Publication date: Jul 09, 2023
Time-to-Detection (TTD) in culture on liquid media is inversely correlated to bacillary load and should be a contributing factor for assessing tuberculosis transmission. We wanted to assess if TTD was a better alternative than smear-status to estimate transmission risk. From October 2015 to June 2022, we studied retrospectively a cohort of index cases (IC) with pulmonary tuberculosis (tuberculosis disease TD) from which samples were was culture-positive before treatment. We studied the correlation between TTD and contact-positivity of IC-contacts: contact positivity cp, was defined as cp=1 (CP group) in case of TD or LTI (latent tuberculosis infection) in at least one screened contact of an IC, and cp=0 otherwise (CN group). Univariate and multivariable analysis (logistic regression) were done. Of the 185 IC, 122 were included, generating 846 contact-cases of which 705 were assessed. A transmission event (LTI ot TD) was identified in 193 contact-cases (transmission rate: 27%). At Day 9, 66% and 35% of the IC had their sample positive in culture for CP and CN groups respectively. Age and TTD ≤ 9 days were independent criteria of CP (OR 0. 97, CI [0. 95 – 0. 98], p=0. 002 and OR 3. 52, CI [1. 59 – 7. 83], p=0. 001, respectively). TTD was a more discriminating parameter than smear-status to evaluate transmission risk of an IC with pulmonary tuberculosis. Therefore, TTD should be considered in the contact-screening strategy around an IC.
| Concepts | Keywords |
|---|---|
| Cohort | contact-screening |
| June | index cases |
| Td | Mycobacterium tuberculosis |
| Tuberculosis | smear-status |
| time-to-detection | |
| transmission |
Semantics
| Type | Source | Name |
|---|---|---|
| disease | MESH | latent tuberculosis infection |
| disease | MESH | pulmonary tuberculosis |
| drug | DRUGBANK | Tropicamide |
| pathway | KEGG | Tuberculosis |
| disease | MESH | tuberculosis |