Genomic Analysis and Structural Elucidation of the Capsular Polysaccharide Structure Produced by Carbapenem Resistant Klebsiella Pneumoniae Kk207-2

Session: 
PS2 Poster session 2 Even numbers
Code: 
P34
Location (hall): 
Foyer
Start/end time: 
Tuesday, July 2, 2019 - 15:45 to 17:15
Paola
Cescutti

Barbara Bellich1, Neil Ravenscroft2, Cristina Lagatolla1, Marco Maria D’Andrea3, Gian Maria Rossolini4, Paola Cescutti1

1Dept. of Life Sciences, University of Trieste, Trieste, Italy, 2Dept of Chemistry, University of Cape Town, Cape Town, South Africa, 3Dept. of Medical Biotechnologies, University of Siena, Siena, Italy, 4Dept. of Experimental and Clinical Medicine, University of Florence and Microbiology and Virology Unit, Florence Careggi University Hospital, Florence, Italy

Klebsiella pneumoniae is mostly responsible for nosocomial infections in immunocompromised patients, but can also cause severe community-acquired infections. The clinical scenario has worsened in recent years, with the global emergence and dissemination of K. pneumoniae strains resistant to carbapenems (CR-Kp). The major carbapenem resistance mechanism among CR-Kp is the production of carbapenemase, i.e. KPC. The most successful and widespread disseminated clonal group (CG) of KPC-producing K. pneumoniae (KPC-Kp) is CG258, which can be further differentiated in two clades characterized by the production of distinct capsular polysaccharides. Infections caused by KPC-Kp strains are challenging in healthcare settings, where they spread rapidly and are associated with significant morbidity and mortality [1].

Genotyping of the cps207-2 gene cluster with the wzc-based method showed that it is a new K-type, while the wzi-based method associated it to the already known K41 K-type.

Therefore, the primary structure of the capsular polysaccharide produced by K. pneumoniae KK207-2 [2], a member of the clade I of CG258, was determined by using GLC-MS of appropriate carbohydrate derivatives, ESI-MS of both partial hydrolysis and Smith degradation derived oligosaccharides, and NMR spectroscopy of oligosaccharides, lithium degraded CPS, and the native and de-O-acetylated CPS. The results showed that the repeating unit of KK207-2 capsular polysaccharide (Fig. 1a) is a novel one among the Klebsiella K-types. Moreover, each glycosyltransferase in the sequenced cps207-2 gene cluster was assigned to the corresponding catalyzed reaction (Fig. 1b, 1c).

Figure 1: (a) Structure of the capsular polysaccharide repeating unit of Klebsiella pneumoniae KK207-2. (b) Glycosyltransferases of the Klebsiella pneumoniae KK207-2 cps gene cluster are listed above the respective glycosidic linkage. The polymerization site is marked by an arrow. (c) Identification of genes coded in the central region of the cps207-2 cluster.

References: 
  1. Lee, C-R.; Lee, J. H.; Park, K. S.; Kim, Y. B.; Jeong, B. C.; Lee, S. H. Global dissemination of carbapenemase-producing Klebsiella pneumoniae: epidemiology, genetic context, treatment options, and detection methods. Front. Microbiol. [Online], 2016, 7, 895. https://doi.org/10.3389/fmicb.2016.00895.
  2. [2]        D’Andrea, M. M.; Amisano, F.; Giani, T.; Conte, V.; Ciacci, N.; Ambretti, S.; Santoriello, L.; Rossolini, G. M. Diversity of capsular polysaccharide gene clusters in Kpc-producing Klebsiella pneumoniae clinical isolates of sequence type 258 involved in the Italian epidemic. PLoS ONE [Online] 2014, 9(5) e96827. https://doi.org/10.1371/journal.pone.0096827.
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