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Reliable, easy-to-read patient information on common medical conditions — written in plain language, free of jargon, and grounded in current evidence. Browse the most frequent diagnoses, understand what they mean for everyday life, and learn which steps and questions help you have a focused conversation with your doctor.

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Proteus

Introduction

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

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

Taxonomy

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

Genome

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

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

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

Transmission

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

References

  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.

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