Project description:We analyzed RNA-Seq data of two Staphylococcus aureus strains, Newman and SH1000, infected by Kayvirus phage K. Staphylococcus virus K is used in the phage therapy, its genome is 148 kb long consisting of dsDNA with long terminal repeats, and encodes 233 ORFs and 4 tRNAs. The sampling times 0, 2, 5, 10, 20, and 30 minutes after infection were chosen based on the growth characteristics of the phage K at the two S. aureus strains. From the RNA-Seq data we determined transcriptional profile of the phage K and its hosts, which allowed us to identify differentially expressed genes, ncRNAs, and promotor and terminator sites. Transcription of the phage K genes starts immediately after the infection of bacterial cells and we found a gradual take-over by phage K transcripts in the infected cells. The temporal transcriptional profile of phage K was similar in both strains and the relative expression of phage K genes shows three distinct transcript types – early, middle, and late based on the time they reach maximum expression. The bacterial response to phage K infection is similar to the general stress response. It includes the upregulation of nucleotide, amino acid and energy synthesis and transporter genes and the downregulation of transcription factors. The expression of particular virulence genes involved in adhesion and immune system evasion as well as prophage integrases were marginally affected. This work unveils the versatile nature of phage K infection leading to its broad host range
Project description:Transcriptional profiling of NHDF Cells comparing control untreated fibroblasts with fibroblasts coincubated with three different species of the Borrelia burgdorferi sensu lato group.
Project description:Staphylococcus aureus (S. aureus) is a known pathogen able to infect humans and animals. Human S. aureus isolates are often associated with carriage of Sa3int prophages combined with loss of beta-hemolysin production due to gene disruption, whereas animal isolates are positive for beta-hemolysin associated with absence of Sa3int prophages. Sa3int prophages are known to contribute to staphylococcal fitness and virulence in human host by providing human-specific virulence factors encoded on the prophage genome. Strain-specific differences in regard to phage transfer, lysogenization and induction are attributable to yet unknown staphylococcal factors specifically influencing prophage gene expression. In this work we used tagRNA-sequencing approach to specifically search for these unknown host factors and differences in prophage gene expression. For this purpose, we established a workflow revealing the first direct comparison for differential gene expression analysis on two distinct single-lysogenic S. aureus isolates. Further, global gene expression patterns were investigated in two S. aureus isolates upon mitomycin C treatment and compared to uninduced conditions. This provides new insights into the tightly linked host-phage interaction network.
Project description:Environmental cues sometimes have a direct impact on phage particle stability, as well as bacterial physiology and metabolism, having a profound effect on phage infection outcome. Here, we explore the impact of temperature on the interplay between phage Kayvirus rodi (phiIPLA-RODI) and its host, Staphylococcus aureus. Our results show that phiIPLA-RODI is a more effective predator at room (25 °C) compared to body temperature (37 °C) against planktonic cultures of several strains with varying degrees of phage susceptibility. This result differs from most known examples of temperature-dependent phage infection, in which optimum infection is correlated with the host growth rate. Further characterization of this phenomenon was carried out with strains IPLA15 and IPLA16, whose respective MICs were 7 log units and a 1-log unit higher at 37 °C than at 25 °C. Our results demonstrated that the phage also had a greater impact at room temperature during biofilm development and for the treatment of preformed biofilms. There was no difference in phage adsorption between the two temperatures for strain IPLA16. Conversely, adsorption of phiIPLA-RODI to IPLA15 was reduced at 37 °C compared to 25 °C. Moreover, confocal microscopy analysis indicated that the biofilm matrix of both strains has a greater content of PIA/PNAG at 37 °C than at 25 °C. Regarding infection parameters, we observed longer duration of the lytic cycle at 25 °C for both strains, and infection of IPLA15 by phiIPLA-RODI resulted in a smaller burst size at 37 °C than at 25 °C. Finally, we also found that the rate of phage resistant mutant selection was higher at 37 °C for both strains. Altogether, this information highlights the impact that bacterial responses to environmental factors have on phage-host interactions. Moreover, phage phiIPLA-RODI appears to be a highly effective candidate for biofilm disinfection at room temperature, while its efficacy in biofilm-related infections will require combination with other antimicrobials.