Tuberculosis in Ukrainian War Refugees and Migrants in the Czech Republic and Slovakia: A Molecular Epidemiological Study

BACKGROUND

The war in Ukraine has led to significant migration to neighboring countries, raising public health concerns. Notable tuberculosis (TB) incidence rates in Ukraine emphasize the immediate requirement to prioritize approaches that interrupt the spread and prevent new infections.

METHODS

We conducted a prospective genomic surveillance study to assess migration's impact on TB epidemiology in the Czech Republic and Slovakia. Mycobacterium tuberculosis isolates from Ukrainian war refugees and migrants, collected from September 2021 to December 2022 were analyzed alongside 1574 isolates obtained from Ukraine, the Czech Republic, and Slovakia.

RESULTS

Our study revealed alarming results, with historically the highest number of Ukrainian tuberculosis patients detected in the host countries. The increasing number of cases of multidrug-resistant TB, significantly linked with Beijing lineage 2.2.1 (p < 0.0001), also presents substantial obstacles to control endeavors. The genomic analysis identified the three highly related genomic clusters, indicating the recent TB transmission among migrant populations. The largest clusters comprised war refugees diagnosed in the Czech Republic, TB patients from various regions of Ukraine, and incarcerated individuals diagnosed with pulmonary TB specialized facility in the Kharkiv region, Ukraine, pointing to a national transmission sequence that has persisted for over 14 years.

CONCLUSIONS

The data showed that most infections were likely the result of reactivation of latent disease or exposure to TB before migration rather than recent transmission occurring within the host country. However, close monitoring, appropriate treatment, careful surveillance, and social support are crucial in mitigating future risks, though there is currently no evidence of local transmission in EU countries.

Resistance patterns and transmission of mono- and polyresistant TB: clinical impact of WGS

Objectives

Rapidly diagnosing drug-resistant TB is crucial for improving treatment and transmission control. WGS is becoming increasingly accessible and has added value to the diagnosis and treatment of TB. The aim of the study was to perform WGS to determine the rate of false-positive results of phenotypic drug susceptibility testing (pDST) and characterize the molecular mechanisms of resistance and transmission of mono- and polyresistant Mycobacterium (M.) tuberculosis.

Methods

WGS was performed on 53 monoresistant and 25 polyresistant M. tuberculosis isolates characterized by pDST. Sequencing data were bioinformatically processed to infer mutations encoding resistance and determine the origin of resistance and phylogenetic relationship between isolates studied.

Results

The data showed the variable sensitivity and specificity of WGS in comparison with pDST as the gold standard: isoniazid 92.7% and 92.3%; streptomycin 41.9% and 100.0%; pyrazinamide 15% and 94.8%; and ethambutol 75.0% and 98.6%, respectively. We found novel mutations encoding resistance to streptomycin (in gidB) and pyrazinamide (in kefB). Most isolates belonged to lineage 4 (80.1%) and the overall clustering rate was 11.5%. We observed lineage-specific gene variations encoding resistance to streptomycin and pyrazinamide.

Conclusions

This study highlights the clinical potential of WGS in ruling out false-positive drug resistance following phenotypic or genetic drug testing, and recommend this technology together with the WHO catalogue in designing an optimal individualized treatment regimen and preventing the development of MDR TB. Our results suggest that resistance is primarily developed through spontaneous mutations or selective pressure.

Whole genome sequencing of multidrug-resistant Mycobacterium tuberculosis isolates collected in the Czech Republic, 2005-2020

The emergence and spread of resistant tuberculosis (TB) pose a threat to public health, so it is necessary to diagnose the drug-resistant forms in a clinically short time frame and closely monitor their transmission. In this study, we carried out a first whole genome sequencing (WGS)-based analysis of multidrug resistant (MDR) M. tuberculosis strains to explore the phylogenetic lineages diversity, drug resistance mechanisms, and ongoing transmission chains within the country. In total, 65 isolates phenotypically resistant to at least rifampicin and isoniazid collected in the Czech Republic in 2005-2020 were enrolled for further analysis. The agreement of the results obtained by WGS with phenotypic drug susceptibility testing (pDST) in the determination of resistance to isoniazid, rifampicin, pyrazinamide, streptomycin, second-line injectables and fluoroquinolones was more than 80%. Phylogenetic analysis of WGS data revealed that the majority of MDR M. tuberculosis isolates were the Beijing lineage 2.2.1 (n = 46/65; 70.8%), while the remaining strains belonged to Euro-American lineage. Cluster analysis with a predefined cut-off distance of less than 12 single nucleotide polymorphisms between isolates showed 19 isolates in 6 clusters (clustering rate 29.2%), located mainly in the region of the capital city of Prague. This study highlights the utility of WGS as a high-resolution approach in the diagnosis, characterization of resistance patterns, and molecular-epidemiological analysis of resistant TB in the country.

Anti-tuberculosis drug resistance in Slovakia, 2018-2019: The first whole-genome epidemiological study

•

The Euro-American lineage 4.7 was the most represented among the XDR-TB/MDR-TB resistant strains.

•

Seven of 12 isolates (58%) belonged to the same recent transmission chain.

•

Strains originally from Eastern European countries were diagnosed in patients without any epidemiological links with these countries.

•

Incidence of resistant XDR-TB/MDR-TB in Slovakia, while low, still should be taken to monitor.

Objective

The resistance of Mycobacterium (M.) tuberculosis to antituberculosis drugs poses a major threat to global public health. Whole genome sequencing (WGS) is an increasingly preferred method in the diagnostics and monitoring of the transmission dynamics of resistant forms of tuberculosis (TB). The aim of the study was to, for the first time, use the sequencing-based analysis to study the transmission and resistance patterns of a systematic and recent collection of extensively drug resistant (XDR) and multidrug resistant tuberculosis (MDR-TB) isolates and to expand our knowledge about drug resistant (DR) TB epidemiological dynamics in Slovakia.

Design

A total of 495 patients with pulmonary TB, who were referred to National Reference Laboratory for Mycobacteriology (Vyšné Hágy, Slovakia) in the years 2018–2019, were studied. Out of the total of 495 patients, 4 XDR-TB (0.8%) and 8 (1.6%) MDR-TB isolates were identified by conventional drug susceptibility testing on Löwenstein-Jensen solid medium and subjected to whole genome sequencing. Sequencing data were evaluated for molecular-epidemiological analysis and identification of resistance patterns.

Results

Phylogenetic and cluster analysis showed extensive recent transmission events and the predominance of Euro-American lineage 4.7 in Slovakia. However, phylogenetic analysis revealed the circulation of several lineages that originally occurred in Eastern European countries. Resistance patterns for first- and second-line antituberculosis drugs characterized by whole genome sequencing were in high concordance with the results of phenotypic drug susceptibility testing.

Conclusion

Forty percent of at least MDR-TB isolates were not genetically linked, indicating that appropriate measures should be taken to monitor and prevent the spread of drug-resistant tuberculosis within the country as well as in other regions.

Detection of Mycobacterium tuberculosis complex in pulmonary and extrapulmonary samples with the FluoroType MTBDR assay

OBJECTIVES

Rifampicin (RIF) and isoniazid (INH) are the two most effective first-line antibiotic drugs for the treatment of tuberculosis (TB). The new FluoroType MTBDR (FT-MTBDR) real-time PCR is intended to detect INH and RIF resistance mutations as a second step following a primary Mycobacterium tuberculosis complex (MTBC) PCR. Here we evaluate the feasibility of the FT-MTBDR assay to detect simultaneously MTBC-specific DNA as well as to detect potential INH and RIF resistance through analysing inhA promotor, katG and rpoB sequences in one PCR reaction.

METHODS

We analysed 3885 consecutive primary samples with FT-MTBDR and compared the results with microscopy and culture: 978 were from sputum, 2007 from other respiratory tract locations plus gastric lavages, and 875 from extrapulmonary locations, respectively.

RESULTS

Overall, 176 samples were MTBC culture positive and 139 FT-MTBDR positive, providing a FT-MTBDR sensitivity of 0.714 (95% confidence interval 0.640-0.779) and specificity of 0.996 (0.994-0.998), respectively. For the 978 sputum, 96 were MTBC culture positive and 89 FT-MTBDR positive, sensitivity 0.854 (0.764-0.915) and specificity 0.992 (0.983-0.997). Of the 139 MTBC positive, 99 (71%) had interpretable genotypic resistance results for at least one drug, 92 (66%) for both drugs.

DISCUSSION

The ability of FT-MTBDR to detect MTBC is adequate with the significant added feature of simultaneous genotypic resistance detection of both INH and RIF in a single PCR reaction.

Whole-genome sequencing and Mycobacterium tuberculosis: Challenges in sample preparation and sequencing data analysis

The numbers of patients with tuberculosis (TB) caused by resistant strains are still alarming. Therefore, it is necessary to determine resistance more quickly and precisely, than it is with the currently used phenotypic and genotypic methods. In recent years, technological advances have been made and the whole-genome sequencing (WGS) method has been introduced as a part of routine diagnostics in clinical laboratories. Comparing a wide range of mycobacterial genomic variations with a reference genome leads to a consistent evaluation of molecular-epidemiology and resistance of Mycobacterium tuberculosis (M. tuberculosis) to a wide range of anti-TB drugs. The quality of the obtained sequencing data is closely related to the type of sample and the method used for DNA extraction and sequencing library preparation. Moreover, the correct interpretation of results is also influenced by a bioinformatic data processing. A large number of bioinformatics pipelines are currently available, the sensitivity of which varies due to the different sizes of databases containing relevant mutations. This review focuses on the individual steps included in the sequencing workflow and factors that may affect the interpretation of final results.

Recurrent tuberculosis in patients infected with the predominant Mycobacterium tuberculosis outbreak strain in Denmark. New insights gained through whole genome sequencing

OBJECTIVES

Recurrent tuberculosis (TB) is defined by more than one TB episode per patient and is caused by reinfection with a new M. tuberculosis (Mtb) strain or relapse with the previous strain. In Denmark, a major TB outbreak caused by one specific Mtb genotype "DKC2" is ongoing. Of the 892 patients infected with DKC2 between 1992 and 2014, 32 had recurrent TB with 67 TB episodes in total.

METHODS

The 32 cases were evaluated in terms of number of single-nucleotide polymorphism (SNP) differences and time between episodes derived from whole-genome sequencing data.

RESULTS

For four TB cases, the subsequent episodes could be confirmed as relapse and for one case as reinfection. Eight cases with SNP differences <6, theoretically indicating relapse, could be classified as likely reinfections based on phylogenetic analysis in combination with geographical data. Subsequent TB episodes for the remaining 19 cases could not be classified as relapse or reinfection even though they all had a SNP difference of <6 SNPs.

CONCLUSIONS

In newer studies, investigating recurrent TB with the use of WGS, the number of SNPs has been used to distinguish between relapse and reinfection. The algorithm proposed for this is not valid in the Danish TB outbreak setting as our findings challenge the interpretation of few SNP differences as representing relapse. However, when including phylogenetic analysis and geographical data in the analysis, classification of 13 of the 32 cases were possible.

Mycobacterium arosiense, an unexpected cause of osteomyelitis in a patient with sarcoidosis: a case report

BACKGROUND

Nontuberculous mycobacteria belonging to the Mycobacterium avium complex are recognized as opportunistic pathogens to humans. Mycobacterium arosiense is one of the novel members of the Mycobacterium avium complex. The organism has only rarely been reported in human clinical cases and may be routinely misidentified.

CASE PRESENTATION

An adult male with a history of a discus prolapse and sarcoidosis presented with high fever and a strong back pain with projection to the extremities. A Magnetic Resonance Imaging scan of columna revealed a tumor suspect process at thoracic vertebrae 11/12 with changes at the second lumbar vertebra, which was partly removed by laminectomy. Biopsy smears revealed acid-fast bacilli and turned out to be Mycobacterium tuberculosis complex PCR negative. The routine line probe assay INNO-LiPa v2 (INNOGENETICS NV, Gent), which differentiates 16 mycobacterial species indicated the presence of a not readily identifiable NTM species. Whereas, the GenoType Mycobacterium CM v2.0 (HAIN Lifescience GmbH) that routinely differentiates 14 clinically relevant mycobacteria revealed a Mycobacterium intracellulare species. However, additional diagnostic sequencing of the 16S rRNA gene confirmed the presence of a Mycobacterium arosiense species.

CONCLUSIONS

This is the second unusual case of osteomyelitis with clinical significance ever to be reported, caused by Mycobacterium arosiense and complicated by an underlying sarcoidosis. Mycobacterium arosiense has rarely been reported clinically and the first description of the species was identified as the cause of osteomyelitis in a child with a hereditary partial interferon gamma deficiency. Symptoms attributed to sarcoidosis waned on Mycobacterium arosiense treatment and it is inconclusive whether the patient ever suffered from sarcoidosis. Mycobacterium arosiense was misidentified by the GenoType as Mycobacterium intracellulare and implicates that the diagnosis requires supplemental sequencing of the 16S rRNA gene.

Set-up and validation of mycobacterial interspersed repetitive unit-variable number of tandem repeat (MIRU-VNTR) analysis of Mycobacterium tuberculosis using BioNumerics software

The objective was to describe and validate a new and alternative software procedure for 24-locus mycobacterial interspersed repetitive unit-variable number-tandem repeat (MIRU-VNTR) typing of Mycobacterium tuberculosis (Mtb) based on the multipurpose BioNumerics software. DNA from randomly selected isolates of Mtb from two European laboratories, including external control samples for MIRU-VNTR typing, were analysed. Samples were genotyped using the commercial 24-locus VNTR typing kit from GenoScreen. The PCR amplified fragments were separated by capillary electrophoresis. For the subsequent analyses, the currently used software GeneMapper was compared with BioNumerics. The endpoint was the level of concordance when comparing genotyping results obtained from BioNumerics with results obtained from GeneMapper and the ECDC proficiency study reference results. Also, the number of necessary manual standard size corrections and allele assignments in the two different software methods were compared. In total, 272 DNA samples, including the ECDC proficiency panel, were analysed. For all samples, there were 100% concordance of results. For a randomly selected set of 96 samples the numbers of manual corrections needed for size standards were 199 with GeneMapper versus zero for BioNumerics. The numbers of manual corrections for allele assignments were 122 with GeneMapper versus 16 with BioNumerics. In conclusion, we have validated the multipurpose software BioNumerics for standard 24-locus MIRU-VNTR typing and the software shows promising benefits in terms of simplification and minimization of hand-on time.

A Major Mycobacterium tuberculosis outbreak caused by one specific genotype in a low-incidence country: Exploring gene profile virulence explanations

Denmark, a tuberculosis low burden country, still experiences significant active Mycobacterium tuberculosis (Mtb) transmission, especially with one specific genotype named Cluster 2/1112-15 (C2), the most prevalent lineage in Scandinavia. In addition to environmental factors, antibiotic resistance, and human genetics, there is increasing evidence that Mtb strain variation plays a role for the outcome of infection and disease. In this study, we explore the reasons for the success of the C2 genotype by analysing strain specific polymorphisms identified through whole genome sequencing of all C2 isolates identified in Denmark between 1992 and 2014 (n = 952), and the demographic distribution of C2. Of 234 non-synonymous (NS) monomorphic SNPs found in C2 in comparison with Mtb reference strain H37Rv, 23 were in genes previously reported to be involved in Mtb virulence. Of these 23 SNPs, three were specific for C2 including a NS mutation in a gene associated with hyper-virulence. We show that the genotype is readily transmitted to different ethnicities and is also found outside Denmark. Our data suggest that strain specific virulence factor variations are important for the success of the C2 genotype. These factors, likely in combination with poor TB control, seem to be the main drivers of C2 success.

Genomic Epidemiology of a Major Mycobacterium tuberculosis Outbreak: Retrospective Cohort Study in a Low-Incidence Setting Using Sparse Time-Series Sampling

Since 1992, Denmark has documented the largest outbreak of tuberculosis in Scandinavia ascribed to a single genotype, termed C2/1112-15. As of spring 2017, the International Reference Laboratory of Mycobacteriology in Copenhagen has collected and identified isolates from more than a thousand cases belonging to this outbreak via routine mycobacterial interspersed repetitive units-variable number of tandem repeats typing. Here, we present a retrospective analysis of the C2/1112-15 dataset, based on whole-genome data from a sparse time series consisting of 5 randomly selected isolates from 23 years of sampling. Even if these data are derived from only 12% of the collected isolates, we have been able to extract important key information, such as mutation rate and conserved single-nucleotide polymorphisms to identify discrete transmission chains, as well as the possible historical origins of the outbreak.

An attenuated Mycobacterium tuberculosis clinical strain with a defect in ESX-1 secretion induces minimal host immune responses and pathology

Although Mycobacterium tuberculosis (M.tb) DK9897 is an attenuated strain, it was isolated from a patient with extrapulmonary tuberculosis and vaccination with a subunit vaccine (H56) induced poor protection against it. Both attenuation and lack of protection are because M.tb DK9897 cannot secrete the EsxA virulence factor nor induce a host response against it. Genome sequencing identified a frameshift mutation in the eccCa1 gene. Since the encoded EccCa1 protein provides energy for ESX-1 secretion, it suggested a defect in the ESX-1 type VII secretion system. Genetic complementation with a plasmid carrying the M.tb H37Rv sequence of eccCa1-eccCb1-pe35 re-established EsxA secretion, host specific EsxA T-cell responses, and increased strain virulence. The ESX-1 secretion defect prevents several virulence factors from being functional during infection and therefore attenuates M.tb. It precludes specific T-cell responses against strong antigens and we found very little in vivo cytokine production, gross pathology or granuloma formation in lungs from M.tb DK9897 infected animals. This coincides with M.tb DK9897 being unable to disrupt the phagosome membrane and make contact to the cytosol.

Mycobacterium chimaera in Heater-Cooler Units in Denmark Related to Isolates from the United States and United Kingdom

Mycobacterium chimaera was present at high rates (>80%) in heater–cooler units (HCUs) from all 5 thoracic surgery departments in Denmark. Isolates were clonal to HCU-associated isolates from the United States (including some from patients) and United Kingdom. However, M. chimaera from 2 brands of HCU were genetically distinct.

Performance of the GenoType MTBDRplus assay (v2.0) and a new extended GenoType MTBDRsl assay (v2.0) for the molecular detection of multi- and extensively drug-resistant Mycobacterium tuberculosis on isolates primarily from Lithuania

The emergence of extensively drug-resistant tuberculosis (XDR-TB) hampers infection control. To assess the performance of an extended rapid novel molecular analysis for the detection of resistance conferring mutations to fluoroquinolones (gyrA, gyrB genes) and aminoglycosides/cyclic peptides (16S rRNA rrs gene, eis promotor region) compared to phenotypic susceptibility and sequencing, 43 multidrug-resistant (MDR) and 10 susceptible clinical isolates were analyzed. Results were compared to a previous version. Molecular rifampin (rpoB gene) and isoniazid (katG gene, inhA promotor region) resistance was also analyzed. XDR-TB was confirmed in 13 (30%) MDR isolates. Molecular resistance was detected in 91% ofloxacin-, 83% aminoglycoside/cyclic peptide- and 100% kanamycin-resistant isolates. In conclusion, the novel assay is a useful supplement to phenotypic susceptibility testing in determining the presence of XDR-TB. Molecular kanamycin resistance detection was immensely improved compared to the previous version. Aminoglycoside/cyclic peptide susceptible isolates revealed eis promotor region resistance in 29%, reflecting low-level kanamycin susceptibility challenges.

Substantial molecular evolution and mutation rates in prolonged latent Mycobacterium tuberculosis infection in humans

The genome of Mycobacterium tuberculosis (Mtb) of latently infected individuals may hold the key to understanding the processes that lead to reactivation and progression to clinical disease. We report here analysis of pairs of Mtb isolates from putative prolonged latent TB cases. We identified two confirmed cases, and used whole genome sequencing to investigate the mutational processes that occur over decades in latent Mtb. We found an estimated mutation rate between 0.2 and 0.3 over 33 years, suggesting that latent Mtb accumulates mutations at rates similar to observations from cases of active disease.

Combined IL-12 receptor and IgA deficiency in an adult man intestinally infested by an unknown, non-cultivable mycobacterium

Interleukin-12 receptor deficiency is a well-described cause of human susceptibility to infection with low-virulent mycobacteria and Salmonella species. We identified a male patient presenting in his late forties with severe gastroenteropathy because of outbred infestation by a previously unknown mycobacterium. In addition to selective IgA deficiency, the patient was found to carry a not previously described R283X homozygous mutation in his IL12RΒ1 gene. Two of his sisters, a brother, and his four children were healthy, heterozygous carriers of the mutation. In this patient, the combination of two deficiencies could promote illness. Even though the IgA deficiency in itself does not predispose to mycobacterial disease, the lack of secreted IgA may have disturbed the intestinal homoeostasis and increased the susceptibility to the low-virulent mycobacterium that the patient was not able to clear because of his IL12R deficiency. Antimycobacterial chemotherapy and interferon-γ treatment for 2 years significantly improved his condition. This is the first description of IL12RΒ1 deficiency combined with another immunodeficiency, and we suggest that combinatory defects may circumvent the otherwise low penetrance of IL12RB1 deficiency.

The continuing search for Mycobacterium tuberculosis involvement in sarcoidosis: a study on archival biopsy specimens

INTRODUCTION

Increasing evidence indicates that mycobacteria may be involved in the aetiology and pathophysiology of sarcoidosis.

OBJECTIVES

To investigate the association between Mycobacterium tuberculosis complex infection and sarcoidosis.

METHODS

Mediastinal lymph node biopsy specimens (formalin-fixed, paraffin-embedded) from 52 Danish patients with sarcoidosis, 50 patients with mediastinal lymphadenopathy of other non-mycobacterial causes (negative controls) and 12 patients with histologically and/or culture-verified mycobacteriosis (positive controls) were included in the study. Biopsy samples were analysed for the presence of Mycobacterium tuberculosis complex by strand displacement assay and a subset of specimens were examined for bacterial rRNA by fluorescent in situ hybridisation using an eubacterial probe with general bacterial specificity (EUB338).

RESULTS

One patient with sarcoidosis displayed a positive M. tuberculosis complex test. All negative controls were negative in the test and 5/12 patients with mycobacteriosis were positive in the test. We detected M. tuberculosis complex DNA in 10-year-old biopsy samples. Thirty-six samples were tested with the eubacterial probe; of these, 67% were positive with no difference between patients and controls.

CONCLUSION

Our results do not support the hypothesis that M. tuberculosis complex infection is involved in the pathogenesis of sarcoidosis. However, we stress the importance of excluding mycobacteriosis in the diagnostic workup of sarcoidosis patients.

[Strengthening of laboratories is a new component in the global strategy for tuberculosis control]

Although old techniques remain important, new techniques offer new possibilities. Mutations conferring resistance to rifampin and isoniazid can be detected in primary specimens from infectious pulmonary cases. Infections can be detected with interferon-gamma release assays, and chains of transmission can be detected by mycobacteria interspersed repetitive units. Centralized diagnostics makes it possible to apply results of routine analyses in national and international surveillance.

Line probe assay for differentiation within Mycobacterium tuberculosis complex. Evaluation on clinical specimens and isolates including Mycobacterium pinnipedii

A line probe assay (GenoType MTBC) was evaluated for species differentiation within the Mycobacterium tuberculosis complex (MTBC). We included 387 MTBC isolates, 43 IS6110 low-copy MTBC isolates, 28 clinical specimens with varying microscopy grade, and 30 isolates of non-tuberculous mycobacteria. The assay was 100% specific and identified all 387 isolates and 98% of all IS6110 low-copy strains in concordance with the gold standard. The 2% discrepancy was caused by 1 isolate showing a faint restriction fragment length polymorphism (RFLP) pattern. The assay could provide specifies identification in 13 of 19 (68%) microscopy-positive specimens and 0 of 9 microscopy-negative specimens. To our surprise, the probe for M. africanum subtype I reacted with M. pinnipedii. This cross-reaction has not previously been reported. The assay was rapid, easy to perform and directly applicable in highly smear-positive specimens. We predict that the assay will enable enhanced surveillance of species-specific treatment outcome, which may change treatment regimens.

[Tuberculosis caused by Mycobacterium africanum]

Tuberculosis (TB) is caused by pathogenic species within the Mycobacterium tuberculosis complex (MTBC). In the present case, a 40-year-old African man was admitted acutely. Despite negative microscopy, anti-TB treatment was initialized. Thirteen hours after hospitalisation, the patient suffered circulatory failure and died. Post mortem material from the lungs and pericardia tested positive for MTBC and was identified as Mycobacterium africanum by a new molecular method that enables identification of six of the eight MTBC species and provides clinicians with species-specific results.

Sequencing strategy of mitochondrial HV1 and HV2 DNA with length heteroplasmy

We describe a method to obtain reliable mitochondrial DNA (mtDNA) sequences downstream of the homopolymeric stretches with length heteroplasmy in the sequencing direction. The method is based on the use of junction primers that bind to a part of the homopolymeric stretch and the first 2-4 bases downstream of the homopolymeric region. This junction primer method gave clear and unambiguous results using samples from 21 individuals with length heteroplasmy in the hypervariable regions HV1, HV2 or both. The method is of special value for forensic casework, because sequencing of both strands of an mtDNA region is preferable in order to reduce ambiguities in sequence determination.

Fluorescent SSCP of overlapping fragments (FSSCP-OF): a highly sensitive method for the screening of mitochondrial DNA variation

The mtDNA analysis (mtDNA) is increasingly being demanded for forensic purposes due to the fact that many times the use of standard nuclear marker fails to analyze degraded samples (such as bones) and specially for the analysis of hair shafts (a common sample in the crime scene). However, analysis of mtDNA sequencing implies a great lab effort when a high number of samples must be analyzed. The present work introduces a novel and reliable method for the screening of mtDNA variation in the first and second hypervariables (HV1 and HV2) regions which we have denominated fluorescent single strand conformation polymorphism (SSCP) of overlapping fragments (FSSCP-OF). FSSCP-OF is based on the basic theory of SSCP analysis and combines two complementary strategies: the use of PCR amplified overlapping fragments and fluorescent detection technology. The overlap region contains a high percentage (50%) of the d-loop mtDNA variation and for this reason, the probability to detect a polymorphic position by SSCP analysis is clearly increased in comparison to conventional SSCP methods due to the fact that the same polymorphic position is usually placed in a different "relative" position in the two overlapped fragments. The use of multicolor fluorescent technology allows also the multiplex amplification of overlapping fragment and its subsequent analysis in an automatic sequencer. We have analyzed 50 samples of unrelated individuals through the FSSCP-OF technique and we have found that using this methodology the probability to distinguish two samples with different sequences is close to 100%. FSSCP-OF has other important advantages with respect to previous screening methods, such as the automation and standardization of the protocols, which is of special interest for the forensic routine.

The sxa2-dependent inactivation of the P-factor mating pheromone in the fission yeast Schizosaccharomyces pombe

Haploid cells of the fission yeast Schizosaccharomyces pombe exist in one of two mating types, referred to as M and P. Conjugation occurs between cells of opposite mating type and is controlled by the reciprocal action of diffusible pheromones. Loss of function of the sxa2 gene in M cells causes hypersensitivity to the P-factor mating pheromone and a reduction in mating efficiency. Here we demonstrate the secretion of an sxa2-dependent carboxypeptidase that inactivates P-factor by removal of the C-terminal leucine residue.

Amino acid sequence of Coprinus macrorhizus peroxidase and cDNA sequence encoding Coprinus cinereus peroxidase. A new family of fungal peroxidases

Sequence analysis and cDNA cloning of Coprinus peroxidase (CIP) were undertaken to expand the understanding of the relationships of structure, function and molecular genetics of the secretory heme peroxidases from fungi and plants. Amino acid sequencing of Coprinus macrorhizus peroxidase, and cDNA sequencing of Coprinus cinereus peroxidase showed that the mature proteins are identical in amino acid sequence, 343 residues in size and preceded by a 20-residue signal peptide. Their likely identity to peroxidase from Arthromyces ramosus is discussed. CIP has an 8-residue, glycine-rich N-terminal extension blocked with a pyroglutamate residue which is absent in other fungal peroxidases. The presence of pyroglutamate, formed by cyclization of glutamine, and the finding of a minor fraction of a variant form lacking the N-terminal residue, indicate that signal peptidase cleavage is followed by further enzymic processing. CIP is 40-45% identical in amino-acid sequence to 11 lignin peroxidases from four fungal species, and 42-43% identical to the two known Mn-peroxidases. Like these white-rot fungal peroxidases, CIP has an additional segment of approximately 40 residues at the C-terminus which is absent in plant peroxidases. Although CIP is much more similar to horseradish peroxidase (HRP C) in substrate specificity, specific activity and pH optimum than to white-rot fungal peroxidases, the sequences of CIP and HRP C showed only 18% identity. Hence, CIP qualifies as the first member of a new family of fungal peroxidases. The nine invariant residues present in all plant, fungal and bacterial heme peroxidases are also found in CIP. The present data support the hypothesis that only one chromosomal CIP gene exists. In contrast, a large number of secretory plant and fungal peroxidases are expressed from several peroxidase gene clusters. Analyses of three batches of CIP protein and of 49 CIP clones revealed the existence of only two highly similar alleles indicating less peroxidase polymorphism in C. cinereus strains than observed in plants and white-rot fungi.

[In-hospital day for patients connected with the District Psychiatric Center in Svendborg. A controlled study]

As of 31.12.1990, the employment of bed-days and admissions was calculated for patients who had been connected with a district psychiatric centre for more than three years. A before-and-after comparison revealed a percentage reduction in the employment of bed-days as compared with a control group. This corresponds to the findings in other investigations. In the before-and-after analysis, various reductions are described according to the diagnostic groups. The reduction in bed-day employment consisted mainly of fewer readmissions and reduction in the group of long-term hospitalisations. A reduction also occurred in the group of patients who could characterized as least ill. In this group, a marked percentage reduction in bed-days was observed as compared with the control group and this was probably due to the good and continuous treatment after discharge offered by the district psychiatric centre. This investigation revealed that the employment of bed-days for a patient population receiving district psychiatric treatment after discharge can be reduced. Nevertheless, the most severely ill patients will still require periodic admission to hospital. The value of treatment after discharge of the "Svendborg Model" type does not provide scientifically valid arguments that hospital admission can be avoided where the most severely ill patients are concerned.