Post-antibiotic era: what are the alternatives?

Alexander Fleming accidentally discovered antibiotics almost ninety years ago. He noticed that some molds had grown on a Petri plate wherever bacteria could not grow. This unintentional invention led to the prevention of infectious diseases by an antimicrobial compound that is commonly known as penicillin. This 'magic bullet' has eliminated several previously lethal infections and increased the life expectancy of the patients. Many antibiotics had been discovered at that time, and inappropriately used in various medical conditions whether or not they would be particularly useful. Gradually, bacteria learned how to fight against antibiotics and became resistant to several antibiotics.

The World Health Organisation (WHO) cited antibiotic resistance as a serious global health issue for every part of the world by publishing its first comprehensive report on antibiotic resistance in 2014. The situation in Bangladesh is not different from this perspective. Isolations of multi-drug resistance (MDR) bacteria from the patients have been increased sharply in recent years in Bangladesh.

Over the counter selling of antibiotics and inappropriate use of antibiotics in agriculture has worsened the situation. Alarmingly some of these bacteria are resistant to the new class of antibiotics also.

 Antibiotics either kill the bacteria or inhibit the growth of the bacteria so that our immune system can kill the bacteria to clear the infection. Antibiotics can be divided into several groups based on their modes of action in the bacterial cells, chemical structures, and the types of bacteria they are active in. However, bacteria can employ various mechanisms to become resistant against antibiotics like modification of the enzymes, changing the expression of the target, reducing the permeability of the membrane, destroying the antibiotics, and antibiotic efflux.

 Lately, the discovery of the new antibiotic class has been slow. Only a few antibiotics came to market in the last 18 years compared to the early age of antibiotic development. One of the reasons for the slowing down of the discovery of new antibiotics is that several billion dollars are required for the research and extensive testing before the release of an antibiotic in the market.

 In the context of the current situation, few alternatives have been proposed by scientists. A study published in The Lancet Infectious Diseases journal in 2016 suggested several alternative methods to fight against microbial infections. One of the alternatives is antibodies. Antibodies can play a significant role in this situation. Antibodies either bind to the virulence factors of the microorganisms or bind to the pathogen to inactive it. Antibody therapy is a low-risk and historically safe to use technology. Raxibacumab is a monoclonal antibody that was approved in 2012 to treat inhaled anthrax.

 Another method is to use viruses (also known as bacteriophages) to eliminate bacteria. The practice of using bacteriophages to reduce bacterial infection is an old technique and has been utilised before the era of antibiotics. Recently, in the USA and Canada, phage therapy has been used on patients with cystic fibrosis in an experimental basis.

 Vaccines have the potential to fight against bacterial infections. There are several types of vaccines, and those vaccines help our immune cells to generate memories so that those cells can effectively recognise the infectious agents and clear the infection.

 Antibiotic-resistant bacteria increase the fatality rate in bacterial infections. It is a public health problem of substantial magnitude. Proper uses of the antibiotics help us to reduce the bacterial resistance to the antibiotic and increase the efficacy of the existing antibiotics. Although the discovery of a new class of antibiotics dried up, some alternative methods can be implemented to fight against bacterial infections. These alternative methods may serve as a ray of hope in the dark age of the post-antibiotic era.

The writer is an Assistant Professor at the Department of Biochemistry and Microbiology, North South University, Bangladesh.

E-mail: sabbir.shuvo@northsouth.edu