Genetic analysis of capsular polysaccharide synthesis gene clusters in 79 capsular types of Klebsiella spp

Abstract

A total of 79 capsular types have been reported in Klebsiella spp., whereas capsular polysaccharide synthesis (cps) regions were available in only 22 types. Due to the limitations of serotyping, complete repertoire of cps will be helpful for capsular genotyping. We therefore resolved the rest 57 cps and conducted comparative analysis. Clustering results of 1,515 predicted proteins from cps loci categorized proteins which share similarity into homology groups (HGs) revealing that 77 Wzy polymerases were classified into 56 HGs, which indicate the high specificity of wzy between different types. Accordingly, wzy-based capsular genotyping could differentiate capsule types except for those lacking wzy (K29 and K50), those sharing identical wzy (K22 vs. K37); and should be carefully applied in those exhibited high similarity (K12 vs. K41, K2 vs. K13, K74 vs. K80, K79 vs. KN1 and K30 vs. K69). Comparison of CPS structures in several capsular types that shared similarity in their gene contents implies possible functions of glycosyltransferases. Therefore, our results provide complete set of cps in various types of Klebsiella spp., which enable the understandings of relationship between genes and CPS structures and are useful for identification of documented or new capsular types.

Identification ofKlebsiellacapsule synthesis loci from whole genome data

“…Klocus nucleotide sequences for each of the 77 K-type references and 2 serologically non-typeable strains published elsewhere (Arakawa et al, 1995;Chuang et al, 2006;Fevre et al, 2011;Pan et al, 2008Pan et al, , 2015Shu et al, 2009) were obtained from GenBank or directly from the authors (accession numbers are shown in Table S2). A total of 12 additional K-locus sequences had been published prior to the K-type references The et al, 2015;Wyres et al, 2015); we have compared these loci to those of the 77 K-type references (Arakawa et al, 1995;Chuang et al, 2006;Fevre et al, 2011;Pan et al, 2008Pan et al, , 2015Shu et al, 2009) and identified 7 that were novel. These 7 novel loci plus 17 distinct loci described in our recent survey (Follador et al, 2016) were added to the non-redundant list of K-locus reference sequences, resulting in a total of 103 loci (see Table S2).…”

“…K-locus nucleotide sequences and annotations are now available for a large number of Kp isolates, including the 77 K-type reference strains (Chuang et al, 2006;Follador et al, 2016;Pan et al, 2008Pan et al, , 2015Shu et al, 2009;The et al, 2015;Wyres et al, 2015). Serological Ktypes are generally defined by distinct sets of protein-encoding genes in the variable central region of the K-locus; however, two types (K22 and K37) are distinguished by a point mutation resulting in a premature stop codon that affects acetyltransferase function (Pan et al, 2015).…”

“…Serological Ktypes are generally defined by distinct sets of protein-encoding genes in the variable central region of the K-locus; however, two types (K22 and K37) are distinguished by a point mutation resulting in a premature stop codon that affects acetyltransferase function (Pan et al, 2015).…”

“…Kp employ a Wzy-dependent capsule synthesis process (Rahn et al, 1999;Whitfield, 2006) for which the associated genes are in the capsule synthesis locus (K-locus), which is 10-30 kbp in length (Arakawa et al, 1995;Chuang et al, 2006;Fevre et al, 2011;Pan et al, 2008Pan et al, , 2015Shu et al, 2009). The K-locus includes a set of common genes in the terminal regions that encode the core capsule biosynthesis machinery (e.g.…”

Development of a Colloidal Gold-Based Immunochromatographic Strip for Rapid Detection of Klebsiella pneumoniae Serotypes K1 and K2

“…There are 77 different serotypes of the capsular polysaccharides (CPSs) of K. pneumoniae (2), with K2 and K21 being the most prevalent in western countries (3). Recently, by genotyping capsular polysaccharide genes, 79 capsular types were distinguished (4,5). In contrast, the K1 and K2 serotypes are most often associated with bacteremia, liver abscess, and community-acquired pneumonia in Asia (3).…”