Faecalibacterium
prausnitzii

Ferrimonas
balearica - marina

Ferroglobus
placidus

Ferroplasma
acidiphilum - cupricumulans

Fervidobacterium
gondwanense - islandicum - nodosum - pennivorans - sp.

Filibacter
limicola

Filifactor
villosus

Filobacillus
milosensis

Filomicrobium
fusiforme

Finegoldia
magna

Flammeovirga
aprica

Flavobacterium
aquatile - degerlachei - flevense - frigidimaris - frigoris - fryxellicola - gelidilacus - hibernum - hydatis - indicum - johnsoniae - limicola - pectinovorum - psychrolimnae - psychrophilum - resinovorum - saccharophilum - sp. - succinicans - xanthum

Flectobacillus
major

Flexibacter
aurantiacus - canadensis - elegans - flexilis - litoralis - polymorphus - roseolus - ruber - sp. - tractuosus

Flexistipes
sinusarabici

Flexithrix
dorotheae

Fluoribacter
bozemanae - dumoffii - gormanii

Fluviicola
taffensis

Formivibrio
citricus

Francisella
philomiragia

Frankia
sp.

Frateuria
aurantia

Friedmanniella
antarctica - capsulata - lacustris

Frigoribacterium
faeni

Fulvimarina
pelagi

Fulvimonas
soli

Fusibacter
paucivorans

Fusobacterium
canifelinum - equinum - naviforme - necrophorum - nucleatum