Here click here we describe the in depth characterization of a broad host range PB1-like phage with a slight prevalence to clinical isolates. We used an artificial sputum medium to simulate the conditions in the CF lung and investigated the ability of phage JG024 to infect P. aeruginosa and multiply under these conditions. Results and Discussion Isolation and host range of phage JG024 Phages were isolated from sewage as described in Methods. We isolated 59 P. aeruginosa specific phages and used an initial set of 5 different P. aeruginosa strains as the laboratory strains PAO1, PA14 as well as three clinical isolates (BT2, PACF15 and MH19, Table 1) to test the host range. One phage, which was named JG024, was able to conduct

clear lysis on this set of bacterial strains. To determine the host range of JG024 in more detail, we used 19 clinical isolates from CF patients and from urinary tract infections as well as a collection of 100 environmental strains (Table 1). JG024 is able to infect 84% of all tested clinical isolates. Furthermore, JG024 is even capable of infecting a P. aeruginosa mucA mutant

and the clinical isolate BT73, which both showed the same mucoid phenotype. mucA mutants produce large amounts of the exopolysaccharide alginate and mutations in mucA are critical for the conversion of non-mucoid to mucoid P. aeruginosa variants in the lung of CF patients [20, 21]. Additionally, we determined the host range of the phage JG024 with a collection of 100 P. aeruginosa environmental strains isolated from different rivers (Oker, Aller, Weser) in Lower Saxony, Germany. The results showed that JG024 was able to infect selleck inhibitor 50% of the strains. Interestingly, phage JG024 showed a clear lysis for only 45% of the 50 lysed environmental isolates but was able to conduct clear lysis on 68% of the 19 lysed clinical isolates. Table 1 Strains and phages used in this study. Bacterial strain or phage Phenotype or genotype Reference PAO1 wild type [48] PA14 wild type

[49] FRD1 mucoid CF isolate [34] PAO1 ΔmucA PAO1 mucA::aacC1-gfp GmR Sabrina Thoma, this laboratory, unpublished PAO1 ΔpilA pilA inactivated by allelic displacement; tagged with eGFP, TcR, GmR [50] PAO1 ΔfliM fliM inactivated by allelic displacement; tagged with eGFP, TcR, GmR [50] PAO1 ΔalgC PAO1 Tyrosine-protein kinase BLK algC ::aacC1-gfp GmR Julia Garbe, this laboratory, unpublished BT2, BT72, BT73, RN3, RN43, RN45, NN84 clinical CF isolates Medical Highschool Hannover, Germany PACF15, PACF21, PAKL1, PAKL4, PACF60, PACF61, PACF62, PACF63 clinical CF isolate Gerd Döring, Tübingen, Germany Nr. 18, 19, 26, 29 urinary tract infection isolate Michael Hogardt, München, Germany Environmental strains   Katherina Selezska, HZI Braunschweig, Germany JG024 wild type PAO1 LPS specific lytic bacteriophage this study Family affiliation of JG024 To determine family affiliation of phage JG024, we determined the nature of the nucleic acids and the morphology of the phage to assign the family by comparison [22].

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