The ‘Appelmans protocol’ is used by Eastern European researchers to generate therapeutic phages with novel lytic host ranges. Phage cocktails are iteratively grown on a suite of mostly refractory bacterial isolates until the evolved cocktail can lyse the phage-resistant strains. To study this process, we developed a modified protocol using a cocktail of three Pseudomonas phages and a suite of eight phage-resistant (including a common laboratory strain) and two phage-sensitive Pseudomona aeruginosa strains. After 30 rounds of selection, phages were isolated from the evolved cocktail with greatly increased host range. Control experiments with individual phages showed little host-range expansion, and genomic analysis of one of the broad-host-range output phages showed its recombinatorial origin, suggesting that the protocol works predominantly via recombination between phages. The Appelmans protocol may be useful for evolving therapeutic phage cocktails as required from well-defined precursor phages.

Stenotrophomonas maltophilia is a Gram-negative pathogen causing severe and often refractory illnesses such as pneumonia and bacteremia. We present the genome of phage Salva, a novel S. maltophilia phage that is not closely related to any phages currently deposited in GenBank. The genome is 60,789 bp, containing 102 putative protein-coding genes.

Rhizobium japonicum is a Gram-negative bacterium of interest for research into nitrogen fixation in legumes. This article describes the isolation, sequencing, and annotation of R. japonicum podophage Pasto. While it shows no significant similarity to identified phages, genomic analysis indicates that Pasto may be temperate and is a novel T7-like podophage.

Here, we present the genome of Palo, a T7-like podophage of Rhizobium phaseoli . The genome is 46.3 kb and contains 58 predicted protein-coding genes, including a novel signal-anchor-release (SAR) endolysin, a homolog of the T5 A1 protein required for DNA transfer, and a dual-start holin/antiholin pair.

Achromobacter spp. are ubiquitous Gram-negative bacteria, some of which can cause respiratory tract infections in patients with autoimmune disorders and cystic fibrosis. Bacteriophages have therapeutic and biotechnological potential to combat Achromobacter sp. infections. This announcement details the 42.5-kb genome sequence of the temperate Achromobacter xylosoxidans myophage Mano.

Streptomyces are Gram-negative soil bacteria that can degrade lignin and synthesize antibiotics. Some species cause mycetoma, pneumonitis, and bloodstream infections. Here, we present the genome sequence of the Streptomyces sp. strain Mg1 phage Salutena, a siphovirus in the subfamily Arquatrovirinae . The genome is 51,993 bp, with 90 predicted protein-coding genes.