Early stationary phase culture supernatant accelerates growth of sputum cultures collected after initiation of anti-tuberculosis treatment

Abstract

We investigated the effect of Mycobacterium tuberculosis culture supernatant added to sputum cultures collected during the first 8 weeks of anti-tuberculosis treatment. With ongoing treatment duration, time to culture positivity decreased significantly in supernatant-enriched cultures, possibly due to stimulation of dormant or slowly metabolizing M. tuberculosis cells.

Development of an In Vitro Assay for Detection of Drug-Induced Resuscitation-Promoting-Factor-Dependent Mycobacteria

“…Tuberculosis is a worldwide health threat, and recent global efforts have been directed to the development of novel agents to eradicate M. tuberculosis and especially its nonreplicating forms, which are believed to be responsible for prolonged treatment and disease relapse. Populations of nonreplicating, Rpf-dependent, and SN-dependent cells were recently identified in patient sputum samples and were apparently enriched in treated samples ( 16 , 28 ), leading to our hypothesis that antituberculosis drugs may induce Rpf dependency. Accordingly, we investigated whether mycobacteria from growing cultures could become NP or SN dependent after exposure to antimicrobial agents.…”

Phenotypically Adapted Mycobacterium tuberculosis Populations from Sputum Are Tolerant to First-Line Drugs

“…Determining the duration of treatment for tuberculosis is problematic and is not aided by molecular tests, such as the XpertMTB/RIF test ( 26 ). However, M. tuberculosis culture supernatant has been shown to accelerate growth of mycobacteria from treated sputum samples ( 27 ). Assessment of sputum samples from patients during tuberculosis treatment using Rpf-supplemented medium may provide information relevant to determining endpoints for therapy with minimal risk of relapse.…”

The In Vivo Environment Accelerates Generation of Resuscitation-Promoting Factor–Dependent Mycobacteria

“…However, exposure of mycobacteria to murine serum did not stimulate Rpf dependency, suggesting that a yet unknown combination of environmental conditions not identified (or present) in in vitro experiments or certain immune factors may trigger transition to the Rpfdependent state. Our findings have important implications for the diagnosis of tuberculosis (14,15) and development of models for testing the bactericidal activity of novel drugs. The presence of a high number of Rpf-dependent bacteria in vivo must be taken into account in the design of drugs for the treatment of tuberculosis, and compounds should also be tested for activity against Rpf-dependent forms.…”