Proteus vulgaris characteristics, morphology, contagion, symptoms

Proteus vulgaris is a species of rod-shaped gram-negative bacteria (bacillus) that belongs to the group of Enterobacteriaceae. It is normally present in the fecal flora of humans, but it is also common in urinary tract infections of the young and old.

The genus name Proteus It comes from the name of a Greek sea god who was able to change his form voluntarily. This genus is represented in five species: P. mirabilis, P. vulgaris, P. penneri, P. hauseri Y P. myxofaciens. The latter is the only one of the genus that is not pathogenically important for humans..

Most of the members of the genus are found in the intestine, although others are typical in the soil and freshwater deposits. Proteus vulgaris, however, it is a facultative or “opportunistic” pathogen, since it causes disease in susceptible hosts..

The group of bacteria Proteus It was described more than 100 years ago by Hauser. It is characterized by presenting a pleomorphic morphology (with many forms). P. vulgaris Y P. mirabilis, specifically, they present a characteristic “swarm motility” in a solid medium..

Along with bacteria of the genera Escherichia, Klebsiella, Enterobacter, and Serratia, bacteria of the genus Proteus are linked to numerous cases of serious human infections.

Article index

• 1 Characteristics and morphology
• 2 How is it spread?
• 3 Symptoms
• 4 Treatments
• 5 References

Characteristics and morphology

Like all gram-negative bacteria, bacteria of the genus Proteus are characterized by the presence of a covering composed of two lipid membranes between which is a thin peptidoglycan network.

The outer membrane of these bacteria contains a lipid bilayer rich in characteristic lipoproteins, polysaccharides, and lipopolysaccharides. In addition, they are covered by fimbriae that allow them to adhere to the host's tissues..

Like the other species of the genus Proteus, P. vulgaris characterized by its swarming activity, which appears macroscopically in a solid culture as concentric growth rings arising from a single colony or the initial inoculum.

This form of growth occurs thanks to the differentiation of cells in liquid medium, which once they come into contact with a solid medium such as agar, change in size, lengthening their shape and increasing the synthesis of flagellin..

Individuals belonging to this species are generally sensitive to nalidixic acid, ciprofloxacin and ceftriaxone, with an intermediate sensitivity to nitrofurantoin.

The production of cytotoxic hemolysins is common in this species, which has been extensively studied, especially regarding the genetic and molecular bases of its secretion..

How is it spread?

They are opportunistic pathogenic bacteria, especially associated with upper urinary tract infections such as urolithiasis, which is the formation of stones in the kidney or bladder, urethritis, prostatitis, cystitis and acute pyelonephritis..

Brain abscesses have also been described as forms of bacterial infection caused by P. vulgaris in humans.

P. vulgaris, as well as other pathogenic bacteria of the genus it is a common resident not only of the intestinal flora, but also of long-term healthcare facilities, hospitals and clinics.

The most common form of contagion is accidental, and it occurs in patients who have undergone surgeries before or after which require bladder or urethral catheterization. Usually these bacilli are also capable of colonizing both the serous secretions of the skin and the oral mucous membranes..

Nosocomial infections associated with hospitals and patients who receive medical care and whose immune system is compromised, that is, who are more susceptible, are then the most common to P. vulgaris and related species.

Symptoms

When the body comes into contact with pathogenic bacteria, specifically when the bacteria adhere to uroepithelial cells, numerous response events are initiated in the endothelial mucous cells, among which are the secretion of interleukins and activation of programmed cell death, among others..

Endotoxins present in the cell membrane also trigger cascades of inflammatory responses in the host, causing physical discomfort..

P. vulgaris and other similar bacteria of the genus are capable of producing ureases, alkalizing urine by hydrolyzing urea to produce ammonia. Other symptoms include flank pain and hematuria, which has to do with reddish urine..

Treatments

Depending on the degree of complication of the infections, the treatments may vary. For women with uncomplicated infections, empirical treatments suggest the use of oral quinolone or sulfamethoxazole for no more than a couple of days..

When it comes to symptoms of cases of acute infection, quinolones are also used, but for longer times, or some third generation antibiotics such as ceftriaxone, the use of gentamicin, oral cephalosporin, ampicillin and aztreonam is also recommended..

Cases of kidney stones produced by bacterial infections with species of the genus Proteus often require surgical removal.

Similarly, those cases of non-urological infections that result in abscesses merit surgical cleaning treatments for their effective eradication..

References

1. Alberts, B., Johnson, A., Lewis, J., Morgan, D., Raff, M., Roberts, K., & Walter, P. (2015). Molecular Biology of the Cell (6th ed.). New York: Garland Science.
2. González, G. (2018). Proteus Infections Clinical Presentation. Retrieved from www.emedicine.medscape.com/article/226434-clinical
3. Hickman, F. W., Steigerwalt, A. G., Farmer, J. J., Brenner, D. O. N. J., Control, D., & Carolina, N. (1982). Identification of Proteus penneri sp. nov., Formerly Known As Proteus vulgaris Indole Negative or As Proteus vulgaris Biogroup 1, fifteen(6).
4. Koronakis, V., Cross, M., Senior, B., Koronakis, E. V. A., & Hughes, C. (1987). The Secreted Hemolysins of Proteus mirabilis, Proteus vulgaris, and Morganella morganii Are Genetically Related to Each Other and to the Alpha-Hemolysin of Escherichia coli. Journal of Bacteriology, 169(4), 1509-1515.
5. Koronakis, V., & Hughes, C. (1988). Identification of the promotors directing in vivo expression of hemolysin genes in Proteus vulgaris and Escherichia coli. Mol. Gen. Genet., 213, 99-104.
6. Mohammed, G. J., Kadhim, M. J., & Hameed, I. H. (2016). Proteus species: Characterization and Herbal Antibacterial: A Review. International Journal of Pharmacognosy, 8(11), 1844-1854.
7. Myrvik, Q., Pearsall, N., & Weiser, R. (1977). Medical Bacteriology and Mycology (1st ed.). Mexico D.F .: Interamericana.