ABSTRACT
Phage therapy has a long tradition in Eastern Europe, where preparations are comprised of complex phage cocktails whose compositions have not been described. We investigated the composition of a phage cocktail from the Russian pharmaceutical company Microgen targeting Escherichia coli/Proteus infections. Electron microscopy identified six phage types, with numerically T7-like phages dominating over T4-like phages. A metagenomic approach using taxonomical classification, reference mapping and de novo assembly identified 18 distinct phage types, including 7 genera of Podoviridae, 2 established and 2 proposed genera of Myoviridae, and 2 genera of Siphoviridae. De novo assembly yielded 7 contigs greater than 30 kb, including a 147-kb Myovirus genome and a 42-kb genome of a potentially new phage. Bioinformatic analysis did not reveal undesired genes and a small human volunteer trial did not associate adverse effects with oral phage exposure.
Subject(s)
Bacteriophages , Biological Therapy/adverse effects , Biological Therapy/methods , Escherichia coli Infections/therapy , Metagenomics/methods , Proteus Infections/therapy , Administration, Oral , Bacteriophages/classification , Bacteriophages/genetics , Bacteriophages/ultrastructure , Gram-Negative Bacteria/classification , Gram-Negative Bacteria/virology , Humans , Microscopy, Electron, Transmission , Myoviridae/classification , Myoviridae/genetics , Myoviridae/ultrastructure , Podoviridae/classification , Podoviridae/genetics , Podoviridae/ultrastructure , Russia , Siphoviridae/classification , Siphoviridae/genetics , Siphoviridae/ultrastructure , Treatment OutcomeABSTRACT
The genomic diversity of 99 T4-like coliphages was investigated by sequencing an equimolar mixture with Illumina technology and screening them against different databases for horizontal gene transfer and undesired genes. A 9-phage cocktail was given to 15 healthy adults from Bangladesh at a dose of 3×10(9) and 3×10(7) plaque-forming units and placebo respectively. Phages were detected in 64% of the stool samples when subjects were treated with higher titer phage, compared to 30% and 28% with lower-titer phage and placebo, respectively. No Escherichia coli was present in initial stool samples, and no amplification of phage was observed. One percent of the administered oral phage was recovered from the feces. No adverse events were observed by self-report, clinical examination, or from laboratory tests for liver, kidney, and hematology function. No impact of oral phage was seen on the fecal microbiota composition with respect to bacterial 16S rRNA from stool.
