| Summary: | Hypermucoviscosity phenotypic <i>Klebsiella pneumoniae</i> (HV-<i>Kp</i>) serotype K1 is the predominant pathogen of a pyogenic liver abscess, an emerging infectious disease that often complicates septic metastatic syndrome in diabetic patients with poor sugar control. HV-<i>Kp</i>isolates were more resistant to neutrophil phagocytosis than non-HV-<i>Kp</i>isolates because of different pathogen-associated molecular patterns. The protein expression of HV-<i>Kp</i> after interaction with neutrophils is unclear. We studied KP-M1 (HV phenotype; serotype K<sub>1</sub>), DT-X (an acapsularmutant strain of KP-M1), and <i>E. coli</i> (ATCC 25922) with the model of <i>Kp-</i>infected neutrophils, using a comparative proteomic approach. One the identified protein, namely fructose-1, 6-bisphosphate aldolase (FBA), was found to be distributed in the KP-M1 after infecting neutrophils. Cell fractionation experiments showed that FBA is localized both to the cytoplasm and the outer membrane. Flow cytometry demonstrated that outer membrane-localized FBA was surface-accessible to FBA-specific antibody. The <i>fba</i> gene expression was enhanced in high glucose concentrations, which leads to increasing bacterial resistance to neutrophils phagocytosis and killing. The KP-M1 after FBA inhibitors and FBA-specific antibody treatment showed a significant reduction in bacterial resistance to neutrophils phagocytosis and killing, respectively, compared to KP-M1 without treatment. FBA is a highly conserved surface-exposed protein that is required for optimal interaction of HV-<i>Kp</i> to neutrophils.
|
|---|