Elizabethkingia meningoseptica

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Elizabethkingia meningoseptica
Wet raised colonies with clear margin and characteristic smell after culturing on blood agar, bacteria plated in this way may not show yellow color. Vancomycin sensitivity (clearing around disk) and colistin resistance may lead to mistaking this organism as Gram-positive.
Scientific classification Edit this classification
Domain: Bacteria
Phylum: Bacteroidota
Class: Flavobacteriia
Order: Flavobacteriales
Family: Weeksellaceae
Genus: Elizabethkingia
Species:
E. meningoseptica
Binomial name
Elizabethkingia meningoseptica
(King, 1959) Kim et al., 2005
Synonyms
  • Flavobacterium meningosepticum King 1959
  • Chryseobacterium meningosepticum (King 1959) Vandamme et al. 1994
  • Elizabethkingia meningoseptica (King 1959) Kim et al. 2005

Elizabethkingia meningoseptica is a

frogs; it may be isolated from chronic infectious states, as in the sputum of cystic fibrosis patients. In 1959, American bacteriologist Elizabeth O. King (who isolated Kingella kingae in 1960) was studying unclassified bacteria associated with pediatric meningitis at the Centers for Disease Control and Prevention in Atlanta, when she isolated an organism (CDC group IIa) that she named Flavobacterium meningosepticum (Flavobacterium means "the yellow bacillus" in Latin; meningosepticum likewise means "associated with meningitis and sepsis").[1] In 1994, it was reclassified in the genus Chryseobacterium and renamed Chryseobacterium meningosepticum[2](chryseos = "golden" in Greek, so Chryseobacterium means a golden/yellow rod similar to Flavobacterium). In 2005, a 16S rRNA phylogenetic tree of Chryseobacteria showed that C. meningosepticum along with C. miricola (which was reported to have been isolated from Russian space station Mir in 2001 and placed in the genus Chryseobacterium in 2003[3]) were close to each other but outside the tree of the rest of the Chryseobacteria and were then placed in a new genus Elizabethkingia named after the original discoverer of F. meningosepticum.[4]

Presence in plants

Two species of Elizabethkingia have recently been found to be abundant on the leaf and root surfaces of the tropical tree Gnetum gnemon in Malaysia.[5] Their role in the biology of the plant is unknown. Several other species of tropical trees studied did not have Elizabethkingia present on their leaves or roots, suggesting a host-specific relationship with Gnetum.[citation needed]

Microbiology

Under a microscope, E. meningoseptica appears as slender, slightly curved

urease test. In general, it is negative by the nitrate reductase test, although some strains are positive.[6]

E. meningoseptica grows well on

blood agar and chocolate agar. Colonies are very pale yellow and may not be easily evident at 24 hours. Strains growing better at 40 °C are mostly associated with invasive meningitis.[7] Often, a greyish discoloration is seen around the colonies on blood agar due to proteases and gelatinase. E. meningoseptica grows poorly on MacConkey agar and is considered a glucose oxidizer.[8] Most strains do not grow on colistin nalidixic acid agar because, although they are resistant to colistin, they are susceptible to quinolones such as nalidixic acid.[citation needed
]

E. meningoseptica may show colistin-resistant and

Burkholderia cepacia, which is also a nonfermenter and does not grow well on MacConkey agar. These two can be distinguished by the indole test or the Pyr test, both of which should be clearly negative for B. cepacia and positive for E. meningoseptica. Automated bacterial identification system results should be observed with caution, especially when a patient with Gram-negative bacteremia does not improve with broad-spectrum antibiotic therapy, because several bacteria, including Aeromonas salmonicida (mistaken by ID32 GN[6]) and Sphingobacterium spp. (mistaken by Vitek 2[9]), may be confused with this bacterium, especially the atypical ones. However, unlike many other Aeromonas species such as A. hydrophila and A. punctata, A. salmonicida is indole negative, which can help in distinguishing it in doubtful cases. An automated but so far relatively reliable Rapid NF plus system and API Zym systems use an array of biochemical tests for better identification of nonfermenters and other bacteria and can specifically identify E. meningoseptica.[citation needed
]

Infection

E. meningoseptica predominantly causes outbreaks of meningitis in premature newborns and infants in neonatal intensive care units of underdeveloped countries.[citation needed]

Some of the outbreaks have been linked to sources such as contaminated lipid stock bottles, contaminated venous catheter lines and nutritional solution, and tap water. The bacterium is also a rare cause of

immunocompetent[9] and in a case of a fatal necrotizing fasciitis in a diabetic patient.[10]

Some 48 cases of Elizabethkingia infection resulting in 17 fatalities were reported in Wisconsin over a 5-month period beginning in November 2015.[11]

Antimicrobial susceptibility

This bacterium is usually

rifampin, and novobiocin are considered good alternatives. Most of these are classic drugs for Gram-positive bacteria and not routinely tested on Gram-negative bacteria.[12]

Predictors of poor outcome

Hypoalbuminemia, increased pulse rate at the onset of infection, and central venous line infection were associated with a poor outcome.[13]

Resource persons

At the 2006 meeting of the International Committee on Systematics of Prokaryotes, the organization's subcommittee on the taxonomy of Flavobacterium and Cytophaga-like bacteria named J.-F. Bernardet and B. Bruun as two key authorities on this bacterium.[14]

Unambiguous synonyms

  • Flavobacterium meningosepticum King, 1959 (Approved Lists, 1980)
  • Chryseobacterium meningosepticum (King, 1959) Vandamme et al., 1994
  • Elizabethkingia meningoseptica (King, 1959) Kim et al., 2005

See also

References

  1. PMID 13637033
    .
  2. doi:10.1099/00207713-44-4-827
    .
  3. PMID 14666980
    .
  4. PMID 15879269
    .
  5. S2CID 16040513
    .
  6. ^
    PMID 10998378
    .
  7. ISBN 978-0-387-25497-5
    .
  8. ^ Koneman's Color Atlas and Textbook of Diagnostic Microbiology
  9. ^
    PMID 17644722
    .
  10. PMID 16517926
    .
  11. ^ Meyers, Scottie Lee (March 9, 2016). "A Crash Course In Elizabethkingia, The Rare Bacterial Infection Spreading Across Wisconsin". Wisconsin Public Radio. Archived from the original on April 14, 2023. Retrieved April 10, 2023.
  12. PMID 15243115
    .
  13. ^ Po-Pin Hung; Yu-Hui Lin; Chin-Fu Lin; Meei-Fang Liu; Zhi-Yuan Shi (2008). "Chryseobacterium meningosepticum infection: antibiotic susceptibility and risk factors for mortality" (PDF). Journal of Microbiology, Immunology and Infection. 41: 137–144. Archived from the original (PDF) on 2008-12-01. Retrieved 2010-02-26.
  14. doi:10.1099/ijs.0.64834-0.[permanent dead link
    ]

External links
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