Klebsiella are ubiquitous Gram-negative, non-motile bacteria within the Enterobacteriaceae family, which includes well-studied human pathogens like Escherichia, Salmonella, Shigella and Yersinia.
Typically a GI pathogen, with the reservoir leading to human infection being the person's own gut.
Hypermucoviscous (HMV) and hypervirulent are often used synonymously in the literature; however, not all patients with a hypervirulent phenotype have hypermucoviscous bacteria and not all hypermucoviscous isolates lead to an invasive syndrome
- Increased virulence of hvKp over classical (cKp)
- Capable of causing severe organ and life threatening disease.
- Tendency for metastatic spread of disease.
- Increasing prevalence over time, especially in Asia
Hypervirulent vs classic KP
| Parameter | hvKP | cKP |
|---|---|---|
| Location for the development of infection | More commonly the community | More commonly a health care setting |
| Host | All ages; often otherwise healthy | Older, with some form of compromise |
| Ethnic background | Often Asian, Pacific Islander, Hispanic | No ethnic predilection |
| Hepatic abscess | Usually occurs in the absence of biliary disease | Usually occurs in the presence of biliary disease |
| Number of sites of infection | Often multiple | Usually single |
| Unusual infectious syndromes for K. pneumoniae | Endophthalmitis, meningitis, brain abscess, necrotizing fasciitis, splenic abscess, epidural abscess | None |
| Copathogens at the site of infection | Rare, usually monomicrobial | Not uncommon, especially with abdominal, soft tissue, or urinary catheter infection |
Clinical Manifestations
Suspect hvKp in serious infections especially in young and healthy individuals.
- Pyogenic liver abscesses/other abscesses
- Meningitis
- Endophthalmitis
- Nec fasc
Specific risk factors:
- Diabetes
- Younger, immunocompetent otherwise
- ?Asian/Chinese
Empiric Treatment
| Clinical syndrome or site of infection | Empiric antibiotic suggestions |
|---|---|
| Liver (or other intra-abdominal) abscess or pneumonia | β-lactam/β-lactamase inhibitors, third-generation cephalosporins, fluoroquinolones, carbapenems or aminoglycosides |
| Central nervous system infection | Third-generation cephalosporins or carbapenems |
| Endophthalmitis | Intravitreal antibiotics (cefazolin, ceftazidime, aminoglycosides or imipenem) plus intravenous antibiotics (variable, but usually cephalosporins) |
| Prostate abscess | Fluoroquinolones or trimethoprim-sulfamethoxazole |
References
- Hypervirulent Klebsiella pneumoniae | Clinical Microbiology Reviews (asm.org)
- Frontiers | Characteristics of Hypervirulent Klebsiella pneumoniae: Does Low Expression of rmpA Contribute to the Absence of Hypervirulence? | Microbiology (frontiersin.org)
- Hypervirulent Klebsiella pneumoniae – clinical and molecular perspectives - Choby - 2020 - Journal of Internal Medicine - Wiley Online Library