Characterization of CRISPR Spacer and Protospacer Sequences in Paenibacillus larvae and Its Bacteriophages.
The bacterium Paenibacillus larvae is the causative agent of American foulbrood, the most devastating bacterial disease of honeybees. Because P. larvae is antibiotic resistant, phages that infect it are currently used as alternative treatments. However, the acquisition by P. larvae of CRISPR spacer sequences from the phages could be an obstacle to treatment efforts. We searched nine complete genomes of P. larvae strains and identified 714 CRISPR spacer sequences, of which 384 are unique. Of the four epidemiologically important P. larvae strains, three of these have fewer than 20 spacers, while one strain has over 150 spacers. Of the 384 unique spacers, 18 are found as protospacers in the genomes of 49 currently sequenced P. larvae phages. One P. larvae strain does not have any protospacers found in phages, while another has eight. Protospacer distribution in the phages is uneven, with two phages having up to four protospacers, while a third of phages have none. Some phages lack protospacers found in closely related phages due to point mutations, indicating a possible escape mechanism. This study serve a point of reference for future studies on the CRISPR-Cas system in P. larvae as well as for comparative studies of other phage-host systems.
['Stamereilers|Casey|C|', 'Wong|Simon|S|', 'Tsourkas|Philippos K|PK|0000-0002-0364-7040']
D000818:Animals D001435:Bacteriophages D001516:Bees D064113:CRISPR-Cas Systems D021901:DNA, Intergenic D016680:Genome, Bacterial D016679:Genome, Viral D000070059:Paenibacillus larvae D039002:Prophages D017422:Sequence Analysis, DNA
CRISPR spacers protospacers Paenibacillus larvae American foulbrood phages bacterial immunity