biostudies-literatureUnknown71(9)Pallen MJbiotechnology and biological sciences research councilmedical research councilBiotechnology and Biological Sciences Research CouncilThe status <i>Candidatus</i> was introduced to bacterial taxonomy in the 1990s to accommodate uncultured taxa defined by analyses of DNA sequences. Here I review the strengths, weaknesses, opportunities and threats (SWOT) associated with the status <i>Candidatus</i> in the light of a quarter century of use, twinned with recent developments in bacterial taxonomy and sequence-based taxonomic discovery. Despite ambiguities as to its scope, philosophical objections to its use and practical problems in implementation, the status <i>Candidatus</i> has now been applied to over 1000 taxa and has been widely adopted by journals and databases. Although lacking priority under the International Code for Nomenclature of Prokaryotes, many <i>Candidatus</i> names have already achieved <i>de facto</i> staInternational journal of systematic and evolutionary microbiologyhttps://www.ebi.ac.uk/biostudies/studies/S-EPMC8549269biostudies-literatureThe status <i>Candidatus</i> for uncultured taxa of <i>Bacteria</i> and <i>Archaea</i>: SWOT analysis.PMC8549269BBS/E/F/000PR10351MR/T030062/1BB/R012504/1BBS/E/F/00044414Pallen MJfalseThe status <i>Candidatus</i> for uncultured taxa of <i>Bacteria</i> and <i>Archaea</i>: SWOT analysis.The status <i>Candidatus</i> was introduced to bacterial taxonomy in the 1990s to accommodate uncultured taxa defined by analyses of DNA sequences. Here I review the strengths, weaknesses, opportunities and threats (SWOT) associated with the status <i>Candidatus</i> in the light of a quarter century of use, twinned with recent developments in bacterial taxonomy and sequence-based taxonomic discovery. Despite ambiguities as to its scope, philosophical objections to its use and practical problems in implementation, the status <i>Candidatus</i> has now been applied to over 1000 taxa and has been widely adopted by journals and databases. Although lacking priority under the International Code for Nomenclature of Prokaryotes, many <i>Candidatus</i> names have already achieved <i>de facto</i> sta2021-01-01T00:00:00Z2021 Sep2025-04-20T01:11:05.462Z2025-02-19T01:26:21.599ZS-EPMC85492693451636810.1099/ijsem.0.005000