Brevibacterium linens

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A Microbial Biorealm page on the genus Brevibacterium linens

Classification

Higher order taxa

Bacteria; Actinobacteria; Actinobacteria; Actinobacteridae; Actinomycetales; Micrococcineae; Brevibacteriaceae; Brevibacterium

Species

Species (linens)

Brevibacterium linens

Description and significance

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Rahnella aquatilis is a relatively rare gram-negative rod-shaped bacteria which has been found in fresh water, soil, certain animals such as snails [5] and certain beetles, [4] and isolated human clinical specimens. [2] This bacterium is of importance because of its abundance and its disease-causing ability in humans. Many different strains have been isolated, and presumably more will be disocvered.

Genome structure

As of the year 2000, at least 70 strains of Rahnella aquatilis have been identified [1]. According to the National Center for Biotechnology Information (NCBI), the whole genome has been sequenced for R. aquatilis Strain Y9602. This particular strain has a genome consisting of 4,864,217 basepairs, with two identified plasmids [2]. Another strain, Rahnella aquatilis CUETM 77-115, was shown to have a genome consisting of 5,440,269 basepairs, and had a G-C content of 52.1% [3].

Cell and colony structure

Rahnella aquatilis is gram-negative rod-shaped bacterium, about 2-3 microns in length. Strain ISL 19 was isolated from soybean rhizosphere, and was seen to have several flagella for motility [6]. The bacterium can be readily cultured in the laboratory.

Metabolism

Rahnella aquatilis is a facultative anaerobe (it can live in the absence or presence of oxygen) that fixes Nitrogen [2]. R. aquatilis metabolizing whey lactose produces high levels of organic acids (except for lactic acid) [7].

Ecology

Rahnella aquatilis is named so because of its prevalence in fresh water. It has been found around the globe in places like the United States, Korea, Japan, Russia, the Ukraine, and Egypt. R. aquatilis has also been found in humans, soil, and snails [5]. One of the most unusual places for the the microbe to have been found was inside the gut of certain speicies of longicorn beetles in Korea [4].

Pathology

Rahnella aquatilis is pathogenic in humans. The organism can be diagnosed in patients via blood cultures, respiratory washings, and in wound cultures. Various infections, such as bacteremia (from renal infection), sepsis, respiratory infection, and urinary tract infection can be the result. One case involved an 11-month-old girl with congenital heart disease who developed infective endocarditis [8]. Another case involved a 76-year-old male who had prostatic hyperplasia presenting with acute pyelonephritis [9]. It is noted that R. aquatilis can potentially cause life-threatening infections in humans, infants and adults alike, especially the immunocompromised and organ transplant recipients. Treatments have included intravenous and oral levofloxacin therapy (and other members of the quinolone family).

References

[1] NCBI. U.S. National Library of Medicine. <http://www.ncbi.nlm.nih.gov/>

[2] Rattray, Fergal P., and Patrick F. Fox. "Aspects of Enzymology and Biochemical Properties of Brevibacterium Linens Relevant to Cheese Ripening." Journal of Dairy Science, Volume 82, 1999, Pages 891-909.

[3] Sorhaug, Terje, and John Ordal. "Cell-Bound Lipase and Esterase of Brevibacterium Linens." Applied Microbiology, Volume 25, 1974, Pages 607-608.

Edited by Brittany Harlow, student of Dr. Lisa R. Moore, University of Southern Maine, Department of Biological Sciences, http://www.usm.maine.edu/bio