Vibrio cholerae -specific bacteriophages are common features of the microbial community during cholera infection in humans. Phages impose strong selective pressure that favors the expansion of phage-resistant strains over their vulnerable counterparts. The mechanisms allowing virulent V . cholerae strains to defend against the ubiquitous threat of predatory phages have not been established. Here, we show that V . cholerae PLEs ( p hage-inducible chromosomal island- l ike e lements) are widespread genomic islands dedicated to phage defense. Analysis of V . cholerae isolates spanning a 60-year collection period identified five unique PLEs. Remarkably, we found that all PLEs (regardless of geographic or temporal origin) respond to infection by a myovirus called ICP1, the most prominent V . cholerae phage found in cholera patient stool samples from Bangladesh. We found that PLE activity reduces phage genome replication and accelerates cell lysis following ICP1 infection, killing infected host cells and preventing the production of progeny phage. PLEs are mobilized by ICP1 infection and can spread to neighboring cells such that protection from phage predation can be horizontally acquired. Our results reveal that PLEs are a persistent feature of the V . cholerae mobilome that are adapted to providing protection from a single predatory phage and advance our understanding of how phages influence pathogen evolution. Author summary Vibrio cholerae is the causative agent of the severe diarrheal disease cholera. V . cholerae is commonly recovered from patient samples with predatory bacteriophages (phages), which impose strong selective pressure favoring phage resistant strains over their vulnerable counterparts. Here, we investigated the activity of PLEs ( p hage-inducible chromosomal island- l ike e lements), a novel group of mobile genetic elements that have contributed to phage resistance in V . cholerae over the last 60 years. Surprisingly, we found that PLEs are protective against a single, prevalent phage type. We found that PLE activity reduces phage genome replication and accelerates the kinetics of bacterial cell lysis. Our study shows that mobile genetic elements play a key role in phage resistance in successful epidemic V . cholerae .
【초록키워드】 Evolution, Genetic, Infection, Stool, Kinetics, Epidemic, pathogen, humans, Patient, bacteriophage, expansion, genomic, microbial community, mechanism, Protective, strain, bacteriophages, Vibrio cholerae, phage genome, bacterial cell, host cells, host cell, causative agent, diarrheal disease, favor, selective, genome replication, Defense, phage, element, phages, cholerae, neighboring cells, progeny, cell lysis, virulent, diarrheal, killing, isolate, widespread, FIVE, feature, prevalent, spread to, investigated, unique, contributed, chromosomal, reduce, respond, accelerate, defend, disease cholera, neighboring cell, phage-resistant, predatory, 【제목키워드】 Vibrio cholerae, Defense, conserved,