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Category: Clinical Microbiology
The Emerging Role of Klebsiellae in Liver Abscess, Page 1 of 2
< Previous page | Next page > /docserver/preview/fulltext/10.1128/9781555815585/9781555813772_Chap11-1.gif /docserver/preview/fulltext/10.1128/9781555815585/9781555813772_Chap11-2.gifAbstract:
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.
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Changing epidemiology of pyogenic liver abscess in Taiwan. The graph shows the percentage of K. pneumoniae among pyogenic liver abscesses in Taiwan.
Pathogen-specific incidence of adult community-acquired bacterial meningitis diagnosed at National Taiwan University Hospital during the periods from 1993 to 1994, 1995 to 1996, and 1997 to 1998.
(A and B) Histopathology in the liver and brain of a mouse inoculated with 105 CFU of K. pneumoniae NTUH-K2044, examined on day 9 after inoculation (hematoxylin and eosin stain; magnification, ×100 [A] versus ×200 [B]). (C and D) Histopathology in the liver and brain of a mouse inoculated with 105 CFU of K. pneumoniae magA mutant, examined on day 9 after inoculation (hematoxylin and eosin stain; magnification, ×100). Panels A and B show severe meningitis and liver microabscess; panels C and D show normal histology.
Sequences of the magA flanking region revealed a 33-kb fragment, which was replaced with a 28-kb fragment in MGH78578.
Histological examination of the livers and brains of mice. K. pneumoniae was given to mice by intragastric inoculation at a dose of 104 CFU. (A and B) Mice inoculated with NTUH-K2044. (C and D) Mice inoculated with MGH 78578. (A) Severe liver abscess (hematoxylin and eosin stain; magnification, ×40). (B) Meningitis and brain abscess (hematoxylin and eosin stain; magnification, ×100). (C and D) Normal histology (hematoxylin and eosin stain; magnification, ×100).
Characteristics of PLA studies