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Humans have used antibiotics since the early civilizations. Egyptians used mouldy bread to apply them to infected wounds, without knowing about the existence of antibiotics. According to the Cambridge dictionary, an antibiotic is a “medicine or a chemical that can destroy harmful bacteria in the body or limit their growth” .
It was only at the beginning of the 20th century that a German scientist, Paul Ehrlich, discovered one of the first antibiotics against syphilis, arsphenamine. The accidental discovery of penicillin gave the nobel price to Fleming, when some penicillium fungus contaminated the culture plate of a bacterium Fleming was studying, Staphylococcus, and inhibited its growth. Penicillin was in mass production by the second world war and applied successfully to the troops during the D-day invasion of the German occupied territory in Europe. Penicillin was considered a wonder drug and many post-war children and adults were treated with it and and saved their lives. Antibiotics work either by preventing the reproduction of bacteria, or by impairing the formation and building of the cell wall structures. The surfaces of the human body such the skin, mouth, intestines, vagina...etc are covered in millions of individual micro-organisms that don’t do any harm. In fact they help to protect us from becoming infected with harmful microbes. They are known as the normal body flora. Bacteria which are harmful are called pathogens. The number of normal bacterial cells hosting our bodies is of about 100 million. Bacteria are incredibly small, about 0,2 micrometer in diameter (a micrometer is 1000 times smaller than a millimetre). They reproduce very quickly, usually by division. In this process the bacterium, divides into two identical daughter cells. The DNA of the bacterium (genetic material) divides into two (replicates). The bacterial cell splits into two daughter cells each with identical DNA to the parent cell. With the right conditions (temperature, nutrients) some bacteria like Escherichia coli can divide every 20 minutes. In 7 hours one bacterium can generate more than 2,000,000 bacteria. After one more hour the number of bacteria will have increased to about 16,000,000 (http://www.microbiologyonline.org.uk/about-microbiology/introducing-microbes/bacteria) . That’s the reason why we can quickly become ill when pathogenic microbes infect our bodies, like an army that self-reproduces at an incredible speed. That capacity to divide and multiply is also the key to antibiotic resistance. In every division there are errors when the DNA of the bacterium is copied. These errors are called mutations. A bacterium like Staphylococcus aureus can accumulate 300 mutations in about 10 hours (Nature Education 1(1):30, 2008). The mutation rate is so high that a bacterial colony is hardly ever the same. When we touch a tap in the toilet we come in contact with a population of rapidly changing bacteria, so changeable that is already different from the person that left the toilet and the bacteria before us. That sounds scary, but it is the principle of antibiotic resistance. Some of these aleatory mutations will confer resistance to the bacteria when they are in the presence of an antibiotic. Antibiotic resistance has become a major public health issue. The problem exists not only due to the rapid bacterial mutation rates, but also because of the “selective pressures that antibiotics impose”. If a drug-resistant phenotype were to evolve and there were no antibiotic present, then that phenotype would fare no better than any other bacterial phenotype. In other words, it wouldn't flourish, and it might even die out. It is only when antibiotics are used that drug-resistant phenotypes have a selective advantage and survive.” (Nature Education 1(1):30, 2008). Why antibiotic abuse? on the one hand there is over-prescription of antibiotics, even when they are not necessary; on the other hand antibiotics are over-used in the farming meat industry, not only for treating infections in animals but also added in the animal feed as growth factors (AGP, Antimicrobial Growth Promoters). It is well known that some people take antibiotics (and physicians prescribe then) when suffering from flue like symptoms or any other kind of viral infections. However antibiotics are ineffective against viruses. Sad is, that while over-prescription occurs in some countries, in other places of the world children and adults have no access to antibiotics to treat real life-threatening conditions. While some die from pathogenic bacteria because no antibiotics are available, others take antibiotics for no reason and provoke bacterial resistance which is becoming a global health problem. Antibiotic consumption in humans is increasing worldwide, driven by rising incomes, health insurance, and a large remaining burden of infectious disease. Between 2000 and 2010, antibiotic consumption in 71 countries increased by 36%, with Brazil, Russia, India, China, and South Africa (BRICS) accounting for three-quarters of this increase. (The Lancet, 2016, 387: 168-175) According to the UK’s National Institute for Health and Care Excellence, almost a quarter of prescriptions for antibiotics won’t benefit those issued them. Why? Nine out of 10 doctors say they feel pressured to prescribe antibiotics; 97 per cent of patients who ask get them (New Scientist, 30.12.2015). However, is the use of antibiotics as growth promoters in animal farming (swine and poultry overall, cattle in USA, Brazil and Argentina) which is very worrisome for the global health. “Antibiotics have been used in livestock in sub-therapeutic concentrations (for growth promotion and disease prevention) and in therapeutic concentrations (to treat sick animals). Since many antibiotics commonly used in sub-therapeutic concentrations are the same as or similar to antibiotics used in human medicine, there is global concern that drug-resistant organisms may pass from animals to humans and present a serious threat to public health” “ Twenty-seven different antimicrobial classes are used in animals, most of which have human antimicrobial counterparts. Nine of these classes are exclusively used in animals (Page and Gautier, 2012). The top three antimicrobial classes by sales for animal use in 2009 were: macrolides (USD 0.6 billion), penicillins (USD 0.6 billion) and tetracyclines (USD 0.5 billion), three classes of antimicrobials considered as critically important in human medicine” (Global antimicrobial use in the livestock sector, 21-01-2015, OCDE, Working party on agricultural policies and markets) The worst is that according to the OCDE report, “In spite of 50 years of AGP use, definitive conclusions on their effects on productivity are still lacking. There is considerable variability in the growth response to sub-therapeutic antibiotics, according to the species, the age of animals, their genetic potential, and the specific hygiene and management conditions”. Last month, the US Food and Drug Administration reported that sales of antibiotics approved for use in livestock rose by 23 per cent between 2009 and 2014. Much of this use, linked to the growth of antibiotic resistance in humans, is not to treat infections but to promote growth of the animals (New Scientist, 30.12.2015). Antibiotics are an essential element of animal health, but the increasing use of antibiotics in sub-therapeutic concentrations for growth promotion and disease prevention (as a substitute for hygiene) is placing substantial selection pressure for resistance to evolve. Worldwide antimicrobial consumption in animals is projected to rise by 67% from 63 151 (±1560) tons in 2010 to 105 596 (±3605) tons in 2030 (The Lancet, 2016, 387: 168-175). The regulatory situation worldwide is a mosaic of laws. Whereas EU Countries have completely forbidden the use of AGPs in 2006, USA and many other countries allows them, each with different exceptions and specificities. According to WHO, the resistance to antibiotics is becoming critical: “ In 2013, there were about 480 000 new cases of multidrug-resistant tuberculosis (MDR-TB). MDR-TB requires treatment courses that are much longer and less effective than those for non-resistant TB. There are high proportions of antibiotic resistance in bacteria that cause common infections (e.g. urinary tract infections, pneumonia, bloodstream infections) in all regions of the world. A high percentage of hospital-acquired infections are caused by highly resistant bacteria such as methicillin-resistant Staphylococcus aureus(MRSA) or multidrug-resistant Gram-negative bacteria. Patients with infections caused by drug-resistant bacteria are generally at increased risk of worse clinical outcomes and death, and consume more health-care resources than patients infected with the same bacteria that are not resistant. As an example, the death rate for patients with serious infections caused by common bacteria treated in hospitals can be about twice that of patients with infections caused by the same non-resistant bacteria. Re Treatment failure to the drug of last resort for gonorrhoea – third-generation cephalosporins – has been confirmed in several countries. Resistance to one of the most widely used antibacterial drugs for the oral treatment of urinary tract infections caused by E. coli– fluoroquinolones – is very widespread. Resistance to the treatment of last resort for life-threatening infections caused by common intestinal bacteria – carbapenem antibiotics – has spread to all regions of the world. Key tools to tackle antibiotic resistance – such as basic systems to track and monitor the problem – reveal considerable gaps. In many countries, they do not even seem to exist”. ( http://www.who.int/mediacentre/factsheets/fs194/en/ ) The over-prescription of antibiotics and the use of antibiotics as AGPs for use in livestock is an example of the lack of consistency and the lack of a global regulation and governance in a matter (antibiotic resistance) which is of worldwide interest. A question of importance for the global health which cannot be left to the discretion of the meat industry, the private interest and/or the countries which support both. (see Global antimicrobial use in the livestock sector, 21-01-2015, OCDE, Working party on agricultural policies and markets, table 1for the regulatory landscape). The expansion of appropriate access to antibiotics where they are needed while restricting the inappropriate access, in particular to the last generation, last-resort antibiotics requires a delicate balance where an overall worldwide governance is necessary. Reality is that no access to antibiotics kill more people (e.g. pneumonia in children) than antibiotic resistance does (The Lancet, 2016, 387: 168-175). Therefore restricting the abuse and providing what is needed is the way ahead. World Health Organization is clear about it: Without urgent, coordinated action, the world is heading towards a post-antibiotic era, in which common infections and minor injuries, which have been treatable for decades, can once again kill. All for one world, January 2016 |
Why antibiotic abuse? on the one hand there is over-prescription of antibiotics, even when they are not necessary; on the other hand antibiotics are over-used in the farming meat industry, not only for treating infections in animals but also added in the animal feed as growth factors (AGP, Antimicrobial Growth Promoters). Last month, the US Food and Drug Administration reported that sales of antibiotics approved for use in livestock rose by 23 per cent between 2009 and 2014. Much of this use, linked to the growth of antibiotic resistance in humans, is not to treat infections but to promote growth of the animals (New Scientist, 30.12.2015). The over-prescription of antibiotics and the use of antibiotics as AGPs for use in livestock is an example of the lack of consistency and the lack of a global regulation and governance in a matter (antibiotic resistance) which is of worldwide interest. A question of importance for the global health which cannot be left to the discretion of the meat industry, the private interest and/or the countries which support both. |
