Spot sputum samples are at least as good as early morning samples for identifying Mycobacterium tuberculosis

Strain structure analysis of Mycobacterium tuberculosis circulating among HIV negative, positive and drug resistant TB patients attending chest clinics in Western Kenya

BACKGROUND

Despite global tuberculosis (TB) interventions, the disease remains one of the major public health concerns. Kenya is ranked 15th among 22 high burden TB countries globally.

METHODS

A cross-sectional study was conducted in Western Kenya, which comprises 10 counties. A multistage sampling method was used where a single sub-county was randomly selected followed by sampling two high volume health facility from each sub-county. Identification of spoligotype profiles and their family distribution and lineage level were achieved by comparison with SITVIT database.

RESULTS

Lineage distribution pattern revealed that the most predominant lineage was CAS 220 (39.8%) followed by Beijing 128 (23.1%). The other lineages identified were T, LAM, H, X, S and MANU which were quantified as 87 (15.7%), 67 (12.1%), 16 (2.8%), 10 (1.8%), 8 (1.4%) and 5 (0.9%) respectively. CAS and Beijing strains were the most predominant lineage in both HIV negative and positive TB patients. The Beijing lineage was also the most predominant in resistant M. tuberculosis strains as compared to wild type. A total of 12 (2.0%) were orphaned M. tuberculosis strains which were spread across all the 10 counties of the study site. In multivariate logistic regression adjusting for potential cofounders three potential risk factors were significant. HIV status (OR = 1.52, CI = 0.29-3.68 and P value of 0.001), Alcohol use (OR = 0.59, CI = 0.43-3.12 and P-value =0.001) and cross border travel (OR = 0.61, CI = 0.49-3.87 and P value = 0.026). Most M. tuberculosis clinical isolates showed genetic clustering with multivariate logistic regression indicating three potential risk factors to clustering. HIV status (OR = 1.52, CI = 0.29-3.68 and P value of 0.001), Alcohol use (OR = 0.59, CI = 0.43-3.12 and P-value =0.001) and cross border travel (OR = 0.61, CI = 0.49-3.87 and P value = 0.026).

CONCLUSION

There exist diverse strains of M. tuberculosis across the 10 counties of Western Kenya. Predominant distribution of clustered genotype points to the fact that most TB cases in this region are as a result of resent transmission other than activation of latent TB.

Building sustainable clinical trial sites in Sub-Saharan Africa through networking, infrastructure improvement, training and conducting clinical studies: The PanACEA approach

INTRODUCTION

The Pan-African Consortium for the Evaluation of Anti-Tuberculosis Antibiotics (PanACEA) was designed to build tuberculosis (TB) trial capacity whilst conducting clinical trials on novel and existing agents to shorten and simplify TB treatment. PanACEA has now established a dynamic network of 11 sub-Saharan clinical trial sites and four European research institutions.

OBJECTIVES

In 2011, a capacity development program, funded by the European & Developing Countries Clinical Trials Partnership (EDCTP), was launched with four objectives, aiming at strengthening collaborating TB research sites to reach the ultimate goal of becoming self-sustainable institutions: networking; training; conducting clinical trials; and infrastructure scaling-up of sites.

METHODS

Assessment in six sub-Saharan TB-endemic countries (Gabon, Kenya, South Africa, Tanzania, Uganda and Zambia) were performed through a structured questionnaire, site visits, discussion with the PanACEA consortium, setting of milestones and identification of priorities and followed-up with evaluations of each site. The results of this needs-based assessment was then translated into capacity development measures.

RESULTS

In the initial phase, over a four-year period (March 2011 - June 2014), the programme scaled-up six sites; conducted a monitoring training program for 11 participants; funded five MSc and four PhD students, fostering gender balance; conducted four epidemiological studies; supported sites to conduct five Phase II studies and formed a sustainable platform for TB research (panacea-tb.net).

CONCLUSION

Our experience of conducting TB clinical trials within the PanACEA programme environment of mentoring, networking and training has provided a sound platform for establishing future sustainable research centres. Our goal of facilitating emergent clinical TB trial sites to better initiate and lead research activities has been mostly successful.

Why health system diagnosis delay among tuberculosis patients in Illubabor, Oromia region, South West Ethiopia? A qualitative study

BACKGROUND

The main target of tuberculosis control and prevention is to detect incident cases as quickly as possible and also to prevent the occurrence of disease. It is also the responsibility of the health facility to screen the contacts, identifying children for prophylactic therapy. However, the target is difficult to meet due to issues within health facilities that cause health system diagnostic delays. Despite this, there is no information explored why health system diagnostic delays among tuberculosis patients.

METHOD

A qualitative study was conducted by using different data collection methods and sources. Seventeen DOT providers, five laboratory professionals, six program managers, and seven Tuberculosis patients were interviewed. In addition, 22 governmental health facilities were observed for the availability of resources. Data obtained from the in-depth interviews was transcribed, coded, categorized, and thematized manually.

RESULT

Health system Diagnosis delays reasons were related with sample collection procedures, poor competency of health professionals, in addition to absences or scarcity of health professionals, medical products, and basic infrastructure. We found 18 health facilities without skilled personnel in the OPD, 7 health facilities with a broken microscope, and almost all health facilities without a separate room for sputum examination. Furthermore, 12 (54.5%) and 14 (63.6%) health facilities lacked access to water and electric power, respectively.

CONCLUSION

Many reasons for TB diagnosis delays have been identified in the study area. Poor competence of health workers and scarcity of resources were identified. Depending on the finding, we suggest strengthening the health workers' training. Concrete strategies need to be designed to retain professionals. Training on human resource planning and budget preparation is needed for front-line managers. Managers have to work on the maintenance of diagnostic tools and facilitate transportation. The rural health facilities need to use another alternative power source.

Association between serum PGE2 levels and degree of acid-fast bacilli positivity in sputum of pulmonary tuberculosis patients

Background

Mycobacterium tuberculosis that infected apoptotic macrophages is triggered by PGE₂. Apoptosis suppresses the growth of Mycobacterium tuberculosis bacteria, which is shown in the results of acid-fast bacilli (AFB) in the sputum that becomes a marker of the number of bacteria.

Objective

Analyzing the association between serum PGE₂ levels and the positivity of AFB in the sputum of tuberculosis patients.

Methods

A cross-sectional study was carried out from August 2019–July 2020. Serum PGE₂ levels and AFB levels in sputum were collected from participants. Data analysis used the Chi-square test and Spearman's correlation with p < 0.05.

Results

The average participants’ serum PGE₂ levels were 446.37 ± 510.27 pg/ml, with a median value of 216.95 pg/ml. Most participants had normal serum PGE₂ levels (62.9%). Most participants had a high positivity of AFB in sputum (58.1%). Analysis of the association between serum PGE₂ levels and the degree of AFB positivity in sputum obtained r = −0.036 and p-value = 0.780.

Conclusion

There is a weak negative association between serum PGE₂ levels and the degree of AFB positivity in sputum but not statistically significant.

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Serum PGE₂ levels of tuberculosis patients tend to be normal even though acid-fast bacilli (AFB) values are high.

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Most of the new and recurrent cases of pulmonary tuberculosis patients had normal PGE₂ levels.

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Serum PGE₂ levels have a negative association with AFB value.

Early-Morning vs Spot Posterior Oropharyngeal Saliva for Diagnosis of SARS-CoV-2 Infection: Implication of Timing of Specimen Collection for Community-Wide Screening

Background

Posterior oropharyngeal saliva is increasingly recognized as a valid respiratory specimen for SARS-CoV-2 diagnosis. It is easy to collect and suitable for community-wide screening. The optimal timing of collection is currently unknown, and we speculate that an early-morning specimen before oral hygiene and breakfast would increase the diagnostic yield.

Methods

Posterior oropharyngeal saliva was collected at 5 different time points within the same day from 18 patients with previously confirmed SARS-CoV-2 infection by molecular testing. Cycle threshold (Ct) values were compared.

Results

There was an overall trend of lower Ct values from specimens collected in the early morning, with a gradual decrease of viral load towards nighttime, but reaching statistical significance only when compared with the specimens collected at bedtime. Eight out of 13 subjects had a higher viral load in the early morning than the rest of the 4 time points (before lunch, before teatime at 3 pm, before dinner, before bedtime).

Conclusions

The result suggests a diurnal variation of viral shedding from the upper respiratory tract with a trend showing higher viral load in the early morning. For community screening purposes, posterior oropharyngeal saliva could be taken throughout the day, but preferably in the early morning to maximize the yield.

Use of GeneXpert MTB/RIF on a single pooled sputum specimen to exclude pulmonary tuberculosis among hospital inpatients placed in respiratory isolation

BACKGROUND

Patients with suspected pulmonary tuberculosis (PTB) are usually placed in respiratory isolation awaiting three sputum smear microscopy results for acid-fast bacilli (3AFB). GeneXpert MTB/RIF (Xpert) on a pooled sample from two sputa may allow for more rapid de-isolation.

OBJECTIVES

To compare the sensitivity and negative predictive value (NPV) of Xpert performed on a single pooled sputum sample ('pooled Xpert') to 3AFB, in order to exclude PTB in patients placed in respiratory isolation.

METHODS

Hospital inpatients in respiratory isolation for possible PTB were enrolled prospectively. Three expectorated sputum samples were obtained for smear microscopy. Two of the same samples had 0.5 ml removed from each and pooled for pooled Xpert. The diagnostic accuracy of pooled Xpert and 3AFB were assessed and compared to liquid culture at 8 weeks as the reference standard.

RESULTS

Of 56 participants, nine (16.1%) were diagnosed with PTB. Compared to liquid culture, pooled Xpert had a sensitivity of 88.9% (95% confidence interval (CI) 57-99%) and NPV of 97.9% (95% CI 89-99%). 3AFB had a sensitivity of 66.7% (95% CI 35-88%) and NPV of 93.5% (95% CI 83-98%).

CONCLUSIONS

A single pooled Xpert was non-inferior to 3AFB, with a strong trend towards greater sensitivity and better NPV. These findings support the use of a single pooled Xpert as an effective rapid screening approach for ruling out PTB in low incidence settings. Its value in high incidence settings and optimal combination with smear microscopy and culture warrant further evaluation.

Bringing patient-centered tuberculosis diagnosis into the light of day

In 2015, the WHO End TB Strategy laid out ambitious goals to dramatically reduce tuberculosis (TB) deaths, incidence, and catastrophic costs through research, bold new strategies, and patient-centered care. In this commentary, recent evidence on sputum collection strategies for smear microscopy is reviewed, and the argument is made that redesigning smear microscopy as a patient-centered service offers the only realistic and widely available strategy to advance TB diagnostic care towards the initial End TB Strategy goals laid out for 2025. Finally, the successful adoption of same-day sputum smear microscopy as a model for patient-centered TB care is suggested to be synergistic with and to form part of the scale-up of new TB diagnostic tools.Please see related article: https://bmcmedicine.biomedcentral.com/articles/10.1186/s12916-017-0947-9.