Core profile of volatile organic compounds related to growth of Mycobacterium avium subspecies paratuberculosis - A comparative extract of three independent studies

PLoS One. 2019 Aug 15;14(8):e0221031. doi: 10.1371/journal.pone.0221031. eCollection 2019.

Abstract

Analysis of volatile organic compounds (VOC) derived from bacterial metabolism during cultivation is considered an innovative approach to accelerate in vitro detection of slowly growing bacteria. This applies also to Mycobacterium avium subsp. paratuberculosis (MAP), the causative agent of paratuberculosis, a debilitating chronic enteritis of ruminants. Diagnostic application demands robust VOC profiles that are reproducible under variable culture conditions. In this study, the VOC patterns of pure bacterial cultures, derived from three independent in vitro studies performed previously, were comparatively analyzed. Different statistical analyses were linked to extract the VOC core profile of MAP and to prove its robustness, which is a prerequisite for further development towards diagnostic application. Despite methodical variability of bacterial cultivation and sample pre-extraction, a common profile of 28 VOCs indicating cultural growth of MAP was defined. The substances cover six chemical classes. Four of the substances decreased above MAP and 24 increased. Random forest classification was applied to rank the compounds relative to their importance and for classification of MAP versus control samples. Already the top-ranked compound alone achieved high discrimination (AUC 0.85), which was further increased utilizing all compounds of the VOC core profile of MAP (AUC 0.91). The discriminatory power of this tool for the characterization of natural diagnostic samples, in particular its diagnostic specificity for MAP, has to be confirmed in future studies.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Mycobacterium avium subsp. paratuberculosis / growth & development*
  • Paratuberculosis / diagnosis
  • Paratuberculosis / metabolism*
  • Paratuberculosis / microbiology
  • Ruminants / microbiology*
  • Volatile Organic Compounds / analysis
  • Volatile Organic Compounds / metabolism*

Substances

  • Volatile Organic Compounds

Grants and funding

This work received funding by the Deutsche Forschungsgemeinschaft (https://www.dfg.de/) for this study, grant no. RE 1098/4-1, RE 1098/4-2 (PR), SCHU 1960/4-1 and SCHU 1960/4-2 (JS). The funder had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript.