Proteus

This page is about microbiologic aspects of the organism(s). For clinical aspects of the disease, see Proteus infection.

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Overview

Proteus is a urease-producing, motile, nitrite-reducing, hydrogen sulfide-producing, catalase-positive, facultatively anaerobic, Gram-negative bacillus. It can be found in soil, water, and fecal matter. It inhabits the intestinal tracts of humans and animals, and is considered an opportunistic pathogen of humans. Transmission to the human host (usually urinary tract) typically occurs via self-contamination.

Taxonomy

Kingdom: Bacteria; Phylum: Proteobacteria; Class: Gamma proteobacteria; Order: Enterobacteriales; Family: Enterobacteria; Genus: Proteus; Species: Proteus mirabilis

Genome

Proteus contains more than 3,658 coding sequences with 7 rRNA loci.^[1]
Total genome length is 4.063 Mb (28.8% GC content).^[1]
Proteus contains a single plasmid that contains 26,298 nucleotides.^[1]

Microbiological Characteristics

Proteus is a urease-producing, motile, nitrite-reducing, hydrogen sulfide-producing, catalase-positive, facultatively anaerobic, Gram-negative bacillus.
It grows optimally at 40 °C (104 °F).
It produces hydrogen sulfide gas, and forms clear films on growth media. It is motile, possessing peritrichous flagella, and is known for its swarming ability. It is commonly found in the intestinal tracts of humans. P. mirabilis is not pathogenic in guinea pigs or chickens.
Characteristically, Proteus can inhibit the growth of other strains in culture media, resulting in a macroscopically visible line (Dienes line) of reduced bacterial growth where two swarming strains intersect.
The following table summarizes the microbiological characteristics of Proteus:

Test	Result
Indole	Negative
Nitrate reductase	Positive (no formation of gas bubbles)
Methyl red	Positive
Voges-Proskauer	Negative (may be positive)
Catalase	Positive
Cytochrome oxidase	Negative
Phenylalanine deaminase	Positive
Tryptophan	Negative
Urea (Harnstoff test)	Positive
Casein	Negative
Starch	Negative
Hydrogen sulfide	Positive
Citrate agar	Negative
Ornithine decarboxylase	Positive
Lysine decarboxylase	Negative
Glucose fermentation	Positive
Amygdalin fermentation	Positive
Mannitol fermentation	Negative
Lactose fermentation	Negative

Natural Reservoir

Proteus can be found in soil, water, and fecal matter.
It inhabits the intestinal tracts of humans and animals, and is considered an opportunistic pathogen of humans.

Transmission

Proteus is usually transmitted to the human host by self-contamination (e.g. fecal material from gastrointestinal tract to genitourinary tract).

References

↑ ^1.0 ^1.1 ^1.2 Pearson MM, Sebaihia M, Churcher C, Quail MA, Seshasayee AS, Luscombe NM; et al. (2008). “Complete genome sequence of uropathogenic Proteus mirabilis, a master of both adherence and motility”. J Bacteriol. 190 (11): 4027–37. doi:10.1128/JB.01981-07. PMC 2395036. PMID 18375554.

[pmid18375554-1] 1.0 ^1.1 ^1.2 Pearson MM, Sebaihia M, Churcher C, Quail MA, Seshasayee AS, Luscombe NM; et al. (2008). “Complete genome sequence of uropathogenic Proteus mirabilis, a master of both adherence and motility”. J Bacteriol. 190 (11): 4027–37. doi:10.1128/JB.01981-07. PMC 2395036. PMID 18375554.

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