Abstract:[Objective] To analyze the prophages carried by 82 strains of Acinetobacter baumannii with completely sequenced genomes, then identify antibiotic resistance genes and virulence factors encoded by prophages. [Methods] Phage Search Tool Enhanced Release (PHASTER) software was used to predict the prophages carried by A. baumannii. The Comprehensive Antibiotic Research Database (CARD) and Virulence Factors Database (VFDB) online analysis software were used to predict the antibiotic resistance genes and virulence factors encoded by the prophages, respectively. [Results] A total 472 prophages were found, of which 201 were "intact", 91 were "questionable", and 180 were "incomplete". On average, at least two intact prophages were carried per A. baumannii genome. The percentage of the prophage genome ranged between 4% and 6% in each A. baumannii genome. Twenty-nine out of the 472 prophages carried 77 resistance genes, which belong to 14 different antimicrobial types, could be grouped into 15 different drug families, and could be classified into six antibiotic resistance mechanisms. One hundred and thirty-two out of the 472 prophages encode putative virulence genes, grouped into 38 virulence gene and 34 virulence factor classes. Most of these prophages encode one or two virulence factors, and a few of them encode three or more virulence factors. Analysis of component ratios of possible virulence factor host sources indicated Neisseria meningitidis, Shigella dysenteriae, and Legionella pneumophila, as well as A. baumannii, as host sources.[Conclusion] A. baumannii generally carries prophages, but the proportion of prophage genes in the genome of A. baumannii is not high. Some prophages carry antibiotic resistance genes, mainly aminoglycosides, sulfonamides, and beta-lactams. Nearly 30% of the prophages carry virulence genes. Prophages may play an important role in the acquisition and spread of antibiotic resistance, and evolution of pathogenicity in A. baumannii.
