Lytic Pseudomonas aeruginosa phages LKD16 and LKA1 were locally isolated and morphologically classified as Podoviridae. While LKD16 adsorbs weakly to its host, LKA1 shows efficient adsorption (k a ‫؍‬ 3.9 ؋ 10 ؊9 ml min ؊1). LKA1, however, displays a narrow host range on clinical P. aeruginosa strains compared to LKD16. Genome analysis of LKD16 (43,200 bp) and LKA1 (41,593 bp) revealed that both phages have linear double-stranded DNA genomes with direct terminal repeats of 428 and 298 bp and encode 54 and 56 genes, respectively. The majority of the predicted structural proteins were experimentally confirmed as part of the phage particle using mass spectrometry. Phage LKD16 is closely related to bacteriophage KMV (83% overall DNA homology), allowing a more thoughtful gene annotation of both genomes. In contrast, LKA1 is more distantly related, lacking significant DNA homology and showing protein similarity to KMV in 48% of its gene products. The early region of the LKA1 genome has diverged strongly from KMV and LKD16, and intriguing differences in tail fiber genes of LKD16 and LKA1 likely reflect the observed discrepancy in infection-related properties. Nonetheless, general genome organization is clearly conserved among KMV, LKD16, and LKA1. The three phages carry a single-subunit RNA polymerase gene adjacent to the structural genome region, a feature which distinguishes them from other members of the T7 supergroup. Therefore, we propose that KMV represents an independent and widespread group of lytic P. aeruginosa phages within the T7 supergroup.Two decades after the completion of the genome sequence of coliphage T7 (13), the T7 supergroup comprises 13 fully sequenced and highly virulent phages sharing common morphological, biological, and genomic characteristics. Extensive sequencing efforts have shown that the T7 supergroup can be subdivided further into distinct subgroups of phages that display more similarity to each other than to other members of the supergroup. Phages closely related to T7 (the T7 sensu stricto subgroup) include coliphages T3 (35) and K1F (46), Yersinia phages A1122 (15) and Ye03-12 (36), and Pseudomonas phage gh-1 (23). One of the major distinctive characteristics of the T7 group was originally defined as the presence of a single-subunit phage RNA polymerase that binds phagespecific promoters. However, marine phages VpV262 and SIO1 share extensive homology with T7 but lack the phage RNA polymerase, probably constituting an ancient branch of the T7 supergroup (18). The discovery of a functional sitespecific integrase in the genome of the marine T7-like phage P-SSP7 (M. B. Sullivan, personal communication) and of a T7-like prophage in the genome of Pseudomonas putida KT2440 (33) has led to a further breakdown of strict classification boundaries. Recently, an SP6 subgroup was proposed, containing the slightly more diverged Salmonella phage SP6 and coliphages K1-5 and K1E. The genome organization of these phages resembles that of T7, but numerous insertions and deletions throughout the genome...

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Escherichia coli-associated urinary tract infections (UTIs) are among the most common bacterial infections in humans. UTIs are usually managed with antibiotic therapy, but over the years, antibiotic-resistant strains of uropathogenic E. coli (UPEC) have emerged. The formation of biofilms further complicates the treatment of these infections by making them resistant to killing by the host immune system as well as by antibiotics. This has encouraged research into therapy using bacteriophages (phages) as a supplement or substitute for antibiotics. In this study we characterized 253 UPEC in terms of their biofilm-forming capabilities, serotype, and antimicrobial resistance. Three phages were then isolated (vB_EcoP_ACG-C91, vB_EcoM_ACG-C40 and vB_EcoS_ACG-M12) which were able to lyse 80.5% of a subset (42) of the UPEC strains able to form biofilms. Correlation was established between phage sensitivity and specific serotypes of the UPEC strains. The phages’ genome sequences were determined and resulted in classification of vB_EcoP_ACG-C91 as a SP6likevirus, vB_EcoM_ACG-C40 as a T4likevirus and vB_EcoS_ACG-M12 as T1likevirus. We assessed the ability of the three phages to eradicate the established biofilm of one of the UPEC strains used in the study. All phages significantly reduced the biofilm within 2–12 h of incubation.

Pseudomonas aeruginosa bacteriophage phiKMV requires type IV pili for infection, as observed from the phenotypic characterization and phage adsorption assays on a phage infection-resistant host strain mutant. A cosmid clone library of the host (P. aeruginosa PAO1) genomic DNA was generated and used to select for a clone that was able to restore phiKMV infection in the resistant mutant. This complementing cosmid also re-established type IV pili-dependent twitching motility. The correlation between bacteriophage phiKMV infectivity and type IV pili, along with its associated twitching motility, was confirmed by the resistance of a P. aeruginosa PAO1DeltapilA mutant to the phage. Subcloning of the complementing cosmid and further phage infection analysis and motility assays suggests that a common regulatory mechanism and/or interaction between the ponA and pilMNOPQ gene products are essential for bacteriophage phiKMV infectivity.