Pyrosequencing-based analysis reveals a novel capsular gene cluster in a KPC-producing Klebsiella pneumoniae clinical isolate identified in Brazil

Pyrosequencing-based analysis reveals a novel capsular gene cluster in a KPC-producing Klebsiella pneumoniae clinical isolate identified in Brazil

Author Pereira Ramos, Pablo Ivan Google Scholar
Picão, Renata Cristina Autor UNIFESP Google Scholar
Vespero, Eliana Carolina Google Scholar
Pelisson, Marsileni Google Scholar
Goda Zuleta, Luiz Fernando Google Scholar
Almeida, Luiz Gonzaga P. Google Scholar
Gerber, Alexandra L. Google Scholar
Vasconcelos, Ana Tereza R. Google Scholar
Gales, Ana Cristina Autor UNIFESP Google Scholar
Nicolas, Marisa Fabiana Google Scholar
Institution LNCC
Universidade Federal do Rio de Janeiro (UFRJ)
Universidade Estadual de Londrina (UEL)
Universidade Federal de São Paulo (UNIFESP)
Abstract Background: An important virulence factor of Klebsiella pneumoniae is the production of capsular polysaccharide (CPS), a thick mucus layer that allows for evasion of the host's defense and creates a barrier against antibacterial peptides. CPS production is driven mostly by the expression of genes located in a locus called cps, and the resulting structure is used to distinguish between different serotypes (K types). in this study, we report the unique genetic organization of the cps cluster from K. pneumoniae Kp13, a clinical isolate recovered during a large outbreak of nosocomial infections that occurred in a Brazilian teaching hospital.Results: A pyrosequencing-based approach showed that the cps region of Kp13 (cps(Kp13)) is 26.4 kbp in length and contains genes common, although not universal, to other strains, such as the rm/BADC operon that codes for L-rhamnose synthesis. cpsKp13 also presents some unique features, like the inversion of the wzy gene and a unique repertoire of glycosyltransferases. in silico comparison of cps(Kp13) RFLP pattern with 102 previously published cps PCR-RFLP patterns showed that cpsKp13 is distinct from the C patterns of all other K serotypes. Furthermore, in vitro serotyping showed only a weak reaction with capsular types K9 and K34. We confirm that K9 cps shares common genes with cps(Kp13) such as the rm/BADC operon, but lacks features like uge and Kp13-specific glycosyltransferases, while K34 capsules contain three of the five sugars that potentially form the Kp13 CPS.Conclusions: We report the first description of a cps cluster from a Brazilian clinical isolate of a KPC-producing K. pneumoniae. the gathered data including K-serotyping support that Kp13's K-antigen belongs to a novel capsular serotype. the CPS of Kp13 probably includes L-rhamnose and D-galacturonate in its structure, among other residues. Because genes involved in L-rhamnose biosynthesis are absent in humans, this pathway may represent potential targets for the development of antimicrobial agents. Studying the capsular serotypes of clinical isolates is of great importance for further development of vaccines and/or novel therapeutic agents. the distribution of K-types among multidrug-resistant isolates is unknown, but our findings may encourage scientists to perform K-antigen typing of KPC-producing strains worldwide.
Keywords Capsular gene cluster
Capsular polysaccharide
KPC-producing K. pneumoniae
Molecular serotyping
Monosaccharide biosynthesis pathways
Language English
Date 2012-08-11
Published in Bmc Microbiology. London: Biomed Central Ltd, v. 12, 12 p., 2012.
ISSN 1471-2180 (Sherpa/Romeo, impact factor)
Publisher Biomed Central Ltd
Extent 12
Access rights Open access Open Access
Type Article
Web of Science ID WOS:000308565400001

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