#AntibioticResistance I: What is Antibiotic Resistance?

Before jumping in on the flurry of hashtags, smiley faces, or any ice-bucket challenges that may come from the anticipated excitement of the first World Antibiotic Awareness Week between November 16th and 22nd, we wanted to explore some important facts about antibiotic resistance and why it requires more of our attention.

The word “antibiotic” means ‘doubting the possibility of life in a particular environment’, or if we were to break the word down, ‘anti’ means against, ‘biotikos’, fit for life – essentially something that is against the fitness for life. The life that it is referring to in this case, is the life of bacteria – tiny organisms that are too small to see with the naked eye. A million of these can fit into the eye of a needle; the number of humans on earth equals the number of bacteria on the palm of a human hand. Bacteria are single-celled organisms that have evolved over billions of years to thrive in every conceivable environment, including those as inhospitable as thermal vents with temperatures as high as 120oC! The benefits that they incur to society are many, including allowing plants to grow, garbage to decay and providing more oxygen to breathe. In fact, there are 10 times as many bacterial cells as human cells in our body, so you could argue that we are really more bacteria than human. Below is a video about role of bacteria in our bodies.

Some bacteria, however, perhaps about 1%, can cause harmful infections in humans. Commonly, these are not very serious, such as sore throats and ear infections. But often they can be more severe, for example, pneumonia and tuberculosis, meningitis (an infection of the brain membrane), blood infections, and so on. Some bacteria can cause chronic illnesses, like gastric cancer, and there is also evidence that bacteria may contribute to coronary heart disease.

Many bacterial illnesses, such as certain types of pneumonia and meningitis, can be prevented by vaccinations that are given in the first year of life. Sometimes, however, they need to be treated with antibiotics. Antibiotics are drugs that work in one of two main ways. Bactericidal antibiotics kill the bacteria by interfering with the formation of the bacterium’s cell wall or cell contents, which protects it from the external environment and regulates the passage of nutrients and waste products into and out of the cell. Bacteriostatic antibiotics stop bacteria from multiplying, by interfering with bacterial protein production, DNA replication and other aspects of bacterial cellular metabolism. The video below shows a visual presentation of how they do this.

The video also highlights how antibacterials cannot target viruses, because their structure and reproductive mechanisms are completely different. Viruses cannot reproduce by themselves. Instead, they infect cells and rely on the cell’s own machinery to make copies of themselves, so antibiotics do not work against viruses.

Antibiotics have been used extremely successfully over the past six or seven decades. Indeed, modern medicine would not be possible without the use of antibiotics. Antibiotics are used not just to treat infections, but also to prevent infections in patients undergoing medical and dental surgeries, and in patients with weakened immune systems. Unfortunately, bacteria are extremely adaptable and highly adept at developing resistance to antibiotics. They do this through natural selection and by exchanging resistance genes. Some strains of bacteria have naturally evolved to be resistant to certain types of antibiotics. But there is often a cost to resistance – if you expend more energy in making proteins to counteract antibiotics, you have less energy available to reproduce efficiently. So susceptible bacteria usually outcompete resistant bacteria for resources, keeping resistant strains in check. When we overuse or misuse antibiotics, however, we kill off susceptible bacteria and create an environment in which resistant bacteria can thrive without competition, leading to widespread resistance. To make matters worse, some bacteria can pass their resistance genes to other, susceptible bacteria, meaning that resistance can spread rapidly in bacterial populations.

The situation is made worse by rampant use of so-called broad-spectrum antibiotics, which are active against a wide range of bacteria and some other fungi and parasites. These are necessary to prevent infections in patients undergoing certain surgeries, but their misuse increases the chances that resistant bacteria will develop. These types of antibiotics will non-specifically kill both harmful bacteria, as well as beneficial bacteria that are part of the normal flora, creating an ideal environment for resistant bacteria to multiply. Narrow-spectrum antibiotics target only a limited range of bacteria, and judicious use helps to limit the exposure of bacteria to antibiotics, keeping resistance in check.  The Joint Program Initiative on Antibiotic Microbial Resistance  created a video not too long ago on antimicrobial resistance and how the different bacteria develop resistance.

Below is another illustrative video on additional types of antibiotic resistance

Antibiotic resistance is an issue of global concern, leading the WHO to publish its first draft Global Action Plan on Antimicrobial Resistance earlier this year, and declare the first ever World Antibiotic Awareness Week. A world without effective antibiotics is a world without modern medicine, and a return to deaths and disabilities from infections that are currently still mostly treatable with a simple course of pills. But the issue of antibiotic resistance is not simply about the prescription and use of antibiotics. It is a system-wide issue that impacts how we develop, produce, market and use drugs, and resolving this issue will require action from many sectors of society. To put some perspective on the scale of the problem, common types of bacteria can reproduce every 20 minutes. With every reproduction cycle, the number of bacteria double, and the chance of some of them developing resistance features increases. Humans reproduce every 20 to 30 years, so bacteria have a huge headstart in terms of adaptation. Before the discovery of teixobactin, a new antibiotic class, earlier this year, there had not been a new antibiotic discovery for about 30 years. It typically takes 10 years from the time a new drug is discovered until it can be introduced into humans, and history tells us that resistant bacteria are identified just a few years after a new antibiotic is introduced. So unless some very big changes happen in how we tackle antibiotic resistance, it is pretty clear that we are fighting a losing battle.

In the next coming blogs we will explore some of these issues, as well as the history of antibiotics, different perspectives on antibiotic resistance affect, as well as what we can do about it. We may ask ourselves, how does antibiotic resistance affect me? If I do not use antibiotics regularly, except when it is prescribed by doctors, is resistance something that I need to worry about? Are people blowing this situation out of proportion to generate fear? What is the reality of the problem? Does it really require several countries to make a commitment to tackle together?

Many of these questions shall be explored in the next couple of blog posts. Until then, take a look at our Antibiotic Awareness Week quiz and resources page!

By Nahal Haghbin and Clarence Tam

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