188
M. Irfan et al.
7.2.2.1 Aptamer Against Bacterial Diseases
Microorganisms are evolving and mutating day-by-day. The handling of bacterial
infections is the main challenge. For instance, the increasing cost of healthcare
may nowadays greatly attribute to the growing rate of multidrug-resistant bacteria
and complications in disease treatment accordingly. Furthermore, novel methods of
bacterial treatments are rather limited or just confined to laboratory bench tops. The
aptamer-based personalized therapeutic systems have been found to be a handy tool
in the treatment of bacterial infections, because of their efficient antibiofilm and
antibacterial activities, they can inhibit or reduce the effects of toxins, and inhibit
bacterial invasion to immune cells [53].
The microbial colonies which are embedded in a self-secreted exopolysaccharide
matrix and with ability to adhere the surfaces are considered as biofilms. They are
very important regarding human infections and shown in more than 65% of microbial
infections [54]. Currently available antibiotics cannot penetrate the polysaccharide
layer leading to the difficulty in eradication of biofilms [55]. Antibiotic therapy
against complete treatment of biofilm infections is inadequate alone. The major
aspects of biofilm formation are associated with motility and initial attachment.
It was reported that aptamers have potential to prevent the biofilm formation and
maturation. A flagella-specific aptamer selected against Salmonella choleraesuis
limited the bacterial rotational frequency along with increase in the electrostatic
repulsion of cells and surfaces. In the presence of aptamers, the cells were more
easily attacked by the antibiotics as well. Furthermore, it was concluded in this study
that the use of aptamers for the pretreatment of S. choleraesuis could decrease the
need of high potency antibiotics such as ampicillin in high dose [56].
There is another primary pathogen, Streptococcus pneumoniae, involved in the
bacterial pneumonias and is the main cause of septicemia, meningitis, sinusitis, and
otitis media. Wild-type strains of S. pneumoniae are more invasive for brain and
lungs because of their ability to form biofilms [57]. A DNA aptamer Lyd-3 was
stated as an efficient preventative therapy with effective antibiofilm activity among
the all known DNA aptamers selected against S. pneumoniae (Fig. 7.3). The combinatorial therapy consisting of aptamer-antibiotics conjugate could be a promising
tool to prevent bacterial colonization. Furthermore, application of 1 μM aptamer
reduced the biofilm formation from 100 to 35.8% [58]. It was suggested by the
results that aptamers-based personalized therapy can be used as novel antibiofilm
practice which can help to fight against increased rate of antibiotic resistance. Consequently, aptamers-based personalized therapeutics can offer an opportunity for efficient treatment of chronic infections by complete eradication of biofilm forming
bacteria. Moreover, this devised therapy can reduce the risk of abuse and misuse of
antibiotic administration [59].
Staphylococcus aureus is a part of our microflora, considered as an opportunistic
pathogen which can cause wide range of infections under suitable conditions and
becomes resistant against many antibiotics [59]. S. aureus causes tissue damage
due to alpha toxin which is one of the virulence factors with the ability to form
heptameric pores in target cell membranes. Furthermore, caused by S. aureus alpha
M. Irfan et al.
7.2.2.1 Aptamer Against Bacterial Diseases
Microorganisms are evolving and mutating day-by-day. The handling of bacterial
infections is the main challenge. For instance, the increasing cost of healthcare
may nowadays greatly attribute to the growing rate of multidrug-resistant bacteria
and complications in disease treatment accordingly. Furthermore, novel methods of
bacterial treatments are rather limited or just confined to laboratory bench tops. The
aptamer-based personalized therapeutic systems have been found to be a handy tool
in the treatment of bacterial infections, because of their efficient antibiofilm and
antibacterial activities, they can inhibit or reduce the effects of toxins, and inhibit
bacterial invasion to immune cells [53].
The microbial colonies which are embedded in a self-secreted exopolysaccharide
matrix and with ability to adhere the surfaces are considered as biofilms. They are
very important regarding human infections and shown in more than 65% of microbial
infections [54]. Currently available antibiotics cannot penetrate the polysaccharide
layer leading to the difficulty in eradication of biofilms [55]. Antibiotic therapy
against complete treatment of biofilm infections is inadequate alone. The major
aspects of biofilm formation are associated with motility and initial attachment.
It was reported that aptamers have potential to prevent the biofilm formation and
maturation. A flagella-specific aptamer selected against Salmonella choleraesuis
limited the bacterial rotational frequency along with increase in the electrostatic
repulsion of cells and surfaces. In the presence of aptamers, the cells were more
easily attacked by the antibiotics as well. Furthermore, it was concluded in this study
that the use of aptamers for the pretreatment of S. choleraesuis could decrease the
need of high potency antibiotics such as ampicillin in high dose [56].
There is another primary pathogen, Streptococcus pneumoniae, involved in the
bacterial pneumonias and is the main cause of septicemia, meningitis, sinusitis, and
otitis media. Wild-type strains of S. pneumoniae are more invasive for brain and
lungs because of their ability to form biofilms [57]. A DNA aptamer Lyd-3 was
stated as an efficient preventative therapy with effective antibiofilm activity among
the all known DNA aptamers selected against S. pneumoniae (Fig. 7.3). The combinatorial therapy consisting of aptamer-antibiotics conjugate could be a promising
tool to prevent bacterial colonization. Furthermore, application of 1 μM aptamer
reduced the biofilm formation from 100 to 35.8% [58]. It was suggested by the
results that aptamers-based personalized therapy can be used as novel antibiofilm
practice which can help to fight against increased rate of antibiotic resistance. Consequently, aptamers-based personalized therapeutics can offer an opportunity for efficient treatment of chronic infections by complete eradication of biofilm forming
bacteria. Moreover, this devised therapy can reduce the risk of abuse and misuse of
antibiotic administration [59].
Staphylococcus aureus is a part of our microflora, considered as an opportunistic
pathogen which can cause wide range of infections under suitable conditions and
becomes resistant against many antibiotics [59]. S. aureus causes tissue damage
due to alpha toxin which is one of the virulence factors with the ability to form
heptameric pores in target cell membranes. Furthermore, caused by S. aureus alpha