PHAGE_TIM2

The rise of antibiotic resistance poses a global problem and could potentially lead to a high mortality rate due to bacterial infections. To avoid this, alternative therapeutic options should be explored. One of these options is lytic bacteriophage therapy, where orally ingested phages are used to treat bacterial infections. Well-designed and described research on effectivity of oral bacteriophage therapy is lacking, therefore the aim of this study was to study whether the in vitro model of the colon (TIM-2) could be used to investigate the survival and efficacy of therapeutic bacteriophages. For this, an antibiotic-resistant (CmR) E. coli (pGK11) was used in combination with a corresponding bacteriophage. For the survival study, the TIM-2 model was inoculated with the microbiota of healthy individuals and a standard feeding (SIEM) was fed over the course of the 72 hour experiment. To test the bacteriophage, different interventions were carried out: i) SIEM as a control run, ii) SIEM spiked with high titer phage effective against E. coli(pGK11) (1 mL of 1010 PFU), iii) SIEM spiked with both E. coli(pGK11) (~106 CFU/mL TIM-2 content) and its phage, iv) SIEM spiked with a dose of E. coli(pGK11) ~108 CFU/mL) and multiple shots of the phage. Survival of bacteriophages and bacteria was followed by plating of the lumen samples at different time points 0, 2, 4, 8, 24, 48, and 72 hours. In addition, the stability of the bacterial community was determined with the use of 16S rRNA sequencing of the V3-V4 gene region. Results showed that the phage titers could be decreased by activity from the commensal microbiota. Levels of the phage host (here E.coli) were decreased in the interventions with the phage shot. Multiple shots did not seem to be more effective than a single shot. At the same time, the bacterial community was not disturbed and remained stable throughout the experiment, which is in stark contrast to treatment with antibiotics. This high specificity shows that phage therapy could be a promising alternative to antibiotic treatment in treating GI infections, because the microbial community is less affected.