“Enterobacteriaceae”的意思、由来-开放百科全书

This family is the only representative in the order Enterobacteriales of the class Gammaproteobacteria in the phylum Proteobacteria.^[2]^[3]^[4]^[5]

Enterobacteriaceae includes, along with many harmless symbionts, many of the more familiar pathogens, such as Salmonella, Escherichia coli, Yersinia pestis, Klebsiella, and Shigella. Other disease-causing bacteria in this family include Proteus, Enterobacter, Serratia, and Citrobacter. Phylogenetically, in the Enterobacteriales, several peptidoglycan-less insect endosymbionts{{citation needed|date=November 2013}} form a sister clade to the Enterobacteriaceae, but as they are not validly described, this group is not officially a taxon; examples of these species are Sodalis, Buchnera, Wigglesworthia, Baumannia cicadellinicola, and Blochmannia, but not former Rickettsias.^[6] Members of the Enterobacteriaceae can be trivially referred to as enterobacteria or "enteric bacteria",^[7] as several members live in the intestines of animals. In fact, the etymology of the family is enterobacterium with the suffix to designate a family (aceae)—not after the genus Enterobacter (which would be "Enterobacteraceae")—and the type genus is Escherichia.

Morphology

Members of the Enterobacteriaceae are bacilli (rod-shaped), and are typically 1–5 μm in length. They typically appear as medium to large-sized grey colonies on blood agar, although some can express pigments (such as Serratia marcescens).

Most have many flagella used to move about, but a few genera are nonmotile. Most members of Enterobacteriaceae have peritrichous, type I fimbriae involved in the adhesion of the bacterial cells to their hosts.

Metabolism

Like other proteobacteria, enterobactericeae have Gram-negative stains,^[8] and they are facultative anaerobes, fermenting sugars to produce lactic acid and various other end products. Most also reduce nitrate to nitrite, although exceptions exist (e.g. Photorhabdus). Unlike most similar bacteria, enterobacteriaceae generally lack cytochrome C oxidase, although there are exceptions (e.g. Plesiomonas shigelloides).

Ecology

Many members of this family are normal members of the gut microbiota in humans and other animals, while others are found in water or soil, or are parasites on a variety of different animals and plants.

Model organisms and medical relevance

Escherichia coli is one of the most important model organisms, and its genetics and biochemistry have been closely studied.

Some enterobacteria are important pathogens, e.g. Salmonella, Shigella, or Yersinia, e.g. because they produce endotoxins. Endotoxins reside in the cell wall and are released when the cell dies and the cell wall disintegrates. Some members of the Enterobacteriaceae produce endotoxins that, when released into the bloodstream following cell lysis, cause a systemic inflammatory and vasodilatory response. The most severe form of this is known as endotoxic shock, which can be rapidly fatal.

Genera

Accepted

Candidatus

Provisional

Identification

To identify different genera of Enterobacteriaceae, a microbiologist may run a series of tests in the lab. These include:^[9]

In a clinical setting, three species make up 80 to 95% of all isolates identified. These are Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis.

Antibiotic resistance

Several Enterobacteriaceae strains have been isolated which are resistant to antibiotics including carbapenems, which are often claimed as "the last line of antibiotic defense" against resistant organisms. For instance, some Klebsiella pneumoniae strains are carbapenem resistant.^[10]

References

1. ^{{cite web|url=http://www.bacterio.net/-classifgenerafamilies.html#Enterobacteriaceae |accessdate=26 June 2016 |title=List of genera included in families - Enterobacteriaceae |publisher=List of Prokaryotic Names with Standing in Nomenclature}}
2. ^{{cite book |series=Bergey's Manual of Systematic Bacteriology|volume=2B|title=The Gammaproteobacteria|editor=George M. Garrity |author=Don J. Brenner |author2=Noel R. Krieg |author3=James T. Staley |publisher=Springer|location= New York |edition=2nd|isbn=978-0-387-24144-9 |pages=1108 |url=https://www.springer.com/life+sciences/book/978-0-387-24144-9 |date=July 26, 2005| origyear =1984 (Williams & Wilkins)|id=British Library no. GBA561951}}
3. ^Zipcodezoo site Enterobacteriales {{webarchive|url=https://web.archive.org/web/20140427071000/http://zipcodezoo.com/Key/Bacteria/Enterobacteriales_Order.asp |date=2014-04-27 }} accessed 9 Mar 2013
4. ^NCBI [https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Undef&id=91347 Enterobacteriales ] accessed 9 Mar 2013
5. ^Taxonomicon Enterobacteriales accessed 9 Mar 2013
6. ^{{Cite journal | last1 = Williams | first1 = K. P. | last2 = Gillespie | first2 = J. J. | last3 = Sobral | first3 = B. W. S. | last4 = Nordberg | first4 = E. K. | last5 = Snyder | first5 = E. E. | last6 = Shallom | first6 = J. M. | last7 = Dickerman | first7 = A. W. | title = Phylogeny of Gammaproteobacteria | journal = Journal of Bacteriology | volume = 192 | issue = 9 | pages = 2305–2314 | year = 2010 | pmid = 20207755 | pmc = 2863478 | doi = 10.1128/JB.01480-09}}
7. ^{{Cite web |url=http://inst.bact.wisc.edu/inst/index.php?module=book&type=user&func=displayarticle&art_id=268] |title=Archived copy |access-date=2019-01-26 |archive-url=https://web.archive.org/web/20111210215051/http://inst.bact.wisc.edu/inst/index.php?module=Book |archive-date=2011-12-10 |dead-url=yes |df= }}
8. ^{{cite web |url=http://www.mercksource.com/pp/us/cns/cns_hl_dorlands_split.jsp?pg=/ppdocs/us/common/dorlands/dorland/three/000035660.htm |title=Dorlands Medical Dictionary:Enterobacteriaceae |work= |accessdate=}}
9. ^MacFaddin, Jean F. Biochemical Tests for Identification of Medical Bacteria. Williams & Wilkins, 1980, p 441.
10. ^[https://www.cdc.gov/HAI/organisms/klebsiella/klebsiella.html Centers for Disease Control and Prevention - Klebsiella] Quotation: "Increasingly, Klebsiella bacteria have developed antimicrobial resistance, most recently to the class of antibiotics known as carbapenems."