Isolation, biological and whole Genome Characteristics of a Proteus mirabilis Bacteriophage Strain

Abstract

Abstract Proteus mirabilis is a zoonotic bacterium belonging to the Enterobacteriaceaefamily and is naturally resistant. Studies have shown that drug resistance in Proteus mirabilis is increasing and there is an urgent need for antimicrobial alternatives to antibiotics.Bacteriophages are viruses that infect bacteria and are ubiquitous in the natural environment. Bacteriophages have a specific targeting effect on bacteria, and lyse the host bacteria with little impact on other flora. In this study, four strains of Proteus mirabilis phages were successfully isolated from the sewage of a chicken farm in Sichuan, China, and the biological and genome-wide characteristics of one of the strongest lytic phages Q29 were clarified, and the functional genes and phylogenetic evolution of Q29 phages were studied by comparative genomic analysis. The results showed that the head of Proteus mirabilis bacteriophage Q29 is icosahedral symmetrical, with a diameter of 95 nm and a tail length of 240 nm. Phage Q29 is stable in the range of 37 ℃ to 55 ℃ and under pH 4 to pH 9. The optimal MOI stands at 0.001. The results of one-step growth curve indicates that the incubation period is about 15 min, the outbreak period is about 35 min, and the average cleavage quantity is about 60 PFU/cell. Phage Q29 has a total length of 58 664 bp and encodes 335 ORFs. It does not carry antibiotic resistance genes. Genetic evolutionary analysis showed that the phage was a member of the family Caudalidae and the genus Myotail. This paper provides a good research material for the further development ofProteus mirabilis bacteriophage biologics.