Proteus Vulgaris: Introduction, Identification Features, Keynotes, and Proteus Footages

The genus Proteus was discovered in 1885 by Hauser and it is also named after a Greek god.  Proteus is a member of the family, Enterobacteriaceae and it is a Gram-negative, oxidase-negative, fimbriated, motile, non-sporing rod-shaped bacterium without capsule and having a size of 0.4–0.8 μm in diameter and 1.0–3.0 μm in length. Proteus vulgaris is naturally found in the natural environment and also in the intestinal tract. It is a gut bacterium inside our intestines whereas, outside the gut, it can cause serious infections. It is an etiological agent of catheter-associated UTI (CAUTI), sepsis, and septic shock if the infection goes up and causes cystitis and pyelonephritis.

Biochemical Reactions of Proteus vulgaris

Basic FeaturesProperties
1. Gram StainingGram-Negative Rods (GNRs)
2. SporeNon-Sporing
3. CapsuleNegative
4. MotilityMotile
5. PigmentNegative
6. Growth in potassium cyanide (KCN) mediumPositive
7. Catalase testPositive
8. Oxidase testNegative
9. Nitrate reduction testPositive
10. MR (Methyl Red) testPositive
11. VP (Voges- Proskauer) assayNegative
12. OF (Oxidative-Fermentative) testFermentative (facultative anaerobes)
13. Gas from GlucosePositive
14. H2S productionPositive
15. Indole formationNegative
16. Urease/ urea hydrolysis testPositive
17. Citrate/citrate utilizationPositive
18. DNase testVariable
19. Glucose fermentationPositive 
20. Maltose fermentationNegative
21. Lactose fermentationNegative
22. Sucrose fermentationNegative
23. Xylose fermentationPositive
24. Mannitol fermentationNegative
25. Acetate UtilizationNegative
26. ONPG (β-galactosidase)Negative
27. Phenylalanine Deaminase (PDA)/PPA TestPositive
28. Lipase testPositive
29. Esculin Hydrolysis testNegative
30. Lysine Decarboxylase TestNegative
31. Ornithine Decarboxylase TestPositive
32. Arginine Dihydrolase TestNegative
33. Gelatin HydrolysisPositive
34. Tryptophan DeaminaseNegative
35. Casein HydrolysisNegative
Table: Identification Features of Proteus vulgaris

Keynotes on Proteus

  • In Greek mythology, Proteus means sea god.
  • Every year about 150 million people are affected by Proteus mirabilis globally.
  • It is the bacterium of concern since, in the USA, it accounts for about 3% of all hospital infections and 44% of CAUTI.
  • The principal virulence factors associated with infection are flagella, pili, urease, hemolysin, and metal intake.
  • Multiple drug-resistant (MDR) strains to carry R plasmids have become very important in nosocomial infections.
  • The distinctive characteristics of the genus are PPA, urease, and  H2S positive.
  • Indole helps to differentiate P. vulgaris (positive) from P. mirabilis ( negative).
  • Dienes phenomenon or typing is used successfully to determine the relationship between strains of Proteus species in studies of cross-infection.
  • The swarming growth of Proteus contains swimmer and swarmer cells and these cells can be determined using Gram’s staining i.e. swimmer cells- small-near the center of the growth plate while swarmer cells- large-away the center of the growth plate as shown in footages.
  • The swarming growth of Proteus is inhibited by the following agents-
  1. Agar (6%)
  2. Sodium azide (NaN3) (1:500)
  3. Chloral hydrate (1:500)
  4. Boric acid (1:1000)
  5. Alcohol (5-6%)

Proteus Footages

Swarming growth of Proteus on blood agar

Swarming growth of Proteus on blood agar
Fig. Swarming growth of Proteus on blood agar

Proteus in Gram Staining

Proteus in Gram Staining
Fig. Proteus in Gram Staining

Proteus vulgaris Biochemical Tests-MIU, TSI, and Citrate Utilization Tests

Proteus vulgaris Biochemical Tests-MIU,TSI, and Citrate Utilization Tests
Fig. Proteus vulgaris Biochemical Tests-MIU, TSI, and Citrate Utilization Tests

Dienes phenomenon of Proteus vulgaris strains

Dienes phenomenon of Proteus vulgaris strains
Fig. Dienes phenomenon of Proteus vulgaris strains

Proteus mirabilis Biochemical Tests-MIU, TSI, and Citrate Utilization Tests

Proteus mirabilis Biochemical Tests-MIU,TSI, and Citrate Utilization Tests
Fig. Proteus mirabilis Biochemical Tests-MIU, TSI, and Citrate Utilization Tests

Further Reading

  1. https://jb.asm.org/content/195/6/1305
  2. https://www.karger.com/Article/FullText/514097
  3. https://www.annualreviews.org/doi/pdf/10.1146/annurev.mi.32.100178.000533
  4. https://universe84a.com/proteus-general-characteristics
  5. Williams FD, Schwarzhoff RH. 1978. Nature of the swarming phenomenon in Proteus. Annu. Rev. Microbiol. 32:101–122.
  6. https://www.sciencedirect.com/topics/medicine-and-dentistry/proteus-mirabilis
  7. Armbruster CE, Mobley HLT. 2012. Merging mythology and morphology: the multifaceted lifestyle of Proteus mirabilis. Nat. Rev. Microbiol. 10:743–754
  8. Morgenstein RM, Szostek B, Rather PN. 2010. Regulation of gene expression during swarmer cell differentiation in Proteus mirabilis. FEMS Microbiol. Rev. 34:753–763.
  9. Rather PN. 2005. Swarmer cell differentiation in Proteus mirabilis. Environ. Microbiol. 7:1065–1073.
  10. Bailey & Scott’s Diagnostic Microbiology. Editors: Bettey A. Forbes, Daniel F. Sahm & Alice S. Weissfeld, 12th ed 2007, Publisher Elsevier.
  11. Clinical Microbiology Procedure Handbook, Chief in editor H.D. Isenberg, Albert Einstein College of Medicine, New York, Publisher ASM (American Society for Microbiology), Washington DC.
  12. Colour Atlas and Textbook of Diagnostic Microbiology. Editors: Koneman E.W., Allen D.D., Dowell V.R. Jr, and Sommers H.M.
  13.  Textbook of Diagnostic Microbiology. Editors: Connie R. Mahon, Donald G. Lehman & George Manuselis, 3rd edition 2007, Publisher Elsevier
  14. Jawetz, Melnick and Adelberg’s Medical Microbiology. Editors: Geo. F. Brook, Janet S. Butel & Stephen A. Morse, 21st ed 1998, Publisher Appleton & Lance, Co Stamford Connecticut.
  15. Mackie and Mc Cartney Practical Medical Microbiology. Editors: J.G. Colle, A.G. Fraser, B.P. Marmion, A. Simmous, 4th ed, Publisher Churchill Living Stone, New York, Melborne, Sans Franscisco 1996.
  16.  Manual of Clinical Microbiology. Editors: P.R. Murray, E. J. Baron, M. A. Pfaller, F. C. Tenover and R. H. Yolken, 7th ed 2005, Publisher ASM, USA

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