218
producing E. coli (ESBL-EC) which renders the treatment of urinary tract infections with E. coli pathogen more difficult (Pena et al. 1997). The worst scenario is
observed in cases where the pathogens are resistant against all the recommended
antibiotics for the treatment of the infection. The presence of multi drug resistant
strains along with extensively drug resistant (XDR) strains lead to the urgent need
for the discovery of new drugs that will be capable to fight urinary tract infections.
The use of phages as an alternative seems to be very promising and in comparison,
to antibiotic use, they seem to have many advantages. The ways that phages can be
used are monophage therapies in which only one phage type is used and polyphage
therapies in which more phage types or a cocktail of phages are used. When polyphage therapies are used, the rise of pathogenic bacteria is avoided, the host range
is increased and they are efficient against biofilm forming infections. Genetically
engineered phages are a breakthrough and are an emerging field of interest for scientists’ research nowadays. With their use, they can obtain the desirable characteristics that phages should have to be used effectively against antibiotic resistant
bacteria. Phage lytic enzymes or proteins, which are endolysins and virion associated lysins (VALs), are molecules that have antibacterial properties. They are produced from phages and through some mechanisms; they cause breakage of the
bacterial cell wall. Another therapeutic option is the use of phages in combination
with antibiotics, which act in synergism. This combination aims to fight resistant
bacterial strains (Malik et al. 2019; Goodridge 2010; Lehman and Donlan 2015;
Moller-Olsen et al. 2018; Fischetti 2005; Rodriguez et al. 2011).
9.8 Antibacterial Drug Discovery Using Fecal
Microbiota Transplantation
The human gut microbiota (bacteria, archaea, viruses, and microeukaryotes) has the
largest population of microorganisms in the human body (Hollister et al. 2014). It
usually remains balanced and quite persistent/resilient but when the human organism is exposed to antibiotics, the balance changes (Cho and Blaser 2012). Moreover,
bacterial populations from the normal microflora could disappear due to the broad
spectrum effect of some antibiotics. Such changes further implicate the state of
human health and new antibiotic related diseases occur (Langdon et al. 2016; Yoon
and Yoon 2018). A frequent example of this is susceptibility to the development of
infections, which can become chronic conditions over time. Thus, an alternative
strategy i.e. the fecal microbiota transplantation was developed.
Fecal microbiota transplantation (FMT) is a type of bacteriotherapy (Khoruts
et al. 2010; Wilson et al. 2019). It is also known as stool transplantation because the
therapeutic method consists of transferring the entire balanced stool population
from a healthy donor to a patient with Clostridium difficile infection (CDI). The
stool is usually fused with sterile 0.9% saline to create a liquid mixture, which is
then transferred to the gastrointestinal tract of the patient (Mullish et al. 2018). Once
A. Valsamatzi-Panagiotou et al.
producing E. coli (ESBL-EC) which renders the treatment of urinary tract infections with E. coli pathogen more difficult (Pena et al. 1997). The worst scenario is
observed in cases where the pathogens are resistant against all the recommended
antibiotics for the treatment of the infection. The presence of multi drug resistant
strains along with extensively drug resistant (XDR) strains lead to the urgent need
for the discovery of new drugs that will be capable to fight urinary tract infections.
The use of phages as an alternative seems to be very promising and in comparison,
to antibiotic use, they seem to have many advantages. The ways that phages can be
used are monophage therapies in which only one phage type is used and polyphage
therapies in which more phage types or a cocktail of phages are used. When polyphage therapies are used, the rise of pathogenic bacteria is avoided, the host range
is increased and they are efficient against biofilm forming infections. Genetically
engineered phages are a breakthrough and are an emerging field of interest for scientists’ research nowadays. With their use, they can obtain the desirable characteristics that phages should have to be used effectively against antibiotic resistant
bacteria. Phage lytic enzymes or proteins, which are endolysins and virion associated lysins (VALs), are molecules that have antibacterial properties. They are produced from phages and through some mechanisms; they cause breakage of the
bacterial cell wall. Another therapeutic option is the use of phages in combination
with antibiotics, which act in synergism. This combination aims to fight resistant
bacterial strains (Malik et al. 2019; Goodridge 2010; Lehman and Donlan 2015;
Moller-Olsen et al. 2018; Fischetti 2005; Rodriguez et al. 2011).
9.8 Antibacterial Drug Discovery Using Fecal
Microbiota Transplantation
The human gut microbiota (bacteria, archaea, viruses, and microeukaryotes) has the
largest population of microorganisms in the human body (Hollister et al. 2014). It
usually remains balanced and quite persistent/resilient but when the human organism is exposed to antibiotics, the balance changes (Cho and Blaser 2012). Moreover,
bacterial populations from the normal microflora could disappear due to the broad
spectrum effect of some antibiotics. Such changes further implicate the state of
human health and new antibiotic related diseases occur (Langdon et al. 2016; Yoon
and Yoon 2018). A frequent example of this is susceptibility to the development of
infections, which can become chronic conditions over time. Thus, an alternative
strategy i.e. the fecal microbiota transplantation was developed.
Fecal microbiota transplantation (FMT) is a type of bacteriotherapy (Khoruts
et al. 2010; Wilson et al. 2019). It is also known as stool transplantation because the
therapeutic method consists of transferring the entire balanced stool population
from a healthy donor to a patient with Clostridium difficile infection (CDI). The
stool is usually fused with sterile 0.9% saline to create a liquid mixture, which is
then transferred to the gastrointestinal tract of the patient (Mullish et al. 2018). Once
A. Valsamatzi-Panagiotou et al.