Origin of tuberculosis in the Paleolithic predicts unprecedented population growth and female resistance

Sex-based tuberculosis mortality in Newfoundland, 1900-1949: Implications for populations in transition

OBJECTIVE

During the second epidemiological transition, tuberculosis (TB) is one disease that declined substantially enough to reduce all-cause mortality. Sex-based differences in TB mortality may reveal an important dimension of population health transitions between the urbanizing and rural regions of Newfoundland.

MATERIALS AND METHODS

For the island of Newfoundland, yearly age-standardized sex-based TB mortality rates were calculated using individual death records from 1900 to 1949 (n = 30 393). Multiple linear regression models predict the relative rates (RR) of sex-based mortality and the absolute difference between males and females while controlling for time and region (the urbanizing Avalon Peninsula or rural Newfoundland). Multiple linear regression models also predict the median age at death from TB while controlling for time, region, and sex to assess if TB was shifting to an older adult disease compared to those typically afflicted in ages 20-44.

RESULTS

Female TB mortality was relatively and absolutely higher than males; additionally, RR and absolute differences between male and female mortality were significantly lower in rural Newfoundland than the Avalon Peninsula. Median age at death for males was significantly higher than females, and differences in median age at death increased over time.

DISCUSSION

The historically high prevalence of TB throughout Newfoundland, including domestic, social, and public health responsibilities of women, likely contributed to increased exposure and transmission, leading to higher observed mortality. Sex-based TB outcomes should be considered in the discussion of the progression of the epidemiological transition as dynamic inequalities that do not necessarily fit contemporary generalizations of sex-based TB epidemiology.

Pathogenicity and virulence of Mycobacterium tuberculosis

Mycobacterium tuberculosis (Mtb) is the causative agent of tuberculosis, an infectious disease with one of the highest morbidity and mortality rates worldwide. Leveraging its highly evolved repertoire of non-protein and protein virulence factors, Mtb invades through the airway, subverts host immunity, establishes its survival niche, and ultimately escapes in the setting of active disease to initiate another round of infection in a naive host. In this review, we will provide a concise synopsis of the infectious life cycle of Mtb and its clinical and epidemiologic significance. We will also take stock of its virulence factors and pathogenic mechanisms that modulate host immunity and facilitate its spread. Developing a greater understanding of the interface between Mtb virulence factors and host defences will enable progress toward improved vaccines and therapeutics to prevent and treat tuberculosis.

The paleopathology and paleoepidemiology of Upper paleolithic tuberculosis: Review of evidence and hypotheses

Molecular phylogeny work has shown that tuberculosis is ancient human-adapted infection predating the Neolithic period. They also show that the Upper Paleolithic is a key period of emergence of the MTB complex strains, contemporary with the exit of modern man from Africa. Despite the richness of Upper Paleolithic sites in Eurasia and the relative abundance of human remains, the only proven case of Paleolithic tuberculosis has been described so far date from the Azilian, a culture of the European Final Paleolithic, which is more recent than the ancient Neolithic sites of the Near East, area that currently hold the record for the oldest paleopathological evidence of tuberculosis. The purpose of this review is to present evidence for the existence of tuberculosis in the Paleolithic and to list hypotheses explaining the weak demonstrative contribution of paleopathology for pre-Neolithic periods.

Mycobacterium abscessus VapC5 toxin potentiates evasion of antibiotic killing by ribosome overproduction and activation of multiple resistance pathways

Mycobacterium abscessus (Mab) infections are inexplicably intractable to clearing after aggressive and lengthy treatment regimens. Here we discovered that acquisition of a single toxin-antitoxin system enables Mab to activate a phenotypic switch that enhances survival upon treatment with current first-line antibiotics. This switch is tripped when the VapC5 toxin inactivates tRNASerCGA by cleavage at only one site within its anticodon, leading to growth arrest. Concomitant tRNASerCGA depletion then reprograms the transcriptome to favor synthesis of proteins naturally low in the cognate Ser UCG codon including the transcription factor WhiB7 and members of its regulon as well as the ribosomal protein family. This programmed stockpiling of ribosomes is predicted to override the efficacy of ribosome-targeting antibiotics while the growth arrest phenotype attenuates antibiotics targeting cell wall synthesis. In agreement, VapC5 increases Mab persister formation upon exposure to amikacin and the next-generation oxazolidinone tedizolid (both target ribosomes) or cefoxitin (inhibits cell wall synthesis). These findings expand the repertoire of genetic adaptations harnessed by Mab to survive assaults intended to eradicate it, as well as provide a much-needed framework for selection of shorter and more efficacious alternate treatment options for Mab infections using currently available antimicrobials whose targets are not confounded by VapC5.

Drug Resistance in Tuberculous Lymphadenitis: Molecular Characterization

Background

Drug-resistant tuberculosis (TB) epidemic in high-TB-incidence countries, particularly Ethiopia, remains a significant challenge. As a result, we investigated the drug resistance, common gene mutation, and molecular characterization of mycobacterial isolates from patients with suspected tuberculous lymphadenitis (TBLN). Methodology. A cross-sectional study of 218 FNA samples from TBLN patients inoculated on Lowenstein-Jensen media was carried out. The culture isolates were identified as MTB by polymerase chain reaction (PCR) and the difference-9 (RD9) test region. In addition, the GenoType MTBDRplus assay tested the first and second-line MTB drugs, and the spoligotyping strain-dependent polymorphism test was determined.

Results

Among the 50 culture-positive isolates, 14% (7/50) had drug resistance caused by a gene mutation. Out of these, 4 (8%) isolates were mono-resistant to isoniazid drug, which is caused by a gene mutation in katG in the region of interrogated at codon 315 in the amino acid sequence of S315T1, and 3 (6%) isolates were resistant to both rifampicin and isoniazid drugs. The mutation was observed for katG (at codon 315 with a change in the sequence of amino acid S315T) and rpoB (at codon 530-533 with a change in the sequence of amino acid S531L (S450L)) genes. The most prevalent spoligotypes were orphan and SIT53 strains.

Conclusion

The predominance of INH mono-resistance poses a critical risk for the potential development of MDR-TB, as INH mono-resistance is a typical pathway to the occurrence of MDR-TB. The orphan and SIT53 (T) strains were the most common in the study area, and a drug-resistant strain caused by a common gene mutation could indicate the transmission of clonal-resistant strains in the community.

A Comparative Study on Visual Detection of Mycobacterium tuberculosis by Closed Tube Loop-Mediated Isothermal Amplification: Shedding Light on the Use of Eriochrome Black T

Loop-mediated isothermal amplification is a promising candidate for the rapid detection of Mycobacterium tuberculosis. However, the high potential for carry-over contamination is the main obstacle to its routine use. Here, a closed tube LAMP was intended for the visual detection of Mtb to compare turbidimetric and two more favorable colorimetric methods using calcein and hydroxy naphthol blue (HNB). Additionally, a less studied dye (i.e., eriochrome black T (EBT)) was optimized in detail in the reaction for the first time. Mtb purified DNA and 30 clinical specimens were used to respectively determine the analytical and diagnostic sensitivities of each method. The turbidimetric method resulted in the best analytical sensitivity (100 fg DNA/reaction), diagnostic sensitivity and specificity (100%), and time-to-positivity of the test (15 min). However, this method is highly prone to subjective error in reading the results. Moreover, HNB-, calcein-, and EBT-LAMP could respectively detect 100 fg, 1 pg, and 1 pg DNA/reaction (the analytical sensitivities) in 30, 15, and 30 min, while the diagnostic sensitivity and specificity were respectively 93.3% and 100% for them all. Interestingly, EBT-LAMP showed the lowest potential for subjective error in reading the results. This report helps judiciously choose the most appropriate visual method, taking a step forward toward the field applicability of LAMP for the detection of Mtb, particularly in resource-limited settings.

The Origin and Maintenance of Tuberculosis Is Explained by the Induction of Smear-Negative Disease in the Paleolithic

Is it possible that the origin of Mycobacterium tuberculosis (Mtb) infection was around 70,000 years before the common era? At that time Homo sapiens was just another primate species with discrete growth and a very low-density geographic occupation. Therefore, it is difficult to understand the origin of a highly virulent obligate human pathogen. We have designed a new SEIR model (TBSpectr) that allows the differentiation of smear-positive and -negative tuberculosis. The model reconciles currently accepted growth rates for the Middle Paleolithic (0.003%/year) and Neolithic (0.1%/year). The obtained data link the origin of Mtb infection in the Middle Paleolithic to the induction of smear-negative TB, and reveal that its persistence required interrelations among hunter–gatherer groups, while the risk of human extinction was negligible. It also highlights the number of people infected per case and the fast progression to disease for Mtb infection maintenance, as well as the link between poor health in the Neolithic with the increased incidence of more severe forms of TB (smear-positive). In conclusion, our data support the origin of TB as a well-tolerated, highly persistent disease, even in low-density populations, showing the difficulty of its eradication and highlighting the necessity for providing better health conditions to humans to reduce its severity.

Diabetes and tuberculosis: A syndemic complicated by COVID-19

Tuberculosis (TB) is the leading cause of infectious mortality in the world, affecting mainly developing countries (DC), while diabetes (DM) is one of the most prevalent chronic diseases.

This review analyzes the fact that diabetes is currently an important risk factor for developing TB, also presenting more complicated TB, more relapses and higher mortality. The DCs and the fourth world of the large cities are those with the highest incidence of TB and an increase in DM, which will make it difficult to control tuberculosis disease. At the same time, the COVID-19 pandemic is complicating the management of both diseases due to the difficulty of access to control and treatment and the worsening of socioeconomic inequalities. It is necessary to establish a bidirectional screening for TB and DM and promote recommendations for the joint management of both diseases.

How rare is rare? A literature survey of the last 45 years of paleopathological research on ancient rare diseases

OBJECTIVE

This paper aims to provide a quantitative estimation of the representation of diseases defined as rare today in the bioarchaeological literature and to outline the reasons for this.

MATERIALS

A 45-year bibliometric study of publications in seven bioarchaeological journals, along with two journals and editorial groups of broader scientific focus.

METHODS

Analyses of distribution patterns of the search hits and diachronic trends for achondroplasia, autosomal-dominant osteopetrosis, osteogenesis imperfecta, and osteopoikilosis, compared to those for tuberculosis as control measure of coverage.

RESULTS

Studies of ancient rare diseases (ARD) are mostly published as case reports in specialized journals and their number did not benefit from the introduction of biomolecular studies. The higher frequency of cases of achondroplasia suggests that not all rare diseases are equally under-represented.

CONCLUSIONS

Rare diseases are still largely under-represented in bioarchaeological literature. Their marginality likely results from a combination of taphonomic, methodological and public visibility factors.

SIGNIFICANCE

This article is the first attempt to provide a quantitative assessment of the under-representation of ARD and to outline the factors behind it.

LIMITATIONS

Rare diseases are an etiologically heterogeneous group. The number of surveyed journals and articles, as well as targeted diseases might be limiting factors.

SUGGESTIONS FOR FURTHER RESEARCH

Increasing collection and dissemination of data on ARD; opening a wide-ranging debate on their definition; implementation of biomolecular studies.

Diabetes and tuberculosis: a syndemic complicated by COVID-19

Tuberculosis (TB) is the leading cause of infectious mortality in the world, affecting mainly developing countries (DC), while diabetes (DM) is one of the most prevalent chronic diseases. This review analyzes the fact that diabetes is currently an important risk factor for developing TB, also presenting more complicated TB, more relapses and higher mortality. The DCs and the fourth world of the large cities are those with the highest incidence of TB and an increase in DM, which will make it difficult to control tuberculosis disease. At the same time, the COVID-19 pandemic is complicating the management of both diseases due to the difficulty of access to control and treatment and the worsening of socioeconomic inequalities. It is necessary to establish a bidirectional screening for TB and DM and promote recommendations for the joint management of both diseases.