Clinico-pathological features of tuberculosis due to Mycobacterium tuberculosis Uganda genotype in patients with tuberculous lymphadenitis: a cross sectional study

A pilot study on the genetic diversity of Mycobacterium tuberculosis complex strains from tuberculosis patients in the Littoral region of Cameroon

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The Xpert MTB/RIF provides a rapid MDR detection and management of TB patients.

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The Cameroon family is the predominant genotype in the Littoral region of Cameroon.

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The UgandaI sublineage is likely associated with RIF resistance in the study area.

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The mapping of the UgandaI sublineage is essential for MDR control in the country.

Background

The re-emergence of tuberculosis (TB) worldwide, compounded by multi-drug resistance (MDR) of the causative agents constitutes a major challenge to the management of the disease. Rapid diagnosis and accurate strain identification are pivotal to the control of the disease. This pilot study investigated the genetic diversity of Mycobacterium tuberculosis complex (MTBC) strains from TB patients in the Littoral region of Cameroon as well as their resistance to rifampicin (RIF).

Patients and methods

This was a cross sectional hospital-based study carried out between January and December 2017 and including 158 isolates from sputum smear positive individuals [105 (66.5%) males and 53 (33.5%) females]. Sputum samples were tested using Xpert MTB/RIF, followed by culture on Lowenstein–Jensen medium. Isolates were further subjected to molecular characterization using IS6110 typing, deletion analysis and spoligotyping.

Results

Thirteen (8.8%) of the 147 isolates with susceptibility results available were resistant to RIF. Drug resistance occurred in 5/50 (10%) female compared to 8/97 (8.2%) male (OR, 0.81; 0.25–2.62; p = 0.764), and there was no significant difference across the age ranges (p = 0.448). On the other hand, RIF resistance was associated (OR, 0.18, 95%CI, 0.05–0.69; p = 0.023) with previously treated patients [(4/14 (28.6%)] compared to new ones [9/133 (6.8%)]. The 150 identified lineages included among others 54 (36%) Cameroon, 18 (12%) UgandaI, 32 (21.3%) Haarlem, 17 (11.3%) Ghana, 9(6%) West African 1, 7(4.7%) Delhi/CAS, 4 (2.7%) LAM and 3 (2%) UgandaII. Of the 150 isolates, the major cluster was the Cameroon SIT 61, with 43(28.7%) isolates. Six (35.3%) of the 17 UgandaI sub-lineage were RIF resistant (OR, 9.58; 95%CI, 2.74–33.55, p = 0.001).

Conclusion

The cosmopolitan Littoral region presents with a wide Mycobacterium tuberculosis (MTB) strains diversity and the UgandaI sub-lineage likely associated with RIF resistance. Understanding the spread of this clade through surveillance will enhance TB control in the region.

Epidemiology of tuberculous lymphadenitis in Africa: A systematic review and meta-analysis

INTRODUCTION

Tuberculous lymphadenitis is the most frequent form of extra-pulmonary TB (EPTB) and accounts for a considerable proportion of all EPTB cases. We conducted a systematic review of articles that described the epidemiological features of TBLN in Africa.

METHODS

Any article that characterized TBLN cases with respect to demographic, exposure and clinical features were included. Article search was restricted to African countries and those published in English language irrespective of publication year. The articles were retrieved from the electronic database of PubMed, Scopus, Cochrane library and Lens.org. Random effect pooled prevalence with 95% CI was computed based on Dersimonian and Laird method. To stabilize the variance, Freeman-Tukey double arcsine root transformation was done. The data were analyzed using Stata 14.

RESULTS

Of the total 833 articles retrieved, twenty-eight articles from 12 African countries fulfilled the eligibility criteria. A total of 6746 TBLN cases were identified. The majority of the cases, 4762 (70.6%) were from Ethiopia. Over 77% and 88% of identified TBLN were cervical in type and naïve to TB drugs. Among the total number of TBLN cases, 53% were female, 68% were in the age range of 15-44 years, 52% had a history of livestock exposure, 46% had a history of consuming raw milk/meat and 24% had history of BCG vaccination. The proportion of TBLN/HIV co-infection was much lower in Ethiopia (21%) than in other African countries (73%) and the overall African estimate (52%). Fever was recorded in 45%, night sweating in 55%, weight loss in 62% and cough for longer than two weeks in 32% of the TBLN cases.

CONCLUSIONS

TBLN was more common in females than in males. The high prevalence of TBLN in Ethiopia did not show directional correlation with HIV. Population based prospective studies are warranted to better define the risk factors of TBLN in Africa.

Impact of Mycobacterium tuberculosis complex lineages as a determinant of disease phenotypes from an immigrant rich moderate tuberculosis burden country

Background

Growing evidences suggested that the Mycobacterium tuberculosis complex (MTBC) lineages can determine the clinical outcome of pulmonary and extra-pulmonary tuberculosis. However, limited data only available revealing such association of bacterial genotypes and clinical phenotypes from immigrant rich countries.

Methods

A multicenter study has been carried out on a collection of 2092 (1003 extrapulmonary and 1089 pulmonary) MTBC isolates. Genotyping of all the isolates were carried out by spoligotyping and 24 loci based MIRU-VNTR typing.

Results

Demographically domination of young Saudi nationals (61.4%) and men (61.2%) were found in this cohort. Lymph nodes (62.4%) and gastrointestinal sites (16.7%) were the most common anatomical sites of infection. The predominant lineages were Delhi/CAS (26.9%), EAI (14.2%) and Ghana (9.9%). Mycobacterium africanum type I and II were reported for the first time in the country among extrapulmonary cases. ‘Ancestral’ lineages M.bovis (OR-5.22; 95% CI-2.23-8.22, p- < 0.001) and Delhi/CAS (OR-0.57; 95% CI-0.411-0.734, p- < 0.001) were directly associated with lymph node tuberculosis and gastrointestinal tuberculosis (M. bovis-OR-0.33; 95% CI-0.085-0.567, p-0.001 and Delhi/CAS-OR-1.87; 95% CI-1.22-2.53, p- < 0.001) respectively. Among the ‘Modern’ lineages, EAI showed significant association to central nervous system tuberculosis (OR-1.98; 95% CI-0.76-3.19, p-0.04) and Uganda-I to gastrointestinal tuberculosis (OR-2.41; 95% CI-0.77-4.06, p-0.02).

Conclusions

The findings substantially contribute to the emerging evidences that MTBC lineages influence disease phenotypes and epidemiological consequences.

Electronic supplementary material

The online version of this article (10.1186/s12931-018-0966-x) contains supplementary material, which is available to authorized users.

HIV-1 and the Mycobacterium tuberculosis granuloma: A systematic review and meta-analysis

Infection with HIV-1 greatly increases the risk of active tuberculosis (TB). Although hypotheses suggest HIV-1 disrupts Mycobacterium tuberculosis (Mtb) granuloma function, few studies have examined this directly. The objective of this study was to determine what evidence exists about the effect HIV-1 co-infection has upon Mtb granulomas. A systematic search of PubMed, Web of Science, and Medline up to 20 March 2015 was conducted, to identify studies comparing Mtb-infected tissue from HIV-1 infected and uninfected persons, or HIV-1 infected persons with stratified peripheral CD4 T cell (pCD4) counts. We summarized findings that focused on how HIV-1 changes granuloma formation, bacterial presence, cellular composition, and cytokine production. Nineteen studies with a combined sample size of 899 persons were included. Although studies frequently were limited by variable or inadequately described definitions of outcomes and analytical methods, HIV-1 was found to be associated with increased bacillary load within Mtb-infected tissue. Reductions in pCD4 counts within co-infected persons associated with both poorer granuloma formation and higher bacterial load. The high degree of heterogeneity among studies combined with experimental limitations made it difficult to conclusively support previously published and prevalent hypotheses about HIV-1/Mtb co-infection granulomas. To elucidate the validity of these hypotheses we have described areas that can be improved in future studies in order to clarify the influence HIV-1 co-infection has upon the Mtb granuloma.

A single-nucleotide-polymorphism real-time PCR assay for genotyping of Mycobacterium tuberculosis complex in peri-urban Kampala

Background

Accurate and high-throughput genotyping of Mycobacterium tuberculosis complex (MTBC) may be important for understanding the epidemiology and pathogenesis of tuberculosis (TB). In this study, we report the development of a LightCycler® real-time PCR single-nucleotide-polymorphism (LRPS) assay for the rapid determination of MTBC lineages/sublineages in minimally processed sputum samples from TB patients.

Method

Genotyping analysis of 70 MTBC strains was performed using the Long Sequence Polymorphism-PCR (LSP-PCR) technique and the LRPS assay in parallel. For targeted sequencing, 9 MTBC isolates (three isolates per MTBC lineage) were analyzed for lineage-specific single nucleotide polymorphisms (SNPs) in the following three genes to verify LRPS results: Rv004c for MTB Uganda family, Rv2962 for MTB lineage 4, and Rv0129c for MTB lineage 3. The MTBC lineages present in 300 smear-positive sputum samples were then determined by the validated LRPS method without prior culturing.

Results

The LSP-PCR and LRPS assays produced consistent genotyping data for all 70 MTBC strains; however, the LSP-PCR assay was 10-fold less sensitive than the LRPS method and required higher DNA concentrations to successfully characterize the MTBC lineage of certain samples. Targeted sequencing of genes containing lineage-specific SNPs was 100 % concordant with the genotyping results and provided further validation of the LRPS assay. Of the 300 sputum samples analyzed, 58 % contained MTBC from the MTBC-Uganda family, 27 % from the MTBC lineage 4 (excluding MTBC Uganda family), 13 % from the MTBC lineage 3, and the remaining 2 % were of indeterminate lineage.

Conclusion

The LRPS assay is a sensitive, high-throughput technique with potential application to routine genotyping of MTBC in sputum samples from TB patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-015-1121-7) contains supplementary material, which is available to authorized users.

Predominance of Uganda genotype of Mycobacterium tuberculosis isolated from Ugandan patients with tuberculous lymphadenitis

Background

In Uganda, the emerging Uganda genotype of Mycobacterium tuberculosis is the most common cause of pulmonary tuberculosis (PTB), and accounts for up to 70 % of isolates. Extrapulmonary TB (EPTB) is less studied in Uganda.

Methods

Molecular characterization using deletion analysis and spoligotyping was performed on 121 M. tuberculosis isolates from lymph node fine needle biopsy aspirates of Ugandan patients with tuberculous lymphadenitis. The evolutionary relationships and worldwide distribution of the spoligotypes were analyzed.

Results

Mycobacterium tuberculosis was the only cause of EPTB in this study. The T2 sublineage was the most predominant lineage and the Uganda genotype was the dominant genotype. There were 54 spoligotype patterns among the 121 study isolates. The dominant spoligotypes were shared international types (SIT) SIT420, SIT53, SIT 135, SIT 128 and SIT590 in descending order. All but SIT420 were previously reported in pulmonary TB in this setting. The phylogenetic analysis showed a long descendant branch of spoligotypes belonging to the T2-Uganda sublineage containing specifically SITs 135, 128 and 420.

Conclusion

In most cases, the spoligotypes were similar to those causing PTB, but the Uganda genotype was found to be less common in EPTB than previously reported for PTB in Uganda. The phylogenetic analysis and the study of the worldwide distribution of clustered spoligotypes indicate an ongoing evolution of the Uganda genotype, with the country of Uganda at the center of this evolution.

Electronic supplementary material

The online version of this article (doi:10.1186/s13104-015-1362-y) contains supplementary material, which is available to authorized users.