''Alcaligenes faecalis'' is a species of
Gram-negative
Gram-negative bacteria are bacteria that, unlike gram-positive bacteria, do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. Their defining characteristic is that their cell envelope consists ...
, rod-shaped bacteria commonly found in the environment. It was originally named for its first discovery in
feces
Feces (also known as faeces American and British English spelling differences#ae and oe, or fæces; : faex) are the solid or semi-solid remains of food that was not digested in the small intestine, and has been broken down by bacteria in the ...
, but was later found to be common in soil, water, and environments in association with humans. While
opportunistic infection
An opportunistic infection is an infection that occurs most commonly in individuals with an immunodeficiency disorder and acts more severe on those with a weakened immune system. These types of infections are considered serious and can be caused b ...
s do occur, the
bacterium
Bacteria (; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among the ...
is generally considered nonpathogenic. When an opportunistic infection does occur, it is usually observed in the form of a urinary tract infection.
''A. faecalis'' has been used for the production of
nonstandard amino acids.
Description
''A. faecalis'' is a Gram-negative bacterium which appears
rod-shaped
Bacterial cellular morphologies are the shapes that are characteristic of various types of bacteria and often key to their identification. Their direct examination under a light microscope enables the classification of these bacteria (and archae ...
and motile under a microscope. It is positive by the
oxidase test and
catalase test, but 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 ...
. It is
alpha-hemolytic and
requires oxygen. ''A. faecalis'' can be grown at 37 °C, and forms colonies that lack pigmentation.
Metabolism
The bacterium degrades
urea
Urea, also called carbamide (because it is a diamide of carbonic acid), is an organic compound with chemical formula . This amide has two Amine, amino groups (–) joined by a carbonyl functional group (–C(=O)–). It is thus the simplest am ...
, creating ammonia which increases the pH of the environment. Although ''A. faecalis'' is considered to be alkali-tolerant, it maintains a neutral pH in its cytosol to prevent the damaging or denaturing of its charged species and macromolecules.
[
]
History
''A. faecalis'' may have been isolated by Johannes Petruschky in 1896, and also described (and they state, the description corrected) in 1919 by Castellani and Chalmers.[ ''A. faecalis phenolicus'' is distinguished by its ability to use ]phenol
Phenol (also known as carbolic acid, phenolic acid, or benzenol) is an aromatic organic compound with the molecular formula . It is a white crystalline solid that is volatile and can catch fire.
The molecule consists of a phenyl group () ...
as a carbon source.[
]
Research
In 2024, researcher Ellen White of the University of Pennsylvania
The University of Pennsylvania (Penn or UPenn) is a Private university, private Ivy League research university in Philadelphia, Pennsylvania, United States. One of nine colonial colleges, it was chartered in 1755 through the efforts of f ...
found that ''Alcaligenes faecalis'' can help treat chronic wounds heal faster. White added ''A. faecalis'' to wounds on diabetic mice and to human skin samples from people with diabetes while adding ''A. faecalis''. The results showed the wounds treated with the bacteria healed faster and produced keratinocytes
Keratinocytes are the primary type of cell found in the epidermis, the outermost layer of the skin. In humans, they constitute 90% of epidermal skin cells. Basal cells in the basal layer (''stratum basale'') of the skin are sometimes refer ...
.
References
External links
Type strain of ''Alcaligenes faecalis'' at Bac''Dive'' - the Bacterial Diversity Metadatabase
Burkholderiales
Bacteria described in 1919
{{Betaproteobacteria-stub