What is antimicrobial resistance? AMR emerges when bacteria, fungi, viruses and parasites change in course of time and no longer respond to currently used medicines to treat infections caused by these pathogens. This makes it harder to treat the infections, increasing disease spread, severe illness and even deaths.
In 2019, WHO announced that AMR is among top 10 global public health challenges that threaten humankind. These threats include:
1. Air Pollution and climate Change
2. Noncommunicable diseases (NCDs): for example, cancer, diabetes, and heart disease
3. Global influenza pandemic
4. Fragile & vulnerable settings: areas prone to drought, famine and conflict
5. Antimicrobial resistance (AMR)
6. Ebola & other high-threat pathogens
7. Weak primary healthcare
8. Vaccine hesitancy
9. Dengue & HIV
What are superbugs?
Microorganisms (microbes) especially bacteria that develop resistance against currently used antibiotics and drugs are often referred to as “superbugs.”
In 2017, the WHO published a list of antibiotic-resistant “priority pathogens” that pose the greatest threat to human health and for which we urgently need to develop new antibiotics. This list is divided into three categories according to the urgency of the need for novel antibiotics: critical, high and medium priority.
The critical group includes multidrug resistant bacteria that pose high risk in hospitals, nursing homes and among patients that need ventilators and blood catheters. These superbugs include Acinetobacter, Pseudomonas and bacteria belonging to Enterobacteriaceae family e.g., Klebsiella, E. coli, Serratia and Proteus. These pathogens can cause deadly infections such as bloodstream infections and pneumonia.
The high and medium priority categories include other increasingly drug-resistant bacteria that cause more common diseases such as gonorrhea and food poisoning eg, Salmonella.
WHO priority pathogens list
Priority 1: Critical
Acinetobacter baumannii
Pseudomonas aeruginosa
Enterobacteriaceae
Priority 2: High
Enterococcus faecium, Staphylococcus aureus, Helicobacter pylori, Campylobacter spp, Salmonellae, Neisseria gonorrhea
Priority 3: Medium
Streptococcus pneumonia, Haemophilus influenza, Shigella spp.
What are the ESKAPE pathogens?
They are six highly virulent and antibiotic resistant bacteria pathogens. ESKAPE is the acronym for these six nasty pathogens. They are:
Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumonia, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter spp.
Causes of AMR
As bacteria naturally develop resistance against antibiotics, it’s impossible to control it. But AMR resistance has been accelerated in the past few decades by our abuse, overuse and misuse of antibiotics. The overuse and misuse of antibiotics are, therefore, crucial factors leading to the emergence of superbugs. When you stop taking antibiotics before the prescribed full course is completed, you’re encouraging bacteria to develop resistance. This is one kind of abuse/misuse of antibiotics. Another factor is overuse of antibiotics.
Overuse of antibiotics
One common instance is taking antibiotics when they are not the correct treatment. Antibiotics are usually meant for treating bacterial infections. They are not effective in treating infections caused by viruses. For example, antibiotics can be recommended for strep throat, one type of sore throat caused by bacteria. However, they are not the right treatment for most sore throats, which are caused by viruses.
Some common viral infections not helped by antibiotics include:
Cold (runny nose)
Flu (influenza)
Bronchitis
Most coughs
Some ear infections
Some sinus infections
Stomach flu
COVID-19
Whooping cough.
What will happen if we don’t urgently develop new antibiotics for superbugs?
In that scenario, we face the risk of entering “the pre-antibiotic ear” once again. Deaths may occur due to simple skin infections from injuries, wounds, or burns; childbirth or routine surgical procedures. We need to quickly reinforce our antibiotic arsenal. Or, humankind runs the risk of facing an AMR Armageddon due to the rise of superbugs. It’s high time that doctors, healthcare workers and citizens learn the art of responsible use of antibiotics and other essential medicines.
On the other hand, scientific workers must accelerate the process of developing new and novel types of antibiotics that can fight the nasty antibiotic-resistant bacteria (some fungi are also superbugs, e.g., Candida albicans, Cryptococcus neoformans and Candida auris).
The search for new antibiotics
Several groups of scientists are exploring novel antibiotics by using a variety of strategies including isolation of novel bacteria from extreme ecosystems, repurposing old antibiotics and drugs, genome mining, co-culture approach, synthetic antibiotics, gene editing, isolation of symbiotic bacteria, using AI and new techniques such as iChip etc.
Several new leads have been obtained, but as space is limited, I shall cover these interesting stories of scientific discoveries in a future column.
For now, let’s sample a few prominent leads obtained so far. Novel antibiotics called chaxapetins, chaxamycins and chaxalactins have been discovered from bacteria isolated from the Atacama Desert in Chile; chaxamycins showed activity against several drug-resistant superbugs. Formicamycins are new antibiotics obtained from symbiotic bacteria associated with African ants. Many other novel antibiotics have also been found from bacteria associated with attine ants, termites, moths and wasps. A new antibiotic called lugdunin has recently been discovered from a beneficial bacterium residing inside the human nose. A new compound called halicin has been discovered by MIT scientists using artificial intelligence (AI).
Old drugs such as octapeptins, auranofins and CBS etc. have been repurposed as new antibiotics targeted against superbugs. CBS is a peptic ulcer drug and auranofin is a drug for rheumatoid arthritis.
An entirely new antibiotic called teixobactin was discovered in 2015 by growing individual soil bacterial cultures (which fail to grow in the laboratory) in miniscule chambers in situ in soil using a device called iChip; derivatives of teixobactin are now being developed as new drugs to treat superbugs. New antibiotics have also been discovered from bacteria isolated from marine samples, e.g., anthracimycins that have been shown to be effective against several types of superbugs.
All of us must now practice responsible use of antibiotics. Humanity must jointly observe antibiotic stewardship. We need to drastically reduce the abuse/overuse/misuse of antibiotics. And, we must search the soil far and wide, dig into the bowels of the oceans, and explore the secret interiors of pristine forests for new antibiotics. We have no time to lose; today, superbugs are killing 1.2 million people globally per year; this number is projected to rise to 10 million globally per year by 2050 (at that time, fatalities due to superbugs will surpass those caused by cancers).
(The views expressed is personal)
