Antibiotics discovered in 1928 by British scientist Sir Alexnder Fleming revolutionized the treatment of infectious diseases. Before the antibiotics era, several infectious diseases like pneumonia, smallpox, cholera and typhoid were the leading cause of death worldwide. Antibiotics came as an effective cure, saving millions of lives. The effectiveness of antibiotics and other antimicrobials has been threatened by a phenomenon called antimicrobial resistance (AMR), which makes infections resistant to drugs. The first documented case of penicillin resistance was seen in 1947. Since then, the resistance to the drugs has become a cause of concern.
WHO has declared that anti-microbial resistance is a global health and development threat and is one of the top 10 global public health threats facing humanity, requiring urgent action. The terms antimicrobial and antibiotic are often used interchangeably. According to a multicentre study published in The Lancet in 2019, 1.27 million deaths were attributed to drug-resistant infections worldwide. About 10 million people could die annually from AMR by 2050.
What is antimicrobial resistance?
“Antimicrobial resistance (AMR) is the ability of the infection-causing microbes like bacteria, fungi, viruses and parasites to develop a protective mechanism to overcome the effects of antimicrobials, which are medicines designed to kill them,” says Dr Dipankar Sarkar, consultant internal medicine & critical care, Manipal Hospital, Salt Lake, Kolkata. “Antimicrobials include antibiotics, antivirals, antifungals and antiparasitics.”
According to Dr Sarkar, these microbes undergo morphological changes and release chemicals, that make them outwit the effects of antimicrobials, making infections difficult and sometimes impossible to treat,” says Dr Sarkar. Organisms like bacteria modify themselves using various methods to combat the effects of antibiotics. These include mechanisms like altering their own target molecule so that the antibiotic is ineffective, pumping the antibiotic out of the cell or inactivating the antibiotic.
Dr Sarkar says that antimicrobials resort to different pathways to destroy infection-causing microorganisms. These include dissolving the organism’s cell wall, changing its protein structure and removing the nucleic material. The microbes develop mechanisms to combat the different pathways used by the antimicrobials.
How do the microbes become resistant?
“Antimicrobial resistance can happen naturally over time due to genetic mutations in the bacteria. It can also be acquired by manmade factors like the misuse and overuse of antibiotics,” says Dr Vijayalakshmi Nag, professor and HOD, department of microbiology, AIIMS, Jodhpur, Rajasthan.
The injudicious use of antibiotics includes excessive or prolonged use, acquiring them without a prescription, discontinuation before completion of their course and taking them when not needed.
Elaborating on the misuse of antibiotics, Dr Vijayalakshmi says, “Antibiotics are meant to treat bacterial infections. When a person with fever is prescribed antibiotics without probing whether the cause is bacterial or viral, the bacteria can go on to acquire resistance against the antibiotics.” These resistant bacteria multiply and are transmitted to other organisms including humans, animals and plants.
Dr Asima Bano, professor of microbiology and principal of Bangalore Medical College and Research Institute, Bangalore, lays down measures to prevent AMR. When one has symptoms like a cough or cold, the cause is invariably viral. Later, it may turn into a bacterial infection. But even before waiting for the infection to turn bacterial, people begin antibiotics.
“The misuse of antibiotics had skyrocketed during the COVID-19 pandemic, where the ignorance about the virus led people to misuse them,” shares Dr Bano. She also adds that antibiotics can be prescribed once the bacterial culture test reports confirm the cause of the infection is bacterial. This usually takes around 48 to 72 hours.
Drug-resistant tuberculosis (DRTB) is a form of AMR where the disease-causing bacteria is resistant to rifampicin and isoniazid, the primary anti-TB drugs. Drug-resistant TB has been a roadblock to achieving the strategy — End TB by 2030 globally.
Besides, a recent study titled ‘Association between particulate matter (PM 2.5) air pollution and clinical antibiotic resistance: A global analysis’, conducted between 2000-2018 projects a 17% rise in global antibiotic resistance by 2050 if current air-pollution policies are not improved.
Impact of antimicrobial resistance on public health
According to WHO, antimicrobial-resistant organisms are found in people, animals, food, plants, and the environment (in water, soil and air). They can spread from person to person or between people and animals, including from food of animal origin.
It also states that the following can promote the spread of drug-resistant microbes, impacting public health.
- Lack of access to clean water, sanitation and hygiene (WASH) for both humans and animals.
- Poor control and prevention of infections and diseases in healthcare facilities and farms.
- Poor access to affordable medicines, vaccines and diagnostics.
- Lack of awareness and knowledge.
- Lack of enforcement of legislation.
The UN environmental program mentions that microbial stressors, such as pollution, create favorable conditions for microorganisms to develop resistance in humans and the environment. Bacteria in water, soil and air, for example, can acquire resistance following contact with resistant microorganisms. Human exposure to AMR in the environment can occur through contact with polluted water, contaminated food, inhalation of fungal spores and other pathways that contain resistant microorganisms.
“It takes 10-20 years to develop a new antibiotic. If people increasingly become multi-drug resistant, which is already a reality, we may retract to the pre-penicillin era, where the smallest of infections can snowball into having grave consequences,” opines Dr Bano.
Takeaways
- Antimicrobial resistance (AMR) is the resistance that microbes develop against antimicrobials designed to kill them.
- One of the major causes of AMR is the misuse and overuse of antimicrobials.
- The cause of the infection must be understood before prescribing antibiotics.
- The environment plays a key role in the spread of resistant microbes.
