Genetically similar isolates of Klebsiella pneumoniae serotype K1 causing liver abscesses in three continents

Abstract

ThemagAgene was sought in hypermucoviscous isolates ofKlebsiellaspp., theKlebsiellaK serotype reference strains and in isolates of the K1 serotype ofKlebsiella pneumoniaefrom the UK, Hong Kong, Israel, Taiwan and Australia. Only K1 isolates were PCR positive formagA; this gene was found in all such isolates tested. Hypermucoviscosity was not confined tomagApositive isolates, nor was it found in allmagApositive isolates. Comparison ofXbaI PFGE profiles revealed that most (19/23) of themagApositive isolates clustered within 72 % similarity, with a further subcluster of isolates, from three different continents, clustering within >80 %. All of the 16 isolates tested within the main cluster had the same sequence type (ST 23) by multilocus sequence typing, with the exception of one isolate, which had a single nucleotide difference at one of the seven loci. This study indicates that a genotype strongly associated with highly invasive disease in Taiwan, where large numbers of cases have been reported, is geographically very widespread.