Klebsiella is a genus of Gram-negative, rod-shaped bacteria from the Enterobacteriaceae family, with Klebsiella pneumoniae being the most common species affecting humans. A prominent feature is their thick, polysaccharide-based capsule, which protects the cell from the body’s defense mechanisms.
Klebsiella bacteria are found in soil and water and are also a normal part of the human intestines, mouth, and skin. In healthy individuals, these bacteria are harmless. However, Klebsiella is an opportunistic pathogen, causing infections if it spreads to other body parts, especially in people with weakened immune systems.
Common Klebsiella-Associated Infections
When Klebsiella pneumoniae moves outside the gut, it can cause infections in various body systems, frequently in healthcare settings. Pneumonia is a common infection, presenting with sudden high fever, chills, and flu-like symptoms. This pneumonia can lead to a cough producing thick, bloody mucus sometimes described as “currant jelly sputum.”
Klebsiella can cause urinary tract infections (UTIs) with symptoms like a frequent urge to urinate, a burning sensation, and pelvic pain. If the infection reaches the kidneys, it may cause fever and back pain. The bacteria can also enter wounds from injury or surgery, causing skin infections with redness, pain, and pus.
The bacteria can cause bloodstream infections (bacteremia or sepsis), leading to fever, chills, and a rapid heart rate. A less common infection is meningitis, an inflammation of the membranes around the brain and spinal cord, causing a stiff neck, severe headache, and confusion. Hypervirulent strains of K. pneumoniae are associated with pyogenic liver abscesses—collections of pus in the liver—and can cause infections even in healthy individuals.
Transmission Routes and At-Risk Populations
Klebsiella infections are frequently acquired in healthcare environments. The bacteria are not airborne, and transmission occurs through direct person-to-person contact. A primary route is via the contaminated hands of healthcare workers moving between patients.
Spread also occurs through indirect contact with contaminated medical equipment like ventilators and catheters, which create entry points into the body. Pneumonia can occur if a patient aspirates secretions containing the bacteria into their lungs. The gastrointestinal tract of patients is a major reservoir for the organism, facilitating its spread in hospitals.
Certain groups are more vulnerable to Klebsiella infections. People at elevated risk include:
- Hospitalized patients, especially those in intensive care units (ICUs) or long-term care facilities.
- Individuals with weakened immune systems from conditions like diabetes, alcoholism, or treatments like chemotherapy.
- Those with invasive medical devices, recent surgical sites, or open wounds.
- People on long-term antibiotic courses, which can disrupt protective gut flora.
Diagnosis, Treatment, and Antibiotic Resistance
Diagnosis involves assessing a patient’s symptoms and may include imaging tests like a chest X-ray for pneumonia. A definitive diagnosis requires lab analysis of a clinical sample, such as sputum, urine, blood, or a wound swab. The sample is cultured to isolate and identify the bacteria.
Treatment for Klebsiella infections relies on antibiotics, with the specific choice depending on the infection’s site and severity. Lab testing is performed on the cultured bacteria to determine which drugs will be effective. For severe infections like liver abscesses, treatment may also require draining the abscess alongside a prolonged course of antibiotics.
A significant challenge is the bacterium’s ability to develop antibiotic resistance. Some strains produce enzymes called extended-spectrum beta-lactamases (ESBLs), which inactivate common antibiotics like penicillins.
An even greater concern is carbapenem-resistant Enterobacteriaceae (CRE), which includes Klebsiella. These bacteria produce enzymes like Klebsiella pneumoniae carbapenemase (KPC) that destroy carbapenem antibiotics, often a last-resort treatment. CRE infections are difficult to treat, leading to limited options and higher rates of illness and death.
Preventive Measures Against Klebsiella
Preventing the spread of Klebsiella is a priority in healthcare facilities. Strict hand hygiene for all healthcare personnel is the primary measure to prevent transmission between patients. This includes washing hands with soap and water or using an alcohol-based hand sanitizer before and after each patient interaction.
Infection control protocols include contact precautions for patients with multidrug-resistant Klebsiella. Healthcare workers wear gowns and gloves during patient care to minimize spread. Thorough cleaning and disinfection of patient rooms and medical equipment also reduce environmental contamination.
Another strategy is the careful management of invasive medical devices. Catheters and ventilators should only be used when necessary and removed as soon as possible. Some hospitals also screen high-risk patients upon admission to identify carriers of resistant strains and implement control measures.
Antibiotic stewardship programs also play a role in prevention. These programs ensure antibiotics are used appropriately: only when needed, with the right drug, at the correct dose, and for the proper duration. This approach helps slow the development of antibiotic resistance in Klebsiella and other bacteria.