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the healthy microbes are transplanted, they compete with C. difficile and they suppress its growth. The transplantation is applied to patients who have already been
properly treated with antibiotics but the Clostridium difficile infection has reoccurred twice (Mullish et al. 2018). However, it is possible that a candidate is considered for fecal microbiota transplantation after only one infection, if it is a severe one
with high risk factors for more episodes. According to the American
Gastroenterological Association and the joint British Society of Gastroenterology
(BSG) and Healthcare Infection Society (HIS), caution is advised for immunosuppressed patients or patients with recent bone marrow transplant, cirrhosis, immune
deficiency syndrome (AIDS) or decompensated chronic liver disease. Furthermore,
fecal microbiota transplantation is not recommended for patients with anaphylactic
food allergies. Usually, the fecal microbiota transplantation is performed by colonoscopy or sigmoidoscopy. However, other methods have been used successfully
such as fecal enemas (given through the rectum), nasogastric (nasal), nasoduodenal
or nasojejunal tube into the upper part of the gastrointestinal tract, upper gastrointestinal endoscopy or capsules with frozen fecal microbiota transplantation.
Fecal microbiota transplantation is a very effective therapy that is considered
successful when there is no infection for the next 8 weeks after treatment. The overall success rate varies between 65% and 80% after 1 treatment and 90% to 95%
success after repeated treatments (Meyers et al. 2018; Shogbesan et al. 2018). Such
favorable outcomes only prove fecal microbiota transplantation as a potent alternative to the widely used antibiotics and additionally limit the spread of antibiotic
resistance.
9.9 Antibacterial Drug Discovery Based on Cell Penetrating
Peptides with Antibacterial Activity
In recent years, there has been increased interest in the research field for antimicrobial peptides (AMPs) (Pfalzgraff et al. 2018). Naturally, they are considered part of
the innate immunity in various organisms but the development of synthetic ones has
proven to be quite effective towards various human bacterial pathogens.
Antimicrobial peptides are amphipathic and cationic. Their size is within the range
of 12 and 50 amino acid residues (Fensterseifer et al. 2019). On the other hand, cell
penetrating peptides (CPPs) are exogenous peptides or peptide cargo complexes
with the ability to directly enter cells and deliver their cargo inside them (Kauffman
et al. 2015). The majority of the cell penetrating peptides are amphipathic, have a
net positive charge and do not show any cell specificity (Rodriguez et al. 2014). The
size of a cell penetrating peptide usually varies between 6 and 30 residues (Nakase
et al. 2012). It has been debatable whether antimicrobial peptides and cell penetrating peptides should be separated in different categories or if one of them should be
a subordinate category to the other (Langel 2019). Here we briefly describe some
antimicrobial peptides and cell penetrating peptides divided into 2 categories viz.
9 Drug Discovery for Targeting Drug Resistant Bacteria
the healthy microbes are transplanted, they compete with C. difficile and they suppress its growth. The transplantation is applied to patients who have already been
properly treated with antibiotics but the Clostridium difficile infection has reoccurred twice (Mullish et al. 2018). However, it is possible that a candidate is considered for fecal microbiota transplantation after only one infection, if it is a severe one
with high risk factors for more episodes. According to the American
Gastroenterological Association and the joint British Society of Gastroenterology
(BSG) and Healthcare Infection Society (HIS), caution is advised for immunosuppressed patients or patients with recent bone marrow transplant, cirrhosis, immune
deficiency syndrome (AIDS) or decompensated chronic liver disease. Furthermore,
fecal microbiota transplantation is not recommended for patients with anaphylactic
food allergies. Usually, the fecal microbiota transplantation is performed by colonoscopy or sigmoidoscopy. However, other methods have been used successfully
such as fecal enemas (given through the rectum), nasogastric (nasal), nasoduodenal
or nasojejunal tube into the upper part of the gastrointestinal tract, upper gastrointestinal endoscopy or capsules with frozen fecal microbiota transplantation.
Fecal microbiota transplantation is a very effective therapy that is considered
successful when there is no infection for the next 8 weeks after treatment. The overall success rate varies between 65% and 80% after 1 treatment and 90% to 95%
success after repeated treatments (Meyers et al. 2018; Shogbesan et al. 2018). Such
favorable outcomes only prove fecal microbiota transplantation as a potent alternative to the widely used antibiotics and additionally limit the spread of antibiotic
resistance.
9.9 Antibacterial Drug Discovery Based on Cell Penetrating
Peptides with Antibacterial Activity
In recent years, there has been increased interest in the research field for antimicrobial peptides (AMPs) (Pfalzgraff et al. 2018). Naturally, they are considered part of
the innate immunity in various organisms but the development of synthetic ones has
proven to be quite effective towards various human bacterial pathogens.
Antimicrobial peptides are amphipathic and cationic. Their size is within the range
of 12 and 50 amino acid residues (Fensterseifer et al. 2019). On the other hand, cell
penetrating peptides (CPPs) are exogenous peptides or peptide cargo complexes
with the ability to directly enter cells and deliver their cargo inside them (Kauffman
et al. 2015). The majority of the cell penetrating peptides are amphipathic, have a
net positive charge and do not show any cell specificity (Rodriguez et al. 2014). The
size of a cell penetrating peptide usually varies between 6 and 30 residues (Nakase
et al. 2012). It has been debatable whether antimicrobial peptides and cell penetrating peptides should be separated in different categories or if one of them should be
a subordinate category to the other (Langel 2019). Here we briefly describe some
antimicrobial peptides and cell penetrating peptides divided into 2 categories viz.
9 Drug Discovery for Targeting Drug Resistant Bacteria