|Awad, Amal - Mansoura University|
Submitted to: Meeting Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 5/3/2019
Publication Date: N/A
Interpretive Summary: none
Technical Abstract: Problem Statement: Campylobacter jejuni is the leading pathogen that causes human acute gastrointestinal illness worldwide. Due to their genetic diversity, fastidious growth and sophisticated biochemical requirements, classification of Campylobacter by traditional techniques is problematic. Several typing methods based on molecular techniques have been explored to determine the diversity of this bacterium. One such method is to use clustered regularly interspaced short palindromic repeats (CRISPR), short sequence repeats consisting of direct repeats interspaced with nonrepetitive spacers. In this study, we applied this typing method to explore the genetic diversity of Campylobacter jejuni isolated from poultry sources. Approach: A total of 99 Campylobacter jejuni isolates from poultry and its surrounding environments in four different states of U.S.A. Genomic DNA of C. jejuni isolates were extracted from cultures grown in Müeller-Hinton agar at 42 oC for 48 hr using a commercial kit. PCR primers and conditions for CRISPR type 1 amplification were described previously. The amplicons were purified with a commercial kit, and the purified DNA fragments were sent to the USDA ARS Genomics and Bioinformatics Research Unit for sequencing, where the Sanger dideoxy sequencing method was performed. The direct repeats (DR) and spacers of the CRISPR sequences were identified using the CRISPRFinder. Results: According to the CRISPRFinder, the results show there were 21 (21%) isolates no detectable, 29 (30%) isolates questionable and 49 (49%) isolates confirmed CRISPR. The lengths of CRISPR range from 100 to 695 base pairs. One type of DR was found in CRISPR of these isolates. The number of spacers in CRISPR ranges from one to 10 with various sequences. Conclusions: The results of our study show the CRISPR typing on Campylobacter jejuni may be complementary to the other genotyping methods.