This is a notification list documenting new bacterial names and taxonomic combinations published in volume 50, part 4 of the International Journal of Systematic and Evolutionary Microbiology (IJSEM) in 2000. The list serves as an official registry to assist the bacteriology community in recognizing newly described species, subspecies, genera, and families, as well as nomenclatural corrections and taxonomic reclassifications. The procedure was established by the Judicial Commission to provide priority documentation based on publication order. The notification includes 40 distinct taxonomic entries spanning diverse bacterial groups, including Gram-positive cocci (Streptococcus, Staphylococcus), Gram-negative bacteria (Xanthomonas, Pseudomonas, Sphingomonas), and various anaerobes and thermophiles. Several entries involve nomenclatural corrections addressing gender agreement issues in Latin names. The list encompasses newly established genera such as Actinoalloteichus, Anaerovorax, and Thermacetogenium, alongside numerous new species descriptions from multiple bacterial families. This standardized notification process ensures transparency and accessibility of new bacterial nomenclature within the scientific community.

Key findings

• Forty new bacterial taxa were formally described or reclassified in IJSEM volume 50, part 4, spanning diverse phylogenetic groups
• Multiple nomenclatural corrections were published addressing Latin gender agreement in previously established species names (Xenorhabdus, Anaerorhabdus, Desulforhabdus)
• New genera established include Actinoalloteichus, Anaerovorax, Catenibacterium, Thermacetogenium, Denitrovibrio, and Acidisphaera
• The notification list serves as an official registry ensuring priority and recognition of new bacterial taxa by the international microbiology community