Is Klebsiella pneumoniae a Common Bacterium?
Yes, Klebsiella pneumoniae is a common bacterium, particularly in healthcare settings where it ranks among the most frequently isolated pathogens causing hospital-acquired infections. 1
Healthcare-Associated Prevalence
K. pneumoniae is one of the most common causes of hospital-acquired infections, ranking third among gram-negative pathogens in nosocomial pneumonia surveillance data at 11.6% of cases 1
In healthcare settings, K. pneumoniae causes multiple infection types including ventilator-associated pneumonia, urinary tract infections, bloodstream infections, and intra-abdominal infections 1
Colonization rates in hospitalized patients are substantial, with rectal colonization prevalence documented at 23.0% among screened patients 2
The bacterium is particularly common in intensive care units and among immunocompromised populations, including neutropenic cancer patients where Klebsiella species are listed among the most common gram-negative pathogens 1
Community vs. Healthcare Settings
K. pneumoniae is uncommon as a cause of community-acquired pneumonia in the general population, except in specific high-risk groups such as alcoholics 3
However, community-acquired infections are increasingly reported, particularly with hypervirulent strains that can cause severe infections including liver abscess, meningitis, and endophthalmitis in previously healthy individuals 4
The epidemiology is shifting, with ESBL-producing K. pneumoniae emerging as a problem in outpatient settings in various parts of the world, threatening to introduce resistant strains into hospitals 1
Antimicrobial Resistance Patterns
Carbapenem-resistant K. pneumoniae (CRKP) has become increasingly common, rising from fewer than 1% of all Klebsiella isolates in 2000 to 8% by 2007 in U.S. healthcare-associated infection surveillance 1
CRKP is now the most commonly encountered carbapenem-resistant Enterobacteriaceae species in the United States 1
The bacterium serves as a major reservoir and shuttle for antibiotic resistance, continuously accumulating resistance genes through plasmids and mobile genetic elements 5
Clinical Significance
K. pneumoniae infections are associated with high morbidity and mortality, particularly ESBL-producing and carbapenem-resistant strains which show treatment failure rates of 35% at 72 hours compared to 15% for susceptible strains 1
Environmental contamination facilitates transmission, as K. pneumoniae can survive on hospital surfaces (door knobs, hand rails) and colonize medical equipment including catheters and ventilators 6
Colonization directly predicts infection risk: colonized patients have a 4-fold increased odds of developing extraintestinal infection (adjusted OR 4.01,95% CI 2.08-7.73), with genomic analysis confirming that infecting strains match colonizing strains in 93% of cases 2