肠球菌

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肠球菌
感染肺部組織的Enterococcus sp.
感染肺部組織的Enterococcus sp.
科學分類
界: Bacteria
門: Firmicutes
綱: Bacilli
目: Lactobacillales
科: Enterococcaceae
屬: 肠球菌屬 Enterococcus
(ex Thiercelin & Jouhaud 1903)
Schleifer & Kilpper-Bälz 1984
Species

E. malodoratus
E. avium
E. durans
E. faecalis
E. faecium
E. gallinarum
E. hirae
E. solitarius
etc.

肠球菌屬学名Enterococcus),是厚壁菌門乳酸菌革蘭氏陽性球菌。经常以成对(双球菌)或短链方式存在。从形态上与鏈球菌屬很难区分[1]。在人类肠道里有两种常见偏利共生肠球菌:粪肠球菌英语Enterococcus faecalis(90-95%)和屎肠球菌英语Enterococcus faecium(5-10%)。其他人體中較稀有的菌群還有E. casseliflavusE. gallinarum,和E. raffinosus.[1]

Physiology and classification[编辑]

Enterococci are facultative anaerobic organisms, i.e., they are capable of cellular respiration in both oxygen-rich and oxygen-poor environments.[2] Though they are not capable of forming spores, enterococci are tolerant of a wide range of environmental conditions: extreme temperature (10-45°C), pH (4.5-10.0) and high sodium chloride concentrations.[3]

Enterococci typically exhibit gamma-hemolysis on sheep's blood agar.[4]

History[编辑]

Members of the genus Enterococcus (from Greek έντερο, éntero, "intestine" and κοκκος, coccos, "granule") were classified as Group D Streptococcus until 1984, when genomic DNA analysis indicated a separate genus classification would be appropriate :D.[5]

Pathology[编辑]

Important clinical infections caused by Enterococcus include urinary tract infections, bacteremia, bacterial endocarditis, diverticulitis, and meningitis.[3][4] Sensitive strains of these bacteria can be treated with ampicillin, penicillin and vancomycin.[6] Urinary tract infections can be treated specifically with nitrofurantoin, even in cases of vancomycin resistance.[7]

From a medical standpoint, an important feature of this genus is the high level of intrinsic antibiotic resistance. Some enterococci are intrinsically resistant to β-lactam-based antibiotics (penicillins, cephalosporins, carbapenems), as well as many aminoglycosides.[4] In the last two decades, particularly virulent strains of Enterococcus that are resistant to vancomycin (vancomycin-resistant Enterococcus, or VRE) have emerged in nosocomial infections of hospitalized patients, especially in the US.[3] Other developed countries, such as the UK, have been spared this epidemic, and, in 2005, Singapore managed to halt an epidemic of VRE.[來源請求] VRE may be treated with quinupristin/dalfopristin (Synercid) with response rates of approximately 70%.[8] Tigecycline has also been shown to have anti-enterococcal activity as has rifampicin.[1]

Enterococcal meningitis is a rare complication of neurosurgery. It often requires treatment with intravenous or intrathecal vancomycin, yet it is debatable as to whether its use has any impact on outcome: the removal of any neurological devices is a crucial part of the management of these infections.[9] New epidemiological evidence has shown that enterococci are major infectious agent in chronic bacterial prostatitis[來源請求]. Enterococci are able to form biofilm in the prostate gland making their eradication difficult.

Enterococcus
分類系統及外部資源
ICD-9 041.04

水質[编辑]

In bodies of water, the acceptable level of contamination is very low; for example in the state of Hawaii, and most of the United States, the limit for water off its beaches is a five-week geometric mean of 35 colony-forming units per 100 ml of water, above which the state may post warnings to stay out of the ocean.[10] In 2004, Enterococcus spp. took the place of fecal coliform as the new USA federal standard for water quality at public salt water beaches and E. coli at fresh water beaches.[11] It is believed to provide a higher correlation than fecal coliform with many of the human pathogens often found in city sewage.[12]

參考完線[编辑]

  1. ^ 1.0 1.1 Gilmore MS, et al. (编). The Enterococci: Pathogenesis, Molecular Biology, and Antibiotic Resistance. Washington, D.C.: ASM Press. 2002. ISBN 978-1-55581-234-8. 
  2. ^ Fischetti VA, Novick RP, Ferretti JJ, Portnoy DA, Rood JI (编). Gram-Positive Pathogens. ASM Press. 2000. ISBN 1-55581-166-3. 
  3. ^ 3.0 3.1 3.2 Fisher K, Phillips C. The ecology, epidemiology and virulence of Enterococcus. Microbiology. June 2009, 155 (Pt 6): 1749–57. doi:10.1099/mic.0.026385-0. PMID 19383684. 
  4. ^ 4.0 4.1 4.2 Ryan KJ, Ray CG (编). Sherris Medical Microbiology 4th. McGraw Hill. 2004: 294–5. ISBN 0-8385-8529-9. 
  5. ^ Schleifer KH; Kilpper-Balz R. Transfer of Streptococcus faecalis and Streptococcus faecium to the genus Enterococcus nom. rev. as Enterococcus faecalis comb. nov. and Enterococcus faecium comb. nov.. Int. J. Sys. Bacteriol. 1984, 34: 31–34. doi:10.1099/00207713-34-1-31. 
  6. ^ Pelletier LL Jr. Microbiology of the Circulatory System. in: Baron's Medical Microbiology (Baron S et al., eds.) 4th. Univ of Texas Medical Branch. 1996. ISBN 0-9631172-1-1. 
  7. ^ Zhanel GG, Hoban DJ, Karlowsky JA. Nitrofurantoin is active against vancomycin-resistant enterococci. Antimicrob. Agents Chemother. January 2001, 45 (1): 324–6. doi:10.1128/AAC.45.1.324-326.2001. PMC 90284. PMID 11120989. 
  8. ^ Tünger A, Aydemir S, Uluer S, Cilli F. In vitro activity of linezolid & quinupristin/dalfopristin against Gram-positive cocci. Indian J Med Res. 2004, 120 (6): 546–52. PMID 15654141. 
  9. ^ Guardado R, Asensi V, Torres JM et al. Post-surgical enterococcal meningitis: clinical and epidemiological study of 20 cases. Scand. J. Infect. Dis. 2006, 38 (8): 584–8. doi:10.1080/00365540600606416. PMID 16857599. 
  10. ^ Clean Water Branch. Hawaii State Department of Health. [2012-05-18]. 
  11. ^ Water Quality Standards for Coastal and Great Lakes Recreation Waters. EPA. [7/9/2004]. 
  12. ^ Jin G, Jeng HW, Bradford H, Englande AJ. Comparison of E. coli, enterococci, and fecal coliform as indicators for brackish water quality assessment. Water Environ. Res. 2004, 76 (3): 245–55. doi:10.2175/106143004X141807. PMID 15338696. 

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