Moderate-Throughput Identification and Comparison of Campylobacter-Infecting Bacteriophages

Abstract

AbstractCampylobacter jejuniis a leading cause of foodborne infection due to its ability to asymptomatically colonize agricultural animals. In addition to its prevalence,Campylobacteris becoming increasingly resistant to the clinical antibiotics, azithromycin and ciprofloxacin. As a result, public health agencies have identified drug resistantCampylobacteras a serious threat to public health and have suggested combating the pathogen at the farm-level by reducing its burden within agricultural animal reservoirs. Due to antibiotic restrictions in agricultural animals, reducingCampylobacterburden on the farm requires the identification and development of novel approaches. To this end, our group employed a broad sampling strategy to isolate a diverse collection of bacteriophages that can predateCampylobacter. We successfully isolated 70 bacteriophages from these samples and subjected them to whole-genome sequencing and initial comparative genomic analysis. Following this analysis, we performed dose-response assays by adding increasing concentrations of bacteriophage toC. jejunicultures. From this work, we were able to identify diverse phage groups from multiple sources that correlated with robust inhibition ofC. jejunigrowth. Lastly, we employed transmission electron microscopy to examine the morphology of these bacteriophages and were able to confirm that genetic diversity reflected morphological diversity in these bacteriophages.ImportanceGlobally,Campylobacter jejuniis the most common cause of bacterial-derived gastroenteritis due to its ability to colonize agriculturally relevant animals. The increasing prevalence of antibiotic resistantC. jejunistrains necessitates the development of novel treatments to combat colonization of the animal host. In this study, we describe the isolation of 70 bacteriophages from various environmental sources that infect and killC. jejuni. A robust analysis of the genetic diversity of these phage is described, and transmission electron microscopy is utilized to evaluate morphological differences. This study describes a novel prospecting strategy for isolating bacteriophage that infectC. jejunifrom various environmental sources. In previous studies, bacteriophage that killC. jejunihave been isolated from sewage and pig manure; however, the majority have been isolated from chickens, and have been relatively few in number. We postulate this study increases the likelihood of isolating bacteriophage efficacious at combatingC. jejunicolonization of agricultural animal hosts at the farm-level or treating infected humans.