Prevalence of Pf1-like (pro)phage genetic elements among Pseudomonas aeruginosa isolates

- Pf1-like prophages in P. aeruginosa sequenced genomes were defined and analyzed.
- Prevalence of Pf1-like genetic element was examined among 241 strains by PCR.
- More than half of the strains contained at least one Pf1-like genetic element (60%).
- Beside universal, most frequent specific element was Pf4, followed by Pf1 and Pf5.
- Supernatants of some strains with only universal or Pf4 element were infective.

Pf1-like bacteriophages (family Inoviridae) of Pseudomonas aeruginosa can contribute to bacterial short term evolution and virulence. Here we examine Pf1-like (pro)phage diversity and prevalence among different P. aeruginosa isolates. Pf1-like prophages in sequenced genomes of P. aeruginosa were analyzed and grouped into four clades: Pf4, Pf5, Pf7 and Pf-LES. P. aeruginosa strains (n=241) were screened for the presence of universal (primers PfUa and PfUb) and specific Pf1-like genetic elements (Pf1, Pf4 and Pf5). More than half of the strains contained at least one Pf1-like genetic element (60%); universal elements were detected in 56% of the strains, Pf4 in 22%, Pf1 in 18% and Pf5 in 7%. Infectivity experiments confirmed that strains yielding PCR products with either universal or Pf4 specific primers can release infective virions. Based on the high prevalence of Pf1-like (pro)phages, it is necessary to further examine their involvement in P. aeruginosa virulence.