Legionella nagasakiensis
A Microbial Biorealm page on the genus Legionella nagasakiensis
Classification
Higher order taxa
Domain (Bacteria); Phylum (Proteobacteria); Class (Gammaproteobacteria); Order (Legionellales); Family (Legionellaceae); Genus (Legionella)
Species
Species (nagasakiensis)
Legionella nagasakiensis
Description and significance
L. nagasakiensis is very similar to other species of Legionella, but differs due to a variety of novel proteins and other molecules not seen in the other 52 species. It is a gram negative bacillus although depending on conditions it can appear to be slightly coccoid as well. Also, like the other species of Legionella, it causes Legionnaires disease. There are several strains of nagasakiensis found through the world, two strains were found in Australian drinking water, one in a U.S Legionnaires patient, and the initial strain was found at the Nagasaki Municipal Medical Center, Japan thus its name [1].
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] Yang Genyan, Robert F. Benson, Rodney M. Ratcliff, Ellen W. Brown, Arnold G. Steigerwalt, W. Lanier Thacker, Maryam I. Daneshvar, Roger E. Morey, Atsushi Saito and Barry S. Fields (2012). Legionella nagasakiensis sp. nov., isolated from water samples and from a patient with pneumonia. International Journal of Systematic and Evolutionary Microbiology 62, 284–288. DOI 10.1099/ijs.0.027193-0
[1] Furuhata Katsunori, Akiko Edagawa, Hiroshi Miyamoto, Keiichi Goto, Shin-Ichi Yoshida, Masafumi Fukuyama (2011). The first case of Legionella nagasakiensis isolation from hot spring water. https://www.jstage.jst.go.jp/article/bio/16/4/16_4_171/_pdf Biocontrol Science Vol. 16, Issue 4, 171-176.
[1] Meghan M. Pearce, Nicole Theodoropoulos, Gary A. Noskin, John P. Flaherty, Mary E. Stemper, Teresa Aspeslet, Nicholas P. Cianciotto, and Kurt D. Reed (2011). Native valve endocarditis due to a novel strain of Legionella. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3165573/ Journal of Clinical Microbiology 49(9): 3340–3342. PMCID: PMC3165573
[1] GenBank: ACI87823.1 macrophage infectivity potentiator protein, partial [Legionella nagasakiensis] http://www.ncbi.nlm.nih.gov/protein/ACI87823.1
