CRISPR Content Correlates with the Pathogenic Potential of Escherichia coli
نویسندگان
چکیده
Guide RNA molecules (crRNA) produced from clustered regularly interspaced short palindromic repeat (CRISPR) arrays, altogether with effector proteins (Cas) encoded by cognate cas (CRISPR associated) genes, mount an interference mechanism (CRISPR-Cas) that limits acquisition of foreign DNA in Bacteria and Archaea. The specificity of this action is provided by the repeat intervening spacer carried in the crRNA, which upon hybridization with complementary sequences enables their degradation by a Cas endonuclease. Moreover, CRISPR arrays are dynamic landscapes that may gain new spacers from infecting elements or lose them for example during genome replication. Thus, the spacer content of a strain determines the diversity of sequences that can be targeted by the corresponding CRISPR-Cas system reflecting its functionality. Most Escherichia coli strains possess either type I-E or I-F CRISPR-Cas systems. To evaluate their impact on the pathogenicity of the species, we inferred the pathotype and pathogenic potential of 126 strains of this and other closely related species and analyzed their repeat content. Our results revealed a negative correlation between the number of I-E CRISPR units in this system and the presence of pathogenicity traits: the median number of repeats was 2.5-fold higher for commensal isolates (with 29.5 units, range 0-53) than for pathogenic ones (12.0, range 0-42). Moreover, the higher the number of virulence factors within a strain, the lower the repeat content. Additionally, pathogenic strains of distinct ecological niches (i.e., intestinal or extraintestinal) differ in repeat counts. Altogether, these findings support an evolutionary connection between CRISPR and pathogenicity in E. coli.
منابع مشابه
A study on the presence of some potential virulence genes and quinolone resistance in avian pathogenic Escherichia coli isolated from chickens in Northeast of Iran
Background: Avian pathogenic Escherichia coli (APEC), which is the causative agent of colibacillosis, harbors several putative virulence genes. An important trait of APEC for both poultry and public health is antibiotic resistance. Objectives: In the present study, some potential virulence genes of APECs isolated from Northeast of Iran and their resistance to the quinolones antibiotics were stu...
متن کاملExtra intestinal pathogenic Escherichia coli from human and avian origin: Detection of the most common virulence-encoding genes
Pathogenic Escherichia coli strains cause a wide range of extra intestinal infections including urinary tract infection in humans and colibacillosis in poultry. They are classified into uropathogenic E. coli (UPEC) and avian pathogenic E. coli (APEC) with genetic similarities and variations. Their pathogenicity is related to the virulence-encoding genes like sfa</...
متن کاملDetection of eaeA, hlyA, stx1 and stx2 genes in pathogenic Escherichia coli isolated from broilers affected with colibacillosis
Background: Foodborne outbreaks associated with shiga toxin-producing Escherichia coli (STEC) have been well documented worldwide. STECs are major causative agents of gastroenteritis in humans that may be complicated by hemorrhagic colitis (HC), hemolytic uremic syndrome (HUS), and thrombotic thrombocytopenia purpura (TTP). OBJECTIVES: The aim of this study was to investigate the presence of vi...
متن کاملIsolation of lytic bacteriophages against pathogenic Escherichia coli strains in poultry in the northwest of Iran
In this study, 90 internal organ samples of poultry with symptoms of colibacillosis were obtained from Maragheh poultry farms in East Azerbaijan, Iran. In total, 70 bacterial isolates were confirmed as Escherichia coli (E. coli) strains using standard biochemical tests, and antibiotic sensitivity was determined by the disk diffusion method. Antibiotics used in this study included ampicillin, pe...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره 10 شماره
صفحات -
تاریخ انتشار 2015