Emergence of resistant strains is the consequence of wholesale abuse of antibiotic drugs, lack of awareness about antibiotic resistance among the individuals and patient's ignorance on antibiotic treatments.
Part of the issue is a lack of knowledge about antibiotics.
Limitations and challenges
Reasons why phages are not the perfect solution for bacteria.
The engineered phage potentially reduced bacterial biofilm cell count by > 100 fold compared to that of wild type phage.
Engineered can be better than regular phage, more specific tasks to be completed.
Anti-phage antibodies may be produced due to the rapid release of endotoxins which might cause major life-threatening immune reactions like anaphylaxis
Use of phages is not perfect and without risk.
Thus, fatal infections can be treated successfully with phages
An end to deadly bacterial disease?
Bacteriophages coexist with the bacterial communities in gastrointestinal tract and are known to play a significant role in restoring intestinal eubiosis by eliminating pathogenic strains. They maintain immune homeostasis
This homeostasis gets disrupted when antibiotics are introduced.
To overcome the limitation of endolysins as antibacterial elements against Gram-negative pathogens, “Innolysins” were designed by combining the enzymatic activity of phage T5-endolysin and its receptor binding protein (RBP)-Pb5 in different configurations.
Genetically modified phage in order to perform a specific task.
Cocktail of varied phages are used to vanquish phage resistant pathogenic bacteria
Tying back to the first paragraph in section four, detailing better what the phage cocktails are used for.
Food-Animal agriculture
Demonstrates uses of phages in agriculture. Details successes of phages used in particular experiments and on particular crops and livestock.
Phage cocktails could also be used to ensure the adequate coverage of common strains and to reduce the probability of phage resistant bacterial mutants
Multiple different phages used at once ensures that if some do not work than at least one phage in the cocktail will work.
Phage cocktails
A mixture of different phages.
The consolidate result of two therapeutic agents is much greater than sum of their individual effects, a fact that brings significantly higher rates of therapy success achieved by synergistic effects.
The sum is greater than the individuals required to create the sum.
apoptosis
programmed (or "natural")cell death
Modified phage
Genetically modified version of conventional phage therapy
Conventional phage therapy
What you would think of when being told "viruses are used to destroy bacteria."
A spectrum of strategies
Modern technology allows multiple ways for phage therapy to occur, whether through genetically engineering viruses or other means.
Polymicrobial biofilms are recognized as a prime factor in the failure of chronic wound healing in timely fashion.
The reason it takes so long for wounds to heal is because the bacteria has a protective layer around it, which prevents it from being killed easily.
rophylactic phage treatment 2 h prior to bacterial challenge showed 100% survival rate while simultaneous application of phage & bacteria showed 72% survival rate and phage application 2 h post bacterial challenge showed 30% survival rate.
The numbers seem to prove the testing worked, as 2 hours post only 30% of the bacteria survived.
Gastrointestinal tract
Phages only target specific bacteria so this could help in not creating problems for the GIT like antibiotics do.
Many in vitro and in vivo studies have demonstrated that phage therapy has been used for the successful treatment of antibiotic resistant pulmonary infections (Pneumonia, and cystic fibrosis), gastrointestinal infections, and topical and wound infections.
Phage therapy has been successful in many cases. Shows the range of issues phage therapy can be used to treat.
The classifications are based upon the evaluation of diverse phage properties such as genome composition, morphology, host range, sequence similarity and pathogenicity
classifications determined by many factors and properties of the phage
The genetic material is enclosed in an icosahedral protein capsid head, a tail (spiral contractile sheath surrounding a core pipe and a baseplate with tail fibers) and surface receptor proteins responsible to recognize specific surface molecules on the host bacterium
Designed to be able to infect and destroy bacteria effectively
Antimicrobial resistance may occur naturally, however the process might be accelerated due to the irrational and overuse of antibiotics leading to the mushrooming of resistant pathogens
exponential growth of resistance in bacteria due to antimicrobials
This emergence and dissemination of antimicrobial drug resistance among pathogens poses an enormous challenge to the public health professionals globally
This is because bacteria are harder to kill, but they can easily kill living organisms
Antimicrobial resistance is a global health problem and one of the leading concerns in healthcare sector.
Too many antimicrobials being used has unfortunately led to bacteria developing the resistance against it.
6. Conclusion
Details current state of CRISPR and Phage technology and lists hopes for the future
The phage cocktail, a combination of different phages, provides a means of decreasing phage resistance.
multiple phages used keeps the bacteria from developing resistance to just one phage
The evolution of phage resistance in bacteria is inevitable.
what is after phages once bacteria become resistant to phages?
With regard to narrow host range issues, phage adsorption requires recognition and binding to specific structures on the bacterial host surface or, in other words, high species or strain specificity. The primary solutions to these issues include modifying the receptor-binding domain [42], [43], [44], [45] or modifying phages to express bacterial biofilm-degrading enzymes [46].
Phages can adapt to small changes, not large changes or bacteria they have no previous experience with
Both research models revealed selective killing and re-sensitisation to antimicrobials
The CRISPR-Cas method works for what they are meant to do
in vivo and in vitro
In vivo - in a living organism In vitro - in a test environment such as Petri dish
only phage, nanoparticle and conjugative delivery
very short list of methods able to be used for the purpose of CRISPR-Cas
Since the pace of emerging antibiotic resistance exceeds that of new antibiotic development
too many antibiotics being used so the bacteria are adapting
viral and non-viral delivery
Viral - with virus Nonviral - bioengineering
Different routes and materials of CRISPR-Cas system delivery and genome editing by antimicrobial CRISPR-Cas system. CRISPR-Cas delivery approaches can be divided into viral and non-viral delivery
to my previous question -- yes. Multiple ways to achieve gene editing
Similar, but not identical, delivery components tend to achieve the same goal, i.e. gene editing.
Many ways to do this method?
Currently, the type II system (CRISPR-Cas9) is the most studied and most frequently used for genome editing
I wonder if this is because it is the easiest or most effective out of all of them.
The phage cocktail decreased the bacterial load in the wound to a greater extent than that in the control group, which used 1% sulfadiazine silver emulsion cream as standard care
Phage is better than traditional medicines/antibiotics, which makes sense seeing as they're specifically made to destroy bacteria
In addition to conventional phage therapy, ‘clustered regularly interspaced short palindromic repeats’ and ‘CRISPR-associated protein’, abbreviated as the CRISPR-Cas system, which is an adaptive immune system of prokaryotes [6], has been adopted as a genomic editing tool and a novel treatment for multidrug-resistant (MDR) bacteria
CRISPR-Cas modifies itself to kill the designated bacteria, despite adaptations of the bacteria. A learner-phage -- learns from experience, it looks like.
However, a lack of randomised controlled trials (RCTs) demonstrating the safety and efficacy of phage therapy, as well as several regulatory issues such as production and marketing authorisation, pose obstacles to its practical use
Good in theory, lacking in data to prove it is efficient.
The CRISPR-Cas system can be delivered into target bacteria in various ways, with phage-based vectors being reported as an effective method. In this review, we briefly summarise the results of randomised control trials on bacteriophage therapy
CRISPR - a method for splicing and removing viral DNA