*Efficiency of Treatment Targeted on Gut Microbiota in Inflammatory Bowel Diseases… DOI: http://dx.doi.org/10.5772/intechopen.108664*

second colonoscopy at week 6. The primary endpoint consisted of the implantation of the donor microbiota at week 6 (Sorensen index > 0.6). In this study, eight patients received FMT and nine patients sham transplantation. Data revealed that none of the patients included reached the primary endpoint. Because a low similarity index between donor and recipient gut microbiota in several patients was detected, authors assume that a single FMT might not be sufficient to induce significant changes. However, FMT demonstrated to be more efficient over sham transplantation in decreasing Crohn's Disease Endoscopic Index of Severity (CDEIS) and CRP level, and a higher colonization by donor microbiota leads to the maintenance of remission. These results must be confirmed in larger studies.

At this time, we can conclude that, although there were some clinical benefits seen in UC patients treated with FMT, there is still some uncertainty regarding the rate of serious adverse events related to FMT treatment in IBD patients. Moreover, further studies are needed to evaluate the efficacy of FMT treatment for induction of remission in CD patients (**Figure 3**). Future research should define the optimal parameters of FMT (delivery route, frequency, volume, type of preparation, type of donor, and also the type of IBD and severity of the attack). Also, more data regarding long-term maintenance of remission with FMT treatment in IBD patients are needed, along with validation regarding long-term safety of FMT.

## **2.9 Phage therapy**

Research studies assessed the association of the enteric virome and IBD, showing alterations of the virome patients with IBD. One study showed an increased

**Figure 3.** *Fecal microbiota transplantation regimen.*

number of phages infecting some bacteria such as Clostridiales, Alteromonadales, and Clostridium acetobutylicum, along with a higher number of viruses from the Retroviridae family in IBD patients [128, 129]. A follow-up study identified a significantly higher diversity from phages associated with a reduction in bacterial diversity in subjects with IBD vs. controls. In a pediatric population with IBD, Caudovirales were more significantly represented [130]. Higher abundance and reduced diversity of phages and a decreased number of phage-related functions in patients with UC [131] were discovered; these aspects suggest the possibility of new treatments targeting the virome in this IBD subtype.

"Phage therapy" signifies the modulation of phageome, and by this, the bacteriome of an individual suffering from a disease considered to stem from bacterial origin (**Figure 4**). It includes several steps [132]:


In this regard, phages engineered to be usable for treatment should not be recognized by the immune system of the host. Several studies revealed the ability of phages to stimulate the production of antibodies, findings that could assign phages negative effects on the gut environment. However, there are data showing that phages may also have anti-inflammatory effects. For example, the modulation of NF-κB activity by Staphylococcus aureus phage was discovered [133]. It is considered that the systemic presence of phages could play a crucial role in diminishing the immune response and the development of some auto inflammatory/inflammatory diseases including IBD.

#### **Figure 4.**

*Phage therapy modulation. A—the phage attachments to the host; the incorporation of the genetic information into the DNA of the host; B—the administration of the therapeutic agent; C—the degradation of the bacterium.*
