Role of dihydroxyacetone kinases I and II in the dha regulon of Klebsiella pneumoniae

ABSTRACT The airway epithelium represents a primary site for contact between microbes and their hosts. To assess the role of complement in this event, we studied the interaction between the A549 cell line derived from human alveolar epithelial cells and a major nosocomial pathogen, Klebsiella pneumoniae, in the presence of serum. In vitro, we found that C3 opsonization of poorly encapsulated K. pneumoniae clinical isolates and an unencapsulated mutant enhanced dramatically bacterial internalization by A549 epithelial cells compared to highly encapsulated clinical isolates. Local complement components (either present in the human bronchoalveolar lavage or produced by A549 epithelial cells) were sufficient to opsonize K. pneumoniae. CD46 could competitively inhibit the internalization of K. pneumoniae by the epithelial cells, suggesting that CD46 is a receptor for the binding of complement-opsonized K. pneumoniae to these cells. We observed that poorly encapsulated strains appeared into the alveolar epithelial cells in vivo but that (by contrast) they were completely avirulent in a mouse model of pneumonia compared to the highly encapsulated strains. Our results show that bacterial opsonization by complement enhances the internalization of the avirulent microorganisms by nonphagocytic cells such as A549 epithelial cells and allows an efficient innate defense.

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Role of the nifQ gene product in the incorporation of molybdenum into nitrogenase in Klebsiella pneumoniae.

Journal of Bacteriology ◽

10.1128/jb.158.1.187-194.1984 ◽

1984 ◽

Vol 158 (1) ◽

pp. 187-194 ◽

Cited By ~ 81

Author(s):

J Imperial ◽

R A Ugalde ◽

V K Shah ◽

W J Brill

Keyword(s):

Klebsiella Pneumoniae ◽

Gene Product

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Hemophagocytic Lymphohistiocytosis Associated to Klebsiella pneumoniae Infection: A Case Report

Frontiers in Immunology ◽

10.3389/fimmu.2021.684805 ◽

2021 ◽

Vol 12 ◽

Author(s):

Zhiyu Zhang ◽

Junqian Liu ◽

Jinggyue Wang ◽

Yushi Wang

Keyword(s):

Case Report ◽

Klebsiella Pneumoniae ◽

Hemophagocytic Lymphohistiocytosis ◽

Klebsiella Pneumonia ◽

Initial Condition ◽

Organ Function ◽

Cardiac Intensive Care Unit ◽

Function Impairment ◽

Cardiac Intensive Care

This is a case analysis of a 73-year-old Chinese man admitted to the cardiac intensive care unit (ICU) with fever and general pain. Based on the patient’s initial condition of multi-organ function impairment and increased serum ferritin, and after a series of examinations, the patient was diagnosed with Klebsiella pneumonia-induced hemophagocytic lymphohistiocytosis (HLH). Meropenem and dexamethasone were used in combination to treat the patient, and the results were very successful. In this case report, it is further suggested that Klebsiella pneumoniae is a possible trigger of HLH, and a combination of antibiotics and corticosteroids can be effective in treating HLH. It is also recommended that doctors in the ICU of each department should pay attention to the role of hyperferritinemia in the diagnosis of HLH, and ICU admission teams should include ferritin in their monitoring.

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