**10. Challenges to build phage libraries**

The main challenges in treating phage are:


To address latter problem, many pharmaceutical companies are reluctant to committed resources to improve treatment and therapy. That is because phage treatment is almost 100 years old, making it difficult to patent and raise income to allow for the initial cost of development. Lack of regulatory permission to manage the treatment of the page is problematic. Phage cocktails need to be customized for each patient's infection and regularly organized as the bacteria mutate and improve resistance as shown in **Figure 5**. Regulatory agencies such as the US Food and Drug Administration (FDA) currently do not have the necessary review and approval mechanisms to be able to accept your identity and adapt to a greater degree. The experimental design that benefits from genomic sequence and mass spectrometry will soon meet the need for rapid and accurate microbial identification. A second barrier to phage treatment, the need for easily accessible therapeutic phage, could ultimately be met to some extent by the U.S Medical Research Centre and different groups around the world are presently building phage libraries as shown in **Table 2** [63].

Looking forward, other technological innovations could help make the phage treatment more specific and help with patent issues. For an example, phages can at last be developed using CRISPR/Cas9 genetic engineering strategies to kill only

### **Figure 5.**

*Phage display method to build library of peptides and proteins variants (source: Almagro et al. [62]).*


### **Table 2.**

*Example of Phage display antibody libraries.*

### *Role of Phage Therapy in COVID-19 Infection: Future Prospects DOI: http://dx.doi.org/10.5772/intechopen.96788*

resistant micro-organism. Some agencies there may also be eligible for patents on separate phage or phage cocktails, making them a viable commercial investment [63].

No matter what the future holds for the treatment of the phages, most experts agree that the phage treatment will never completely replace antibiotics. Instead, this method can be used in combination with antibiotics, or as a last resort to protect patients with diseases that have not responded to other treatments. Given the alarming increase in the number of life-threatening multidrug- resistant diseases in recent years, the need to investigate the potential role of phage and other alternative to antibiotic treatments is urgently required [64, 65].

### **11. Conclusion**

The progressing SARS-CoV-2 related COVID-19 pandemic is persistently emerging worldwide and signifying the greatest spotlight on public health, education, travels, and monetary conditions in the current world. As irresistible situations have no borders because there is no single specific therapy that may give effective responses toward COVID-19. Thus, a worldwide activity intends to make phage therapy worldwide overall accessible is required. This obviously requires an active joint effort between countries for overcoming logistic and administrative challenges and among clinicians and researchers for filling current knowledge gap and encouraging advances in the field.

How would it be advisable for us to deal with the current infection prevention and control a strategy which also works after the epidemic? How could we react to similar contagious diseases in the future? These are open questions which require further discussion and research. While phages may have the potential to play a role in the current pandemic, it is also very important to understand that there is no magic stick for this pandemic. The current situation highlights the urgency for adhering to clinical pharmacology, therapeutic, preventative and diagnostics interventions to optimize COVID-19 therapies. The instant and cell free production of synthetic phages, whether designed or not? This had considerable advantages over classically produced natural phages. Implementation of the right patient, right drug, right dosage, and right timing approach helps to reduce the rate of infection. Finally, adaptive designs for COVID-19 will lead to the development of more vigorous infectious disease research infrastructure and funding to help mitigate future pandemics.

### **Acknowledgements**

We would like to thanks Microbiologists and Junior Residents from the Department of Microbiology, Baba Raghav Das Medical College Gorakhpur, UP for providing support in the preparation of this article. We would like to thanks to our laboratory technicians (Mr. Umesh Chaudhary, Mr. Akhilanand Rai, Mr. Jagmohan Prasad) for their support.

### **Authors' contributions**

This work was carried out in collaboration among all authors. Scientific data collection was performed by authors AKS, VG, and AK. The first draft of the manuscript was written by author VG; data was provided and corrected by authors AKS, and AK. All authors commented on previous versions of the manuscript. All authors read and approved the final manuscript*.*

*Bacteriophages in Therapeutics*
