Phylum Proteobacteria, Class Gammaproteobacteria, Order Enterobacteriales, Family Enterobacteriaceae, Genus
Obesumbacterium, Obesumbacterium proteus - type species of the genus, Shimwell 1963. Old synonym: Flavobacterium proteum
Shimwell and Grimes 1936.
Based on PCR tests O. proteus can be subdivided into two biogroups, biogroup 1, which has considerable biochemical and genetic
homology to Hafnia alvei (now considered H. alvei metabolically inactive), and biogroup 2, which is relatively heterogeneous.
Obesumbacterium proteus biogroup 1 may be a synonym of Hafnia alvei hybridization group 1.
Obesumbacterium proteus biogroup 2 is a synonym of Shimwellia pseudoproteus Priest and Barker 2010.
Gram-negative, short, pleomorphic large rods.
Colonies are smooth, 2-5 mm diameter. Facultatively anaerobic, growth temperature
30 - 37 ºC, cannot survive below pH 3.9. Media: Nutrient agar or nutrient broth;
Trypticase Soy Agar ± 5% sheep blood.
Isolated from brewery fermentors, rarely isolated from nature (water, soil and plants).
Is a common contaminant of brewing yeasts causing wort spoilage & undesirable odour due to dimethyl sulfide production. Unknown
- J. G. Holt et al., 1994. Facultatively Anaerobic Gram-Negative Rods. Subgroup 1. Family Enterobacteriaceae. In: Begey’s Manual of
Determinative Bacteriology, 9th-edition, Williams & Wilkins, pp 175-189.
- Andrew G. Prest, John R. M. Hammond, and Gordon S. A. B. Stewart: Biochemical and Molecular Characterization of
Obesumbacterium proteus, a Common Contaminant of Brewing Yeasts, Appl Environ Microbiol. 1994 May; 60(5): 1635–1640.
- Fergus G. Priest andMargaret Barker. Gram-negative bacteria associated with brewery yeasts: reclassification of
Obesumbacterium proteus biogroup 2 as Shimwellia pseudoproteus gen. nov., sp. nov., and transfer of Escherichia blattae to
Shimwellia blattae comb. nov. Int J Syst Evol Microbiol April 2010 60:828-833.
- Don J. Brenner and J.J. Farmer III, 2001. Family I. Enterobacteriaceae. In: Bergey’s Manual of Systematic Bacteriology, Second
edition, Vol two, part B, George M. Garrity (Editor-in-Chief), pp 587-897.
- Geert Huys, Margo Cnockaert, Sharon L. Abbott, J. Michael Janda, and Peter Vandamme. Hafnia paralvei sp. nov., formerly known
as Hafnia alvei hybridization group 2. Int J Syst Evol Microbiol August 2010 60:1725-1728.
For biogroup 1 see Hafnia alvei description. For biogroup 2 see Shimwellia
(c) Costin Stoica