Insertion sequences in the CRISPR-Cas system regulate horizontal antimicrobial resistance gene transfer in Shigella strains.

Multidrug-resistant (MDR) Shigella strains are an enormous threat to public health. Antimicrobial resistance genes are frequently located on plasmids, phages and integrons, which enter bacterial cells by horizontal gene transfer (HGT). CRISPR-Cas systems are adaptive prokaryotic immune systems in bacteria that confer resistance to foreign genetic material such as phages and other mobile genetic elements.

Bioinformatics analyses of Shigella CRISPR structure and spacer classification.

Clustered regularly interspaced short palindromic repeats (CRISPR) are inheritable genetic elements of a variety of archaea and bacteria and indicative of the bacterial ecological adaptation, conferring acquired immunity against invading foreign nucleic acids. Shigella is an important pathogen for anthroponosis. This study aimed to analyze the features of Shigella CRISPR structure and classify the spacers through bioinformatics approach.

[Molecular characteristics of Clustered Regularly Interspaced Short Palindromic Repeat in Shigella].

Objective: To detect the molecular characteristics of Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR) in Shigella and to analyze the distribution of CRISPR related to the time of isolation.

Methods: Of the 52 Shigella strains, 41 were isolated from Henan, 6 from Jiangxi and 5 isolated from Beijing. Both CRISPR locus of S1, S2, S3 and S4 in Shigella were detected by polymerase chain reaction (PCR).

[Detection of CRISPR and its relationship to drug resistance in Shigella].

Objective: To detect clustered regularly interspaced short palindromic repeats (CRISPR) in Shigella, and to analyze its relationship to drug resistance.

Methods: Four pairs of primers were used for the detection of convincing CRISPR structures CRISPR-S2 and CRISPR-S4, questionable CRISPR structures CRISPR-S1 and CRISPR-S3 in 60 Shigella strains. All primers were designed using sequences in CRISPR database.

[Bioinformatics Analysis of Clustered Regularly Interspaced Short Palindromic Repeats in the Genomes of Shigella].

This study was aimed to explore the features of clustered regularly interspaced short palindromic repeats (CRISPR) structures in Shigella by using bioinformatics. We used bioinformatics methods, including BLAST, alignment and RNA structure prediction, to analyze the CRISPR structures of Shigella genomes. The results showed that the CRISPRs existed in the four groups of Shigella, and the flanking sequences of upstream CRISPRs could be classified into the same group with those of the downstream.

Detection and analysis of CRISPRs of Shigella.

The recently discovered CRISPRs (Clustered regularly interspaced short palindromic repeats) and Cas (CRISPR-associated) proteins are a novel genetic barrier that limits horizontal gene transfer in prokaryotes and the CRISPR loci provide a historical view of the exposure of prokaryotes to a variety of foreign genetic elements. The aim of study was to investigate the occurrence and distribution of the CRISPRs in Shigella. A collection of 61 strains of Shigella were screened for the existence of CRISPRs.

[Clustered regularly interspaced short palindromic repeat associated protein genes cas1 and cas2 in Shigella].

Objective: To detect the distribution of clustered regularly interspaced short palindromic repeat (CRISPR) associated protein genes cas1 and cas2 in Shigella and to understand the characteristics of CRISPR with relationship between CRISPR and related characteristics on drug resistance.

Methods: CRISPR associated protein genes cas1 and cas2 in Shigella were detected by PCR, with its products sequenced and compared.

Results: The CRISPR-associated protein genes cas1 and cas2 were found in all the 196 Shigella isolates which were isolated at different times and locations in China.