Antibiotics have revolutionised the prevention and treatment of bacterial infections, made routine surgeries, transplants, and cancer treatments possible, and saved millions of lives. But the rapid emergence of antimicrobial-resistant infections worldwide now threatens our lives. Superbugs are bacteria, viruses, fungi, and parasites that develop resistance to antibacterial (antibiotic), antiviral, antifungal, and antiparasitic drugs, together referred to as antimicrobials. Antimicrobials play a crucial role in preventing and treating infections in humans, animals, and plants, but their overuse and misuse drive antimicrobial resistance (AMR). Antibiotic-resistant infections can lead to extended hospital stays, additional follow-up medical visits, loss of productivity, and the use of treatments that may be costly and potentially toxic.
PREVALENCE: AMR is a multi-faceted global challenge, a “silent pandemic” considered one of the ten global public health threats to humanity. Globally, an estimated 1.3 million people die each year directly due to bacterial AMR. The World Health Organization (WHO) estimates that by 2050, antibiotic resistance could lead to up to 10 million deaths annually. If no action is taken, this number will increase dramatically, imposing huge costs on public health, agriculture, the economy, and society. It requires greater coordination, political leadership, interdisciplinary and multisector targeted actions by the entire society to safeguard the health of humans, animals, plants, and the environment.
CONTRIBUTING FACTORS: Superbugs mutate to resist newer antimicrobials and vaccines, then spread to other persons or animals, and pass on their resistance to vulnerable microbes, leading to epidemics. Misuse of antibiotics for viral infections such as cold or flu, wrong prescriptions, low-quality medicines, disregard of guidelines for prescribing antibiotics and proper hand hygiene, sanitation, surveillance, infection prevention, and control encourage the development and spread of drug resistance. Pollution from the pharmaceutical, agriculture, and healthcare sectors is a major contributor to antimicrobial resistance. Lack of new drug development due to reduced economic incentives and challenging regulatory requirements adds to the problem.
MICROBIOME: The microbiome is a diverse community of microorganisms, like bacteria, viruses, and fungi, that reside in a specific environment, such as the human or animal skin, and gut, in and on plants, or in the soil. These microbes are crucial to human health, for digestion, nutrition, and immunity. Antibiotic therapy wreaks havoc by eliminating harmful and beneficial bacteria, especially in the gut. Microbiota dysbiosis is an imbalance in bacterial composition and distribution due to the loss of beneficial bacteria and overgrowth of pathogenic bacteria within the gut, with biofilm formation, immune dysregulation, and inflammation. Antibiotics can cause such a bacterial imbalance, leading to feeling sick, bloating, loss of appetite, indigestion, nausea, vomiting, diarrhoea, stomach pain, or cramping.
ROLE OF DIET, PREBIOTICS, AND PROBIOTICS: Diet is important for gut microbiome health and recovery after antibiotic treatment. After antibiotic treatment, a diet high in processed foods, red meat, dairy products, and sugar cannot rebuild a healthy and diverse gut microbiome. A plant-based high fibre diet of fruits, vegetables, and whole grains quickly restores a healthy and resilient gut microbiome by providing the nutrients for the right microbes. A healthy diet before surgery and chemotherapy builds a healthy microbiome that can help defend against infections and reduce the need for antibiotics, preventing the rise of resistant bugs that can spread to family members. Prebiotics are non-digestible food components, primarily fibres, that selectively promote the growth and activity of beneficial microbes. Probiotics, like beneficial bacteria and yeasts, are live microorganisms that can help restore the microbiome. Fermented foods such as yoghurt are a rich source of probiotics.
ANTIBIOTIC MISUSE IN AGRICULTURE: An estimated 80% of antibiotics sold in the U.S. are used in animals, primarily to promote growth and to prevent infection. Treating livestock with antimicrobials is claimed to improve the overall health of the animals, producing larger yields and a higher-quality product. The antibiotics used in livestock are acquired by humans when they consume meat products. The transfer of resistant bacteria to humans by farm animals leads to high rates of antibiotic resistance in the intestinal flora of both farm animals and farmers.
The agricultural misuse of antibiotics also affects the environmental microbiome. Up to 90% of the antibiotics given to livestock are excreted in urine and stool, then widely dispersed through fertilizer, groundwater, and surface runoff.
In addition, tetracyclines and streptomycin are sprayed on fruit trees to act as pesticides in the western and southern U.S.
UNINTENDED ADVERSE EFFECTS OF ANTIBIOTICS: Prolonged or repeated antibiotic use, especially in pregnant women and children, has unintended long-term health consequences. Major studies link antibiotic use with colon cancer, several chronic diseases, including allergies like asthma, autoimmune diseases like inflammatory bowel disease (IBD), metabolic diseases like obesity and diabetes, and psychiatric diseases like depression, anxiety, and psychosis. Careful and judicious use of antibiotics in infants is important, as a South Korean study of 322,731 children discovered that girls (but not boys), who received antibiotics before three months of age, were 33% more likely to experience early puberty. Overuse or unnecessary use of antibiotics in early life can affect a child’s developmental trajectory. Antibacterial products sold for hygienic or cleaning purposes may also contribute to this problem, since they may limit the development of immunities to infections that wouldn’t normally be virulent.
PREVENTIVE MEASURES: Awareness, especially of appropriate antibiotic use, antibiotic resistance, its dissemination, and potential threats, can greatly help in controlling the use and abuse of antibiotics and the containment of antibiotic resistance. One should take antibiotics exactly as prescribed and not stop early or share any unused medications. Meat, fruits, and vegetables can be contaminated with AMR bacteria that need decontamination. Recently approved antibiotics and novel approaches to bacterial infection treatment provide hope. Coordinated efforts by all stakeholders, like civil society, research and academia, the private sector, regional, intraregional, and international organizations, governments, and philanthropic organizations to implement new policies, renew research efforts, and pursue steps to manage the crisis are greatly needed. Although considerable human and financial resources investment is necessary, the cost of not acting will be much greater.
Dr. P.S.Venkatesh Rao is a Consultant Endocrine, Breast & Laparoscopic Surgeon, Bengaluru.