From personalmd.com.
Adam Brochert, M.D.
February 21, 2009

As you may know, we all have millions of bacteria in our gastrointestinal tracts, primarily in the colon (or "large" bowel). These bacteria are important for normal bowel health and function. Klebsiella is the genus name for one of these bacteria. When Klebsiella bacteria get outside of the gut, however, serious infection can occur.

As a general rule, Klebsiella infections tend to occur in people with a weakened immune system. Many of these infections are obtained when a person is in the hospital for some other reason. The most common infection caused by Klebsiella bacteria outside the hospital is pneumonia.

Klebsiella pneumonia tends to affect people with underlying diseases, such as alcoholism, diabetes and chronic lung disease. Classically, Klebsiella pneumonia causes a severe, rapid-onset illness that often causes areas of destruction in the lung.

Infected persons generally get high fever, chills, flu-like symptoms and a cough productive of a lot of mucous. The mucous (or sputum) that is coughed up is often thick and blood tinged and has been referred to as "currant jelly" sputum due to its appearance.

Mortality in Klebsiella pneumonia is fairly high due to the underlying disease that tends to be present in affected persons. While normal pneumonia frequently resolves without complication, Klebsiella pneumonia more frequently causes lung destruction and pockets of pus in the lung (known as abscesses).

There may also be pus surrounding the lung (known as empyema), which can be very irritating to the delicate lung tissue and can cause scar tissue to form. At times, surgery may be needed to "rescue" a lung that is trapped in irregular pockets of pus and scar tissue.

Klebsiella can also cause less serious respiratory infections, such as bronchitis, which is usually a hospital-acquired infection. Other common hospital-acquired infections caused by Klebsiella are urinary tract infections, surgical wound infections and infection of the blood (known as bacteremia). All of these infections can progress to shock and death if not treated early in an aggressive fashion.

Many hospital-acquired infections occur because of the invasive treatments that are often needed in hospitalized patients. For example, intravenous catheters used for fluid administration, catheters placed in the bladder for urine drainage and breathing tubes for people on a breathing machine can all increase the susceptibility to infection.

While these devices may be needed in certain patients, they allow bacteria to bypass the natural barriers to infection and get into a persons body. The result may be an infection if the persons immune system cannot fight the bacteria. Unfortunately, the people who need invasive treatments often have weakened immune systems because of their underlying disease.

Klebsiella bacteria are generally resistant to many antibiotics, such as penicillin. Often, two or more powerful antibiotics are used to help eliminate a Klebsiella infection. Usually, a culture of the suspected infection site is required before a doctor can know that Klebsiella is the cause of the infection.

This may involve getting sputum samples (patients are asked to cough up phlegm into a jar), blood samples (using a needle to draw blood from a vein), urine samples or a swab (with a q-tip) of a surgical wound.

Once the samples are obtained, they are taken to a laboratory and put in a special substance which allows bacteria to grow (this is known as "culturing" the bacteria). If bacteria begin to grow, the lab can determine which type of bacteria it is.

If the bacteria are Klebsiella, the lab will need to run special tests to determine which antibiotics are best to treat the infection (this is known as sensitivity testing). This is important because different Klebsiella bacteria are resistant to different antibiotics, so what works for one Klebsiella infection may not work for another.

These culture and sensitivity tests may take two to three days to complete. A doctor may not wait for the test results to start antibiotics. Often, a powerful antibiotic or two is started right away once infection is suspected. The antibiotic can be switched a few days later if the results of the culture and sensitivity tests suggest a more appropriate drug to treat the infection.

Klebsiella bacteria are a part of normal life and live inside almost all of us. Although it is something we generally dont like to think about, we need Klebsiella in our colon to keep us healthy. Unfortunately, once Klebsiella escapes the gut, it can be one nasty bacteria.