Klebsiella pneumoniae Invasive Syndrome without Liver Abscess: A Case Report

Area of Science:

• Infectious Diseases
• Microbiology
• Clinical Medicine

Background:

• Klebsiella pneumoniae invasive syndrome (KPIS) is a severe, multi-site infection with high mortality, often caused by hypervirulent Klebsiella pneumoniae.
• While historically concentrated in East Asia, KPIS incidence is increasing globally, including in Western countries.
• The condition typically requires prolonged antimicrobial treatment.

Purpose of the Study:

• To report a case of KPIS in an immunocompetent Indian man.
• To highlight diagnostic challenges and the utility of the string test in identifying hypervirulent strains.
• To emphasize that KPIS should be considered in unexplained systemic inflammation with multifocal abscesses.

Main Methods:

• Case report of a 45-year-old Indian man presenting with fever, back pain, arthralgia, hemiparesis, and slurred speech.
• Diagnostic workup included laboratory tests (leukocyte count, ESR, CRP), brain MRI, and PET-CT.
• Cultures of vertebral abscess confirmed Klebsiella pneumoniae with a positive string test.

Main Results:

• Brain MRI revealed multiple hemorrhagic lesions, while PET-CT identified septic collections in the spleen, kidney, knee, vertebrae, and abscesses.
• Klebsiella pneumoniae was isolated from vertebral abscess cultures, exhibiting a hypermucoviscous phenotype via a positive string test.
• The patient received 6 weeks of antibiotics, initially vancomycin and gentamicin, then de-escalated to amoxicillin-clavulanic acid.

Conclusions:

• KPIS can manifest in immunocompetent individuals and presents as unexplained systemic inflammation with multifocal abscesses.
• Hepatic involvement, though characteristic, is not mandatory for KPIS diagnosis.
• A positive string test serves as a valuable surrogate for identifying hypervirulent Klebsiella pneumoniae strains when genotypic analysis is inaccessible.