| Spezies | Risiko- gruppe | Bemer- kungen | Status |
| Zavarzinella | |||
| Zavarzinella formosa | 1 | ||
| Zavarzinia | |||
| Zavarzinia compransoris | 1 | ||
| Zeaxanthinibacter | |||
| Zeaxanthinibacter aestuarii | 1 | neu | |
| Zeaxanthinibacter enoshimensis | 1 | ||
| Zhangella → Maritalea | |||
| Zhangella mobilis → Maritalea porphyrae | |||
| Zhihengliuella | |||
| Zhihengliuella aestuarii → Neomicrococcus aestuarii | Umb. | ||
| Zhihengliuella alba | 1 | ||
| Zhihengliuella flava | 1 | ||
| Zhihengliuella halotolerans | 1 | ||
| Zhihengliuella salsuginis | 1 | ||
| Zhihengliuella somnathii | 1 | neu | |
| Zhizhongheella | |||
| Zhizhongheella caldifontis | 1 | neu | |
| Zhongshania | |||
| Zhongshania aliphaticivorans | 1 | neu | |
| Zhongshania antarctica | 1 | ||
| Zhongshania borealis (Spongiibacter borealis) | 1 | Umb. | |
| Zhongshania guokunii | 1 | ||
| Zhouia | |||
| Zhouia amylolytica | 1 | ||
| Zimmermannella = Pseudoclavibacter | |||
| "Zimmermannella alba" | 1 | + | |
| "Zimmermannella bifida" | 1 | + | |
| "Zimmermannella faecalis" | 1 | ||
| Zimmermannella helvola = Pseudoclavibacter helvolus | 1 | ||
| Zobellella | |||
| Zobellella aerophila | 1 | ||
| Zobellella denitrificans | 1 | ||
| Zobellella taiwanensis | 1 | ||
| Zobellia | |||
| Zobellia amurskyensis | 1 | ||
| Zobellia galactanivorans | 1 | ||
| Zobellia laminariae | 1 | ||
| Zobellia russellii | 1 | ||
| Zobellia uliginosa (Flavobacterium uliginosum, Cytophaga uliginosa, Cellulophaga uliginosa) | 1 | ||
| Zoogloea | |||
| Zoogloea caeni | 1 | ||
| Zoogloea oleivorans | 1 | neu | |
| Zoogloea oryzae | 1 | ||
| Zoogloea ramigera | 1 | ||
| Zoogloea resiniphila | 1 | ||
| Zooshikella | |||
| Zooshikella ganghwensis | 1 | ||
| Zooshikella marina | 1 | neu | |
| Zunongwangia | |||
| Zunongwangia atlantica | 1 | ||
| Zunongwangia endophytica | 1 | neu | |
| Zunongwangia mangrovi | 1 | ||
| Zunongwangia profunda (Wangia profunda) | 1 | ||
| Zymobacter | |||
| Zymobacter palmae | 1 | ||
| Zymomonas | |||
| Zymomonas mobilis subsp. francensis | 1 | ||
| Zymomonas mobilis subsp. mobilis | 1 | ||
| Zymomonas mobilis subsp. pomacea | 1 | ||
| Zymophilus | |||
| Zymophilus paucivorans → Propionispira paucivorans | Umb. | ||
| Zymophilus raffinosivorans → Propionispira raffinosivorans | Umb. |