The Council of Ministers of the European Union (EU) has issued several recommendations to the EU member states with the purpose of diminishing the use of antibiotics. Earlier, a large part of the antibiotics consumption was used as feed additives in husbandry and to some extent also in plant agriculture. The use in animals was based on the empirical but not completely understood observations that meat animals gained weight faster when given antibiotics in their fodder. It soon became clear, however, that this practice led to the spread of antibiotic resistance through the food chain into the general population. An example of this was the use of avoparcin, a glucopeptide, an analog to vancomycin. It was approved for growth promotion within the EU, particularly in the breeding of poultry. Substantial amounts were used. In one EU country in1993, for example,22kg of vancomycin was employed in human therapy, while animal use consumed 19,000 kg of avoparcin. It soon became clear that this practice led to a widespread dissemination of vancomycin resistant enterococci into the general population through the food chain. This was all the more frightening since vancomycin was looked upon as a drug of last resort in many cases of infectious disease. It is the drug of choice for the treatment of infections by methicillin-resistant staphylococci. Avoparcin was banned from livestock feed in the EU in 1997 after more than two decades of use. In monitoring the effect of the ban, a dramatic drop in the occurrence of vancomycin-resistant enterococci was seen in chickens and supermarket chicken meat. This could also be seen in stool samples from patients in which the prevalence of a key vancomycin resistance gene dropped from 5.7% to 0.8%, clearly demonstrating the good effect on resistance of restrictions in antibiotics distribution.

There is another interesting example of the consequences of using antibiotics for growth promotion in animal husbandry. It regards streptothricin, found in the Streptomyces screening efforts performed in Selman Waksman’s laboratory described in Chapter 1. Streptothricin was found to be too toxic for human use but was used under the name nourseothricin for growth promotion in pig farms in the earlier East Germany. Soon after the introduction of streptothricin use, plasmid-borne resistance to streptothricin was observed in E. coli bacteria from nourseothricin-fed pigs and from employees and their family members on pig farms. Streptothricin resistance plasmids were furthermore found in E. coli isolated from the gut and from the urinary tracts of people with no connection to pig farms but living in villages and towns in an area where streptothricin was used in animal husbandry. These examples illustrate the rapid emergence of antimicrobial resistance and their powerful mechanisms of spread. Further investigation showed that the plasmid-borne gene mediating streptothricin resistance was in turn borne on a transposon on the plasmid. This transposon was also found to carry a gene for spectinomycin resistance. This means that the use of streptothricin not only selected for streptothricin resistance but also co-selected for resistance to an important antibacterial drug used in human medicine.

Antibiotics have also been distributed in plant agriculture: for example, in combatting the devastating plant disease of fire blight caused by the bacterium Erwinia amylovora and causing severe losses in apple and pear production. In the United States, 12to13metrictonsofstreptomycinwereusedinthemiddleofthe 1990s for the purpose of fighting this plant disease. Streptomycin resistance of a type recognized from human pathogens quickly appeared in Erwinia amylovora, and the practice was abandoned.

In later years, laws have been introduced in the EU to stop the use of antibiotics for growth promotion. This is a good example of cooperation within the EU to try to solve the ecological problem that the overuse of antibiotics really is. There also seems to be a remarkable overuse of antibiotics in health care. In this area, however, international laws for the strict use of antibiotics are difficult to introduce, since health care is a national responsibility within the EU. The national government within each member country is finally responsible for the health problem of increasing antibiotics resistance and the necessary restrictions in the distribution of antibiotics. Surveillance of resistance has to be improved and information campaigns initiated. There is an international organization for this purpose, the Alliance for the Prudent Use of Antibiotics (APUA, 75 Kneeland Street, Boston, MA02111; web site: www.APUA.org; email: APUA@tufts.edu). This is an association with representatives from more than 20 different countries. It is dedicated to ‘‘preserving the power of antibiotics.’’

The total consumption of antibiotics is not alone to blame for the rapid development of resistance. This can be concluded from the resistance situation in developing countries such as Bangladesh, Nigeria, Sri Lanka, and Vietnam, where the consumption of antibiotics per inhabitant is less than a tenth of that in the industrialized world. Still, as described from sporadic reports, the resistance situation is much worse. This is due to the fact that antibiotic therapy cannot be well aimed because of insufficient resources for bacterial diagnosis and resistance determinations. Furthermore, antibiotics can be bought freely in the local market and are therefore often used incorrectly against insusceptible pathogens and in inadequate doses.

اخر الاخبار

اخبار العتبة العباسية المقدسة

قسم الشؤون الفكرية يختتم المرحلة الثالثة من مشروع استعادة مكتبة جامعة الموصل

جامعة الكفيل تنظّم دورة حول نظام (كوها) العالمي لإدارة المكتبات الجامعية في النجف

مجموعة مشاتل الكفيل: إضافة نحو 70 نوعًا جديدًا من المغروسات تتناسب مع الظروف المناخية المحلية

المجمَع العلمي يطلق الدورة التطويرية الخامسة لمعلمي التربية الإسلامية ومدرسيها في النجف الأشرف

المزيد

الآخبار الصحية

اختراق علمي.. دواء يؤخر ظهور السكري من النوع الأول لسنوات

هذا ما يحدث لجسمك إن أهملت نظافة فراشك

لماذا تعتبر النساء أكثر عرضة للإصابة بألزهايمر من الرجال؟

لماذا يحذر الخبراء من الإفراط في تناول الفراولة؟

المزيد

الآخبار التكنلوجية

السيارات الكهربائية أنظف بنسبة 73% من سيارات الوقود

سيارة لوسِد الكهربائية تدخل "غينيس" بأطول مدى في العالم

نظرية جديدة تنسف كل ما نعرفه عن تشكل أول قارة في الأرض

منذ 37 ألف عام.. دراسة تكشف "أقدم أمراض" أصابت البشر

المزيد

مواضيع ذات صلة

International Distribution of Antibiotics: A Scandinavian Example

Rediscovery of Penicillin by a Basic Scientific Approach

Penicillin: the First Antibiotic

Sulfonamide: the First Antibacterial Agent Acting Selectively

Drug elimination

Drug distribution

Dose–response relationships

السلفوناميدات

Antibiotic Resistance

البنسيلينات Penicillins

المضادات الحيوية المثبطة لصناعة الجدار الخلوي

Aminoglycosides and spectinomycin