''Elizabethkingia meningoseptica'' is a Gram-negative, rod-shaped bacterium widely distributed in nature (e.g. fresh water, salt water, or soil). It may be normally present in fish and frogs; it may be isolated from chronic infectious states, as in the sputum of cystic fibrosis patients. In 1959, American bacteriologist

Elizabeth O. King Elizabeth Osborne King (October 12, 1912April 8, 1966) was an American microbiologist who discovered and described bacteria of medical importance at the United States Centers for Disease Control and Prevention from the late 1940s through the ear ...

(who isolated ''

Kingella kingae ''Kingella kingae'' is a species of Gram-negative facultative anaerobic β-hemolytic coccobacilli. First isolated in 1960 by Elizabeth O. King, it was not recognized as a significant cause of infection in young children until the 1990s, when ...

'' in 1960) was studying unclassified bacteria associated with pediatric

meningitis Meningitis is acute or chronic inflammation of the protective membranes covering the brain and spinal cord, collectively called the meninges. The most common symptoms are fever, headache, and neck stiffness. Other symptoms include confusion or ...

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

and sepsis"). In 1994, it was reclassified in the genus ''Chryseobacterium'' and renamed ''Chryseobacterium meningosepticum''(''chryseos'' = "golden" in Greek, so ''Chryseobacterium'' means a golden/yellow rod similar to ''Flavobacterium''). In 2005, a

16S rRNA 16S rRNA may refer to: * 16S ribosomal RNA 16 S ribosomal RNA (or 16 S rRNA) is the RNA component of the 30S subunit of a prokaryotic ribosome ( SSU rRNA). It binds to the Shine-Dalgarno sequence and provides most of the SSU structure. The g ...

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) were close to each other but outside the tree of the rest of the Chryseobacteria and were then placed in a new genus ''

Elizabethkingia ''Elizabethkingia'' is a genus of bacterium described in 2005, named after Elizabeth O. King, the discoverer of the type species. Before this genus being formed in 2005, many of the species of ''Elizabethkingia'' were classified in the '' Ch ...

'' named after the original discoverer of ''F. meningosepticum''.

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 ''Gnetum gnemon'' is a species of ''Gnetum'' native to southeast Asia and the western Pacific Ocean islands, from Mizoram and Assam in India, south and east through Indonesia and Malaysia to the Philippines, Fiji, and Hawaii in the United States ...

'' in Malaysia. 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''.

Microbiology

Under a microscope, ''E. meningoseptica'' appears as slender, slightly curved rods which are nonmotile and are negative by Gram stain. They do not form

spore In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, f ...

s, and require oxygen to survive. ''E. meningoseptica'' is positive by the catalase test, the oxidase test, and the indole test. It is negative by the urease test. In general, it is negative by the

nitrate reductase test The nitrate reductase test is a test to differentiate between bacteria based on their ability or inability to reduce nitrate (NO3−) to nitrite (NO2−) using anaerobic respiration. Procedure Various assays for detecting nitrate reduction have be ...

, although some strains are positive. ''E. meningoseptica'' grows well on

blood agar An agar plate is a Petri dish that contains a growth medium solidified with agar, used to Microbiological culture, culture microorganisms. Sometimes selective compounds are added to influence growth, such as antibiotics. Individual microorganism ...

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. 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. 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. ''E. meningoseptica'' may show colistin-resistant and vancomycin-sensitive growth, which is paradoxic for a Gram-negative bacterium, but resembles ''

Burkholderia cepacia ''Burkholderia cepacia'' complex (BCC), or simply ''Burkholderia cepacia'', is a group of catalase-producing, lactose-nonfermenting, Gram-negative bacteria composed of at least 20 different species, including ''B. cepacia'', '' B. mul ...

'', 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 Pyr may refer to: * Pyr (''Encantadia''), a character in the Encantadia franchise *Pyr (publisher) * Pyridine *Pyridoxine, vitamin B6 *Pyrrolidonyl-β-naphthylamide, used in microbiology to distinguish certain Streptococcal organisms *Pyruvic acid ...

, 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) and ''

Sphingobacterium ''Sphingobacterium'' is a genus in the family Sphingobacteriaceae. The genus ''Sphingobacterium'' is characterized by the high concentrations of sphingolipid, sphingophospholipids as lipid components.), 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''.

Infection

''E. meningoseptica'' predominantly causes outbreaks of

in premature newborns and infants in neonatal intensive care units of underdeveloped countries. 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

nosocomial pneumonia Hospital-acquired pneumonia (HAP) or nosocomial pneumonia refers to any pneumonia contracted by a patient in a hospital at least 48–72 hours after being admitted. It is thus distinguished from community-acquired pneumonia. It is usually caused by ...

, endocarditis,

postoperative Surgery ''cheirourgikē'' (composed of χείρ, "hand", and ἔργον, "work"), via la, chirurgiae, meaning "hand work". is a medical specialty that uses operative manual and instrumental techniques on a person to investigate or treat a pat ...

bacteremia Bloodstream infections (BSIs), which include bacteremias when the infections are bacterial and fungemias when the infections are fungal, are infections present in the blood. Blood is normally a sterile environment, so the detection of microb ...

, and meningitis in immunocompromised adults. Only recently has it also been found to cause soft-tissue infection and sepsis in the immunocompetent and in a case of a fatal necrotizing fasciitis in a diabetic patient. Some 48 cases of ''Elizabethkingia'' infection resulting in 17 fatalities were reported in Wisconsin over a 5-month period beginning in November 2015.

Antimicrobial susceptibility

This bacterium is usually multiresistant to antibiotics typically prescribed for treating Gram-negative bacterial infections, including extended-spectrum beta-lactam agents (due to production by most strains of two betalactamases: one ESBL and one class B carbapenem-hydrolyzing metallolactamase), aminoglycosides, tetracycline, and

chloramphenicol Chloramphenicol is an antibiotic useful for the treatment of a number of bacterial infections. This includes use as an eye ointment to treat conjunctivitis. By mouth or by injection into a vein, it is used to treat meningitis, plague, cholera, a ...

. Though vancomycin has been used in the past, its high Minimum inhibitory concentration (16 µg/ml) has led to a search for alternatives, especially for meningitis. Presently, ciprofloxacin, minocycline, trimethoprim-sulfamethoxazole, rifampin, and

novobiocin Novobiocin, also known as albamycin or cathomycin, is an aminocoumarin antibiotic that is produced by the actinomycete '' Streptomyces niveus'', which has recently been identified as a subjective synonym for ''S. spheroides'' a member of the clas ...

are considered good alternatives. Most of these are classic drugs for Gram-positive bacteria and not routinely tested on Gram-negative bacteria.

Predictors of poor outcome

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

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.

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

References

External links

NBC NewsType strain of ''Elizabethkingia meningoseptica'' at Bac''Dive'' - the Bacterial Diversity Metadatabase
{{Taxonbar, from=Q3266416 Flavobacteria Bacteria described in 2005