Antimicrobial Resistance: Sifting Fact from Fiction
Pashudhan Praharee,22nd Jan 2021
Tarun Shridhar
Former Secretary Ministry of Fisheries, Animal Husbandry and Dairying, Govt. of India
Serendipity! It couldn’t have been more delightful, or more “healthful”; the month of September in the year 1928 when
Dr. Alexander Fleming, the bacteriologist of St. Mary’s Hospital, London, returning from a vacation found that besides a messy laboratory, the Petri dishes had been contaminated by a mold called Penicillium notatum; and this mold had prevented the growth of staphylococci, a bacterial human pathogen residing in the respiratory tract. Conclusion was straightforward, some characteristic of the Penicillium mold not only inhibited the growth of bacteria but could be effectively harnessed to combat infectious diseases. This was the world’s first officially recognised antibiotic. Though for centuries, across civilisations, mold had been used effectively to treat infected wounds, the scientific basis of this treatment was either not known or not understood; in any case there is no documentation. It would take another 14 years, when in the year 1942, the first patient would be treated, successfully, with penicillin; Anne Miller of the USA lying near death on account of blood poisoning induced by a miscarriage. Discovery of penicillin marked a turning point in human history; doctors now had a drug that could completely cure their patients of deadly diseases. Since then antibiotics, substances that destroy bacteria, are widely used for prevention, control and treatment of diseases and infections.
Like people, animals too fall sick; and develop symptoms quite similar. So antibiotics have been an integral part of the animal husbandry system. At first, the usage was confined to treatment of sick animals graduating to surgical practices including Caesarian section in farm cattle. Later on, with a moderate intensification of livestock farming, the usage of antibiotics included disease prevention and growth promotion. It is here that the controversy arose and the entire bouquet of woes of human health were attributed to Antimicrobial Resistance (AMR) on account of its infiltration into the human food chain through livestock.
The United Nations’ Food and Agriculture Organisation (FAO) defines AMR as “the ability of micro-organism to persist or grow in the presence of drugs designed to inhibit or kill them. Standard treatments are then rendered ineffective and drugs lose their therapeutic effect. Treatments fail, resulting in illness and mortality in humans and animals.” While recognising the challenge to management of human and animal health posed by AMR, it is also important that we accept that antibiotics are as essential for protection of livestock, poultry and fish health as they are for human health. After all, antibiotics are substances that can destroy disease causing bacteria, and thus have been widely used for prevention, control and treatment of diseases and infections. In fact, centuries ago civilisations as far apart as Egyptian, Chinese, Indian etc. made use of molds to treat wounds, recognising their efficacy even though they may not have understood the science behind this practice.
Antibiotics are an integral part of comprehensive animal husbandry practices. Growing population, expanding middle classes and urban migration lead to an increased demand for food and nutrition. This puts extra pressure on food production and supply chains & systems. As a result, livestock production systems are becoming more intensive to meet this ever rising demand for animal proteins and dairy products. Here, antimicrobials perform a significant role not only to manage livestock diseases, but also to boost growth, improve feed utilisation, enhance productivity, and most importantly reduce morbidity/mortality rates. The extent of use of antibiotics depends upon several factors, the most important being the livestock production systems. Good animal husbandry practices inevitably lead to a reduced dependence on drugs. A case in point is Salmon farming. Norway produces more than half the world’s Salmon using only 1 tonne of antibiotics a year; China, on the other hand, uses 300 tonnes for about only 4% of the global production. Husbandry systems where a large number of animals are kept in small spaces tend to compromise hygiene and bio-security; thus lending themselves to an increased use of antibiotics. Even though a few animals may be sick, all get treated to prevent spread. Moreover, driven both by demand and commerce, the use of antibiotics has moved from therapeutic to prophylactic to feed additives for growth promotions.
Here lies the problem. While prudent use of antimicrobials is critical to treat animal diseases, inappropriate and excessive use in both human and veterinary health care exacerbates the problem as AMR is a phenomenon which otherwise also occurs naturally over a period of time. Each and every use of antimicrobials in people and animals is an opportunity for the micro-organisms to develop greater ability towards resistance over a period of time. Codex Alimentarius, a collection of internationally adopted food standards aimed at protecting human health, calls AMR “a major global threat of increasing concern to human and animal health.” This description may appear dramatic and an exaggeration, however, it is well established that presence of antimicrobial resistant micro-organisms in agriculture production systems and food chain is a potential route of exposure for everyone. FAO attributes about 7 lac human deaths a year to AMR related infections. Once the food chain gets contaminated, AMR can spread among different hosts and environments. 70 to 80% antibiotics given to fish are excreted into water, so obviously they spread far and wide through the water systems. Similarly, 75 to 90 % antibiotics are excreted from animals unmetabolized, entering the environment posing threat to both human and animal health.
When it comes to use of antibiotics in livestock, poultry and fisheries sector, we are in a data poor situation. In an approximately US$ 25 billion global animal health market, the estimates of consumption of 27 different classes of antibiotics vary between 63,000 to 2,40,000 tonnes per year. 60% of all antibiotics produced are used in animals and even the future growth of more than 65% is projected to be in the livestock sector. FAO assesses that in poultry and piggery its use will double in the current decade. Antibiotics are a boon for protection of human and animal health when their role is confined to treatment of diseases, but when misused or consumed indiscriminately for scientifically unsubstantiated purposes such as growth promotion, they result in AMR pathogens risking the food systems, livelihoods and economies. US$ 3.4 trillion is the estimated loss on account of AMR to the world’s GDP in the last ten years.
A balanced, rational approach is to recognise both the immense benefits of antibiotics in human and animal health systems as also the potential threats of imprudent consumption. The rising clamour for a blanket ban on use of antibiotics in livestock is akin to a self goal. Much greater quantities will obviously be used in animals as the global combined weight of livestock and poultry is more than three times the weight of humans. Our approach should be scientific and dictated by common sense rather than sentiments and ignited passions. A leading newspaper, a couple of years back, carried a headline “India’s poultry farms are spawning superbugs;” a prestigious academic institution published a research paper recently which claimed that India has emerged as a global hotspot for AMR. Nothing could be farther from truth. No doubt, there is unregulated antibiotic use, and there is the problem of AMR, but one important data must be remembered before drawing any inference: 80% of antibiotics in the livestock sector are consumed by swine and cattle. Our cattle farming is a smallholder production system, the average holding size being 2 or so cattle; while swine farming is negligible. Therefore, the use of antibiotics in our livestock sector is minimal. Global use in poultry and fish is less than 10% each, and here too bulk consumption is only in large organised farms and systems.
Considering that no major new types of antibiotics have been produced in the past few decades; and quite a few known ones are fighting a losing battle against pathogenic micro-organisms, we must guard our available antimicrobials through judicious use so that growth of drug resistant bacteria is checked. A few simple steps to combat AMR in the livestock sector would be improving environmental hygiene, better nutrition to animals, good husbandry practices and management, accessible and reliable veterinary services, disease prevention through vaccination etc. Preservation and promotion of indigenous breeds would also be an effective strategy as these breeds are naturally sturdier in the face of pathogens. Above all, a strong and effective regulatory regime is a sine qua non to manage this global challenge. Knee jerk solutions like elimination of use of antibiotics across a range of animal health issues would be regressive, much like throwing the baby out with the bath water.
