| Spezies | Risiko- gruppe | Bemer- kungen | Status |
| Xanthobacter | |||
| Xanthobacter agilis | 1 | ||
| Xanthobacter aminoxidans | 1 | ||
| Xanthobacter autotrophicus | 1 | ||
| Xanthobacter flavus | 1 | ||
| Xanthobacter tagetidis | 1 | ||
| Xanthobacter viscosus | 1 | ||
| Xanthomarina | |||
| Xanthomarina gelatinilytica | 1 | neu | |
| Xanthomonas | |||
| Xanthomonas albilineans | 1 | p | |
| Xanthomonas alfalfae subsp. alfalfae | 1 | p | |
| Xanthomonas alfalfae subsp. citrumelonis | 1 | p | |
| Xanthomonas ampelina → Xylophilus ampelinus | |||
| Xanthomonas arboricola | 1 | p2 | |
| Xanthomonas axonopodis | 1 | p2 | |
| Xanthomonas bromi | 1 | p | |
| Xanthomonas campestris | 1 | p | |
| Xanthomonas cassavae | 1 | p | |
| Xanthomonas citri → Xanthomonas citri subsp. citri | |||
| Xanthomonas citri subsp. citri (Xanthomonas citri) | 1 | p | |
| Xanthomonas citri subsp. malvacearum | 1 | p | |
| Xanthomonas codiaei | 1 | p | |
| Xanthomonas cucurbitae | 1 | p | |
| Xanthomonas cynarae | 1 | p | |
| Xanthomonas dyei | 1 | p | |
| Xanthomonas euvesicatoria | 1 | p | |
| Xanthomonas floridensis | 1 | neu | |
| Xanthomonas fragariae | 1 | p2 | |
| Xanthomonas fuscans subsp. aurantifolii – synonym: Xanthomonas citri subsp. citri | |||
| Xanthomonas fuscans subsp. fuscans – synonym: Xanthomonas citri subsp. citri | |||
| Xanthomonas gardneri | 1 | p | |
| Xanthomonas hortorum | 1 | p | |
| Xanthomonas hyacinthi | 1 | p | |
| Xanthomonas maliensis | 1 | neu | |
| Xanthomonas maltophilia → Stenotrophomonas maltophilia | |||
| Xanthomonas melonis | 1 | p | |
| Xanthomonas nasturtii | 1 | p2 | neu |
| Xanthomonas oryzae | 1 | p2 | |
| Xanthomonas perforans | 1 | p | |
| Xanthomonas phaseoli | 1 | p | |
| Xanthomonas pisi | 1 | p | |
| Xanthomonas populi | 1 | p | |
| Xanthomonas sacchari | 1 | p | |
| Xanthomonas theicola | 1 | p | |
| Xanthomonas translucens | 1 | p2 | |
| Xanthomonas vasicola | 1 | p | |
| Xanthomonas vesicatoria | 1 | p2 | |
| Xenophilus | |||
| Xenophilus aerolatus | 1 | ||
| Xenophilus arseniciresistens | 1 | ||
| Xenophilus azovorans | 1 | ||
| Xenorhabdus | |||
| Xenorhabdus beddingii (Xenorhabdus nematophila subsp. beddingii) | 1 | n | |
| Xenorhabdus bovienii (Xenorhabdus nematophila subsp. bovienii) | 1 | n | |
| Xenorhabdus budapestensis | 1 | n | |
| Xenorhabdus cabanillasii | 1 | n | |
| Xenorhabdus doucetiae | 1 | n | |
| Xenorhabdus eapokensis | 1 | n | neu |
| Xenorhabdus ehlersii | 1 | n | |
| Xenorhabdus griffiniae | 1 | n | |
| Xenorhabdus hominickii | 1 | n | |
| Xenorhabdus indica | 1 | n | |
| Xenorhabdus innexi | 1 | n | |
| Xenorhabdus ishibashii | 1 | n | |
| Xenorhabdus japonica | 1 | n | |
| Xenorhabdus khoisanae | 1 | n | |
| Xenorhabdus koppenhoeferi | 1 | n | |
| Xenorhabdus kozodoii | 1 | n | |
| Xenorhabdus luminescens → Photorhabdus luminescens subsp. luminescens | |||
| Xenorhabdus magdalenensis | 1 | n | |
| Xenorhabdus mauleonii | 1 | n | |
| Xenorhabdus miraniensis | 1 | n | |
| Xenorhabdus nematophila (Xenorhabdus nematophila subsp. nematophila) | 1 | n | |
| Xenorhabdus nematophila subsp. beddingii → Xenorhabdus beddingii | |||
| Xenorhabdus nematophila subsp. bovienii → Xenorhabdus bovienii | |||
| Xenorhabdus nematophila subsp. nematophila → Xenorhabdus nematophila | |||
| Xenorhabdus nematophila subsp. poinarii → Xenorhabdus poinarii | |||
| Xenorhabdus poinarii (Xenorhabdus nematophila subsp. poinarii) | 1 | ||
| Xenorhabdus romanii | 1 | n | |
| Xenorhabdus stockiae | 1 | n | |
| Xenorhabdus szentirmaii | 1 | n | |
| Xenorhabdus thuongxuanensis | 1 | n | neu |
| Xenorhabdus vietnamensis | 1 | n | |
| Xiangella | |||
| Xiangella phaseoli | 1 | ||
| Xuhuaishuia | |||
| Xuhuaishuia manganoxidans – synonym: Brevirhabdus pacifica | neu, Umb. | ||
| Xylanibacter → Prevotella | |||
| Xylanibacter oryzae → Prevotella oryzae | |||
| Xylanibacterium | |||
| Xylanibacterium ulmi | 1 | ||
| Xylanimicrobium | |||
| Xylanimicrobium pachnodae (Promicromonospora pachnodae) | 1 | ||
| Xylanimonas | |||
| Xylanimonas cellulosilytica | 1 | ||
| Xylella | |||
| Xylella fastidiosa → Xylella fastidiosa subsp. fastidiosa | |||
| Xylella fastidiosa subsp. fastidiosa (Xylella fastidiosa) | 1 | p2 | |
| Xylella fastidiosa subsp. multiplex | 1 | p2 | |
| Xylella fastidiosa subsp. pauca | 1 | p2 | |
| Xylella taiwanensis | 1 | p2 | neu |
| Xylophilus | |||
| Xylophilus ampelinus (Xanthomonas ampelina) | 1 | p2 |