Proteus intestinal bacteria

2021-08-20 11:08 PM

The antigenic structure of Proteus is very complex. A special correlation was found between the O antigens of some strains of Proteus

The genus Proteus is parasitic in the intestines and natural cavities of humans (eg, in the external ear canal). They are “opportunistic” bacteria.

Biological characteristics


Gram-negative bacilli, very mobile. Bacteria have many different shapes on different media, from bacilli to long filaments.

Viral Culture properties

Bacteria grow readily on common culture media. On nutrient agar, colonies have a center that spreads out gradually, in waves, in waves, each wave is a ripple and has a distinctive rotten smell.

On sodium deoxycholate medium: Proteus grows in isolated, round, non-ripple colonies with a central black spot, surrounded by off-white color.

Biochemical properties

 Do not ferment lactose. Majority of Proteus: H2S positive and urease positive. Based on the biological and chemical properties, people classify the genus Proteus into species: Proteus mirabilis, Proteus vulgaris, Proteus myxofaciens, Proteus penneri.

Antigen structure

The antigenic structure of Proteus is very complex and cannot be used in daily practice. There is a particular correlation between the O antigen of some strains of Proteus (called OX2; OX19; OXK) and Rickettsia. Therefore, these strains are used as antigens in serological diagnosis of Rickettsial diseases (Weil-Felix reaction).

Possibility to cause disease

Proteus is an "opportunistic pathogen". They can cause:

Purulent otitis media

Meningitis is secondary to medial inflammation in nursing infants.

Urinary tract infections.

Sepsis ...

Microbiological diagnosis

Isolation of bacteria from samples such as: ear pus, urine, blood ... depending on the clinical disease. The lesions and pus caused by Proteus have a rotten odor similar to that of gangrene caused by anaerobic bacteria. Cultured on conventional media. Bacterial identification is based on wavy colony morphology, distinctive rotten odor on media plates and urease-positive Gram-negative bacilli, and some other biochemical properties.

To isolate into separate colonies, culture on medium containing sodium desoxycholate, Proteus will grow into separate colonies with black dots in the center after 48 hours.

Prevention and cure


To improve the patient's condition, when applying examination procedures, they must be absolutely sterile to prevent hospital infections.


 Antibiotic use is based on the results of the antibiogram. This bacterium is usually highly resistant to antibiotics.