Clinical trial NCT04968886: TuBerculosis Viability Interregional Study and Agreement on Biological Tests
Official title: Multicenter Prospective Evaluation of Rapid Viability Tests for Mycobacterium Tuberculosis to Improve the Follow-up of Tuberculosis Patients and Guide Isolation Measures
Study type: OBSERVATIONAL
Overall status: UNKNOWN
Conditions: Tuberculosis, Pulmonary
Keywords: Hospital infection control
Isolation
Treatment response
Tuberculosis
Viability stain
Lead sponsor: Assistance Publique - Hôpitaux de Paris
Sponsor class: OTHER
First posted: 2021-07-20
Enrollment: 104
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Observational model: COHORT
Time perspective: PROSPECTIVE
Sampling method: NON_PROBABILITY_SAMPLE
Study population: Smear-positive pulmonary tuberculosis patients.

Brief summary: The objective of the present study is to confirm in a multicentric study the utility of our viability test in large cohort of smear-positive pulmonary tuberculosis patients under treatment and to determine if the test could help physicians to discontinue isolation measures in hospital setting.

Detailed description: When patients with pulmonary tuberculosis (TB) are hospitalized for diagnosis and treatment, isolation measures are mandatory in order to prevent transmission. Recommendations are to maintain isolation until patients are no more infectious, which is ascertained when cultures of respiratory specimens become negative (culture conversion). After administration of antibiotics, the average time to culture conversion is one month for patients with drug-susceptible TB, but 5%-30% cases require more than two months and up to 6 months can be required for multiresistant (MDR)-TB.

Microscopic examination of bacilli in respiratory samples is mainly used as a surrogate marker but because bacilli staining does not differentiate alive from dead bacilli, the interpretation of positive smears is misleading. After 1-2 months of treatment, bacilli can be considered dead while they are still alive and isolation measures are thus erroneously discontinued. Conversely, bacilli can be considered viable while they have already been killed by the treatment and patients kept inadequately in isolation.

To overcome the misleading results, attempts have been made to develop viability biomarkers for Mycobacterium tuberculosis (Mtb), the agent of tuberculosis. Studies using RNA or DNA gave convincing results but their cost is not affordable in most part of the world. Those using fluorescein probes are easiest but studies have shown either conflicting results, or have been evaluated only for a short period of time after initiation of therapy.

Thus, we evaluated a fluorescent staining able to differentiate dead bacilli from alive, which was previously used for detection of industrial environmental pathogens - the Live/Dead® BacLight™ Bacterial viability test (Invitrogen, Biocentric, France). Briefly, the test permits to visualize the bacteria using SYTO-9 and propidiumiodide (PI) fluorescent dyes, which both bind to DNA but penetrate specifically cytoplasmic membrane: SYTO-9 penetrates all bacilli, either viable or not, whereas the PI penetrates only in cells with damaged membrane. Consequently, the viable bacteria are impermeable to PI and only fluoresced due to SYTO-9 appearing green under the fluorescent microscope, whereas dead bacteria are marked by both fluorescent dyes and appear red.

We firstly adapted the kit to mycobacteriology and assessed, in in vitro experiments, the concordance of the test with the culture results. Then, we showed in an observational prospective study its accurateness to predict culture results in patients undergoing antituberculous therapy: the viability test correctly predicted all culture-positive samples in the first two months after treatment.

The objective of the present study is to confirm in a multicentric study the utility of our viability test in large cohort of smear-positive pulmonary tuberculosis patients under treatment and to determine if the test could help physicians to discontinue isolation measures in hospital setting.

Since the test is quick (less than 1 h for the test versus a median of 23 days for culture) and easy to perform, it would be useful to help physicians to maintain isolation in clinical settings while avoiding unnecessary cultures. Since the test is also cheap (\<1 € for reagents) this issue could be particularly valuable in countries with limited resources and where cultures are unavailable.

Eligibility criteria: Inclusion Criteria:

* Age from 18 years old
* Patient put on anti-tuberculosis treatment for pulmonary tuberculosis with at least one positive ME
* Information given on the study and the right to oppose

Exclusion Criteria:

* Refusal of participation
* People unable to understand the information, In accordance with article 11218 of the public health code,
* people not affiliated with Health Insurance,
* pregnant or breastfeeding women patients under legal protection can be included in a non-interventional study (type 3).

Primary outcomes:
measure: Result of the viability test (positive or negative) compared to culture results (reference test). - The reference test will be considered as positive (C+) if Mtb are grown on solid or liquid media et negative (C-) if the cultures remain sterile after 42
timeFrame: 12 months
Secondary outcomes:
measure: Evaluate the diagnostic performance of the molecular test for the viability of tuberculosis bacilli
timeFrame: 12 months
measure: Study the correlation between the quantitative results of viability tests and the quantitative results of the culture
timeFrame: 12 months
measure: Evaluate the potential benefit of viability tests for the patient and the hospital over the duration of isolation and the time to discharge from hospital
timeFrame: 12 months
measure: Describe the cohort of patients hospitalized for pulmonary tuberculosis with positive microscopic examination in the 10 participating centers
timeFrame: 12 months
Other outcomes:
Locations:
Study officials:
affiliation: Public Assistance of Paris Hospitals (APHP)
name: Benjamin WYPLOSZ, Ph
role: PRINCIPAL_INVESTIGATOR
References: