Is Klebsiella a Common Skin Contaminant?
No, Klebsiella is not a common skin contaminant—it is a pathogenic colonizer that can cause true infections, not a typical contaminant organism.
Klebsiella as a Skin Colonizer vs. Contaminant
Klebsiella species colonize intact skin in specific patient populations and clinical contexts, representing true pathogenic potential rather than benign contamination. 1
Klebsiella spp. can be recovered from intact areas of normal patient skin at concentrations ranging from 100 to 10^6 CFU/cm², particularly in the perineal, inguinal, axillary, trunk, and upper extremity regions 1
Healthcare workers can contaminate their hands with 100-1,000 CFUs of Klebsiella spp. during routine "clean" patient care activities such as lifting patients, taking vital signs, or touching the patient's hand, shoulder, or groin 1
This organism survives on hands and environmental surfaces, facilitating healthcare-associated transmission—a characteristic of true pathogens, not contaminants 1
Clinical Significance in Skin and Soft Tissue Infections
Klebsiella is recognized as a true pathogen in complicated skin and soft tissue infections (cSSTIs), not a contaminant to be dismissed. 2, 3, 4
In a large North American surveillance study, Klebsiella spp. accounted for 5.1-5.8% of cSSTI isolates, ranking as the fifth most common pathogen 2
Klebsiella species (particularly K. pneumoniae) are specifically listed as causative agents of skin and skin-structure infections in FDA-approved drug labeling for antibiotics 5
Necrotizing fasciitis can be caused by Klebsiella species, though less commonly than streptococci or MRSA 3, 4, 3
Case reports document Klebsiella pneumoniae causing pustules and skin ulcers in occupational exposures (e.g., aquaculture workers) 6
Key Distinction: Pathogen vs. Contaminant
The critical distinction is that Klebsiella represents colonization with pathogenic potential, not benign contamination like coagulase-negative staphylococci. 1
True skin contaminants (e.g., coagulase-negative staphylococci, diphtheroids) are part of normal skin flora with minimal pathogenic potential 1
Klebsiella is an opportunistic pathogen that colonizes skin secondarily, particularly in hospitalized patients, those with diabetes, chronic renal failure patients on dialysis, and those with chronic dermatitis 1
When Klebsiella is isolated from properly collected deep tissue specimens (not surface swabs), it should be considered a true pathogen requiring treatment 3, 4, 3
Clinical Implications for Specimen Interpretation
Surface swab cultures showing Klebsiella may represent colonization rather than infection, but deep tissue cultures warrant treatment. 3, 4, 3
Surface cultures of wounds and decubitus ulcers are not valuable because they cannot differentiate colonizing microbes from underlying etiologic agents 3, 4, 3
Tissue biopsies after thorough debridement or bone biopsies are most valuable for determining true infection 3, 4, 3
The presence of Klebsiella in blood cultures, deep tissue specimens, or properly collected wound cultures indicates true infection requiring antimicrobial therapy 1, 5
Common Pitfall to Avoid
Do not dismiss Klebsiella as a "contaminant" when isolated from clinical specimens—this organism has significant pathogenic potential and antimicrobial resistance concerns. 2, 7, 8
Klebsiella species are intrinsically resistant to penicillins and can acquire resistance to third- and fourth-generation cephalosporins through ESBL production 2, 7
ESBL-producing Klebsiella infections are associated with higher treatment failure rates (35% vs. 15% for non-ESBL strains) and increased mortality 2
The organism's thick capsule makes it difficult to treat, requiring appropriate antimicrobial selection based on susceptibility testing 7, 9