What is klebsiella?

Updated November 21, 2016

Klebsiella pneumoniae can cause serious infections that may often be fatal. Drug-resistant pneumonia, chronic nasal infections, urinary tract infections, bronchitis and even gangrene are some of the infections these common bacteria can cause in susceptible people. Infections can spread rapidly and are most often acquired in the hospital while being treated for other illnesses or surgical procedures. The main sources of Klebsiella infections are the hands of hospital staff and the gastrointestinal tract of patients.


Named after the German bacteriologist Edwin Klebs (1834-1913), Klebsiella is a rod-shaped bacteria that lives in the mouth, skin and gastrointestinal tracts of humans and animals. Klebsiella is a member of the family of bacteria called Enterobacteriaceae. These bacteria are a normal part of our digestive tracts and cause us no harm when confined to the gastrointestinal system. When Klebsiella bacteria wind up in the lungs or other tissues, however, serious infection can result. Children and people with weakened immune systems are particularly vulnerable.


Klebsiella also occurs naturally in the soil. These strains of Klebsiella are beneficial because they carry out nitrogen fixation, a process critical to the completion of the nitrogen cycle. Klebsiella pneumoniae carry out nitrogen fixation as free living soil organisms. The majority of human infections are caused by Klebsiella pneumoniae and Klebsiella oxytoca.


The most common Klebsiella infection is pneumonia and it carries a 50 per cent mortality rate with it, even with antimicrobial treatment. Symptoms of Klebsiella pneumonia are flu-like symptoms, fever, chills and a cough with thick mucus tinged with blood. Klebsiella bacteria attack the lung tissue and can cause pus to surround the lung causing scar tissue to form. This is very serious and may require surgery to fix. Klebsiella also infects the urinary tract and can enter the body through wounds. Klebsiella is a leading cause of urinary tract infections in older patients, second only to E. coli.

Risk Factors

Contact with fecal matter is a significant source of infection. Hospitalised patients with invasive devices such as feeding tubes, indwelling catheters, central venous catheters and who are generally in poor health are at particular risk for contracting a Klebsiella infection. Those with alcoholism, lung disease and diabetes are also at risk. A Klebsiella infection may often need two powerful antibiotics as the bacteria are resistant to penicillin and many others, due to excessive use by hospitals of broad-spectrum antibiotics.


Klebsiella is mainly a nosocomial infection, which are hospital-acquired infections. If an infection appears 48 hours or more after hospital admission or within 30 days of discharge, it is considered to be nosocomial. Careful hand washing by medical staff before and after treating each patient is an effective way to avoid nosocomial infections.

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