Dataset Information

Survey of clustered regularly interspaced short palindromic repeats and their associated Cas proteins (CRISPR/Cas) systems in multiple sequenced strains of Klebsiella pneumoniae.

ABSTRACT: In recent years the emergence of multidrug resistant Klebsiella pneumoniae strains has been an increasingly common event. This opportunistic species is one of the five main bacterial pathogens that cause hospital infections worldwide and multidrug resistance has been associated with the presence of high molecular weight plasmids. Plasmids are generally acquired through horizontal transfer and therefore is possible that systems that prevent the entry of foreign genetic material are inactive or absent. One of these systems is CRISPR/Cas. However, little is known regarding the clustered regularly interspaced short palindromic repeats and their associated Cas proteins (CRISPR/Cas) system in K. pneumoniae. The adaptive immune system CRISPR/Cas has been shown to limit the entry of foreign genetic elements into bacterial organisms and in some bacteria it has been shown to be involved in regulation of virulence genes. Thus in this work we used bioinformatics tools to determine the presence or absence of CRISPR/Cas systems in available K. pneumoniae genomes.The complete CRISPR/Cas system was identified in two out of the eight complete K. pneumoniae genomes sequences and in four out of the 44 available draft genomes sequences. The cas genes in these strains comprises eight cas genes similar to those found in Escherichia coli, suggesting they belong to the type I-E group, although their arrangement is slightly different. As for the CRISPR sequences, the average lengths of the direct repeats and spacers were 29 and 33 bp, respectively. BLAST searches demonstrated that 38 of the 116 spacer sequences (33%) are significantly similar to either plasmid, phage or genome sequences, while the remaining 78 sequences (67%) showed no significant similarity to other sequences. The region where the CRISPR/Cas systems were located is the same in all the Klebsiella genomes containing it, it has a syntenic architecture, and is located among genes encoding for proteins likely involved in metabolism and resistance to antibiotics.The CRISPR/Cas system is not widely distributed in K. pneumoniae genomes, those present most likely belong to type I-E with few differences from the arrangement of the cse3 gene and most of the spacers have not been are not described yet. Given that the CRISPR/Cas system is scarcely distributed among K. pneumoniae genomes it is not clear whether it is involved in either immunity against foreign genetic material or virulence. We consider that this study represents a first step to understand the role of CRISPR/Cas in K. pneumoniae.

SUBMITTER: Ostria-Hernandez ML

PROVIDER: S-EPMC4522967 | biostudies-literature | 2015

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Survey of clustered regularly interspaced short palindromic repeats and their associated Cas proteins (CRISPR/Cas) systems in multiple sequenced strains of Klebsiella pneumoniae.

Ostria-Hernández Martha Lorena ML Sánchez-Vallejo Carlos Javier CJ Ibarra J Antonio JA Castro-Escarpulli Graciela G

BMC research notes 20150804

<h4>Background</h4>In recent years the emergence of multidrug resistant Klebsiella pneumoniae strains has been an increasingly common event. This opportunistic species is one of the five main bacterial pathogens that cause hospital infections worldwide and multidrug resistance has been associated with the presence of high molecular weight plasmids. Plasmids are generally acquired through horizontal transfer and therefore is possible that systems that prevent the entry of foreign genetic material ...[more]

PMID: 26238567

Similar Datasets

Project description:BackgroundCampylobacter jejuni is the leading bacterial pathogen that causes foodborne illness worldwide. Because of genetic diversity and sophisticated growth requirements of C. jejuni, several genotyping methods have been investigated to classify this bacterium during the outbreaks. One of such method is to use clustered regularly interspaced short palindromic repeats (CRISPR).ObjectivesThe goal of this study was to explore the diversity of C. jejuni isolates with CRISPR from an animal farm.MethodsSeventy-seven C. jejuni isolates from an animal farm were used in this study. The day-old broilers were reared with other poultry and farm animals, including layer hens, guinea hens, dairy goats and sheep. A small swine herd was also present on an adjacent, but separate plot of land. Isolation and identification of C. jejuni were performed according to the standard procedures. The CRISPR type 1 was PCR amplified from genomic DNA, and the amplicons were sequenced by the Sanger dideoxy method. The direct repeats (DRs) and spacers of the CRISPR sequences were identified using the CRISPRFinder.ResultsThe CRISPR sequences were detected in all 77 isolates. One type of DRs was identified in these 77 isolates. The lengths of the CRISPR locus ranged from 100 to 560 nucleotides, whereas the number of spacers ranged from one to eight. The distributions of the numbers of CRISPR spacers from different sources seemed to be random. Overall, 17 out of 77 (22%) C. jejuni isolates had two and five spacers, whereas 14 out of 77 (18%) isolates had three spaces in their genomes. By further analysis of spacer sequences, a total of 266 spacer sequences were identified in 77 C. jejuni isolates. By comparison with known published spacer sequences, we observed that 49 sequences were unique in this study. The CRISPR sequence combination of Nos. 16, 19, 48 and 57 was found among a total of 15 C. jejuni isolates containing various multi-locus sequence typing (MLST) types (ST-50, ST-607, ST-2231 and ST-5602). No. 57 spacer sequence was unique from this study, whereas the other three (Nos. 16, 19 and 48) sequences were found in previous reports. Combination of Nos. 5, 9, 15, 30 and 45 was associated with ST-353. To compare the CRISPR genotyping with other methods, the MLST was selected due to its high discriminatory power to differentiate isolates. Based on calculation of the Simpson's index of diversity, a combination of both methods had higher Simpson's index value than those for CRISPR or MLST, respectively.ConclusionsOur results suggest that the MLST from C. jejuni isolates can be discriminated based on the CRISPR unique spacer sequences and the numbers of spacers. In the future, investigation on the CRISPR resolution for C. jejuni identification in outbreaks is needed. A database that integrates both MLST sequences and CRISPR sequences and is searchable is greatly in demand for tracking outbreaks and evolution of this bacterium.

Dataset Information

Survey of clustered regularly interspaced short palindromic repeats and their associated Cas proteins (CRISPR/Cas) systems in multiple sequenced strains of Klebsiella pneumoniae.

Publications

Survey of clustered regularly interspaced short palindromic repeats and their associated Cas proteins (CRISPR/Cas) systems in multiple sequenced strains of Klebsiella pneumoniae.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets