The Emerging Role of Klebsiellae in Liver Abscess

Abstract

The majority of organisms involved in pyogenic liver abscess (PLA) originate from the gastrointestinal tract. The study by Huang et al. suggested that Klebsiella was becoming a more common pathogen in cases of PLA. Also of interest was the fact that in the majority of cases in which Klebsiella was recovered, it was the only pathogen. Therefore, the percentage of PLA cases caused by Klebsiella alone was substantially greater in this study than in any prior study from the United States. However, in recent years, bacterial virulence has been found to play an important role in the pathogenesis of the disease. A multinational prospective study revealed a global difference in clinical patterns of community-acquired Klebsiella pneumoniae bacteremia, with a distinctive form of K. pneumoniae infection causing liver abscess, endophthalmitis, and meningitis almost exclusively in Taiwan. The most common signs and symptoms of PLA are fever, right upper quadrant pain, and chills. The most common laboratory abnormalities are a low albumin level, elevated alkaline phosphatase, and an elevated white blood cell count. The majority of patients have lesions in the right lobe of the liver. While cases of pyogenic liver abscesses have been reported in the literature for many years, there have been many changes in the epidemiology of the disease. Recently, virulence factors, such as that encoded by the magA gene, have been identified. Strains with magA are also strongly associated with metastatic complications, such as endophthalmitis and meningitis.