VOC patterns of the bacteria within the HAP panel differed substantially and allowed species differentiation.

Conclusions

MCC-IMS headspace analyses allow differentiation of bacteria within HAP-relevant panel after 6 h of incubation in a complex fluid growth medium. The method has the potential to be developed towards a feasible point-of-care diagnostic tool for pathogen differentiation on HAP.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12866-021-02102-8.

Two Pandemics, One Challenge-Leveraging Molecular Test Capacity of Tuberculosis Laboratories for Rapid COVID-19 Case-Finding

In many settings, the ongoing coronavirus disease (COVID-19) pandemic coincides with other major public health threats, in particular tuberculosis. Using tuberculosis (TB) molecular diagnostic infrastructure, which has substantially expanded worldwide in recent years, for COVID-19 case-finding might be warranted. We analyze the potential of using TB diagnostic and research infrastructures for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) testing. We focused on quality control by adapting the 12 Quality System Essentials framework to the COVID-19 and TB context. We conclude that diagnostic infrastructures for TB can in principle be leveraged to scale-up SARS-CoV-2 testing, in particular in resource-poor settings. TB research infrastructures also can support sequencing of SARS-CoV-2 to study virus evolution and diversity globally. However, fundamental principles of quality management must be followed for both TB and SARS-CoV-2 testing to ensure valid results and to minimize biosafety hazards, and the continuity of TB diagnostic services must be guaranteed at all times.

The Rnf complex from the acetogenic bacterium Acetobacterium woodii: Purification and characterization of RnfC and RnfB

rnf genes are widespread in anaerobic bacteria and hypothesized to encode a respiratory enzyme that couples exergonic reduction of NAD with reduced ferredoxin as a reductant to vectorial ion (Na⁺, H⁺) translocation across the cytoplasmic membrane. However, despite its importance for the physiology of these bacteria, little is known about the subunit composition and the function of subunits. Here, we have purified the entire Rnf complex from the acetogen Acetobacterium woodii or after its production in Escherichia coli. These studies revealed covalently bound flavin in RnfB and RnfD. Unfortunately, the complex did not catalyze electron transfer from reduced ferredoxin to NAD. We, therefore, concentrated on the two cytosolic subunits RnfC and RnfB. RnfC was produced in E. coli, purified and shown to have 8.3 mol iron and 8.6 mol sulfur per mol of the subunit, consistent with the presence of two [4Fe-4S] centers, which were verified by EPR analysis. Flavins could not be detected, but RnfC catalyzed NADH-dependent FMN reduction. These data confirm RnfC as NADH-binding subunit and FMN as an intermediate in the electron transport chain. RnfB could only be produced as a fusion to the maltose-binding protein. It contained 25 mol iron and 26 mol sulfur, consistent with the predicted six [4Fe4S] centers. The FeS centers in RnfB were reduced with reduced ferredoxin as reductant. These data are consistent with RnfB as the ferredoxin-binding subunit of the complex.

Importation of Human Seoul Virus Infection to Germany from Indonesia

Seoul hantavirus–associated hemorrhagic fever with renal syndrome cases are rare outside Asia and have not yet been found in Germany. We report clinical and molecular evidence for a Seoul virus infection in a patient in Germany. The infection was most likely acquired during a stay in Sulawesi, Indonesia.

Fulminant Endophthalmitis in a Child Caused by Neisseria meningitidis Serogroup C Detected by Specific DNA

This case report describes a local Neisseria meningitidis eye infection with a long protracted course in a seemingly healthy previously vaccinated child. Bacterial infection was detected by polymerase chain reaction techniques.

Detection and validation of volatile metabolic patterns over different strains of two human pathogenic bacteria during their growth in a complex medium using multi-capillary column-ion mobility spectrometry (MCC-IMS)

Headspace analyses over microbial cultures using multi-capillary column-ion mobility spectrometry (MCC-IMS) could lead to a faster, safe and cost-effective method for the identification of pathogens. Recent studies have shown that MCC-IMS allows identification of bacteria and fungi, but no information is available from when on during their growth a differentiation between bacteria is possible. Therefore, we analysed the headspace over human pathogenic reference strains of Escherichia coli and Pseudomonas aeruginosa at four time points during their growth in a complex fluid medium. In order to validate our findings and to answer the question if the results of one bacterial strain can be transferred to other strains of the same species, we also analysed the headspace over cultures from isolates of random clinical origin. We detected 19 different volatile organic compounds (VOCs) that appeared or changed their signal intensity during bacterial growth. These included six VOCs exclusively changing over E. coli cultures and seven exclusively changing over P. aeruginosa cultures. Most changes occurred in the late logarithmic or static growth phases. We did not find differences in timing or trends in signal intensity between VOC patterns of different strains of one species. Our results show that differentiation of human pathogenic bacteria by headspace analyses using MCC-IMS technology is best possible during the late phases of bacterial growth. Our findings also show that VOC patterns of a bacterial strain can be transferred to other strains of the same species.

Spectrum of viral infections in patients with cystic fibrosis

This review explores the extensive influence of viral infections leading to chronic deterioration of lung function in patients with cystic fibrosis (CF). The mechanisms how viral agents affect the pathogenesis as well as the inflammatory and immune response of CF are discussed. Viral infections of the upper and lower respiratory tract due to viruses in CF patients and methods for diagnosis of respiratory viruses are described in detail. The importance of respiratory and non-respiratory viral agents for the pathogenesis, especially for the exacerbation of bacterial lower respiratory tract infections and course of CF, is stressed, especially emphasizing respiratory syncytial virus, influenza virus, rhinovirus, and human herpes viruses. Possible harmful effects of further viruses like adenovirus, bocavirus, coronavirus, metapneumovirus, parainfluenzavirus on the lung function of CF patients are discussed. The potential use of adenovirus-based vectors for somatic gene therapy is mentioned.

The influence of virus infections on the course of COPD

Chronic obstructive pulmonary disease (COPD) is extensively influenced by viral infections. The mechanisms of how viral agents affect the pathogenesis and prognosis of COPD are numerous. In general, patients with infectious exacerbations are characterized by longer hospitalization periods and greater impairment of several lung function parameters than those with non-infectious exacerbations. Prodromal, clinical, and outcome parameters fail to distinguish virally from non-virally induced illnesses in cases of exacerbations. The importance of infections with respiratory and non-respiratory viral agents for pathogenesis and course of COPD is detailed. Human adenovirus, non-respiratory viruses including human immunodeficiency virus, human metapneumovirus, influenza virus, human rhinovirus, and respiratory syncytial virus are especially stressed.

Rapid discrimination of Salmonella enterica serovar Typhi from other serovars by MALDI-TOF mass spectrometry

Systemic infections caused by Salmonella enterica are an ongoing public health problem especially in Sub-Saharan Africa. Essentially typhoid fever is associated with high mortality particularly because of the increasing prevalence of multidrug-resistant strains. Thus, a rapid blood-culture based bacterial species diagnosis including an immediate sub-differentiation of the various serovars is mandatory. At present, MALDI-TOF based intact cell mass spectrometry (ICMS) advances to a widely used routine identification tool for bacteria and fungi. In this study, we investigated the appropriateness of ICMS to identify pathogenic bacteria derived from Sub-Saharan Africa and tested the potential of this technology to discriminate S. enterica subsp. enterica serovar Typhi (S. Typhi) from other serovars. Among blood culture isolates obtained from a study population suffering from febrile illness in Ghana, no major misidentifications were observed for the species identification process, but serovars of Salmonella enterica could not be distinguished using the commercially available Biotyper database. However, a detailed analysis of the mass spectra revealed several serovar-specific biomarker ions, allowing the discrimination of S. Typhi from others. In conclusion, ICMS is able to identify isolates from a sub-Saharan context and may facilitate the rapid discrimination of the clinically and epidemiologically important serovar S. Typhi and other non-S. Typhi serovars in future implementations.

The respiratory molybdo-selenoprotein formate dehydrogenases of Escherichia coli have hydrogen: benzyl viologen oxidoreductase activity

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.

Improved clinical laboratory identification of human pathogenic yeasts by matrix-assisted laser desorption ionization time-of-flight mass spectrometry

The key to therapeutic success with yeast infections is an early onset of antifungal treatment with an appropriate drug regimen. To do this, yeast species identification is necessary, but conventional biochemical and morphological approaches are time-consuming. The recent arrival of biophysical methods, such as matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS), in routine diagnostic laboratories holds the promise of significantly speeding up this process. In this study, two commercially available MALDI-TOF MS species identification systems were evaluated for application in clinical diagnostics, using a geographically diverse collection of 1192 clinical yeast and yeast-like isolates. The results were compared with those of the classical differentiation scheme based on microscopic and biochemical characteristics. For 95.1% of the isolates, all three procedures consistently gave the correct species identification, but the rate of misclassification was greatly reduced in both MALDI-TOF MS systems. Furthermore, several closely related species (e.g. Candida orthopsilosis/metapsilosis/parapsilosis or Candida glabrata/bracarensis) could be resolved by both MALDI-TOF MS systems, but not by the biochemical approach. A significant advantage of MALDI-TOF MS over biochemistry in the recognition of isolates novel to the system was observed. Although both MALDI-TOF MS systems employed different approaches in the database structure and showed different susceptibilities to errors in database entries, these were negligible in terms of clinical usefulness. The time-saving benefit of MALDI-TOF MS over biochemical identification will substantially improve fungal diagnostics and patient treatment.

On the Nonlinear Creep and Recovery of Open Cell Earplug Foams

The compressive creep and recovery of foam earplugs was studied at various applied stresses leading to different final creep strains. Deformation was determined from digital videos of the earplugs via image processing software. Creep could not be modeled by a single exponential in time; creep approximated a power law in time. Nonlinear viscoelasticity was observed: creep compliance depends on stress level. Nevertheless, for strain as high as 24%, recovery follows creep. Recovery does not follow creep at 70% strain. Recovery proceeds to completion given enough time.

Expression and localization of type III secretion-related proteins of Chlamydia pneumoniae

The entire developmental cycle of the obligate intracellular bacteria Chlamydia pneumoniae takes place within the inclusion body. As many gram negative bacteria, Chlamydia possess 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.

Molecular basis for persistent hepatitis B virus infection in the liver after clearance of serum hepatitis B surface antigen

Hepatitis B virus (HBV) DNA has been detected by polymerase chain reaction (PCR) in the liver of patients with resolved chronic HBV infection and sustained clearance of hepatitis B surface antigen (HBsAg) from serum. However, it is unknown whether the virus is transcriptionally active at this time or if the covalently closed circular (CCC) replicative intermediate of HBV DNA can still be detected. Therefore, hepatic nucleic acid extracts from seven patients who had cleared serum HBsAg were assessed by (PCR) for either reverse-transcribed HBV RNA, or an intact direct repeat region of the HBV genome indicative of the CCC replicative intermediate of HBV DNA. HBV transcripts were detected in four of seven patients in the study group, whereas an intact direct repeat region of the HBV genome was detected in three. Evidence for viral transcription and replication was more frequently detected in patients who had recently cleared serum HBsAg, but HBV RNA was also detected in one patient 5 years after HBsAg clearance, and an intact direct repeat region of HBV DNA was detected in another subject at nearly 4 years after resolution of disease. Therefore, hepatic HBV transcription may be associated with replicative intermediates of persistent HBV DNA in patients who have cleared HBsAg from serum, suggesting that, on occasion, HBV may not be in a latent state but undergoing low-level replication.

Improved clinical outcomes with liver transplantation for hepatitis B-induced chronic liver failure using passive immunization

OBJECTIVE

The goals were to summarize the results of liver transplantation for chronic hepatitis B disease (HBV) at the University of Virginia, correlate pretransplant viral markers with posttransplant hepatitis B immunoglobulin (HBIg) requirements, and identify the relation between viral protein in the liver and clinical reinfection.

SUMMARY BACKGROUND DATA

Liver transplantation is an accepted treatment for end-stage liver disease from chronic HBV infection, although lifelong antiviral treatment (with HBIg or antiviral agents) is still necessary. Patients with evidence of active viral replication (detectable serum HBV-DNA or e antigen) at the time of transplant have a higher rate of allograft infection. Whether clinically stable patients receiving HBIg immunoprophylaxis have detectable viral products in their grafts remains unknown.

METHODS

Forty-four transplants performed for HBV disease at the University of Virginia since March 1990 were reviewed. Most patients underwent aggressive passive immunoprophylaxis with HBIg to maintain serum HBV surface antibody (HBsAb) levels > or =500 IU/l for the first 6 months after the transplant, and > or =150 IU/l thereafter. Patients had viral markers quantified, underwent pharmacokinetic analysis of HBsAb levels to adjust dosing, and were biopsied routinely every 3 to 6 months and when indicated.

RESULTS

Forty-four transplants were performed in 39 patients. Actual 1-year and 3-year graft survival was 95% and 81%, respectively, and 1-year and 3-year patient survival was 98% and 96%, respectively. After the adoption of indefinite HBIg prophylaxis, nine grafts became infected (all in recipients positive for HBV e antigen). Three occurred within 8 weeks of transplantation and were associated with a short HBsAb half-life and a wild-type virus. Six occurred >8 months after the transplant, and most of these were associated with viral mutation. Quantification of pretransplant markers was an overall poor predictor of HBIg requirements after the transplant. Immunohistochemistry demonstrated transient low-level expression of core protein in the liver in 23% of patients without serum or clinical evidence of recurrent hepatitis.

CONCLUSIONS

An excellent outcome is possible after liver transplantation for chronic HBV disease using HBIg dosed by pharmacokinetic parameters. Currently, quantification of pretransplant serum markers of the HBV antigen load does not predict the intensity of posttransplant treatment required for good clinical outcomes. Because HBV is not eradicated from the patient, some form of indefinite antiviral therapy continues to be warranted.

Detection of hepatitis C virus RNA in hemodialysis patients

The clinical significance of the high prevalence of antibodies to hepatitis C virus (HCV) in dialysis patients remains undefined. In order to assess the relationship between seropositivity and potential infectivity, 63 patients undergoing maintenance hemodialysis were evaluated between April and May 1990. The mean duration of maintenance hemodialysis was 45 mo (range, 13 to 144). Eighty-two percent (52 of 63) had received blood transfusions, and 16% (10 of 63) had a history of iv drug abuse. Serum samples were analyzed by HCV-cDNA polymerase chain reaction; antibodies to HCV structural (core) and nonstructural regions NS3 and NS4 were determined by enzyme immunoassay. Specimens repeatedly reactive for anti-HCV and HCV-RNA-positive samples were tested by HCV MATRIX dot immunoblot assay and HBV-DNA PCR. Twenty-five percent (16 of 63) were anti-HCV-positive. Of the 16 anti-HCV-positive patients, HCV-RNA was detected in 5 (31%) with the NS3 primers and in 12 (75%) with 5'-noncoding primers. Among the anti-HCV-negative patients, HCV-RNA was detected in 2 (4.3%) of 47 patients. Eleven of the 18 patients with HCV infection (anti-HCV and/or HCV-RNA-positive) had evidence of additional present or past viral infections (human immunodeficiency virus and/or hepatitis B virus). In summary, HCV-RNA is present in at least 75% of anti-HCV-positive patients, suggesting that they may be infectious. The detection of HCV-RNA in anti-HCV-negative patients may indicate early or chronic HCV infection not detected by current antibody assays or the inability of these patients to mount or sustain a significant antibody response.

Mixed cryoglobulinemia in chronic hepatitis C infection. A clinicopathologic analysis of 10 cases and review of recent literature

We present 10 cases of mixed cryoglobulinemia in patients infected with hepatitis C, including pertinent clinical, serologic, and pathological data. The findings attributable to MC appear to be similar in patients who are HCV-infected as in those with unknown HCV status. The prevalence of MC in HCV-infected patients appears to be lower in our region (13%) than in southern Europe (50-90%) although some of this difference is due to our requirement that patients included in our study have a cryocrit of at least 5%. In our patients, cryoglobulins were shown to be deposited in skin and kidney, but not in liver. The mechanisms by which HCV and MC are related remain uncertain. Although we and others have evidence for enrichment of HCV RNA in the cryoprecipitates of some patients, this was not always the case, and it is not yet clear that this finding is of fundamental pathogenic importance. Finally, it appears that some patients with HCV and MC may have a beneficial clinical response of vasculitic symptoms to therapy with alpha-interferon, as well as to glucocorticoids or other immunosuppressants. In our group, no predictors were apparent to distinguish responders from nonresponders before treatment. Similarly, the duration of response remains to be determined.

Serum and liver hepatitis B virus DNA in chronic hepatitis B after sustained loss of surface antigen

Polymerase chain reaction (PCR) was used to detect hepatitis B virus DNA in the sera and livers of nine patients with chronic hepatitis B after treatment-induced or spontaneous loss of serum hepatitis B surface antigen. Patients were evaluated at intervals ranging from 3 to 67 months after disappearance of hepatitis B surface antigen. PCR was performed using primer pairs from the surface and core gene regions, and surface gene products were quantitated. Liver tissue was also evaluated by in situ hybridization to assess viral transcription. Five of the nine patients had viral DNA detectable in serum by PCR. Quantitation of polymerase chain reaction products in serum and liver showed that the DNA levels tended to decline progressively after antiviral therapy. Six of seven surface antigen-negative patients tested had detectable viral DNA in the liver, and four of the six DNA-positive patients were negative for DNA in serum by PCR. None had surface gene messenger RNA. Thus, it is concluded that hepatitis B virus DNA may be detectable by PCR in liver tissue years after the disappearance of hepatitis B surface antigen, even in the absence of detectable hepatitis B virus DNA in serum.

Complement and antibody mediate enhancement of HIV infection by increasing virus binding and provirus formation

Previous studies have shown that infection of complement receptor (CR2)-bearing cells with HIV pretreated with antibody (Ab) plus complement (C) resulted in increased virus expression. The current study was designed to determine whether C-mediated 'enhancement' of HIV-1 production was the result of increased virus infection of cells as assessed by provirus formation and virus binding. Virus was incubated with anti-HIV Ab and/or C and added to CR2-positive MT-2 cells. Increased virus expression by MT-2 cells correlated with increased numbers of HIV-immunofluorescent-positive cells at 24 and 48 h and higher levels of provirus detected 8-28 h after infection. MT-2 cells also bound threefold more Ab-plus-C-treated virus than untreated virus. Serial dilutions of C showed that high levels of C with Ab did not enhance but rather suppressed virus expression. Studies were also performed which showed that terminal C components C5 and C8 were not necessary for the enhancing effect. The increased binding of C-coated HIV to CR-positive cells has important implications for the fate of virus in vivo.

A randomized, controlled trial of interferon alfa-2b alone and after prednisone withdrawal for the treatment of chronic hepatitis B. The Hepatitis Interventional Therapy Group

BACKGROUND AND METHODS

Chronic hepatitis B is a common and often progressive liver disorder for which there is no accepted therapy. To assess the efficacy of treatment with interferon, we randomly assigned patients with chronic hepatitis B to one of the following regimens: prednisone for 6 weeks followed by 5 million units of recombinant interferon alfa-2b daily for 16 weeks; placebo followed by 5 million units of interferon daily for 16 weeks; placebo followed by 1 million units of interferon daily for 16 weeks; or observation with no treatment.

RESULTS

Hepatitis B e antigen and hepatitis B viral DNA disappeared from serum significantly more often in the patients given prednisone plus interferon (16 of 44 patients, or 36 percent) or 5 million units of interferon alone (15 of 41; 37 percent) than in the untreated controls (3 of 43; 7 percent; P less than 0.001); the difference between those given 1 million units of interferon (7 of 41; 17 percent) and the controls was not significant. The strongest independent predictor of a response to treatment was the amount of hepatitis B viral DNA in serum at entry (P less than 0.0001). Of the 38 patients who responded to interferon, 33 (87 percent) had normal serum aminotransferase levels after therapy; 11 patients who responded (29 percent), but no controls, lost the hepatitis B surface antigen. Blinded histologic assessment revealed a significant improvement in periportal necrosis in the treated patients (P = 0.03).

CONCLUSIONS

In chronic hepatitis B, treatment with interferon alfa-2b (5 million units per day for 16 weeks) was effective in inducing a sustained loss of viral replication and achieving remission, assessed biochemically and histologically, in over a third of patients. Moreover, in about 10 percent of the patients treated with interferon, hepatitis B surface antigen disappeared from serum.

Hepatitis B-like infection in a Pacific white-sided dolphin (Lagenorhynchus obliquidens)

A Pacific white-sided dolphin (Lagenorhynchus obliquidens) developed clinical signs, serum biochemical values, and serologic viral markers consistent with chronic persistent hepatitis caused by a hepatitis B-like virus. The hepatitis had a sporadic cyclical pattern of lethargy, inappetance, and icterus, with leukocytosis and increased serum activities of alanine transaminase, aspartate transaminase, and gamma-glutamyltransferase. The serum from this dolphin contained hepatitis B virus core antibodies, hepatitis B surface antibodies, and hepatitis B viral DNA. Supportive treatment consisted of administration of antibiotics, cimetidine, menadiol sodium diphosphate, and vitamin/dextrose supplementation. A clinically normal killer whale (Orcinus orca) housed in the same pool had serum hepatitis B surface antibodies, suggesting immunologic responsiveness and that this disease was not species-specific.

Comparison of a quantitative standardized HBV-DNA assay and a classical spot hybridization test in chronic active hepatitis B patients undergoing antiviral therapy

A quantitative solution hybridization assay (Genostics Tm hepatitis B viral DNA, Abbott Laboratories) for hepatitis B viral DNA (HBV DNA) in serum was compared with the classic spot hybridization test in chronic hepatitis B carriers undergoing antiviral therapy. Twenty-eight patients with HBsAg- and HBeAg-positive chronic liver disease were studied and 128 sera were analysed during treatment. Ninety-nine (86%) sera were found to be positive with the two assays. Fourteen sera were negative in both assays. Fifteen samples were positive by Genostics and negative by spot test. Therefore, the sensitivity of the Genostics assay was equivalent to or slightly greater than that of the spot test. Changes in HBV-DNA levels measured by the two assays showed a high correlation during therapy, but changes in the viral replication level seemed to be better resolved by Genostics. The Genostics assay represents a standardized, easy-to-use, quantitative method for the detection of HBV DNA in serum. It will be useful for monitoring antiviral therapy and should now be evaluated on a large scale.

Absence of pre-S2 antibodies in natural hepatitis B virus infection

Antibodies to the host "self" component human serum albumin (HSA) and to its receptor are induced by the pre-S2 encoded aminoacid sequence (120-145) of the middle surface protein on the hepatitis B virus (HBV) particle and are produced as part of the immune response during acute HBV-infection. The antibodies disappeared rapidly during the convalescence phase and were not detectable in patients with naturally acquired immunity to HB. These data raise questions about the importance of anti-pre-S2 antibodies for long-term protection against HBV-infection. The coexistence of HBV-DNA with antibodies to native HSA (nHSA) in 13/16 patients with biopsy proven liver disease and of HBV-DNA with anti-pre-S2 in 10/13 patients argues against the attribution of virus eliminating properties to antibodies directed against pre-S2 determinants. In fact circulating anti-nHSA and anti-pre-S2 persisted in 16/17 and 13/17 patients, respectively, with major HBV-induced liver disease but not in symptomless HBsAg carriers. This finding suggests that continuous production of antibodies against the "self" component HSA and/or its receptor structures are associated with the pathogenesis of chronic HBV-induced liver disease. Pre-S2 coded peptide sequences should thus not be incorporated into HB vaccines.

Value of impedance plethysmography in suspected venous disease of the lower extremity

We tested the correlation between impedance plethysmography (IPG) and venography (VG) in evaluating patients with suspected venous thrombosis of the lower extremity. Three hundred and eight limbs in 205 such patients were evaluated by both IPG and VG. With the results of the venograms as standards, 169 limbs (55%) were classified as "normal" and 139 limbs (45%) as "abnormal." Acute deep venous thrombosis (DVT) was present in 65 limbs, 47 of which had DVT of the major veins, popliteal and above. The correlated IPG was positive in 43 limbs, with a sensitivity of 91%, a specificity of 89%, and P < 0.001.