Collection: Bacterial Infections

Bacterial Infections can result in swelling, pain, heat, redness, and loss of function

Bacterial infections are caused by the presence and growth of microorganisms that damage host tissue. The extent of infection is generally determined by how many organisms are present and the toxins they release. Worldwide, bacterial infections are responsible for more deaths than any other cause. Symptoms can include inflammation and swelling, pain, heat, redness, and loss of function. The most important risk factors are burns, severe trauma, low white blood cell counts, very old or young patients, patients on immunotherapy treatment, and anyone with malnutrition or vitamin deficiency. Bacteria are generally spread from an already infected person to the newly infected person. The most common invasion routes are inhalation of airborne bacteria, ingestion into the stomach from dirty hands or utensils, or through contaminated food or water, direct contact with an infected area of another person's body, contaminated blood, and insect bites. 

Bacteria consist of only a single cell, but don't let their small size and seeming simplicity fool you. They're an amazingly complex and fascinating group of creatures. Bacteria have been found that can live in temperatures above the boiling point and in the cold that would freeze your blood. They "eat" everything from sugar and starch to sunlight, sulfur, and iron.

There are thousands of species of bacteria, but all of them are basically one of three different shapes. Some are rod- or stick-shaped and called bacilli (buh-sill-eye).

Others are shaped like little balls and called cocci (cox-eye). Others still are helical or spiral in shape.

Some bacterial cells exist as individuals while others cluster together to form pairs, chains, squares, or other groupings.

A type of bacteria that tends to attack persons who are already ill or hospitalized is called Pseudomonas aeruginosa. Pseudomonas aeruginosa is a rod-shaped organism that can be found in soil, water, plants, and animals. Because it rarely causes disease in healthy persons but infects those who are already sick or who have weakened immune systems, it is called an opportunistic pathogen. Opportunistic pathogens are organisms that do not ordinarily cause disease but multiply freely in persons whose immune systems are weakened by illness or medication. Such persons are said to be immunocompromised. Pseudomonas aeruginosa, the versatile "blue-green pus bacteria" opportunistically infect people, especially those who are immunocompromised. Pseudomonas rarely causes infection in healthy individuals but it is a major cause of hospital-acquired (nosocomial) infections. It tends to infect people with immunodeficiency or burns and those with indwelling catheters or respirators. Infection with pseudomonas can lead to urinary tract infections, sepsis (bloodstream infection), pneumonia, pharyngitis, and many other medical problems. Pseudomonas colonizes the lungs of patients with cystic fibrosis (CF) and contributes to the chronic progressive pulmonary disease and death rate in CF.

Several factors make it a strong opponent. These factors include:

  • the ability to stick to cells
  • minimal food requirements
  • resistance to many antibiotics
  • production of proteins that damage tissue
  • a protective outer coat

How Does the Immune System fight Bacterial Infections?

The immune system is a body-wide network of cells and organs that has evolved to defend the body against attacks by foreign entities such as bacteria, fungi, parasites, and viruses.