Clinical implications of hypermucoviscosity phenotype in Klebsiella pneumoniae isolates: association with invasive syndrome in patients with community‐acquired bacteraemia

. Background. Klebsiella pneumoniae, a Gram‐negative bacillus usually forming glistening mucoid colonies with viscid consistency on the culture plate, is a common pathogen causing various clinical infection patterns. However, little is known about the clinical implications of this mucoid character. Objective. The purposes of this study, therefore, were to investigate the frequency of hypermucoviscosity (HV) in bacteraemic isolates of K. pneumoniae, and determine the significance of any association between HV and various clinical manifestations. Design. Retrospective observational study. Patients. Patients diagnosed with K. pneumoniae bacteraemia at a community‐based university hospital between June 1999 and June 2001 were enrolled in this analysis. Measurements. Clinical data concerning comorbid diseases and infection patterns was collected. K. pneumoniae bacteraemic isolates were examined for the presence of HV using a modified string test. The clinical impact of HV and risk factors for the invasive syndrome were assessed using statistical analysis. Polymerase chain reaction (PCR) was performed to detect magA, a gene related to HV phenotype. Results. Overall, 200 (64.9%) of the 308 cases of K. pneumoniae bacteraemia were community‐acquired infections. Compared with hospital‐acquired K. pneumoniae bacteraemia (HA‐KpB), community‐acquired K. pneumoniae bacteraemia (CA‐KpB) was more likely to be monomicrobial in nature (83.5% vs. 64.8%; P