Bacillus
acidicola - acidovorans - aeolius - agaradhaerens - alcalophilus - aminovorans - amyloliquefaciens - aquimaris - arenosi - arseniciselenatis - arsenicus - arvi - atrophaeus - axarquiensis - azotoformans - badius - barbaricus - bataviensis - benzoevorans - caldotenax - caldovelox - carboniphilus - cellulosilyticus - cereus - chitinolyticus - cibi - circulans - cirroflagellosus - clarkii - clausii - coagulans - cohnii - decolorationis - drentensis - edaphicus - ehimensis - endophyticus - epiphytus - farraginis - fastidiosus - filicolonicus - firmus - flexus - fordii - fortis - freudenreichii - fumarioli - funiculus - fusiformis - galactosidilyticus - gelatini - gibsonii - glucanolyticus - halmapalus - haloalkaliphilus - halodurans - halophilus - hemicellulosilyticus - herbersteinensis - horikoshii - horti - humi - hwajinpoensis - indicus - infernus - insolitus - jeotgali - koreensis - krulwichiae - laevolacticus - lentus - licheniformis - litoralis - longisporus - lubinskii - luciferensis - macauensis - macroides - macyae - malacitensis - mannanilyticus - marisflavi - marismortui - maroccanus - medusa - megaterium - methanolicus - mojavensis - mucilaginosus - muralis - mycoides - naganoensis - nealsonii - neidei - niacini - nitritollens - novalis - odysseyi - okuhidensis - oleronius - pacificus - patagoniensis - pseudalcaliphilus - pseudoalcaliphilus - pseudofirmus - pseudogordonae - pseudomegaterium - pseudomycoides - psychrodurans - psychrosaccharolyticus - psychrotolerans - pumilus - pycnus - racemilacticus - ruris - salarius - saliphilus - schlegelii - selenitireducens - seohaeanensis - shackletonii - silvestris - simplex - siralis - smithii - soli - sonorensis - sp. - sphaericus - sporothermadurans - sporothermodurans - subterraneus - subtilis - taeanensis - thermantarcticus - thermoamylovorans - thermocloacae - thermocloaceae - thermoterrestis - thuringiensis - tusciae - vallismortis - vedderi - velezensis - vietnamensis - vireti - viscosus - wakoensis - weihenstephanensis

Bacteriovorax
litoralis - marinus - starrii - stolpii

Bacteroides
acidifaciens - barnesiae - caccae - cellulosolvens - coagulans - coprocola - coprosuis - distasonis - dorei - eggerthii - finegoldii - fragilis - galacturonicus - gallinarum - helcogenes - intestinalis - massiliensis - merdae - nordii - ovatus - plebeius - pyogenes - salanitronis - sp. - splanchnicus - stercoris - suis - thetaiotaomicron - uniformis - ureolyticus - vulgatus - xylanolyticus

Balnearium
lithotrophicum

Balneatrix
alpica

Barnesiella
viscericola

Bartonella
alsatica - bacilliformis - birtlesii - bovis - capreoli - clarridgeiae - doshiae - elizabethae - grahamii - henselae - quintana - schoenbuchensis - taylorii - tribocorum - vinsonii

Bdellovibrio
bacteriovorus - sp.

Beggiatoa
alba

Beijerinckia
acida - congensis - derxii - fluminensis - indica - mobilis - sp.

Belliella
baltica

Belnapia
moabensis

Beneckea
hyperoptica

Bergeriella
denitrificans

Bergeyella
zoohelcum

Beutenbergia
cavernae

Bifidobacterium
adolescentis - angulatum - animalis - asteroides - bifidum - boum - breve - catenulatum - choerinum - coryneforme - cuniculi - dentium - gallicum - gallinarum - indicum - infantis - lactis - longum - magnum - merycicum - minimum - pseudocatenulatum - pseudolongum - psychraerophilum - pullorum - ruminantium - saeculare - scardovii - subtile - thermacidophilum - thermophilum

Bilophila
wadsworthia

Bizionia
paragorgiae

Blastobacter
aggregatus - capsulatus - denitrificans

Blastochloris
sulfoviridis - viridis

Blastococcus
aggregatus - saxobsidens - sp.

Blastomonas
natatoria - ursincola

Blastopirellula
marina

Bogoriella
caseilytica

Bordetella
avium - bronchiseptica - hinzii - holmesii - parapertussis - pertussis - petrii - trematum

Borrelia
afzelii - burgdorferi - garinii - hermsii - lusitaniae - spielmanii - turcica - valaisiana

Bosea
eneae - massiliensis - minatitlanensis - thiooxidans - vestrisii

Brachybacterium
alimentarium - conglomeratum - faecium - fresconis - muris - nesterenkovii - paraconglomeratum - rhamnosum - sacelli - tyrofermentans

Brachymonas
denitrificans

Brachyspira
alvinipulli - murdochii

Brackiella
oedipodis

Bradyrhizobium
betae - canariense - elkanii - japonicum - liaoningense - sp. - yuanmingense

Branhamella
catarrhalis - caviae - cuniculi - ovis - sp.

Brenneria
alni - nigrifluens - quercina - rubrifaciens - salicis

Brevibacillus
agri - borstelensis - brevis - centrosporus - choshinensis - formosus - invocatus - laterosporus - levickii - limnophilus - parabrevis - reuszeri - sp. - thermoruber

Brevibacterium
antiquum - aurantiacum - avium - casei - celere - epidermidis - frigoritolerans - genomospecies - halotolerans - iodinum - linens - liquefaciens - luteolum - mcbrellneri - otitidis - paucivorans - permense - picturae - sanguinis - sp. - stationis

Brevundimonas
alba - aurantiaca - bacteroides - diminuta - intermedia - mediterranea - nasdae - sp. - subvibrioides - terrae - variabilis - vesicularis

Brochothrix
campestris - thermosphacta

Brumimicrobium
glaciale

Bryantella
formatexigens

Budvicia
aquatica

Bulleidia
extructa

Burkholderia
ambifaria - ambiferia - andropogonis - anthina - caledonica - caribensis - caryophylli - cenocepacia - cepacia - cocovenenans - dolosa - ferrariae - fungorum - gladioli - glathei - glumae - graminis - hospita - kururiensis - multivorans - phenacinium - phenazinium - phenoliruptrix - phymatum - phytofirmans - plantarii - pyrrocinia - sacchari - sordidicola - sp. - stabilis - terrae - terricola - thailandensis - tropica - tuberum - ubonensis - unamae - vandii - vietnamiensis - xenovorans

Buttiauxella
agrestis - brennerae - ferragutiae - gaviniae - izardii - noackiae - warmboldiae

Butyribacterium
methylotrophicum

Butyrivibrio
crossotus - fibrisolvens - hungatei - sp.

Byssovorax
cruenta