[A case of endophthalmitis and abscesses in the liver and the lung caused by Klebsiella pneumoniae]

Cryptogenic invasive Klebsiella pneumoniae liver abscess syndrome

BACKGROUND

Klebsiella pneumoniae-associated liver abscesses have distinct clinical and epidemiologic features.

METHODS

We report the unusual case of an American patient with a K. pneumoniae-associated liver abscess and septic spread to other organs. We additionally present a comprehensive review of K. pneumoniae-associated liver abscess syndromes in adults.

RESULTS

We identified three distinct K. pneumoniae liver abscess syndromes: the polymicrobial liver abscess, the monomicrobial cryptogenic noninvasive liver abscess, and the monomicrobial cryptogenic invasive K. pneumoniae-associated liver abscess (CIKPLA) syndromes, with distinct clinical, epidemiologic and outcome features. CIKPLA syndrome typically affects diabetic patients, mainly in Southeast Asia, and is complicated by septic spread to other organs.

CONCLUSIONS

The community-acquired, monomicrobial, K. pneumoniae-associated liver abscess syndromes that typically occur in the USA are mainly noninvasive and affect Asian or Hispanic persons. However, this report provides an alert that CIKPLA syndrome can occur in North America, and physicians need to be aware of it.

Endogenous Endophthalmitis and Disseminated Intravascular Coagulation Complicating a Klebsiella pneumoniae Perirenal Abscess in a Patient with Type 2 Diabetes

We describe a 56-year-old woman with type 2 diabetes complicated by a Klebsiella pneumoniae perirenal abscess. The patient further developed incipient diabetic ketoacidosis, disseminated intravascular coagulation, and endogenous endophthalmitis. Occurrence of the latter as a metastatic infection from perirenal abscess caused by this organism is very rare, and we know of no previously reported patient with the additional occurrence of disseminated intravascular coagulation. Since prompt intravitreal antibiotic administration is needed, physicians should be aware of these rare but severe complications of K pneumoniae infection, especially in patients with poorly controlled diabetes.

A novel virulence gene in Klebsiella pneumoniae strains causing primary liver abscess and septic metastatic complications

Primary Klebsiella pneumoniae liver abscess complicated with metastatic meningitis or endophthalmitis is a globally emerging infectious disease. Its pathogenic mechanism remains unclear. The bacterial virulence factors were explored by comparing clinical isolates. Differences in mucoviscosity were observed between strains that caused primary liver abscess (invasive) and those that did not (noninvasive). Hypermucoviscosity correlated with a high serum resistance and was more prevalent in invasive strains (52/53 vs. 9/52; P < 0.0001). Transposon mutagenesis identified candidate virulence genes. A novel 1.2-kb locus, magA, which encoded a 43-kD outer membrane protein, was significantly more prevalent in invasive strains (52/53 vs. 14/52; P < 0.0001). The wild-type strain produced a mucoviscous exopolysaccharide web, actively proliferated in nonimmune human serum, resisted phagocytosis, and caused liver microabscess and meningitis in mice. However, magA⁻ mutants lost the exopolysaccharide web and became extremely serum sensitive, phagocytosis susceptible, and avirulent to mice. Virulence was restored by complementation using a magA-containing plasmid. We conclude that magA fits molecular Koch's postulates as a virulence gene. Thus, this locus can be used as a marker for the rapid diagnosis and for tracing the source of this emerging infectious disease.