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High prevalence of phagocytic-resistant capsular serotypes of Klebsiella pneumoniae in liver abscess

Abstract number: 903_r2097

Li-Yueh H.

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Objectives:

To assess the role of K. pneumoniae CPS K1 or K2 in liver abscess and development of endophthalmitis, we used an experimental model of phagocytosis for K. pneumoniae with different CPS isolated from patients with and without liver abscess and compared the resistance of the isolates to neutrophil-mediated phagocytosis.

Methods:

Neutrophil phagocytosis of 70 CPS isolates included K1 (n = 23)/K2 (n = 10), non-K1/K2 (n = 37) were evaluated by flow cytometry, fluorescence imaging, and electron microscopy.

Results:

K1/K2 isolates were significantly more resistant to phagocytosis (P < 0.0001) than non-K1/K2 isolates, and displayed increased resistance to intracellular killing. Although mucoid phenotype (M-type) K1/K2 isolates were significantly resistant to phagocytosis (P = 0.0029) than M-type non-K1/K2, no significant difference in the phagocytosis rate was observed between K1/K2 isolates with M-type and non-M-type (P = 0.0924). Mucoidy is an associated factor that was predominant in K1/K2 isolates, but which itself is not an independent influence to phagocytic resistance. The K1/K2 CPS proved significantly more resistant to phagocytosis than non-K1/K2 CPS in liver abscess isolates (P < 0.0001) and nonabscess isolates (P = 0.0001), implicating K1/K2 isolates were generally more virulent in both liver abscess and in nonliver abscess conditions.

Conclusions:

Resistance of CPS K1 or K2 K. pneumoniae to phagocytosis and intracellular killing may thus contribute to their high prevalence in liver abscess and uniquely in endophthalmitis.

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Session Details

Date: 01/08/2007
Time: 00:00-00:00
Session name: XXIst ISTH Congress
Subject:
Location: Oxford, UK
Presentation type:
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