Bacillus
acidicola - aeolius - agaradhaerens - alcalophilus - aminovorans - amyloliquefaciens - aquimaris - arenosi - arseniciselenatis - arsenicus - arvi - atrophaeus - axarquiensis - azotoformans - badius - barbaricus - bataviensis - benzoevorans - carboniphilus - cellulosilyticus - cereus - cibi - circulans - clarkii - clausii - coagulans - cohnii - decolorationis - drentensis - endophyticus - farraginis - fastidiosus - firmus - flexus - fordii - fortis - fumarioli - funiculus - fusiformis - galactosidilyticus - gelatini - gibsonii - halmapalus - halodurans - halophilus - hemicellulosilyticus - herbersteinensis - horikoshii - horti - humi - hwajinpoensis - indicus - infernus - insolitus - jeotgali - koreensis - krulwichiae - lentus - licheniformis - litoralis - luciferensis - macauensis - macyae - mannanilyticus - marisflavi - megaterium - mojavensis - muralis - mycoides - nealsonii - neidei - niacini - novalis - odysseyi - okuhidensis - oleronius - patagoniensis - pseudalcaliphilus - pseudofirmus - pseudomycoides - psychrodurans - psychrosaccharolyticus - psychrotolerans - pumilus - pycnus - ruris - salarius - saliphilus - schlegelii - selenitireducens - seohaeanensis - shackletonii - silvestris - simplex - siralis - smithii - soli - sonorensis - sp. - sphaericus - sporothermodurans - subterraneus - subtilis - taeanensis - thermantarcticus - thermoamylovorans - thermocloacae - thermoterrestis - thuringiensis - tusciae - vallismortis - vedderi - vietnamensis - vireti - wakoensis - weihenstephanensis

Bacteriovorax
litoralis - marinus - stolpii

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

Balnearium
lithotrophicum

Balneatrix
alpica

Barnesiella
viscericola

Bartonella
schoenbuchensis

Bdellovibrio
bacteriovorus

Beggiatoa
alba

Beijerinckia
derxii - indica - mobilis - sp.

Belliella
baltica

Belnapia
moabensis

Bergeriella
denitrificans

Beutenbergia
cavernae

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

Bilophila
wadsworthia

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 - spielmanii - turcica

Bosea
minatitlanensis - thiooxidans

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

Brachymonas
denitrificans

Brachyspira
murdochii

Brackiella
oedipodis

Bradyrhizobium
canariense - elkanii - japonicum - sp.

Brenneria
alni - nigrifluens - quercina - rubrifaciens - salicis

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

Brevibacterium
avium - casei - celere - epidermidis - frigoritolerans - halotolerans - iodinum - linens - luteolum - mcbrellneri - otitidis - paucivorans - picturae - sanguinis - sp. - stationis

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

Brochothrix
campestris - thermosphacta

Bryantella
formatexigens

Budvicia
aquatica

Bulleidia
extructa

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

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

Butyribacterium
methylotrophicum

Butyrivibrio
crossotus - fibrisolvens - hungatei - sp.

Byssovorax
cruenta