alkalihalobacillus clausii alkalihalobacillus clausii alkalihalobacillus clausii or its old scientific name bacillus clausii is a rod-shaped, motile, and spore-forming bacterium that lives in the soil but is also a natural microflora of the mammalian gastrointestinal tract. it is classified as probiotic microorganism that maintains a symbiotic relationship with the host organism. it is currently being studied in relation to respiratory infections and some gastrointestinal disorders. bacillus clausii has been found to produce antimicrobial substances that are active against gram-positive bacteria including staphylococcus aureus, enterococcus faecium and clostridium difficile. it is sold as an anti-diarrhoea and under the brand name erceflora by sanofi. alkalihalobacillus clausii a. clausii from enterogermina on a glass slide scientific classification domain: bacteria phylum: bacillota class: bacilli order: bacillales family: bacillaceae genus: alkalihalobacillus species: a. clausii binomial name alkalihalobacillus clausiinielsen et al. 1995 this species has been recently transferred into the genus alkalihalobacillus. the correct nomenclature is thus alkalihalobacillus clausii. genome structure alkalihalobacillus clausii has a relatively small genome that contains 4.30 mbp with 4,108 protein coding genes.