View source for Biology:Legionella clemsonensis

{{Short description|Species of bacterium}}
{{Speciesbox
| image =
| genus = Legionella
| species = clemsonensis
| authority = Palmer et al. 2016
}}

'''''Legionella clemsonensis''''' was isolated in 2006, but was described in 2016 by [[Organization:Clemson University|Clemson University]] researchers.<ref name=":4" /> It is a Gram-negative bacterium.

== Taxonomic and phylogenetic description ==
“''Legionella''” is named after the American Legion convention where the first outbreak occurred, killing 34 people and sickening 221 individuals in 1976.<ref>{{Cite news|url=https://www.nytimes.com/2006/08/01/health/01docs.html|title=In Philadelphia 30 Years Ago, an Eruption of Illness and Fear|last=Altman|first=Lawrence K.|date=2006-08-01|work=The New York Times|access-date=2017-04-23|issn=0362-4331}}</ref> It occurred in Philadelphia during the convention for the association of the U.S. veterans. The specific name ''clemsonensis''” derives from Clemson University, where  undergraduates DNA-sequenced this new strain.<ref>{{Cite news|url=https://phys.org/news/2016-10-clemson-students-legionella-strain-clemsonensis.html|title=Clemson students name novel Legionella strain: Clemsonensis|access-date=2017-04-23}}</ref> ''Legionella'' has a correlation with another genus called ''[[Biology:Coxiella (bacterium)|Coxiella]]''. Both cause lung infection that can eventually lead to pneumonia due to the intracellular bacteria in [[Chemistry:Aerosol|aerosol]]s.<ref>{{Cite journal|last1=Sauer|first1=John Demian|last2=Shannon|first2=Jeffrey G.|last3=Howe|first3=Dale|last4=Hayes|first4=Stanley F.|last5=Swanson|first5=Michele S.|last6=Heinzen|first6=Robert A.|date=2005-08-01|title=Specificity of Legionella pneumophila and Coxiella burnetii vacuoles and versatility of Legionella pneumophila revealed by coinfection|url=https://experts.umich.edu/en/publications/specificity-of-legionella-pneumophila-and-coxiella-burnetii-vacuo|journal=Infection and Immunity|language=en|volume=73|issue=8|pages=4494–504|doi=10.1128/IAI.73.8.4494-4504.2005|issn=0019-9567|pmc=1201193|pmid=16040960}}</ref>

== Discovery ==
Based on physical characteristics, phylogenetic analysis, and membrane fatty-acid composition,  the organism was found to represent a unique lineage within the ''Legionella'' bacteria. The specific strain for ''Legionella clemsonensis'' is D5610.<ref name=":0">{{Cite journal|last1=Palmer|first1=Allison|last2=Painter|first2=Joseph|last3=Hassler|first3=Hayley|last4=Richards|first4=Vincent P.|last5=Bruce|first5=Terri|last6=Morrison|first6=Shatavia|last7=Brown|first7=Ellen|last8=Kozak-Muiznieks|first8=Natalia A.|last9=Lucas|first9=Claressa|date=2016-10-01|title=Legionella clemsonensis sp. nov.: a green fluorescing Legionella strain from a patient with pneumonia|journal=Microbiology and Immunology|language=en|volume=60|issue=10|pages=694–701|doi=10.1111/1348-0421.12439|pmid=27619817|s2cid=3331351|issn=1348-0421|doi-access=free}}</ref> It was named in honor of the research group of students from the Clemson’s Creative Inquiry.<ref name=":4">{{Cite web|url=http://newsstand.clemson.edu/mediarelations/bacteria-strain-named-by-clemson-students/|title=Bacteria strain named by Clemson students|website=Newsstand {{!}} Clemson University News and Stories, South Carolina|access-date=2017-04-24}}</ref> ''Legionella clemsonensis'' was first isolated in 2006 from the bronchial wash of a patient diagnosed with [[Medicine:Pneumonia|pneumonia]].<ref name=":0" /> Bronchial washing is part of a bronchoscopy procedure.<ref name=":0" /> After being isolated and stored, strain D5610 was acquired by the Centers for Disease Control and Prevention (CDC),<ref name=":4" /> which sent 68 strains of ''Legionella'', including strain D5610, for students to analyze at Clemson.<ref name=":4" /> When isolated, it was shown to be very similar to bacterial genus ''[[Biology:Legionella|Legionella]]''. Researchers stated "it was identified as ''Legionella'' based on sequencing, cellular fatty-acid analysis, biochemical reactions, and biofilm characterization."<ref name=":0" /> For a physical characterization of ''L.a clemsonensis'', it was streaked for a single colony isolation using a charcoal yeast extract agar and required cysteine for primary isolation.<ref name=":0" /> No growth was shown, which is typical of ''Legionella'' strains.  A characteristic of ''L. clemsonensis'' is that it has a single, polar flagellum.<ref name=":0" /> Researchers also used fatty-acid methyl-ester analyses to distinguish differences between the ''Legionella'' strains.<ref name=":0" /> Cellular fatty-acid composition was analyzed using a [http://www.midi-inc.com/pages/microbial_id.html Sherlock microbial Identification System].<ref name=":1" />

== Preliminary characterization ==
''Legionella clemsonensis'' was determined as a special lineage within the genus ''Legionella'' based on its phylogenetic analysis and physical appearance. It is a Gram-negative bacterium that is rod-shaped with one polar flagellum to help it move around. The strain can grow between 26 and 45&nbsp;°C, forming biofilms that are similar to  ''L. pneumophila'' Philadelphia 1.<ref name=":0" /> The strain D5610 of ''L. clemsonensis'' shows a distinctive temperature constraint compared to many of the ''Legionella'' species that do not grow under 26&nbsp;°C and a restriction of temperatures above 45&nbsp;°C . Most ''Legionella'' species have the ability to grow as high as 63&nbsp;°C and very slowly at temperatures as low as 5&nbsp;°C.<ref name=":1">{{Cite journal|last=Declerck|first=Priscilla|date=2010-03-01|title=Biofilms: the environmental playground of Legionella pneumophila|journal=Environmental Microbiology|volume=12|issue=3|pages=557–566|doi=10.1111/j.1462-2920.2009.02025.x|issn=1462-2920|pmid=19678829|doi-access=}}</ref> At both 37 and 26&nbsp;°C, strain D5610 was found to grow more slowly than ''L. pneumophila'' Philadelphia 1, and it also formed a significant amount of pigment that was less produced.<ref name=":1" /> These attributes suggest that this isolation is a standard ''Legionella'' species, for which the name ''Legionella clemsonensis'' was used. ''Legionella'' is considered to be pathogenic in humans and is one of the leading outbreaks found in constructed water systems. Because the biofilms are the source, countless outbreaks that originated from water systems and the ability of a species to form biofilms both can contribute to ''L. clemonensis’s'' pathogenicity.<ref name=":2">{{Cite journal|last=Ashbolt|first=Nicholas J.|date=2015-06-19|title=Environmental (Saprozoic) Pathogens of Engineered Water Systems: Understanding Their Ecology for Risk Assessment and Management|journal=Pathogens|language=en|volume=4|issue=2|pages=390–405|doi=10.3390/pathogens4020390|pmc=4493481|pmid=26102291|doi-access=free}}</ref> The process of characterizing and sequencing the strain D5610 is still undergoing  investigation. Because this strain is still being investigated, no specific [[Biology:Metabolism|metabolism]] has been shown for ''L. clemsonensis''. Yet, ''Legionella’s'' usual metabolism is a facultative intracellular pathogen that increases in large numbers inside free-living amoebae, as well as macrophages and other protozoa.<ref name=":3">{{Cite journal|last1=Scheikl|first1=Ute|last2=Tsao|first2=Han-Fei|last3=Horn|first3=Matthias|last4=Indra|first4=Alexander|last5=Walochnik|first5=Julia|date=2016-01-01|title=Free-living amoebae and their associated bacteria in Austrian cooling towers: a 1-year routine screening|journal=Parasitology Research|volume=115|issue=9|pages=3365–3374|doi=10.1007/s00436-016-5097-z|issn=0932-0113|pmc=4980419|pmid=27177720}}</ref>  In water systems, the pathogen lives in low metabolic state in the biofilms. A known strain of Legionella called in vitro ''L. pneumophila'' does not grow on standard media such as blood agar, because of a pH of 6.9 and certain amino acids such as cysteine being required.<ref name=":2" /> Yet when these requirements are met, the growth in the aerobic conditions is still slow. Up to 5 days are needed for colonies to be produced.<ref name=":3" /> The genomics have yet to be stated for this particular strain of ''Legionella'', as well as the habitats.

== Importance ==
''Legionella clemsonensis''  is pathogenic; most ''Legionella'' species are commonly known to cause pneumonia.  A feature that sets ''L. clemsonensis'' apart is that under ultraviolet light, it fluoresces green,<ref name=":0" /> which differs from other ''Legionella'' strains because they usually  fluoresce blue, red, or yellow.<ref name=":0" />

== References ==
{{Reflist}}

{{Taxonbar|from=Q28407522}}

[[Category:Gram-negative bacteria]]
[[Category:Legionellales]]
[[Category:Pneumonia]]

{{Sourceattribution|Legionella clemsonensis}}