Project description:Phage therapy is a therapeutic approach to treat multidrug resistant infections that employs lytic bacteriophages (phages) to eliminate bacteria. Despite the abundant evidence for its success as an antimicrobial in Eastern Europe, there is scarce data regarding its effects on the human host. Here, we aimed to understand how lytic phages interact with cells of the airway epithelium, the tissue site that is colonized by bacterial biofilms in numerous chronic respiratory disorders. Using a panel of Pseudomonas aeruginosa phages and human airway epithelial cells derived from a person with cystic fibrosis, we determined that interactions between phages and epithelial cells depend on specific phage properties as well as physiochemical features of the microenvironment. Although poor at internalizing phages, the airway epithelium responds to phage exposure by changing its transcriptional profile and secreting antiviral and proinflammatory cytokines that correlate with specific phage families. Overall, our findings indicate that mammalian responses to phages are heterogenous and could potentially alter the way that respiratory local defenses aid in bacterial clearance during phage therapy. Thus, besides phage receptor specificity in a particular bacterial isolate, the criteria to select lytic phages for therapy should be expanded to include mammalian cell responses.
Project description:The Escherichia coli strain Nissle 1917 (EcN) is used as a probiotic for the treatment of certain gastrointestinal diseases in several European and non-European countries. In vitro studies showed EcN to efficiently inhibit the production of Shiga toxin (Stx) by Stx producing E. coli (STEC) such as Enterohemorrhagic E. coli (EHEC). The occurrence of the latest EHEC serotype (O104:H4) responsible for the great outbreak in 2011 in Germany was due to the infection of an enteroaggregative E. coli by a Stx 2-encoding lambdoid phage turning this E. coli into a lysogenic and subsequently into a Stx producing strain. Since EHEC infected persons are not recommended to be treated with antibiotics, EcN might be an alternative medication. However, because a harmless E. coli strain might be converted into a Stx-producer after becoming host to a stx encoding prophage, we tested EcN for stx-phage genome integration. Our experiments revealed the resistance of EcN towards not only stx-phages but also against the lambda phage. This resistance was not based on the lack of or by mutated phage receptors. Rather the expression of certain genes (superinfection exclusion B (sieB) and a phage repressor (pr) gene) of a defective prophage of EcN was involved in the complete resistance of EcN to infection by the stx- and lambda phage. Obviously, EcN cannot be turned into a Stx producer. Furthermore, we observed EcN to inactivate phages and thereby to protect E. coli K-12 strains against infection by stx- as well as lambda-phages. Inactivation of lambda-phages was due to binding of lambda-phages to LamB of EcN whereas inactivation of stx-phages was caused by a thermostable protein of EcN. These properties together with its ability to inhibit Stx production make EcN a good candidate for the prevention of illness caused by EHEC and probably for the treatment of already infected people.
2018-06-14 | GSE109932 | GEO
Project description:Isolation and characterization of phages against Dickeya sp.
| PRJNA767319 | ENA
Project description:Isolation and Characterization of Phages against Enterobacter spp
Project description:Bacteriophages are potent therapeutics against biohazardous bacteria that are rapidly acquiring multidrug resistance. However, routine administration of bacteriophage therapy is currently impeded by a lack of safe phage production methodologies and insufficient phage characterization. We thus developed a versatile cell-free platform for host-independent production of phages targeting gram-positive and gram-negative bacteria. A few microliters of a one-pot reaction produces effective doses of phages against potentially antibiotic-resistant bacteria such as enterohemorrhagic E. coli (EAEC) and Yersinia pestis, which also possibly pose threats as biological warfare agents. We also introduce a method for transient, non-genomic phage engineering to safely confer additional functions, such as a purification tag or bioluminescence for host detection, for only one replication cycle. Using high-resolution and time-resolved mass spectrometry, we validated the expression of 40 hypothetical proteins from two different phages (T7 and CLB-P3) and identified genes in the genome of phage T7 that express exceptionally late during phage replication. Our comprehensive methodology thus allows for accelerated reverse and forward phage engineering as well as for safe and customized production of clinical-grade therapeutic bacteriophages.
Project description:This study analysed the temporal transcriptional response of L. lactis UC509.9 undergoing infection with either Tuc2009 or c2, representing phages of two different species (P335 and c2, respectively) of the family Siphoviridae. For the first time, to our knowledge, both DNA microarrays of the host and high resolution tiling arrays of each phage were used provide corresponding data sets of the entire transcriptome at various points post-infection.