Proteus Vulgaris is a Gram negative bacilli shaped bacterium with an extracytoplasmic outer membrane that is believed to cause serious infections in humans. It is a part of the Enterobacteriaceae family as well as Escherichia coli, Klebsiella pneumonia, Enterobacter cloacae, and Serratia marcescens. The Proteus species in general is usually found in the intestinal flora of the intestinal tract, but also in nursing homes, assisted living residences, hospitals, soil, water and plants as well. In hospitals and long care facilities, Proteus finds its way into the patients and employees by the skin and oral mucosa. Proteus mirabilis is the culprit of 90% of all Proteus infections and can be classified as a community acquired infection.
“Infection depends on the interaction between the infecting organism and the host defense mechanisms. Various components of the membrane interplay with the host to determine virulence.” Another important factor in infection is the positive correlation of its size. Actually being infected with a bacterium is a process. The first step of that process it the virus/ bacteria infecting the host cell/ tissue. Once the tissue has been infected, the bacterium has to adhere to it using pili and chemical receptors. Once the bacterium is completely adhered, chemical messengers are sent out as a response, usually causing an infection. Certain chemicals in the body will react with bacteria to form different infections. For example, urease production coupled with bacteria can cause UTI’s (urinary tract infections). Proteus vulgaris is associated with about 35% of all urinary tract infections. “The ability of Proteus organisms to produce urease and to alkalinize the urine by hydrolyzing urea to ammonia makes it effective in producing an environment in which it can survive.”
Proteus vulgaris also has distinct characteristics that set it apart from other Gram negative bacteria. One feature is that they are very motile and literally “swarm” across the plate. This causes a thin film to form on top of the bacteria and a slight color change occurs. There are periods of rest in this “swarm” where they have to slow down and grow and divide. Since they only slow down, and not completely stop, this period of rest is called “swimming”. The other feature that they possess is the ability to turn urea into ammonia using urease. When this reaction occurs, and urease is utilized, the color of the medium changes from red to yellow.