Molecular identification of human tuberculosis in recent and historic bone tissue samples: The role of molecular techniques for the study of historic tuberculosis

Developing an archaeology of malaria. A critical review of current approaches and a discussion on ways forward

OBJECTIVE

This paper presents the current state of the art in the investigation of past malaria by providing an extensive review of previous studies and identifying research possibilities for the future.

MATERIALS

All previous research on the detection of malaria in human skeletal material using macroscopic and biomolecular approaches is considered.

METHODS

The approaches and methods used by scholars and the results they obtained are evaluated and the limitations discussed.

RESULTS

There is a link between malaria and porous lesions with significantly higher prevalence in malaria-endemic areas, however, they are not pathognomonic or specific for malaria. Malaria can be identified using biomolecular techniques, yet, to date there is no completely satisfactory method that is able to consistently diagnose the disease.

CONCLUSIONS

Using macroscopic and biomolecular techniques, malaria can be investigated in past populations and the impact of the disease studied. Yet, this is not a straightforward process and the use of multiple lines of evidence is necessary to obtain the best results.

SIGNIFICANCE

The extensive discussion on ways malaria can and cannot be identified in past populations and the suggestions for new approaches provide a steppingstone for future research into this debilitating, global disease.

LIMITATIONS

Malaria is a difficult disease to study archaeologically and successful identification depends on many intrinsic and extrinsic factors.

SUGGESTIONS FOR FURTHER RESEARCH

More large-scale spatial analyses of porous lesions as well as targeting different tissues or molecules for biomolecular identification may improve the archaeological understanding of malaria.

Retrospective Study of Bone-TB in Oman: 2002-2019

Objective: Little information is available about the etiology, pathophysiology, risk factors, and epidemiologic features of Bone Tuberculosis (Bone-TB). In this work, we present the epidemiological data about the Bone-TB in the Sultanate of Oman.

Methods: Retrospectively, we identified and assessed those patients who were diagnosed with Bone-TB between January 2002 and December 2019 at Khoula Hospital. The following data were collected: demographics, clinical presentation, anatomical location, diagnosis, and treatment of the Bone-TB.

Results: During the study period, 115 cases of Bone-TB were diagnosed. Males were affected more than females (57.4% and 42.6%, respectively). About 30% of Bone-TB cases were primary diagnosed in other organs particularly the lungs and then after disseminated to the bone. However, the Bone-TB was detected in hip, leg, hand, shoulder, and skull bones, the most detected Bone-TB was in spine (66% of cases). After vaccination the Bacillus Calmette–Guérin (BCG) strains were identified in the bones of eight babies. Tubercle bacilli were detected by Acid-Fast Stain (AFS) in 59% of cases, and the rest of cases were confirmed using polymerase chain reaction (PCR) tests. There are two used treatment regimens, with 12.4% relapse. The gastrointestinal tract (GIT) disturbances were the most related side effects. The resistance has been detected to pyrazinamide in six cases, rifampicin in three cases, and isoniazid, streptomycin and kanamycin were detected in one case.

Conclusion: The most predominant Bone-TB cases were spine-TB that were mainly disseminated from the lungs. AFS failed to detect tubercle bacilli in 40% of cases. There is no statistical significance in relapse between the used two regimens. The death was predominant among skull-TB cases.

Insights from ancient DNA analysis of Egyptian human mummies: clues to disease and kinship

The molecular Egyptology field started in the mid-eighties with the first publication on the ancient DNA (aDNA) analysis of an Egyptian mummy. Egypt has been a major interest for historians, archeologists, laymen as well as scientists. The aDNA research on Egyptian biological remains has been fueled by their abundance and relatively well-preserved states through artificial mummification and by the advanced analytical techniques. Early doubts of aDNA integrity within the Egyptian mummies and data authenticity were later abated with studies proving successfully authenticated aDNA retrieval. The current review tries to recapitulate the published studies presenting paleogenomic evidence of disease diagnosis and kinship establishment for the Egyptian human remains. Regarding disease diagnosis, the prevailing literature was on paleogenomic evidence of infectious diseases in the human remains. A series of reports presented evidence for the presence of tuberculosis and/or malaria. In addition, there were solitary reports of the presence of leprosy, diphtheria, bacteremia, toxoplasmosis, schistosomiasis and leishmaniasis. On the contrary, paleogenomic evidence of the presence of rare diseases was quite scarce and mentioned only in two articles. On the other hand, kinship analysis of Egyptian human remains, including that of Tutankhamen, was done using both mitochondrial DNA sequences and nuclear DNA markers, to establish family relationships in four studies. It is clear that the field of molecular Egyptology is still a largely unexplored territory. Nevertheless, the paleogenomic investigation of Egyptian remains could make significant contributions to biomedical sciences (e.g. elucidation of coevolution of human host-microbe interrelationship) as well as to evidence-based archeology.

Tuberculosis in medieval and early modern Denmark: A paleoepidemiological perspective

Millions of people worldwide have sickened and died from tuberculosis in recent centuries. Yet for most of human existence, the impact of tuberculosis on society is largely unknown. It is, indeed, unknowable without methods suitable for estimating disease prevalence in skeletal samples. Here such a procedure is applied to medieval and early modern Danish skeletons, and it shows how disease prevalence varied with differences in socioeconomic conditions. The approach is based on sensitivity and specificity estimates from modern skeletons. To augment our understanding of tuberculosis in Danish history, 713 adult skeletons were examined, all from Ribe. Tuberculosis increased from 17% to 40% in the medieval to early modern periods in Ribe. Low status (29%) people were more likely to contract the disease than those of high status (10%). The general model, derived from the modern expression of tuberculosis, fits the early modern sample better than it does the medieval skeletons. Differences in the model's fit indicate the skeletal expression changed over time. Notably, rib lesions increased in frequency from the medieval to early modern periods. The approach developed here can provide insights into host-pathogen relationships and disease expression in future work with tuberculosis and other diseases that affect the skeleton.

The association between skeletal lesions and tuberculosis diagnosis using a probabilistic approach

Sensitivity and specificity estimates for 18 skeletal lesions were generated from modern skeletons for future paleoepidemiological analyses of tuberculosis prevalence in archaeological samples. A case-control study was conducted using 480 skeletons from 20^th century American skeletal collections. One-half of the skeletons were documented tuberculosis cases (Terry Collection). The remaining age and sex-matched skeletons were controls (Bass Collection). The association between 18 candidate skeletal lesions and tuberculosis was established by comparing lesion distributions in case and control groups. Lesion indicators at six locations - visceral surface of ribs, ventral vertebral bodies, lateral part of ilium, acetabular fossa, iliac auricular surface, and ulna olecranon process - occurred significantly more often among cases than in controls, and were associated with one another. The most useful indicator proved to be a bony reaction on ventral thoracic and lumbar vertebral bodies. Its presence means a 53.3% probability of a true tuberculosis diagnosis. Because of the nature of the reference sample - 20th century American cases - sensitivity and specificity estimates will better estimate disease prevalence in archaeological samples from cultural settings where pulmonary tuberculosis predominated. The general approach of this proof-of-concept study is applicable to other diseases that occur commonly and affect bone.

Screening methods for detection of ancient Mycobacterium tuberculosis complex fingerprints in next-generation sequencing data derived from skeletal samples

BACKGROUND

Recent advances in ancient DNA studies, especially in increasing isolated DNA yields and quality, have opened the possibility of analysis of ancient host microbiome. However, such pitfalls as spurious identification of pathogens based on fragmentary data or environmental contamination could lead to incorrect epidaemiological conclusions. Within the Mycobacterium genus, Mycobacterium tuberculosis complex members responsible for tuberculosis share up to ∼99% genomic sequence identity, while other more distantly related Mycobacteria other than M. tuberculosis can be causative agents for pulmonary diseases or soil dwellers. Therefore, reliable determination of species complex is crucial for interpretation of sequencing results.

RESULTS

Here we present a novel bioinformatical approach, used for screening of ancient tuberculosis in sequencing data, derived from 28 individuals (dated 4400-4000 and 3100-2900 BC) from central Poland. We demonstrate that cost-effective next-generation screening sequencing data (∼20M reads per sample) could yield enough information to provide statistically supported identification of probable ancient disease cases.

CONCLUSIONS

Application of appropriate bioinformatic tools, including an unbiased selection of genomic alignment targets for species specificity, makes it possible to extract valid data from full-sample sequencing results (without subjective targeted enrichment procedures). This approach broadens the potential scope of palaeoepidaemiology both to older, suboptimally preserved samples and to pathogens with difficult intrageneric taxonomy.

Vertebral infection in a male individual buried in the monastic cemetery (Cemetery 2) at Ghazali (ca. 670-1270 CE), northern Sudan

PURPOSE/RESEARCH QUESTION

This article examines pronounced osteoblastic-osteolytic vertebral lesions in a middle adult male (Ghz-2-033), from the Christian Nubian monastic settlement of Ghazali (ca. 670-1270 CE), Sudan, to explore their potential etiology.

METHODS

Morphological assessments of sex and age were undertaken in conjunction with macroscopic and radiological methods of assessment for the skeletal lesions documented.

RESULTS

Macroscopic assessment of Ghz-2-033 identified mixed osteoblastic-osteolytic lesions in L2-L3 with minor foci in T12-L1, while radiological assessment identified no further lesions. This paleopathological analysis considers tuberculosis, brucellosis, pyogenic intervertebral disc infection, neoplastic conditions, and mycotic infections as potential etiologies.

CONCLUSIONS

Tuberculosis is the most probable etiology for the lesions observed. This assessment is based on the morphology of the lesions in conjunction with the known confined living quarters at Ghazali and the presence of tuberculosis vectors (i.e. cattle) in the region.

CONTRIBUTIONS TO KNOWLEDGE/ORIGINALITY/VALUE

This brief communication contributes original data documenting the presence of tubercular lesions in a monk buried at the Christian Nubian monastery of Ghazali. On a broader level this study contributes to regional and temporal paleopathological dialogues regarding interactions with pathogens in Christian Nubian monastic contexts.

LIMITATIONS FOR THIS STUDY

The potentiality of co-infection with other pathogens (e.g. brucellosis, Staphylococcus) with similar macromorphological traits in skeletal remains cannot be entirely discounted.

SUGGESTIONS FOR FURTHER RESEARCH

The use of biomolecular analyses may help to clarify the potential presence of tuberculosis in individual Ghz-2-033.

Iron Acquisition in Mycobacterium tuberculosis

The highly contagious disease tuberculosis (TB) is caused by the bacterium Mycobacterium tuberculosis (Mtb), which has been evolving drug resistance at an alarming rate. Like all human pathogens, Mtb requires iron for growth and virulence. Consequently, Mtb iron transport is an emerging drug target. However, the development of anti-TB drugs aimed at these metabolic pathways has been restricted by the dearth of information on Mtb iron acquisition. In this Review, we describe the multiple strategies utilized by Mtb to acquire ferric iron and heme iron. Mtb iron uptake is a complex process, requiring biosynthesis and subsequent export of Mtb siderophores, followed by ferric iron scavenging and ferric-siderophore import into Mtb. Additionally, Mtb possesses two possible heme uptake pathways and an Mtb-specific mechanism of heme degradation that yields iron and novel heme-degradation products. We conclude with perspectives for potential therapeutics that could directly target Mtb heme and iron uptake machineries. We also highlight how hijacking Mtb heme and iron acquisition pathways for drug import may facilitate drug transport through the notoriously impregnable Mtb cell wall.

Bone Diagenesis and its Implication for Disease Diagnosis: The Relevance of Bone Microstructure Analysis for the Study of Past Human Remains

When bone is exposed to the burial environment it may experience structural changes induced by multiple agents. The study of postmortem alterations is important to differentiate decomposition phenomena from normal physiological processes or pathological lesions, as well as to assess bone tissue quality. Microscopy is of great utility to evaluate the integrity of bone microstructure and it provides significant data on long-term bone decomposition. A total of 18 human bone sections (eight archeological and ten retrieved from an identified skeletal collection) were selected for analysis under plane light and polarized light. The aim of this exploratory study was to analyze the impact of diagenesis and taphonomy on the bone microstructure, as well as on the differential diagnosis of pathological conditions. The results showed that the microscopy approach to bone tissues contributed materially as an aid in the detailed description of the main diagenetic changes observed. It showed that gross inspection does not provide a realistic assessment of bone tissue preservation, which can impact in the characterization of lesions present and subsequent disease diagnosis. Therefore, researchers should continue to consider the application of histological techniques if the aim is to comprehend tissue integrity and its association with decomposition or disease.

Molecular studies on ancient M. tuberculosis and M. leprae: methods of pathogen and host DNA analysis

Humans have evolved alongside infectious diseases for millennia. Despite the efforts to reduce their incidence, infectious diseases still pose a tremendous threat to the world population. Fast development of molecular techniques and increasing risk of new epidemics have resulted in several studies that look to the past in order to investigate the origin and evolution of infectious diseases. Tuberculosis and leprosy have become frequent targets of such studies, owing to the persistence of their molecular biomarkers in ancient material and the characteristic skeletal lesions each disease may cause. This review examines the molecular methods used to screen for the presence of M. tuberculosis and M. leprae ancient DNA (aDNA) and their differentiation in ancient human remains. Examples of recent studies, mainly from Europe, that employ the newest techniques of molecular analysis are also described. Moreover, we present a specific approach based on assessing the likely immunological profile of historic populations, in order to further elucidate the influence of M. tuberculosis and M. leprae on historical human populations.

Post mortem DNA degradation of human tissue experimentally mummified in salt

Mummified human tissues are of great interest in forensics and biomolecular archaeology. The aim of this study was to analyse post mortem DNA alterations in soft tissues in order to improve our knowledge of the patterns of DNA degradation that occur during salt mummification. In this study, the lower limb of a female human donor was amputated within 24 h post mortem and mummified using a process designed to simulate the salt dehydration phase of natural or artificial mummification. Skin and skeletal muscle were sampled at multiple time points over a period of 322 days and subjected to genetic analysis. Patterns of genomic fragmentation, miscoding lesions, and overall DNA degradation in both nuclear and mitochondrial DNA was assessed by different methods: gel electrophoresis, multiplex comparative autosomal STR length amplification, cloning and sequence analysis, and PCR amplification of different fragment sizes using a damage sensitive recombinant polymerase. The study outcome reveals a very good level of DNA preservation in salt mummified tissues over the course of the experiment, with an overall slower rate of DNA fragmentation in skin compared to muscle.

Palaeopathology and genes: investigating the genetics of infectious diseases in excavated human skeletal remains and mummies from past populations

The aim of this paper is to review the use of genetics in palaeomicrobiology, and to highlight the importance of understanding past diseases. Palaeomicrobiology is the study of disease pathogens in skeletal and mummified remains from archaeological contexts. It has revolutionarised our understanding of health in the past by enabling a deeper knowledge of the origins and evolution of many diseases that have shaped us as a species. Bacterial diseases explored include tuberculosis, leprosy, bubonic plague, typhoid, syphilis, endemic and epidemic typhus, trench fever, and Helicobacter pylori. Viral diseases discussed include influenza, hepatitis B, human papilloma virus (HPV), human T-cell lymphotrophic virus (HTLV-1) and human immunodeficiency virus (HIV). Parasitic diseases investigated include malaria, leishmaniasis, Chagas' disease, roundworm, whipworm, pinworm, Chinese liver fluke, fleas and lice. Through a better understanding of disease origins and their evolution, we can place into context how many infectious diseases are changing over time, and so help us estimate how they may change in the future.

Detection of microorganisms in granulomas that have been formalin-fixed: review of the literature regarding use of molecular methods

Granuloma is an organized aggregate of immune cells that under the microscope appear as epithelioid macrophages. A granuloma can only be diagnosed when a pathologist observes this type of inflammation under the microscope. If a foreign body or a parasite is not observed inside the granuloma, stains for acid-fast bacilli and fungi are ordered since mycobacteria and fungi are frequently the cause of this type of inflammation. It is calculated that 12 to 36% of granulomas do not have a specific etiology and many have wondered if with new molecular methods we could reduce this number. This paper will summarize the frequently known causes of granulomas and will present the recent literature regarding the use of molecular techniques on tissue specimens and how these have helped in defining causative agents. We will also briefly describe new research regarding formation and function of granulomas and how this impacts our ability to find an etiologic agent.

Bone and joint tuberculosis

INTRODUCTION

Bone and joint tuberculosis has increased in the past two decades in relation with AIDS epidemics.

MATERIAL AND METHODS

A literature review of bone and joint tuberculosis, focusing on Pott's disease.

RESULTS

Bone and joint TB comprises a group of serious infectious diseases whose incidence has increased in the past two decades, especially in underdeveloped countries, in part due to the AIDS epidemic. Tuberculous spinal infections should be suspected in patients with an insidious, progressive history of back pain and in individuals from an endemic area, especially when the thoracic vertebrae are affected and a pattern of bone destruction with relative disc preservation and paravertebral and epidural soft tissue masses are observed. Atypical tuberculous osteoarticular manifestations involving the extraspinal skeleton, a prosthetic joint, or the trochanteric area, and nontuberculous mycobacterial infections should be considered in favorable epidemiological contexts. Surgery combined with prolonged specific antituberculous chemotherapy is mainly indicated in patients with neurological manifestations or deformities, and provides satisfactory results in most cases.

CONCLUSIONS

Spinal tuberculosis is still a relative common extra spinal manifestation of spinal tuberculosis that requires a high degree of suspicion in order to avoid neurological complications and need of surgery.

Evolution of human tuberculosis: a systematic review and meta-analysis of paleopathological evidence

Tuberculosis is a re-emerging disease and is a major problem in both developing and developed countries today. An estimated one third of the world's population is infected and almost two million people die from the disease each year. Bone lesions occur in 3-5% of active tuberculosis cases and can be used to diagnose the disease in ancient skeletal remains. A meta-analysis was conducted on 531 palaeopathological tuberculosis cases from 221 sites (7250 BCE to 1899) on all continents for the purpose of testing two hypotheses; (1) the frequency of bone lesions does not change through time and (2) the distribution of lesions throughout the skeleton does not change over time. The frequency of bone lesions was found to significantly decrease over time (P<0.05). The distribution of bone lesions was found to change from mainly spinal in earlier time periods to include more cases in other regions of the skeleton (long bones, joints, hands, feet) in later time periods. This difference in distribution was evaluated using a Chi-squared test and found to be significant (P<0.01). These findings are an important addition to the current knowledge of the evolution of the disease and the Mycobacterium tuberculosis.

Magnetic resonance evaluation of tubercular lesion in spine

PURPOSE

Information on Magnetic Resonance (MR) features of active and healed lesions in tuberculosis (TB) spine are lacking. We evaluated MRI findings in active and healed proven TB spine to establish the diagnostic features.

MATERIALS AND METHOD

Forty-nine consecutive spinal TB patients (20 male; 29 female) diagnosed clinicoradiologically and/or on histopathology, Fine Needle Aspiration Cytology (FNAC), bacteriology, or Polymerase Chain Reaction (PCR) were enrolled. Pretreatment MR scans were reviewed for diagnostic features, and eight-month follow-up MR scans were reviewed for healing changes.

RESULTS

Cervical spine (n = 6), dorsal spine (n = 14), and lumbar spine (n = 29) were affected. Fourteen had paraplegia. Mean vertebrae involved were 2.61 on X-ray with a total of 128 vertebrae (VB) and 3.2 on MRI (range, 2-15) with 161 VB. The lesions were more extensive on MRI (34.7%) than appreciated on X-ray. The disc was preserved partially or fully in 88.2% of instances. End plate erosions (159/161 VB), lost VB height (94/161), exudative lesion (158/161), granular lesion (3/161), pre and paravertebral collections (49/49 cases), marrow oedema (161/161), discitis (98%), epidural involvement (107/161), epidural spread (100/161), and subligamentous spread (156/161) were observed. Canal encroachment (10-90%) was seen in 37 cases. Mean motor and sensory scores with greater than 50% canal encroachment were 87/100 and 156/168, respectively. Cord oedema was observed in 11 cases (eight with neural deficit and three cases without). Cord atrophy was seen in one case each before and after treatment. A total of 83% of patients had a combination of paravertebral collections, marrow oedema, subligamentous and epidural extension, endplate erosions and discitis. On healing (n = 20), complete resolution of marrow oedema and collections, fatty replacement of bone marrow and resolution of cord signal intensity were observed.

CONCLUSION

The marrow oedema, preservation of disc space, subligamentous extension of abscess, septate paravertebral abscess, epidural extension, endplate erosions and discitis were consistently observed in 83% cases of TB spine on MRI.

Tuberculosis of the spine: a fresh look at an old disease

The dismal outcome of tuberculosis of the spine in the pre-antibiotic era has improved significantly because of the use of potent antitubercular drugs, modern diagnostic aids and advances in surgical management. MRI allows the diagnosis of a tuberculous lesion, with a sensitivity of 100% and specificity of 88%, well before deformity develops. Neurological deficit and deformity are the worst complications of spinal tuberculosis. Patients treated conservatively show an increase in deformity of about 15 degrees . In children, a kyphosis continues to increase with growth even after the lesion has healed. Tuberculosis of the spine is a medical disease which is not primarily treated surgically, but operation is required to prevent and treat the complications. Panvertebral lesions, therapeutically refractory disease, severe kyphosis, a developing neurological deficit, lack of improvement or deterioration are indications for surgery. Patients who present with a kyphosis of 60 degrees or more, or one which is likely to progress, require anterior decompression, posterior shortening, posterior instrumented stabilisation and anterior and posterior bone grafting in the active stage of the disease. Late-onset paraplegia is best prevented rather than treated. The awareness and suspicion of an atypical presentation of spinal tuberculosis should be high in order to obtain a good outcome. Therapeutically refractory cases of tuberculosis of the spine are increasing in association with the presence of HIV and multidrug-resistant tuberculosis.

Auto-fluorescence emitted from the cell residues preserved in human tissues of medieval Korean mummies

As a significant association has been established between residual ancient DNA (aDNA) and histological preservation, the morphological identification or confirmation of preserved cell residue in ancient tissues would greatly facilitate aDNA studies and enhance the definitiveness of their conclusions. However, morphological differentiation of cell residue from other tissue structures has always been difficult, even for experienced histologists, due to the severe degradation of cells over long burial durations. In the present study, using a fluorescence microscopy equipped with a specific type of filter set (excitation filter, 510-550 nm; dichroic mirror, 570 nm; emission filter, approximately 590 nm), we found that certain structures in well-preserved mummified tissues emitted auto-fluorescence. Those structures were actually cell residues (e.g. fragmented DNA), laser capture microdissection and Quantifiler kit analysis having shown that preservation of nuclear DNA correlates with auto-fluorescence emission in laser capture microdissection-captured areas. Detection of auto-fluorescence could be an effective means of identifying cell residues in ancient tissue, enabling selection of the well-preserved samples necessary in successful aDNA studies.

Tuberculosis and leprosy in perspective

Two of humankind's most socially and psychologically devastating diseases, tuberculosis and leprosy, have been the subject of intensive paleopathological research due to their antiquity, a presumed association with human settlement and subsistence patterns, and their propensity to leave characteristic lesions on skeletal and mummified remains. Despite a long history of medical research and the development of effective chemotherapy, these diseases remain global health threats even in the 21st century, and as such, their causative agents Mycobacterium tuberculosis and M. leprae, respectively, have recently been the subject of molecular genetics research. The new genome-level data for several mycobacterial species have informed extensive phylogenetic analyses that call into question previously accepted theories concerning the origins and antiquity of these diseases. Of special note is the fact that all new models are in broad agreement that human TB predated that in other animals, including cattle and other domesticates, and that this disease originated at least 35,000 years ago and probably closer to 2.6 million years ago. In this work, we review current phylogenetic and biogeographic models derived from molecular biology and explore their implications for the global development of TB and leprosy, past and present. In so doing, we also briefly review the skeletal evidence for TB and leprosy, explore the current status of these pathogens, critically consider current methods for identifying ancient mycobacterial DNA, and evaluate coevolutionary models.

Paleopathology of human tuberculosis and the potential role of climate

Both origin and evolution of tuberculosis and its pathogens (Mycobacterium tuberculosis complex) are not fully understood. The paleopathological investigation of human remains offers a unique insight into the molecular evolution and spread including correlative data of the environment. The molecular analysis of material from Egypt (3000-500 BC), Sudan (200-600 AD), Hungary (600-1700 AD), Latvia (1200-1600 AD), and South Germany (1400-1800 AD) urprisingly revealed constantly high frequencies of tuberculosis in all different time periods excluding significant environmental influence on tuberculosis spread. The typing of various mycobacteria strains provides evidence for ancestral M. tuberculosis strains in Pre- to early Egyptian dynastic material (3500-2650 BC), while typical M. africanum signatures were detected in a Middle Kingdom tomb (2050-1650 BC). Samples from the New Kingdom to Late Period (1500-500 BC) indicated modern M. tuberculosis strains. No evidence was seen for M. bovis in Egyptian material while M. bovis signatures were first identified in Siberian biomaterial dating 2000 years before present. These results contraindicates the theory that M. tuberculosis evolved from M. bovis during early domestication in the region of the "Fertile Crescent," but supports the scenario that M. tuberculosis probably derived from an ancestral progenitor strain. The environmental influence of this evolutionary scenario deserves continuing intense evaluation.

PCR diagnostics of Mycobacterium tuberculosis in historic human long bone remains from 18th century burials in Kaiserebersdorf, Austria

Background

In the present pilot study we applied recently published protocols for detecting Mycobacterium tuberculosis in human remains. We screened long bones from an 18^th century cemetery and skulls from the anatomical "Weisbach collection" (19^th century). In addition, besides the study of abundance of tuberculosis in inmates of the poorhouse itself, we were interested to test whether in this particular instance tuberculosis can be identified from cortical bones, which are rarely affected by tuberculosis, but mostly better preserved than the vertebral bodies or epiphyses.

Method

The DNA extractions from the bone samples were obtained following established ancient DNA protocols. Subsequently extracts were subjected to a series of PCR amplifications using primer pairs published previously [1,2]. PCR products of the expected size were subsequently sequenced.

Results

Only primers targeting the repetitive IS6110 insertion sequence yielded PCR products of appropriate size. In one sample only (skull sample WB354 of the "Weisbach collection") sequence analysis revealed an authentic M. tuberculosis sequence that matched to a reference sequence from GenBank.

Conclusion

With a variety of established PCR approaches we failed to detect M. tuberculosis DNA in historic human femurs from an 18^th century cemetery relating to a poor house in Kaiserebersdorf, Austria. Our data may indicate that in this particular case, thoracic or lumbar vertebrae, i.e. bones that are severely affected by the disease, would be more suitable for molecular diagnostics than long bones. However, the unpredictable state of DNA preservation in bones from museum collections does not allow any general recommendation of any type of bone.

Evidence for complex interactions of stress-associated regulons in an mprAB deletion mutant of Mycobacterium tuberculosis

Two-component systems are important constituents of bacterial regulatory networks. Results of this investigation into the role of the MprAB two-component system of Mycobacterium tuberculosis indicate that it is associated with the regulation of several stress-responsive regulons. Using a deletion mutant lacking portions of the response regulator, MprA, and the histidine kinase, MprB, it was demonstrated by real-time PCR, primer extension analyses and DNA microarrays that MprAB activates sigma factor genes sigE and sigB, under SDS stress and during exponential growth. SDS-inducible, MprA-dependent transcriptional start points were identified for mprA, sigE and sigB, and variations in distance between these points and MprA-binding sites suggest that MprA is involved in different mechanisms of promoter activation. Although most of the SigE regulon was downregulated in the deletion mutant, the cluster of genes Rv1129c, Rv1130 and Rv1131, which is associated with growth in monocytes, was upregulated in the deletion mutant under SDS stress, and this upregulation was dependent upon atmospheric growth conditions. Multiple stress-associated genes of the DosR, SigD and IdeR regulons were also upregulated in the deletion mutant, during exponential growth and/or in the presence of SDS. Surprisingly, the deletion mutant had increased resistance to SDS compared to the parental strain, and enhanced growth in human peripheral blood monocytes, characteristics which may result from a loss of repression of stress-associated genes.

Mycobacterial osteomyelitis and arthritis

Physicians can expect to see more mycobacterial bone and joint disease in North America as a result of increased travel, immigration, and use of immunosuppressive medications. The first step in treating infections caused by these organisms is to consider the diagnosis early in the course of illness. Long-standing untreated mycobacterial infections typically cause significant bone destruction and loss of function. The treatment of mycobacterial bone and joint infection requires prolonged antibiotic therapy, often in conjunction with surgical intervention, particularly for spinal tuberculosis.

On the Origin of American Tuberculosis

After more than a century of debate, it is now firmly established that tuberculosis existed in the New World before the arrival of Columbus. What is not yet known is how or when, exactly, the infection reached the Americas, how it spread from one continent to the other, and whether the pre-Columbian infection was caused by Mycobacterium tuberculosis or Mycobacterium bovis.