140
of phage against a specific strain of host (bacteria) restricts the wide application of
phagemids to deliver CRISPR-Cas machinery (Pires et al. 2016). CRISPR-Cas can
also be delivered with conjugative plasmids. However, limited range of hosts, hindrances in plasmid intake and efficiency of conjugation restricts its widespread
application. One of the major hindrances in using Cas9 is its inherent toxicity as
evident in Corynebacterium glutamicum and Synechococcus elongatus (Naduthodi
et al. 2018; Jiang et al. 2017). An alternative to this could be the usage of Cas12 in
place of Cas9 which gave promising results (Hatoum-Aslan et al. 2011; Yosef et al.
2012; Swarts et al. 2012). The field of nanotechnology brought a new dimension in
delivery mechanism of Cas9 system. A plethora of nano systems have been designed
to help the deliver CRISPR-Cas9 assembly (Deng et al. 2019).
6.6.3 Progress in Resistance Against CRISPR-Cas System
to Manage Antimicrobial Resistance in Bacteria
Point mutation in antimicrobial resistance causing gene or the sequence which
CRISPR-Cas system cleaves can hamper the antimicrobial resistance management
in bacteria. Apart from point mutation, insertion and deletion of Cas gene can also
affect the antimicrobial resistance in bacterial species. The obstacles to deliver
CRISPR-Cas are more due to development of resistance towards it. Other than
resistance caused by mutations, the resistance can also occur due to selection of
anti-CRISPR genes that codes for tiny protein molecule which attaches to the key
sequences of CRISPR-Cas network and deactivates the whole system (Vercoe et al.
2013). Escalated specificity and intricate diversity of sequence for anti CRISPRs
(Acrs) shows that Acrs are omnipresent and can be transferred by mobile gene elements like bacteriophage and extrachromosomal determinants to prevent selection
by CRISPR-Cas (Pawluk et al. 2018; Borges et al. 2017; Houte et al. 2016; Jiang
et al. 2013; Pawluk et al. 2016; Harrington et al. 2017).
6.6.4 Judiciary and Legislation on Use of CRISPR-Cas System
to Tackle AMR
To degrade and eliminate antimicrobial resistance causing gene from bacterial population found in nature, using CRISPR-Cas network may have to go through numerous legislative and judicial challenges. Risk evaluation for usage of gene editing
tools on naturally found microbes is crucial. Support of stakeholders becomes necessary to use gene editing tools like CRISPR to overcome the problem of antimicrobial resistance (Carter and Friedman 2016; Adelman et al. 2017).
A. P. Sarma et al.
of phage against a specific strain of host (bacteria) restricts the wide application of
phagemids to deliver CRISPR-Cas machinery (Pires et al. 2016). CRISPR-Cas can
also be delivered with conjugative plasmids. However, limited range of hosts, hindrances in plasmid intake and efficiency of conjugation restricts its widespread
application. One of the major hindrances in using Cas9 is its inherent toxicity as
evident in Corynebacterium glutamicum and Synechococcus elongatus (Naduthodi
et al. 2018; Jiang et al. 2017). An alternative to this could be the usage of Cas12 in
place of Cas9 which gave promising results (Hatoum-Aslan et al. 2011; Yosef et al.
2012; Swarts et al. 2012). The field of nanotechnology brought a new dimension in
delivery mechanism of Cas9 system. A plethora of nano systems have been designed
to help the deliver CRISPR-Cas9 assembly (Deng et al. 2019).
6.6.3 Progress in Resistance Against CRISPR-Cas System
to Manage Antimicrobial Resistance in Bacteria
Point mutation in antimicrobial resistance causing gene or the sequence which
CRISPR-Cas system cleaves can hamper the antimicrobial resistance management
in bacteria. Apart from point mutation, insertion and deletion of Cas gene can also
affect the antimicrobial resistance in bacterial species. The obstacles to deliver
CRISPR-Cas are more due to development of resistance towards it. Other than
resistance caused by mutations, the resistance can also occur due to selection of
anti-CRISPR genes that codes for tiny protein molecule which attaches to the key
sequences of CRISPR-Cas network and deactivates the whole system (Vercoe et al.
2013). Escalated specificity and intricate diversity of sequence for anti CRISPRs
(Acrs) shows that Acrs are omnipresent and can be transferred by mobile gene elements like bacteriophage and extrachromosomal determinants to prevent selection
by CRISPR-Cas (Pawluk et al. 2018; Borges et al. 2017; Houte et al. 2016; Jiang
et al. 2013; Pawluk et al. 2016; Harrington et al. 2017).
6.6.4 Judiciary and Legislation on Use of CRISPR-Cas System
to Tackle AMR
To degrade and eliminate antimicrobial resistance causing gene from bacterial population found in nature, using CRISPR-Cas network may have to go through numerous legislative and judicial challenges. Risk evaluation for usage of gene editing
tools on naturally found microbes is crucial. Support of stakeholders becomes necessary to use gene editing tools like CRISPR to overcome the problem of antimicrobial resistance (Carter and Friedman 2016; Adelman et al. 2017).
A. P. Sarma et al.